Jiangsu Haifa Machinery Manufacturing Co., Ltd.

The acetonitrile wastewater pump in the acrylonitrile unit of Jilin Petrochemical Company originally used a magnetic drive pump to transport the process medium. However, during long-term operation, frequent equipment failures occurred, severely impacting the stable operation and production continuity of the unit. To address issues such as high failure rates and high maintenance costs, the company implemented a technical transformation of the acetonitrile wastewater pump, replacing the magnetic drive pump with a centrifugal pump, achieving favorable operational results. An analysis of the failures revealed that the magnetic drive pump exhibited significant adaptability issues under these working conditions. First, the acetonitrile wastewater medium itself has a tendency to polymerize, easily forming polymers and deposits during transport, leading to frequent clogging of the pump inlet filter. When the filter becomes clogged, the pump inlet flow is insufficient, affecting the internal circulation cooling and lubrication system of the magnetic drive pump. Second, the sliding bearings of the magnetic drive pump adopt a medium self-lubricating structure, where bearing cooling and lubrication rely entirely on the transported medium. Once inlet clogging, flow interruption, or low-flow operation occurs, the sliding bearings quickly lose lubrication conditions, resulting in dry running. Due to the relatively enclosed internal space of the magnetic drive pump, heat cannot be dissipated in time, potentially leading to bearing burnout, rotor seizure, or even high-temperature demagnetization of the internal magnetic components within a short period. Additionally, polymers in the acetonitrile wastewater easily clog the internal circulation channels and flushing passages of the magnetic drive pump, further reducing cooling efficiency and creating a vicious cycle. After prolonged operation, the equipment frequently experienced failures such as increased vibration, abnormal current, reduced flow, and bearing damage, with significantly higher maintenance frequency and persistently high operating costs. In contrast, the retrofitted mechanical seal centrifugal pump demonstrates stronger adaptability to short-term flow fluctuations and medium impurities, with a relatively simpler internal structure that does not rely on the medium for bearing lubrication, effectively reducing the impact of the polymerizing medium on equipment operation. After the transformation, the operational stability of the unit significantly improved, saving 208,000 yuan in annual maintenance costs, achieving the dual goals of safe production and cost reduction with increased efficiency. This transformation case also indicates that in complex chemical working conditions, pump selection must fully consider medium characteristics, operating conditions, and equipment structural principles to avoid long-term operational risks caused by mismatches between conditions and equipment. Jiangsu Haifa Machinery Manufacturing Co., Ltd. was restructured from Jiangsu Ligong Group Co.,., formerly the Jingjiang Stainless Steel Pump and Valve Factory of the Iron and Steel Research Institute under the Ministry of Metallurgical Industry, established in 1958. It primarily produces API610 chemical process pumps—OH1, OH2, OH3, OH4 pumps; BB1, BB2,3, BB4,5 multistage pumps; VS1,4, VS5, VS6 barrel casing pumps; HES-type chemical process pumps; chemical pumps; sixth-generation ultra-low carbon stainless steel high-quality leak-free molten urea pumps; urea hydrolyzer feed pumps; high-temperature asphalt pumps; pitot tube pumps; rotary jet pumps; molten salt pumps; vertical sump pumps; magnetic drive pumps; high-temperature nitric acid magnetic drive pumps; magnetic drive pumps for conveying solid-containing media; industrial pumps; canned motor pumps; slurry pumps; titanium tetrachloride pumps; strong self-priming pumps; lined fluorine pumps; sandwich-lined fluorine pumps; leak-free pumps; alkali pumps; pumps; oil pumps; axial flow pumps; Ti alloy pumps; forced circulation pumps; specialized filter press pumps; long-shaft vertical sump pumps; CQC first-level energy efficiency chemical pumps; high-pressure descaling industrial pumps; and China chemical pumps. www.jslgpump.com Contact number: 13905263417 E-mail: jslgpump@gmail.com E-mail: jsareva@163.com