COAL RESEARCH ESTABLISHMENT OF THE NATIONAL COAL BOARD Annual Report April 1984 to March 1985

Copies available from: Reports and Intelligence Branch Coal Research Establishment Stoke Orchard, Cheltenham Gloucestershire GL52 4RZ United Kingdom

@NCB Coal Research Establishment 1985 Introduction

The Coal Research Establishment is responsible for the NCB Research and Development programme in coal utilisation. A large part of this programme is devoted to supporting and expanding the markets for burning coal. The rest of the programme is divided between coal products, coal conversion and general studies.

Combustion There has been a continued increase in the total installed capacity of fluidised bed boilers and furnaces, many of which were designed using technology which originated with CRE. In addition, novel applications of the technology such as fast fluidised beds, thermal fluid heaters and twin bed combustor/pyrolysers are at an advanced stage of development. More conventional industrial combustion equipment continues to be improved and the installed or ordered capacity of this improved equipment now stands at 250 MW (thermal). Clean and effective coal and ash handling is essential in a modern coal-fired boiler house and improvements in suction nozzles, silo storage and incremental coal feeding continue to be made. Containerisation and other approaches to coal delivery and reception are being demonstrated. During the past year work has commenced to develop and apply coal-water mixture technology to UK coals. Following laboratory studies and assessments, a pilot-scale preparation facility has been designed for construction during 1985. Independent domestic boilers rated at 17.5 kW (60,000 Btu/h), using the self-cleaning underfeed stoker are to be marketed during 1985. Larger versions (25-50 kW) are performing well in field trials and models for approval testing are being constructed by the manufacturers. Units rated at 150 kW should also become available for the commercial market during the coming year. These, and the larger domestic units, will be fitted with an automatic ash removal system developed at CRE. A 12 tonne/day gasifier has been constructed and commissioned at CRE to demonstrate the NCB fluidised bed gasification process at a scale approaching that envisaged for commercial operation. A new Power Generation Branch has been established at CRE with the principal aim of developing pressurised fluidised bed combustion as a basis for combined cycle power generation. The 20 bar pressurised combustion system, originally constructed at CURL, Leatherhead, has been re-built at CRE after extensive modification, and a computer control system is being installed. The measurement of emissions and the improvement of pollution control technology are continuing activities at CRE. Support is also provided to the NCB Minestone Executive to maximise the use of colliery waste in civil engineering applications and to characterise waste products from existing and novel coal utilisation technologies.

Coal Products Several new construction products have been developed for Thomas Ness Ltd. and work on chemical products has produced new solvent treatment processes, improved froth flotation oils, and better methods for treating tars as precursors for electrode binder pitch. Support has been provided for National Smokeless Fuel Ltd. in the manufacture of smokeless fuels and metallurgical coke. The work on coke has focussed on means of producing cokes with improved resistance to alkali attack in the blast furnace, and on determining the proportion of low rank coal that can be included in coking blends without adversely affecting the strength of the product or causing problems during oven discharge.

Liquid Fuels and Chemical Feedstocks Design work is proceeding on the 2.5 tonne/day pilot plant to be built at Point of Ayr, North Wales for the development of the liquid solvent extraction process for converting coal to distillate products. Supporting experimental work has been to study process options and to develop a mathematical model of the process. The studies of alumina-silicate catalysts for the conversion of methanol have yielded substantial improvements in catalyst life and a possible route for preparing the catalyst on a semi-continuous basis.

General Studies New chemical and spectroscopic procedures are being applied to the analysis of coals with the particular aim of establishing relationships between the chemical structure of coals, including the associated mineral matter, and the nature of the fouling, corrosion and environmental pollutants encountered in combustion and conversion processes. Technical and economic studies continue in support of current research, as contracts for external agencies, and as a means for evaluating proposed new projects. A.O. DAINTON Director

Two Contents

Combustion Fluidised bed combustion 6 Industrial firing (non-fluidised bed) 14 Industrial boiler test house 15 The automated boiler house 15 Coal water mixtures 15 Coal and ash handling 16 Domestic and commercial heating 17 Industrial gasifiers 21 Power generation 22 Environment 24 Waste utilisation 24 Coal Products Chemical products 25 Construction products 25 Smokeless fuels 26 Metallurgical coke 27 Liquid Fuels and Chemical Feedstocks Liquefaction 28 Pyrolysis (direct conversion) 28 Chemical synthesis 29 General Studies Basic coal science: coal characterisation 30 Computer modelling 31 Technical and economic studies 31 Combustion Systems Limited 32 Publications Papers 33 Patents 36

Three .... ·-- .....~ _ ------Combustion

THE expansion of the industrial coal burning 230 MW for furnaces). In addition a number of market is a major objective of the NCB's market­ new ways of using this technology are approach­ ing organisation. The government, in recognition ing commercial status in the United Kingdom. of the efforts of the industry to maintain supplies These include the use of fast fluidised beds, the through the difficulties of the past year, has development of thermal fluid heaters and apply­ agreed to a further extension of the coal grant ing the principle of combined pyrolysis and scheme. Partly because of this, and partly because combustion of coal to generate very hot gas for use of the industry's succE'ss in supplying customers, in furnaces or boilers. the level of enquiries for new coal firing plant Developments on more conventional coal firing remains high. Therefore the corner stone of CRE's equipment continue and the installed or ordered programme of work is to support this potential capacity for this technology has increased to the expansion by developing new and improved equivalent of 250 MW. The GWB Tipping Grate means of burning and handling coal; approxi­ has been particularly successful with orders mately half of the CRE budget is devoted to these doubling from around 20 units to 40 during objectives. As before CRE undertakes small scale 1984/85. The establishment has also started a small investigations and laboratory work before enter­ programme of work to investigate coal-water ing into collaboration with manufacturers to mixtures so that advice and guidance can be given achieve commercial status for the various develop­ on the exploitation of this new technology. ments. A side effect of the industrial action within the During 1984/85 the fluidised bed boiler capacity industry during the past year has been the installed or on order has increased from the figure temporary suspension of Industrial Open Days. of 270 MW reported in the last annual report; it However, these are scheduled to recommence in now stands at a figure of 440 MW for boilers (plus the Spring of 1985.

Two 4.2 MW EMS Thermplant vertical fluidised bed boilers at Avon Cosmetics, Northampton.

Opposite: Fluidised bed gasifier (12 tonne/ day) under construction at CRE.

Five Fluidised bed combustion Shell boilers During 1984/85 substantial, on site, support has type horizontal shell boiler, formerly at the Coal been given to EMS Thermplant, Wall send Slipway Research Establishment, has been installed at Engineers and Babcock Worsley. Many of the Rists Ltd, Newcastle-under-Lyme, alongside the units have now been handed over to the cus­ locomotive-type boiler which was one of the NCB tomers so that by the end of the year field activity fluidised bed prototypes. The Wallsend unit has was reducing. been handed over to the client but the control A major commitment has been to support EMS strategy is th e subject of continuing investigation. Thermplant w ith their install ation at Avon Cos­ Assistance has been provided to Ba bcock Wors­ metics in Northampton. These boilers are now ley in developing their range of vertical and operating satisfactorily and have been han ded horizontal shell boilers. In particular, the opera­ over to the client. A number of visits were also tion of a 1.8 MW vertical shell boiler has been made to Queens University, Belfast to assist EMS monitored, and work is in progress to provide Therrnplant to commission the boilers; formal automatic bed cleaning and an improved boiler opening of the boilerhouses and acceptance by the control system. client are planned for May 1985. Technical support The test and development programme on the and advice has also been provided for the pre­ GWB 2.4 MW horizontal shell boiler has been combustor unit developed by EMS and being completed. The programme included tests of a demonstrated at a site in South Wa les. In view of novel air distributor suitable for use w ith high ash the potential of this concept, the design range has coals. Ancillary equipment has been provided to been extended and the drawings completed dur­ facilitate automatic operation, in preparation for ing the year. transferring the boiler to a commercial site. Wallsend Slipway Engineers have completed Advice has been given to Fluidised Combustion their obligations with respect to sites at Dunlop Ltd on topics arising from their installations in (Grimsby) and Brymbo Steel (part of the GKN Yorkshire which require technical development; grou p) in North Wales; the 7 MW unit at Dunlop negotiations are in progress to undertake collabor­ (S peke) is still being commissioned. The proto- ative projects with this company.

2.4 MW Vekos 11orizo11tnl fluidised bed boiler.

Flue Gas

Pilot Burner & Flame Detector

Bac~End Re·cycling -Wf---Af~~l ll Main Gas

Forced Draught Air

Aerodynamic Sieve for Bed ....­ Cleaning

WaterCirculating Pump

Six Babcock "Fluidbu rn" boilers (20.8 MW) being installed at Reeds Paper Ltd. Maidstone.

Water-tube boilers Five Babcock 'Fluidburn' boilers are now opera­ Operation of the 30 MW M.E. coil boiler at River tional, fo ur are being installed, and a further five Don has been affected by the industrial acti on in are being manufactured giving a total capacity of the coal industry and the test programme has been 222 MW. All these units are intended for continu­ delayed. However, successful demonstrations of ous operati on which represents some 200,000 dual-fuel firing, together with a number of minor tonnes of industrial coal per year. A metal wastage developments were completed in su pport of the problem has occurred on one boiler and possible potential Tate and Lyle order for three x 34 MW solutions are being tested, both on the boiler itself units. The order has now been placed with ME and on a cold model specially constructed for the Boilers and a 6 MW test ri g has been built and investigati on. The 'Fluidburn' range now covers commissioned at their Peterborough works with outputs from 4.3 MW to 21 MW and, in addition to the purpose of demonstrating various aspects of the units listed above, includes a fully water­ the designs of the boilers and to validate the tubed bi-drum d esign installed and operating in proposed arrangement of heat transfer surfaces. Australi a. The Senior Greens 3 MW boiler which operated with a shallow fluidised bed firing system a t their Availabilities in excess of 90% have been maint­ Wakefi eld works has now been transferred to the ained on the 15 MW and 7.1 MW Gibson Wells CRE test boiler house. A combustor/pyroliser boilers w hich have now accumulated 20,000 hours firing system is being m anufactured to fit the unit. of operation between them. The experien ce ac­ This novel firing system, developed at CRE and quired from these boilers was used to assist the described in greater d etail under 'Furnaces', has design of a 10 MW u nit which has been install ed, not hitherto been used in conjunction with a commissioned and handed over to the customer, boiler. Robinsons of Chesterfield, on schedule.

