KR101515117B1 - Purification method for off-gas and apparatus for purification of off-gas - Google Patents

Abstract

This invention relates to a waste gas purification method and an apparatus thereof. More specifically, the present invention relates to the waste gas purification method and apparatus to remove hydrogen chloride and separate high-purity hydrogen from the waste gas that is discharged after a chemical vapor deposition from a polysilicon deposition process.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an off-

The present invention relates to a purification method and purification apparatus for waste gas. More particularly, the present invention relates to a purification method and a purification apparatus for a waste gas which is capable of removing hydrogen chloride from discharged waste gas and separating high purity hydrogen after performing a polysilicon deposition process by a chemical vapor deposition reaction.

One known method of producing polysilicon for solar cells is by the deposition of polysilicon in a chemical vapor deposition (CVD) reactor, known as the Siemens process.

In the Siemens process, silicon filaments are typically exposed to trichlorosilane along with the carrier gas at elevated temperatures above 1000 ° C. The trichlorosilane gas decomposes and deposits silicon on a heated silicon filament as shown in the following Formula 1 to grow a heated silicon filament.

[Formula 1]

2HSiCl ₃ - > Si + 2HCl + SiCl ₄

After the polysilicon is deposited by chemical vapor deposition as described above, chlorosilane compounds such as dichlorosilane, trichlorosilane, or silicon tetrachloride, hydrogen, and hydrogen chloride are discharged as reaction by-products.

The off-gas (OGR) containing such a chlorosilane compound, hydrogen and hydrogen chloride is generally used for 1) condensing and compression process, 2) hydrogen chloride absorption and distillation, step 3) is recovered and recycled hydrogen (H ₂₎ adsorption (adsorption) process, 4) through the four stages of separation of the chlorosilane-based compound (separation) process.

More specifically, the waste gas discharged from the polysilicon deposition reactor is transferred to a condensation and compression process, cooled, and then introduced into a knock-out drum. The chlorosilane compound condensate stream is transferred to the hydrogen chloride (HCl) distillation column and the non-condensed stream is transferred to the bottom of the hydrogen chloride absorption column. At this time, the composition of hydrogen (H ₂ ) is about 90 mol% or more.

The condensed phase stream from which the hydrogen chloride component has been removed from the hydrogen chloride distillation column is mixed while being sprayed at the top of the absorption column and absorbs and removes the chlorinated silane based compound component and hydrogen chloride in the non-condensed stream.

Most of the hydrogen chloride stream from which the chlorinated silane compound and hydrogen chloride are removed flows into a column packed with activated carbon to adsorb the remaining chlorinated silane compound and hydrogen chloride, and recover high purity hydrogen .

The hydrogen purification method described above has been adopted for the separation and purification of polysilicon waste gas by a pressure swing adsorption (PSA) process.

3 shows a conventional waste gas purifying apparatus.

3, a conventional waste gas purification apparatus 300 includes a knockout drum 315, an absorption tower 325, a primary distillation column 345, an adsorption column 355, and a secondary distillation column 360 .

The waste gas 301 discharged from the polysilicon deposition reactor 305 is cooled in the first cooler 310 and then flows into the knockout drum 315 to be supplied to the gas phase non- And separated into a liquid phase condensate stream 303 containing an excessive amount of silane-based compound. At this time, most of the hydrogen chloride contained in the waste gas 301 is distributed in the non-associated axial flow 302.

The non-coherent non-axial stream 302 discharged from the top of the knock-out drum 315 is injected into the absorption tower 325 after further cooling and pressurization in the second cooler 320. At this time, most of the hydrogen chloride and silane chlorosilane components contained in the non-migrated stream 302 are removed by the chlorinated silane-based stream 307 sprayed from the first distillation column 345 described later. On the other hand, the hydrogen stream 304 discharged from the upper part of the absorption tower 325 is finally refined and recycled in the adsorption tower 355.

The liquid stream 303 discharged from the lower portion of the knockout drum 315 is mixed with the flow 306 discharged from the absorption tower 325 via the pump 350 and then injected into the primary distillation column 345. The gaseous hydrogen chloride is separated and discharged from the upper portion of the primary distillation column 345 and the chlorinated silane-based stream 307 from which hydrogen chloride is removed is discharged from the lower portion. At this time, the primary distillation tower (345) process consumes about 40% or more of the total refining process, and operates in a high energy process which consumes the most energy. The majority of the chlorosilane-based stream 307 is again transported to the absorber 325 through the pump 335 and the cooler 330 to be used for the absorption of hydrogen chloride and chlorosilane in the non-smelting stream 302, Is transferred to the tea distillation tower (360) and is recycled after being separated into the iodine / trichlorosilane and silicon tetrachloride.

