PTA chemical wastewater biochemical excess sludge air flotation concentration device

Abstract

The utility model relates to the technical field of sludge treatment, in particular to an air flotation concentration device for PTA chemical wastewater biochemical excess sludge, and solves the problem that an original horizontal-flow sludge concentration tank is poor in concentration effect on the PTA chemical wastewater biochemical excess sludge. The coagulation reaction tank comprises a first-stage coagulation reaction tank, a second-stage coagulation reaction tank and a water distribution area which are communicated with one another; stirrers are arranged in the two coagulation reaction tanks; the cavitation aeration tanks are connected with the coagulation reaction tank through holes, and each cavitation aeration tank is provided with a cavitation aerator; the air flotation separation tank is communicated with each cavitation aeration tank; the top of the tank is provided with a plurality of slag scrapers, and the bottom is provided with a plurality of sludge discharge buckets; a scum collecting tank is arranged at one end far away from the cavitation aeration tank, and a scum scraping inclined bank is connected to the scum collecting tank; the scum collecting tank is provided with a scum discharge port; and a water outlet is also formed in the side wall of the tank. The treatment process is simple, the adaptability is high, the treatment efficiency is high, the operation is stable, the energy consumption is low, the automation degree is high and the operation is continuous.

Description

Technical Field

[0001] This utility model relates to the field of sludge treatment technology, and in particular to a PTA chemical wastewater biochemical wastewater residual sludge air flotation thickening device. Background Technology

[0002] Purified terephthalic acid (PTA) is an important organic chemical raw material, and the wastewater discharged during its production process has the following characteristics:

[0003] (1) High COD and BOD, COD 5000-15000 mg / L, BOD 52000-6000 mg / L.

[0004] (2) High organic pollutants, including aromatic compounds such as terephthalic acid (TA), p-methylbenzoic acid (p-TA), and benzoic acid (BA).

[0005] (3) Strong acidity, the wastewater is acidic, and the pH value is usually between 3 and 5.

[0006] (4) High salt content, containing a large amount of inorganic salts, such as sodium acetate and sodium sulfate, with high conductivity.

[0007] (5) High color intensity: the wastewater is usually dark yellow or brown, with a high color intensity.

[0008] (6) High temperature, the temperature is relatively high when it is discharged, usually between 40-60℃.

[0009] (7) Toxicity: It contains aromatic compounds that are toxic to microorganisms, which affect the effectiveness of biological treatment.

[0010] (8) Difficult to degrade: Some organic matter is difficult to biodegrade, which increases the difficulty of treatment.

[0011] (9) May contain trace amounts of heavy metals, such as cobalt and manganese, which may come from the catalyst.

[0012] For the treatment of residual sludge from PTA chemical wastewater, air flotation thickening is generally used. Specifically, microbubbles (air or nitrogen) are injected into the sludge, causing sludge particles to adhere to the bubbles and float to the surface, forming a scum layer which is then scraped off. This method is suitable for lightweight sludge with a density close to water that is difficult to settle.

[0013] The prior art provides a vortex-induced air flotation device for sludge thickening (see patent CN111204953A), but the vortex-induced air flotation device disclosed therein is mainly for thickening residual sludge from municipal sewage biochemical treatment, and is a new project with a steel structure for the tank body. Utility Model Content

[0014] The purpose of this invention is to provide a PTA chemical wastewater biochemical residue sludge air flotation thickening device, which solves the problems of large footprint and low thickening efficiency of the original horizontal flow sludge thickening tank.

[0015] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0016] This utility model provides a PTA chemical wastewater biochemical wastewater residual sludge air flotation thickening device, comprising:

[0017] The coagulation reaction tank includes a primary coagulation reaction tank, a secondary coagulation reaction tank, and a water distribution area that are connected to each other; both the primary coagulation reaction tank and the secondary coagulation reaction tank are equipped with a mixer.

