Alkali Separation in Steam Injected Cyclone Wood Powder Gasifier for Gas Turbine Application

Abstract

Cyclone gasification of wood powder at atmospheric pressure has been studied. The cyclone gasifier works as a particle separator as well and the wood powder is injected into the cyclone with air or air/steam as transport medium. The effects of stochiometry and steam injection on the gasification temperature and separation of char particles are investigated. The experimental results are compared with theoretical predictions. The amount of Potassium (K) and Sodium (Na) that can be separated together with the char is also studied since this is of special interest if the gas is used to operate a gas turbine. The fuel flow has been 26 kg/h corresponding to a thermal input of 140 kW. The equivalence ratio was varied between 0.15 and 0.4. Wood powder has been injected with air only or air/steam with steam mass flows of 50–80% of the fuel flow. It has been possible to separate 20–40% of the potassium and 10–20% of the sodium supplied with the wood. The resulting alkali content in the gas entering a turbine at a temperature of 850°C is between 4 and 8 mg/kg gas.