CN203999136U - External loop airlift vortex enhanced biological nitrogen removal reactor - Google Patents

Abstract

The utility model discloses an airlift type external circulation vortex enhanced biological denitrification reactor, which is characterized in that it includes a water distribution section, a reaction section and a separation section, the water distribution section includes a lower short cylinder, and the cylinder is equipped with a There are water distributors and microporous aeration discs, the water distributors are connected to the water inlet pipes, and the microporous aeration discs are connected to the intake pipes; the reaction section includes a long cylinder, which is equipped with multi-stage Venturi tubes and multi-stage Venturi tubes. The two ends of the tube and the port of the long cylinder respectively form a diversion area and a mixing area, which are connected through the left and right circulation pipes to form a circulation; the separation section includes an upper short cylinder, and a water and air outlet system is installed in the cylinder. The utility model forms a vortex flow field in the multi-stage Venturi tube through the setting of the microporous aeration disc, the mixing zone and the multi-stage Venturi tube, which effectively enhances the mass transfer efficiency between the gas-liquid-solid three-phase; in addition, the above structure and The diversion area and the left and right circulation pipes are combined to form an external circulation, forming an aerobic-anoxic alternating environment, so that the reactor has the function of nitrification and denitrification biological denitrification.

Description

Air-lift external circulation vortex enhanced biological denitrification reactor

technical field

The utility model relates to a biological denitrification reactor for wastewater treatment, in particular to an air-lift type external circulation vortex enhanced biological denitrification reactor.

Background technique

my country's water pollution problem is very serious. Nitrogen continues to enter the water body with sewage, which can cause eutrophication of the water body, cause excessive growth of aquatic plants and algae, and derive a series of adverse consequences such as "water blooms" and "red tides". The economic loss caused by this is as high as tens of billions of yuan every year. It can be seen that it is imperative to develop a high-efficiency denitrification bioreactor.

Biological denitrification is generally divided into two stages, namely the nitrification stage and the denitrification stage. Under aerobic conditions, ammonia oxidizing bacteria and nitrite oxidizing bacteria in nitrifying bacteria undergo biological nitrification, ammonia oxidizing bacteria oxidize NH ₃ -N in wastewater to NO ₂ ^- , nitrite oxidizing bacteria convert NO ₂ ^- Oxidation to NO ₃ ^- ; under anoxic conditions, denitrifying bacteria reduce NO ₃ ^- to N ₂ , and N ₂ escapes from the liquid phase to achieve biological denitrification.

In recent years, three-phase fluidized bed bioreactors represented by air-lift internal circulation denitrification reactors have emerged in the fields of biochemical industry and wastewater treatment. Circulating flow can form aerobic zone and anoxic zone, and has a certain denitrification efficiency. However, the flow field in the traditional airlift internal circulation reactor tends to be fully mixed. For bioreactors, the efficiency in treating wastewater On the one hand, the push flow state is more efficient than the fully mixed flow state.

Utility model content

What the utility model aims to solve is the technical problem that the internal flow field of the existing air-lift internal circulation reactor tends to be fully mixed and the efficiency is low.

In order to solve the above technical problems, the utility model provides an air-lift external circulation vortex enhanced biological denitrification reactor, which is characterized in that it includes a water distribution section, a reaction section and a separation section from bottom to top, the water distribution section The section includes the lower short cylinder on the bottom plate, the lowest part of the outer side of the lower short cylinder is provided with an empty opening, the lower short cylinder is equipped with a water distributor and a microporous aeration disc, and the water distributor and the lower short cylinder The water inlet pipe on the outer side of the cylinder is connected, and the microporous aeration disc is connected to the air inlet pipe arranged on the outer side of the lower short cylinder; The upper and lower ends of the long cylinder and the upper and lower ports of the long cylinder respectively form a diversion area and a mixing area, and the left and right sides of the diversion area and the mixing area are respectively connected to form a circulation through the left circulation pipe and the right circulation pipe; the multi-stage Venturi tube The two ends are respectively fixed in the long cylinder through the upper and lower circular baffles; the separation section includes an upper short cylinder, which is equipped with a water outlet and air outlet system.

Preferably, the microporous aeration pan and the air inlet pipe are arranged on the same horizontal plane, the water inlet pipe and the water distributor are arranged on the same horizontal plane, and the microporous aeration pan and the air inlet pipe are arranged higher than the water inlet pipe and the water distributor, The water inlet pipe and water distributor are arranged higher than the emptying port.

Preferably, the lower end of the long cylinder is connected to the lower short cylinder through a lower flange, and the upper end is connected to the upper short cylinder through an upper flange.

