KR101482612B1 - Apparatus and method for recovery of sulfur hexafluoride - Google Patents

Abstract

The present invention relates to an apparatus and a method for separating and recovering SF6, which can recover SF6 concentrated at constant ratio by controlling pressure applied to a separation module in response to flow change of injected gas, and controlling a number of operated separation modules when recovering SF6 by using a plurality of separation modules. According to the present invention, the apparatus for separating and recovering SF6 comprises a waste gas supply unit supplying waste gas including SF6; a plurality of separation modules separating waste gas supplied from the waste gas supply unit into recovery gas and penetration gas; a flow measurement means measuring flux of waste gas supplied to a plurality of separation modules; a vacuum pump applying vacuum pressure to each separation module; and a control means controlling the vacuum pump so that vacuum pressure is applied to the separation module.

Description

FIELD OF THE INVENTION [0001] The present invention relates to an apparatus and a method for recovery of sulfur hexafluoride

The present invention relates to an apparatus and method for separating and recovering SF ₆ , and more particularly, to a system and method for separating and recovering SF ₆ by regulating a pressure applied to a separation membrane module The present invention relates to an SF ₆ separation and recovery apparatus and method capable of recovering concentrated SF ₆ at a certain ratio by selectively controlling the number of separation membrane modules to be operated.

SF ₆ is a typical electrical insulating material of electric power equipment and is used in the cleaning process of semiconductor wafers and LCD panels. SF ₆ is known to have an impact on global warming more than 23900 times that of carbon dioxide, and it has been identified as one of the six substances with the highest global warming index in the Conference of the Parties to the Convention on Climate Change held in Kyoto in 1997 . Therefore, treatment for SF ₆ contained in the waste gas is urgently required.

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

SF ₆ has a technology for recovering a technique for recovering only the mixed gas of SF ₆ containing the SF _6, naengbeop seam common gas separation corporation, PSA (pressure swing adsorption) method, a membrane separation method or the like can be applied.

First, the seaworthiness method is disclosed in Korean Patent No. 10-0512294, which is suitable for large-capacity and high-concentration processing, but requires a high investment cost and low energy consumption efficiency. Next, the PSA method, which separates SF ₆ by adsorbing nitrogen (N ₂ ) or the like having a small molecular size by using an adsorbent such as zeolite, desorbs nitrogen adsorbed in the decompression process by alternately applying pressurization and decompression, Is a technique for separating a mixed gas such as N ₂ / SF ₆ by adsorbing a new nitrogen in the pressurization process of the gas. In this PSA method, SF ₆ leaks during the desorption process and a recovery rate of 90% or more can be obtained. However, when the concentration of SF ₆ in the mixed gas introduced into the system is low, the concentration of SF ₆ in the recovered gas is increased Of the total volume of the liquefaction process.

The membrane separation method is a technique for separating and recovering SF ₆ by using a separation membrane, which can be separated into SF ₆ at a high concentration and has advantages of high recovery rate and continuous operation. However, in order to separate SF ₆ from the membrane by the membrane separation method, a pressure difference between the inside and outside of the membrane is required. When the inlet gas is pressurized, continuous operation of the membrane separation apparatus is difficult and application is difficult when the apparatus connected to the supply side is sensitive to pressure . Also, when the flow rate of the waste gas changes and the flow rate of the gas supplied to the separation membrane module is not constant, the flow rate of the recovered gas and the SF ₆ concentration also vary.

Korean Patent No. 10-0512294

Membrane The present invention is operated as one made in view the above problems, with the box in response to regulate the pressure applied to the membrane module in flow rate of the injected gas as the recovered SF ₆ by using a plurality of separation membrane module And an SF ₆ separation / recovery device and method capable of recovering concentrated SF ₆ at a constant ratio by selectively controlling the number of modules.