In the conventional purification method as described above, the condensed stream 307 from which the hydrogen chloride component has been removed in the primary distillation tower 345 is sprayed to the absorption tower 325 to remove the hydrogen chloride contained in the non- . For such a process, there is a problem that the absorption tower 325 is cooled and the primary distillation tower 345 is required to be heated so that energy use is inefficient. Also, since the condensed phase stream in the upper part of the absorption tower 325 is excessively recycled in order to secure the purity of the non-condensed phase, it is a main cause of the increase of the energy cost in the waste gas purification process.

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for purifying waste gas which can effectively remove hydrogen chloride gas from a waste gas generated in a polysilicon deposition process by a chemical vapor deposition (CVD) And to provide a purification device.

In order to achieve the above object,

Separating the off-gas discharged after the polysilicon deposition process by the chemical vapor deposition (CVD) reaction into the non-associated axial flow and the condensed phase flow; And

And passing the condensed phase stream through a catalytic reactor including an ion exchange resin catalyst to remove hydrogen chloride.

Further, according to the present invention,

A separator for separating the off-gas discharged after performing the polysilicon deposition process by the chemical vapor deposition (CVD) reaction into the non-associated axial flow and the condensed phase flow; And

There is provided an apparatus for purifying waste gases comprising an ion exchange resin catalyst and a catalytic reactor for removing hydrogen chloride from the condensed phase stream.

According to the refining method and refining apparatus for waste gas of the present invention, the condensation and compression processes are performed to remove hydrogen chloride from the waste gas discharged from the polysilicon deposition reactor to perform isolation by the boiling point, The hydrogen chloride is converted to a chlorosilane compound by using a catalytic reactor and removed. This makes it possible to reduce various problems that can be caused by hydrogen chloride, such as corrosion, leaching of chlorosilane, deterioration of separation membrane, dissolution profile of impurities contained in activated carbon, etc., and hydrogen chloride is removed to produce high purity hydrogen It can be recycled.

Further, the purification method and purification apparatus for waste gas of the present invention can be realized by a relatively simple and low-energy apparatus, thereby reducing facility and process operation costs.

FIG. 1 shows an apparatus for purifying waste gas according to an embodiment of the present invention. Referring to FIG.
FIG. 2 illustrates an apparatus for purifying waste gas according to an embodiment of the present invention. Referring to FIG.
3 shows a conventional waste gas purifying apparatus.

In the present invention, the terms first, second, etc. are used to describe various components, and the terms are used only for the purpose of distinguishing one component from another.

Moreover, the terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to be limiting of the present invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprising," "comprising," or "having ", and the like are intended to specify the presence of stated features, But do not preclude the presence or addition of one or more other features, integers, steps, components, or combinations thereof.

Also in the present invention, when referring to each layer or element being "on" or "on" each layer or element, it is meant that each layer or element is formed directly on each layer or element, Layer or element may be additionally formed between each layer, the object, and the substrate.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Hereinafter, the method for purifying waste gas and the purification apparatus of the present invention will be described in more detail.

According to an embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: separating an off-gas discharged after a polysilicon deposition process by a chemical vapor deposition (CVD) process into a non- And passing the condensed phase stream through a catalytic reactor comprising an ion exchange resin catalyst to remove hydrogen chloride.

In the specification of the present invention, the off-gas refers to a gas discharged after a polysilicon deposition process, in particular, a polysilicon deposition process by a chemical vapor deposition (CVD) process, But it may be a gas containing hydrogen chloride (HCl), hydrogen (H ₂ ), and a chlorosilane-based compound. In addition, the waste gas includes all of the uncondensed gaseous state, the condensed liquid state, or the mixed state thereof, and it is possible to use not only the gas immediately discharged after the polysilicon deposition process but also other processes before the introduction into the catalytic reactor And a composition different from that immediately after the polysilicon deposition process is performed.

In the specification of the present invention, the condensed phase flow means a flow in which the waste gas flows in a liquid state through a process such as cooling, pressurization, separation, purification, etc., and a flow formed by one process, A flow formed by a multi-step process, or a flow in which they are mixed. In addition, the condensed phase stream can be used in the same sense as the liquid phase stream.

In the specification of the present invention, the non-antiferromagnetic flow refers to a flow in which the waste gas flows in a gaseous state through a process such as heating, depressurization, separation, purification and the like, and a flow formed by one process, Or a flow formed by the above-described multi-step process, or a flow in which these are mixed. In addition, the non-coherent flow can be used in the same sense as the gas flow.

