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HIGH QUALITY TRANSPORTATION FUELS FROM RENEWABLE FEEDSTOCK

Lars Peter Lindfors Neste Oil Corporation ,

XXI st World Energy Congress Montreal, Canada September 12-16, 2010

ABSTRACT

Hydrotreating of vegetable oils is an advanced process for producing high quality renewable diesel fuels. Hydrotreated vegetable oils (HVO) are paraffinic similar to gas-to- liquids (GTL) and biomass-to-liquids (BTL) diesel fuels. They are free of aromatics and sulfur and have high cetane numbers. HVO is known as Renewable Diesel (RD) in the .

HVO can be used as blending component in or as pure fuel. When used as fuel on its own, significant reductions in NO x and particulate emissions can be seen. Thus, HVO is very suitable as diesel fuel for urban traffic like city buses. HVO processes can also be modified to produce jet fuel. Greenhouse gas (GHG) savings by HVO use are significant compared to fossil fuels.

HVO is already in commercial scale production. Neste Oil is producing its renewable diesel, NExBTL TM in two production plants. The emission performance and vehicle compatibility has been verified with extensive fleet tests and measurements. Production of will be limited by the availability of sustainable feedstock. Therefore research and development efforts are made to expand the feedstock base further. Additional technological routes for processing biomass into high quality transportation fuels will also be needed in order to meet future demand.

1. INTRODUCTION

It is evident that climate change mitigation requires action in all sectors including transportation. Inclusion of renewable components into fuels is an effective way to reduce GHG emissions. Several countries have already introduced legislation targeting or mandating certain content in transportation fuels. The other fuel properties, however, must not be overlooked. There should be no need to compromise on fuel quality while responding to the challenges set by climate change. There are products already now in the marketplace meeting the needs to reduce GHG emissions and to improve fuel quality at the same time.

1.1 General fuel quality views

Vehicle owners in the developed countries have had the privilege of using high quality fuels: ash free fuels with ultra-low or zero sulfur content and practically free of heavy fractions. For engines and exhaust emission control systems this has resulted in longer life times, fewer repairs, less maintenance and extended oil change intervals compared to the situation a decade or more ago.

In addition to the fuel specifications set by legislation and fuel standards, “fit for purpose” has risen as an essential requirement. Because of this, the use of certain bio components is opposed as they are seen to reduce fuel quality causing problems with engine cleanliness, engine oil compatibility, emission control systems, regulated or unregulated emissions and cold operability. Fuel requirements are in fact becoming more stringent due to new regulations for exhaust emissions, fuel economy, and on-board diagnostics. The mileage requirements for exhaust after-treatment systems are also being extended.

Fuel distributors have to take the storage stability and water tolerance into consideration when introducing into the fuel logistics and retail markets. Dedicated solutions that are not compatible with the existing fuel logistics involve significant extra costs.

1.2 HVO – Hydrotreated Vegetable Oils

Hydrotreating of vegetable oils is a novel way to produce very high quality biobased diesel fuels without compromising fuel properties. Current engines, exhaust after-treatment devices, exhaust emissions or fuel logistics can all be used without modification. HVO fuels are also referred to as “renewable diesel” instead of “” which as a term is usually reserved for the fatty acid methyl esters (FAME), Figure 1. Biodiesel NExBTL GTL FAME / RME renewable Fischer-Tropsch Fossil diesel diesel

Vegetable oils & Feedstock Vegetable oils & animal fats Biomass Mineral Oil (mainly animal fats oil) & Hydrogenation Refining Technology Esterification Fischer-Tropsch

Ester-based Bio-based biodiesel Hydrocarbon O hydrocarbon End product II H C-O-C-R C H etc. 3 CnH2n+2 n 2n+2 CnH2n+2

Figure 1. HVO contains the same paraffins (C nH2n+2 ) as conventional diesel fuel partly and GTL as a whole.

