U.S. patent application number 14/551065 was filed with the patent office on 2016-05-26 for absorption cooling air compressor system.
The applicant listed for this patent is Mingsheng Liu. Invention is credited to Mingsheng Liu.
Application Number | 20160146516 14/551065 |
Document ID | / |
Family ID | 56009854 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160146516 |
Kind Code |
A1 |
Liu; Mingsheng |
May 26, 2016 |
Absorption Cooling Air Compressor System
Abstract
An integrated absorption refrigeration and air compressor system
comprising an air compressor system for compressing air and an
absorption system for cooling air. The air compressor system
comprises at least one air filter for cleaning entering air, a
shut-off valve and plurality of bypass valves for blocking air from
entering the absorption system, a compressor for increasing the
pressure of the air, an after-cooler for cooling the air, a
receiver for storing the air, and a pressure regulation valve for
delivering the compressed air to end users. The integrated system
also comprises an absorption system for cooling air. The absorption
system comprises an evaporator for vaporizing air, an absorber for
creating a strong absorbent solution, a pump for pumping the
solution through the system, an economizer for heating the
solution, a generator for creating steam and weakening the
solution, a condenser for condensing the steam into a liquid.
Inventors: |
Liu; Mingsheng; (Omaha,
NE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Liu; Mingsheng |
Omaha |
NE |
US |
|
|
Family ID: |
56009854 |
Appl. No.: |
14/551065 |
Filed: |
November 23, 2014 |
Current U.S.
Class: |
62/483 |
Current CPC
Class: |
Y02B 30/62 20130101;
F25B 15/02 20130101; Y02A 30/277 20180101; Y02A 30/27 20180101 |
International
Class: |
F25B 25/02 20060101
F25B025/02 |
Claims
1. An integrated absorption refrigeration and air compressor system
for compressing and cooling air, said system comprising: an air
compressor system, said air compressor system comprising: at least
one air filter for filtering said air; at least one valve
downstream of said air filter for keeping said air within said air
compressor system; a compressor downstream of said plurality of
valves for compressing said air; an after-cooler downstream of said
compressor for cooling said air; a receiver downstream of said
after-cooler for storing said air; a pressure regulator valve
downstream of said after-cooler for regulating the amount of said
air that exits said system; an absorption system, said absorption
system of the type configured to operate on a continuous absorption
cycle using an absorbant, said absorption system comprising: an
evaporator for converting said air to a vapor; an absorber for
creating a strong solution from said vapor and said absorbant; at
least one pump for pumping said solution through said absorption
system; an economizer for recovering heat from said strong
solution; a generator for generating steam and a weak absorbant
solution from said strong solution; a condenser for condensing said
weak vapor absorbant from said generator into a liquid for
recycling through said absorption cycle.
2. The integrated absorption refrigeration and air compressor
system of claim 1, wherein said at least one air filter further
comprises an H-per filter.
3. The integrated absorption refrigeration and air compressor
system of claim 1, wherein said at least one air filter further
comprises an inlet air filter.
4. The integrated absorption refrigeration and air compressor
system of claim 1, further comprising a supply fan downstream of
said evaporator and configured to pull said air through said at
least one filter and evaporator
5. The integrated absorption refrigeration and air compressor
system of claim 4, further comprising at least one VFD in
connection with and configured to control the speed of said supply
fan and compressor.
6. The integrated absorption refrigeration and air compressor
system of claim 1, wherein said compressor is lubricant
injected.
7. The integrated absorption refrigeration and air compressor
system of claim 6, further comprising an oil cycle system in
communication with said lubricant injected compressing comprising
an oil cooler configured to cool said lubricant, and an oil
separator configured to separate said lubricant from said air.
8. The integrated absorption refrigeration and air compressor
system of claim 6, further comprising a coalescing filter
downstream of said compressor and configured to remove lubricant
from said stream of air.
9. The integrated absorption refrigeration and air compressor
system of claim 1, further comprising a deep dryer downstream of
said after-cooler and configured to lower the temperature and
reduce the moisture of said air.
10. The integrated absorption refrigeration and air compressor
system of claim 1, wherein said compressor is a multiple piston
compressor.
