JPS61187916A - Controlling method of on-off valve in oxygen condensing apparatus - Google Patents

Abstract

PURPOSE:To obtain quickly the gaseous product having the prescribed concn. when the titled apparatus is started up by pressurizing the inside of an adsorption tower in the atmosphere and above in a period of the stoppage, making the other adsorption tower decided preliminarily a state wherein the regeneration is finished and stopping the apparatus. CONSTITUTION:When the adsorption of N2 and H2O is certainly started in the first adsorption tower 5 and a cycle is continuously repeated and thereafter an apparatus is stopped, an on-off valve 17 of a product takeout port is closed but the operation is continued till one cycle is finished and in a point of time when it is finished, the stopping operation wherein the regeneration of the first adsorption tower and the pressurizing of both towers are performed is started. The first adsorption tower is pressurized in the atmosphere and above by closing the on-off valve for the discharge by the time-lag wherein the time is preliminarily set faster than the closure and stoppage time of all the on-off valves and an air compressor. In a period of the restarting up, the on-off valves are controlled so as to adsorb N2 and H2O certainly in the first adsorption tower.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oxygen concentrating method that enables a product oxygen-enriched gas of a desired concentration to be obtained in a short time at the start of operation of an oxygen concentrator.

The purpose of this application is to pressurize the inside of the adsorption tower with atmospheric air or pressure air at the time of shutdown so that oxygen-enriched gas at a predetermined concentration can be obtained quickly when the adsorption tower is restarted from the time of shutdown, and one of the An object of the present invention is to provide an oxygen concentrating method characterized in that the determined adsorption tower is brought to a state where regeneration has been completed and the apparatus is stopped.

Another object of the present application is to prevent nitrogen and moisture once adsorbed at the time of stoppage from flowing into the adsorption tower that has finished regeneration, and to prevent the oxygen-enriched gas stored in the buffer tank from flowing into the adsorption tower at the time of stoppage. An object of the present invention is to provide an oxygen concentrating method characterized in that it cannot be used for regeneration of oxygen.

The object of the present invention is to provide an oxygen concentrating method that allows the adsorption of nitrogen and moisture to be started from the adsorption tower that has been regenerated when the adsorption tower is restarted from a stopped state.

To explain an embodiment for achieving the above purpose, a first N absorption tower (5) and a second adsorption tower (5) are supplied to an air compressor (1) through respective on-off valves (3) and (3). The ends of the two are connected in parallel with each other using piping (2).

At the other ends of the first absorption tower (5) and the second adsorption tower (5), a check valve uI and a regeneration opening/closing yP<S> and (8) are connected in parallel to the conduit (6) (d> and Conduit (connected by force (i).

The regeneration on-off valves (8) and (8) are connected to the outlet side of the precision flow control valve ([3] with a conduit qυαυ.

Check valve (10 and αQ are introduced t (121ab and check valve I
The inlet side of the precision flow control valve a4 is connected to the first part (9) of the conduit α3H.

A buffer tank US, a product outlet opening/closing valve Uη, a pressure reducing valve u1, a flow rate adjustment valve Sumyu, and a flow meter (to) are connected in series to the check valve α4 through a conduit (to). &D
Is it an exit conduit? It shows.

