KR101600930B1 - Apparatus and method for recovery of retentate using gas separation membrane - Google Patents

Abstract

The recovery gas of the second gas separation membrane module, which recovers the recovery gas by using the first gas separation membrane module and the second gas separation membrane module and uses the permeation gas of the first gas separation membrane module as a feed gas, The target gas concentration contained in the recovery gas of the second gas separation membrane module is controlled so as to coincide with the target gas concentration contained in the feed gas of the first gas separation membrane module, The present invention relates to a target gas recovery apparatus and method using a gas separation membrane module capable of stably maintaining a target gas concentration contained in a gas. The target gas recovery apparatus using the gas separation membrane module according to the present invention includes a target gas to be recovered A supply gas supplying section for supplying the supplied supply gas, a gas mixing section for mixing the supply gas and the second recovering gas, A first gas separation membrane module for separating a mixed gas of a feed gas and a second recovered gas into a first permeation gas and a first recovered gas in accordance with a first SC value (? ₁ ) set; and a second gas separation membrane module 2 SC value ([theta] ₂ ), the second recovery gas is supplied to the gas mixing section, and the second recovery gas is supplied to the second recovery gas The second SC value [theta] ₂ is set so that the target gas concentration of the supply gas is equal to the target gas concentration of the supply gas.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus and a method for recovering a target gas using a gas separation membrane module,

The present invention relates to an apparatus and method for recovering a target gas using a gas separation membrane module, and more particularly, to a method and apparatus for recovering a recovered gas using a first gas separation membrane module and a second gas separation membrane module, In circulating the recovery gas of the second gas separation membrane module using the gas as the feed gas to the first gas separation membrane module, the target gas concentration contained in the recovery gas of the second gas separation membrane module is supplied to the feed gas To a target gas recovery apparatus and method using a gas separation membrane module capable of stably maintaining a target gas concentration contained in a recovery gas of a first gas separation membrane module.

SF ₆ is a typical electrical insulating material for electric power equipment and is used in the cleaning process of semiconductor wafers and LCD panels. Such SF ₆ has been the impact on global warming is known to be higher than carbon dioxide, more than 23,900 times, global warming is one of the largest six materials cited in the UNFCCC Parties Conference held in Kyoto in 1997 bar . Therefore, a process for SF ₆ is urgently required.

The processing method for the SF _6, there is a first method to decompose SF _6. Since SF ₆ is very stable, it requires a high energy such as plasma to decompose and has the disadvantage that by-products having high toxicity and corrosivity such as S ₂ F ₁₀ , SF ₄ , and HF are produced during the decomposition process. If such problems with the decomposition considering the continuous price rise of SF ₆ by effectively recovering SF ₆ is highly desirable in terms of reducing production costs to promote reuse.

Techniques for recovering SF ₆ is a technology for recovering only the SF ₆ in a mixed containing the SF ₆ gas, naengbeop seam in detail, there is a method such as a PSA (pressure swing adsorption) method, membrane separation process, the two of the gas separation membrane module Many studies have been conducted on the membrane separation method used. The membrane separation method is advantageous in that the structure of the apparatus is relatively simple and the recovery rate is comparatively excellent. An example of the membrane separation method is disclosed in Korean Patent No. 10-1249261.

In the membrane separation method, the waste gas is injected into the separation membrane module, and the separation membrane module proceeds by separating the injected waste gas into SF ₆ (recovery gas) and other gases (permeation gas). The treatment characteristics of the membrane separation method are determined by the selectivity and permeability of the membrane module. A high permeability of the membrane module is advantageous in that the treatment capacity is large. However, since the membrane having high permeability is low in selectivity, have.

As described above, the selectivity and the transparency of the separation membrane module have a trade-off. In the conventional case, a plurality of separation membrane modules are formed in a multi-stage configuration to enable a separation performance and a processing capacity of a certain level. However, when the plurality of separation membrane modules are repeatedly constructed in a multi-stage form, there is a disadvantage that the device configuration becomes complicated. In order to solve this problem, the present applicant has provided two separation membrane modules (first separation membrane module and second separation membrane module) through Korean Patent Application No. 2013-118138 and circulated the recovery gas and the permeation gas of the first separation membrane module And a technique for improving the recovery rate has been proposed.

Korean Patent No. 10-1249261

The recovery gas of the second gas separation membrane module, which recovers the recovery gas by using the first gas separation membrane module and the second gas separation membrane module and uses the permeation gas of the first gas separation membrane module as a feed gas, The target gas concentration contained in the recovery gas of the second gas separation membrane module is controlled so as to coincide with the target gas concentration contained in the feed gas of the first gas separation membrane module, And an object thereof is to provide a target gas recovery apparatus and method using a gas separation membrane module capable of stably maintaining a target gas concentration contained in a gas.

In addition, the present invention controls the SC (stage-cut) value of the first gas separation membrane module so as to correspond to the set target concentration, and controls the target gas concentration included in the recovery gas of the second gas separation membrane module, And the SC value of the second gas separation membrane module is controlled so that the target gas concentration contained in the supplied gas of the second gas separation membrane module is matched.

In addition, a design configuration for the optimal membrane area of the first gas separation membrane module and the second gas separation membrane module corresponding to the SC values of the first gas separation membrane module and the second gas separation membrane module is provided, It is another object of the present invention to provide an optimal pressure condition to be applied to the first gas separation membrane module and the second gas separation membrane module in response to a change in the flow rate of the gas.

