Greener diesels:Brazil

This chapter examines ways in which people all over the world are working to make diesel engines more socially useful and less harmful to the environment. The intensity of the effort is reminiscent of the 1960s and ’70s when some of the best minds dropped out of college to live on pizza and play with computers. Many of these enthusiasts work within the confines of corporations, firms such as Bosch, Denso, Stanadyne, Magneti Marelli. Others pursue their dreams on their own. Go by a London fish-and-chips joint early in the morning and, chances are, you will find one of these pioneers collecting waste cooking oil to use as diesel fuel.


In the summer of 2006, a group of students and technicians arrived at Vila Soledade1, a remote village built along the banks of the Amazon. Like hundreds of other communities in the region, Vila Soledade is remote from the national grid and must generate its own electrical power. In theory, the 700 or so townspeople could have electricity for five or six hours a day. But diesel fuel is an expensive luxury for farmers living barely above the subsistence level and their antique gen-set frequently broke down. Sometimes they waited weeks for parts. In terms of the government’s Human Development Index, the people in Vila Soledade are among the most disadvantaged in the country.

The team brought with them a Brazilian-built MWD TD229EC-6 generator powered by six-cylinder, turbocharged engine, modified to run on unprocessed palm oil. This oil is local product that costs nothing except for the labor involved in its extraction.

The modified engine circulates coolant through a holding tank to preheat the oil to 65°C (Fig. 13-1). A transfer pump then moves the warm oil through a filter to a second tank where it is heated to 85°C for injection. With heat, the palm oil moves from the viscous esterarine phase to the more pumpable oleine phase. Sensors

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report fuel pressure and ambient, fuel, and exhaust temperatures, which are recorded daily by the operator.

Vila Soledade now has electricity for six hours every day. To prolong filter life the engine is run for a half hour on diesel fuel immediately after starting and just before shut down. The rest of the time it operates on raw palm oil.

Stack emissions on diesel fuel and palm oil were found to be almost identical, except that the vegetable oil produced no sulfur oxide. An analysis of the lube oil allowed change periods to be extended to 200 hours, which was surprising, since straight vegetable oil (SVO) has a reputation for contaminating lube oil. Misfiring developed after 600 hours due to dirty injectors. The injectors were changed and at 800 hours the head was lifted to decarbonize the combustion chambers. The major problem was fuel filters that gummed over and required frequent changes.

Reliable and affordable electricity has transformed the community. With the money saved on fuel, the villagers purchased equipment to process acaí, one of the major crops of the region, and many families have purchased lamps, television sets, refrigerators, and freezers. Most adults now attend night school.

While the Vila Soledade project impacts less than a 1000 people, it is part of a national commitment to wean the nation from fossil fuels. According to Luis Inácio Lula de Silva, the President of Brazil, “In the next 10 to 15 years, Brazil will become the most important country concerning renewable energies. . . . No one will have the ability to compete with us.”

Lula’s confidence seems well placed. According to the government, 43.8% of Brazil’s current energy needs are met by renewable fuels, compared to 13.8% for the rest of the world. Ethanol has cut gasoline consumption almost in half, and a major push is underway to do something similar for diesel fuel.

The state oil company Petrobras squeezes as much as 20% more diesel fuel from conventional petroleum stocks by blending lighter hydrocarbons into the mix during refining. The tradeoff is a small reduction in heat value and a slightly lower flash point. Even so, the country still imports 10% of the diesel fuel it uses, which is a major draw on hard currency.

At the new century dawned, the government acted to reduce imports and, hope- fully, to improve conditions in the agricultural sector. In only 12 months it set the stage for a massive influx of biodiesel by organizing production, establishing a regulatory framework, and arranging lines of credit.

In 2003, Petrobras introduced B2, a 2% blend of various vegetable oils and conventional diesel into most areas of the country and, by 2010, B5 will be universal. The program follows traditional practice, in that the raw vegetable oil undergoes transesterfication (reaction with methanol and caustic soda) for conversion to a fatty acid methyl ester, or FAME. This process reduces viscosity to something over 4 mm2/s, which is in line with the European standard of 3.50–5.00 mm2/s. B2 has a density of 879 kg/m3 compared with 860–900 kg/m3 for European diesel.

B2 will yield an annual saving of 800 million liters of fuel and US $160 million that would be spent on imports. Several government agencies are working with Peugeot, International, and various parts suppliers to make B100 practical for agri- cultural machinery and portable power plants. Locomotives will, it is predicted, soon operate on B25 and, with some modification, heavy trucks should be able to use B10.

In addition, the Brazilians hope to export FAME to Europe, where legislation mandates 5.75% renewables by 2010. Europe does not have the agricultural base to support such a commitment.

In a parallel program, Petrobras has converted three refineries and is building several more to process vegetable oil by hydrogenation. According to the company, H-bio blends have superior ignition characteristics and have shown themselves to be harmless to fuel systems.

Researchers at the University of Brasilia have explored pyrolysis as a means of converting soybean, palm, and castor oils to diesel-compatible fuel.2 The technology is not new: pyrolysis was widely used in China during the Second World War to con- vert ming oil into feed stocks, which were then used to produce gasoline and diesel.

The university researchers used a stainless-steel reactor to distill vegetable oil into four fractions, at 80°C, 80°–140°C, 140°–200°C, and >200°C. These moderate temperatures left a heavy residue accounting for about 2% wt of the oil in the apparatus, which was discarded. As shown in Table 13-1, the distilled fractions have all of the salient characteristics of diesel fuel.

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