According to an aspect of the present invention, there is provided an SF ₆ separation and recovery apparatus including a waste gas supply unit for supplying waste gas including SF ₆ , a plurality of separation membrane modules for separating waste gas supplied from the waste gas supply unit into a recovery gas and a permeable gas, A flow rate measuring means for measuring a flow rate of waste gas supplied to the plurality of separation membrane modules, a vacuum pump for applying vacuum pressure to each of the separation membrane modules, and a waste gas flow rate (Ff) calculates a pressure difference (ΔP) by substituting the following equation, and calculates a difference value (ΔP-ΔP _m) between the pressure difference (ΔP) both internal and external pressure of the pre-set membrane module difference (ΔP _m), the difference ( And a control unit controlling the vacuum pump so that a vacuum pressure corresponding to? P -? P _m is applied to the separation membrane module.

(Formula)? P = Ff · SC / (Q · A)

Where Q is the permeability of the membrane module, and A is the effective area of the membrane module. [0054] In the membrane module of the present invention,

The control means can selectively control the number of the membrane modules operating under conditions that satisfy the process for the measured waste gas flow rate and the vacuum pressure applied to each membrane module. In addition, the total maximum treatment flow rate of the separation membrane module is operated (Ff _max) is greater than the flow rate of the waste gas supplied from the waste gas supply. The plurality of separation membrane modules are arranged in parallel, and waste gas is independently injected into each separation membrane module.

And the control means, the maximum that can be that the measured waste gas flow driving the membrane module processing process flow if it exceeds (Ff _max), sikimyeo additional driving a separation membrane module, the flow rate of the measured waste gas flow rate and the maximum processing (Ff _max ) is calculated through the above equation, and the calculated vacuum pressure can be applied to the further operating separation membrane module.

Further, the control means, measured the case of the waste gas flow rate is greater than the driving up processing flow (Ff _max) in the membrane module can process, it sikimyeo additional driving the separation membrane module, corresponding to the measured waste gas flow vacuum pressure And the calculated vacuum pressure can be distributed to the separation membrane module to be operated and applied.

It said plurality of separation membrane module is provided in the constant temperature device capable of temperature control, the maximum treatment flow rate of the separation membrane module (Ff _max) through the temperature control of the constant-temperature equipment can be increased or decreased. The SC value is fixed to a constant value.

A plurality of separation membrane module groups including the plurality of separation membrane modules may be serially arranged in series and a recovery gas collected by the first separation membrane module group may be injected into the second separation membrane module group. In addition, the separation membrane module is exposed under atmospheric pressure and a vacuum pressure is applied to the separation membrane module, and the pressure difference between the inside and outside of the separation membrane module is a difference between the atmospheric pressure and the applied vacuum pressure.

SF ₆ separating and recovering method according to the present invention, in the SF ₆ Separation method for separating a waste gas containing SF ₆ by using a plurality of separation membrane module to the recovered gas and the permeate gas, each of the separation membrane in response to the off-gas flow rate to be supplied Wherein the pressure difference between the inside and the outside of the module is set to be a difference between the atmospheric pressure and the vacuum pressure applied to the membrane module, Calculating a pressure difference? P by substituting the measured waste gas flow rate (Ff) into the following equation, and calculating the pressure difference? P ) and it calculates a difference value (ΔP-ΔP _m) between the internal and external pressure difference (ΔP _m), the predetermined separation membrane module, the vacuum pressure corresponding to the difference value (ΔP-ΔP _m) It characterized by comprising the step of applying the membrane module group.

(Formula)? P = Ff · SC / (Q · A)

Where Q is the permeability of the membrane module, and A is the effective area of the membrane module. [0054] In the membrane module of the present invention,

If the measured waste gas flow exceeds the total maximum treatment flow (Ff _max ) of the membrane module being operated, the extra membrane module is operated and a vacuum pressure corresponding to the difference (ΔP-ΔP _m ) is applied to the newly operated membrane module can do.

The SF ₆ separation and collection apparatus and method according to the present invention have the following effects.

