CN110950511B

CN110950511B - System and method for treating excess biochemical sludge

Info

Publication number: CN110950511B
Application number: CN201811125928.7A
Authority: CN
Inventors: 袁清; 秦娅; 毛俊义; 朱振兴; 赵锐; 桑军强; 黄涛; 庞博
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2018-09-26
Filing date: 2018-09-26
Publication date: 2022-07-15
Anticipated expiration: 2038-09-26
Also published as: CN110950511A

Abstract

The present disclosure relates to a system and method for treating excess biochemical sludge. The system comprises a raw material inlet, a mixed reaction device, a solid-liquid separation device, a sewage outlet and a concentrated sludge outlet; the mixing reaction equipment comprises a shell with a feeding hole and a discharging hole, wherein a material circulating pipeline is arranged outside the shell and is respectively communicated with the inside of the shell through a circulating material inlet and a circulating material outlet; the raw material inlet is communicated with the feed inlet of the mixing reaction equipment, the discharge outlet of the mixing reaction equipment is communicated with the inlet of the solid-liquid separation equipment, and the liquid outlet and the solid outlet of the solid-liquid separation equipment are respectively communicated with the sewage outlet and the concentrated sludge outlet. The treatment system and the treatment method realize high-efficiency mixing of a sludge liquid-solid heterogeneous system through external circulation mixing and internal reinforced mixing, and reinforce and promote a sludge reduction reaction process.

Description

System and method for treating excess biochemical sludge

Technical Field

The disclosure relates to the field of solid waste reduction and recycling application, and in particular relates to a system and a method for treating excess biochemical sludge.

Background

In recent years, the environmental protection industry in China is rapidly developed, the sewage treatment capacity and the treatment rate are rapidly improved, 3976 seats of sewage treatment plants are built up cumulatively in China at the end of 2016 (9) months, and the daily sewage treatment capacity reaches 1.7 billion cubic meters, which undoubtedly plays an important role in protecting the water environment. But at the same time, the sewage treatment process generates a large amount of residual activated sludge, 130 million cubic meters of residual activated sludge containing 98 w% of water is generated every day, and 4.75 billion cubic meters of residual activated sludge is generated every year, and the amount is huge based on the residual activated sludge generated by the current sewage treatment.

Because the residual activated sludge has serious pollution to the environment, complex components and difficult treatment, the residual activated sludge has been a problem caused by sewage treatment, and thus the residual activated sludge has become a focus of attention of people. In order to solve the problem of environmental pollution caused by the residual activated sludge, people develop a large amount of research and development work on the reduction of the residual activated sludge, and develop a series of reduction technologies, such as a residual activated sludge drying and burying technology, a composting technology, an incineration technology and the like. The technologies have certain effect on the reduction of the residual activated sludge, but have obvious defects, for example, the drying landfill technology not only occupies a large amount of land, but also has pollution risk to underground water, the composting technology can cause heavy metal pollution and biological pollution to soil in the using process, the incineration technology has high requirements on equipment and high treatment cost, and harmful gas polluting atmosphere can be generated.

Patent CN 105859088 discloses a supercritical sludge treatment system and method, which makes the sludge slurry undergo a combustion reaction in a reactor by adding an oxidant and carbonaceous organic matter powder, so the reaction conditions are very harsh.

Disclosure of Invention

The system has a simple structure, is convenient to operate, and has high treatment efficiency and good treatment effect on the excess biochemical sludge.

In order to achieve the above object, a first aspect of the present disclosure provides a system for treating surplus biochemical sludge, the system comprising a raw material inlet, a mixing reaction device, a solid-liquid separation device, a sewage outlet, and a concentrated sludge outlet; the mixing reaction equipment comprises a shell with a feeding hole and a discharging hole, wherein a material circulating pipeline is arranged outside the shell and is respectively communicated with the inside of the shell through a circulating material inlet and a circulating material outlet; the raw material inlet is communicated with the feed inlet of the mixed reaction equipment, the discharge outlet of the mixed reaction equipment is communicated with the inlet of the solid-liquid separation equipment, and the liquid outlet and the solid outlet of the solid-liquid separation equipment are respectively communicated with the sewage outlet and the concentrated sludge outlet.

