Air compressor plays a vital role in the petrochemical industry, and its role runs through the whole production process. It is the core equipment to ensure process safety, improve product quality and achieve energy saving and consumption reduction. The following is a professional exposition from the four dimensions of process support, equipment assurance, safety and environmental protection, and energy efficiency optimization:
1. core process support
- catalytic cracking process
- the air compressor provides the fluidizing air required by the regenerator for the catalytic cracking unit to maintain the catalyst circulation. For example, in a catalytic cracking unit with an annual processing capacity of one million tons, a multi-stage centrifugal air compressor is required, and the exhaust pressure reaches 1.0-1.5MPa to ensure the catalyst activity.
- hydrocracking reaction
- hydrogen circulation power is provided for the hydrogenation reactor to ensure stable reaction pressure. For example, in the diesel hydrogenation unit, the air compressor needs to be linked with the circulating hydrogen compressor to control the pressure of the reaction system at 8-15MPa to ensure the hydrogenation depth.
- gas separation and purification
- in the air separation unit, the air compressor compresses the feed gas to 0.6-0.8MPa to provide power for the subsequent cryogenic separation. For example, a large petrochemical enterprise through the configuration of centrifugal air compressor, to achieve oxygen purity ≥ 99.6%, nitrogen purity ≥ 99.999%.
2. key equipment support
- pneumatic actuator drive
- provide power source for pneumatic valves and regulating valves of the whole plant to ensure rapid opening and closing of process pipelines. For example, in an emergency shutdown system (ESD), the air compressor must respond within 0.5 seconds to actuate the valve to close.
- Instrument control system air supply
- provide clean gas source for pressure transmitters, flow meters and other instruments to ensure measurement accuracy. For example, in a high-pressure polyethylene plant, the instrument air dew point needs to be ≤-40°C, and the oil content is ≤ 0.01 mg/m & sup3; to avoid pipeline blockage.
- Gas supply for special process equipment
- air supply for pneumatic pumps, pneumatic stirrers and other equipment to achieve safe operation without sparks. For example, in flammable and explosive solvent recovery units, the air compressor needs to meet Ex dIIBT4 explosion-proof rating.
3. safety and environmental protection requirements
- specification for explosion-proof design
- the motor shall be of increased safety type or positive pressure ventilation type with protection grade ≥ IP55. For example, in refinery atmospheric and vacuum distillation units, air compressors need to pass ATEX explosion-proof certification to ensure safe operation in explosive gas environments.
- Leakage Control Standard
- double ferrule or welding seal shall be used at the pipe connection, and the leakage rate shall be ≤ 1 × 10 and Pa · m & sup3;/s. For example, at a liquefied natural gas (LNG) terminal, the air compressor system needs to pass a helium leak test to ensure that there are no minor leaks.
- Exhaust gas treatment system
- configure a catalytic oxidation unit to reduce the concentration of volatile organic compounds (VOCs) to 120 mg/m & sup3; below. For example, a petrochemical enterprise through the installation of RTO (regenerative oxidation furnace), so that the air compressor exhaust gas treatment efficiency of 98%.
4. energy efficiency optimization technology
- variable Frequency Drive Application
- automatically adjust the speed according to the gas load, the power saving rate can reach 30%-40%. For example, in an ethylene plant, by configuring an inverter air compressor, the annual power saving exceeds 2 million kWh.
- waste heat recovery system
- the hot water of 65-80 ℃ is prepared by using compression heat to meet the needs of process preheating. For example, a refinery reduces steam consumption by 30000 tons per year through heat recovery technology.
- intelligent control system
- integrated pressure sensor, flow meter and PLC controller to achieve:
- gas consumption real-time monitoring
- air compressor group joint control (automatic start and stop according to load)
- leak alarm and location
5. typical application scenarios
| Scene | key parameter requirements | technical Solutions |
|---|
| catalytic cracking unit | pressure 1.0-1.5MPa, flow rate 500-2000m & sup3;/min | multi-stage centrifugal air compressor with anti-surge control system |
| polypropylene Production | pressure 0.7MPa, dew point -40 ℃, oil content ≤ 0.01 mg/m & sup3; | oil-free screw air compressor + three-stage filtration system |
| flare gas recovery | pressure 0.3MPa, flow fluctuation range 30%-120 | variable frequency drive screw air compressor + air storage tank buffer system |
| hydrogen pressurized conveying | pressure 15MPa, continuous operation ≥ 8000 hours | diaphragm air compressor with on-line condition monitoring system |
air compressors have become an indispensable core equipment in the petrochemical industry by providing stable air sources, driving key equipment, ensuring process safety and achieving energy efficiency optimization. With the improvement of the industry's requirements for energy saving and consumption reduction, the proportion of applications of high-efficiency models such as permanent magnet frequency conversion, water lubrication and oil-free is increasing year by year, promoting the transformation of the petrochemical industry to a green and low-carbon direction.
