Fixed-bed Catalytic Reactor Research Articles

The production of the hydro-processed renewable diesel (HRD) and its performances from a turbo-charged diesel engine

The development of the hydro-processed renewable diesel (HRD) is proposed in this study based on a lab-scale fixed-bed catalytic reactor. The HRD was produced at temperature of 380 °C, pressure of 6 MPa, weight hourly space velocity (WHSV) of 4.5 h−1 and hydrogen-to-oil ratio of 1000. The performance and emission characteristics of the pure diesel (D100), HRD blended diesel (20% HRD in diesel, H20) and biodiesel (20% biodiesel fuel blend, B20) have been evaluated with the help of turbo-charged diesel engine setup under steady-state operations. Investigations were conducted on regulated emissions including CO, CO2, HC, NOx and smoke. The addition of HRD did not evidently reveal a high impact on CO and NOx emissions. Compared with D100, the CO2 emissions of adding HRD have been reduced by 7.4%. The HC emissions for H20 were relatively lower than those for D100, especially at high engine speeds. Compared with the addition of biodiesel, the smoke reduction of HRD was more significant. The overall average opacity of D100 and B20 were 4.055% and 2.689%, respectively, while the overall average opacity of H20 was only 0.277%. The engine using B20 or H20 mixed fuel can achieve performance close to that of the engine using D100 fuel, since the braking thermal efficiency was close to a value of about 34%. H20 fuel provided better combustion stability than D100 since the average coefficient of variation (COV) of H20 was 0.81% and the average COV of D100 was 0.90%. H20 is better than pure diesel and B20 in terms of engine performance.

Integrated intelligent neuro computing technique for mixed convective flow and heat transfer in heterogeneous permeability media

This article examines the flow and heat transfer characteristics of variable permeability such as linear, exponential and quadratic permeability functions with Brinkmann–Forchheimer extended Darcy model by utilizing the intelligent computing paradigm via artificial Levenberg–Marquardt back propagated neural networks (ALM – BPNNs). The vertical porous channel walls are considered as electrically conducting and non-conducting. The variable permeability and induced magnetic field effects are significant on flow and heat transfer. To solve the obtained governing equations, finite element method is adopted. It is observed that for the three cases of permeability functions, increase in Hartmann number drops the velocity profile and is accompanied with an increase in the fluid thermal state level. The significance of the Brinkmann number on the fluid temperature in all the cases of permeability indicates a rise in temperature due to increased heat generation. But, the reverse effect is observed when the mixed convection parameter rises, and the boundary layer thickness reduces due to which temperature drops for distinct cases of permeability under consideration. The heat transfer characteristics are analyzed through an artificial neural network and multiple linear regression models. The present work finds its applications in studying packed bed heat exchangers and fixed-bed catalytic reactors.

Analysis of the Effectiveness Factor in a Fixed-Bed Tubular Reactor System: Catalytic Dehydrogenation of Cyclohexanol

The modeling and simulation of the catalytic dehydrogenation process of cyclohexanol in a fixed-bed catalytic reactor is presented, leading to finding the relationship between the effectiveness factor, the Thiele modulus, and the Weisz–Prater modulus of the catalyst particles with respect to their axial and radial position, for which the external conditions of concentration and temperature around each particle were previously obtained by applying the material and energy balances in the catalyst bed considering a two-dimensional pseudo-homogeneous model with radial diffusion. Subsequently, the material balances are established in terms of the molar flux density and conversion, the energy balance in terms of the heat flux density, Fick’s law, Fourier’s law, and the differential form of the effectiveness factor non-isothermal for each particle chosen based on the proposed meshing. The Thiele modulus calculated for most of the points is between 0.8 and 0.25, with a tendency towards the lower limit, and the theoretical values established as the limit for the Thiele modulus fluctuate between 0.4<Th<4. Therefore, the effectiveness factor analyzed is between 1 and 1/Th; this indicates that both the reaction speed as well as the diffusion speed within the particle have an influence on the intraparticle process, which is confirmed by the calculation of the Weisz–Prater modulus whose values are not <<1 nor >>1. The results obtained are subjected to a statistical test leading to analyzing whether there are significant differences both in the Thiele modulus, as well as in the effectiveness factor with respect to the radius and length of the reactor. It has been determined that there are no significant differences between the effectiveness factor with respect to the radius of the reactor; however, according to the analysis of variance, there are significant differences in the effectiveness factor with respect to length and, likewise, there are significant differences in the Thiele modulus and the Weisz–Prater modulus with respect to radius and length.

