Three municipal solid waste gasification technologies analysis for electrical energy generation in Brazil.

In Brazil, in 2016, 196,050 tonnes day-1 of municipal solid waste (MSW) were collected, which means a waste generation of 1.035 kg per capita per day. Only 59.1% of the waste has adequate destination in sanitary landfills, whereas the remaining 40.9% has inadequate destination in controlled landfills and open dumps (ABRELPE, 2018). Among all the states in the country, the State of São Paulo has the biggest per capita generation: 2.290 kg. Today, the only waste destination practiced in the country is deposition in landfills, but other possibilities can be considered. Among thermal treatment routes, the gasification of MSW is an interesting alternative to be studied, because of its versatility and relatively low emissions. The aim of this work is to evaluate the potential of electricity generation through MSW gasification in Santo André city, Brazil, comparing three waste gasification technologies: TPS Termiska Processer AB, Carbogas and Energos. These alternatives have operated commercially for a few years, and data are available. Specific characteristics of each technology were taken into account, such as the reactor type and fuel properties. For the electricity production scheme, two energy conversion systems were assumed: an internal combustion engine and a steam power cycle. From the process parameters adopted, the results showed that Carbogas technology, coupled to internal combustion engines, presents the highest efficiency of electricity generation (30%) and also the lowest cost of electrical energy produced (US$65.22 MWh-1) when Santo André's gate fee is applied.

Evaluation of two different alternatives of energy recovery from municipal solid waste in Brazil.

Brazil has a large population with a high waste generation. The municipal solid waste (MSW) generated is deposited mainly in landfills. However, a considerable fraction of the waste is still improperly disposed of in dumpsters. In order to overcome this inadequate deposition, it is necessary to seek alternative routes. Between these alternatives, it is possible to quote gasification and incineration. The objective of this study is to compare, from an energetic and economic point of view, these technologies, aiming at their possible implementation in Brazilian cities. A total of two configurations were evaluated: (i) waste incineration with energy recovery and electricity production in a steam cycle; and (ii) waste gasification, where the syngas produced is used as fuel in a boiler of a steam cycle for electricity production. Simulations were performed assuming the same amount of available waste for both configurations, with a composition corresponding to the MSW from Santo André, Brazil. The thermal efficiencies of the gasification and incineration configurations were 19.3% and 25.1%, respectively. The difference in the efficiencies was caused by the irreversibilities associated with the gasification process, and the additional electricity consumption in the waste treatment step. The economic analysis presented a cost of electrical energy produced of 0.113 (US$ kWh-1) and 0.139 (US$ kWh-1) for the incineration and gasification plants respectively.