One of the known methods for producing polysilicon is a chemical vapor deposition (CVD) method in which a silicon filament is heated and then a silicon precursor compound in a gaseous state such as trichlorosilane is injected and pyrolyzed to form silicon in the silicon filament And a method of precipitation.

As a by-product of the polysilicon deposition process by the chemical vapor deposition reaction, chlorinated silane-based compounds such as dichlorosilane (SiH ₂ Cl ₂ ), trichlorosilane (SiHCl ₃ ), and silicon tetrachloride (SiCl ₄ ) (HCl), hydrogen (H ₂ ), and the like.

Hydrogen and chlorosilane-based compounds can be separated from various components contained in such waste gas and recycled by chemical vapor deposition. However, since hydrogen chloride among the components contained in the waste gas is difficult to be recycled and may cause corrosion of the apparatus, it is preferably removed after the process, but it is not easy to remove due to low boiling point and molecular weight.

In the conventional waste gas purification method, the waste gas discharged from the polysilicon deposition reactor is transferred to a condensation and compression process to perform temperature separation. Accordingly, the condensed phase stream containing the chlorosilane compound is transferred to the distillation column to separate the hydrogen chloride from the upper portion, and the non-condensed stream is transferred to the lower portion of the absorption column.

The condensed phase stream from which the hydrogen chloride (HCl) component has been removed from the distillation column is mixed while being sprayed at the top of the absorption column and absorbs and removes the chlorosilane component and hydrogen chloride (HCl) in the non-condensed stream.

Since most of the chlorinated silane components and hydrogen chloride are removed from the hydrogen stream, the remaining hydrogen chloride and chlorinated silane compounds are introduced into the column filled with activated carbon, adsorbed by the activated carbon, and high purity hydrogen is recovered do.

In the conventional refining method as described above, in order to remove hydrogen chloride contained in the non-condensing water stream, the condensed phase stream in which the hydrogen chloride component is removed from the distillation column is supplied to the absorption tower by spraying. For this process, the absorber is required to be cooled, and the distillation tower needs to be heated, which is a problem of inefficient use of energy. Also, since the condensate phase is excessively recirculated to the absorber for securing the purity of the non-condensed stream, it is a main cause of the increase of the energy cost in the waste gas refining process.

However, the purification method of the waste gas of the present invention is relatively simple and can be implemented by a low-energy apparatus as compared with the conventional process, and thus it is possible to reduce facility and process operation costs.

In the purification method of the waste gas of the present invention, instead of separating the hydrogen chloride into gas phase by the difference of boiling point in the distillation column, the waste gas is separated into the non-condensed stream of the gas phase and the liquid phase condensed phase stream, By passing hydrogen chloride through a catalytic reactor comprising a resin catalyst to trichlorosilane or silicon tetrachloride, the emission of hydrogen chloride can be reduced.

 According to the refining method of the present invention, the off-gas discharged after the polysilicon deposition process is separated into a non-condensing stream in the gas phase and a condensed phase liquid phase.

More specifically, according to one embodiment of the present invention, the waste gas discharged from the chemical vapor deposition reactor flows into the knock-out drum after cooling, and is supplied to the knock-out drum in an excess amount of hydrogen- Liquid phase condensate phase.

The non-condensing stream discharged from the top of the knock-out drum is injected into the absorption tower after the additional cooling and pressurization. The hydrogen contained in the non-condensing stream is discharged from the top of the absorption tower, have. In addition, the hydrogen chloride contained in the non-condensing stream is discharged to the lower portion of the absorption tower and is finally removed through the following catalytic reactor.

The liquid phase condensate stream discharged from the bottom of the knockout drum is injected into a catalytic reactor comprising an ion exchange resin catalyst. Or may be mixed with the liquid stream discharged from the absorption tower and injected into a catalytic reactor comprising an ion exchange resin catalyst.

According to another embodiment of the present invention, the waste gas discharged from the chemical vapor deposition reactor is introduced into the knock-out drum after the first cooling to form a gas phase non-conformal stream containing excess hydrogen and a liquid phase containing an excessive amount of a chlorosilane- Phase flow of the condensed water.

The non-coherent stream of the vapor phase discharged from the top of the knock-out drum flows into the condenser and is secondarily cooled to a low temperature. The secondary cold cooling results in additional condensation of the hydrogen chloride and chlorosilane contained in the non-co-axial stream of the gaseous phase, and the condensed stream is recycled back to the knock-out drum. Thereafter, the non-associated axial flow is injected into the absorber, and the hydrogen contained in the non-co-axial flow is discharged from the top of the absorber and can be finally recycled at the adsorption tower. In addition, the hydrogen chloride contained in the non-condensing stream is discharged to the lower portion of the absorption tower and is finally removed through the following catalytic reactor.