Seven Gibson Wells 10 MW water-tube flu idised bed boiler at Robinsons, Ch esterfield.

Char Conveclk>n Combustor Pass

Combustible Gas Oxygen Rk:h Gas Mixed Gas

Eight Collaboration with Foster Wheeler Power Prod­ conventional design but also extends the range of ucts Ltd is continuing in a number of projects. In application of the technology down to lOMW 1984/ 85, FWPP commissioned a 30 MW boiler in capacity. A site for a commercial prototype is now Kerry, Eire, utilising the Battelle multi-solid being sought. fluidised bed combustion system (MSFBC) and the opportunity was taken to burn anthracite duff A prototype combustor, designed to burn the on this unit. Preliminary results indicate com­ residual carbon remaining in the fl y ash produced bustion effi ciencies above 97% and a further trial from an FBC boiler, has been built and operated at is proposed. Meanwhile, a low cost MSFBC boiler, FWPP Hartlepool. Initial results were encouraging utilising a modular design concept, has been and modifications are being carried out to allow designed by FWPP. This not only offers prospec­ continuous operation over a wider range of grit tive ca pital savings of some 30% against the feed rates. Mod11lnr design of multi-solid fluidised bed combustion llllit with boiler. -

Flue Combustor

I

Convective ' boiler ----...-'1--...,_... Secondary air inlet

Cold re· cycle and external heat exchan er ~--+----"-....

--- Dense bed Primary air distributor

~CR8

Nine Furnaces This year has seen a s ubstantial increase in sales The twin-fluidised-bed combustor/ pyroliser at of furnaces for direct drying and waste CRE has demonstrated significant reductions in incineration, both in UK and overseas. NOx emissions compared with conventional Babcock Worsley Ltd have supplied two units to single-stage combustors. Several manufacturers Italy and one to South Africa for slag drying in the have shown interest. in using this technology. cement indus try; a further s ix units are being Scale-up of the twm bed furnace for semi­ made under licence in Italy and North America. fn co ~merc i al applications up to 3 MW is p racticable England a 10 MW unit with a separate recycle using the present SO mm partition wall between system and equipped for fully automatic control the beds, bu.t .most industrial processes require has been installed near Banbury for drying coffee greater capac1t1.es and for these a thicker dividing grounds. Four furnaces with waste-heat boilers wall, c:>ffenng improved mechanical stab ility, is have been install ed at local authority s ites in the essen tial. Accor~!n g ly, t~e experimental furnace Midlands and North West to burn waste-derived has been mod1hed to incorporate a 150 mm fuels, and two 10 MW coal d rying units designed divi si~m ~all '. with means for fluidising the to burn pelletised fines from froth fl otatio n a re on material w1thm the transfer port. Because this order for Hem Heath Colliery. gave better control of particle transfer between the beds, a combustible gas of calorific value 3.6 Two furnaces for drying sugar beet, designed 3 and constructed by Fluidised Combustion Mj/m could be produced in the pyroliser. This Contractors Ltd. (FCCL) and rated at 35 and 42 allowed operati on at lower excess air levels (30%) MW, have been install ed at British Sugar sites to and hen ce the generation of higher gas replace oil fired units. Both have successfully temperatures (1500°C). In addition , a series of tests completed their first drying campaig n of around were carried out to determine the feasibility of 2500 hours and a further unit is to be ins talled lighting-up one bed from another. The data during 1985. FCCL are currently tendering for obtained related the rate of heating in the second similar furnaces to be installed in 1986. bed to the number of transfer ports in operation and has been used in a mathematical model for predicting the start-up characteristics of larger fluidised beds.

Babcock Worsley 10 MW fl uidised bed furnace nt Cherwell Valley Silos Ltd. , Banbury.

Ten Flue gas outlet Coal feed "

i i

Fluidised plaster bed Central coal fired fluidise.d bed Fluidising air

Fluidised bed plaster cnlciner.

The Peabody Encomech 2.3 MW clean air heater at Bass Maltings, Mirfield has completed over 8000 hours of fully automatic production service, and continues to be an effectie demonstration of coal firing applied to a clean food product. Peabody A commercial cuboid calciner, rated at 20 t/h of Encomech have received numerous enquiries plaster product, has been installed at the British from potential customers for this type of unit. Gypsum works at Gotham. An order for a similar The detailed d esign of the first coal-fired unit has been placed with Babcock Worsley by fluidised-bed thermal fluid heating system (5.3 Gyproc Benelux of Belgium. Following successful output) has been established and manufacture is pilot plant trials, British Gypsum are preparing a almost complete. The thermal fluid, heated to scheme to use a 6 MW high velocity furnace to 280°C, will be used to generate clean hot air for supply hot gas to fire a new conical kettle rated at plasterboard drying at a British Gypsum site. 25 t/h of plaster product, which is to be installed at Computer assisted modelling has been used to their Kirkby Thore works. develop a novel control system for this heater.

Eleven Fluidised bed su pport studies Both untreated as well as treated coals are being Equipment has also been developed for burned in industrial fluidised bed boilers. When removing oversize material automatically from un treated coals of high ash content are used, much several po i nts within a fluidised bed. of the ash accumulates in the bed and, as with Contaminated bed material is sequentially treated fuels, the oversize and dense particles can injected from a number of bed drain tubes into a be removed by bed cleaning devices. However, a common pneumatic conveying pipeline fo r proportion of the ash is in the form of smaller transportation to a single static inclined cascade particles and during operation, as material is screen where the oversize material is removed and drained from the bed to maintain the correct correctly sized material is returned to the bed. The height, the original sand bed may largely be material is introduced into the conveying pipeline replaced by these particles. This changes the by 'L' ejector valves sited between each of the characteristics of the bed and tests have been drain tubes and the conveying pipe and activated carried out on a water-tube rig using a range of by air jets. The ability of this system to extract high-ash coals, to determine the rate at which the contaminated bed material from several points ash accumulates in the bed and the effect this has within a bed makes it particularly suitable for on bed expansion and heat transfer. The data large units. Five boilers are currently operating obtained have been applied to boiler designs in with this method of bed regrading. order to determine the bed cleaning requirements Detailed design studies of in-bed tu be layouts and to allow predictions of boiler performance. have been carried out for a number of Babcock Oversize material can be removed from a Power 'Fluidburn' boilers and also for the M.E. fluidised bed using a single off-take at the lower Coil boilers to be installed at Tate and Lyle. end of a slightly sloping air distribrutor fitted with directional air nozzles. This technique for improving the mobility of the large ash particles has been demonstrated on a commercial boiler burning a coal containing 25 % ash. General arrn11ge111ent of bed re-vnding system for n fluidised bed boiler.

Twelve Directionnl nir nozzles to AIR JETS ASSISTING remove seg regn ted CROSS MIGRATION mnterinl fro m n fl uidised bed.

BED MATERIAL PLUS SEGREGATING LARGE ASH

In order to encourage the widespread applica­ Cold models have been used to simulate the tion of fluidised bed combustion as the firing wear in boilers and also to study fl ow patterns. It method for industrial boilers it is important to has been found that solid's flow at walls is demonstrate that the d esigns will give satisfactory generall y downward and horizontal shelves can operational lifetimes. However, commercial oper­ be fitted to prevent abrasion of the wall metal. ating experience has indicated that certain parts of Wear of tubes is related mainly to flu idising a boiler in contact with a fluidised bed environ­ velocity and to position relative to the fluidised ment can erode unacceptably. As a result, a bed surface. Flow disruptors (such as fins, discs n umber of commercial boilers are being regularly and pegs) have been shown to be effective and the monitored and computer-based methods of stor­ use of more resistant alloys and surface coati ngs is ing and processing the data are being developed, also being examined. together with means of displaying the results in graphical form.

Wenr pnllern s 0 11 wnl/ tub es i11 n flu idised bed cold 111 odel (revealed by the 111ulti-Jnyer pni11t tech11iq11e).

T/iirtee11 Industrial firing (non-fluidised bed)

The GWB Tipping Grate (Ashmaster) continues A prototype vibrating grate stoker built by to sell well. At the end of las t year 22 units we re James Proctor has been under test in the CRE test reported as being installed or on order a nd the boiler house. Early d iff iculties in controlli ng the total at the end of1984/85 now stands at 41. When vibration have been overcome s ufficiently to installed, these represent a total capacity of enable test firing over periods of days and a approximately 200 MW with an estimated coal development programme has been defined for the burn in excess of 150,000 tonnes per year. Dev­ coming year. elopment effort on the tipping grate has been Sales have continued of James Scott side-grate concentrated on providing an alternative ash de-as hing unde rfeed stokers, based on NCB removal system and reducing smoke emission technology, and existing units have performed during ti pping. The latter has been achieved by satisfactorily. These s tokers are now available in means of improved devices for promoting over­ sizes ranging from 0.5 to 1.8 MW. bed mixing of combustibles and ai r. Commercial designs of the Escom s toker have A number of Proctor mini coking-stokers are been completed for two unit sizes (0.6 and being installed and commissioned at Property 1.2 MW), and initial sales have been made by the Services Agency sites. The design range has been coll aboratin g manufacturer, Hartley and Sugden. extended to 8 x 106 Btu/h (2.3 MW) and two units of this size are about to be commissioned.

