WO2020134515A1

WO2020134515A1 - Ozone gas dryer using concentrated sulfuric acid as drying agent

Info

Publication number: WO2020134515A1
Application number: PCT/CN2019/113984
Authority: WO
Inventors: 项义考
Original assignee: 项义考
Priority date: 2018-12-28
Filing date: 2019-10-29
Publication date: 2020-07-02
Also published as: CN109437112B; CN109437112A

Abstract

Provided is an ozone gas dryer using concentrated sulfuric acid as a drying agent, and comprising a pressure vessel and a gas-liquid mixer. The pressure vessel comprises a pressure barrel (1) and a top cover (2); the gas-liquid mixer comprises a cylinder body (3) provided inside the pressure barrel (1); an isolation plate (4) and a bottom plate (5) are respectively provided at an upper portion and a lower portion inside the cylinder body (3); multiple porous plates (6) are provided at an interior of the cylinder body between the isolation plate (4) and the bottom plate (5) in the manner of top and bottom intervals; through holes are formed in the isolation plate (4), the porous plates (6), and the bottom plate (5); a gas inlet pipe (7) is inserted in the through holes; a concentrated sulfuric acid feeding and discharging pipe (8) is inserted in the gas inlet pipe; a concentrated sulfuric acid feeding and discharging opening (10), a gas inlet (9), and a gas outlet (11) are formed in the top cover; the gas inlet pipe (7) is communicated with the gas inlet (9); an upper end of the concentrated sulfuric acid feeding and discharging pipe (8) is connected to the concentrated sulfuric acid feeding and discharging opening (10) in the top cover (2); a gas outlet pipe (13) is also provided on the isolation plate (4); and the gas outlet pipe (13) is connected to the gas outlet (11) in the top cover (2). According to the gas dryer, the concentrated sulfuric acid is used as the drying agent; gas and concentrated sulfuric acid are fully aerated and uniformly mixed in a gas-liquid mixing device; the contact area is increased; and most of water in the gas can be instantaneously absorbed.

Description

Ozone gas dryer using concentrated sulfuric acid as desiccant

Technical field:

The invention belongs to the technical field of high-concentration ozone production equipment, and particularly refers to an ozone gas dryer using concentrated sulfuric acid as a desiccant.

Background technique:

As we all know, ozone has an important use as a strong oxidant in many industries, especially after sterilization and oxidization of compounds, it does not leave any undesirable by-products by itself, and it has become the preferred oxidant for enterprises. However, the high cost of ozone production affects its popularization and application. When producing ozone, most enterprises choose air and oxygen enriched source of molecular sieve to produce ozone. The ozone concentration produced by the ozone machine is not only directly related to the oxygen concentration, but also closely related to the dryness of air or oxygen. For example, at a dew point temperature and dryness of -40℃, the ozone concentration is only 100g/m ³ , but at a dew point and dryness of -60℃, when oxygen passes through a certain ozone generator, it has the ability to make the oxygen in The ozone concentration is as high as 200g/m ³ , and the dew point temperature from -40℃ to -60℃, the ozone concentration can be doubled, which can reduce the power consumption and increase the oxidizing ability. The partial pressure of water vapor is only reduced from 12.9Pa to 1.08Pa. The partial pressure of vapor drops by 11.8Pa, and the amount of condensed water is not much, only half of the partial pressure drop of water vapor from -30℃ to -40℃, 38.1-12.9=25.2Pa, but the difficulty of dehydration increases, conventional compression and cooling , Silicone desiccant, molecular sieve oxygen machine drying, can not reach the dew point temperature of -60 ℃. This phenomenon has triggered many experts to tackle the problem, and some solid desiccants can reach a dew point temperature of -60 ℃, but face the problem of high dehydration costs.

Common solid desiccants include phosphorus pentoxide, magnesium perchlorate, potassium hydroxide, alumina, silica gel, calcium sulfate, magnesium oxide, magnesium bromide, sodium hydroxide, calcium oxide, calcium chloride, zinc chloride , Zinc bromide, copper sulfate, etc. According to existing knowledge, silica gel, calcium sulfate, magnesium oxide, magnesium bromide, sodium hydroxide, calcium oxide, calcium chloride, zinc chloride, zinc bromide, copper sulfate, etc. are dried The agents are not easy to be used as a desiccant at -60℃. Potassium hydroxide and alumina can be used as a desiccant at -60℃. However, it is not suitable for replacement with small capacity and frequent replacement. The more suitable solid desiccants are phosphorus pentoxide and magnesium perchlorate. Magnesium chlorate is very toxic and troublesome to regenerate. Phosphorus pentoxide absorbs water into phosphoric acid, which is non-renewable. There is a cost problem with large amounts of water absorption.

