The Bioenergy Conversion Characteristics of Feedlot Manure Discharging from Beef Cattle Barn

Abstract

This study was carried out to assess bioenergy conversion efficiency by biogas and solid fuel production in the cattle feedlot manure discharged from beef cattle barn. Feedlot manure was sampled from the cattle farmhouse located in Yong-in, Gyeonggi during the mid-fattening stage, periodically. The chemical characteristics, BMP (Biochemical methane potential) and HV (Heating values) of feedlot cattle manures were analyzed. Total solid contents of cattle feedlot manure were in the range of 29.98~44.28%, and volatile solid contents were in the range of 23.53~24.47%. In the anaerobic digestion of cattle feedlot manure, the methane production potential has increased from 0.141 to 0.187 Nm 3 kg -1 -VS added . The methane production of fresh cattle feedlot manure showed the range 0.141~0.187 Nm 3 kg -1 -Manure (average 0.047 Nm 3 kg -1 -Manure), the LHVs (lower heating values) of the produced methane were in the range of 316~560 kcal kg -1 -Manure (average 400 kcal kg -1 - Manure). In the direct combustion of fresh cattle feedlot manure, the LHVs were measured in the range of 747~1,271 kcal kg -1 -Manure (average 916 kcal kg -1 -Manure), and LHVs of solid fuel which have the water content of 20% were in the range of 2,694~2,876 kcal kg -1 -Manure (average 2,791 kcal kg -1 -Manure). Then, the drying energy of average 443 kcal kg -1 -Manure was consumed in the production of solid fuel which has a water content of 20%. Therefore, the direct combustion of cattle feedlot manure showed about 2.3 times higher LHV than the LHV of methane produced by anaerobic digestion. And LHV of solid fuel was about 6.0 times higher than the LHV of methane produced by anaerobic digestion. Then, the production of solid fuel presented more bioenergy conversion efficiency than the biogas production in the bioenergy use of cattle feedlot manure.