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This work proposes a novel zero–CO 2 –emission energy system to meet thermal and electrical energy needs of the cities without emitting CO 2 while using natural gas as a primary energy source. Since the system uses available technologies, it is envisioned as a part of transition towards net-zero sustainable economy. At the core of the system is production of hydrogen via pyrolysis of methane which has recently achieved technological maturity of industrial scale production. Natural gas combustion in a combined heat and power (CHP) unit produces electrical and thermal energy required by the city and by the energy system itself. CO 2 produced by CHP is captured via MEA absorption and converted to methanol via synthesis with hydrogen while also producing carbon black. We consider different carbon reduction scenarios, urbanization levels, system operation conditions, operational costs, capital costs, and energy and material prices in evaluating the system. If such systems are deployed worldwide, subject to produced methanol being equal to the current demand (111 Million ton/yr), they would eliminate 44 Million t/yr CO 2 emissions from existing methanol plants and 160 Millon t/yr CO 2 emissions from standalone energy systems that provide heating and cooling for 40 Million people. • Novel zero–CO 2 –emission energy system meets cities' thermal and electrical needs. • Light industries, housing, public facilities, and sustainable energy are integrated. • Elimination of 60 % and 100 % of current CO 2 emissions. • CO 2 tax, urbanization levels, operation conditions, and prices impact on system design. • Current technology path: CCHP, Methane pyrolysis, CO 2 MEA Capture, MeOH synthesis. [ABSTRACT FROM AUTHOR]

Methanol is receiving considerable attention as an alternative fuel because of its potential role as a transitional option in mitigating greenhouse gas emissions and enabling the transition towards biofuels. Recycled methanol, produced using captured CO 2 or industrial by-product gases, emerges as an attractive alternative in South Korea, especially considering the excessive emissions from its energy and industrial sectors. However, assessing technological superiority amongst a range of alternatives remains challenging. This study aims to assess and compare various methanol production pathways utilizing captured CO 2 and by-product gases from steel industry within context of South Korea. The selected technologies are either currently in industrial use or pivotal for future industrial applications. A unified process design and assessment framework was employed to model and simulate eight technological conversion processes. These processes underwent evaluation based on key performance indicators, accompanied by comprehensive techno-economic and environmental life cycle assessments. Additionally, comparisons were made with conventional fossil-based methanol production, considering different hydrogen and electricity production routes. This study provides valuable insights into the viability of recycled methanol pathways in terms of process performance, economic and environmental feasibility and will facilitate the practical implementation of recycled methanol, contributing towards achieving carbon neutrality objectives. • Eight methanol production routes using waste carbon sources in South Korea are evaluated. • A unified process design framework is employed to model and simulate the processes. • Techno-economic and life cycle assessments uncover the optimal methanol production routes. • Various hydrogen and electricity pathways are considered to propose utilization strategies. • Hydrogen stands out the most crucial element in recycled methanol production. [ABSTRACT FROM AUTHOR]

A novel and efficient multigeneration system aiming to achieve near-zero CO 2 emissions is proposed. The system employs a methanol production process utilizing captured CO 2 from the flue gas of a biomass-gasification plant. The proposed system successfully generates green H 2 through water electrolysis, supported by thermal power, with a portion of the hydrogen reacting with CO 2 to produce e-methanol. Additionally, the system produces other valuable products, including power, cooling, O 2 , and CO 2 , in a coherent manner, benefiting from a low-emission framework and exhibiting high thermodynamic performance. The proposed multigeneration system consists of a biomass-gasification-based power plant, a water electrolyzer, a methanol generation unit, a carbon capture unit, and a steam jet ejector-based refrigeration cycle. The integrated multigeneration system is analyzed from the energy, exergy, and economic aspects. The results demonstrate the system's ability to achieve production rates of 430.25 kg/h of e-methanol and 190 kg/h of green H 2. Furthermore, the energy and exergy efficiencies of the system are found to be 78.13% and 71.63%, respectively. The CO 2 emissions analysis reveals that the proposed system significantly reduced total CO 2 emission to 78.5% (0.61 kg CO2 /kg). The total cost of production is estimated to be 0.087 $/kg. [Display omitted] • Novel integrated biomass-based multigeneration system for power, methanol, H 2 , O 2 , and Cooling. • Captured CO 2 is utilized to produce synthetic e-methanol. • Flue gas from gasification mixed with H 2 from electrolyzer for methanol synthesis. • Obtained the total energy and exergy efficiencies of 78.1 % and 71.6 %, respectively. • Total methanol production and total production cost to be 430.25 kg/h and 0.108$/kg. [ABSTRACT FROM AUTHOR]

This paper presents a novel process for methanol production from blast furnace gas (BFG) and landfill gas (LFG). The process is evaluated using the energy, exergy, economic, and environmental (4E) analyses. The process consists of a power plant fueled by LFG, carbon dioxide (CO 2) chemisorption using 30% (wt.) solution of monoethanolamine, methanol synthesis and separation, and power and steam plants. Thermodynamic analysis shows that the total energy and exergy efficiencies for the proposed process are 59% and 63.2%, respectively. The carbon efficiency for this method is 42%. Environmental analysis shows that the total CO 2 emission is 2614.85 kg/h. Based on the simulation results, this process produces 18,200 kg/h methanol, which results in a CO 2 emission intensity of 0.144 kg CO 2 /kg MeOH. Economic evaluation determines that the proposed scheme has a capital cost of $100, 315, 128.9 with a payback period of 1.94 years. In addition, methanol production's annual profit is $4,798,088.309, and the minimum selling price of the produced methanol is $0.388/kg. The proposed process is a promising alternative for methanol production from BFG and LFG. It has high energy and exergy efficiencies, low CO 2 emission intensity, and a short payback period. The economic analysis shows that the process is profitable. • A novel methanol production system using blast furnace gas and landfill gas is proposed • The system is analyzed from energy, exergy, economic, and environmental viewpoints • The total energy and exergy efficiencies are obtained to be 59% and 63.2%, respectively • This plant produces 18,200 kg/h methanol, which results in CO 2 emission intensity of 0.144 k g C O 2 / k g M e O H . • The proposed plant has a capital cost of 100315128.9 USD with a payback period of 1.94 years. [ABSTRACT FROM AUTHOR]