The common liquid desiccant is concentrated sulfuric acid, and concentrated sulfuric acid has the advantages of replacement, convenient heating and regeneration, and basically unchanged resistance after absorbing water. The disadvantage is that it has strong oxidation, strong acidity, strong corrosion, and weak volatile decomposition; With concentrated sulfuric acid as the desiccant, the gas component to be dried can only be neutral or acidic, and cannot react chemically with concentrated sulfuric acid. Therefore, commonly used dry gases include oxygen, nitrogen, hydrogen, carbon dioxide, inert gas, and some hydrocarbons When the gas is the gas used by the ozone machine to produce ozone, the effective component is oxygen, and the impurity gas components are nitrogen and carbon dioxide; the gas used by the ozone machine is in a flowing state instead of static, so when the gas is in contact with the liquid aeration It must be fully and evenly mixed, the contact area should be as large as possible, and it can absorb moisture in the gas instantaneously; the dew point temperature of 100% concentrated sulfuric acid can reach -68°C. Under aeration, there is the problem of volatilization of sulfur trioxide. Heating, the concentration of sulfuric acid can only be concentrated to 98%, and 98% concentrated sulfuric acid is difficult to reach the dew point temperature of -60 °C under normal pressure of 25 °C. Is it replaced with 100% concentrated sulfuric acid every time? Obviously does not work, under what conditions can 98% concentrated sulfuric acid be used as a water-absorbing desiccant at a dew point temperature of -60℃? The invention not only solves the problem theoretically, but also solves the problem on the specific structure of the dryer.

Summary of the invention:

The object of the present invention is to provide a gas dryer for ozone that can use concentrated sulfuric acid as a desiccant to instantly absorb moisture in the gas so that its dew point temperature reaches -60°C under normal pressure.

The present invention is implemented as follows:

An ozone gas dryer using concentrated sulfuric acid as a desiccant includes a pressure vessel and a gas-liquid mixer. The pressure vessel includes a pressure barrel and a top cover. The gas-liquid mixer includes a cylinder disposed in the pressure barrel , Separation plate and bottom plate are respectively arranged in the upper and lower parts of the cylinder body, the isolation plate divides the cylinder body into a recoil storage and a porous plate aeration mixer, and the isolation plate is provided with a communication recoil storage and a porous plate aeration mixing The air outlet of the device is provided with a number of porous plates spaced up and down in the porous plate aeration mixer, an exhaust hole communicating with the porous plate aeration mixer is provided at the lower part of the intake pipe, and a penetration plate is provided on the partition plate and the porous plate The inlet pipe is inserted in the through hole, the inlet and outlet of concentrated sulfuric acid are inserted in the inlet pipe, and the inlet, inlet and outlet of concentrated sulfuric acid, outlet, inlet and outlet of concentrated sulfuric acid are provided on the top cover. The air outlet is provided with a switch, the air inlet pipe is connected with the air inlet, the upper end of the concentrated sulfuric acid inlet and outlet pipe is connected to the concentrated sulfuric acid inlet and outlet on the top cover, the air outlet pipe is also provided on the isolation plate, the air outlet pipe and the top cover The air outlet is connected by a hose, and the barrel, porous plate, isolation plate, and bottom plate are made of corrosion-resistant materials.

In the above-mentioned ozone gas dryer using concentrated sulfuric acid as a desiccant, a partition tube is provided between adjacent porous plates, between the porous plate and the separation plate, and between the porous plate and the bottom plate, and the concentrated sulfuric acid inlet and outlet tubes The partition pipe is provided with an exhaust hole connecting the inner cavity of the intake pipe and the porous plate aeration mixer.

In the above-mentioned ozone gas dryer using concentrated sulfuric acid as a desiccant, a three-way connector is provided on the concentrated sulfuric acid inlet and outlet, one interface is the concentrated sulfuric acid inlet and outlet interface, the other interface is the motorized interface, and the other interface is the pressure measurement The port is also provided with a three-way connector on the motorized interface.

In the above-mentioned ozone gas dryer using concentrated sulfuric acid as the desiccant, the pore diameter of the holes on the perforated plate is 0.5-2mm, concentric rings are arranged, and the interval between the rings is 5-20mm, each ring The holes are set every 5-10mm, and the distance between adjacent porous plates is 100-200mm.

In the above-mentioned ozone gas dryer using concentrated sulfuric acid as the desiccant, the partition plate is fixedly connected to the cylinder, the air inlet pipe, and the air outlet pipe by welding, and the porous plate, the cylinder body, and the air inlet pipe pass through Fixed connection by welding or tight fitting connection.

In the above-mentioned gas dryer for ozone using concentrated sulfuric acid as a desiccant, the corrosion-resistant material is glass or PTFE or plastic.

In the above-mentioned ozone gas dryer using concentrated sulfuric acid as a desiccant, the bottom of the pressure barrel is provided with a vent, and a switch is provided on the vent.

In the above-mentioned gas dryer for ozone using concentrated sulfuric acid as a desiccant, the pressure vessel is made of carbon steel or stainless steel.

In the above-mentioned gas dryer for ozone using concentrated sulfuric acid as a desiccant, the pressure vessel is covered with heat insulation cotton.

In the above-mentioned gas dryer for ozone using concentrated sulfuric acid as a desiccant, a cold dryer is provided on the pipeline between the air inlet and the air compressor.

The outstanding advantages of the present invention compared to the prior art are:

The gas dryer of the present invention is an innovative gas dryer that combines a variety of container structures under theoretical guidance. It analyzes that concentrated sulfuric acid can be used as a gas desiccant for ozone based on the pressurization of an external air compressor and the cooling and cooling of a dryer. The design and manufacture of the gas dryer has five functions of "instant rapid water absorption, corrosion resistance, pressure resistance, two U-shaped anti-backlash structures, thermal insulation", oxygen and concentrated sulfuric acid in the aeration mixer The aeration is fully and uniformly mixed to expand the contact area, which can quickly and quickly absorb the water in the oxygen, and the oxygen is turned into a dry gas for the production of ozone.

