Dehydrogenation Of Butane Research Articles

Simplified modeling of butane dehydrogenation: deeper understanding of the system’s dynamics

The dehydrogenation of butane is a catalytic process that involves the separation of hydrogen atoms from an organic molecule, and it relies on the presence of a catalyst Z, such as Ni, Pt, Pd, Fe, ZnO, Cr 2 O 3, or Fe 2 O 3. In this paper, we introduce two highly effective mathematical techniques known as Lumping Compartments (LC) and Intrinsic Low Dimensional Manifold (ILDM) to simplify the complexity of the dehydrogenation of butane. Initially, the model consists of seven nonlinear differential equations with eight parameters. To streamline the model, we applied LC to ten different cases, considering various initial states and parameters. As a result, the number of compartments significantly decreased from seven to three. The obtained computational results and total differences reveal a remarkable agreement between the complete model and the simplified version, demonstrating a high degree of predictive accuracy. Additionally, ILDM is employed to enhance the initial estimation of the slow invariant manifold. This enables us to easily distinguish between the fast and slow variations at each point, with the variations acting as chemical kinetics attractors. Fast chemical reactions are drawn towards these attractors, while slow chemical reactions occur within the manifolds.

Decoding the Kinetic Complexity of Pt-Catalyzed n-Butane Dehydrogenation by Machine Learning and Microkinetic Analysis

Decoding the Kinetic Complexity of Pt-Catalyzed <i>n</i>-Butane Dehydrogenation by Machine Learning and Microkinetic Analysis

Mechanism and Kinetics of Propane and n-Butane Dehydrogenation over Isolated and Nested ≡SiOZn–OH Sites Grafted onto Silanol Nests of Dealuminated Beta Zeolite

Mechanism and Kinetics of Propane and <i>n</i>-Butane Dehydrogenation over Isolated and Nested ≡SiOZn–OH Sites Grafted onto Silanol Nests of Dealuminated Beta Zeolite

Butane Dehydrogenation: Thermodynamic Modeling and Performance Analysis of Selected Process Simulators

The critical role of process simulation in modern chemical engineering cannot be overstated, with its capacity to facilitate process scale-up, assess alternative designs, and comprehend plant efficiency. This research delves into the performance of three software programs, Cape-Open to Cape-Open (CC), DWSim, and Aspen HYSYS (AH), in modeling butane dehydrogenation. The focus is on their ability to accurately model thermodynamic properties and chemical reaction dynamics. Butane dehydrogenation was evaluated with specific thermodynamic parameters using a Gibbs reactor model with Gibbs minimization. The Soave Redlich-Kwong thermodynamic model was employed to investigate the impact of temperature of 700 °C and pressures of 0.1 MPa and 1.0 MPa on the yield and selectivity of butadiene and butene. The CC and AH simulation results closely agreed with the available experimental data. The consistency of freeware simulators with a commercial simulator was also assessed, with AH serving as the reference standard. It was revealed that CC demonstrates higher consistency with it than DWSim under both low- and high-pressure conditions. This study confirms that CC is a reliable process simulator suitable for use in resource-constrained settings where expensive commercial licenses are prohibitive.

Engineering multi-component 3DOM FeVCrOx catalysts with high oxygen mobility for the oxidative dehydrogenation of 1-butene with CO2.

Oxidative dehydrogenation (ODH) of 1-butene with CO2 to 1,3-butadiene (BD) via Fe-based catalysts is a promising strategy, and the mobility of lattice oxygen plays a key role in the catalytic reaction. However, the catalytic activity of Fe-based catalysts is limited by the poor lattice oxygen mobility. To improve the mobility of lattice oxygen and optimize the ODH reaction, a series of 3DOM Fe-based catalysts (FeVAlOx, FeCrAlOx, and FeVCrAlOx) were prepared by PMMA template method. Among these samples, the multi-component FeVCrAlOx samples showed the best catalytic activity, and the 1-butene conversion of the multi-component catalyst could reach 88.3%, the BD yield could reach 27.5%. Further study found that the introduction of multi-component elements (V and Cr) not only promoted the formation of the γ-Fe2O3 phase but also formed more active components (V5+ and Cr6+). More importantly, the lattice oxygen mobility was also significantly improved. In addition, the reaction in the presence of water conditions was studied by activity tests and in situ DRIFTS tests. The results show that CO2 was present in the form of HCO3-. The utilization of CO2 was improved and the reaction path was changed.