Further, a lower screen is provided in the lower flange, and an upper screen is provided in the upper flange.

Preferably, the water outlet and air outlet system includes a conical air collection hood with a large mouth facing downwards, the conical air collection hood communicates with the atmosphere through an air guide tube, the upper end of the air guide tube is exposed from the upper side of the upper short cylinder, and the air guide tube passes through the annular overflow The flow weir is fixed in the upper short cylinder, and an outlet pipe is arranged above the annular overflow weir.

Further, the air guide cylinder is provided with a wire mesh demister, whose height in the air guide cylinder accounts for 1/5-1/4 of the height of the air guide cylinder, and can annihilate the foam brought out during the aeration process.

Preferably, the height ratio of the water distribution section, the reaction section, and the separation section is 1.0:(3.5-5.5):1.5; the diameters of the lower short cylinder, the upper short cylinder and the long cylinder are the same, and the height-to-diameter ratio is 5.5 ~7.0.

Preferably, the height of the mixing zone accounts for 1/8-1/7 of the height of the long cylinder.

Preferably, the multi-stage Venturi tube is composed of half Venturi tubes at both ends and two Venturi tubes of the same specification in the middle connected in sequence, between each half Venturi tube, each Venturi tube and the wall of the long cylinder Independent heat preservation areas are formed respectively. The lower part of one side of the heat preservation area is provided with a heat preservation water inlet, and the higher part of the other side is provided with a heat preservation water outlet.

Preferably, the height of the multi-stage Venturi tube accounts for 5/7 to 3/4 of the height of the long cylinder, and the ratio of the smallest diameter to the diameter of the long cylinder is: 1; the busbar of a single Venturi tube in the multi-stage Venturi tube The included angle with the horizontal plane is 50°～70°.

Preferably, the height of the diverging area accounts for 1/8-1/7 of the height of the long cylinder.

Preferably, the left circulation pipe and the right circulation pipe are in the shape of a symmetrical three-fold line with a folding angle of 100°-120°, and a ratio of its diameter to the diameter of the long cylinder is 0.45-0.65:1.

Mixing area, its two sides are respectively connected with the lower ends of the left and right circulation pipes, this area can dilute the feed concentration and initially realize the three-phase mixing of gas, liquid and solid; flow in this area. Circulation pipe, this structure is an anoxic zone, where biological denitrification occurs. The structure of the multi-stage Venturi tube is an aerobic zone, where biological nitrification occurs, and there is a vortex flow field in it, which can effectively enhance the mass transfer between phases. The heat preservation zone can realize the temperature increase of the reactor in winter. The upper and lower screens are respectively fixed by the upper and lower flanges, which can trap the biofilm carrier and prevent the biofilm carrier from washing out. The wire mesh demister can annihilate the foam brought out by the aeration process.

The present invention is a kind of biofilm reactor, there is a certain amount of filler inside, there are aerobic zone and anoxic zone in the reactor, can realize biological nitrification and denitrification denitrification, its main structure is a multi-stage Venturi tube, the structure is quite Due to the series connection of multiple fully mixed flow areas, the flow state of "fully mixed flow between stages and plug flow between stages" has been formed in terms of flow state. According to the theory of bioreactors, the removal efficiency of the push flow state is higher than that of the fully mixed flow, and the volume of the push flow state reactor to achieve the same treatment efficiency is less than that of the fully mixed flow. In addition, it has been verified by Fluent software simulation and operation test that there is a symmetrical vortex flow field in the multi-stage Venturi tube, which can effectively reduce the mass transfer resistance and enhance the mass transfer efficiency between gas-liquid-solid three-phase. Therefore, compared with the traditional air-lift internal circulation denitrification reactor, the present invention has better denitrification efficiency and volume efficiency.

Owing to adopting above-mentioned technical scheme, the present invention has following advantage and positive effect compared with prior art:

1) The setting of the mixing zone can make the inlet water intake and the return liquid of the circulation pipe violently mixed, fully mass transfer, and have the effect of diluting the inlet water, so that the reactor has a better resistance to impact loads, and because the structure can be set Appropriately simplifying the structure of the water distributor can save infrastructure costs;

2) A series of structural settings such as microporous aeration discs, multi-stage venturi tubes, and left and right circulation pipes make the multi-stage venturi tubes of the reactor in an aerobic state, and the left and right circulation pipes are in an anoxic state, making the reactor The reactor has the function of synchronous nitrification and denitrification biological denitrification;