BRIEF DESCRIPTION OF THE DRAWINGS:

Figure 1 is a schematic sectional view of the present invention;

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1;

3 is a top view of the top cover of the present invention.

In the picture: 1. Pressure barrel; 2. Top cover; 3. Cylinder body; 4. Isolation plate; 5. Bottom plate; 6. Perforated plate; 7. Air inlet pipe; 8. Concentrated sulfuric acid inlet and outlet pipe; 9. Air inlet; 10. Import and export of concentrated sulfuric acid; 11. Air outlet; 12. Switch; 13. Air outlet; 14. Hose; 15. Load-bearing ring; 16. Thermal insulation cotton; 17. Ventilation outlet; 18. Motorized interface; 19 1. Pressure measuring port; 20. Separator tube; 21. Fastening flange.

detailed description:

The following further describes the present invention with specific embodiments, see FIGS. 1-3:

An ozone gas dryer using concentrated sulfuric acid as a desiccant includes a pressure vessel and a gas-liquid mixer. The pressure vessel includes a pressure barrel 1 and a top cover 2. The gas-liquid mixer includes a pressure tank 1 The cylinder 3 is provided with an isolation plate 4 and a bottom plate 5 in the upper and lower parts of the cylinder 3 respectively. The isolation plate 4 divides the cylinder 3 into an upper recoil storage and a lower perforated plate aeration mixer to isolate The plate 4 is provided with air outlets connecting the recoil storage and the perforated plate aeration mixer. A number of perforated plates 6 are arranged up and down in the perforated plate aeration mixer, and through holes are provided in the isolation plate 4 and the perforated plate 6 , The intake pipe 7 is inserted in the through hole, the lower end of the intake pipe 7 is provided with an exhaust hole communicating with the porous plate aeration mixer, and the concentrated sulfuric acid inlet and outlet pipe 8 is inserted in the intake pipe 7 at the top The cover 2 is provided with an air inlet 9, a concentrated sulfuric acid inlet and outlet 10, an air outlet 11, the air outlet 11, the air inlet 9, the concentrated sulfuric acid inlet and outlet 10 are all opened and closed by a switch control 12, the air inlet pipe 7 and the air inlet 9 is connected, the upper end of the concentrated sulfuric acid inlet and outlet pipe 8 is connected to the concentrated sulfuric acid inlet and outlet 10 on the top cover 2, and an air outlet pipe 13 is also provided on the isolation plate 4, the air outlet pipe 13 is connected to the air outlet on the top cover 2 through the hose 14 11 connection, the cylinder 3, the porous plate 6, the separation plate 4, and the bottom plate 5 are made of corrosion-resistant materials.

The backflushing storage of the present invention communicates with the porous plate aeration mixer through the air inlet pipe 7 to form the first U-shaped anti-backflushing structure, which avoids possible leakage of concentrated sulfuric acid and is safe and reliable.

Specifically, the air inlet pipe 7 is provided in the middle of the partition plate 4, the air outlet pipe 13 is located on one side of the air inlet pipe 7, and the air outlet pipe 13 is fixedly connected to the partition board 4 by welding. The partition plate 4 is fixedly connected to the inner wall of the cylinder 3 by welding. The porous plate 6 is connected to the inner wall of the cylinder 3 and the intake pipe 7 in close contact or welding. A load-bearing ring 15 is welded to the bottom of the bottom plate 5 to adapt to the problem of uneven arcs on the bottom of the pressure tank 1. The thickening of the bottom plate can also be used to prevent the welding deformation and cracking of the bottom plate 5 and the barrel 3 due to weight.

In the present invention, 98% concentrated sulfuric acid is used as the initial desiccant. Oxygen and concentrated sulfuric acid are mixed in a gas dryer. The concentrated sulfuric acid absorbs the moisture in the oxygen, and the oxygen is turned into a dry gas for ozone production. Due to the strong corrosiveness of concentrated sulfuric acid, only acid-resistant corrosion-resistant materials such as polytetrafluoroethylene, plastic, and glass can be used as a container. Because concentrated sulfuric acid must achieve the required dehydration capacity under a certain pressure, polytetrafluoroethylene, plastic, Glass containers are not pressure-resistant, so pressure-resistant carbon steel or stainless steel shells are used as pressure vessels. Because carbon steel has special corrosion resistance to concentrated sulfuric acid, and carbon steel is cheaper than stainless steel, the pressure vessel is preferably made of carbon steel.

