DOI: 10.5281/zenodo.7255178
title: Steam reforming processes using microchannel technology for conducting simultaneous endothermic and exothermic reactions

description: <strong>Steam reforming processes using microchannel technology for conducting simultaneous endothermic and exothermic reactions</strong> Junjie Chen Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com Many catalytic processes are known in which the catalyst and the reactants are not present in the same phase, that is, state of matter. These are known as heterogeneous catalytic reactions. They include reactions between gases or liquids or both at the surface of a solid catalyst. Since the surface is the place at which the reaction occurs, it generally is prepared in ways that produce large surface areas per unit of catalyst; finely divided metals, metal gauzes, metals incorporated into supporting matrices, and metallic films have all been used in modern heterogeneous catalysis. The metals themselves are used, or they are converted to oxides, sulfides, or halides. With solid catalysts, at least one of the reactants is chemisorbed (a portmanteau term for chemically adsorbed) by the catalyst. A catalyst is chosen that releases the products formed as readily as possible; otherwise, the products remain on the catalyst surface and act as poisons to the process. Chemisorption can occur over a wide temperature range, the most effective temperature for adsorption depending on the nature of the catalyst. Thus, hydrogen is chemisorbed readily by many metals even at liquid air temperatures. With a series of hydrogenation-dehydrogenation catalysts, for example, zinc oxide-chromic oxide, chemisorption of hydrogen often occurs above room temperature. Nitrogen is rapidly chemisorbed on synthetic ammonia-iron catalyst in the region at temperatures above 400 degrees Celsius. It has been shown that iron films chemisorb nitrogen even at liquid air temperatures, with additional chemisorption found above room temperatures. It follows from such considerations that whereas physical adsorptions, which parallel the ease of liquefaction of the adsorbed substance, occur spontaneously, chemisorption, which involves the making and breaking of chemical bonds, often requires activation energies (energy needed to initiate reactions) as do uncatalyzed chemical processes. To be efficient catalytically, a process must involve energies of activation for all the steps involved that, at their maxima, are less than those required for the uncatalyzed reaction. Streamwise distance (meter), Heterogeneous reaction rate along the length of the reactor (mole per square meter per second) 0 9.08258 0.00025 9.08623 0.0005 9.06858 0.00075 9.00579 0.001 8.90897 0.00125 8.80223 0.0015 8.71498 0.00175 8.6596 0.002 8.62783 0.00225 8.59661 0.0025 8.54384 0.00275 8.46052 0.003 8.35118 0.00325 8.23399 0.0035 8.13034 0.00375 8.05024 0.004 7.98947 0.00425 7.93422 0.0045 7.87164 0.00475 7.7959 0.005 7.70981 0.00525 7.62462 0.0055 7.55304 0.00575 7.50071 0.006 7.46372 0.00625 7.43144 0.0065 7.39358 0.00675 7.3462 0.007 7.29176 0.00725 7.23878 0.0075 7.19691 0.00775 7.16958 0.008 7.15358 0.00825 7.14021 0.0085 7.12094 0.00875 7.09265 0.009 7.05774 0.00925 7.02353 0.0095 6.99801 0.00975 6.98414 0.01 6.97862 0.01025 6.97401 0.0105 6.9631 0.01075 6.94354 0.011 6.91761 0.01125 6.89195 0.0115 6.87358 0.01175 6.86521 0.012 6.86398 0.01225 6.86277 0.0125 6.8552 0.01275 6.83935 0.013 6.81755 0.01325 6.79575 0.0135 6.78029 0.01375 6.77368 0.014 6.77343 0.01425 6.7728 0.0145 6.76616 0.01475 6.75146 0.015 6.73076 0.01525 6.70987 0.0155 6.6946 0.01575 6.68733 0.016 6.68571 0.01625 6.68358 0.0165 6.67524 0.01675 6.65921 0.017 6.6378 0.01725 6.61618 0.0175 6.59945 0.01775 6.59003 0.018 6.5862 0.01825 6.58161 0.0185 6.5713 0.01875 6.5542 0.019 6.53214 0.01925 6.50972 0.0195 6.49195 0.01975 6.48078 0.02 6.47405 0.02025 6.46635 0.0205 6.45304 0.02075 6.43348 0.021 6.40959 0.02125 6.38518 0.0215&nbs
description: Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China