The present study reports the modeling and simulation of methanol production through the gasification of freshly mined three coal samples having different wt.% of ash, viz., low-ash coal (LAC), medium-ash coal (MAC), and high-ash coal (HAC), collected from three different locations in India. The effect of the input parameters such as steam-to-coal mass ratio and gasification temperature on process performance parameters such as stoichiometric number, syngas yield, green house gas emissions from the process stream or net stream carbon dioxide equivalent, and methanol yield was studied through process sensitivity analysis and input parameters are optimized for the maximum methanol yield and minimum green house gas emission. Primary economic investigation at optimized conditions revealed that an internal rate of return of 5.93% is achieved for HAC at minimum plant scale and setting the methanol selling price of 400 USD/ton whereas IRR obtained as 3.20% and 5.87% for LAC and MAC, respectively, at this condition. The coal sample, HAC, performed better due to a high internal rate of return (i.e., 7.53% at base case) and subsequently low production cost. The present study's findings can be decisive for the countries with substantial low-grade high-ash coal reserves concerning coal diversification for its sustainable consumption in methanol production. [Display omitted] • Equilibrium thermodynamic modelling of steam-coal gasification process. • Kinetic modelling of methanol synthesis process utilizing low-rank Indian coal. • Sensitivity analysis to study the influence of operating parameters. • Detailed comparative techno-economic analysis for methanol production. • Environmental analysis for coal to methanol production. [ABSTRACT FROM AUTHOR]

This paper presents a novel process for the simultaneous production of methanol, oxygen, and electricity through oxyfuel-combustion of landfill gas (LFG) produced from the agricultural residues and proton exchange membrane (PEM) electrolyzer. Among the most important advantages of the proposed process, one can mention high thermodynamic efficiency and negative CO 2 emission. The proposed process includes a PEM electrolyzer, oxyfuel combustion power plant (OFCPP), and methanol synthesis unit (MSU). According to the analyses, this process has energy and exergy efficiency of 75.58% and 86.1%, respectively. In addition, based on the conducted analyses, the total exergy destruction of the process equals 54.21 MW, in which the OFCPP unit with a 76% share has the highest exergy destruction and lowest exergy efficiency. In addition, it is demonstrated that the proposed process converts liquefied natural gas to natural gas. Using oxygen for LFG combustion reduces energy consumption in gas compressors and raises energy efficiency. According to the environmental analysis, it is deduced that the CO 2 emission of this process is negative and equals −0.97 k g C O 2 / k g M e O H , to which the contribution of indirect emission is zero. In addition, economic analysis illustrated that the total annual cost of the process and total methanol cost are 21.6 M$ and 0.62 $/ k g M e O H respectively. • A novel process for methanol, oxygen, and electricity production is devised. • The proposed process includes a PEM electrolyzer, oxy-fuel combustion power plant, and methanol synthesis unit. • This process has energy and exergy efficiency of 75.58% and 86.1%. • CO 2 emission of this process is negative and equals −0.97 k g C O 2 / k g M e O H . • The total annual cost of the process and total methanol cost are 21579497 USD and 0.62 U S D / k g M e O H , respectively. [ABSTRACT FROM AUTHOR]

The methanol and electricity poly-generation system based on coal partial gasification is proposed. Techno-economic analysis of the system is conducted by using Aspen Plus and the effects of methanol synthesis temperature and cyclic gas reflux ratio on the system performance are studied. The detailed economic data are obtained. The IGCC system is established simultaneously and compared with the poly-generation system. The results show that both methanol production and system efficiency decrease with the increase of methanol synthesis temperature. Methanol production increases while system efficiency decreases with increase of the recycle gas ratio. System efficiency would reach as high as 56.8%, while the system efficiency of IGCC is 53.11%. By the calculation of the economic data, the IRR and the payback period of the poly-generation system are 24.1% and 4.14 years, respectively. While IRR and payback period of IGCC system are 3.4% and 18.06 years, respectively. The results show that methanol and electricity poly-generation system based on coal partial gasification has a promising prospect. • The proposed system is based on coal partial gasification and CFB technology. • The power generation efficiency of the PGCC is more than 3% higher than that of IGCC. • The IRR and payback period of PGCC is ∼21% higher and 14 years shorter than that of IGCC. [ABSTRACT FROM AUTHOR]

Methanol is one of the most important chemicals serving as a base for a range of synthetic fuels and variety of other chemical derivates. Steam reforming and autothermal reforming of natural gas represent the major technologies used for syngas production in indirect low pressure methanol synthesis routes. Further process development is driven by technical and economic aspects, while environmental aspects often fade into the background. In this paper methanol production processes using steam reforming and autothermal reforming are investigated from the viewpoint of an exergoenvironmental analysis. The processes feature a coproduction of electricity for high efficiency. The pollutant formation within the chemical conversion units, particularly within the reformer and the furnace, reduces the environmental impact associated with the overall system. The environmental impact of generated methanol and electricity is calculated respectively as 156.4 mPt/kg and 98.2 mPt/MWh for the steam methane reforming process and has values of 134.0 mPt/kg and 71.3 mPt/MWh for the autothermal reforming process. [ABSTRACT FROM AUTHOR]

The current investigation proposes a novel and efficient co-generation with a methanol production process through a power plant flue gas's captured CO 2 in which an alkaline reactor supplies the methanol reactor's input hydrogen. Besides, the compressors, methanol distillation tower, and methanol reactor wasted heat are used as an Organic Rankine Cycle input energy to design a multi-layer wasted heat recovery system. The energy, exergy, economic and environmental approaches are used to assess the plant performance via an Aspen HYSYS code. Accordingly, the total energy and exergy efficiencies are obtained at about 64.13 % and 76 %. The CO 2 capture and methanol separation unit efficiencies are estimated at 42 % and 80 %. Regarding exergy analysis, the methanol reactor has the highest exergy destruction of about 11302.61 k W. The environmental assessment reveals that the total CO 2 emission equals 0.9 t o n C O 2 / t o n M e O H and the Organic Rankine Cycle utilization restricts the indirect emission to the reboilers and distillation columns. Eventually, the total annual cost and total production cost of the proposed scheme are calculated as about 5,638,060 d o l l a r s and 0.73 $ / k g M e O H , respectively. • Proposal of a novel process for power and methanol co-generation by plant flue gas. • Evaluation of the system from energy, exergy, economic, and environmental viewpoints. • Obtaining the total energy and exergy efficiencies of 64.13% and 76%, respectively. • Obtaining total CO 2 emission for the proposed scheme of 0.9 t o n C O 2 / t o n M e O H . • Calculating total annual cost and total production cost of $5638060 and 0.73 $ / k g M e O H . [ABSTRACT FROM AUTHOR]

