EFFECT OF ASH CONTENT ON STEAM GASIFICATION OF HEAVY OIL FLY ASH

Abstract

The heavy oil fly ash (HOFA) generated from the oil-thermal power plants is usually disposed by landfill. However, HOFA contains a large amount of unburned carbon and heavy metal components, so that HOFA disposed as industrial waste was more costly than general waste. The steam gasification, which is expected to generate flammable gas, has attracted attention as an effective method of utilizing HOFA. When the steam gasification of HOFA at 700-800ºC was performed, H2, CO and CO2 were produced, and the amount of H2 evolution was the largest among these evolution gases. Furthermore, the amount of H2 evolution increased with increasing ash content in HOFA. In particular, the amount of H2 evolution with HOFA of 20 wt% ash contents was 179 mmol/g-char at 800ºC for 60 min. From XRD pattern of HOFA, iron oxide and nickel oxide were reduced before steam gasification. The amount of H2 evolution increased with increasing Fe and Ni contents in HOFA, suggesting that Fe and Ni species act as catalysts.