The nitrogen making machine refers to a equipment that uses air as raw material and uses physical methods to separate oxygen and nitrogen in it to obtain nitrogen. The nitrogen machine used in industry can be divided into three types according to the different classification methods, namely, the cryogenic air separation method, the molecular sieve air separation method (PSA) and the membrane air separation method.
Nitrogen Generation System
Nitrogen making machine is a nitrogen making equipment designed and manufactured according to pressure swing adsorption technology. The nitrogen making machine uses high quality imported carbon molecular sieve (CMS) as adsorbent and adopts pressure swing adsorption principle (PSA) at normal temperature to separate air and produce high purity nitrogen. Two adsorption towers are usually used in parallel, and the imported pneumatic valve is controlled by an imported PLC to operate automatically, alternately perform pressure adsorption and decompression regeneration, complete the separation of nitrogen and oxygen, and obtain the required high purity nitrogen.
The operating principles of three types of nitrogen generators
Principle of PSA pressure swing adsorption nitrogen production
Carbon molecular sieves can simultaneously adsorb oxygen and nitrogen from the air, and their adsorption capacity increases with increasing pressure. Moreover, there is no significant difference in the equilibrium adsorption capacity of oxygen and nitrogen at the same pressure. Therefore, it is difficult to achieve effective separation of oxygen and nitrogen solely based on changes in pressure. If we further consider the adsorption rate, we can effectively distinguish the adsorption characteristics of oxygen and nitrogen. The diameter of oxygen molecules is smaller than that of nitrogen molecules, so the diffusion rate is hundreds of times faster than that of nitrogen. Therefore, the adsorption rate of oxygen on carbon molecular sieves is also very fast, reaching over 90% in about 1 minute; At this time, the adsorption capacity of nitrogen is only about 5%, so the adsorbed oxygen is mostly oxygen, while the rest is mostly nitrogen. In this way, if the adsorption time is controlled within 1 minute, oxygen and nitrogen can be initially separated. That is to say, adsorption and desorption are achieved by pressure difference, with adsorption occurring when the pressure increases and desorption occurring when the pressure decreases. The distinction between oxygen and nitrogen is based on the difference in their adsorption rates, which is achieved by controlling the adsorption time. If the time is controlled to be very short, oxygen will be fully adsorbed while nitrogen will stop before it can be adsorbed.
Principle of cryogenic air separation for nitrogen production
Cryogenic nitrogen production can not only produce nitrogen but also liquid nitrogen, meeting the process requirements for liquid nitrogen, and can be stored in liquid nitrogen storage tanks. When there is a nitrogen interruption load or minor maintenance of the air separation equipment, the liquid nitrogen in the storage tank enters the vaporizer and is heated before being sent into the product nitrogen pipeline to meet the nitrogen demand of the process equipment. The operating cycle of cryogenic nitrogen production (referring to the interval between two large heating cycles) is generally more than 1 year, therefore, cryogenic nitrogen production generally does not consider backup. However, pressure swing adsorption nitrogen production can only produce nitrogen gas without backup means, and a single set of equipment cannot guarantee continuous long-term operation.
Principle of membrane air separation for nitrogen production
After being compressed and filtered by the compressor, the air enters the polymer membrane filter. Due to the different solubility and diffusion coefficients of various gases in the membrane, the relative permeation rates of different gases in the membrane are different. According to this characteristic, various gases can be divided into “fast gas” and “slow gas”.
When the mixed gas is subjected to the pressure difference on both sides of the membrane, gases with relatively fast permeation rates, such as water, hydrogen, helium, hydrogen sulfide, carbon dioxide, etc., pass through the membrane and are enriched on the permeate side of the membrane, while gases with relatively slow permeation rates, such as methane, nitrogen, carbon monoxide, and argon, are retained on the permeate side of the membrane and enriched, thus achieving the goal of mixed gas separation.
Equipment features of nitrogen generator machine
Convenient and fast
Advanced technology and unique airflow distributor make the airflow distribution more uniform and efficiently utilize carbon molecular sieves, providing qualified nitrogen gas in about 20 minutes.
Easy to use
The equipment has a compact structure, is assembled as a whole, occupies a small area, does not require infrastructure investment, and has low investment. Nitrogen can be produced on site by simply connecting the power supply.
Economics
The PSA process is a simple nitrogen production method that uses air as raw material and consumes only the electrical energy consumed by the air compressor. It has the advantages of low operating costs, low energy consumption, and high efficiency.
Automated operation
Imported PLC controls fully automatic operation, with adjustable nitrogen flow rate, pressure and purity, and continuous display, enabling unmanned operation.
Widely applicable
Protective gases for metal heat treatment processes, production gases in the chemical industry and nitrogen purification of various storage tanks and pipelines, production gases for rubber and plastic products, oxygen removal and preservation packaging in the food industry, purification and covering gases in the beverage industry, nitrogen filling and oxygen removal of packaging and containers in the pharmaceutical industry, and protective gases for electronic components and semiconductor production processes in the electronics industry. Purity, flow rate, and pressure are stable and adjustable to meet the needs of different customers.
