TW201603873A - Tail gas treatment system and tail gas treatment method - Google Patents

Abstract

A tail gas treatment system and tail gas treatment method comprise a washing device, a heat exchanger, and a wet pump. The washing device receives a tail gas containing an ammonia gas and absorbs and converts the ammonia gas within the tail gas into ammonia. The heat exchanger is connected to the washing device and receives the liquid ammonia and separates the gaseous state ammonia and low concentration ammonia from the ammonia gas-liquid. The wet pump is connected to the heat exchange equipment and uses negative pressure to draw gaseous state ammonia so as to be converted into high concentration liquid ammonia.

Description

Exhaust gas treatment system and tail gas treatment method

The invention relates to a gas treatment system and a gas treatment method, in particular to an exhaust gas treatment system and a treatment method of tail gas and ammonia water.

Ammonia in the semiconductor industry or optoelectronic industry, such as the Light Emitting Diode (LED) industry, is often used in a large number of procedures for etching, epitaxy or cleaning, in which only part of the ammonia will participate in the reaction, while the rest The reacted ammonia is directly discharged from the semiconductor device, and is discharged to the exhaust system at the rear end of the semiconductor process for exhaust gas treatment, thereby removing ammonia gas or other fine dust from the exhaust gas to comply with environmental regulations.

In addition, there are two types of tail gas treatment procedures for ammonia gas, which are generally acid absorption method and combustion method. The acid absorption method uses, for example, sulfuric acid or phosphoric acid as an adsorption medium, and converts the ammonia and the adsorption medium into an ammonium sulfate solution or an ammonium phosphate solution, and then discharges, but the acid absorption method cannot solve the problem. Further, combustion exhaust gas sucked through a burner, high temperature oxygen gas into lytic combustion emissions, however, there is such a combustion of nitrogen oxides (NO _X) emission concerns, high maintenance and operating costs is difficult to reduce the Disadvantages. Therefore, these methods are only a temporary solution and prevent ammonia from being recycled.

Therefore, the current problem in the semiconductor process for the tail gas treatment process containing ammonia gas is that, in addition to the complexity and length of the processing procedure, it must also cost a considerable amount of money to purchase and use high-purity ammonia and related processing equipment. The ammonia removed from the exhaust gas can no longer be recycled, which undoubtedly causes a significant increase in the cost associated with the semiconductor process.

In view of the above problems, the present invention provides an exhaust gas treatment system for solving the problem that conventional treatment lines or procedures for ammonia-containing exhaust gas are too complicated, lengthy, and ammonia gas cannot be recovered and reused after being removed from the exhaust gas.

The exhaust gas treatment system of the present invention is adapted to treat exhaust gas discharged from a semiconductor device containing ammonia gas and other impurities (e.g., N ₂ , H ₂ , CH ₄ ..., etc.).

The invention discloses an exhaust gas treatment system adapted to process exhaust gas discharged from a semiconductor device, the exhaust gas containing ammonia gas. The exhaust gas treatment system includes a water washing device, a heat exchange device, and a wet pump. The water washing device receives the exhaust gas and provides a washing liquid to contact the exhaust gas for absorbing and separating the ammonia gas to convert the ammonia gas into ammonia water. The heat exchange device is connected to the water washing device, the heat exchange device receives the ammonia water, and the gas-liquid separation ammonia water is gaseous ammonia and low concentration ammonia water. The wet pump is connected to the heat exchange device to pump gaseous ammonia at a negative pressure and convert it into a high concentration ammonia water.

In an embodiment of the invention, the heat exchange device further comprises a heat source, the wet pump pumps gaseous ammonia at a vacuum of less than 1 atmosphere, and the heat exchange device heats the ammonia water through the heat source.

In an embodiment of the invention, the method further comprises connecting to a storage tank of the wet pump, the storage tank receiving and storing the high concentration ammonia water.

In an embodiment of the invention, the invention further comprises a circulation tank connected to the wet pump, wherein the circulation tank supplies the absorption liquid to the wet pump for washing the gaseous ammonia, and the gaseous ammonia is fully contacted with the absorption liquid to be absorbed and converted into a high concentration. Ammonia water, wherein the absorption liquid circulates between the circulation tank and the wet pump; and the storage tank is connected to the circulation tank and receives and stores the high concentration ammonia water.

