Gasification of Dairy Manure
The feasibility of gasifying, rather than digesting, dairy manure was examined by Skill Associates, of Kaukauna, Wisconsin. Gasification of some waste biological materials, such as wood chips, is feasible. However, the moisture content of dairy manure is typically 87% by mass, too high to gasify. Therefore a drying process must be introduced in order to lower the moisture content to at or below 40%, the break-even point in the energy cost of drying. The Skill Associates process, which is more accurately described as manure burning, incorporates extensive manure drying facilities and mechanical sand separation. The cost estimated for the system was $1.7 million (much higher than the digester system) with a payback period of 9.4 years and was considered infeasible by the CBG when compared to our available funds.
Despite these conclusions, manure from Fisher Dairy has been sent to North Carolina State University to be experimentally gasified. The results of this work will contribute information on the energy costs of gasifying wet manure.