Search

This study aims a techno-economic analysis of a plant that produces methanol by hydrogenating carbon dioxide in the waste gas from an oil refinery using the electricity from floating photovoltaic power plant. First, carbon dioxide in the flue gas is captured in the carbon capture plant (CCP), and the hydrogen obtained from the seawater in the hydrogen plant (HP) with the help of photovoltaic energy is combined in the methanol plant (MPP) to produce methanol fuel. Using the Engineering Equation Solver (EES), a calculation was made of the amount of energy required and the number of solar panels or wind turbines that would be required to meet this demand, and then the environmental impact of the methanol plant was investigated. The Libyan Az-Zawiya oil refinery was considered for the case study due to its high solar potential, proximity to the sea and energy security. Systems' processes for CO 2 emissions, heat integration, energy efficiency, and thermo-economic performance were all taken into consideration. Renewable energy, synthetic fuel, and the methanol plant showed efficiencies of 0.21%, 0.5872%, and 0.1626%, respectively, and at the optimum density of the electrolyzer, 2.2 kA/m2, the efficiency of the electrolyzer was 0.782%. According to this study, all output parameters increase with the increase in the flue gas in the process, showing that flue gas is the most important input parameter affecting the outputs. The total cost of the plant for 30 years of operation was found to be $11.350 billion, with a production capacity of over 43.360 million tons of methanol, which equates to $412.9 per ton and $0.4129 per kg. Environmentally, the rate of captured emissions was about 4890 tons per day, and the mitigation rate was approximately 4513 tons per day. According to the results, the current plant is competitive with other clean synthetic fuel production plants. • High CO2 reduction potential. • Renewable hydrogen and methanol production. • On-demand hydrogen generation is provided with PEM electrolysis. • Hydrogen generation costs are competitive with other methods. [ABSTRACT FROM AUTHOR]

Carbon capture and carbon reuse in the chemical plants is one of the attractive prospective approaches to decrease the concerns about global warming and climate change. In the present study, is focused on the synthesis gas production from carbon dioxide in a methanol synthesis plant. In this regard, two methanol processes are proposed based on CO 2 separation, recycling, and reforming. In the first scenario, CO 2 is separated and recycled to the conventional reformer, while the process is equipped by a CO 2 separation unit and dry methane reformer in the second scenario. The proposed processes are simulated and a sensitivity analysis is performed to investigated the effect of inputs on methanol productivity and carbon conversion. The operational parameters of proposed processes are optimized to enhance methanol productivity and CO 2 conversion. Then, the processes are compared from energy efficiency, carbon efficiency, CO 2 emission rate and methanol productivity viewpoints. The results showed that, in the second proposed scenario, methanol production rate approach to 5367 tons per day in comparison to 5030 tons per day for industrial unit. In addition, modification of conventional methanol process based on the second scenario could decrease CO 2 emission rate about 56 tons per day. [Display omitted] • Two novel methanol synthesis techniques based on CO 2 separation, recycling, and reforming were simulated. • A comparison was made between the industrial unit and two proposed configurations from the environmental and process aspect. • Various effects of operating conditions on the methanol production rate and CO 2 emissions were evaluated. • A sensitivity analysis was performed, and operational parameters were optimized to improve the proposed systems' performance. [ABSTRACT FROM AUTHOR]

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]

