JPS62235201A - Method and device for concentrating oxygen in high yield-high concentration - Google Patents

Abstract

PURPOSE:To improve the yield of highly concentrated O2 by using a pressure swing system applying the adsorptivity of molecular sieves to remove Ar in O2 separated from air. CONSTITUTION:The air compressed by a compressor 1 is dehumidified by a device 2, and sent to an ordinary-temp. adsorption tower 4 through a pressure accumulator 3. The air is again dehumidified in the tower 4, CO2 and a part of N2 are simultaneously removed, and the air is sent to a low-concn. O2 pressure accumulator 5. The gas leaving the accumulator is cooled by a heat exchanger 7 and a cooler 8, and sent to a low-temp. adsorption tower 10. Since gaseous Ar is initially separated from the tower top, a valve V6 is opened, and the Ar is discharged to the atmosphere through a pressure accumulator 11. When O2 tends to separate thereafter, the valve V6 is closed, a valve V7 is opened, and the separated O2 is collected as a product through a high-concn. O2 pressure accumulator 12. Before N2 then tends to separate, the valve V7 is closed, a valve V8 is opened, and an E tower to be subsequently used is flushed with high-concn. O2. The valve V8 is then closed, a valve V9 is opened, and the desorbed gas is sent to a low-concn. O2 bypass tank 13. The low-concn. O2 increases the O2 concn. in the raw air, and enhances the yield of the product O2.

Description

DETAILED DESCRIPTION OF THE INVENTION 3-1 Purpose As is well known, molecular sheep have the property of selectively adsorbing a specific gas at room temperature. A method of concentrating and separating oxygen in the air by applying this property is also known. However, in this known method, the oxygen concentration is said to be limited to 95%. The reason is said to be that it is difficult to separate and remove argon gas. The purpose of the present invention is to remove this argon gas to reduce the oxygen concentration to 99% or more, and to increase the yield by applying the low temperature adsorption ability of molecular sheep.

3-2 Argon Gas Removal Method The adsorbent used in the known oxygen concentrator is Molecular Sheeps 5A. This Molecule Sheeps
It is also known that 5A does not separate argon gas and oxygen at room temperature, but when used at low temperatures (-40 to -70°C), argon gas and oxygen are separated and the nitrogen adsorption performance is extremely improved. It is as follows.

By applying this property, it becomes possible to concentrate oxygen at a high concentration and with a high yield.

3-3 Separation experiment of argon gas and oxygen using Molecular Sheeps 5A Figure 1 is a diagram of room temperature analysis of air using a gas chromatograph.

Analysis conditions Column size 3m/x3m Column packing material Molecular Sheeps 5A Column temperature 30°C Carrier gas Helium carrier gas flow rate 40-/Sensitivity voltage sensitivity 1024MV Chart speed 10u/Steel Names listed in Figure 1 ■Oxygen and Precipitation of argon gas ■ Precipitation of nitrogen Principle of oxygen concentration at room temperature Oxygen precipitation time T1 in Figure 1 is the time for collecting the oxygen product from the concentrator and is approximately 40 seconds Nitrogen precipitation time T of scalpel 1
2 corresponds to the desorption time of the concentrator, which is about 1 minute and 40 seconds.

As can be seen, the desorption time requires nearly 25 times the adsorption time. For this reason, in the case of oxygen concentration, the number of adsorption towers is four and they are used alternately. Recently, in order to speed up the time of nitrogen desorption, three towers have been created by washing the product with oxygen during desorption.

FIG. 2 is a diagram of low-temperature analysis of air using a gas chromatograph.

Analysis conditions Column size 3) x 3 m Column packing material
Molecular Sheeps 5A Column temperature -45℃ Carrier gas Helium Carrier gas flow rate 40 d/m Chart speed 10H/4 Names shown in Figure 2 ■ Argon gas precipitation ■ Oxygen precipitation ■ Nitrogen precipitation At low temperature Principle of oxygen concentration The argon gas precipitation time T3 in Figure 2 corresponds to the release time of argon gas from the concentrator, which is about 40 seconds, and the oxygen deposition time T4 in Figure 2 corresponds to the oxygen collection time from the concentrator. The nitrogen precipitation time T5 in FIG. 2, which is about 1 minute and 40 seconds, corresponds to the nitrogen desorption time of the concentrator, which is about 3 minutes and 20 seconds. The time for releasing argon gas and collecting time for oxygen is about 2 minutes and 20 seconds.The desorption time for nitrogen is about 15 times longer than this, so it can be seen that oxygen can be collected by alternately using three adsorption towers. .

