Guangdong Petrochemical has successfully solved the problem of high oil content in acidic water
Since the implementation of the key research plan for oil content in acidic water in March this year, the volume of light polluted oil sent out has reached 2,446.25 tons, a significant increase compared to before. The COD of purified water has dropped from exceeding the standard twice a month on average to zero. The impurity content of acidic gas has continued to decline, and the cleaning cycle of the reflux pump at the top of the stripping tower has been extended from once a month to 2.5 months. The steam consumption of the device has decreased, and energy consumption has continued to drop by nearly 10%. On May 19th, Guan Kai, the deputy manager of the Fifth Refining Department of Guangdong Petrochemical, said.
The acid water stripping unit of Guangdong Petrochemical mainly undertakes the recovery and treatment of acidic water produced by upstream production facilities. In late February this year, Zhao Sizhe, a trainee engineer from the Fifth Refining Department, found that the content of hydrogenated acidic water and oil in the system remained persistently high, reaching up to 3% at its peak, far exceeding the design index. High-oil and acidic water not only causes the COD of purified water to exceed the standard, posing a risk of impacting the sewage treatment system, but also increases the hydrocarbon content in the acidic gas, making it difficult to supply air to the sulfur recovery unit and causing fluctuations in the quality of sulfur products.
Facing the problem of persistently high oil content in acidic water, the Fifth Refining Department organized a special task force composed of Party members and technical backbones, and listed the centralized oil removal from acidic water tanks as a key research project. During the process of tackling the problem, they analyzed that the root cause of the issue lies in the complex state of oil-water mixture, the difficulty in separation, and the fact that the suspended black particles in the water further increased the difficulty of oil removal.
For this reason, they actively innovated and formulated a new plan. Under the premise of ensuring the stable operation of the sulfur recovery unit and the qualified quality of sulfur products, they recovered a large amount of waste oil from acidic water. To this end, they increased the frequency of oil removal from once per shift to twice and established a sight glass oil stain monitoring - dynamic adjustment mechanism. By tracking the DCS curve and on-site photos in real time, they flexibly adjusted the oil removal strategy. In addition, the team optimized the oil removal liquid level setting standard and extended the standing time to ensure the efficient separation of waste oil.
Up to now, the acid water stripping unit has been operating safely and stably for more than three months. A buffer zone has been set up between the downstream sulfur and wastewater reuse units and over 20 major upstream oil refining units, which has alleviated the impact of upstream fluctuations on downstream units without imposing harsh constraints on them, laying a solid foundation for the company's system's overall stability.