Develpoment of low grade coal gasification technology by means of a high power microwave steam plasma torch

High power microwave plasma torch for coal gasification has been studied. For steam plasma generation, high pressure and temperature water vapor input to the three2.45 GHz microwave plasma torches. Fine coal powder (∼70 μm) was mixed with the steam plasma at the exit of the torch and supplied into the gasifier. The steam plasma and coal with additional oxygen were mixed and make a partial oxidation reaction (Oxygen to coal ratio is about 0.5∼0.6)at the high temperature(>1500°C)to generate the synthetic gas, such as CO and H2, in the gasifier. While the conventional coal gasification (IGCC: Integrated Gasification Combined Cycle) converts the high quality coal (>6,000 kcal/kg) into the synthetic gas at a high temperature and high pressure, use of the low grade(∼4000 kcal/kg) coal and operation at atmospheric pressure are an advantages of the plasma gasification. In this presentation, the developed25kWe steam plasma gasification system and numerical results for the design the gasifier will be discussed. The numerical simulation includes the several complicate models which are Gas-phase and Char reaction model, Turbulence model, Thermal radiation model and Discrete model, and solves the set of equations simultaneously.