Pyrolysis and ignition behavior of coal, cattle biomass, and coal/cattle biomass blends

Increases in demand, lower emission standards, and reduced fuel supplies have fueled the recent effort to find new and better fuels to power the necessary equipment for society?s needs. Often, the fuels chosen for research are renewable fuels derived from biomass. Current research at Texas A&M University is focused on the effectiveness of using cattle manure biomass as a fuel source in conjunction with coal burning utilities. The scope of this project includes fuel property analysis, pyrolysis and ignition behavior characteristics, combustion modeling, emissions modeling, small scale combustion experiments, pilot scale commercial combustion experiments, and cost analysis of the fuel usage for both feedlot biomass and dairy biomass. This paper focuses on fuel property analysis and pyrolysis and ignition characteristics of feedlot biomass. Deliverables include a proximate and ultimate analysis, pyrolysis kinetics values, and ignition temperatures of four types of feedlot biomass (low ash raw manure [LARM], low ash partially composted manure [LAPC], high ash raw manure [HARM], and high ash partially composted manure [HAPC]) as well as blends of each biomass with Texas lignite coal (TXL). Activation energy results for pure samples of each fuel using the single reaction model rigorous solution were as follows: 45 kJ/mol (LARM), 43 kJ/mol (LAPC), 38 kJ/mol (HARM), 36 kJ/mol (HAPC), and 22 kJ/mol (TXL). Using the distributed activation energy model the activation energies were 169 kJ/mol (LARM), 175 kJ/mol (LAPC), 172 kJ/mol (HARM), 173 kJ/mol (HAPC), and 225 kJ/mol (TXL). Ignition temperature results for pure samples of each of the fuels were as follows: 734 K (LARM), 745 K (LAPC), 727 (HARM), 744 K (HAPC), and 592 K (TXL). There was little difference observed between the ignition temperatures of the 50% blends of coal with biomass and the pure samples of coal as observed by the following results: 606 K (LARM), 571 K (LAPC), 595 K (HARM), and 582 K (HAPC).