According to an aspect of the present invention, there is provided a target gas recovery apparatus using a gas separation membrane module, including: a supply gas supply unit configured to supply a supply gas containing a target gas to be recovered; a gas supply unit configured to mix the supply gas and the second recovery gas; A first gas separation membrane module for separating a mixed gas of a feed gas and a second recovered gas into a first permeable gas and a first recovered gas in accordance with a first SC value (? ₁ ) And a second gas separation membrane module for separating the second gas separation membrane module into a second permeation gas and a second recovery gas in accordance with a second SC value (? ₂ ) set, wherein the second recovery gas is supplied to the gas mixing section, And a second SC value ([theta] ₂ ) is set so that the target gas concentration of the recovered gas matches the target gas concentration of the supplied gas.

The second SC value (? ₂ ) is calculated by the following equation (1) or (2).

(Equation 1)

(? ₂ is the second SC value, X _F is the target gas concentration in the feed gas,? ₁ is the selectivity of the first gas separation membrane module, and? ₂ is the selectivity of the second gas separation membrane module)

(Equation 2)

(θ ₂ is a second SC value, X _F is a target gas concentration in the feed gas, and α ₁ is a selectivity of the first gas separation membrane module and the second gas separation membrane module)

The first SC value (? ₁ ) is calculated by the following equation.

(expression)

(θ ₁ is selected in the first SC value, e ₁ is a first gas separation membrane module, the target gas concentration, α ₁ is a first gas separation membrane modules in the target concentration in Fig, X _F is the feed gas that is applied to a first gas separation membrane module Degree)

Wherein the first compression tank supplies a mixed gas of the feed gas and the second recovery gas to the first gas separation membrane module at a specific supply pressure, 1 permeable gas to the second gas separation membrane module at a specific supply pressure, and the supply pressure of the first compression tank and the supply pressure of the second compression tank are set to be the same. Further, the supply pressure P of the first compression tank and the supply pressure P of the second compression tank are calculated by the following equations.

(expression)

(P is the flow rate of the supply pressure, v is a real-time variation supply gas of the first compression tank and the second compression tank in which real-time setting, v _o is the flow rate of the first feed gas, P _o is the first compression tank and the second compression tank Of the initial supply pressure)

A supply pressure control unit is further provided for controlling the supply pressure of the first compression tank and the supply pressure of the second compression tank, and the supply pressure control unit checks the change in the flow rate of the supply gas, And the supply pressure of the second compression tank.

Set target enrichment first SC to control a first permeate gas flow rate and the first recovery gas flow rate of the gas separation membrane module to control the first first SC value of the gas separation membrane module (θ ₁₎ in accordance with (e ₁₎ regulator and, the first of the second gas separation membrane module to the second controlling a second SC value (θ ₂₎ of the gas separation membrane module so that the two coincides with the target gas concentration (X _F) in the target gas concentration in the recovered gas is supplied to gas 2 And a second SC regulator for regulating the permeate gas flow rate and the second recovered gas flow rate.

The membrane area of the first gas separation membrane module is set through the following equation.

(expression)

( ₁ is the membrane area of the first gas separation membrane module, v ₀ is the initial flow rate of the feed gas, _Po is the initial supply pressure of the first compression tank,? ₁ is the first SC value,? ₂ is the second SC value, P _{B, 1} is the permeability of the first recovered gas, α ₁ is the selectivity of the first gas separation membrane module, and X _F is the target gas concentration in the feed gas)

The membrane area of the second gas separation membrane module is set by the following Equation 1 or 2.

(Equation 1)

(A ₂ is the membrane area of the second gas separation membrane module, A ₁ is the membrane area of the first gas separation membrane module, θ ₂ is the second SC value, X _F is the target gas concentration in the feed gas _{, 2} is the permeability of the second recovered gas,? ₁ is the selectivity of the first gas separation membrane module, and? ₂ is the selectivity of the first gas separation membrane module.

(Equation 2)

(A ₂ is membrane area, A ₀ is the first membrane area of the gas separation membrane module, θ ₂ is the second SC value, X _F is the target gas concentration in the feed gas, α ₁ of the second gas separation membrane module is a first gas separation membrane Module and second gas separation membrane module)

The feed gas including the target base is a waste gas containing the fluoride gas or a waste gas including SF _6, wherein the target gas is SF ₆ gas or fluoride.

A target gas recovery method using a gas separation membrane module according to the present invention comprises a first gas separation membrane module and a second gas separation membrane module and separates the injected gas into a first permeation gas and a first recovery gas through a first gas separation membrane module And the second gas separation membrane module separates the first permeation gas of the first gas separation membrane module into a second permeation gas and a second recovery gas, and the first gas separation membrane module includes a feed gas and a second recovery Wherein the first gas separation membrane module separates the injected gas into a first permeable gas and a first recovered gas in accordance with a first SC value (? ₁ ), and the second gas- Is divided into a second permeable gas and a second recovered gas in accordance with a set second SC value (? ₂ ), and the second SC value? (?) Is adjusted so that the target gas concentration of the second recovered gas coincides with the target gas concentration of the feed gas. ₂₎ wherein the lead set The.

The target gas recovery apparatus and method using the gas separation membrane module according to the present invention have the following effects.

The first SC value corresponding to the target concentration degree is set and the second SC value is set so that the target gas concentration of the second recovered gas coincides with the target gas concentration of the feed gas, The concentration can be kept constant, and the reliability of the membrane separation process can be improved.

In addition, it is also possible to optimize the membrane area of the first and second gas separation membrane modules and selectively control the supply pressures of the first and second gas separation membrane modules in accordance with the change in flow rate of the feed gas, Can be maintained stably and constantly.

1 is a configuration diagram of a target gas recovery device using a gas separation membrane module according to an embodiment of the present invention.

The present invention relates to a technique for recovering a target gas from an injection gas using a gas separation membrane module.