Recently, steelmaking off-gases generated in the steel industry have been utilized for onsite energy generation. However, these gases have low calorific values that raise their recovery costs and limit their use in refining and separation technology. In contrast, if the large amounts of carbon dioxide, hydrogen, and methane in off-gases can be recovered through refining, high value-added products such as chemical products and renewable fuels can be produced while reducing greenhouse gases. In this study, a large-scale process was designed to produce methanol (MeOH) from coke oven gas (COG), which has a higher calorific value than many steelmaking off-gases, and Linz–Donawitz gas (LDG) as a supplementary carbon source. The COG-only strategy (strategy 1) and the COG + LDG strategy (strategy 2) quantified and compared environmental impacts with coal-based energy generation. The MeOH production process was designed to maximize production of MeOH by considering reaction kinetics, and optimal ratio of COG and LDG in the strategy 2 was also analyzed. The environmental feasibility of the proposed strategies is evaluated in a life cycle assessment (LCA) defined by a "cradle-to-gate" system boundary. Strategy 2 showed mostly improved results (13–62%) compared to strategy 1 in terms of environmental impact along with electricity production. This result shows that utilization of CO in LDG as a carbon source could improve environmental feasibility of off-gas utilization. The sensitivity analysis showed that the energy source has large impact on the environmental feasibility for all impact categories, and the impact is maximized in the energy intensive process. • Methanol production strategy that effectively utilizes steel off-gas was proposed. • Kinetic model was introduced to consider the effect of different off-gas blends. • Environmental impacts were quantified, and its major contributors were analyzed. • Impact of electricity sources, one of the major contributors, the was analyzed. [ABSTRACT FROM AUTHOR]

Both e-methanol and hybrid methanol production can balance the energy systems storing variable wind and solar power and reduce emissions by replacing fossil methanol production. It is expected that hybrid methanol production using additional hydrogen from water electrolysis supplemented with purified product gas from biomass gasification will increase methanol yield and result in lower production costs compared to e-methanol, particularly when using power sources that are not only available all the time during the year. In this article hybrid methanol production with varying hydrogen input from the water electrolysis, e-methanol and biomass gasification-based methanol are evaluated from a techno-economic point of view as a function of key variables. Material and energy balances are estimated using a simulation model in IPSEpro. A key finding is the effect of the hydrogen input on the efficiency and cost of the hybrid process. Converting CO 2 will increase product yield by 101% and only CO by 38.1% compared to biomass-to-methanol production. Additionally, the results show better economics for hybrid methanol production compared to e-methanol >10–12 €/MWh electricity prices at 100 kt methanol production scale and <30–35 €/MWh electricity prices better economics than biomass to methanol with a biomass input of 70 MW. • The hybrid process studied utilised only CO or both CO and CO2. • Compared to biomass to methanol case the methanol yield increased 38–101%. • Compared to biomass to methanol case the carbon yield increased from 38.1% to 89.9%. • The production could use a flexible amount of electricity balancing energy systems. • A production cost of 460 €/ton was estimated for 100 kt annual methanol production. [ABSTRACT FROM AUTHOR]

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]

Abstract Carbon capture and utilization represents a major strategy to reduce anthropogenic CO 2 -emissions by valorization to chemical and petrochemical products. The integration of CO 2 is not only aimed at abating emissions, but also at a partial substitution of raw materials, most of which are fossil fuels. In this context, Gas-to-Liquid processes are of great importance, in particular the production of methanol from its predominating feedstock natural gas. In the present study the CO 2 -utilization potential and impact of CO 2 -integration measures in methanol synthesis routes are investigated and assessed from a thermodynamic point of view. Sensitivity analyses for an estimation of the CO 2 -integration potential by dry reforming and direct hydrogenation are carried out. In a dry-reforming process, a carbon dioxide-to-methane mole ratio of one results from tradeoffs among the CH 4 -conversion, the desired syngas composition, and the heat demand. Regarding the direct hydrogenation, a CO 2 inlet fraction of 10 mol-% is recommended for a pareto-optimal operation with a high product yield and a large conversion rate for CO 2. The CO 2 -integration measures are implemented into three processes to evaluate and assess their effects on the overall systems by means of an exergetic analysis. The processes mainly differ in regard to the reforming technology and use conventional steam reforming, dry reforming by CO 2 , and mixed reforming. Compared to a conventional production process, the natural gas feed is successfully decreased by 38.7 t/h, 50.3 t/h and 61.4 t/h, while an amount of 191.5 kg CO2, 89.3 kg CO2, 425.8 kg CO2 per MWh total exergy of product can be abated, respectively. The process with mixed reforming exhibits a large exergetic efficiency of 48.6%, resulting from a careful integration of CO 2 in conjunction with further syngas conditioning units. The processes with steam reforming and dry reforming have, however, lower efficiencies (31.1% and 39.8%, respectively) due to large irreversibilities within the furnace and the steam cycle, which result from the required large amounts for high-temperature process heat. The analyses show that the CO 2 stream must be integrated carefully to the plant in order to avoid an excessive increase of the irreversibilities. Highlights • The impacts of CO 2 -utilization measures in the production of methanol are assessed from an exergetic point of view. • The limitations of CO 2 -integration by dry reforming and hydrogenation are investigated by parametric analyses. • The implementation of these measures results in a large feedstock reduction and CO 2 -abatement. [ABSTRACT FROM AUTHOR]

Global warming caused by the accumulation of atmospheric CO 2 has received widespread attention in recent years. The direct CO 2 integration process in NG-based methanol (MeOH) synthesis plant is one of the predominant CO 2 utilization technologies. However, a large amount of water produced in the MeOH reactor increasing the difficulty in the subsequent purification system and the high direct CO 2 emissions are caused by the low CO 2 conversion rate. In view of such issues, we propose an innovative MeOH production approach based on a parallel-series system combining steam methane reforming (SMR) and dry methane reforming (DMR) to achieve a high-efficiency utilization of CO 2 . In this approach, the CO 2 from SMR and that from additional feeding are converted into CO with a proper amount in the DMR reformer, and thus the content of CO 2 in the make-up gas becomes more appropriate than that of existing processes, and the conversion rate of CO 2 to MeOH could be obviously increased, what is more, the corresponding direct emissions of CO 2 could be significantly reduced. On the other hand, the carbon efficiency is introduced to evaluate the conversion efficiency of all raw material ( i.e. , CH 4 and CO 2 ) containing the carbon atoms. The comparative evaluations are carried out using Aspen Plus V8.4 ® and the proposed improved process is demonstrated to be more efficient than existing ones from views of technological, economic, and environmental metrics. [ABSTRACT FROM AUTHOR]

