Propylene Production Research Articles

Optimisation of Propane Production from Hydrothermal Decarboxylation of Butyric Acid Using Pt/C Catalyst: Influence of Gaseous Reaction Atmospheres

The displacement and eventual replacement of fossil-derived fuel gases with biomass-derived alternatives can help the energy sector to achieve net zero by 2050. Decarboxylation of butyric acid, which can be obtained from biomass, can produce high yields of propane, a component of liquefied petroleum gases. The use of different gaseous reaction atmospheres of nitrogen, hydrogen, and compressed air during the catalytic hydrothermal conversion of butyric acid to propane have been investigated in a batch reactor within a temperature range of 200–350 °C. The experimental results were statistically evaluated to find the optimum conditions to produce propane via decarboxylation while minimizing other potential side reactions. The results revealed that nitrogen gas was the most appropriate atmosphere to control propane production under the test conditions between 250 °C and 300 °C, during which the highest hydrocarbon selectivity for propane of up to 97% was achieved. Below this temperature range, butyric acid conversion remained low under the three reaction atmospheres. Above 300 °C, competing reactions became more significant. Under compressed air atmosphere, oxidation to CO2 became dominant, and under nitrogen, thermal cracking of propane became significant, producing both ethane and methane as side products. Interestingly, under a hydrogen atmosphere, hydrogenolytic cracking propane became dominant, leading to multiple C–C bond cleavages to produce methane as the main side product at 350 °C.

Sensitivity Analysis and Multi‐Objective Optimization of Oxidative Dehydrogenation of Propane in a Fixed‐bed Reactor over Vanadium/Graphene for Propylene Production

AbstractOxidative dehydrogenation of light alkanes is an attractive route for the production of olefins. This method does not need much energy, while common processes such as propane dehydrogenation and cracking require external energy resources and cause rapid catalyst deactivation. In this research, an isothermal one‐dimensional model of a fixed‐bed reactor was considered for oxidative dehydrogenation of propane over a V2O5/graphene catalyst. Operational parameter sensitivity analysis showed that high temperature (450–500 °C), high pressure (7–8 atm), a moderate molar propane to air feed ratio (about 0.7), and a low feed flow rate enhanced the propane conversion and propylene productivity. However, for the production of propylene as desirable product, low temperature, low pressure, a high molar ratio, and a high feed flow rate are preferred. Thus, to determine the exact interval of operational parameter values, a multi‐objective optimization was performed for the yields of propylene and COx, revealing a maximum propylene yield of ∼40 %. For safety reasons, a feed molar ratio of propane to air of > 0.6 was preferred, which is not in the flammable region.

Local Environment Determined Reactant Adsorption Configuration for Enhanced Electrocatalytic Acetone Hydrogenation to Propane

AbstractWe demonstrate a widely applicable method to alter the adsorption configuration of multi‐carbon containing reactants by no catalyst engineering but simply adjusting the local reaction environment of the catalyst surface. Using electrocatalytic acetone to propane hydrogenation (APH) as a model reaction and common commercial Pt/Pt‐based materials as catalysts, we found local H+ concentration can significantly influence the adsorption mode of acetone reactant, for example, in vertical or flat mode, and target product selectivity. Electrocatalytic measurement combined with in situ spectroscopic characterizations reveals that the vertically adsorbed acetone is favorable for propane production while the flatly adsorbed mode suppresses the reaction. DFT calculations indicate that the H coverage on catalyst surface plays a decisive role in the adsorption configuration of acetone. The increased local acidity can facilitate the adsorption configuration of acetone from flat to vertical mode and suppress the competing hydrogen evaluation reaction, which consequently enhances the APH selectivity.

Local Environment Determined Reactant Adsorption Configuration for Enhanced Electrocatalytic Acetone Hydrogenation to Propane

AbstractWe demonstrate a widely applicable method to alter the adsorption configuration of multi‐carbon containing reactants by no catalyst engineering but simply adjusting the local reaction environment of the catalyst surface. Using electrocatalytic acetone to propane hydrogenation (APH) as a model reaction and common commercial Pt/Pt‐based materials as catalysts, we found local H+ concentration can significantly influence the adsorption mode of acetone reactant, for example, in vertical or flat mode, and target product selectivity. Electrocatalytic measurement combined with in situ spectroscopic characterizations reveals that the vertically adsorbed acetone is favorable for propane production while the flatly adsorbed mode suppresses the reaction. DFT calculations indicate that the H coverage on catalyst surface plays a decisive role in the adsorption configuration of acetone. The increased local acidity can facilitate the adsorption configuration of acetone from flat to vertical mode and suppress the competing hydrogen evaluation reaction, which consequently enhances the APH selectivity.

