Reaction Of Methanol Research Articles

A highly efficient Li–Cu/MoOx catalyst constructed by a precursor dispersion and alkali metal-promotion stepwise regulation strategy for the CO2 hydrogenation to methanol reaction

The hydrogenation of CO2 enables the production of high-value fuels and chemicals, contributing to a sustainable and environment-friendly energy transition.

Low-temperature fabrication of potassium single-atom solid base catalysts with high activity in transesterification

Solid base catalysts are appealing to a variety of reactions due to their benefits of easy separation, negligible corrosion, and environmental friendliness. However, their activity is compromised because high temperature is frequently required for the formation of basic sites and aggregation of basic components is easy to occur under those circumstances. Herein, K single-atom solid base catalysts were fabricated by a low temperature, pyrolysis-free, grafting strategy, resulting in the catalysts with highly dispersed basic sites and high activity in transesterification reaction. Potassium tert-butoxide (KTB) functions as the precursor and mesoporous silica SBA-15 is employed as the support, K atoms are successfully grafted onto SBA-15 (denoted as K1/SBA-15) at 30 °C. Various characterizations confirm that highly dispersed K single atoms exist in the form of K-O-Si. The amount of basic sites of K1/SBA-15 measured by titration is 1.62 mmol·g−1, verifying the basicity of the obtained catalyst. K1/SBA-15 shows excellent activity (49.1 % yield) in the transesterification reaction of ethylene carbonate (EC) and methanol to produce dimethyl carbonate (DMC), which is superior to typical alkali metal-related solid superbases. The catalyst was recovered after reaction and the yield of DMC over the recovered catalyst decreases slightly (43.4 %) due to the partial deformation of pores. Moreover, the K1/SBA-15 exhibits a turnover frequency (TOF) value of 82.5 h−1, obviously higher than various reported solid base catalysts (0.95–36.2 h−1) under semblable reaction conditions.

High-Performance Hydrogen-Selective Pd-Ag Membranes Modified with Pd-Pt Nanoparticles for Use in Steam Reforming Membrane Reactors.

A unique method for synthesizing a surface modifier for metallic hydrogen permeable membranes based on non-classic bimetallic pentagonally structured Pd-Pt nanoparticles was developed. It was found that nanoparticles had unique hollow structures. This significantly reduced the cost of their production due to the economical use of metal. According to the results of electrochemical studies, a synthesized bimetallic Pd-Pt/Pd-Ag modifier showed excellent catalytic activity (up to 60.72 mA cm-2), long-term stability, and resistance to COads poisoning in the alkaline oxidation reaction of methanol. The membrane with the pentagonally structured Pd-Pt/Pd-Ag modifier showed the highest hydrogen permeation flux density, up to 27.3 mmol s-1 m-2. The obtained hydrogen flux density was two times higher than that for membranes with a classic Pdblack/Pd-Ag modifier and an order of magnitude higher than that for an unmodified membrane. Since the rate of transcrystalline hydrogen transfer through a membrane increased, while the speed of transfer through defects remained unchanged, a one and a half times rise in selectivity of the developed Pd-Pt/Pd-Ag membranes was recorded, and it amounted to 3514. The achieved results were due to both the synergistic effect of the combination of Pd and Pt metals in the modifier composition and the large number of available catalytically active centers, which were present as a result of non-classic morphology with high-index facets. The specific faceting, defect structure, and unusual properties provide great opportunities for the application of nanoparticles in the areas of membrane reactors, electrocatalysis, and the petrochemical and hydrogen industries.

