TWI722956B - Pm2.5 control device designed by combining particle condensation growth and inertial impaction techniques - Google Patents

Abstract

The present invention provides a PM2.5 control device designed by combining particle condensation growth and inertial impaction techniques, which includes a particle condensation growth device and a wetted multi-nozzle inertial impactor. Particles in an aerogel stream will be grown to larger particle sizes in the particle condensation growth device, and then are collected on a wetted impaction plate and washed clean by injection water through the plate in the wetted multi-nozzle inertial impactor, thereby achieving the effects of low pressure drop, low processing cost and high collection efficiency.

Description

PM2.5 control equipment combining particle condensation growth and inertial impact technology

The present invention relates to a particle collection device.

In the semiconductor industry, the emission of submicron and fine particles generated by processing chambers or high-temperature scrubbers often cannot be properly treated, thus becoming a source of white smoke emissions. Existing particulate control devices include electrostatic precipitators, dust collection chambers, and vent scrubbers. These particulate control devices cannot be used to remove explosives, have a fire hazard, take up a lot of space, and have a large pressure loss. People are satisfied. Therefore, how to provide a simple particle control device that can avoid the aforementioned deficiencies is really contemplated by those skilled in the art.

The main purpose of the present invention is to provide a simple particle control device.

In order to achieve the above and other objectives, the present invention provides a PM2.5 control device that combines particle coagulation growth and inertial impact technology, which includes a particle coagulation growth device and a wet multi-nozzle inertial impactor; the particle coagulation growth device includes an aerosol Inlet, a steam inflow, a mixing chamber, a growth chamber and a mixed aerosol outflow, the aerosol inflow is connected to the mixing chamber and located upstream of the mixing chamber, and the steam inflow is in the mixing chamber The growth chamber is located downstream of the mixing chamber, and the mixed aerosol flow outlet is connected to the growth chamber and located downstream of the growth chamber; the wet multi-nozzle inertial impactor includes a mixed aerosol flow inlet, a preparation chamber, and a Nozzle plate, a water injection impingement plate, a gap between the nozzle plate and the water injection impingement plate, a wake cavity and a wake outlet, the mixed gas glue flow inlet is connected to the mixed gas glue flow outlet and the preparation The cavity is located upstream of the preparation cavity, the nozzle plate is arranged on the water injection impingement plate and between the preparation cavity and the water injection impingement plate, and the nozzle plate has a plurality of communication between the preparation cavity and the impingement cavity. The water injection impact plate has a particle impact surface, at least one water injection port formed on the particle impact surface, a water injection channel, a water collection well partially surrounding the particle impact surface, and a water collection well partially surrounding the water collection well The airflow channel and a water pumping channel connected to the water injection channel, the water pumping channel connected to the water collection well, the air channel connected between the gap and the wake cavity, and the wake outlet connected In the wake chamber; wherein, the aerosol flow inlet is for introducing an aerosol flow containing a plurality of particles, the steam inlet is for introducing a water vapor flow, and the mixing chamber is for the aerosol flow and all The water vapor stream is mixed into a mixed aerosol flow, the growth chamber is for supersaturated water vapor to condense on the surface of the particles to increase the particle size of the particles, and the nozzle plate is used to increase the mixed aerosol flow to the gap The particle impact surface is used to collect the particles impacting the particle impact surface due to inertia, and the water injection port is for injecting water on the particle impact surface to collect and wash the particles on the particle impact surface. The water collection well is used to collect the water injected from the water injection port to the particle impact surface, and the air flow channel is for the wake of the mixed gas glue stream after the particles are separated to flow to the wake cavity.

Through the above design, the particles in the aerogel flow will condense and grow into a larger particle size in the particle coagulation growth device, and then be collected by the water injection impact plate in the wet multi-nozzle inertial impactor, thereby achieving low pressure loss and low pressure loss. Effects of processing cost and high collection efficiency.

