Methanol Synthesis Unit Research Articles

Sustainable Biomethanol and Biomethane Production via Anaerobic Digestion, Oxy-Fuel Gas Turbine and Amine Scrubbing CO2 Capture

Energy policies around the world are increasingly highlighting the importance of hydrogen in the evolving energy landscape. In this regard, the use of hydrogen to produce biomethanol not only plays an essential role in the chemical industry but also holds great promise as an alternative fuel for global shipping. This study evaluates a system for generating biomethanol and biomethane based on anaerobic digestion, biogas upgrading, methanol synthesis unit, and high-temperature electrolysis. Thermal integration is implemented to enhance efficiency by linking the oxy-fuel gas turbine unit. The integrated system performance is evaluated through thermodynamic modeling, and Aspen Plus V12.1 is employed for the analysis. Our findings show that the primary power consumers are the Solid Oxide Electrolysis Cell (SOEC) and Methanol Synthesis Unit (MSU), with the SOEC system consuming 824 kW of power and the MSU consuming 129.5 kW of power, corresponding to a production scale of 23.2 kg/h of hydrogen and 269.54 kg/h of biomethanol, respectively. The overall energy efficiency is calculated at 58.09%, considering a production output of 188 kg/h of biomethane and 269 kg/h of biomethanol. The amount of carbon dioxide emitted per biofuel production is equal to 0.017, and the proposed system can be considered a low-carbon emission system. Key findings include significant enhancements in biomethanol capacity and energy efficiency with higher temperatures in the methanol reactor.

Optimizing trigeneration energy systems: Biogas-centric methanol production via direct CO2 hydrogenation with advanced integration of PEM electrolyzer and LNG cold technology

Biogas, a sustainable alternative to fossil fuels, addresses issues of non-renewability and accessibility. Its structural similarity to fossil fuels makes it a potent option for energy systems. With this in mind, this paper discusses a novel trigeneration system that utilizes biogas and Liquefied natural gas cooling to produce methanol, electricity, cold water, hot water, oxygen, and natural gas. The system integrates various components such as a biogas burner, Kalina cycle, organic Rankine cycle, liquefied natural gas liquid gasification cycle, proton exchange membrane electrolyzer, and methanol synthesis unit. Simulation via Aspen HYSYS software includes an analysis of energy, exergy, economic, and environmental aspects. Efficiency assessment in single generation, cogeneration, trigeneration, and chemical trigeneration modes concludes chemical trigeneration as most efficient, with the proton exchange membrane electrolyzer being the most efficient subsystem. Key variables like Kalina cycle evaporator temperature, gas flow rate to the methanol reactor, and organic Rankine cycle working fluid pressure are assessed. Predictions on thermodynamic, environmental, and economic behaviors, along with their fluctuations, are made. Using a thermoeconomic approach, the economic analysis determines an exergy unit cost of 59.79 $/GJ and a total cost rate of 2764 $/h. Overall, this work presents a novel and efficient chemical trigeneration system that utilizes biogas and LNG cooling to produce multiple products.

Multi-aspect assessment of a novel geothermal-driven polygeneration arrangement using water electrolyzer, methanol synthesis unit, and Goswami cycle

Geothermal energy’s renewable nature with minimal emissions compared to fossil fuels has led to valuable polygeneration models in geothermal-rich regions, promoting energy sustainability. Key challenges include improving integrated structures due to these resources’ low/medium temperature nature and assessing the feasibility of producing essential products (e.g., hydrogen and methanol), typically produced in structures with substantial pollution. The proposed system’s innovations focus on reducing irreversibility through thermal integration, introducing a negative CO2 emission structure, and utilizing CO2 hydrogenation based on geothermal energy for methanol production. Hence, the system encompasses a geothermal power plant, a Goswami cycle, a direct hydrogenation methanol synthesis unit, and a proton exchange membrane electrolyzer. The findings show generating methanol at a rate of 0.85 kg/s, domestic hot water at a rate of 2.231 kg/s, chilled water at a rate of 3.931 kg/s, and electric power at a capacity of 21,530 kW. Hence, the system’s thermal, electrical, and exergy efficiencies are determined to be 7.54 %, 3.87 %, and 47 %, respectively. Furthermore, the sum unit cost of products and the levelized energy cost equal 0.0272 $/GJ and 0.17 $/kWh, correspondingly. Additionally, a net present value of 65.86 M$ and a total yearly cost of 37.52 M$ are the results of the economic assessment. The current research demonstrates a negative CO2 emission from an environmental standpoint. The attainment of negative CO2 emissions is due to using CO2 as input material in the system. Also, the system’s net present value surpasses the total annual cost by 1.75 times, mainly due to its ability to produce products like methanol, generating revenue to offset initial costs. The proposed system is ideal for geothermal energy sites near seawater, promoting environmental preservation by reducing pollutants. Finally, it is suggested that the system’s operation be optimized and an experiential setup be used for future research.

