Experimental Research of the Oxygen-Enriched Combustion of Sewage Sludge and Coal in CFB

Abstract

Sewage sludge is the by-products of sewage treatment, and it is a fuel of high moisture, high ash and low caloric. Oxygen-enriched combustion technology is one of the new and clean coal combustion technologies that can control pollutant emission, which makes CO2 separation, SO2 treatment become easier, and NOx emission reduced. In this paper, we carried out the experimental research on the advantages of oxygen-enriched combustion and the characteristics of sewage sludge in a CFB incinerator that the diameter of the furnace is 100 mm, It is an important foundation for the industrialized application of the oxygen-enriched combustion of sewage sludge and coal in CFB. Experimental analyzed on the combustion characteristics of three conditions in the oxygen concentration of 21%∼35%, which were the weight ratio of coal and sludge were 1∶1, 1∶2 and also the coal was given. Furthermore, the change of gas composition along with the change of oxygen content and the temperature of dense phase region was analyzed. The results showed that the combustion characteristics differ from the different mixing rate between coal and sludge in different oxygen atmosphere, when the fluidized air velocity was 1.56 m/s∼1.88 m/s, the combustion stability; When the amount of the fuel was constant, as the increase of the oxygen contents in the experimental atmosphere, the total air volume decreased, the furnace temperature increased gradually, the concentration of SO2 and NOx showed increasing trend, which is beneficial to the removal of SO2; The concentration of NOx was increased gradually as temperature of the fluidized bed increased.