KR20230106782A - PSA system for efficient separation of impurities from source gas including main gas and impurities, and operating method there of - Google Patents

Abstract

The present invention relates to a PSA system for efficient separation of impurities from main gas and raw material gas including impurities and an operating method thereof, and more specifically, to a PSA system for efficient separation of impurities from main gas and raw material gas including impurities and an operating method thereof, wherein the system separates impurities contained in raw material gas, that is, exhaust gas is recycled into regenerated gas in a PSA process, and each PSA process is combined and operated.

Description

PSA system for efficient separation of impurities from source gas including main gas and impurities, and operating method there of}

The present invention relates to a PSA system for efficiently separating impurities from a source gas including a main gas and impurities, and an operating method thereof, and more particularly, to a system for separating impurities contained in a source gas, that is, in a PSA process. A PSA system for efficient separation of impurities from a source gas containing a main gas and impurities, which recycles exhaust gas into regeneration gas and also operates the respective PSA processes together, and its It's about how to drive.

Separation of the main gas from the source gas containing impurities is important in industrial processes. In general, a process using an adsorption method is used to remove impurities in a raw material gas including a main gas.

Industrial separation of impurities from raw gas is related to, for example, the purification of hydrogen. Commercial-scale processes exist to separate nitrogen and ammonia from hydrogen, especially for the purification of hydrogen.

The reason why such a commercial scale is required is that hydrogen does not contain carbon (C) atoms, so it does not emit carbon dioxide (CO ₂ ) as a by-product when used as energy, and is an environmentally friendly fuel that does not emit harmful gases.

In particular, since hydrogen does not exist independently in nature, it is characterized in that it must be extracted from natural resources. Hydrogen production is easily possible by electrolysis of water, but currently, a method of producing hydrogen from fossil fuels such as petroleum, natural gas, and coal is mainly used due to problems such as economic feasibility. However, since these fossil fuels contain carbon (C), it is difficult to view them as environmentally friendly. Recently, ammonia (NH ₃ ), which does not contain carbon (C), has been newly spotlighted as a fuel for hydrogen production.

2NH ₃ -> 3H ₂ + N ₂

Hydrogen production based on ammonia includes a decomposition reaction process as shown in the above reaction equation, and the gas generated through the reaction process includes nitrogen as a by-product and unreacted ammonia in addition to hydrogen.

On the other hand, ammonia is highly corrosive and can be vulnerable to materials, and adversely affects an electrolyte membrane or a catalyst layer in a fuel cell, which is a major use. In addition, nitrogen is generally known to be stable as a representative inert gas, but nitrogen contained in high-purity hydrogen may generate ammonia at high temperatures, and may adversely affect the PEMFC stack at low temperatures by being adsorbed.

In addition, nitrogen emitted through ammonia decomposition contains a large amount of about 25 mol%, which not only increases the size of the process inefficiently, but also increases the hydrogen used in fuel cells for vehicles when nitrogen is included in the hydrogen used as a raw material for fuel cells. Since the concentration of hydrogen supplied to the inlet of the stack is low, such as accumulated in the recirculation system, eventually deteriorating the performance of the stack, it must be removed.

As such, the removal of impurities is an important part of the high-purity hydrogen production system.

On the other hand, the adsorption method is known as the most effective method for removing impurities in the prior art.

In particular, the separation process using the adsorption method is performed at a relatively low temperature, and the adsorbent has high competitiveness because it has selectivity for a specific material. On the other hand, in order for the adsorption method to be a continuous process, the adsorbent must be effectively regenerated. Methods for regenerating the adsorbent include a temperature swing adsorption (TSA) method that regenerates the adsorbent by raising the temperature and a pressure swing adsorption method that regenerates the adsorbent by adjusting the pressure. (Pressure Swing Adsorption, PSA).

The TSA method includes a complicated step of repeating re-adsorption by raising the temperature to a certain temperature to desorb the adsorbed gas and then lowering the temperature back to room temperature to regenerate the adsorbent. On the other hand, the PSA method is a method of separating and purifying impurities based on the principle that the adsorption amount changes according to pressure, and the operation is simple and the processing time is short.

However, when an impurity included in the mixture gas has a strong bond with the adsorbent, such as ammonia, it is difficult to desorb and the recovery rate of the purified main gas, that is, hydrogen, is low.

For this reason, in the prior art, ammonia is removed from hydrogen by applying the TSA method.

In general, PSA is based on a cycle operation of steps including adsorption and desorption, and the shorter the cycle time, the higher the purity of the main gas, for example, hydrogen, but the recovery efficiency of hydrogen is low. In order to increase the recovery efficiency of the main gas, a method of lowering the pressure in the desorption step by using a vacuum pump (VPSA) has been used, but it has the disadvantage of requiring an additional device.

In addition, the adsorbent filled in the PSA causes a difference in operation process due to a difference in performance according to each impurity, that is, a difference in performance when removing ammonia and when removing nitrogen.

Therefore, a method of connecting each PSA capable of removing each impurity is required.

On the other hand, when two or more PSAs are connected in series and used, the overall recovery efficiency of the connected process may be reduced due to the recovery efficiency of each PSA, and the performance of the PSA may be reduced due to the difference in the circulation process in each PSA. .

Therefore, in order to improve the purity and recovery efficiency of the main gas in the source gas, for example, hydrogen, a system capable of stably operating a PSA capable of efficiently separating and removing impurities such as ammonia and nitrogen, and an operating method thereof need to develop

KR 10-2315763 B1(2021.10.21. Announcement)

The present invention combines each PSA system used for separation of two or more types of impurities included in the main gas for high purity and high efficiency separation and purification of the main gas from the raw material gas containing impurities, and also, the PSA system is used for regeneration gas It is an object of the present invention to provide a PSA system for efficiently separating impurities from a source gas including a main gas and impurities, and an operation method thereof, for the purpose of efficiently separating impurities from a main gas by utilizing a rinse gas.

