JPH07294161A - Pressurizing heat exchanger and low temperature gas separator - Google Patents

Abstract

PURPOSE:To perform heat exchanging even under a high pressure of source gas by providing a plate fin type compact heat exchanger, a vessel in which the compact heat exchanger is housed to maintain airtightness and means for introducing pressure gas to the vessel to apply external pressure to the compact heat exchanger. CONSTITUTION:A cold reserving box 3 is formed with a pressure-proof vessel with airtightness in which a heat exchanger 4 connected to a source gas supply line 1a and a gas/liquid separator 5 are housed and to the outer wall of which an N2 gas supply line 4a and a discharge line 4b are connected. Upon heat exchanging, high internal pressure is applied to the heat exchanger 4 because of the supply of high pressure source gas. In order to meet it, pressure N2 gas is supplied to the cold reserving box 3, so that large internal and external pressure difference applied to the wall of the heat exchanger is reduced. Accordingly, even when the pressure of the supplied source gas exceeds 100kg/cm<2> G, the compact heat exchanger excellent in heat transfer performance can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a heat exchanger used for heat exchange between gases, and the use of the heat exchanger to remove impurity components from a raw material gas by an adsorption separation method and further purify the purified gas. The present invention relates to a cryogenic gas separation device for separating a gas of a target component using a cryogenic separation method.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a cryogenic gas separation apparatus of this type mainly includes adsorbers 50a and 50b, an adsorber regeneration heater 51, a gas-liquid separator 52, a heat exchanger 53 and a cool box. 54, for example, H ₂ : 60, C
H _4: 40 H from the raw material gas purity of 95% of (the vol%)
_When purifying _two gases, first, the raw material gas is introduced into the heat-regeneration type adsorbers 50a and 50b, and impurity components in the raw material gas, such as H ₂ O, CO ₂ , C ₆ H ₆ , and NH _3, are removed. Adsorbed and removed.

The purified gas from which the impurity components have been removed in this way is introduced into the heat exchanger 53 provided in the cold insulation box 54 and cooled. In this heat exchanger 53, the purified gas is-
It is cooled to 150 ° C. to −190 ° C., whereby the components other than H ₂ (CH _{4 in} this case) are condensed into a liquid.
Thus the process gas is concentration of H ₂ rises by components other than H ₂ decreases, resulting in a purity of 95% H ₂
Gas will be obtained. The H ₂ gas having a purity of 95% is again introduced into the heat exchanger 53 to cool the raw material gas introduced next, and thereby becomes the room temperature gas to become the product H ₂ gas.
It becomes gas. The liquefied CH ₄ has its temperature lowered by expansion utilizing the Joule-Thomson effect, is again introduced into the heat exchanger 53 and cools the raw material gas introduced next in the same manner as described above, and thereby the normal temperature gas Becomes

Cooling box 5 containing the heat exchanger 53
No. 4 is filled with granular pearlite as a heat insulating material for the purpose of insulating low-temperature equipment, and the internal pressure is usually 0.01 kg / cm ² G low pressure (N ₂ seal without pressure).
Has become. As the configuration of the heat exchanger 53, an aluminum plate fin type compact heat exchanger is generally used because it is compact, has excellent heat transfer performance, and is optimal as a fluid heat exchanger. The compact heat exchanger is configured so that the volume of the heat exchanger is made as small as possible and the large heat transfer area is suppressed, and the ratio of the heat transfer area to the volume is 200 or more.

[0005]

However, in such a conventional aluminum plate fin type compact heat exchanger, the use limit is up to a pressure of about 100 kg / cm ² G,
Therefore, when the pressure of the raw material gas introduced into the heat exchanger becomes higher than that, there is a problem that the aluminum plate fin type heat exchanger cannot be used. Specifically, a crack is generated in the aluminum fin portion and the heat exchanger is destroyed. As a means for solving the structural problem of the aluminum plate fin type, it is possible to use a shell coil type heat exchanger instead of the aluminum plate fin type. However, in this shell coil type, the size of the heat exchanger becomes large and it cannot be made compact,
In addition, there is a new problem that the cost becomes high.