Chemically hydrotreated vegetable oils (HVOs) are mixtures of paraffinic hydrocarbons being free of sulfur and aromatics. Their distillation range is also inside the range of diesel fuels and well below the quite high-boiling FAME. Cold properties of HVO can be made to meet the local requirements by adjusting severity of the process or by additional catalytic processing. The of HVO is very high, and the other properties are very similar to the gas-to-liquid (GTL) synthesis product (Table 1).

Table 1. Typical properties of HVO (Neste Oil’s NExBTL TM ), European EN 590:2009 diesel fuel, GTL and FAME.

HVO EN 590 FAME NExBTL TM (summer grade) GTL (from rape seed oil) Density at 15 °C (kg/m 3) 775 ... 785 ≈ 835 770 ... 785 ≈ 885 Viscosity at 40 °C (mm 2/s) 2.5 ... 3.5 ≈ 3.5 3.2 ... 4.5 ≈ 4.5 Cetane number ≈ 80 ... 99 ≈ 53 ≈ 73 ... 81 ≈ 51 Distillation range ( °C) ≈ 180 ... 320 ≈ 180 ... 360 ≈ 190 ... 330 ≈ 350 ... 370 Cloud point ( °C) −5 ... −30 ≈ −5 −0 ... −25 ≈ −5 Heating value, lower (MJ/kg) ≈ 44.0 ≈ 42.7 ≈ 43.0 ≈ 37.5 Heating value, lower (MJ/l) ≈ 34.4 ≈ 35.7 ≈ 34.0 ≈ 33.2 Total aromatics (wt-%) 0 ≈ 30 0 0 Polyaromatics (wt-%) (1) 0 ≈ 4 0 0 Oxygen (wt-%) 0 0 0 ≈ 11 Sulfur (mg/kg) < 10 < 10 < 10 < 10 Lubricity HFRR ( µm) < 460 (2) < 460 (2) < 460 (2) < 460 Storage stability Good Good Good Very challenging

(1) European definition including di- and tri+ -aromatics (2) With lubricity additive

HVO meets the new CEN workshop agreement (“pre-standard”) CEN CWA 15940 class A specification for paraffinic diesel fuels. HVO also meets conventional diesel fuel requirements (e.g. EN 590, ASTM D 975, Worldwide Fuel Charter Category 4) except for the low limit of density in some specifications. FAME specifications do not apply for HVO due to the totally different chemical structure and properties.

Automotive manufacturers commonly prefer HVO over FAME since HVO does not increase NO x emissions or deposit formation in engine, fuel systems or injectors. Furthermore it does not have storage stability problems and it does not dilute or deteriorate engine oil. Operability problems at cold temperatures can also be avoided more easily. HVO is also practically free of metals and ash forming components like a high quality sulfur-free diesel fuel. Thus, HVO is compliant with sensitive exhaust after-treatment systems. For oil companies and fuel distributors HVO is as easy as diesel fuel because of good storage stability and low water pick-up tendency.

One significant benefit of hydrocarbon type fuels is their high energy content compared to other alternative fuel chemistries. For example the heating value of HVO (34.4 MJ/liter) is substantially higher than that of ethanol (21.2 MJ/liter). When also the better efficiency of diesel engines compared to spark ignition engines is taken into account, one liter of HVO can power a car about double the distance compared to an ethanol based fuel such as E85.

Quality of FAME is known to depend on the properties of the feedstock used but HVO can be produced from many kinds of vegetable oils without compromising fuel quality. This means that higher feedstock volumes are available for HVO. Existing farm based feedstock such as rapeseed, sunflower and can be used, as well as . However, as these feedstock compete with food production, alternative non-food oils such as jatropha and oil must be available in the future in large cost-effective volumes in order to be able to replace a significant portion of fossil based diesel. Waste animal fats can also be used as feedstock for the HVO process.

Feedstock sustainability challenges are the same for HVO as for FAME since their feedstock base is similar. Life-cycle greenhouse gas (GHG) savings of HVO compared to fossil diesel fuel have been estimated to be 40…60 % with palm oil as feedstock. Feedstock production and processes have a major effect on the life-cycle GHG, whereas the effects of hydrotreating are minor. It is of utmost importance that sustainability is taken into account throughout the whole production chain of the biofuel and, especially, it needs to be ensured that all the feedstock is produced in a sustainable manner.