In a petrochemical complex in Iran, for production of 209575 kg of MeOH/h, 154,712 kg/h of flue gas with a CO 2 concentration of 10.74 mol% enter the atmosphere through a fired heater. The target of this study is to investigate the effect of using post-combustion CO 2 capture technology to reduce carbon dioxide emissions and use it to increase methanol production. In order to, the proposed process was simulated and effect of three different solvents, including piperazine (PZ) 30 wt%, monoethanolamine (MEA) 30 wt%, and a blend of MEA 20 wt %+ PZ 10 wt % were investigated. This study investigated solvent regeneration energy, CO 2 absorption rate, energy efficiency, and exergy efficiency of stripper column. Simulation results showed PZ with 93% energy efficiency, 55.45% exergy efficiency of stripper column, CO 2 emission intensity equal to 0.01 t CO2 /t MeOH and lowest solvent regeneration energy equal to 2.6 GJ reb /t CO2 has better performance than the other two solvents. Also, the simulation results showed that blending CO 2 output from PZ solvent with syngas increases methanol production by 7.8%. The techno-economic analysis also indicated proposed process is more profitable than original process. [Display omitted] • Post-combustion CO 2 capture process was used to reduce carbon dioxide emissions. • Methanol production increased 7.8% by blending CO 2 from PZ solvent with syngas. • The effect of PZ, MEA, and blend of them on CO2 capture was investigated. • The energy efficiency and stripper column exergy efficiency of piperazine solvent are 93% and 55.45%, respectively. • The MEA solvent with 94.25% absorption and CO 2 emission intensity 0.0086 t CO2 /t MeOH was superior to two other solvents. [ABSTRACT FROM AUTHOR]

The decomposition of hydrocarbons or alcohols by non-thermal plasma discharge has potential for rapid hydrogen production. Hydrogen production using liquid raw materials is more secure and economical for transportation. In this study, liquid plasma discharge was used to induce methanol decomposition and analyzed factors affecting the decomposition reaction as well as the evolution of the plasma bubble. A liquid plasma discharge reactor was designed for visualization. Liquid-phase discharge and methanol decomposition processes were imaged in detail using a high-speed camera. At the plasma-liquid interface of a bubble substrate, energy is concentrated and methanol is decomposed into gaseous products. The bubbles detach from the tip of the plasma bubble substrate and the decomposition reaction is continuous and stable. Two typical plasma discharge modes were obtained by adjusting the electrode spacing: gliding arc discharge (GAD) and glow discharge (GD). The voltage and current curves of GD approximate the sinusoidal waveform of the alternation current power supply, and the range of discharge power is 130.4–460.2 W. However, GAD has feature of the bipolar pulses with a high transient peak current (420.6–690.9 mA) that causes discharge power of GAD excitation is 30.7–110.3 W. Primary analyzes indicate that the energy consumption of GAD is less than that of the GD due to the difference in discharge characteristics. An optimized energy consumption of 1.63 kWh/Nm3H 2 was achieved for hydrogen production. The maximum hydrogen proportion of the gaseous product is 63.21%, which corresponds to a carbon monoxide proportion of 26.38% as the main byproduct. The effects of the discharge power, electrode distance, and electrode diameter on methanol decomposition were analyzed. • A novel liquid-phase plasma discharge reactor was designed for hydrogen production. • Liquid methanol decomposes at the plasma–liquid interface by non-thermal plasma. • Increasing the electrode diameter leads to a decrease in the electric field strength. • The electrode spacing has a direct effect on the plasma mode. • GAD is more suitable for constructing on-board hydrogen production systems than GD. [ABSTRACT FROM AUTHOR]

This paper proposes a novel power and methanol cogeneration due to biogas upgrading, liquefied natural gas cooling, and natural gas combined reforming. The proposed process consists of biogas upgrading, combined natural gas reforming and synthase, power plant, and methanol separation. The designed scheme performance is analyzed from energy, exergy, economic, and environmental assessments carried out by Aspen HYSIS software. The exergetic investigation revealed that the overall exergy destruction is about 14971.9 kW, in which the combined power cycle has the main portion of 39.11%. The results reveal the methanol and power generations capacity of 0.723 k W / k W M e O H and 16.68 k W / k W e l , respectively. In this regard, the combustion chamber with 15.43% and the vapor generator with 14.65% share in total exergy destruction, have the main contribution to exergy destruction. Moreover, the total energy and exergetic efficiencies are calculated 77.6% and 91.3%. Also, the methanol and power production cost rates are obtained 0.23 U S D / k g and 0.041 U S D / k W h. Finally, the environmental analysis shows that the system's CO 2 footprint is 0.039 k g C O 2 / M J. • An integrated process for natural gas, electricity, and methanol production is presented. • The proposed process is simulated from energy, exergy, environmental and economic viewpoints. • Thermodynamic analysis indicated that total energy and exergy efficiencies are 77.6% and 91.3%. • The economic study showed that the methanol total product cost is 0.23 U S D / k g. • The environmental analysis revealed a CO 2 footprint of 0.039 k g C O 2 / M J. [ABSTRACT FROM AUTHOR]