[0018] A plurality of vortex aeration tanks are provided, and each vortex aeration tank is connected to the coagulation reaction tank through an opening; and each vortex aeration tank is provided with a vortex aerator.

[0019] An air flotation separator is provided, which is connected to each of the aforementioned vortex aeration tanks; several sludge scrapers are provided at the top of the air flotation separator, and several sludge discharge hoppers are provided at the bottom of the air flotation separator; a scum collection trough is provided at the end of the air flotation separator away from the vortex aeration tank, and a scum scraper inclined bank is connected to the scum collection trough; a scum discharge port is provided in the scum collection trough; and a water outlet is also provided on the side wall of the air flotation separator.

[0020] Furthermore, the primary coagulation reaction tank is provided with a feed inlet and a demulsifier dosing inlet at its top; the water distribution zone is provided with a flocculant dosing inlet at its top.

[0021] Furthermore, the stirring speed of the agitator in the primary coagulation reaction tank is greater than that of the agitator in the secondary coagulation reaction tank.

[0022] Furthermore, the slag scraper is equipped with several scrapers with equal spacing.

[0023] Furthermore, the slag scraper slope works in conjunction with the slag scraper located closest to the outlet end of the air flotation separator. When the scraper blade on the slag scraper moves above the slag scraper slope, the scraper blade contacts the lowest point of the inclined surface of the slag scraper slope.

[0024] Furthermore, the bottom of each of the sludge discharge hoppers is connected to a discharge branch pipe, and a discharge valve is provided on the discharge branch pipe; each of the discharge branch pipes converges into the main discharge pipe.

[0025] Furthermore, a screw propeller is provided in the scum collection tank to prevent scum from accumulating in the scum collection tank and to drive the scum to move.

[0026] Furthermore, an adjustable overflow weir plate is provided at the outlet to regulate and control the water level.

[0027] Due to the application of the above technical solution, this utility model has the following advantages:

[0028] This invention relates to a PTA chemical wastewater biochemical residue sludge air flotation thickening device, which modifies an existing horizontal flow sludge thickening tank into a vortex-type air flotation sludge thickening tank. A concrete partition wall is used at the front end of the tank to create a primary and secondary coagulation reaction tank. Through two-stage coagulation, the aim is to coagulate the sludge into more robust flocs, reduce sludge redissolution, and improve the coagulation treatment effect.

[0029] Secondly, by setting up several vortex-shaped aeration tanks, the vortex-shaped aeration tanks are directly connected to the coagulation reaction tank through openings, which ensures uniform aeration treatment and improves the efficiency of aeration operations.

[0030] After treatment by the vortex-type air flotation thickener, the water content of the air flotation sludge can reach 93%~96%, and the volume of the sludge after thickening is reduced to about 20% of that before thickening. This device is simple to operate, highly adaptable, has high processing efficiency, relatively low energy consumption, and is economical and convenient to maintain. Attached Figure Description

[0031] The following sections will describe some specific embodiments of the present invention in a detailed manner by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0032] Figure 1 This is a schematic diagram of the structure of a PTA chemical wastewater biochemical wastewater residual sludge air flotation thickening device provided by this utility model;

[0033] Figure 2 This is a schematic diagram of the structure of the vortex aerator provided by this utility model;

[0034] Figure 3 This is a schematic diagram of the adjustable overflow weir plate provided by this utility model;

[0035] The reference numerals in the attached figures are explained as follows:

[0036] 1. Coagulation reaction tank; 10a. Primary coagulation reaction tank; 10b. Secondary coagulation reaction tank; 100. Mixer; 101. Feed inlet; 102. Demulsifier dosing port; 11. Water distribution area; 110. Flocculant dosing port;

[0037] 2. Vortex aeration tank; 20. Vortex aerator; 201. Hollow impeller; 202. Hollow pipe;

