The types of gases involved in natural gas recovery are indeed quite diverse. In addition to helium, light hydrocarbons, hydrogen sulfide, carbon dioxide, and nitrogen mentioned earlier, there are also some other gases and products worth paying attention to. The following is a more detailed analysis of the gases and products involved in the natural gas recovery process:
1. Mainly recover gases and products
Helium gas:
Helium is a rare gas with low content in natural gas, but it has unique physical and chemical properties such as extremely low boiling point, high thermal conductivity, and chemical inertness.
The methods for extracting helium from natural gas mainly include low-temperature separation, membrane separation, and adsorption separation. Among them, low-temperature separation method is the most commonly used method, which separates helium gas from other gases by lowering the temperature.
After further purification and upgrading, the extracted helium gas can achieve high purity and is widely used in scientific research, medical, aerospace, electronics and other fields.
Light hydrocarbons:
Light hydrocarbons refer to the heavier hydrocarbon components in natural gas, such as ethane, propane, butane, etc. The content of these hydrocarbon components in natural gas varies depending on the gas field.
Light hydrocarbon recovery usually adopts technologies such as low-temperature separation or absorption separation. The low-temperature separation method separates light hydrocarbons from other gases by lowering the temperature, while the absorption separation method utilizes the adsorption effect of absorbents on light hydrocarbons for separation.
The recovered light hydrocarbons can be used as fuel or chemical raw materials, such as for the production of chemicals such as ethylene and propylene.
Hydrogen sulfide (H ₂ S):
Hydrogen sulfide is a toxic gas that can pose a threat to the environment and human health when present in high concentrations in natural gas.
In the process of natural gas processing, the removal of hydrogen sulfide is usually achieved through chemical absorption or physical absorption methods. The chemical absorption method uses alcohol amine or alkaline salt solutions to absorb hydrogen sulfide, while the physical absorption method uses organic solvents to separate the solubility of hydrogen sulfide.
The removed hydrogen sulfide can be sent to the sulfur recovery unit for recycling and conversion into sulfur, an important chemical raw material.
Carbon dioxide (CO ₂):
Carbon dioxide is one of the common impurities in natural gas, and its content and composition vary depending on the source of natural gas.
In natural gas processing, the removal of carbon dioxide is usually achieved through absorption, membrane separation, or adsorption separation methods. These methods can effectively separate carbon dioxide from natural gas.
The removed carbon dioxide can be captured and stored to reduce greenhouse gas emissions. In addition, carbon dioxide can also be used to produce carbonated beverages, dry ice, and other products.
Nitrogen (N ₂):
Nitrogen usually exists in a free state in natural gas, and its content is relatively low.
During natural gas liquefaction or helium recovery, nitrogen may be removed as impurities. However, in some cases, nitrogen can also be recovered and utilized.
The recycled nitrogen can be used for the production of nitrogen fertilizers, refrigerants, and other products, or as an inert gas in fields such as chemical engineering and electronics.
2. Other products during natural gas processing
Liquefied Natural Gas (LNG):
Natural gas can be compressed, cooled, and liquefied to obtain liquefied natural gas. Liquefied natural gas has advantages such as high calorific value, easy storage and transportation.
Liquefied natural gas is widely used in the field of energy supply, such as as as urban gas, ship fuel, and automotive fuel.
Sulfur:
The hydrogen sulfide removed from natural gas can be converted into sulfur through a sulfur recovery unit. Sulfur is an important chemical raw material widely used in the manufacture of products such as sulfuric acid and fertilizers.
Other by-products:
During natural gas processing, other by-products such as ammonia and water may also be produced. These by-products can be further processed and utilized based on their properties and applications.
In summary, the natural gas recovery process involves a wide variety of gas types and products. By reasonable recycling and utilization, not only can the efficiency of natural gas utilization be improved, but environmental pollution and resource waste can also be reduced. Therefore, in the process of natural gas recovery, attention should be paid to the comprehensive treatment and utilization of various gases and products.
In the process of natural gas recovery, in addition to the main recovered gases such as liquefied natural gas (LNG), sulfur, helium, light hydrocarbons, hydrogen sulfide, carbon dioxide, and nitrogen mentioned earlier, various other products can also be produced. Here are further supplements to these products:
1. Chemical processing products
Synthetic ammonia:
Natural gas is the best raw material for producing nitrogen fertilizers (synthetic ammonia), with the characteristics of low investment, low cost, and low pollution. Natural gas can be steam converted or partially oxidized to produce synthesis gas, which can then be used to synthesize ammonia.
Methanol:
Methanol is one of the world's major organic chemical products, a key product in carbon chemistry, an important chemical raw material, and also one of the future clean energy sources. After steam conversion, natural gas can be used to produce methanol, which is widely used in the production of plastics, synthetic fibers, synthetic rubber, dyes, coatings, spices, feed, pharmaceuticals, and more.
Ethylene, propylene and other olefins:
Light hydrocarbons such as ethane and propane in wet natural gas can be steam cracked or thermally cracked to produce olefins such as ethylene and propylene. These olefins are important raw materials for the chemical industry and can be used to produce various products such as plastics, rubber, synthetic fibers, etc.
2. Other energy and chemical products
Natural gas to synthetic oil (GTL):
With the breakthrough of natural gas synthetic oil technology and related technologies, natural gas to synthetic oil has become competitive. The synthetic oil produced from natural gas does not contain environmental pollutants such as aromatic hydrocarbons, heavy metals, sulfur, etc. It is an environmentally friendly and high-quality fuel with a vast consumer market.
Liquefied Petroleum Gas (LPG):
Liquefied petroleum gas is a type of petroleum exhaust gas left over from the process of refining gasoline, kerosene, diesel, heavy oil, and other oil products. It can also be obtained by pressurizing, cooling, and liquefying natural gas (including associated gas from oil fields). LPG is a colorless, volatile gas that exists in a liquid state inside a gas cylinder. Once it flows out, it vaporizes into a combustible gas that is approximately 250 times its original volume and is highly prone to diffusion. It can ignite or explode when exposed to an open flame. LPG is mainly used as fuel and also as a chemical raw material.
Hydrogen gas:
Natural gas can be used to produce hydrogen gas through methods such as steam reforming or partial oxidation. Hydrogen is a clean energy carrier and can also be used for various reactions in chemical production.
Reuse of carbon dioxide:
In the process of natural gas recovery, the removed carbon dioxide can not only reduce greenhouse gas emissions through capture and storage, but also be used in other industrial processes such as urea production and carbonate synthesis.
3. Environmental protection and by-products
Wastewater treatment:
The wastewater generated during the natural gas treatment process needs to be treated before it can be discharged. During the wastewater treatment process, valuable substances can be recovered while reducing environmental pollution.
Waste gas utilization:
In some natural gas recovery processes, the waste gases generated (such as nitrogen, methane, etc.) can be recovered and utilized. For example, nitrogen can be used to produce nitrogen fertilizers or other chemical products, while methane can be used as fuel.
In summary, there are various types of products in the process of natural gas recovery, covering multiple fields such as energy, chemical industry, and environmental protection. The rational utilization of these products can not only improve the efficiency of natural gas utilization, but also promote the development of related industries and environmental protection.