Constructing mesoporous FeAlOx based catalysts through framework-confined strategy with superior performance for the oxidative dehydrogenation of 1-butene with CO2

The activation of oxygen species is always a challenging problem in the oxidative dehydrogenation (ODH) of 1-butene with CO2. The oxygen species play an important role in improving the conversion, yield, selectivity, and stability of FeAlOx-based catalysts. In this paper, the framework-confined (FC) strategy was used to active the oxygen species. The changed crystalline phase from Fe2O3 to FeAlO4 illustrated the introduction of Fe species destroyed the Al2O3 lattice and more active oxygen species were released. Compared with the WI-Fe2O3/Al2O3 samples, the ratio of active lattice oxygen was increased from 0.03 to 0.1 and the ratio of Fe3+ was also increased from 0.63 to 0.76 in the FC-FeAlOx samples. After doping with other metal species, the ratio of active lattice oxygen was further increased. The 1-butene conversion could reach 80 % and the 1, 3-Butadiene selectivity could reach 33 % over the FC-FeCrAlOx samples. Besides this, the FC-FeCrAlOx samples showed an outstanding thermal stability, which might be caused that Cr species could reduce the coke formation. The FC-FeCaAlOx samples had a higher utilization rate of CO2, which might be caused that Ca species could improve the basicity of the catalyst.

1,3-Butadiene Production by Simple Dehydrogenation of 1-Butene in the Presence of Steam Over Pt Supported on SnO2-Coated Al2O3

1,3-Butadiene Production by Simple Dehydrogenation of 1-Butene in the Presence of Steam Over Pt Supported on SnO2-Coated Al2O3

Engineering Specific Mo–O Bond Stretching to Activate Lattice Oxygen in V-Doped Bi2MoO6 for Enhanced Oxidative Dehydrogenation of 1-Butene

Structural distortion has been demonstrated to regulate lattice oxygen activity, but its precise regulation has always been a thorny problem, especially for the oxidative dehydrogenation of hydrocarbons. Herein, by synthesizing a series of V-doped Bi2MoO6 catalysts, mechanistic insight into the effect of structural distortion on the catalytic activity of oxidative dehydrogenation of 1-butene was provided. Comprehensive characterizations and kinetics tests revealed that the V-doped Bi2MoO6-induced active lattice oxygen initiates 1-butene activation by abstracting the C–H bond, which is a rate-determining step. Combined with density functional theory results, an overwhelming effect of the bond length between Mo and apical oxygen atom in the MoO6 octahedron on lattice oxygen activation and butadiene formation pathway was proposed. The stretching Mo–Oapical bond elicited by V doping enhances the abstraction of hydrogen and accelerates the redox cycle. The sample with a 5% V content possesses the maximum Mo–Oapical bond length, enabling superior catalytic performance at an 87.6% 1,3-butadiene yield.

Mathematical model development and simplification for multi-route complex chemical mechanism

A complete inventory and a clearly defined structure of any complex reaction mechanism are difficult to obtain. This paper addresses a complex catalytic cycle of dehydrogenation of butane in theoretical and computational beliefs. Mathematically, simplification is done by “model reduction,” that is, the rigorous way of approximating and representing a complex model in simplified form. Firstly, a simple single-route mechanism has been considered then a complex system is discussed in detail. The most practical and helpful way to represent a complicated system is using a simple model so that the model may be improved and transformed into a more accurate one that can be solved numerically. To reduce the complexity of a higher dimensional complex system, need to be a split reaction mechanism in different available routes. With the help of the concept of the multi-route model, we can reduce a complicated higher-dimensional system to a low-dimensional manifold and investigate each route independently. For model development and standardization, sensitivity analysis is a powerful tool used in this paper. The influence of parameters on target output is discussed through graphical results depicted in the symbology toolbox in MATLAB.