In an embodiment of the invention, the water washing device is a wet wall tower, a water mist absorber or a scrubbing tower.

In an embodiment of the invention, the wet pump is a water seal pump or a venturi.

In an embodiment of the invention, a purification device is further connected to the storage tank for purifying the high-concentration ammonia water into a high-purity liquid ammonia product.

In an embodiment of the invention, the purification device comprises a heat exchange device, a dry negative pressure device, an anion and a cation adsorber, a water eliminator, a wet wall tower, an ice water machine, a cooling and pressing device, a gas removal device or a finished tank.

Moreover, in order to achieve the above object, the present invention further provides an exhaust gas treatment method, which is suitable for processing exhaust gas discharged from a semiconductor device, and the exhaust gas contains ammonia gas, and the exhaust gas treatment method comprises: conveying exhaust gas to a water washing device; providing a washing liquid Receiving exhaust gas into the water washing device to absorb ammonia gas in the separated tail gas, and converting ammonia gas into ammonia water; transporting ammonia water into a heat exchange device; pumping to a negative pressure by a wet pump, and ammonia water in the heat exchange device Vaporization, and gas-liquid separation into gaseous ammonia and low-concentration ammonia; and pumping gaseous ammonia in a wet pump and converting it into high-concentration ammonia.

In an embodiment of the invention, when the negative pressure is greater than 30 Torr, the heat exchange device is further A heat source is provided to heat the ammonia water to a vaporization temperature.

In an embodiment of the invention, when the temperature of the ammonia water is 30 to 80 ° C, the negative pressure is greater than 30 torr.

In an embodiment of the invention, the method further comprises storing a high concentration of ammonia water in the storage tank.

In an embodiment of the invention, the invention further comprises supplying a absorbing liquid to the wet pump in a circulating tank for washing the gaseous ammonia, allowing the gaseous ammonia to be in sufficient contact with the absorbing liquid to be absorbed and converted into a high concentration ammonia water, and the absorbing liquid is in the circulation tank and the wet water. Circulating flow between pumps, high concentration of ammonia and stored in storage tanks.

In an embodiment of the invention, the method further comprises refluxing the low concentration ammonia water from the heat exchange device to the water washing device.

In an embodiment of the invention, the method further comprises the steps of: delivering a high concentration of ammonia water to a purification device; and purifying the high concentration ammonia water into a high purity liquid ammonia product by using a purification device.

The effect of the present invention is that the exhaust gas treatment system can remove the ammonia gas in the exhaust gas by the water washing device to reduce the ammonia content in the exhaust gas to meet the discharge standard. At the same time, the exhaust gas treatment system can convert the ammonia water formed in the water washing device into gaseous ammonia and low concentration ammonia water by the synergistic action of the heat exchange device and the wet pump, and then convert the gaseous ammonia into a high concentration by the wet pump. The finished ammonia water can be used to recycle ammonia that has no other function in the exhaust gas and is considered as exhaust gas. At the same time, the exhaust gas treatment system of the present invention greatly shortens the processing flow of the exhaust gas compared to the prior art, and further reduces the processing cost in addition to reducing the cost of the processing equipment.

The features, implementations, and utilities of the present invention are described in detail below with reference to the drawings.

10‧‧‧Exhaust gas treatment system

110‧‧‧Washing device

111‧‧‧Exhaust

112‧‧‧ Washing liquid

113‧‧‧Ammonia

120‧‧‧Heat exchange device

121‧‧‧Transport line

122‧‧‧Gaseous ammonia

123‧‧‧Low concentration ammonia

124‧‧‧heat source

130‧‧‧wet pump

150‧‧‧ storage tank

151‧‧‧High concentration ammonia

160‧‧‧Circular trough

161‧‧‧Inlet pipe

162‧‧‧Return line

163‧‧‧absorbing liquid

180‧‧‧purification equipment

181‧‧‧High-purity liquid ammonia finished product

Figure 1 is a schematic view showing the combination of an embodiment of the exhaust gas treatment system of the present invention.

Fig. 2 is a flow chart showing the exhaust gas treatment method of the embodiment shown in Fig. 1 of the present invention.

Figure 3 is a schematic view showing the combination of another embodiment of the exhaust gas treatment system of the present invention.

Fig. 4 is a flow chart showing the method of treating exhaust gas in the embodiment shown in Fig. 3 of the present invention.

