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天然气管道的投产包括清管、测径、试压、干燥、惰性气体惰化以及引入天然气等过程。其中,对天然气管道的干燥处理是海底输气管道投产前的重要工艺环节。干空气干燥工艺是海上输气管道干燥处理最安全、环保的方法,工程上干空气干燥工艺通常分为干空气干燥和吸水两个过程。分析论述了干空气干燥海底输气管道的原理,发现此过程是一个不稳定的吸水过程;应用质量守恒原理和相平衡理论建立了海底输气管道干空气干燥机理模型和吸水机理模型,并利用东方1—1气田平台间海底输气管道干燥工程实例验证了上述机理模型;还利用建立的模型对东方1－1外输海底管道采用的干空气干燥工艺的干燥过程进行了应用分析,提出了工艺设计与操作应考虑的因素。

AIR DRYING TECHNIQUES OF OFFSHORE GAS PIPELINES 1)

Pre-commissioning process of gas pipelines includes pipeline cleaning,callipering,pressure testing,drying,inert gas filling,and gas introducing,etc. Among them,the pipeline drying treatment is the major link of the pre-commissioning process of gas pipelines. Air-drying technique is the most secure and environment-protective method. The air-drying process commonly includes two parts,air drying and water soaking. The principle of drying pipeline with dry air is described. It is found that the process is an instable water soaking process. With the Mass Conservation and Phase Equilibrium theory, the models of air-drying mechanism and water soaking mechanism are established. The models are verified with the real case of drying offshore gas pipeline between platforms of Gas Field Dongfang 1-1. Also,with the models,the application of air-drying techniques of offshore gas pipeline in Gas Field Dongfang 1-1 is analyzed,and the factors that should be considered for process design and operation are proposed.