Valter Silva

By Nuno Couto and Valter Silva

Recent reports from top universities state that in spite of having great national importance, there are dozens of fields of study that are suffering due to a lack of funding. Perhaps the greatest tool available to assist researchers with this regard is numerical simulation. This tool allows cutting costs, decreasing the necessary design cycle and allows an enormous amount of physical insight on the process itself). Numerical model’s ability to correctly predict a complex system was tested in this chapter by drawing from a previously developed computational fluid dynamics model for biomass gasification. Numerical results were compared with both experimental results (pilot scale plant) and available literature. Results from common Portuguese biomass substrates were found to be within a satisfactory margin of error of 20%. Influence of all major operational conditions was then investigated and the model was once again able to predict all the expected trends. All the relevant process products were also analyzed. Finally, the numerical model was coupled with an optimization model. Maximum efficiency value was found at 900°C with a SBR of 1.5 for MSW and 1 for forest residues. Results showed that numerical models could have a preponderant impact on biomass gasification field.

Part of the book: Biomass Volume Estimation and Valorization for Energy

By Valter Bruno Reis e Silva, Daniela Eusébio and João Cardoso

Part of the book: Statistical Approaches With Emphasis on Design of Experiments Applied to Chemical Processes

By João Cardoso, Valter Bruno Reis e Silva and Daniela Eusébio

Part of the book: Low Carbon Transition

By José Antonio Mayoral Chavando, Valter Silva, Danielle Regina Da Silva Guerra, Daniela Eusébio, João Sousa Cardoso and Luís A.C. Tarelho

Millions of tons of forest residues, agricultural residues, and municipal solid waste are generated in Latin America (LATAM) each year. Regularly, municipal solid waste is diverted to landfills or dumpsites. Meanwhile, forest and agricultural residues end up decomposing in the open air or burnt, releasing greenhouse gases. Those residues can be transformed into a set of energy vectors and organic/chemical products through thermochemical conversion processes, such as pyrolysis and gasification. This book chapter provides information on current examples of gasification on large scale in the world, which typically operate at 700°C, atmospheric pressure, and in a fluidized bed reactor. The produced gas is used for heat and energy generation. Whereas pyrolysis at a large scale operates around 500°C, atmospheric pressure, and in an inert atmosphere, using a fluidized bed reactor. The produced combustible liquid is used for heat and energy generation. The decision of using any of these technologies will depend on the nature and availability of residues, energy carries, techno-socio-economic aspects, and the local interest. In this regard, the particular situation of Brazil and Mexico is analyzed to implement these technologies. Its implementation could reduce the utilization of fossil fuels, generate extra income for small farmers or regions, and reduce the problem derived from the accumulation of residues. However, it is concluded that it is more convenient to use decentralized gasification and pyrolysis stations than full-scale processes, which could be an intermediate step to a large-scale process. The capabilities of numerical models to describe these processes are also provided to assess the potential composition of a gas produced from some biomass species available in these countries.

Part of the book: Gasification

By José Antonio Mayoral Chavando, Valter Silva, João Sousa Cardoso, Daniela Eusébio and Luís A.C. Tarelho

Despite the advantages of gasification over combustion, some elements remain to improve. Fortunately, it is not necessary to reinvent the wheel to improve efficiency and quality because there are already methodologies that have been proven successful with other processes, like the Six Sigma DMAIC methodology. Therefore, this chapter explores the synergies between gasification and Six Sigma DMAIC to improve gas quality and hydrogen production, using RDF and wood as feedstock. Furthermore, the blends and equivalence ratio influence the produced gas is explored.

Part of the book: From Biomass to Biobased Products [Working title]