Waste to energy via the plasma gasification of biomass

Abstract

In this research the effectiveness of a Nitrogen Plasma gasification pilot plant was tested in the generation of electricity from biomass using Aspen Plus models. This involved developing a model of an existing pilot scale plasma gasification reactor and consolidating this model with data from this plant. The effluent of the plasma gasification reactor plant is treated and combusted in power cycles to test the amount of power that can be generated. The power cycles modelled include a Brayton cycle, a Rankine cycle and a combined power cycle. In the modelling phase some modifications are made to these power cycles with the aim of recovering waste heat and improving the usage of heat within them. An analysis of these integrated plasma gasification combined cycle (IPGCC) models is performed through the first and second laws of thermodynamics to determine their energy and exergy efficiency. The energy analysis of the process found that the performance of the plasma gasification reactor was within industrial standards at a cold gas efficiency of 67%. The integration of the plasma gasification reactor and combined power cycle models generated the best power outputs and thermal efficiencies of 20.64kW and 44.14%, respectively. Most of the power cycle case studies were found to be operating below small scale industrial capacity thus alternative means of using the technology were recommended. An IPGCC system using a gas turbine and generating steam with the waste heat from the gas turbine effluent was found to be the best possible application of such a technology. This could be implemented in a hospital or clinic found in a rural environment with a limited supply of power and a substantial demand of low pressure steam.