无磷缓蚀阻垢剂在天然气净化厂循环水系统中的应用

Application of phosphorus free corrosion and scale inhibitor in circulating water system of natural gas purification plant

目的探讨无磷缓蚀阻垢剂在天然气净化厂循环水系统中应用的适应性。方法以聚环氧琥珀酸和锌盐为主要原料研制了CT4-39B,采用室内旋转挂片腐蚀试验、静态阻垢试验、微观形貌观察等对CT4-39B的水质工况适应范围进行了评价,并在某保有水量规模为150 m^(3)的天然气净化厂循环水系统开展了现场应用。结果室内评价结果显示,在钙硬度为100~600 mg/L的水质工况范围内,碳钢腐蚀速率可控制到低于0.02 mm/a,静态阻垢率超过90%。现场应用也证实CT4-39B具有良好的效果,腐蚀速率远低于0.075 mm/a的控制指标。与此同时,循环水中以磷酸根计的总磷质量浓度由10.0 mg/L降至0.5 mg/L以下,起到了很好的节能减排效果。结论室内研究及现场试验结果均证实CT4-39B无磷药剂体系在钙硬度为100~600 mg/L的中低硬度水质中具有优异的效果,在保障循环水系统稳定运行的同时,可有效支撑净化厂的整体环保升级。

Objective The aim of this study is to explore the feasibility of phosphorus-free corrosion and scaling inhibitors in circulating water system of natural gas purification plant.Methods A phosphorus-free corrosion and scaling inhibitor was developed with polyepoxysuccinic acid and zinc salt as the main raw materials.Firstly,the water quality adaptability of the inhibitor was evaluated by means of indoor rotating coupon corrosion test,static scale inhibition test,and microscopic morphology observation,which were followed by field application in the circulating water system of a single natural gas purification plant with a capacity of 150 m^(3).Results The indoor evaluation results showed that the corrosion rate of carbon steel could be controlled below 0.02 mm/a and the static scale inhibition efficiency was observed to exceed 90%within the range of calcium hardness of 100-600 mg/L.The field application also confirmed that the CT4-39B has favorable effects since the corrosion rate is far lower than the control value of 0.075 mm/a.At the same time,the total phosphorus contents in circulating water calculated by phosphate radical reduced from 10 mg/L to less than 0.5 mg/L,which has a positive effect of energy conservation and emission reduction.Conclusions Both the indoor studies and field tests confirm that the phosphorus-free stable operation technology has excellent effects when facing the water with calcium hardness ranging from 100 mg/L to 600 mg/L,and can effectively support the overall environmental protection upgradation of the purification plant while ensuring the stable operation of the circulating water system.