EMERGY AND EXERGY ANALYSES OF A BIO-BASED ECO-INDUSTRIAL PARK

Abstract

The recent development of biomass utilization systems to reduce the dependence on non-renewable resources is an effective strategy to achieve a sustainable solution. The evolution of bio-production requires industrial symbiosis strategies called ‘eco-industrial park’ to achieve lower pollution emission and resource consumption. The aim of this study is to provide a sustainability decision tool called emergy accounting analysis using MATLAB language which consists of two components; 1) the search of emergy pathways and 2) the computation of emergy flow. The algorithm has been validated and found to be accurate. Then, the algorithm was applied to a bio-based eco-industrial park model which was developed using ASPEN PLUS. Napier grass (Pennisetum purpureum) grown in Thailand was used as a representative feedstock. The main emergy support the cultivation were human labor resources and diesel consumption. The sustainability indicator (ESI) of the cultivation and the entire system were 0.29 and 0.10, respectively. The reason is that the industrial section relied on imported and non-renewable resources. The integrated biorefinery system with four main products (liquid fuels, methanol, steam and electricity) achieves higher performance in terms of the emergy compared to the existing alternative processes. Finally, emergy and exergy analyses were compared. The exergy analysis provides an insight view mainly on the efficiency of the specific process, while the emergy analysis gives a broader view of the resource supporting to the entire system.