Undergrate Damper Controls ~--Ash Drop Tube lsolation -----t:~P«~t""'" Springs

Tuning Weight

Exciter Springs VIBRATING GRATE STOKER "CRE Fo11rtee11 160tonne Vitreous Enamel Stool Silo

5·BBMW CoollngTowor (Water; Steam)

Denso Phase 20tonne Secondary Coaj Handling ~~~~se System Systam tor Main Grit and Dust Coal Delivery Sampling Polnts--1!.'>- """'1_,,,.,;:;:r;.::r,

Atmospheric and Pressurlud Hot Water Heal Exchangers (5·B6MWtotal)

5MW Capacity 5MW Boller Bays Vertical Boiler Bay

Sub·surfaca Service Ducts Bag Filler System '------for Eldlaust Gas Clean-up

INDUSTRIAL BOILER TEST FACILITY

Industrial boiler test house Coal water mixtures (cwm)

The boiler test house has continued to provide a During the past year, studies have been i niti­ facility for the demons tration and development of ated on the development and application of cwm industrial boilers and associated equipment and technology to UK coals. The work includes both the work is being ex tended into the areas of coal laboratory studies and technical assessments of and ash handling and water treatment. A bag filter industrial firing trials. system has now been ins talled and commissioned. The principal objectives are to explore alterna­ This will be used to reduce emissions from the tive m ethods of preparing stable mixtures from building and for performance tes ting of filter b ag various coals, to identify the most economic materials. preparation route, and to establish the technical Work has commenced to modify the building to requirements fo r converting an industrial boiler make it s uitable for testing industrial boilers to from oil to cwm firing by carryin g out combustion British Standards. trials. Current laboratory studies are concerned pri­ marily w ith the optimisation of feedstock and mixture properties (especially coal particle size distribution, additive fo rmulations and solids content). The automated boiler house A pilot scale prep aration facility has been designed capable of either continuous or batch An increasing number of coal fired sites are production at a rate of 1- 2 tonne/ h. To reduce the virtually unmanned and work is in progress with size and cost of this facili ty, pulverised coal will be two manufacturers to develop and test improved used as the feedstock rather than coarser commer­ control systems which will combine the advan­ cial grades. The faci li ty consists of a storage silo tages of centralised remote control with the faci lity for the pulverised coal, a reception hopper, a tube for local manual control in the event of break­ mill, a mixer and associated slurry storage tanks. down. The plant is to be con structed during 1985.

Fifteen Coal and ash handling The continued improvement of coal and ash A containerisation scheme h as been installed handling is essential for increasing the amenity of and commissioned at Nestles, Ashbourne. This is coal burning and for making the best possible use based on a standard ISO container which is of sites where space is at a premium. off-loaded using a special framework wh ich lifts it Throughout the year there has been a substan­ clear of the lorry and then tips it to empty the coal tial commitment to consolidating principles and into a pneumatic handling facility. A number of practices already introduced. The CRE coal recep­ alternative coal reception devices are also at an tion and storage scheme continues to operate well advanced stage of investigation . These include the and monitoring has yielded much useful informa­ " Walking Floor" (a patented device in which tion , including the collection and disposal of water reciprocating bars arc used to move coal from one draining from coal stored in a silo for prolonged end of a reception platform to another), a wide belt periods and the detection and control of spon­ conveyor, and a device based on a knife edge ram taneous heating within silos. The latter is of w hich withdraws coal from a flatbed reception particular interest as silo fires (although infre­ paltform. These devices are to be installed at quent) have occurred at certain sites and monitor­ commercial sites for demonstration purposes. ing the CO and 02 concentration in the headspace A design code for the storage and reception of above the coal is providing a valuable insight into pulverised fueJ has been prepared and several this subject. hundred copies have been dis tributed. This was The stresses that occur at sil o walls continue to required because a number of small industrial be monitored but the external strain gauges on the users are considering buying and storing coal silo structure have been replaced by pressure pads already pulverised rather than following the usual set into the walls. practice of milling on site followed by immediate Further improvements have been made in the use. reliability of suction nozzle systems for handling Wet ash handling is seen as a viable alternative both singles and smalls coals. Two different types to the various pneumatic ash removal systems of discharge valve for separating the coal from the currently available and a hydraulic sluicing sys­ carrying air are currently being assessed. tem, developed at CRE, is being install ed for d emonstration purposes at a site in Yorkshire.

Jnstn/latio11 for hn11dli11g co11 tai11erised coal at Nestle Ltd, Asllbo11m e

,

Sixteen A dense phase, in­ cremental coal feeder developed in collabor­ ation with Sturtevant Ltd has been used to fire a 15 MW boiler. The feeder projects small 'slugs' of a con­ sistent size (adjust­ able in the range 1 - 2 kg) along a pipe for • distances up to 80 metres, and could be used to supply coal direct from a silo into a remote boiler or furnace.

Domestic and commercial heating Automated domestic coal-burning boilers The development of a range of appliances based Field trials of the 25, 38 and 50 kW stokers have on the self-cleaning underfeed stoker has been the continued successfully and models for approval principal activity over the past year. All the are under construction by the manufacturers appliances utilise the same combustion system, involved. The maker of the 30 kW Heat House, using selected bituminous singles supplied by a which includes a 2 tonne coal bunker and automa­ feed screw to a cast iron retort in which combus­ tic ash removal, has formed a new company to tion is completed with the ash and clinker falling produce and market the appliance. over automatically into the ash pit. The field trials of all these appliances have Assessment of 17.5 kW units from three manu­ continued to demonstrate that burning bitumi­ facturers has been completed and two of the nous singles efficiently in the self de-ashing retort companies, Worcester Engineering and Trianco, reduces running costs by some 50% compared have now submitted appliances for DSFAAS and with equivalent oil fired units. Also, high levels of Dept of Environment approval following success­ amenity can be achieved. ful field trials during the 1984/85 heating season. Both appliances use a 50 mm diameter centreless feed screw which reduces the size and cost of the appliance. The Worcester Engineering model, the Coal Stream, has been on display at the Ideal Home Exhibition and it will be launched in June/July 1985.

Seventeen Worcester Engineering 17.5 kW (60,000 Btulh) bo ile r "Con/ Stream" fired by n self-cleaning underfeed stoker

1

6 kW incremental feed home heater (warm air).

Appliance and systems development The pair of timber frame houses, built in collaboration with the Coal Merchants' Federa­ tion, were officiall y opened by Lord Avon in August 1984, and have been used extensively fo r the demonstration of soli d fuel systems for timbe'r framed houses to architects, heating engineers and local authority officers. They are also used for the development and testing of heating systems and a new increm entally fed appliance for use in conjunction with a warm air distribution system is currently being installed. This w ill allow complete automatic control of the house heating with attention by the householder only two or three times a week.

Eighteen Commercial heating The same underfeed stoker principle has been applied to units suitable for heating commercial premises, and a range of appliances between 50 and 300 kW, producing either hot water or hot air, are currently being developed. Two manufacturers are expecting to market 150 kW hot water models during 1985 following collaborative developments with CRE. These appliances will also be fitted with auto­ matic ash removal by a mechanical/ pneumatic system developed at CRE in which the ash and clinker from the retort fall first into a combined crushing/extraction screw. This reduces the top size of the clinker and withdraws the material to an external reservoir, from which it can be removed periodically by suction through an ash dump valve which drops it into a container or plastic bag for disposal. This system has been operated at a trial site for three months with complete success. A warm air version of the appliance was manufactured by James Scott Ltd during 1983/84 and was demonstrated both in the laboratory and at an exhibition site. This sh owed the need for a more efficient heat exchanger which is currently being developed. An assessment of a commercial ram-fed stoker, the "Autoburn", burning a mixture of washed smalls and coke, showed that the combustion intensity was locally very high, giving rise to hard clinker in the fire bed and grit emission from the chimney. An improved stoker has now been designed by CRE using the ram-feed principle but with radically different air distribution through the grate, a better coal feed system and an improved heat exchanger. This appliance will be used to determine the performance of bituminous 150 kW fully automatic commercial washed smalls as a fuel. boiler fired by a self-cleaning underfeed stoker.

Flue Cleaning Device

Vacuum Cleaner-

Door Mounted Retort

~ CRE

Nineteen Appliance testing Fuel testing There continues to be a high demand for testing The testing of smokeless and other fuels, for on behalf of the Domestic Solid Fuel Appliances various organisations, has been undertaken as Approval Scheme (DSFAAS). CRE, being the required. principal testing station, received 35 applications The work includes measurement of smoke and thermal performance testwork was completed emission from 12 types of experimental bri­ on 21 units during the year. quettes, from two candidate authorised fuels on The trend has been for more applications from behalf of the Department of the Environment, and new manufacturers with multi-fuel and imported from Homefire briquettes under various con­ appliances, and a revived interest in convector ditions of age and moisture content. To assist NSF open fires and independent boilers. In support, in the quality control of Homefire briquettes, CRE has assisted manufacturers to convert wood­ monthly measurements of smoke from production burning appliances to make them suitable for samples have also been carried out. mineraf smokeless-fuel burning. The physical and chemical characteristics and Examples of the new automated-boilers fired by thermal performance of Maxibrite, a Welsh self-cleaning underfeed s toke rs have been Anthracite-based ovoid briquette, have been received for DSFAAS performance and Dept of determined on behalf of NSF. Environment s moke approval. Contracts have been completed for the Depart­ As part of the Domestic Solid Fuel Appliances ment of the Environment and the Coal Merchants' Approval Scheme, CRE staff have visited 13 Federation involving the assessment of a number manufacturers' works and inspected some 50 of imported li gnite-based briquettes. appliance models to check on standards of quality An investigation has been carried out to assist control. NSF in establishing the optimum properties of A standard method of test for determining the domestic fuels. The work has involved the testing performance of wood-burning appliances up to of fuels recommended, in the DSF AAS list of 45 kW has been established in collaboration with approved appliances, as suitable for open fires, WARM (Wood and Solid Fuel Association of roomheaters and boilers. Retailers and Manufacturers). Formal testing for Other fuels examined included straw bri­ WARM began in August 1984 and, of the range of quettes, straw/coal briquettes, coal slurry pellets, 10 appliances examined during the year, 9 have Easiburn refuse-derived fuel pellets and logs gained WARM approval. made from waste coal, fat and paper. Further tests have been carried out, under CRE has continued to provide a s'ervicing and contract to the Domes tic Coal Consumers' replacement facility for radiometer cages and Council, to investigate the performance of two elements, and for electrostatic precipitators used representative open fires with high output back at the various other testing stations within the UK. boilers and one smoke-reducing roomheater, all burning a range of fuels at 100% and 50% rated output.