11. The integrated absorption refrigeration and air compressor
system of claim 1, wherein said compressor is a constant speed
compressor configured to turn on and off based on the pressure set
point.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM
LISTING COMPACT DISC APPENDIX
[0003] Not Applicable
TECHNICAL FIELD
[0004] The disclosed embodiments generally relate to air compressor
systems and, more particularly, to air compressor systems used in
industrial manufacturing plants, instruments, and other
applications.
DESCRIPTION OF THE RELATED ART
[0005] An air compressor system decreases the volume and increases
the pressure of a quantity of air by mechanical means. Compressed
air has a lot of potential energy because air expands rapidly upon
the removal of external pressure. The force of compressed air can
be used to power tools and devices that use air.
[0006] FIG. 2 is an illustration of the components of a
conventional air compressor system in the prior art. Typical prior
art air compressor system 200 is shown in FIG. 2 of the drawings.
Air filter 202 is typically located at the entrance of prior art
air compressor system 200. Air filter 202 is located upstream of
compressor 204 and filters out particles in the air to protect the
compressor from physical damage. Compressors use volumetric or
centrifugal compression to increase the air pressure so that it
reaches the required level needed. The compressor may be lubricant
free or lubricant injected. In the Figure, air separator 208 is
located downstream of air compressor 204 and functions to separate
the air and the lubricant. An air separator is not a necessary
component in lubricant free compressors. Lubricant cooler 206 cools
lubricants to a lower temperature range (typically in the range of
between 30.degree. C. to 50.degree. C.) to ensure the safe and
efficient operation of the compressor. If a lubricant injected
compressor is used, coalescing separator 210 is included to
separate the lubricant from the air and thus prevent it from being
trapped in after-cooler 212. Compressed air is cooled by after
cooler 212 to a lower temperature range (typically within the range
of 30.degree. C. to 50.degree. C.) in order to minimize the
capacity of the dryer and associated operating costs. After passing
through the after-cooler, the air becomes saturated. Cooling is
typically accomplished using air or water cooled heat exchangers.
Moisture separator 214 removes condensed liquid from the air
stream. Dryer 216 removes excess moisture in the system to satisfy
the process moisture requirement. Particulate air filter 218 is
generally installed downstream of dryer 216 to prevent adsorbed
matter from entering the distribution system. Since air is often
saturated after passing through air filter 218, any temperature
drop along the pipe has the potential to cause condensation (and
thus create issues during industry processes). Air receiver 220
stores enough air to minimize pressure fluctuations if the load
changes, and heater 222 is equipped to heat the air and prevent
condensation in the duct. Air pressure regulation valve 224
regulates the air pressure at a level required for the operation of
the process equipment.
[0007] The previously described compressor system is typical of air
compressor systems in the prior art. Such systems have drawbacks. A
major issue of prior art air compressor systems like the one
described is that high temperatures are needed and the amount of
moisture present is excessive. The compressor consumes more power
and does not operate very efficiently under these conditions. In
fact, when employed in summer weather conditions, it must be sized
up to 10% higher to meet the required capacity. In addition, the
filter, dryers, and separators of prior art compressor systems are
also affected by excessive pressure losses. These pressure losses
can equal up to 30% of the compressor head and consume up to 30% of
the total compressor power. The dryer and after cooler also consume
an excessive amount of energy in prior art systems (or as much as
15% of the total compressor power). The inefficiency of the
compressor is related to the low compressed air temperature. In
order to remove moisture, the compressed air temperature is often
cooled as low as 21.degree. C., thus reducing the air volume by as
much as 10%. Thus, in prior art systems, up to 10% of the
compressed air is wasted. Prior art compressed air systems
(excluding the distribution system) thus often use 20% to 45% more
power than is actually necessary.
[0008] Ideally, a system would be devised that can resolve the
system drawbacks in the prior art. However, at the current time
there is no known method or system which accomplishes this
objective.
SUMMARY OF THE INVENTION
[0009] The following summary of the invention is provided to
facilitate an understanding of some of the innovative features
unique to an embodiment of the present invention and is not
intended to be a full description. A full appreciation of the
various aspects of the invention can be gained by taking the entire
specification, claims, drawings, and abstract as a whole.
