EQUIPMENT DESIGNS Equipment designs and manufacturing drawings are offered for a range of sugar processing equipment as detailed below: x Shredders / Cane Knives – Heavy Duty x Diffusers (Cane and Bagasse) x Juice Heaters x Vapour Heaters (Direct Contact type) x Evaporators x Kestner type x Robert type x Entrainment Separators (Vertical Chevron – Internal & External) x Condensers for Evaporators & Pans (Internal & External) x Batch Vacuum Pans & Stirrers x Continuous Vacuum Pans x Vertical Crystallisers x Massecuite Reheaters x Remelters x Sugar Driers x Sugar Refining Equipment x Direct White Sugar process x Rotary Distribution System x Fluegas Scrubbers x Miscellaneous Equipment Tongaat Hulett Sugar Equipment Designs Shredders / Cane Knives (Heavy Duty) The Tongaat Hulett heavy duty shredder is a robust swing hammer pulveriser. The design incorporates high operating efficiency, low maintenance costs and resistance to damage in service. The patented rotor design gives overlapping coverage of the full shredder width with reversible swing hammers. The shredders have been installed worldwide for the last 25 years and are reliable and proven. The rupturing of the cane cells by the shredder leads to high extractions being obtained in both milling trains and diffusers. Cane & Bagasse Diffusers The Tongaat Hulett Diffuser is a variant of the moving bed diffuser. The basic design is a counter current contactor where juice is pumped (with a high percentage of recycle) onto a moving bed of prepared cane between 1.5 and 1.8 meters deep contained in a vessel approximately 60 meters long and divided into 10 to 14 stages. Typically the diffuser would have a working width between 6 and 12 meters. The prepared cane entering the diffuser is heated by juice which has been raised to a high temperature in juice heaters giving an average temperature in the diffuser of 85°C. The cane bed is moved across the top of a fixed screen by a series of chains with slats between them. The bed is prevented from blinding with fines and over-compaction by sets of patented lifting screws which break up the bed at two points in the diffuser. The bagasse is dewatered by one or two dewatering mills after exiting the diffuser. The diffuser at Komati Each diffuser is individually designed to suit the conditions and process specifications that the customer has supplied. Extraction can be as high as 98.5% if high imbibition rates are used with well prepared cane, but if a lower figure is all that is required then the diffuser size and imbibition rates can be reduced accordingly. Extensive use is made of 3CR12 in the construction of the diffuser to prevent corrosion and in addition a controlled liming system can be specified to control the juice pH to ±7. There are currently eight Tongaat Hulett diffusers in operation. Six in South Africa; at Felixton (2), Amatikulu, Maidstone and Komati (2), one in Kenya at Mumias and one in Louisiana, USA at Enterprise. Two more are under construction for commissioning in 2007, one at Savannah in Mauritius and the other at the new Skeldon factory in Guyana and a third is in the design phase for Bharat in India. One of the major advantages of selecting diffusion is the ability to recycle mud from the clarifier, thereby removing the need for a filter station. Mud recycle is used at all Tongaat Hulett’s South African sugar mills that use diffusers. A number of papers on the performances and advantages of the TH diffusers have been written and presented at various national and international conferences. A list and details of the TH diffusers supplied to customers since 1984 is shown below:- TH Designed Diffuser Installations Capacity Width Number Date Country Mill TCH m of Stages Installed South Africa Amatikulu 12 14 South Africa Felixton 600 x 2 12 12 1982/83 South Africa Komati 225 6,5 12 1993 South Africa Maidstone 300 9 12 1995 South Africa Komati 225 6,5 12 1998 Kenya Mumias 300 9 12 1997 USA Enterprise 300 9 12 1999 Mauritius Savannah 350 9 12 2007 * Guyana Skeldon 350 9 12 2007 * India Bharat 250 6.5 12 2008 * * Planned commissioning year Juice Heaters Tongaat Hulett offer the design of vertical shell and tube heat exchangers for heating raw and/or clarified juices to achieve the necessary process stream temperatures and for heat recovery throughout the factory, making use of low grade vapour, evaporator vapour and condensate streams. The designs can be optimized in terms of pressure drop (pumping requirements), heat recovery and size to meet required heat balance targets. Tongaat Hulett also have the capability and expertise to perform a pinch technology analysis to identify the optimal heat recovery layout as an additional process design service. Hippo Valley Mixed Juice Heaters Vapour Heaters (Direct Contact Type) Tongaat Hulett offer the design of direct contact vapour heaters which allow the possibility of using lower grade vapour for heating various liquid streams, thereby increasing