Figure 5 is a schematic view showing the combination of another embodiment of the exhaust gas treatment system of the present invention.

Figure 6 is a flow chart showing the exhaust gas treatment method of the embodiment shown in Figure 5 of the present invention.

The exhaust gas treatment system of the present invention is applied in a semiconductor process, connected to an exhaust end of a semiconductor device, and receives and processes exhaust gas generated at a rear end of the semiconductor process from the exhaust end, the exhaust gas containing or used in a semiconductor process Ammonia (NH ₃ ) and other impurities (such as N ₂ , H ₂ , CH ₄ ..., etc.).

Referring to FIG. 1 , an exhaust gas treatment system 10 according to an embodiment of the present invention includes a water washing device 110 , a heat exchange device 120 , and a wet pump 130 . The heat exchange device 120 is connected to the water washing device 110 and the wet pump. 130 is connected to the heat exchange device 120, wherein the water washing device 110 may be, but is not limited to, a wet wall tower, a water mist absorber, a scrubber, etc., which absorbs gas in a water-washing manner, and the wet pump 130 may be but not Limited to water seal pumps or venturi tubes. In the present embodiment, the water washing device 110 is a washing tower, and the wet pump 130 is a venturi tube as an example.

Referring to Figures 1 and 2, in the application, the exhaust gas treatment system 10 is a process for treating the exhaust gas 111 in an environment in which the wet pump 130 generates a negative pressure (i.e., a vacuum of less than 1 atmosphere). First, the exhaust gas treatment system 10 is connected to the exhaust end (not shown) of the semiconductor device through the water washing device 110. Therefore, the exhaust gas 111 generated in the semiconductor process is first transported into the water washing device 110 via the pipeline (step S101). Next, a washing liquid 112 (for example, pure water) is supplied into the water washing device 110, and the washing liquid 112 is sufficiently contacted with the exhaust gas 111 in the form of a spray or a water film, so that the ammonia gas in the exhaust gas is adsorbed by the washing liquid 112 from the exhaust gas 111. The separation is performed and ammonia water 113 (NH ₄ OH) is formed (step S102), wherein the washing liquid 112 may be, but is not limited to, circulating in the water washing device 110. Next, the ammonia water 113 is sent to the heat exchange device 120 (step S103), and the environment of the negative pressure is generated by the wet pump 130, the ammonia water is vaporized in the heat exchange device 120, and the gas-liquid is separated into the gaseous ammonia 122 and the low concentration. The ammonia water 123 (step S104), wherein the low-concentration ammonia water 123 can be returned to the water washing device 110 via the transfer line 121 to be used as an absorbing liquid, and mixed with the ammonia water 113, and then sent back to the heat exchange device 120 for a gas-liquid separation process.

It should be noted that the vacuum degree of the negative pressure provided by the wet pump 130 is related to the temperature of the ammonia water 113 formed in the water washing device 110. For example, when the temperature of the ammonia water 113 is 30 to 80 ° C, the wet pump 130 provides The environment in which the degree of vacuum is greater than 30 torr (Torr, 1 atmosphere is equal to 760 Torr) allows the ammonia 113 to vaporize in the heat exchange unit 120. In the present invention, the degree of vacuum provided by the wet pump 130 can be adjusted by the temperature of the ammonia water 113, so that the ammonia water 113 is in the proper state. Vaporization occurs in an empty environment, and the numerical relationship between the two is not limited to the examples illustrated in the embodiment.

As described above, when the ammonia liquid 113 is separated into the gaseous ammonia 122 and the low concentration ammonia water 123, the gaseous ammonia 122 is pumped from the heat exchange device 120 by the wet pump 130, and the gaseous ammonia 122 is washed by the wet pump 130. The gaseous ammonia 122 is converted into a high concentration ammonia water 151 (step S105). The high concentration ammonia water 151 can then be selectively stored in the storage tank 150 (step S106).

Based on the above, the exhaust gas treatment system of the present invention provides a negative pressure environment through the wet pump 130, and the water washing device 110 and the wet pump 130 perform a water washing process on the exhaust gas 111 and the gaseous ammonia 122, which can efficiently remove ammonia gas from the exhaust gas 111. In addition, the process of the exhaust gas 111 can be simplified, and the removed ammonia gas can be further converted into high-concentration ammonia water 151 for recycling.

