Thermodynamic analysis of trigeneration system with controlled thermal-electric ratio by coupling liquefied natural gas cold energy and biomass partial gasification

Efficient utilization of biomass energy is crucial for addressing environmental challenges. However, the low calorific value of syngas from biomass gasification poses subsequent utilization issues. This study proposes a trigeneration system integrating biomass partial gasification and LNG cold energy to address surge problems using syngas combined cycle systems. The design includes air separation units, combined cycle, and biomass gasifier, achieving an adjustable thermal-electric ratio. An air separation unit and two-stage Organic Rankine Cycle fully utilize LNG cold energy. A thermodynamic model was established in Aspen Plus, and energy, exergy, and economic analyses were conducted to assess feasibility, followed by a sensitivity analysis. Results show that with a mix burning ratio and carbon conversion rate of 0.6 and 0.7, the system's exergy, energy, and electrical efficiencies are 36.94 %, 60.14 %, and 33.32 % in cooling mode. The unit exergy cost and CO2 emissions are 0.0748$ and 95.29 kg/s, respectively. Analysis reveals variations in efficiency and outputs with changes in mix burning ratio and carbon conversion rate. Adjusting operational parameters enhances the system's ability to regulate the thermal-electric ratio, demonstrating its potential for efficient biomass energy utilization and environmental sustainability.