Since the present application is structured like the above-mentioned flow sheet, its operation will be explained with reference to FIGS. 1 and 2. In FIG. Figure 2 shows the state in which the g22 absorption tower (5) is being regenerated. In Figure 2, the oxygen-enriched gas is sent from the second absorption tower (5) to the buffer tank uI to regenerate the first absorption tower (5). This indicates a state in which the raw air gas 1f
! : Adsorption tower (5) that adsorbs nitrogen and moisture by compressing it with an air compressor (1) and passing it through a supply on-off valve (3) from a conduit (2)
send to The adsorption tower (5) is filled with a zeolite-based crushed nitrogen adsorbent and an alumina-based moisture adsorbent, in which the scum and moisture tI & gas that is not adsorbed after being layered, i.e., oxygen-enriched gas. through the conduit (6) to the check valve Ql
pass through. This is called the adsorption process. This oxygen-enriched gas passes through the check valve (14) on one side, passes through the conduit u9, the buffer tank ae1 product outlet opening/closing valve αη, the flow 1f control valve, and the flow meter (a), and then passes through the conduit (2υ) as product gas. On the other hand, oxygen-enriched gas passes from conduit QS5 through precision flow control valve Q3, conduit aO1 regeneration valve (open/closed), and south conduit, where nitrogen and moisture adsorption had previously become a saturated trap. It is sent to the second adsorption tower (g), and the first adsorption tower (5)
During the time until the adsorption of nitrogen and moisture reaches saturation, the second absorption tower (5) is cleaned with oxygen-enriched gas and the discharge on/off valve (4) is used to adsorb nitrogen and moisture again. It is then released into the atmosphere along with the nitrogen and moisture that it had adsorbed.

This is called the regeneration process.

In this application, this adsorption process and regeneration process are explained using the time chart shown in Fig. 3.
+41+81 (8) An oxygen concentrator with a capacity of 5KL capable of carrying out the pressure swing method in which the gas flow is alternately switched and operated as shown in FIGS. 1 and 2 of the flow sheet, the device This invention is characterized by the switching time of the on-off valve, and operates as follows in order to quickly obtain oxygen-enriched gas at a predetermined concentration when restarting from a stopped state.

a. Pressurize the inside of the adsorption tower to above atmospheric pressure when stopping.

b. One of the predetermined adsorption towers is brought to a state where regeneration has been completed, and the apparatus is stopped.

To prevent the nitrogen and moisture once adsorbed during CO stoppage from flowing into the adsorption tower that has finished regeneration, and to prevent the product oxygen-enriched gas stored in the buffer tank at the time of stoppage from being used for regeneration of the adsorption tower. .

d. When restarting from a stopped state, adsorption of nitrogen and moisture should always be started from the adsorption tower that has finished regeneration.

The 80-piece device does not require any particularly detailed work and can be constructed using only various types of commercially available squares.

In addition, especially in the case of sludge Otts and quantity control valves, the flow direction is always the same, so even if a precision needle valve or the like, which has different flow rates in the forward and reverse directions, is used, the flow rate remains constant. Moreover, it is easy to adjust.

f, 1 [A major feature is that it is easy to adjust when switching between 50 Hz and 60 Hz.

The operation of the present invention for obtaining the above characteristics will be explained based on the time chart shown in FIG. 3. In the pulse type diagram, the upper side is ON and the lower side is OFF, showing a state in which the pulse type is alternately opened and closed in 30 second units. The operations shown in Figures 1 and 2 are performed once each when the valve (3), the discharge on-off valve (4), the regeneration on-off valve (d), the product outlet on-off valve, and the supply on/off valve are opened. valve (3), discharge on-off valve (4), and regeneration on-off valve (8)
) is closed. After 30 seconds, close the supply on-off valve (3), discharge on-off valve (4), and regeneration on-off valve (d), and close the supply on-off valve (d), discharge on-off valve (4), and regeneration on-off valve (8). open. The opening/closing operation described above is repeated as one cycle.

Intervention #? : When operating, adsorption of nitrogen and moisture is always started from the first adsorption tower (5), and this cycle is continuously repeated. Next, when stopping the apparatus, assume that the apparatus is switched '&OFF Ic L at an arbitrary time point (a) in an arbitrary section (4) in one cycle.

At this moment, the pond that closes the product outlet opening/closing valve surface of the product oxygen-enriched gas continues to operate until the end of one cycle including section capture. A stop operation (①) including a time lag (b) in the discharge on-off valve (4), which is an operation to pressurize the tower, is started. The stop operation (2), which is the same as the normal operation cycle except for the product outlet opening/closing valve (17) and the discharge opening/closing valve (4), must always continue operation until the gas flow is as shown in Figure 2. The regeneration operation of the adsorption tower (5) is ended. In addition, the discharge on-off valve (4) is opened for a preset time lag (b) from the closing and stopping time of all the on-off valves and the air compressor.
By closing the first AF tower (5) early, it is possible to pressurize the first AF tower (5) to a pressure higher than atmospheric pressure, which is a preset state.