3-3-8 Figure 3 shows the oxygen concentration measured by gas chromatography.
This is a low-temperature analysis of a gas containing about 2.5 g of argon gas in addition to about 50 g of nitrogen.

Analysis conditions Column size 3ag/X3m Column packing material Molecular Sheeps 5A Column temperature -45℃ Carrier gas Helium carrier gas flow rate 40 m/W Voltage sensitivity 1024MV Chart speed 10m/'' Names shown in Figure 3 ■Argon Gas precipitation ■ Oxygen precipitation ■ Nitrogen precipitation Oxygen concentration 50%, nitrogen concentration 50%, argon gas 2.5
% of oxygen concentration at low temperature The argon gas precipitation time T6 in Figure 3 corresponds to the argon gas release time of the concentrator, which is about 40 seconds, and the oxygen deposition time T7 in Figure 3 corresponds to the argon gas release time of the concentrator. This corresponds to the collection time of oxygen, which is about 1 minute and 40 seconds, and the nitrogen precipitation time T8 in FIG. 3 corresponds to the desorption time of the concentrator, which is about 1 minute and 40 seconds. As can be seen from this, the desorption time and the adsorption time are the same, so it can be understood that the adsorption tower can be used by switching between two towers alternately. Father, if the product oxygen is used to wash the adsorption tower during desorption, as in a room-temperature concentrator, the yield can be improved.

3-4 Description of the present invention FIG. 4 is a flow sheet of the oxygen concentrator of the present invention.

8-4-1 Explanation of names of each equipment ■ Feed air compressor ■ Dehumidification device ■ Feed air pressure accumulator ■ Room temperature adsorption tower AXBXC ■ Low concentration oxygen pressure accumulator ■ Vacuum pump ■ Heat exchanger ■ Cooler ■ Cooling device [phase ] Low-temperature adsorption tower D, E ■Argon gas pressure accumulator ■High concentration oxygen pressure accumulator @ low concentration oxygen bypass tank [Phase] Oxygen concentration meter ■1 to V9 Switching valve F1 to F2 Throttle plate P Pressure transmitter M Motor CV Argon gas Flow rate adjustment valve 3-4-2 Explanation of the concentration method of the oxygen concentrator in Figure 4 Air compressed to 3 to 5 #/- by the raw air compressor is passed through the dehumidifier to a dew point of O to -10°C, and the raw air pressure is accumulated. The water from the room-temperature adsorption tower is dehumidified again to a dew point of -50 to -60°C, and some of the carbon dioxide and nitrogen are removed before being sent to a low-concentration oxygen pressure accumulator. After the precipitation of oxygen is completed and before the precipitation of nitrogen, the valve (1) is closed and the valve (V2) is opened to flush low-concentration oxygen to the B tower to be used next. When the cleaning of the B tower is completed, close the V2 valve and v3
Open the valve and close the V3 valve when the pressure inside the tower becomes close to atmospheric pressure■
Open the valve and vacuum clean the inside of the tower using a vacuum pump. When vacuum cleaning is completed, close the V4 valve. In this way, the three towers are alternately used to continuously produce low concentration oxygen.

Next, the gas coming out of the low concentration oxygen pressure accumulator is passed through a heat exchanger to O~-
The mixture is cooled to 10°C, further cooled to -40 to -70°C in a cooler, and sent to a low-temperature adsorption tower. Since argon gas is first deposited from the top of the low-temperature adsorption tower, this argon gas is
Open valve 6 and release the argon gas to the atmosphere through the pressure accumulator. When the argon gas has been released and oxygen is about to precipitate, the v6 valve is closed and the v7 valve is opened and the precipitated oxygen is collected as a product through a high concentration oxygen pressure accumulator.

After the precipitation of oxygen is completed and before nitrogen is about to be precipitated, close the valve (1) and open the valve (V8) to flush highly concentrated oxygen to the E tower to be used next. When the cleaning of the E tower is finished, close the v8 valve and
Open valve 9 and send the desorption gas to the low concentration oxygen bypass tank. Since this bypassed low-concentration oxygen has a higher oxygen concentration than air, it increases the oxygen concentration of the raw material air and increases the yield of product oxygen.

In this way, high concentration oxygen can be produced continuously.

3-5 Operation method of high concentration oxygen concentrator of the present invention 3-5-1 Operation method of low concentration oxygen concentrator be inversely proportional. Applying this property, it is possible to arbitrarily adjust the switching time of the switching valve to keep the oxygen concentration constant.