Optionally, the housing is a vertical cylinder, the number of the second material mixing units is one or more, and the second material mixing units are axially arranged in the housing at intervals.

Optionally, the second material mixing unit comprises a first partition and a mixing and dispensing assembly; the first clapboard is arranged in the shell along the radial direction, and the edge of the first clapboard is hermetically connected with the inner wall of the shell so as to divide the interior of the shell into a first mixing reaction chamber and a second mixing reaction chamber from bottom to top; the mixing and distributing assembly is fixedly connected with the first partition plate, an inlet of the mixing and distributing assembly penetrates through the first partition plate, and an outlet of the mixing and distributing assembly is communicated with the second mixing and reacting chamber, so that the first mixing and reacting chamber and the second mixing and reacting chamber are communicated only through the mixing and distributing assembly; the feed inlet and the circulating material inlet are respectively communicated with the first mixing reaction chamber, and the discharge outlet and the circulating material outlet are respectively communicated with the second mixing reaction chamber.

Optionally, the mixing and distributing assembly is disposed on the first partition plate along the axial direction of the housing, the mixing and distributing assembly includes a second static mixer and a distributor which are sequentially communicated, an inlet of the second static mixer penetrates through the first partition plate, and an outlet of the distributor is communicated with the second mixing and reacting chamber.

Optionally, the second static mixer is a tubular static mixer, the distributor is formed as a distribution pipe that is coaxial with the second static mixer in an equal diameter, a bottom end of the distribution pipe is open to communicate with an outlet of the second static mixer, a top end of the distribution pipe is closed, and a pipe wall of the distribution pipe is formed with a plurality of distribution holes that are evenly distributed around a circumferential direction to form an outlet of the distributor.

Optionally, the second material mixing unit comprises a first partition plate and a plurality of mixing and distributing assemblies, and the plurality of mixing and distributing assemblies are uniformly distributed on the first partition plate.

Optionally, the second material mixing unit further comprises a collecting device disposed in the first mixing reaction chamber; the collecting device comprises a second partition plate which is arranged in parallel with the first partition plate at an interval, the edge of the second partition plate is connected with the inner wall of the shell in a sealing mode so as to form a buffering distribution chamber between the first partition plate and the second partition plate, and a through hole is formed in the second partition plate so as to communicate the buffering distribution chamber with the first mixing reaction chamber.

Optionally, the collecting device further includes a guide shell, the guide shell is fixed to the outer side of the buffer distribution chamber and covers the through hole, and a side wall of the guide shell has an opening to form an inlet of the collecting device.

Optionally, the through hole is located in the center of the second partition plate, and the second partition plate and the guide shell are coaxially arranged.

Optionally, the openings are multiple and arranged at equal intervals along the circumference of the cylinder of the guide shell.

Optionally, a plurality of baffle sleeves are arranged in the guide cylinder at intervals coaxially so as to form a baffle channel in the guide cylinder; or mixed filler is arranged in the guide shell.

Optionally, the mixing reaction equipment further comprises a fluid distribution device disposed in the first mixing reaction chamber, an inlet of the fluid distribution device is communicated with the circulating material inlet, and an outlet of the fluid distribution device is communicated with the first mixing reaction chamber and faces the feed inlet.

Optionally, the fluid distribution means is selected from at least one of a pipe distributor, a trough distributor, a disc distributor, an impingement distributor, a nozzle distributor, a pagoda distributor, and a shower distributor.

Optionally, the first material mixing unit comprises a single-tube static mixer and/or a shell and tube static mixer.

Optionally, the material circulation pipeline is connected with a circulation pump, and the circulation pump is arranged between the circulation material outlet and the first material mixing unit.

Optionally, the solid-liquid separation equipment comprises a cyclone separator and a settling tank, an inlet of the cyclone separator is communicated with a discharge hole of the mixed reaction equipment, a liquid outlet of the cyclone separator is communicated with the sewage outlet, a solid outlet of the cyclone separator is communicated with an inlet of the settling tank, and a liquid outlet and a solid outlet of the settling tank are respectively communicated with the sewage outlet and the concentrated sludge outlet.

