Nitrogen generator, nitrogen purification, PSA, membrane, air.
Nitrogen generator
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Nitrogen is required for various industrial processes. The Haber-Bosch process for the synthesis of ammonia and the production of calcium cyanamide are the most important examples. The use as a protective gas or inert gas and thus the prevention of oxidation is also a common application. This is used to prevent fire, explosion, corrosion or unstable chemical syntheses. Nitrogen can either be purchased directly in gas containers, temporarily stored in nitrogen tanks or generated by a gas generator. The nitrogen generator is a good alternative to replace liquid, compressed nitrogen bought in bottles. The self-sufficient on-site purification of air to nitrogen offers several advantages:
In contrast to air separation according to Linde, which cools and liquefies gases by means of expansion, two different systems are used in our systems. These generate gaseous nitrogen at lower cost. We differentiate between pressure swing generators (PSA) and membrane generators.
To separate oxygen and thereby purify nitrogen (N2) from the air, the so-called Pressure Swing Adsorption (PSA) is used. This is a physical process that takes advantage of the different adsorption properties of various gases at different pressures to separate them from each other. Depending on the implementation, it is also possible to separate other gases such as carbon dioxide. To separate oxygen and generate high-purity nitrogen, oxygen-affine materials such as carbon molecular sieves (CMS) are used. The process is based on the principle that oxygen and nitrogen molecules are adsorbed differently by the micropores of the molecular sieves due to their different diffusion rates. Oxygen molecules (O2) have a smaller diameter than nitrogen molecules (N2) and therefore diffuse more quickly into the micropores of the molecular sieve. Nitrogen molecules, on the other hand, diffuse more slowly and are thus less retained in the pores. This causes oxygen to accumulate in the molecular sieve, while nitrogen remains in the gas phase and can be extracted at the system’s outlet as high-purity nitrogen. The nitrogen production process can deliver nitrogen with a purity of up to 99.9995%. During the process, the gas flow is directed through two parallel adsorption towers. One of the towers adsorbs oxygen under pressure, while the other tower is regenerated under reduced pressure by releasing the adsorbed oxygen. This alternation of adsorption and regeneration is monitored by a fully automated control system that precisely manages the pressure swing and the sequence to ensure continuous nitrogen production. Depending on the regeneration pressure, a distinction is made between vacuum regeneration and normal pressure regeneration. Normal pressure regeneration is particularly advantageous as it allows the complete regeneration of the molecular sieves and supports the continuous production of high-purity nitrogen. The performance of the molecular sieves, measured by dynamic adsorption capacity and separation coefficient, is critical to the efficiency and quality of the nitrogen generator. Through programmable logic control (PLC), the system can precisely coordinate the process of pressure buildup and pressure reduction in the adsorption towers to achieve the required purity and amount of nitrogen.
Unlike pressure swing adsorption, a membrane generator uses polymer hollow fiber membranes to primarily remove oxygen from the gas flow.
The separation of nitrogen and oxygen takes place in the membrane separators. These always consist of a bundle of the above-mentioned hollow fibers and are gathered in a cylindrical shell.
Based on the selective pass through and therefore different strong interactions of the gases with the hollow fiber, these can be separated. Each gas has a characteristic penetration rate.
So there exists "fast" gas like oxygen and "slow" gas like nitrogen. By applying a pressure difference between the compressed inlet gas and
low pressures behind the membrane, dry compressed air is selectively transferred through the membrane wall. As nitrogen migrates along the inside of the fiber and thus can form a nitrogen-rich product stream,
oxygen emerges quickly from the fiber again and can therefore be vented at atmospheric pressure.
A nitrogen membrane generator is always made up of several hollow fiber bundles and offers a simple
solution for generating nitrogen gas.
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Our nitrogen generators are used in various industrial utilization. Depending on the area of application, we can adapt our generators individually to customer requirements.
➣ Automotive industry
In the automotive industry and for automotive suppliers, nitrogen is mainly required in form of inert gas for welding work. Here nitrogen is used as a so-called auxiliary substance.
➣ Lithium-ion battery industry
At the battery composition, the nitrogen requirement is comparatively low at around 150N m3/h. However, the purity requirements are over 99.9 %. At the production of the starting materials, the requirement is usually significantly higher. Our systems can also handle a particularly high purity of 99.9995%. Nitrogen is required for manufacturing lithium iron phosphate, ternary material systems, graphite anodes, carbon nanotubes or supercapacitors.
➣ Marine Industry
Large quantities of nitrogen are required for manufacturing ship parts for oil tankers or chemical tankers. Here purities between 95 and 99% are sufficient.
➣ Electronic industry
A high purity of over 99.99% is required in the production of electronic parts such as LEDs, diodes, capacitors, SMTs, electrical ceramics or the stacking of chips.
➣ Heat treatment
In the production of car parts, gears, tools, or fastening elements, in addition to pure nitrogen, gas mixtures with carbon monoxide (CO), carbon dioxide (CO2) or ammonia (NH3) are used. The gases are used as protective gas or inert gas for furnace applications. Here usually are high demands on the purity of the gases.
➣ Powder metallurgy
In powder metallurgy, gas mixtures with hydrogen and high purity are used to manufacture the various materials such as tungsten, magnesium, copper, iron or aluminum powder.
➣ Synthetic fibers
The manufacture of synthetic fibers requires high purities and large capacities of N2
➣ Cable industry
For the production of fire-resistant, aluminum-coated or copper-shielded cables, nitrogen gas with high purity is required
➣ Brazing industry
Pure nitrogen is used when brazing aluminum parts. Even the smallest impurities are a problem here. For this reason, our systems produce nitrogen with a purity of 99.9995%. Nitrogen is also required when brazing copper. Here mixtures of nitrogen and hydrogen are mostly used.
➣ Iron & steel industry
For steel and iron production, nitrogen or a nitrogen-hydrogen mixture of particularly high purity is used. These gases are required for manufacturing stainless steel, galvanized and cold-rolled sheet metal as well as silicon steel.
➣ Copper processing
The same requirements as to steel processing apply to the production of copper tubes, copper rods and copper strips. A backup system with liquid nitrogen is often required in both areas.
➣ Food
In food industry, nitrogen is used in the packaging, preservation and filling of beverages. Food also stays fresh longer. In this way, fruit, salad and vegetables can already be packed in the greenhouse, agricultural business or farm. Furthermore, the durability significantly longer when packing meat in the slaughterhouse and fish in the port under a protective gas atmosphere. Moderate purity of the gas is often sufficient here.
➣ Pharmaceutical industry
In the pharmaceutical industry, particularly high requirements apply to comply with legal standards. This is easily possible with our systems.
➣ Household Appliances Industry
For the production of devices such as air conditioning systems, refrigerators and air purifiers, nitrogen with various purities starting at 99% is used
➣ Oil & Gas Industry
In the oil and gas industry, many processing steps are only possible with nitrogen. These include processes that affect chlor-alkali compounds, coal, natural gas and other chemicals.
➣ Tungsten Molybdenum Industry
Both tungsten and molybdenum are characterized by a high density. To produce the powders made from this material, nitrogen with a purity of up to 99.999% is also required.
➣ Laser applications
A continuous supply of high-purity nitrogen is essential for laser cutting or other applications. Our generators can ensure a sufficiently high quality here.
Crystec will be pleased to engineer a cost effective system to satisfy your most demanding and exacting requirements.