JPH01249125A - Gas drying apparatus - Google Patents

Abstract

PURPOSE: To remarkably decrease the quantity of the dry air required for regeneration by alternately opening and closing a purge valve to alternately pressurize and evacuating the columns under regeneration of a desiccating agent during regeneration and limiting the quantity of the air released from the purge valve. CONSTITUTION: While the column 12 is under a drying cycle, the valve 16 is opened and the valve 18 is closed and the satd. air from an inlet 200 is supplied from the valve 16 to the column 12, where the moisture in the satd. air is absorbed by the desiccating agent. The pressurized desiccating agent is delivered from an outlet 28 through a pipe 24 and a check valve 26. The dry air is partly branched to a pipe 34 and is sent downward in the column 14 through a joint 38, a check valve 42 and a pipe 30. The purge valve 50 is intermittently opened and closed during the regeneration cycle. The pressurization and evacuation are repetitively applied to the column 14 by repetitively opening and closing the purge valve 50 and, as a result thereof, the moisture of the dry air passing the inside of the column 14 is able to be more absorbed with the smaller purge flow rate. The flow of the released dry air is interrupted and the quantity of the dry air necessary for the regeneration of the desiccating agent may be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a gas drying apparatus, and more particularly to a two-unit gas drying apparatus.

Problems to be Solved by the Prior Art and the Invention The presence of moisture in gases causes troublesome problems in many industrial and business fields. In other words, even a slight drop in temperature causes moisture to condense in pipelines and gas tanks, resulting in corrosion, deposits, freezing, and dust adhesion. They can damage instruments and controls and block air lines, creating excessive pressure drops, increasing equipment downtime and shortening its lifespan. Similarly, in the fields of chemistry, food, and metal processing, undesirable oxidation effects occur when air or gas contains moisture. It is also known that in the field of industrial robots, very dry air is required to operate pneumatic systems.

Adsorption drying systems are used to obtain very dry air, air with a dew point below 140 degrees Fahrenheit. In a typical adsorption drying system, drying is performed by two columns filled with desiccant.

In such a two-unit adsorption drying method, air containing moisture is supplied to one column, and dry air is passed through the other column to regenerate the desiccant in that column.

Conventionally, in this regeneration process, a portion of the dried air obtained from one tower used in the drying cycle is passed through another tower, and the moisture contained in the desiccant packed in this tower is absorbed into the dry air. It has been attempted to regenerate the desiccant by Typically, 15% of the dried air from the column used in the drying cycle is used to regenerate the desiccant in the other column. Clearly, this process has the problem of diverting 15% of the drying air obtained to the regeneration of desiccant in other columns rather than its original purpose.

What is desired is a gas drying device that can significantly reduce the amount of drying air required to regenerate the desiccant in the column by more than 15%.

SUMMARY OF THE INVENTION In summary, the present invention comprises two drying towers containing desiccant agents, one in which air is saturated with moisture to be dried, and the other in which air saturated with moisture is to be dried. A two-gas drying device in which dry air is alternately supplied to absorb moisture in the air and regenerate the wet desiccant, and the air used to regenerate the desiccant is released. with a purge valve for
During the regeneration process, the purge valve is alternately opened and closed to alternately pressurize and depressurize the tower in which desiccant regeneration takes place, and to obtain the dew point of the drying air to obtain the amount of air released through the purge valve. Provided is a gas drying device characterized by comprising a purge valve control device that restricts the purge without raising the gas.

The present invention is a two-unit gas drying apparatus consisting of two drying towers, in which each tower is provided with an inlet valve for introducing pressurized saturated air saturated with moisture, and the inlet valve is opened and closed to perform drying. A control means is provided to supply saturated air to only one tower during the cycle, and each tower is supplied with saturated air to be dried and a desiccant that has become moist due to absorption of moisture in the saturated air during the previous drying process. To provide a gas drying device configured to alternately supply dry air for regeneration.

According to another embodiment of the invention, the gas drying device is provided with a regeneration valve associated with each column for introducing drying air into the column during the regeneration cycle, the drying air removing moisture from the desiccant. The desiccant is regenerated. The gas drying apparatus further includes means for alternately opening and closing the regeneration valve so that only one column is supplied with dry air during the regeneration cycle.