Optionally, the solid-liquid separation equipment includes the settling cask, the jar body upper portion of settling cask is equipped with cyclone, cyclone's entry pass the settling cask and with mixed reaction equipment's discharge gate intercommunication, cyclone's solid outlet with the internal portion of the jar of settling cask intercommunication, cyclone with the liquid outlet of settling cask respectively with the sewage outlet intercommunication, the solid outlet of settling cask with concentrated sludge outlet intercommunication.

Optionally, the system further comprises an auxiliary agent inlet, and the auxiliary agent inlet is communicated with the feed inlet of the mixing reaction equipment.

Optionally, the system includes a feed pump disposed between the feedstock inlet and the mixing reaction device.

Optionally, the system includes a heat exchanger disposed between the feedstock inlet and the mixing reaction device.

A second aspect of the present disclosure provides a method for treating excess biochemical sludge using the system according to the first aspect of the present disclosure.

A third aspect of the present disclosure provides a method for treating excess biochemical sludge, the method comprising the steps of:

s1, under the condition of the reduction reaction, the residual biochemical sludge and the auxiliary agent are subjected to the reduction reaction in the mixed reaction equipment to obtain a reduction reaction product;

s2, mixing at least part of the mixed materials in the mixed reaction equipment as circulating materials outside the mixed reaction equipment, and returning the mixed materials to the mixed reaction equipment;

s3, carrying out solid-liquid separation on the products of the reduction reaction to respectively obtain sewage and concentrated sludge.

Optionally, the subtractive reaction conditions comprise: the reaction temperature is 80-300 ℃; the reaction pressure is 0.05MPa to 10.0 MPa; the addition amount of the auxiliary agent is such that the pH value of the mixed material in the mixed reaction equipment is 8-14; the retention time of the residual biochemical sludge in the mixed reaction equipment is 0.1-6.0 h.

Optionally, the solid content of the excess biochemical sludge is 1 w% to 10 w%.

Optionally, the auxiliary agent is an alkaline auxiliary agent selected from at least one of sodium hydroxide, potassium hydroxide, sodium oxide, sodium peroxide, potassium oxide, potassium peroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

Optionally, the mass flow ratio of the circulating material to the residual biochemical sludge feeding amount is 0.5-5.0.

Optionally, the solid-liquid separation comprises a cyclonic separation and gravity settling in sequence.

The system and the method for treating the excess biochemical sludge have the beneficial effects that:

(1) the system and the method for treating the excess biochemical sludge realize the high-efficiency mixing of a sludge liquid-solid heterogeneous system through the external circulation mixing and the internal reinforced mixing, and further reinforce the sludge reduction reaction process; and because the adopted static mixing process does not have special mechanical stirring and mixing equipment, the problem of leakage of the dynamic seal is effectively avoided.

(2) The system for treating the excess biochemical sludge provided by the invention has the advantages of simple structure, convenient operation, mild conditions, cheap and easily obtained reagents and the like, and is convenient to popularize and apply.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure, but do not constitute a limitation of the disclosure. In the drawings:

FIG. 1 is a process flow diagram of one embodiment of the disclosed systems and methods for treating excess biochemical sludge.

FIG. 2 is a schematic view of a mixing reaction apparatus according to an embodiment of the system for treating excess biochemical sludge according to the present disclosure.

FIG. 3 is a schematic view showing the construction of the second material mixing unit of the mixing reaction apparatus of one embodiment of the system for treating excess biochemical sludge according to the present disclosure.

FIG. 4 is a schematic view of a mixing distribution module of a mixing reaction apparatus according to an embodiment of the system for treating excess biochemical sludge according to the present disclosure.

FIG. 5 is a schematic view of the structure of a mixing distribution module of a mixing reaction apparatus of another embodiment of the system for treating excess biochemical sludge according to the present disclosure.

Description of the reference numerals

1 raw material inlet 2 auxiliary agent inlet

3 feed pump 4 heat exchanger

5 mixing reaction equipment 51 feed inlet

52 housing 53 fluid distribution apparatus

54 draft tube 55 mix dispensing assembly

551 second static mixer 552 distributor

56 circulating pump 57 first material mixing unit

58 discharge port 59 material circulation pipeline

591 circulating material inlet 592 circulating material outlet

510 first partition 511 second partition

6 cyclone separator 7 settling cask

8 sewage outlet and 9 concentrated sludge outlet

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

In the present disclosure, unless otherwise stated, the use of directional words such as "up" and "down" generally refers to the up and down of the device in normal use, and specifically refers to the orientation of the drawing in fig. 1. The "inner and outer" are with respect to the outline of the device itself.

