Influence of Co-pyrolysis Conditions on Characteristics of Char Produced from Dried Sludge and Coal

Abstract

In recent years, co-firing and co-gasification using sludge and coal has been carried out for utilizing sewage sludge as new energy. In co-pyrolysis process on co-gasification and co-carbonization, clarifying the characteristics of char produced from sludge and coal is important. Because it is assumed that the reaction between char and pyrolysis gas will be occurred by blending both raw materials. So, we conducted co-pyrolysis experiments changed temperature, sample ratio and coal kind, and investigated the influence of co-pyrolysis conditions on char yield and surface area of co-char produced from sludge and coal by comparing with the characteristics of single char produced from a raw material. As a result, yield of co-char increased more than that of value added single chars, and pore surface area of co-char decreased more than that of value added single chars. In the case of using another kind coal in co-pyrolysis experiment, char yield, carbon ratio and heating value of co-char increased more than values added single chars. However, there is no difference of raman spectrum between co-char’s and single char’s. So, we revealed that char yield, pore surface area and element ratio of co-char produced from sludge and coal were not expressed by adding single char characteristics produced from a raw material. And mixing both materials during pyrolysis affected the characteristics of char.