Investigation on Plasma Pyrolysis Process With Municipal Solid Waste/refused Derived Fuel as Feedstock

Abstract

With increasing population, urbanization, and economic development, especially in developing countries, waste generation is increasing sharply. Municipal Solid Waste (MSW) contains plastic, paper, glass, metal, construction waste, etc., and is generated in thousands of tonnes in most Indian cities. Waste management is one of the most challenging tasks as most developing countries generally don’t have mechanisms to collect segregated waste. The most simple way for this waste management is landfilling. However, due to improper landfilling, many problems such as air pollution and greenhouse gas emissions, contamination of underground water sources, etc. Plasma pyrolysis is one of the promising technology to dispose the waste effectively and possible way to generate electricity from the waste and value-added products. It is a thermal treatment to decompose different plastic and other carbonaceous waste into synthesis gas (syngas). Other components which can not be converted into syngas by thermal treatment can be found in the form of slag. This process is done in the absence of oxygen so the chances of oxide pollution in syngas are almost negligible. The generated syngas is made up of relatively non-condensable gases such as CO, H2, etc., and a small quantity of unburnt hydrocarbons. 0.5 TPD capacity thermal plasma pyrolysis plant was assembled at the Institute of Technology, Nirma University, Ahmedabad with the financial support of GUJCOST (GUJCOST/2020-21/880). There are different components such as belt conveyor, shredder, screw conveyor, plasma reactor, electrical source, cooling system (wet scrubber), mechanical filters (sawdust and fabric filter-based), 30 kVA IC engine coupled with generator and heat recovery system assembled. The preliminary runs were taken to check the compatibility of plastic and wood feedstock in the plasma pyrolysis reactor. Initially, five different ratios of wood and plastic feedstock were taken for the experimentation, and a flame test was carried out. Input conditions such as fuel flow rate, ampere, voltage of power source, etc. were kept constant. It was observed that plastic feedstock offered better performance in terms of gas quality as compared to wood feedstock. Then after, to check the compatibility of the MgCO3 catalyst, experiments were carried out with wood and different ratios of catalyst. It was observed that catalyst improves the overall quality of syngas. Mass balance was also carried out to identify the utilization of feedstock in the products. Overall, the plasma pyrolysis process with selected feedstock was successful and scope for generating electricity from syngas also.