When starting up the operation again, the on-off valve must be controlled to adsorb nitrogen and moisture from the AT adsorption tower (5), and the oxygen-enriched gas stored in the buffer tank i1e created during the previous operation must be Since it can be used directly as a product, high-purity oxygen-enriched gas can be obtained as soon as the device is operated.

Experimental Example 5 Inner volume filled with crushed Affl zeolite: 2.4
Using two 31 adsorption towers, adsorption regeneration was performed mutually with 30 seconds switching at a maximum air pressure of 21194G, and 0.295% ll was obtained.
The following experiment was attempted using an experimental device regulated by a precision flow control valve (IJ) so that the flow would flow at 50°C.

Experimental example [l] As an operation when stopping the equipment, all on-off valves were closed the moment the operation switch was turned OFF without taking the above-mentioned precautions, and the air compressor (1) was stopped. FIG. 7 shows the results of measuring the minimum oxygen concentration and the time taken to return to Qt95'X when the FE setting was restarted after a certain period of time after the stop operation shown in the figure was performed.

Experimental Example [1] The results of measuring the minimum oxygen concentration and the time required for the oxygen concentration to return to 95% when the device #t is restarted after a certain period of time after performing the stop operation shown in Fig. 4 according to the present invention are as follows. It is shown in FIG.

As shown in the results in Figures 6 and 7, the present invention makes it possible to significantly shorten the startup time from restart to 95% oxygen concentration from 60 minutes to 18 minutes, and furthermore, the minimum oxygen concentration is 95%. It was found that it did not go below %.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams showing the flow of each gas at 70- of the present device and during continuous operation. FIG. 3 is a flow sheet diagram in which the adsorption tower and buffer tank of FIGS. 1 and 2 are integrated. Fig. 4 is a time chart of the control method of the on-off valve during equipment operation and the method of controlling the on-off valve when the equipment is stopped according to the present invention, and Fig. 5 is a time chart of the control method of the on-off valve when the equipment is stopped in general. , FIG. 6 is a diagram showing the oxygen concentration and rise time of the oxygen-enriched gas in the present invention, and FIG. 7 is a diagram showing the oxygen concentration and rise time at the start of operation of a general apparatus.

Claims (2)

[Claims] (1) In a two-column type device that uses an adsorbent to condense oxygen from air using the pressure swing method, operation start and stop operations are performed to bring the oxygen concentration of the product oxygen-enriched gas to the specified concentration extremely quickly. Among the operation controls that include, be sure to apply a pressure higher than the pre-specified atmospheric pressure to both adsorption towers.
Moreover, one of the adsorption towers is stopped after the regeneration process is completed, and when the adsorption tower is restarted, the adsorption process is always started from the adsorption tower that has completed the regeneration. (2) The raw air gas compressed by the air compressor is sent to the first adsorption tower via the supply on-off valve, and nitrogen and moisture are adsorbed, and the oxygen-enriched gas is passed through the check valve to the product oxygen-enriched gas outlet. The oxygen-enriched gas is sent to the second adsorption tower installed in parallel with the first adsorption tower via a buffer tank having an on-off valve and a regeneration on-off valve, and the oxygen-enriched gas is stored in the buffer tank and the second
At any point in the oxygen concentration process in which the first adsorption tower and the second adsorption tower are used to alternately act in a fixed cycle to release the nitrogen and moisture adsorbed in the adsorption tower into the atmosphere through the release on/off valve. When the switch of the device is turned off, the specified operation of the on-off valve is continued until the end of the next cycle after the cycle in which it was turned off, and only the release on-off valve that is performing the release action is closed earlier than the end time of the other on-off valves. A method for controlling an on-off valve in an oxygen concentrator, characterized by: