One-step Synthesis Of Dimethyl Ether Research Articles

Perspective on CO2 Hydrogenation for Dimethyl Ether Economy

The CO2 hydrogenation to dimethyl ether (DME) is a potentially promising process for efficiently utilizing CO2 as a renewable and cheap carbon resource. Currently, the one-step heterogeneous catalytic conversion of CO2 to value-added chemicals exhibits higher efficiency than photocatalytic or electrocatalytic routes. However, typical catalysts for the one-step CO2 hydrogenation to DME still suffer from the deficient space–time yield and stability in industrial demonstrations/applications. In this perspective, the recent development of the one-step CO2 hydrogenation to DME is focused on different catalytic systems by examining the reported experimental results and the reaction mechanism including the catalytic nature of active sites, activation modes and of CO2 molecules under relevant conditions; surface intermediates are comparatively analyzed and discussed. In addition to the more traditional Cu-based, Pd-based, and oxide-derived bifunctional catalysts, a further emphasis is given to the characteristics of the recently emerged In2O3-based bifunctional catalysts for the one-step conversion of CO2 to DME. Moreover, GaN itself, as a bifunctional catalyst, shows over 90% DME selectivity and a reasonably high activity for one-step CO2 hydrogenation, and the direct hydrogenation of CO2 via the unique non-methanol intermediate mechanism is highlighted as an important illustration for exploring new catalytic systems. With these analyses and current understandings, the research directions in the aspects of catalysis and DME economy are suggested for the further development of one-step DME synthesis from CO2 hydrogenation.

Biogas to advanced biofuels: Techno-economic analysis of one-step dimethyl ether synthesis

Bio-dimethyl ether (bio-DME) is a promising advanced biofuel for the disposal of conventional diesel fuel, which is one of the most relevant sources of particulate matter and nitrogen oxides in urban centres and is completely banned from some European cities. DME is produced in two ways: dehydration of methanol produced from syngas (indirect or two-step process) and direct synthesis from syngas (direct or one-step process). This work aims at studying, optimizing and economically and environmentally assessing a novel conceptual design to convert biogas into bio-DME. Contrarily to traditional DME processes, the synthesis from biogas strongly benefits from milder conditions due to the smaller plant size, rural context, and biological feedstock fluctuations, motivating an ex-novo techno-economic feasibility study and sensitivity analysis performed in Aspen HYSYS V11 suite. The proposed process layout allows converting 1045 kg/h of silomais-based biogas (67%v/v CH4 content) into 516 kg/h of bio-DME at ASTM D7901-14 standard specification for fuel purposes. Sensitivity analysis identifies reactor temperatures as important process variables and defines three key performance indicators as: (i) global yield of the process; (ii) DME versus methanol selectivity; (iii) and the thermal load for the downstream section. The last one is computed as the sum of reboiler and condenser duties normalized with respect to the DME massive flowrate, and the study provides 1.05 kWh/kgDME as downstream section global specific duty. The process provides an innovative way to face the EU RED II challenge due to a 49.4 wt.% bio-DME yield and also thanks to a competitive 9.5 yr of payback period.

One-step synthesis of dimethyl ether from biomass-derived syngas on CuO-ZnO-Al2O3/HZSM-5 hybrid catalyst: Combination method, synergistic effect, water-gas shift reaction and catalytic performance

The hybrid systems of CuO-ZnO-Al2O3/HZSM-5 for the one-step synthesis of DME from biomass-derived syngas were prepared by four different combination methods (granule-mixing, powder-mixing, physical coating and dual-bed fixing) and characterized by N2 adsorption, XRD, N2O titration, H2-TPR, NH3-TPD and TG techniques. The influences of combination method on the physicochemical properties and catalytic performances of hybrid catalyst were investigated, and the relationship among the combination method, the synergistic effect and the WGS reaction was discussed based on the composition features of the biomass-derived syngas (CO2-rich and H2-deficient). A maximum of CO conversion and DME yield was obtained over the hybrid catalyst prepared by granule-mixing method. There is a synergistic effect, which remarkably promotes the formation of DME, between the methanol synthesis and the methanol dehydration over the hybrid catalysts except for the hybrid system configured using the dual-bed fixing method. The WGS reaction, playing a pivotal role in the direct DME synthesis because of the in-situ produced hydrogen, relates to the combination method closely. An interaction between the two catalyst components arising in the combination process affects the properties of active sites and further the catalytic performances. The deactivation of the hybrid catalyst is ascribed mainly to the increase in the particle size of Cu in CuO-ZnO-Al2O3.

