Thermoeconomic Analysis and Optimization of Post-combustion CO_2 Recovery Unit Utilizing Absorption Refrigeration System for a Natural-Gas-Fired Power Plant

摘要

Exergy and exergoeconomic analyses have been used to set out weaknesses of the postcombustion CO_2 capture unit of Besat power plant that uses an ammonia absorption refrigeration system for CO_2 liquefaction. The energy required for the absorption system is provided by the flue gas. The liquefied CO_2 is used for beverage and food industries. The exergoeconomic costs of all utility streams and processes are calculated through a systematic method of assigning exer-getic cost relations to the streams. 'The results point out that the exergy destruction of the CO_3 stripper and absorber columns are the highest, and according to the cost-based information, potential locations for the process improvement are proposed. A comprehensive method based on thermodynamic and mathematical methods has been proposed to acquire efficient design parameters and consumed power in compressors. It is based on a combination of Aspen HYSYS~® and MATLAB~® to do calculations and then an optimization procedure based on genetic algorithms. Results show that the production cost of each ton CO_2 is equal to 6.05 (USD/ton) and return on investment can also be obtained by 2.5 years considering USD 1,600,000 of annual revenue.