As shown in fig. 1, the first aspect of the present disclosure provides a system for treating surplus biochemical sludge, which includes a raw material inlet 1, a mixing reaction apparatus 5, a solid-liquid separation apparatus, a sewage outlet 8, and a concentrated sludge outlet 9; the mixing reaction device 5 comprises a shell 52 with a feeding hole 51 and a discharging hole 58, a material circulating pipeline 59 is arranged outside the shell 52, the material circulating pipeline 59 is communicated with the inside of the shell 52 through a circulating material inlet 591 and a circulating material outlet 592 respectively, a first material mixing unit is connected to the material circulating pipeline 59, a second material mixing unit is arranged in the shell 52, so that the circulating material inlet 591 and the circulating material outlet 592 are only communicated with each other in the shell 52 through the second material mixing unit in a fluid mode, and the circulating material outlet 592 and the circulating material inlet 591 are only communicated with each other in the material circulating pipeline 59 through the first material mixing unit in a fluid mode; the raw material inlet 1 is communicated with a feed inlet 51 of the mixing reaction equipment, a discharge outlet 58 of the mixing reaction equipment is communicated with an inlet of the solid-liquid separation equipment, and a liquid outlet and a solid outlet of the solid-liquid separation equipment are respectively communicated with a sewage outlet 8 and a concentrated sludge outlet 9.

The system for treating the residual biochemical sludge can realize the external circulation mixing and the internal intensified mixing by arranging the external circulation pipeline with the mixing unit on the mixed reaction equipment, improve the mixing efficiency of the sludge and be beneficial to the sludge reduction reaction. The system has simple structure, convenient operation and convenient popularization and application.

According to the present disclosure, the shape of the mixing reaction apparatus may be conventional in the art, without particular limitation, for example, the housing 52 may be cylindrical or tubular, for example, the housing 52 may be vertical or horizontal; in one embodiment of the present disclosure, as shown in fig. 2, the housing 52 may be a vertical cylinder, and the inlet 51 and the outlet 58 may be located at the bottom and the top of the housing 52, respectively. In the embodiment, the mixing space in the equipment is large, so that the sludge raw material can flow through the mixing reaction equipment from bottom to top and is fully mixed and reacted by the first material mixing unit and the second material mixing unit inside and outside the shell, and the mixing effect is enhanced. In another embodiment, the inlet 51 and outlet 58 may be located at the top and bottom of the housing 52, respectively.

According to the present disclosure, the number of the second material mixing units may be one or more, in order to enhance the material mixing effect inside the equipment, the number of the second material mixing units is preferably 2-6, and the plurality of second material mixing units may be axially arranged in the housing 52 at intervals, so that the material sequentially flows through the plurality of second material mixing units for multiple mixing distribution.

Further, in order to facilitate the material entering the material circulation line 59, the circulation material outlet 592 may be disposed on the sidewall of the housing below the material outlet 58, and the circulation material inlet 591 may be disposed on the sidewall of the housing above the material inlet 51.

In one embodiment of the present disclosure, the first mixing unit and the second mixing unit may be static mixing units, for example, static mixers, respectively, so as to avoid a special mechanical mixing device in the housing and prevent leakage of the dynamic seal.