The liquid phase condensate stream discharged from the bottom of the knockout drum is injected into a catalytic reactor comprising an ion exchange resin catalyst. Or may be mixed with the liquid stream discharged from the absorption tower and injected into a catalytic reactor comprising an ion exchange resin catalyst.

The liquid phase condensate stream is passed through a catalytic reactor comprising an ion exchange resin catalyst to remove hydrogen chloride contained in the liquid phase condensate stream.

As the ion exchange resin catalyst, a styrene-based polymer containing an amine group, a styrene-divinyl benzene-based polymer containing an amine group, or a mixture thereof may be used. The amine group is not particularly limited, but a tertiary or quaternary amine group may be preferable in view of the efficiency of the ion exchange resin. The styrene-based or styrene-divinylbenzene-based polymer containing the amine group may be produced by any method known in the art and is not particularly limited. For example, as an example of the above catalyst preparation method, a phthalimide process can be used. In this case, the divinylbenzene-crosslinked polystyrene resin reacts with a phthalimide or phthalimide derivative. The hydrolysis product of the primary polyvinylbenzylamine thus obtained is reacted with formaldehyde and formic acid. From this, a polystyrene resin having a tertiary amino group can be obtained. In addition, the ion exchange resin catalyst having a group of the amine is commercially readily available, for example, a trade name such as ^{Amberlyst ® A-21, Dowex M} -43, and LEWATIT ^® MP 62 WS.

According to the purification method of the present invention, hydrogen chloride contained in the condensed-phase stream is passed through the ion-exchange resin catalyst and reacted with trichlorosilane (SiHCl ₃ ) and silicon tetrachloride (SiCl ₄ ) by the following reaction formulas 1 and / And the effect of lowering the concentration of hydrogen chloride can be obtained. Further, by using the ion exchange resin catalyst, there is an additional effect of removing impurities contained in the condensed phase stream.

[Reaction Scheme 1]

[Reaction Scheme 2]

As described above, the condensed-phase stream containing the hydrogen chloride and the silane-based compound is passed through the ion-exchange resin catalyst to convert hydrogen chloride into trichlorosilane and / or silicon tetrachloride according to the above-mentioned Reaction 1 and / have.

More specifically, the above reaction can be performed by the following mechanism. First, the hydrogen chloride molecule forms an amine-hydrochloride or amine-chloride silane salt by the amine functionality of the ion exchange resin catalyst. Also, the Cl ^- ion of the amine-hydrochloride can attack the silicon atom of the trichlorosilane by acid-catalysis, resulting in the hydrogen atom dropping and silicon tetrachloride being formed.

According to an embodiment of the present invention, the condensed-phase stream introduced into the catalytic reactor comprises about 0.01 to about 5 mol% of hydrogen chloride, about 0.01 To about 1 mol%, and the balance of the chlorinated silane-based compound. On the other hand, for more effective removal of hydrogen chloride, the number of moles of trichlorosilane relative to 1 mole of hydrogen chloride (HCl) may be 1 mol or more.

The relative content of hydrogen chloride in the entire condensed phase stream may be reduced to about 80 to about 100 mole%, preferably about 90 to about 99.9 mole%, before passing through the catalytic reactor.

The step of passing the condensed phase stream through a catalytic reactor comprising the ion exchange resin catalyst is carried out at a temperature of from about 0 to about 100 < 0 > C and a pressure of from about 1 to about 30 bar, from about 1 to about 20 bar, But the present invention is not limited thereto, and the conditions can be appropriately changed within the range in which the ion exchange resin catalyst is activated.

According to an embodiment of the present invention, after passing through the catalytic reactor including the ion exchange resin catalyst, a separation process for separating the chlorosilane-based compound contained in the passed condensed-phase stream may be performed.

The separation step may be performed without any particular limitation as long as it is a method of separating a high boiling point compound and a low boiling point compound from a mixture, for example, by a distillation step, a separation membrane step, a gas-liquid separation step, or a combination thereof.

According to another embodiment of the present invention, there is provided a separation apparatus for separating off-gas discharged after a polysilicon deposition process by a chemical vapor deposition (CVD) process into a non-coherent phase stream and a condensed phase flow; And an ion exchange resin catalyst, and a catalytic reactor for removing hydrogen chloride from the condensed-phase stream.

At this time, the catalyst reactor including the ion exchange resin catalyst and the waste gas are as described above in the purification method.

