Abstract
Carbon capture and storage (CCS) has long been regarded as an integral element of slowing global warming; both globally and locally in Taiwan. Although there have been much progress in capture, demonstration of successful storage is only found where there is opportunity in enhanced oil recovery. Therefore utilization has gradually received attention as an alternative to sequestration. Methanol has been demonstrated as a feasible primary feedstock to the chemical industry and offer enough scale as an option of utilization. However, the carbon reduction potential and the economic feasibility of CO2 to methanol transformation has been questioned. In this study, three options of producing methanol with CO2 were studied: (1) conventional methanol plants (2) dry reforming of liquid natural gas (LNG) + green hydrogen, (3) Bi-reforming which uses steam reforming of LNG for hydrogen generation. The three processes were analyzed by GH-Space and simulated by Aspen Plus software V8.4. The material cost and carbon emission were evaluated. The results show that while dry reforming offers a net carbon reduction, it has a high material cost due to the use of green hydrogen. Bi-reforming process offers no net carbon reduction by itself. However, it offers a cheaper alternative to produce methanol than the traditional steam reforming process, and produces much less carbon. Hence the bi-reforming process can considered as a profitable carbon reduction pathway by replacing existing methanol plants. Furthermore, critical elements of the process that can be modified to increase carbon reduction are identified.