Similarly, considering that the liquid medium of the present invention is concentrated sulfuric acid, the water vapor in the gas is dissolved in the concentrated sulfuric acid, the concentrated sulfuric acid does not flow, only the gas flows, so the barrel 3 can be plastic, polytetrafluoroethylene, glass, titanium Corrosion-resistant materials such as plates; considering the cost and processing difficulty, the processing of plastic materials is the most convenient and the lowest cost; the processing difficulty of glass porous plates increases; the processing method of polytetrafluoroethylene porous plates is similar to that of plastics, but the cost increases; titanium The plate can take the form of punching but the cost is high. The material of the pressure barrel 1 and the perforated plate 6 may be corrosion-resistant materials such as glass, PTFE, plastic, etc. Taking the cylinder 1 and the perforated plate 6 as plastic PP materials as an example, for the problem of the aperture distance of the porous plate 6, the aperture 0.5-2mm, the hole distance is 6 times the hole diameter is within the range of adaptation, but affected by the specific gravity, viscosity and drilling method of concentrated sulfuric acid, the hole diameter is preferably 1mm; the hole distance is restricted by the hole drilling method, if modular heating die casting When arranged by mechanical punching of stainless steel plate, the hole distance is 2 times the aperture; if manual drilling is used, it is arranged in concentric rings, the rings are separated by 5-20mm, and the holes are punched every 5-10mm in the ring . If 0.5mm, 0.6mm, 0.7mm drills are used, the drills are easy to break during actual manual drilling, so 1mm drills are more suitable for drilling. The top of the cylinder 3 is sealed with only the gas outlet 11. After the gas and acid are mixed and aerated, the acid is left in the cylinder 3 as much as possible, and the gas is connected to the pressure vessel; the porous plate 6 is placed in the cylinder 3; porous The interval distance between the plates 6 is 100-200mm, which is more appropriate after the actual test. In the present invention, a partition tube 20 is provided between the isolation plate 4 and the porous plate 6 at the uppermost end, between the bottom plate 5 and the porous plate 6 at the lowermost end, and between the porous plate 6 and the porous plate 6 to avoid contact with the cylinder 3 The inner wall and the intake pipe 7 are in close contact with each other, and the porous plate 6 is loosely superimposed. Both the intake pipe 7 and the concentrated sulfuric acid inlet and outlet pipe 8 pass through the partition pipe 20. It can be known from the above data that the length of the partition tube 20 is 100-200 mm. Similarly, the partition pipe 20 is radially provided with an exhaust hole that communicates with the intake pipe 7 and the perforated plate aeration mixer.

Further, sulfuric acid is produced by dissolving sulfur trioxide in water. It is a non-volatile and stable inorganic acid under static and room temperature conditions. It is different from hydrochloric acid and nitric acid, but in aerated state, ≥25℃ The concentrated sulfuric acid will have more sulfur trioxide gas sulfuric acid mist escape. At this time, the aerated gas has a foul smell, especially when the gas is compressed by an air compressor, the gas temperature can reach 54°C, which is not suitable for ozone. Dry gas. Therefore, the concentrated sulfuric acid and gas must be cooled synchronously. The partial pressure of water vapor in the gas is more or less, which is directly related to the gas temperature. Therefore, cooling and cooling measures for compressed gas and concentrated sulfuric acid can not only reduce the volatile pollution of sulfur trioxide sulfuric acid mist, but also greatly reduce the amount of water vapor introduced, extend the use period of the desiccant, and make concentrated sulfuric acid as a desiccant. Convenient and practical. Therefore, in order to achieve simultaneous cooling and cooling of concentrated sulfuric acid and gas, a cold dryer is also provided on the pipeline between the air inlet 9 and the air compressor of the present invention. The cold dryer cools the pressurized gas, and the cooled pressurized gas can also cool concentrated sulfuric acid. The adjustment of pressure and temperature is controlled by external air compressor and cold dryer.

Further, carbon steel or stainless steel is also a good conductor of heat. When the external temperature is high in summer or other factors cause the ambient temperature to rise, it is easy to heat the pressurized gas after the dryer is cooled to the ambient temperature. The outer surface of the container is covered with thermal insulation cotton 16 to prevent the temperature of the acid and gas from rising, and reduce the volatilization of the acid and the partial pressure of water vapor of the gas. For example, the pressure vessel of this embodiment requires a carbon steel material with a pressure of 1.0 MPa, corrosion resistance to concentrated sulfuric acid, and a central cylindrical shape. After checking the sealing effect with the pressure resistance, wrap the thermal insulation cotton 16 on the outer surface of the pressure vessel 1, and then put on the outer packaging.

Of course, when concentrated sulfuric acid is in an aerated state, <25°C, it is not necessary to use a cold dryer and thermal insulation cotton.

Further, the pressure barrel 1 of the present invention is cylindrical, and the top cover 2 and the pressure barrel 1 are fixedly connected by a fastening flange 21. The bottom of the pressure barrel 1 of the present invention is further provided with a vent port 17, and a switch 12 is provided on the vent port 17.

In addition, the air inlet 9, the inlet and outlet 10 of concentrated sulfuric acid, and the air outlet 11 on the top cover 2 of the present invention are also fixedly connected to the top cover 2 through a flange. The flange includes two flange pieces, one of which is directly fixed On the top cover 2, the other flange has different parts. Corrosion-resistant switch is connected to the outside of the flange of the air inlet 9 and a corrosion-resistant short tube is connected to the inside to reduce or avoid contact of metal parts with concentrated sulfuric acid; the corrosion-resistant switch is connected to the outside of the flange of the air outlet 11 and the hose 14 is connected to the inside The pipe 14 is connected to the air outlet pipe 13 in the recoil storage, which facilitates the disassembly of the pressure tank 1 and the top cover 2; the inside of the flange of the concentrated sulfuric acid inlet and outlet 10 is connected to the concentrated sulfuric acid inlet and outlet pipe 8, and the outside of the flange is connected to the tee first, the interface One is a 10 port of concentrated sulfuric acid import and export, which is connected to a corrosion-resistant switch. One port is a switch 12 on the pressure measuring port 19, and a pressure gauge and a pressure safety valve are set on the switch 12. The other interface is connected to any switch on the tee of the motorized interface 18. During normal operation, the switch 12 of the concentrated sulfuric acid inlet and outlet 10 is closed, and one of the switches 12 connected to the motorized measuring port 18 is opened to maintain a pressure balance. Once the switch 12 of the concentrated sulfuric acid inlet and outlet 10 leaks, it can also prevent recoil leakage , Constitute the second U-shaped anti-backlash structure.