The present invention, for the purpose of high-purity and high-efficiency separation and purification of the main gas from the source gas as described above, to provide a PSA system for efficient separation of impurities from a source gas containing a main gas and impurities, and an operation method thereof is to do

The PSA system for efficient separation of impurities from the source gas containing the main gas and impurities of the present invention,

It includes n PSA units for removing n respective impurities from the raw material gas, that is, the first PSA unit 100 to the n th PSA unit 200, and a control tank unit 300 (see FIG. 1).

The control tank unit may include 1 to n-1 units.

The PSA unit includes a source gas supply unit including a main gas and impurities; two or more adsorption towers filled with an adsorbent adsorbing impurities; Refined gas outlet from which impurities are removed; An exhaust gas discharge unit containing the removed impurities; and, if necessary, a regeneration gas supply unit; and a vacuum pump for detachment (see FIG. 2).

The first PSA unit is a PSA unit for removing a first impurity from the raw material gas, the n−1 th PSA unit is a PSA unit for removing an n−1 th impurity, and the n th PSA unit is an n th impurity. It is a PSA part for finally separating and purifying the main gas by removing the

The first PSA unit includes a source gas supply unit containing all impurities; two or more adsorption towers filled with an adsorbent adsorbing the first impurity; a refined gas discharge unit from which the first impurities are removed; and an exhaust gas discharge unit including the removed first impurities, and a second PSA unit including the source gas supply unit excluding the first impurities; two or more adsorption towers filled with an adsorbent adsorbing the second impurity; a refined gas outlet from which the second impurities are removed; and an exhaust gas discharge unit including the removed second impurities, wherein the n-th PSA unit includes the source gas supply unit excluding the n−1-th impurities; two or more adsorption towers filled with an adsorbent adsorbing the nth impurity; a purified gas discharge unit from which nth impurities are removed; and an exhaust gas discharge unit including the removed n-th impurity (see FIG. 2).

Two or more adsorption towers are configured to cycle through a pressurization step, an adsorption step, a decompression step, and a regeneration step. An equalization step may be included in this operation if desired (see Figure 3).

The pressurizing step is a step for increasing the pressure in the adsorption tower to the pressure of the adsorption step. The pressurization step may use source gas or refined gas.

The adsorption step is a step of discharging the purified gas to the top of the adsorption tower at a constant adsorption pressure following the pressurization step. Inside the adsorption tower, mass transfer occurs according to the difference in concentration between the impurity, which is a strong adsorbate, and the main gas, which is a weak adsorbate. will be ejected The gas flow in the adsorption tower proceeds from the bottom of the adsorption tower to the top.

The decompression step is a step of desorbing impurities saturated in the adsorption tower by lowering the pressure of the adsorption tower after the adsorption step. The valve at the bottom of the adsorption tower is opened to lower the pressure from the high pressure, which is the adsorption pressure, to the low pressure, which is the desorption pressure. At this time, a vacuum pump can be used to increase the desorption efficiency. The gas flow in the adsorption tower proceeds from the top of the adsorption tower to the bottom, in the opposite direction to the adsorption step.

The regeneration step is a step for achieving complete regeneration of the adsorption tower by desorbing impurities remaining in the adsorption tower after the depressurization step. In this regeneration step, the regeneration gas is injected into the upper part of the adsorption tower at a low pressure for cleaning, and the gas is discharged to the lower part of the adsorption tower to lower the concentration of impurities in the adsorption tower.

The regeneration gas is used by using a part of the refining gas or by supplying a separate weak adsorbate gas. The flow rate of the commonly used regeneration gas is an important variable affecting the purity of the refined gas and the recovery rate of the main gas.

The equalization step is a step of reducing energy loss by using some of the energy (pressure) lost in the pressure reduction step. That is, the adsorption tower after the adsorption step is connected to another adsorption tower after the regeneration step, so that the high-pressure adsorption tower after the adsorption step is subjected to cocurrent pressure reduction and the adsorption tower after the regeneration step is subjected to countercurrent pressure simultaneously. Energy loss can be reduced by using some of the energy for pressurization of other adsorption towers. When the equalization step is included, the adsorption tower of the PSA unit may be circulated and operated in the order of pressurization step, adsorption step, equalization step (co-current pressure reduction), decompression step, regeneration step, and equalization step (countercurrent pressure).

In the case of the source gas supply unit, the first PSA unit supplies source gas containing all impurities, the second PSA unit supplies source gas excluding the first impurity, and the n-th PSA unit supplies source gas containing all impurities from the first impurity to the nth PSA unit. This is a place to supply source gas excluding n-1 impurities up to the n-1th impurity.

The refined gas discharge unit, in the case of the first PSA unit, discharges the refined gas from which the first impurities are removed, and the discharged refined gas is source gas supplied to the source gas supply unit of the second PSA unit. Accordingly, the refined gas discharge unit of the nth PSA unit discharges refined gas from which n impurities are removed, that is, a main gas from which all impurities are removed is discharged.

In the case of the first PSA unit, the exhaust gas discharge unit discharges exhaust gas mainly composed of the removed first impurity out of raw material gas containing all impurities, and in the case of the second PSA unit, the refined gas from which the first impurities are removed. This is where the exhaust gas containing the removed second impurity as a main component is discharged. Therefore, the exhaust gas discharge unit of the n-th PSA unit discharges exhaust gas mainly composed of the n-th impurities removed from the purified gas from which n-1 impurities are removed, that is, it does not contain n-1 impurities.