The separation apparatus can be used without any particular limitation as long as it is a general apparatus capable of separating the high boiling point compound and the low boiling point compound from the mixture. For example, a knockout drum, a distillation apparatus, a separation membrane apparatus, . ≪ / RTI > In addition, the separator may be installed at a front end of the catalytic reactor, and may operate in different apparatuses and operating conditions depending on the object to be separated.

More specifically, according to one embodiment of the present invention, the waste gas discharged from the chemical vapor deposition reactor flows into the knock-out drum after cooling, and is supplied to the knock-out drum in an excess amount of hydrogen- Liquid phase condensate phase.

The non-condensing stream discharged from the top of the knock-out drum is injected into the absorption tower after the additional cooling and pressurization. The hydrogen contained in the non-condensing stream is discharged from the top of the absorption tower, have. In addition, the hydrogen chloride contained in the non-condensing stream is discharged to the lower portion of the absorption tower and is finally removed through the following catalytic reactor.

The liquid phase condensate stream discharged from the lower portion of the knockout drum is mixed with the liquid stream discharged from the absorption tower and injected into the catalyst reactor including the ion exchange resin catalyst. In the catalytic reactor comprising the ion exchange resin catalyst, hydrogen chloride is removed by the reaction of Reaction 1 and / or 2 described above, and the chlorinated silane based stream from which the hydrogen chloride has been removed is discharged.

According to another embodiment of the present invention, the waste gas discharged from the chemical vapor deposition reactor flows into the knock-out drum after cooling, so that the gaseous non-related-phase stream containing excess hydrogen and the liquid phase condensation containing an excessive amount of the chlorosilane- Phase flow.

The non-coherent stream of the vapor phase discharged from the top of the knock-out drum flows into the condenser and is cooled to a low temperature. Cryogenic cooling causes additional condensation of the hydrogen chloride and chlorosilane contained in the non-condensed stream of the gaseous phase, and the condensed stream is recycled back to the knock-out drum. Thereafter, the non-condensing stream is injected into the absorber, and the hydrogen contained in the non-condensation stream is discharged from the top of the absorber and can be finally purified and recycled at the adsorption tower. In addition, the hydrogen chloride contained in the non-condensing stream is discharged to the lower portion of the absorption tower and is finally removed through the following catalytic reactor.

The liquid phase condensed stream discharged from the lower portion of the knockout drum is mixed with the liquid stream discharged from the absorption tower and injected into the catalytic reactor including the ion exchange resin catalyst. In the catalytic reactor comprising the ion exchange resin catalyst, the hydrogen chloride is removed by the reaction of the above reaction formulas 1 and / or 2, and the chlorinated silane from which the hydrogen chloride is removed is discharged. Since the amount of hydrogen chloride and silane in the non-condensing stream is reduced due to the low-temperature cooling of the stream discharged from the upper part of the knock-out drum, the liquid-phase chlorinated silane recirculating stream transferred to the absorption tower can be reduced and operated. Is transferred to the secondary distillation column and is recycled after being separated into i / trichlorosilane and silicon tetrachloride.

Hereinafter, the purification apparatus of the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows an apparatus for purifying waste gas according to an embodiment of the present invention. Referring to FIG.

1, an apparatus for purifying exhaust gas according to an embodiment of the present invention includes a catalytic reactor 150, a knockout drum 115, an absorption tower 125, an adsorption tower 160, and a distillation tower 165 ).

The waste gas 101 discharged from the polysilicon deposition reactor 105 flows into the knockout drum 115 after cooling in the first cooler 110 and flows into the non-associated axial flow 102 containing excess hydrogen, Gt; 103 < / RTI > comprising an excess of the compound. The composition of the chlorinated silane-based compound in the non-conformal stream 102 may be determined by the temperature and pressure of the knock-off drum 115. The non-

The non-conforming stream 102 discharged from the top of the knock-out drum 115 is injected into the absorption tower 125 after additional cooling and pressurization in the second cooler 120, The hydrogen is discharged from the top of the absorption tower 125, and finally purified and recycled at the adsorption tower 160. The hydrogen chloride contained in the non-condensing stream 102 is discharged to the lower portion of the absorption tower 125 and is finally removed through the catalytic reactor 150, as described below.

The condensed stream 103 discharged from the lower portion of the knockout drum 115 is mixed with the liquid stream 106 discharged from the lower portion of the absorption tower 125 through the pump 170 and injected into the catalytic reactor 150. The stream in which the condensed phase stream 103 and the liquid stream 106 are mixed comprises about 0.01 to 1 mole percent of hydrogen, about 0.01 to about 5 mole percent of hydrogen chloride, about 0.01 to about 10 mole percent of a transition silanol, About 0.01 to about 80 mole percent trichlorosilane, and about 0.01 to about 50 mole percent silicon tetrachloride, but is not limited thereto.