In the gas separation membrane module, a highly permeable gas having a relatively small molecular size (hereinafter referred to as a "permeable gas") permeates through pores and a low permeable gas having a relatively large molecular size (hereinafter referred to as a "recovered gas" It is a device which remains in the gas separation membrane module and is recovered. When the injection gas is supplied to the gas separation membrane module, it is separated into the permeation gas and the recovery gas by the gas separation membrane module.

The target gas is the gas to be finally recovered through the gas separation membrane module, for example, SF ₆ contained in the waste gas. The target gas SF ₆ is contained in the feed gas (waste gas) at a predetermined concentration. When the feed gas is separated into the permeable gas and the recovered gas by the gas separation membrane module, a considerable number of target gases are contained in the recovered gas, Includes a small amount of target gas. The reason why the target gas having a relatively large molecular size is contained in the permeation gas is that the target gas having a relatively large molecular size permeates the pores of the gas separation membrane module because the pore size is not constant Because. In other words, it can be explained that the permeability of the target gas in the permeability of the gas permeating the pores of the gas separator module is smaller than the permeability of the other gas in the waste gas, so that the possibility of remaining in the gas separator module is high. Thus, the target gas concentration in the recovered gas can be expressed as being relatively larger than the target gas concentration in the permeated gas.

The present invention provides a technique for maintaining the target gas concentration in the recovery gas at a constant level in the recovery of the recovery gas.

Generally, the permeate gas and the recovered gas are separated through the gas separation membrane module, and the flow rate of the permeate gas and the flow rate of the recovered gas are controlled through a set SC (Stage-cut) value. If one gas separation membrane module is used and the concentration of the target gas contained in the injected gas supplied to the gas separation membrane module is constant, the target gas concentration in the recovery gas can be kept constant through the SC value control. However, when a plurality of gas separation membrane modules are used and the target gas concentration in the gas to be supplied to the gas separation membrane module is fluid, various variables must be considered in controlling the SC value.

The first gas separation membrane module and the second gas separation membrane module are separated by the first gas separation membrane module and the first gas separation membrane module is divided into the first gas separation membrane module and the first gas separation membrane module, Separating the first permeable gas of the separator module into a second permeable gas and a second recoverable gas as an injector body and supplying a second recovered gas of the second gas separation membrane module to a part of the injected gas of the first gas separation membrane module . The first gas separation membrane module is supplied with the second recovery gas of the second gas separation membrane module in addition to the supply gas (waste gas) supplied from the supply gas supply part.

With this configuration, the target gas concentration in the first recovered gas is specified, the first SC value of the first gas separation membrane module is controlled to correspond to the target gas concentration in the first recovered gas, and the target gas concentration The second SC value of the second separation membrane module is controlled so that the second SC value is equal to the target gas concentration in the feed gas. Whereby the target gas concentration in the first recovered gas can be kept constant. When the target gas concentration in the second recovered gas and the target gas concentration in the supplied gas are different from each other, the concentration of the target gas contained in the injected gas (the supplied gas + the second recovered gas) supplied to the first gasketing membrane module is changed Even if the first SC value of the first gas separation membrane module is specified, the target gas concentration in the first recovery gas can not be maintained constant.

Further, the present invention provides an additional structure for maintaining the target gas concentration in the first recovered gas at a constant level, wherein the first gas separation membrane module satisfies the first SC value and the second SC value, And presents the optimal pressure conditions to be applied to the first gasketing membrane module and the second gasketing membrane module in response to the flow rate change of the supply gas.

Hereinafter, a target gas recovery apparatus and method using a gas separation membrane module according to an embodiment of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, a target gas recovery apparatus using a gas separation membrane module according to an embodiment of the present invention includes a supply gas supply unit 110, a gas mixing unit 120, a first compression tank 130, Module 140, a first SC regulator 150, a second compression tank 160, a second gasket separator module 170, and a second SC regulator 180.

The supply gas supply unit 110 serves to supply a supply gas including a target gas. Wherein the target gas comprises a first and a gas to be recovered through the gas separation membrane module 140 and the second gas separation membrane module 170, the feeder body containing the target gas is waste gas or NF containing SF _{6 3,} CF _4, etc. , And SF ₆ , NF ₃ , CF _4, and the like correspond to the target gas. A target gas is mixed in the supply gas at a predetermined concentration. In the following explanation it will be described on the basis of the waste gas including SF _6.

The gas mixing section 120 serves to mix the supply gas supplied from the supply gas mixing section with the second recovery gas supplied from the second gas separation membrane module 170, (Injection gas) of the supply gas and the second recovery gas to a predetermined pressure and supplies the compressed gas to the first gas separation membrane module 140. The supply pressure to the first gasketing membrane module 140 for the mixed gas of the feed gas and the second recovered gas may vary according to the change in the flow rate of the feed gas, which will be described later.

The first gas separation membrane module 140 separates the injected gas into a first permeable gas and a first recovered gas. In this case, the injected gas means a mixed gas of a feed gas or a feed gas and a second recovered gas, and the first gas separation membrane module 140 converts the injected gas into a recovered gas and a permeable gas Separate.

Wherein the relative of O _2, N _2, CO _2, etc. one gas separation membrane module 140 (and the second gas separation membrane module 170) is a membrane assembly of a hollow fiber form pores formed on its surface, except for the SF ₆ gas The gas having a small molecular size quickly passes through the pores of the separation membrane and is discharged. The relatively large molecular size SF ₆ is recovered at one end of the separation membrane without permeating the pores. The gas to be discharged through the pores of the separation membrane is a permeation gas, and the gas recovered from one end of the separation membrane is a recovery gas. At this time, relative to the molecular size of a small gas (O _2, N _2, CO _2, etc.) as well as relative to the molecular size is larger SF ₆ gas is also there is discharged by passing through the pores of the membrane, the permeability of the SF ₆ gas O _2, N ₂ , and CO _2. Therefore, SF ₆ gas can be recovered as a recovered gas, and substantially gases such as O ₂ , N ₂ and CO ₂ are highly permeable gases and SF ₆ gas is a low permeable gas .