In addition, the first PSA unit to the n−1 th PSA unit may include a regeneration gas supply unit. The regeneration gas supply unit of the first PSA unit to the n-1th PSA unit supplies a regeneration gas for regeneration of the adsorption tower of each PSA unit (see FIG. 4 ).

As the regeneration gas, one or more of exhaust gases discharged from the second PSA unit to the n-th PSA unit may be used for the first PSA unit to the n−1 th PSA unit (see FIG. 4 ).

However, gas containing impurities to be removed from each PSA cannot be used as a regeneration gas. For example, as the regeneration gas utilized in the first PSA unit, one or more of the exhaust gases of any one of the second PSA unit to the n-th PSA unit may be selected and used, but the n-th PSA unit may be used by selecting one or more exhaust gases from the first PSA unit to the n-th PSA unit. 1 Exhaust gas from the PSA section cannot be used as regeneration gas.

The connection of the PSA units can be connected in series in the form of “refined gas discharge unit - refined gas control unit - feed gas supply unit”, in order from impurities of strong adsorption material to weak adsorption material. Remove sequentially. For example, when the impurities are ammonia and nitrogen, the first PSA removes the ammonia impurity, which is a strong adsorbate, and the second PSA unit removes the nitrogen impurity, which is a weaker adsorbate than ammonia (see FIG. 5).

The control tank unit 300 may be located between each PSA unit, and is for mitigating pressure pulsation generated when connecting each PSA unit.

Each of the control tank units 300 may include a refinery gas control unit 310 and a regeneration gas control unit 320 (see FIG. 6 ).

The refinery gas controller 310 includes one or more refinery gas buffer tanks 311; refinery gas control system 312; and a refinery gas discharge unit 313.

The refinery gas discharge unit 102 of the n−1th PSA unit 100 and the source gas supply unit 201 of the nth PSA unit 200 are connected to the refinery gas buffer tank 311 (n is 2 or more). is an integer).

That is, when there are n PSA units to be connected to the refined gas controller 310, n−1 refined gas controllers 310 are required (see FIG. 9). The refinery gas buffer tank 311 may include one or more tanks as needed.

The refinery gas discharge unit 313 is connected to the upper end of the refinery gas buffer tank 311, and the refinery gas control system 312 is installed in the refinery gas discharge unit 313 to equalize the pressure, That is, the raw material gas supply unit (201 ) acts as a transfer.

The regeneration gas controller 320 includes one or more regeneration gas buffer tanks 321; regeneration gas control system 322; and a regeneration gas discharge unit 323.

The regeneration gas buffer tank 321 is connected to the regeneration gas supply unit 302 of the n−1 th PSA unit 100 and the exhaust gas discharge unit 301 of the n th PSA unit 200 (n is 2 or more). is an integer). In addition, one or more tanks may be included in the regeneration gas buffer tank 321 as needed.

When there are n PSA units to be connected, one or more and n−1 or less regeneration gas controllers 320 may be installed according to the method of using the exhaust gas (see FIG. 10 ).

The regeneration gas discharge unit 323 is connected to the upper end of the regeneration gas buffer tank 321, and the regeneration gas control system 322 is installed in the regeneration gas discharge unit 323 to equalize the pressure, That is, the regeneration gas supply unit 302 of the n-1th PSA unit 100 is stably reduced by reducing the pressure fluctuation range of the exhaust gas discharge unit 301 of the n-th PSA unit 200 injected into the regeneration gas buffer tank 321. ) acts as a transfer.

The refinery gas control system 312 and the regeneration gas control system 322 include a pressure transmitter and a control valve. The control valve operates by reading the output value of the pressure transmitter according to the set pressure, and the refining gas control system 312 and the regeneration gas control system 322 are automatically controlled to the set pressure.

According to the present invention, when purifying with high purity by connecting PSA systems adsorbing each impurity from a main gas and a raw material gas containing two or more impurities, the exhaust gas of the downstream PSA is converted into regeneration gas in the regeneration step of the preceding PSA. By using it, it provides an economical system connection method without adding a separate regeneration gas supply system while reducing the loss of refined gas and not reducing the recovery efficiency of the main gas.

In addition, a high-purity purification system that operates stably is provided by merging and connecting gases discharged from the PSA system to the control tank unit.

As an example, the high-purity purification system of the present invention can be applied to an ammonia-based hydrogen production system, and the system that can produce high-purity hydrogen by efficiently removing by-products (ammonia, nitrogen, etc.) generated from the ammonia decomposition reaction can be operated stably. There are advantages to providing a method.

1 shows a representative configuration of a PSA system according to the present invention.
2 shows the configuration of each PSA unit of the present invention.
Figure 3 shows the gas flow at each stage of the adsorption tower configured in the PSA unit.
Figure 4 shows an exemplary PSA system according to the present invention in the case of a source gas containing three or more impurities.
5 shows a PSA system according to the present invention when the main gas is hydrogen and the impurities are ammonia and nitrogen.
FIG. 6 illustrates a detailed configuration of the control tank unit of FIG. 1 .
7A shows a method of operating the PSA system of the present invention.
Figure 7b shows another method of operation (including an equalization step) of the PSA system of the present invention.
Fig. 8 shows the device configuration of the embodiment.
9 illustrates the configuration of a refinery gas control unit when the number of PSA units is n.
10 illustrates the configuration of a regeneration gas control unit when there are n PSA units.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention. At this time, the terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor appropriately defines the concept of terms in order to explain his/her invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

An object of the present invention is to provide a PSA system for efficient separation of impurities from a main gas and source gas containing impurities, and an operating method thereof.

In the following, the present invention will be described using drawings and specific examples.