Trianco 17.5 kW (60,000 Btu!h) boiler fired by a self-cleaning underfeed stoker.

Tw enty l BAG FILTER

AIR _ FAN PRESSURISING COOLING WATER UNIT COOLER

Cloo/IOI FLARE Oiny Gas

SOLIDS FOR l CcolProcU:t DISPOSAL Gasanclfres l I I _ f Cold Clean &.s -.. Sl6>m t t VENTURI Ccld Wat SCRUBBER Ot•r/l.Jr OISPL l SLURRY ! sucnON NOZZLE FOR DISPOSAL FLUID BED GASIFICATION PILOT PLANT

Industrial gasifiers Studies have revealed a consid erable medium­ To reduce the cost of the process, the amount of term market potential for coal for a range of on-site coal prepa ration and handling has to be industrial energy users who need a source of reduced to a minimum, and the gasifier has now cheap gas. Developmen t of the NCB fluidi sed bed been modified to use uncrushed (singles) coal gasifier, coll aboration with other UK gasifier feed; this fuel is fed above the gasifier bed. The developers and manufacturers, and joint studies d esign of the gasifier base has been altered to with potential customers, are all being pursued to ensure good particle mixing within the bed, and penetrate this market. The intention is to provide sufficient testing h as now been completed to systems to complement the industrial combustion confirm that the lump coal can be used effectively. systems which are currently available or under A 12 tonne/day (coal feed) gasifi er has now been development. The specific aim is to provide constructed and commissioned at CRE, partly simple, flex ible gasifiers which will all ow coal to funded by the EEC. The gasifier allows lump coal be used wh ere clean environments, high process to be fed overbed, and the primary cyclone fines to temperatures and carefully controll ed conditions be recycled to the reactor. Th e plant incorporates are required - replacing oil, lpg or natural gas. systems to cool the product gas to 200°C, before The current work to develop an atmospheric­ final cleaning using a high efficiency cyclone in pressure air-blown fluidised bed gasifier is a combination with either a wet scrubber or bag continuation of the development of a 'partial' filter. A portion of the cleaned gas will be burnt in gasification system, in which crushed coal is fed a test gas furnace. This plant should make it pneumaticall y to the base of the gasifi er; this was possible to demonstrate all aspects of the process demonstrated in 1983 at a scale of 12 tonne/day a t a scale approaching that envisaged for com­ (coal feed) on a temporarily modified plant loaned mercial operations. by NCB Coal Products Ltd. Approximately 70% of Preli minary tests using an oxygen-enriched the coal was gasified, the inten tion being that by­ gasifying medium have been carried out. This product char would be burnt in an adjacent gives a significant increase in the calorific value of fluidised bed combustor in order to raise the product gas and the speci fi c throughput of the additional process heat or steam . The capability of gasifier, thereby extending the range of potential the NCB gasifier to process a wide range of UK applications. coals (up to a swelling number of 8) and to retai n During the year contacts have been mai ntai ned sulphur in the fluidised bed by the addition of a with other UK gasifier developers to ensure limestone sorbent was demonstrated. compatibility between their designs and the The aim now is to develop a 'total' gasifier in specification of UK coal supplies. In addition the which unreacted fine carbon particles elutriated experimental gasification work has been backed from the fluidised bed a re captured and recycled. with process modell in g studies, gas combusti on Following development of a reliable fines-recycle studies and engineering design /costing studies. d evice, extensive tests have now been comple ted in small-scale gasification equipment.

Twe11ty-011e Power generation The major market for coal is in power genera­ Off Gas tion; in order to retain this market (in the light of the growing contrib ution from n uclear power and possible restrictions on sulphur and nitrogen oxides emission to the atmosphere) it is necessary to have available technologies which use coal more efficiently and permit the economic control of emissions. In this context, it is of prime importance to develop pressurised fl uidised bed com bustion as the basis for a combined cycle power generation system incorporating both a gas turbine and a steam turbine. ~ Pressurised fluidised bed combustion .. The NCB and CEGB have agreed to finance jointly a £28 million programme of work on pressurised fluidised bed combustion. In pre­ paration for this work, eight specialist teams have been established on the various technical aspects of pressurised flu idised bed combustion, each team consisting of representatives from CRE, the Lock Hopper Grimethorpe PFBC Facility and the CEGB. The System teams have carried out reviews of existing infor­ mation and made proposals for test programmes using the facilities of th e participating organisa­ tions. These recommendat ions have been combined into an integrated programme of work in line with the available resources. The CRE part Cooling Tubes- of the programme will be centred on a 20 bar pressurised fluidised bed combustion facility. This facility h as been transferred from th e Coal ..- . Utilisation Research Laboratory at Leatherhead, where it was used mainly for contract work, and J ~1~ has been refurbis hed and reconstructed in a purpose-designed building at Stoke Orchard . To mini mise the manpower requ iremen t for ~~'O j ,,,Co~lfeed ...,., "' operation, extensive modifications have been made to the plant and a computer control system is being installed. Commissioning of plant com­ ponents has started, and hot commissioning is expected in June 1985. 20BAR PRESSURISED FLU ID BED COMBUSTOR AND CYCLONE Corrosion and erosion To ens ure reliable materials selection for full scale demon stration and commercial pla nts, studies to improve the understanding of corrosion behaviour within fluidised bed combustors have continued. This work has been partly funded by the US Electric Power Research Institute. Electro­ chemical probes have been used to monitor the oxygen partial pressure at the surface of tubes immersed in a fluid ised bed, for a ran ge of operating conditions. This information will be related to the corrosion of the tube materials under these conditions. Other aspects of the behaviour Gasification for power gen eration system s of materials which have been studied are the A combined cycle power generation system, corrosion of low chromium ferritic steels and the based upon gasification , has the potential for formation of deposits on in-bed tubes. ach ieving an overall cycle thermal efficiency above A m ajor cause for concern in the development of that at present feasible, once suitable gas turbines pressurised fluidised bed combustion is the high are developed. At the same time, very high rate of erosion of tubes within the bed which has environmental standards can be achieved by been observed at the Grimethorpe facility. Cold cleaning the gas prior to combustion. model studies have shown that the rate of erosion CRE has already developed a fl uidised bed can be reduced su bstantially by reducing the gasification system which has the potential to fluidising velocity to 0.8 m/s. T his finding has process a wide range of UK coals and to effect high been incorporated in the programme for future temperature desulphurisation by the addition of work at the Grimethorpe facility, and a new tube limestone to the fluidised bed. The present work bank is being manufactured for operation at is concentrati ng on the examination of hot gas 0.8 m/s. cleaning techniques for removing carbon/ash

Twenty-Two Part of th e operating floo r of the 20 bar pressurised fluidised bed combustor ready for co111111issio11i11g.

particulates and alkali metals. Based on p revious Equipment is now available to evaluate alkali successfu l small-scale studies, a test ri g has been sorbents at te mperatures up to 950°C. As an aid to commissioned and used to test silicon ca rb ide this programme, an alka li monitor fo r the detec­ filter ca ndles for the removal of particulates from tion of low levels of alkali metals in product gas product gas at 950°C. .In gen eral the tests have has been evaluated. However, this monitor, based shown that four ca ndles in parallel ca n operate on the principle of surface ionisation, has been over a long period with a high coll ection efficiency found to be subject to interference from other and a low residual pressure-drop. However there species in the product gas, and is not suitable in have been some problems with leakage across the its present form. More conve ntion al labour­ candle mountings, and modified designs are intensive techniques will be employed in the b e in g evaluated in conjunction w ith the current evaluation programme. manufacturer.

Twenty-Three Environment Waste utilisation Ash residues The NCB is firmly committed to minimising the Research aimed at assessing and minimising impact of coal utilisation on the environment. As a the environmental impact of the disposal of ash result, CRE carries out measurements of emissions residues has continued, and outlets for their arising from current coal utilisation technologies commercial utilisation are being sought. A large and research aimed at achieving improvements in number of residues produced from a wide range pollution control. It also examines the effect of of coal-fired boilers have been characterised in new coal utilisation technologies on the environ­ terms of their physical and chemical properties. ment, and investigates new and improved Samples of ash are being exposed to the methods for utilising the waste materials arising elements in order to establish their weathering from coal mining and utilisation. characteristics, while their leaching behaviour is being investigated in the laboratory. Results to Ahnospheric pollution date confirm that it is safe to dispose of coal ash In order to maintain an independent, well­ residues, although some care may be needed in informed position on the contribution of coal­ tif ping residues containing significant amounts derived emissions to atmospheric pollution, o spent limestone (used to capture sulphur in relevant literature is continuously reviewed and fluidised bed combustion boilers). Such residues discussions are held with many external organ­ will tend to give rise to relatively alkaline isations. This has enabled information and advice leachates but, on the other hand, after being to be provided within the NCB for dissemination tipped, they will harden naturally into a compact to outside bodies, including the House of Lords mass with reduced permeability to surface or and the House of Commons Select Committees ground waters. This self-hardening characteristic which have addressed the Acid Rain issue. Close is being examined further in order to determine links have also been maintained with the CEGB whether sulphated ashes can be used as cement throughout the year. replacement in stabilised road-base mixes. The With financial support from the NCB and the residues are also being investigated for use as CEGB, the Royal Society, in collaboration with the filler in asphalt applications. Swedish and Norwegian Academies, have com­ Encouraging results have been obtained from menced a 5-year study to establish factors which preliminary trials carried out at the North influence acidification of surface waters and to Staffordshire Polytechnic, in which ash from determine what benefits might follow from industrial fluidised bed boilers has been used in emission control on UK combustion plants. brickmaking. This has involved mixing Weald Another project, also being funded by the CEGB clay with sufficient ash to provide the required and the NCB together with the Scottish Electricity fuel content for the soft-mud brickmaking process. Boards, is centred at Loch Fleet in south-west The visual appearance and physical properties of Scotland, and is concerned with investigating the the fired bricks were satisfactory and a larger scale effect on the local flora and fauna of modifying the demonstration is now being planned. water chemistry of the loch by treatment of the Minestone loch water and the surrounding catchment area. Experimental investigations have continued in The emissions of S02, NOx, particulates and support of the Minestone Executive so that they trace elements have been determined on a number may maximise the utilisation of colliery waste in of stoker and fluidised bed boilers. The investi­ civil engineering applications. gation of the release of trace elements has identi­ The need to monitor embankments for tempera­ fied discrepancies in the mass balances for some ture continues, in order to reassure potential users components, which is a problem reported by other that the risk of spontaneous combustion of worl

