EP4652417A1

EP4652417A1 - Compressor or vacuum pump system and method for compressing gas and cooling a medium

Info

Publication number: EP4652417A1
Application number: EP24701066.3A
Authority: EP
Inventors: Florian Jean Pierre DANVIN
Original assignee: Atlas Copco Airpower NV
Current assignee: Atlas Copco Airpower NV
Priority date: 2023-01-18
Filing date: 2024-01-11
Publication date: 2025-11-26
Also published as: CN118361867A; BE1031266A1; CN221724619U; BE1031266B1; WO2024154022A1

Abstract

Compressor or vacuum pump system with a compressor or vacuum pump device (2) having a compressor or vacuum pump element (3) with an outlet (4) connected to a discharge line (5), wherein the compressor or vacuum pump system (1) includes an adsorption chiller (9) having an evaporator (10), a condenser (11) and at least two vessels (12A,12B), wherein the adsorption chiller (9) is configured to circulate a refrigerant (14), wherein through the condenser (11) passes a first fluid line (18) for a first fluid to condense the refrigerant (14), wherein through a second vessel (12B) passes a second fluid line (20) for a second fluid to heat and regenerate the desiccant (13) in the second vessel (12B), and wherein through the evaporator (10) passes a medium line (16) for a medium to be cooled by the refrigerant to evaporate the refrigerant (14), characterized in that the aforementioned discharge line (5) forms the second fluid line (20).

Description

COMPRESSOR OR VACUUM PUMP SYSTEM AND METHOD FOR COMPRESSING GAS AND COOLING A MEDIUM.

The present invention relates to a compressor or vacuum pump system.

More particularly, the invention relates to a compressor system for producing compressed gas or a vacuum pump system for creating a vacuum, provided with an adsorption chiller that converts developed heat from the compressor or vacuum pump system, respectively, into cooling energy.

A traditional compressor or vacuum pump system typically includes one or more compressor or vacuum pump elements, often followed by an aftercooler or intercooler. Heat from these compressor or vacuum pump elements is dissipated in the chillers and transferred to the adsorption chiller.

Traditionally, an adsorption chiller is internally equipped with two vessels containing desiccant or a dehydrating agent, an evaporator, a condenser and an internal closed refrigeration circuit.

The refrigerant in this refrigeration circuit, usually water, circulates through the evaporator, condenser and two vessels in which the refrigerant can alternately be adsorbed by the desiccant or regenerate the desiccant, sometimes called desorption.

The condenser is contained in a first water line of the adsorption chiller, with water initially at a first temperature. This first water line is also passed through the vessel that will adsorb refrigerant at that time.

This water in the first water line is cooled with an ambient temperature cooling medium, so the first temperature will approach the ambient temperature, at least just after cooling this water. Afterwards, when passing through the adsorption chiller, the temperature of this water will increase by absorbing adsorption heat.

A second water line is connected to the aforementioned coolers of the compressor system and accordingly transports water at a second temperature higher than the first temperature. This second water line is passed through the vessel in which the desiccant will be regenerated at that time. The evaporator is included in a cooled water circuit, whose developed cooling capacity can be used to absorb heat from an external system or consumer, for air treatment or other similar purposes.

The first and second water lines, as well as the cooled water circuit, are completely separated from the internal cooling circuit of the adsorption chiller, so the water in these lines never comes into direct contact with the refrigerant. Heat exchange is done with closed heat exchangers.

A disadvantage of these compressor or vacuum pump systems is that the temperature of the water is usually limited to 90°C, to prevent steam generation resulting in corrosion of the first water line, the second water line and/or the cooled water circuit.

Another disadvantage of these types of known systems is that the complex heat transfer requires several water pumps and buffer tanks, with the compressor or vacuum pump system typically water-cooled.

Application with an air-cooled compressor or vacuum pump element is difficult, if not impossible.

The present invention seeks to address the aforementioned and/or other disadvantages.

For this purpose, the invention relates to a compressor or vacuum pump system provided with a compressor or vacuum pump device, respectively, provided with at least one compressor or vacuum pump element, respectively, having an outlet for compressed gas connected to a discharge line, wherein the compressor or vacuum pump system is further provided with an adsorption chiller having an evaporator, a condenser and at least two vessels filled with desiccant, wherein the adsorption chiller is configured to circulate a refrigerant through the evaporator, condenser and two vessels, wherein through the condenser passes a first fluid line providing a first fluid at initially a first temperature to condense the refrigerant, which first fluid line also passes through a first of said vessels to cool the desiccant in the first vessel, wherein through a second vessel passes a second fluid line for a second fluid at initially a second temperature to heat and regenerate the desiccant in the second vessel, the second temperature being higher than the first temperature, wherein through the evaporator passes a medium line for a medium to be cooled by the refrigerant to evaporate the refrigerant, characterized by the fact that the aforementioned discharge line constitutes the second fluid line.