A novel method for the globally optimal design of fixed bed catalytic reactors

Fixed bed reactors are usually designed using simulation approaches by trying different dimensions as well as operating conditions followed by verification if the desired conversion is achieved. This trial and verification procedure does not guarantee optimality, just a feasible and reasonably good design (depending on the expertise of the designer). Cost minimization or profit maximization using optimization procedures is more rigorous, but it has been rarely employed. The methods usually employed in the literature for solving this design problem present limitations. In this article, we solve the design problem of fixed bed catalytic reactors globally. We use Partial Set Trimming followed by Smart Enumeration, a recently developed rigorous global optimization procedure. The reactor investigated is composed of a tube bundle, filled with a catalyst, inside a shell containing boiling water. We compare the performance of the proposed approach with the use of metaheuristics-based tools, which do not guarantee optimality.

Temperature distribution in a gas-solid fixed bed probed by rapid magnetic resonance imaging

Controlling the temperature distribution inside catalytic fixed bed reactors is crucial for yield optimization and process stability. Yet, in situ temperature measurements with spatial and temporal resolution are still challenging. In this work, we perform temperature measurements in a cylindrical fixed bed reactor by combining the capabilities of real-time magnetic resonance imaging (MRI) with the temperature-dependent proton resonance frequency (PRF) shift of water. Three-dimensional (3D) temperature maps are acquired while heating the bed from room temperature to 60 °C using hot air. The obtained results show a clear temperature gradient along the axial and radial dimensions and agree with optical temperature probe measurements with an average error of ± 1.5 °C. We believe that the MR thermometry methodology presented here opens new perspectives for the fundamental study of mass and heat transfer in gas–solid fixed beds and in the future might be extended to the study of reactive gas–solid systems.

Study of Catalytic Properties of the HoxMg1-xAl2O4 Modified HZSM-5 Zeolite in Conversion of Methanol to C2-C4 Alkenes and p-Xylene

Selective conversion of methanol to C2-C4 alkenes and p-xylene is one of the appealing chemical routes. Currently, there are no effective catalysts for the co-production of C2-C4 alkenes and p-xylene from methanol. To date, modified medium-pore ZSM-5 zeolites are considered one of the excellent candidates for the development of selective catalysts for the conversion of methanol to lower alkenes and aromatic hydrocarbons. In this paper, nanosized (30-33nm) powders of HoхMg1-хAl2O4 spinel structure were obtained by the method of combustion of nitrate solutions of aluminium, magnesium, holmium, diethylmalonate and hydrazine monohydrate with the further calcination of nanopowders at 1000 °C. Obtained nanopowders used in the preparation of a solid-phase catalytic composition of HoхMg1-хAl2O4-HZSM-5. Various physico-chemical properties of the catalytic composition were investigated using X-ray diffraction (XRD), pyridine adsorption (BİO-RAD FTS 3000 MX) and low-temperature nitrogen adsorption (BET) techniques. The textural properties and acidity of the catalysts were altered by adjusting the nanopowder concentration (1.0-5.0 wt.%) in the catalytic composition. The conversion of methanol in the presence of the catalytic compositions was carried out in flow-type fixed-bed catalytic reactor at 400 °C, in the presence of nitrogen carrier gas with 1.0 h-1 flow rate. A correlation between the selectivity to C2-C4 alkenes and p-xylene with a ratio of Lewis (L) and Brønsted (B) acid sites and the volume of the catalyst pore, the amount of the modifier in the catalytic system has been established. As the amount of HoхMg1-хAl2O4 nanopowder increases, the ratio of B/L acid sites and the volume of the catalyst pore decrease, which play a significant role in the increase of the selectivity to C2-C4 alkenes and p-xylene. Maximum yield of C2-C4 alkenes (31.6%) and selectivity to p-xylene (80.5%) is achieved on a catalytic composition containing 5.0 wt.% HoxMg1-xAl2O4. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Synergistic interaction of metal loaded multifactorial nanocatalysts over bifunctional transalkylation for environmental applications

