ارزیابی عملکرد هیدرولیکی شبکه آب آتش‌نشانی پالایشگاه گاز ایلام (رینگ میانی)

شبیه‌سازی هیدرولیکی خطوط انتقال و شبکه‌های توزیع آب آتش‌نشانی ابزار مناسبی برای ارزیابی آنها است. در این تحقیق عملکرد شبکه آب آتش‌نشانی پالایشگاه گاز ایلام (رینگ میانی) با مطالعات میدانی و شبیه‌سازی هیدرولیکی ارزیابی شد و نیازها و مشکلات این شبکه شناسایی شد. شبکه آب آتش نشانی پالایشگاه به سه ناحیه یا رینگ بالایی، میانی و پایین تقسیم شده است و هر ناحیه وظیفه اطفای حریق بخشی از محدوده پالایشگاه را بر عهده دارد. محاسبات هیدرولیکی خط انتقال آب از منبع آب اصلی پالایشگاه به منبع آب رینگ میانی دارای شیر کشویی در چهار حالت بهره‌برداری انجام گرفت. سناریوهای مختلف آتش‌سوزی برای بررسی عملکرد شبکه آب آتش‌نشانی انجام گرفت. بحرانی‌ترین سناریو، آتش‌سوزی در مخازن استوانه‌ای با سقف شناور است که دبی مورد نیاز جهت اطفاء حریق آن m3/h 1375 است. تحلیل حساسیت نسبت به تغییرات ضریب زبری لوله‌ها و دبی مورد نیاز در شبکه انجام گرفت. با افزایش20 درصدی زبری، فشار در رینگ 3.5 درصد کاهش یافت. در حالت افزایش دبی مورد نیاز، فشار پمپاژ و دلوج به ترتیب 3.2 و 12.2 درصد کاهش یافت. بازدیدهای میدانی انجام گرفته نشان داد که 20 درصد از شیرهای آتش‌نشانی شبکه دچار خرابی و نشت هستند. بررسی میدانی عملکرد سیستم خنک‌کاری مخازن استوانه‌ای با روشن بودن یک و دو پمپ الکتریکی انجام گردید. بررسی میدانی سیستم فوم مخازن استوانه‌ای با روشن بودن یک پمپ دیزل انجام گردید. فشار مربوطه در حین مانور در ایستگاه پمپاژ رینگ میانی برابر با 12 بار ثبت شد و این فشار بالا می‌تواند باعث خرابی تجهیزات رینگ گردد.

Evaluation of Hydraulic Performance of Ilam Gas Refinery fire-fighting water network (middle ring)

Evaluation of Hydraulic Performance of Ilam Gas Refinery firefighting water network (middle ring) Abstracts Hydraulic simulation of conveyance lines and firefighting distribution networks are considered appropriate tools for their assessment. In this research, Ilam gas refinery network (middle ring) was evaluated using field studies and hydraulic simulation software. The firefighting water network is divided into upper, middle and bottom rings. Each rings of the network are responsible for the one part of the refinery area. Hydraulic simulation of the water conveyance pipeline from the main reservoir to the middle ring reservoir were carried out in four modes of gate valve operation. Different fire scenarios were carried out to investigate the operation of firefighting network. The most critical scenario was the fires in floating roof tanks; with a flow rate of 1375 m3/h. Sensitivity analysis was performed on changes in the roughness coefficient of pipes and the required flow rate in the network. With an increase of roughness by 20%, the average pressure in the middle ring decreased by as much as 3.5%. In the case of increasing the required flow, the pumping pressure and deluge valve pressure drop by 3.2 and 12.2%, respectively. Field investigation showed that 20 percent of hydrants have problems and leaks. Field inspection of the cooling system operation of floating roof tanks was carried out with the activation of one and two electric pumps. The measured pressure gauge at the pumping station with one and two pumps is 11 and 12 bars, and these pressures are higher than 10 bar allowable pressure. The field inspection of tanks foam system was performed with the one of a diesel pump. The pressure gauge showed 12 bars at the middlepumping station, which could cause a failure of the ring equipment. Keywords: Firefighting, hydraulic simulation, WaterGEMS, Ilam gas refinery Introduction Fire water distribution networks consist of interconnected sets of reservoirs, pipes, pumps, hydrants, hose reels and valves that are responsible for the transfer and distribution of water with suitable pressure and quality for firefighting demands. Hydraulic simulation of conveyance lines and firefighting distribution networks are considered appropriate tools for their assessment. In this research, Ilam gas refinery fire water network (middle ring) was evaluated using field studies and hydraulic simulation software. Methodology Ilam gas refinery fire water network is divided into upper, middle and bottom rings. Each rings of the network are responsible for the one part of the refinery area. The maximum and minimum diameter of the distribution pipes is 14 inches and 6 inches, respectively. Polyethylene pipes have a working pressure of 16 bars. The maximum allowable velocity in the pipes is 3.5 m /s. At the refinery site, several centrifugal pumps have been used to supply pressure during firefighting, maintaining a pressure of 10 bar in the main ring. The total number of hydrants, shutoff valves and hose reels are 170, 147 and 76, respectively. WaterGEMS hydraulic software was used to simulate Ilam gas refinery fire water network. Results and discussion Different fire scenarios were carried out to investigate the operation of firefighting network. The most critical scenario was the fires in floating roof tanks; with a flow rate of 1375 m3/h. Hydraulic simulation of the water conveyance pipeline from the main reservoir to the middle ring reservoir were carried out in four modes of gate valve operation. Field investigation showed that 20 percent of hydrants have problems and leaks. Field inspection of the cooling system operation of floating roof tanks was carried out with the activation of one and two electric pumps. The measured pressure gauge at the pumping station with one and two pumps is 11 and 12 bars, and these pressures are higher than 10 bar allowable pressure. The field inspection of tanks foam system was performed with the one of a diesel pump. The pressure gauge showed 12 bars at the middlepumping station, which could cause a failure of the ring equipment. Conclusion In this research, the middle ring of the fire water network of Ilam gas refinery was tested and evaluated using the WaterGEMS hydraulic simulation software. Different scenarios related to this ring, which included the simultaneous operation of several hydrants and deluge valve in different areas, were simulated. Sensitivity analysis was performed on changes in the roughness coefficient of pipes and the required flow rate in the network. With an increase of roughness by 20%, the average pressure in the middle ring decreased by as much as 3.5%. In the case of increasing the required flow, the pumping pressure and deluge valve pressure drop by 3.2 and 12.2%, respectively. The results of the study indicate the proper operation of the firefighting water network, but in some cases the pressure generated at the pumping station is higher than the recommended values in the design, which in the long period could result in inappropriate performance.