JPH0640940B2 - Regeneration device for adsorber in air separation device - Google Patents

Description

Description: Industrial field of use The present invention removes water and the like from compressed air and cools it in a stage before a main heat exchanger that supplies a cooling raw material gas to a rectification tower of an air separation device. Improvement of the regenerator of the adsorber consisting of a heat regenerative structure for obtaining the raw material gas air, and air separation that reduces the thermal shock generated in the regenerator heat exchanger of the adsorber and prevents the occurrence of thermal fatigue fracture The present invention relates to a regenerator for an adsorber in an apparatus.

BACKGROUND ART An air separation apparatus pressurizes and cools air from which water, carbon dioxide, etc. have been removed to form a raw material gas, and separates and purifies it in a rectification tower by utilizing the difference in boiling points of each gas.

In the previous stage of the main heat exchanger that supplies the cooling raw material gas to the rectification tower of this air separation device, an adsorber that adsorbs and separates moisture and carbon dioxide gas by utilizing the temperature change amount of the cooling and heating of the adsorbent. Is used.

The adsorber consists of an adsorption tower filled with a pair of adsorbents, and in order to improve adsorption efficiency, after cooling, adsorption near room temperature and desorption by heating are alternately performed. The low-temperature waste gas from the reactor is used, and the heated waste gas is used for heating by the heat exchanger for regeneration and the heater in the subsequent stage.

The structure of such an adsorber regenerator will be described in detail with reference to FIG. 4 showing a circuit of a conventional device.

Is introduced through the suction filter (1), compressed air containing compressed water by the compressor (2) is a catalyst or the like at purifier (3), is removed SO _X, NO _X.

Furthermore, the compressed air that has become hot due to compression is
The heat exchanger for regeneration (0) (4) and the aftercooler (5) are cooled to near room temperature, for example, the adsorber (10) in the adsorption process,
Supplied via the solenoid valve (11) to the adsorption tower (10a), the adsorber (10a)
After H ₂ O and CO ₂ are removed inside, it is supplied as raw material air to the main heat exchanger (not shown) of the air separation device through the check valve (13) and the filter (15).

On the other hand, after passing through the main heat exchanger, N
_The remaining waste gas from which ₂ , _2, etc. have been separated recovers cold heat by another heat exchange device (not shown), then returns again as a gas at about room temperature, and flows in the following two ways.

One is provided with a flow path for regenerating the adsorbent in one of the adsorption towers of the adsorber (10), and during the heating step, the three ways provided in the return waste gas passage (6) are provided. It is switched by the switching valve (7), flows into the regeneration heat exchanger (4), and is preheated by high-temperature compressed air in the heat exchanger (4), and then is heated by the heater (8) to, for example, about 200 ° C. Heated and supplied to the adsorber (10b) during the regeneration process through the check valve (16), after desorbing H ₂ O and CO ₂ from the adsorbent, then through the solenoid valve (18) from the exhaust tower (20) Emitted into the atmosphere.

Next, during the cooling process in which the adsorber (10b) after heating and regeneration is cooled in preparation for the next adsorption process, the waste gas passes through the three-way switching valve (7) and is bypassed to the adsorber (10). Flow to (9), check valve
After being supplied to the adsorption tower (10b) through the (16) to cool the adsorbent, the adsorbent is discharged from the electromagnetic valve (18) through the exhaust tower (20).

For example, it is performed at the following process times.

That is, the pair of adsorbers (10a) (10b) are used by alternately switching them in a predetermined time cycle. Problems with the prior art As described above, during the cooling process of the adsorption tower (10b), the heat exchange for regeneration is performed. Waste gas does not flow into the vessel (4), and the temperature of the compressed air introduced into the regeneration heat exchanger (4) itself is, for example, about 110 ° C.

However, when the adsorber (10) is switched and the adsorption tower (10a) is in the heating step, the three-way electromagnetic switching valve (7) is switched, and a sudden cold waste gas, for example, a large amount of waste gas of about 10 ° C is discharged. It flows into the regeneration heat exchanger (4) and the temperature near the waste gas inflow part of the regeneration heat exchanger (4) drops sharply from 110 ° C to 60 ° C (temperature change of 50 ° C), which is a kind of heat shock. give.

This thermal stress is given to the heat exchanger for regeneration (4) every time the adsorber (10) is switched, and therefore, due to long-term use,
There was a risk of fatigue failure of the heat exchanger.

An object of the present invention is to improve the durability of a regenerator for an adsorber having a heat regenerative structure, and to reduce the thermal shock generated in the heat exchanger for regeneration of the adsorber to prevent thermal fatigue damage. Intended for equipment.