Promoting n-Butane Dehydrogenation over PtMn/SiO2 through Structural Evolution Induced by a Reverse Water-Gas Shift Reaction

Promoting <i>n</i>-Butane Dehydrogenation over PtMn/SiO₂ through Structural Evolution Induced by a Reverse Water-Gas Shift Reaction

Dehydrogenation of Propane and n-Butane Catalyzed by Isolated PtZn4 Sites Supported on Self-Pillared Zeolite Pentasil Nanosheets

Propene and 1,3-butadiene are important building-block chemicals that can be produced by dehydrogenation of propane and butane on Pt catalysts. A challenge is to develop highly active and selective catalysts that are resistant to deactivation by Pt sintering and coke formation. We have recently shown (Qi , J. Am. Chem. Soc. 2021, 143, 21364−21378) that these objectives can be met for propane dehydrogenation (PDH) using atomically dispersed Pt anchored to neighboring ≡SiOZn-OH groups bonded to the framework of dealuminated zeolite BEA. In the present study, we demonstrate that significantly superior performance can be achieved using self-pillared pentasil (SPP) zeolite nanosheets as supports. Following catalyst reduction in H2, atomic resolution, scanning transmission electron microscopy (STEM), and X-ray absorption spectroscopy (XAS) indicate that Pt is stabilized in structures well approximated as (≡Si-O-Zn)4-5Pt. These species are highly active, selective, and stable for PDH to give propene and for n-butane dehydrogenation (BDH) to give 1,3-butadiene. No catalyst deactivation was observed after 12 days of time on stream, and the selectivity remained at nearly 100% for PDH conducted at 823 K and a weight hourly space velocity (WHSV) of 1350 h–1. The apparent rate coefficient for PDH on this catalyst is significantly higher than that reported previously for Pt-containing catalysts. For BDH at 823 K and a WHSV of 3560 h–1, the selectivity to butene isomers and 1,3-butadiene is 98.9%, and the selectivity to 1,3-butadiene is 45%. We propose that the high catalyst stability observed during PDH and BDH is a consequence of a large fraction of the Pt-containing centers being located on the external surface of the zeolite nanosheets, where nascent coke precursors can desorb before condensing to form coke.

Butadiene production in membrane reactors: A techno-economic analysis

The direct dehydrogenation of butane (BDH) is emerging as an attractive on-purpose technology for the direct production of 1,3-butadine. However, its product yield is hindered by the high rate of carbon deposition associated to the high temperature required for the highly endothermic reaction. In this work, we evaluated the use of H2-selective membrane reactor, to increase the yield of the dehydrogenation process at milder operating conditions. The novel proposed membrane reactor (MR)-assisted BDH technology is compared from a techno-economic point of view with the benchmark technology. The results of this analysis reveal that the MR technology enables to work at milder operating temperatures (−85 °C), reducing carbon formation (−98.5%) and reactor duty (−10%). Due to the higher reaction yields, the MR-assisted BDH technology can lower the required shale gas-based feedstock, maintaining same production capacity as in the benchmark; this will result in an overall plant efficiency of 50.92% in the MR-assisted plant, compared to 37.7% of the benchmark case. This work demonstrates that MR-assisted technology is a valuable alternative to the conventional BDH technology, reducing of almost 20% the final cost of production of 1,3-butadiene, due to the lower installation costs and the higher energy efficiency.

Carbon Nanotubes Modified by BiMo Metal Oxides for Oxidative Dehydrogenation of 1-Butene to 1,3-Butadiene without Steam

Oxidative dehydrogenation (ODH) reaction has emerged as a promising route for converting 1-butene to value-added 1,3-butadiene (BD). However, the low BD selectivity of the current catalysts (≤40%) and high steam input are now the challenge of this process. Here, we demonstrate the fabrication BiMo oxides immobilized on carbon nanotubes (BiMo/CNTs), employing the sol–gel method, as a novel catalyst for the ODH of 1-butene without steam in a fixed-bed reactor. The catalytic performances of BiMo/CNTs with different compositions in the absence of steam were investigated. When BiMo/CNTs at a molar ratio of 0.018 were employed in the ODH of 1-butene under reaction conditions of 440 °C, 1-butene/oxygen = 1/0.8, and no steam, the optimal BD yield was achieved as high as 52.2%. Under this reaction condition, the catalyst maintains good stability without steam after 10 h of reaction. This work not only promotes the application of carbon materials in oxidative dehydrogenation reaction, but also accelerates the production of 1,3-butadiene in a more economical way.