The first SC (stage-cut) regulator 150 controls the first SC (stage-cut) value? ₁ of the first gasket separation membrane module 140 according to the set target concentration e, And controls the permeate flow rate and the recovered gas flow rate of the gas separation membrane module 140. The SC value means the ratio of the flow rate of the permeated gas to the flow rate of the injected gas as shown in Equation 2 below. For example, if the SC value is 0.95, then the permeate flow rate versus the inlet gas flow rate is 95% and the recovered gas flow rate is 5%, which means that 5% of the total injected gas is recovered (see Equations 1 and 2) .

(Formula 1) Injected gas flow rate (F _f ) = permeate gas flow rate (F _p ) + recovered gas flow rate (F _r )

(Equation 2) SC = permeable gas flow rate (F _p ) / injected gas flow rate (F _f )

In the present invention, the first SC value (? ₁ ) is controlled according to the set target degree of enrichment. The target concentration (e) means the ratio of the target gas concentration (X _R ) in the first recovered gas to the target gas concentration (X _F ) in the supplied gas (see Equation 3). The target concentration (e) can be calculated by setting the target gas concentration (X _R ) in the first recovered gas in a state where the target gas concentration (X _F ) in the supplied gas is determined. The target gas concentration X _{R in} the first recovered gas may be the concentration of the target gas ultimately recovered through the apparatus of the present invention and may be input to the first SC regulator 150 through a separate input means .

(Equation 3) Target concentration (e ₁ ) = X _R / X _F

(e ₁ is the target concentration of the first gas separation membrane module, X _F is the target gas concentration in the feed gas, and X _R is the target gas concentration in the first recovery gas)

When the target concentration (e ₁ ) is set, the first SC value (? ₁ ) is calculated by the following equation (4). In order to calculate the first SC value (? ₁ ), the target gas concentration (X _F ) in the supplied gas and the selectivity? ₁ of the first gas separation membrane module 140 are required in addition to the target concentration (e ₁ ) .

In the above description, the injection gas injected into the first gas separation membrane module 140 includes the second recovery gas of the second gas separation membrane module 170 in addition to the feed gas. Therefore, the target gas concentration information in the second recovery gas must be reflected in addition to the target gas concentration (X _F ) in the feed gas when calculating the first SC value (? ₁ ). In the present invention, the target gas concentration in the second recovery gas controlled to match the target gas concentration (X _F) in the feed gas and to, any one of claim 1 SC value (θ ₁₎ the target gas concentration in the target gas concentration (X _F) or the second number of the gas in the feed gas to the calculation formula of It is possible to calculate the first SC value (? ₁ ) even if only one piece of information is applied. The reason why the target gas concentration in the second recovered gas is controlled to coincide with the target gas concentration (X _F ) in the supplied gas is to maintain the target gas concentration in the first recovered gas at a constant level, which will be described later do.

The selectivity α ₁ of the first gas separation membrane module 140 means the ratio of the permeability Q _air of the permeable gas to the permeability Q _B of the recovered gas. And the selectivity of the second gas separation membrane module 170 may be the same or different.

(Equation 4)

(θ ₁ is selected in the first SC value, e ₁ is a first gas separation membrane module, the target gas concentration, α ₁ is a first gas separation membrane modules in the target concentration in Fig, X _F is the feed gas that is applied to a first gas separation membrane module Degree)

(Expression 5)? ₁ = P _A / P _B

(? ₁ is selectivity of the first gas separation membrane module, P _B is the permeability of the recovered gas, and P _A is the permeability of the permeable gas)

The second compression tank 160 compresses the first permeable gas of the first gas separation membrane module 140 to a predetermined pressure and supplies the compressed gas to the second gas separation membrane module 170.

The supply gas supplied from the supply gas supply unit 110 is set to be supplied at a constant flow rate but has a characteristic that changes in real time due to various factors such as equipment condition, temperature, and pressure on the supply gas supply unit 110 side, The flow rates of the permeable gas and the recovered gas separated by the first gas separation membrane module 140 and the second gas separation membrane module 170 are influenced even if the SC value is specified. That is, if the flow rate of the feed gas is changed, the flow rate of the permeated gas and the recovered gas can not be maintained constant.

It is necessary to vary the supply pressure of the injection gas injected into the first gas separation membrane module 140 and the second gas separation membrane module 170 in accordance with the change in the flow rate of the supply gas . Specifically, the supply pressure P of the first compression tank 130 and the second compression tank 160 can be set as shown in Equation 6 below. That is, when a change occurs in the flow rate of the supply gas, the flow rate change ratio (v / v _o ) of the supply gas is multiplied by the initial supply pressure (P _o ) Set the supply pressure. At this time, the supply pressure of the first compression tank 130 and the supply pressure of the second compression tank 160 are set to be the same.

A supply pressure control unit may be further provided to control the supply pressure of the first compression tank 130 and the supply pressure of the second compression tank 160 according to a change in the flow rate of the supply gas, The supply pressure of the first compression tank 130 and the supply pressure of the second compression tank 160 can be set using the equation 6 by checking the flow rate change.