• A bio-process model for combined methanol and power production from bio-oil is proposed. • The cleanest possible bio-process was proposed using optimization by GA. • 70.6 % reduction in GWP through rigorous optimization and waste heat recovery was achieved. • 15.1 % increase in annual economic return rate under optimal operation was achieved. • 2.176 Mton/year reductions in CO 2 emissions per % of the methanol market gained can be achieved. Traditional methanol production from natural gas is well-studied, but there is a lack of research on environmentally optimizing bio-based methanol production. This study focuses on optimizing the combined production of bio-methanol and power from bio-oil using a comprehensive bio-process model. The research includes a novel framework for environmental, technical, and economic optimization of bio-oil to methanol and power to determine the most eco-friendly and cost-effective approach. An organic Rankine cycle (ORC) is also integrated for waste heat recovery. The results of this study revealed that the bio-based process with ORC showed a 22.6 % reduction in global warming potential impact (GWP) per kilogram of methanol, compared to the bio-based process without ORC. Also, by implementing the most environmentally friendly process, GWP will be reduced by 70.6 % per kg methanol compared to base sub-optimal operation. The results showed that for the process with the addition of ORC, after performing multi-objective optimization, under the optimal conditions, the economic annual rate of return increased from 19.6 % to 34.7 %. Finally, it was revealed that if the considered technology is commercialized, for every percentage of the methanol market it gains, it will contribute to 2.176 million tons CO 2 -eq/year less emissions. [ABSTRACT FROM AUTHOR]

[Display omitted] • One traditional and three novel biomass-to-methanol (BTM) processes are proposed. • Clean H 2 production pathways are used to maximize carbon utilization potential. • Novel BTM processes all enhance methanol production and carbon mitigation. • Integration of methane pyrolysis pathway is preferred in technical performances. • Deployment of methane chemical looping pathway shows stronger economic advantages. Concerns about depleted fossil fuels and the climate crisis have intensified the interest in producing biomass-derived methanol. However, the traditional biomass-to-methanol (BTM) process suffers from low carbon conversion ability and serious CO 2 emissions caused by the water–gas-shift (WGS) unit. In this study, three novel BTM processes coupled with solid oxide electrolysis, methane pyrolysis, and methane chemical looping technologies are proposed to eliminate WGS unit, and the systematic heat integration is considered to achieve energy cascade utilization. Meanwhile, process performances are comprehensively evaluated to compare the technical, economic, and environmental attractiveness of three novel BTM processes. It is found that compared with the original BTM process, three novel processes significantly improve carbon efficiency by 22%. Meanwhile, CO 2 emissions are reduced by 60%. Moreover, the application of methane chemical looping technology is more economical, and the associated net production cost decreases by more than 30%. Additionally, the BTM process coupled with solid oxide electrolysis is more environmentally friendly, whereas the process with methane pyrolysis technology is more exergy-efficient. Overall, the integrated processes have significant application prospects for carbon conversion and mitigation ability as well as economic attractiveness. [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]

• Developed a generalized optimization framework that integrates reaction pathways and downstream separation network optimization, enabling the optimal product/raw material and associated process flowsheet identification. • Three case studies are solved, including both multistep chemical production and utilization problems. • The framework empowers the process industry to determine optimal sustainable and profitable processes for the upstream, intermediate, and downstream stages, offering valuable preliminary insights for early-stage decision-making. Reducing the environmental impact of chemical production has become a critical objective due to carbon emission regulations and the challenges the carbon market poses. Downstream separation network optimization, which can improve process sustainability by using complex heat exchanger networks, applying advanced separation techniques, optimizing the design/operating parameters, etc., has been researched for many years. However, most optimization work focuses solely on downstream separation sections without considering the selection of raw materials and different reaction pathways. This work aims to develop a mixed integer nonlinear programming (MINLP) optimization model, which integrates reaction pathway selection and downstream separation optimization, to select the optimal sustainable process route for utilizing raw materials or producing products. The objective is to maximize/minimize the process profit/cost. Decision variables such as binary variables, which represent the selection of separation task, key component, heating utility, and continuous variables, which influence the separation mass/energy balance, are considered. By giving parameters like reaction conversion rate, selectivity, and raw material/product price, this optimization model can identify the optimal process route for producing a target product or utilizing a raw material. The optimization model was applied to two case studies: one-step isobutylene and methanol utilization and two-step 1,4-butanediol (BDO) production. The process routes, using isobutylene for pivalic acid production and methanol for gasoline production, have the highest process profit per carbon emission. And the process route, which uses acetylene for BDO production, leads to minimum process cost. [ABSTRACT FROM AUTHOR]