Further, a three-way joint is provided on the motorized interface 18, and two switches are provided. One switch is used for motorized measurement, negative pressure extraction of concentrated sulfuric acid, and motorized bleed; the other switch is connected to the concentrated sulfuric acid inlet and outlet flange outer three-way interface. Connection, when the switch is opened, the upper end of the concentrated sulfuric acid inlet and outlet pipe 8 and the recoil storage maintain pressure balance, then a second U-shaped anti-backlash structure is formed between the concentrated sulfuric acid inlet and outlet pipe 8 and the recoil reservoir. When opening the switch above the flange of concentrated sulfuric acid inlet and outlet 10 carefully, concentrated sulfuric acid will not be sprayed out, which is safe and reliable.

Analysis of the working principle of the present invention:

The invention provides a gas dryer for ozone with concentrated sulfuric acid as a desiccant, which produces ozone after drying the gas, and its working principle is analyzed as follows:

1. Analysis of the absorption and drying capacity of concentrated sulfuric acid

As we all know, concentrated sulfuric acid, phosphorus pentoxide, and magnesium perchlorate have extremely strong water absorption capacity. What specific data proves that they can reach a dew point temperature of ≤-60°C? According to known book data, the residual water weight in 1L of air at 101325 Pa at 1 atm and 25°C is 3×10 ^-3 mg for 100% concentrated sulfuric acid, 0.3 mg for 95% concentrated sulfuric acid, and 2×10 for phosphorus pentoxide ^-5 mg, magnesium perchlorate is 5×10 ^-4 mg.

The calculation results of phosphorus pentoxide, magnesium perchlorate and 95% concentrated sulfuric acid are shown in Table 1:

According to physics knowledge, at 0℃ water vapor gas, 1mol=18g=22.4L, then 3×10 ^-3 mg=3×10 ^-6 g=3÷18×10 ^-6 mol=3÷18×22.4× 10 ^-6 L=3.73×10 ^-6 L, 1L air is converted from 25℃ to 0℃, according to V1×T2=V2×T1, V ₀ ＝V ₂₅ ×273÷298＝0.916V ₂₅ ＝0.916L, then 25 The weight of water remaining in 1L of air at ℃, 100% concentrated sulfuric acid is 3×10 ^-3 mg, which is equivalent to the water vapor volume of 0°C is 3.73×0.916×10 ^-6 L=3.42×10 ^-6 L, which is equivalent to 3.42× 101325×10 ^-6 = 0.346Pa partial pressure of water vapor, which corresponds to a dew point temperature of -68°C.

It can be seen from Table 1 that the water absorption capacity of phosphorus pentoxide and anhydrous magnesium perchlorate powder is stronger than that of concentrated sulfuric acid and the dew point temperature is lower. In theory, phosphorus pentoxide and anhydrous magnesium perchlorate powder It is more suitable as a water-absorbing desiccant, but magnesium perchlorate powder is oxidizing and highly toxic, and it is dangerous and difficult to regenerate and replace by heating. Phosphorus pentoxide becomes phosphoric acid after water absorption, which is not renewable and has cost problems. Diphosphorus and anhydrous magnesium perchlorate powder are more suitable as trace moisture absorption desiccant. Liquid sulfuric acid replacement and dehydration regeneration are more convenient, so concentrated sulfuric acid is the main water absorption. Different concentrations of concentrated sulfuric acid have different water absorption capacity. Multi-stage series connection can achieve the required dryness. If concentrated sulfuric acid needs more dry gas after absorbing water, it is valuable to connect phosphorus pentoxide powder to further absorb water. However, 100% concentrated sulfuric acid can not be obtained by heating regeneration, generally 98% concentrated sulfuric acid, under normal pressure, there is a problem that the dew point is not easy to reach -60 ℃.

2. Increasing the pressure can reduce the dew point temperature and prevent the volatilization of acid gas

According to the data in Table 1, the dew point temperature of 100% concentrated sulfuric acid under normal pressure is -68℃, but the mass concentration of commonly used concentrated sulfuric acid is 98.3%, the density is 1.84g/cm ³ , the concentration is 18.4mol/L, and the boiling point is 338℃ , The dew point temperature of 95% sulfuric acid is only -31℃, heating regeneration cannot reach 100%, the highest concentration is 98.3%, using ≤98.3% concentrated sulfuric acid to absorb water, it is not easy to reach the dew point temperature of -60℃; in addition, when the concentration is 98.3% The sulfur trioxide is close to dynamic equilibrium. When concentrated sulfuric acid is aerated, a small amount of sulfur trioxide gas will escape to form acid mist. As a dry and clean gas for the ozone machine, it must not contain highly corrosive acid mist or acid gas.

Therefore, under normal pressure, concentrated sulfuric acid is not suitable as a gas desiccant for ozone at a dew point temperature of -60°C.