[0038] 3. Air flotation separator; 30. Scum scraper; 300. Scraper; 31. Sludge hopper; 310. Drainage branch pipe; 311. Drainage valve; 312. Drainage main pipe; 32. Scum collection tank; 320. Screw propeller; 33. Scum scraper inclined bank; 34. Scum discharge port; 35. Water outlet; 350. Adjustable overflow weir plate. Detailed Implementation

[0039] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0040] See Figure 1 The PTA chemical wastewater biochemical wastewater residual sludge air flotation thickening device of this utility model includes a coagulation reaction tank 1, a vortex aeration tank 2, and an air flotation separation tank 3. In this embodiment, the PTA chemical wastewater biochemical wastewater residual sludge air flotation thickening device is modified from an existing horizontal flow sludge thickening tank, using a concrete structure. Furthermore, while the original horizontal flow sludge thickening tank was partially buried underground, in this embodiment, the bottom of the coagulation reaction tank 1 is raised to the ground level, reducing the volume of the coagulation reaction tank 1, shortening the reaction residence time, and improving treatment efficiency.

[0041] In this embodiment, the coagulation reactor 1 includes a primary coagulation reactor 10a, a secondary coagulation reactor 10b, and a water distribution zone 11 that are interconnected. Segmented optimization of coagulation conditions allows for more effective use of reagents, avoiding over-dosing and thus reducing operating costs. Furthermore, the two-stage reaction results in a denser, stronger floc structure, making it easier for the flocs to float during air flotation, improving solid-liquid separation efficiency. Insufficient floc strength can lead to breakage and re-dissolution during air flotation. The two-stage coagulation reactor forms more robust flocs, reducing sludge re-dissolution and improving treatment efficiency.

[0042] In this embodiment, the primary coagulation reactor 10a is mainly used for preliminary coagulation, allowing suspended solids, colloidal particles, etc., in the wastewater to fully contact with the coagulant and form fine flocs. This stage requires rapid mixing of the coagulant and preliminary flocculation. The secondary coagulation reactor 10b mainly further coagulates and grows the fine flocs formed in the primary reactor, making the flocs more stable and dense, facilitating subsequent air flotation separation. Since the flocs have already been initially formed at this stage, the reaction rate is relatively slow to prevent the formed flocs from breaking.

[0043] Both the primary coagulation reactor 10a and the secondary coagulation reactor 10b are equipped with a mixer 100, which aims to increase the mixing effect of the added reagents and sludge, and to fully carry out coagulation treatment.

[0044] The primary coagulation reactor 10a has an inlet 101 and a demulsifier dosing port 102 at its top. The inlet 101 allows the sludge to be treated to enter, while the dosing port 102 is used to add demulsifier to the primary coagulation reactor 10a. Because the sludge contains a large number of colloidal particles, these particles carry the same charge (usually negative), repelling each other and causing them to remain suspended in water and difficult to settle. The demulsifier can neutralize these charges, eliminate electrostatic repulsion, destabilize the colloidal particles, promote flocculation and sedimentation, thereby improving sludge dewatering efficiency, reducing sludge volume, and lowering subsequent treatment costs. Compared to existing technologies where ordinary coagulants are added to the primary coagulation reactor 10a for concentrating residual sludge from municipal wastewater biochemical treatment, demulsifiers are added to the primary coagulation reactor 10a for concentrating residual sludge from PTA chemical wastewater biochemical treatment, depending on the wastewater's characteristics.

[0045] The top of the water distribution zone 11 is equipped with a flocculant dosing port 110. The flocculant acts like "glue," binding together the fine particles in the sludge to form larger flocs, making it easier to settle and dewater, thus improving sludge treatment efficiency.