In the HVO production process hydrogen is used to remove the oxygen from the triglyceride () and integration to an existing is preferred for small plants. Stand alone units become competitive as the scale increases. Additional chemicals, like methanol for FAME production, are not needed. Furthermore, the HVO production process does not produce any glycerol as a side product. In Figure 2, HVO and esterification routes are compared. Natural Methanol Natural HydrogenMethanol gas plant gas plant

≈ 10% methanol ≈ 2 ... 3 % hydrogen

Veg oil Esterification Biodiesel Veg oil HydrotreatingEsterification Renewable plant FAME Animal fat plant diesel, HVO () (LPG) Glycerol Water

Natural gas input about the same in both routes

Figure 2. HVO technology produces synthetic diesel (pure hydrocarbon) – thus providing an alternative to esterification (FAME), using the same original feedstock.

1.3. Neste Oil – a frontrunner in HVO

The first commercial scale NExBTL TM unit with 170 000 ton/a (3 800 bbl per day) capacity has been running since 2007 and the second one, similar in size, was started up at Neste Oil’s oil refinery in Finland in 2009. Large scale units with 800 000 ton/a (18 000 bbl per day) capacity will start in 2010 in and in 2011 in . This technology, branded NExBTL TM , is based on a separate unit at an oil refinery site while at the same time using existing logistics, utilities and quality-control facilities of the site. A separate unit like this can be optimized and run without interfering with the other refinery units, which may be a problem if bio-oils are fed into existing refinery units as blended with fossil feeds.

1.4. NExBTL TM technology

The NExBTL TM process contains catalytic hydrotreating of vegetable oils and animal fats. Hydrogen is used to saturate the double bonds and remove oxygen from the feedstock. An isomerisation is included to improve the product’s cold flow properties. The NExBTL TM renewable diesel or jet fuel is formed from the hydrocarbon chain of fatty acids (triglycerides) in the feedstock. A simplified process description can be seen in Figure 3.

Vegetable oils and animal fats Feed storage

Solids Pretreatment Removal of Impurities

NExBTL unit Bio gasoline Hydrogen Conversion of Bio jet fatty acids Water NExBTL diesel fuel Stabilization

Figure 3. Simplified NExBTL TM process description.

1.5 Use of biocomponents in diesel fuel

In principle, biocomponents can be used in diesel vehicles in three ways [1]:

1. By adding a few percents share of biocomponent into fossil diesel fuel. This is a common approach with FAME since the amount is currently limited e.g. to max 7 vol-% by the EN 590 standard. Higher amounts need extra precautions because of fuel stability, engine oil dilution and deposit formation in fuel injection systems.

2. By blending tens of percents of biocomponent into fossil diesel fuel. This is possible with HVO without compromising fuel quality, exhaust emissions and engine operation. In fact, the fuel blend will be premium grade since the cetane number is increased and aromatic content decreased resulting in lower exhaust emissions. These blends meet the current diesel fuel standards like EN 590 and ASTM D 975.

3. By using HVO as such in fleet operations like city buses in order to reduce exhaust emissions and improve local air quality. Benefits are seen in all vehicles including old high- emitters. Also tasks of exhaust after-treatment devices of new vehicle technologies will be easier since engine-out emissions are lower. To attain full benefits of the fuel plus engine combination the fuel injection system may need recalibration due to the lower density and higher cetane number of HVO [2]. Pure HVO meets CEN CWA 15940 class A specification.

2. EXHAUST EMISSIONS

The effect of HVO on regulated and unregulated emissions has been measured in several studies with passenger cars [3] and heavy duty engines and vehicles [4] using NExBTL TM renewable diesel (see Table 2). Generally, NO x, particulate, HC, CO and PAH emissions reduce remarkably. Also there is less visible smoke after a cold start. The reference fuel has been of high quality (sulfur-free EN 590 with quite low aromatic content) so that compared to some other diesel fuel grades the benefits of NExBTL TM would have been even larger. HVO’s emission trends are clearly different from FAME since FAME usually increases NO x and cold start smoke.