The configuration of the PSA system proposed in the present invention is shown in FIG. The PSA system includes a first PSA unit 100; second PSA section 200; and a control tank unit 300.

The source gas including the main gas and impurities is injected into the source gas supply unit 101 of the first PSA unit 100 to remove one of the impurities, and then the refinery gas discharge unit 102 of the first PSA unit 100 is emitted with The discharged gas is injected into the raw material gas supply unit 201 of the second PSA unit 200 via the refined gas control unit 310 of the control tank unit 300, and after the other one of the impurities is removed, the second PSA unit ( 200) is discharged to the refined gas discharge unit 202.

The gas mainly composed of impurities removed by the second PSA unit 200 is discharged to the exhaust gas discharge unit 301 of the second PSA unit 200 . The discharged gas is injected into the regeneration gas supply unit 302 of the first PSA unit 100 via the regeneration gas controller 320 of the control tank unit 300 . The injected gas is discharged to the exhaust gas discharge unit 103 of the first PSA unit 100 together with gas mainly composed of impurities removed by the first PSA unit 100 .

The configuration of each PSA section is shown in FIG. 2 . Each of the PSA units includes two or more adsorption towers filled with an adsorbent adsorbing impurities, and a source gas supply unit including a main gas and impurities; and a purified gas discharge unit from which impurities are removed is connected to the upper portion of the adsorption tower, and an exhaust gas discharge unit containing the removed impurities as a main component is connected to the lower portion of the adsorption tower. If necessary, a regeneration gas supply unit at the top of the adsorption tower; And it may include a vacuum pump for desorption at the bottom of the adsorption tower.

Two or more adsorption towers are configured to cycle through a pressurization step, an adsorption step, a decompression step, and a regeneration step. An equalization step may be included in this operation if desired (see Figure 3).

The pressurization step is a step for increasing the pressure in the adsorption tower to the pressure of the adsorption step, and generally, the shorter the time, the better the performance. In addition, the pressurization step includes a source gas pressurization method using a source gas and a refining gas pressurization method using a part of the refined gas obtained through refining. In general, since the refinery gas is weaker adsorbate than the source gas, the refinery gas pressurization method increases the purity of the refinery gas, but the recovery rate of the main gas decreases by the amount of the refinery gas used in the pressurization step.

The adsorption step is a step of discharging the purified gas to the top of the adsorption tower at a constant adsorption pressure following the pressurization step. Inside the adsorption tower, mass transfer occurs according to the difference in concentration between the impurity, which is a strong adsorbate, and the main gas, which is a weak adsorbate. will be ejected The gas flow in the adsorption tower proceeds from the bottom of the adsorption tower to the top.

The decompression step is a step of desorbing impurities saturated in the adsorption tower by lowering the pressure of the adsorption tower after the adsorption step. The valve at the bottom of the adsorption tower is opened to lower the pressure from the high pressure, which is the adsorption pressure, to the low pressure, which is the desorption pressure. At this time, a vacuum pump can be used to increase the desorption efficiency. The gas flow in the adsorption tower proceeds from the top of the adsorption tower to the bottom, in the opposite direction to the adsorption step.

The regeneration step is a step for achieving complete regeneration of the adsorption tower by desorbing impurities remaining in the adsorption tower after the depressurization step. In this regeneration step, the regeneration gas is injected into the upper part of the adsorption tower at a low pressure for cleaning, and the gas is discharged to the lower part of the adsorption tower to lower the concentration of impurities in the adsorption tower. The regeneration gas is used by using a part of the refining gas or by supplying a separate weak adsorbate gas. The flow rate of the regeneration gas used is an important variable that affects the purity of the refined gas and the recovery rate of the main gas.

The equalization step is a step in which energy loss can be reduced by using some of the energy (pressure) lost in the pressure reduction step. That is, the adsorption tower after the adsorption step is connected to another adsorption tower after the regeneration step, so that the high-pressure adsorption tower after the adsorption step is subjected to cocurrent pressure reduction and the adsorption tower after the regeneration step is subjected to countercurrent pressure simultaneously. Energy loss can be reduced by using some of the energy for pressurization of other adsorption towers. When the equalization step is included, the adsorption tower of the PSA unit is circulated and operated in the order of pressurization step, adsorption step, equalization step (co-current pressure reduction), decompression step, regeneration step, and equalization step (countercurrent pressure).

For example, when the number of impurities included in the source gas is two, the refined gas discharged from the refined gas discharge unit 202 of the second PSA unit 200 becomes a high-purity main gas. When the number of impurities included in the raw material gas is three or more, a control tank unit and a PSA unit connected from the refined gas discharge unit 202 of the second PSA unit 200 are additionally required.

4 shows a PSA system of the present invention that can be applied when the number of impurities included in the source gas is three or more.

As seen in Figure 4. The connection of each PSA part is serially connected in the form of “Refined Gas discharge part - Refined gas control part - Feed Gas supply part”, and if there are n PSA parts to be connected, n-1 refined gas control part (310) is included (n is an integer greater than or equal to 2).

In addition, the exhaust gas discharged from each PSA unit can be used as regeneration gas by connecting it in the form of “Exhaust Gas Discharge Unit - Regeneration Gas Control Unit - Rinse Gas Supply Unit”, and the PSA to be connected can be used as a regeneration gas. In the case of n, one or more regeneration gas controllers 320 are included according to the method to use the exhaust gas (n is an integer of 2 or more). However, exhaust gas containing impurities to be removed from the PSA unit including the regeneration gas supply unit cannot be used as the regeneration gas. That is, at least one of the exhaust gas of the second PSA unit to the nth PSA may be selected and used as the regeneration gas of the first PSA unit (n is an integer greater than or equal to 3). However, the exhaust gas of the n−1th PSA unit to the first PSA unit cannot be used as the regeneration gas of the nth PSA unit (n is an integer greater than or equal to 2).