A feasible and cost-effective process for utilization of toluene and heavy reformate is the conversion of its streams by transalkylation reaction into highly valuable xylenes. The process is usually catalysed by zeolites and the challenges to overcome in transalkylation of heavy reformate with toluene over zeolites are their selectivity, activity, long-term stability, and coke formation. Current study aimed to investigate xylenes production by transalkylation reaction on the synthesized metal-doped zeolite catalysts and to characterize prepared catalysts by FTIR, SEM, EDS and BET analysis. Toluene/heavy reformate modelled mixture was utilized as a feed. For the first time Beta and ZSM-5 catalysts with 10% (w/w) cerium and 0.1% (w/w) palladium were synthesized by calcination and wet impregnation method. Catalytic tests were performed by continuous-flow gas/solid catalytic fixed bed reactor at atmospheric pressure, 2 h−1 and 5 h−1 and 250, 300, 350 and 400 °C. Experimental results revealed that the highest heavy reformate conversion (98.94%) and toluene conversion (9.82%) were obtained over H-ZSM-5, at 400 °C and 2 h−1 WHSV. The highest xylene selectivity (11.53) was achieved over H-ZSM-5, and the highest p-xylene percentage (62.40%), using Ce-ZSM-5 catalyst. ZSM-5 catalysts showed more resistance to coke deposition than Beta zeolites. The present study delivers novel approach and catalysts, which have immense potential for developing safer and inexpensive transalkylation process in industry.

A study on the production and engine analysis of organic liquid fuel from jatropha and castor oil by catalytic cracking over solid acid catalysts

Catalytic cracking of non-edible oils such as jatropha and castor was done in fixed bed catalytic reactor. The microporous catalysts such as Hβ, HY and HZSM-5 and mesoporous catalyst like AlMCM-41 were synthesised and characterised by XRD and BET surface area analyzer. The reaction parameters such as temperature of reaction, WHSV (Weight hourly space velocity) and reaction time were optimised over Hβ catalyst using jatropha oil. Organic liquid products (OLP) comprising of green gasoline (GG), green kerosene (GK) and green diesel (GD) and gaseous products were found to be major products. The liquid products were analysed using gas chromatograph (Shimadzu GC-9A) fitted with Apeizon-L packed column and gaseous products were analysed using Poropak Q column. The % conversion, yield of OLP and selectivity towards GG, GK and GD were found to be higher at temperature of 400 °C, WHSV of 4.8 h−1 and reaction time of 1 h. The cracking of jatropha oil was done over HY, HZSM-5 and AlMCM-41 at this optimised condition. Among the microporous materials HZSM-5 produced more OLP with more selectivity towards GG fraction (50%) but yielded higher % of gaseous products. While AlMCM-41 (Si/Al = 25) was selective towards middle distillates fraction like GK (45%) & GD (35%) and yielded low gaseous products. The mechanism of reaction proceeds via carbocation formation. The activity of HZSM-5 and AlMCM-41 were examined with castor oil. The OLP viability as a replacement fuel in a single-cylinder diesel engine under various loads was evaluated in an IC engine test. Here, we look at how different engine operating conditions affect fuel efficiency, Brake Thermal Efficiency (BTE), and emissions of Carbon Monoxide (CO), Carbon-di-oxide (CO2) and Nitrogen Oxide (NOx). Overall analysis indicates that OLP cracked from Jatropha oil serves as a best fuel in comparison with OLP obtained from Castor oil.

