Experimental and numerical study of biogas, methane and carbon dioxide produced by pre-treated wheat straw and pre-digested cow dung

摘要

The biogas constituting majorly CH_4 and CO_2 has been produced by Ca(OH)_2 pre-treated wheat straw with pre-digested cow dung. Some of the key thermodynamic parameters like specific heat capacity, density and heating capacity of the biogas produced have also been calculated per day as well as throughout the hydraulic retention time. The governing equations of biogas with appropriate phase and interfacial conditions describing the physics of the biogas have been derived. The control volume approach has been used to predict the total volume (ml) of biogas, CH_4 and CO_2 throughout the experiment and on the daily basis. The effects of feedstock, temperature and pressure on the production of biogas, CH_4 and CO_2 in anaerobic digestion have also been studied. The average number of molar fraction and conversion ratio of CH_4 and CO_2 are correlated with number of carbon atoms available in feedstock. Numerical calculations by using developed model and Modified Gompertz model have shown proficient agreement with the experimental observations.