مدل‌سازی فرآیند تغلیظ چند مرحله‌ای اجباری شورابه

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد دانشکده ی مهندسی مکانیک دانشگاه گیلان

2 گیلان*مهندسی مکانیک

چکیده

تغلیظ شورابه بدون تخلیۀ پساب، فرآیندی جامع از نظر شبیه‌سازی عملکرد است و نقش موثری در کاهش آلودگی زیست محیطی پساب خروجی از آب شیرین‌کن‌ها دارد. در پژوهش حاضر معادلات حاکم بر اجزای تغلیظ‌‌کننده‌ی لایه ریزان چند مرحله‌ای شورابه، تحت جریان جابجایی اجباری، تغذیۀ پیشرو، تعداد مراحل دلخواه و فشرده‌سازی بخار حرارتی در نرم‌افزار متلب مدل‌سازی شده است. نتایج مدل‌سازی ترمودینامیکی تغلیظ‌کننده‌ی دو مرحله‌ای نشان داد که از ton/hr 6/25 پساب با غلظت  ppm90000،ton/hr  5 آب شیرین و ton/hr 1/25 شورابه با غلظت ppm450000 حاصل شده است. نسبت بازده‌ی خروجی این واحد 2/63 و سطح مخصوص انتقال حرارت   74/3 است. همچنین با مدل‌سازی ترموهیدرولیکی، جهت کنترل رسوب و با افت فشار و سرعت جریان مجاز، به ازای طول‌ها، قطر‌ها و گذر‌های مختلف لوله‌ها، سطح انتقال حرارت و تعداد لوله‌های تبخیرکنندۀ هر مرحله محاسبه شده است. در انتها تأثیر پارامترهای طراحی بر بازده و سطح مخصوص انتقال حرارت بررسی شد. مشاهده شد که تعداد مراحل، دمای پساب تغذیه و دمای بخار راه‌انداز، سه پارامتر مهم در طراحی فرآیند است. افزودن یک مرحله، موجب افزایش 17 درصدی بازده و 23/5 درصدی سطح مخصوص انتقال حرارت، افزایش 1 درجه دمای خوراک باعث افزایش2/5 درصدی سطح مخصوص انتقال حرارت و افزودن 1 درجه دمای بخار راه‌انداز، سبب کاهش 3 درصدی سطح مخصوص انتقال حرارت شده در حالی که اثر این دو پارامتر بر بازده ناچیز است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Simulation of a Forced Multiple Effect Brine Concentration Process

نویسندگان [English]

  • Abbas Forouzi Feshalami 1
  • Ramin Kouhikamali 2
1 MSc. Student of Mechanical Engineering at Guilan University
2 Faculty of Mechanical Engineering, University of Guilan
چکیده [English]

Brine Concentration is a comprehensive process and has an effective role in reducing environmental pollution due to desalination plant wastewater. In this study, the equations, for feed-forward forced convective falling film brine concentrators, with the desired number of effects and thermal vapor compression have been solved by MATLAB code. Thermodynamic modeling results of a two stage brine concentrator represented that 6.25 ton/hr feed with 90000 ppm concentration produces 5 ton/hr fresh water and 1.25 ton/hr wastewater with 450000 ppm concentration. The gained output ratio of plant is 2.63 and the specific heat transfer area is 74.3 m2s/kg. Also, by thermohydraulic modeling, to control the sediment rate with the limitations of allowable pressure drop and stream velocity in different tube lengths and diameters and evaporator number of passes, heat transfer area and the number of tubes have been calculated. Finally, the effects of design variables on gained output ratio and specific heat transfer area are investigated. The results represented that effects number, feed, and driving steam temperature are the three most important variables since increasing the effects number causes a 17% increase in gained output ratio and 23.5% increase in the specific heat transfer area. Increasing 1 ֯C in feed and motive vapor temperature lead to a 2.5% increase and 3% decrease in the specific heat transfer area. But these two don’t have any effect on gained output ratio.

کلیدواژه‌ها [English]

  • Brine concentrator unit
  • Falling film evaporator
  • Thermodynamic and thermohydraulic design
  • Forced convective flow
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