Comparison of different sampling and surrogate modelling approaches for a multi-objective optimization problem of direct dimethyl ether synthesis in the fixed-bed reactor

It is a difficult task to select one proxy model with the proper range of accuracy and speed among various models. In the current study various types of sampling and surrogate models of a catalytic fixed-bed reactor (direct synthesis of DME) have been compared to perform a multi-objective optimization problem based on data. The challenge is to present a proper model which is capable of introducing a group of optimum points (as the Pareto front) in a single run in a multi-objective optimization problem based on Genetic Algorithm (GA) with comparable accuracy to the exact model but lower computational time during optimization. The initial database has been produced by different sampling methods. By applying the proposed method, the Pareto Front using surrogate models is achieved faster than the exact model, with quite satisfying accuracy. Different types of errors have been studied in sampling methods such as Random, Latin Hypercube Sampling (LHS), Sobol, and Halton, as well as alternative models, Linear Regression, Multilayer Perceptron Neural Network (MLP), Radial Basis Function Neural Network, Support Vector Regression, and Automatic Learning of Algebraic Models (ALAMO). Obtained results indicated that LHS as the sampling method and MLP and ALAMO as the surrogate models have the best ability to predict and optimize the steady-state behavior of the direct dimethyl ether synthesis in the fixed-bed reactor with the lowest mean square error (MSE) of 0.00027.

High-entropy alloy anode for direct internal steam reforming of methane in SOFC

High-entropy alloy (HEA) anode and reforming catalyst, supported on gadolinium-doped ceria (GDC), have been synthesized and evaluated for the steam reforming of methane under SOFC operating conditions using a conventional fixed-bed catalytic reactor. As-synthesized HEA catalysts were subjected to various characterization techniques including N2 adsorption/desorption analysis, SEM, XRD, TPR, TPO and TPD. The catalytic performance was evaluated in a quartz tube reactor over a temperature range of 700–800 °C, pressure of 1 atm, gas hourly space velocity (GHSV) of 45,000 h−1 and steam-to-carbon (S/C) ratio of 2. The conversion and H2 yield were calculated and compared. HEA/GDC exhibited a lower conversion rate than those of Ni/YSZ and Ni/GDC at 700 °C, but showed superior stability without any sign of carbon deposition unlike Ni base catalyst. HEA/GDC was further evaluated as an anode in a SOFC test, which showed high electrochemical stability with a comparable current density obtained on Ni electrode. The SOFC reported low and stable electrode polarization. Post-test analysis of the cell showed the absence of carbon at and within the electrode. It is suggested that HEA/GDC exhibits inherent robustness, good carbon tolerance and stable catalytic activity,` which makes it a potential anode candidate for direct utilization of hydrocarbon fuels in SOFC applications.

Synthesis of a Cu/Zn-BTC@LTA derivatived Cu–ZnO@LTA membrane reactor for CO2 hydrogenation

Methanol (MeOH) formation from CO2 hydrogenation has attracted increasing interest for CO2 reduction and utilization. However, CO2 conversion to methanol production is greatly blocked because of the thermodynamical restriction and catalyst inactivation caused by by-product water. In this work, we develop a Cu/Zn-BTC@LTA derivatived Cu–ZnO@LTA catalytic membrane reactor (CMR) for methanol production via CO2 hydrogenation. Through the successive separation of the by-product steam from the reactor by using a water-selective LTA membrane, the thermodynamic restriction is broken to promote CO2 transformation and methanol production. At 533 K and 3.00 MPa, a high CO2 conversion (49.1%) as well as methanol selectivity (90.2%) is obtained in the catalytic membrane reactor, which are much higher than the corresponding CO2 conversion (26.2%) and methanol selectivity (50.6%) obtained in the catalytic fixed bed reactor (CFBR). Further, catalyst deactivation induced by water can be effectively repressed in the catalytic membrane reactor, which is helpful to keep a high stability of the catalyst.

