Numerical simulation and 4E analysis of a steam methane reforming-based multi heat recovery process, producing electricity, methanol, fresh water, heating, and coolant

Abstract

Natural gas power plants play a pivotal role in power generation; nevertheless, their waste heat contributes to diminished thermodynamic efficiencies and the release of carbon dioxide emissions. One primary approach involves implementing effective heat recovery strategies to generate various products. The present study suggests a novel approach to heat recovery in different stages utilizing series and parallel arrangements within an environmentally friendly design to enhance controllability while expanding the range of products. The present study includes a steam methane reforming process, a Kalina cycle, a multi-effect desalination unit, a methanol synthesis unit, two organic Rankine cycles, and two ammonia Rankine cycles. The primary objective of this system is to efficiently and concurrently produce electricity, hot water, chilled water, fresh water, and methanol. The findings reveal that the newly devised process exhibits energy and exergy efficiencies of 47.55% and 50.58%, respectively, while the total unit cost of products amounts to 7.69 $/GJ. From an environmental perspective, the results indicate that the proposed structure exhibits a total net emission of 87.1 × 103 kg/h and a CO2 footprint of 0.22 kgCO2/kWh. Ultimately, the economic assessment elucidates that the fixed investment cost, total investment cost, total annual cost, and net present value are equivalent to 373.0 M$, 496.1 M$, 207.5 M$, and 598.6 M$, respectively.