3) The multi-stage Venturi tube is equivalent to the series connection of multiple shrinking and expanding structures, realizing the fully mixed flow between stages and the flow state of inter-stage plugging flow, which can form a vortex flow field locally in the tube, and there is a strong flow field in the vortex flow field. Shearing force can reduce the thickness of the liquid film during the mass transfer process, reduce the mass transfer resistance, and effectively enhance the mass transfer effect between the three phases;

4) The heat preservation zone and the inlet and outlet of circulating water are set up. When the temperature of the reactor system is low (<15°C), hot water or steam can be introduced to increase the temperature of the reactor to ensure the denitrification efficiency of nitrification and denitrification (nitrification and denitrification The normal temperature of the nitrification reaction generally needs to be above 15°C);

5) In the diversion area, the initial three-phase separation can be achieved by using the density difference and the upper screen, which paves the way for the circulation of the solid-liquid mixture and the two-phase separation of the conical gas collection hood;

6) The lower screen can prevent the filler from falling into the water distribution section, the upper screen can prevent the filler from being carried out of the reactor by the gas-liquid flow, and the upper screen can allow floc sludge or fallen biofilm to pass through, which can realize the reactor New and old replacement of internal flora;

7) The setting of the wire mesh demister on the outlet pipe can annihilate a large amount of foam brought out during the aeration process, ensure environmental sanitation, and ensure the stable operation of the system;

8) The main body is cylindrical, the diameters of the upper and lower ends are equal, the structure is compact, the mechanical strength is good, and the ratio of height to diameter of the reactor is large, the floor area is small, and the investment in infrastructure is effectively reduced.

9) It is suitable for the treatment of nitrogen-containing organic wastewater. After laboratory simulated waste water inflow test, its volume load can reach 8.5kg·COD/m ³ ·d at room temperature, and the volume load of total nitrogen is 0.56kg/m ³ ·d.

Description of drawings

Fig. 1 is a structural schematic diagram of an air-lift external circulation vortex enhanced biological denitrification reactor provided by the utility model;

Fig. 2 is a sectional view of plane A-A in Fig. 1 .

Detailed ways

In order to make the utility model more comprehensible, preferred embodiments are described in detail below with accompanying drawings.

Example

As shown in Figure 1-2, the structure diagram of the air-lift external circulation vortex enhanced biological denitrification reactor provided by the utility model includes water distribution section I, reaction section II and separation section III from bottom to top. The water distribution section 1 includes a lower short cylinder 3 arranged on the bottom plate 1, the lowest part of the outer side of the lower short cylinder 3 is provided with an emptying port 28, and the lower short cylinder 3 is provided with a water distributor 26, a microporous aeration The disc 25 and the water distributor 26 communicate with the water inlet pipe 2 arranged on the outside of the lower short cylinder 3 , and the microporous aeration disc 25 communicates with the air intake pipe 27 installed on the outer side of the lower short cylinder 3 . The microporous aeration pan 25 and the air inlet pipe 27 are set on the same level, the water inlet pipe 2 and the water distributor 26 are set on the same level, and the microporous aeration pan 25 and the air inlet pipe 27 are higher than the water inlet pipe 2 and the water distributor 26 arrangement, the water inlet pipe 2 and the water distributor 26 are arranged higher than the emptying port 28. The air guide cylinder 18 is provided with a wire mesh demister 19, whose height in the air guide cylinder 18 accounts for 1/5-1/4 of the height of the air guide cylinder 18, which can annihilate the foam brought out during the aeration process.

Described reaction section II comprises long cylinder 8, and long cylinder 8 is provided with multi-stage Venturi tube 10, and the upper and lower ends of multi-stage Venturi tube 10 and the upper and lower two ports of long cylinder 8 respectively form split flow area 13, The mixing zone 6, the diverging zone 13 and the mixing zone 6 occupy 1/8-1/7 of the height of the long cylinder 8, and the left and right sides of the diverging zone 13 and the mixing zone 6 are respectively connected through the left circulation pipe 11 and the right circulation pipe 23 Form a circulation; the left circulation pipe 11 and the right circulation pipe 23 are symmetrical three-fold line shape, the angle α is 100°～120°, and the ratio of its diameter d2 to the diameter D of the long cylinder 8 is 0.45～0.65:1. Two ends of the multi-stage Venturi tube 10 are respectively fixed in the long cylinder 8 through the upper circular baffle 12 and the lower circular baffle 24 . The lower end of the long cylinder 8 is connected with the lower short cylinder 3 through the lower flange 4 , and the upper end is connected with the upper short cylinder 15 through the upper flange 14 . The lower flange 4 is provided with a lower screen 5 , and the upper flange 14 is provided with an upper screen 21 . The height of the mixing zone 6 accounts for 1/8-1/7 of the height of the long cylinder 8; the height of the diversion zone 13 accounts for 1/8-1/7 of the height of the long cylinder 8. The multi-stage Venturi tube 10 is composed of half Venturi tubes at both ends and two Venturi tubes of the same specification in the middle, which are sequentially connected. Each half Venturi tube, each Venturi tube and the wall of the long cylinder 8 are respectively An independent thermal insulation zone 9 is formed, the lower part of one side of the thermal insulation zone 9 is provided with a thermal insulation water inlet 7, and the higher part of the other side is provided with a thermal insulation water outlet 22. The height of the multi-stage Venturi tube 10 accounts for 5/7-3/4 of the height of the long cylinder 8, and the ratio of its minimum diameter d1 to the diameter D of the long cylinder 8 is 0.4-0.6:1; a single venturi in the multi-stage Venturi tube 10 The angle β between the busbar of the inner tube and the horizontal plane is 50°-70°.

