Adsorption dryer with intelligent purge control

Abstract

The invention relates to an adsorption dryer system for processing gases such as air, in particular compressed gases, comprising a regulating flow control valve, wherein an operating parameter of the regulating flow control valve, in particular a flow rate through the flow control valve, is set in real time depending on a system parameter. The invention also relates to a method for operating such an adsorption dryer system.

Description

[0001] Adsorption Dryer with Intelligent purge control

[0002] The invention relates to an adsorption dryer system for processing gases as well as to a method for the operation of an adsorption dryer system.

[0003] Fluid flows (gaseous or fluid media) through an opening in a valve or orifice vary based on current temperature and pressure conditions, which are continuously changing in a compressed gas system. The typical way purge flows are controlled is with the use of a fixed orifice and a hand operated valve, via which the pressure can be set so that the desired purge flow flows through the orifice to achieve the desired purge flow rate.

[0004] However, the desired flow rate is only accurate if conditions (pressure and temperature of the medium) are the exact same as when the initial setting was made.

[0005] Typical adsorption dryers use a combination of a hand operated control valve in combination with a fixed diameter orifice to set the desired gas flow rate. For this purpose, the following components are provided (behind one another in the flow direction):

[0006] 1. Purge Line Inlet

[0007] 2. Control Valve

[0008] 3. Pressure Gauge

[0009] 4. Orifice

[0010] 5. Purge Line outlet

[0011] Applications are also known which do not comprise a pressure gauge, the setting then being carried out by the number of turns of the valve.

[0012] An option to vary the control pressure of the control valve on the basis of the current operating conditions of the system is not provided. The following equation illustrates the relationships for the flow through a valve,

[0013] The parameters signify:

[0014] Q = Purge gas flow rate

[0015] Cl = Flow constant

[0016] Cv = Valve flow coefficient

[0017] P = Absolute inlet pressure

[0018] S.G. = Specific gravity of medium

[0019] T = Absolute temperature of the gas

[0020] The equation is only to be understood as an example, it is not generally valid and in this form possibly does not hold for specific setups.

[0021] It remains the case, however, that the purge flow rate varies relative to the initial setting as the temperature and pressure of the system change, which can lead to an excessively high purge flow rate and thus to higher energy consumption or conversely to an excessively low purge flow rate and thus to diminished system performance.

[0022] A further disadvantage of this system is that, during the use of purge gases in different parts of the operating cycle, different gas flow rates would ideally have to be set, but instead the same are used.

[0023] An example of this is an external purge adsorption dryer, where the purge air is used for both the heating and for the cooling cycle of the regeneration cycle. It comprises the following components behind one another in the flow direction:

[0024] 1. Purge Line Inlet

[0025] 2. Control Valve

[0026] 3. Pressure Gauge 4. Orifice

[0027] 5. Heater

[0028] 6. Purge Line outlet

[0029] During the heating portion of the regeneration cycle, purge air is directed through this system and over a heater to regenerate the adsorbate. During the cooling cycle, the adsorbent material must be cooled ready for the next drying cycle, wherein the purge air is directed through the same orifice, but this time without heating. Based on the system setup, the ideal purge flow rates during the heating and cooling cycles are not the same, but with this typical setup there is no way to alter the flow.

[0030] The objective underlying the invention is to propose an improved adsorption dryer system and an improved method for operating a such an adsorption dryer system.

[0031] The objective is solved by the adsorption dryer system according to claim 1 and the method according to claim 13.

[0032] The invention relates to an adsorption dryer system for processing gases such as air, in particular compressed gases, comprising a regulating flow control valve, wherein an operating parameter of the regulating flow control valve, in particular a flow rate through the flow control valve, is set in real time depending on a system parameter.

[0033] The operating parameter may in particular be a flow rate through the regulating flow control valve, or the operating parameter may (directly or indirectly) affect the flow rate through the regulating flow control valve. The operating parameter may be an opening width of the flow control valve, which may affect or adjust the flow rate of the regulating flow control valve. Accordingly, the purge control valve is able to adapt current operating conditions in order to ensure that the necessary quantity of purge flow is used for the regeneration.

[0034] The invention enables variation of the flow rates during different phases of the regeneration cycle (e.g. heating and cooling), which is impossible with the hand operated valve and the arrangement with a fixed orifice.

[0035] Some general embodiments of the invention can be summarized as follows, wherein specific embodiments of the invention are given in the sub-claims.

