Boiler feed water degassing membrane deoxygenization device

Abstract

The utility model discloses a degassing membrane deoxygenization device for boiler feed water. The degassing membrane deoxygenization device comprises a water distribution cavity, a front filter, a rear filter, a gas inlet pipeline, a gas outlet pipeline, a liquid inlet pipe, a liquid outlet pipe and a shell, one end of the water distribution cavity is connected with the front filter, and the other end is connected with the rear filter; the front filter is connected with a liquid inlet pipe, and the rear filter is connected with a liquid outlet pipe; a hollow fiber membrane module is arranged in the water distribution cavity, and the hollow fiber membrane module comprises hollow membrane filaments; one end of the hollow fiber membrane module is connected with the air inlet pipeline, and the other end is connected with the air outlet pipeline. The utility model has the beneficial effects that the manufacturing cost is low, the energy consumption is low, and the equipment configuration cost, the energy consumption cost and the later maintenance cost are greatly reduced; secondary pollution to water cannot be caused; the oxygen removal effect is excellent, and carbon dioxide can be removed while oxygen is removed; the equipment is small in size, light in weight and easy to arrange; automatic control can be realized; and the service life is long.

Description

Technical Field

[0001] The utility model relates to the field of boiler feed water deoxidation, in particular to a boiler feed water degassing membrane deoxidation device. Background Art

[0002] As a large industrial equipment that is difficult to install and replace, boilers need to be regularly maintained and cleaned to slow down their aging. Boiler water contains a certain amount of oxygen and carbon dioxide, which makes the boiler extremely susceptible to corrosion. The metal surface of the boiler is easily oxidized to metal oxides. At the same time, carbon dioxide will also cause the water to become acidic, accelerating the rate of metal corrosion. In addition, oxygen and carbon dioxide may also cause scale and sediment to form in the water, thereby clogging the pipes and increasing the energy consumption of the equipment, so the boiler feed water needs to be treated.

[0003] In the process of water treatment, deoxygenation is the most critical link. Current deoxygenation devices generally use thermal deoxygenation or chemical deoxygenation to remove oxygen dissolved in water. Among them, the thermal deoxygenation method consumes a lot of energy and requires a set of equipment, which is expensive.

[0004] The deoxygenation device of CN201510685267.3 includes an oxygen tower, a steam separator, a deoxygenation water tank, etc. The method of removing oxygen from water by regulating pressure and temperature requires a series of large-scale supporting equipment and consumes a lot of energy to keep it running. The chemical deoxygenation method of adding deoxygenators will bring harmful impurities into the boiler, causing secondary corrosion and pollution. Utility Model Content

[0005] 1. Problems to be solved

[0006] The technical problem to be solved by the utility model is to provide a boiler feed water degassing membrane deoxygenation device in view of the current status of the prior art.

[0007] (II) Technical solution

[0008] The utility model is realized through the following technical scheme: the utility model proposes a boiler feed water degassing membrane deoxygenation device: comprising a water distribution cavity, a front filter, a rear filter, an air inlet pipeline, an air outlet pipeline, a liquid inlet pipe, a liquid outlet pipe and an outer shell; one end of the water distribution cavity is connected to the front filter, and the other end is connected to the rear filter; the front filter is connected to the liquid inlet pipe, and the rear filter is connected to the liquid outlet pipe; a hollow fiber membrane module is arranged in the water distribution cavity, and the hollow fiber membrane module includes hollow membrane filaments; one end of the hollow fiber membrane module is connected to the air inlet pipeline, and the other end is connected to the air outlet pipeline; the outer shell plays a protective role; the air inlet pipeline and the air outlet pipeline are used to be connected to the gas treatment system to have the functions of vacuuming and passing purge gas.

[0009] By adopting the above technical solution, the microporous hydrophobic hollow membrane fibers made of polymer materials are placed in the water distribution cavity through which the liquid flows, thereby establishing a gas-liquid separation interface. After the liquid enters the water distribution cavity from the liquid inlet pipe, the hollow fiber membrane module is introduced with purge gas or vacuumed through the air inlet and outlet pipes. At this time, a corresponding gas concentration difference is generated between the inside and outside of the hollow membrane fibers. According to Henry's law and Dalton's law of partial pressure, such a difference in gas concentration can drive dissolved gases (oxygen, carbon dioxide, etc.) to be quickly and efficiently transmitted to the liquid flow, or removed from the liquid flow. Finally, the treated liquid is transported to the liquid storage tank through the liquid outlet pipe.

