Energy, exergy, exergoeconomic and exergoenvironmental analysis and optimization of quadruple combined solar, biogas, SRC and ORC cycles with methane system

The present work deals with a novel configuration of four cycles such as steam gas cycles and an organic Rankine cycle and a biogas Brayton cycle and a solar Brayton cycle are introduced for recovering energy from hot exhaust gas and its simulation and optimization are discussed. Also, a carbon-amine adsorption system has been utilized for separating and storing carbon dioxide from hot exhaust gases and convert it to methane. For this new system, exergy, economical exergy, energy, economic and environmental exergy evaluations have been performed. To analyze the different parts, their thermodynamic and economic models, EES and MATLAB software have been used to optimize the exergy-economic cycle in order to reduce costs and increase exergy. In this research, genetic algorithm has been used for optimization. At the optimal point, the values of exergy efficiency are equal to 61.7% and the cost of electricity generation is 6.36 cent per kilowatt hour. The results show that adding Rankine cycles to the gas cycles increments the exergy and energy efficiency to 73.7 and 71.8, respectively. Nevertheless, integrating the carbon capture unit with this system reduced the exergy and energy efficiency to 51.9% and 50.5%, respectively. Based on the economic results for the presented system, it is indicated that the simple return on investment and return on investment are both 1.5 years. In addition, internal rate and net present value of return were 0.68 and 3.13*09 $ respectively. This system can generate 327,160 kW of electricity in addition, the carbon capture system unit can prevent and convert 627,000 tons of carbon dioxide into methane fuel annually.

Automated summary

This study introduces a novel energy recovery system that combines different cycle structures to recover energy from hot exhaust gases and convert carbon dioxide for further utilization. The optimized system achieved a exergy efficiency of 61.7% and can generate a significant amount of electricity and methane fuel.