Production of Ethylene From Ethanol Dehydration Over H3PO4-Modified Cerium Oxide Catalysts = Penghasilan Etilena Daripada Pendehidratan Etanol Dengan Mangkin Serium Oksida Terubahsuai H3PO4

Production of ethylene from ethanol dehydration was investigated over H3PO4 (10 wt.% to 30wt.%)-modified cerium oxide catalysts synthesized by wet impregnation technique. The prepared catalysts were characterized using scanning electron microscope (SEM), N2 adsorption-desorption method, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) for the physicochemical properties. The ethanol catalytic dehydration was carried out in a fixed-bed reactor at 673-773 K and at ethanol partial pressure of 33 kPa. The effects of phosphorus loading on catalyst and reaction temperatures were investigated in terms of catalytic activity towards product selectivity and yield. Overall, the selectivity and yield of ethylene increased with the temperature and phosphorus loading. The highest ethylene selectivity and yield were 99% and 65%, respectively, at 773 K and 33 kPa over the 30 wt.% H3PO4-modified cerium oxide

Aquivion® PFSA-based spray-freeze dried composite materials with SiO2 and TiO2 as hybrid catalysts for the gas phase dehydration of ethanol to ethylene in mild conditions

Aquivion PFSA resin, a perfluorinated ion-exchange polymer, has been used as a heterogeneous strong acid catalyst for a range of reactions; however, the activity of this material is limited due to the extremely low surface area of the polymer. In this paper we described the one-step synthesis of Aquivion® PFSA-based hybrid materials using heterocoagulation and spray-freeze-drying of sols containing the precursor of the active phases. The intimated encapsulation of different nano-oxides, such as TiO2 and SiO2 in the superacid resin matrix was easily obtained using this technique and compared with similar catalysts prepared by the impregnation conventional route. The approach led to the preparation of porous micro-granules characterised by a high homogeneity in the phase distribution and high surface area. The prepared materials were active and selective for the gas phase dehydration of ethanol to ethylene in mild conditions. The increase of the porosity improved the activity of the composites, compared to the pure Aquivion® PFSA, and allowed to reduce the amount of the superacid resin. Moreover, the type of encapsulated oxide, TiO2 or SiO2, modified the improved performance of the catalysts, having TiO2 the higher efficiency for ethanol conversion and selectivity in ethylene at very low temperature

Influence of Phosphoric Acid Modification on Catalytic Properties of γ-χ Al2O3 Catalysts for Dehydration of Ethanol to Diethyl Ether

In this present work, diethyl ether, which is currently served as promising alternative fuel for diesel engines, was produced via catalytic dehydration of ethanol over H3PO4-modified g-c Al2O3 catalysts. The impact of H3PO4 addition on catalytic performance and characteristics of catalysts was investigated. While catalytic dehydration of ethanol was performed in a fixed-bed microreactor at the temperature ranging from 200ºC to 400ºC under atmospheric pressure, catalyst characterization was conducted by inductively coupled plasma (ICP), X-ray diffraction (XRD), N2 physisorption, temperature-programmed desorption of ammonia (NH3-TPD) and thermogravimetric (TG) analysis. The results showed that although the H3PO4 addition tended to decrease surface area of catalyst resulting in the reduction of ethanol conversion, the Al2O3 containing 5 wt% of phosphorus (5P/Al2O3) was the most suitable catalyst for the catalytic dehydration of ethanol to diethyl ether since it exhibited the highest catalytic ability regarding diethyl ether yield and the quantity of coke formation as well as it had similar long-term stability to conventional Al2O3 catalyst. The NH3-TPD profiles of catalysts revealed that catalysts containing more weak acidity sites were preferred for dehydration of ethanol into diethyl ether and the adequate promotion of H3PO4 would lower the amount of medium surface acidity with increasing catalyst weak surface acidity. Nevertheless, when the excessive amount of H3PO4 was introduced, it caused the destruction of catalysts structure, which resulted in the catalyst incapability due to the decrease in active surface area and pore enlargement.  

Ethylene Production from Bioethanol Dehydration over Bimetallic Alkaline Earth Oxide-Alumina Catalyst

This research will be focusing on preliminary development studies on catalyst that can help increase the resistance of catalyst toward coke formation which mainly due to decomposition of carbon. Research found that alkaline earth metal oxide has the basic property that might be able to help increase catalyst’s resistance toward coke formation during the catalytic bioethanol dehydration process. In the research, two kinds of alkaline earth oxide metals are impregnated with nickel on the alumina, which are magnesium oxide and calcium oxide. A preliminary characterization on the catalysts been carried out with Sieve Shaker, FTIR, FESEM, EDX, and TGA. The prepared catalysts have been tested with catalytic dehydration process to find out its effectiveness in converting ethanol to ethylene and the spent catalysts were tested on total carbon content analysis using CHNS. Results show that CAT5 is the most effective catalyst with ethylene conversion of 65.36% and total carbon content or 1.323wt%

The impact of preparation route on the performance of silver dodecatungstophosphate/β zeolite catalysts in the ethylene production