[0010] Furthermore, the hollow membrane fibers are hydrophobic hollow membrane fibers. The hollow membrane fibers are made of polypropylene, and polyolefins may also be used depending on the situation.

[0011] By adopting the above technical solution, countless nanoscale micropores exist on the surface of the hollow membrane filaments, and the characteristics of the material of the membrane filaments are utilized to establish a gas-liquid separation interface, so that the liquid will not penetrate into the hollow membrane filaments.

[0012] Furthermore, the water distribution cavity further includes a baffle, the cross-sectional area of ​​the baffle is smaller than the cross-sectional area of ​​the water distribution cavity; the baffle is provided with holes for the hollow fiber membrane module to pass through. The baffle is made of stainless steel, and carbon steel, alloy steel, nickel-based alloy, ceramic, plastic or polymer can also be used according to the situation.

[0013] By adopting the above technical solution, a baffle is set in the middle of the water distribution cavity, which can change the flow path and speed of the fluid in the device, thereby controlling the uniform distribution and mixing of the liquid. The baffle can make the liquid flow path more tortuous, preventing the liquid from flowing directly through the liquid outlet without degassing, so that the liquid can contact the hollow membrane more evenly and fully, thereby improving the deoxygenation effect. The baffle material can be made of different materials to meet the needs of different application scenarios.

[0014] Further, the front filter and the rear filter both include a filter element and a filter screen. The front filter and the rear filter both include a filter element and a filter screen. The material for making the filter element and the filter screen is stainless steel, and stainless steel, carbon steel, alloy steel and nickel-based alloy can also be used according to the situation.

[0015] By adopting the above technical solution, a front filter and a rear filter are respectively arranged at both ends of the water distribution cavity to remove impurities and improve water quality. The filter screen and the filter can be made of different materials to meet the needs of different application scenarios.

[0016] Furthermore, the liquid inlet pipe is connected to a security filter, the security filter is connected to a raw water pump, a water side valve is provided between the security filter and the raw water pump; the raw water pump is connected to the raw water tank. The liquid outlet pipe is connected to the deoxygenated water tank. The air inlet pipeline is connected to a gas side valve for introducing purge gas; the air outlet pipeline is connected to a vacuum pump, and the vacuum pump is used for vacuuming.

[0017] By adopting the above technical solution and connecting and cooperating these devices, the entire process of removing gas from boiler feed water can be completed, achieving a good boiler feed water deoxygenation effect.

[0018] (III) Beneficial effects

[0019] 1. The utility model can reduce the concentration of dissolved gas to a very low level by building a gas-liquid separation interface and adopting dissolved gas control technology. The deoxygenation effect is better than the traditional degassing process to achieve excellent deoxygenation effect. At the same time, the existing deaerator is generally only suitable for removing oxygen, but cannot solve the problem of carbon dioxide acidifying water quality and corroding equipment. The utility model removes a large amount of carbon dioxide dissolved in water while deoxygenating, so as to achieve a better boiler anti-oxidation corrosion effect.

[0020] 2. The existing deoxygenation methods have the following disadvantages: 1. Thermal deoxygenation requires a large amount of energy for deoxygenation; the equipment is large and will take up a large amount of space; the cost of configuring the equipment is high and the maintenance cost is also high. 2. Chemical deoxygenation is generally carried out by adding a deoxygenator to the water to remove oxygen from the water, and this method also causes secondary pollution of the water and corrosion to the device. In view of the shortcomings of the existing deoxygenation equipment, the utility model provides a boiler feed water degassing membrane deoxygenation device, which is low in cost, low in energy consumption, and will not cause secondary pollution to the water. In addition, the equipment is small in size and light in weight, and can be arranged at any position, which greatly saves infrastructure investment; it can be fully automatically controlled, and the device is suitable for long-term operation and has a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and the description thereof are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0022] Figure 1 It is a schematic diagram of the internal structure of a boiler feed water degassing membrane deoxygenation device described in the utility model;

[0023] Figure 2 This is a schematic diagram of the working structure of a boiler feed water degassing membrane deoxygenation device described in the utility model;

[0024] The reference numerals are as follows:

[0025] 1. Water distribution cavity; 2. Front filter; 3. Rear filter; 4. Air inlet pipe; 5. Air outlet pipe; 6. Liquid inlet pipe; 7. Liquid outlet pipe; 8. Housing; 9. Hollow fiber membrane module; 10. Hollow membrane filament; 11. Hydrophobic hollow membrane filament; 12. Baffle; 13. Filter element; 14. Filter screen; 15. Safety filter; 16. Raw water pump; 17. Water side valve; 18. Raw water tank; 19. Deoxygenated water tank; 20. Air side valve; 21. Vacuum pump. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] See also Figure 1-Figure 2 The utility model provides a technical solution: a boiler feed water degassing membrane deoxygenation device, comprising a water distribution cavity 1, a front filter 2, a rear filter 3, an air inlet pipeline 4, an air outlet pipeline 5, a liquid inlet pipe 6, a liquid outlet pipe 7 and a shell 8; one end of the water distribution cavity 1 is connected to the front filter 2, and the other end is connected to the rear filter 3; the front filter 2 is connected to the liquid inlet pipe 6, and the rear filter 3 is connected to the liquid outlet pipe 7; a hollow fiber membrane module 9 is arranged in the water distribution cavity 1, and the hollow fiber membrane module 9 includes a hollow membrane filament 10; one end of the hollow fiber membrane module 9 is connected to the air inlet pipeline 4, and the other end is connected to the air outlet pipeline 5; the shell 8 plays a protective role; the air inlet pipeline 4 and the air outlet pipeline 5 are used to be connected to the gas treatment system to have the functions of vacuuming and introducing purge gas.

[0028] Preferably, the hollow membrane fiber 10 is a hydrophobic hollow membrane fiber 11 .

[0029] Preferably, the hollow membrane fibers 10 may be made of polypropylene and / or polyolefin depending on the situation.

[0030] Preferably, the water distribution cavity 1 further comprises a baffle 12 , the cross-sectional area of ​​the baffle 12 is smaller than the cross-sectional area of ​​the water distribution cavity 1 ; the baffle 12 is provided with holes for the hollow fiber membrane module 9 to pass through.

[0031] Preferably, the material of the baffle 12 can be stainless steel, carbon steel, alloy steel, nickel-based alloy, ceramic, plastic or polymer according to the actual situation.

[0032] Preferably, the front filter 2 and the rear filter 3 both include a filter element 13 and a filter screen 14 .

[0033] Preferably, the material of the filter screen 14 can be stainless steel, carbon steel, alloy steel and nickel-based alloy according to the actual situation.

[0034] Preferably, the liquid inlet pipe 6 is connected to a safety filter 15 , the safety filter 15 is connected to a raw water pump 16 , a water side valve 17 is provided between the safety filter 15 and the raw water pump 16 ; the raw water pump 16 is connected to a raw water tank 18 .

[0035] Preferably, the liquid outlet is connected to the deoxygenated water tank 19 .

[0036] Preferably, the air inlet pipeline 4 is connected to a gas-side valve 20 for introducing a purge gas; the air outlet pipeline 5 is connected to a vacuum pump 21 for performing a vacuum operation.

[0037] The above technical solution achieves the degassing effect of boiler feed water through the following steps: first, the liquid in the raw water tank 18 is transported to the security filter 15 through the raw water pump 16 for the first filtration. A water side valve 17 is arranged between the raw water pump and the security filter 15 to control the fluid flow. After the first filtration of the security filter 15, the liquid is transported to the pre-filter 2 through the liquid inlet pipe 6 for the second filtration. The liquid after the second filtration comes into the water distribution cavity 1, and the liquid in the water distribution cavity 1 is fully in contact with the hollow membrane filament 10 in the hollow fiber membrane module 9 to form a gas-liquid separation interface. At this time, the vacuum pump 21 connected to the gas outlet pipeline 5 evacuates the hollow fiber membrane module 9 to change the gas concentration in the hollow membrane filament 10, so that the inside and outside of the hollow membrane filament 10 have a certain gas concentration difference. Because the membrane filament is made of hydrophobic material, the liquid will not penetrate into the membrane filament. There are nano-scale micropores distributed on the membrane filament. According to Henry's law and Dalton's law of partial pressure, the oxygen dissolved in the liquid is aggregated and precipitated by changing the total pressure of the gas phase. Then it is transferred to the inside of the hollow membrane filament 10 through the micropores, and then discharged from the device through the outlet pipe 5. The degassed liquid is transferred to the deoxygenated water tank 19 through the post filter 3 for storage for future use. If more gas needs to be dissolved in the liquid, nitrogen or other gases can be introduced into the hollow fiber membrane module 9 through the air inlet pipe 4, and the amount of gas introduced is controlled by the gas side valve 20; similarly, after the gas is dissolved in the liquid, it is transferred to the deoxygenated water tank 19 through the post filter 3 and the liquid outlet pipe 7 for storage for future use.