The mixed stream of the condensed phase stream 103 and the liquid stream 106 passes through the catalytic reactor 150 filled with the ion exchange resin catalyst 155 and the hydrogen chloride in the catalytic reactor 150 reacts with the above- / RTI > can be converted to trichlorosilane and / or silicon tetrachloride according to < RTI ID = 0.0 > The catalytic reactor 150 may be operated at a temperature of about 0 ° C to about 100 ° C but is not limited thereto and may be changed within a range in which the ion exchange resin catalyst 155 is not inactivated.

The operating pressure also ranges from about 1 to about 30 bar, preferably from about 1 to about 20 bar, and more preferably from about 1 to about 10 bar, but the activity of the ion exchange resin catalyst 155 and the catalytic reactor 150 ) Within a range that does not affect the operation of the engine.

Unlike the conventional purification process including the distillation column instead of the catalytic reactor 150, the hydrogen chloride is converted into the chlorosilane compound in the above process, so that the gaseous hydrogen chloride is not discharged.

A part of the liquid chlorosilane-based stream 107 discharged from the lower part of the catalytic reactor 150 is transferred to the absorption tower 125 through the cooler 130 to absorb the hydrogen chloride and the chlorosilane compound in the non- And the remainder is conveyed to the distillation column 165. The chlorosilane-based stream 107 introduced into the distillation tower 165 is separated into gaseous disilicide silane and trichlorosilane and liquid silicon tetrachloride. The distillation column 165 can be operated at a pressure ranging from about 3 to about 7 bar and a temperature range between the dew point of silicon tetrachloride and the boiling point of the trichlorosilane. The dew point of silicon tetrachloride and the boiling point of the trichlorosilane can be controlled by operating pressure, As shown in FIG.

2 shows a purification apparatus for waste gas according to another embodiment of the present invention.

2, an apparatus 200 for purifying waste gas according to an embodiment of the present invention includes a catalyst reactor 250, a knockout drum 215, an absorption tower 225, and an adsorption tower 260 and a distillation tower 265 ).

The waste gas 201 discharged from the polysilicon deposition reactor is cooled by the first cooler 210 and then flows into the knock-out drum 215 to generate a non-smelting stream 202 containing excess hydrogen, Phase flow 203 which contains an excess amount of water. The composition of the chlorosilane-based compound in the non-condensing stream 202 may be determined according to the temperature and pressure of the knock-off drum 215. The flow rate of the non-

The non-condensing stream 202 discharged from the top of the knock-out drum 215 flows into the second cooler 220 and is cooled down to a low temperature. The cooling temperature may be in the range of about -30 to about -70 ° C, and more preferably in the range of about -40 to about -60 ° C. Cryogenic cooling results in additional condensation of the hydrogen chloride and chlorosilane contained in the non-condensing stream 202 and the condensed liquid stream is recycled back to the knock-out drum 215. The hydrogen chloride contained in the non-condensed stream 202 injected into the absorption tower 225 is discharged to the lower part of the absorption tower 225 and is finally removed through the following catalytic reactor 250. The hydrogen stream 204 discharged from the top of the absorption tower 225 is finally purified and recycled in the adsorption tower 260.

The condensed stream 203 discharged from the lower part of the knockout drum 215 is mixed with the liquid stream 206 discharged from the lower part of the absorption tower 225 through the pump 270 and injected into the catalytic reactor 250. The stream in which the condensed phase stream 203 and the liquid stream 206 are mixed comprises about 0.01 to about 1 mole percent hydrogen, about 0.01 to about 5 mole percent hydrogen chloride, about 0.01 to about 10 mole percent of a transition metal silane, About 0.01 to about 80 mole percent trichlorosilane, and about 0.01 to about 50 mole percent silicon tetrachloride, but is not limited thereto.

The mixed stream of the condensed phase stream 203 and the liquid stream 206 passes through the catalytic reactor 250 filled with the ion exchange resin catalyst 255 and the hydrogen chloride in the catalytic reactor 250 reacts with the above- / RTI > can be converted to trichlorosilane and / or silicon tetrachloride according to < RTI ID = 0.0 > The catalytic reactor 250 may be operated at a temperature of about 0 ° C. to about 100 ° C. However, the present invention is not limited thereto, and the catalytic reactor 250 can be changed within a range in which the ion-exchanging resin catalyst 255 is not inactivated.