Twenty-Four Coal Products Construction products TECHNICAL support has been provided to Several new products have been developed to a Thomas Ness Ltd, a wholly-owned subsidiary of stage where, if production and field trials are NCB (Coal Products) Ltd. This has included satisfactory, they can be added to the product innovations and developments for advancing range. These include a self-adhesive roofing their main fields of business: construction installation which eliminates the use of hot products, tar and chemical products. bitumen as the adhesive, and a Multiplas roofing sheet with improved properties which will pass the new stringent European s pecifications. Support has been given to the Hyload activity; this has included plant improvements, identifi­ cation of new feedstocks and assistance in obtaining European approval certificates, e.g. Agrement Suivi (Belgium).

Bench apparatus for testing th e resistance to leakage of joints in waterproof roofing systems

Chemical products

Several processes for treating solvents have RESINS MADE FROM THE BY- PRODUCTS OF COAL been developed. These include , a method for AND THEIR USES continuously dehydrating solvents which uses less energy than conventional processes, and methods for removing aromatics from kerosenes and gas oils. A number of improved non-toxic froth-flotation F><;'.').AlEll ~!S.'. \'l'J;',!:}i oils have been developed fo r cleaning both power lftt>.?'.AAi!C"I P[~'.S station and coking coals. Varieties of these have I been particularly effective with aged coals, and EfQX.OE ClllF.'1 li~:.;.;;.TES with Australian and Canadian coals. A prototype l AC"l:SW£S single phase hydraulic fluid is undergoing NCB S!Af-ACT (~T1ViS approval testing. ~·F?,'.l( • ~"'-P.:£.l Resins developed at CRE from aromatic feed­ l;{'.~JC(["('

Twenty-Five The chemical quali ty of the tars available to ANODE CONSUMPTION FURNACE Ness varies widely, so CRE has had to advise on the selection of treatments so that effective binders can be prepared for producing electrodes for use in the smelting industries. CRE had to find ways to predict the behaviour of these tars in practice, and to develop novel methods to enable a wide range of fecdstocks to be used. A model aluminium electrolyte cell has been built and commissioned; this enables the performance of electrodes usi ng different binders to be predicted. .. ' • • • • • • • • • • 0 Smokeless fuels Domestic coke In an effort to establish criteria fo r different sectors of the domestic heating market, assistance has been give n to NSF in the drafting of specificati ons fo r solid fuels suitable for open fires, roomheaters and domestic boilers. An investigation has started with the objective of A bubble-breaking device has been suggested matching the corn bustion performance of NSF­ by CRE as a possible means of obtaining better produced cokes to the respective appliance speci­ fluidisation in the H omefire carbonisers; the fications, and to provide a basis for comparison proposal is now being considered at the works. A with other premium smokeless fuels. new set of cyclones h as been installed in one of the reactors and its influence on the off-gas solids Phurnacite loadings is currently being determined by CRE. The use of sequential blending methods as a means of improving the dispersion of strongly Ancit caking components in Phurnacite-type feedstocks In preparation for the commissioning of the was examined on the pilot scale. Minor pro­ new Ancit plant in South Wales, it is important to portions of different coking coals were pre-mixed establish consistency between German and UK with part of the less reactive feedstock prior to test methods. One of the .vital tests for assessing final mixing. The resulting carbonised briquettes the suitability of the binder coal is the measure­ were of good physical quality and, as in earlier ment of dilati on characteristics, and progress has tests, the product was improved wh en the coarse been made in ensuring that resu lts obtained by material was eliminated from the feedstock. the German technique agree satisfactorily with Sequential b lending is now being used in those determined by the BS method at the NSF Phurnacite manufacture. and CRE laboratories. Microscopic examination and microstrength A procedure has been developed at CRE to testing of ca rbonised products, from feedstock simulate the Ancit process on the laboratory scale. coals and binder pitches typical of those used at The apparatus has been tested satisfactorily and the Phurnacite Works, have been done under testwork will commence shortly. contract at Newcastle University. The findings highlighted the importance of the selective inter­ Other briquetting processes action of pitches with various coals, the optimum Further tonnage quantities of pitch-bound blending of the pitches and the size distributions coal/iron ore briquettes were produced in the pilot of the coals. Briq uetting tests at CRE will now plant for assessment by BSC; the results were show w hether the micro-scale findings apply on again promising. At the laboratory scale, bri­ the 'single briquette' scale. quettes were made from a range of coals and binders, for tests by BSC in their direct reduction Home fire process. Efforts have continued to identify coals which, Assistance to British Gas Corporation has when added to conventional feedstock, are continued, concerning the upgrading of coal fines capable of improving the yield and physical for use in their gasifi er. quality of Homefire. So far, the most promising Pellets produced from jigged slurry and fil ter additive coals have been within the CRC 203 - 401 cake in a pilot plant operated by the Mining range with up to 5% benefit in solids yield, but Research & Development Es tab lishment were none of the bl ends tested so far has given tested a_t CRE ..In general, the pellets were strong simuJtaneous improvement in both product yield but their burning rate was low because of their and q uality. high ash content.

Twenty-Six Metallurgical coke High temperature properties An important requirement for coke used in cokes are still weakened by subsequent high modem l:ilast furnaces is that it should be highly temperature exposure in nitrogen alone, and it resistant to size degradation when exposed to the will be necessary in our future work to take severe mechanical, chemical and thermal con­ account of these effects when recommending ditions of the iron smelting process. In this blend formulations for alkali-resistant cokes. context, the major cause of coke weakening is now attributed to alkalis, which circulate in the furnace and deposit on the coke. Thus, attention is being focused on means of producing coke of improved Silica welding alkali resistance. . Over the past year research effort has con­ CRE's approach to the assessment of blast centrated on improving the throughput and furnace coke quality is to use, whenever possible, operation of the silica welding system which is bulk samples of cokes in the size grading normally used to repair the hot walls of coke-oven charged to blast furnaces, and to subject the chambers. A new patented machine, developed at samples to pertinent conditions of temperature CRE, has proved to be reliable in works trials and and chemical environment. Tests with a wide is now in commercial use. It is giving a marked range of commercial and pilot-oven cokes showed improvement in powder deposition rates without that the consecutive actions of impregnation with loss of weld quality. Further development work is potassium carbonate, and inert heating to 1000°C, in progress to achieve greater throughput, thereby gave rise to severe structural weakening at improving the profitability of the process. potassium concentrations above 1.5%. Surpris­ ingly, for a given concentration of potassium Coking blend formulation deposited, cokes made from prime coking coals Carbonisation tests have continued in the pilot exhibited relatively poor resistance to alkali attack. movable-wall oven with its specially instru­ However, separate small-scale experiments mented ram assembly. Modifications have been demonstrated that the rate of absorption of made to the equipment to permit higher pushing potassium vapour in such cokes was slower than forces to be applied to the captive coke mass, so as in cokes made from high~volatile coals. to simulate more closely the loads applied in In further bulk scale tests, both carbonaceous commercial ovens. and inorganic additives were included in oven Using this apparatus, it has been shown that at charges, an.d some improvement was achieved in least 40% of low rank coals (CRC 602-802), if they the initial and residual sizes of the cokes after have relatively low sulphur contents, may be alkali impregnation and reheating. Heating cokes incorporated in preheated blends used com­ to higher temperatures than experienced in their mercially to produce blast-furnace coke without manufacture (i.e. up to 1400/1450°C), before adversely affecting the strength of the product. A impregnation with alkali, improved the resistance number of imported coals oflow sulphur content of most of them to alkali attack. from USA, Canada and Australia, have also been Current studies are aimed at a closer simulation examined. Several of these coals were shown to of blast furnace conditions. This is necessary generate high wall pressures during carbonisa­ because carbon dioxide {which is present in the tion, and would probably cause pushing problems blast furnace) suppresses crack formation in in commercial ovens, particularly if used in the alkali-impregnated cokes. Nevertheless such preheated condition.

"Refrax" vessel

General arrangement of equipment for determining the bulk reactivity of blast furnace coke to C02. CD Thermocoufle The vesse charged with 25kg blast furnace coke is placed in a coke oven and heated by radiation from the walls.