The SC value can be kept constant by controlling the vacuum pressure applied to the inside of the separation membrane module in response to the change of the waste gas flow rate supplied to the separation membrane module, thereby increasing the SF ₆ concentration ratio.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of an SF ₆ separation / recovery device according to an embodiment of the present invention; FIG.
FIG. 2 is a flow chart for explaining the SF ₆ separation / recovery method according to an embodiment of the present invention; FIG.
FIG. 3 is a graph showing a relation between a process flow rate Ff and a pressure difference (AP) of a separator module according to a change in SC value.
FIG. 4 is a graph showing the relationship between the process flow rate Ff and the pressure difference (AP) of the separator module according to the increase of the separator module operated in a state where the SC value is fixed.
5 is a reference view showing a mode of utilizing the maximum processing flow rate of the separation membrane module when the waste gas flow rate is increased.
6 is a reference view showing a mode in which the vacuum pressure applied to the separation membrane module is distributed and applied when the waste gas flow rate is increased.

A method for recovering SF ₆ gas contained in the waste gas using a separation membrane module is as follows. The waste gas is injected into the separation membrane module. The separation membrane module separates the waste gas into SF ₆ (recovery gas) and other gases . According as the number of the SF ₆ with a membrane module, SF ₆ in order to control the concentration, it is important to maintain a constant flow rate of the flow rate or transmission gas in the waste gas flow rate compared to recovery gas, the flow rate or transmission gas in the waste gas flow rate compared to recovery gas Is controlled by a SC (Stage-cut) regulator. That is, by specifying the SC value through the SC (Stage-cut) regulator, the flow rate of the recovered gas or the flow rate of the permeated gas can be kept constant compared with the waste gas flow rate.

The waste gas injected into the membrane module is set to be injected at a constant flow rate, but has characteristics that vary in real time due to various factors such as equipment condition, temperature, pressure, etc. of the waste gas supply side. And the flow rate of the recovered gas (or the flow rate of the permeated gas) can not be kept constant.

The present invention proposes a technique capable of maintaining the flow rate of the recovered gas at a constant level by controlling the pressure inside the separating membrane module and the number of the operated separating membrane modules in response to the change of the waste gas flow rate. That is, even if the flow rate of the waste gas changes in real time, the pressure inside and outside the separation membrane module is adjusted so as to correspond to the waste gas flow rate, and the SC value (permeate gas flow rate / injection gas flow rate) The SF ₆ separation and recovery apparatus and method are disclosed.

Hereinafter, an apparatus and method for separating and collecting SF ₆ according to an embodiment of the present invention will be described in detail with reference to the drawings.

1, the SF ₆ separation and collection apparatus according to an embodiment of the present invention includes a waste gas supply unit 110, a plurality of separation membrane modules 120, a recovery gas storage tank 130, a flow rate measurement unit 140, A vacuum pump 150, and a control means 160. The vacuum pump 150 is a vacuum pump.

The waste gas supply unit 110 supplies waste gas including SF ₆ to the plurality of separation membrane modules 120. The plurality of separation membrane modules 120 separates the waste gas into SF ₆ and other gases It plays a role. The plurality of separation membrane modules 120 are arranged in parallel, and waste gas is independently injected into each separation membrane module 120. The recovered gas storage tank 130 serves to store the recovered gas recovered by the respective separation membrane modules 120.

Each of the separation membrane modules 120 separates the gas using the difference in diameter of gas molecules. The SF ₆ having a relatively large diameter is recovered without being permeated through the pores of the separation membrane module 120, A gas such as O ₂ , N ₂ , and CO ₂ permeates the pores of the separation membrane module 120, and SF ₆ and other gases are separated. Specifically, the separation membrane module 120 is a hollow-type separation membrane aggregate in which pores are formed on its surface, and gases such as O ₂ , N ₂ , and CO ₂ except SF ₆ gas are discharged through the pores of the separation membrane, SF ₆ having a large diameter of the molecule is recovered at one end of the separation membrane without passing through the pores. The gas recovered at one end of the separation membrane is referred to as a recovery vessel body, and the gas discharged through the pores of the separation membrane is referred to as a permeation vessel. The SF ₆ content is high in the recovered gas, and the SF ₆ content is small in the permeated gas.

