Catalytic Reforming Of Methane Research Articles

Catalytic reforming of methane with H2S via dynamically stabilized sulfur on transition metal oxides and sulfides

Catalytic reforming of methane with H2S via dynamically stabilized sulfur on transition metal oxides and sulfides

The CREC Fluidized Riser Simulator a Unique Tool for Catalytic Process Development

The CREC Riser Simulator is a mini-fluidized bench scale unit invented and implemented in 1992, at the CREC (Chemical Reactor Engineering Centre), University of Western Ontario The CREC Riser Simulator can be operated at short reaction times, in the 3 s to 20 s range. The present review describes and evaluates the original basic concept of the 1992-CREC Riser Simulator Unit, and the improved design of the 2019-CREC Riser Simulator. Both the initial and the enhanced units are specially engineered to allow the rigorous assessment of both catalyst performance and catalytic reaction kinetics. Kinetic parameters of relatively simple and accurate mathematical models can be calculated using experimental data from the CREC Riser Simulator. Since its inception in 1992, the CREC Riser Simulator has been licensed to and manufactured for a significant number of universities and companies around the world. Several examples of scenarios where the CREC Riser Simulator can be employed to develop fluidized bed catalytic and heterogeneous reactor simulations are reported in this review. Among others, they include (a) hydrocarbon catalytic cracking, (b) the catalytic conversion of tar derived biomass chemical species, (c) steam and dry catalytic methane reforming, (d) the catalytic oxydehydrogenation of light paraffins, (e) the catalytic desulfurization of gasoline, and (f) biomass derived syngas combustion via chemical looping. In this review, special emphasis is given to the application of the CREC Riser Simulator to TIPB (tri-iso-propyl-benzene) catalytic cracking and the light paraffins catalytic oxydehydrogenation (PODH).

Influence of gas atmosphere and role of tar on catalytic reforming of methane and tar model compounds: Special focus on syngas produced by sorption enhanced gasification

Combining sorption enhanced gasification (SEG) of biomass with a downstream reformer leads to high-quality syngas for hydrogen production and synthesis applications. Reforming of methane and tar model compounds (toluene and naphthalene) at various parameters and in simulated SEG environments was thus examined for reaching maximum conversion of hydrocarbons to enhance H2/CO production. This was studied by means of thermodynamic analyses and experiments using a Ni-based catalyst in a fixed bed reformer. Simulation and experimentation indicate that the high steam-to-carbon ratio of SEG syngas promotes the high conversion of hydrocarbons. The high hydrogen concentration inhibits the methane-steam reaction but improves CO yield. Experimentally, the presence of tar model compounds at 600 °C reduced methane conversion by approximately 30%, and deactivation of catalysts by carbon formation was detected. The deactivation resulted in significant drops in toluene and naphthalene conversions over time, while methane conversion remained almost stable. Furthermore, the heavier tar compound, naphthalene, showed an inhibition effect on toluene and methane reforming. The results implicate the significance of studying different hydrocarbons in the reforming process. Overall, to completely convert all hydrocarbons in the SEG syngas for more H2/CO production, a high reforming temperature of 800 °C for the applied Ni-based catalyst is recommended. No additional steam is required in a reformer due to the typical composition of SEG syngas.

Selective Catalytic Reforming of Methane into Synthesis Gas

AbstractSyngas is an important product of methane processing of natural gas, from which a wide range of chemical products can be obtained in the future. The results of a study of the developed Ni multicomponent catalysts in the partial oxidation of CH4 to syngas are presented. A series of samples with different percentages of active components in a Ni‐Cr‐Al‐Mg‐glycine catalyst was prepared by the solution combustion synthesis method giving synthesis gas with a high yield. The optimum conditions for the highest yields of H2 and CO were identified.

