Title: Kinetic and thermodynamic modelling studies of enhanced mixed animal wastes biomethanisation co-digested with pineapple fruit waste and chicken rumen

Authors: Oluwafunmilayo A. Aworanti; Samuel E. Agarry; Oladipupo O. Ogunleye

Addresses: Department of Chemical Engineering, Biochemical and Bioenvironmental Engineering Laboratory, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Nigeria ' Department of Chemical Engineering, Biochemical and Bioenvironmental Engineering Laboratory, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Nigeria ' Department of Chemical Engineering, Product and Process Development Laboratory, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Nigeria

Abstract: This work evaluated the effects of feed/inoculums ratio, temperature and agitation speed on biomethanisation of the mixture of cattle dung, pig dung, and poultry droppings for enhanced biogas/biomethane production. The biomethanisation experiments were carried out in anaerobic digesters at different process variables of feed/inoculums ratio (1:1, 1:2, 1:3, 2:1 and 3:1), temperature (25-60°C), and agitation speed (30-70 rpm). The digesters were incubated for 70 days. The results showed positive influence of feed/inoculum ratio, temperature and agitation speed on cumulative biogas yield, biomethane content and start-up time of biomethanisation. Modified Gompertz and Exponential Rise to Maximum kinetic models showed better correlation of the cumulative biogas production. The estimated values of the thermodynamic properties (Gibbs free energy, enthalpy, entropy change and activation energy) suggested that the biomethanisation process was thermodynamically feasible, spontaneous and endothermic in nature suggesting hydrogenotrophic methanogenesis pathway.

Keywords: animal waste; biogas; biomethane content; process variables; kinetics; thermodynamics.

DOI: 10.1504/IJRET.2018.095793

International Journal of Renewable Energy Technology, 2018 Vol.9 No.4, pp.393 - 415

Accepted: 07 Feb 2018
Published online: 11 Oct 2018 *

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