The configuration of the waste gas supply unit 110, the separation membrane module 120 and the recovery gas storage tank 130 may be a basic configuration of the SF ₆ separation and recovery process using the separation membrane module 120. In the present invention, the configuration of the flow rate measuring means 140, the pressure measuring means, the vacuum pump 150, and the control means 160 is added to the configuration of the present invention so that the ratio of the flow rate of the recovered gas to the flow rate of the injected gas is maintained constant, The concentration of SF ₆ stored in the gas storage tank 130 can be controlled.

Prior to the description of the flow measuring means 140, the pressure measuring means, the vacuum pump 150 and the control means 160, the processing flow Ff of each of the separation membrane modules 120 and the internal and external pressures of the separation membrane modules 120 Mathematical theorem for the difference (P) is needed. The processing flow Ff of the separation membrane module 120 and the pressure difference AP between the inside and the outside of the separation membrane module 120 are applied to the number of the separation membrane module 120 to be operated and the control of the vacuum pump 150, 120 and the control of the vacuum pump 150, it becomes possible to keep the ratio of the permeate gas flow rate to the injection gas flow rate, that is, the SC value constant.

The processing flow rate Ff of the separation membrane module 120 means the flow rate of the waste gas supplied to the separation membrane module 120 and expresses the flow rate Fp of the permeated gas passing through the separation membrane module 120, And the recovered gas flow rate Fr recovered by the separation membrane module 120. [ On the other hand, the SC (Stage-cut) value means the ratio of the permeate flow rate Fp to the treatment flow rate Ff as shown in Equation 2. According to the gas permeation theory, the permeate flow rate Fp passing through the separation membrane module 120 is defined as in Equation 3, and the Q value in Equation 3 is the permeability of the waste gas according to the characteristics of the separation membrane module 120 itself , The A value represents the effective area of the membrane module 120, and the ΔP value represents the pressure difference between the inside and the outside of the membrane. When the pressure difference? P is the maximum in Equation 3, the permeate flow rate Fp is maximized, which is expressed by Equation 4 below.

(Formula 1) Treatment flow rate (Ff) = permeate gas flow rate (Fp) + recovered gas flow rate (Fr)

(2) SC = Fp / Ff

(Expression 3) Fp = Q? A? P

(Equation 4) Fp _max = Q? A? P _max

Maximum Flow (Ff _max) of the separation membrane module 120 on the basis of the above equations (1) to (4) can be summarized as shown in equation (5). In addition, the pressure difference AP of the separation membrane module 120 with respect to the processing flow rate Ff is summarized as shown in Equation (6).

(Expression 5) Ff _max = Fp _max / SC = Q? A? P _max / SC

(6)? P = Ff? SC / (Q? A)

The processing flow Ff according to Equation 6 and the pressure difference AP between the separation membrane module 120 can be expressed as shown in FIGS. 3 and 4 show vacuum pressures applied to the inside of the separation membrane module 120 in a state where the outside of the separation membrane module 120 is maintained at an atmospheric pressure. 2 shows the required vacuum pressure according to the treatment flow rate Ff for maintaining the flow rate (0.5, 0.6, 0.7, 0.8, 0.9) The number of the separation membrane modules 120 >. 3, the required vacuum pressure increases as the SC value increases, that is, as the ratio of the injected gas flow rate to the recovered gas flow rate becomes smaller. 4, the required vacuum pressure decreases as the number of the separation membrane modules 120 operated increases.

The flow rate measuring means 140, the pressure measuring means, the vacuum pump 150, and the like are mathematically provided on the basis of the processing flow rate Ff of the separation membrane module 120 and the pressure difference? P on the inside and the outside of the separation membrane module 120, And the control means 160 will be described below.

The flow rate measuring means 140 measures a waste gas flow rate injected into the separation membrane module 120 from the waste gas supply unit 110. Here, the waste gas flow rate corresponds to the treatment flow rate Ff of the separation membrane module 120. The pressure measuring means measures the internal and external pressure difference (ΔP _m) of the respective membrane modules 120, the vacuum pump 150 is applied to the air pressure (vacuum pressure), camp on the inside of the membrane module 120, wherein each . In addition, by the operation of the vacuum pump 150, the permeable gas of the separation membrane module 120 is discharged through one side of the vacuum pump 150.