In this study, biological methanol production under repeated batch conditions by immobilized Methylocystis bryophila , using simulated biogas of methane (CH 4 ) and carbon dioxide (CO 2 ) as a feed is demonstrated for the first time. The composition of the simulated gas mixtures significantly influenced methanol production by M. bryophila, and in all cases, higher concentrations were achieved than with pure CH 4 alone. Under optimum conditions, maximum methanol concentrations of 4.88 mmol L −1 , 7.47 mmol L −1 , and 7.02 mmol L −1 were achieved using the gas mixtures CH 4 :CO 2 (2:1 ratio), CH 4 :hydrogen [H 2 , (4:1 ratio)], and CH 4 :CO 2 :H 2 (6:3:2 ratio), respectively, as feed, with a fixed CH 4 concentration of 30%. Methanol yield was increased to 7.85 mmol L −1 using covalently immobilized cells and the simulated gas mixture CH 4 :CO 2 :H 2 (6:3:2 ratio). Under repeated batch conditions, immobilized cells produced a significantly higher cumulative methanol concentration (25.75 mmol L −1 ) than free cells (15.50 mmol L −1 ), using a simulated biogas mixture of CH 4 :CO 2 (2:1) and eight reuse cycles, suggesting that this mixture can potentially be utilized as a feed for the production of methanol. Furthermore, the effective utilization of low-cost feedstock, derived from natural sources, containing gas mixtures of CH 4 :CO 2 , CH 4 :H 2 , or CH 4 :CO 2 :H 2 , constitute an economical and environmentally friendly approach to the reduction of greenhouse gases. [ABSTRACT FROM AUTHOR]

Energy and exergy analyses were carried out for a medium-capacity methanol plant based on a low-pressure synthesis process for natural gas. The process comprises a pretreatment of natural gas, a steam-methane reforming unit for generation of synthesis gas, a methanol synthesis, a distillation of crude methanol, and an integrated steam cycle for waste heat recovery. Carbon dioxide from carbon capture is used for gas conditioning by adjusting the syngas module for methanol synthesis through counterbalancing of the excess hydrogen. A sensitivity analysis was performed to identify favorable operation parameters for the tubular steam reformer. The energetic and exergetic efficiencies for the overall system were found to be 35.9% and 37.7%, respectively. The specific energy requirements (energy intensities) are 19.6 GJ th /t CH3OH and 0.8 GJ el /t CH3OH , while the specific methane consumption was calculated to be 0.54 ton CH 4 per ton CH 3 OH. Compared to a stand-alone plant, the utilization of carbon dioxide increases the methanol yield by 22%. The exergy analysis shows that the highest inefficiencies occur in the reforming unit, the steam cycle, and the synthesis unit. In particular, the steam reformer, the synthesis reactor, and several heat exchangers show a high potential for thermodynamic improvement. [ABSTRACT FROM AUTHOR]

The coke-oven-gas-to-methanol (CGTM) process is one of the most important coal-to-chemical processes. However, it suffers from ineffective hydrogen utilization, limiting both its capacity and energy efficiency. In addition, currently, there is a large amount of low-quality pulverized coke that cannot be used for value-added applications. In this paper, two pulverized coke-assisted CGTM processes (PC-CGTM1&2) are proposed. In these processes, coke-oven gas is either partially oxidized or steam reformed to generate a hydrogen-rich syngas, and simultaneously gas produced by the gasification of pulverized coke is used to adjust the ratio of hydrogen and carbon to about 2, ideal for methanol synthesis. The results show that the optimized mass ratios of PC/COG are 0.27 and 0.51 for the PC-CGTM1&2, respectively. Their exergy efficiencies are increased to 71.3% and 75.9% from 58.6% in the CGTM process. Their methanol productivities are also increased to 0.63 and 0.75 from 0.43 Mt/y. The total product costs of the PC-CGTM1&2 are 21 and 43 US$/t lower than that of the CGTM (282 US$/t). The internal rates of return for these new processes are 19.7% and 25.7%, whereas it is only 13.5% for the CGTM, demonstrating the ability of the new processes to resist inflation and market risk. [ABSTRACT FROM AUTHOR]

The present study evaluates a sugarcane biorefinery producing ethanol through juice fermentation and methanol via gasification of sugarcane lignocellulosic residues and liquid fuel synthesis. Two technologies of gasification named entrained flow and circulating fluidized bed are compared. Flowsheet modeling and thermo-economic analysis methods are applied, followed by a multi-objective optimization based on a genetic algorithm. The optimum Ethanol–Methanol biorefinery design options are compared with other previously studied sugarcane biorefineries. The results show that the biorefinery's energy efficiency increases significantly with the integration of a methanol production plant in a conventional ethanol distillery. The configuration using an entrained flow gasifier presents lower conversion efficiency than the one using a circulating fluidized bed gasifier. However, for the entrained flow gasifier configuration, the size of the methanol production process could be bigger since more heat is available for the ethanol process favouring the integration with the ethanol plant. Higher energy efficiency due to increase of methanol production leads to a higher total investment for both gasification technologies. The cost analysis shows that the calculated methanol production cost is 30% higher than its current market price. Environmental incentives for biofuels could change this scenario but are not in the scope of this study. [ABSTRACT FROM AUTHOR]

Methanol is an important chemical product with wide application. Due to the high pollutant emission of coal-to-methanol route, feeding mixed raw material of biomass and coal is seen as a promising measure of improvement. More than just focusing on co-gasification unit, this study performs a full process simulation from co-gasification to methanol and cogeneration, aiming at revealing the impact of biomass on process operation and optimizing the key operating parameters. The simulation results imply that coal and biomass co-gasification can improve the utilization of raw materials with more effective gas produced. As an example, the process based on the co-gasification of bituminous coal and straw is specially studied and telling the best operating situation of the whole process. The gasification agent and the critical effects of crude syngas split ratio (SR) and unreacted gas recycle ratio (CR) on the net methanol yield are fully discussed to gain insight into the process. The simulation results show that when the ratio of biomass to coal is 1:1, gasification agent is water steam, SR = 0.36, CR = 0.8, the net methanol production can reach a maximum of 7022.32 kg/h, 241.51% higher than that of merely using coal, producing 37.68% less CO 2 than merely using coal. • Full simulation of biomass and coal to methanol and cogeneration is performed. • Effects of factors on syngas components and net methanol yield are analyzed. • Side reactions are considered in methanol synthesis process. • Combined heat and power process is integrated with production process. • CO 2 emission reduces by 37.68% in co-gasification to methanol. [ABSTRACT FROM AUTHOR]