As hot compressed gas coming from the compressor device can now be used as a second fluid in the second fluid line, water pumps and buffer tanks are no longer necessary and the system can also be applied with air-cooled compressor elements.

Another advantage of using compressed gas instead of water as the second fluid is that the temperature of the compressed gas in the second fluid line can be higher than 90°C since there is no risk of corrosion of the compressor elements or components due to steam generation. The higher temperature favors the time required for regeneration of the desiccant in the second vessel.

Another advantage is that the load on the coolers of the compressor elements is reduced, allowing these coolers and consequently the entire compressor system to be more compact.

In a preferred embodiment of compressor or vacuum pump system according to the invention, the discharge line leads to a cooler for cooling the compressed gas, and preferably an outlet line for cooled compressed gas departs from said cooler wherein said outlet line serves as said first fluid line.

This has the advantage that there is also no need for water pumps and buffer tanks in the first fluid line, and this keeps the system simple with a minimum of parts. The invention also relates to a method for cooling a medium with an adsorption chiller using heat of compression, using a compressor or vacuum pump system according to the invention, and the method comprising using the compressed gas as the fluid for the second fluid line.

The invention also further relates to a method for compressing gas and cooling a medium, wherein the gas is compressed by means of a compressor or vacuum pump system provided with a compressor or vacuum pump device, respectively, wherein the medium is cooled by means of a refrigerant in an adsorption chiller, wherein the refrigerant in the adsorption chiller is circulated through an evaporator, a condenser and at least two vessels filled with desiccant, wherein the refrigerant is condensed in the condenser by means of a first heat exchange with a first fluid at initially a first temperature, wherein the desiccant in a first vessel of the aforementioned vessels is also cooled by means of the first fluid, wherein the desiccant is heated and regenerated in a second vessel of the aforementioned vessels by means of a second heat exchange with a second fluid at initially a second temperature, the second temperature being higher than the aforementioned first temperature, wherein the refrigerant in the evaporator is evaporated by means of a third heat exchange with the medium, with the distinguishing feature of using the compressed gas as the second fluid.

In a preferred embodiment of the method according to the invention, the compressed gas is cooled after the second heat exchange, and preferably cooled to the first temperature and used as the first fluid. Obviously, these methods enjoy the same advantages as the corresponding embodiments of the compressor or vacuum pump system according to the invention as described hereabove.

Having the understanding to better demonstrate the features of the invention, hereafter, as an example without any limiting character, a preferred embodiment of a compressor or vacuum system according to the invention and the method applied thereto is described, with reference to the accompanying drawings, wherein:

Figure 1 schematically depicts an existing compressor system;

Figure 2 schematically depicts a compressor system according to the invention.

In the description of the figures, the invention is further explained in detail on the basis of a compressor system. Obviously, this could also be a vacuum pump system.

Figure 1 schematically shows an already existing compressor system 1 equipped with a compressor device 2 with, in this case, two compressor elements 3 connected in series for the production of compressed gas.

The compressor elements 3 are provided with an outlet 4 for compressed gas connected to a discharge line 5, which leads to a cooler 6 for cooling the compressed gas. From the last cooler 6 departs an exhaust line 7 for refrigerated compressed gas.

The compressor system 1 is further provided with a casing 8 that houses both an adsorption chiller 9 and the compressor device 2.

The adsorption chiller 9 converts heat from the compressed gas into cooling capacity and includes an evaporator 10, a condenser 11 and two vessels 12A, 12B filled with desiccant 13, although this could alternatively be more than two vessels. In vessels 12A, 12B, the desiccant 13 will alternately adsorb a refrigerant 14 and be regenerated.

The desiccant 13 here is silica gel and the coolant 14 water, although zeolite or activated carbon is also possible as a desiccant, in the latter case the coolant being, for example, ammonia or ethanol.

The refrigerant 14 circulates through the evaporator 10, the condenser 11 and the two vessels 12A, 12B containing desiccant 13. The circulation of refrigerant 14 is controlled by four valves 15A, 15B, 15C and 15D that allow or block the inflow or outflow of refrigerant 14 to or from the condenser 11 and evaporator 10.

A medium line 16 flows through the evaporator 10. In this medium line 16, a medium, for example water, in the evaporator 10 transfers heat to the refrigerant 14. The cooling capacity of the cooled medium can then be used elsewhere in a consumer 17 or system, such as in an air treatment system.

