Innovation at SIX
Petrobras’ pioneer project, developed for the capture of CO2 and unprecedented in the world, will be tested in its Shale Industrialization Unit.
Petrobras will carry out an unprecedented experiment in its Shale Industrialization Unit, SIX, located in the city of São Mateus do Sul, in the Brazilian state of Paraná. The capture of carbon dioxide (CO2) will be tested on a demonstration scale in a Fluid Catalytic Cracking Prototype Unit. The experiment is a world first and is necessary to make possible the use of the technology on an industrial scale and thereby reduce the release of emissions into the atmosphere of one of the gases most responsible for increasing the greenhouse effect and global warming. The first test should take place in 2009.
In the catalytic cracking process, the heavier particles produced in the distillation of oil are broken down into smaller molecules by the action of the catalyst particles, which generates products like gasoline and GLP. This process is carried out inside a converter and generates an accumulation of coke, that is, a carbon residue, on the surface of the catalyst. As the coke deactivates the catalyst, it is necessary to burn off this residue so that the catalyst can be reactivated. This burning is done by means of injecting air, which generates a gas containing between 10 and 15% of CO2 and which is released into the atmosphere.
To capture this CO2 before its emission into the atmosphere, Petrobras has developed a technology, oxicombustion, which has the potential to reduce the carbon dioxide in the Refining area by about 37%, in addition to costing about 50% less than traditional technology. Studies to develop this technology began in 2004. Since then, laboratory tests were carried out by Petrobras and the Federal University of Rio de Janeiro, acting in partnership. Finally, the technical viability was demonstrated in the Petrobras research and development center, CENPES. Today, a project for the capture of CO2 is in progress in the Fluid Catalytic Cracking Unit.
“In oxicombustion, pure oxygen is substituted for air, which makes the CO2 in the resulting gas more concentrated and, therefore, easier to capture. To avoid the sudden temperature rise and the reduction of the fluidization of the catalyst, undesirable side effects resulting from the injection of pure oxygen into the converter, part of the CO2 is recycled and the gas and the pure oxygen are mixed,” explains Leonardo Mello of CENPES, technical coordinator of the Fluid Catalytic Cracking Unit project for the capture of CO2.
This technology results in several benefits. “The percentage of reduction of carbon dioxide emissions in the Refining area is considerable. Taking into account, for example, that in 2008 total emissions projected are approximately 17 million tons, the reduction would be 6.29 million tons. The 50% cost reduction is highly advantageous. Another advantage is that part of the captured CO2 can be used for the advanced recovery of oil in mature fields, by means of injecting gas into wells already drilled. In addition, the CO2 can be used in the production of urea, a basic component in the production of nitrogen fertilizers. In this case, the scarcer natural gas is substituted. In the medium and long terms, CO2 can also be used in the nourishing of microalgae, from which the oils extracted can in turn be used to make high productivity biodiesel,” emphasizes Oscar Chamberlain, technological manager of the CENPES Fluid Catalytic Cracking project.
Worldwide attention has been attracted by the results of the implementation of this innovative technology, to the point that, of the thirteen international projects for the capture of carbon dioxide, the Petrobras project is ranked first by the Carbon Capture Project – Phase 2 (CCP – 2), a multiclient consortium joining eight energy companies (British Petroleum, Chevron, Eni, Suncor, Shell, ConocoPhillips, StatoilHydro, and Petrobras), whose objective is to promote the development of CO2 capture technologies. This is another victory for SIX, which, thanks to its similarly innovative, world-acclaimed technology for the extraction and processing of shale, Petrosix, has been a pioneer since its foundation. And may it continue in this way in the years to come.
Microalgae generate biodiesel
The Petrobras research and development center, CENPES, in partnership with the Federal University of Rio Grande (FURG) and the Federal University of Santa Caterina (UFSC) has developed laboratory research with the objective of studying microalgae and their reproduction to be used in filtering CO2 in the environment, replacing it with oxygen and generating biodiesel.
Researchers have collected samples from various aquatic environments in Rio Grande do Norte, which contain thousands of microalgae, invisible to the naked eye. In the laboratory, the samples are placed in ovens with adequate temperature and illumination set to maintain the algae alive. Later, using micro pipettes, each water sample is put in drops onto slides where the microalgae are captured, isolated, and classified. Each species is then placed in a photo bioreactor with micronutrients for reproduction. Days later, the microalgae are placed to dry and are wrapped to avoid contact with light or air. The dried microalgae are then placed in a reactor where the oil they carry is extracted. This oil is returned to the reactor, where, through a chemical reaction, biodiesel is generated.
Petrosix
The Petrobras Shale Industrialization Unit, SIX, possesses a consolidated technology, patented and renowned worldwide, for the extraction and processing of shale, a sedimentary rock which is the Unit’s raw material. This technology is called Petrosix and comprises the stages described below.
Shale, which contains kerogen, that is, an organic complex which decomposes by a thermal process and produces oil and gas, is extracted from open cast mines. The raw material is then transported to a crusher where the rock is reduced to fragments. The fragments are carried on a conveyor belt to a vertical cylindrical reactor, also known as a retort, where the material is brought to a high temperature. The shale then releases organic material in the form of oil and gas.
In another stage, the shale is cooled, which results in the condensation of oil vapors, which are then carried out of the retort by the gases which form. The shale gases pass through another cleaning process to produce light oil. The remainder is sent to a gas treatment unit where combustible gas and liquid gas (LPG) are produced and where sulfur may be recovered.
Today, SIX processes 7,800 tons of shale daily, in complete conformity with the requirements of international norms of quality, environment, health, and safety in the workplace.