In this paper, a methanol production process with high thermodynamic efficiency and a low production cost is presented. The proposed process is based on steam methane reforming, in which carbon dioxide (CO 2) captured from a power plant flue gas is employed to improve the stoichiometric number, methanol efficiency, and carbon efficiency and increase CO 2 conversion. In addition to the sensitivity analysis, comprehensive technical, economic, and environmental analyses are performed. Furthermore, the obtained results of this paper are compared to those of previous studies. A parametric study showed that the optimum steam-to-methane ratio is 3.75, and the optimum flow rate for CO 2 utilization is 140 kmol/h. From the economic point of view, it is demonstrated that the total annual cost is 11,799,484 USD, and the total production cost rate is 0.1 $/kg. The environmental analysis showed that the total net CO 2 emission in this process is 6580.64 kg/h, and for producing 1 kg of methanol, 0.41 kg of CO 2 is emitted. • Proposal of a methanol production cycle based on steam-methane reforming. • Improving stoichiometric number, methanol efficiency, carbon efficiency, and CO 2 conversion using the proposed system. • According to the results, the optimum value of the steam to methane is obtained 3.75. • The total annual cost and production cost rate are estimated 1,179,948 $ and 0.1 $/kg. [ABSTRACT FROM AUTHOR]

Transportation sector, particularly road transport, together with the industrial expansion stand out as key factors behind the unprecedented CO 2 levels, hence the need for green fuel alternatives and sustainable technologies. The present investigation evaluates methanol (MeOH) production via direct CO 2 hydrogenation, and conversion into valuable derivatives: i) formalin, ii) dimethyl ether (DME), iii) methyl tert -butyl ether (MTBE), and iv) biodiesel through modelling and simulation, as well as environmental assessment. Hydrogen is produced by water electrolysis considering three different energy scenarios: i) EU grid mix; ii) wind power; iii) hydro power. The amount of CO 2 needed is obtained from cement manufacturing through a chemical scrubbing process using Methyl-Di-Ethanol-Amine (MDEA). The environmental analysis is carried out following the Life Cycle Assessment (LCA) methodology using GaBi software, and ReCiPe as impact assessment method. The key performance indexes, main product purity (>99%) and energy requirements (i.e., 1.72 MW e /t, and 5.89 MW e /t respectively) point towards alkali biodiesel, and MTBE production as the most promising MeOH conversion routes. The environmental analysis highlights that MeOH production and conversion towards alkali biodiesel process displays the lowest impact score for each energy scenario. The second-best conversion route is MTBE when using the grid mix energy scenario, and formalin when wind or hydro power is considered. [ABSTRACT FROM AUTHOR]

This study is for the technoeconomic analysis of an integral facility consisting of wind energy-based electrolytic hydrogen production, bioethanol-based carbon dioxide capture and compression, and direct methanol synthesis. ASPEN Plus was used to simulate the facility producing 97.01 mt (metric tons) methanol/day using 138.37 mt CO 2 /day and 18.56 mt H 2 /day. A discounted cash flow diagram for the integral facility is used for the economic analysis at various hydrogen production costs and methanol selling prices. The feasibility analysis is based on a multi-criteria decision matrix consisting of economic and sustainability indicators comparing renewable and non-renewable methanol productions. The overall energy efficiency for the renewable methanol is around 58%. Fixation of carbon reduces the CO 2 equivalent emission by around −1.05 CO 2 e/kg methanol. The electrolytic hydrogen production cost is the largest contributor to the economics of the integral facility. The feasibility analysis based on multi-criteria shows that renewable methanol production may be feasible. [ABSTRACT FROM AUTHOR]

As a main growing greenhouse gas emitter, petroleum refining is responsible for 4%–10% of the global carbon dioxide (CO 2) emissions, of which approximately 25% is derived from fluid catalytic cracking (FCC) units. The flue gas released by FCC units has a high CO 2 content (11–17 vol%), creating potential for methanol production when the methane and hydrogen in the dry gas as a byproduct of FCC are considered. To unlock this low-carbon opportunity for refineries, we employed Aspen Plus to develop a methanol synthesis system by recovering the CO 2 in the flue gas and the methane and hydrogen in the dry gas of an FCC unit. Based on pinch theory, a process heat integration technique was designed and optimized to reduce the energy penalty of the system. The developed system enables an annual CO 2 mitigation of 2.80 million tons and boosts the energy efficiency of the FCC units by 2.8%. The system developed by this study is more economically favorable than traditional coal-to-methanol production. The developed system provides technological routes for refineries to achieve large-scale CO 2 mitigation, thus advancing the green transition of the petrochemical industry. • A CO 2 –dry gas to methanol (CTM) system for low-carbon refinery was developed. • The CTM system enables high value-added application of dry gas. • The CTM system increases the energy efficiency of the fluid catalytic cracking by 2.8%. • The annual CO 2 mitigation of the CTM system is 1.93 t CO 2 /t methanol. • The economic payback time of the CTM system is about 4 years. [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]

In the present study, a methanol synthesis plant integrated with a hydropower station with river hydro storage option is developed and analyzed thermodynamically to study the ability of increased benefit and sustainability via the generation of multiple useful commodities. The present system is, in this regard, designed to produce methanol steadily throughout the day at baseload and generate power at an increased rate during the on-peak period. This system also cogenerates heat and fresh water through reverse osmosis and oxygen via water electrolysis. The methanol synthesis unit is simulated in the AspenPlus in a recirculation loop based on a plug flow pressurized reactor. The reaction extent for synthesis reaches a maximum at an optimum temperature for any specified pressure. The water electrolysis is conducted at 80 °C and 2 kA/m2 since the parametric study confirms that at higher current density, the duty of the water preheating heat exchanger becomes high, which increases unnecessarily the capital investment. One key focus of the paper is to devise the operating strategy of hydro-storage, which is done for an illustrative case study in which the hourly Ontario electricity price (HOEP) for the year 2020. The system is controlled in such a way that the power generation during the on-peak periods is maximized for increased revenue. A river with a 425 m3/s annual average flow rate is assumed for the case study. The gross head for hydro-storage must reach a maximum at about 30 m at 7 a.m., and 6 p.m. and the storage pool is discharged to 23 m after morning peak and to 20 m after evening peak. The overall energy efficiency of the system is found to be 61.6%. The overall exergy efficiency of the system is obtained to be 58.2% with a generation mix of grid-delivered power, methanol, heating, oxygen and fresh water. • A new concept of hydropower-based system integrated with methanol synthesis plant. • Multigeneration is achieved with electricity, Methanol, Oxygen and fresh water. • Overall energy efficiency of the developed system is 61.6%. • Exergy efficiency of overall system is 58.2%. [ABSTRACT FROM AUTHOR]