According to yet another embodiment of the invention, each column has a purge valve for releasing air used for regeneration of the desiccant to the atmosphere, and the purge valve is alternately opened and closed during the regeneration cycle. Control means are provided for alternately pressurizing and depressurizing the column and restricting the passage of air through the purge valve.

Effect: According to the gas drying device according to the present invention, the layer of air necessary for regenerating the desiccant in the tower can be limited to a small number, and it is possible to increase the proportion of air supplied for plant operation than in the drying tower. .

EXAMPLES The present invention will be described below with reference to the most preferred embodiments, but it is clear that various modifications and changes can be made to the details of the embodiments described below within the spirit and gist of the present invention. Will.

Referring to FIG. 1, the gas drying apparatus 10 includes a pair of towers 12.
and 14. These columns contain a desiccant such as activated alumina coated with calcium chloride. In such a dual unit, one column can be used to dry the air while the other column can regenerate the desiccant.

Each tower is provided with a population valve 16 and 18, respectively.
By opening these valves, saturated air is introduced into the column through the inlet 20. The air that has entered the tower moves upwards, and as it passes through the desiccant packed in the tower, the moisture contained therein is removed by the desiccant.

The opening and closing of valves 16 and 18, and other valves in the system, are controlled by turning a cam timer provided in control box 22. In this cam type timer, when the cam rotates to reach and leave a specific position, a switch is opened and closed, and various valves in the device are opened and closed via solenoids. [m1 of the valve operated by the cam
The ll timing is shown in FIG. 2 and will be explained in detail later. Of course, the sequence operation of such a valve is Honkawa mi! In addition to mechanical means as described in , it is also possible to use electronic or pneumatic timing devices.

After the dried air is discharged from the upper part of the tower 12, it is passed through the pipe 2.
4 and through a check valve 26 to an outlet 28 . Similarly,
When column 14 is in a drying cycle, drying air exits υL through tube 30 at the top of 414 and passes through check valve 32 before reaching outlet 28.

A portion of the dry air reaching outlet 28 is diverted to line 34 by a purge control valve (not shown). The amount of dry air passing through tube 34 is monitored by meter 36 and the purge control valve is adjusted to divert the desired amount of dry air into tube 34. The dry air branched into tube 34 is passed through one of the etch regeneration valves 40 or 42 through a fitting 38 wide orifice.

Regeneration valves 40 and 42 are check valves that allow only flow from fitting 38 to pipes 44 and 46, respectively. Therefore, when the column 12 is used in a drying cycle and pressurized dry air is being supplied to the pipe 24, air pressure is applied to the pipe 44, the check valve 40 is biased to the closed state, and air is directed from the pipe 44 to the joint 38. flow is blocked. In this state, column 14 is in a regeneration cycle while column 12 is in a drying cycle. Therefore, no urging force is applied to the check valve 42 from the pipe 46 to open the valve, and the dry air from which the regeneration valve 42 is opened due to the pressure of the dry air in the pipe 34 and the joint 38 flows from the joint 38 to the pipe 46. flows to

Since the pressure on the left hand side of the valve 32 is greater than the pressure on the right hand side,
Drying air in tube 46 flows downwardly through column 14 through tube 30 to dry the desiccant in column 14. In winter, purge valves 48 and 50 are also provided, respectively. When these purge valves open, regeneration air is discharged through the blanked openings 52 and 54.

The gas drying device iot: is also provided with a repressurization valve 56. At the end of the regeneration cycle, when this repressurization valve 56 is opened, pressurized dry air is supplied via line 58 to fitting 38 and from fitting 39 to one side of the column. The pressurizing valve 56 sends pressurized air into the column prior to the start of the drying cycle so that the desiccant in the column is not disturbed even if pressurized and saturated air is pumped into the bottom of the column at the beginning of the drying cycle. It is for.

In the following explanation of the operation of the gas drying device 10, first the column 1
2 is in the drying cycle and column 14 is in the regeneration cycle. Figure 2 shows the opening and closing of the population valve and purge valve.
FIG. 6 is a diagram illustrating the operation sequence of various cam switches that perform lilJyjJ. In Figure 2, rl TCJ is inlet valve 1
6 and 18, the first timer cam switch is activated. In addition, [2TCJ is the second timer cam switch that operates the purge valve 48, and r3TCJ is the purge valve 50.
Hail the third timer cam that operates. Also, [4
The TCJ activates the fourth timer cam switch which activates the repressurization valve 56. In FIG. 2, the shaded area indicates the state in which the switch contact is closed, and the blank area indicates the state in which the switch contact is open.