(Equation 6)

(P is the flow rate of the supply pressure, v is a real-time variation supply gas of the first compression tank and the second compression tank in which real-time setting, v _o is the flow rate of the first feed gas, P _o is the first compression tank and the second compression tank Of the initial supply pressure)

The second gas separation membrane module 170 separates the first permeable gas of the first gas separation membrane module 140 into a second permeable gas and a second recoverable gas as an injector.

The second SC regulator 180 controls the second gas separator module 170 such that the target gas concentration Y _R in the second recovery gas of the second gasket separation membrane module 170 matches the target gas concentration X _F in the feed gas. The second SC value [theta] < ₂ >

A second calculator for calculating the SC value (θ ₂₎ expression by default, the 1 SC value the same as the calculation equation (Equation 4) (θ _1), the 1 SC value (θ ₁₎ is also the target concentration of the calculation formula (e ₁ ) instead of the target concentration (e ₂ ) of the second gas separation membrane module 170.

The target concentration of the second gasket separator module 170 and the target concentration e ₁ of the second gasket separator module 170 are equal to the target concentration of the first gasket module 140, Is set to the ratio of the target gas concentration (Y _R ) in the second recovery gas to the target gas concentration (Y _R ) in the second recovery gas. Further, as the second number of the target gas density (Y _R) is set to match the target gas concentration (X _F) in the feed gas in the gas in the present invention, the target concentration of the second gas separation membrane module 170. FIG. (E ₁ ) Can be set to the ratio of the target gas concentration (X _F ) in the supply gas to the target gas concentration (Y) in the first transmission gas as shown in the following equation (7).

(Equation 7) e ₂ = Y _R / Y = X _F / Y

(where e ₁ is the target concentration of the second gas separation membrane module, Y is the target gas concentration in the first permeable gas, Y _R is the target gas concentration in the second recovered gas, and X _F is the target gas concentration in the feed gas)

Thus, the first even target concentration of Equation SC value (e ₁₎ instead of the target in the second gas separation membrane is applied to the target concentration of the module 170. Fig. (E ₂₎ is replaced, the first feed gas of Equation SC value The calculation formula of the second SC value (? ₂ ) to which the target gas concentration (Y) in the first transparent gas is applied instead of the gas concentration (X _F ) is shown in the following equation (8). Then, the calculation formula of the second SC value (? ₂ ) through the derivation process of Equation (9) is finally expressed as Equation (10). When the selectivities of the first gas separation membrane module 140 and the second gas separation membrane module 170 are the same, the second SC value (? ₂ ) calculation expression is expressed by Expression 11.

(Expression 8)

(θ ₂ is the second SC value, Y1 is selected in the target gas concentrations, α ₂ is the second gas separation membrane modules in the target gas concentration in the first permeate gas, X _F is the feed gas also)

(Equation 9)

(Equation 10)

(? ₂ is the second SC value, X _F is the target gas concentration in the feed gas,? ₁ is the selectivity of the first gas separation membrane module, and? ₂ is the selectivity of the second gas separation membrane module)

(Expression 11)

(θ ₂ is a second SC value, X _F is a target gas concentration in the feed gas, and α ₁ is a selectivity of the first gas separation membrane module and the second gas separation membrane module)

It is possible to calculate the second SC value satisfying that the target gas concentration of the second recovered gas coincides with the target gas concentration in the feed gas through the above-described second SC value (? ₂ ) calculating formula. The second SC regulator 180 may calculate the second SC value (? ₂ ) using the second SC value calculation equation under the condition that the target gas concentration in the second recovery gas and the target gas concentration in the feed gas are the same And the calculated second SC value [theta] ₂ is applied to the operation of the second gas separation membrane module 170. [

The configuration of the target gas recovery apparatus using the gas separation membrane module according to one embodiment of the present invention has been described above. Claim be kept constant, as the target gas concentration set the target gas concentration in the first number of gas through the above-described configuration, the first stable maintenance of the number of target gas concentration in the gas is a first gas which also correspond to (e ₁₎ target concentration a second SC value of the separation membrane module (140) of claim 1 SC value (θ ₁₎ control and a second gas separation membrane module (170) to match the target gas concentration and supply the target gas concentration in the gas of the recovery gas (θ ₂ ). ≪ / RTI >

On the other hand, the first gas separation membrane module 140 and the second gas separation membrane module 170 need to be designed to have an optimal membrane area with an additional configuration for keeping the target gas concentration of the first recovered gas constant. . For this, the membrane area of the first gas separation membrane module 140 may be designed as shown in Equation 12 below, and the membrane area of the second gas separation membrane module 170 may be designed as shown in Equation 13 below. If the selectivities of the first gasket separator module 140 and the second gasket separator module 170 are the same, the membrane area of the second gasket separator module 170 can be designed as shown in equation (14). In addition, when the second recovered gas is not circulated to the first gas separation membrane module 140, the membrane area of the first gas separation membrane module 140 can be designed as shown in equation (15).

(Expression 12)

( ₁ is the membrane area of the first gas separation membrane module, v ₀ is the initial flow rate of the feed gas, _Po is the initial supply pressure of the first compression tank,? ₁ is the first SC value,? ₂ is the second SC value, P _{B, 1} is the permeability of the first recovered gas, α ₁ is the selectivity of the first gas separation membrane module, and X _F is the target gas concentration in the feed gas)

(Expression 13)

(A ₂ is the membrane area of the second gas separation membrane module, A ₁ is the membrane area of the first gas separation membrane module, θ ₂ is the second SC value, X _F is the target gas concentration in the feed gas _{, 2} is the permeability of the second recovered gas,? ₁ is the selectivity of the first gas separation membrane module, and? ₂ is the selectivity of the first gas separation membrane module.