[0036] A preferred variant of embodiment provides for the use of an electrically actuated ball valve for control of the purge gas flow, so representing said regulating flow control valve. Alternatively, use can however also be made of the following alternatives, but is not limited thereto:

[0037] Pneumatically actuated proportional valve

[0038] Electronically / pneumatically actuated proportional butterfly valves

[0039] Control globe valves

[0040] Linear control valve

[0041] Series of on / off valves with different sized orifices

[0042] For control logic to monitor current performance of regeneration and to determine the correct purge gas flow rate, temperature sensors and pressure sensors are strategically placed on the unit in various locations to determine as accurately as possible how far the regeneration process has advanced and how much more or less purge will be required. Alternative sensors, which can be used for support and for control, are as follows (list not exhaustive):

[0043] Flow meters

[0044] Pressure dewpoint sensors

[0045] Humidity sensors Essential knowledge of the invention consists in the use of a regulating purge control valve (proportional) - representing said regulating flow control valve - in an adsorption dryer. Variable purge rates are possible based on current operating and regeneration performance. Also new and advantageous is the intelligent operating logic, which allows for enhanced performance in varying operating conditions.

[0046] The advantages of the invention are to be found in the integration of additional intelligent logic and the precise purge flow control and in particular the self-monitoring of the unit performance. This guarantees that regeneration is achieved in the most economical manner, while maintaining guaranteed performance.

[0047] By replacing the typical hand operated valve and using an electronically controlled flow valve with logic and sensor system to determine the correct opening rate required to achieve the desired flow rate, the system is protected from both the use of excessive purge consumption for energy saving and under purge consumption to maintain system performance.

[0048] The invention is further characterized by the features disclosed in the subclaims.

[0049] According to an embodiment of the invention, the adsorption dryer system further comprises an inlet, which in particular is a purge line inlet, and an outlet, which in particular is a purge line outlet, wherein the regulating flow control valve is arranged between the inlet and the outlet.

[0050] According to a further embodiment of the invention, the operating parameter is set to adjust a purge flow rate.

[0051] According to a further embodiment of the invention, the adsorption dryer system further comprises a programmable logic controller, operatively connected to the regulating flow control valve. According to a further embodiment of the invention, the programmable logic controller is configured to control the regulating flow control valve based on a programmed logic. By that, a precise control of the purge flow rate during different phases of a regeneration cycle can be established.

[0052] The proposed invention is based on the use of a regulating flow control valve, which can be controlled via a programmable logic controller (PLC in the following) with programmed logic, in order to determine the correct opening rate of the valve for a precise purge flow control based on the flow demand of the current regeneration cycle.

[0053] The function of a regulating flow control valve in the purge line of an adsorption dryer is to guarantee precise purge rates based on the actual operating conditions of the system regarding real-time system pressures and temperatures, without the dryer having to be continuously monitored by a human and a manually operated valve having to be adjusted. For example, the flow control valve thus has to be opened more at a lower operating pressure to achieve the desired flow rate, whereas the flow control valve has to be opened less at a higher operating pressure.

[0054] A further advantage of the invention is that the purge flow valve can operate at different flow rates during the heating and cooling portions of the regeneration cycle. Heat balance calculations show that these values are not equal.

[0055] Lastly, the regulating flow control valve allows for operating logic to be programmed into the PLC to monitor the current conditions of the regenerating adsorbent bed and to alter the flow rate based on sensors in the system, in order to achieve the most economical purge flow rate setting in both the heating and cooling stages of the regeneration cycle and to limit unnecessary purge consumption, while still maintaining the desired performance by the end user. According to a further embodiment of the invention, the adsorption dryer system further comprises at least one sensor, which is configured to determine a measurement parameter representing the system parameter.

[0056] According to a further embodiment of the invention, the measurement parameter in particular is a pressure and / or temperature of the system.

[0057] According to a further embodiment of the invention, the at least one sensor is configured to determine the measurement parameter in real time. In particular, the at least one sensor can be configured to monitor real time data of conditions to adjust a purge flow rate to optimize a purge consumption used by the system during different phases of the regeneration cycle.

[0058] According to a further embodiment of the invention, the programmable logic controller is configured to control the regulating flow control valve based on the measurement parameter. By that, the purge flow rate can be optimized for different regeneration phases, including heating and cooling cycles. Due to the real time monitoring of the measurement parameter (system parameter) by using the at least one sensor, a online control and adaption of the purge flow rate can be established.

[0059] According to a further embodiment of the invention, the at least one sensor comprises at least one of the following: a temperature sensor, a pressure sensor, a flow sensor, a pressure dewpoint sensor, a humidity sensor. By use of said at least one sensor and the measurement parameter (system parameter) determined with the at least one sensor, the programmable logic controller can utilize the measurement parameter (system parameter) to control the purge flow rate. The at least one sensor and the programmable logic controller are connected in terms of data transmission, which may be utilized wireless or non-wireless (wire-based).