In addition, when two or more PSA units for removing the impurities are connected, each PSA unit is connected so that impurities in the strong adsorbate are sequentially removed in the order of impurities in the weak adsorbate. For example, when the impurities are ammonia and nitrogen, the first PSA removes the ammonia impurity, which is a strong adsorbate, and the second PSA unit removes the nitrogen impurity, which is a weaker adsorbate than ammonia. The example PSA system is shown in FIG. 5 .

Hereinafter, the present invention will be described with specific examples.

That is, efficient removal of impurities from a raw material gas containing the main gas and impurities is performed by separating and refining the main gas hydrogen with high purity and high efficiency by separating ammonia and nitrogen as the impurities from a mixed gas of ammonia, hydrogen, and nitrogen as the source gas. It is intended to provide a PSA system for separation, and an operating method thereof.

In the case of purifying hydrogen by separating ammonia and nitrogen as impurities from a mixture of ammonia, hydrogen, and nitrogen as source gases as the specific example, the PSA system includes a first PSA (100) for separating ammonia; a second PSA unit 200 separating nitrogen; and a control tank unit 300. The first PSA unit 100 and the second PSA unit 200 are connected in series, and the control tank unit 300 is installed to connect the first PSA unit 100 and the second PSA unit 200. Yes (see Figs. 1 and 5).

The first PSA unit is a device for separating and removing ammonia from a source gas containing ammonia and nitrogen, including a source gas supply unit 101 containing hydrogen, ammonia, and nitrogen; A purified gas outlet 102 from which ammonia is removed; An exhaust gas discharge unit 103 and a regeneration gas supply unit 302 mainly composed of the removed ammonia.

In addition, the first PSA unit 100 consists of two or more containers filled with an adsorbent ('adsorbent A') for adsorbing ammonia, and the adsorbent is used for adsorption time and desorption time (pressurization, decompression, and regeneration steps) of the adsorption step. It may be an Activated Carbon-based or Zeolite-based having a ratio of 0.1 to 1.0.

The second PSA unit 200 is a device for separating and removing nitrogen from the source gas containing nitrogen from which ammonia has been removed in the first PSA unit 100, and is a source gas supply unit 201 containing nitrogen and hydrogen. ; Refined gas outlet 202 from which nitrogen is removed; and an exhaust gas discharge unit 301 containing the removed nitrogen as a main component. The purified gas outlet from which nitrogen is removed is a place where hydrogen from which all impurities are removed is discharged.

The exhaust gas discharge part is a place where nitrogen adsorbed in the second PSA part is discharged with exhaust gas containing hydrogen in the depressurization and regeneration step, and the exhaust gas is used as regeneration gas in the regeneration gas supply part of the first PSA part.

In addition, the second PSA unit consists of two or more containers filled with an adsorbent ('adsorbent B') for adsorbing nitrogen, and the adsorbent is adsorption time and desorption time of the adsorption step (total time of pressurization, decompression, and regeneration steps) It may be an Activated Carbon-based or Zeolite-based having a ratio of 0.1 to 1.0.

The control tank unit 300 may exist between the first PSA unit 100 and the second PSA unit 200, and may include a refinery gas controller 310 and a regeneration gas controller 320.

The detailed configuration of the control tank part 300 is shown in FIG. 6, and the refined gas control part 310 of the control tank part 300 uniformly regulates the pressure of the refined gas discharged from the first PSA part 100. The regeneration gas control unit 320 uniformly controls the pressure of the exhaust gas discharged from the second PSA unit 200 to supply the source gas of the second PSA unit 200 to the first PSA unit 100. supplied with regeneration gas.

Specifically, the refinery gas controller 310 includes one or more refinery gas buffer tanks 311; refinery gas control system 312; and a refined gas discharge unit 313, in which the refined gas buffer tank 311 includes the refined gas unit 102 of the first PSA unit 100 and the source gas unit 201 of the second PSA unit 200. ) are connected.

A refinery gas discharge unit 313 is connected to the upper end of the refinery gas buffer tank 311, and a refinery gas control system 312 consisting of a pressure transmitter and a control valve is installed in the refinery gas discharge unit 313. Depending on the pressure, the control valve can be automatically operated by receiving the output value of the pressure transmitter to maintain a constant pressure set in order to use the refined gas discharged from the first PSA unit 100 as a source gas for the second PSA unit 200. control so that

The regeneration gas controller 320 includes one or more regeneration gas buffer tanks 321; regeneration gas control system 322; and a regeneration gas discharge unit 323, and the regeneration gas buffer tank 321 includes the exhaust gas discharge unit 301 of the second PSA unit 200 and the regeneration gas supply unit of the first PSA unit 100 ( 302) are connected.

A regeneration gas discharge unit 323 is connected to the upper end of the regeneration gas buffer tank 321, and a regeneration gas control system 322 consisting of a pressure transmitter and a control valve is installed in the regeneration gas discharge unit 323, In order to use the exhaust gas discharged from the 2nd PSA unit 200 as the regeneration gas of the 1st PSA unit 100 by automatically operating the control valve by receiving the output value of the pressure transmitter according to the set pressure, the set pressure is maintained. control so that

7a and 7b show a method of operating the PSA system of FIG. 5 .

The operation of each of the first and second PSA units is cyclically operated in the order of pressurization, adsorption, decompression, and regeneration, which is indicated by a solid line in FIG. 7A.

The operation of the first and second PSA units may include an equalization step, if necessary, and when the equalization step is included, the operation of the first and second PSA units includes a pressurization step, an adsorption step, and an equalization step (co-current pressure reduction). , depressurization step, regeneration step, and equalization step (countercurrent pressurization) are cycled and operated in this order, which is indicated by a solid line in FIG. 7B.

