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Biodiesel can be processed by esterification or by biomass-to-liquid (BTL) process. Neste Oil has developed a BTL diesel component NExBTL utilizing a proprietary conversion process for vegetable oils and animal fats. NExBTL biodiesel properties are similar to the best existing diesels such as GTL or Swedish Environmental Class 1 fuels. NExBTL is sulfur-, oxygen-, nitrogen- and aromatic free and has very high cetane number. Product meets the requirements set by EN590 and WWFC category 4 except for density. Cold properties (cloud point) of NExBTL can be adjusted in the production from -5 … -30°C to meet the needs of various climatic conditions. Heating value is similar to the EN590 hydrocarbon fuel, storage stability is good and water solubility low. NExBTL biodiesel is compatible with the existing vehicle fleet as well as diesel fuel logistic system and is technically easy to blend in conventional diesels in all ratios.

The effect of total olefin content on ozone forming potential has been widely studied. As a result a stringent limit for olefins is already given in California Specification for “Phase 2” gasoline and the 18 vol% limitation of olefins is expected to tighten also in Europe. However, it is not clear how determining the light olefins are and what is the role of heavy olefins regarding ozone forming potential. Ethanol is widely used as gasoline component in many countries, but not extensively in Europe. The biofuels have the potential to provide a renewable source of energy and contribute to lower global CO2 emissions. The unregulated emissions, especially particulates and their quality have not been studied extensively with ethanol containing gasoline using European test fleet. The objective was to study the applicability of heavy olefins in non-oxygenated and ethanol oxygenated gasolines. Alkylates in gasoline were replaced by isooctene.

Plans to ban MTBE (Methyl tertiary-Butyl Ether) have led to discussions on how the gasoline in California will be formulated without any backsliding in air quality. One possibility is to replace MTBE with isooctane. Exhaust emissions using California Phase II gasoline with MTBE, were compared to a gasoline where MTBE had been replaced with isooctane. Regulated, particulate, carbon dioxide, and PAH (polyaromatic hydrocarbons) emissions were measured at 22 °C temperature for 8 vehicles using the European cycle for year 2000 (ECE+EUDC). One of the vehicles was a GDI (Gasoline Direct Injection), one was a carbureted model without a catalytic converter, and the others were equipped with multi point fuel injection and catalytic converters. Results indicate that no major backsliding in air quality can be expected when replacing MTBE with isooctane. NOx (nitrogen oxides) emissions were reduced in all vehicle types. CO emissions increased in the vehicle without a catalytic converter.

Air quality monitoring of PM10 and associated health studies have focused interest on the size and the number of particles emitted to, and found in, the atmosphere. Automotive sources are one of the important elements in this, and CONCAWE have completed a study of heavy duty diesel particle emissions, complementing their previously reported light duty work. This heavy duty programme, presented here, investigated the nature of particulate emissions from two heavy duty engines (representative of different emissions levels), operating on three marketed fuels, over their respective European legislative heavy duty test cycles. The programme has investigated some of the complexities associated with obtaining credible data (e.g. dilution ratios, system stabilisation time etc.). The number distributions, which were measured over a wide size range (3 to 1000 nm), have been split into two size ranges, representative of nucleation mode and accumulation mode particles.

Exhaust emissions from cars using reformulated gasoline (RFG) that meets European 2005 regulations for gasoline quality were compared to the emissions from cars using gasoline that meets European 2000 regulations (EU2000). Methyl Tertiary Butyl Ether (MTBE) and Tertiary Amyl Methyl Ether (TAME) were used as oxygenates in the reformulated gasoline. The EU2000 gasoline contained no oxygen. Regulated, particulate and PAH exhaust emissions were measured at 22°C for 7 cars and at -7°C for 5 cars using the European MVEG cycle for year 2000 (ECE+EUDC). One of the cars was equipped with a lean burn engine, one with a direct injection engine and one was a carburetor equipped car without a catalytic converter. All other cars were equipped with multi point port fuel injection and a catalytic converter. Mutagenic activity of particulate mass was evaluated using the Ames test.

Effect of fuel reformulation (aromatics from 35 to 20 vol-%, sulfur from 0.05 to 0.005 wt-%) on exhaust emissions was measured from a car using ECE/EUDC tests. 14 PAHs, mutagenicity by Ames test and DNA adducts by using 32P-postlabeling were measured from the particulate soluble organic fraction (SOF). PAH-derived DNA adducts were measured in calf thymus DNA and human breast cancer MCF-7 cell line. Ames test and DNA adduct test measure the genotoxicity and metabolically activated PAHs in exhaust particulate SOF. PAHs, mutagenicity and DNA adducts were clearly reduced in SOF, which is a benefit caused by fuel reformulation.

Diesel fuel was reformulated by reducing sulfur to < 0.005 wt-%, aromatics to < 20 vol-% and by limiting heavy polyaromatics. This reduced NOx, particulate, PAH and mutagenic emissions plus exhaust odor. Oxidation catalysts operated well. Less deposits formed in the EGR system. Fuel lubricity was enhanced by additives evaluated by injection pump tests and HFRR. Three years of field testing with 140 buses showed no fuel related problems. Oil change period could be lengthened and fuel consumption was unchanged. Demand for reformulated fuel was triggered by differentiating taxation based on quality. Fuels have been used since 1993 without problems. Life cycle analysis showed no increase of CO2.

Unregulated emissions of reformulated diesel fuels (sulfur < 50 ppm, aromatics < 20 vol-%) were compared to the European EN590 specification fuel (sulfur < 500 ppm, aromatics < 35 vol-%) in three IDI passenger cars and one DI van using FTP and/or ECE/EUDC emission test procedures. The effect of reformulated diesel fuels on the mutagenicity of particulate soluble organic fraction (SOF) was studied. Fuel reformulation reduced particulate emissions in IDI cars. Reformulating fuel by decreasing heavier aromatics - without decreasing final boiling point - reduced particulate mutagenicity on emission basis. At low ambient temperature (-7°C) particulate PAH and mutagenic emissions increased compared to the standard ambient temperature (+22°C) with all fuels.

Diesel fork-lifts are often preferred over LPG due to lower costs and superior fire safety in in-door use but exhaust causes problems. Air quality was measured with standard and reformulated diesel fuel in a warehouse where diesel fork-lifts operated. Sulphur was 605 ppm for the standard and 7 ppm for the reformulated fuel. Aromatics were respectively 31 vol-% and 12 vol-% and 95-% distillation points 352 °C and 286 °C. Fuel reformulation reduced particulates in the ware-house air by 40 %, particulate SOF by 50 % and mutagenicity of SOF by 80 %. NO, NO2, SO2 and PAH concentrations were low. Irritation and the possibility of long-term health problems reduced.

Emissions of heavy duty engines using hydrocarbon fuels and rape seed methyl ester (RME) were measured according to the ECE R49 test procedure. The effect of fuel density on engine power was taken into account in the ECE R49 tests. The two reformulated fuels tested had sulphur below 50 ppm, aromatics below 20 vol-%, cetane number over 49 and reduced triaromatic content. Particulates were measured in a AVL Mini Dilution Tunnel 474 and gaseous unregulated hydrocarbons by Siemens FTIR. Reformulation reduced NOx by 5 to 12 %, particulates by 10 to 25 % and Ames mutagenicity by 56 to 74 %. RME increased NOx by 4 to 9 %, reduced particulates by 0 to 33 % and the mutagenicity by 17 %. Cetane number was found to be not important in reducing emissions. Low fuel triaromatic and low particulate PAH content reduced the mutagenicity of particulates.