[0046] In this embodiment, several vortex aeration tanks 2 are provided, and each vortex aeration tank 2 is connected to the aforementioned coagulation reaction tank 1 through an opening. Compared with the prior art, which uses excessively long pipes to connect the coagulation reaction tank 1 and the vortex aeration tank 2, the direct opening connection reduces the residence time of sludge in the pipes, avoiding blockages that could affect subsequent treatment. Furthermore, since several vortex aeration tanks 2 are provided, and each vortex aeration tank 2 is equipped with a corresponding vortex aerator 20, the sludge in the coagulation reaction tank 1 can be evenly dispersed into each vortex aeration tank 2 for aeration treatment, ensuring uniformity of aeration treatment and improving aeration efficiency.

[0047] In this embodiment, see Figure 2 The vortex aerator 20 is vertically installed in the vortex aeration tank 2. The bottom of the vortex aerator 20 is equipped with a hollow impeller 201. The high-speed rotating hollow impeller 201 forms a micro-negative pressure vacuum zone in the vortex aeration tank 2. At this time, the air on the water surface is drawn to the water through the hollow pipe 202 on the vortex aerator 20. Under the rapid rotation of the hollow impeller 201 at the bottom, the air is crushed into microbubbles by the three shear forces generated. The microbubbles organically combine with the solid pollutants in the sewage and rise to the liquid surface.

[0048] The coagulation reaction tank 1 and the vortex aeration tank 2 are directly connected by an opening. The opening is located above the hollow impeller 201 of the vortex aerator 20 in the vortex aeration tank 2. When the sludge after coagulation treatment enters the vortex aeration tank 2, it will be quickly dispersed by the hollow impeller 201, rapidly aerated, and covered with air bubbles, effectively improving the treatment efficiency.

[0049] The dissolved air flotation (DAF) separator 3 is connected to each of the aforementioned vortex aeration tanks 2. Several scrapers 30 are installed at the top of the DAF separator 3 to scrape away the concentrated sludge suspended above the liquid surface. The scrapers 30 are driven by a motor and have several equally spaced scraper blades 300. When the scrapers 30 are in operation, the scraper blades 300 also rotate in a cycle to scrape away the concentrated sludge suspended on the liquid surface.

[0050] A scum collection trough 32 is provided at the end of the air flotation separator 3 furthest from the vortex aeration tank 2, and a scum scraper slope 33 is simultaneously connected to the scum collection trough 32. The scum scraper slope 33 has the functions of thickening, enriching, and skimming scum. Through the scraping operation of the scraper 30, with the assistance of the scum scraper slope 33, the thickened sludge is collected into the scum collection trough 32. Specifically, the scum scraper slope 33 works in conjunction with the scraper 30 at the outlet end closest to the air flotation separator 3. When the scraper blade 300 on the scraper 30 moves above the scum scraper slope 33, the scraper blade 300 contacts the lowest point of the inclined surface of the scum scraper slope 33, guiding the sludge into the scum collection trough 32.

[0051] The scum collection tank 32 is equipped with a scum discharge port 34, and the concentrated sludge in the scum collection tank 32 enters the subsequent dewatering equipment.

[0052] The scum collection tank 32 is also equipped with a screw propeller 320. The stirring effect generated by the screw propeller 320 can prevent the scum from accumulating into lumps or hardening in the collection tank. At the same time, it can also push the scum to the above-mentioned scum discharge port 34, which significantly improves the scum collection efficiency, prevents blockage, improves water flow distribution, and reduces manual cleaning costs.

[0053] To address the issue of heavy solid pollutants in the sludge that cannot float, this embodiment includes several sludge discharge hoppers 31 at the bottom of the air flotation separator 3. Each sludge discharge hopper 31 is connected to a drain branch pipe 310, which is equipped with a drain valve 311. The sludge from the sludge discharge hoppers 31 is guided through the drain branch pipe 310 into the main drain pipe 312, and then to downstream equipment for further processing. The drain valve 311 controls the flow of heavy sludge.

[0054] In addition, an outlet 35 is provided on the side wall of the air flotation separator 3. The outlet 35 is used to discharge the clarified liquid after solid-liquid separation. An adjustable overflow weir 350 is also provided here to adjust and control the water level according to the concentration and amount of sludge being treated. The adjustable overflow weir 350 can be adjusted manually or automatically. In this embodiment, see [reference needed]. Figure 3 The height of the adjustable overflow weir plate 350 is adjusted by tightening bolts, thereby controlling the water level.