Abstract: This study evaluates the potential for reducing life cycle greenhouse gas (GHG) emissions of biomass gasification-based methanol production systems based on energy balances. Configurations which are process integrated with a chemical cluster have been compared to stand-alone units, i.e. units with no connection to any other industry but with the possibility to district heating connection. Two different uses of methanol are considered: the use as a vehicle fuel and the use for production of olefins via the methanol-to-olefins process. An added value of the integration can be the availability of excess hydrogen. For the studied case, the methanol production could be increased by 10% by using excess hydrogen from the cluster. The results show that the integrated systems have greater potential to reduce GHG emissions than the stand-alone systems. The sensitivity analysis demonstrated that the references for electricity production and district heating production technology have important impacts on the outcomes. Using excess heat for district heating was found to have positive or negative impacts on GHG emissions depending on what heat production technologies it replaces. The investigated olefins production systems resulted in GHG emissions reductions that were similar in magnitude to those of the investigated biofuel production systems. [Copyright &y& Elsevier]

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]

CO 2 -conversion technology provides both CO 2 emission reduction and new value chains and is now becoming a key player in moderating global temperature increase. In this study, CO 2 -methanol synthesis processes are evaluated through life cycle assessment. Four conversion processes are selected to represent different technological readiness level (TRL) groups. Coal gasification and coking conversion process for high TRL while hydrogenation and photocatalytic conversion process represent mid and low TRL. Coal gasification conversion shows the highest global warming potential (GWP) with 17.7 kg CO 2 eq , followed by hydrogenation conversion, and coal coking conversion. Photocatalytic conversion showed the lowest GWP with 2.28 kg CO 2 eq. The mid-to-low TRL conversion processes are analyzed by varying heat and electric sources. Through variation, feasibility of reducing CO 2 emission to low-TRL level is confirmed. Although emission reduction sensitives upon energy sources are varied, hydrogenation conversion process reduced the GWP from 10.7 to 1.65 kg CO 2 eq. Through the study, it is verified that hydrogenation conversion could be a bridge to green methanol until technological development of photocatalytic conversion, an acceleration to zero-emission. • CO 2 -methanol synthesis processes evaluated through life cycle assessment. • Power generation data of Rep. Korea integrated to evaluate environmental impact. • Feasibility of reducing CO 2 emission of mid- and low-TRL conversion evaluated. • Optimization of energy sources to reduce CO 2 emission of mid-TRL conversion verified. [ABSTRACT FROM AUTHOR]

This article presents a thermodynamic analysis of a system for producing "renewable" methanol from H 2 generated from electrolysis, fed by surplus energy from a 40 MW wind farm WF during the night valleys and from CO 2 captured from a power plant's flue gas. A methodology determining the energy efficiency of the entire methanol production and purification installation was developed, as well as a methodology for determining the efficiency of its components, i.e. the hydrogen generator HG (η H G ) and the methanol generator MG (η M G ). A number of effective ways to improve these efficiencies were proposed and analyzed. To evaluate the cooperation of the HG with a WF, a number of indicators were introduced: an indicator of the maximum working time utilization, a rated power index for the generator, an energy storage indicator, and an indicator for the working time with nominal power. The listed efficiency and indices were determined as a function of the nominal power of the HG in relation to the nominal power of the WF (in a range from 1 to 45%). The energy efficiency of the entire system under study, η , ranged from 45.5% to 52.9% with a MG efficiency of 69%–69.64%. The use of heat from compressed gases increased the efficiency η by 0.98 p. p. Relative to the best variant, while the use of compressed gas heat, waste heat from the methanol production and purification installations, and the use of the chemical energy of residual gases gave a possibility of achieving an efficiency exceeding 60% (60.4%). • Integration of wind farm, electrolysis process and methanol production was presented. • Energy storage in the form of methanol in a wide range of use of wind energy. • The energy efficiency of the entire system ranged from 45.5% to 52.9%. • The use of heat from compressed gases increased the efficiency by 0.98 p. p. [ABSTRACT FROM AUTHOR]

Methanol, a liquid hydrogen carrier, can produce high purity hydrogen when required. This review discusses and compares current mainstream production pathways of hydrogen from methanol. Recent research efforts in methanol steam reforming, partial oxidation, autothermal reforming, and methanol decomposition are addressed. Particular attention is paid to catalyst development and reactor technology. Copper-based catalysts are popular due to their high activity and selectivity towards CO 2 over CO but are easily deactivated and have low stability. Attempts have been made using different metals like zinc, zirconia, ceria, chromium, and other transition metals. Catalysts with spinel structures can significantly improve activity and performance. Palladium-zinc alloy catalysts also have high selectivity towards H 2 and CO 2. For reactors, novel structures such as porous copper fiber sintered-felt are prefabricated and pre-coated before employment in microreactors. Monolith structures provide maximum surface area for catalyst coatings and lower pressure drops. Membrane reactors drive reactions forward to produce more H 2. Swiss-roll reactors achieve heat recovery and energy saving in reactions. In summary, this comprehensive review of hydrogen production from methanol is conducive to the prospective development of a hydrogen-methanol economy. Image 1 • Four main hydrogen production processes from methanol are reviewed. • Reaction mechanisms for methanol thermochemical conversion are discussed. • Recent progress in catalyst and reactor developments is reported. • A qualitative comparison between the processes is addressed. • Perspectives and challenges for hydrogen production from methanol are underlined. [ABSTRACT FROM AUTHOR]

Thermochemical conversion of biomass is a promising option to produce energy-dense liquid biofuels, aiming to phase out fossil fuels from the transportation sector. Integration of renewable electricity boosts biofuel yield and carbon conversion from the scarce biomass resource, creating an indirect electrification of the transportation sector. Coupling biomass gasification and solid oxide cells (SOC), able to run in both electrolysis and fuel cell mode, constitutes the framework for flexible biofuel production. This paper compares the performance of five novel plant configurations for flexible biomass conversion to methanol and power. The plant performance is evaluated at five different operation modes: high production of methanol at low/intermediate electricity prices, co-production of electricity and methanol at high prices, and production of electricity without methanol co-production at price peaks. A TwoStage gasifier, a bubbling fluidized bed and an entrained flow gasifier are chosen as gasification technologies. The systems are thermodynamically modeled, and analyzed in terms of efficiency and carbon conversion. The highest efficiencies are achieved with the systems based on TwoStage Electro-gasifier (71%) and entrained flow gasification with pyrolysis as fuel pre-treatment (72%). The flexibility achieved by this technology combination enables high capacity factors, important for an accelerated commercialization of thermochemical biomass conversion. • Flexible methanol production units able to operate at different electricity prices. • Biomass gasification platforms coupled with solid oxide cells to produce methanol. • Highest input-output efficiency of 72% using entrained flow biomass gasification. • Highest carbon conversion of 97% using entrained flow biomass gasification. [ABSTRACT FROM AUTHOR]