The dehydrogenation of butane on metal-free graphene

The dehydrogenation of alkane feedstock to produce alkenes is a significant and energy intensive industrial process, generally occurring on metals and metal oxides. Here, we investigate a catalytic mechanism for the dehydrogenation of butane on single-layer, metal-free graphene using a combination of ab initio quantum chemical calculations and adsorption microcalorimetry. Dispersion-corrected Density Functional Theory (DFT) is employed to calculate transition states and energy minima that describe the reaction pathways connecting butane to the two possible products, but-1-ene and but-2-ene. The deprotonations occur with moderate energy barriers in the 0.54 eV-0.69 eV range. A strong agreement is observed between the results of the adsorption energies calculated by DFT (0.40 eV) and the measured differential heat of adsorption of n-butane on a graphitic overlayer. We conclude that the active-site for this catalytic reaction is a metal-free graphene vacancy, created by removing a carbon atom from a single-layer graphene sheet.

Mechanism and Kinetics of n-Butane Dehydrogenation to 1,3-Butadiene Catalyzed by Isolated Pt Sites Grafted onto ≡SiOZn–OH Nests in Dealuminated Zeolite Beta

An interest in the on-purpose production of 1,3-butadiene (1,3-BD) has grown, as a consequence of the decline in naphtha cracking for the production of ethene and propene, products that can now be produced economically by thermal dehydrogenation of ethane and propane contained in natural gas. In this study, the mechanism and kinetics of n-butane dehydrogenation to 1,3-BD are explored over atomically distributed Pt sites grafted onto dealuminated zeolite BEA (DeAlBEA) in the form of (≡Si–O–Zn)4–6Pt complexes. Reaction of n-butane dehydrogenation carried out at 823 K with 2.53 kPa n-butane/He and a weight-hourly space velocity (WHSV) of 14.5 h–1 produced 1,3-BD with a turnover frequency of 0.45 mol 1,3-BD (mol Pt)−1 s–1. Space-time studies and identification of the reaction intermediates suggest that n-butane first undergoes dehydrogenation primarily to 1-butene, which then rapidly isomerizes to produce an equilibrated mixture of 1-butene and 2-butene. 1-Butene then undergoes secondary dehydrogenation to produce 1,3-BD. We report, here, a detailed study of the kinetics of n-butane dehydrogenation to butenes and 1-butene dehydrogenation to 1,3-BD over isolated Pt sites. Both reactions exhibit a Langmuir–Hinshelwood dependence on n-butane and 1-butene partial pressures, respectively. Comparison of effective forward rate constants of n-butane dehydrogenation to butenes (k1f) and butene dehydrogenation to 1,3-BD (k2f) shows that the isolated Pt sites grafted onto DeAlBEA exhibit a very high activity for sequential dehydrogenation of n-butane to 1,3-BD relative to other Pt-based catalysts previously reported.

Catalytic Oxidative Dehydrogenation of Light Alkanes over Oxygen Functionalized Hexagonal Boron Nitride

AbstractThe catalytic activity of oxygen functionalized hexagonal boron nitride (h‐BN) with &gt;B−O−O−B&lt; and &gt;B−O−B&lt; active sites at the zigzag edges for oxidative dehydrogenation (ODH) of light alkanes, specifically ethane (C2H6), propane (C3H8), butane (C4H10), and isobutane (HC(CH3)3) is explored. It has been found that the reaction pathway involves two H atom transfer steps with small activation energies. We demonstrate that the synergy of two active sites, &gt;B−O−O−B&lt; and &gt;B−O−B&lt;, is crucial for the first and second H‐transfer, respectively. With the increase in molecular mass of the considered light alkanes, the ODH reaction temperature decreases. In the case of butane and isobutane, the ODH reaction occurs almost at the same temperature indicating that the reaction is independent of the shape of the isomer. The rate‐limiting nature of the first H‐transfer step is predicted. The charge redistribution during H‐transfers and localized oxygen atomic states in the conduction band are explored to suggest possible descriptors for the rational design of new catalysts. The universal action of the &gt;B−O−O−B&lt; and &gt;B−O−B&lt; active sites for ODH of the light alkanes paves the way for metal‐free BN‐based materials for future catalytic applications.