Innovative modification process of a natural gas power plant using self-sufficient waste heat recovery and flue gas utilization for a CCHP-methanol generation application: A comprehensive multi-variable feasibility study

Waste heat recovery holds significant importance in the context of natural gas power plants, as it facilitates the utilization of energy loss, leading to enhanced overall performance and mitigating adverse environmental effects. By harnessing and employing waste heat, power plants possess the capability to modify and optimize their operation, making a substantial contribution toward sustainable power/energy generation. Therefore, this study proposes a novel and eco-friendly approach to utilizing the flue gas emitted by a natural gas power plant. In addition to recovering waste heat, this method involves harnessing the flue gas for methanol production. The proposed system consists of an organic Rankine cycle, and absorption chiller, heating provider units, an electrolyzer for hydrogen generation, and a methanol synthesis unit. The novel method is implemented through computer-aided simulation using the Aspen HYSYS software and is subjected to an extensive analysis encompassing energy, exergy, environmental, and economic viewpoints. The simulation results exhibit producing 2712 kg/h of methanol with a purity of 99.97 mol%, 395.67 kg/s of hot water, 378 kg/s of chilled water, and 12253.57 kW of power. In this process, the energy and exergy efficiencies are 94.35% and 31.74%, respectively. Parametric study results demonstrate that reducing the gas turbine pressure and increasing the working fluid temperature in the evaporator of the absorption chiller cycle leads to improved exergy efficiency. Moreover, the multigeneration scenario shows a carbon dioxide footprint of 0.1564 kg/kWh and a total unit cost of product of 0.0485 $/GJ.

Optimized scheduling of virtual plants with bio gas and electrohydric alcohol based on stepped carbon transactions

In order to reduce carbon emissions and promote clean energy development and utilization, a virtual plant optimization scheduling strategy for bio gas coupled to methanol synthesis units based on a stepped carbon transaction mechanism is proposed. This strategy is based on the transportation cost of hydrogen energy storage and the reality that methanol is widely used in the industry, to construct a second-order variable pressure adsorptive bio gas and electro alcohols linked production model, to extract high purity natural gas and CO2, and to couple the methanol synthesis unit with the bio gas equipment, while introducing a stepped carbon trading mechanism to realize CO2 recycling and wind with the lowest running cost in a virtual power plant Efficient dissipation of photogenerated electrical energy. Finally, by setting up different scenarios and conducting computational validation, the analytical results confirm that the proposed model strategy can meet the demands of low carbon and economy in virtual power plants.

Multi-variable study of a novel multigeneration system using biogas separation unit and LNG cold energy utilization, producing electricity, cooling, heat, fresh water, liquid CO2, biomethane, and methanol

Biogas fuel has gained recognition as a highly suitable alternative to fossil fuels, attributed to its renewable nature and remarkable energy density. Biogas fuel utilization facilitates the integration of combined energy systems equipped with multi-generational structures, rendering them suitable for long-term planning and management. Hence, this study presents a unique approach to using biogas for multigeneration, exhibiting enhanced thermodynamic efficiencies and negative carbon dioxide emissions. To achieve the stated objective, an innovative system is devised that involves the utilization of a biogas separation unit in integration with several other components, including a LNG cold energy utilization unit, an ammonia Rankine cycle, a desalination unit, a Kalina cycle, a solid oxide electrolyzer cell, a biomethane combined cycle, and a methanol synthesis unit. The newly devised configuration is simulated through the Aspen HYSYS software and assessed from energy, exergy, environmental, and economic considerations. Based on the research findings, the suggested methodology exhibits energy and exergy efficiencies of 91% and 83%, correspondingly. Furthermore, the evaluation of the entire unit cost of the product and the levelized energy cost reveals values of 4.81 $/GJ and 0.033 $/kWh, respectively. The carbon dioxide emission intensity of the newly implemented process is calculated to be − 0.1041 kg/kWh. The economic aspects reveal a favorable net present value of 1470.6 M$ and a payback period of 5.29 years.