In order to further enhance the mixing enhancement effect, in an embodiment of the present disclosure, as shown in fig. 1, the second material mixing unit may include a first partition 510 and a mixing distribution assembly 55, the first partition 510 is radially disposed inside the housing 52, an edge of the first partition 510 may be hermetically connected to an inner wall of the housing 52 to divide the inside of the housing 52 into a first mixing reaction chamber and a second mixing reaction chamber from bottom to top, i.e., the first mixing reaction chamber and the second mixing reaction chamber are respectively formed at both sides of the first partition 510, the feed inlet 51 and the discharge outlet 58 may be respectively communicated with the first mixing reaction chamber and the second mixing reaction chamber, so that the sludge inside the housing 52 sequentially flows through the first mixing reaction chamber and the second mixing reaction chamber, the circulating material inlet 591 and the circulating material outlet 592 may be respectively communicated with the first mixing reaction chamber and the second mixing reaction chamber, so that part of the sludge in the second mixing reaction chamber returns to the first mixing reaction chamber through a material circulating pipeline 59, thereby forming a material circulating path; the mixing and distributing assembly 55 can be fixedly connected with the first partition plate 510, and the inlet of the mixing and distributing assembly 55 can penetrate through the first partition plate 510, and the outlet can be communicated with the second mixing and reacting chamber, so that the first mixing and reacting chamber and the second mixing and reacting chamber are communicated only through the mixing and distributing assembly 55, that is, the sludge in the first mixing and reacting chamber enters the second mixing and reacting chamber after all entering the mixing and distributing assembly 55, and the mixing efficiency is improved. In this embodiment, the raw material containing the excess biochemical sludge and the auxiliary agent enters the first mixing reaction chamber from the feeding hole 51, is primarily mixed, and then enters the second mixing reaction chamber after being mixed by the mixing distribution assembly 55 disposed on the first partition plate, and a part of the mixed material in the second mixing reaction chamber enters the material circulation pipeline 59 from the circulating material outlet 592, is mixed by the first material mixing unit 57, and then circulates to the circulating material inlet 591 to return to the first mixing reaction chamber, and is mixed and reacted with the material entering the first mixing reaction chamber.

The first partition 510 may be a flat plate, a corrugated plate, or an arc plate, and is preferably a flat plate; the edge of the first barrier 510 may be sealingly connected with the inner wall of the housing to divide the interior space of the housing into a first mixing reaction chamber and a second mixing reaction chamber.

Further, in order to improve the mixing effect of the second material mixing unit, in one embodiment of the present disclosure, as shown in fig. 3, the mixing distribution assembly 55 may be disposed on the first partition 510 along the axial direction of the housing, so that the sludge flow direction in the housing is consistent with the sludge flow direction in the mixing distribution assembly 55; further, in order to facilitate the sludge mixing reaction and uniform distribution, as shown in fig. 3-5, the mixing and distributing assembly 55 may include a second static mixer 551 and a distributor 552 which are sequentially communicated, an inlet of the second static mixer 551 may be communicated with an inlet of the mixing and distributing assembly 55, that is, an inlet of the second static mixer 551 penetrates through the first partition 510, and an outlet of the distributor 552 may be communicated with an outlet of the mixing and distributing assembly 55, that is, an outlet of the distributor 552 is communicated with the second mixing reaction chamber, so that the sludge entering the mixing and distributing assembly 55 flows through the second static mixer 551 for mixing and then enters the distributor 552 for distribution, thereby improving the uniformity of the material flow mixing in the housing. Further, in order to optimize the mixing effect, the height of the mixing and distributing assembly 55 may not exceed 1/2, preferably 1/10 ~ 1/3.

In order to improve the distribution uniformity of the material in the radial direction of the mixing reaction equipment, in one embodiment of the present disclosure, as shown in fig. 2, the second static mixer 551 may be a tubular static mixer, the distributor 552 may be formed as a distribution pipe that is arranged coaxially and has the same diameter as the second static mixer 551, the bottom end of the distribution pipe is open to communicate with the second static mixer 551, the top end of the distribution pipe is closed, and the pipe wall of the distribution pipe may be formed with a plurality of distribution holes that are uniformly distributed around the circumference to form an outlet of the distributor 552. The tubular static mixer can be one or more of SV type, SK type, SX type, SL type, SH type and other types of static mixers meeting the requirements of standards (such as JB/T7660-2016); the dispensing aperture may be formed in at least one of a bar shape (fig. 4), a triangle shape, a circle shape (fig. 5), and an oval shape. In this embodiment, the material flows in the second static mixer 551 along the axial direction for mixing reaction, and then enters the distribution pipe to enter the second mixing reaction chamber after being distributed by the distribution holes, and since the opening direction of the distribution holes is perpendicular to the axial direction of the mixing distribution assembly 55, on one hand, the mixed material can be uniformly distributed in the radial direction of the shell, and on the other hand, the improvement of the turbulence degree of the fluid and the mixing effect between different streams of fluid are facilitated, thereby facilitating the implementation of the sludge reduction reaction.

