plants offer a compact, reliable and cost effective alternative to
vaporized liquid for some nitrogen users, in particular, those that have
relatively steady demand rates between about 15,000 SCFH to 40,000 SCFH.
LIN-assist plants use a simplified cryogenic separation cycle that eliminates mechanical refrigeration equipment and replaces it with injection of a small amount of liquid nitrogen. The vaporizing liquid provides the refrigeration required for air separation and nitrogen purification. Typically, more than 95% of the plant product is freshly-produced gaseous nitrogen, with the remainder vaporized liquid.
|LIN-assist plants can produce gaseous nitrogen
for less than half the cost of liquid nitrogen (LIN) when demand is
relatively steady. The actual
savings, versus 100% LIN vaporization, will depend upon the match between
plant capacity and peak user demand (similar flow rates are best), user
demand pattern (24/7 at steady rates is
best), local power cost, and length of supply contract
(shorter contracts require higher annual capital cost amortization).
If user demand is relatively low, and variable, either a traditional liquid supply may be more appropriate, or, if nitrogen purity is not a critical parameter, a non-cryogenic system might be the most economical supply source. See the graphic on this page.
The LIN-assist nitrogen production process is similar to that used in conventional cryogenic nitrogen plants. The only significant difference is that LIN import and vaporization is used to provide the refrigeration necessary to cryogenically separate air by low temperature distillation and purify the product instead of a mechanical refrigeration cycle. Typically, when producing at a relatively constant rate near its rated capacity, 20 to 30 units of gaseous nitrogen can be produced by the plant for every unit of LIN consumed.
LIN-assist plants are inherently reliable, as they have less mechanical equipment than a conventional cryogenic plant and most components run at continuous steady-state conditions. LIN storage and vaporization is an inherent part of the system. Vaporized LIN is automatically provided to meet short-term demand peaks and back up the air separation process. LIN-assist plants are compact units requiring very little area to install.
GAN Production (Nm3/hr) Minimum
Pressure Bar (g)
|ULAP 750||500||800||< 10 ppm O2||7|
|ULAP 1000||700||1,050||< 10 ppm O2||7|
GAN Production (SCFH) Minimum
|ULAP 750||19,000||30,500||< 10 ppm O2||100|
|ULAP 1000||26,500||40,000||< 10 ppm O2||100|
Plants based on LIN-assist technology offer savings compared to using 100% vaporized LIN. They are one of several potential supply options, especially in the lower production rate end of the application range.
Non-cryogenic processes are most attractive when nitrogen purity may be lower than "LIN purity" (e.g. 98 to 99.5% is sufficiently pure).
At the higher end of the range, LIN-assist competes against convention cryogenic separation processes.
|Many factors enter into
selection of the best technology choice in the capacity range where
LIN-assist plants are a possible technology choice. UIG will
examine your situation, including your current requirements and your
expectations regarding future changes.
When choosing a system that is expected to be your nitrogen source for many years, the selection process must not only reflect current costs for power and liquid nitrogen, and current usage rates and patterns, but future expectations regarding how these important variables may change. In most cases, more than one technology could be a reasonable choice.
UIG wants to help you select and install the best choice for your particular situation.
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.