شبیه‌سازی پدیدۀ رسوب‌گرفتگی در رآکتور پلی‌اتیلن سبک پتروشیمی کردستان

نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناس ارشد مهندسی شیمی، دانشگاه کردستان

2 دانشیار مهندسی شیمی، دانشگاه کردستان

چکیده

پلی‌اتیلن سبک بسپاری از خانوادۀ پلی‌اتیلن‌هاست که به‌طور عمده در صنعت پلاستیک کاربرد دارد؛ این بسپارها در فشارها و دماهای بالا با استفاده از واکنش رادیکالی تشکیل می‌شوند. پدیدۀ رسوب‌گرفتگی ‌ناشی از جداسازی فاز ترمودینامیکی بسپار و اتیلن است که این جداسازی فاز در منطقۀ دیوارۀ رآکتور لوله‌ای (نزدیک به جریان خنک‌کننده) رخ می‌دهد. رسوب‌گرفتگی باعث کاهش انتقال حرارت به سیال درون ژاکت رآکتور و موجب کاهش تولید و در موارد بحرانی باعث تجزیۀ خطرناک اتیلن می‌شود. هدف این پژوهش شبیه‌سازی پدیدۀ رسوب و تأثیرهای آن بر روی دما و فشار خروجی رآکتور بر پایۀ مسائل انتقال حرارت است. مدل ریاضی حل‌شده بر اساس معادلات انتقال حرارت شکل‌گرفته و برای محاسبۀ داده‌های تعادل فازی با توجه به فشار و دما از معادلات حالت SRK استفاده‌ شده است. در پایان با بهره‌گیری از شگرد دینامیک سیالات محاسباتی، داده‌های به‌دست‌آمده حل و شبیه‌سازی شد. نتایج به‌دست‌آمده بیانگر نحوۀ تأثیر مشخصات رسوب ایجادشده بر روی عملکرد حرارتی رآکتور است. مدل انجام‌شده در شرایط عملیاتی برای پلی‌اتیلن سبک با درجۀ H 2420 تحت لیسانس شرکت بازل انجام‌ شده است. بر اساس نتایج مدل‌سازی مشخص شد که با افزایش ضخامت رسوب از 1/0 تا 2/1 میلی‌متر، دمای خروجی رآکتور افزایش پیدا می‌کند؛ اما تأثیر چشمگیری بر میزان افت فشار درون رآکتور ندارد. هم‌چنین افزایش 10 درجه‌ای دمای واکنش باعث شد که درصد حجمی فاز دوم (رسوب) از 0.1833 به 0.1818 میلی‌متر کاهش داده شود.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Simulation of Fouling Phenomenon in Low Density Polyethylene Reactor in Kurdistan Petrochemical Company

نویسندگان [English]

  • S. Karimi 1
  • R. Beigzadeh 2
1 M. Sc. in Chemical Engineering, University of Kurdistan
2 Associate Professor of Chemical Engineering, University of Kurdistan
چکیده [English]

Low-density polyethylene is a subset of polyethylene that is mainly used in the plastics industry. These polymers are formed at high pressures and temperatures using a radical reaction. The fouling phenomenon is the result of the thermodynamic phase separation of polymer and ethylene. This phase separation occurs in the wall area (wall close to the cooling flow) of the tubular reactor, which reduces heat transfer to the reactor jacket, reducing production and in critical cases dangerous decomposition of ethylene. The purpose of this study is to simulate the phenomenon of fouling and its effects on the temperature and pressure of the reactor based on the heat transfer problems. The solved mathematical model is formed based on heat transfer equations to solve the computational fluid dynamics equations which are used to calculate the phase equilibrium data for pressure and temperature: The obtained results show that by increasing the thickness of the fouling, the heat transfer rate decreases. The operating model was used based on thelow-density polyethylene with a grade of 2420H. Based on the model, it was found that with increasing the thickness of fouling from 0.1 to 1.2 mm, the outlet temperature of the reactor increases, but does not have a significant effect on the pressure drop inside the reactor: Moreover,10 °C increase in reaction temperature caused the volume percentage of the second phase (fouling) is reduced from 0.1833 to 0.1818 mm.
 

کلیدواژه‌ها [English]

  • Low Density Polyethylene
  • Fouling
  • Computational Fluid Dynamics
  • Cooling Flow

مراجع

 

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مهندسی شیمی ایران
دوره 22، شماره 128 - شماره پیاپی 128
مرداد و شهریور 1402
صفحه 52-66

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