Numerical simulation and 4E analysis of a steam methane reforming-based multi heat recovery process, producing electricity, methanol, fresh water, heating, and coolant

Natural gas power plants play a pivotal role in power generation; nevertheless, their waste heat contributes to diminished thermodynamic efficiencies and the release of carbon dioxide emissions. One primary approach involves implementing effective heat recovery strategies to generate various products. The present study suggests a novel approach to heat recovery in different stages utilizing series and parallel arrangements within an environmentally friendly design to enhance controllability while expanding the range of products. The present study includes a steam methane reforming process, a Kalina cycle, a multi-effect desalination unit, a methanol synthesis unit, two organic Rankine cycles, and two ammonia Rankine cycles. The primary objective of this system is to efficiently and concurrently produce electricity, hot water, chilled water, fresh water, and methanol. The findings reveal that the newly devised process exhibits energy and exergy efficiencies of 47.55% and 50.58%, respectively, while the total unit cost of products amounts to 7.69 $/GJ. From an environmental perspective, the results indicate that the proposed structure exhibits a total net emission of 87.1 × 103 kg/h and a CO2 footprint of 0.22 kgCO2/kWh. Ultimately, the economic assessment elucidates that the fixed investment cost, total investment cost, total annual cost, and net present value are equivalent to 373.0 M$, 496.1 M$, 207.5 M$, and 598.6 M$, respectively.

Comprehensive technical study of a novel polygeneration arrangement using natural gas power plant and geothermal energy for producing electricity, heat, fresh water, and methanol

Structural modifications play a crucial role in enhancing the sustainability of natural gas power plants owing to their significant contribution to greenhouse gas emissions and irreversibility factors. One primary solution is using waste heat recovery systems integrated with these power plants, producing different products. Furthermore, integrating renewable energy resources into the entire system within a co-feed framework may be a viable method for further enhancements. The current study focuses on a novel heat integration process combined with a natural gas power plant, which uses geothermal energy as an auxiliary energy source. The newly designed system encompasses a gas turbine cycle, two modified geothermal power plants, a water electrolyzer unit, and a methanol synthesis unit. The process is simulated utilizing the Aspen HYSYS software, and to evaluate its viability, analyses are performed pertaining to energy, exergy, environment, and economics. Furthermore, a comprehensive parametric analysis is conducted on the primary performance indicators. The simulation results show that the process’s energy, exergy, and electrical efficiencies equal 53.85%, 47.30%, and 40.26%, respectively. The environmental evaluation demonstrates that the specific carbon dioxide emissions associated with the total energy produced and the sum of power and heating are 0.27 kg/kWh and 0.294 kg/kWh, respectively. From the economic aspect, the total unit cost of the products and the cost of energy of the system are 20.69 $/GJ and 0.086 $/kWh, respectively. Also, total annual cost, investment cost, and net present value of 222.81 M$, 1010.64 M$, and 1220.57 M$, respectively.

Proposal and comprehensive study of an integrated polygeneration process relying on landfill gas, renewable hydrogen, and binary geothermal cycle

Landfill gas (LFG) is an accessible, inexpensive, and carbon-rich source, and due to its methane content, it can also be used as a fuel. In this paper, a novel polygeneration structure is presented that uses LFG as the input fuel as well as geothermal energy to produce valuable products, including electricity, methanol, freshwater, heating, and cooling. The configuration is made of biogas combustion unit, binary geothermal power plant, cooling water production unit, Kalina power cycle, desalination unit, water electrolysis unit, and methanol synthesis and purification unit. The methanol synthesis unit is modified using a scrubbing column, resulting in recovery of methanol without loss. Aspen HYSYS application is used to model this procedure, and it is examined from a 4E (energy, exergy, economic, and environmental) standpoint. The findings show that a total of55.46% of energyand 77.29% of exergy efficienciesare reached. From the environmental standpoint, it is found that the proposed structure has negative emissions, and its carbon dioxide (CO2) footprint is equal to −0.161 kgCO2/kgprod. In addition, the total CO2 emission of 46,780 kg/h is calculated. Concerning the economic aspect, the cost rate of produced methanol, heating, cooling, and freshwater are found at 0.268 $/kgMeOH, 1.01 $/kgLPS, 0.26 $/kgCW, and 0.7 $/kgFW, respectively. Besides, it is concluded that the methanol production cost rate of this model is comparatively lower than the methods such as power-to-methanol and coke oven gas-to-methanol.

Cost-optimal Power-to-Methanol: Flexible operation or intermediate storage?

