Process is flexible, regulated through the feeding of the reactor, and it generates gases with different compositions.
The traditional process for synthesizing natural gas is in the form of vapor, in which a chemical reaction forms water vapor with methane gas (CH4), with the help of a catalyzer. This process produces a mixture of gases, called synthesis gas, or syngas, whose main components are: CO and H2 (carbon monoxide and hydrogen). Both are the raw materials for the chemical, petrochemical, and steel industries, with a variety of applications. But there are other processes for producing syngas, such as oxidative reform, which uses oxygen and performs a partial burning of the methane, and the dry reform, in which the agent is carbon dioxide (CO2), instead of water vapor.
“Dry reform has the advantage of using the CO2 as a raw material. CO2 is also a component of natural gas. There are some wells where the CO2 content is 50%; the pre-salt wells are even higher,” states Professor Reinaldo Giudici, of Poli/USP, who is also a researcher for the Research Center for Gas Innovation (RCGI), where he coordinates the Synthesis Gas Production by Methane Tri-reforming project. He explains that each one of these ways of obtaining syngas originates a gas with different proportions of CO and H2.
“The tri-reform idea is to simultaneously combine the three processes. The reactor would be fed by natural gas, carbon dioxide, water vapor, and oxygen. Thus, we are able to use a process in which it is possible to regulate the conditions for generating synthesis gas needed for a given operation, depending on the variables, such as the occurrence of raw materials, for example. It is a more flexible process, which generates gases of different compositions, regulated by feeding in the different reagents. By combining the appropriate catalysts, this is easy to do,” he summarizes.
The engineer states that the tri-reform ensures greater usage of the raw material. “If you feed the reactor with a natural gas having a high CO2 content, for example, then the carbon dioxide become a raw material for the dry reform. It does not need to enter the reaction separately. It automatically becomes a raw material.”
The project is divided into two fronts: the development of the catalyzer and the determination of the kinetics of the process for generating syngas from the tri-reform. “In order to develop the catalyzer, we are studying different compositions and ways to feed into the active phase. The traditional catalyzer uses aluminum as a support and the active phase is nickel. We are looking for other supports, besides aluminum. Once it is developed, we will do a performance study of the catalyzer.”
Determining the kinetics of the process is important for feeding into simulation model of the tri-reform reactor, which also will be developed. “We want to know how the velocity of this reaction depends on the concentration of the different species in the reactional state – water vapor, carbon monoxide, oxygen, carbon dioxide and methane. This information on the kinetics will be used to feed into a mathematical model of the process, in order to do simulation studies of the tri-reform reactor. We will be able to study what is the best or most economical operation condition, or what provides more performance, for example.”
Giudici states that the production of syngas is influenced by the uses that will be made of it by the various units that use it, in a large industrial structure. “Knowing in under what conditions the reactor will operate is important for optimizing the unit as a whole. The conditions could be altered to better serve this or that process.” He added that the research will simulate different scenarios for the tri-reform: best performance and most profit of the unit as a whole, best use of the raw material, lest generation of effluents….
“We will give the inputs into the system, specifying the type of syngas that we need, and the raw material that we have at hand. And it will calculate the amount o9f each raw material that we will place in the reactor, under what temperature and pressure conditions we should operate, how to integrate that with the peripheral processes of the reform, how much energy we will need….” The project has total duration of five years and there are eight researchers involved, all from Poli/USP.