A typical drying and regeneration cycle length is 10 minutes, so the 50% line shown in Figure 2 represents 5% of the total cycle.
Hail the minute has passed. That is, after 5 minutes have elapsed, the drying cycle and the regeneration cycle are switched, and the tower 12 that was performing the drying cycle switches to the regeneration cycle, and the tower 14 that was performing the regeneration cycle switches to the drying cycle.

While the column 12 is undergoing a drying cycle, the first timer cam switch rlTcJ opens the valve 16 and closes the valve 18, thereby allowing saturated air supplied into the system through the inlet 20 to pass through the valve. 16 to the bottom of column 12. Further, at the same time as the valve 16 is opened by the first timer cam switch, the barge valve 48 is closed by the third timer cam switch r3TCJ. All air passing through valve 16 is thus fed to the bottom of column 12. The pressure of the air supplied to the inlet 20 is approximately 1100 psi;
Its temperature is about 100°F. As the air flows upwardly through column 12, the desiccant in the column absorbs the moisture in the saturated air, resulting in 1q of dry air having a dew point of about -40 DEG F. in tube 24.

The pressurized dry air in tube 24 causes check valve 26 to open and acts on check valve 40 to open it. As the air passes through outlet 28, a portion of the dry air is branched into pipe 34 and passes through fitting 38, causing check valve 42 to open. This dry air then passes through pipe 46 to pipe 30 and is passed further down into column 14. In this regeneration cycle, the second timer cam switch r2TcJ is repeatedly opened and closed, and as a result, the barge valve 50 is intermittently, in other words, repeatedly opened and closed. In contrast, in conventional drying equipment, the purge valve 50 remains open during the regeneration cycle. Therefore, in this case, all the air branched into the tower undergoing the regeneration cycle is discharged to the atmosphere at a constant rate.

In the present invention, by repeatedly opening and closing the purge valve 50, the column 14 is repeatedly pressurized and depressurized, so that the dry air passing through the column 14 can absorb more moisture with a smaller purge flow rate. . Also, by opening and closing the barge valve 50, the flow of the discharged dry air is interrupted, thereby significantly reducing the amount of dry air required to regenerate the desiccant in the column. As a result, whereas in the conventional method, approximately 15% of the dry air formed in the drying tower was required for the regeneration cycle, the present invention requires approximately 15% of the dry air formed in the drying tower. Only about 6% is needed for this purpose.

As shown in FIG. 2, just before the eight towers are switched from the regeneration cycle to the drying cycle, a fourth timer cam switch activates valve 29, so that a portion of the drying air that would normally be pumped out outlet 28 is transferred to this regeneration cycle. from the cycle to the column about to be switched to the drying cycle. In this case, the purge piece cooperating with this column is incised, so that the column is pressurized. This pressurization occurs just before the inlet valve cooperating with the column is closed, so that the pressure inside the column is approximately equal to the pressure of the saturated air introduced from the bottom of the column. Therefore, even if the artificial valve is opened, the desiccant in the tower will not be disturbed by the sudden introduction of moisture-containing air.

Although the embodiments described above relate to a non-heating type two-unit gas drying apparatus, the present invention is equally applicable to a similar heating type gas drying apparatus.

Various embodiments are possible within the spirit and spirit of the invention.

[Brief explanation of the drawing]

FIG. 1 is a front view of a gas drying device according to the present invention, FIG. 2 is a timing chart showing the operation sequence of a cam switch that operates various valves in the device shown in FIG. 1, and FIG.
FIG. 3 is a plan view of the drawing device. 10... Gas drying device, 12.14... Drying tower, 1
6.18...Inlet valve, 20...Inlet, 22...Control box, 24.30,34,44.46°58...Pipe, 26.32...Check valve, 28. ...Outlet, 29...Valve, 36...Meter, 38...Joint, 40°42...Regeneration valve, 48.50...Purge valve, 52°54...Opening, 56 ...Repressurization valve.

