مهندسی مکانیک مدرس

مهندسی مکانیک مدرس

شبیه‌سازی و تعیین نقطه بهینه عملکرد یک گازی‌ساز رو به پایین با در نظر گیری تولید آلاینده‌ها

نویسندگان
1 دانشجوی دکتری
2 استاد دانشگاه گیلان
3 دانشگاه گیلان
چکیده
استفاده از زیست‌توده‌ها به‌روش گازی‌سازی به‌منظور تولید زیست‌سوخت و کاهش اثرات مخرب زیست‌محیطی سوخت‌های فسیلی در سال‌های اخیر مورد توجه بسیاری از محققان قرار گرفته است. در مطالعه حاضر از روش دینامیک سیالات محاسباتی به منظور پیش‌بینی فرآیند گازی‌سازی، درون یک گازی‌ساز رو به پایین استفاده شده است. بررسی مطالعات گذشته نشان می‌دهد که علی‌رغم انجام پژوهش‌های بسیار توسط محققان مختلف به منظور بیشینه‌سازی راندمان فرآیند گازی‌سازی، تاکنون مطالعه‌ای به منظور کمینه‌سازی میزان نشر آلاینده‌های حاصل از این فرآیند به‌عنوان یکی دیگر از اهداف مهم طراحی، انجام نگرفته است. بنابراین در این مطالعه، تاثیر تغییر نسبت هم‌ارزی به‌عنوان متغیر طراحی روی راندمان گازی‌ساز و همچنین میزان آلاینده تولید شده به صورت هم‌زمان مورد بررسی قرار گرفته است. همچنین در این مطالعه نسبت‌های مولی CO/CO2 و H2/H2O به‌عنوان یکی دیگر از عوامل موثر در انتخاب نقطه بهینه فرآیند در نظر گرفته شده است. به منظور بررسی صحت نتایج، داده‌های حاصل از شبیه‌سازی با نتایج آزمایشگاهی و مطالعه عددی پیشین، مقایسه شده و تطابق خوبی از مقایسه آن‌ها مشاهده شده است. نتایج به‌دست آمده از مطالعه حاضر نشان می‌دهد در نسبت هم‌ارزی0.64 نرخ تولید اکسیدهای نیتروژن به نسبت راندمان گاز سرد با در نظر داشتن بیشینه تولید نسبت‌های مولی CO/CO2 و H2/H2O دارای مقدار بهینه بوده و این نقطه بهینه‌ترین نقطه تحت شرایط کاری فرآیند گازی‌سازی می‌باشد.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Numerical simulation and optimum operational point determination of a downdraft gasfier regarding pollutant emissions

نویسندگان English

ali bahari 1
javad mahmoudimehr 3
1 Department of Mechanical EngineeringFaculty of EngineeringUniversity of GuilanP.O.Box 3756, Rasht, Iran.
3 Department of Mechanical EngineeringFaculty of EngineeringUniversity of GuilanP.O.Box 3756, Rasht, Iran.
چکیده English

The use of biomass by means of gasification to produce bio fuels and reducing the environmental impact of fossil fuels has been the focus of many researchers in recent years. In the present study, the computational fluid dynamics method is used to predict the process of gasification inside a downdraft gasifier. Recent studies have shown that although many studies have been carried out by various researchers to maximize the cold gas efficiency in the gasification process, so far, no study has been done to minimize the emission of pollutants as one of the other important design parameters along with the increase of cold gas efficiency. So, in this study, the effect of changing the equivalence ratio as design variable on the gasification efficiency as well as the amount of pollutant produced simultaneously is investigated. Also, in this study, CO/CO2 and H2 /H2O molar ratios are considered as another objective function in selecting the optimal process point. In order to verify the validity of the results, the simulation data was compared with the experimental results and the previous numerical study, and a good agreement was shown between their comparison. The results of this study show that in the ratio of 0.64, the rate of production of nitrogen oxides relative to cold gas efficiency is optimal considering the maximum production of CO/CO2 and H2/H2O molar ratios . This point is the optimal point. Under the working conditions of the gasification process.

کلیدواژه‌ها English

Gasification
Syngas production
Downdraft gasifier
Numerical simulation
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