Twenty-Seven Liquid Fuels & Chemical Feedstocks

Liquefaction Process development Equipment studies The design is proceeding of the 2.5 tonne/day Testing of filtration equipment and operation pilot liquefaction plant to be built at Point of Ayr have continued on the 0.5 tonne/day scale at CRE. colliery, North Wales, for the development of the Satisfactory filtrate clarity and cake retention, NCB liquid solvent extraction (LSE) process for washing, drying and discharge have been ob­ the conversion of coal to transport fuels. Designs tained with both vertical leaf and candle filters providing a budget price for the plant have been and a number of different filtration media. prepared in collaboration with Babcock Woodall­ These operations have also been studied in the Duckham Ltd, and detail design is proceeding, laboratory, in equipment which includes a with financial support from the EEC, leading to specially designed unit for long-term performance the preparation of tender documents for the monitoring. construction phase. During the year a number of process options Secondary processing have been investigated at CRE, using Point of Ayr Refining treatments have already been demon­ coal, to assist in the planning of the test pro­ strated for the conversion into gasoline and diesel gramme on the pilot plant. These investigations fuel of the primary distillates from the LSE nave been carried out in a unit incorporating process. A method has now been established for extraction, filtration, hydroprocessing and distil­ carrying out hydrogenation for the preparation of lation stages, with recovery and recycle of the automotive diesel fuel at a much lower pressure process solvent. Several runs have been performed than used previously. Improvements have also of up to 1600 hours operation and involving up to been made to the procedure for producing a 15 recycles of the solvent. Process streams were gasoline that meets anticipated environmental analysed daily to determine the hydrogen and requirements. mass transfer across each reactor, and mass bal­ ances were performed daily over each process Product characterisation stage to identify the product distribution . .Factors The development of improved analytical controlling the yield of light distillate product and methods for the structural characterisation of coal the quantity and quality of the recycle solvent liquefaction products has continued. Dehydro­ have been identified from these and earlier runs, genation, followed by chromatographic separa­ and are being incorporated in a mathematical tion, has enabled solvent components that are model of the process. Operation with a stable poor hydrogen donors in the LSE process to be yield pattern, recycle solvent composition and identified and measured by gas chromatography/ catalyst activity has been obtained, and the effect mass spectrometry and nuclear magnetic of changes in operating conditions has been resonance spectrometry. Detailed information on monitored. the nature of aromatic and aliphatic groups in coal extracts has been derived by a combination of nmr and chromatographic methods.

Pyrolysis (direct conversion) The pyrolysis of coal in hydrogen (hydro­ pyrolysis and hydropyrolysis in an attempt to pyrolysis) is being studied to identify possible improve conversions to liquid products. Initial routes to chemical feedstocks and liquid fuels. results show that the additives need to be of low The investigation of two-stage hydropyrolysis, volatility, to avoid their premature loss by flash in which primary tar vapours are passed over evaporation. 1H-nmr results indicate that the hydrotreating catalysts to produce distillates, has hydrogen rich additives are not significantly de­ continued. Conditions have been optimised at hydrogenated, but that their presence reduces the moderate pressures (up to 150 bar) using a Ni/Mo extent of tar polymerisation. catalyst when 30% w/w of the coal is converted to Detailed structural characterisation of primary a distillable liquid, 30% of which distils below · tars by nmr and other analytical techniques has 450 K (naphtha). given information on the cracking and polymeri­ Petroleum fractions with some hydrogen donor sation reactions that occur during coal pyrolysis. capacity are being investigated as additives in coal

Twenty-Eight ? ,,..----n·---_. Stanton Red croft thermal analyser fo r determin ing mineral matter decomposition and catalyst stability.

Chemical synthesis It has been established that the life of the Research contin ues into the use of rhodium aluminosilicate HTDZ-48 can be increased from 15 catalysts for the conversion of synthesis gas hours to at least 300 hours by the incorporation of (carbon monoxide + hydrogen ) to higher alcohols. a small quantity (<5%) of a cyclic olefin in the Investigations have been concentrated on the methanol feed stock. In parallel w ith this, a pro­ addition of secon dary catalyti call y active species cedure has been develop ed and tested whereby such as ruthenium or platinum to the rhodiu m, the high er-molecular-weight alkyl benzenes pro­ and on the effect of promoters to increase sel­ duced from methanol can be converted , over ectivities and yields of ethanol. Lanthanum oxide HTDZ-48, to a product which is mostly C9 and C10 p romoted titania -sup ported rhodium catalysts alkyl benzenes. Also, toluene (and methane) can were found to exhibit selectivities depen dent on be produced almost exclusively when a methanol/ metal particle size which influence rhodium­ water mixture is passed over HTDZ-48 at about p romoter interactions. The effects of platinum 350°C. ad dition were dependent upon rhodium :plati num Th e catalyst can be used effectively to catalyse atomic ratio. High ratios increased ethan ol and the disproportion ation of toluene and the iso­ h ydrocarbon fo rmation w hile low ratios increased m eri zati on of xylenes in a manner similar to that methanol formation as well. Lanthanum oxide of commercial acidic zeolites, such as Mob il ad dition to the bimetalli c catalyst led to further HZSM-5 an d H -Mordenite. selective increase in ethanol yields. Catalyst char­ A series of experiments have been carried out to acterisati on techniques, such as temperature demonstrate the feasibility of preparing HTDZ-48 programmed reduction, X- ray photoelectron on a semi-continuous basis. Samples of silica spectroscopy and gas chemisorption, have been xerogel, when treated w ith a solution of al­ used to correlate catalytic activity with physical uminium sec-butoxide inn-hexane, were found to and ch emical properties. retain similar amounts of aluminium. However, only m aterials prepared with butoxide solutions Ruthenium catalysts have been studied for the of a limited range of concentration were active selective fo rmation of low molecular weight catalytically. Further work has suggested that this alken es from synthesis gas. The n ature of th e m ay be due to a high er con centration of su pport h as been found to exhibit a profou n d aluminium in 4-coordination as compared to the influen ce upon prod uct selectivity. inactive materials.

Twen ty-Nine General Studies

Basic coal science: coal characterisation The chemical characterisation of coal is con­ The investigation into direct high-resolution cerned with the application of new chemical and 13 C nmr of coals and related solids has continued, spectroscopic procedures to the analysis of coals. in co-operation with scientists at the University of Particular emphasis is given to establishing the East Anglia. Although aromatic and aliphatic relationships between the chemical structures of carbon s ignals can be resolved, not all of the coal including associated minerals and the nature carbon is observed for coals. Factors responsible of fouling, corrosion and environmental pollutants for the loss of signal have been identified and encountered or produced in combustion and experiments have now yielded aromatic carbon conversion processes. values close to those calculated on the basis of In view of the problems arising from SOx and liquid extract studies. NOx formed during combustion, some attention Attention continu es to be given to h igh­ has been focused on investigating the chemical chlorine coals and the mode of occurrence of the environments of organic nitrogen and sulphur in chlorine. Aqueous leaching tests and surface coal. Two d istinct approaches have been used; the sorpti on studies on a range of coals have shown characterisation of mild solvent extracts and the that the ease of chlorine extraction is intimately direct spectroscopic examination of coals. Sulphur related to the pore-structure characteristics of the and nitrogen heteroatomic compounds present in coals. The effect of important param eters on the Point of Ayr coal have been successfully isolated rate and extent of dechlorination by low temper­ by subjecting mild solvent extracts to complex ature (<300°C) heating of coals in fixed and fractionation schemes. The fractions have been fluidised-bed laboratory rigs has been examined, characterised by qas chromatography, m ass spec­ and the kinetics of the release of chlorine as trometry, 1H and 3 C nmr spectroscopy, elemental hydrogen chloride have been d educed. Mass analysis and vapour phase osmometry. spectrometry on coals and their chlorine/chloride Modern structural analytical methods such as derivatives confi rms that all the chlorine in the Fourier transform infra-red spectroscopy are also coals examined is present as chloride ion. being used to study how salts and minerals are bound and how they behave during combusti on.

Nicolet SOX Fourier transform infra red spectrometer for studying th e structures of coal and coal-derived material.

Thi rty 0 ' "' .,r" .' RESS('"

LOSS J7

COAL FEED 100

Heat flow diagram for a conceptual power generation cycle combining a fast fluidised bed combustor, a gasifier and an advanced gas turbine.

Technical and economic studies A computer model of the LSE process is being developed which will be used to study both hydrotreating and hydrocracking option s in the p rocess configuration. This model will also be used in the planning and evaluation of the Computer modelling experimental work on the 2.5 tonne/day pilot p lant at Point of Ayr. The ARACHNE flowsheeting package has been Flowsheeting studies have been made of com­ used to investigate a number of complicated bined cycles for power generation based on fast­ power-generation cycle arrangements. Min or fluidised-bed combustion including supple­ improvements have been made to the flow­ mentary firing, and o n the British Gas sheeting package and the data base of the asso­ Corporation/Lurgi slagging gasifier. An evalua­ ciated IDMON costin g package has been tion was also carried out of the use of direct extended. Also, the ARACHNE system has been injection of limestone into pulverised-fuel adapted for use on a microcomputer. furnaces for conventional power generation. Liaison has been maintained with the CEGB and British Gas Corporation on power station design studies using a gasification combined cycle, an d with the CEGB on a design study for power generation based on pressurised-fluidised-bed combustion. A review and evaluation of Fischer-Tropsch synthesis technologies was completed as a major part of a study by Coal Processing Consultants of the use of indirect liquefaction technology in India. Contributions were also made to a CPC study on pressurised fluidised bed combustion for power generation in British Columbia. Assistance has been given to a team at MRDE who are planning a new development programme on underground gasification. AJreliminary spec­ ification for the above groun equipment has been prepared.

Thirty-One Combustion Systems Limited One of the ways in which accumulated R & D There are currently twelve CSL licensees, lo­ know-how relating to UK fluidised-bed combus­ cated in various countries, and during the year tion technology is introduced into the market equipment based on this UK technology has been place is through a CRE-based company, Combus­ ordered, or installed, in the USA, Japan , Peru, tion Systems Limited (CSL). CSL is the managing Italy, India, Korea, Turkey and Senegal. Also agency of a partnership between the National Coal engineers from Korea, India an d Turkey have Board and British Petroleum International pie set visited CSL for training in the design, installation up to exploit commercially the knowledge gained and operation of fbc plant. On-site assistance has from many years of research effort by these two been provided by CSL in commissioning the fi rst organizations. This work covers the combustion of commercial boiler in Japan, a 13 MW dual fuel unit prime and low grade coals and solid wastes by burning petroleum coke, w ith oil used for start-up NCB and the combustion of fu el oils, heavy and standby purposes. This boiler, along with petroleum residues and liquid waste materials by those built by the CSL licensee in USA, incorpo­ BP. Commercialization is achieved by licensing rates sulphur retention facilities in order to comp­ process design information to equipment manu­ ly with stringent local environmental standard s. facturers. There continues to be an increasing interest from many countries about the application of UK fbc technology, particularly for burning various types of medium and low grade coals and waste materials. Although enquiries to CSL predomi­ nantly relate to the use of solid fuel, there is also a requirement by many u sers to burn oil, using the BP-developed climbing-film nozzle system. Technical support available from NCB and BP enables CSL to respond to the many detailed queries concerning the design, operation and control of fbc plant. This includes computer-aided design on combustor details, the configuration of in-bed heat tran sfer surfaces and the prediction of performance when burning various types of low­ grade waste fuels. Also test facilities at the NCB and BP research establishments can be made available to licensees and collaborators to assist in assessing specific fu els and materials for future applications.