The present invention has been made in consideration of the above problems in the conventional cryogenic gas separation device, and the plate is introduced even when the pressure of the introduced raw material gas exceeds 100 kg / cm ² G. It is an object of the present invention to provide a pressurization type heat exchanger capable of performing gas separation using a fin type compact heat exchanger and a deep-chill gas separation device using the same.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a compact plate fin type heat exchanger, a container for accommodating the compact heat exchanger and capable of maintaining an airtight state, and introducing a pressurized gas into the container to achieve a compact size. And a pressurizing means for applying an external pressure to the heat exchanger.

According to the present invention, the impurity components in the raw material gas are removed by the adsorber, and the gas from which the impurity components have been removed is cooled by the plate fin type heat exchanger so that the components other than the target components are condensed. And remove or rectify the cooled gas to recover the obtained target component gas,
Alternatively, in a refrigerating gas separation device of a structure for refining, a container that can hold a plate fin type heat exchanger and can maintain an airtight state, and a pressurized gas is introduced into the container, and the plate fin type heat exchanger A cryogenic gas separation device comprising: a pressurizing means for applying an external pressure. In the present invention, it is preferable to further provide a discharging means capable of discharging the raw material gas in the plate fin type heat exchanger when the pressure in the container decreases.

As an example of the discharging means in the present invention,
A safety valve provided in a raw material gas introduction passage connected to the container inlet side is shown, and the safety valve can be configured to open by a decrease in gas pressure in the container.

Another example of the discharging means is a control valve provided in the raw material gas introduction path connected to the container inlet side,
A pressure switch provided in the container for detecting the internal pressure of the container and outputting a signal when the pressure in the container drops from a predetermined value; and a control means for receiving the signal output from the pressure switch and opening the control valve. , Can also be configured.

[0011]

In the present invention, the gas is introduced to pressurize the inside of the plate fin type compact heat exchanger. In opposition to this, the pressurizing means moves the pressurized gas into the container (outside the heat exchanger). Since it is introduced, the pressure difference between the inner and outer sides of the plate fin type heat exchanger is relaxed, and it is possible to prevent stress from concentrating on the fins and the fin-plate joints. Can be introduced into the heat exchanger.

In the present invention, the impurity components in the raw material gas are removed by the adsorber, and the gas from which the impurity components have been removed is further cooled by the plate fin type heat exchanger so that components other than the desired component gas are removed. It is condensed and separated and removed.
At the time of heat exchange, the inside of the plate fin type heat exchanger is pressurized by the introduction of the raw material gas, but against this, the pressurized gas is introduced into the container (outside the heat exchanger) by the pressurizing means. The pressure difference between the inner and outer sides of the plate fin type heat exchanger can be relaxed and stress can be prevented from concentrating on the fins and the fin-plate joints. Can be introduced to. Further, according to the present invention, when the pressure in the container decreases, the pressure in the heat exchanger can also be decreased at the same time, and therefore damage to the heat exchanger can be avoided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a basic configuration diagram showing an embodiment of the cryogenic gas separation device of the present invention. In the figure, the cryogenic gas separation device is connected to the adsorbers 2a and 2b into which the raw material gas is introduced through the raw material gas supply line 1 and the outlet side of the adsorbers 2a and 2b through the raw material gas introduction line 1a. The cold storage box 3 as a container is basically provided, and the configuration of the pretreatment to reach the cold storage box 3 is basically the same as the configuration of the conventional deep-cooled gas separation device.

In the cryogenic gas separation apparatus having such a structure, for example, from the source gas containing H ₂ and CH ₄ as main components,
_{When the two} gases are separated and purified, first, the impurity components in the raw material gas, such as H ₂ O, CO ₂ , C ₆ H ₆ , and NH _3, are removed by the adsorbers 2a and 2b. The gas from which the impurities have been removed is introduced into the heat exchanger 4 provided in the cold insulation box 3 and cooled, and the components other than the target recovery component H ₂ (CH _{4 in} this case) are condensed into a liquid. Be removed. Therefore, the processing gas is reduced in components other than H ₂ , and is further passed through the heat exchanger 4 to be a room temperature gas to obtain a product H ₂ gas.