Lastly, the control means 160 calculates the waste gas flow rate Ff measured by the flow rate measuring means 140 and the pressure difference? P _m of the inside and outside of the membrane module 120 measured by the pressure measuring means calculating a difference value (ΔP-ΔP _m) between the pressure difference (ΔP) values and the measured pressure difference (ΔP _m) satisfying the equation (6) in conjunction with the formula 6, and corresponds to the difference (ΔP-ΔP _m) To operate the vacuum pump 150 so that the pressure applied to the separation membrane module 120 is applied. That is, by substituting the waste gas flow rate Ff measured by the flow rate measuring means 140 into the equation (6) to calculate the pressure difference? P satisfying the equation (6), and calculating the pressure difference? calculates a difference value (ΔP-ΔP _m) between the measured pressure difference (ΔP _m), the difference value between the vacuum pump 150, the so pressure is applied to the membrane module (120) corresponding to the (ΔP-ΔP _m) It is possible to keep the SC value constant by operating.

The pressure difference between the inside and the outside of the separator module 120 is controlled by the vacuum pressure applied by the vacuum pump 150. In this case, when the separator module 120 is exposed to atmospheric pressure and the vacuum pressure inside the separator module 120 is set, In this case, since the vacuum pressure applied by the vacuum pump 150 is specified, the pressure difference between the inside and the outside of the separation membrane module 120 is set to a preset pressure difference rather than the measured pressure difference as described above It can be regarded as a pressure difference (difference between normal pressure and applied vacuum pressure). Therefore, the variable to be processed by the control means 160 is one of the waste gas flow rate Ff measured by the flow rate measuring means 140 and the waste gas flow rate Ff measured by the flow rate measuring means 140 to And calculate the difference between the pressure difference? P satisfying Equation 6 and the set pressure difference, and operate the vacuum pump 150 to apply the pressure corresponding to the difference to the separation membrane module 120 .

In addition to the function of calculating the difference between the pressure difference DELTA P satisfying Equation 6 and the set pressure difference and operating the vacuum pump 150, the control means 160 sets the SC value, And controls the operation of the membrane module 120. The SC value may be adjusted by a separate stage-cut regulator.

The processing flow Ff of the separation membrane module 120 and the pressure difference AP of the separation membrane module 120 have the relationship of Equation 6 and a plurality of the separation membrane modules 120 are arranged in parallel, The processing flow rate Ff of the separable membrane module 120 that can be processed also doubles as the number of the separation membrane modules 120 to be operated is increased as the performance is the same. The processing flow rate, vacuum pressure, separation membrane module 120, Of the number of pixels.

The control means 160 is the maximum processing flow (Ff _max) and at the maximum pressure difference (ΔP _max), the information is secured state, which can be applied to each of the separation membrane module 120, a measurement of the respective membrane modules 120 The number of membrane modules 120 for treating the waste gas flow rate and the vacuum pressure applied to each membrane module 120 are determined. For example, measuring the waste gas flow is a membrane module 120 is the maximum number of processing flow if it exceeds (Ff _max), the used gas flow rate of the two operations the second membrane module 120 and measuring the first in handle is applied to the pneumatic (calculated using equation 6) binary corresponding to the flow rate corresponding to the difference value of the separation membrane module, the maximum processing flow (Ff _max) of 120 to the second membrane module 120 (see FIG. 5). In this way, the operation of the plurality of membrane modules 120 and the vacuum pressure applied to each membrane module 120 can be set.

