When recovering boil-off gas (BOG), it is crucial to choose the right compressor, which depends on many factors such as the characteristics of BOG, the requirements of the recovery process, and the cost. Common types of compressors suitable for BOG recovery are reciprocating compressors, screw compressors, and centrifugal compressors, each of which has different characteristics and applicable scenarios.
1. Reciprocating compressor
Applicable scenarios: When the BOG recovery system requires a high compression ratio and compresses BOG to a very high pressure, a reciprocating compressor is a good choice. For example, in some small LNG filling stations or industrial production projects where a small amount of BOG is generated, these sites have high requirements for the final pressure of BOG and the processing volume is relatively small. Reciprocating compressors can meet these requirements well.
Advantages: Reciprocating compressors have a high compression ratio and can compress BOG gas to a very high pressure to meet the requirements of subsequent processing processes. It has strong adaptability to gas and can handle BOG gas of different compositions and properties. In addition, at a high compression ratio, the efficiency of reciprocating compressors is good.
2. Screw compressor
Applicable scenarios: Screw compressors are suitable for BOG recovery projects with large processing volumes and certain ranges of compression ratio requirements. For example, large LNG receiving stations or industrial production parks where a large amount of BOG is generated require compressors to operate stably at a large flow rate while meeting certain compression ratio requirements.
Advantages: The screw compressor has a simple and compact structure, small size, light weight, and small footprint, making it easy to install and arrange in places with limited space. It runs smoothly, has low vibration and low noise, which is conducive to improving the service life of the equipment, reducing the occurrence of equipment failures, and providing operators with a relatively quiet and comfortable working environment. In addition, the screw compressor has a high speed and can process a large amount of BOG gas in a short time, with a high gas flow rate and processing capacity.
3. Centrifugal compressor
Applicable scenarios: Centrifugal compressors are suitable for BOG recovery projects with large processing volumes, high requirements for equipment stability and working environment, not particularly high requirements for compression ratio, and relatively stable BOG gas flow. For example, large LNG receiving stations, petrochemical enterprises, etc. produce a large amount of BOG and have relatively low pressure requirements.
Advantages: The centrifugal compressor has a large gas flow rate and can process a large amount of BOG gas in a short time, which is particularly suitable for BOG recovery projects with large processing volumes. Its structure is relatively simple and the number of parts is small, which makes the equipment manufacturing, installation and maintenance relatively convenient and the cost is relatively low. At the same time, the centrifugal compressor runs smoothly, with low vibration and low noise, which not only helps to improve the service life and operating efficiency of the equipment, but also provides a relatively quiet and comfortable working environment for operators.
There is no type of compressor that is absolutely suitable for recovering evaporation gas. It is necessary to comprehensively evaluate and compare the advantages and disadvantages of different types of compressors according to specific project requirements, such as BOG flow, pressure requirements, gas composition and budget, so as to select the most suitable compressor to achieve efficient recovery of evaporation gas.