Please refer to Figures 1 to 3, which shows one of the embodiments of the PM2.5 control device (hereinafter referred to as the particle control device) designed for particle coagulation growth combined with inertial impact of the present invention, which includes a particle coagulation growth device 1 and A wet multi-nozzle inertial impactor 2. The particle control equipment can be used to remove particles in the gas. For example, it can be used to treat the waste gas generated in the semiconductor manufacturing process. It may contain but not limited to silicon dioxide and other particles. The particle size of these particles may be between 0.1-1 µm. The main source of white smoke emissions.

The particle coagulation growth device 1 includes an aerosol inlet 11, a steam inlet 12, a mixing chamber 13, a growth chamber 14 and a mixed aerosol outlet 15. The aerosol flow inlet 11 is connected to the mixing chamber 13 and located upstream of the mixing chamber 13 for introducing an aerosol stream containing particles (Aerosol stream). The steam inlet 12 is formed at the end of the steam flow duct 121. The inlet end of the steam flow duct 121 has a larger inner diameter, such as 5 mm, and the end has a smaller inner diameter, such as 1 mm, so that the introduced The steam flow can be sprayed into the mixing chamber 13 at a higher flow rate and form a turbulent flow. The turbulent steam flow can be mixed with the aerogel flow to form a mixed gas in the mixing chamber 13 with better mixing efficiency. Glue flow; The flow direction of the aerogel flow introduced into the mixing chamber 13 in the mixing chamber 13 is the same as the direction in which the water vapor flow is injected, but it can also be designed in the opposite direction to increase the mixing effect of the aerogel flow and the water vapor flow; The introduced aerosol flow is, for example, normal temperature, and the temperature of the water vapor flow is, for example, 100°C. After the two are mixed, the temperature of the mixed aerosol flow will drop, so that the mixed aerosol flow is in a supersaturated state.

The growth chamber 14 is located downstream of the mixing chamber 13. The supersaturated water vapor in the mixed aerosol flow can condense on the surface of the particles in the growth chamber 14 to increase the particle size. The mixed aerosol flow in the growth chamber 14 is essentially one axis Flow upwards L; when set, the particle control device of this embodiment can be set obliquely, for example, there is an angle of 25∘ with the horizontal plane, and the downstream side of the growth chamber 14 is higher than its upstream side. As a result, it condenses on The water on the cavity wall 141 of the growth cavity 14 will not flow to the downstream wet multi-nozzle impactor 2, and at least part of the water condensed on the cavity wall 141 of the growth cavity 14 can be discharged from the condensation water outlet 142 on the cavity wall 141. Wherein, the cavity wall 141 defines the growth cavity 14, and the condensate outlet 142 is located on the side of the cavity wall 141 with the lowest gravitational potential energy, for example, at the bottom of the side close to the ground after the particle control device is inclined. The mixed aerosol flow outlet 15 is connected to the growth cavity 14 and is located downstream of the growth cavity 14.

The wet multi-nozzle inertial impactor 2 includes a mixed gas glue inlet 21, a preparation chamber 22, a nozzle plate 23, a water injection impact plate 25, and a gap 24 between the nozzle plate and the water injection impact plate. , A wake cavity 26 and a wake outlet 27. The mixed gas glue flow inlet 21 is connected to the mixed gas glue flow outlet 15 and the preparation chamber 22 and is located upstream of the preparation chamber 22. An adapter ring/transfer can be provided between the mixed gas glue flow inlet 21 and the mixed gas glue flow outlet 15 Pipe and connect the two. The nozzle plate 23 is arranged on the water-injection impingement plate 25 and is located between the preparation cavity 22 and the gap 24. The height of the gap 24 is the distance between the nozzle plate 23 and the water-injection impingement plate 25 (or the distance from the jet to the impingement plate, jet -to-plate distance), usually small only half to several times (for example, 2 times) of the nozzle diameter, and the nozzle plate 23 has multiple nozzle holes 231. The smaller the diameter of the nozzle holes 231, the mixed aerosol flow The velocity of the aerosol sprayed to the gap 24 through the nozzle will be accelerated faster, which can increase the inertia of the particles so that the water injection impact plate 25 can collect smaller particles (or intercept smaller aerodynamic diameters), but it is easy to cause the pressure of the airflow. Conversely, the larger the aperture of the nozzle hole 231, the smaller the flow velocity of the mixed aerosol flow 24 through the nozzle to the gap 24, and the particle inertia is smaller. The water injection impact plate 25 can only collect larger particles, but The pressure loss is low.