Meanwhile, when vacuum pressure is applied to the plurality of separation membrane modules 120, when the maximum processing flow rate of the first separation membrane module 120 is exceeded as described above, the second separation membrane module 120 is operated, The flow rate of the waste gas measured without setting the separation membrane module 120 to process the maximum processing flow rate may be divided into a plurality of separation membrane modules 120 120) can be set to perform processing in a shared manner (see FIG. 6). For example, in the latter case, when the maximum process flow rate of the membrane module 120 is 100 and the measured waste gas flow rate is 150, 50 waste gas flows are supplied to each of the first, second, and third membrane modules 120, A suitable vacuum pressure can be applied to each membrane module 120. In the latter scheme, the waste gas flow rate to be distributed to each separation membrane module 120 can be arbitrarily determined, and in consideration of the efficiency of the separation membrane module 120, the waste gas flow rate is distributed equally to each of the separation membrane modules 120 . The former mode and the latter mode can be selectively applied in consideration of the maintenance cost of the separation membrane module 120 and the vacuum pressure setting cost.

The plurality of separation membrane modules 120 are arranged in parallel, but the plurality of separation membrane modules 120 arranged in parallel may be repeatedly arranged. For example, the group of the first separator module 120, the group of the second separator module 120, and the third separator module 120 are arranged in series, and a plurality of The processing flow Ff of the separation membrane module 120 and the separation membrane module 120 of the separation membrane module 120 provided in each group of the separation membrane modules 120 can be configured in a manner that the separation membrane modules 120 are arranged in parallel. ) Inside and outside pressure difference DELTA P and the corresponding vacuum pressure is applied. The concentration of the recovered gas can be increased by arranging the plurality of the separation membrane modules 120 in series.

The plurality of separation membrane modules 120 or the plurality of separation membrane modules 120 may be provided in a thermostatic device and the maximum processing flow rate Ff of each separation membrane module 120 may be controlled through temperature control of the thermostatic device. _max . When the temperature of the separation membrane module 120 is increased, the process flow rate Ff increases and when the temperature decreases, the process flow rate Ff also decreases. Such characteristics are maintained by maintaining a constant SC value corresponding to the waste gas flow rate As another control factor in addition to the vacuum pressure of the membrane module 120 and the number of the membrane modules 120 to be operated. The temperature control of the separation membrane module 120 through the thermostat will be described in detail in the SF ₆ separation and recovery method described later.

The SF ₆ separation and recovery apparatus according to an embodiment of the present invention has been described. Hereinafter, the SF ₆ separation / recovery method according to an embodiment of the present invention will be described. The SF ₆ separation and recovery method of the present invention proceeds under the basis of the apparatus constitution of the waste gas supply unit and the plurality of separation membrane modules.

First, as shown in FIG. 2, the maximum processing flow rate information of each separation membrane module is secured (S201). The maximum processing flow of each membrane module can be calculated from Eq.

(Expression 5) Ff _max = Fp _max / SC = Q? A? P _max / SC

This is the same status, setting the flow rate of the waste gas supplied from the waste gas supply, and set the internal and external pressure difference (ΔP _m) of each membrane module (S202). The pressure difference between the inside and the outside of the separator module can be set in such a manner that the outside of the separator module is exposed to atmospheric pressure and the vacuum pressure is applied inside the separator module. In addition, the SC value is fixed to a constant value.

The waste gas flow rate is set within a range that can be processed by one or a plurality of membrane module, and is set within a range of vacuum pressure that can be applied inside the membrane module. For example, two separator modules may be operated for a set specific waste gas flow rate and a specific vacuum pressure may be applied to the six separator modules.

When the waste gas flow rate and the corresponding number of the membrane modules to be operated and the vacuum pressure of the membrane module are set, the waste gas is supplied according to the set flow rate, and the membrane module is operated under the set conditions (number of membrane modules and vacuum pressure) S203).

In a state where the separation membrane module is operated, the flow rate of the waste gas injected into the separation membrane module to be operated and the pressure difference between the inside and the outside of the separation membrane module to be operated are measured in real time (S204). As described above, the waste gas supplied to the separation membrane module from the waste gas supply unit has properties that vary depending on various factors even if the supply flow rate is set. Further, the measurement of the inner and outer pressure differences of the separation membrane module may be replaced by checking the gauge of the vacuum pump that applies vacuum pressure to the separation membrane module when the separation membrane module is provided under normal pressure. That is, when the separation membrane module is exposed under atmospheric pressure and the vacuum pressure inside the separation membrane module is set, the pressure difference between the inside and the outside of the separation membrane module means the difference between the vacuum pressure and the normal pressure applied by the vacuum pump.