Fbc incinerator located near Rome, designed and installed under licence from CSL by Kinetics Tech nology In ternational

Fbc test and demonstration facility in Japan manufactured under licence from CSL by Hitachi Zosen

Thirty-Two Publications Papers Atkins, C. and Littlejohn, R.F. Some measurements Fisher, M.J. 20 years of fluidised combustion develop­ of trace elements in a grass dryer heated by a coal­ ment: a review. Paper to Xllth meeting on Flow fired fluidised-bed combustor. Energy in Agricul­ Through Porous Media, organised by the State ture, 1984, Vol. 3, No. 3, November, pp. 185-198. University of Maringa, held at Maringa-Parana, Brazil, 24--26 October 1984. 17pp. Bartle, K.D., Mulligan, M.J., Taylor, N., Martin, T.G. and Snape, C.E. Molecular mass calibration Foster, C. Coal and ash handling developments: an in size-excluswn chromatography of coal deriva­ overview. Paper to Solidex 84: a Solids Handling tives. Fuel, 1984, Vol. 63, No. 11, November, pp. Conference, Modern Technology in Bulk Solids 1556-1560. Handling, organised by Trinity Publishing (Conferences) Ltd, and Thames Polytechnic, Biffin, M., Syred, N. and Sage, P.W. Enhanced held at Harrogate, 16-18 April 1984. Paper Al, collection efficiency for cyclone dust separators. pp. A1-A6. Chemical Engineering Research and Design, 1984, Vol. 62, July, pp. 261-265. Fynes, G., James, R.G., Ladner, W.R. and Newman, J.O.H. Structural differences in the tars Carr, C.E. and Cooke, M.J. The preparation of and chars from the pyrolysis of coals of different mineral products by the heat treatment of coal rank in hydrogen and in nitrogen. Fuel, 1984, Vol. mining wastes. Paper to Symposium on the 63, No. 7, July, pp. 897-904. Reclamation, Treatment and Utilisation of Coal Mining Wastes, organised by the Minestone Gay, A.J., Littlejohn, R.F. and Van Duin, P.J. Executive of the National Coal Board, held at the Studies of carbonaceous cenospheres from fluidised University of Durham, 10--14 September 1984. bed combustors. 1983 conference publication Paper 39: pp. 39.1-39.22. reported last year, now published in Science of the Total Environment, 1984, Vol. 36, June lst, Clarke~ J.W. and Rantell, T.D. Filtration in coal pp. 239-246. liquefaction: part 1: influence of coal type. Fuel, I 1985, Vol. 64, No. 3, March, pp. 351-357. Gray, M.D. and Thurlow, G.G. The NCB's liquid solvent extraction project. Paper to Coal Tech­ Clarke, J.W. and Rantell, T.D. Filtration in coal nology Europe '84: 4th European Coal Utilisa­ liquefaction: part 2: relationship between digestion tion conference, organised by the Industrial conditions and filtration rate. Fuel, 1985, Vol. 64, Presentations Group, Schiedam, The Nether­ No. 3, March, pp. 358-363. lands, held at Messe, Essen, Federal Republic of Germany, 4--6September1984. Vol. 3, pp. 87-99. Clarke, J.W., Rantell, T.D. and Snape, C.E. Reac­ tivity of cycloalkenes during the solvent extraction Green, R.C., Paterson, N.P. and Summerfield, l.R. of coal. Fuel, 1984, Vol. 63, No. 10, October, pp. Demonstration of fluidised bed gasification for 1476-1478. Poster paper to Fuel Science, Gordon industrial applications. Energy World, 1984, No. Research Conference, held at New Hampton, 116, July, pp. 7-10. New Hampshire, USA, 1-6 July 1984. Herod, A.A., Hodses, N.J. and Stokes, B.J. Mild Clarke, J.W. and Rantell, T.D. Solids separation from pyrolysis of coal in an inert atmosphere. Paper to the products of the solvent extraction of coal. 14th Meeting of the British Mass Spectrometry Powder Technology, 1984, Vol. 40, October/ Society, held at the Heriot-Watt University, December, pp. 223-234. Edinburgh, 18-21 September 1984. (slide pre­ sentation - abstract available from CRE library). Dainton, A.O. Coal utilisation in the UK: problems and prospects. Robens Coal Science Lecture, held Herod, A.A. and Smith, C.A. Release of oxygen and at the Royal Institution, October 1984; pub­ sulphur compounds from coal. Fuel, 1984, Vol. 64, lished in Energy World, 1984, No. 120, No. 2, February, pp. 281-283. December, pp. 2-11. Hoy, H.R. and McKendrick, D. Power generation Davidson, B.J., Holmes, J. and Merrick, D. via combined cycle power plant burning coal in A comparison of combined power generation cycles pressurised fluidised bed combustion systems