Ruthenium-Exsolution Catalyst for Dry Reforming of Biogas

When biogases are directly used as fuels in SOFCs, catalytic reforming of methane into hydrogen and carbon monoxide occurs at the nickel anode. This may expose the anode to localized cooling and a high risk of carbon deposition. These issues can be tackled by preprocessing the biogas. Diluting it with steam or CO2 recovered from the SOFC anode off-gas may suppress the risk of carbon deposition whereas reforming it externally can protect the cell from thermal instabilities while offering additional protection against contaminants. Ruthenium has an outstanding catalytic activity with demonstrated coking resistance. Its cost however limits its use. In this work, dry reforming of diluted biogases was performed on a low-ruthenium-exsolution catalyst. An approach by total material balance allowed to determine near 100% methane conversion at GHSV up to 2000 h-1 while the reaction was close to the computed thermodynamic equilibrium.

Hierarchical Layered Porous SiO2 Supported Bimetallic NiM/EXVTM-SiO2 (M = Co, Cu, Fe) Catalysts Derived from Vermiculite for CO2 Reforming of Methane

In this study, the two-dimensional layered porous silica material (EXVTM-SiO2) was designed and prepared by “expansion-acidification” modified vermiculite. Herein, NiM/EXVTM-SiO2 (M = Co, Cu, Fe) bimetallic catalysts were prepared by the incipient wetness impregnation method. Three kinds of bimetallic catalysts were used in methane reforming. The catalysts were characterized by techniques such as XRF, ICP, XRD, BET, SEM, TEM, XPS, H2-TPR and TG. It was found that NiCu/EXVTM-SiO2 catalyst had high catalytic activity and stability, and the conversion of CO2 was up to 92%, which realized the efficient catalytic conversion of CO2. On the one hand, the reason can be attributed to the fact that the active metal in the NiCu/EXVTM-SiO2 catalyst has a smaller particle diameter (10.6 nm) and a relatively high metal dispersibility. On the other hand, the Ni-Cu alloy has a significant effect on the adsorption and activation of CO2 at high temperature. NiM/EXVTM-SiO2 (M = Co, Cu, Fe) bimetallic catalysts was obtained by the incipient wetness impregnation method. Due to the synergistic effect between Ni and Cu, NiCu/EXVTM-SiO2 catalyst shows good performance in catalytic methane reforming.

Elucidating the non-linear effect of process parameters on hydrogen production by catalytic methane reforming: an artificial intelligence approach

This study focuses on the non-linear effect of gas hourly space velocity (GHSV), oxygen (O2) concentration in the feed, the reaction temperature, and the CH4/CO2 ratio on hydrogen production by catalytic methane dry reforming using artificial neural networks (ANN). Ten different ANN models were configured by varying the hidden neurons from 1 to 10. The various ANN model architecture was tested using 30 datasets. The ANN model with the topology of 4-9-2 resulted in the best performance with the sum of square error (SSE) of 0.076 and coefficient of determination (R2) greater than 0.9. The predicted hydrogen yield and the CH4 conversions by the optimized ANN model were in close agreement with the observed values obtained from the experimental runs. The level of importance analysis revealed that all the parameters significantly influenced the hydrogen yield and the CH4 conversion. However, the reaction temperature with the highest level of importance was adjudged the parameter with the highest level of influence on the methane dry reforming. The study demonstrated that ANN is a robust tool that can be employed to investigate predictive modeling and determine the level of importance of parameters on methane dry reforming.

Original Method to Predict and Monitor Carbon Deposition on Ni-Based Catalysts During Dry Reforming of Methane

Although the catalytic reforming of methane with carbon dioxide, also known as dry reforming, has recently attracted considerable attention due, the one hand, to the simultaneously utilization of two greenhouses with high environmental impact and, the other hand, to produce syngas with a lower H2/CO ratio than those available from steam reforming and partial oxidation of methane, which is preferred for the synthesis of valuable oxygenated chemicals and long-chain hydrocarbons, has not yet been commercialized. Low-cost Ni-based catalysts with high activity were developed. However, due to their major drawbacks, which are carbon formation and Ni particles sintering at the high temperatures requires by the endothermic reaction, their industrial applicability is limited. What is more, access to advanced characterization techniques is needed to monitor coke deposition and to assess the efficiency of the dry reforming process, access which can be challenging for small and on-site laboratories. The focus of this current study is on the development and testing of a simple carbon deposition prediction method, easily accessible, based on the comparison of the gas composition measured at the exit of the reactor with the theoretical one, calculated based on the process thermodynamics. Trustworthy results, confirmed by SEM and TGA/DSC measurements, were obtained when the method was applied for the monometallic, Ni/SBA-15, prepared by wet impregnation, and bimetallic, Ni-Co/SBA-15 and Ni-La/SBA-15 samples, prepared by impregnation but co-impregnation as well, with different metal loading. The dry reforming process was performed at four temperatures, 550, 600, 650 and 700°C, respectively.