The synthesis of methanol from captured carbon dioxide and green hydrogen could be a promising replacement for the current fossil-based production. The major energy input and cost driver for such a process is the electricity for hydrogen production. Time-variable electricity cost or availability thus motivates flexible operation. However, it is unclear if each unit of the process should be operated flexibly, and if storage of electricity or hydrogen reduces the methanol production cost. To answer these questions, we modeled a Power-to-Methanol plant with batteries and hydrogen storage. Using this model, we solved a combined design and scheduling optimization problem, which provides the optimal size of the units of the plant and their optimal (quasi-stationary) operation. The annualized cost of methanol was minimized for a grid-connected and a stand-alone case study considering current and future (2030) unit cost scenarios. The optimization results confirm that storage, especially hydrogen storage, is particularly beneficial when the electricity price is high and highly fluctuating. In future unit cost scenarios, batteries could play an even bigger role due to the expected significant cost reduction. Irrespective of the presence of storage, the whole Power-to-Methanol plant should be operated flexibly: even moderate flexibility of the methanol synthesis unit significantly reduces the production cost.

A novel process for the simultaneous production of methanol, oxygen, and electricity using a PEM electrolyzer and agricultural-based landfill gas-fed oxyfuel combustion power plant

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 CO2 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 CO2 emission of this process is negative and equals −0.97 kgCO2/kgMeOH, 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 $/ kgMeOH respectively.

Design, thermodynamic and economic evaluation, and optimization of gasoline production from refinery furnaces flue gas

In this paper, the conversion of refinery furnaces’ flue gas into gasoline through the MTG process is investigated. This approach not only reduces greenhouse gas emissions, but also produces a high-value product, providing economic incentives to adopt this technology. The proposed integrated system comprises an organic Rankine cycle, an amine-based carbon capture unit, a methanol synthesis unit, and an MTG unit. In this study, we evaluated the technical and economic aspects of this conversion process, including the thermodynamic and cost analysis, to assess its viability as a sustainable solution for mitigating CO2 emissions from refineries. Also, using response surface methodology combined with the Box-Behnken design, the proposed integrated system was optimized to minimize the gasoline production cost. The thermodynamic assessment concludes that the energy and exergy efficiencies of the overall system are 73.12% and 85.24%, respectively. The proposed system yields an annual gasoline production rate of >184 million liters. The estimated total capital investment for the proposed system is 172.16 M$, which the methanol synthesis unit with a share of 48.65% is the most expensive one. The results give a gasoline production cost of 1.58 $/kg or 4.28 $/gal for the optimized case. Also, hydrogen has the highest contribution in the production cost, so with a 20% decrease in the price of hydrogen, the production cost of gasoline decreases by 18.71%. With this rate of technological improvement, reductions in the price of hydrogen seem inevitable in not-so-distant years, which makes the proposed system of converting refinery furnaces’ flue gas into gasoline became desirable.

Comprehensive analysis of a novel power and methanol coproduction process using landfill gas reforming and renewable hydrogen generation by an alkaline electrolyzer

This research presents a unique method for producing electricity and methanol simultaneously using landfill gas reforming and renewable hydrogen production. The suggested procedure offers a cheap cost of production, high energy and energy efficiency, and net zero carbon dioxide emissions. Alkaline electrolyzers, biogas partial oxidation reforming units, gas-steam cycle power plants, steam cycle power plants, and methanol synthesis units make up the recommended procedure. Findings revealed that the novel procedure's overall energy and exergy efficiencies are 48.71% and 53.62%, respectively. Additionally, it was shown that the gas-steam cycle power plant makes the largest contribution (56%) to the total exergy destruction (94403.36 kW), while the biogas partial oxidation reforming unit makes the smallest contribution (7%). The energy efficiencies of the biogas partial oxidation reforming unit, alkaline electrolyzer, gas-steam cycle power plant, steam cycle power plant, and methanol synthesis unit are also based on the completed studies and are, respectively, 82.12%, 85.06%, 76.59%, 19.78%, and 93.14%. The environmental analysis illustrated that using the steam cycle power plant and gas-steam cycle power plant as well as integrated employment of heat sources are the main factors for achieving negative net carbon dioxide emission (−0.054 kgCO2kgMeOH), and the process has a significant advantage. Finally, the economic analysis revealed that the total cost of produced methanol equals 0.362 USDkg, which is lower than similar processes.

