Synergy in Syngas Yield From Co-Pyrolysis of Cow and Chicken Manures

Abstract

Manure waste from dairy, livestock, and poultry industries can pose significant challenges in their disposal due to their odor, nitrogen, phosphorous, and heavy metals contents, and pathogens. Existing disposal techniques like anaerobic digestion, although can provide biogas with energy output, is a slow process with significant carbon loss to CO2 and can also result in leaching. High-temperature pyrolysis can convert these wastes into syngas along with biochar which can be used for various applications. Thermochemical conversion needs to be feed-flexible, and operating it with manures from various animal sources such as poultry and dairy sectors can provide sustained operation, intensified process, and improved conversion throughput. So, we examined high-temperature co-pyrolysis of chicken and cow manures to understand the influence of their mixture fractions on the syngas components and char yield. Lab-scale semi-batch co-pyrolysis was carried out for cow and chicken manures at 900 °C with mixture fractions varying from 0 to 100%. Syngas analysis from these tests revealed the presence of synergistic enhancement of its components and in terms of syngas energy yield and carbon conversion, a 2:3 ratio of cow to chicken manure resulted in the most enhancement compared to the expected aggregate of pyrolyzing cow and chicken manures separately. This paper provides a detailed analysis of these syngas components from co-pyrolysis in comparison with separate pyrolysis to explore the advantages of blended feedstock toward an efficient, clean, and feed-flexible pathway for manure waste disposal and utilization.