Implementation strategy for stable protection measures of all carbon steel slag

All carbon steel slag oil pumps are widely used in heavy oil transportation areas due to their cost advantages. However, carbon steel is prone to wear, corrosion, and thermal deformation under high temperature, high viscosity, and corrosive media conditions, which affects equipment stability. To ensure the long-term operation of the slag oil pump, a systematic protection system needs to be constructed from dimensions such as material, structural optimization, operation management, and maintenance upgrades.

1、 Material and Process Protection

1. Surface hardening treatment

The inner surface of the carbon steel pump body in contact with the medium needs to be inspected. Hard alloy welding process can be used to form a hard layer in key parts such as impellers and volutes, which can resist the erosion and wear of solid particles in residual oil. A certain refining enterprise has significantly improved the service life of the pump inlet section by welding tungsten carbide coating on it. For high-temperature working conditions, cobalt based alloy welding materials can be used, which have better resistance to heat and thermal fatigue.

2. Coating application

A protective coating should be applied to the surface of carbon steel to address the corrosive components such as sulfides contained in residual oil. The chemical stability and adhesion of epoxy resin coatings can form a dense isolation layer; Ceramic coatings possess both non corrosive properties and are suitable for high-temperature media environments. After spraying ceramic coating inside the pump body of a certain chemical plant, the corrosion rate significantly decreased and the maintenance cycle of the coating was extended.

3. Improvement of heat treatment process

Optimize the heat treatment parameters of carbon steel forgings, remove tissue stress, and improve material toughness. The use of quenching and tempering process can achieve a uniform tempered martensite structure on the pump shaft, enhancing its fatigue resistance; For thick walled components such as pump bodies, it is necessary to control the quenching cooling rate to prevent cracking. A certain pump factory has significantly improved the fracture toughness of key components of the slag oil pump by improving the heat treatment process.

2、 Structural adaptability optimization

1. Anti erosion structure

Optimize the geometric parameters of the impeller to reduce the impact force of the medium on the blades. The use of rear curved blades can reduce fluid detachment and energy loss; Setting strips at the edge of the blade inlet can disperse the impact energy of solid particles. After the renovation of a heating enterprise, the wear rate of the impeller significantly decreased and the maintenance cycle was extended.

2. Thermal expansion compensation mechanism

To address the issue of thermal deformation under high temperature conditions, a correct expansion compensation structure is required. Elastic connection is adopted at the connection between the pump body and the bearing seat, allowing for slight axial displacement; Install expansion joints to absorb thermal stress in the pipeline and prevent deformation of the pump body under stress. After adding expansion joints to a petrochemical plant, the problem of pump body seal leakage has been solved.

3. Sealing system upgrade

Choose a sealing form that can withstand high temperatures and prevent wear. Mechanical seals should adopt a balanced structure to reduce the end face pressure ratio; The auxiliary sealing ring is made of fluororubber or perfluoroether material to maintain elasticity at high temperatures. For media containing solid particles, a combination of hard to hard sealing surfaces can be used to enhance performance. After the renovation of a certain refinery, the sealing life has been significantly improved and the leakage rate has been greatly reduced.

3、 Accurate control of the operation process

1. Medium temperature management

Strictly control the inlet temperature of residual oil to avoid local overheating and material performance degradation. Maintain medium temperature uniformity and reduce thermal stress concentration through a thermal oil circulation system; Set temperature measurement points on the pump body to monitor temperature distribution in real-time. A certain enterprise has optimized the heating process to reduce the temperature fluctuation range of the pump body and decrease the amount of thermal deformation.

2. Flow pressure regulation

Avoid running the pump at deviations from operating conditions to prevent cavitation or vibration. By using frequency conversion speed regulation technology to achieve continuous flow control, the pump can operate in a good speed range; Install pressure buffering devices in the inlet and outlet pipelines to control pressure pulsation. After the renovation of a certain chemical plant, the operational stability of the pump was significantly improved and the noise was reduced.

3. Start stop program specifications

The established start stop operation procedures reduce the impact of thermal shock. Adequate preheating is required before starting to ensure a uniform increase in the temperature of the pump body; When stopping the machine, the inlet and outlet valves should be closed first, and then the motor should be stopped to prevent the medium from flowing back and causing water hammer effect. After strict implementation of preheating procedures in a certain thermal power plant, the incidence of pump body cracks significantly decreased.

4、 Upgrade and implement maintenance strategy

1. Application of state monitoring technology

Establish an online monitoring system based on vibration and temperature to assess the real-time health status of equipment. Identify fault characteristics such as bearing wear and rotor imbalance through spectrum analysis; Infrared temperature measurement can locate localized overheating areas. A certain enterprise detected bearing faults in advance through a monitoring system and completed replacement before the faults expanded, avoiding unplanned shutdowns.

2. Preventive maintenance system

Develop a graded maintenance plan and determine the maintenance cycle based on the importance of the equipment. Key components undergo state maintenance, while auxiliary components are replaced regularly; Establish maintenance files to record the content of each maintenance and information on replacement parts. A certain pump factory has significantly improved the average time between failures of slag oil pumps by implementing preventive maintenance.

3. Optimization of spare parts management

Reserve key vulnerable parts and ensure quick recovery of production in case of sudden failures. Implement quality traceability management for consumables such as coatings and seals, and select verified suppliers; Regularly inventory and promptly eliminate aging spare parts. A certain refining enterprise has significantly reduced the repair time for faults by optimizing spare parts management.

The stable operation of the all carbon steel slag oil pump requires a full lifecycle of installation and operation. Through the coordinated implementation of material, structural optimization, operation control, and maintenance upgrades, the equipment's risk resistance ability can be significantly improved, creating sustained economic benefits and stable value for the enterprise.