Referring to FIG. 3 and FIG. 4, the difference between the embodiment disclosed in FIGS. 3 and 4 and the embodiment of FIGS. 1 and 2 is that the exhaust gas treatment system 10 disclosed in FIGS. 3 and 4 further includes a cycle. The tank 160 is connected between the wet pump 130 and the storage tank 150. The circulation tank 160 is connected to the wet pump 130 by the water inlet pipe 161 and the return pipe 162, respectively. The circulation tank 160 supplies an absorption liquid 163 (pure water or subsequently formed ammonia water) to the wet pump 130 via the return line 162 for washing the gaseous ammonia 122, and the gaseous ammonia 122 is sufficiently contacted with the absorption liquid 163 to be absorbed and transformed. It is ammonia water and/or high-concentration ammonia water 151, wherein the absorption liquid 163 is circulated between the circulation tank 160 and the wet pump 130 by using the water inlet pipe 161 and the return pipe 162 (step S401), and when the absorption liquid 163 reaches the demand When the concentration of the high-concentration ammonia water 151 is finished, the high-concentration ammonia water 151 product is collected in the storage tank 150 via a pipeline (step S106).

It should be noted that the ammonia water 113 is vaporized in the heat exchange device 120, and the gas and liquid are separated into gaseous ammonia 122 and low concentration ammonia water 123. The low concentration ammonia water 123 is further introduced into the water washing device 110 as the washing liquid 112 to absorb the exhaust gas 111. Ammonia flows in a closed environment, thus avoiding wastewater discharge.

Referring to FIG. 5 and FIG. 6 , the embodiment disclosed in FIGS. 5 and 6 is substantially the same as the embodiment of FIGS. 3 and 4 , and the difference between the two is the exhaust gas treatment system disclosed in FIGS. 5 and 6 . The 10 further includes a purification device 180 coupled to the storage tank 150. The high-concentration ammonia water 151 collected in the storage tank 150 can be directly used as a liquid ammonia product, or can be sent to the purification device 180 for purification treatment, thereby being used by a system equipment of a semiconductor factory, wherein the purification device 180 includes a heat exchange device, dry type Negative pressure device, anion and cation adsorber, water eliminator, wet wall tower, ice water machine, cooling and pressing device, gas removal device or finished tank. Thus, when a high concentration of ammonia 151 transported from the reservoir 150 to the purification device 180, via gasification, in addition to water purification device 180, anion and cation removal, cooling and removing the hetero pressurized liquefied gas (e.g. H _2, N ₂ After the purification process, the high-concentration ammonia 151 is purified into a high-purity ammonia ammonia product 181 of 6N or more (step S601), and the finished product can be introduced into the gas supply system of the semiconductor factory, and supplied to the related equipment, for example, for supplying the LED. It is used in the Metal-Organic Chemical Vapor Deposition (MOCVD) machine.

It should be noted that, in the embodiment disclosed in FIGS. 5 and 6, the step circulation groove 160 and the step S401 may be omitted, that is, as shown in the first and second figures, the storage tank 150 is connected to the wet pump 130. And the gaseous ammonia 122 is washed by the wet pump 130 to convert the gaseous ammonia 122 into the high-concentration ammonia 151 (step S105). The high concentration ammonia water 151 can then be selectively stored in the storage tank 150 (step S106). This is a person of ordinary skill in the art, and after fully understanding the embodiments of the present invention, it can be directly and without any knowledge, and therefore will not be further described herein.

Based on the above, in the embodiment disclosed in the third to sixth embodiments of the present invention, the combination of the wet pump 130, the circulation tank 160, and the storage tank 150 is a completely closed regeneration system, which can effectively prevent ammonia emissions and solve the problem. Ammonia nitrogen emissions from semiconductor or photovoltaic power plants.

At the same time, the exhaust gas treatment system and method of the present invention can greatly reduce the cost of exhaust gas treatment and the procurement cost of high purity ammonia.

Although the embodiments of the present invention are disclosed above, it is not intended to limit the present invention, and those skilled in the art, regardless of the spirit and scope of the present invention, the shapes, structures, and features described in the scope of the present application. And the number of modifications may be made, and the scope of patent protection of the present invention shall be determined by the scope of the patent application attached to the specification.