The water injection impact plate 25 has a particle impact surface 251, a water injection port 252 formed on the particle impact surface 251, a water injection channel 253, a water collection well 254 partially surrounding the particle impact surface 251, and an airflow partially surrounding the water collection well 254 Channel 255 and a water drain channel 256. The particle impact surface 251 is used to collect particles impacted by inertia on the particle impact surface 251, and a filter paper made of, but not limited to, glass fiber can be placed on the particle impact surface 251. The water injection channel 253 is connected to the water injection port 252, so that the water injection port 252 can be used to inject water on the particle impact surface 251 to collect particles on the particle impact surface 251 and wash them away. In a possible embodiment, the particle impact surface 251 may be provided Filter paper (not shown). The setting of the filter paper can prevent the water from being blown away by the high-speed airflow and increase the efficiency of particle collection. The water collection well 254 is used to collect the water injection on the particle impact surface 251, and the collected water can be discharged from the water pumping channel 256; among them, the water injection impact plate 25 has a well wall 257 that defines the outer contour of the water collection well 254. The well wall 257 There is a top surface 2571 that is the same height as the particle impact surface 251, so as to avoid or at least greatly reduce the condensation of water vapor in the mixed aerosol flow on the inner edge of the well wall 257. The air flow channel 255 is connected between the impingement cavity 24 and the wake cavity 26, and allows the wake of the mixed aerosol flow after particle separation to flow to the wake cavity 26, and the wake outlet 27 is connected to the wake cavity 26, so that the The wake can leave the wet multi-nozzle inertial impactor 2.

In order to facilitate the adjustment of the intercepted aerodynamic diameter of the wet multi-nozzle inertial impactor 2, the wet multi-nozzle inertial impactor 2 may further include at least one height adjustment gasket 28 arranged between the nozzle plate 23 and the water injection impact plate 25 for Adjust the height of the gap 24 between the nozzle hole 231 and the particle impact surface 251 (or jet-to-plate distance). The height adjustment spacer 28 may be, for example, a thickness of 0.25-0.8 mm. When the height of the gap 24 is adjusted by setting a height adjustment gasket, the intercepted aerodynamic diameter of the wet multi-nozzle inertial impactor 2 can be adjusted by using a polytetrafluoroethylene gasket and/or a metal sheet with a thickness of about 0.1 mm. Adjust, usually the smaller the height, the smaller the intercepting aerodynamic diameter, but the height of the gap 24 should be maintained at more than half the diameter of the nozzle, otherwise it will significantly increase the air pressure loss.

In a particle collection efficiency test, a room-temperature aerosol stream containing sodium chloride particles with a particle size of 20-980 nm (mode diameter of 126.3 nm) was introduced into the aerosol inlet of the previous embodiment. A steam stream of 100 ℃ is introduced into the steam inlet to mix with the normal temperature aerosol stream. When the mass flow rate mixing ratio of the steam stream and the aerosol stream is 0.1 and 0.12 (steam stream: aerosol stream), the two conditions are tested respectively. , The aerodynamic intercept diameter (D _pa50 ) of the wet multi-nozzle inertial impactor is set to 1 µm, the diameter of the nozzle hole is 0.72 mm, and the distance from the nozzle hole to the particle impact surface is 0.72 mm (jet-to-plate distance, this When S/W=1), the results after the test are shown in Table 1 and Table 2.

