Thermodynamic evaluation of CCHP system based on biomass gasification by exploring the feasibility of using CO2 as gasification agent

• Published in: Sustainable energy technologies and assessments 2020-12, Vol.42, p.100867, Article 100867
• Main Authors: Li, Songzhao, Zhu, Lin, He, Yangdong, Fan, Junming, Lv, Liping
• Format: Article
• Language: English
• Subjects: Biomass; CCHP; CO2 utilization; Exergy analysis
• ISSN: 2213-1388
• DOI: 10.1016/j.seta.2020.100867

•Trigeneration system based on CO2-agent biomass gasification is proposed.•Energy, exergy and economic analysis of proposed system are performed.•Optimum gasification temperature and CO2/C have been obtained. The initial purpose of adopting combined cooling heating and power (CCHP) system is to achieve cascade utilization of fuel energy as well as stepping into low-carbon society. In this study, CO2 is used as gasification agent instead of conventional option of using steam in the biomass gasification unit for reducing CO2 emissions and increasing energy efficiency. To determine the thermodynamic feasibility during the process, exergy analysis has been performed within the whole process as well as its individual units. From the analytical results, it discloses that gasification and combustor irreversibilities yield the highest exergy destruction in the CCHP system, which account for 44.19% and 20.79% of the overall exergy destruction, respectively. Exergy analysis emphasises that both losses and irreversibilities can contribute to loss of efficiency system performance. Additionally, focusing on the influences of key parameters on system performance has been highlighted as well. The outcomes suggest that the optimum gasification temperature and CO2/C are 825 °C and 0.25 respectively. Under the optimal design parameters, the energy efficiency and PESR can reach 53.25% and 10.17% in summer respectively. In addition, a preliminary economic analysis is involved and the financial feasibility of this CCHP system is further demonstrated.