Safety research on gas well produced water storage tank based on Plackett-Burman design

Aiming at the severe problems of possibilities for flammable and explosive risks during the actual production procedure, the X-ray diffractometer, ion chromatography and GC/MS were used to detect and analyze solid impurities, inorganic impurities and organic impurities in the gas well produced water initially. Then the changing law of vapor-liquid phase equilibrium of the gas well produced water system with diverse impurities under different contents was explored by laboratory experiments using the Plackett-Burman design. The results showed that the impurities in the gas well produced water mainly include solid impurities such as Fe₃O₄, inorganic impurities such as K⁺, and organic impurities such as formic acid. The impurities could affect the gas-liquid phase equilibrium of gas well produced water to different degrees. Compared with the pure methanol-water system, the impact shows a certain positive deviation overall. Moreover, FeS, MgCO₃, K⁺, Ca²⁺, F^-, formic acid, n-decane, n-heptane, 1, 2, 4-trimethylbenzene and ethylcyclohexane among these impurities have significant influences on the molar fraction of methanol in vapor phase, among which ethylcyclohexane has the greatest effect followed by Ca²⁺, and FeS is the smallest. The research results could provide a scientific and reliable theoretical basis and data source for the safe operation of gas well produced water storage tanks, and a reference to the same types of equipment.