Metal-doped Cr2O3 as a catalyst for non-oxidative propane and butane dehydrogenation: A multiscale kinetic study

Molecules that are difficult to convert catalytically often require a complex and specially tailored catalyst composition. Catalytic alkane dehydrogenation is an interesting example, where theoretical ab-initio and kinetic meso-scale simulations can provide the understanding of the performance improvement when the catalyst composition is altered. Herein, we study non-oxidative dehydrogenation of propane and butane over variously doped (Na, Li, K, Mg, Ca, or Cs) chromium oxide using first principles. The reaction pathway for the conversion of propane to propene/propyne and of butane to 1- and 2-butene is studied using density functional theory with the Hubbard U correction. Energies and kinetic parameters describing the adsorption, desorption, and surface reactions are used in mean-field microkinetic and kinetic Monte Carlo simulations. The process was modeled at industrially relevant temperatures, pressures, and feed gas flow velocities. Calculating the catalytic conversion, selectivity to products, and activity trends show that surface doping enhances the conversion and activity. The highest conversion for most dopants is achieved at temperatures below 850 K and atmospheric pressure, where the activity is significantly improved compared to the non-doped Cr2O3 catalyst.

Thermodynamic Analysis on the Reaction of Oxidative Dehydrogenation of 1-Butene to 1, 3-Butadiene With CO2 as the Soft Oxidant

Thermodynamic Analysis on the Reaction of Oxidative Dehydrogenation of 1-Butene to 1, 3-Butadiene With CO2 as the Soft Oxidant

Oxidative Dehydrogenation of 1-Butene to 1,3-Butadiene Over Metal Ferrite Catalysts

The oxidative dehydrogenation (ODH) of 1-butene to 1,3-butadiene was studied over a series of AFe2O4 catalysts, where A = Zn, Mn, Ni, Cu, Mg and Fe. The catalysts were characterised by XPS, EPR spectroscopy, BET surface area analysis, Raman spectroscopy and XRD. All the ferrites were active for ODH and gave an order of activity after 80 h on-stream of ZnFe2O4 > NiFe2O4 > MnFe2O4 > MgFe2O4 > CuFe2O4 > FeFe2O4. All catalysts lost significant surface area (up to ~ 80%) under reaction conditions of 0.75:1:15 oxygen:1-butene:steam with an overall GHSV of 10,050 h−1 at 693 K. Fe3O4 was unstable under reaction conditions and was converted to Fe2O3, which showed very low activity. Nickel ferrite was the only material that gave carbon dioxide as a significant product, all others were selective to 1,3-butadiene. Zinc ferrite gave a steady-state yield of 1,3-butadiene of ~ 80%. Inversion parameters were determined for the ferrites from XPS and a correlation was obtained between 1,3-butadiene yield and inversion parameter, indicating that Fe3+ in an octahedral hole is a key species in the mechanism of oxidative dehydrogenation. Butene isomerisation and ODH were shown to occur on different sites.

Cooling effects of different molten salts and tube diameters on the performance of chemical reactors using butadiene synthesis as a case study

Many industrial applications adopt solar salt as the go-to heat transfer fluid for both cooling and thermal storage systems. However, the high melting temperature of this salt makes it economically unattractive. Hence, in this study, the investigation of 12 different molten salts was carried out to provide the right decision basis for selecting suitable salts for both cooling and thermal storage applications. In light of this, we developed a computational fluid dynamics (CFD) model to simulate butadiene synthesis via the oxidative dehydrogenation of butene in a single tube reactor equipped with a cooling jacket. The CFD model was validated against experimental results with an average error of 3.5%. Parametric studies involving the different salts indicated that low melting point salts resulted in high heat removal efficiencies but reduced the overall conversion, yield, and selectivity of the reactor due to the lower reaction temperatures. Thermophysical properties such as specific heat capacities were found to have no significant impact on the cooling efficiency of the reactor. An economic evaluation of the salts based on their heating costs indicated that salts of LiNaKCsCaNO3 and NaKCaNO3 are most suitable, especially for thermal storage systems where only latent heat of fusion is required. However, in cases where further heating of the salt is needed, higher melting point salts (such as solar salt) proved to be much more economical. Investigation of the effect of different tube diameters on the cooling performance of the reactor indicated that reactors having a diameter to length ratio between 32 and 58 provide sufficient cooling and high conversion.