Plasma gasification of solid fuels

Abstract

This paper describes numerical and experimental investigation of coal gasification in a combined arc-plasma entrained flow gasifier. Kazakhstan Ekibastuz bituminous coal of 40 % ash content, Germany Saarland bituminous coal of 10.5 % ash content and 14 % ash content bituminous coal from the Middleburg opencast mines, South Africa, were used for the investigation. Experimental investigations have been performed for Ekibastuz coal. Reactor power has been varied from 25 to 52.8 kWe. Plasma steam and air gasification of the coal has been compared. The numerical experiments were conducted using thermodynamic software codes TERRA and kinetic code PLASMA-COAL. It was shown that the synthesis gas concentration at the outlet of the gasifier reaches high values for all coals studied and varies in the range 96.4 - 98.7 %, whereas specific power consumption for the gasification process does not exceed 2.75 kW·h/kg. Regardless of the coal quality, its steam plasma gasification provides the high calorific value gas (4358 - 4555 kcal/kg) at the gas specific yield of 1.3 - 1.83 kg/kg.