If HVO is used as a blending component in diesel fuel, NO x and particulate emissions reduce quite linearly as a function of the blending ratio. For CO and HC the beneficial effect of HVO takes place already with low blending ratios, obviously due to the increased cetane number. . Table 2. Effect of 100% NExBTL TM on exhaust emissions compared to sulfur-free EN 590 diesel fuel in truck and bus applications [4].

Effect of NExBTL TM on emissions Particulate mass − 28 … − 46 % NO x − 7 … − 14 % THC 0 … − 48 % (1) CO − 5 … − 78 % (1) (1) Due to very low absolute values (g/kWh or g/km) reduction for THC and CO is not as relevant and reliable as for particulates and NO x.

3. FIELD EXPERIENCE

3.1 trial

A three-year field program with NExBTL TM commenced in co-operation with Helsinki City Transport, Helsinki Metropolitan Area Council, Neste Oil and Proventia Emission Control in 2007. The project continues until the end of 2010 including some 300 city buses running with NExBTL TM content in the range of 30% -100% blended with premium conventional diesel.

The objective is to study the large scale use of high quality renewable diesel fuel in order to decrease toxic emissions (especially NO x and particulates) in urban environment. For urban fuels the reduction of GHG emissions cannot be the only target since local emissions are very important and some biocomponents are known to increase direct exhaust emissions. It is also the first large scale project using HVO in high concentrations. The immediate effects of HVO on exhaust emissions are measured and some measurements are made during the three years mileage accumulation in order to see if there is any drift in emission values. Performance and durability of engines and exhaust after-treatment devices is monitored over the test period.

Several bus operators and subcontractors, a supplier of retrofit exhaust after-treatment device, and one vehicle manufacturer take part to the project. Typical mileage of the buses is 60 000 km per year and no problems due to HVO have been reported so far.

All the emission research is conducted by VTT Technical Research Centre of Finland. Studies consist of laboratory screening on emissions and fuel consumption in buses which represent both old ( 2 certification, 1996) and new technology (EEV, Environmentally Enhanced Vehicles), and models between them. Totally 11 vehicles have been measured in dynamometer using the urban Braunschweig transient bus cycle. Follow-up of the vehicles takes place by monitoring the operational performance and emission stability in long-term service (22 vehicles). Also several exhaust after treatment tests are carried out. The effect of the fuel on particulate emissions and NO x emissions can be seen in Figures 4 and 5.

Based on Helsinki bus demonstration measurements at VTT

Figure 4. Particulate emission (PM) results of the Helsinki NExBTL TM trial [5].

Based on Helsinki bus demonstration measurements at VTT

TM Figure 5. NO x emissions results of the Helsinki NExBTL trial [5].

The effect of a fuel blend containing 30 % HVO on exhaust emissions compared to a sulfur- free diesel fuel was as an average of 11 buses: • NO x - 2 … - 5 % • Particulates - 11 … - 17 %

The effect of 100 % HVO on exhaust emissions compared to a sulfur-free diesel fuel was as an average of 11 buses: • NO x - 9 … - 12 % • Particulates - 27 … - 37 % • CO - 35 % • HC - 40 % • Polyaromatic hydrocarbons (PAHs) - 50 % • Energy consumption - 0.5 % • No significant change in ammonia and aldehydes emissions • No significant change in mutagenicity (AMES) of particulates (benefits might have been seen if the reference fuel had a higher polyaromatic content)

These measurements were performed with unmodified buses and results vary quite a lot between the bus models. Results are well in line with emission performance that can be found from literature from paraffinic GTL diesel fuels. Even more remarkable emission reductions or fuel consumption optimization can be achieved if the engine is calibrated for 100 % HVO by optimizing the fuel injection advance [2]. Since there are about 1400 urban buses in the Helsinki metropolitan area, changing their fuel to HVO would have the same effect as replacing 140 buses with zero NO x emission transport system, or 420 buses with zero particulate emission transport system.