Synthesis of Cu–ZnO–Pt@HZSM-5 catalytic membrane reactor for CO2 hydrogenation to dimethyl ether

CO2 hydrogenation to dimethyl ether (DME) has drawn increasing interest in science and industry. However, the conversion of CO2 to DME is challenging due to the limitation of thermodynamic equilibrium and the water-induced degradation of the catalysts in a catalytic fixed bed reactor (CFBR). In this study, a novel reaction-separation coupling Cu–ZnO–Pt@HZSM-5 catalytic membrane reactor (CMR) was fabricated for CO2 hydrogenation to DME. Owing to continuous separation of the by-product steam by using an HZSM-5 membrane, the limitation of thermodynamic equilibrium can be broken effectively, thus leading to a substantially enhanced CO2 conversion (from 24.9% in the CFBR to 41.1% in the CMR) and DME selectivity (from 53.7% in the CFBR to 100% in the CMR). Further, water-induced degradation of the catalyst can be restrained because of water removal, thus keeping a high catalytic activity for a long time.

Analysis of CaCO3 Impregnation on HY Zeolite Surface Area, Pore Size, and Activity in the Catalytic Cracking of Palm Oil to Biofuels

Fossil energy sources are currently decreasing, requiring the development of alternative energy sources. Vegetable oil is a raw material for alternative renewable energy supplies. This study produced biofuels from vegetable oil using calcium carbonate (CaCO3)-impregnated HY catalysts. In addition, this study aimed to investigate the effect of CaCO3 impregnation on the surface area and the catalytic activity of catalysts in the palm oil cracking process to produce biofuels. The HY catalyst was modified by the wet impregnation method in 5 wt% CaCO3 solution and was further calcined at 550°C for three h. Furthermore, the catalysts were tested in a continuous fixed-bed catalytic reactor at 450°C. The catalyst properties were characterized using Brunauer–Emmett–Teller (BET) surface area, Barrett–Joyner–Halenda (BJH) for pore size distribution, and X-Ray Diffraction (XRD) for crystal structure and phases. The results showed that the addition of CaCO3 decreased surface area and pore volume; however, the pore size increased, which resulted in the production of heavy hydrocarbons. Interestingly, the introduction of CaCO3 enhanced the yield of Organic Liquid Product (OLP) and diesel-range hydrocarbons selectivity to reach 79.09% and 30.54%, respectively. Furthermore, the introduction of CaCO3 increased deoxygenation activity.

Design and Development of a Catalytic Fixed-Bed Reactor for Gasification of Banana Biomass in Hydrogen Production

Hydrogen produced from biomass is an alternative energy source to fossil fuels. In this study, hydrogen production by gasification of the banana plant is proposed. A fixed-bed catalytic reactor was designed considering fluidization conditions and a height/diameter ratio of 3/1. Experimentation was carried out under the following conditions: 368 °C, atmospheric pressure, 11.75 g of residual mass of the banana (pseudo-stem), an average particle diameter of 1.84 mm, and superheated water vapor as a gasifying agent. Gasification reactions were performed using a catalyzed and uncatalyzed medium to compare the effectiveness of each case. The catalyst was Ni/Al2O3, synthesized by coprecipitation. The gas mixture produced from the reaction was continuously condensed to form a two-phase liquid–gas system. The synthesis gas was passed through a silica gel filter and analyzed online by gas chromatography. To conclude, the results of this study show production of 178 mg of synthesis gas for every 1 g of biomass and the selectivity of hydrogen to be 51.8 mol% when a Ni 2.5% w/w catalyst was used. The amount of CO2 was halved, and CO was reduced from 3.87% to 0% in molar percentage. Lastly, a simulation of the distribution of temperatures inside the furnace was developed; the modeled behavior is in agreement with experimental observations.