[0060] According to a further embodiment of the invention, the programmable logic controller is configured to control the regulating flow control valve during different operating conditions of the system, in particular during different phases of regeneration, including heating and cooling.

[0061] According to a further embodiment of the invention, the programmable logic controller is configured to control the regulating flow control valve with the premise to optimize energy efficiency and system performance.

[0062] As stated above, the objective of the invention is also solved by a method according to claim 13.

[0063] Therefore, the invention also relates to a method for operating an adsorption dryer system for processing gases such as air, in particular compressed gases, comprising a regulating flow control valve, with the process steps determination of a system parameter, setting of an operating parameter of the regulating flow control valve, in particular a flow rate through the regulating flow control valve, depending on the determined system parameter in real time.

[0064] According to an embodiment of the method according to the invention, the adsorption dryer system further comprises an inlet, which in particular is a purge line inlet, and an outlet, which in particular is a purge line outlet, wherein the regulating flow control valve is arranged between the inlet and the outlet.

[0065] According to an embodiment of the method according to the invention, the operating parameter is set to adjust a purge flow rate.

[0066] According to an embodiment of the method according to the invention, the adsorption dryer system further comprises a programmable logic controller, operatively connected to the regulating flow control valve. According to an embodiment of the method according to the invention, the programmable logic controller controls the regulating flow control valve based on a programmed logic.

[0067] According to an embodiment of the method according to the invention, the adsorption dryer system further comprises at least one sensor, which determines a measurement parameter representing the system parameter.

[0068] According to an embodiment of the method according to the invention, the measurement parameter is a pressure and / or temperature of the system.

[0069] According to an embodiment of the method according to the invention, the at least one sensor determines the measurement parameter in real time.

[0070] According to an embodiment of the method according to the invention, the programmable logic controller controls the regulating flow control valve based on the measurement parameter.

[0071] According to an embodiment of the method according to the invention, the at least one sensor comprises at least one of the following: a temperature sensor, a pressure sensor, a flow sensor, a pressure dewpoint sensor, a humidity sensor.

[0072] According to an embodiment of the method according to the invention, the programmable logic controller controls the regulating flow control valve during different operating conditions of the system, in particular during different phases of regeneration, including heating and cooling.

[0073] According to an embodiment of the method according to the invention, the programmable logic controller to controls the regulating flow control valve with the premise to optimize energy efficiency and system performance. The invention is further explained with the aid of the following figures. They are not to be understood as limiting. They serve solely for a better understanding of the relationships.

[0074] In the figures:

[0075] Fig. 1 : shows a schematic diagram of a dryer according to the prior art,

[0076] Fig. 2: shows a schematic diagram of an external purge dryer according to the prior art,

[0077] Fig. 3: shows a schematic diagram of a heated dryer according to the invention with a programmable logic controller (PLC),

[0078] Fig. 4: shows a representation of a heated dryer with a programmable logic controller.

[0079] Typical adsorption dryers use a combination of a hand operated control valve combined with a fixed diameter orifice for setting the desired gas flow rate. A schematic diagram is shown in fig. 1. The following are shown (behind one another in the flow direction):

[0080] 1. Purge line inlet

[0081] 2. Control valve

[0082] 3. Pressure gauge

[0083] 4. Orifice

[0084] 5. Purge line outlet

[0085] As already stated, the pressure gauge can be dispensed with, the setting then being carried out by the number of turns of the valve wheel.

[0086] As an example of this, fig. 2 shows an external purge adsorption dryer, in which the purge air is used for both the heating and the cooling cycle of the regeneration cycle. Such an adsorption dryer comprises the following components behind one another in the flow direction:

[0087] 1. Purge line inlet

[0088] 2. Control valve

[0089] 3. Pressure gauge

[0090] 4. Orifice 6. Heater

[0091] 5. Purge line outlet

[0092] Fig. 3 shows a schematic diagram of a heated adsorption dryer according to the invention with a programmable logic controller. The components and elements have the following reference numbers:

[0093] The regulating flow control valve or the control valve for the purge air control (regulating purge control valve) is identified with reference number 27 and is arranged between a heater 28 and temperature and pressure sensors 25, 26. Reference numerals 1 (dryer inlet) and 31 (dryer outlet) may be understood as "inlet" and "outlet" in the nomenclature of the claims. Also, other components of above cited table may represent the "inlet" and "outlet". Any component of the adsorption dryer system being arranged upstream (in flow direction of the gas) relative to the regulating flow control valve may represent an "inlet". Any component of the adsorption dryer system being arranged downstream (in flow direction of the gas) relative to the regulating flow control valve 27 may represent an "outlet".