The separation section III includes an upper short cylinder 15, and the upper short cylinder 15 is provided with a water outlet and air outlet system. The water outlet and air outlet system includes a conical air collection hood 16 with a large mouth facing downward. The conical air collection hood 16 communicates with the atmosphere through an air guide cylinder 18. The upper end of the air guide cylinder 18 is exposed from the upper side of the upper short cylinder 15. The air guide cylinder 18 passes through the ring The overflow weir 17 is fixed in the upper short cylinder 15, and an outlet pipe 20 is arranged above the annular overflow weir 17. The air guide cylinder 18 is provided with a wire mesh demister 19, whose height in the air guide cylinder 18 accounts for 1/5-1/4 of the height of the air guide cylinder 18, which can annihilate the foam brought out during the aeration process.

The height ratio of the water distribution section I, the reaction section II, and the separation section III is 1.0:(3.5-5.5):1.5; the diameter D of the lower short cylinder 3, the upper short cylinder 15 and the long cylinder 8 are the same, and the height-to-diameter ratio 5.5-7.0.

The utility model can be made of PVC board or steel plate, and its working process is as follows:

A certain amount of filler is filled between the upper screen 21 and the lower screen 5, and microorganisms adhere to the filler in the form of a biofilm. Nitrogen-containing organic wastewater enters the water distributor 26 from the water inlet pipe 2 to distribute the water evenly, and then is brought to the mixing zone 6 of the reaction section II by the tiny air bubbles produced in the microporous aeration pan 25, and the wastewater and the left circulation in the mixing zone 6 The pipe 11 and the right circulation pipe 23 reflux the mixed liquid and mix it evenly, and then enter the multi-stage Venturi pipe 10 under the drive of the updraft. There is a symmetrical vortex flow field in the multi-stage Venturi tube 10, and the gas-liquid-solid three-phase fully contacts in the multi-stage Venturi tube 10 to obtain a better mass transfer effect. The multi-stage Venturi tube 10 is an aerobic zone, The nitrification step in the biological denitrification process occurs in this area, and NH ₃ -N is converted into NO ₃ ^- , then the mixed liquid enters the split flow area 13, part of the liquid enters the separation section III, and part of the liquid and all biofilm particles enter the left circulation pipe 11 , the right circulation pipe 23 backflow circulation, the left circulation pipe 11 and the right circulation pipe 23 are anoxic zones, where the denitrification step in the biological denitrification process occurs, and NO ₃ ⁻ is converted into N ₂ , which is collected by the conical gas collection hood 16 Most of the gas (including air and nitrogen produced by denitrification), the gas escapes into the air through the air guide cylinder 18, and the treated waste water is discharged from the annular overflow weir 17 and the outlet pipe 20. The liquid surface of the air guide tube 18 produces a large amount of foam, which is physically defoamed by the wire mesh demister 19. So far, the whole process of the reaction is completed. After laboratory simulated wastewater inflow test, its volume load can reach 8.5kg·COD/m ³ ·d at room temperature, and the volume load of total nitrogen is 0.56kg/m ³ ·d.