Thermodynamics Insights into the Selective Hydrogenation of Alkynes in C2 and C3 Streams

Selective hydrogenation of alkynes in C2 and C3 streams from steam cracking of naphtha is significant for the production of polymer-grade ethylene and propylene. Herein, a comprehensive thermodynam...

Oxidative Dehydrogenation of Propane over Vanadium Catalyst Supported on Alkali-Modifiedx-Al2O3

The propane oxidative dehydrogenation (ODH) reaction has been considered as an alternative method for propene production owing to its exothermic nature, which renders it environmentally friendly. The use of alkaline promoters for supported V catalysts can increase propene selectivity and partially inhibit the formation of CO and CO2. Our goal was to evaluate the promoting effect of K and Na and the support effect using gibbsite as precursor for the propane ODH reaction. Catalysts were prepared via co-impregnation of V and alkali metals on a previously prepared alumina support and were characterized using N2 adsorption-desorption, X-ray diffraction, temperature-programmed reduction, and isopropanol decomposition tests to evaluate their acid-base properties. The activity of the synthesized catalysts for the propane ODH reaction was evaluated at the O2:C3H8:He molar ratios of 5:2:4, 6:1:4, and 4:3:4. The addition of alkali metals to the V catalysts increased propane conversion and propene selectivity; moreover, both parameters increased with increasing molar fraction of O2 in the reactants. K doping increased the propene selectivity of the doped catalysts, because it inhibited a large fraction of catalytic surface acidic sites. A high molar fraction of O2 in the reactants facilitated the regeneration of the catalyst, whereas a high reoxidation rate improved catalytic activity and propene selectivity.

Fine Tuning the Morphology of Spinel as Ultra‐Stable Catalyst Support in Propane Dehydrogenation

AbstractRecently, the propane dehydrogenation (PDH) to propylene has become one of the most promising and attractive techniques for the production of propylene because the success of the large‐scale exploitation of shale gas can supply an abundance of cheap propane for this process. Al2O3 is usually used as a support for PtSn catalysts to withstand the harsh reaction environment in the PDH process. However, due to the formation of coke and thermal agglomeration of metal particles, the PtSn catalyst suffers severe deactivation. Therefore, spinel supports are rationally designed with different morphologies (sphere, sheet, and rod) to stabilize the PtSn catalyst in the PDH. Specifically, the rod‐like spinel support exhibits a larger pore size and suitable interaction with PtSn nanoparticles shows an excellent C3H8 conversion rate of 43.2% and a C3H6 selectivity of 95.0% with an extremely low deactivation rate of 0.005 h−1 for the cycle test, standing as one of the best PDH catalysts reported to date and outperforming the commercial PtSn/Al2O3 catalysts. Besides, this catalyst is compatible with the industrial process to achieve scalable production.

Involvement of pyrolysis in the Orenburg gas chemical complex

Nowadays, there are no large production facilities to produce unsaturated hydrocarbons in the Orenburg region. Unsaturated hydrocarbons are produced in small quantities by PJSC “Orsknefteorgsintez” at the installation of hydrocracking, but this is not the target product and its quantity is minimal. Relying on this fact, we can assume that, by implementing the pyrolysis plant at the Orenburg gas-chemical complex, it is possible to make a worthy competition to existing enterprises, additionally provide the region with the product, and get more profit to the plant, as the cost of olefins is higher than that of the broad fraction of light hydrocarbons or individual components at its separation. The main production of propylene and butadiene is the process of thermal pyrolysis of hydrocarbon materials in tube-type furnaces in the presence of water steam. Unsaturated hydrocarbons can be obtained in other refining processes, but other plants produce unsaturated hydrocarbons in small quantities, which does not meet the demand for olefins. Based on the calculations and the analysis of the background, it can be concluded that the involvement of the NGL pyrolysis plant in the Orenburg gas chemical complex will allow more deeply processing non-targeted products and will be economically beneficial to the enterprise. The amount of produced propylene and butylene is comparable to the leading enterprises producing unsaturated hydrocarbons. These materials can be sold to neighboring regions for further processing and used for their own needs.