(Equation 14)

(A ₂ is membrane area, A ₀ is the first membrane area of the gas separation membrane module, θ ₂ is the second SC value, X _F is the target gas concentration in the feed gas, α ₁ of the second gas separation membrane module is a first gas separation membrane Module and second gas separation membrane module)

(Expression 15)

(A ₁ is the first membrane area of the gas separation membrane module, θ is SC value, v ₀ is the initial flow rate of feed gas, X _F is a target gas concentration, P _A is transmitted through transmission of the gas in the feed gas, P _B is recovered gas , P _o is the supply pressure)

Next, a target gas recovery method using a gas separation membrane module according to an embodiment of the present invention will be described. The target gas recovery method using the gas separation membrane module according to an embodiment of the present invention proceeds based on the apparatus configuration of FIG. 1, that is, the target gas recovery apparatus using the gas separation membrane module according to an embodiment of the present invention.

First, the target gas concentration X _R of the first recovered gas is set, and the target concentration (e) is set accordingly. The target concentration (e) is the ratio of the target gas concentration (X _R ) in the first recovered gas to the target gas concentration (X _F ) in the supplied gas, and is calculated through Equation (3).

(Equation 3) Target concentration (e ₁ ) = X _R / X _F

(e ₁ is the target concentration of the first gas separation membrane module, X _F is the target gas concentration in the feed gas, and X _R is the target gas concentration in the recovery gas)

In the target enrichment (e ₁₎ calculating a state, the objective is also concentrated (e ₁₎ is set to claim 1 SC value (θ ₁₎ that satisfies. Claim 1 SC value (θ ₁₎ is calculated by the formula 4 below, wherein the 1 SC value (θ ₁₎ to FIG. (E ₁₎ in addition to supply the target gas concentration (X _F) in the gas target concentration of the calculation of, The selectivity alpha ₁ of the first gasketing membrane module 140 is required.

(Equation 4)

(θ ₁ is selected in the first SC value, e ₁ is a first gas separation membrane module, the target gas concentration, α ₁ is a first gas separation membrane modules in the target concentration in Fig, X _F is the feed gas that is applied to a first gas separation membrane module Degree)

The first set also claim 2 SC value (θ ₂₎ with the SC value (θ _1). The second SC value (? ₂ ) is calculated through Equation (10) under the condition that the target gas concentration of the second recovered gas is equal to the target gas concentration (X _F ) of the supplied gas. At this time, if the selectivities of the first gas separation membrane module 140 and the second gas separation membrane module 170 are the same, the second SC value? ₂ is calculated through Expression 11. In addition to setting the first SC value (? ₁ ) and the second SC value (? ₂ ), in order to maintain the target gas concentration in the first recovered gas constant, the first gas separator module (140) The optimum membrane area of the separation membrane module 170 may be designed by using the above-mentioned Expressions 12 to 15, respectively.

(Equation 10)

(? ₂ is the second SC value, X _F is the target gas concentration in the feed gas,? ₁ is the selectivity of the first gas separation membrane module, and? ₂ is the selectivity of the second gas separation membrane module)

(Expression 11)

(θ ₂ is a second SC value, X _F is a target gas concentration in the feed gas, and α ₁ is a selectivity of the first gas separation membrane module and the second gas separation membrane module)

In this way, the target enrichment (e), the first SC value (θ ₁₎ and the second set the SC value (θ ₂₎ state, a first gas separation membrane module 140 and the second gas separation membrane module (170) The recovery process of the target gas used proceeds.

Specifically, a feed gas containing a target gas, for example, a feed gas containing SF ₆ is supplied from the feed gas feeder 110 to the gas mixer 120, and the gas mixer 120 feeds the feed gas and the second The second recovered gas recovered by the gas separator module 170 is mixed and the mixed gas of the feed gas and the second recovered gas is supplied to the first compression tank 130. Only the supply gas is supplied to the first compression tank 130 since the second recovery gas of the second gas separation membrane module 170 is not supplied to the gas mixing unit 120 during the initial operation.

The first compression tank 130 compresses the mixed gas to a predetermined pressure and injects the mixed gas into the first gas separation membrane module 140. It is necessary to vary the supply pressure of the injection gas injected into the first gasketing membrane module 140 in accordance with the change in the flow rate of the supply gas in order to cope with the change in the flow rate of the supply gas. (P) is set as shown in Equation (6) below. The supply pressure of the second compression tank 160, which will be described later, is also set equal to the supply pressure of the first compression tank 130.

(Equation 6)

(P is the flow rate of the supply pressure, v is a real-time variation supply gas of the first compression tank and the second compression tank in which real-time setting, v _o is the flow rate of the first feed gas, P _o is the first compression tank and the second compression tank Of the initial supply pressure)

The injected gas injected into the first gas separation membrane module 140 at a constant supply pressure P is separated into a first permeable gas and a first recovered gas by the first gas separation membrane module 140. At this time, the flow rate of the first permeable gas and the flow rate of the first recovered gas are determined by the set first SC value (? ₁ ). The first recovered gas is collected at one end of the first gas separation membrane module 140 and stored in a separate recovered gas storage tank.

The first permeable gas separated by the first gas separation membrane module 140 is supplied to the second compression tank 160 and the second compression tank 160 is supplied with the same supply pressure as the supply pressure of the first compression tank 130 And the first permeable gas is injected into the second gas separation membrane module 170 under pressure.

The second gas separation membrane module 170 separates the injected first transparent gas into a second transparent gas and a second recovered gas. At this time, the flow rate of the second permeable gas and the flow rate of the second recovered gas are determined by the set second SC value (? ₂ ).

The second recovery gas separated by the second gas separation membrane module 170 is supplied to the gas mixing unit 120 and the second recovery gas and the supply gas are mixed in the gas mixing unit 120. Then, the mixed gas of the second recovered gas and the supplied gas is supplied to the first gas separation membrane module 140 via the first compression tank 130, and the target gas recovery process is repeatedly performed as described above.