In instances of preparation of the measured waste gas flow rate and the first predetermined flow rate, calculate the pressure difference (ΔP) of the membrane module by applying the waste gas flow rate (Flow, Ff) measured in Equation 6 and the predetermined pressure differential (ΔP _m) and it calculates the difference (ΔP-ΔP _m) with. Here, it may indicate a difference between the vacuum pressure applied to the atmospheric pressure and the membrane module pressure difference (ΔP _m) of the membrane module set in advance.

(6)? P = Ff? SC / (Q? A)

Increasing the vacuum pressure of the membrane module as the difference (ΔP-ΔP _m) to compensate for the difference (ΔP-ΔP _m) of the pressure difference (ΔP _m) previously set with the pressure difference (ΔP) corresponding to the measured waste gas flow rate (S205). At this time, if it exceeds the total of the maximum treatment flow rate (Ff _max) of the membrane module is the measured waste gas flow driving binary driving the extra membrane module and corresponding to the difference (ΔP-ΔP _m) in the membrane module is a new operation Apply air pressure. In addition, when the measured waste gas flow rate is significantly reduced, the number of separation membrane modules to be operated can be reduced and the vacuum pressure can be reduced.

As described above, the processing flow Ff of the separation membrane module and the pressure difference DELTA P of the separation membrane module have the relationship of Equation 6, and when the plurality of separation membrane modules are arranged in parallel and the performance of each separation membrane module is the same, As the number of modules increases, the processing flow rate Ff of the separable membrane module that can be processed also doubles, and has a relationship between the processing flow rate, the vacuum pressure, and the number of separation membrane modules as shown in Fig.

When the measured waste gas flow rate exceeds the total maximum treatment flow rate (Ff _max ) of the separation membrane module to be operated, the additional operation of the separation membrane module can be performed under conditions satisfying the treatment of the measured waste gas flow rate, The vacuum pressure of the module can be set. That is, it is possible to selectively control the number of the membrane modules to be operated and the vacuum pressure applied to each membrane module, based on the assumption that the measured waste gas flow rate can be processed.

On the other hand, the maximum processing flow rate (Ff _max ) of the separation membrane module can be controlled by controlling the temperature of the separation membrane module. Flow (Ff) of the separation membrane module has a characteristic which is proportional to the temperature, by using this characteristic it is possible to increase the maximum treatment flow rate of the separation membrane module (Ff _max). Increasing the maximum treatment flow rate of the separation membrane module (Ff _max) is no guarantee is to reduce the number of the separation membrane module is operated can be increased the vacuum pressure applied to each of the separation membrane module.

Even if the measured waste gas flow rate changes with respect to the initially set waste gas flow rate, by adjusting the number of the separation membrane modules operated by the amount corresponding to the changed waste gas flow rate and the vacuum pressure applied to each separation membrane module, And finally, the concentration of SF ₆ can be constantly controlled.

110: waste gas supply unit 120: separation membrane module
130: recovery gas storage tank 140: flow rate measuring means
150: Vacuum pump 160: Control means

Claims (12)