ZapSibNeftekhim modernizing PDH unit to boost Russian propylene production

Process safety has undergone a tremendous growth over the last decades, both in terms of required competencies and in terms of market demand. Although its cultural background mainly consists of the traditional subjects of chemical and process engineering, a multifaceted range of expertise has made it autonomous and different from the general chemical engineering frame: the interdisciplinary degree is much wider, the relevant regulations and standards have become so stringent and specific to become a key driver for the scientific and technical development of the discipline, its current growth trend is probably incomparable to others, role and functions of process safety engineers have acquired more significances and implications in the industrial scenario. This article considers the learning lessons of a long tutoring and teaching activity that the author has carried out in process safety between university and industry in Europe and in Asia. The findings have been analysed and converted into specific indicators and trend data, with the aim to contribute to reduce the significant gap which still exists in a branch of chemical engineering that is expected to increase its complexity and importance in the near future.

Stabilizing the isolated Pt sites on PtGa/Al2O3 catalyst via silica coating layers for propane dehydrogenation at low temperature

Catalytic conversion of propane to propylene can be achieved by non-oxidative propane dehydrogenation (PDH) by Pt-based catalysts under 550–700 °C. In this work, we report a strategy to decrease the Pt loading amount to only 0.1 wt% for obtaining a stable catalyst via silica coating for high PDH activity at a temperature as low as of 450 °C. The as-prepared 2.5%Si@PtGa/Al2O3 catalyst shows outstanding catalytic activity (propylene productivity rate 0.5 mol/gcat.·h) close to its equilibrium conversion (24.5%) with much better stability (deactivation constant: 0.007 h−1) at 450 °C. The interface between catalyst and silica coating changes the strong metal-support interaction (SMSI) to immobilize the Ga oxide clusters, further tightly anchoring the Pt catalytic sites for PDH process. Moreover, the electronic state of Pt is also influenced by the silica coating layers. This work demonstrates a new method to harnessing the metal-support interaction in catalysis.

Promoting propane dehydrogenation with CO2 over Ga2O3/SiO2 by eliminating Ga-hydrides

Due to the shortage supply of propylene and the development of shale gas, there is increased interest in on-purpose propane dehydrogenation (PDH) technology for propylene production. Ga-based catalysts have great potential in PDH, due to the high activity, low carbon deposit and deactivation. Ga-hydrides formed during PDH reduce the rate, selectivity and yield of propylene. In this contribution, CO2 is introduced into PDH as a soft oxidant to eliminate the unfavorable intermediate species Gaδ+-Hx re-generating Ga3+-O pairs, and also minimize coke deposition thereby improving the catalytic performance. In situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy experiments show that CO2 can effectively eliminate Gaδ+-Hx. At different temperatures, co-feeding CO2 during PDH over Ga2O3/SiO2 catalysts with different loadings significantly improves the stability of the conversion and selectivity, especially the latter, and provide a new dimension for improving the performance of PDH process.

High Promoting of Catalytic Cracking of Light Diesel by Au–Mn Modified ZSM-5 for Propylene Production

High Promoting of Catalytic Cracking of Light Diesel by Au–Mn Modified ZSM-5 for Propylene Production

The Economic Evaluation of Methanol and Propylene Production from Natural Gas at Petrochemical Industries in Iran

This investigation scrutinizes the economic features and potential of propylene and methanol production from natural gas in Iran because greenhouse gas emissions released by natural gas-based production processes are lower than coal-based ones. Considering the advantage of Iran’s access to natural gas, this study evaluates and compares the economic value of different plans to complete the value chain of propylene production from natural gas and methanol in the form of four units based on three price scenarios, namely, optimistic, realistic, and pessimistic, using the COMFAR III software. Iran has been ranked as the second most prosperous country globally based on its natural gas reserves. Methanol and propylene production processes via natural gas will lower the release of greenhouse gas. This, increasing the investment and accelerating the development of methanol and propylene production units driven by natural gas will lead the world to a low emission future compared to coal-based plants. The economic evaluation and sensitivity analysis results revealed that the conversion of methanol to propylene is more attractive for investment than the sale of crude methanol. The development of methanol to propylene units is more economical than constructing a new gas to propylene unit because of the lower investment costs.