[0010] In one embodiment, an absorption cooling air compressor
system is proposed. The proposed system is comprised of an
integrated absorption and air compressor system. The integrated
system comprises an air compressor system for compressing air and
an absorption system for cooling air. The air compressor system
comprises, in series, at least one air filter for cleaning air
entering the system. A plurality of valves are located downstream
of the at least one air filter to keep air from entering the
absorption system. One of the plurality of valves, a shut-off
valve, allows air that is at a temperature above freezing to enter
the absorption system. The shut-off valve ensures that freezing air
is not cycled through the absorption system. The air compressor
system further comprises an air compressor located downstream of
the at least one air filter and configured to compress air that
enters it. An after-cooler is located downstream of the compressor
for cooling the air, a receiver downstream of the after-cooler for
storing the air, and a pressure regulation valve located downstream
of the receiver for delivering the compressed air at the desired
pressure to end users. In some embodiments, variable frequency
drives are connected to the fan and compressor and are configured
to modulate their speeds. In other embodiments, the system
comprises only one VFD connected to either the fan or
compressor.
[0011] The integrated absorption and air compressor system also
comprises an absorption system for cooling air. The absorption
system is cyclical in function and comprises an evaporator located
on the airflow line downstream of the at least one air filter and
shut-off valve and configured to vaporize water and entering air,
an absorber in communication with said evaporator and configured to
mix the vaporized water with an absorbent material to form a strong
absorbent solution, a pump in communication with the absorber for
pumping the solution through the system, an economizer in
communication with said pump and absorber and configured to heat
the solution, and a generator in communication with said economizer
and configured to create steam and weaken the solution. The
weakened solution then cycles back through the economizer and the
absorber, while the steam is cycled through a condenser. The
condenser is configured in communication with the generator and
condenses the steam into a liquid that is then cycled through at
least one expansion valve and back through the absorption system.
In some embodiments, the liquid is also cycled through a deep dryer
located on the airflow line of the absorption system downstream of
the after cooler.
[0012] In embodiments in which the compressor is lubricant
injected, the integrated air compressor and absorption system
comprises an oil cycle system. In such embodiments, an oil
separator and coalescing filter are configured in-line downstream
of the compressor for the purpose of separating the compressor oil
from the air and to filter the air, respectively. Embodiments that
include an oil cycle system also include an oil cooler configured
in connection with the compressor, generator, and oil separator
that cools the oil.
ADVANTAGES
[0013] Accordingly, it is one aspect of an embodiment to reduce the
moisture content in the air stream and inlet temperature. As a
result, annual energy consumption is reduced by 5% to 10%.
[0014] It is another aspect of an embodiment to eliminate the need
for an after cooler, moisture separator, and heaters.
[0015] It is a further aspect of an embodiment to install an H-per
filter upstream of the compressor to reduce both the equipment
costs and the required compressor head. This has the potential to
reduce energy consumed by the compressor by 10 to 20% and by up to
40% in applications that require very dry air.
[0016] It is yet a further aspect of an embodiment to reduce the
system pressure by installing an evaporator and fan upstream of the
compressor. When dry air is needed, the embodiments of the system
can save compressor energy by up to 40%. When it is implemented in
large compressed air plants, the proposed embodiment effectively
cools buildings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] It will be appreciated that for simplicity and clarity of
illustration, elements illustrated in the following figures have
not necessarily been drawn to scale. For example, the dimensions of
some of the elements are exaggerated relative to other elements for
clarity. Advantages, features, and characteristics of the present
disclosure, as well as methods and functions of related elements of
structure, and the combination of parts and economies of
manufacture, will become apparent upon consideration of the
following description and claims with reference to the accompanying
drawings, all of which form a part of the specification, wherein
like reference numerals designate corresponding parts in the
various figures, and wherein:
[0018] FIG. 1 is a schematic diagram of the system embodying the
principles of the absorption cooling air compressor system used for
compressing air.
[0019] FIG. 2 is a schematic diagram of an air compressor system in
the prior art.