According to the relationship between the existing pressure and dew point temperature, the relationship between the dew point temperature and the normal atmospheric pressure dew point temperature at a pressure of 0.3-0.7MPa is shown in Table 2:

According to the data in Table 2, with the increase of air pressure, the gap between the pressure dew point temperature and the atmospheric dew point temperature continues to increase. For example, when the dew point temperature of 0MPa is -60℃, the pressure rises from 0.3MPa to 1.0MPa, and the dew point temperature difference Δt rises from 11℃ to 20 ℃, and so on; at the same pressure, the dew point temperature changes from low temperature to high temperature, and the gap between the pressure dew point temperature and atmospheric dew point temperature also continues to increase. For example, when 0.7 MPa, 0 MPa dew point temperature increases from -70 ℃ to 10 ℃, the dew point temperature The difference Δt rises from 15°C to 32°C. It can be seen that the pressure is better for dehydration of gas with higher temperature; when the pressure is 0.7MPa, the instrument measures about 98% sulfuric acid with a dew point temperature of -75°C. In addition, as the air pressure increases, the amount of sulfur trioxide decomposition and escape continues to decrease. When the pressure is 0.7MPa, the gas emitted by the aeration can be withstood by the nose.

The boost pressure can make 98% concentrated sulfuric acid reach the dew point temperature of -60 ℃, and can also eliminate the problem of sulfur trioxide volatilization, and meet the requirements of being a gas desiccant for ozone.

3. Cooling can reduce the dew point temperature, acid gas volatilization, and extend the service life

Sulfuric acid is produced by dissolving sulfur trioxide in water. It is a non-volatile and stable inorganic acid under static and room temperature conditions. It is different from hydrochloric acid and nitric acid, but under normal pressure and ≥25℃ aeration The dynamic equilibrium of the concentrated sulfuric acid is broken, and more sulfur trioxide gas will escape to form sulfuric acid mist. At this time, the aerated gas has a foul smell, especially when the gas is compressed by an air compressor, the gas temperature can reach 54°C and will be released. Produce more sulfur trioxide gas. Not only can the dew point temperature and sulfur trioxide volatilization be reduced by increasing the pressure, but the direct cooling can also be used to reduce the dew point temperature and sulfur trioxide volatilization, and it can also directly reduce the water vapor partial pressure.

According to the data of pressure, temperature and water vapor partial pressure Pa at 0MPa in Table 2, if there is only no pressure cooling device, at 0.7MPa, when the gas is compressed at 30℃ in summer, it rises to 54℃, the dew point temperature is 20℃, water The partial pressure of steam is 2339Pa. If the natural heat dissipation is reduced to 30℃, the dew point temperature is 0℃, and the partial pressure of water vapor is 610Pa. When the temperature is reduced to 18℃ after taking cooling measures, the dew point temperature is -10℃. The partial pressure is 260Pa. When the cooling temperature is reduced to 6℃, the dew point temperature is -20℃ and the partial pressure of water vapor is 102Pa. When the running time is the same, the difference between 54℃ and 6℃ compressed water vapor is about 23 times; natural cooling at 30℃ is about 6 times different than the cooling temperature of 6℃. Therefore, if the temperature is lowered or not at 30℃ in summer, the amount of water vapor introduced is at least about 6 times different. If it is unbearable to replace it once a month, then the desiccant can be accepted by the enterprise if it is replaced once every 6 months.

Therefore, cooling and cooling measures for compressed gas and concentrated sulfuric acid can not only reduce the volatile pollution of sulfur trioxide sulfuric acid mist, but also greatly reduce the dew point temperature, and can also reduce the amount of water vapor brought in, and extend the life cycle of the desiccant. Concentrated sulfuric acid becomes convenient and practical as a desiccant.

4. Application of U-tube anti-backlash principle

A single perforated plate aerator for dispersing bubbles in water can operate normally in the process of one-way gas flow with stable pressure, but during operation and pause, the flow in the opposite direction is often caused by pipeline leakage or other reasons, liquid When it is water, it is harmless to people and may cause damage to equipment. When the liquid is concentrated sulfuric acid, once it flows in the opposite direction, it will cause damage to people and equipment, resulting in accidents that should not occur. Concentrated sulfuric acid must not leak in both the forward and reverse flow directions. Many accidents occurred during the test, until the U-tube anti-backflushing principle was thought of, which was applied to the dryer, which can successfully solve the problem of backflushing corrosion and leakage, but not the two bottoms of the same diameter are connected in parallel at the bottom, but backflushing The storage and the aeration mixer are connected through an air inlet pipe to achieve the purpose of preventing backwash corrosion and leakage of concentrated sulfuric acid.

The concentrated sulfuric acid inlet and outlet, concentrated sulfuric acid inlet and outlet pipe, air intake pipe, recoil storage device and the concentrated sulfuric acid inlet and outlet and motorized outlet connecting switch of the invention form a U-shaped pipe anti-backlash structure.

During intake, concentrated sulfuric acid enters the aeration mixer. During recoil, concentrated sulfuric acid enters the recoil storage. The volume of the recoil storage is slightly larger than the volume of concentrated sulfuric acid after water absorption. Once the gas flows in the reverse direction, it will not leak out. There may be leakage accidents caused by the perforated plate aerator.

5. Use of corrosion-resistant and pressure-resistant containers

Due to the strong corrosiveness of concentrated sulfuric acid, the containers in contact with concentrated sulfuric acid can only be made of acid-resistant materials such as polytetrafluoroethylene, plastic, and glass as the container. Because concentrated sulfuric acid must reach the required water absorption capacity under a certain pressure, However, PTFE, plastic, and glass containers have poor compressive strength, which requires a pressure-resistant carbon steel or stainless steel shell to be used as a pressure-resistant container. Carbon steel has special corrosion resistance to concentrated sulfuric acid, and carbon steel is better than stainless steel. Cheap, so the shell is preferentially made of carbon steel.

