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Soybeans in the refinery

Petrobras's research center develops technique for using vegetable oil in the production of diesel

MIGUEL BOYAYANDiesel and soybean oil: blend is going to produce H-Bio, a less pollutant fuelMIGUEL BOYAYAN

Mixing soybean oil in the diesel refining process is the new technology developed over 18 months by researchers from Petrobras’s Research and Development Center (Cenpes). Unprecedented worldwide, the new production system already has patents registered in Brazil and abroad. The diesel, used by trucks, buses, tractors, boats, locomotives, generators and industrial machines, will not undergo any essential modifications in its chemical structure, which will continue to be the same. As it is the same fuel, complementary tests in vehicles will be avoided. The tests carried out in the company’s laboratories and pilot plants approved the product for immediate use.

The new diesel may also not be classified as biodiesel. Biodiesel is the addition of vegetable oil to the diesel, at the fuel distributing companies. These oils pass before through a chemical process of transesterification, when it is purified so as not to cause problems in the engines. The new fuel is born during the refining process. “The soybean oil is inserted during the production of the diesel”, says Alípio Ferreira Pinto Júnior, Cenpes’s general manager for supply. The fuel will be available at the service stations as from 2007, and it will contribute towards reducing the imports of this product or of the thicker oil used to produce it, which exists in small quantities in Brazilian oil wells.

Of the 40 billion liters of diesel used in the country in a year, 2.3 billion was imported in 2005. To start with, Cenpes calculates that 256 million liters a year of the new diesel will be produced, almost 10% of the total currently imported. The first batches of the fuel will be produced in Minas Gerais, in the city of Betim, at the Gabriel Passos Refinery (Regap), and in Paraná, at the President Getúlio Vargas Refinery (Repar), in the municipality of Araucária. Later on, other refineries may also produce the new fuel, as in Canoas, in Rio Grande do Sul, and Paulínia, in São Paulo.

The two refineries are now passing through a logistical adaptation to receive and to store the soybean oil, which will reach it by truck. Besides being close to the soybean-producing centers, these units have hydrotreatment stations, which are fundamental for producing the new diesel, which will bear the name of H-Bio. “These stations use the hydrogen to remove sulfur molecules from the diesel”, Pinto Júnior says. Within this process, there are severe pressure and temperature conditions, besides the addition of other chemical products that cause catalysis (they accelerate the chemical reaction) the hydrogen also breaks up the molecules of the vegetable oil, which are transformed into mineral oil (diesel). The process can handle a mixture of 90% of diesel and 10% of vegetable oil. “Of each 100 liters of soybean oil included in the process, 96 liters are transformed into vegetable oil.” There is also propane (liquefied petroleum gas) left over, which can be also be put to good use, and water.

New market
Soybeans were chosen by Petrobras because their production is based on a widely disseminated crop and a well developed agroindustry in Brazil. This sector is also a great exporter, although in the last few years the prices have been falling for the Brazilian producers, due to the fall of the dollar in relation to the real and to the excess of grain in the world market. “The forecast is that Petrobras will consume 10% of the soybean oil currently exported, which is 2.7 billion liters”, says Pinto Júnior. Brazil produces 5.6 billion liters. Soybeans, though, are merely one option, the easiest to be obtained at the moment. In technical terms, other plants have already proved to have a good quality for refining diesel. “We have now done positive tests with castor, babassu and oil palm, amongst other plants.”

Less sulfur
One of the innovative advantages of the H-Bio diesel is that, with the adoption of soybean oil, it is possible to eliminate for good the sulfur that there usually is in this fuel. When cast into the atmosphere, this element can be transformed into sulfur dioxide and even into sulfuric acid, contributing towards acid rain. The diesel sold in Brazil has between 0.20% and 0.05% of sulfur. The one with the lower figure is distributed in the metropolitan regions with a larger population.  Besides environmental benefits, the H-Bio is also going to make better ignition possible. “It has a high level of octane (which is one component of diesel), and this indicates a good quality ignition”, Pinto Júnior explains. Also called cold start, this function, with good performance, makes possible a combustion of better quality and savings in fuel.

Amongst the economic benefits is the fact that agribusiness is becoming a direct supplier to the oil industry, for the refining stage. From now onwards, Petrobras is going to keep an eye not only on the international oil quotations but also on the international soybean prices when signing supply contracts with the suppliers of this oil-producing plant. In the case of sugarcane alcohol and biodiesel, the supply goes directly to the distributor, without passing through the refineries. The adoption of H-Bio also increases the share of biomass in the Brazilian energy matrix, consolidating the vanguard position of research into renewable fuels in Brazil.