FIG. 1 DRAWINGS REFERENCE NUMERALS
[0020] 100 Absorption Cooling Air Compressor System [0021] 102 Air
Inlet Filter [0022] 104 H-per Filter [0023] 106 Shut-off Valve
[0024] 108 Evaporator [0025] 110 Bypass Valve I [0026] 112
Expansion Valve I [0027] 114 Fan [0028] 116 Compressor [0029] 118
VFD I [0030] 120 VFD II [0031] 122 Oil Separator [0032] 124
Coalescing Filter [0033] 126 Generator [0034] 128 Bypass Valve 2
[0035] 130 Economizer [0036] 132 Absorber [0037] 134 Pump [0038]
136 Oil Cooler [0039] 138 Condenser [0040] 140 After Cooler [0041]
142 Deep Dryer [0042] 144 Receiver [0043] 146 Pressure Regulation
Valve [0044] 148 Expansion Valve II [0045] 150 Pressure Sensor I
[0046] 152 Temperature Sensor I [0047] 154 Temperature Sensor II
[0048] 156 Liquid Level Sensor I [0049] 158 Liquid Level Sensor II
[0050] 160 Temperature Sensor III [0051] 162 Pressure Sensor II
[0052] 164 Temperature Sensor IV
FIG. 2 PRIOR ART DRAWINGS REFERENCE NUMERALS
[0052] [0053] 200 Prior Art Air Compressor System [0054] 202 Air
Filter [0055] 204 Air Compressor [0056] 206 Air Separator [0057]
208 Lubricant Cooler [0058] 210 Coalescing Separator [0059] 212
After Cooler [0060] 214 Moisture Separator [0061] 216 Dryer [0062]
218 Air Filter [0063] 220 Air Receiver [0064] 222 Heater [0065] 224
Air Pressure Regulator
DETAILED DESCRIPTION
[0066] Before any embodiments of the invention are explained in
detail, it is to be understood that the disclosure is not limited
in its application to the details of construction and the
arrangement of components set forth in the following description or
illustrated in the following drawings. The disclosed is capable of
other embodiments and of being practiced or of being carried out in
various ways. Also, it is to be understood that the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limiting. The use of "including,"
"comprising," and variations thereof herein is meant to encompass
the items listed thereafter and equivalents thereof as well as
additional items. Unless specified or limited otherwise, the terms
"attached," "connected," "supported," and variations thereof herein
is meant to encompass the items listed thereafter and equivalents
thereof as well as additional items. Unless specified or limited
otherwise, the terms "attached,", "connected", "supported",
"communicated" and variations thereof are used broadly and
encompass both direct and indirect mountings, connections, and
supports. Further, "connected" and "communicated" is not restricted
to physical or mechanical connections.
[0067] FIG. 1 shown below illustrates an embodiment of the
disclosed absorption cooling air compressor system. It is shown
that absorption cooling air compressor system 100 is comprised of
air inlet filter 102, H-per filter 104, shut off valve 106,
evaporator 108, bypass valve I 110, expansion valve 112, fan 114,
compressor 116, variable frequency drive I (VFD I) 118, variable
frequency drive II (VFD II) 120, oil separator 122, coalescing
filter 124, generator 126, bypass valve II 128, economizer 130,
absorber 132, pump 134, oil cooler 136, condenser 138, after-cooler
140, deep dryer 142, receiver 144, pressure regulation valve 146,
and expansion valve II 148, pressure sensor I 150, temperature
sensor I 152, temperature sensor II 154, liquid level sensor I 156,
liquid level sensor II 158, temperature sensor III 160, pressure
sensor II 162, and temperature sensor IV 164.
[0068] Absorption cooling air compressor system 100 is comprised of
an integrated absorption air compressor system. In the embodiment
illustrated in FIG. 1, air that enters absorption cooling air
compressor system 100 first enters air inlet filter 102, a medium
grade filter configured upstream of H-per filter 104 and configured
to remove mechanical dirt from the incoming air stream. (In other
embodiments, air inlet filter 102 may be a filter of a differing
grade). In the embodiment shown in the Figure, the entering air
then continues along the airflow line to H-per filter 104, a high
performance filter that also removes dirt and particles from the
airstream and is configured downstream of air inlet filter 102 on
the airflow line. The particular type and use of the H-per filter
selected is dependent on the types of applications with which
absorption cooling air compressor system 100 is used. While
illustrated in the embodiment in FIG. 1, H-per filter 104 is not
included in all embodiments. Generally, H-per filter 104 is
included in absorption cooling air compressor system 100 in
applications in which very dry air is needed such as for products
in the pharmaceutical industry. In the illustrated embodiment, air
filtered by H-per filter 104 proceeds to shut-off valve 106.