Synthesis of Syngas into Dimethyl Ether Using Cu-Zn-Al/-Alumina Bifunctional Catalyst as an Environmentally Friendly Fuel for Substituting Liquified Petroleum Gas

In order to meet the need for Liquified Petroleum Gas in Indonesia, which is currently around seventy percent of which is still imported, it is necessary to find a replacement. One of the efforts to replace the Liquified Petroleum Gas is by utilizing dimethyl ether which can be produced from coal as raw material. Coal can be catalytically converted to syngas and then syngas can be catalytically converted to dimethyl ether via a direct two-step or one-step route. This paper will discuss the one-step synthesis of dimethyl ether from syngas using Cu-Zn-Al/g-Alumina as a bifunctional catalyst. The syngas used consists of carbon monoxide and hydrogen with a mole ratio of 1:2. The conversion reaction was carried out in a fixed-bed reactor at the pressure of 40 bar, the temperature of 240-300 <sup>0</sup>C, and the space velocity of 29.3-32.7 mL/g catalyst/minute. The highest conversion of CO that can be achieved is 90.08 % at a temperature of 300 <sup>o</sup>C and the space velocity of 29.3 mL/g catalyst/minute. The synthesis product was analyzed using GC. The dimethyl ether is an environmentally friendly fuel and non-toxic compound that does not destroy ozone, does not contain sulfur, and has a calorific value of about 30.5 MJ/kg which is lower than 50.56 MJ/kg

Life Cycle Assessment for Full Chain CCU Demonstration in the Align-CCUS Project –Dimethyl Ether and Polyoxymethylen Dimethyl Ethers Production from CO2 and its Usages in the Mobility and Electricity Sectors

As part of three years of research and development in the European ALIGN-CCUS project, a CCU demonstration plant was erected at the lignite-fired block K of the RWE power plant at Niederaussem, Germany. It was the aim to demonstrate the full chain of CCU - beginning with the capture of CO2 from the power plant flue gas stream, via the one-step synthesis of dimethyl ether (DME) through to its usage for electricity generation in a peak power diesel engine generator. A secondary target was the synthesis of polyoxymethylen dimethyl ethers (OMEs) and their use in the mobility sector. A thorough Life Cycle Inventory was collected based on real process data for the first time, supported by process modelling with AspenPlus. This includes the inventory for construction and operation of all elements of the demonstrator chain: the power plant with its monoethanolamine (MEA)-based post-combustion capture facility, the newly developed synthesis unit based on a one-step reactor using a bifunctional catalyst (up to 50 kg DME per day) and the reconversion of the produced DME into electricity by an adapted diesel power generator (60-80 litre per hour DME consumption, output 240 kWel). Additionally to the DME-route, the synthesis and usage of OME3-5 as a fuel in an adapted 2 l diesel motor for mobility application were part of the investigation. The extensive inventory enabled a Life Cycle Assessment (LCA) according to ISO standards showing results for both applications. Benchmarking technologies like diesel- and e-mobility and gas turbines for peak power supply enable a comparative analysis identifying advantages and disadvantages of the CCU route. A sensitivity analysis is used to identify weak points along the routes together with future development targets and potentials. To investigate a broad array of results, several varying scenarios, especially regarding energy supply were considered. The use of renewable electricity sources for electrolytic hydrogen production, but also for other processes of the CCU chain was investigated. A range of different impact categories were considered: Global Warming Potential (GWP), Particulate Matter Formation Potential (PM), Fossil Depletion Potential (FDP), Photochemical Ozone Creation Potential (POCP) and Terrestrial Acidification Potential (AP). The results show that the investigated CCU technology routes are highly emission-intensive when using the current German electricity mix: the reuse of CO2 and the reduction of fossil fuel consumption that goes along with it, is outweighed by the energy-intensive nature of the synthesis processes. Using renewable energy sources can drastically reduce GHG emissions, especially to a point where the implementation of a mostly renewable energy supply for the process chain offers a viable mitigation option compared to the investigated benchmark technologies. Findings regarding sensitive LCI data, development targets and technological potentials are discussed in the results.