In the method of operating the PSA system of the present invention, the refined gas of the first PSA unit 100 is discharged in the adsorption step of the first PSA unit 100 as shown by the dotted lines in FIGS. and injected as source gas in the pressurization step of the second PSA unit 200.

In addition, the exhaust gas of the second PSA unit 200 is discharged in the decompression step of the second PSA unit 200 and injected into the regeneration gas in the regeneration step of the first PSA unit 100 through the regeneration gas controller 320. used

Specifically, the operation method of the PSA system of the present invention according to FIG. 5

In the first PSA unit 100,

First, in the pressurization step, a high-pressure raw material gas including ammonia, nitrogen, and hydrogen is injected into the raw material gas part 101 to pressurize the container filled with the adsorbent A.

In the adsorption step, ammonia from the injected raw material gas is adsorbed to the adsorbent A of the pressurized container, and the ammonia-free gas is discharged through the refined gas unit 102.

In the decompression step, ammonia adsorbed in the adsorbent A filled in the container is desorbed and discharged to the exhaust gas unit 103 together with the remaining gas. In the decompression step, a vacuum pump can be used to increase the desorption efficiency.

In the regeneration step, regeneration gas is injected into the upper portion of the container to additionally desorb and remove ammonia that has not been desorbed, and discharged to the exhaust gas unit 103.

In the second PSA unit 200,

In the pressurization step, the ammonia is removed and the high-pressure gas containing nitrogen and hydrogen discharged to the refined gas part 102 of the first PSA part is injected from the raw material gas part 201 into the container filled with the adsorbent B, thereby cleaning the container. pressurize

In the adsorption step, nitrogen, which is an impurity, is adsorbed to the adsorbent B filled in the pressurized container, and the gas from which nitrogen is removed by the adsorption is discharged through the refining gas unit 202.

In the decompression step, the nitrogen adsorbed on the adsorbent B is desorbed and discharged to the exhaust gas unit 203 together with the remaining gas including some hydrogen remaining in the container. In the decompression step, a vacuum pump may be used to increase the desorption efficiency.

In the regeneration step, a portion of the refined gas is injected as regeneration gas into the upper part of the container to additionally desorb and remove undesorbed nitrogen and discharge it to the exhaust gas unit 301.

An equalization step may be included in the operating method of the PSA system including the first and second PSA as described above, and the equalization step is performed after the adsorption step and the regeneration step using a cocurrent pressure reduction method and a countercurrent pressure method, respectively. It can be (see Fig. 7b).

In addition, during operation of the first PSA unit and the second PSA unit as described above,

The gas discharged to the refined gas unit 102 in the adsorption step of the first PSA unit 100 is discharged at a non-constant pressure due to the circulation operation of the first PSA unit 100, but the control tank unit 300 It is injected into the refined gas buffer tank 311 configured in the refined gas unit 310 and is controlled at a constant pressure through the refined gas control system 312.

The gas controlled to a constant pressure is injected into the second PSA unit 200 through the source gas unit 201 in the pressurization step of the second PSA unit 200 .

In addition, the gas discharged to the exhaust gas unit 301 in the decompression step of the second PSA unit 200 is discharged at an irregular pressure due to the circulation operation of the second PSA unit 200, but the control tank unit 300 The regeneration gas is injected into the regeneration gas buffer tank 321 configured in the regeneration gas unit 320 and controlled at a constant pressure through the regeneration gas control system 322.

The exhaust gas of the second PSA unit controlled to the constant pressure is injected into the first PSA unit 100 through the regeneration gas unit 302 in the regeneration stage of the first PSA unit 100 .

The present invention may be better understood by the following examples, which are for purposes of illustration of the present invention and are not intended to limit the scope of protection defined by the appended claims.

In addition, the present invention is not limited to the following examples, and various modifications are possible without departing from the gist of the present invention claimed in the claims.

In order to calculate the 'main gas (hydrogen) recovery rate (%) according to the regeneration gas utilization method' of the present invention and the prior art, the apparatus shown in FIG. 8 was tested in Examples and Comparative Examples as follows.

<Main gas (hydrogen) recovery rate (%) according to regeneration gas utilization method>

Comparative Example 1

An adsorption tower filled with an adsorbent for adsorbing ammonia is provided, a regeneration gas supply unit and a refinery gas discharge unit are connected to the top of the adsorption tower together with valves A and B, respectively, and the source gas supply unit and the exhaust gas discharge unit are connected to valves C and valves D, respectively. It is connected to the bottom of the adsorption tower together with (see FIG. 8).

A gas not containing ammonia is injected by opening valve A, and the adsorption tower is pressurized (pressurization step). Thereafter, valve A is closed, source gas including hydrogen, ammonia, and nitrogen impurities, which is the main gas, is injected while maintaining high pressure for adsorption by opening valve C, and valve B is opened to discharge purified gas (adsorption step). At this time, the feed rate of the source gas was 17.15 LPM (hydrogen/nitrogen 97% (16.65 LPM), ammonia 3% (0.5 LPM)), the refinery gas discharged from the first PSA unit was 16.11 LPM, and the The concentration of ammonia was less than 0.1 ppm.

Thereafter, valve B and valve C were closed, and valve D was opened to lower the pressure of the adsorption tower so that desorption was smooth (depressurization step).

Thereafter, valve A was opened to inject some of 16.11 LPM of the purified gas discharged in the adsorption step into the adsorption tower (regeneration step). At this time, the flow rate of the refined gas used as the regeneration gas was 6.4 LPM.

After the regeneration, the valve D was closed, and the adsorption tower was pressurized again to a high pressure for adsorption to repeat the process.