[0055] Based on the residual sludge from PTA chemical wastewater of a petrochemical company, with a moisture content of 99.5%~99.7% and a pH value of 7~8.5, the vortex-induced air flotation thickening device in this embodiment is used for sludge treatment. The moisture content of the air-flotated sludge is controlled at 94%~96%, and the volume of the sludge after thickening is reduced to approximately 20% of that before thickening. The PTA chemical wastewater biochemical residual sludge air flotation thickening device disclosed in this embodiment has a simple treatment process, strong adaptability, high treatment efficiency, stable operation, low energy consumption, high degree of automation, and continuous operation.

[0056] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the protection scope of this utility model.

Claims

1. A PTA chemical wastewater biochemical residual sludge air flotation concentration device, characterized in that, include: The coagulation reaction tank (1) includes a primary coagulation reaction tank, a secondary coagulation reaction tank and a water distribution area that are connected to each other; both the primary coagulation reaction tank and the secondary coagulation reaction tank are equipped with a mixer (100). A vortex aeration tank (2) is provided in several ways, and each vortex aeration tank (2) is connected to the coagulation reaction tank (1) through an opening; and each vortex aeration tank (2) is provided with a vortex aerator (20). An air flotation separator (3) is connected to each of the vortex aeration tanks (2); a number of sludge scrapers (30) are provided at the top of the air flotation separator (3), and a number of sludge discharge hoppers (31) are provided at the bottom of the air flotation separator (3); a scum collection trough (32) is provided at the end of the air flotation separator (3) away from the vortex aeration tank (2), and a sludge scraper inclined bank (33) is connected to the scum collection trough (32); a scum discharge port (34) is provided in the scum collection trough (32); and a water outlet (35) is also provided on the side wall of the air flotation separator (3).

2. The PTA chemical wastewater biochemical residual sludge gas floating concentration device according to claim 1, characterized in that, The primary coagulation reactor is provided with a feed inlet (101) and a demulsifier dosing inlet (102) at the top; the water distribution zone is provided with a flocculant dosing inlet (110) at the top.

3. The PTA chemical wastewater biochemical residual sludge gas floating concentration device according to claim 1, characterized in that, The stirring speed of the agitator (100) in the primary coagulation reaction tank is greater than that of the agitator (100) in the secondary coagulation reaction tank.

4. The PTA chemical wastewater biochemical residual sludge gas floating concentration device according to claim 1, characterized in that, The slag scraper (30) is provided with several scrapers (300) with equal spacing.

5. The PTA chemical wastewater biochemical residual sludge gas floating concentration device according to claim 4, characterized in that, The slag scraper slope (33) works in conjunction with the slag scraper (30) located at the outlet end closest to the air flotation separator (3). When the scraper (300) on the scraper (30) moves above the slag scraper slope (33), the scraper (300) contacts the lowest point of the inclined surface of the slag scraper slope (33).

6. The PTA chemical wastewater biochemical residual sludge gas floating concentration device according to claim 1, characterized in that, The bottom of each of the sludge discharge hoppers (31) is connected to a discharge branch pipe (310), and a discharge valve (311) is provided on the discharge branch pipe (310); each of the discharge branch pipes (310) converges into the discharge main pipe (312).

7. The PTA chemical wastewater biochemical residual sludge gas floating concentration device according to claim 1, characterized in that, A spiral propeller (320) is provided in the scum collection tank (32) to prevent scum from accumulating in the scum collection tank (32) and to push the scum to move.

8. The PTA chemical wastewater biochemical residual sludge gas floating concentration device according to claim 1, characterized in that, An adjustable overflow weir plate (350) is provided at the outlet (35) to regulate and control the water level.

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