Claims (7)

[Claims] (1) It has at least two towers containing a desiccant, into which air saturated with the moisture to be dried and dry air are alternately supplied, and the air saturated with moisture is dried by the desiccant. A gas drying device that regenerates a desiccant that has become moist due to absorption of water contained in saturated air with dry air. an inlet valve for introducing the saturated air into the tower and sending the introduced saturated air through a desiccant to obtain dry air from the tower outlet; and alternately opening and closing the inlet valve to dry the moisture-saturated air. An inlet valve control means is provided in each column to supply saturated air to only one column during the drying cycle, and an inlet valve control means is provided in each column to introduce dry air into the column and to pass the introduced dry air into the desiccant absorbing moisture. a regeneration valve for removing water from the desiccant and regenerating the desiccant by drying air sent through; the regeneration valve is alternately opened and closed to regenerate the desiccant; only one column is allowed to dry during the regeneration cycle; regeneration valve control means for supplying air;
a purge valve provided in each tower to discharge the air used for regeneration of the desiccant from the tower in which the regeneration cycle was performed; during the regeneration cycle, the purge valve is alternately opened and closed to regenerate the desiccant; A gas drying apparatus comprising purge valve control means for alternately pressurizing and depressurizing the column during the regeneration cycle and limiting the amount of air discharged through the purge valve. (2) further comprising valve means for branching a portion of the dry air obtained from the first column during the drying cycle and supplying the branched dry air portion to the second column performing the regeneration cycle; The gas drying apparatus according to claim 1, characterized in that: (3) Further, at the end of the drying cycle, a portion of the pressurized dry air obtained from the first column is branched and the branched pressurized dry air portion is transferred to the second column which is about to finish the regeneration cycle. 2. The gas drying system of claim 1, further comprising a repressurization valve for closing a purge valve cooperating with the second column and pressurizing the second column prior to the start of the drying cycle. Device. (4) It has at least two towers containing a desiccant, into which air saturated with moisture to be dried and dry air are alternately supplied, and the air saturated with moisture is dried by the desiccant. A gas drying device that regenerates a desiccant that has become moist due to absorption of moisture contained in saturated air with dry air. an inlet valve for introducing the saturated air into the tower and sending the introduced saturated air through a desiccant to obtain dry air from the tower outlet; and alternately opening and closing the inlet valve to dry the moisture-saturated air. an inlet valve control means for supplying saturated air to only one column during the drying cycle; branching off a portion of the dry air obtained from the first column during the drying cycle and performing a regeneration cycle on a portion of the dry air; valve means for supplying dry air to a second column; provided in each column for introducing dry air into the column and sending the introduced dry air through a desiccant absorbing moisture; drying with the dry air; a regeneration valve for removing moisture from the desiccant and regenerating the desiccant; a regeneration valve control that alternately opens and closes the regeneration valve to supply dry air to only one column during the regeneration cycle for regenerating the desiccant; Means; a purge valve provided in each column for discharging the air used for regenerating the desiccant from the column in which the regeneration cycle was performed; A gas drying apparatus characterized in that it comprises purge valve control means for alternately pressurizing and depressurizing the column in which regeneration takes place during the regeneration cycle and for limiting the amount of air discharged through the purge valve. (5) It has at least two towers containing a desiccant, into which air saturated with moisture to be dried and dry air are alternately supplied corresponding to the drying stage and the regeneration stage, respectively. In the step, the air saturated with moisture is dried with a desiccant agent, and in the regeneration step, the air is regenerated by the air that has passed through the desiccant, which has become moist due to absorption of moisture contained in the saturated air. A method for drying gas using: introducing saturated air into a tower in the drying stage, passing the introduced saturated air through a desiccant and obtaining dry air from the tower outlet; A part of the dry air obtained from the tower is introduced into another tower in the regeneration stage, and the dried air is passed through the desiccant, which is moist due to absorption of water in the drying stage, and the water in the desiccant is removed. The desiccant is regenerated by absorbing it with dry air, and the other columns in the regeneration stage are alternately pressurized and depressurized to periodically expand the air in the other columns, and the desiccant is removed from the desiccant. A drying method comprising the step of absorbing more moisture into the dry air. (6) The gas drying device has a purge valve for discharging air used in the regeneration stage, and the pressurization and depressurization stages alternately operate the purge valve for discharging air from the other column. 6. A method according to claim 5, characterized in that it is carried out by opening and closing, thereby reducing the amount of air discharged from said other columns. 7. A method according to claim 6, characterized in that the dry air introduced into said other columns is less than 10% of the total amount of dry air obtained from said first column.