Abstract




 
   

IJE TRANSACTIONS C: Aspects Vol. 28, No. 3 (March 2015) 330-337   

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  ULTRASONIC AND MICROWAVE PRETREATMENT FOR HYDROTHERMAL SYNTHESIS OF NANOSIZED SAPO-34 AND THEIR CATALYTIC PERFORMANCE IN MTO REACTION (RESEARCH NOTE)
 
H. Sharifi Pajaie and M. Taghizadeh
 
( Received: June 30, 2014 – Accepted: December 18, 2014 )
 
 

Abstract    In order to enhance the catalytic performance of SAPO-34 catalyst for the reaction of methanol to olefins (MTO), ultrasonic and microwave-assisted aging method were employed in static hydrothermal method to synthesize nano-sized SAPO-34. The effects of the application of this method on the chemical composition, morphology, surface area and total acidity of SAPO-34 were characterized by XRD, FE-SEM, nitrogen adsorption–desorption and NH3-TPD techniques. The catalytic performance of synthesized SAPO-34 was investigated for MTO reaction in a fixed-bed reactor under the same operating conditions (T = 450 °C, P =1 atm, and WHSV = 4 h−1). Comparing with the SAPO-34 synthesized with conventional hydrothermal method, sample synthesized with simultaneous use of US and MW-assisted aging methods possesses larger surface area and small crystal size and exhibits higher selectivity to light olefins (C˭2-C˭4) and longer lifetime.

 

Keywords    SAPO-34, Nanocatalysts, MTO reaction, Lifetime, Light olefins

 

چکیده    بمنظور افزایش عملکرد کاتالیستی SAPO-34 برای واکنش تبدیل متانول به اولفین (MTO)، از روشهای پیرسازی به کمک اولتراسونیک و مایکروویو برای سنتز SAPO-34 در ابعاد نانو بروش هیدروترمال استفاده گردید. تاثیر بکارگیری این روشها بر روی ترکیب شیمیایی، مورفولوژی، سطح ویژه و اسیدیته کل کاتالیست SAPO-34 بوسیله ی روش های XRD، FE-SEM، جذب و واجذب نیتروژن و NH3-TPD مورد بررسی قرار گرفت. عملکرد کاتالیستی کاتالیست های SAPO-34 سنتز شده برای فرآیند MTO در یک راکتور بستر ثابت و در شرایط عملیاتی یکسان (T=450 °C، WHSV = 4 h1 و در فشار اتمسفریک) مورد ارزیابی قرار گرفت. در مقایسه با کاتالیست SAPO-34 سنتز شده بروش هیدروترمال معمولی، نمونه ی سنتز شده با بکارگیری همزمان روشهای اولتراسونیک و مایکروویو سطح ویژه بزرگتر و اندازه کریستال کوچکتر و بهره ی بالاتر نسبت به اولفین های سبک (C˭2-C˭4) و طول عمر بیشتری را دارا می باشد.

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