Shut-off valve 106 is configured on the airflow line of the
absorption system upstream of evaporator 108. Valve 106 does not
let air at a temperature at or lower than 0.degree. C. (adjustable)
enter into the absorption system. It is configured to remain open
to let air that is at a temperature above 0.degree. C. enter
evaporator 108 and continue through the absorption system. Filters
102 and 104 and evaporator 108 function to clean and cool the air
so that it is moisture-free before it enters the compressor. Air
that passes through shut-off valve 106 enters into evaporator 108
and into the absorption system. Air that does not enter the
absorption system continues through the air compressor system
airflow line by bypassing evaporator 108 through bypass valve I 110
and continues on to compressor 116.
[0069] In the illustrated embodiment, supply fan 114 is located on
the airflow line downstream of evaporator 108. It functions to pull
outside air into the system through air inlet filter 102 and H-per
filter 104. Notably, supply fan 114 is not included such as in (but
not limited to) embodiments that do not include an H-per filter. In
embodiments in which the supply fan is included as part of the
configuration like that shown in FIG. 1, the fan may also be
equipped with at least one variable frequency drive (such as VFD I
118 shown here). VFD I 118 controls the fan speed so that the inlet
pressure set point is zero or has a slightly positive pressure. The
pressure set point is measured by pressure sensor I 150. In yet
other embodiments, however, VFD I 118 is not included. An example
of a situation in which VFDs are not included as part of the
configuration of absorption cooling air compressor system 100 (but
is not limited to this example) include when the compressor has a
constant and high load or when the compressor is not configured
with a VFD. In the embodiment presented in FIG. 1, compressor 116
is configured in connection with VFD II 120. The configuration
illustrated in the FIG. 1s the most energy efficient and best
controls the air humidity of the compressed air. When included in
the embodiment, variable frequency drive 120 is modulated to
maintain the pressure set point as measured by pressure sensor I
150. The continuous modulation of the speed results in a lower air
pressure and significant compressor energy savings.
[0070] As shown in the illustration in FIG. 1, compressor 116 is a
lubricant injected compressor and is thus connected on the air
compression system airflow line in communication with an oil cycle
system comprising oil separator 122, oil cooler 136, and also
involves generator 126. Oil cooler 136 is configured in connection
with compressor 116 and generator 126 and functions to cool the oil
temperature of oil from the compressor to below its set point. In
an embodiment, oil cooler 136 is a forced air cooler, while in
other embodiments it may be a water cooler, or other type of heat
exchanger. Oil cooler 136 can be controlled via on/off control or
speed modulation. In the embodiment illustrated in FIG. 1, oil
separator 122 is configured on the air compressor airflow line
downstream of compressor 116 and upstream of coalescing filter 124.
As part of the oil cycle, it functions to separate oil from the
airstream. Oil that is separated out by oil separator 122 is
returned to oil cooler 136. Compressor 116 is configured to
increase the air pressure so that it reaches the level required to
enable air compressor system 100 to provide the amount of air
required. In some embodiments, compressor 116 is a constant speed
compressor that is turned on and off based on the pressure set
point. This pressure set point is measured by pressure sensor II
162. In other embodiments, compressor 116 may be a multiple piston
compressor controlled to maintain the required air pressure level
based on measurements collected by air pressure sensor I 150. In
embodiments in which compressor 116 is not lubricant injected, oil
cooler 136 and oil separator 122 are not needed as part of the
configuration of system 100.
[0071] In the illustration, coalescing filter 124 is configured on
the compressor airflow line between oil separator 122 and generator
126 and is configured to remove lubricant from the compressed air
stream. In other embodiments, especially those in which compressor
116 is not lubricant injected, coalescing filter 124 may not be
included in the configuration of system 100. As shown in the
illustration in FIG. 1, air exiting the compressor continues along
the air compressor system airflow line to after-cooler 140 by
bypassing generator 126 via bypass valve II 128. The valve is
controlled by the temperature set point of generator 126.
