Performance Analysis of a New Biomass-Based Polygeneration System for Power and Methanol

A new kind of biomass-based polygeneration system for the production of power and methanol is proposed in this paper. The most attractive feature of this proposed system is the elimination of shift process and the adoption of the partial recycling of unreacted synthesis gas (syngas). In this study, the thermodynamic performance of the system is examined and is then compared to those of two biomass-based reference individual systems, including the individual biomass to methanol system with the shift process (B-MS) and the biomass integrated gasification combined cycle (BIGCC). The influence of the recycling ratio of unreacted syngas (Ru), which determines the exergy ratio of the chemical product to power (γ), is also investigated. This paper further discusses a synergetic viewpoint of chemical conversion and energy utilization, with and without shift reaction and different treatments of unreacted syngas. Results show that the new polygeneration system can reduce energy consumption by as much as 10% compared with the reference individual systems. Moreover, the proposed polygeneration system is expected to realize the synergetic combination of chemical conversion and efficient utilization of bio-energy; hence, offering a possibility of developing new technologies for biomass-based systems.