How Industrial Gas Generators Work
Industrial nitrogen and oxygen generators can produce nitrogen or oxygen on demand for a fraction of the cost of conventional nitrogen and oxygen sources such as cylinders, dewars or bulk liquid supply.
Nitrogen and oxygen can be generated from atmospheric air. The air we breathe is composed of 78% nitrogen and 21% oxygen. The remaining 1% is trace gases. Nitrogen molecules are much larger than oxygen molecules and we use the size difference between these two molecules to physically separate atmospheric air.
There are two primary types of technology available for generating nitrogen on site, PSA type nitrogen generators and membrane type nitrogen generators.
PSA type generators have pressure vessels that are filled with a material called carbon molecular sieve or CMS. CMS is a porous material with the ability to adsorb under pressure right down to the molecular level. To produce nitrogen, a compressed air stream is passed through a pressure vessel filled with CMS. The porosity structure of CMS allows the material to capture and adsorb the smaller oxygen molecules as the compressed air flows through. This leaves a stream of larger nitrogen molecules to flow out the opposite end of the pressure vessel for process use.
Membrane type generators are used to produce nitrogen only and can be cost effective if nitrogen purities of 98% or less are required for an application. With these types of generators, a compressed air stream is introduced into the membranes. The membranes are semi-permeable and under pressure, the smaller oxygen molecules are filtered out leaving a stream of nitrogen flowing out the opposite end of the membrane. Membrane type generators are generally considered to be ultra-reliable because there are typically few parts that can fail.
Oxygen generators also use PSA technology to produce oxygen but a different type of sieve material called zeolite is used. Once again, a compressed air stream is passed through a pressure vessel filled with zeolite. The porosity structure of Zeolite allows the material to capture and absorb the larger nitrogen molecules as the compressed air flows through, leaving a stream of oxygen to flow out the opposite end of the pressure vessel.
Advanced Gas Technologies Inc. will sell nitrogen or oxygen generating systems outright or install systems on long-term gas supply contracts. Customers who decide to purchase systems outright can typically expect a pay back on their capital expenditure within six months to two years, depending on the individual application. Systems installed on gas supply contracts can typically cut ongoing nitrogen or oxygen costs between 40 – 75% with no capital outlay from a prospective client.