The operating pressure also ranges from about 1 to about 30 bar, preferably from about 1 to about 20 bar, and more preferably from about 1 to about 10 bar, but the activity of the ion exchange resin catalyst 255 and the catalytic reactor 250 ) Within a range that does not affect the operation of the engine.

Unlike the conventional purification process including the distillation column instead of the catalytic reactor 250, the hydrogen chloride is converted into the chlorosilane compound in the above process, so that the gaseous hydrogen chloride is not discharged.

Part of the liquid chlorosilane-based stream 207 discharged from the lower portion of the catalytic reactor 250 is transferred to the absorption tower 225 and used for absorbing hydrogen chloride and chlorosilane-based compounds in the non-condensed stream. Since the amount of the hydrogen chloride and the silane based compound is significantly reduced by the additional cooling of the non-condensing stream 202 discharged from the top of the knockout drum 215 due to the second cooler 220, ) Can be reduced to a range of about 30 to 90%, and more preferably, it can be reduced to a range of about 50 to 80%.

The remaining stream is conveyed to the distillation column 265. The chlorosilane-based stream 207 flowing into the distillation column 265 is separated into gaseous disilicide silane and trichlorosilane and liquid silicon tetrachloride. The distillation column 265 can be operated in a pressure range of about 3 to about 7 bar and a temperature range between the dew point of silicon tetrachloride and the boiling point of the trichlorosilane. The dew point of silicon tetrachloride and the boiling point of the trichlorosilane As shown in FIG.

Best Mode for Carrying Out the Invention Hereinafter, the function and effect of the present invention will be described in more detail through specific examples of the present invention. It is to be understood, however, that these embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention.

< Example >

Preparation and performance evaluation of catalytic reactors

Manufacturing example  One

A catalytic reactor packed with an ion exchange resin catalyst was prepared and the performance of the catalytic reactor was evaluated by gas chromatography.

A styrene-divinylbenzene matrix type ion exchange resin catalyst (trade name: Amberlyst ^® A-21, Aldrich) having an amine functional group having a diameter of 490 to 690 μm in diameter was filled in a reactor of a 1/2 inch outer diameter tubular stainless steel . The amount of ethanol corresponding to three times the volume of the catalyst bed was separately flushed through the connected line for one hour and then flushed with the toluene amount corresponding to three times the volume of the catalyst bed for one hour to remove the impurities contained in the catalyst and The moisture was removed. Thereafter, final flushing was performed for one hour with an amount of silicon tetrachloride equal to three times the catalyst bed volume to remove any remaining solvent.

The trichlorosilane solution, in which hydrogen chloride was dissolved, was fed into the reactor at a level of about 10 ml per minute in the catalytic reactor which had been prepared for the reaction. The reactor temperature was maintained at 50 ° C and the pressure was maintained at 10 bar by pressurizing with hydrogen. The void volume of the catalyst bed was 65%, and the reaction residence time under the above conditions was 13.5 seconds. The composition of the trichlorosilane solution in which hydrogen chloride was dissolved was analyzed by gas chromatography through a by-pass line before the catalytic reaction, and it was confirmed that the composition contained about 2 mol% of hydrogen chloride relative to trichlorosilane. When the sum of the composition of the remaining gases except hydrogen was 100 mol%, it was confirmed that the hydrogen chloride was completely removed from the catalytic reactor by 94 mol% of 2 mol% trichlorosilane and 4 mol% of silicon tetrachloride.

Waste gas  Refining process Example

Example  One

The waste gas was purified using the purification apparatus shown in Fig.

A catalytic reactor (150) filled with an ion exchange resin catalyst (155) was prepared according to Preparation Example 1.

The temperature in the knockout drum 115 was set to -5 ° C., the pressure was set to 3 barG, the reaction temperature of the catalytic reactor 150 was set to 50 ° C., and the pressure was set to 11 barG.

The composition of the condensed stream flowing into the catalytic reactor 150 after passing through the knockout drum 115 is 2 mol% of hydrogen chloride, 9 mol% of dichlorosilane, 54 mol% of trichlorosilane, 34 mol% of silicon tetrachloride, 1 mol of hydrogen %.

As a result, it was confirmed that the composition of the stream discharged from the catalytic reactor 150 was 2% by mole of dichlorosilane, 67% by mole of trichlorosilane, 29% by mole of silicon tetrachloride and 2% by mole of hydrogen, Respectively.

Example  2

The waste gas was purified using the purification apparatus shown in Fig.

