Prospects of Using Fly Ash as an Alternative to Commercial Complete-Oxidation Catalysts and an Automated System for the Determination of the Ash Activity

Abstract

The feasibility of converting local coal-fired boilers into environmentally friendly catalytic boiler plants using fly ashes as easily available complete-oxidation catalysts is demonstrated as a way of solving the environmental pollution problem. The technology of combusting organic fuels in a fluidized bed of heterogenous catalysts is briefly outlined, the principle of catalytic combustion is described, the feasibility of replacing special-purpose catalysts by fly ash is grounded, and the criteria that the fly ash has to meet are experimentally determined. The problems that result from introducing technology of combusting fuels in a fluidized bed of heterogenous catalysts are considered and ways of solving the latter are proposed. The unique compact specialized automated OXI-1 system developed by the authors is presented. The system allows for the catalytic activity of heterogeneous complete-oxidation catalysts to be promptly tested during the methane oxidation reaction by average-skilled personnel (laboratory assistants). Further, the system can be applied to explore the feasibility of using ashes, slurries, and slags containing catalytically active components as cheap and quite efficient complete-oxidation catalysts in fluidized-catalyst-bed boiler plants and combusting organic waste in reactors based on the same principle. According to a developed and tested method, comparative analysis of the catalytic activity of the fly ash from the boiler plant in Yurga, Kemerov oblast, and the commercial special-purpose IK-12-74 deep-oxidation catalysts for hydrocarbons was performed. The activity degree of the fly ash has been experimentally determined at different temperatures and the practicability of using the above fly ash within the range of 750–800°C has been grounded. Further, the minimum residence time of the fuel in the fluidized bed sufficient to maintain the catalytic combustion conditions has been found.