Computational study of added H2 impacts on mixture formation, OH radical and unregulated emissions of spark-ignition methanol engine under various boundary parameters

Numerical simulations of hydrogen (H2) impacts on mixture formation, OH radical generation, and formaldehyde (HCHO) and unburned methanol (CH3OH) emissions of spark-ignition (SI) methanol engine based methanol late-injection strategy under different methanol injection timings (MIT), ignition timings (IT), excess air ratios (λ) and added H2 ratios (RH2) boundary parameters were conducted. The simulation results show that the ideal methanol concentration distribution is obtained at the MIT = 85°CA BTDC. The OH radical plays a dominant role in methanol oxidation. The OHPMF (peak OH radical mass fraction) of RH2 = 9 % ≫ OHPMF of RH2 = 6 % > OHPMF of RH2 = 3 % > OHPMF of RH2 = 0 % at MIT = 85°CA BTDC. Compared with IT and λ, the RH2 is more decisive for the generation of OH radical. The HCHO is a major intermediate and an important unregulated emission of methanol engine. In the initial stage of methanol reaction, added H2 can accelerate the generation of OH radical, further promote the oxidation of methanol, and greatly raise the generation of HCHO. The peak HCHO mass fraction increases with the increase of RH2. At MIT = 85°CA BTDC and exhaust valve opening, the HCHO emission of RH2 = 3 %, 6 %, and 9 % is approximately 51 %, 76.5 % and 89.4 % lower than that of RH2 = 0 %, respectively. The generation and post-oxidation of HCHO mainly depended on average in-cylinder temperature. There is a lowest CH3OH emission at MIT = 85°CA BTDC, IT = 28°CA BTDC, λ = 1.4 and pure methanol. At MIT = 85°CA BTDC, λ = 1.4 and exhaust valve opening, the CH3OH emission of RH2 = 3 %, 6 %, and 9 % is approximately 52.8 %, 75.5 % and 92.5 % lower than that of RH2 = 0 %, respectively.

Nonlinear Behavior of Methanol Synthesis Compared to CO2 Methanation

AbstractThe nonlinear behavior of CO2 methanation over a Ni‐catalyst is compared to methanol synthesis over a standard Cu/ZnO‐catalyst in a continuous stirred tank reactor (CSTR). Both reactions have received a lot of attention these days for chemical energy storage. Both reactions are exothermic but behave in a different way. CO2 methanation is known to be strongly exothermic, giving rise to multiple steady states. This behavior is induced by the self‐acceleration of the methanation reaction because the heat production of the chemical reaction increases with rising temperature. It is shown that methanol synthesis behaves fundamentally different under the operating conditions usually employed in practice. It is less exothermic but, even more important, the overall heat production of the methanol reaction system decreases with increasing temperature, giving rise to a unique and stable steady state. This insight is obtained with an extension of the classical graphical analysis with heat production and heat removal curves.

Mechanistic Insight into Acceptorless Dehydrogenation of Methanol to Syngas Catalyzed by MACHO-Type Ruthenium and Manganese Complexes: A DFT Study.

The acceptorless dehydrogenation of methanol to produce carbon monoxide (CO) and dihydrogen (H2) mediated by MACHO-type 1-Ru and 1-Mn complexes was theoretically investigated via density functional theory calculations. The 1-Ru-catalyzed process involves the formation of active species 4-Ru through a methanol-bridged H2 release pathway. Methanol dehydrogenation by 4-Ru yields formaldehyde and 1-Ru, followed by H2 release to regenerate 4-Ru (rate-determining step, ΔG‡ = 32.5 kcal/mol). Formaldehyde further reacts with methanol via nucleophilic attack of the MeO- ligand in the Ru complex (ΔG‡ = 9.6 kcal/mol), which is more favorable than the traditional methanol-to-formaldehyde nucleophilic attack (ΔG‡ = 33.8 kcal/mol) due to the higher nucleophilicity of MeO-. CO is ultimately produced through the methyl formate decarbonylation reaction. Accelerated H2 release in the early reaction stage compared to CO results from the initial methanol dehydrogenation and condensation of formaldehyde with methanol. In contrast, CO generation occurs later via methyl formate decarbonylation. The 1-Mn-catalyzed reaction has reduced efficiency compared to 1-Ru for the higher Gibbs energy barrier (ΔG‡ = 34.1 kcal/mol) of the rate-determining step. Excess NaOtBu promotes the reaction of CO and methanol, forming methyl formate, significantly reducing the CO/H2 ratio as the catalyst amount decreases. These findings deepen our understanding of the methanol-to-syngas transformation and can drive progress in this field.

