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China Carbon Molecular Sieve
has been at the leading edge of Carbon Molecular Sieve
Frontier in China since its establishment and CMS products
have been exported to a number of countries and regions in
Asia, America and Europe. The techniques for production of
high quality CMS developed in our company have been awarded
a number of prizes for contributions in science and
technology by the National and the Provincial as well as the
Molecular Sieve Co, Ltd. will provide you and the new
as well as old clients in nitrogen-making with our
first-class brand and service.
The carbon molecular sieve (CMS)is a kind of?
nonpolarity? sorbent. It has the performance to absorb
oxygen in the air under changing pressure of normal
temperature and acquire rich nitrogen gas through Pressure
Swing Adsorption (PSA) process.
A. The Major Models of CMS
CMS-180 CMS-190 CMS-200 CMS-210 CMS-220
B. The Principle of producing nitrogen
A carbon molecular sieve belongs to the kind of carbon
sorbent and it is the carbon skeletal flamework, which is a
disordered accumulation of carbon. The capability of air
separating is based on its skeletal framework. In dynamics,
CMS has different adsorptive rate for oxygen and nitrogen.
Under balanced condition , the adsorption by CMS towards O2
and N2 is very close, however, the speed O2 molecule passing
through the framework is faster than N2 molecule, this
principle is the bases of CMS N2 generation. Before the
adsorption, oxygen and other impurities are adsorbed by the
CMS, allowing unabsorbed nitrogen to pass through the bed.
C. Nitrogen generator by CMS
This apparatus is often called Air Separation Nitrogen
Plants. The process uses the principle of Pressure Swing
Adsorption(PSA).Pressure-swing adsorption nitrogen-making is
realized through the features that CMS has, of selective
adsorption and the difference adsorption capacity under
different pressure. Oxygen molecular are withheld by carbon
molecular sieve because its spreading speed is much quicker
than nitrogen molecular in the carbon molecular sieve'
minute hole structure when the pressure is raising, while
the adsorption to nitrogen molecular are relieved by the
oxygen gas. It makes carbon molecular sieve regenerate,
forms circulatory operation, and realizes nitrogen-making
The PSA process includes; Pressure adding,
Nitrogen producing, Pressure balancing; Pressure reducing,
Nitrogen releasing; then repeat these procedures
again,...and the circulation process was formed by these
procedures .According to the style of regeneration, the
process can be concluded into regelaeration in vacuum
process (VPSA)and regeneration in normal pressure process.
According to the demands of clients, the
nitrogen generation plant based on the PSA-process can
consist into; the air pressing and purifying system,
pressure swing and adsorption system, programmable valve
controller system(the VPSA process even in need of the
vacuum pump),and Nitrogen supply system.
D. The principle in controlling
nitrogen generation by CMS
1.Air compressing and purifying process.
It is very necessary to let purified air into
the adsorption tower, because if mote and organic gas
entered the adsorptiorn tower, they will jam the skeletal
framework, later it will lower the effects of generating.
The means to purify air; a. To keep the inlet
of air compressing machine far away from dust, oil frog as
well as organic gas; b. The raw material air, which pumped
into the CMS adsorption tower, should first get through
filter and cooler, also the purifying system filled with
sorbent, later it will undergo a further transaction.
2.The N2 purity and production capacity.
When generation nitrogen by CMS, the N2
concentration and production capacity can be adjusted
according to the needs of users. In a certain time and under
a certain pressure, when reducing the production, the purity
would rise; Otherwise, it would fall. User can adjust
according to their practical needs.
3.The time period for pressure balancing.
In the process of generation, when one tower
ends its adsorption, the compressed air can be immitted both
from top and bottom into the other adsorption towers which
had been regenerated, and then the two towers reach the same
pressure, this process is called the pressure balancing
between the two adsorption towers. If choosing a proper time
for pressure balancing, it cannot only reclaim the energy,
but also reducing the impingement CMS received, as a result,
the purpose of prolonging the longevity of CMS is reached.
With the reference to the speed of valve switching, the time
for pressure balancing should be 1 to 3s.
4.N2 producing time period.
According to the fact that CMS have different
rate in adsorption of N2 and O2.as it can saturate in a
short time when adsorbing O2,while at the same time the
amount of N2 adsorbed is small. The relatively short time
period of nitrogen generation can also adds the frequency of
valve switching, SO the performance of the valve is also
very important. The normal time period of adsorption is 30
to 120s.Small-sized high purity N2 generator is recommended
to have short period of generation time, while large-sized
low purity generation long.
CMS has both the effect of dynamics and the
effects of adsorption by depressurization. The capacity of
adsorption raises when the pressure put on to the CMS is
high, so adsorption by adding pressure is favorable, but the
pressure adding demands higher model of air compressor.
Concerning adsorption pressure, the
requirements in the process of normal pressure regeneration
and vacuum generation is different. After considering an
these conditions, the adsorption pressure under normal
pressure is suggested to choose 5 to 8kg/cm2, vacuum 3 to
As a sorbent, the relatively lower tempemture
is good for the exertion of CMS. If possible, it is
favorable for the nitrogen generator to lower the
temperature of adsorption.
E. The package and usage of the
1.The products undergo strict check and
measure in line with the standards of our company, so as to
insure the quality of the product.
2.The products are airproofed in plastic
barrels; the performance of hermetic package is reliable,
open when padding into the generation towers, proof from
3.The padding should be tight, please make
them tight and firm with proper method, don't pug it with a