Probing Hydrophobization of a Cu/ZnO Catalyst for Suppression of Water–Gas Shift Reaction in Syngas Conversion

Due to the complexity of the structure and surface property of metal oxide catalysts, hydrophobization of metal oxide catalysts is a great challenge. The hydrophobization strategy and effects of hydrophobization on the surface property and catalytic performance of metal oxide catalysts deserve rigorous investigations. Herein, we adopt stearic acid to functionalize the surface of a Cu/ZnO catalyst by bridging stearic acid molecules with the Cu/ZnO catalyst surface. After functionalization, the hydrophobicity of the Cu/ZnO catalyst is greatly reinforced, while its structure and catalytic performance remain nearly unchanged. The hydrophobic Cu/ZnO catalyst exhibits a very positive inhibitory effect on the unfavorable water–gas shift reaction (WGSR) in one-step synthesis of dimethyl ether (DME) from syngas (CO + H2), while the catalytic activity of the hydrophobic Cu/ZnO catalyst for methanol synthesis is not affected. Lower CO2 selectivity and higher DME selectivity over the hydrophobic Cu/ZnO-4 catalyst, better than those of untreated catalyst, are obtained facilely. The promoted catalytic performance of the hydrophobic Cu/ZnO catalyst demonstrates that the surface hydrophobicity of heterogeneous catalysts is worthy of more attention for enriching their catalytic roles.

Highly Conductive Structured Catalytic Reactors for One-Step Synthesis of Dimethyl Ether.

Several structured catalytic reactors for the direct synthesis of the DME reaction are compared with regard to catalyst hold-up, thermal conductivity, and volumetric productivity. Adherent and homogeneous catalyst layers were obtained by washcoating independent of the substrates’ shape and alloy. Moreover, the substrate nature (FeCrAl, brass, or aluminum) and shape (parallel cell monoliths and open foams) do not modify in great extent the CO conversion values and selectivity to the different compounds. This is reasonable since the catalytic phases are the same in all cases and the existence of mass and heat-transfer limitations was negligible in the experimental conditions studied. Structuring by washcoating exhibits less catalyst inventory per reactor volume than a packed-bed monolith. However, completely packing a monolith with powder catalyst produced a decrease in the CO conversion of around 25% with respect to the coated monolith. Moreover, by means of using the obtained highest catalyst hold-up by washcoating (0.33 gcat/cm3) in a brass monolith and by increasing the reaction temperature, the temperature profiles are only slightly affected. This allows to work in an almost isothermal reactor with a volumetric productivity up to 0.20 LDME/h·cm3 at 573 K.

Kinetics of the direct DME synthesis from CO2 rich syngas under variation of the CZA-to-γ-Al2O3 ratio of a mixed catalyst bed.

The one-step synthesis of dimethyl ether over mechanical mixtures of Cu/ZnO/Al2O3 (CZA) and γ-Al2O3 was studied in a wide range of process conditions. Experiments were performed at an industrially relevant pressure of 50 bar varying the carbon oxide ratio in the feed (CO2 in COx from 20 to 80%), temperature (503–533 K), space-time (240–400 kgcat s mgas−3), and the CZA-to-γ-Al2O3 weight ratio (from 1 to 5). Factors favoring the DME production in the investigated range of conditions are an elevated temperature, a low CO2 content in the feed, and a CZA-to-γ-Al2O3 weight ratio of 2. A lumped kinetic model was parameterized to fit the experimental data, resulting in one of the predictive models with the broadest range of validity in the open literature for the CZA/γ-Al2O3 system.

