محاسبه سینتیک واکنش ریفرمینگ متان با بخار آب بر‎روی کاتالیزور بهینه Ni-Zn-Al

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده شیمی و مهندسی شیمی، دانشگاه صنعتی مالک اشتر، تهران، ایران

چکیده

در این پژوهش فرآیند ریفرمینگ متان با بخار آب با کاتالیزور Ni-Al-Zn مورد بررسی قرار گرفت. این فرآیند در صنعت در محدوده دمایی 900ºC-750 انجام می‎شود. به منظور کاهش دمای عملیاتی که از نظر اقتصادی و فرآیندی بسیار مهم است، کاتالیزور Ni-Al-Zn مورد بررسی قرار گرفت. این کاتالیزور از روش هم‎رسوبی ساخته شد. نتایج آنالیزهایXRD ، ICP و BET نحوه ساخت کاتالیست را تایید کردند. سپس این کاتالیست در فرآیند ریفرمینگ متان با بخار آب بررسی شد و مشخص گردید که درصد بهینه نیکل در کاتالیست 15% است. عملکرد این کاتالیزور در دمای 650ºC شبیه کاتالیزور صنعتی در دمای 750ºC در شرایط آزمایشگاهی است به‎طوری‎که در این دما، تبدیل متان نزدیک به 75% است. همچنین این کاتالیزور در دماهای بیش از 600ºC نسبت به رسوب کربن مقاوم است. پس از ارزیابی کاتالیست، آزمایش‎های سینتیک روی آن صورت گرفت. انرژی فعال‎سازی برای واکنش تبدیل متان به CO و H2، واکنش تبدیل آب- گاز و تبدیل متان به CO2 و H به‎ترتیب kJ/mol 4/219، kJ/mol 90/71 و kJ/mol 04/221 به‎دست آمد. برای واکنش‎های تبدیل متان انرژی فعال‎سازی کمتر از مقادیر کاتالیزور صنعتی به‎دست آمد که نشان‎دهنده عملکرد مناسب کاتالیزور در این فرآیند است. همچنین پارامترهای مربوط به جذب گازها روی کاتالیست از نظر ترمودینامیکی مورد ارزیابی قرار گرفت و تایید شد.
 

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Kinetic Study of Optimum Ni-Al-Zn Catalyst in the Steam Methane Reforming Reaction

نویسندگان [English]

  • Ali Saberimoghaddam
  • ALi Nozari
Department of Chemistry and Chemical Engineering, Faculty of Chemical Engineering, Malek Ashtar University of Technology (MUT), Tehran, Iran
چکیده [English]

In this study, steam methane reforming was investigated by using Ni-Al-Zn catalyst. This process carried out at 750-900 °C in the industrial plants. From the economical and operational point of view, the reduction of operational temperature is important. Therefore, the Ni-Al-Zn catalyst was studied to decrease the operational temperature. This catalyst was synthesized by coprecipitation method. The results of XRD, ICP, and BET revealed that catalyst were appropriately synthesized. Then, this catalyst was used in the steam methane reforming process and 15% nickel was obtained as optimum value. The performance of optimum catalyst at 650 °C was similar to industrial catalyst at 750 °C, so that the methane conversion was about 75 %. This catalyst showed high carbon resistance at temperatures above 600 °C. Kinetic study of optimum catalyst was performed. Moreover, the activation energy for reaction of methane to CO and H2, water gas shift and methane to CO2 and H2 were 219.4 kJ/mol, 71.90 kJ/mol, and 221.04 kJ/mol, respectively. The results of kinetic experiments on the synthesized catalyst showed that the activation energy for the first and third reactions of reforming (hydrogen production via methane and steam) was less than the activation energy on the industrial catalyst which reveals higher activity of the synthesized catalyst. Furthermore, the adsorption parameters in the kinetics equations were obtained and thermodynamically verified.
 

کلیدواژه‌ها [English]

  • Steam Methane Reforming
  • Ni-Al-Zn Catalyst
  • Kinetic Study
  • Methane Conversion
  • Activation Energy
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