Cr2 O3 Promoted In2 O3 Catalysts for CO2 Hydrogenation to Methanol.

Cr2 O3 was applied to study the modification of In2 O3 based catalysts for CO2 hydrogenation to methanol reaction. Combined with X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy (XPS), etc., the structure of the catalysts was characterized. The reaction performances for CO2 hydrogenation to methanol were evaluated on a stainless-steel fix-bed reactor. The results showed that solid solutions were formed for the Cr2 O3 promoted In2 O3 catalysts. The important role of electronic interaction between Cr2 O3 and In2 O3 was revealed in the hydrogenation reaction. In1.25 Cr0.75 O3 sample exhibited the highest methanol yield, which was 2.8 times higher than that of pure In2 O3 . No deactivation was observed for In1.25 Cr0.75 O3 sample during the 50 hours of reaction. The improved catalytic performance may be due to the formation of the solid solutions and the highest amount of oxygen vacancies.

Improving energy enterprise efficiency: Multi-aspect assessment and financially-driven optimization of a tri-generation plant

This research delves into a comprehensive financial analysis and optimization of a tri-generation plant that integrates power generation, cooling capacity, and hydrogen production. The plant design encompasses an organic flash cycle, a two-phase ejector, and methanol steam reforming. Our investigation extends beyond thermodynamic evaluations, encompassing a thorough assessment of economic factors including energy economics, exergy-based financial metrics, and sustainability considerations. Moreover, we calculate critical financial indicators such as payback period and levelized costs to determine the economic feasibility of the tri-generation system. The study showcases the tri-generation system's ability to yield 32.58 kW of power, 246.5 kW of cooling capacity, and 12.56 kg/h of hydrogen in the base case configuration. Optimal energetic and exergetic efficiencies, along with a calculated payback period of 3.92 years, underscore the financial viability of the system. Through meticulous parametric studies, we uncover the intricate interplay between methanol molar ratios, reactor temperatures, and overall economic performance. This comprehensive financial profiling, when disclosed, could enhance regulatory oversight and shape financial supervision policies within the energy sector.

Synthesis of biodiesel from residual oil extracted from spent bleaching earth using spent bleaching earth-supported catalyst

Proper disposal of spent bleaching earth (SBE) is much anticipated to create a circular economy. In this study, a two-pronged approach was employed to utilise SBE from palm oil refinery for its suitability to act as second-generation biofuel feedstock and catalyst. The SBE was first wet-impregnated and doped with potassium hydroxide (KOH) to further enhance the catalytic activity. The hexane-extracted bleached oil of SBE at conditions of 40 g SBE, 1:4 ratio of oil to n-hexane, and 6 hr extraction time was subjected to different transesterification parameters i.e., catalyst loading, oil: methanol ratio, reaction temperature, and reaction time. The obtained catalysts were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy with energy dispersive X-ray, temperature programmed desorption of carbon dioxide (TPD-CO2) and Brunauer-Emmett-Teller (BET) techniques. The N2 adsorption-desorption and TPD-CO2 analyses indicated that SBE/KOH (600 °C) had the highest attainable BET surface area (22.62 m2/g) and basicity (25.82 cm3/g). SBE/KOH (600 °C) exhibited the highest biodiesel yield (80.3%) at the optimised reaction conditions: (80 °C, 2 wt% catalyst loading, 1:20 oil: methanol ratio and 2 h reaction time) compared to 67.3% via the unmodified control. The kinetics study revealed that the experimental results followed the first order reaction kinetics. The activation energy, enthalpy (ΔH) and entropy (ΔS) were determined to be 90.06 kJ/mol, 6.92 × 10−4 kJ/mol and −0.0414 kJ/mol K, respectively while the Gibbs free energy (ΔG) was 15.443 kJ/mol. Overall, SBE has enormous potential as one of the alternative sources for second-generation biofuel production.