Temperature sensor II 154 is configured inside of generator 126 and
determines this set point.
[0072] In the illustrated embodiment, after-cooler 140 is
configured on the air compressor airflow line between generator 126
and deep dryer 142. The after-cooler functions to cool air that has
been compressed to the desired level. Although the embodiment
illustrated in FIG. 1 includes deep dryer 142, said deep dryer is
not necessary in all embodiments of absorption cooling air
compressor system 100. When included in the system, deep dryer 142
is configured on the airflow line between after-cooler 140 and
receiver 144. It functions to remove vapor from the compressed air
as needed and is typically used in applications in which system 100
needs to produce very dry air. Deep dryer 142 can cool the
compressed air to as low as 5.degree. C. (adjustable). At this low
temperature, the compressed air contains almost no moisture. In the
illustration in the Fig., temperature sensor III 160 is configured
downstream of deep dryer 142 on the airflow line and is configured
to measure the temperature of the air stream after air exits dryer
142. Receiver 144 is configured downstream of after-cooler 140 (and
in some embodiments downstream of the deep dryer) and functions as
a reservoir for storing the air. Pressure sensor II 162 is
configured in communication with receiver 144 and measures the
pressure of the airstream. Air exiting system 100 goes through
pressure regulation valve 146. Valve 146 is configured downstream
of receiver 144 and regulates the amount of air delivered to the
end users.
[0073] Air that enters system 100 that is at a temperature above
5.degree. C. enters evaporator 108 and continues through the
absorption system before it goes through the air compressor system.
The absorption system cycle of system 100 comprises evaporator 108,
absorber 132, pump 134, economizer 130, generator 126, and
condenser 138. The absorption system also comprises a plurality of
expansion valves and liquid and temperature sensors. Incoming air
that is allowed to enter into evaporator 108 (by valve 106) is
cooled to about 5.degree. C. (adjustable) in order to ensure that
it has a high density and low moisture content. In the illustrated
embodiment, evaporator 108 is located on the airflow line
downstream of shut-off valve 106 and air filters 102 and 104.
Absorber 132 is configured in connection along the absorption cycle
with evaporator 108. Water vaporized in the economizer proceeds to
absorber 132 where it mixes with an absorbent solution (for example
LiBr). In absorber 132, the weak solution absorbs steam to form a
strong solution. This strong solution is then pumped into
economizer 130 and generator 126 by pump 134. Pump 134 is
configured in communication with absorber 132 and economizer 130.
It primarily functions to recirculate the strong solution from
absorber 132 to generator 126. The speed and on/off status of pump
134 is determined by the liquid level in absorber 132. This liquid
level is measured by liquid level sensor 158 which in FIG. 1 is
located inside absorber 132.
[0074] Economizer 130 is configured on the absorption cycle in
communication with absorber 132 and generator 126 and is operable
to recover heat from said weak solution. The heat recovery reduces
the liquid circulation and improves the operating performance of
absorber 132. Generator 126 is configured on the absorption cycle
line in communication with economizer 130. The generator generates
steam as well as a weak absorbent solution from the high
temperature air and oil streams (mixture of LiBr and H.sub.2O).
Generator 126 also reduces the temperature of the compressed air
and oil. The weakened LiBr solution then cycles back through
economizer 130 and absorber 132 while the generated steam is passed
through condenser 138. Condenser 138 cools the steam to the
temperature setpoint determined by temperature sensor IV 164. The
condensed steam then cycles through deep dryer 142 (when included
in the embodiment of system 100) after passing through expansion
valve 2 148, or goes to evaporator 108 after passing through
expansion valve 112. The expansion valves are configured on the
absorption cycle line in communication with condenser 138 and
lowers the pressure of the liquid produced from the condenser.
Expansion valve 112 is configured to maintain the supply air
temperature at a set point of 5.degree. C. (adjustable).
[0075] It will be apparent to those skilled in the art that various
modifications can be made in the system for compressor air without
departing from the scope or spirit of the given embodiment. Other
embodiments will be apparent to those skilled in the art from
consideration of the specification and practice of the disclosure
of this application.
* * * * *