Table I mixing ratio Quantity concentration collection efficiency (%) Weight concentration collection efficiency (%) 0.1 98.42 99.99 0.12 97.12 99.97

Table II Particle size (nm) Quantity concentration collection efficiency (%) Mixing ratio = 0.1 Mixing ratio = 0.12 47 97.70 97.60 103.7 97.47 96.70 148.6 99.30 97.40 245.8 99.60 97.50 406.8 99.30 97.60 504.8 99.80 98.00 626.4 99.70 96.90 964.7 100.00 97.20

It can be seen from the test results in Table 1 that when the mass mixing ratio of the steam flow and the aerogel flow is between 0.1-0.12, the particle collection efficiency can be expected to reach over 97% (quantity concentration collection efficiency) and nearly 100% (weight concentration) Collection efficiency). In addition, further analysis of the collection efficiency of the number and concentration of different particle sizes, it can also be found that the efficiency of sub-micron (less than 1 micron or 1000 nm) particles in the aerosol flow is higher than 96.9%, and the particles are still as small as 47 nm. With a collection efficiency of over 97%, it can be proved that in the particle control equipment provided by the present invention, even if the aerodynamic intercepting diameter of the wet multi-nozzle inertial impactor is as high as 1 µm, it is The collection efficiency of sub-micron small particles (diameter above 47 nm) is very high, and the control performance of the particles is very excellent. In addition, because the wet multi-nozzle inertial impactor has a pneumatic interception diameter of micrometers and a large nozzle hole diameter, when the mixing ratio is 0.1, the particle control equipment can collect sub-micron particles, and the working pressure loss is only 2840 Pa, which is quite low working pressure loss, and effectively reduces the power consumption of the pumping pump, and this further derives another advantage: the particle processing cost of the present invention is extremely low, and the cost analysis is shown in Table 3 below Show.

Table Three Calculation item 30 L/min 500 L/min 10000 L/min unit Trial calculation Electricity fee per watt 4.20 4.20 4.20 New Taiwan Dollar/W ＊Source: Taiwan Power Company Water charge per fair 9.45 9.45 9.45 New Taiwan Dollar/m ³ ＊Source: Taiwan Water Supply Company Pump electricity fee 0.19 3.10 61.94 New Taiwan Dollar Electricity fee for heater 15.24 253.99 5079.77 New Taiwan Dollar Water fee 0.06 0.81 16.01 New Taiwan Dollar Daily cost 15.49 257.9 5,157.72 New Taiwan Dollar Waste gas treatment fee per liter 0.00036 0.00036 0.00036 New Taiwan Dollar

It can be seen from the cost calculations in Table 3 that, because the present invention does not require high pressure loss, can achieve excellent particle removal efficiency with a low mixing ratio, and uses less water, the pump electricity and water costs are extremely low, and the processing costs are large. The source is the heater electricity fee required to generate water vapor, but even so, the treatment fee per liter of exhaust gas is still only NT$0.00036, which is a fairly cheap treatment cost. If the excess steam in the plant can be utilized, or the electricity bill of the heater can be reduced by recycling process waste heat or using renewable energy, the processing cost can be further reduced.

In another load test using the embodiment shown in Figures 1 to 3, four test groups were tested under the conditions shown in Table 4 below. The aerogel stream contained polydisperse titanium dioxide particles, where The flow rate of titanium dioxide particles introduced into the particle control device was 1.22 mg/min. Test groups one and two were subjected to a 25-minute load test, and test groups three and four were subjected to a 45-minute load test. The remaining test conditions of each test group were the same. After the test, the pressure loss of the particle control equipment before and after the test is compared, and the results are shown in Table 5. The particle collection efficiency of test groups 3 and 4 are also shown in Table 6.

