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Abstract
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Bio-methanol and bio-methane are flexible fuels that are easily stored and considered as a sustainable alternative energy source due to high octane numbers. In particular, herein biogas is used as a potential fuel for producing bio-methanol and bio-methane. Biogas is mainly composed of methane (CH4) and carbon dioxide (CO2). In this paper, a novel integrated system consists of a biogas upgrading process to pure bio-methane production, a bio- methanol synthesis unit, an alkaline electrolysis unit to produce hydrogen, an organic Rankine cycle (ORC) for power generation, an ammonia/water absorption refrigeration cycle (ARC) for cooling production, and a parabolic trough solar collectors (PTSCs) system is introduced and thermodynamically assessed. Co-generation of bio-methanol and bio-methane results in CO2 emissions reduction. ASPEN HYSYS, TRNSYS, and MATLAB soft-
ware were used for the simulation of this integrated system. For the simulation of PTSCs, the geographical location of Bandar Abbas with a longitude 56.26◦ and latitude 27.17◦ was used. The proposed structure produces 128.4 kgmole/h bio-methanol with a purity of 99.99% and 193.4 kgmole/h bio-methane with a purity of 99.65% as the main products, and also, 2783 kW cooling and 241,930 kgmole/h domestic hot water as by-products. The PTSCs system provides 314.5 MW thermal energy for the ORC. The required hydrogen for bio-methanol synthesis is provided by an alkaline electrolysis unit, which generates 200 and 400 kgmole/h O2 and H2, respectively. The energy, exergy, and parametric analyses were conducted to assess the thermodynamic performance of the pro-
posed system. The overall energy and exergy efficiencies of the integrated system are 92.47% and 45.92%, respectively. The results of the exergy evaluation revealed that the lowest exergy efficiency and the largest exergy destruction rate is related to the PTSCs system with values of 60.03% and 88867.08 kW, respectively. Moreover, at the design condition, the ener
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