Energy Generation Potential Through Cattle Manure Solid Phase Gasification

Abstract

A common practice for cattle manure management, especially for farms with a small number of animals, is simply the separation of the manure solid phase from the liquid one and the subsequent spreading on the land. However, this biomass has a chemical composition similar to more valuable ones like woodchips, with the downside of the high ash content. For this reason, gasification of cattle manure solid phase in a small-scale gasifier was explored. Through this solution it is possible to provide both electrical and thermal energy to the farm, constantly throughout both the day and the year as opposed to other renewable sources like solar and wind power. In addition, a byproduct of this process is biochar, whose main application is in agriculture as soil improver and therefore it could be a valuable substitute of a fraction of the manure currently used as fertilizer. The quantity of manure available was assumed considering the typical size of an Italian dairy farm while the efficiency of the CHP system was calculated through an experimental test with a gasifier prototype. The results have been utilized for a basic comparison between the energy available through gasification and through anaerobic digestion.