Table Four Test group one Test group two Test group three Test group four Whether the water vapor stream is injected into the mixing chamber no no Yes Yes Water injection port flow (ml/min) 0 1.5 0 1.5

Table 5 Test group one Test group two Test group three Test group four Pressure loss increase rate before and after the test (%) 43 17 7.5 2.9

Table 6 Test elapsed time (min) Weight concentration collection efficiency (%) Test group three Test group four 5 99.82 99.13 10 99.93 99.93 15 99.66 99.87 20 99.40 99.97 25 99.93 99.86 35 99.87 99.91 45 99.97 99.98

According to the test results, the load test performance of test group 1 was found to be poor. After the test, multiple peak-shaped particles were observed at the particle impact surface facing the nozzle hole, and linear particles were observed around the nozzle hole. It can be seen from the test results in Table 5 that as long as the water vapor flow is introduced into the particle control device, regardless of whether the water injection port is filled with water, the pressure loss increase rate before and after the test can be greatly reduced; for example, test group 2 even if the water injection port is not filled with water , But after a 25-minute load test, the pressure loss increased by 17%; in contrast, after the 45-minute load test in test group three, the pressure loss only increased by 7.5%. The inventor found that this was because water vapor would condense on Particle surface, after impacting the particle impact surface, the condensed water can take the particles away from the particle impact surface, so that if the water injection port is not filled with water, the accumulation of particles on the particle impact surface is not obvious. It will significantly increase the pressure loss and maintain the particle removal efficiency similar to that of the test group 4. On the other hand, compared with test group three, test group four showed better long-term effectiveness. After a 45-minute load test, the pressure loss only increased by 2.9%, and the increase in pressure loss over time was not obvious. It is almost negligible, and after the test, no particle accumulation was observed around the particle impact surface and nozzle hole. This obviously overcomes the technical prejudice in this technical field. In the past, it was considered that the particle condensation growth technology was not suitable for the combined use of the inertial impact technology, because After the particles condense and grow, it will more easily cause the problem of clogging of the nozzle holes. However, experiments have shown that the combined use of particle coagulation growth technology and inertial impact technology can effectively remove the water and particles on the particle impact surface, and there will be no accumulation of particles and clogging of nozzle holes.

Please refer to FIG. 4, which is one of the embodiments of the particle control device of the present invention. The main difference from the previous embodiments is that more water injection ports 252 are formed on the surface of the particle impact surface 251, so that water injection, The flushing effect is more uniform, which is suitable for use occasions with large working flow.

In summary, the particles in the aerosol flow will condense and grow into a larger particle size in the particle coagulation growth device, and then be collected by the water injection impact plate in the wet multi-nozzle inertial impactor with a larger intercepted aerodynamic diameter. Washing off, thus achieving the effects of low pressure loss, low processing cost and high collection efficiency, it is a very excellent particle control equipment.

1: Particle Condensation Growth Device 11: Aerosol inlet 12: Steam inlet 121: Steam flow duct 13: Mixing cavity 14: Growing cavity 141: Cavity Wall 142: Condensate Outlet 15: Mixed aerosol outlet 2: Wet multi-nozzle inertial impactor 21: Mixed aerosol inlet 22: Preparation cavity 23: Nozzle plate 231: nozzle 24: gap 25: Water injection impact plate 251: Particle Impact Surface 252: Water Filling Port 253: Water Injection Channel 254: Catch Well 255: Airflow channel 256: Water Flow Path 257: Well Wall 2571: top surface 26: Wake cavity 27: Wake exit 28: height adjustment gasket L: axial

Figure 1 is a schematic longitudinal cross-sectional view of one of the embodiments of the present invention.

Figure 2 is an exploded view of a wet multi-nozzle inertial impactor according to one embodiment of the present invention.

FIG. 3 is a schematic top view of the water injection type impact plate of the wet multi-nozzle inertial impactor according to one embodiment of the present invention.

Fig. 4 is a schematic top view of a water-injection impact plate of a wet multi-nozzle inertial impactor according to another embodiment of the present invention.