Silicalite‐1 Supported ZnO as an Efficient Catalyst for Direct Propane Dehydrogenation

AbstractDirect propane dehydrogenation (PDH) is an attractive on‐purpose strategy for propylene production. Compared with high‐priced Platinum and toxic Chromium oxide, ZnO based catalysts attract wide attention due to its low‐cost and environment‐friendly character. Herein we report silicalite‐1 supported ZnO catalysts for PDH reaction. They exhibited an excellent catalytic performance. The catalyst with 5 wt% Zn exhibited the best propane yield with propane conversion reaching 49 % and propylene selectivity around 90 % at a space velocity of 5000 ml ⋅ g−1 ⋅ h−1. Characterization with N2 adsorption, XRD, SEM, TEM, EDS, NH3‐TPD, UV–vis, XPS, 29Si MAS NMR, FT‐IR, Py‐IR and TGA reveal that the high activity and stability can be attributed to the dispersed ZnO species due to the interaction between silanol nests of silicalite‐1 support and ZnO species. This study may open a promising way for development of highly efficient PDH catalysts.

Propylene Synthesis: Recent Advances in the Use of Pt-Based Catalysts for Propane Dehydrogenation Reaction

Propylene is one of the most important feedstocks in the chemical industry, as it is used in the production of widely diffused materials such as polypropylene. Conventionally, propylene is obtained by cracking petroleum-derived naphtha and is a by-product of ethylene production. To ensure adequate propylene production, an alternative is needed, and propane dehydrogenation is considered the most interesting process. In literature, the catalysts that have shown the best performance in the dehydrogenation reaction are Cr-based and Pt-based. Chromium has the non-negligible disadvantage of toxicity; on the other hand, platinum shows several advantages, such as a higher reaction rate and stability. This review article summarizes the latest published results on the use of platinum-based catalysts for the propane dehydrogenation reaction. The manuscript is based on relevant articles from the past three years and mainly focuses on how both promoters and supports may affect the catalytic activity. The published results clearly show the crucial importance of the choice of the support, as not only the use of promoters but also the use of supports with tuned acid/base properties and particular shape can suppress the formation of coke and prevent the deep dehydrogenation of propylene.

Electroassisted Propane Dehydrogenation at Low Temperatures: Far beyond the Equilibrium Limitation.

Propylene production by propane dehydrogenation (PDH) generally requires high temperatures due to thermodynamic equilibrium limitations. This study developed a novel type of catalytic system for low-temperature PDH by combining a surface protonics methodology with intermetallic active sites. By application of an electric current, the intermetallic Pt–In/TiO2 catalyst gave a propylene yield of 10.2% with high selectivity, even at 250 °C, where the thermodynamic equilibrium yield was only 0.15%. Electroassisted proton collisions with propane allowed an unusual reaction pathway for low-temperature PDH. Alloying of Pt with In drastically enhanced the activity and selectivity due to the increased electron density of Pt.

Bimetallic Ni-Zn site anchored in siliceous zeolite framework for synergistically boosting propane dehydrogenation

Propane dehydrogenation (PDH) is a prospective benign process for the production of propylene, but generally depends on high-price Pt and toxic Cr(VI) catalysts that often suffer from the rapid deactivation derived from metal sintering and severe coke deposition. To overcome these problems, the breakthroughs in an alternative catalyst design with efficient, low-cost and eco-friendly play a crucial role in successfully developing this process. Here, we facilely fabricate the bimetallic-site catalyst of Ni-Zn anchored in the zeolitic framework of silicalite-1 (depicted as NiZn-S-1) by employing ligand-protected strategy, which performs high temperature stability. Under comparable conditions, the NiZn-S-1 catalyst with high Ni/Zn molar ratio of 3:1 (named 0.2Ni0.06Zn-S-1) exhibits superior catalytic activity (initial propane conversion of 32.5 % and actual TOFpropane of 28.5 min−1) with low deactivation rate (0.0778 h−1) and great propylene selectivity (>90%) after 30 h on stream. In particular, the catalytic performance on this catalyst almost keeps same as that of fresh catalyst after 4 successive oxidation–reduction cycles. Multiple characterizations further demonstrate that the enhancement of PDH performance ought to be attributed to the synergistic effect between bimetallic Ni-Zn sites, which favors the selective activation of C–H bond and propylene desorption to reduce the formation of coke species with high graphitization degree, boosting the improvement of catalyst stability. The design of novel bimetallic-sites catalyst can give a new idea on the development of alternative PDH catalysts with economical- and environment-friendly in the future.

