Abstract:

The wet gas gathering pipelines will produce natural gas hydrate with the condition of high pressure and low temperature, which may cause blockage of pipelines or failure of key control equipment. Adding alcohols Thermodynamic?Inhibitor(THI) is one of the feasible proposals to prevent hydrate formation. If the amount of THI is poured excessive, the costs of procurement, transportation, storage and water treatment will increase in large quantities. Therefore, it is significant to determine the minimum dosage of THI based on a reasonable safety margin. Calculation of THI injection dosage based on empirical formula method and phase equilibrium software, without considering the effect of flow. In this paper, a method coupling of phase equilibrium and flow was used to optimize the injection dosage of THI. Based on the OLGA component tracking model, the temperature, pressure and THI concentration along the line are tracked, and then the THI dosage was predicted more accurately. Taking the gas gathering pipeline of land and submarine as an example, different calculation methods were compared. The results show that the new method can reduce the THI consumption by more than 10%.

Key words: Hydrate, Thermodynamic inhibitor, Component tracking, Injection dosage

摘要：

在高压低温的输送条件下，湿气集输管道中会有天然气水合物生成，而生成的水合物可能会导致管道堵塞或关键控制设备失灵等诸多风险。加注醇类水合物热力学抑制剂（THI），是预防湿气管道生成水合物的方法之一。若THI注入量过大，则不仅会增加采购、运输和储存成本，而且还会增加水处理成本。因此，在一定安全裕度的基础上，确定THI的最小注入量至关重要。基于经验公式法和相平衡软件的THI注入量的计算，不考虑流动的影响。为优化THI注入量，采用相平衡与流动耦合计算法，基于OLGA组分跟踪模型，对沿线的温度、压力以及THI质量分数进行了跟踪，以期较为准确地预测THI注入量。以陆地气田气和海底油田伴生气集输管道为例，对不同计算方法进行了对比。结果表明，相平衡与流动耦合计算法可减少THI注入量10%以上。

关键词: 水合物, 热力学抑制剂, 组分跟踪, 注入量