Do petrochemical companies use air compressors?
Technical description on the application of air compressors in petrochemical enterprises
Air compressors play an indispensable role in the petrochemical production system, and their application runs through many core aspects such as process control, equipment operation and maintenance, and safety assurance. After systematically sorting out industry technical specifications and practical cases, the application scenarios and technical points are now explained as follows:
1. Application of core processes
- Gas pressurization and delivery
- Hydrogen compression: In hydrocracking, residual oil hydrogenation and other units, air compressors provide supercharged power for the hydrogen circulation system to ensure that the reaction pressure is stable at 8 – 15 MPa
- Nitrogen supply: Continuous reforming, polypropylene and other units need to continuously supply 0.5 – 1.0MPa nitrogen. The air compressor is linked with the nitrogen production system to ensure the supply of protective gas.
- Ethylene transportation: In the cracked gas compression unit, the air compressor pressurizes ethylene gas to 3.5 – 4.0MPa, meeting the requirements for long-distance pipeline transportation
- instrument control system
- Pneumatic actuator: Provide 0.4 – 0.6MPa clean air source for regulating valves, shut-off valves, etc., ensuring control accuracy ≤ ± 1%
- Analytical instrument sampling: compressed air drives the online analytical instrument sampling system to ensure the normal operation of precision equipment such as chromatographs and mass spectrometers
- Back-blowing system: Provide pulse back-blowing source for dust filters and CEMS smoke monitoring systems to prevent clogging of measuring units
2. Equipment operation and maintenance support
- Purge and replace
- Pipeline purging: Before the new device is put into use, use 1.0-1.5MPa compressed air for blasting to remove welding residues and impurities
- Equipment replacement: During equipment maintenance, combustible gas is replaced with compressed air to ensure the safety of hot work
- Catalyst regeneration: In fluidized bed catalytic cracking units, compressed air is used for catalyst scorch regeneration, with a temperature control accuracy of ±10℃
- power drive system
- Fan drive: Provides pneumatic motor power for large blowers and induced draft fans, saving energy by 15-20% compared with motor drive
- Pump start and stop: In flammable and explosive areas, use pneumatic diaphragm pumps instead of electric pumps to improve the intrinsic safety level
- Tool power: Provide power source for air wrenches, polishers and other maintenance tools to reduce the risk of electric shock
3. Safety and environmental protection guarantees
- fire protection system
- Pneumatic fire cannon: In high-risk areas such as oil tank areas and loading and unloading platforms, compressed air-driven fire cannons achieve remote and precise fire extinguishing
- Foam generation: Linkage with the fire water pump to provide air source for the foam fire extinguishing system. The foam mixing ratio control accuracy is ±5%
- Emergency breathing: Equipped with positive pressure air breathing apparatus to provide safe breathing guarantee for more than 30 minutes for emergency personnel
- Environmental Protection treatment
- Waste gas incineration: In the RTO regenerative incinerator, compressed air combusts natural gas to ensure that VOCs removal efficiency is ≥99%
- Sewage treatment: Provide air source for air flotation devices and aeration tanks, and improve COD removal rate by 10-15%
- Dust control: In the process of pulverized coal preparation, catalyst loading and unloading, compressed air drives the bag-type dust collector, with an emission concentration of ≤10mg/m³
4. System configuration specifications
- Equipment selection requirements
- Explosion-proof level: In explosive dangerous areas, use ExdIIBT4Gb explosion-proof compressor
- Material requirements: The parts in contact with the medium are made of 316L stainless steel, and the corrosion resistance is improved by 3 times.
- Lubrication method: Oil-free compressors are equipped at key workstations to ensure that the oil content of the compressed air is ≤0.01mg/m³
- Pipe network design standards
- Pipeline grade: The process gas pipeline adopts Sch 40S stainless steel pipeline, with a design pressure of 1.6-4.0MPa
- Vibration reduction measures: The inlet and outlet of the compressor are equipped with metal hoses, and the vibration attenuation rate is ≥80%
- Drainage system: Automatic drainage valves are installed every 50 meters of pipes to prevent condensation from accumulating
5. Key points of operation and maintenance management
- daily monitoring
- Vibration testing: Carry out bearing vibration testing daily, with vibration speed ≤4.5mm/s (ISO 10816-1 standard)
- Temperature recording: Record the main engine temperature, oil temperature, and exhaust temperature every hour to establish a temperature curve
- Leakage inspection: Use a laser methane detector to conduct leakage detection in the pipe network every month, and the leakage rate should be <0.5%
- regular maintenance
- Lubricating system: Replace synthetic lubricating oil every 2000 hours, and test the oil viscosity change ≤10%
- Filtration system: Replace precision filters every 500 hours, and the filter core pressure difference is ≤0.2MPa
- Cooling system: Clean dust on cooler fins every quarter to ensure heat dissipation efficiency ≥95%
It is recommended that petrochemical companies establish a compressed air quality management system (CAQMS) and incorporate the gas supply system into the scope of process safety management. For new construction or renovation projects, HAZOP analysis should be carried out to optimize system configuration. During equipment overhaul, the compressor should be comprehensively inspected, including main machine flaw detection, performance testing, etc. Regularly carry out operator training, focusing on strengthening the operating procedures and emergency response capabilities of explosion-proof equipment to ensure the safe and stable operation of the device.