High power plasma arc melting process for incinerated ash contraction

Abstract

A new process to reduce the volume of the incinerated ash and to make the ash harmless and recyclable has been developed using a high power plasma arc system. The experiments have been done in the Structure Research Laboratories of Kawasaki Steel Corporation in Chiba City using the pilot plant of which the melting efficiency of ash is 200kg/h and the maximum power of plasma is 240KW. The energy and material balances of this process were made clear by the experiments. Melting process metamorphoses ash to granulated slag which is reduced to one-third in its volume with no toxic problems. The slag is available for construction materials. A new operation method in a reducing atmosphere has been also developed to depress the NOx content in exhaust gas which is evolved in the plasma gas. The reduction of collimator diameter of plasma torch to prevent the erosion of copper electrode achieves remarkable prolongment of its lifetime. © 1994, Walter de Gruyter. All rights reserved.