The methods of natural gas compression mainly include the following:
1、 Mechanical compression
Mechanical compression is currently one of the most widely used natural gas compression methods. It uses a compressor to compress gas to a certain pressure. The commonly used mechanical compression methods include centrifugal, axial, and screw compression.
Centrifugal compressor: uses a rotating impeller to do work on gas, allowing the gas to gain energy and thus increase its pressure. Centrifugal compressors have the advantages of high flow rate, high efficiency, and smooth operation, and are suitable for large-scale and continuous natural gas compression.
Axial flow compressor: compresses gas through axial flow blades and has the characteristics of simple structure, small volume, and light weight. Axial compressors are suitable for small and medium-sized natural gas compression.
Screw compressor: compresses gas through two interlocking screws, which has the advantages of high efficiency, stable operation, and low noise. Screw compressors can be used in natural gas compression equipment of various scales.
2、 Liquid cascade compression
Liquid cascade compression is a method of compressing liquefied natural gas (LNG), commonly used in liquefied gas containers. The principle is to utilize the heat absorption and release characteristics of gas to transfer cooling liquid into the interior of LNG containers, and then compress and recover it. Although the cost of liquid cascade compression is high, it has the characteristics of high compression ratio and high energy efficiency.
3、 Membrane separation compression
Membrane separation compression is an efficient natural gas compression method that uses specially designed membranes to separate and compress gases. Membrane separation compression is commonly used in high-pressure natural gas compression, including traditional membrane separation and twisted flow (TD) membrane separation. This method has the advantages of simplicity, energy conservation, and pollution-free, especially suitable for small-scale natural gas compression equipment.
4、 Other methods
In addition to the three main natural gas compression methods mentioned above, there are also other methods such as adsorption, chemical absorption, physical absorption, etc. The selection of these methods depends on factors such as the composition, pressure, temperature, and purpose of recovery of natural gas.
In summary, there are various methods for compressing natural gas, each with its unique advantages and applicable scope. In practical applications, it is necessary to choose appropriate methods for compression and recycling according to specific situations. Meanwhile, with the continuous advancement of technology and the reduction of costs, there may be more efficient and environmentally friendly natural gas compression methods emerging in the future.
The mechanical compression, liquid cascade compression, and membrane separation compression methods in natural gas compression have significant differences in multiple aspects. The following is a detailed comparison of these three methods:
Mechanical compression:
This method compresses natural gas to the required pressure through a compressor. Mechanical compression has the characteristics of easy operation and wide applicability, and can handle natural gas compression needs of various scales and types. Its compression ratio is relatively large, usually up to 20 times or more, suitable for multiple fields such as refrigeration, gas pressurization, and gas transportation. However, the energy consumption of mechanical compression is relatively high, and the maintenance cost of the equipment may also increase due to long-term operation and wear.
Liquid cascade compression:
Liquid cascade compression mainly utilizes the heat absorption and release characteristics of gases to compress natural gas by cooling the liquid. This method can achieve a large compression ratio and has high energy efficiency. However, the cost of liquid cascade compression is relatively high as it requires complex cooling systems and equipment to support its operation. In addition, this method may also be more complex in terms of maintenance, requiring regular checks and maintenance of the cooling system to ensure its proper functioning.
Membrane separation compression:
Membrane separation compression uses specially designed membranes to separate and compress gases. This method has the advantages of simple operation, energy saving, and pollution-free, especially suitable for high-pressure natural gas compression and situations that require high-efficiency, pollution-free compression. However, the cost and technical difficulty of membrane separation compression are relatively high. The strength of the membrane is limited, the service life may be short, and it is easy to be contaminated, which affects the separation efficiency. Therefore, when choosing this method, it is necessary to comprehensively consider cost-effectiveness, technical feasibility, and maintenance requirements.
In summary, each natural gas compression method has its unique advantages and limitations. In practical applications, it is necessary to choose the appropriate compression method based on specific application scenarios, cost budgets, efficiency requirements, and maintenance needs. For example, in situations where a large amount of natural gas needs to be processed and there are certain cost requirements, mechanical compression may be a more suitable choice; In situations where high efficiency and pollution-free compression are required, membrane separation compression may have more advantages; For specific application scenarios such as liquefied gas containers and compression of liquefied natural gas (LNG), liquid cascade compression may be more suitable.
It is not easy to determine which method has the lowest cost in natural gas compression, as it depends on various factors including equipment purchase cost, operating cost, maintenance cost, and energy efficiency. However, in general, mechanical compression (especially centrifugal or axial compressors) may have a relative advantage in terms of cost.
Cost advantages of mechanical compression:
Equipment purchase cost: Mechanical compressors, especially centrifugal and axial compressors, have mature technology and wide applications in the market, so their equipment purchase cost may be relatively low. In addition, these devices usually have high reliability and durability, and can operate stably for a long time, thereby reducing the frequency of equipment replacement and maintenance.
Operating costs: Although mechanical compressors require a certain amount of energy during operation, their energy efficiency may be higher compared to other methods such as liquid cascade compression and membrane separation compression. This means that under the same compression amount, mechanical compressors may consume less energy, thereby reducing operating costs.
Maintenance cost: The maintenance of mechanical compressors is relatively simple, usually only requiring regular inspections and replacement of worn parts. Compared to other methods, its maintenance cost may be lower as it does not require complex cooling systems or regular replacement of membrane materials.
Cost considerations for other methods:
Liquid cascade compression: Although this method can achieve high compression ratios and energy efficiency, its cost is usually high. This is mainly due to the need for complex cooling systems and equipment to support its operation, as well as regular maintenance costs.
Membrane separation compression: Membrane separation compression may be costly due to the relatively high cost and technical difficulty of membrane materials. In addition, the strength of the membrane is limited, the service life may be short, and it is easy to be contaminated, which affects the separation efficiency and further increases maintenance costs.
Conclusion:
From a cost perspective, mechanical compression (especially centrifugal or axial compressors) may have relative advantages in natural gas compression methods. However, it should be noted that cost is not the only factor to consider. When choosing a natural gas compression method, it is also necessary to comprehensively consider multiple aspects such as equipment reliability, durability, energy efficiency, and maintenance requirements. Therefore, in practical applications, comprehensive consideration and selection should be made based on specific circumstances.