Pseudoionone synthesis from citral and acetone in a fixed bed catalytic reactor with lanthanum modified calcium oxide

The industrial process of pseudoionone synthesis from citral uses a homogeneous catalyst with excessive acetone as a solvent-cum reactant in a stirred tank batch reactor which needs to be replaced by a better heterogeneously catalyzed, solventless, and ecofriendly flow process as shown by the current work.

Liquid phase hydrogenation of phenol catalyzed by silica supported palladium to yield cyclohexanone

In the work, liquid phase hydrogenation of phenol reaction was carried out using an isothermal fixed bed catalytic reactor. The catalyst was prepared by wet impregnation of palladium precursor onto silica gel support. The effect of reaction parameters such as catalyst particle size in the range of 1–2 mm, time factor (in terms of contact time of catalyst with reactant feed) in the range of 60–250 g.min/mole, and reaction temperature in the range of 80–130 °C on the conversion of phenol and selectivity towards cyclohexanone was studied. From the results, it was observed that the conversion of phenol and selectivity of cyclohexanone were increased with the decrease of catalyst particle size. Further it was observed that the phenol conversion increased with the increase in reaction temperature from 80 to 110 °C and time factor. However, the conversion was decreased with increase in reaction temperature beyond 110 °C. A decreased trend was observed for selectivity of cyclohexanone with the increase of reaction temperature and time factor. The obtained maximum conversion of phenol was around 92% with a cyclohexanone selectivity of more than 99% at an optimum temperature of 110 °C and contact time of 250 g.min/mole in presence of Pd/SiO2 catalyst at hydrogen-to-phenol mole ratio of 1:4. It was observed furthermore that the conversion of phenol and selectivity of cyclohexanone was higher for 1 mm catalyst particle size when compared to 2 mm catalyst particle size. From the results, it can also be concluded that the developed empirical models to predict conversion of phenol and selectivity towards cyclohexanone were good in agreement with the experimental data.

Sustainable hydrogen production via glycerol steam reforming using Ni/CeO2/ZrO2/Al2O3 catalysts

The present study focuses on catalytic promoters to optimize parameters for hydrogen generation using glycerol, through the steam reforming process. Ceria and zirconia have been investigated and experimented with as promoters for the nickel catalysts over Al2O3. The catalysts, with different ceria and zirconia compositions, were prepared by co-precipitation and wet impregnation methods. Different techniques were employed for the characterization of synthesized catalysts, including XRD, SEM and FT-IR analysis. The performance of catalysts was evaluated in atmospheric gas–solid fixed-bed catalytic reactor. Different operating conditions were tested and evaluation of kinetics associated with reactions was carried out using the power-law model to analyse the performance of catalysts. Parameters and cause of catalyst deactivation were also investigated and process conditions were modified to avoid catalyst deactivation. Obtained results stated that catalyst with metal proportions as Ni/Ce/Zr/Al: 10/3/2/85 proved to be a suitable one with activation energy found to be 73.93 kJ/mole. Hydrogen selectivity and CO selectivity during water gas shift reaction were parameters upon which optimization of Ce/Zr ratio was experimentally obtained, to take advantage of zirconia due to its selectivity and ceria with its dispersion over nickel. Coke formation was found to be a major cause of catalyst deactivation and excess steam use was subjected to eliminate it.

Accelerating particle-resolved CFD simulations of catalytic fixed-bed reactors with DUO

Simulation of fixed-bed catalytic reactors is important for engineering industrial technologies. The large number of catalytically active surface faces makes the application of microkinetic models too time consuming for large 3D simulations that include fully resolved particle structures (e.g., ≫ 10′s of particles). Such simulations, though, are often required for small tube-to-particle diameter ratio configurations, where local flow effects are difficult to capture with 1D or 2D simulations. A common solution for speeding up reactive computational fluid dynamics (CFD) involves the use of chemistry acceleration methods, including In-Situ Adaptive Tabulation (ISAT) and Cell Agglomeration (CA). In the present contribution, DUO (DETCHEMTM + OpenFOAM coupling) CFD software has been extended to include ISAT and CA methods for surface reactions, in particular, using a CA method that is simpler than other implementations of this acceleration technique. Speedup factors and errors were tabulated for an 86 spherical particle 3D resolved fixed-bed reactor, considering the exothermic methane catalytic partial oxidation (CPOX) and the endothermic dry reforming of methane (DRM) chemistries. For CPOX, a speedup factor of ∼ 7x was achieved, while for DRM, a speedup of ∼ 35x was obtained, with both cases achieving an acceptable error in the solution. Although a tighter error tolerance with ISAT and CA is shown to reduce the overall calculation error, for some engineering situations this tradeoff in speedup and accuracy will be acceptable. Achieving usable results in around 0.5 – 2 h instead of around 20-hours (for these chemistries on this particular grid, run on a 400-core cluster) can vastly improve the feasibility of computational fluid dynamics for the analysis of fixed-bed catalytic reactors including microkinetics mechanisms.

Ethylene and cyclohexane co-production in the fixed-bed catalytic membrane reactor: Experimental study and modeling optimization

In this study, a fixed-bed catalytic membrane reactor was used for the production of ethylene and cyclohexane from ethane and benzene. A two-dimensional non-isothermal mathematical model was used for estimating the performance of the membrane reactor. Furthermore, the effect of inlet temperature (720–1080 K), feed molar ratio (3–10) and the reactor spacetime (1–76 kgCat.s/mol) was studied on the conversion of ethane to ethylene and benzene to cyclohexane. The results of modeling showed that with the increase of inlet temperature the conversion of both (de)-hydrogenation reactions increased and the 95% of ethane conversion was achieved when the molar ratio of benzene/ethane was fixed on 3. The hydrogenation of benzene at the shell side of the catalytic membrane reactor enhanced the production of ethylene due to the exothermic nature of the hydrogenation reaction, resulting in heat conduction through the membrane and glass substrate into the tube side. The comparison between experimental data reported in literature and modeling showed that the deviation of data obtained by mathematical modeling from experimental values ranged from 15.2 to 19.8% at various spacetimes. In addition, the results of sensitivity analysis showed that the conversion of benzene and ethane is more sensitive to the inlet temperature (up to 160% change on conversion) in comparison to the other parameters including feed ratio and the reactor spacetime. Moreover, at a temperature above 1128 K, the overall performance of the catalytic membrane reactor increased significantly.

Experimental verification of a pilot pyrolysis/split product gasification (PSPG) unit

In this study, effectiveness of a thermo-catalytic waste and biomass gasification unit consisting of a pyrolysis stage and a split product gasification stage (PSPG) was verified considering: increase of gas lower heating value (LHV), reduction of gas tar content (GTC), increase of cold gas efficiency (CGE) and carbon conversion efficiency (CCE). The unit consisted of three reactors: an auger pyrolysis reactor (PR), fixed-bed char gasification reactor (CHGR) and fixed-bed secondary catalytic reactor (SCR). A low-cost natural clay-based catalyst and a natural zeolite were used in the secondary catalytic reactor. Tar content in syngas and tar yield were significantly affected by the air split ratio. Splitting air between SCR and CHGR reduced the syngas tar content and gasification tar yield. Suitable equivalence ratio and air split ratio in the studied region were 0.1595 and 0.325, respectively. At these ratios, the highest LHV/GTC value was achieved (2.01), CGE was 62.33%, CCE 80.90%, and feed conversion was 94.15%. Tar concentration in syngas was 3.64 g.Nm−3 and tar yield was 5.21 g kg−1. The lower heating value of syngas was 7.34 MJ.Nm−3. To find overall optimal process conditions, higher equivalence and air split ratios will have to be studied.