According to professor José Roberto Simões Moreira, from the Polytechnic School of the University of São Paulo (Poli-USP), the main aim is to make the steam reforming process cheaper, using concentrated solar energy as a supplied material.
One of the most common processes used for the synthesis of natural gas is the process known as steam reforming, in which there is a chemical reaction between steam and methane (CH4). This process produces two gases (collectively known as synthesis gases or syngas): CO and H2 (carbon monoxide and hydrogen). Both are raw materials for the chemical industry, as also for the petrochemical and steel smelting industries, with several applications. In fact, hydrogen is often considered the fuel of the future, in a scenario of a carbonless economy. Both can also be used in systems for generation of electrical energy, activation of turbines, motors and other processes involving combustion.
“Steam reformation is a process that needs a lot of energy, because the chemical reactions occur at temperatures or around 800 °C, which is a very high temperature. Normally, the energy required to obtain this temperature comes from the combustion of fossils, and often of natural gas itself. Our proposal is that the energy demand which is necessary for this purpose should be mainly of solar origin”, explains professor José Roberto Simões Moreira, of the Laboratory of Alternative Energy Systems (SISEA) of the Polytechnic School of the University of São Paulo (Poli-USP).
Mr. Simões and his team are responsible for the Project known as Chemical Process: A Hybrid Solar System for Natural Gas Steam Reforming, which is one of the 28 projects that have already been initiated by the Research Center for Gas Innovation (RCGI) – www.usp.br/rcgi). They are starting to construct the first simulator of solar energy concentrated in Brazil, a prototype at laboratory level, for obtaining syngas.
For this, they will use a paraboloid reflector with a diameter of some 1.5 meters, with four xenon lamps, which issue heat and light radiation, whose characteristics are close to those of solar radiation, and also a reactor in ceramic materials, to which the radiation will converge, after it has reflected (a type of thermochemical reactor).
“Ideally, all the energy used in the reaction could come from the sun. However, the system is hybrid because we may need to use fossil combustion to generate part of it. What we do know is that, with solar energy, the cost of energy is sure to be less than that observed in the traditional method. How much less is something we cannot yet say, this is one of the answers that we are now seeking”, says Mr. Simões.
The idea is that of reducing the energy supply necessary for each unit of synthesis gas that is produced. According to Mr. Simões, when the sky is clear, in the summer, the sun sends the earth (in radiation) about 1,000 watts in power per square meter at ground level. This is between 1 a 2 p.m., when we have the best conditions. “However, with the use of the paraboloid dish, it is possible to turn this thousand into ten thousand suns, through concentration”.
This is pure optics. When light rays fall upon a concave surface, the surface reflects the rays and concentrates them in one single point (focus). The larger the surface, the greater the concentration of energy will be. At this point, a small reactor of ceramic materials (known as a cavity) will be placed where the radiation will be trapped and where the chemical reactions will occur. “The cavity simulates a black body: the opening of the cavity is at the focus of the paraboloid, while the radiation will be absorbed there.”
For the construction of the prototype, a SISEA room with an area of approximately 15 m², which is now being refurbished and adapted, will be used, also with regard to the security protocols that the experiment requires. The project will have a duration of five years, but the team intends to have everything ready, and up and running, within four years. “We want to dominate this technology, so that the big producers of natural gas, such as BG, who sponsor the Project, may show interest and then, in the future, develop their own plants. This is an issue of cutting-edge research abroad: the use of solar energy to promote thermochemical reactions and also, in a broader sense, for the production of solar fuels”, Mr. Simões emphasizes.
The RCGI (www.usp.br/rcgi) was set up at the end of last year, to investigate the current and future use of natural gas, with the ultimate aim of increasing its participation in the energy matrix of the Country and reduce the emissions of greenhouse gases. Natural gas has a strategic role in the transition from an energy matrix based on fossils to a cleaner matrix.
With a forecast volume of BRL 100 million in investments made by the Foundation for Research Support of the State of São Paulo (Fapesp) and BG Brazil (a company of the BG Group which has recently been acquired by Shell), RCGI is investigating, apart from the use of solar energy for the production of syngas, the use of natural gas as a fuel for ships, advanced combustion, fuel cells for hydrogen, and other issues.