Gas system cascade analysis framework for optimal design of biogas system

Abstract

The main objective of this research is to develop a new framework called Gas System Cascade Analysis (GASCA) based on Time-Based Pinch Analysis (TBPA) principle. In additional, there are 4 sub-objectives in this study which is to determine the optimal capacity (energy equivalent) of anaerobic digester (AD) and biogas storage, to examine the impacts of supply-demand variation in selected region, to evaluate the impact of incorporating biogas system on carbon emission reduction and to estimate the cost-benefit analysis for biogas system. Prior to applying GASCA framework, the superstructure of biogas distributed energy system design is introduced to show the overall system operational scenario followed by data collection and extraction. The TBPA was then conducted to determine the optimal capacity of AD, biogas storage, and operation (charging and discharging of biogas from biogas storage). Based on the case study, the optimal capacity of AD was 4,629.52 MJ/h with maximum energy capacity at biogas storage of 16,988.61 MJ/h. Sensitivity analysis was conducted to examine the impact of supply-demand variation on the capacity of AD and biogas storage. The carbon emission reduction contributed by the proposed framework was up to 131,011 kg CO2eq per day. For cost-benefit analysis, the calculated Net Present Value was 18.73 %. In conclusion, GASCA framework has been applied successfully to determine the optimal capacity (energy equivalent) of AD and biogas storage.