The second PSA unit was operated using 9.71 LPM excluding 6.4 LPM of the 16.11 LPM, which is the refined gas of the first PSA unit. The recovery rate of the second PSA part is about 83%.

Meanwhile, the main gas recovery rate [%] is “first PSA unit recovery rate [%] × second PSA unit recovery rate [%]”, and the first PSA unit recovery rate [%] is “first PSA unit refined gas flow rate [%] LPM] ÷ flow rate [LPM] excluding ammonia in the raw material gas of the first PSA section”.

Therefore, the main gas recovery [%] of Comparative Example 1 using a part of the refined gas as the regeneration gas was about 48.4% (9.71 LPM ÷ 16.65 LPM = 58.32%, when the recovery rate of the second PSA part was 83%)

Comparative Example 2

Comparative Example 2 was performed in the same manner as Comparative Example 1 except that a separate inert gas was supplied from the outside as a regeneration gas in the regeneration step.

As described above, by using a separate inert gas instead of the refined gas of the first PSA unit as the regeneration gas, the second PSA unit was operated using the entire 16.11 LPM of the purified gas discharged from the first PSA unit. The recovery rate of the second PSA part is about 83%.

Therefore, the main gas recovery rate [%] of Comparative Example 2 using the inert gas supplied from the outside as the regeneration gas was about 80.3% (16.11 LPM ÷ 16.65 LPM = 96.76%, when the recovery rate of the second PSA unit is 83%)

Example 1

Example 1 was carried out in the same manner as Comparative Example 1 except that the exhaust gas of the second PSA was used as the regeneration gas in the regeneration step.

As described above, by using the exhaust gas of the second PSA as the regeneration gas, the second PSA unit was operated using the entire 16.11 LPM flow rate of the refined gas discharged from the first PSA unit. The recovery rate of the second PSA part is about 83%.

Therefore, the main gas recovery rate [%] of Comparative Example 2 using the inert gas supplied from the outside as the regeneration gas was about 80.3% (16.11 LPM ÷ 16.65 LPM = 96.76%, when the recovery rate of the second PSA unit is 83%)

Table 1 below shows the main gas (hydrogen) recovery rate (%) according to Comparative Examples 1 and 2 and Example 1.

Main gas (hydrogen) recovery rate [%] Comparative Example 1
(Some of the refined gas in the first PSA unit is used as regeneration gas) 48.40 Comparative Example 2
(separate inert gas is used as regeneration gas) 80.31 Example 1
(The exhaust gas of the 2nd PSA unit is used as regeneration gas) 80.31

As shown in Table 1, the main gas (hydrogen) recovery rate according to Example 2 of the present invention is 80.31%, which is almost twice as high as the main gas (hydrogen) recovery rate of 48.4% of Comparative Example 1, which is a prior art. .

On the other hand, Example 1 and Comparative Example 2 of the present invention have no difference in the recovery rate of the main gas (hydrogen) at 80.31%, but Comparative Example 2 requires a separate device to supply a separate inert gas as a regeneration gas from the outside. do.

Therefore, Example 1 of the present invention has an effect of improving the yield compared to Comparative Example 1, which is a prior art, and improving the economics of the process by simplifying the device compared to Comparative Example 2, which is another prior art.

From the results of these Examples and Comparative Examples, it can be seen that the PSA system of the present invention has an effect of improving the efficiency of obtaining the main gas by efficiently separating the main gas from the raw material gas containing impurities.

The scope of the present invention is not limited to the above-described embodiments, but may be implemented in various forms of embodiments within the scope of the appended claims. Anyone with ordinary knowledge in the art to which the invention pertains without departing from the subject matter of the invention claimed in the claims is considered to be within the scope of the claims of the present invention to various extents that can be modified.

100: first PSA part
200: second PSA part
300: control tank unit
101: first PSA source gas supply unit
102: first PSA refined gas discharge unit
103: first PSA exhaust gas discharge unit
201: second PSA source gas supply unit
202: second PSA refinery gas discharge unit
301: second PSA exhaust gas discharge unit
302: first PSA regeneration gas supply unit
310: Refining gas control unit
320: regeneration gas controller
311: refinery gas buffer tank
312: refinery gas control system
313: uniform pressure purification gas discharge unit
321: regeneration gas buffer tank
322: regeneration gas control system
323: uniform pressure regeneration gas discharge unit

Claims (16)

