مهندسی مکانیک مدرس

مهندسی مکانیک مدرس

شبیه‌سازی و مقایسه تاثیر گاز اکسیدکننده و مدل‌های مختلف فرآیند تبخیر مواد فرار در یک گازی‌ساز زغال‌سنگی نمونه ورود هم‌زمان

نوع مقاله : پژوهشی اصیل

نویسندگان
دانشکده مهندسی مکانیک، دانشگاه گیلان، رشت، ایران
چکیده
فناوری گازی‌سازی بخش مهمی از فناوری استفاده پاک از سوخت زغال‌سنگ به‌شمار می‌آید. توسعه هرچه بیشتر این فناوری نیازمند درک فرآیندها و اثرات متقابل جریان‌های گاز و ذرات سوخت جامد تزریق شده به درون محفظه گازی‌ساز است. در این مطالعه به شبیه‌سازی عددی یک گازی‌ساز زغال‌سنگی نمونه ورود هم‌زمان با استفاده از شرایط عملکردی آزمایشگاهی پرداخته شده است. واکنش‌ها و پارامترهای سینتیکی فرآیند گازی‌سازی با استفاده از داده‌های گازی‌سازی زغال‌سنگ در مقالات چاپ شده مشابه استخراج شده است. مقایسه نتایج حاصل از شبیه‌سازی با داده‌های آزمایشگاهی و دو مطالعه مشابه دیگر به‌خوبی صحت مدل توسعه یافته را تایید می‌کند. تمرکز این مطالعه بر دقت مدل‌های ارائه شده برای فرآیند تبخیر مواد فرار از سوخت و بررسی تاثیر تغییر اکسیدکننده از اکسیژن به هوا بر عملکرد گازی‌ساز است. ۴ مدل تبخیر مواد فرار شامل مدل‌های نفوذ شیمیایی، تک‌نرخی، کوبایاشی و نرخ ثابت بررسی شده است. روند تغییرات پیش‌بینی شده برای گونه‌ها در مدل‌های مختلف مشابه یکدیگر است و بسته به دقت هر مدل مقدار سینگاز تولیدی تا حدودی با یکدیگر متفاوت است. مدل‌های کوبایاشی و نرخ ثابت، نرخ تبخیر مواد فرار آزاد شده از سوخت را نسبت به دو مدل دیگر کمتر پیش‌بینی می‌کنند. نتایج به دست آمده از مدل نفوذ شیمیایی نسبت به دیگر مدل‌ها مطابقت بیشتری با داده‌های آزمایشگاهی دارد اما زمان محاسباتی بالاتری طلب می‌کند. استفاده از اکسیدکننده هوا به‌جای اکسیژن سبب کاهش غلظت سینگاز تولیدی و بنابراین کاهش راندمان گازی‌ساز می‌شود.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Simulation and Comparison of the Effect of Oxidizing Gas and Different Devolatilization Models in an Entrained-Flow Coal Gasifier

نویسندگان English

M.A. Yazdanpanah Jahromi
K. Atashkari
M. Kalteh
Mechanical Engineering Faculty, University of Guilan, Rasht, Iran
چکیده English

Gasification technology is an important part of clean coal technology. Further development of this technology requires understanding the processes and interactions of gas and solid fuel particles injected into the gasifier. In this study, a numerical simulation of an entrained flow coal gasifier has been investigated using experimental operating conditions. The reactions and kinetic parameters of the gasification process have been extracted using coal gasification data obtained from similar published papers. Comparison of the simulation results with experimental data and two other similar studies confirm the accuracy of the developed model. The focus of this study is on the accuracy of the models presented for the devolatilization process and the effect of the oxidizer change from oxygen to air on the gasifier performance. Four devolatilization models including chemical percolation devolatilization, single rate, Kobayashi and constant rate models have been investigated. The predicted trends of species changes are similar in different devolatilization models but the amount of produced syngas is somewhat different depending on the accuracy of each model. The Kobayashi and constant rate models predict the devolatilization rate lower than the other two models. The results obtained from the chemical percolation devolatilization model are more consistent with the experimental data compared to the other models but require higher computational times. The use of air oxidizing agents reduces the concentration of produced syngas rather than oxygen and hence reduces the gasifier efficiency.

کلیدواژه‌ها English

Gasification
Numerical simulation
Coal Fuel
Devolatilization Process
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