كليدواژه :
آتش نشاني , پالايشگاه گاز ايلام , شبيه سازي هيدروليكي , WaterGEMS
چكيده فارسي :
شبيه سازي هيدروليكي خطوط انتقال و شبكه هاي توزيع آب آتش نشاني ابزار مناسبي براي ارزيابي آنها است. در اين تحقيق عملكرد شبكه آب آتش نشاني پالايشگاه گاز ايلام (رينگ مياني) با مطالعات ميداني و شبيه سازي هيدروليكي ارزيابي شد و نيازها و مشكلات اين شبكه شناسايي شد. شبكه آب آتش نشاني پالايشگاه به سه ناحيه يا رينگ بالايي، مياني و پايين تقسيم شده است و هر ناحيه وظيفه اطفاي حريق بخشي از محدوده پالايشگاه را بر عهده دارد. محاسبات هيدروليكي خط انتقال آب از منبع آب اصلي پالايشگاه به منبع آب رينگ مياني داراي شير كشويي در چهار حالت بهره برداري انجام گرفت. سناريوهاي مختلف آتش سوزي براي بررسي عملكرد شبكه آب آتش نشاني انجام گرفت. بحراني ترين سناريو، آتش سوزي در مخازن استوانه اي با سقف شناور است كه دبي مورد نياز جهت اطفاء حريق آن m3/h 1375 است. تحليل حساسيت نسبت به تغييرات ضريب زبري لوله ها و دبي مورد نياز در شبكه انجام گرفت. با افزايش20 درصدي زبري، فشار در رينگ 3/5 درصد كاهش يافت. در حالت افزايش دبي مورد نياز، فشار پمپاژ و دلوج به ترتيب 3/2 و 12/2 درصد كاهش يافت. بازديدهاي ميداني انجام گرفته نشان داد كه 20 درصد از شيرهاي آتش نشاني شبكه دچار خرابي و نشت هستند. بررسي ميداني عملكرد سيستم خنك كاري مخازن استوانه اي با روشن بودن يك و دو پمپ الكتريكي انجام گرديد. بررسي ميداني سيستم فوم مخازن استوانه اي با روشن بودن يك پمپ ديزل انجام گرديد. فشار مربوطه در حين مانور در ايستگاه پمپاژ رينگ مياني برابر با 12 بار ثبت شد و اين فشار بالا مي تواند باعث خرابي تجهيزات رينگ گردد.
چكيده لاتين :
Evaluation of Hydraulic Performance of Ilam Gas Refinery fire-fighting water network (middle ring) Abstracts Hydraulic simulation of conveyance lines and fire-fighting 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 fire-fighting 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 fire-fighting 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 middle-pumping station, which could cause a failure of the ring equipment. Keywords: Fire-fighting, 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 fire-fighting 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, shut-off 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 fire-fighting 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 middle-pumping 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.