6. Application of perforated plate aerator technology

Despite the measures of pressurizing and cooling the concentrated sulfuric acid and the use of corrosion-resistant and pressure-resistant containers, the purpose is to create conditions for the concentrated sulfuric acid to quickly absorb the moisture in the gas. The traditional aeration technology is not enough to absorb moisture quickly and efficiently. The invention patent technology of "a porous plate aerator for dispersing bubbles in water" can make up for the defect of uneven gas-liquid mixing. The ideas of the invention patent and the main manufacturing structure are cited to fully mix the concentrated sulfuric acid with the flowing gas aeration and expand the contact The area can absorb most of the moisture in the gas instantaneously to achieve the purpose of drying the gas. The porous plate oxygenation device is applied here, called the gas-liquid mixer, and is the core device of the gas dryer.

Analysis of water absorption regularity of seven concentrated sulfuric acid

According to the existing public data, collect the specific gravity and mol concentration of concentrated sulfuric acid at different concentrations, calculate the concentration of concentrated sulfuric acid for every 2% decrease, calculate the total weight after water absorption, get the total water absorption, 2% concentration difference increase in water absorption, summarize its Regularity, calculation results are shown in Table 3.

According to the data in Table 3, in the concentration range of 100%-88%, it was found that every time the concentration of concentrated sulfuric acid decreased by 2%, the weight of water increased slowly on the basis of 38.2 grams, the increase was between 1.6-2.1, but 88% and 86% absorbed water The difference is 9g, the inflection point appears suddenly, and 86% and 84% recovers. In general, the concentration of concentrated sulfuric acid changes linearly with the water absorption and dew point temperature. This rule is conducive to multiple dryers in series, and the gradient increases approximately on average. From 98%, it can be reduced to 88% concentration and then reheated, which is about 5 times longer than a single use time. If it is extended to 84%, the time is extended. About 8 times, it is also helpful to reduce the frequency of replacement, reduce the workload, and save the power consumption of regeneration. Combining the data in Table 2, under the appropriate ambient temperature, after the compressed air is cooled to room temperature, especially when the gas flow speed is fast, the cooling effect becomes poor, and the power consumption increases, the cold dryer can be disabled and directly enter the concentrated sulfuric acid dryer Absorb water to dry.

8. The proportional relationship between the elements of the dryer

According to the specific gas flow rate of the present invention, it is assumed that the gas flow rate through the ozone generator is 1m ³ /h, and the gas flow rate through the porous plate in the porous plate aeration mixer is 0.5m/s. The pore size of the porous plate is 1mm, which is roughly calculated The number of holes in the perforated plate, determine the diameter of the perforated plate according to the drilling rules, and then determine the diameter and length of the cylinder, and then select the diameter range and height of the pressure vessel. The calculation results of each part are as follows:

1. The number of holes in the perforated plate 6

The hole diameter 0.5-2mm is within the range of adaptation. Now let's take manual drilling as an example. Here we choose a hole diameter of 1mm, the area of one hole is 7.85×10 ^-7 m ² , and the effective cross-sectional area of the hole is 1÷3600÷0.5 =5.555×10 ^-4 m ² , the number of holes required on a perforated plate is 5.555×10 ^-4 m ² ÷7.85×10 ^-7 m ² =707.

2. Size of porous plate 2 and barrel 1

The aeration holes are arranged in a straight line and a circular ring arrangement. On a plastic board, when the circular hole arrangement is arranged, the hole spacing is perforated according to the rule of 5mm in circumference and 10mm in the interval of the rings. Starting from a 60mm diameter ring, the first The circle 3.14×60/5=37 takes 36, the second circle 3.14×80/5=50, the third circle 3.14×100/5=62.8 takes 60, and so on, and punches a hole with a diameter of 220mm, 3.14× 220/5=138, 136, 9 circles, 782 holes>707, meet the requirements, the side is 10mm above the hole, the diameter of the porous plate is at least 240mm, the existing specifications of the plastic tube are 250mm in diameter, the wall thickness is 4.5mm, and the inner diameter is 241mm. It just matches the diameter of the porous plate 240mm, that is, the garden tube uses a plastic tube with a diameter of 250mm and a wall thickness of 4.5mm;

You can also continue to drill holes until a hole with a diameter of 280mm, 3.14 × 280/5 = 176 holes, a total of 12 circles, 1268 holes, 10mm above the edge, then the diameter of the porous plate is at least 300mm, and the existing specifications of plastic tubes have a diameter 315mm, the wall thickness is 4.5mm, and the inner diameter is 306mm, then the diameter of the porous plate can be selected to match 305mm. That is, the perforated plate has a diameter of 305mm, and the cylinder uses a plastic tube with a diameter of 315mm and a wall thickness of 4.5mm. See table 4

3. Determination of pressure vessel diameter

The inner wall of the pressure vessel and the pressure tank is not an ideal circle. When the cylinder is embedded in the inner wall of the pressure tank, the porous plate and the cylinder cannot be in close contact, so the gas-liquid mixer must be placed independently in the pressure tank and left The inner diameter of the pressure barrel is generally larger than the outer diameter of the plastic cylinder by 20mm, which is convenient for the plastic cylinder to be placed in the pressure cylinder. When the outer diameter of the cylinder is 250mm, the outer diameter of the pressure barrel is 300mm, the outer diameter of the cylinder is 315mm, and the outer diameter of the pressure barrel is 350mm.

