Process design and thermoeconomic evaluation of a CO2 liquefaction process driven by waste exhaust heat recovery for an industrial CO2 capture and utilization plant

TLDR: In this article, the potential of using excess heat in the main industrial CO2 capture and utilization plant of Iran is investigated, and a CO2 liquefaction cycle is developed using the heat waste of the flue gas.

Abstract: Industrial surplus heat is a great available source and because of potential for external use can create benefits for society and industry. Utilizing surplus heat can deliver a way to decrease the use of primary energy and to play a part in global CO2 mitigation. The potential of using excess heat in the main industrial CO2 capture and utilization plant of Iran is investigated. A CO2 liquefaction cycle i.e., ammonia-water absorption system is developed using the heat waste of the flue gas. Process modeling is developed in Aspen Hysys™ v.10 software with the aid of Peng-Robinson equation of state. Energy, exergy, economic and exergoeconomic analyses are then employed to evaluate the developed CO2 liquefaction cycle integrated into the carbon capture and utilization plant. Results of process design and simulation show that the developed CO2 liquefaction system can liquify CO2 with the capacity of 54.5 tons per day using the flue gas enthalpy. The developed CO2 liquefaction system has the COP of 0.28, and overall exergy efficiency of 69.7%. The highest amount of exergy is destructed in ammonia reboiler with the amount of 281.92 kW. Exergoeconomic results reveal that the compressors in CO2 compression unit along with ammonia absorber and stripper have the highest importance among equipment.