Conventional vs. alternative biogas utilizations: An LCA-AHP based comparative study

This study compares the performance and the environmental impacts of three biogas utilization processes: combined heat and power cycle, dimethyl ether production, and methanol production. The processes are evaluated based on key performance indicators and life cycle assessments. Results show that molar methane conversion in the reforming unit is 93% for both dimethyl-ether (DME) and methanol processes. Methanol reactor reports a per-pass hydrogen conversion of 21%. DME production achieves an 89% conversion rate. The chemical pathways exhibit a 33% molar conversion of COx, contributing to the conversion of CO2 into advanced chemicals. The environmental footprint is evaluated through a life cycle assessment. Biogas cogeneration has the lowest global warming potential since DME and methanol production processes are influenced by steam production and electricity intake from the national grid, which relies on fossil fuels. An analytic hierarchy process is employed to assess the overall performance of the processes. DME production performs best with a score of 39%, followed by cogeneration with 31%, and methanol production with 30%. Different case studies are examined by modifying the weight criteria for each impact category. The findings provide that cogeneration and DME technologies perform better in all the iterations.

Molar ratio variation on high pressure methanol production: Quantitative safety analysis

The objective of this research was to conduct a quantitative safety analysis as well as estimate the possible risk of deaths due to methanol reactors at the Labuan process facility in Malaysia. The gathered outcomes included scenarios that occurred, such as toxicity, thermal radiation, and overpressure. The percentage of mortality was determined when a chemical mixture was discharged from nine plants in varying ratios of 1:3, 1:7, and 1:10, and at different operating pressures of 76, 184, and 331 bar, resulting in the occurrence of various events. ASPEN Hysys software was used to compute the mass and volume fraction of a chemical mixture. ALOHA and MARPLOT were also used to gather data on toxicity, thermal radiation, overpressure, and impacted zones. The quantity of chemicals emitted was calculated for three distinct leakage sizes (10 mm, 75 mm, and 160 mm). The findings showed that the plant with 331 bars at a ratio of 1:3 had the highest fatality rate of 16.07 %, which was caused by methanol leakage at night for a leakage size of 160 mm. This work has the potential to lower the number of deaths caused by methanol plants.

Utilising CO2 from manganese plant flue gas for methanol production: System design and optimisation

A potential measure to mitigate climate change and high energy consumption is the conversion of the abundant carbon dioxide (CO2) in industrial flue gas into value-added products. Herein, combined with the 300,000 tonnes of electrolytic manganese metal technical renovation project of Tianyuan Manganese Industry in Ningxia, the methanol production performed using 10,000 tonnes of CO2 annually is simulated. The hydrogen produced by alkaline hydro-electrolysis through solar and wind power generation is mixed with the CO2 purified in the manganese dioxide roasting workshop of the self-made manganese plant and fed into the methanol reactor with a Cu/Zn/Al/Zr catalyst. The methanol thus obtained is sold after separation and purification. The water at the bottom of the rectifying column is mixed with fresh water and circulated in the water electrolytic unit for hydrogen production. The design of the supporting photovoltaic (PV) power generation systems is simulated using TRNSYS18 software. Results show that the optimal reaction temperature, pressure and space velocity for methanol preparation using this system are 501 K, 50 bar and 5.9 m3/kgcat h, respectively. Simulation results indicate that the proposed methanol production process boasts a higher energy efficiency and process yield than the conventional process. Consequently, potential annual profits would increase by USD6.71 × 107 along with reduced greenhouse gas emissions. This study thus provides a novel approach for cogeneration of green methanol while reducing industrial waste gas emission.

Biomethanol production via electrolysis, oxy-fuel combustion, water-gas shift reaction, and LNG cold energy recovery

The hydrogen economy is of crucial importance in energy policies worldwide. Moreover, there are many benefits to producing biomethanol because it can be used in engines to achieve high efficiency, zero emission and lower risks of flammability. This research aims to evaluate a biomethanol and natural gas generation system that uses biomass gasification and high-temperature electrolysis. Thermal integration is applied between the steam generators of the gasifier and electrolyzer. The LNG regasification unit and an open Brayton cycle are responsible for power and natural gas production. The flue gas leaving the gas turbine leads to additional production of biomethanol. Oxygen management is applied between three different subsystems and there is a large amount of CO2 utilization as well. The results of energy analysis and thermodynamic modelling of an integrated system conducted in Aspen Plus indicate that the proposed cycle produces 16 644 ton/yr of natural gas, 1412 ton/yr of biomethanol, uses 3450 ton/yr of CO2, and has an efficiency of 81.96 %. Raising the methanol reactor temperature from 220 °C to 350 °C significantly enhances biomethanol capacity from 1015 ton/yr to 1930 ton/yr, leading to a 4 % increase in total energy efficiency.