3.2 German trial

The first results of a field trial on 100% NExBTL diesel fuel in Germany were announced in June 2009 and were also very positive. Fourteen standard Mercedes-Benz trucks and buses ran on the fuel every day from mid-2008 onwards, recording over 1 million kilometers in total by June 2009. Emission measurements have shown NO x reduction by up to 15 % compared to standard sulfur-free diesel fuel and GHG reduction of more than 60%. The trial is scheduled to last for three years in all and will end in 2011. The trial is being carried out together with Daimler AG, Deutsche Post DHL, the energy group OMV and the Stuttgarter Straßenbahnen AG public transportation company. Dr. Manfred Schuckert, company strategist at Daimler AG, stated that “the results from the first year of testing show that the fuel works perfectly in Mercedes-Benz trucks and buses and is tolerated very well by the engines”, in a press conference held in Berlin on June 9, 2009.

3.3 Canadian trial

NExBTL TM renewable diesel was also one of the fuels used in a biofuel trial that Neste Oil took part in between 2006 and 2009 in Alberta, Canada sponsored by the federal and provincial governments, together with Shell Canada. In the trial a 2% NExBTL TM diesel blend was used in the winter and 5% blend in the summer period. The results of laboratory and field tests were excellent here as well, and showed that a NExBTL TM diesel fuel blend can be used at temperatures as low as -44 °C. Over 75 different trucks and buses took part in the field trials, which lasted for 10 months.

3.4 Public sales in Finland

NExBTL TM has been used as a blending component (at least 10%) in EN 590 diesel fuel in Finland since May 2008. The blend has been marketed as a premium diesel fuel since HVO increases cetane number reducing engine noise and cold start smoke. Experience has been very good throughout the period.

4. OTHER HVO OPPORTUNITIES

Air traffic is projected to grow significantly in the future, and ways to reduce its GHG emissions are sought globally. The proprietary technology producing NExBTL TM can be tuned to meet jet fuel component requirements. It has great potential to offer GHG emission reduction benefits as such or as blended into conventional jet fuel.

5. RENEWABLE FEEDSTOCK

The production of biofuels will be limited by the availability of sustainably produced feedstock. As is common with all biofuels which use purpose grown feedstock such as corn ethanol and biodiesel, the biomass feedstock is the largest GHG emission source in renewable diesel. Hence, the feedstock source is critical. When animal fats are used which are classified as waste or by product from the rendering industry, emissions are minor. When the feedstock is grown for the purpose of producing a biofuel, the situation becomes more complex. For renewable diesel the main feedstock are rapeseed oil, palm oil and soya. Now direct emissions from e.g. diesel used for harvesting and shipping or from the production and use of fertilizers and also indirect emissions from land use changes are included. Significant reductions in GHG emissions can be achieved by improving farming methods, choosing crops which require less fertilizer and improving process steps for removing the oil from the plant and processing the residual biomass.

In order to calculate the carbon footprint of a biofuel, a greenhouse calculation is done. At present there are no widely adopted international methods for calculating GHG emissions for the full fuel chain. In the , the Joint Research Commission (JRC) together with Concawe and EUCar are the authorities on GHG emissions (http://ies.jrc.ec.europa.eu /wtw.html). In their analyses one finds a range of values depending on for example how co- products are credited, what default values are used for N 2O field emissions and what fuel source is used for process energy. Depending on what assumptions have been made, the overall fuel chain or WtW (Well to Wheel) emissions for HVO may vary by as much as 40 to 60 % of fossil diesel. Taken as savings, this means that using renewable diesel can save from 40 to 60 % of the GHG emissions of diesel. According to the JRC/Concawe/EUCar figures HVO is more efficient than FAME in reducing GHG emissions when produced from the same feedstock like rapeseed oil (51% vs. 45%) or sunflower oil (65% vs. 58%). Even higher savings may be obtained in the future when the mix of feedstock changes. Currently rapeseed oil is the most widely used feedstock for in the European Union. Taking into account the agreed biofuel mandates in the EU and assuming that the mandate was filled with only rapeseed oil based biodiesel, the European rapeseed production would require over 9 % annual growth without imports. Land and other limitations on the maximum amount that could be grown in the EU call for a clearly wider feedstock base.