In the PSA system including the first PSA section 100 to the n-th PSA section 200 for removing n respective impurities from a source gas containing n impurities and a main gas,
The first PSA unit 100 to the nth PSA unit include a pressurization step, an adsorption step, a decompression step, and a regeneration step,
Characterized in that at least one of the exhaust gases discharged from the second PSA unit to the n-th PSA unit is used in the regeneration step of the first PSA unit 100 to the n−1 th PSA unit, including a main gas and impurities A PSA system for efficient separation of impurities from source gas (where n is an integer greater than or equal to 2). According to claim 1,
The first PSA unit includes a source gas supply unit containing all impurities; two or more adsorption towers filled with an adsorbent adsorbing the first impurity; a refined gas discharge unit from which the first impurities are removed; And an exhaust gas discharge unit containing the removed first impurities,
The n-th PSA unit includes the raw material gas supply unit excluding the n-1th impurity; two or more adsorption towers filled with an adsorbent adsorbing the nth impurity; a purified gas discharge unit from which nth impurities are removed; and an exhaust gas discharge unit including the removed n-th impurity.
Efficient separation of impurities from the main gas and source gas containing impurities, characterized in that impurities of the material with the strongest adsorption capacity are removed in the first PSA unit and impurities of the material with the weakest adsorption capacity are removed in the nth PSA unit. PSA system for According to claim 1 or 2,
The PSA system,
Further comprising 1 to n-1 control tank parts 300,
The control tank unit 300 is located between two PSA units selected from the first PSA unit 100 to the nth PSA unit 200,
Efficient separation of impurities from the source gas containing the main gas and impurities, characterized in that it is located between the two PSA units and acts to relieve pressure pulsation generated in the two PSA units PSA system for According to claim 3,
The control tank unit 300 includes a refinery gas control unit 310; And a regeneration gas controller 320; characterized in that it comprises a PSA system for efficient separation of impurities from the source gas containing the main gas and impurities According to claim 4,
The control tank unit 300 including the refined gas control unit 310 is characterized in that the two PSA units are located between the two PSA units that are continuous with each other, the n-1 th PSA unit and the n-th PSA unit , PSA system for efficient separation of impurities from source gas containing main gas and impurities According to claim 4,
The control tank unit 300 including the regeneration gas control unit 320 is characterized in that the two PSA units are located between two PSA units selected from the first PSA unit to the nth PSA unit, the main gas and a PSA system for efficient separation of impurities from raw material gas containing impurities. According to claim 4,
The refinery gas controller 310 includes one or more refinery gas buffer tanks 311; refinery gas control system 312; and a refined gas discharge unit 313;
To the refinery gas buffer tank 311, the refinery gas discharge unit 102 of the n−1th PSA unit 100 and the source gas supply unit 201 of the nth PSA unit 200 are connected, and one or more tanks are connected. including,
The refinery gas discharge unit 313 is connected to the top of the refinery gas buffer tank 311,
A refinery gas control system 312 is installed in the refinery gas discharge unit 313, and the pressure variation range of the refinery gas discharge unit 102 of the n−1 th PSA unit 100 injected into the refinery gas buffer tank 311 PSA system for efficient separation of impurities from the main gas and source gas containing impurities, characterized in that it acts to stably deliver to the source gas supply unit 201 of the n-th PSA unit 200 by reducing According to claim 7
The refinery gas control system 312 includes a pressure transmitter and a control valve, and the control valve operates by reading the output value of the pressure transmitter according to the set pressure, and accordingly, the refinery gas control system 312 automatically adjusts to the set pressure. PSA system for efficient separation of impurities from source gas containing main gas and impurities, characterized by controlling According to claim 4,
The regeneration gas controller 320 includes one or more regeneration gas buffer tanks 321; regeneration gas control system 322; and a regeneration gas discharge unit 323;
The regeneration gas buffer tank 321 is connected to the regeneration gas supply unit 302 of the n−1th PSA unit 100 and the exhaust gas discharge unit 301 of the nth PSA unit 200, and one or more tanks are connected. include,
The regeneration gas discharge unit 323 is connected to an upper end of the regeneration gas buffer tank 321, and a regeneration gas control system 322 is installed in the regeneration gas discharge unit 323 so that the regeneration gas buffer tank 321 ) to reduce the pressure fluctuation range of the exhaust gas discharge unit 301 of the n-th PSA unit 200 injected into the n-th PSA unit 200 and stably transfer it to the regeneration gas supply unit 302 of the n-1th PSA unit 100. PSA system for efficient separation of impurities from source gas containing main gas and impurities, According to claim 9
The regeneration gas control system 322 includes a pressure transmitter and a control valve, and the control valve operates by reading the output value of the pressure transmitter according to the set pressure, and accordingly, the regeneration gas control system 322 automatically adjusts the set pressure. PSA system for efficient separation of impurities from source gas containing main gas and impurities, characterized by controlling According to claim 1
The source gas is a PSA system for efficient separation of impurities from a source gas containing a main gas and impurities, characterized in that the source gas includes ammonia and nitrogen gas as impurities and hydrogen gas as a main gas. According to claim 2,
The source gas is a source gas containing ammonia and nitrogen gas as impurities and hydrogen gas as the main gas, and the nth PSA part is a second PSA part in which n is 2. PSA System for Efficient Separation of Impurities from Source Gases According to claim 12,
The adsorbent of the first PSA part is an activated carbon or zeolite system having a ratio of adsorption time and desorption time (total time of pressurization, decompression, and regeneration step) in the range of 0.1 to 1.0 in the adsorption step, characterized in that, the main gas and impurities PSA system for efficient separation of impurities from source gas containing According to claim 12,
The adsorbent of the second PSA unit is an activated carbon or zeolite system having a ratio of adsorption time and desorption time (total time of pressurization, decompression, and regeneration steps) in the range of 0.1 to 1.0 in the adsorption step, the main gas and impurities. PSA system for efficient separation of impurities from source gas containing In the operating method of a PSA system including a first PSA unit 100 to an n-th PSA unit 200 for removing n impurities from source gas containing n impurities and a main gas,
Refined gas of the n-1th PSA unit 100 is discharged in the adsorption step of the n-1th PSA unit 100, passed through the refined gas control unit 310, and converted to source gas in the pressurization step of the n-th PSA unit 200. being injected,
The exhaust gas of the n-th PSA unit 200 is discharged in the depressurization step of the n-th PSA unit 200 and injected as regeneration gas in the regeneration step of the n−1-th PSA unit 100 through the regeneration gas controller 320. A method of operating a PSA system for efficient separation of impurities from a main gas and source gas containing impurities (where n is an integer of 2 or more), characterized in that it comprises the step of being used. According to claim 15,
The raw material gas is a raw material gas containing ammonia and nitrogen gas as impurities and hydrogen gas as a main gas, and the n-1th PSA part and the nth PSA part are the first PSA part and the second PSA part, respectively (n is 2), a method of operating a PSA system for efficient separation of impurities from a source gas containing a main gas and impurities.

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