(404d) Investigation on CO2 co-Gasification of Horticultural Waste and Sewage Sludge for Energy Production: Effects of Temperature, Ash Content and CO2 flow Rate

In this work, a fixed-bed downdraft gasification system is used to harvest the energy from the municipal solid wastes, i.e. horticultural waste and sewage sludge. In comparison with conventional disposal route of horticultural waste and sewage sludge, e.g. incineration and air gasification, CO₂ gasification is known to be more environmentally friendly with the ability of CO₂ capture, fewer pollutant emissions and the produced synthesis gas in this process can be eventually utilized in boilers, gas engines or turbines to generate electricity or easily upgraded to transportation fuels through some chemical processes. Sewage sludge with high ash content is co-gasified with horticultural waste in this work in order to enhance the overall heating value of the feedstock and avoid agglomeration in real operation. In addition, the alkali metal content in the horticultural waste was reported to act as a catalyst for gasification, thus this co-gasification can help achieve high solid-to-gas conversion efficiency. The effects of operating parameters of a fixed-bed downdraft gasification system, i.e. temperature (700-900°C), ash content (5-25%) and CO₂ flow rate (60-100mL/min), on the gasification performance have been comprehensively studied through the Box–Behnken experiment design.