A catalytic reactor (250) filled with an ion exchange resin catalyst (255) was prepared according to Preparation Example 1.

The temperature in the knockout drum 215 was set to -5 ° C., the pressure was set to 3 barG, the reaction temperature of the catalytic reactor 250 was set to 50 ° C., and the pressure was set to 11 barG. The non-condensing stream discharged from the top of the knock-out drum 215 flows into the second cooler 220 and is once again condensed by the low-temperature cooling, and the condensed stream is recycled to the knock-out drum 215. The cryogenic cooling condition in the second cooler 220 was set at -40 DEG C and the pressure was set at 23 barG.

In the case where the second cooler 220 is not included in the non-condensing stream flowing into the absorber 225 after passing through the knockout drum 215 and the second cooler 220, 66% of hydrogen chloride, It was confirmed that 88% of the cyanide, 99% of the trichlorosilane and 97% of the silicon tetrachloride were reduced. Therefore, it was confirmed that the flow which is discharged from the lower part of the catalytic reactor 250 and recirculated to the absorption tower 225 is reduced by 56%, and the energy saving effect is about 10.3%.

The composition of the condensed stream flowing into the catalytic reactor 250 after passing through the knockout drum 215 was 2 mol% of hydrogen chloride, 9 mol% of dichlorosilane, 54 mol% of trichlorosilane, 34 mol% of silicon tetrachloride, 1 mol of hydrogen %.

As a result, it was confirmed that the composition of the stream discharged from the catalytic reactor 250 was 2% by mole of dichlorosilane, 67% by mole of trichlorosilane, 29% by mole of silicon tetrachloride and 2% by mole of hydrogen, Respectively.

100, 200, 300: Purification apparatus of waste gas
115, 215 315: Knockout drum
103, 203, 303: Condensation phase flow
102, 202, 302: non-associated axial flow
150, 250: catalytic reactor
125, 225, 325: absorption tower
160, 260, 355: adsorption tower

Claims (15)

Separating the off-gas discharged after performing the polysilicon deposition process by the chemical vapor deposition (CVD) reaction into the non-migratory phase stream and the condensed phase stream by the knock-out drum; And
And passing the condensed phase stream through a catalytic reactor comprising an ion exchange resin catalyst to convert hydrogen chloride to trichlorosilane and silicon tetrachloride to remove hydrogen chloride.
The ion exchange resin catalyst according to claim 1, wherein the ion exchange resin catalyst comprises a styrene-based polymer containing an amine group, a styrene-divinyl benzene-based polymer containing an amine group, &Lt; / RTI &gt;
The method of claim 1, wherein the waste gas comprises hydrogen chloride (HCl), hydrogen (H ₂ ), and a chlorosilane-based compound.
4. The method of claim 3, wherein the condensed phase stream comprises 0.01 to 5 mol% of hydrogen chloride, 0.01 to 1 mol% of hydrogen, and the balance of the chlorinated silane compound.
4. The method for purifying waste gases according to claim 3, wherein the chlorosilane compound comprises dichlorosilane (SiH ₂ Cl ₂ ), trichlorosilane (SiHCl ₃ ), and silicon tetrachloride (SiCl ₄ ).
The method of claim 1, wherein the amount of hydrogen chloride contained in the condensed-phase stream passed through the catalytic reactor is reduced by 80 mol% or more before passing through the catalytic reactor.
2. The method of claim 1, wherein the step of passing the condensed-phase stream through the catalytic reactor is performed at a temperature between 0 and 100 &lt; 0 &gt; C and 1 to 30 bar.
delete The method of claim 1, further comprising the step of passing the condensed phase stream through the catalytic reactor and then separating the chlorinated silane based compound contained in the passed condensed phase stream.
The method of claim 1, wherein the condensed-phase stream is passed through the absorber after mixing the non-co-axial stream separated by the knock-out drum with the liquid stream discharged and passed through the catalytic reactor.
A knock-out drum for separating the off-gas discharged after performing the polysilicon deposition process by the chemical vapor deposition (CVD) reaction into the non-associated axial flow and the condensed phase flow; And
An ion exchange resin catalyst comprising a styrene polymer containing an amine group, a styrene-divinyl benzene polymer containing an amine group, or a mixture thereof, And a catalytic reactor for removing hydrogen chloride from the condensed-phase stream.
delete delete 12. The apparatus of claim 11, further comprising a first cooler located at the front end of the knock-out drum and cooling the waste gas.
15. The apparatus of claim 14, further comprising a second cooler located downstream of the knock-out drum, further condensing the non-co-axial stream and recirculating the condensed liquid stream back to the knock-out drum.

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