New raw materials for the HVO process are being developed and tested. A plant that is currently under cultivation for biofuel use is jatropha. It can be grown on land not normally used for agriculture. It also contains minor levels of poisons which can be removed before processing into a biofuel but which restrict its use for human consumption. An alternative to jatropha which Neste Oil is also looking at are algae oils. These are fast growing species which can double their weight in a day and thus the amount of oil per land area used can be high. They can also be grown in salt water, thus saving fresh water for normal crops. They can also be grown in regions not suitable for agriculture so they will not compete with food. Algae development is at an earlier stage than jatropha and it will be a few years before large scale production is possible. Algae oil samples, however, are available already today and can be tested for their suitability as feedstock for a renewable diesel process.

Neste Oil is currently developing a biomass-to-liquids (BTL) technology together with , a major international pulp and paper company. A demonstration plant to convert forestry and mill residues into traffic fuel components for diesel and gasoline is running in , Finland. The process is comprised of gasification, gas cleaning and conditioning and chemical synthesis. The front end of the demonstration facility is currently operational while the remaining process steps are being installed. The goal for the project is to demonstrate the technology. Results from the demo plant are expected in 2010. Once proven, this technology could be used to convert various sources of biomass into high quality fuel components.

6. CONCLUSIONS

Hydrotreating of vegetable oils and animal fats is a novel process for producing high quality renewable diesel fuel. Many types of vegetable oils can be used as feedstock for HVO without problems with properties of the final product. Hydrotreated vegetable oil (HVO) is a premium product to be used in diesel fuel as a component or as such. HVO offers significant reductions of NO x, particulate, PAH and GHG emissions. It does not cause problems with engine cleanliness or engine oil deterioration which are major challenges for traditional such as FAME. When new engine and exhaust after-treatment technologies evolve, it is even more important that fuel combusts completely and without ash. That can be achieved with HVO. In the future engines could be optimized for HVO giving even more benefits.

Chemically HVO is a paraffinic hydrocarbon like GTL diesel fuel and BTL fuel in the future. In the fuel logistics system it behaves like diesel fuel without any additional challenges related to water-pick-up or storage stability. The HVO process can also be modified to produce jet fuel and help in reducing the GHG emissions of air traffic.

Production of biofuels will be limited by the availability of sustainably produced feedstock. Therefore, significant research and development efforts will be required to expand the current feedstock base. New routes for processing biomass into high quality transportation fuels will also be needed. Neste Oil has developed the leading, proprietary NExBTL TM technology in this field and intends to be a frontrunner in renewable fuels also in the future.

7. REFERENCES

1. Mikkonen, S., Second-generation renewable diesel offers advantages. Hydrocarbon Processing, 87(2008)2, p. 63 - 66.

2. Aatola, H., Larmi, M., Sarjovaara, T. & Mikkonen, S., Hydrotreated Vegetable Oil (HVO) as a Renewable Diesel Fuel: Trade-off between NO x, Particulate Emission, and Fuel Consumption of a Heavy Duty Engine. SAE Technical Paper 2008-01-2500. 12 p.

3. Rantanen, L., Linnaila, R., Aakko, P. & Harju, T., NExBTL – Biodiesel fuel of the second generation. SAE Technical Paper 2005-01-3771. 18 p.

4. Kuronen, M., Mikkonen, S., Aakko, P. & Murtonen, T., Hydrotreated vegetable oil as fuel for heavy duty diesel engines. SAE Technical Paper 2007-01-4031. 12 p.

5. Nylund, N.-O., Erkkilä, K., Solla, A. & Murtonen, T., Final technical report from the 1st phase of NExBTL Helsinki trial (in Finnish). Report VTT-R-09824-08, 2008. 104 p.