陕北某气田气液降压分离系统污水结垢原因分析及防垢方法研究

Scaling cause analysis and scaling prevention measures of gas-liquid depressurizing separation system of some gasfield in Northern Shaanxi

针对陕北某气田气液降压分离系统结垢严重的现象,通过分析站内污水水质、结垢产物组成、天然气组成、污水配伍性和运行工况等,找出结垢原因并提出相应的处理措施。分析结果表明:结垢产物主要为Ca CO3,污水中成垢离子含量高、污水不配伍、压力骤降引起CO2分压降低促进CaCO3形成是气液降压分离系统结垢的主要原因。提出将阻垢剂加药点移至计量分离器出口,投加100 mg/L的阻垢剂WT-225,防垢效果显著。

The causes leading to the serious scaling of the gas-liquid depressurizing separation system of some gasfield in Northern Shaanxi are found out by analyzing the wastewater quality,the composition of scaling product,the composition of natural gas,the compatibility among the wastewater of different sources and the running conditions of the system,and the corresponding scaling prevention measures are proposed. The analysis results show that: the main scaling product is CaC O3; the high concentration of scaling ion in water,water is not compatible,pressure decreases sharply in flash point liquid tank,easy to produce CaC O3scale; the main causes leading to the system scaling are high content of scaling ions in the wastewater,the incompatibility among the wastewater of different sources and the formation of CaC O3 scale caused by sharp reduction of CO2 partial pressure. It is proposed that the dosing position of scale inhibitor is moved to the outlet of metering separator,and the scale inhibitor WT-225 of 100 mg is added to the wastewater of a liter,which can effectively prevent the scaling of the system.