A waste gas supply unit for supplying waste gas including SF ₆ ;
A plurality of separation membrane modules for separating waste gas supplied from the waste gas supply unit into a recovery gas and a permeable gas;
Flow rate measuring means for measuring a flow rate of waste gas supplied to the plurality of separation membrane modules;
A vacuum pump for applying vacuum pressure to each of the separation membrane modules; And
Between the flow rate of the waste gases measured by the measurement means the flow rate (Ff) calculating a pressure difference (ΔP) by applying the following formula to, and the pressure difference (ΔP) with a predetermined separation membrane and out pressure of the modules difference (ΔP _m) difference value (ΔP-ΔP _m) the calculation and, SF to the vacuum pressure corresponding to the difference value (ΔP-ΔP _m) characterized in that comprises a control means for controlling the vacuum pump to be applied to the separation membrane module ₆ Separation and collection device.
(Formula)? P = Ff · SC / (Q · A)
Where Q is the permeability of the membrane module, and A is the effective area of the membrane module. [0054] In the membrane module of the present invention,
2. The apparatus of claim 1, wherein the control means selectively controls the number of separator modules to be operated and the vacuum pressure applied to each separator module,
Total maximum treatment flow rate of the separation membrane module is operated (Ff _max) is separated and recovered SF ₆ wherein greater than the off-gas flow rate supplied from the waste gas supply.
delete The SF ₆ separation and recovery device according to claim 1, wherein the plurality of separation membrane modules are arranged in parallel, and waste gas is independently injected into each separation membrane module.
2. The apparatus according to claim 1,
If the measured waste gas flow rate exceeds the maximum process flow rate (Ff _max ) that the separator module on which it operates can further process the separator module,
The measured waste gas flow rate and the maximum treatment flow rate of SF ₆ separation which comprises applying a vacuum pressure that corresponds to the difference (Ff _max) for calculation by the above equation, and in addition operation above the vacuum pressure the calculated separation membrane module Recovery device.
2. The apparatus according to claim 1,
If the measured waste gas flow rate exceeds the maximum process flow rate (Ff _max ) that the separator module on which it operates can further process the separator module,
Calculating a vacuum pressure corresponding to the measured waste gas flow rate through the above equation, and distributing the calculated vacuum pressure to the separation membrane module to be operated and applying the SF ₆ separation filter.
The method according to claim 1, wherein the plurality of separation membrane modules are provided in a constant temperature apparatus capable of controlling the temperature, and the maximum processing flow rate (Ff _max ) of the separation membrane module can be increased or decreased through temperature control of the constant temperature apparatus SF ₆ separation and recovery device.
The SF ₆ separation and recovery device according to claim 1, wherein the SC value is fixed to a constant value.
The method of claim 1, wherein a membrane module group are arranged in series repeat composed of the plurality of separation membrane module, the number of gas recovered by the first membrane module group are both SF ₆ separated, characterized in that to be injected into the first membrane module group number Device.
The method of claim 1 wherein the separation membrane module is exposed to atmospheric pressure is applied to the vacuum pressure in the inside of the separation membrane module, SF ₆ separation of internal and external pressure differential, wherein a normal pressure and applying the binary difference of the air pressure of the separation membrane module number Device.
An SF ₆ separation and recovery method for separating waste gas containing SF ₆ into a recovery gas and a permeable gas using a plurality of separation membrane modules,
Wherein the pressure difference between the inside and the outside of the separator module is set in correspondence with the amount of the waste gas to be supplied and the difference between the inside pressure and the vacuum pressure applied to the separator module;
Operating the plurality of separation membrane modules in a state where the permeate gas flow rate is kept constant with respect to the supplied gas flow rate;
Measuring a waste gas flow rate supplied to the plurality of separation membrane modules; And
The measured value of the waste gas flow rate Ff is substituted into the following equation to calculate the pressure difference ΔP and the difference value ΔP-ΔP between the pressure difference ΔP and the internal and external pressure difference ΔP _m of the previously set separation membrane module _m) the output and, SF ₆ separation and recovery method of a vacuum pressure that corresponds to the difference value (ΔP-ΔP _m) characterized in that comprises the step of applying to the membrane module.
(Formula)? P = Ff · SC / (Q · A)
Where Q is the permeability of the membrane module, and A is the effective area of the membrane module. [0054] In the membrane module of the present invention,
12. The method of claim 11, when it exceeds the total of the maximum processing flow (Ff _max) of the membrane module is the measured used gas flow rate operation in the difference (ΔP-ΔP _m) in the membrane module is operated for replacement of the membrane module and a new operation SF ₆ separated and recovered characterized in that for applying a binary equivalent of air pressure.

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