بررسي آزمايشگاهي اثر خواص شيمي سطح گرافن بر فرايند تشكيل هيدرات متان و ميزان ذخيره سازي و پايداري آن

Estimation of greenhouse gas emissions in two refineries of Hasheminejad and Fajr Jam and providing operational solutions to reduce emissions

در اين تحقيق فرايند تشكيل هيدرات متان در حضور گرافن و گرافن اكسيد بررسي شد. بطوريكه ابتدا نانوصفحات گرافني توسط فرايند CVD بر روي بستر مس رشد داده و سنتز شد و با آناليزهاي XRD، FTIR و AFM ساختار آن مورد مطالعه قرار گرفت. سپس نانوسيالات پايدار حاوي گرافن و گرافن اكسيد شده با غلظت 1% وزني تهيه شده و در فرايند تشكيل هيدرات گازي در psig 1000 و دماي C 4 استفاده شد. به طوريكه نانوسيال حاوي گرافن/سورفكتنت ضمن كاهش زمان القا و انحلال به ترتيب تا %0/46 و %9/60 نسبت به نمونه آب خالص، توانسته ميزان ذخيره سازي را تا %7/56 افزايش دهد. اين امر بدليل افزايش 40 برابري انحلال اوليه متان در نانوسيال نسبت به آب بوده كه اين امر حاصل از كاهش مقاومت انتقال جرم در اثر حضور سورفكتنت و همچنين وجود سايتهاي فعال ناهمگن بيشتر جهت هسته زايي مي‌باشد. همچنين مشاهده شد علي رغم اينكه پايداري هيدرات هاي تشكيل شده در حضور گرافن كمتر از گرافن اكسيد است، اما بعد از رسيدن به پايداري، ميزان متان ذخيره شده در هيدرات گرافن از اين مقدار براي نمونه شاهد 9/34 حجم بيشتر است.

Nowadays, natural gas refineries have been developed to purify natural gas and optimize the extractive gas properties of gas wells for various uses, such as home use. Each gas refinery is composed of a set of process units, each of which can be a factor in the emission of greenhouse gases into the environment. Therefore, the purpose of this paper is to first study and estimates the greenhouse gas emissions of the process units in the two refineries of Shahid Hasheminejad and Fajr Jam and then provides solutions to improve performance and reduce carbon dioxide emissions in these refineries. Generally, greenhouse gas emission sources are divided into three sections: combustion, process and fugitive emissions. In the combustion section, four mass balance methods (based on the amount and composition of fuel), stack outlet gas analysis method, stack outlet gas analysis method and general propagation coefficient method have been used for both refineries. Comparison of the results of these four methods for boilers in these two refineries shows that the mass balance method will result in more accurate results in calculating the CO2 emission and emission factor for the calculation of the CH4 emission. Also, the fugitive emission related to equipment leakage of wastewater treatment process related to these two refineries has been estimated. The results of the estimation of greenhouse gas emissions in these two refineries show that the flaring of gases, carbon dioxide in the raw gas entering the refinery and fuel consumption in the energy conversion equipment are three main sources of greenhouse gas emissions. Therefore, 11 projects to improve the efficiency and reduce carbon dioxide emissions in these two refineries have been presented around the flaring reduction, improving energy efficiency (in all three sectors of production, transmission and consumption), and CO2 capture from exhaust gases from the stack of furnace.