Claims (12)

1. an external loop airlift vortex enhanced biological nitrogen removal reactor, it is characterized in that, comprise water distribution section (I) from bottom to up, conversion zone (II) and segregation section (III), described water distribution section (I) comprises the lower short cylinder (3) of being located on base plate (1), the lowest part in lower short cylinder (3) outside is provided with and empties mouthful (28), in lower short cylinder (3), be provided with water distributor (26), microporous aeration disc (25), water distributor (26) is communicated with the water inlet pipe (2) of being located at lower short cylinder (3) outside, microporous aeration disc (25) is communicated with the inlet pipe (27) of being located at lower short cylinder (3) outside, described conversion zone (II) comprises long cylinder (8), in long cylinder (8), be provided with multistage Venturi tube (10), the two ends up and down of multistage Venturi tube (10) and long cylinder (8) between two ports, form respectively up and down shunting zone (13), mixing zone (6), the left and right sides of shunting zone (13), mixing zone (6) is communicated with and is formed circulation by left circulation tube (11), right circulation tube (23) respectively, the two ends of multistage Venturi tube (10) are fixed in long cylinder (8) by upper annulus baffle plate (12), lower annulus baffle plate (24) respectively, described segregation section (III) comprises short cylinder (15), is provided with the water outlet system of giving vent to anger in upper short cylinder (15).

2. external loop airlift vortex enhanced biological nitrogen removal reactor as claimed in claim 1, it is characterized in that, described microporous aeration disc (25) is located in same level with inlet pipe (27), water inlet pipe (2) is located in same level with water distributor (26), and microporous aeration disc (25), inlet pipe (27) are higher than water inlet pipe (2), water distributor (26) layout, and water inlet pipe (2), water distributor (26) are arranged higher than emptying mouthful (28).

3. external loop airlift vortex enhanced biological nitrogen removal reactor as claimed in claim 1, it is characterized in that, the lower end of described long cylinder (8) is connected with lower short cylinder (3) by lower flange (4), and upper end is connected with upper short cylinder (15) by upper flange (14).

4. external loop airlift vortex enhanced biological nitrogen removal reactor as claimed in claim 3, is characterized in that, is provided with lower screen cloth (5) in described lower flange (4), is provided with upper screen cloth (21) in upper flange (14).

5. external loop airlift vortex enhanced biological nitrogen removal reactor as claimed in claim 1, it is characterized in that, the described water outlet system of giving vent to anger comprises large mouth taper gas skirt (16) down, taper gas skirt (16) is communicated with atmosphere by gas cylinder (18), expose from upper short cylinder (15) upside the upper end of gas cylinder (18), gas cylinder (18) is fixed in upper short cylinder (15) by annular overflow weir (17), and annular overflow weir (17) top is provided with rising pipe (20).

6. external loop airlift vortex enhanced biological nitrogen removal reactor as claimed in claim 5, it is characterized in that, in described gas cylinder (18), be provided with wire mesh demister (19), its height in gas cylinder (18) accounts for 1/5～1/4 of gas cylinder (18) height, can bury in oblivion the foam that aeration process is taken out of.

7. external loop airlift vortex enhanced biological nitrogen removal reactor as claimed in claim 1, is characterized in that, the aspect ratio of described water distribution section (I), conversion zone (II), segregation section (III) is 1.0: (3.5～5.5): 1.5; Lower short cylinder (3), upper short cylinder (15) are identical with the diameter (D) of long cylinder (8), and aspect ratio is 5.5～7.0.

8. external loop airlift vortex enhanced biological nitrogen removal reactor as claimed in claim 1, is characterized in that, described mixing zone (6) highly account for 1/8～1/7 of long cylinder (8) height.

9. external loop airlift vortex enhanced biological nitrogen removal reactor as claimed in claim 1, it is characterized in that, described multistage Venturi tube (10) is connected to form successively by half Venturi tube and two middle identical Venturi tubes of specification at two ends, between the barrel of half and half Venturi tube, each Venturi tube and long cylinder (8), form respectively independently heat preservation zone (9), the lower of heat preservation zone (9) one sides is provided with insulation water inlet (7), and the higher position of opposite side is provided with insulation water out (22).

10. the external loop airlift vortex enhanced biological nitrogen removal reactor as described in claim 1 or 9, it is characterized in that, the height of described multistage Venturi tube (10) accounts for 5/7～3/4 of long cylinder (8) height, and its minimum diameter (d1) is (0.4～0.6) with the ratio of long cylinder (8) diameter (D): 1; In multistage Venturi tube (10), the bus of single Venturi tube and the angle between horizontal plane (β) are 50 °～70 °.

11. external loop airlift vortex enhanced biological nitrogen removal reactors as claimed in claim 1, is characterized in that, described shunting zone (13) highly account for 1/8～1/7 of long cylinder (8) height.

12. external loop airlift vortex enhanced biological nitrogen removal reactors as claimed in claim 1, it is characterized in that, described left circulation tube (11), right circulation tube (23) are symmetrical tri linear shape, knuckle (α) is 100 °～120 °, and its diameter (d2) is 0.45～0.65: 1 with the ratio of long cylinder (8) diameter (D).