10‧‧‧Exhaust gas treatment system

110‧‧‧Washing device

111‧‧‧Exhaust

112‧‧‧ Washing liquid

113‧‧‧Ammonia

120‧‧‧Heat exchange device

121‧‧‧Transport line

122‧‧‧Gaseous ammonia

123‧‧‧Low concentration ammonia

124‧‧‧heat source

130‧‧‧wet pump

150‧‧‧ storage tank

151‧‧‧High concentration ammonia

Claims (15)

An exhaust gas treatment system is adapted to process an exhaust gas containing an ammonia gas, the exhaust gas treatment system comprising: a water washing device, receiving the exhaust gas, and providing a washing liquid to contact the exhaust gas, the washing liquid absorbing or separating the ammonia gas And converting the ammonia gas into an ammonia water; a heat exchange device connected to the water washing device to receive the ammonia water, and separating the ammonia water into a gaseous ammonia and a low concentration ammonia water; and a wet pump connected to the The heat exchange device pumps the gaseous ammonia at a negative pressure and converts it into a high concentration ammonia water. The exhaust gas treatment system of claim 1, wherein the heat exchange device further comprises a heat source that pumps the gaseous ammonia at a vacuum of less than 1 atmosphere, and the heat exchange device transmits the heat source to heat the ammonia water. The exhaust gas treatment system of claim 1, further comprising a storage tank connected to the wet pump, the storage tank receiving and storing the high concentration ammonia water. The exhaust gas treatment system of claim 1, further comprising: a circulation tank connected to the wet pump, the circulation tank supplying an absorption liquid to the wet pump for washing the gaseous ammonia to make the gaseous ammonia Fully contacting with the absorbing liquid to be absorbed and converted into the high concentration ammonia water, wherein the absorbing liquid circulates between the circulation tank and the wet pump; and a storage tank connected to the circulation tank, and receiving and storing the absorbing liquid High concentration of ammonia. The exhaust gas treatment system of any one of claims 1 to 4, wherein the water washing device is a wet wall tower, a water mist absorber or a scrubber. The exhaust gas treatment system of any one of claims 1 to 4, wherein the wet pump is a water Seal the pump or a venturi. The exhaust gas treatment system of claim 3 or 4 further comprising a purification device coupled to the storage tank for purifying the high concentration ammonia water into a high purity liquid ammonia product. The exhaust gas treatment system of claim 7, wherein the purification device comprises a heat exchange device, a dry negative pressure device, an anion and cation adsorber, a water eliminator, a wet wall tower, a chiller, and a Cooling pressurizing device, a gas removal device or a finished tank. An exhaust gas treatment method, which is suitable for treating an exhaust gas containing an ammonia gas, the tail gas treatment method comprises: conveying the exhaust gas to a water washing device; providing a washing liquid to the water washing device to contact the exhaust gas to absorb and separate the exhaust gas Ammonia gas, and converting the ammonia gas into an ammonia water; conveying the ammonia water to a heat exchange device; pumping to a negative pressure by a wet pump, the ammonia water is vaporized in the heat exchange device, and the gas-liquid separation It is a gaseous ammonia and a low concentration ammonia water; and the gaseous ammonia is pumped by the wet pump and converted into a high concentration ammonia water. The exhaust gas treatment method of claim 9, wherein when the negative pressure is greater than 30 Torr, the heat exchange device further provides a heat source to heat the ammonia water to a vaporization temperature. The exhaust gas treatment method according to claim 9, wherein when the temperature of the ammonia water is 30 to 80 ° C, the negative pressure is greater than 30 Torr. The method for treating exhaust gas according to claim 9, further comprising storing the high concentration ammonia water in a storage tank. The method for treating exhaust gas according to claim 9, further comprising supplying an absorption liquid to the circulation tank to the a wet pump for washing the gaseous ammonia, the gaseous ammonia is sufficiently contacted with the absorption liquid to be absorbed and converted into the high concentration ammonia water, and the absorption liquid circulates between the circulation tank and the wet pump, and causes The high concentration ammonia water is stored in a storage tank. The tail gas treatment method according to any one of claims 9 to 13, further comprising refluxing the low concentration ammonia water from the heat exchange device to the water washing device. The exhaust gas treatment method according to any one of claims 9 to 13, further comprising the steps of: delivering the high concentration ammonia water to a purification device; and purifying the high concentration ammonia water into a high purity liquid ammonia product by the purification device .