Al ion-exchanged USY in FCC catalyst for high LPG yield

Refineries, especially fluid catalytic cracking (FCC) units are required to increase propylene production because of changing demand from fuels to chemicals in recent years. We have found a promising FCC catalyst for such demand. The FCC catalyst with Al ion-exchanged USY zeolite (catalyst (Al)) has indicated the higher LPG yield without decreasing in the activity. The catalyst (Al) would be suppressing hydrogen transfer reactions between products or intermediates. Moreover, the olefins in the gasoline would be over-cracked to LPG over catalyst (Al) because of strong acidity of Al ion-exchanged USY.

Effect of Surface Oxidation on Oxidative Propane Dehydrogenation over Chromia: An Ab Initio Multiscale Kinetic Study.

An increasingly utilized way for the production of propene is propane dehydrogenation. The reaction presents an alternative to conventional processes based on petroleum resources. In this work, we investigate theoretically how Cr2O3 catalyzes this reaction in oxidative and reducing environments. Although previous studies showed that the reduced catalyst is selective for the non-oxidative dehydrogenation of propane, real operating conditions are oxidative. Herein, we use multiscale modeling to investigate the difference between the oxidized and reduced catalyst and their performance. The complete reaction pathway for propane dehydrogenation, including C–C cracking, formation of side products (propyne, ethane, ethylene, acetylene, and methane), and catalyst coking on oxidized and reduced surfaces of α-Cr2O3(0001), is calculated using density functional theory with the Hubbard correction. Parameters describing adsorption, desorption, and surface reactions are used in a kinetic Monte Carlo simulation, which employed industrially relevant conditions (700–900 K, pressures up to 2 bar, and varying oxidants: N2O, O2, and none). We observe that over the reduced surface, propene and hydrogen form with high selectivity. When oxidants are used, the surface is oxidized, which changes the reaction mechanism and kinetics. During a much faster reaction, H2O forms as a coproduct in a Mars–van Krevelen cycle. Additionally, CO2 is also formed, which represents waste and adversely affects the selectivity. It is shown that the oxidized surface is much more active but prone to the formation of CO2, while the reduced surface is less active but highly selective toward propene. Moreover, the effect of the oxidant used is investigated, showing that N2O is preferred to O2 due to higher selectivity and less catalyst coking. We show that there exists an optimum degree of surface oxidation, where the yield of propene is maximized. The coke, which forms during the reaction, can be burnt away as CO2 with oxygen.

Conversion of Methanol to Olefins over Modified OSDA-Free CHA Zeolite Catalyst

Methanol to olefins (MTO) is an essential process that produces olefins from both renewable and fossil fuels resources. Chabazite (CHA) is an efficient catalyst for MTO process due to its distinct properties that promote light olefins (i.e., ethylene and propylene) production. Herein, we report a series of chabazite-based catalysts (OSDA-free with enhanced textural properties) that facilitate the MTO reaction. The synthesized CHA was modified by steam injection (CHA-S), acid treatment (CHA-A), steam and acid treatment (CHA-SA), and metal incorporation (CHA-SA (Mg), CHA-SA (Ca), and CHA-SA (Ba)). The catalysts were characterized by several characterization techniques. The structure was investigated using X-ray diffraction (XRD) and nuclear magnetic resonance, while the morphology and physical properties were studied by field emission scanning electron microscopy (FE-SEM), N2 adsorption/desorption, and ammonia temperature-programmed desorption (NH3-TPD). The catalysts were evaluated at 450 °C until deactivation. CHA modified by only acid treatment showed higher selectivity to olefins from ca. 92 to 95 wt.% but suffered quick deactivation. CHA modified with both steam and then acid treatment was more stable in the MTO process.