Analysis and economic evaluation of a unique carbon capturing system with ammonia for producing ammonium bicarbonate

Carbon capturing is recognized as an essential solution for reducing greenhouse gas emissions, particularly produced by thermal power plants. The main disadvantage of the existing capturing technologies is the high capital and operating costs. This study presents a thermodynamic analysis of an ammonia-based carbon capturing system to produce ammonium bicarbonate as a valuable commodity to offset the high costs of carbon capturing. This system uses a renewable energy source to supply the power required for the carbon capturing system. A thermodynamic model of the carbon capturing system is established using the energy and exergy approaches. The results of the modeling work show that the present system offers a high carbon capturing efficiency of 95.5%, but the energy requirements are substantially high at a value of 14.3 MJ kg (1) of carbon dioxide captured. The exergy analysis of this system shows that the proton-exchange membrane electrolyzer produces 88.3% of the total exergy destruction rate at a value of 1.99 kW when the carbon capturing system receives 5 kW of power input. The designed system is for a pilot-scale application. Even though the energy requirements are high, the value generation rate of this system can reach as high as C$158 in one hour of operation compared to typical carbon capture systems that have energy penalties that cause losses instead of economic gains. This study demonstrates the economic potential of using carbon capture systems that co-produce useful chemicals to not only compensate for the operation costs of carbon capturing but generate value in the process.

Automated summary

This study presents a thermodynamic analysis of an ammonia-based carbon capturing system that produces valuable commodities to offset the high costs of carbon capturing. Despite the high energy requirements, the system has the potential to generate economic value.