Strategies for the Intensification of CO2 Valorization in the One-Step Dimethyl Ether Synthesis Process

The intensification of CO2 valorization has been theoretically studied in the direct synthesis of dimethyl ether (DME) carried out in a packed-bed reactor by means of two strategies pursuing the at...

Improved stability of Pd/HZSM-5 bifunctional catalysts by the addition of promoters (CeO 2 , CaO) for the One-step synthesis of dimethyl ether from Sulfur-containing CO 2 hydrogenation

Abstract Pd/HZSM-5 bifunctional catalysts modified with CeO2 and CaO promotors were prepared by impregnation. The combined promotor effects on the activity and stability of Pd/HZSM-5 bifunctional catalysts for one-step-synthesis of dimethyl ether (DME) from the sulfur-containing CO2 hydrogenation at 250 °C and GHSV of 1600 h−1 under three megapascals were investigated. The physical and chemical characteristics, activity, sulfur resistance stability and carbon deposition of the bifunctional catalysts were analyzed by XRD, N2 adsorption, FT-IR, CO2-TPD, NH3-TPD, H2-TPR and TPO-TG. Correlations were identified between the quantity of the combined promotors and the moderate acidity level of the surface and active Pd dispersion of the bifunctional catalyst. The optimum stability of Pd/HZSM-5 bifunctional catalyst occurred with the addition of 3 wt% CeO2 and 1 wt% CaO, and the CO2 conversion and DME selectivity remained higher than 19% and 67% after a 20 h reaction. The rates of carbon-deposition, the moderate-acidity-loss and the Pd-site-loss were reduced by 61.1%, 38.79% and 22.17%, respectively, compared with promotor-free Pd/HZSM-5.

Design and Synthesis of Powerful Capsule Catalysts Aimed at Applications in C1 Chemistry and Biomass Conversion.

Tandem catalytic reaction is a promising strategy to improve the utilization efficiency of energy and resources. The conventional hybrid catalysts cannot readily realize the precisely controlled synthesis of target products due to the unrestricted, open reaction environment. Assembling the hybrid catalyst with multiple active sites into core-shell structured capsule catalyst is one of the most effective ways to enhance the selectivity of desired products during a tandem catalysis process, because the core-shell structure offers a space-confined reaction field and synergistic effect. This review describes our recent progresses on the design and synthesis of core-shell structured zeolite capsule catalysts developed for C1 chemistry and biomass conversion. The various synthesis methods for constructing the well-defined zeolite capsule catalysts are described in detail. The applications of the capsule catalysts in catalysis, including the middle isoparaffins synthesis from syngas, one-step synthesis of dimethyl ether, and liquid-phase tandem reaction of glycerol conversion, are discussed, respectively. Our perspectives regarding the challenges and opportunities for future research in the field are also provided.

Catalysis in the dispersed phase: Slurry technology in the synthesis of dimethyl ether (Review)

The world market of dimethyl ether (DME) is rapidly gaining in strength. The review addresses prospects for using the slurry technology in the large-scale world production of DME. The literature and patent data pertaining to the manufacture of dimethyl ether in slurry reactors using finely divided heterogeneous catalysts suspended in inert liquids are generalized. Variants of the slurry technology used in the one-step DME synthesis from syngas and in the two-step DME synthesis (at the stage of dimethyl ether manufacturing via methanol dehydration) are considered. Advantages of the slurry technology over the conventional gas-phase methods of DME production are highlighted.