Thirty-Three Kimber, G.M., Whitehead, J.C., Cain, M., Rogers, E.A. and Cooke, M.J. The recovery of Mukerjee, A. and Hildebrandt, R.D. Production energy from coal mining waste by fluidised bed of reduction grade coke from low ash Buller coal. combustion. Paper to Symposium on the Re­ Paper to Carbon '84: International Conference clamation, Treatment and Utilisation of Coal on Carbon, organised by the Centre de Mining Wastes, organised by the Minestone Recherche, Paul Pascal Domaine Universitaire, Executive of the National Coal Board, held at the and others, held at Bordeaux, 2-6 July 1984. University of Durham, 10-14 September 1984. lOpp. Paper 37: pp. 37.1-37.13. Ladner, W.R. The state of combination of chlorine in Rowlandson, B. and Topper, J.M. Factors to be coal. Fuel, 1984, Vol. 63, No. 5, May, p. 726. considered when storing pulverised fuel for indus­ trial use. Paper to the Prevention and Control of Littlejohn, R.F. Emission of trace elements from coal­ Dust Explosions: a seminar organised by the fired industrial boilers. A survey of relevant Institution of Mechanical Engineers, held at literature. International Journal of Energy Winnington Hall, Northwich, Cheshire, 14 Research, 1984, Vol. 8, No. 4, October/ November 1984. 4pp. December, pp. 375-386. Saunders, S.R.J., Hossain, K.M.K., Kent, B. and Marks, W.L. Fluidisation: gas-solids contacting and Lloyd, D.M. The sulphidation of alloys used in a bed expansion. Fuel, 1985, Vol. 64, No. 1, January, fluidised bed combustor. High Temperature Tech­ pp. 71-74. nology, 1984, Vol. 2, No. 2, May, pp. 63-73. Merrick, D. Mathematical modelling of the coking Snape, C.E. and Bartle, K.D. Definition of fossil fuel­ process. Paper to 43rd Ironmaking Conference, derived asphaltenes in terms of average structural organised by the American Institute of Mining, properties. Fuel, 1984, Vol. 63, No. 7, July, pp. Metallurgical and Petroleum Engineers (AIME), 883-888. held at Chicago, April 1984. 25 pp. Snape, C.E., Ladner, W.R. and Bartle, K.D. Fate of Minchener, A.J., Mainhardt, P.J., Mountford, R.A., aliphatic groups in low-rank coals during extrac­ Erbe, G., Anderson, J.S. and Mccarron, R.L. !EA tion and fyrolysis processes. Paper to Society of Grimethorpe 2 x 2 m pfbc facility; turbine Chemica Industry conference on Structure and materials testing in a cascade loop. Paper to Reactivity of Coals, held in London, 25-27 International Gas Turbine Conference, organ­ March 1985. 12 pp. To be published in Fuel, ised by the American Society of Mechanical 1985. Engineers, held at Amsterdam, April 1984. ASME paper No. 84-GT-291. 21pp. Snape, C.E. and Bartle, K.D. Further information on defining asphaltenes in terms of average structural Moodie, J. and Vickers, M.A. Some heat and mass properties. Fuel, 1985, Vol. 64, No. 3, March, pp. transfer considerations in the design of fluidised bed 427-429. boilers. 8th International Symposium on Che­ mical Reaction Engineering, organised by the Snape, C.E., Ladner, W.R., Bartle, K.D. and Taylor, Institution of Chemical Engineers, held at N. Improvements in the structural analysis of Edinburgh, 10-13 September 1984. IChemE asphaltenes. Paper to International Symposium Symposium Series No. 87, pp. 45-51. on Characterisation of Heavy Crude Oils and Petroleum Residues: organised by the Institute Newman, J.O.H. New developments in obtaining Frani;ais du Petrole, held at Lyon, 25-27 June chemicals from coal by pyrolysis. The second 1984. pp. 315-321. paper in Chemicals from coal: new develop­ ments; edited by K.R. Payne. To be published Snape, C.E. Structural analysis of high molecular for the Society of Chemical Industry, by weight fossil fuel derived materials. Paper to Fuel Blackwell Scientific Publications, 1985. SCI Science, Gordon Research Conference, held at Series Critical Reports on Applied Chemistry, New Hampton, New Hampshire, USA, 1-6 July Vol. 9. pp. 68-97. 1984. (No text available for Gordon Conference reports). Payne, R.C. and Lake, J.M. Self cleaning underfeed stokers for the domestic market. Build News, 1984, Stringer, J. and Minchener, A.J. High temperature Autumn, p. 2. corrosion in fluidised bed combustion systems. Paper to High Temperature Corrosion in Energy Pillai, K.K. Off-design performance of combined Systems, organised by the Metallurgical Society cycle power plant utilising pressurised fluidised bed of the American Institute of Mining, Metallur­ coal combustors. Paper to 4th International Con­ gical and Petroleum Engineers, and the ference on Energy Options: the Role of Alter­ Materials Science Division of the American natives in the World Energy Scene, organised Society for Metals, held at Detroit, Michigan, by the Institution of Electrical Engineers, held at USA, 17-19 September 1984. Paper no. LBL- the IEE, London, 3-6 April 1984. Published as 18312. 25 pp. IEE Conference Publication No. 233, pp. 266-269. Taylor, N., Gibson, C., Bartle, K.D., Mills, D.G. and Richards, D.G. Electrochemical oxidation of Richards, D.G. Synthesis/as conversion to alcohols. coals; voltammetry and mass spectrometry. Fuel, Paper to Chemical an Physical Valorisation of 1985, Vol. 64, No. 3, March, pp. 415-419. Coal, a Round Table meeting of the European Coal and Steel Community, held in Brussels, Thurlow, G.G. From development to exploitation: 7 December 1984. 17 pp. case histories of the fate of some coal utilisation R & D projects. Energy World, 1984, No. 119, November, pp. 2-13. Thirty-Four Thurlow, G.G. and Williams, D.F. Recent Northcote, R.D., Milner, C.N., Payne, R.C. and developments of the LSE process for producing Peirce, T.J. Development of fluidised bed fire­ gasoline from coal and lignite. Pafer to Energex tube boilers. pp. KN/IA/3/1-8. '84: Canada's 2nd Internationa Energy Con­ ference, sponsored by Saskatchewan and Pagett, C., Moore, J.P. and Fisher, M.J. Op­ Regina, held at the University of Regina, 14-19 erational experience with a Wallsend open­ May 1984. 5 pp. hearth 1.5 MW fully automatic fluidised bed boiler. pp. DISC/8/57-64. Topper, J.M. The influence of new technology in support of expanding industrial coal sales. Based Pillai, K.K. and Nilsson, J. Direct injection of coal on a lecture given to the Institution of Mining water paste (cwp) into pfbc's for combined cycle Electrical and Mining Mechanical Engineers, power plant. pp. DISC/40/359-365. North of England Branch, meeting held at Houghton-le- Spring, 6 November 1984. 11 pp. Read, D.C. and Minchener, A.J. The low (Text available from CRE library). temperature combustion characteristics of various coals in a fluidised bed combustor. pp. Tringham, D. The industrial use of coal. Summary DISC/26/224-231. only of the Address to the Energy Managers Group of Humberside, held at the Humberside Sage, P.W., Wright, M.A. and Clark, R.K. College of Higher Education, 21 April 1983. Particulate removal developments for industrial 4pp. coal-fired fluidised bed boilers. pp. DISC/43/ 397-407. Papers presented to: Stringer, J. and Minchener, A.J. Materials issues Fluidised Combustion: is it Achieving its in the development of fluidised bed combustion. Promise? Conference organised by the Institute of pp. DISC/29/255-274. Energy, held at the Hilton International, London, 16-17 October 1984. Volumes I and II. Windybank, A.R., Smith, T.N., Laws, W.R. and Reed, G.R. Production evaluation of the Butt, AR., Payne, R.C. and Peirce, T.J. The Peabody Encomech coal fired clean air heater. seneration of high temperature gas from fluid­ pp. DISC/15/121-133. ised bed furnaces. pp. DISC/5/35-42. Papers presented to: Chakraborty, R.K. and Vickers, M.A. Heat transfer characteristics of cooling tubes in the expanded and splash regions of a fluidised bed Eighth International Conference on Fluidised Bed pp. DISC/33/292-298. Combustion, sponsored by the US Department of combustor. Energy, Electric Power Research Institute and the Cooke, M.J. Key aspects of fluidised combustion: Tennessee Valley Authority, held at Houston, rapporteur's report for Session V: Environ­ Texas, 18-21 March 1985. mental. 6 pp. (not in published version: avail­ Bense, P.A. and Topper, J.M. Modelling and able from CRE library). experience of large diameter in-bed coils in a Cooke, M.J., Rogers, E.A., Dando, R.L. and once-through boi[er. 8 pp. Gauld, D.W. Ash management in the fluidised bed combustion of coal. pp. DISC/27/232- 240. Butt, A.R. and Peirce, T.J. The generation of high temperature gas from fluidised bed furnaces. Davenport, A., Struthers, J., Tringham, D.J. and lOpp. Peirce, T.J. Operating experience with Babcock 'Fluidburn' range of coal-fired fluidised bed Ellis, F., Stockdale, W., Tringham, D.J. and boilers. pp. KN/IA/2/1-8. Willis, D.M. Operating experience with Gibson Wells modular water tube boilers. 12 pp. Golden, R., Worsley, W.G., Payne, R.C. and Windybank, AR. Coal fired fluidised bed Fisher, M.J., Topper, J.M. and Jenkins, F. Some furnaces for direct hot gas drying and process new developments in fluidised bed shell boilers. applications. pp. KN/III/1-1 to 1-7. 13 pp. Highley, J. Flexibility and control in fluidised bed Lawton, J., Dainton, A.O. and Dawes, S.G. The combustion. 5 pp. (not in published version: CEGB/NCB programme on pfbc. 11 pp. available from CRE library). Minchener, A.J., Read, D.C., Sutcliffe, P.T. and Hoy, H.R. and Roberts, A.G. Pressurised fluidised Stringer, J. The use of solid state electrochemical bed combustion: past, present and future: an probes for characterisation of fluidised bed overview. pp. DISC/13/95-109. environments. 16 pp. Milner, C.N., Peirce, T.J. and Dawes, A.G. Minchener, A.J., Stringer, J., Brooks, S., Lloyd,· Develorment of a prototype fluidised bed D.M., Swift, W.M., Anderson, J.S. and therma fluid heater. pp. KN/III/2/1-8. Mainhardt, P.J. Materials studies at the /EA Grimethorpe pfbc experimental facility. 12 pp. Minchener, A.J., Read, D.C. and Stringer, J. Characterisation of the fluidised bed environ­ Parkinson, M.J., Napier, B.A., Jury, A.W. and ment by means of electrochemical probes. pp. Kempton, T.J. Cold model studies of pfbc tube DISC/20/166-182. erosion. Paper reference no. 9.3.

Thirty-Five Stringer,. J., Mccarron, R., Beltran, A.M., Papers published in: Minchener, A.J ., Anderson, J .S., and Mountford, R.A. Results from the turbine British Coal International: International guide to materials testing program on the IEA Grime­ UK coal technology and equipment, 1984. thorpe experimental pfbc facility. 22 pp. Cooke, M.J. Ash disposal and utilisation. pp. 491, Tringham, D.J., Peirce, T.J., Davenport, A. and 493, 495. Struthers, J.S. Operating experience with Babcock 'Fluidburn' fluidised bed boilers. 16 pp. Cooke, M.J. Combustion of low-grade fuels. pp. 486-488. Papers presented to: Gill, D.W. Environmental control technology. pp. 497-499. Technology of Coal Reception and Storage, organ­ ised by the NCB Coal Research Establishment, Gill, D.W. Environmental legislation in the UK. held at the Golden Valley Hotel, Cheltenham, 6 pp. 500-501. November 1984. Highley, J. Developments in coal, oil and water Crowther, M.E. Control systems and logistics for mixtures. pp. 466-467. coal storage. 7 pp. Highley, J. Industrial fluidised bed boilers. pp. Foster, C. On-site coal reception. 6 pp. 429-434. McLaren, R.W. Bunker and hopper discharge Highley, J. Oil/coal conversion. p. 468. aids. 8 pp. Ladner, W.R. Liquefaction technology. pp. 483- Rowlandson, B. Silos for coal storage. 11 pp. 484. Merrick, D. Combined cycle steam and power systems. pp. 464-465. Robson, B. Gas from coal. pp. 474-478. Williams, D.F. Transport fuels from coal. pp. 480-482. Willis, D.M. Energy in combustion. p. 445.

Patents McCaffrey, D.J.A., Removal of ethanol from organic Robinson, J.G., Barnes, D.I. & Riemer, P.W.F., mixtures, BP 2,127,011 A (4.4.84). Protonised aluminosilicate catalysts, BP 2,132,595 Stephens, P.J., Bed level control system for solid fuel A (11.7.84). appliances, BP 2,128,776 A (2.5.84). Robinson, J.G. & Barnes, D.I., ZSM-5 Preparation I Napier, B.A., Cooke, M.J. & Stayte, M.R., Fluidised & II, BP 2,132,993 A (18.7.84). bed combustion - control grating, BP 2,128,895 A Napier, B.A., Fluidised bed material classification, BP (10.5.84). 2,133,716 A (1.8.84). Clarke, J.W., Rantell, T.D. & Kimber, G.M., Jury, A.W. and Milner, C.N., Hot gas cleaning for Monitoring donor solvent, BP 2,130,366 A fluidised bed boilers, BP 2,134,813 A (22.8.84). . (31.5.84). McCaffrey, D.J.A. & Wilson, J., Solvent regeneration Finn, M.J. & Hughes, R.D. Staged temperature of molecular sieves, BP 2,135,661 A (5.9.84). coking coal, BP 2,130,599 A (16.6.84). Sage, P.W. Hitchman, A.F. & Ellis, A., Cyclone Dando, R.L., Fluidised bed-particle classification separation air bleed arrangement, BP 2,136,325 A system, BP 2,132,500 A (11.7.84). (19.9.84). Corrections to list published in 1983/84 Annual Dando, R.L. & Napier, B.A., External air classifier, Report- bed regrading system, BP 2,143,148 A (6.2.85). Self-cleaning rotary coal feeder BP 2,106,063 A (7.4.83) incorrectly ascribed to Milner, C.H. and Tate, P. - Should be Miller, C.H. and Tate, P. Ammonia treatment of coal BP 2,106,934 A (20.4.83) incorrectly ascribed to Pitt, G.J. - Should be Jayasinghe, S.S., Hooker, M.A. & Spencer, D.H.T.

Thirty-Six