Catalytic Reforming

In present study experimental and mathematical model have been carried out to describe the reaction kinetics of catalytic reforming process using Iraqi heavy naphtha as a feedstock for the process. Two types of catalysts were prepared (Pt-Ir-Sn/AL 2 O 3 and Pt-Ir/AL 2 O 3) supported on γ-AL 2 O 3. The main three described reforming reactions were investigated (dehydrogenation, hydrocracking, and dehydrocyclization) to characterize catalysts performance in term of activity and selectivity. The performance of catalysts were investigated under the following operating condition: reaction temperature range of 480-510˚C, weight hour space velocity range of 1-2hr-1 , pressure at 6 atm, and hydrogen to hydrocarbon ratio of 4:1. The results show higher conversion of Iraqi heavy naphtha components (i.e., Paraffins and Naphthenes) with higher temperatures whereas; weight hourly space velocity has shown negative impact on conversion (i.e., higher WHSV shows lower conversion). In general, it was noted that the yields of aromatics and light components are increased for both types of catalysts (Pt-Ir-Sn/AL 2 O 3 and Pt-Ir/AL 2 O 3) under the same operating conditions. Results of tri-metal catalyst better than bi-metal catalyst. A comprehensive mathematical model and simulation was developed in the present work to describe the reaction kinetics of reforming reactions. The model predicts the concentration, conversion, and temperature profile with time and axial direction of the reactor. The comparison between experimental and simulation results of the concentrations of (Paraffin's, Naphthenes, and Aromatics), and temperature showed a good agreement with a deviation confined 19.50%.

Addition of a calcium-based CO2 acceptor to commercial steam methane reforming catalyst permits the production of 95+% H2 in a single-step process. The combined reforming, shift, and CO2 separation reactions have been studied using a laboratory-scale fixed-bed reactor as a function of temperature, steam-to-methane ratio, acceptor-to-catalyst ratio, feed gas flow rate, and methane content of the feed gas. The combined reactions were sufficiently rapid above 550°C that equilibrium was closely approached at all reaction conditions studied. The H2 content of the product gas was relatively independent of temperature with the primary impurity at lower temperatures being CH4. Higher temperatures resulted in increased CH4 conversion but decreased carbon oxide removal leaving CO and CO2 as the primary impurities. Potential advantages of the single-step process, in addition to reducing the number of processing steps, include improved energy efficiency, elimination of the need for shift catalysts, and reduction in the temperature of the primary reactor by 150–200°C. Key unanswered problems involving the single-step process include continuous separation of catalyst and acceptor and the durability of the acceptor for multiple cycle operation.

Performance of a catalytic plate reactor coated with different patterns of distributed layers of reforming and combustion catalysts is investigated for the endothermic methane steam reforming (MSR) coupled with the exothermic methane combustion to produce hydrogen. To simulate MSR, an experimentally validated surface microkinetic model for a nickel-based catalyst is implemented in reforming flow channels. Required thermal energy to the MSR sites is supplied by catalytic and gas-phase methane combustion (MC) carried out in the neighbouring parallel flow channels. To simulate combustion reactions, a reduced surface microkinetic model for the catalytic MC and power rate model for the gas-phase MC are implemented in combustion flow channels. The study considers two-dimensional domains for the coating layers of reforming and combustion catalysts and identifies the internal-diffusion limitations for the reforming-catalyst coating thicker than 50 μm and for the combustion-catalyst coating thicker than 5 μm. Results obtained for different patterns of distributed coatings of reforming and combustion-catalysts are evaluated against the results obtained for conventional continuous coating layers by comparing temperature distribution, conversion, yield, selectivity, H 2 /CO ratio, efficiency, effectiveness-factor and plate-thickness. The study finds that by optimizing the distributed coating layers of the combustion-catalyst not only improves the utilization of both the catalysts and hydrogen production by 5% but also reduces the maximum plate temperature and axial thermal gradients along with 74% less combustion-catalyst compared to the continuous coating design. The study also finds that optimized distributed coating layers of both reforming and combustion catalysts predicts the similar methane conversion and hydrogen production as with the continuous coating layers for the same inlet molar feed rate but with 28% less reforming-catalyst and 74% less combustion-catalyst. Further, the study reports that the influence of distributed coatings of reforming and combustion catalysts is more pronounced in improving the performance of a catalytic plate reactor designed with relatively thick plate.

The paper reviews catalytic naphtha reforming, a process that has completed 50 y of existence and has improved the quality of human life globally. Also examines in detail are the historical background of reforming, reaction chemistry, reaction thermodynamics, process details, process variables, commercial processes, and future outlook. Recent environmental regulations have completely re-drawn the objectives of reforming and have even questioned its relevance. Attempts are also made to explain, in brief, the new challenges faced by reforming.

The addition of promoters to Pt/ZrO2 catalysts for the dry reforming of CH4 at 800°C has been investigated. It has been previously proposed that the ZrO2 aids in the dissociation of CO2, which helps to remove carbon that is deposited on the metal during the decomposition of CH4. The results of this study support this idea and show that the

The addition of promoters to Pt/ZrO2 catalysts for the dry reforming of CH4 at 800°C has been investigated. It has been previously proposed that the ZrO2 aids in the dissociation of CO2, which helps to remove carbon that is deposited on the metal during the decomposition of CH4. The results of this study support this idea and show that the

The paper reviews catalytic naphtha reforming, a process that has completed 50 y of existence and has improved the quality of human life globally. Also examines in detail are the historical background of reforming, reaction chemistry, reaction thermodynamics, process details, process variables, commercial processes, and future outlook. Recent environmental regulations have completely re-drawn the objectives of reforming and have even questioned its relevance. Attempts are also made to explain, in brief, the new challenges faced by reforming.

Possibility of hydrogen production from biogas using hot slag has been studied, in which decomposition rate of CO2–CH4 in a packed bed of granulated slag was measured at constant flow-rate and pressure. The molten slag, discharged at high temperature over ...

In present study experimental and mathematical model have been carried out to describe the reaction kinetics of catalytic reforming process using Iraqi heavy naphtha as a feedstock for the process. Two types of catalysts were prepared (Pt-Ir-Sn/AL 2 O 3 and Pt-Ir/AL 2 O 3) supported on γ-AL 2 O 3. The main three described reforming reactions were investigated (dehydrogenation, hydrocracking, and dehydrocyclization) to characterize catalysts performance in term of activity and selectivity. The performance of catalysts were investigated under the following operating condition: reaction temperature range of 480-510˚C, weight hour space velocity range of 1-2hr-1 , pressure at 6 atm, and hydrogen to hydrocarbon ratio of 4:1. The results show higher conversion of Iraqi heavy naphtha components (i.e., Paraffins and Naphthenes) with higher temperatures whereas; weight hourly space velocity has shown negative impact on conversion (i.e., higher WHSV shows lower conversion). In general, it was...

Novel Co (10%) catalysts supported on ZnO and promoted with Fe and Mn (1%) were synthesized and characterized by high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), X-ray diffraction (XRD) and X-ray ...