Through the condenser 11 and a first vessel 12A in which the desiccant 13 will adsorb the refrigerant 14 is passed a first fluid line 18 containing water at initially a first temperature. The cooling capacity of this water is used to allow the desiccant 13 to better absorb refrigerant 14 in the first vessel 12A, after which the water is further heated in the condenser 11 and then cooled in a cooling tower 19 or the like.

If in this cooling tower 19 a medium is used at ambient temperature, which will often be the case in practice, the aforementioned first temperature will approach the ambient temperature, at least when the water leaves the cooling tower 19.

A second fluid line 20 containing water at initially a second temperature was passed through the second vessel 12B. This second temperature is higher than the aforementioned first temperature. This second fluid line 20 is also passed through the coolers 6 of the compressor elements 3. Heat from the coolers 6 is transferred to the water of the second fluid line 20 and this heat will be used in the second vessel 12B to dry or regenerate the desiccant 13. At no time does the refrigerant 14 come into fluid contact with the medium of the medium line 16 or with the water of the first fluid line 18 or second fluid line 20.

The adsorption cycle works traditionally with four phases, namely a preheating phase, a regeneration phase, a pre-cooling phase and an adsorption phase.

In the preheating phase, all valves 15A, 15B, 15C and 15D are closed. The desiccant 13 in the second vessel 12B is heated, causing the pressure in the second vessel 12B to increase due to desorption of the refrigerant 14. The preheating phase stops when the pressure in the second vessel 12B becomes equal to the pressure in the condenser 11 .

At the start of the regeneration phase, the valves 15A and 15D open, allowing the desiccant 13 in the second vessel 12B to heat virtually isobarically until the maximum temperature in the second vessel 12B is reached. The desiccant 13 in the second vessel 12B is now fully regenerated or dried. Evaporated refrigerant 14 is collected and condensed in the condenser 11. Liquid refrigerant 14 is returned to the evaporator 10 (not shown in this diagram).

Before the start of the pre-cooling phase, all valves 15A, 15B, 15C and 15D are closed. The first vessel 12A is hereby cooled until its pressure equals the pressure in the evaporator 10.

Obviously, the pre-cooling phase of the first vessel 12A coincides with the pre-heating phase of the second vessel 12B.

Finally, valves 15A and 15D are opened after which the adsorption phase is started in the first vessel 12A. The desiccant 13 in the first vessel 12A undergoes isobaric cooling and the refrigerant 14 will evaporate in the evaporator 10, with the evaporated refrigerant 14 being adsorbed onto the desiccant 13 in the first vessel 12A. During this adsorption phase, medium in the medium line 16 is cooled by evaporating the refrigerant 14, after which the cooling capacity in the cooled medium can be utilized in the consumer 17. Obviously, the adsorption phase in the first vessel 12A coincides with the regeneration phase in the second vessel 12B.

It should also be clear that the desiccant 13 in the first vessel 12A and second vessel 12B will successively pass through all these four stages in the adsorption cycle, alternately adsorbing refrigerant 14 and being regenerated.

The driving force in this cycle is the evaporation of the refrigerant 14.

The compressor system 1 according to the invention, as shown in Figure 2, the aforementioned second fluid line 20 is formed by the aforementioned discharge line 5.

Also in this example, the compressor device 2 comprises two compressor elements 3 connected in series, wherein a discharge line 5 is connected to the outlet 4 of each compressor element 3 and wherein each discharge line 5 serves as a second fluid line 20.

Therefore, the fluid in this second discharge line 5 is high-temperature compressed gas coming from the compressor elements 3. This hot compressed gas is used to regenerate or dry the desiccant 13, in contrast to conventional systems where high-temperature water from coolers 6 is used to regenerate the desiccant 13.

The use of compressed gas allows higher regeneration temperatures than when using water. After all, there is no danger of steam formation. There is also no need for water pumps and buffer tanks in the second fluid line 20 whereby the invention is also easily applicable to air-cooled compressor systems 1.

The fluid in the first fluid line 18 can thereby be a liquid, such as water, as in a conventional compressor system 1 or compressed gas, coming from an exhaust line 7 of the cooler 6 that serves as the first fluid line 18.

In the example of Figure 2, each aforementioned second fluid line 20 extends only partially through a well-defined portion of the second vessel 12B. Alternatively, any second fluid line 20 could also extend through the entire vessel 12B. The present invention is by no means limited to the embodiments described as examples and shown in the figures, but a compressor or vacuum system according to the invention can be accomplished in a variety of shapes and sizes without going outside the scope of the invention as defined in the claims.

