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Coal gasification, the major approach to coal-based chemicals synthesis, suffers from substantial carbon dioxide emission. Reducing CO 2 emission is the emphasis and hotspot in coal chemical industry. On the other hand, the traditional coking process is inefficiency of carbon and hydrogen resources utilization. For higher coal resource utilization and lower carbon emission, this paper proposes a novel methanol production process from coal gasification integrated with coal coking. This process consists of the units of coal gasification, coking, coke gasification, dry methane reforming, and methanol synthesis. Coke gasification transforms the low-valued coke to high-valued chemicals and makes the process suitable for market variation. DMR converts methane and CO 2 into syngas, increasing the overall resource utilization efficiency. This integrated process has the advantages of higher valued products and larger methanol productivity. According to the simulation and detailed techno-economic analysis, the new process has a much higher carbon utilization efficiency of 51.6%, compared to 37.3% of the single coal to methanol (CTM) process, and the corresponding CO 2 emission is reduced by 34.6%. The energy efficiency of the CGCTM process is 62%, which is about 21.6% higher than that of CTM process. As for economic benefits, the internal rate of return for the new process is 22.5%, much higher than 15.3% of the current CTM process. • An integrated process of coal gasification and coking to methanol production was proposed. • The new process is suitable for market variation and can enhance the flexibility of the system. • The new process has much higher carbon utilization efficiency and lower CO 2 emission. • The new process will show the economic advantages in the era of high carbon tax. [ABSTRACT FROM AUTHOR]

Over recent years there has been a significant increase in the amount of technology contributing to lower emissions of carbon dioxide. The aim of this paper is to provide a comparison between two technologies for methanol production, both of which use carbon dioxide and hydrogen as initial raw materials. The first methanol production technology includes direct synthesis of methanol from CO 2 , and the second has two steps. During the first step CO 2 is converted into CO via RWGS (reverse water gas shift) reaction, and methanol is produced during the second step. A comparison between these two methods was achieved in terms of economical and energy-efficiency bases. The price of electricity had the greatest impact from the economical point of view as hydrogen is produced via the electrolysis of water. Furthermore, both the cost of CO 2 capture and the amounts of carbon taxes were taken into consideration. Energy-efficiency comparison is based on cold gas efficiency, while economic feasibility is compared using net present value. Even though the mentioned processes are similar, it was shown that direct methanol synthesis has higher energy and economic efficiency. [ABSTRACT FROM AUTHOR]

This paper presents a thermochemical process design and techno-economic analysis for the production of methanol (MeOH) from Kenaf cultivated in Korea. The proposed process combines three main subsystems to allow for the processing of 2000 tons of kenaf a day: kenaf-to-syngas, syngas-to-MeOH, and a combined heat and power cycle. In the first subsystem, clean syngas is produced from kenaf via a two-step carbonization and steam gasification process. The clean syngas is then catalytically upgraded to MeOH using a commercial Cu/ZnO/Al 2 O 3 catalyst. The third subsystem allows for the generation of heat and electricity to close the energy balance by combusting the biomass residues. Energy analysis and optimization of the heat exchanger network allowed for all energy requirements to be satisfied internally, high overall energy efficiency (60.6%), and the selling of 3.3 MW of excess electricity. Furthermore, an economic feasibility analysis of the process showed that the minimum selling price of MeOH (99.9 wt%) was 0.413 US$/kgMeOH. Importantly, the process economics could be in the range of the market price with respect to incorporating different types of H 2 production technology into the process. • Green methanol production is a promising technology to convert Kenaf. • A process including a two-step of gasification and catalytic upgrading is designed. • Economic feasibility is evaluated by considering process scale. • Sensitivity analysis identify the relative significance of the major key parameters. [ABSTRACT FROM AUTHOR]

Power-to-methanol processes with co-electrolysis in solid-oxide electrolyzer provides a promising approach to deal with two problems: large-scale renewable electricity storage and carbon capture and utilization. In this paper, a large-scale power-to-methanol system with solid-oxide electrolyzer co-electrolysis technology is studied. System-level heat integration and techno-economic assessment are performed by using a multi-objective optimization platform. The results indicate that there is a slight trade-off between the overall energy efficiency and methanol production cost. The system can achieve a high energy efficiency (72%) and carbon conversion efficiency (93.6%), with the annual CO 2 utilization reaching 146.7 kton. However, its economic cost is high. SOE stack price, stack lifetime, and electricity price are crucial to the economic competitiveness of the system. By reducing the cost of SOE stack, extending its lifetime and reducing electricity price, the payback time can be shortened to 3–5 years. A stable supply of renewable electricity is necessary for the project investment. When the annual available hours of renewable electricity drop from 7200 to 3600, the payback time of the project increases to 21 years. Methanol synthesis with SOE co-electrolysis has an outstanding heat integration performance. The system can recover heat in a Rankine cycle to enhance the overall energy efficiency. • Power-to-methanol with co-electrolysis in SOE is investigated techno-economically. • The system achieves a higher system energy efficiency (72%). • The SOE is more suitable to low-pressure operation to avoid internal methanation. • The optimized system has perfect overall heat integration property. • Availability of renewable electricity are a prerequisite on the economic feasibility. [ABSTRACT FROM AUTHOR]

This study proposes an innovative methanol production process from landfill gas (LFG) through direct CO 2 hydrogenation and methane (CH 4) reforming. The integration of two methanol production routes from CO 2 and CH 4 enables the full upcycling of carbon sources in the LFG into methanol, as compared to conventional processes that utilize only CH 4 as a carbon source. The optimal process configurations and operating conditions of two LFG-to-methanol processes (L2M), stand-alone (L2M-SA) and with hydrogen supply (L2M−HS), are proposed by developing rigorous process models with the aid of sequential quadratic programming optimization. The capability of the processes is analyzed using four evaluation metrics: carbon and energy efficiencies, net CO 2 emission, and unit production cost (UPC). It was observed that the carbon and energy efficiencies of both the L2M processes could reach up to 92% and 69%, respectively. The methanol UPC is estimated in the range of 392–440 USD/ton, which is competitive against other renewable and conventional methanol production options. In addition, the CO 2 emission (0.83 and 1.29 kg of CO 2 per kg of MeOH of the L2M−HS and -SA, respectively) implies that the full upcycling of LFG to methanol is not only economically viable but also an environmentally clean strategy. • New green methanol production processes from a landfill gas are proposed. • Methane reforming and CO 2 hydrogenation are integrated for full-upcycling of landfill gas. • The optimal operating conditions for maximizing methanol production are identified. • The processes show improved energy efficiency, CO 2 emission and competitive economics. [ABSTRACT FROM AUTHOR]