- 學位論文
石化廠管道在線帶壓銲接修復之研究
Investigation of On-Service Welding Pipeline Repair for Petrochemicals Plant
摘要
管道輸送是最經濟最有效率的傳遞方式，在石油化學能源工業等己不可或缺，然而管道輸送中，受到各種因素的影響，出現腐蝕、失效、裂開、損害等情況，造成管線局部減薄、破損甚至發生洩漏事故，管線異常如不及時進行修復，輕則影響油氣產品的輸送、生產、供應，重則將造成起火、中毐、爆炸等災難事故發生，影響人們的生命財產安全，不可輕乎其嚴重性。以垂直整合的石化廠管道為例，概略介紹其管道損壞成因及其修復補強方法，為使管道的完整性提高可靠度及安全，簡介了管道在線修復方法，並深入研究在線帶壓修復的重點帶壓銲接技術，以解決管道正常輸送及供應下的修復方法。在線銲接修復指待修復管道內部輸送物質不須停輸，並於管壁上銲接補強，如果銲接熔池底部未熔金屬強度不能抵抗它所承受的管內壓應力時，就會發生『管壁銲穿』致使輸送中的管道發生洩漏，並與銲穿時的火花發生閃燃而引起火災、爆炸、失火等，危及銲接施工者的安全與管道所屬業主的風險。 由管壁銲穿的角度模擬管徑4”SS304不鏽鋼管3mm 10s管厚等級，以常壓、氣壓(空氣、氮氣)、液壓(水)為模擬管內壓力，配合銲接電流變數組採用SMAW與GTAW銲接方式，每組電流值組距10A到銲穿管壁為止，經試驗測得常壓銲穿入熱量為1.13KJ/mm，且常壓銲穿電流在120A時，管內壁有明顯的表面氧化銲穿現像。氣壓銲穿入熱量為1.41KJ/mm，且氣壓銲穿電流在150A時，管內壁才有明顯的表面氧化燒穿現像。液壓銲穿入熱量為2.36KJ/mm，且液壓銲穿電流於270A銲穿時管內體積因充滿水而使無氧條件，內壁均無明顯的氧化產生。由銲穿入熱量數據的了解，液壓的冷卻能力要大於氣壓，在相同入熱量的條件下，液壓管內散熱能力較快，導致內壁溫度相對於氣壓較低，因此液壓銲穿時的銲接入熱量要比氣壓要來的高，因此可得到銲穿入熱量的管制上限，作為下修安全值來管制銲接時的熱輸入，並繪製成帶壓銲接入熱量控製表，以確保執行在線帶壓修復作業時人員及管道輸送的安全，經過本文的研究可提供給管道業主及管理者、銲接人員、工程師提供具有參考價值的依據。
並列摘要
Burn-through by the wall angle simulated weld diameter 4 "SS304 stainless steel pipe thickness 3mm 10s level to normal pressure , air pressure ( air, nitrogen ) , hydraulic ( water ) to simulate the pressure inside the pipe , with the group using the SMAW welding current variables and GTAW welding , each current value of the group from 10A to weld of burn through the wall , as measured by normal pressure test weld heat-input is 1.13KJ/mm for burn-through the wall, and the welding current at 120A, the pipe inside wall welding surface is oxidation and darkly .Air pressure test welding heat-input is 1.41KJ/mm for burn-through the wall, when welding currwhen at 150A, the pipe inside wall welding surface is oxidation and darkly. Hydraulic test weld heat-input at 2.36KJ/mm, hydraulic welding current and wear due to the volume filled with water under pipe conditions , oxidation of the inner wall of no obvious wear at 270A welding pipe . penetration of heat from the welding data understanding , cooling capacity is greater than the hydraulic pressure in the under the same conditions of heat input , heat capacity and rapid hydraulic tube , resulting in a lower pressure relative to the inner wall temperature , so the welding heat input welding wear than when the hydraulic pressure to come high, so get penetration weld heat regulatory limit values as under the revised security control heat input welding , and draw with pressure welding heat input into the control table to ensure the implementation of security while online with pressure pipeline repair and operations personnel , through the study of this article is available to pipeline owners and managers, welders , engineers, provide the basis for a reference value