4. The volume ratio of recoil memory and porous plate aeration mixer

According to the test experience, the concentration of concentrated sulfuric acid should be 1/3 of the effective height of the aeration mixer barrel. The gas-liquid mixing height after aeration accounts for 2/3, and the remaining 1/3 height is the gas-liquid separation space. The height of the flushing storage, considering that 98% to 86% of concentrated sulfuric acid has a 17.4% volume increase after absorbing water, and also consider the safe height of shock and overflow during backflushing, accounting for 1.2 times the height of concentrated sulfuric acid. Therefore, if the effective height of the cylinder is 42, The height of the flush storage is 12, and the height of the aeration mixer is 30. In addition, the height occupied by the isolation plate, the porous plate and the bottom plate is the total length of the cylinder. The height of the pressure vessel is greater than the total length of the cylinder.

The above-mentioned embodiments are only one of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Therefore, any equivalent changes made according to the shape, structure, and principle of the present invention should be covered in the present invention. Within the scope of protection.

Claims

An ozone gas dryer using concentrated sulfuric acid as a desiccant, characterized in that it includes a pressure vessel and a gas-liquid mixer. The pressure vessel includes a pressure barrel (1) and a top cover (2). The gas-liquid mixture The device includes a barrel (3) arranged in a pressure barrel (1), and a partition plate (4) and a bottom plate (5) are respectively arranged in the upper and lower parts of the barrel (3). The body (3) is divided into a recoil storage and a perforated plate aeration mixer, and the isolation plate (4) is provided with an air outlet connecting the recoil storage and the perforated plate aeration mixer, and spaced up and down in the perforated plate aeration mixer A plurality of perforated plates (6) are provided, a vent hole communicating with the perforated plate aeration mixer is provided at the lower part of the intake pipe, a through hole is provided on the partition plate (4) and the perforated plate (6), and the intake pipe (7 ) Inserted into the through hole, inserted into the intake pipe (7) with a concentrated sulfuric acid inlet and outlet pipe (8), and provided with an air inlet (9), concentrated sulfuric acid inlet and outlet (10) on the top cover (2), The air outlet (11), the air inlet (9), the concentrated sulfuric acid inlet and outlet (10), and the air outlet (11) are all provided with a switch (12), and the air inlet pipe (7) communicates with the air inlet (9). The upper end of the sulfuric acid inlet and outlet pipe (8) is connected to the concentrated sulfuric acid inlet and outlet (10) on the top cover (2), and an air outlet pipe (13), a gas outlet pipe (13) and a top cover are also provided on the isolation plate (4) 2) The air outlet (9) on the upper side is connected by a hose (14). The cylinder (3), porous plate (6), isolation plate (4), and bottom plate (5) are all made of corrosion-resistant materials.
A gas dryer for ozone using concentrated sulfuric acid as a drying agent according to claim 1, characterized in that between adjacent porous plates (6), between porous plates (6) and isolation plates (4) , A partition tube (20) is provided between the porous plate (6) and the bottom plate (5), and the concentrated sulfuric acid inlet and outlet tube (8) is passed through the partition tube (20), and a communication inlet tube is provided on the partition tube (20) 7) The exhaust cavity of the aeration mixer of the inner cavity and the perforated plate.
A gas dryer for ozone using concentrated sulfuric acid as a desiccant according to claim 1, characterized in that: a three-way connector is provided on the concentrated sulfuric acid inlet and outlet (10), one interface is a concentrated sulfuric acid inlet and outlet interface, and the other One interface is a motorized interface (18), and another interface is a pressure measurement port (19).
A gas dryer for ozone using concentrated sulfuric acid as a desiccant according to claim 1, characterized in that the holes on the perforated plate (6) have a hole diameter of 0.5-2mm, arranged in concentric rings, and between the rings The interval is 5-20mm, the holes in each ring are set every 5-10mm, and the interval between adjacent porous plates (6) is 100-200mm.
A gas dryer for ozone using concentrated sulfuric acid as a desiccant according to any one of claims 1 to 4, characterized in that the partition plate (4), the cylinder (3), and the intake pipe (7) 1. The air outlet pipe (13) is fixedly connected by welding, and the porous plate (6), the cylinder (3), and the air inlet pipe (7) are all fixedly connected by welding or tight fitting connection.
A gas dryer for ozone using concentrated sulfuric acid as a desiccant according to any one of claims 1 to 4, wherein the corrosion-resistant material is glass or polytetrafluoroethylene or plastic.
A gas dryer for ozone using concentrated sulfuric acid as a drying agent according to claim 1, characterized in that: a vent port (17) is provided at the bottom of the pressure barrel (1), and the vent port (17) ) Is provided with a switch (12).
The ozone gas dryer using concentrated sulfuric acid as a drying agent according to claim 1, wherein the pressure vessel is made of carbon steel or stainless steel.
The ozone gas dryer using concentrated sulfuric acid as a drying agent according to claim 1 or 8, wherein the pressure vessel is covered with a thermal insulation cotton (16).
A gas dryer for ozone using concentrated sulfuric acid as a desiccant according to claim 1, characterized in that a cold dryer is provided on the pipeline between the air inlet (9) and the air compressor.