Next, the structure of the cool box 3 including the heat exchanger, which is a characteristic part of this embodiment, will be described. The cool box 3
It is composed of a pressure-tight container having airtightness, and contains therein a heat exchanger 4 connected to the raw material gas introduction line 1a and a gas-liquid separator 5 connected to the heat exchanger 4, and a cool box 3 An N ₂ gas introduction line 4a for introducing high-pressure N ₂ gas is connected to the outer wall of, and a discharge line 4b for discharging N ₂ gas is connected to the opposite side. As the high-pressure N ₂ gas can be supplied to the N ₂ gas to a high pressure or using a high pressure N ₂ gas other processing system, or in another facility. This N ₂ gas and N ₂ gas introduction line 4a
Can be seen as a pressurizing means. As the heat exchanger 4 housed in the cool box 3, a compact aluminum plate fin type heat exchanger that is compact and has excellent heat transfer performance is used. The operation of this embodiment having such a configuration will be described below.

As described above, the gas from which the impurity components have been removed is cooled by the aluminum plate fin type heat exchanger ₄ to condense components other than the target component H ₂ gas (for example, CH ₄ ). Separated. When the heat is exchanged, a high pressure source gas is introduced from the source gas introduction line 1a, so that the aluminum plate fin type compact heat exchanger 4 receives a large internal pressure. Since the N ₂ gas is introduced into the cold insulation box 3, a large pressure difference between the inside and the outside applied to the wall of the aluminum plate fin type compact heat exchanger 4 is reduced.

For example, the pressure of the source gas is 120 kg / cm ² G
If the gas pressure in the cool box 3 is 30 kg / cm ² G, the internal pressure applied to the aluminum plate fin type heat exchanger 4 is substantially 90 kg / cm ² G, and the aluminum plate fin type heat exchange is performed. It will be less than 100 kg / cm ² G which is the limit of use of the vessel. Therefore, the pressure of the raw material gas to be introduced is 100 kg.
Even if it exceeds / cm ² G, it is possible to use an aluminum plate fin type compact heat exchanger that is excellent in heat transfer performance and compact.

As described above, even if the raw material gas having a higher pressure than usual is introduced, by allowing the inside of the cold-insulating box 3 to be pressurized, the N ₂ gas pressure in the cold-insulating box 3 decreases. In that case, it is necessary to interrupt the introduction of the raw material gas and immediately discharge the raw material gas in the heat exchanger 4. Hereinafter, two forms for discharging will be described. The first discharging means is provided with a safety valve, and the second discharging means is provided with a control valve operated by the control device.

FIG. 2 shows the structure of the first discharge means, and 10 is a safety valve provided in the source gas introduction line 1a, the outlet side of which communicates with the inside of the cool box 3. . When the inside of the cold-insulating box 3 is at a predetermined pressure, the safety valve 10 uses the gas pressure as a back pressure to keep the safety valve 10 inoperative together with the urging force of the spring, but when the pressure in the cold-insulating box 3 decreases. The back pressure acting to close the safety valve 10 is reduced and the safety valve 10 is opened. Therefore, when the pressure in the cool box 3 decreases, the safety valve 10 opens and the pressure of the raw material gas decreases, and the raw material gas in the heat exchanger 4 is discharged from the safety valve. A safety valve 11 is provided in the cool box 3 so that the N ₂ gas pressure in the cool box 3 can be discharged. As a result, when the pressure inside the cool box 3 decreases, the pressure inside the heat exchanger 4 also decreases, and thus damage to the heat exchanger 4 can be avoided.

FIG. 3 shows the structure of the second discharging means, which is provided in a branch line 1d which is branched from a raw material gas introduction line connected to the inlet side of the cold insulation box 3. Emergency release valve 12 as a control valve, and a cool box 3
Attached to a pressure switch 13 that detects its internal pressure and outputs a signal when the pressure inside the cool box 3 drops from a predetermined value, and receives the signal output from the pressure switch 13 to shut off the raw material introduction line. Valve 14, emergency release valve 12,
Product recovery line shutoff valve 15, exhaust gas recovery line shutoff valve 1
6 and a control section 17 as a control means for controlling the opening / closing operation of each.