1: Particle Condensation Growth Device

11: Aerosol inlet

12: Steam inlet

121: Steam flow duct

13: Mixing cavity

14: Growing cavity

141: Cavity Wall

142: Condensate Outlet

15: Mixed aerosol outlet

2: Wet multi-nozzle inertial impactor

21: Mixed aerosol inlet

22: Preparation cavity

23: Nozzle plate

231: nozzle

24: gap

25: Water injection impact plate

251: Particle Impact Surface

252: Water Filling Port

253: Water Injection Channel

254: Catch Well

255: Airflow channel

256: Water Flow Path

257: Well Wall

2571: top surface

26: Wake cavity

27: Wake exit

28: height adjustment gasket

L: axial

Claims (6)

A PM2.5 control device that combines particle condensation growth and inertial impact technology, including: A particle coagulation and growth device, comprising an aerosol inlet, a steam inlet, a mixing chamber, a growth chamber and a mixed aerosol outlet, the aerosol inlet communicating with the mixing chamber and located upstream of the mixing chamber, The steam inlet is located in the mixing cavity, the growth cavity is located downstream of the mixing cavity, and the mixed gas glue flow outlet is connected to the growth cavity and located downstream of the growth cavity; and A wet multi-nozzle inertial impactor, including a mixed gas glue inlet, a preparation chamber, a nozzle plate, a water injection impact plate, a gap between the nozzle plate and the water injection impact plate, and a wake Cavity and a wake outlet. The mixed gas glue flow inlet is connected to the mixed gas glue flow outlet and the preparation chamber and is located upstream of the preparation chamber. The nozzle plate is arranged on the water injection impingement plate and is located between the preparation chamber and the preparation chamber. The nozzle plate has a plurality of nozzle holes communicating between the preparation cavity and the impact cavity. The water injection impact plate has a particle impact surface and at least one particle impact surface formed on the particle impact surface. Nozzle, a water injection channel, a water collection well partially surrounding the particle impact surface, an air flow channel partially surrounding the water collection well, and a water pumping channel, the water injection channel is connected to the water injection channel, and the water pumping channel is connected to The water collection well, the impingement cavity is defined between the impingement plate and the particle impingement surface, the air flow channel is connected between the impingement cavity and the wake cavity, and the wake outlet is connected to the wake cavity; Wherein, the aerogel inlet is for introducing an aerosol stream containing a plurality of particles, the steam inlet is for introducing a water vapor stream, and the mixing chamber is for mixing the aerogel stream and the water vapor stream into one Mixed aerosol flow, the growth chamber is for condensing supersaturated water vapor on the surface of the particles to increase the particle size of the particles, and the nozzle plate is for increasing the velocity of the mixed aerosol flow to the impact chamber, and the particles impact The surface is for collecting the particles that impact the particle impact surface due to inertia. The water injection port is for injecting water on the particle impact surface to collect and wash off the particles on the particle impact surface. The water collection well is for collecting the particles. The water injection port injects water to the particle impact surface, and the air flow channel is used for the wake of the mixed aerosol flow after the particles are separated to flow to the wake cavity. The PM2.5 control device that combines particle condensation growth and inertial impact technology as described in claim 1, wherein the water injection impact plate further has a well wall defining the outer contour of the water collection well, and the well wall has an impact with the particles The top surface of the contour. The PM2.5 control device that combines particle condensation growth and inertial impact technology as described in claim 1, wherein the wet multi-nozzle inertial impactor further includes at least one height adjustment gasket disposed on the nozzle plate and the water injection impact plate Between to adjust the height of the gap. The PM2.5 control device combining particle condensation growth and inertial impact technology according to claim 1, wherein the particle condensation growth device further includes a cavity wall defining the growth cavity, and the cavity wall has a condensed water outlet. The PM2.5 control device that combines particle coagulation growth and inertial impact technology as described in claim 4, wherein the growth cavity further allows the mixed gas glue flow to flow substantially in an axial direction, and the axial direction of the growth cavity is not perpendicular to On the horizontal plane, the condensed water outlet is located on the side of the cavity wall with the lowest gravitational potential energy. The PM2.5 control device that combines particle condensation growth and inertial impact technology as described in claim 1, wherein the flow direction of the water vapor flow introduced into the steam inlet is the same as the flow direction of the aerogel flow in the mixing chamber, And the steam inlet is for the steam flow to be introduced into the mixing chamber in a turbulent state.

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