Main classification of nitrogen generators
Cryogenic air separation for nitrogen production
Cryogenic air separation for nitrogen production is a traditional nitrogen production method with a history of nearly several decades. It uses air as raw material, undergoes compression and purification, and then uses heat exchange to liquefy the air into liquid air. Liquid air is mainly a mixture of liquid oxygen and liquid nitrogen. By utilizing the different boiling points of liquid oxygen and liquid nitrogen (at 1 atmosphere, the former has a boiling point of -183 ℃, while the latter has a boiling point of -196 ℃), they are separated through liquid air distillation to obtain nitrogen gas. The cryogenic air separation nitrogen production equipment is complex, occupies a large area, has high infrastructure costs, requires a large one-time investment in equipment, has high operating costs, produces gas slowly: 12-24h, has high installation requirements, and has a long cycle. Taking into account factors such as comprehensive equipment, installation, and infrastructure, the investment scale of PSA units with the same specifications for equipment below 3500Nm3/h is 20% to 50% lower than that of cryogenic air separation units. The cryogenic air separation nitrogen production unit is suitable for large-scale industrial nitrogen production, while medium and small-scale nitrogen production appears uneconomical.
Molecular sieve air separation for nitrogen production
The method of using air as raw material, carbon molecular sieve as adsorbent, and pressure swing adsorption principle to selectively adsorb oxygen and nitrogen by carbon molecular sieve to separate nitrogen and oxygen is commonly known as PSA nitrogen production. This method is a new nitrogen production technology that rapidly developed in the 1970s. Compared with traditional nitrogen production methods, it has the advantages of simple process flow, high degree of automation, fast gas production (15-30 minutes), low energy consumption, adjustable product purity within a large range according to user needs, convenient operation and maintenance, low operating costs, and strong device adaptability. Therefore, it is highly competitive in nitrogen production equipment below 1000Nm3/h and is increasingly popular among small and medium-sized nitrogen users. PSA nitrogen production has become the preferred method for small and medium-sized nitrogen users
Membrane air separation for nitrogen production
Using air as raw material, under certain pressure conditions, different gases with different properties such as oxygen and nitrogen are used to separate oxygen and nitrogen in the membrane with different permeation rates. Compared with other nitrogen production equipment, it has the advantages of simpler structure, smaller volume, no switching valves, less maintenance, faster gas production (≤ 3 minutes), and convenient capacity expansion. It is particularly suitable for small and medium-sized nitrogen users with nitrogen purity ≤ 98%, and has the best functional price ratio. When the purity of nitrogen is above 98%, its price is more than 15% higher compared to PSA nitrogen generators of the same specifications.
Application industries of nitrogen production systems
The specialized nitrogen generator for the oil and gas industry is suitable for nitrogen protection, transportation, coverage, replacement, emergency rescue, maintenance, nitrogen injection and oil recovery in mainland oil and gas extraction, coastal and deep-sea oil and gas extraction. It has the characteristics of high safety, strong adaptability, and continuous production.
The specialized nitrogen generator for the chemical industry is suitable for the processing of petrochemical, coal chemical, salt chemical, natural gas chemical, fine chemical, new materials and their derivative chemical products. Nitrogen is mainly used for covering, blowing, replacing, cleaning, pressure conveying, chemical reaction agitation, chemical fiber production protection, nitrogen filling protection and other fields.
The specialized nitrogen generator for the metallurgical industry is suitable for fields such as heat treatment, bright annealing, protective heating, powder metallurgy, copper and aluminum processing, magnetic material sintering, precious metal processing, and bearing production. It has the characteristics of high purity, continuous production, and some processes require nitrogen to contain a certain amount of hydrogen to increase brightness.
The specialized nitrogen generator for the coal mining industry is suitable for fire prevention and extinguishing, gas and gas dilution, and other fields in coal mining. It has three specifications: ground fixed, ground mobile, and underground mobile, fully meeting the nitrogen demand under different working conditions.
The specialized nitrogen generator for the rubber tire industry is suitable for nitrogen protection and molding during the vulcanization process of rubber and tire production. Especially in the production of all steel radial tires, the new process of nitrogen vulcanization has gradually replaced the steam vulcanization process. It has the characteristics of high nitrogen purity, continuous production, and high nitrogen pressure.
The specialized nitrogen generator for the food industry is suitable for green storage of grain, nitrogen filling packaging of food, preservation of vegetables, sealing (canning) and storage of alcoholic beverages, etc.
Explosion proof nitrogen generators are suitable for places with explosion-proof requirements such as chemical, petroleum and natural gas industries.
The specialized nitrogen generator for the pharmaceutical industry is mainly used in fields such as drug production, storage, packaging, and packaging.
The electronic industry specific nitrogen generator is suitable for semiconductor production packaging, electronic component production, LED, LCD liquid crystal display, lithium battery production and other fields. The nitrogen generator has the characteristics of high purity, small size, low noise, and low energy consumption.
Container type nitrogen generators are suitable for petroleum, natural gas, chemical, and other related fields, and have the characteristics of strong adaptability and mobile operation.
Vehicle mounted mobile nitrogen generation vehicles are suitable for fields such as oil and gas extraction, pipeline blowing, replacement, emergency rescue, dilution of flammable gases and liquids in the oil and gas industry. They are divided into low-pressure, medium pressure, and high-pressure series, and have the characteristics of strong mobility and mobile operation.
Automobile tire nitrogen filling machine, mainly used for nitrogen filling of automobile tires in 4S stores and repair shops, can extend the service life of tires, reduce noise and fuel consumption.