Fuel gas production and plant nutrient recovery from digested poultry manure

Abstract

A pyrolysis/ashing process for poultry manure with the aim of recovering both the potential energy and the plant nutrients is proposed. Volatile compounds derived from the pyrolysis process were subsequently decomposed using a catalyst to produce light fuel gases, while the solid residues (char or ash) were applied to plant cultivation to examine their usefulness as fertilizers. During the poultry manure pyrolysis, the evolution of volatiles was found to occur at temperatures below 500℃ and the volatiles thus derived were effectively converted into light fuel gases by employing a commercialNi/Al2O3 catalyst. Steam addition promoted the water-gas-shift reaction and resulted in high yields of hydrogen. The plant nutrients nitrogen, phosphorus, and potassium were concentrated in the poultry manure char. Komatsuna cultivation tests demonstrated that this char represented a source of highly available nutrients and produced higher crop yields than conventional fertilizers. The porous structure of the poultry manure char was considered to be an important factor in terms of its function as a fertilizer.