Claims

1. A compressor or vacuum pump system equipped with a compressor or vacuum pump device (2) equipped with at least one compressor or vacuum pump element (3) with an outlet (4) for compressed gas connected to a discharge line (5), respectively, wherein the compressor or vacuum pump system (1) is further provided with an adsorption chiller (9) having an evaporator (10), a condenser (11) and at least two vessels (12A.12B) filled with desiccant (13), wherein the adsorption chiller (9) is configured to circulate a refrigerant (14) through the evaporator (10), condenser (11) and two vessels (12A.12B), wherein through the condenser (11) passes a first fluid line (18) for a first fluid at initially a first temperature to condense the refrigerant (14), which first fluid line (18) also passes through a first vessel (12A) of the aforementioned vessels (12A, 12B) to cool the desiccant (13) in the first vessel (12A), wherein through a second vessel (12B) of the aforementioned vessels (12A, 12B) passes a second fluid line (20) for a second fluid at initially a second temperature to heat and regenerate the desiccant (13) in the second vessel (12B), wherein the second temperature is higher than the aforementioned first temperature, and wherein through the evaporator (10) passes a medium line (16) for a medium to be cooled by the refrigerant to evaporate the refrigerant (14), characterized in that the aforementioned discharge line (5) forms the second fluid line (20).

2. The compressor or vacuum pump system according to claim 1 , characterized in that the discharge line (5) leads to a cooler (6) for cooling the compressed gas.

3. The compressor or vacuum pump system according to claim 2, characterized in that from the cooler (6) an outlet line (7) departs for refrigerated compressed gas wherein said outlet line (7) serves as said first fluid line (18).

4. The compressor or vacuum pump system according to claim 1 , characterized in that in the first fluid line (18) flows a liquid such as water.

5. The compressor or vacuum pump system according to any one of the preceding claims, characterized in that the compressor or vacuum pump device (2) comprises two or more compressor or vacuum pump elements (3) connected in series, respectively, wherein the outlet (4) of each compressor or vacuum pump element (3) is connected to a discharge line (5), each discharge line (5) serving as a second fluid line (20).

6. The compressor or vacuum pump system according to claim 5, characterized in that each aforesaid second fluid line (20) extends through the entire second vessel (12B) or that each second fluid line (20) extends only through a well-defined portion of the second vessel (12B).

7. The compressor or vacuum pump system according to any one of the preceding claims, characterized in that the adsorption chiller is provided with more than two vessels filled with desiccant (13).

8. The compressor or vacuum pump system according to any one of the preceding claims, characterized in that the desiccant (13) is silica gel or zeolite wherein the refrigerant (14) is water; or the desiccant (13) is activated carbon.

9. The compressor or vacuum pump system according to any one of the preceding claims, characterized in that the compressor or vacuum pump system (1) is provided with a casing (8) in which both the compressor or vacuum pump system (2) and the adsorption chiller (9) are housed, respectively.

10. A method for cooling a medium by means of an adsorption chiller (9) using heat of compression, characterized in that the method uses a compressor or vacuum pump system (1) according to any one of the preceding claims wherein the method involves using the compressed gas as the second fluid for the second fluid line (20).

11. A method for compressing gas and cooling a medium, wherein the gas is compressed by means of a compressor or vacuum pump system (1) equipped with a compressor or vacuum pump device (2), respectively, wherein the medium is cooled by means of a refrigerant (14) in an adsorption chiller (9), wherein the refrigerant (14) is circulated in the adsorption chiller (9) through an evaporator (10), a condenser (11) and at least two vessels (12A, 12B) filled with desiccant (13), wherein the refrigerant (14) is condensed in the condenser (11) by means of a first heat exchange with a first fluid at initially a first temperature, wherein the desiccant (13) in a first vessel (12A) of the aforementioned vessels (12A, 12B) is also cooled by means of the first fluid, wherein the desiccant (13) is heated and regenerated in a second vessel (12B) of the aforementioned vessels (12A, 12B) by means of a second heat exchange with a second fluid at initially a second temperature, the second temperature being higher than the aforementioned first temperature, wherein the refrigerant (14) is evaporated in the evaporator (10) by means of a third heat exchange with the medium, characterized in that the compressed gas is used as the second fluid.

12. The method according to claim 11 , characterized in that the compressed gas is cooled after the second heat exchange.

13. The method according to claim 12, characterized in that the compressed gas is cooled to the first temperature after the second heat exchange and used as the first fluid.

14. The method according to claim 11, characterized in that a liquid such as water is used as the first fluid.

15. The method according to any one of the preceding claims 11 to 14, characterized in that the compressor or vacuum pump device (2) comprises two or more compressor or vacuum pump elements (3) connected in series, respectively, wherein the gas compressed by each of these compressor or vacuum pump elements (3) is used as a second fluid.