High-performance addition reaction of methyl acrylate and methanol for the preparation of Methyl 3-methoxypropionate on NiO/MgO catalyst

In this study, Methyl 3-methoxypropionate (MMP) was formed from the addition reaction of methyl acrylate (MA) and methanol using MO/MgO (M = Ce, Co, Ni) catalysts, which were prepared by a direct-mixing method. The prepared catalyst NiO/MgO shows good catalytic activity than that of the CeO/MgO and CoO/MgO under the same conditions. The characterization and catalytic activity evaluation indicate that the NiO content of NiO/MgO has a significant effect on the catalytic activity of the addition reaction by changing the acid-base properties of the catalyst. The synergistic effect of acidic and basic sites contributes to the addition reaction. The optimal reaction temperature and pressure for NiO/MgO on this addition reaction is 200 ℃ and 2 MPa, respectively (over 90% selectivity to MMP). The cycle test indicates that the NiO/MgO catalyst is highly recyclable.

Differences Between Heterotrophic and Nitrate-dependent Iron-oxidizing Microbial Communities in Bioreactor Sediment Treating Mine Wastewater

Nitrate-dependent iron oxidation (NDFO) is a novel mechanism for microbial bioremediation of metal and metalloid contaminants. During NDFO, microbes catalyze a redox reaction wherein nitrate is reduced to nitrite and nitrogen gas while Fe(II) is oxidized to solid Fe(III) hydroxide minerals. Metalloid contaminants such as selenium and arsenic have a propensity for adsorption to iron minerals produced during NDFO; some contaminants may also be concurrently bioreduced. A number of bacterial isolates have been shown to be capable of NDFO (e.g., Kappler et al. (2005), Kiskira et al. (2017)), but little work has been done to date characterizing mixed microbial communities performing NDFO. Some autotrophic communities have been characterized, with high relative abundances for strains of Gallionellaceae in both a freshwater sediment enrichment culture and an activated sludge culture (Blöthe and Roden 2009, Tian et al. 2020). In mixotrophic activated sludge cultures, the concentration of Fe(II) amendment was found to significantly impact microbial community composition; these cultures were fed with methanol in addition to Fe(II), and the dominant community members were Methyloversatilis and other methylotrophic strains (Liu et al. 2018). The work presented here examines microbial communities performing NDFO in the context of remediation, and in particular how differences between NDFO and heterotrophic communities may influence remediation effectiveness. This research characterizes and compares microbial communities performing NDFO versus heterotrophic denitrification during removal of selenium and nickel from mining wastewater. Sediment and influent water from a subsurface bioreactor treating mining wastewater were used to construct batch bioreactors, which were amended with selenium and nickel as well as either Fe(II) or methanol to investigate contaminant removal and microbial community composition in NDFO versus heterotrophic microbial communities. Both Fe(II) and methanol reactors removed total aqueous selenium to below the quantification limit, but Fe(II) reactors removed it more rapidly, likely due to adsorption of selenite. For nickel, removal to below the detection limit was achieved with methanol amendment, while Fe(II) amendment resulted in 42-95% removal. This was likely due to precipitation of nickel sulfide during sulfate reduction in methanol-amended reactors. DNA from the batch bioreactors will be sequenced and the results analyzed for differences among communities. Permutational multivariate analysis of variance and non-metric multidimensional scaling will be used to determine significant correlations of community composition with experimental variables, selenium and nickel removal, and NDFO (Roberts 2023, Kruskal 1964). Indicator species analyses (De Cáceres et al. 2010) will be applied to identify taxa found significantly more often (i.e., at a higher relative abundance) in one group of microbial communities than in any other group. The indicator species analysis may reveal whether there are groups of denitrifiers that predominate in NDFO conditions vs. groups that predominate during heterotrophic denitrification. The results of these microbial community analyses, in combination with the geochemical analyses, will improve our understanding of microbial communities performing NDFO in remediation environments.

