There are various methods for natural gas recovery, mainly including the following:
1、 Gas compression method
Gas compression method refers to the pressurization of natural gas to reduce its volume, thereby reducing space consumption during storage and transportation. For example, compressed natural gas (CNG) that has been properly processed can be used as a vehicle fuel, thereby reducing the use of fossil fuels. CNG has advantages such as environmental protection, safety, and economy, and is a very practical method for natural gas recovery.
2、 Gas liquefaction method
Gas liquefaction refers to the physical conversion of natural gas into a liquid state to reduce its volume and increase its energy density. Liquid natural gas (LNG) is a natural gas recovery product obtained during the reprocessing of natural gas, which can be used in fields such as fuel, power generation, and shipping. In the future development of energy, liquefied natural gas will inevitably become an important component.
3、 Fuel cell method
A fuel cell is a device that converts chemical energy into electrical energy. It reacts natural gas (or other fuel gases) with oxygen to produce electricity and water, while also producing small amounts of carbon dioxide and other exhaust gases. Due to the relatively small amount of exhaust gas generated by the reaction and the relatively high electricity output, fuel cells are one of the most environmentally friendly and practical natural gas recovery methods.
4、 Adsorption method
Adsorption method is a method of using adsorbents to adsorb and separate natural gas. According to the different adsorbents, they can be divided into two types: physical adsorption and chemical adsorption. Physical adsorption is the use of the physical properties of adsorbent surfaces to adsorb natural gas, while chemical adsorption is the use of chemical reactions between adsorbents and natural gas for adsorption. The adsorption method has the advantages of easy operation, low investment, and small footprint, but the regeneration and replacement costs of the adsorbent are relatively high.
5、 Membrane separation method
Membrane separation is a method of separating natural gas using polymer membranes. According to the different membrane materials, they can be divided into two types: organic membranes and inorganic membranes. Organic membranes are commonly used for the recovery of low-pressure natural gas, while inorganic membranes are suitable for the recovery of high-pressure natural gas. The membrane separation method has the advantages of simple equipment, convenient operation, and low energy consumption, but the lifespan and stability of the membrane need to be further improved.
6、 Natural gas injection technology
Natural gas injection technology is based on the principles of fluid mechanics, using high-pressure natural gas to inject low-pressure natural gas, thereby achieving the recovery and utilization of natural gas. This technology mainly includes high-pressure gas inlet, low-pressure gas inlet, nozzle, mixing chamber, and expansion section. In the utilization of natural gas injection technology, natural gas passes through the nozzle position, and low pressure appears in the mixing chamber. The low pressure natural gas is sucked in and mixed to form a high-speed mixed airflow, which is pressurized in the expansion section and then transmitted.
7、 Other methods
In addition to the common natural gas recovery methods mentioned above, there are also other methods such as low-temperature separation, 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 natural gas recovery, each with its unique advantages and scope of application. In practical applications, it is necessary to choose appropriate methods for recycling and utilization based on specific circumstances to improve the efficiency and economic benefits of natural gas utilization.
When evaluating which natural gas recovery method is best, multiple factors need to be considered, including the composition of natural gas, pressure, temperature, recovery efficiency, cost, environmental impact, and usage. The following is a comprehensive evaluation of several major natural gas recovery methods:
Gas compression method:
Advantages: By compressing a small volume of natural gas, it is easy to store and transport, especially when used as a vehicle fuel, it has advantages such as environmental protection, safety, and economy.
Disadvantages: It requires a certain amount of energy to pressurize, and the recovery efficiency of high-pressure natural gas may be limited.
Gas liquefaction method:
Advantages: Converting natural gas into liquid form can greatly reduce volume, increase energy density, and is suitable for long-distance transportation and large-scale storage.
Disadvantages: The liquefaction process requires a large amount of energy consumption, and the construction and maintenance costs of liquefaction equipment are relatively high.
Fuel cell method:
Advantages: It directly converts natural gas into electricity and water, which is environmentally friendly and efficient, and produces less waste gas.
Disadvantages: The manufacturing cost of fuel cells is relatively high, and at the current level of technology, their energy conversion efficiency still needs to be improved.
Adsorption method:
Advantages: Easy to operate, low investment, small footprint, suitable for the recovery of low-pressure natural gas.
Disadvantages: The regeneration and replacement costs of adsorbents are relatively high, and the recovery efficiency for high concentration natural gas may not be high.
Membrane separation method:
Advantages: Simple equipment, easy operation, low energy consumption, suitable for natural gas recovery at specific pressures and temperatures.
Disadvantages: The lifespan and stability of the membrane need to be further improved, and the separation effect for complex natural gas compositions may be poor.
Natural gas injection technology:
Advantages: Utilizing high-pressure natural gas to inject low-pressure natural gas without the need for additional power sources, suitable for the recovery and utilization of low-pressure natural gas.
Disadvantages: The recovery efficiency of high-pressure natural gas is limited, and specific equipment design and installation conditions are required.
Taking into account the above factors, there is no method that can be considered the absolute best natural gas recovery method. In practical applications, comprehensive consideration and selection should be made based on various factors such as the specific situation of natural gas, the purpose of recovery, and economic and environmental benefits. For example, for natural gas that requires long-distance transportation or large-scale storage, gas liquefaction may be more suitable; For scenarios that require direct conversion into electrical energy, the fuel cell law has more advantages.
Therefore, when choosing a natural gas recovery method, it is recommended to conduct a detailed technical and economic assessment and environmental impact analysis to ensure the selection of the most suitable method for the current situation. Meanwhile, with the continuous advancement of technology and the reduction of costs, there may be more efficient and environmentally friendly natural gas recovery methods emerging in the future.