The output voltage of the oxygen concentration meter in front of the low-concentration oxygen pressure accumulator shown in FIG. 4 is connected to the inverter so that when the oxygen concentration decreases, the inverter frequency increases, and when the oxygen concentration increases, the inverter frequency decreases.

This inverter rotates a synchronous motor,
A proximity switch is set on the notched disc attached to the synchronous motor to switch each valve.

FIG. 5 is a diagram of the process, and FIG. 6 is a diagram of pulp switching time.

Names listed in Figure 5 ■ Raw air compressor ■ Low concentration oxygen concentrator ■ High concentration oxygen concentrator ■ Oxygen concentration meter ■ Inverter ■ Synchronous motor ■ Notch disk ■ Proximity switch ■ Sequencer [phase] ■ 1 to v4 each switching Names listed in valve diagram 6 V1 Raw air inlet valve opening time ■ Low concentration oxygen collection time V2 Cleaning valve opening time ■ 3 Atmospheric release valve opening time ■ 4 Vacuum cleaning valve opening time 3-5-2 High How to operate the concentration concentrator The concentration of concentrated oxygen leaving the low-humidity adsorption tower changes in inverse proportion to the change in the amount of concentrated oxygen used. By adjusting the switching time of the switching valve using this property, the concentration of high concentration oxygen can be kept constant regardless of the amount of high concentration oxygen used.

The output voltage of the oxygen concentration meter in front of the high-concentration oxygen pressure accumulator shown in FIG. 4 is input to the input of the inverter, and as the oxygen concentration increases, the inverter frequency decreases, and as the oxygen concentration decreases, the inverter frequency increases. This inverter rotates a synchronous motor, and a switching disc attached to the synchronous motor operates a proximity switch to switch each valve. FIG. 7 shows the process, and FIG. 8 shows the valve switching time.

Names listed in Figure 7 ■ Raw air compressor ■ Low concentration oxygen concentrator ■ High concentration oxygen concentrator ■ Oxygen concentration meter ■ Inverter ■ Synchronous motor ■ Notched disc ■ Proximity switch ■ Sequencer [phase] ■ 5 to V9 switching valve diagram Names listed in 8 v5 Raw material gas introduction valve opening time V6 Argon gas release valve opening time v7 High concentration oxygen collection valve opening time v8 Cleaning valve opening time V9 Low concentration oxygen recycling valve opening time 3-5-3
How to adjust the amount of argon gas released from a high concentration concentrator The amount of argon gas released needs to be proportional to the amount of high concentration oxygen used, so there are aperture plates on the high concentration oxygen outlet side and the argon gas release side. A sequencer compares and detects the front and back of the diaphragm plate and makes the amount of argon gas released proportional to the amount of high concentration oxygen used.

Figure 9 shows this process.

Names listed in Figure 9 ■ Raw material air compressor ■ Room temperature concentrator ■ Low temperature concentrator ■ Argon gas release side throttle plate ■ High concentration oxygen side throttle plate ■ Argon gas side differential pressure converter ■ Oxygen side differential pressure converter ■ Sequencer Cv Argon gas flow rate adjustment valve 3-5-4 How to adjust the amount of raw air according to the amount of high-concentration oxygen used When the amount of high-concentration oxygen used decreases, the pressure of the high-concentration oxygen accumulator increases and the oxygen concentration increases. This increases the switching time. Then, the pressure of F: F: group pressure≠;
μ field 1 - When the accumulator pressure of this low concentration of oxygen is converted into voltage using a pressure converter and input to the input of the inverter, the frequency of the inverter drops.

Then, the rotational speed of the motor of the raw air compressor decreases, and the amount of compressed raw air is reduced.

Conversely, as the amount of highly concentrated oxygen used increases, the amount of compression of the raw material air increases. By doing so, it is possible to save power by adjusting the amount of compression of the raw material air depending on the amount of high concentration oxygen used.

Names listed in Figure 10 ■Raw material air compressor ■Normal temperature oxygen concentrator ■Low temperature oxygen concentrator ■Low crystalline oxygen pressure accumulator ■Pressure voltage converter ■Inverter ■Electric motor for raw material air compressor that's all

Claims (2)

[Claims] (1) A method for concentrating oxygen in the air at high concentration and yield using a pressure swing method that utilizes the low-temperature adsorption properties of Molecular Sheeps. (2) A device that condenses oxygen in the air at high concentration and yield using a pressure swing method that utilizes the low-temperature adsorption properties of Molecular Sheeps.