Catalytic reforming of methane into synthesis-gas

Using θ-Al2O3 as a carrier and Ni and Co as active materials, a series of catalysts were prepared by traditional method of air impregnation on moisture capacity. Test the catalyst with XRD and other characterization methods. The performance of the methane dry reforming reaction was investigated on a fixed reactor. The optimal process conditions were: T = 700 and 900 °C, GHSV = 6000 h−1 and CH4: CO2: Ar = 1: 1: 1, 5%Ni-5%Co/θ-Al2O3 has the best activity and the smallest particle size.

Simulation of autothermal hydrogen-producing limestone calcination for calcium looping in turbulent fluidized bed reactors

This paper investigates the performance of combining limestone calcination with catalytic methane reforming and combustion in turbulent fluidized bed membrane reactors. The equilibrium performance of the process was evaluated using Aspen simulation, with a unique correlation to estimate the required gaseous feed composition for autothermal and complete sorbent regeneration at operating temperatures of 800–900 °C. A one-dimensional, isothermal, steady-state kinetic model is then employed to study the performance of the four-in-one (combustion + reforming + calcination + optional membrane separation) integrated process under turbulent fluidization conditions. The simulation results demonstrate the high potential of this novel sorbent regeneration technique for autothermal, rapid and hydrogen-producing limestone calcination. The performance is shown to depend strongly on the sorbent/total gas molar feed ratio, operating temperature, operating pressure and sorbent residence time.

Simulation of Limestone Calcination for Calcium Looping: Potential for Autothermal and Hydrogen-Producing Sorbent Regeneration

The combination of limestone calcination, catalytic methane reforming, and combustion in a membrane reactor is simulated as a possible means to achieve autothermal and hydrogen-producing sorbent re...

Comparison of ANFIS and ANN modeling for predicting the behavior of a catalytic methane reformer

Adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) were applied in modeling of methane mixed reforming in a packed bed catalytic reactor. These methods were developed by use of data collected from a methane reforming pilot plant using CO2 and steam and in process conditions near to MIDREX reforming plant in sponge Iron production. Different reaction temperatures from 700 to 1100 C with different values of carbon dioxide, steam, hydrogen, methane and carbon monoxide, were randomly selected and used to generate around 5000 data set of input- output data. Both networks achieve quite satisfying scientific results with acceptable deviations. However, it is hard to say which one is better as they have close output values but ANN marginally outperformed ANFIS in predicting the reaction outputs by varying the inputs. The prediction performances of these models are compared. The accuracies of the two models were evaluated in terms of square correlation coefficient (R2) and mean square error (MSE).

Compact solid oxide fuel cells and catalytic reformers based on microtubular membranes

AC heated oxygen-permeable microtubular membranes with the composition Ba0.5Sr0.5Co0.78W0.02Fe0.2O3-δ were used to provide catalytic reforming of methane into C2- hydrocarbons. The methane conversion degree about 60% and acetylene yield about 27% at 1200 °C was achieved. Microtubular solid oxide fuel cells based on gadolinium-doped ceria with perovskite-like cathode material composed of Ba0.5Sr0.5Co0.75Mo0.05Fe0.2O3-δ were prepared. The MT-SOFC demonstrates maximum power densities of 50, 100, 200 mW/cm2 at 550, 600, 650 °C, respectively with humidified H2 as fuel and ambient air as oxidant.

H2S poisoning of NiAl2O4/Al2O3‐YSZ catalyst during methane dry reforming

The objective of this work was to test resistance to hydrogen sulphide (H2S) of a recently‐patented nickel‐aluminum (Ni‐Al) spinel on Al2O3/YSZ ceramic support in catalytic reforming of methane (CH4). Previous studies showed that the catalyst is efficient for both steam reforming of complex hydrocarbons (diesel) and dry reforming of CH4. In the latter case, carbon formation was avoided for 275 h with a carbon dioxide (CO2)/CH4 ratio of 1.2. Catalytic activity was monitored at various temperatures and H2S concentrations (780–850 °C and 1.28–237 μL/L (ppmv) H2S). All tests were conducted at atmospheric pressure in a differential reactor setup. The other experimental conditions were: molar ratio 1 CO2/1 CH4/0.1 H2O, catalyst mass of 0.3 g, and gas hourly space velocity of 7000–8000 mLSTP/(gcata · h). Helium was used as the carrier gas for H2S. The NiAl2O4/Al2O3‐YSZ catalyst was loaded with nickel (Ni) 0.05 g/g (5 mass%), the Al2O3/YSZ mass ratio was 1/1, and YSZ was Y2O3‐stabilized ZrO2 (Y2O3 0.07 g/g (7 mass%)). The results showed the fastest deactivation at low temperatures and the highest H2S concentration. Catalyst activity could be partially recovered by stopping the H2S feed, and entirely recovered by calcining it at 900 °C in air. Essentially, YSZ had no effect on catalyst resistance to the presence of H2S. The catalyst gave results comparable to a commercial catalyst tested and reported in the literature.

An overview on dry reforming of methane: strategies to reduce carbonaceous deactivation of catalysts

Catalytic reforming of methane (CH4) with carbon dioxide (CO2), known as dry reforming of methane (DRM), produces synthesis gas, which is a mixture of hydrogen (H2) and carbon monoxide (CO).

Ni nanoparticles immobilized Ce-modified mesoporous silica via a novel sublimation-deposition strategy for catalytic reforming of methane with carbon dioxide

A kind of Ni nanoparticles (NPs) immobilized Ce-modified mesoporous silica was synthesized via a novel sublimation-deposition strategy and evaluated in catalytic reforming of methane with carbon dioxide. The as-prepared catalysts were characterized systematically to elucidate their morphological structure and surface properties. Small Ni NPs ranging from 2.1 nm to 4.3 nm have been successfully assembled in the mesoporous silica with a homogenous distribution. As compared with conventional Ni-impregnated catalysts, the catalysts exhibit more stable and near equilibrium conversion for CH4 and CO2 for 20 h at 750 °C with negligible carbon deposition. The confinement effect deriving from the mesoporous channels of silica support, as well as the high dispersion and reducibility of Ni NPs due to strong Ni–SiO2 interaction contribute to the enhanced coking- and sintering-resistance. Furthermore, the addition of ceria further improves the coke resistance, leading to the consistent catalytic performance of the catalysts in dry reforming of methane. We believe that the successful application of sublimation-deposition strategy can also play a role in the design of robust catalysts with excellent catalytic activity and durability for many other coking- and sintering-resistant reactions.

Numerical simulation of a structured catalytic methane reformer by DUO: The new computational interface for OpenFOAM® and DETCHEM™

The catalytic partial oxidation of methane over a honeycomb-structured Rh/Al2O3 coated catalyst is studied at a molar C/O ratio of unity and short-contact times experimentally and numerically. Axial species and temperature profiles inside the catalytic monolith are measured by a capillary sampling technique. A detailed numerical analysis of the flow, temperature and species concentration profiles is conducted using the new software tool DUO, which is an interface for the coupling of the computational tools OpenFOAM® and DETCHEM™. This interface enables the integration of detailed surface chemistry into OpenFOAM® and allows the time-efficient calculation of structured catalysts and other catalytic reactors with multiple combined fluid and solid regions including heterogeneous reactions. In comparison with experimental data, spatial profiles of species and temperature are analyzed. The thermal boundary conditions are shown to have a strong impact on reliable predictions. Even though the characteristics of the influence of radial heat loss on the conversion can be governed, the use of a radiation model is recommended.