According to this construction, the pressure drop in the cool box 3 is detected by the pressure switch 13, and the pressure switch 1
The signal output from 3 is given to the control unit 17, and the control unit 17 receives the signal and closes the raw material introduction line shutoff valve 14 to open the emergency release valve 12, and the product recovery line shutoff valve 1
5. Close the exhaust gas recovery line shutoff valve 16 together. With such a configuration, even if the pressure in the cold insulating box 3 is reduced, the pressure in the heat exchanger 4 is also reduced, so that the heat exchanger 4 can be prevented from being damaged. In addition,
Specifically, the pressure switch can be composed of a pressure gauge with a contact or the like.
The exhaust gas recovery line shutoff valve 16 may be a check valve. The control unit 17 may be composed of a microcomputer or a hard relay circuit equivalent thereto. Further, the pressurizing heat exchanger of the present invention is not limited to the deep-cooled gas separation device of the above-mentioned embodiment, but can be applied to a device for exchanging heat between gas with relatively little contamination.

[0022]

As is apparent from the above description, according to the present invention, since the structure for pressurizing the inside of the container is provided, the pressure difference between the inside and outside of the plate fin type compact heat exchanger can be reduced. As a result, it is possible to introduce a gas having a pressure exceeding the pressure limit of the heat exchanger to exchange heat.

Since the cryogenic gas separation apparatus of the present invention has a structure in which the heat exchanger is housed in the container and pressurizes the inside of the container, the pressure resistance of the plate fin type heat exchanger is adopted. Even if a raw material gas having a high pressure exceeding the limit is introduced, it has an advantage that it is possible to perform the cryogenic gas separation. Further, according to the present invention, when the pressure in the container decreases, the internal pressure in the heat exchanger can also be decreased at the same time, so damage to the heat exchanger can be avoided.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a first configuration of a blocking means according to an embodiment.

FIG. 3 is an explanatory diagram showing a second configuration of the blocking means according to the embodiment.

FIG. 4 is a configuration diagram of a conventional cryogenic gas separation device.

[Explanation of symbols]

1 Raw material gas supply line 1a Raw material gas introduction line 2a, 2b Adsorber 3 Cold box 4 Heat exchanger 4a N ₂ Gas introduction line 4b Discharge line 5 Gas-liquid separator

Claims (5)

[Claims] 1. A plate fin type compact heat exchanger, a container capable of housing the compact heat exchanger and maintaining an airtight state, and introducing a pressurized gas into the container, and And a pressurizing means for applying external pressure to the pressurizing heat exchanger. 2. An impurity component in the raw material gas is removed by an adsorber, and the gas from which the impurity component is removed is cooled by a plate fin type heat exchanger, whereby components other than the target component are condensed and separated. A refrigeration gas separation device configured to rectify and separate a gas that has been removed or cooled and recover or purify the obtained target component gas, in which an airtight state is maintained by housing the plate fin type heat exchanger. A cryogenic gas separation device, comprising: a container capable of controlling the pressure, and a pressurizing means for introducing a pressurized gas into the container to apply an external pressure to the plate fin type heat exchanger. 3. The cryogenic gas separation apparatus according to claim 2, further comprising an exhausting unit for exhausting the raw material gas in the plate fin type heat exchanger when the pressure in the container decreases. 4. The discharge means is composed of a safety valve provided in a raw material gas introduction path connected to the container inlet side, and the safety valve is opened by a decrease in gas pressure in the container. The cryogenic gas separation device according to claim 3. 5. The discharge means is provided in a raw material gas introduction path connected to the container inlet side, and is provided in the container, detects the internal pressure of the container, and detects the internal pressure of the container. 4. A pressure switch that outputs a signal when is decreased from a predetermined value, and a control unit that receives the signal output from the pressure switch and opens the control valve. Cryogenic gas separator.