جستجوی مقالات مرتبط با کلیدواژه « تبدیل » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

In recent decades, the integration of separation processes and reactions in a unit known as membrane reactor technology as a very powerful tool to improve the efficiency and economy in the chemical industry, has put promising procedures toward the researchers. The main objective of this study was to give a full report on the use of new technologies of membrane reactors in the chemical processes. In this study, first a variety of membrane reactors including polymeric, silica, metal, zeolite and perovskite membrane reactors has been investigated. Then, the application of this novel technology in various chemical processes, including processes of reforming, dehydrogenation, isomerization and decomposition of ammonia and CO2 and NOx has been analysed. Nowdays, due to the application of fossil fuels, environmental problems caused by greenhouse gas emissions is taken into consideration. Hence, the hydrogen as a clean fuel alternative is suggested. Literatures indicated that hydrogen can be achieved by using membrane reactor technology during the hydrocarbons reforming processes. On the one hand, regarding to hydrogen production purpose and its use in fuel cells, ammonia is considered as a suitable energy carrier for hydrogen production and its decomposition process, greenhouse gas emissions, involving CO and CO2, will not be obtained. On the other hand, by applying this technology in the analysis of nitrogen and carbon oxides, the harms caused from greenhouse gas emissions can be depleted.

Several varieties of processes are used for syngas production, but the methane H2O/CO2 reforming is the most important process and is commonly used. In this paper, at the first the common processes for syngas production are briefly studied and then using a computerized model, H2O/CO2 methane reforming reactions are thermodynamically studied. The effects of temperature, H2O/CH4 and CO2/CH4 ratios on product and process performance are studied and the results are shown as nomographs, which can be used for determination of the optimum process conditions for syngas and hydrogen production as well as reducing gas. To produce syngas with a H2/CO ratio equal to 1 (for FT process) the optimum H2O/CH4 is 2-2.5 and CO2/CH4 is 2.0 at high pressure and temperature. To produce hydrogen, H2O the optimum H2O/CH4 is 2.5-4 and CO2/CH4 is zero at temperature of 850 ºC and pressure of 20-30 bars.