Objective  PESA and terpolymer were used as the primary raw materials for formulation screening in the research and development process of phosphorus-free corrosion and scale inhibitors.

Methods  The adaptability of phosphorus-free corrosion and scale inhibitors were evaluated and studied through the corrosion test and static scale inhibition tests.

Results  It was further applied to the circulating water system of a natural gas purification plant in Sichuan and Chongqing. Through field monitoring, the non-phosphorus corrosion and scale inhibitor achieved good corrosion and scale inhibition effect, and the corrosion rate was controlled below 0.075 mm/a. Meanwhile, the bacteria numbers in circulating water were counted before and after the test. The results showed a trend of continuous decrease, and the eutrophication degree of water was reduced, indicating that the phosphorus-free formula had a positive effect on the bacterial control of the system.

Conclusion  The laboratory study and field test results confirm that the screened corrosion and scale inhibitor system has excellent effect in water with medium and low levels of hardness and can guarantee the stable operation of the circulating water system in natural gas purification plant.