Simulation and 4E analysis of a novel coke oven gas-fed combined power, methanol, and oxygen production system: Application of solid oxide fuel cell and methanol synthesis unit

To address an innovative trigeneration process using coke oven gas as the input fuel, a novel heat integration process based on a solid oxide fuel cell is designed and discussed in the current research. Since the coke oven gas is a hydrogen-enriched fuel, its application in a solid oxide fuel cell power plant can improve sustainability and environmental indexes. The flue gas leaving the fuel cell subsystem is directed to a Kalina power cycle and an absorption power cycle for heat recovery, wherein additional power is available. Accordingly, the rejected flue gas is sent into a methanol synthesis unit for producing methanol. A part of generated electric power is delivered to a proton electrolyte membrane electrolyzer, where the water electrolysis process generates hydrogen and oxygen. Here, the generated hydrogen is delivered to the methanol synthesis unit. This system is simulated in the Aspen HYSYS software. To study the designed system, energy, exergy, environmental, and economic assessments are considered. In addition, a sensitivity study based on the main variables is performed. According to the results, the energy and exergy efficiencies of the whole structure are 34.69% and 88.885, respectively. In addition, the methanol production cost was 0.595 $/kg. The CO2 emission intensity is found to be 0.18 kgCO2/kgMeOH. So, the use of coke oven gas reduced the environmental threats considerably.

Proposal of a biogas upgrading process for a novel eco-friendly trigeneration model, producing power, methanol, and desalinated water

Non-renewability and difficult access to fossil fuels can be replaced with renewable fuels, such as biogas. Due to the close structure of biogas to fossil fuels, it has become a powerful fuel for energy systems, especially when it enters the upgrading process. With this in mind, the proposed system proposes a novel trigeneration model integrated into a biogas upgrading unit, producing electricity, desalinated water, and methanol. This process is proposed for the first time, which is able to increase the thermodynamic, economic, and environmental performances compared to previous studies. Negative CO2 emission is its main feature that is available using a methanol synthesis unit. Thermal desalination and ammonia Rankine cycles are other equipment used in the proposed structure. The whole system is simulated in the Aspen HYSYS software and is investigated from the 4E aspect, namely energy, exergy, economics, and environment. Also, a sensitivity study is conducted. The overall energy and exergy efficiencies equal 51.54% and 87.39%, respectively. These criteria are improved between 4.54% and 15.64%-points and 32.29–74.70%-point compared to the existing literature review, respectively. In addition, the net CO2 emission intensity equals −0.54 kgCO2/kgMeOH, which is considerably lower than other relevant technologies (between 1.78 and 10.68 times). Moreover, the unit cost of methanol in the proposed process equals 0.21 $/kg, which is 63.54–85.61% lower than other methods available in the literature review.

Effects of Steam-To-Biomass Ratio and Temperature in Gasification on The Methanol Conversion and Selectivity: A Simulation Study of Biomass to Methanol

Gasification is an attractive pathway for valorizing waste and biomass as it can deal with a wide range of feedstocks yielding gaseous products that be converted further to valuable biofuels and chemicals. While many previous studies commonly discussed the effects of gasification operating parameters, such as operating conditions, biomass feedstocks and gasifying agents, on syngas compositions, fewer studies evaluated the effects of gasification process parameters on final products derived from syngas. Essentially, performing an integrated assessment of the biomass-to-product conversion gives a thorough understanding of the biomass processing and provides one with useful heuristics for the conversion of biomass to valuable chemicals. This study evaluates the effects of steam-to-biomass ratio (S/B = 0.3 – 0.7) and gasification temperature (Tgasif = 900℃ – 1,100℃) on the methanol production by performing simulations in the Aspen Plus v.11 process simulator. The kinetically controlled reactions model was considered in the methanol synthesis unit to mimic its actual process condition and to take into account the possibility of the side product formation. The outcome of this study recommends that the steam-to-biomass ratio gives more notable effects on the gasification distribution products and the conversion of syngas to methanol than those given by the gasification temperature. While, the reaction selectivity to methanol remains high, and it is not sensitive to the change of steam-to-biomass ratios and gasification temperatures.