In the second recovery gas supplied to the gas mixing portion 120, the target gas concentration of the second recovery gas is equal to the target gas concentration (X _F ) of the supply gas, and the first gas separation membrane module The target gas concentration of the injected gas is kept constant and the target gas concentration of the first recovered gas recovered by the first gas separation membrane module 140 can be maintained stably and constantly.

The target gas recovery apparatus and method using the gas separation membrane module according to one embodiment of the present invention have been described above. Next, experimental results on specific setting of the target concentration (e), the first SC value (? ₁ ), and the second SC value (? ₂ ) will be described.

SF ₆ has a waste gas mixture to 2vol% to the feed gas, and the first transmission rate of the gas separation membrane module and the second gas separation membrane module (P _A, P _B) and selectivity characteristics, the first gas separation membrane module and the second gas separation membrane supply pressure of the injection gas to be injected into the module (P _o) conditions, the supply flow rate of the gas (v _o) is set in a given state, as shown in Table 1 below, the target gas concentration in the first recovery gas as 30%, corresponding The first SC value (? ₁ ) and the second SC value (? ₂ ) were calculated.

The first SC value (? ₁ ) was 0.937 and the second SC value (? ₂ ) was 0.951 in order to satisfy the experimental condition of Table 1 and the condition that the target gas concentration of the first recovered gas was 30%. The optimum membrane areas of the first gas separation membrane module and the second gas separation membrane module were 4.445 m ² , 4.152m ² . As a result of applying the first SC value (? ₁ ), the second SC value (? ₂ ), and the membrane area design, it was confirmed that the target gas concentration of the first recovered gas was maintained close to 30%.

Experimental conditions division Condition Transmission gas permeability (P _A ) 5 GPU The recovered gas permeability (P _A ) 0.25 GPU Selectivity (? _{A / B} ) 20 Supply pressure (P _o ) 0.5 MPa The feed gas flow rate (v _o ) 5 LPM The target gas concentration (X _F ) 0.02

110: supply gas supply unit 120: gas mixing unit
130: first compression tank 140: first gas separation membrane module
150: first SC regulator 160: second compression tank
170: Second gas separation membrane module 180: Second SC regulator

Claims (20)

A supply gas supply unit for supplying a supply gas containing a target gas to be recovered;
A gas mixing section for mixing the feed gas and the second recovered gas;
A first gas separation membrane module for separating a mixed gas of a feed gas and a second recovered gas into a first permeable gas and a first recovered gas in accordance with a first SC value (? ₁ ) set; And
And a second gas separation membrane module for separating the first transparent gas into a second transparent gas and a second recover gas in accordance with a second SC value (&thetas; ₂ )
The second recovery gas is supplied to the gas mixing portion,
The second SC value ([theta] ₂ ) is set such that the target gas concentration of the second recovered gas matches the target gas concentration of the feed gas,
Wherein the first SC value (? ₁ ) is calculated through the following equation.
(expression)

(θ ₁ is selected in the first SC value, e ₁ is a first gas separation membrane module, the target gas concentration, α ₁ is a first gas separation membrane modules in the target concentration in Fig, X _F is the feed gas that is applied to a first gas separation membrane module Degree)
2. The gas recovery system of claim 1, wherein the second SC value (? ₂ ) is calculated by the following equation.
(expression)

(? ₂ is the second SC value, X _F is the target gas concentration in the feed gas,? ₁ is the selectivity of the first gas separation membrane module, and? ₂ is the selectivity of the second gas separation membrane module)
2. The gas recovery system of claim 1, wherein the second SC value (? ₂ ) is calculated by the following equation.
(expression)

(θ ₂ is a second SC value, X _F is a target gas concentration in the feed gas, and α ₁ is a selectivity of the first gas separation membrane module and the second gas separation membrane module)
delete [2] The apparatus of claim 1, further comprising a first compression tank and a second compression tank,
The first compression tank supplies the mixed gas of the supply gas and the second recovery gas to the first gas separation membrane module at a specific supply pressure,
The second compression tank supplies the first permeable gas to the second gas separation membrane module at a specific supply pressure,
Wherein the supply pressure of the first compression tank and the supply pressure of the second compression tank are set to be equal to each other.
6. The gas recovery system as claimed in claim 5, wherein the supply pressure (P) of the first compression tank and the supply pressure (P) of the second compression tank are calculated by the following equations.
(expression)

(P is the flow rate of the supply pressure, v is a real-time variation supply gas of the first compression tank and the second compression tank in which real-time setting, v _o is the flow rate of the first feed gas, P _o is the first compression tank and the second compression tank Of the initial supply pressure)
The apparatus according to claim 6, further comprising a supply pressure control unit for controlling a supply pressure of the first compression tank and a supply pressure of the second compression tank,
Wherein the supply pressure control unit sets the supply pressure of the first compression tank and the supply pressure of the second compression tank by using the equation described in claim 5 by checking the change in flow rate of the supply gas, Recovery device.
The method as claimed in claim 1, wherein the first SC value (? ₁ ) of the first gas separation membrane module is controlled according to the set target concentration (e ₁ ) to calculate the first permeate flow rate of the first gas separation membrane module and the first recovered gas flow rate A first SC regulator for regulating the output of the first SC regulator,
The second SC value (? ₂ ) of the second gas separation membrane module is controlled so that the target gas concentration of the second recovered gas coincides with the target gas concentration (X _F ) in the feed gas, And a second SC regulator for regulating a flow rate of the second recovered gas.
The gas recovery system as claimed in claim 1, wherein the membrane area of the first gas separation membrane module is set through the following equation.
(expression)

