Gasifi cation of carbon–contaning waste in a plasma–chemical reactor

Abstract

The results of thermodynamic calculations and experiments on plasma gasification of solid carbon containing wastes are presented using the example of medical and sanitary wastes, which showed the promise of using the plasma-chemical waste processing technology to produce combustible gas and inert mineral material. The TERRA universal computer program for calculating multicomponent heterogeneous systems was used for thermodynamic calculations. Its base of thermodynamic properties contains about 3000 substances in the temperature range of 300–6000 K. The optimum waste gasification temperature T = 1600 K is found, at which the maximum concentration of synthesis gas of 82.6 vol.% (СO – 31.7, H₂ – 50.9) is reached. The experiments were carried out in a plasma-chemical reactor equipped with a 70 kW plasma torch with waste capacity of up to 30 kg/h. In the process of plasma air gasification of medical-sanitary waste at 1600 K, synthesis gas was obtained with concentration of 71.1 vol.% (H₂ – 44.6, CO – 26.5) and a light gray solid inert residue. Comparison of plasma gasification and conventional waste incineration methods shows the higher energy effi ciency of plasma technology. As a result of plasma gasifi cation of waste, a combustible gas with thermal power of 430 MJ/h is obtained. When they are burned, an inert gas (CO₂, H₂O и N₂) is formed with physical heat of 145 MJ/h. Thus, the useful thermal power of plasma gasifi cation products is three times higher than that at waste incineration. Comparison of the results of the experiment and calculations showed their satisfactory agreement. Both in calculations and in experiments, no harmful impurities were found in the products of plasma gasifi cation of waste.