[0094] It is to be noted that the dryer illustrated in figs 3 is only shown for illustrative (not limiting) purposes. The invention is also applicable to adsorption dryers which do not have heaters as shown by reference number 28 of figure 3.

Claims

CLAIMS1. An adsorption dryer system for processing gases such as air, in particular compressed gases, comprising a regulating flow control valve, wherein an operating parameter of the regulating flow control valve, in particular a flow rate through the regulating flow control valve, is set in real time depending on a system parameter.

2. An adsorption dryer system according to claim 1, further comprising an inlet, which in particular is a purge line inlet, and an outlet, which in particular is a purge line outlet, wherein the regulating flow control valve is arranged between the inlet and the outlet.

3. An adsorption dryer system according to one of claim 1 or 2, wherein the operating parameter is set to adjust a purge flow rate.

4. An adsorption dryer system according to any one of claims 1 to 3, further comprising a programmable logic controller, operatively connected to the regulating flow control valve.

5. An adsorption dryer system according to claim 4, wherein the programmable logic controller is configured to control the regulating flow control valve based on a programmed logic.

6. An adsorption dryer system according to any one of claims 1 to 5, further comprising at least one sensor, which is configured to determine a measurement parameter representing the system parameter.

7. An adsorption dryer system according to claim 6, wherein the measurement parameter is a pressure and / or temperature of the system.RECTIFIED SHEET (RULE 91 ) ISA / EP8. An adsorption dryer system according to claim 6 or 7, wherein the at least one sensor is configured to determine the measurement parameter in real time.

9. An adsorption dryer system according to any one of the preceding claims, wherein the programmable logic controller is configured to control the regulating flow control valve based on the measurement parameter.

10. An adsorption dryer system according to any one of the preceding claims, wherein the at least one sensor comprises at least one of the following: a temperature sensor, a pressure sensor, a flow sensor, a pressure dewpoint sensor, a humidity sensor.

11. An adsorption dryer system according to any one of the preceding claims, wherein the programmable logic controller is configured to control the regulating flow control valve during different operating conditions of the system, in particular during different phases of regeneration, including heating and cooling.

12. An adsorption dryer system according to any one of the preceding claims, wherein the programmable logic controller is configured to control the regulating flow control valve with the premise to optimize energy efficiency and system performance.

13. A method for operating an adsorption dryer system for processing gases such as air, in particular compressed gases, comprising a regulating flow control valve, with the process steps determination of a system parameter, setting of an operating parameter of the regulating flow control valve, in particular a flow rate through the regulating flow controlRECTIFIED SHEET (RULE 91 ) ISA / EPvalve, depending on the determined system parameter in real time.

14. A method according to claim 13, wherein the adsorption dryer system further comprises an inlet, which in particular is a purge line inlet, and an outlet, which in particular is a purge line outlet, wherein the regulating flow control valve is arranged between the inlet and the outlet.

15. A method according to one of claims 13 or 14, wherein the operating parameter is set to adjust a purge flow rate.

16. A method according to any one of claims 13 to 15, wherein the adsorption dryer system further comprises a programmable logic controller, operatively connected to the regulating flow control valve.

17. A method according to claim 16, wherein the programmable logic controller controls the regulating flow control valve based on a programmed logic.

18. A method according to any one of claims 13 to 17, wherein the adsorption dryer system further comprises at least one sensor, which determines a measurement parameter representing the system parameter.

19. A method according to claim 18, wherein the measurement parameter is a pressure and / or temperature of the system.

20. A method according to claim 18 or 19, wherein the at least one sensor determines the measurement parameter in real time.

21. A method according to any one of claims 13 to 20, wherein the programmable logic controller controls the regulating flow control valve based on the measurement parameter.RECTIFIED SHEET (RULE 91 ) ISA / EP22. A method according to any one of claims 13 to 21, wherein the at least one sensor comprises at least one of the following: a temperature sensor, a pressure sensor, a flow sensor, a pressure dewpoint sensor, a humidity sensor.

23. A method according to any one of claims 13 to 22, wherein the programmable logic controller controls the regulating flow control valve during different operating conditions of the system, in particular during different phases of regeneration, including heating and cooling.

24. A method according to any one of claims 13 to 23, wherein the programmable logic controller to controls the regulating flow control valve with the premise to optimize energy efficiency and system performance.RECTIFIED SHEET (RULE 91 ) ISA / EP

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