Structure and effect of the invention The present invention has a pair of adsorption towers arranged in parallel, and it is possible to alternately introduce the low-temperature waste gas from the main heat exchanger and the waste gas heated in the regeneration heat exchanger. In the heat regeneration type adsorber, the waste gas from the main heat exchanger can be introduced into the regeneration heat exchanger upstream of the three-way switching valve that switches the adsorption gas or regeneration heat exchanger. A branch pipe is provided, an on-off valve is provided in the branch pipe, and the pipe connecting the regeneration heat exchanger and the heater is branched to connect the pipe connecting the exhaust side of the adsorber and the exhaust tower. For an adsorber in an air separation device, which is connected in the middle and is provided with an on-off valve in this branch line to introduce a small amount of waste gas to precool the regeneration heat exchanger before switching the heating. It is a regenerator and also uses waste gas from the main heat exchanger as an adsorber or heat for regeneration. A small amount to the regeneration heat exchanger, upstream of the 3-way switching valve for switching to the exchanger, or upstream of each on-off valve provided in the bypass pipe line to the adsorber or in the waste gas passage to the regeneration heat exchanger Is a regenerator for an adsorber in an air separation device, which is provided with a branch pipe through which the waste gas can be introduced to constantly precool the regenerator heat exchanger. The three-way switching valve that switches the waste gas to the adsorber or the heat exchanger for regeneration is a continuous switching valve, and when switching to the heat exchanger for regeneration, the introduction amount is continuously increased from a small amount,
It is an adsorber regenerator in an air separation device characterized by precooling a regenerator heat exchanger.

According to the present invention, in the above-described three-way switching valve in the waste gas passage, a large amount of low-temperature waste gas having a large temperature change amount with the regeneration heat exchanger is rapidly introduced after switching, and the waste gas inflows into the regeneration heat exchanger. The thermal shock near the section can be reduced by introducing a small amount of waste gas before switching or at all times to precool the regeneration heat exchanger or reduce the temperature change during valve switching, or by using a continuous switching valve. By increasing the amount introduced from a small amount continuously and over time, the thermal shock can be greatly reduced and the life of the heat exchanger for regeneration can be extended.

Disclosure based on the drawings of the invention FIG. 1 is a circuit diagram of a reproducing apparatus according to the present invention.
2 and 3 are circuit explanatory diagrams showing another embodiment of the present invention.

Example 1 First, the regenerator shown in FIG. 1 has the same configuration as that of FIG. 4 described above, and further branches from the upstream side of the three-way electromagnetic switching valve (7) in the waste gas passage (6). A branch pipe (41) connecting to the branch pipe (40) connecting the switching valve (7) and the regeneration heat exchanger (4) is provided, and the solenoid valve (30) is arranged therein.

Also, the branch pipe (42) branched from the pipe connecting the regeneration heat exchanger (4) and the heater (8) is connected to the exhaust side solenoid valves (18) (19) of the adsorber (10) and the exhaust gas. A solenoid valve (31) is provided in the branch pipe connected to the middle of the pipe connecting the tower (20).

Action / Effect The action / effect of the regenerator having the branch pipes (41) (42) and the solenoid valves (30) (31) will be described below. , For example, open the solenoid valve (30) and solenoid valve (31) a few minutes before switching the valve, and
An amount 1/10 of the normal flow rate of (6) is supplied to the heat exchanger (4) for regeneration.

The temperature in the vicinity of the waste gas inflow part of the regeneration heat exchanger (4) is the temperature of the compressed air introduced, for example, about 110 ° C, and a predetermined amount before the switching to the heating step in the regeneration step. By inflowing the waste gas of, the temperature once drops from 110 ℃ to 85 ℃ (temperature change 25 ℃) and is pre-cooled.

After that, the three-way electromagnetic switching valve (7) is switched, the electromagnetic valve (30) and the electromagnetic valve (31) are closed, and the entire flow rate of the waste gas is supplied to the regeneration heat exchanger (4). The temperature near the waste gas inflow section drops from about 85 ° C to 60 ° C (temperature change amount 25 ° C), the temperature change amount becomes small, and the thermal shock can be significantly reduced.

A part of the waste gas used to precool the regeneration heat exchanger (4) is mixed with the desorption gas and discharged to the exhaust tower (20).

The waste gas, which has passed through the regeneration heat exchanger and whose temperature has risen, is mixed with the waste gas from the bypass pipe (9), and the adsorber (10 ), In which case the solenoid valve (31) and the solenoid valve (31)
Needless to say, a pipe line connecting the outlet of the adsorber (10) is unnecessary.

Embodiment 2 Next, the regenerator shown in FIG. 2 has the same structure as that of the regenerator shown in FIGS.
A small amount of waste gas branched from the upstream side of the one-way electromagnetic switching valve (7) and connected to the first branch pipe line (40) that connects the switching valve (7) and the regeneration heat exchanger (4). Second branch line that can be introduced
(32) is provided.

As shown in FIG. 3, the three-way solenoid valve (7) is removed and the bypass valve (9) and the first branch pipe (40) are respectively connected to the solenoid valve (3).
3) Even when (34) is provided, the same effect as the configuration shown in FIG. 2 below can be obtained.

Action / Effect When the 3-way solenoid valve (7) is switched to the bypass line (9) side (during cooling process), part of the waste gas is regenerated in the second branch line (32) and regenerated. Heater (8) through heat exchanger (4)
Is supplied to the adsorber (10) and the remaining waste gas is 3
It is supplied to the adsorber (10) directly from the bypass pipe line (9) via the one-way electromagnetic switching valve (7).

