Investigation of thermal integration between biogas production and upgrading

•Identify thermal characteristics of amine-based biogas upgrading for waste heat recovery.•Identify thermal characteristics of AD biogas production as sink for heat recovery.•Evaluation of thermal integration between biogas production and upgrading to improve overall energy efficiency.•Cost analysis applied for the economic feasibility of the thermal integration.•Using the principles of target design and system integration for connected thermal processes. Thermal integration of anaerobic digestion (AD) biogas production with amine-based chemical absorption biogas upgrading has been studied to improve the overall efficiency of the intergraded system. The thermal characteristics have been investigated for industrial AD raw biogas production and amine-based chemical absorption biogas upgrading. The investigation provides a basic understanding for the possibilities of energy saving through thermal integration. The thermal integration is carried out through well-defined cases based on the thermal characteristics of the biogas production and the biogas upgrading. The following factors are taken into account in the case study: thermal conditions of sub-systems, material and energy balances, cost issues and main benefits. The potential of heat recovery has been evaluated to utilise the waste heat from amine-based upgrading process for the use in the AD biogas production. The results show that the thermal integration has positive effects on improving the overall energy efficiency of the integrated biogas plant. Cost analysis shows that the thermal integration is economically feasible.