Zhu, He; Lin, Yutong; Tian, Jing; Li, Zhichao; Zhang, Yidan; Li, Shuqing; Sun, Yuhan; Zhang, Jun

CHEMICAL ENGINEERING JOURNAL

2025, ,

Zhu, He; Lin, Yutong; Tian, Jing; Li, Zhichao; Zhang, Yidan; Li, Shuqing; Sun, Yuhan; Zhang, Jun

Using industrial tail gas and renewable energy for large-scale methanol production has emerged as a viable pathway to reduce CO2 emissions significantly, garnering substantial attention in recent years. While some emerging technologies have been successfully applied commercially, advanced concepts continue to appear to improve CO2 emissions and techno-economic performance. This study compares four processes: three tubular flow reactor (TFR) based processes (CT-1: coke oven gas (COG) alone; BT-2: biogas (BG) alone; CBT-3: COG+BG) and an autothermal-reforming (ATR)-reactor-based process (CB-A: COG+BG). The CB-A process innovatively integrates CH4-CO2 ATR by coupling hydrogen-rich COG and carbon-rich BG from manure fermentation, eliminating CO2 emissions from external combustion, enabling closed-loop CO2 recovery from feedstock, and optimizing the H/C ratio for methanol synthesis. Validated process modeling reveals that the CB-A process achieves a carbon efficiency of 91.6 % and net energy efficiency of 84.8 % (including 18.8 % as a utility), which approaches the state-of-the-art in this research domain. Compared to three conventional tubular flow reactor routes, the CBA process increases hydrogen efficiency (78.8 %) and exergy efficiency (74.6 %) by 3-36 % and 3-21 %, respectively, while reducing equivalent CO2 emission to 1.2575 tCO2 e.q./t (21-37 % lower). The unit product cost of methanol is $174.63/t, below China's methanol market price over the past decade ($215-500/t). These superior performances confirm CB-A as the preferred route, representing an economically and environmentally superior technology that offers critical insights into synergistic integration of coal-chemical and biomass energy systems to advance waste-to-energy low-carbon industrial practices.