Cerium oxide boosted CoFe-N codoped carbon nanotubes with abundant oxygen-vacancies toward efficient oxygen reduction and methanol oxidation reaction

In this study, we designed a novel strategy that utilizes N-doped carbon nanotubes as the chemical bond supporter to stabilize ultrafine CoFe alloy and introduces secondary CeO2 active sites into the hybrid, resulting in the formation of CeO2/CoFe-NCNTs heterostructures with exceptional bifunctional electrocatalytic capabilities. To be specific, solution dispersion and high-temperature calcination methods were employed to create the CoFe-NCNTs active sites through the introduction of ethylenediamine into the network interstitials of Co-EDTA and Fe-EDTA. The CeO2/CoFe-NCNTs hybrid not only promotes oxygen absorption and conversion of intermediates, but also accelerates charge transfer capability, thus enhancing oxygen reduction reaction (ORR) performance, while simultaneously inducing boosted the methanol oxidation reaction (MOR) activity. Moreover, the well-dispersed CoFe nanoparticles within the hybrid hold significant potential for establishing metal-nitrogen bonds with the N-doped carbon nanotube network, resulting in efficient catalytic behavior driven by synergistic effects with CeO2 nanoparticles, which contributes to reactant activation. As expected, the resultant CeO2/CoFe-NCNTs-2 exhibits remarkable electrocatalytic performance, with a current density of 281.40 mA cm−2 at a scan rate of 200 mV s−1 and a low Tafel slope (71.3 mV dec−1) for MOR, as well as achieving excellent half-wave potential and onset potential values of 0.834 and 0.90 V (vs. RHE) for ORR. Additionally, it exhibits durable cycle stability for both MOR and ORR, retaining 92.8% and 96.4% of its initial current density during the I-t test, respectively. This work establishes a highly efficient bifunctional earth-abundant electrocatalysts for both anode and cathode reactions in methanol fuel cells.

Enlightening the performance-boosting effect of electroactivation approaches on the electrooxidation of methanol reaction in acidic media catalyzed by cobalt-tin bimetallic nanocatalysts

This research investigates the impact of electrochemical activation on cobalt-tin (Cox-Sn100-x) bimetallic nanocatalysts for the methanol oxidation reaction (MOR) in acidic conditions. Two electroactivation protocols, namely activation in a phosphate buffer (PB) solution and in-situ activation, using chronoamperometry, were developed. The electrochemical performance of the MOR electrocatalyst was evaluated through cyclic voltammetry analysis within a specific electrode potential range. Optimal activation conditions for the PB solution were achieved at a pH of 3.0 and an activation potential of −1.3 V (vs. Ag/AgCl), while the in-situ activation process showed the best results at an activation potential of −0.7 V (vs. Ag/AgCl). Both the in-situ and PB electroactivated Co65–Sn35 catalysts exhibited significant enhancements in MOR activity, with the in-situ activation resulting in a 10-fold increase and the PB activation leading to an 8.5-fold increase. The proposed mechanism for this substantial enhancement involves simultaneous hydrogen evolution and water electrolysis during the electroactivation treatments of the Co65–Sn35 electrocatalyst. In fact, the formation of OHads species during the electroactivation treatment could provide a fraction of OHads which was essential for the MOR. These findings might present opportunities for the engineering and design of bimetallic noble metal-free nanocatalysts for efficient utilization in high-performance acidic direct methanol fuel cells (DMFCs).