Catalyst Deactivation During One-Step Dimethyl Ether Synthesis from Synthesis Gas

Catalysts for direct synthesis of dimethyl ether (DME) from synthesis gas should essentially contain two functions, i.e., methanol synthesis and methanol dehydration. In the present work, the deactivation of both functions of hybrid catalysts during direct DME synthesis under industrially relevant conditions has been investigated with special focus on the influence of each reaction step on the deactivation of the catalyst function corresponding to the other step. A physical mixture of a Cu–Zn-based methanol synthesis catalyst and a ZSM-5 methanol dehydration catalyst was used. The metallic catalyst appears to deactivate due to Cu sintering, with no apparent effect from the methanol dehydration step under the conditions applied. The acid catalyst deactivates due to accumulation of hydrocarbon species formed in its pores. Synthesis gas composition, i.e., $$\text{{H}}_{2}$$ /CO ratio and $$\text{{CO}}_{2}$$ -content (which directly affects partial pressure of water), seems to influence the zeolite deactivation.

Modified Two-Step Dimethyl Ether (DME) Synthesis Simulation from Indonesian Brown Coal

A theoretical study was conducted to investigate the performance of dimethyl ether (DME) synthesis from coal. This paper presents a model for two-step DME synthesis from brown coal represented by the following processes: drying, gasification, water-gas reaction, acid gas removal, and DME synthesis reactions. The results of the simulation suggest that a feedstock ratio of coal : oxygen : steam of 1 : 0.13 : 0.821 produces the highest DME concentration. The water-gas reactor simulation at a temperature of 400°C and a pressure of 20 bar gave the ratio of H 2 /CO closest to 2, the optimal value for two-step DME synthesis. As for the DME synthesis reactor simulation, high pressure and low temperature promote a high DME concentration. It is predicted that a temperature of 300°C and a pressure of 140 bar are the optimum conditions for the DME synthesis reaction. This study also showed that the DME concentration produced by the two-step route is higher than that produced by one-step DME synthesis, implying that further improvement and research are needed to apply two-step DME synthesis to production of this liquid fuel.

Facile preparation of highly efficient CuO-ZnO-ZrO2/HZSM-5 bifunctional catalyst for one-step CO2 hydrogenation to dimethyl ether: Influence of calcination temperature

CuO-ZnO-ZrO2/HZSM-5 bifunctional catalysts were prepared by a facile route of solid-state reaction and tested for one-step synthesis of dimethyl ether (DME) from CO2 hydrogenation. The effects of calcination temperature (300–600°C) on the physicochemical and catalytic properties of the bifunctional catalysts were investigated by XRD, N2 adsorption, XPS, N2O chemisorption, SEM, H2-TPR, NH3-TPD, and CO2-TPD techniques. The results show that both the CO2 conversion and DME selectivity of the bifunctional catalysts decrease with the increase in calcination temperature, which can mainly be attributed to the decrease of metallic copper surface area (SCu), adsorption capacity of CO2, specific surface area, and reducibility of CuO.

One-step synthesis of dimethyl ether from syngas on ordered mesoporous copper incorporated alumina

Ordered mesoporous copper incorporated Al2O3 (Cu/Al2O3) with high Cu dispersion were prepared by a facile solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and urea as fuel. It is a facile and green route to synthesize catalysts for dimethyl ether directly from syngas. Cu/Al2O3 catalysts were characterized by XRD, N2 adsorption–desorption, SEM-EDS, and H2-TPR. The results indicate that the catalysts obtain an ordered mesoporous structure and copper is homogenously dispersed. The mesoporous Cu/Al2O3 catalysts were utilized as bifunctional catalysts in syngas to dimethyl ether reaction (STD). The copper content affects the catalytic performance in STD reaction. The CO conversion and DME selectivity of Cu/Al2O3 with 15% copper molar ratio achieve 52.9% and 66.1%, respectively. Moreover, the mesoporous Cu/Al2O3 catalysts show excellent stability in STD reaction.

