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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]

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]

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]

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]

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]

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]