Pressure Swing Adsorption
Universal Industrial Gases specializes in cryogenic plants, but some
nitrogen users have relatively low levels of demand and do not require
high purity nitrogen and/ or need the nitrogen to support cyclic demand
profiles. When this is the case, UIG may advise users to explore other
types of production technology offered by companies specializing in
non-cryogenic production units. One type of non-cryogenic production unit
is a nitrogen PSA. They can be highly efficient and reliable,
and are small in size and operate automatically.
Savings of 40% or more compared to cylinder gas or bulk liquid delivery prices are common.
Nitrogen PSA generation units are readily available to meet the needs of users with demand up to approximately 40,000 SCFH.
A typical system will consist of a UIG nitrogen PSA skid sized to meet their base load demand, coupled with a buffer tank to match relatively constant production rates with varying demand rates. Depending upon severity of flow variations and the criticality of maintaining availability of product at all time, a small liquid nitrogen storage and vaporization system may be used to back up the PSA and meet significant short-term peaks. .
Most nitrogen users users do not require very high purity nitrogen, However they get it automatically when they buy liquid nitrogen. Lower purity gas is less expensive to make and there is no need to double or triple the energy usage to make liquid for the sole purpose of transport to the user site. Maximum savings versus vaporizing trucked-in liquid nitrogen are obtained when the units produce 95 to 99.5% oxygen-free product. If higher purity is required, systems can be added to the core unit to produce product with purity very close to that of vaporized liquid nitrogen (up to 99.000%).
|Typical Low Production Rate Nitrogen PSA||
Typical Higher Capacity Nitrogen PSA System
Compressor, Drier, Adsorbers, Gas Storage
Deoxo Units purify
to 99.999% Purity
UIG offers an onsite gas supply option for larger volume users:
For users with usage rates and demand profiles best suited to a PSA
supply, but who wish to avoid the immediate capital cost of installation,
and ongoing operations support, UIG offers nitrogen PSA-based onsite gas supply systems to customers requiring more
about 10,000 SCFH or more of product
(about 7 million SCF/mo, 260 Nm3/h, or 190,000 Nm3/mo).
UIG will install the plant at the customer's site and provide operations support and periodic maintenance services. Where necessary, UIG can include liquid nitrogen storage and vaporization systems to handle short-duration demand peaks and/ or irregular usage patterns and provide backup nitrogen vaporization capacity to ensure continuous product availability.
Onsite nitrogen supply agreements typically include an initial supply period of seven to ten years. These arrangements minimize customer investment and customer involvement in nitrogen generator operations and maintenance. They give the customer the same kind of utility-like supply that is associated with all liquid nitrogen supplies - but at lower cost.
Nitrogen users which normally consume less than 10,000 SCFH will normally maximize their cost savings by purchasing a nitrogen PSA generator. In these cases, UIG can provide assistance with installation, as well as monitoring and maintenance services, if desired.
A range of models and options provide low first cost and low operating cost:
Nitrogen PSA models are available to meet a wide range of production rates and product purities. Units can be provided to produce nitrogen at any purity from 95% to >99.5%; as set by user needs. By operating the nitrogen generator to produce the required purity required for the application, but not over-purifying, savings will be maximized.
99.5% purity product, if needed, can be produced at rates as low as 200 SCFH (5 Nm3/h) or as high as 1000 Nm3/hr (38,000 SCFH).
Typical delivery pressures are in the range of 6 to7 Bar(g) (87 to 102 psig). Higher pressures are available with the aid of a booster compressor. Units are designed for outdoor or indoor installation. Specific features to accommodate extreme weather conditions, hazardous environments, cylinder filling and other situations are available.
Nitrogen can be produced at very high purity (e.g. 99.999%) by adsorption or, often more cost-effectively, by a two-step process that couples a 99.5% purity PSA with a "de-oxo" unit to reduce residual oxygen to the required level.
Nitrogen PSA System Features:
Universal Industrial Gases, Inc.
Universal Cryo Gas, LLC
3001 Emrick Blvd., Suite 320
Bethlehem, Pennsylvania 18020 USA
Phone (610) 559-7967 Fax (610) 515-0945
All material contained herein Copyright 2003 / 2015 UIG.