Dimethyl ether production from CO2 rich feedstocks in a one-step process: Thermodynamic evaluation and reactor simulation

The dimethyl ether (DME) direct production from CO2-rich feedstock has been evaluated from thermodynamic and fixed bed reactor simulation perspectives, in order to evaluate the potentialities of using CO2 as reagent in one-step DME synthesis. The thermodynamic model has been applied to perform a detailed sensitive analysis of DME synthesis process at temperature within the range 200–275°C, pressures of 20–70bar and inlet composition of H2/CO=1–3 and CO2/CO=0–2.5. The results show a stringent thermodynamics threshold in DME yield (DME yield<30%), when the CO2/CO ratio is greater than 2 in the fed to the synthesis reactor. The results have been confirmed by the kinetic mathematical model and reactor simulation, which includes chemical reactions, heat transfer and pressure drop along the fixed bed reactor. The performed simulations point out the role of cooling fluid temperature and reactor pressure. Furthermore, the kinetic modeling, in agreement with the thermodynamic approach, evidences the negative effect of water formed during CO2 conversion and further steps. The proposed thermodynamic and kinetic insight states that water removal during CO2 conversion, for example by hydrophilic membrane, is a mandatory element to enable industrial production of DME in the framework of CO2 valorization.

Activity and Deactivation of ZSM–5 Catalysts in the Dimethyl Ether Synthesis from CO and H&lt;sub&gt;2&lt;/sub&gt; and Methanol Dehydration

The increasing demand for producing dimethyl ether from synthesis gas explains the renewed interest in studying the activity and stability of catalysts. In the present work, resource catalytic testing of ZSM-5 zeolites was carried out in the one-step synthesis of dimethyl ether from synthesis gas for 120 hours. Formation of condensation products was observed on zeolite surface after catalytic tests which leads to lower catalytic activity of samples. Condensation products were investigated by thermal analysis in an oxidizing atmosphere. Textural characteristics of zeolites before and after reaction were investigated. It was shown that methanol significantly contribute to formation of condensation products on the catalyst surface in the process of dimethyl ether production.

Influence of Compound Additive CeO2-MxOy on Catalytic Performace of Pd/γ-Al2O3 Catalyst for One-step Synthesis of Dimethylether

A series of Pd/γ-Al2O3 catalysts with different types of compound additives were prepared by impregnation under microwave calcination; the physicochemical properties and catalytic performance of catalysts for one-step synthesis of dimethylether from sulfur-containing syngas were investigated. The results show that the catalysts added CeO2-ZrO2 showed much better catalytic performance and sulfur tolerance than those added CeO2-ZnO or CeO2-CaO in terms of CO conversion, methanol, and dimethylether selectivities and time space yield of dimethylether, which are closely related to higher pore volume and Pd dispersity, moderate CO adsorption, and moderate surface acidity of the catalyst. The optimum compound additive content was determined to be 2%CeO2-1%ZrO2. Under such optimum conditions, CO conversion, dimethylether selectivity, and time space yield of dimethylether are 63.2%, 68.5%, and 30.92 mmol·(ml·h)−1, respectively.

The effect of preparation method of the Cu–La2O3–ZrO2/γ-Al2O3 hybrid catalysts on one-step synthesis of dimethyl ether from syngas

Cu–La2O3–ZrO2/γ-Al2O3 hybrid catalysts were prepared by four different preparation methods. The catalysts were characterized by N2 adsorption and desorption, N2O adsorption, X-ray diffraction (XRD), temperature programmed reduction (H2-TPR), temperature programmed desorption (NH3–TPD) and Fourier transform infrared (FTIR), followed by the evaluation for the one-step synthesis of dimethyl ether from syngas. The hybrid catalyst prepared by mixing freshly obtained precursors of both components possessed the highest CO conversion (73%) and DME yield (58%). It was revealed that the superior catalytic performance was not only ascribed to the amount of highly dispersed copper species with smaller particle size, which was benefit for the CO adsorption linearly, but also to the amount of acidic sites with medium strength.