Catalytic reforming of methane with CO2 over metal foam based monolithic catalysts

Solar reforming of natural gas has been considered as the promising conversion route of solar fuels with the concentrated solar heat. The present work focuses on investigating the catalytic reforming reaction over metal foam based monolithic catalysts. The 2 wt.%Ru/Al2O3/AISI 316 foam and 5 wt.%Ni/Al2O3/AISI 316 foam were prepared via the process of coating and impregnation. The catalytic properties of 5 wt.%Ni/Al2O3/AISI 316 foam and 2 wt.%Ru/Al2O3/AISI 316 foam for the methane reforming with carbon dioxide were tested in a continuous-flow fixed-bed reaction system. The results showed that the 2 wt.%Ru/Al2O3/AISI 316 foam exhibited higher catalytic activity and long-term stability for CO2 reforming of methane. The 316 stainless steel metal foam matrix had the very low catalytic performance for methane reforming with CO2 and the Al2O3 coating played a key role on the reactivity of the resulting catalysts.

Kinetic and structural requirements for a CO2 adsorbent in sorption enhanced catalytic reforming of methane – Part I: Reaction kinetics and sorbent capacity

This paper presents a fundamental model-based analysis for the applicability of integration of a highly active Rh/CeαZr1−αO2 catalyst with two candidate CO2 sorbents for pure H2 production in low temperature sorption-enhanced steam reforming of methane. K-promoted hydrotalcite and lithium zirconate solids are considered in the investigation as CO2 sorbents. The process is analyzed using multi-scale modeling levels of a heterogeneous particle-based model, a heterogeneous bulk-scale model, and a homogenous bulk-scale model. The presence of this active catalyst dictates strict requirements on the sorbent in terms of fast adsorption kinetics for an efficient process performance. The maximum CH4 conversion enhancement is determined to be a strong function of sorption kinetics. This enhancement is not affected by a higher sorbent capacity at slow adsorption kinetics. The process is studied using two fixed bed configurations of an integrated dual function particle and an admixture bed of catalyst/sorbent particles. Optimal operating conditions for the hydrotalcite-based system are identified to provide CH4 conversion of 98% with high H2 purity of 99.8% and low CO2 contamination (<250ppm). The lithium zirconate-based system can provide CH4 conversion and H2 purity of 99.9% at identical conditions. Based on the end application of H2 produced, the process can be tuned to feed gas turbine cycles, fuel cells, or petrochemical plants.

Effect of Pd on CH&lt;sub&gt;4&lt;/sub&gt; Reforming with CO&lt;sub&gt;2&lt;/sub&gt; Catalyzed by Ni over Mixed Titian –Alumina Support

The catalytic reforming of methane with carbon dioxide using Pd promoter on 1% Ni/20%TiO2-P25+80%α-Al2O3 was investigated. An experimental study was carried out using the catalyst prepared by impregnation method. The catalysts were dried at 120°C and calcined at 900°C. The reforming reactions were carried out using CO2/CH4/N2 feed ratio of 5/5/1, F/W=44 ml/min.gcat and reaction temperature of 700°C. The effect of nominal load of Pd ranging from 0.0 to 0.48 was studied by evaluating catalyst activity, stability, coke and (H2/CO) ratio. The prepared catalysts were tested in micro reactor at atmospheric pressure. The effluents were analyzed using an online gas chromatography equipped with a thermal conductivity detector. EDS and TGA for the fresh and spent catalysts were evaluated. Results indicate that the addition of small amounts of Pd is preferable in terms of activity and carbon deposition than higher Pd loading. For instance, 0.01%Pd gives a conversion of 78.4 for CH4 and 4.9% deactivation factor. While, 0.48%Pd gives a conversion of 75.6 for CH4 and 29.9% deactivation factor. Thus higher loading of Pd causes the catalyst to show poor performance with lower conversion and higher carbon formations. It can be concluded that Pd promoter has an optimal concentration with respect to the active metal of the catalyst beyond which the performance deteriorates.