In the production operations of the salt chemical industry, process media generally contain high-concentration salts such as sodium chloride and magnesium chloride, featuring strong corrosiveness, easy crystallization and scaling, and frequent salting-out blockages. Under such harsh and complex working conditions for a long time, chemical pumps are prone to various faults including flow passage scaling, component corrosion and wear, mechanical seal leakage, abnormal bearing vibration and cavitation damage.
The traditional extensive operation and maintenance mode lacks unified standards, with perfunctory inspections, random lubrication management and no definite basis for wearing part replacement. It not only greatly shortens the service life of equipment, but also causes frequent production line shutdowns, raises costs for equipment maintenance and spare parts replacement, and restricts the efficient and continuous production of enterprises.
To effectively solve the operational pain points of chemical pumps under high-salt working conditions and standardize the whole-process maintenance work, Zoomlian Pump Industry, a professional chemical pump manufacturer, shares a systematic maintenance plan to slow down the aging of chemical pump components in this paper. This plan can effectively improve the operational stability and service life of chemical pumps, and help salt chemical enterprises realize equipment cost reduction, stable production and efficient operation.
Establish a three-level inspection system. Operators conduct visual checks on bearing temperature and seal leakage every day; detect impeller radial runout and evaluate alignment deviation with vibration analyzers every week; inspect internal corrosion and scaling thickness of flow passages via endoscopes monthly, and compile Chemical Pump Condition Inspection Reports. Issue early warnings for components with wear degree exceeding the threshold (e.g. seal ring clearance over 0.3mm).
Match special lubricating grease for different chemical pump models in accordance with ISO12928 standards (lithium complex grease is preferred in salt fog environments). Adopt progressive distributors to ensure accurate oil injection volume of 0.5ml each time into bearing chambers. Test oil contamination degree every 500 operating hours (NAS1638 grade ≤ Grade 8), and purify unqualified oil with vacuum oil filters of 10μm filtration precision.
For media containing sodium chloride and magnesium chloride, adopt a two-stage filtration system (80-mesh pre-filter screen and 5μm precision post-filter element). Install on-line pH meters at pump inlets to monitor salting-out critical points and start backwashing procedures when pH value exceeds 6.5. Dismantle impellers for ultrasonic cleaning (40kHz frequency, cleaning solution temperature 60℃±5℃) every 800 operating hours to remove salt scale crystal layers.
Build a classified spare parts warehouse. Adopt SKF6310/C3 P6 precision bearings and fluororubber U-shaped seals (applicable temperature: 20℃~200℃). Adjust replacement cycles dynamically based on MTBF values, and extend the service life of mechanical seals to 1200 hours in salt fog environments. Keep original wear morphology analysis reports for all replaced parts.
Realize load adaptive control via SCADA system. Automatically adjust the frequency of variable-frequency motors when pump outlet pressure fluctuates beyond ±0.05MPa, keeping flow rate within ±2% of the rated value. Calculate net positive suction head (NPSH) monthly, and activate anti-cavitation protection procedures when the actual value is 0.3m lower than the designed value.
Apply a three-layer anti-corrosion protection system on pump casings: zinc-rich epoxy primer, glass flake intermediate coat and PTFE top coat, with total dry film thickness no less than 120μm. Carry out surfacing welding with Hastelloy C276 on impeller flow surfaces (hardness ≥45HRC), and adopt TC4 titanium alloy for shaft sleeves. Establish anti-corrosion coating inspection ledgers to record coating adhesion (no less than Grade 5B by cross-cut test).
Compile Operation and Maintenance Manual for Chemical Pumps in Salt Chemical Industry covering key operating requirements specified in API610 11th Edition. Hold fault simulation drills quarterly to assess practical skills including vibration spectrum analysis and seal ring clearance measurement, ensuring a 100% certified staff rate.
Set up electronic files for each chemical pump to record factory parameters, maintenance records, spare part models and cumulative operating hours. Generate predictive maintenance reports through big data analysis, and push spare parts replacement early warnings 72 hours in advance.
Verified by numerous salt chemical enterprises, the above measures can extend the average mean time between failures (MTBF) of chemical pump sets by 40% and cut spare parts replacement costs by 35%, greatly improving production continuity.