Multi-factor optimization of bio-methanol production through gasification process via statistical methodology coupled with genetic algorithm

This work innovatively explores the bio-methanol production process, conducts comprehensive analyses, develops statistical models, and optimizes operational conditions, contributing valuable insights to the field of sustainable energy production from biomass. Accordingly, bio-methanol production from biomass through gasification route was investigated and simulated using Aspen Plus software. The effects of operational parameters on energy duty of gasification reactor and the methanol production rate in syngas to methanol reactor were investigated. The parameters affecting the process performance including temperature, pressure, and steam/feed ratio were examined using the response surface methodology (RSM) by central composite design (CCD) technique. Analysis of variance (ANOVA) was performed, and two quadratic models were derived. The predicted R2 values of these models for methanol mass flowrate and energy duty were 0.9394 and 0.9363, respectively. The optimal operational conditions were identified using genetic algorithm (GA). The optimum values of temperature, pressure, and steam/feed ratio in gasification reactor were 900 °C, 4 bar, and 0.675, respectively. This condition leads to methanol mass flowrate and energy duty of 4.254 kg/s and 40736.355 kw, respectively. In addition, sensitivity analysis was performed on syngas to methanol reactor performance.

Optimization of an Industrial Methanol Reactor Using Aspen Plus Simulator and Design Expert

The chemical conversion of carbon dioxide into methanol has the potential to address two major sustainability issues: the economically viable replacement of fossil energy resources and the avoidance of greenhouse gas emissions. However, the chemical stability of carbon dioxide poses a difficult barrier to its conversion, necessitating extreme reaction conditions, resulting in increased energy input and, subsequently, elevated equipment, operation, and environmental costs. This, in turn, could potentially undermine its promising sustainability as a raw material for the chemical and energy industries. This research aims to optimise methanol production from a methanol reactor by using design of experiment (DOE) in Design Expert and Aspen Plus as a reactor simulator. The optimisation process involved eight parameters: five inlet molar flowrates (CO, CO2, H2O, H2, CH3OH) and three reactor conditions (inlet temperature, pressure, and temperature profile). The methanol production in Design Expert was optimised using the Box-Behnken method and a quadratic model. This study used the maximum range for each parameter as the actual industrial data and the minimum range to be 50% below it. The validated Aspen-Plus model was used for methanol production simulation. Response surface methodology (RSM) was used to determine the optimal parameters. This simulation required 120 samples. The optimal parameter values from the RSM were 142.2 kmol/hr of inlet CH3OH, 2250.91 kmol/hr of CO, 1398.3 kmol/hr of CO2, 15.6973 kmol/hr of H20, 19053.7 kmol/hr of H2, 497.883K of reactor inlet temperature, 81.9999 bar of reactor pressure, and 30K for reactor temperature profile with the actual methanol production of 2814.23 kmol/hr. The optimal values were simulated to test the accuracy of the predictive model, and the error was less than 5.2 percent. Overall, the inlet H2 molar flowrate was reduced in optimised conditions, reducing raw material usage and increasing output.

Tandem catalysts of different crystalline In2O3/sheet HZSM-5 zeolite for CO2 hydrogenation to aromatics

In tandem catalysts, not only good synergy between the two active components is required, but also the precise control of the spatial distribution between the two active components of metal oxides and zeolite is crucial for the migration and conversion of reaction intermediates in the direct conversion of CO2 to hydrocarbons. The correlation between the metal and the acidic site of zeolite has traditionally been simplified as “the closer, the better”. However, it should be noted that this principle only holds true for a portion of tandem catalysts. Therefore, this paper studied the effect of different crystalline In2O3 (cubic phase, hexagonal phase, and mixed cubic/hexagonal phase) and sheet HZSM-5 zeolite tandem catalysts on the activity of CO2 hydrogenation reaction under different spatial distribution. The generalized gradient approximation (GGA) of density functional theory (DFT) were used to simulate the adsorption energy of CO2 by oxygen vacancy on c-In2O3(111) and h-In2O3(104) planes, it was found that Ov1 on c-In2O3(111) and Ov4 on h-In2O3(104) had the strongest adsorption energy for CO2. In addition, it has been observed that the proximity of the two active components (e.g., during mortar mixing) results in decreased catalytic performance. This is due to the migration of metal In, which neutralizes the acid sites of zeolites and leads to inefficient conversion of methanol reaction intermediates to aromatics. As a result, CO2 conversion and aromatic selectivity are decreased.