the steam economy of the factory. Press Water Heater (Malelane) A list of TH design vapour heaters supplied to clients over recent years is given below:- Tongaat Hulett Designed Vapour Heater Installations Mill Service Diameter Date of mm Intallation Amatikulu Press Water Heater 1454 1984 Malelane Press Water Heater 2100 1998 Pongola Primary Mixed Juice 2180 1998 Savola Heater 2005 Carbonatation Heater Evaporators Tongaat Hulett TEG are experienced in designing both long tube climbing film (Kestner type) and Robert type evaporators complemented by the design of very efficient vertical chevron entrainment separators. Expertise in both steam chest design (in particular the removal of incondensable gases) and juice/syrup feeding and distribution, ensures optimal performance and maximum heat transfer coefficients. In addition, our multiple effect evaporator design procedure employs process models to distribute heating surface area between the effects most efficiently and can be used for the specification of the entire evaporator station, including all associated condensate receivers and flash vessels. Kestner Evaporator & Robert Evaporator at Separator at Malelane Si A list of the TH designed Kestner and Robert evaporators which have been supplied to customers since 1993 is shown below Kestner Type Unit Size Mill Heat Transfer Area Date of m2 Installation Felixton 4 x 5800 1985 Komati 2 x 3800 1993 Triangle/Zimbabwe 2 x 3100 1996 Umfolozi 1 x 3500 1997 Malelane 1 x 1000 1998 Komati 2 x 3800 1998 Hippo Valley-Zimbabwe 1 x 5800 1999 Robert Type Unit Size Mill Heat Transfer Area Date of Installation m2 Felixton 2 x 1430 1985 Felixton 4 x 1000 1985 Komati 2 x 1000 1993 Triangle/Zimbabwe 1 x 2000 1994 Felixton 1 x 1430 1996 Komati 1 x 2000 1998 Komati 1 x 1000 1998 Simunye 3 x 2200 1998 Xinavane/Mozambique 1 x 2000 2000 Mhlume 3 x 270 2002 Entrainment Separators Tongaat Hulett provide a very successful design of entrainment separator that is suitable for installation in batch pans, continuous pans, evaporators and separator vessels. The design incorporates vertical chevron plates that disengage the liquid particles by repeated changes in vapour direction and impingement against the plates. The entrapped liquid is drained back into the vessel. The design is in a modular form with easy access to the chevron plates by hinged sides. This allows rapid cleaning of the separator module if necessary. The number and configuration of the separator modules is defined by the evaporation rate, disengagement height and diameter of the vessel in which they are to be installed. Under steady operating conditions which meet the design specifications an entrainment level below 20 ppm can be expected and pressure drops across the separators will be less than 5mm water gauge. This design of separator is included in all the Tongaat Hulett designs of pans and evaporators and has also been very successful as a “retro-fit” to existing vessels with entrainment problems. Vertical Chevron Plate (VCP) Entrainment Separator being installed Condensers (Internal & External) for Evaporators & Pans Tongaat Hulett offer the design of efficient disc and doughnut “rain tray” type condensers for both internal fitment or external installation to a final effect evaporators, continuous vacuum pans or batch vacuum pans. The condensers are designed to operate on an approach temperature of ± 3°C. TH Designed Internal Tongaat Hulett Raintray Condenser Condenser Installation (Komati) A list of both internal and external Tongaat Hulett condenser designs which have been supplied to clients and installed since 1993 are shown below:- External Condensers Size Diameter Duty Date of Mill mm Installation Maidstone 1840 C-Cont Pan 1994 Pongola 910 C-Cont Pan 1995 Felixton 2250 5th Effect 1996 Clewiston – USA 1500 W- Batch Pan 1996 Maidstone 1250 Batch Pan 1994 Pongola 1800 A-Cont Pan 1998 Simunye – Swaziland 1300 C-Cont Pan 1999 Entumeni 3 x 1100 Batch Pans 2000 Xinavane – Mozambique 3 x 3200 Batch Pans 2000 Xinavane – Mozambique 2 x 1820 Batch Pans 2000 Xinavane – Mozambique 1200 5th Effect 2000 Mhlume – Swaziland 590 Final Effect 2001 Internal Condensers Size Diameter Duty Date of Mill mm Installation Simunye – Swaziland 1800 A-Batch Pan 1991 Maidstone 2 x 1700 Final Effect 1991 Triangle – Zimbabwe 1170 C-Cont Pan 1993 Komati 2 x 1026 B/C Cont Pan 1993 Komati 1520 A Cont Pan 1993 Komati 2 x 1472 A/B/C/ Seed 1993 Komati 1624 Final Effect 1993 Ubombo – Swaziland 1340 B-Cont Pan 1994 Triangle – Zimbabwe 2050 Final Effect 1994 Triangle – Zimbabwe 1250 B-Cont Pan 1994 Triangle – Zimbabwe 2000 A-Cont Pan 1995 Darnall 1130 B-Cont Pan 1995 Komati 1800 A-Cont Pan 1998 Komati 2280 A-Batch Pan 1998 Komati 1500 B-Cont Pan 1998 Komati 2000 Final Effect 1998 Batch Vacuum Pans & Stirrers Tongaat Hulett designed batch pans are conventional vertical tube calandria pans with a central downtake, which have been designed for A,B and C massecuites and refined massecuites.