( ₁ is the membrane area of the first gas separation membrane module, v ₀ is the initial flow rate of the feed gas, _Po is the initial supply pressure of the first compression tank,? ₁ is the first SC value,? ₂ is the second SC value, P _{B, 1} is the permeability of the first recovered gas, α ₁ is the selectivity of the first gas separation membrane module, and X _F is the target gas concentration in the feed gas)
The gas recovery system as claimed in claim 1, wherein the membrane area of the second gas separation membrane module is set through the following equation.
(expression)

(A ₂ is the membrane area of the second gas separation membrane module, A ₁ is the membrane area of the first gas separation membrane module, θ ₂ is the second SC value, X _F is the target gas concentration in the feed gas _{, 2} is the permeability of the second recovered gas,? ₁ is the selectivity of the first gas separation membrane module, and? ₂ is the selectivity of the first gas separation membrane module.
The gas recovery system as claimed in claim 1, wherein the membrane area of the second gas separation membrane module is set through the following equation.
(expression)

(A ₂ is membrane area, A ₀ is the first membrane area of the gas separation membrane module, θ ₂ is the second SC value, X _F is the target gas concentration in the feed gas, α ₁ of the second gas separation membrane module is a first gas separation membrane Module and second gas separation membrane module)
The method of claim 1 wherein the feed gas including the target base is a waste gas containing waste gas or fluoride gas with the SF _6, wherein the target gas is a target using a gas separation membrane module, characterized in that SF ₆ or fluoride gas Gas recovery device.
Wherein the first gas separation membrane module and the second gas separation membrane module are constructed so that the first gas separation membrane module is divided into a first permeation gas and a first recovery gas through the first gas separation membrane module, The first permeable gas is separated into a second permeable gas and a second recovered gas, the first gas separation membrane module is supplied with the feed gas and the second recovered gas of the second gas separation membrane module,
The first gas separation membrane module separates the injected gas into a first permeable gas and a first recovered gas in accordance with a first SC value (? ₁ )
The second gas separation membrane module separates the first transparent gas into a second transparent gas and a second gas according to a second SC value (&thetas; ₂ )
The second SC value ([theta] ₂ ) is set such that the target gas concentration of the second recovered gas matches the target gas concentration of the feed gas,
Wherein the first SC value (? ₁ ) is calculated through the following equation.
(expression)

(θ ₁ is selected in the first SC value, e ₁ is a first gas separation membrane module, the target gas concentration, α ₁ is a first gas separation membrane modules in the target concentration in Fig, X _F is the feed gas that is applied to a first gas separation membrane module Degree)
14. The method as claimed in claim 13, wherein the second SC value (? ₂ ) is calculated through the following equation.
(expression)

(? ₂ is the second SC value, X _F is the target gas concentration in the feed gas,? ₁ is the selectivity of the first gas separation membrane module, and? ₂ is the selectivity of the second gas separation membrane module)
14. The method as claimed in claim 13, wherein the second SC value (? ₂ ) is calculated through the following equation.
(expression)

(θ ₂ is a second SC value, X _F is a target gas concentration in the feed gas, and α ₁ is a selectivity of the first gas separation membrane module and the second gas separation membrane module)
delete 14. The apparatus of claim 13, further comprising a first compression tank and a second compression tank,
The first compression tank supplies the mixed gas of the supply gas and the second recovery gas to the first gas separation membrane module at a specific supply pressure,
The second compression tank supplies the first permeable gas to the second gas separation membrane module at a specific supply pressure,
The supply pressure of the first compression tank and the supply pressure of the second compression tank are set to be equal to each other and the supply pressure P of the first compression tank and the supply pressure P of the second compression tank are set by the following equations And the target gas is recovered by the gas separation membrane module.
(expression)

(P is the flow rate of the supply pressure, v is a real-time variation supply gas of the first compression tank and the second compression tank in which real-time setting, v _o is the flow rate of the first feed gas, P _o is the first compression tank and the second compression tank Of the initial supply pressure)
14. The gas separation membrane module as claimed in claim 13, wherein a membrane area of the first gas separation membrane module is set by the following equation 1, and a membrane area of the second gas separation membrane module is set by the following equation (2) A method of recovering a target gas using the method.
(Equation 1)

( ₁ is the membrane area of the first gas separation membrane module, v ₀ is the initial flow rate of the feed gas, _Po is the initial supply pressure of the first compression tank,? ₁ is the first SC value,? ₂ is the second SC value, P _{B, 1} is the permeability of the first recovered gas, α ₁ is the selectivity of the first gas separation membrane module, and X _F is the target gas concentration in the feed gas)
(Equation 2)

(A ₂ is the membrane area of the second gas separation membrane module, A ₁ is the membrane area of the first gas separation membrane module, θ ₂ is the second SC value, X _F is the target gas concentration in the feed gas _{, 2} is the permeability of the second recovered gas,? ₁ is the selectivity of the first gas separation membrane module, and? ₂ is the selectivity of the first gas separation membrane module.
14. The method according to claim 13, wherein the membrane area of the second gas separation membrane module is set through the following equation.

(A ₂ is membrane area, A ₀ is the first membrane area of the gas separation membrane module, θ ₂ is the second SC value, X _F is the target gas concentration in the feed gas, α ₁ of the second gas separation membrane module is a first gas separation membrane Module and second gas separation membrane module)
The method of claim 13 wherein the feed gas including the target base is a waste gas containing waste gas or fluoride gas with the SF _6, wherein the target gas is a target using a gas separation membrane module, characterized in that SF ₆ or fluoride gas Gas recovery method.

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