THERMODYNAMIC ANALYSIS OF BEHAVIOUR IN A COMBINED CYCLES OPERATING WITH BIOGAS AND MUNICIPAL SOLID WASTE

Abstract

The research and development of technologies using wastes have been advanced over the last decades. Along these lines, the use of biogas from landfills, and Municipal Solid Waste (MSW) as fuel has a relevant role in the context of energy generation and environmental protection. The use of MSW as fuel to produce energy has the advantage to abate the use of landfills, which are responsible for problems such as space loss and sanitation that large cities have to deal with. However, the MSW and biogas available in landfills have been used individually to generate power, or in systems where energy conversion is in development. Thus in this research the choosing of the technology that better fits in thermal conversion systems, using MSW and biogas, was carried out. The main technologies of thermal conversion of MSW, including gasification, pyrolysis, and incineration, were verified. Among the technologies above, incineration is the most and its present used in huge-sized facilities in the world. Regarding the most used technologies for thermal energy conversion of biogas, combustion in boilers, or engines and small turbines, can be addressed. Therefore, it is possible to verify that most of those systems can use many kinds of fuels; furthermore, there are many options to combine these technologies, for instance, using Combined Cycles. The present work aims to perform a thermodynamic analysis (energy and exergetic analyses) of a Combined Cycles composed of the internal combustion engine to burn biogas, and a gasification system of MSW combined with a system to burn syngas to produce steam and operate in a Rankine cycle. Because the MSW and biogas compositions are not singular over time, a thermodynamic analysis evaluating the influence was performed of this variation in the behavior of the power plant.