Chemical absorption-based biogas upgrading process integrated with a novel poly-generation system: Application of Aspen HYSYS simulation and 4E study

In this paper, an integrated poly-generation process using biogas for the simultaneous production of useful products, including methanol (0.745 kmolMeOh/kmolbiogas), liquid carbon dioxide, CO2, (11.39 m3/h), desalinated water (34.19 m3/h), and heating (23.31 tonLPS/h) is simulated in the Aspen HYSYS software. Due to the feasibility of increasing the methane content of the biogas, the current study is motivated to upgrade the existing biogas stream through a chemical absorption process toward a novel poly-generation model. Hence, an innovative heat integration is arranged, where the arranged system is made of a chemical absorption unit, a biomethane reforming unit, an integrated CO2 compression unit, an ammonia Rankine cycle, a modified organic Rankine cycle, an integrated synthesis gas compression unit, a methanol synthesis unit, and a water desalination unit. The arranged model is analyzed from the 4E perspective (energy, exergy, economic, and environmental), and a comprehensive parametric study is also done. It is demonstrated that the energy and exergy efficiencies of the newly designed model are found as 54.79%, and 61.54%, respectively. In addition, the exergy analysis shows that the total exergy destruction rate equals 74795 kW, to which the biomethane reforming unit has the largest contribution (40%). The CO2 emission intensity corresponding to the model is also calculated to be 1.33 kgCO2/kgMeOh, which is lower compared to that of coal-to-methanol and steam methane reforming methods. Besides, the total annual cost and total product cost of the model are 166732539 $/year and 0.78 $/kgMeOh, respectively. According to the parametric study, methanol production and overall energy efficiency enhance with increasing the gases recycled to the methanol synthesis reactor and the methanol production cost reduces.

A novel structure of natural gas, electricity, and methanol production using a combined reforming cycle: Integration of biogas upgrading, liquefied natural gas re-gasification, power plant, and methanol synthesis unit

A novel structure of natural gas, electricity, and methanol production using a combined reforming cycle: Integration of biogas upgrading, liquefied natural gas re-gasification, power plant, and methanol synthesis unit

Simulation of and multi-aspect study of a novel trigeneration process for crude helium, liquefied natural gas, and methanol production; operation improvement and emission reduction

This study suggested a novel integrated trigeneration system for crude helium (He), liquefied natural gas, and methanol production. This proposed system consisted of a cryogenic-based helium recovery unit from natural gas, a syngas synthesis unit by hybrid reforming, a methanol synthesis unit, and a sour water recovery unit. Comprehensive energy, exergy, environmental, and economic analyses were performed to assess the system’s performance. Based on the results, the crude helium, liquefied natural gas, and methanol production rates were obtained to be 4105kg/h, 3594000kg/h, and 707800kg/h, respectively. These production rates provided 93.4 % and 94.38 % overall exergy and energy efficiencies. Also, over 60 % of the total exergy destruction occurred in reactors (R1-R4). The application of sour water recovery supplied 85.66 % of the reforming and methanol synthesis process. Regarding environmental analysis, 94 % of the CO2 emission was due to the indirect mode, and the rate of the CO2 emission was estimated to be 0.164 kgCO2/kgprods. Finally, the economic analysis indicated that the total annual production costs were about 440.16 M$ and 0.13 USD/kg. Therefore, the net present value of the designed scheme was estimated to be 364.36 M$.

Thermodynamic and Economic Evaluation of a Novel Green Methanol Poly-Generation System

Methanol is considered a sustainable alternative energy source due to its ease of storage and high-octane rating. However, the conventional methanol production process is accompanied by resource consumption and significant greenhouse gas emissions. The electrochemical reaction of electrochemically reacted hydrogen (H2) with captured carbon dioxide (CO2) offers an alternative route to methanol production. This paper presents a new green poly-generation system consisting of a parabolic trough solar collector (PTC) unit, an organic Rankine cycle (ORC) unit, a CO2 capture unit, an alkaline electrolysis unit, a green methanol synthesis and distillation unit, and a double-effect lithium bromide absorption refrigeration (ARC) unit. The system mainly produced 147.4 kmol/h of methanol at 99.9% purity, 283,500 kmol/h of domestic hot water, and a cooling load of 1341 kW. A total 361.34 MW of thermal energy was supplied to the ORC by the PTC. The alkaline electrolysis unit generated 464.2 kmol/h of H2 and 230.6 kmol/h of oxygen (O2) while providing H2 for methanol synthesis. Thermodynamic and economic analysis of the system was carried out. The energy and exergy efficiency of the whole system could reach 76% and 22.8%, respectively. The internal rate of return (IRR) for the system without subsidies was 11.394%. The analysis for the methanol price showed that the system was economically viable when the methanol price exceedsed$363.34/ton. This new proposed poly-generation system offers more options for efficiently green methanol production.