However, the pressure loss in the pipeline passing through the heat exchanger (4) for regeneration and the heater (8), especially in the second branch pipeline (32), should be larger than that in the bypass pipeline (9). By setting so that a part of the exhaust gas passes through the heat exchanger for regeneration (4) and the temperature rises but the flow rate is low, it is mixed with the exhaust gas from the bypass pipe (9). After that, the waste gas having a temperature that does not affect the cooling of the adsorbent can be supplied to the adsorber (10). Needless to say, the heater (8) at this time is stopped.

Therefore, a small amount of branching from the upstream side of the three-way electromagnetic switching valve (7) and connecting to the first branch pipe line (40) connecting the switching valve (7) and the regeneration heat exchanger (4). The second that can introduce waste gas
Due to the configuration in which the branch pipe (32) is provided, the temperature of the introduced compressed air is, for example, about 110 ° C. By bypassing the waste gas through the second branch line (32), the temperature is lowered from 110 ° C to 85 ° C and precooled.

After that, by switching the three-way electromagnetic switching valve (7) and supplying the total flow rate of the waste gas to the regeneration heat exchanger (4), the temperature in the vicinity of the waste gas inflow part is changed from about 85 ° C to 60 ° C. As a result, the temperature change amount is reduced, and the thermal shock can be significantly reduced.

In the embodiment shown in FIG. 3, thereafter, the solenoid valve (33) is closed, the solenoid valve (34) is opened, and the entire flow rate of waste gas is supplied to the heat exchanger (4) for regeneration. As a result, the amount of temperature change is similarly reduced, and the thermal shock can be significantly reduced.

Example 3 In the same configuration as the conventional regenerator shown in FIG. 4, a test was conducted using a continuous directional control valve capable of continuously increasing the amount of introduction from a small amount instead of the three-way electromagnetic directional control valve. The thermal stress near the waste gas inflow part of the heat exchanger for use was reduced to about 1/4 compared to the conventional regenerator using a three-way switching solenoid valve.

As described above, according to the present invention, in valve switching during the heating step, in Examples 1 and 2, by performing pre-cooling before valve switching or at all times, the temperature change amount (50 ° C) of the conventional device is reduced to about
Since it decreases to about 1/2 (25 ° C.), in Example 3, the thermal shock can be alleviated by switching while continuously increasing, and the thermal stress in the heat exchanger for regeneration, especially in the vicinity of the waste gas inflow portion, is reduced. Significantly reduce and prevent regeneration of thermal fatigue fracture.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a reproducing apparatus according to the present invention,
2 and 3 are circuit explanatory diagrams showing another embodiment of the present invention. FIG. 4 is a circuit diagram of a conventional reproducing apparatus. 1 ... Suction filter, 2 ... Compressor, 3 ... Purifier,
4 ... Regeneration heat exchanger, 5 ... Aftercooler, 6 ...
… Waste gas passage, 7 …… 3-way solenoid valve, 8 …… Heater, 9 …… Bypass line, 10 …… Adsorber, 10a, 10b ……
Adsorption tower, 11,12,18,19,30,31,33,34 …… Solenoid valve, 13,14,1
6,17 ...... Check valve, 15 ...... Filter, 20 ...... Exhaust tower, 32,40,41,42 …… Branch pipeline.

Claims (3)

[Claims] 1. A heat-regeneration type in which a pair of adsorption towers are arranged in parallel, and low-temperature waste gas from a main heat exchanger and waste gas heated by a regeneration heat exchanger can be introduced alternately. In the adsorber, a branch pipe that allows the waste gas to be introduced into the regeneration heat exchanger is provided upstream of the three-way switching valve that switches the waste gas from the main heat exchanger to the adsorber or the regeneration heat exchanger. The branch pipe is provided with an on-off valve, and a pipe branched from a pipe connecting the regeneration heat exchanger and the heater is connected in the middle of the pipe connecting the discharge side of the adsorber and the exhaust tower, An adsorber regeneration device in an air separation device, characterized in that an opening / closing valve is provided in the branch pipe line. 2. A heat-regeneration type in which a pair of adsorption towers are arranged in parallel, and low-temperature waste gas from the main heat exchanger and waste gas heated by the heat exchanger for regeneration can be introduced alternately. In the adsorber, upstream of the three-way switching valve that switches the waste gas from the main heat exchanger to the adsorber or the heat exchanger for regeneration, or the bypass pipe line to the adsorber or the waste gas passage to the heat exchanger for regeneration. A regeneration device for an adsorber in an air separation device, characterized in that a branch pipe line that allows a small amount of waste gas to be introduced into a regeneration heat exchanger is provided upstream of each on-off valve provided on the way. 3. A heat-regeneration type in which a pair of adsorption towers are arranged in parallel, and low-temperature waste gas from the main heat exchanger and waste gas heated by the regeneration heat exchanger can be introduced alternately. In the adsorber, a three-way switching valve for switching the waste gas from the main heat exchanger to the adsorber or the heat exchanger for regeneration is a continuous switching valve.