Heteropolyacids and their salts comprise catalytic centers for the production of ethylene, one of the most important constituents in the chemical industry. The paper emphasizes different synthesis routes of hybrid materials consisting of dodecatungstophosphoric acid silver salt (AgPW) and β zeolite—stepwise wet impregnation, silver-exchange in β zeolite, and dry mixing of precursors. Composite preparation procedures induced minor effects on the weak acid sites, while strong acid sites were increased significantly. β/AgPW composites prepared by two-steps wet impregnation and ion-exchange procedures have strong acid sites content and total acidity higher in comparison to the pure AgPW salt and β zeolite. This is a result of precursors synergetic effect—cumulative strong acidic sites are generated in the presence of well-dispersed Keggin ions on the zeolite network. Composite samples with a higher content of strong acid centers exhibit higher conversion in the ethanol dehydration reaction, i.e., the ion-exchanged βAgPW sample has attained a conversion over 81%, while the wet-impregnated sample has a significant 86%. The distribution and presence of AgPW active phase are found to be crucial for both stable conversion and high selectivity results in ethylene production from ethanol, which is regarded as one of the most significant processes in environmental and sustainable industrial chemistry. Graphic abstract: [Figure not available: see fulltext.

Review of Established and Emergent Methods for the Production of C4 Olefins

Current production of C4 olefins is dominated by naphtha cracking and butane dehydrogenation, but significant research interest is developing in alternate feedstocks due to an abundance of inexpensive natural gas and bioethanol. The current C4 olefin production methods are costly, make use of already-depleted petroleum resources, and are often hazardous to workers, which forms the impetus for investigation into alternative methods and assessment of their viability as a future means of olefin production. Methods of natural gas conversion to higher order hydrocarbons are discussed, including Fischer-Tropsch synthesis and oxidative methane coupling, each of which could form the first step in a hypothetical natural gas-to-olefins process. The historically common Lebedev, Ostromislensky, and Fripiat methods for 1,3-butadiene production from ethanol feedstocks are described and analyzed, although these processes largely fell out of favor in the decades following World War II in favor of sources derived from naphtha cracking. Another well-known process involving C4 olefins, olefin metathesis, is considered, although the reaction is more commonly used to produce propylene. Biological processes are discussed as well, including the well-known production of bioethanol from sugars and starches, and also more novel processes such as an effort to use genetically engineered microorganisms to produce specific intermediates for olefin production, and in some cases, direct olefin production from these organisms. Finally, several promising schemes are identified and analyzed, in an attempt to compare their potential viability in key areas. Two of the most promising emergent methods today identified in this review are the bio-catalyzed production of 1,4-butanediol and/or butadiene using E. coli, and a microwave radiation-assisted scheme in which methane is selectively dimerized twice to form 1-butene

Bio-ethylene Production: from Reaction Kinetics to Plant Scale

Ethylene production from renewable bio-ethanol has been recently proposed as sustainable alternative to fossil sources. The possibility to exploit diluted bioethanol as less expensive feedstock was studied both experimentally, using different catalysts at lab-level, and through preliminary process design. In this work, a full-scale plant simulation is presented, built on a detailed reaction kinetics. Rate equations for the primary and side reactions are revised and implemented with a process simulation package, using a range of thermodynamic methods as best suited to the different process stages. The catalyst loading within the reactor can be effectively distributed according to the underlying kinetic, and the overall plant layout let foresee the best routes for the material recycles. The detailed reaction modeling and the choice of the thermodynamic models are essential to obtain reliable predictions. Setting a target yield of 105 t/year of polymer-grade ethylene, the reactive section must be fed with 76 t/h of diluted ethanol and operated at 400 \ub0C. 85% of the fed carbon mass is found as ethylene, 12% remains as ethanol and a 2% as longer olefins. Considering also the recycle of ethanol the carbon conversion and recovery increases to the value of 97.6%. The global ethylene recovery is 90.7%: most of the loss takes place in the last stage due to the non-condensable purification and to the adopted strategy of having low reflux ratio \u2013 and then a closed cryogenic balance \u2013 in the last purification column. Full heat integration of the process with upstream bioethanol production and purification sections allows process intensification and consistent energy savings. This newly designed process sets the sustainable ethylene production on a detailed and reassessed computational basis and has been assessed as for Capital and Operational Expenditures and Total Investment costs

Potential Routes for Thermochemical Biorefineries

This critical review focuses on potential routes for the multi-production of chemicals and fuels in the framework of thermochemical biorefineries. The up-to-date research and development in this field has been limited to BTL/G (biomass-to-liquids/gases) studies, where biomass-derived synthesis gas (syngas) is converted into a single product with/without the co-production of electricity and heat. Simultaneously, the interest on biorefineries is growing but mostly refers to the biochemical processing of biomass. However, thermochemical biorefineries (multi-product plants using thermo-chemical processing of biomass) are still the subject of few studies. This scarcity of studies could be attributed to the limitations of current designs of BTL/G for multi-production and the limited number of considered routes for syngas conversion. The use of a platform chemical (an intermediate) brings new opportunities to the design of process concepts, since unlike BTL/G processes they are not restricted to the conversion of syngas in a single-reaction system. Most of the routes presented here are based on old-fashioned and new routes for the processing of coal- and natural-gas-derived syngas, but they have been re-thought for the use of biomass and the multi-production plants (thermochemical biorefinery). The considered platform chemicals are methanol, DME, and ethanol, which are the common products from syngas in BTL/G studies. Important keys are given for the integration of reviewed routes into the design of thermochemical biorefineries, in particular for the selection of the mix of co-products, as well as for the sustainability (co-feeding, CO2 capture, and negative emissions).Ministerio de Educación FPU Program (AP2010-0119)Ministerio de Economía y Competitividad ENE2012-3159