Coke-oven gas and Linz Donawitz gas are pollutive by-product gases generated from steel plants. The gases are currently combusted or released to atmosphere, but those can be economically utilized as chemical product. Thus, this study proposes improved methanol production process from the gases, by considering two different strategies: efficiency (Case 1) and productivity (Case 2). Both processes are rigorously integrated using Aspen Plus V10 and evaluated from the perspectives of productivity, thermodynamic efficiency, environmental impact, and techno-economics. Compared to Case 1, Case 2 had 2.1 times the productivity but required 3 times natural gas. As a result, Case 1 showed better efficiencies of 58–68% (46–56% in Case 2), reduced larger carbon emission of 425 kmol/h (123 kmol/h in Case 2), and had lower minimum selling price of 371 $/tonne (398 $/tonne in Case 2). Two proposed processes are also economically superior than similar previous processes (550–712 $/tonne). This study confirms that both presented novel processes are sustainable and economically viable, and also improves the understanding of methanol production from the waste gases of steel production. • Improved methanol production system from by-product gases is proposed. • Two trade-off strategies are considered and compared in terms of various perspectives. • Proposed processes are sustainable, economically viable, and superior than previous processes. [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]

This paper presents conceptual design, economic evaluation, and sensitivity analysis of a commercial scale carbon-utilization process that produces methanol (MeOH) from blast furnace gas (BFG). Three process cases that use different N 2 compositions in the feed (Case 1: 40%, Case 2: 35%, and Case 3: 30%) are simulated. The kinetic model over a commercial Cu/ZnO/Al 2 O 3 catalyst is used to consider the effect of N 2 on the reaction and to find the optimal process synthesis condition. The proposed process yields 78.3–113.3 kt MeOH /y with 32.2–40.2% energy efficiency, and after heat integration it has no requirement for external heat. Case 3 improves energy efficiency by 5.2% compared to the conventional electricity production process from BFG. The process is assessed using techno-economic and environmental metrics. The lowest minimum selling price of US$ 902/t MeOH and the highest potential to reduce CO 2 emissions of 3.9 t CO2 /t MeOH are obtained for Case 3. Sensitivity analysis for H 2 , electricity price and major economic assumptions shows that Case 3 is the better option in the ranges of H 2 price, except high-priced H 2 produced by solar energy, and in ranges of electricity price using current technology. Case 3 is a techno-economically viable alternative under positive assumptions. • A novel strategy for methanol production from blast furnace gas is proposed. • Large-scale process conceptual design is simulated based on validated kinetic model. • Three process cases with different N 2 compositions in feed are examined. • An economic and climate impact analysis of the process are performed. • Considering carbon credit improves process economics. [ABSTRACT FROM AUTHOR]

Technical and sustainability analyses of the methanol production via the integrated biomass pyrolysis, gasification, and methanol synthesis (IBPGM) process using rice straw as feedstock, are performed. The utilization of emitted CO 2 by recycling to a gasifier as a gasifying agent is investigated for technical and environmental reasons. The effects of CO 2 recirculation on the product distribution and energy consumption of the IBPGM process are examined. The production rate of methanol is improved with the increased CO 2 recycle fraction, while that of bio-oil does not change. The IBPGM is a highly exothermic process, with the largest energy-releasing unit being the methanol reactor. The energy consumption at the gasifier exhibits the same trend and thermal self-sufficiency is consequently achieved when the recycle fraction is raised to 0.76. Environmental assessment using a life cycle analysis tool reveals that the energy management of methanol synthesis unit and syngas processor needs to be improved as they highly contribute toward the carbon footprint and potential environmental impact. The technical and environmental factors of the IBPGM process are evaluated by the analysis hierarchy process, calculated by a multi-criteria decision analysis method. The IBPGM process with the CO 2 recycle fraction of 0.2 offers the best performance. Under this condition, the methanol and bio-oil production rates of 0.23 and 0.09 kmol h−1, respectively, and the energy efficiency of 60.7% can be achieved, based on the biomass feed rate of 1 kmol h−1. • The methanol production from the IBPGM process is performed. • Two configurations, once-through and with CO 2 recirculation concepts, are compared. • Suitable adjustment of CO 2 recycle fraction can maximize methanol yield. • Methanol synthesis reveals the highest carbon footprint. • CO 2 recirculation influences on the PEI of the IBPGM process. [ABSTRACT FROM AUTHOR]

In the current context of global energy transition, the coupling of methanol production with offshore oil & gas operations appears to be a promising option to share infrastructures and convert renewable energy into valuable fuel. However, renewable methanol synthesis has not yet reached the commercial stage. Moreover, there is no evidence on studies integrating offshore multiple resources into methanol process. The novelty of this paper is a performance analysis of emerging routes for methanol production driven by offshore wind-solar energies through exergy and exergoeconomic techniques. Two production schemes (catalytic hydrogenation of carbon dioxide and direct radical oxidation of methane) are properly designed to produce a fixed methanol rate driven by offshore wind farm and solar-thermal plants at a given oil & gas rig. The results demonstrate that carbon dioxide-based route shows the lowest exergy destruction rate (66 MW) and total cost rate (1000 $/h) compared to other option. In conjunction with this, the methane-based route gives a satisfactory exergy efficiency of 87% against a mere 2% of other pathway, as well as higher potential to increase cost savings due to lower exergoeconomic factor. Furthermore, influences of varying some key variables on the proposed parameters of the two options are investigated. • Exergy and exergoeconomic performance of novel CH 3 OH processes are investigated. • Offshore solar-wind energy is integrated into CO 2 hydrogenation and CH 4 oxidation. • Wind-diesel power plants show the worst exergy performance in both schemes. • CH 3 OH synthesis gives the highest share to total costs in CH 4 oxidation option. • Use of oil&gas sources in the process improves exergy efficiency and cost savings. [ABSTRACT FROM AUTHOR]