[0038] The design concept and effect of the utility model: the existing boiler feed water generally adopts thermal deoxygenation + chemical deoxygenation, which has high energy consumption. After deoxygenation, the water brings in impurities that are harmful to the boiler, causing secondary corrosion and pollution to the boiler. The deoxygenation effect is unstable and it is difficult to achieve the expected deoxygenation index. Through transformation, the deoxygenation method is changed to degassing membrane deoxygenation, and a two-stage degassing membrane deoxygenation method is adopted. The dissolved oxygen content can be reduced to below 7PPB, and the effect is stable and the energy consumption is low. The total power consumption of the entire degassing membrane deoxygenation device is only 5.5KW. The processing capacity of the device is 2 tons / hour, and the power consumption for 1 hour is about 5.5 degrees. 1 degree of electricity is calculated at 1 yuan, that is, the cost of deoxygenating 1 ton of boiler feed water is about 2.75 yuan, and the degassing membrane, the key component of the device, can have a service life of at least 5 years. It is maintenance-free at 0 cost during use, and the cost of use is very low. Compared with the prior art, the utility model operates at room temperature, does not need to consume steam, and greatly saves energy; it is a purely physical method, does not increase the salt content in the water, and does not have the problem of secondary pollution; the equipment is small in size and light in weight, and can be arranged at any position, which greatly saves infrastructure investment; the operating cost is low, and except for consuming a small amount of electricity, no other substances are consumed; oxygen and carbon dioxide in the water can be removed; it is fully automatically controlled, suitable for long-term operation, and is insensitive to drastic changes in load; it has a long service life, and the service life of the core component degassing membrane is at least 5 years; it is arranged at a low position, and there is no water pump cavitation problem, which greatly extends the life of the water pump and reduces the power consumption of the water pump; capacity expansion can be simply achieved through parallel degassing membrane components; it creates favorable conditions for full utilization of low-temperature waste heat of clean fuel boilers.

[0039] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A boiler feed water degassing membrane deoxygenation device, characterized in that: It includes a water distribution cavity, a front filter, a rear filter, an air inlet pipeline, an air outlet pipeline, a liquid inlet pipe, a liquid outlet pipe and an outer shell; one end of the water distribution cavity is connected to the front filter, and the other end is connected to the rear filter; the front filter is connected to the liquid inlet pipe, and the rear filter is connected to the liquid outlet pipe; a hollow fiber membrane module is arranged in the water distribution cavity, and the hollow fiber membrane module contains hollow membrane fibers; one end of the hollow fiber membrane module is connected to the air inlet pipeline, and the other end is connected to the air outlet pipeline; the outer shell plays a protective role; the air inlet pipeline and the air outlet pipeline are used to be connected to the gas treatment system to have the functions of vacuuming and passing purge gas.

2. A boiler feed water degassing membrane deoxygenation device according to claim 1, characterized in that: The hollow membrane fibers are hydrophobic hollow membrane fibers.

3. A boiler feed water degassing membrane deoxygenation device according to claim 1, characterized in that: The water distribution cavity further comprises a baffle, the cross-sectional area of ​​the baffle is smaller than the cross-sectional area of ​​the water distribution cavity; the baffle is provided with holes for the hollow fiber membrane module to pass through.

4. A boiler feed water degassing membrane deoxygenation device according to claim 1, characterized in that: The front filter and the rear filter both include a filter element and a filter screen.

5. A boiler feed water degassing membrane deoxygenation device according to claim 1, characterized in that: The liquid inlet pipe is connected to a safety filter, the safety filter is connected to a raw water pump, a water side valve is arranged between the safety filter and the raw water pump; the raw water pump is connected to a raw water tank.

6. A boiler feed water degassing membrane deoxygenation device according to claim 1, characterized in that: The liquid outlet pipe is connected with the deoxygenated water tank.

7. A boiler feed water degassing membrane deoxygenation device according to claim 1, characterized in that: The air inlet pipeline is connected to a gas side valve for introducing purge gas; the air outlet pipeline is connected to a vacuum pump for performing a vacuum operation.

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