According to the present disclosure, in order to improve the sludge mixing and digestion reaction efficiency in the mixing reaction equipment and ensure uniform distribution of the materials in the radial direction, in one embodiment of the present disclosure, the second material mixing unit may include a first partition plate 10 and a plurality of mixing and distributing assemblies 55, and the plurality of mixing and distributing assemblies 55 may be uniformly distributed on the first partition plate 510, so that the mixed sludge on the radial section of the housing uniformly enters the second material mixing unit for mixing, thereby improving the mixing efficiency and the distribution effect. The arrangement of the plurality of mixing and dispensing assemblies 55 may be conventional in the art, such as forming a triangular or square array.

According to the present disclosure, in order to enhance the mixing reaction effect of the excess biochemical sludge in the mixing reaction equipment and promote the digestion reaction, in one embodiment, as shown in fig. 1 and 2, the second material mixing unit may further include a collecting device disposed in the first mixing reaction chamber for collecting the material in the first mixing reaction chamber and making the material flow to the inlet of the second material mixing unit; further, the collecting means may include a second partition 511 spaced apart from and parallel to the first partition 510, an edge of the second partition 511 may be sealingly coupled to an inner wall of the housing 52 to form a buffer distribution chamber between the first partition 510 and the second partition 511, and a through hole may be formed in the second partition 511 to communicate the buffer distribution chamber with the first mixing reaction chamber. In this embodiment, the materials in the first mixing reaction chamber can enter the buffering distribution chamber through the through holes after being primarily mixed, and then enter the second mixing reaction chamber after being uniformly distributed in the radial direction and mixed by the second material mixing unit, so that the mixing and distribution effects are enhanced. Further, in order to improve uniformity of radial distribution, a through hole may be provided at the center of the second partition 511. In other embodiments of the present disclosure, the collecting device may include two arc-shaped plates staggered at an axial interval, so as to generate a baffled flow perpendicular to the axial direction of the housing before the sludge material enters the second material mixing unit.

In the embodiment where the collecting device includes the second partition 511, in order to further enhance the mixing and reducing reaction of the sludge and the auxiliary agent, as shown in fig. 3, further, the collecting device may further include a guide cylinder 54, the guide cylinder 54 may be fixed on the outer side of the buffer distribution chamber and cover the through hole, that is, the guide cylinder 54 may be fixed on the side of the second partition 511 away from the first partition 510, and the side wall of the cylinder of the guide cylinder 54 may have an opening to form an inlet of the collecting device; the shape of the opening is not limited, and the opening can be at least one of rectangular, circular, triangular, trapezoidal and spiral. In this embodiment, when the material in the first mixing reaction chamber flows to the guide shell along the axial direction, the material can enter the guide shell 54 along the radial direction through the openings of the collecting device and flow from the periphery to the center of the guide shell, and the turbulence degree of the mixed sludge can be improved by changing the flow direction, thereby being beneficial to the mixing and reducing reaction.

Further, in order to sufficiently mix the mixed fluid entering the guide shell 54 and then enter the buffer distribution chamber, in an embodiment of the present disclosure, the through hole may be located at the center of the second partition 511, and the second partition 511 and the guide shell 54 may be coaxially disposed. At this time, the flow distribution of the mixed material of the sludge and the auxiliary agent in each direction in the guide shell 54 and the buffer distribution chamber is more uniform, which is beneficial to mixing.

In the embodiment that the collecting device comprises the guide shell 54, further, in order to facilitate collecting the material, the openings on the side wall of the cylinder body can be multiple and arranged at equal intervals along the circumferential direction of the cylinder body, so that the material in the first mixing reaction chamber can flow into the guide shell 54 from the openings in multiple different directions, the mixing efficiency is improved, and multiple streams of fluid entering the guide shell 54 can further collide and contact to enhance the mixing and reaction effects.

In the embodiment where the collecting device includes the flow guiding cylinder 54, further, in order to enhance the mixing effect, in one embodiment of the present disclosure, as shown in fig. 3, a plurality of deflecting sleeves may be disposed inside the flow guiding cylinder 54 and coaxially spaced apart from each other to form a deflecting channel inside the flow guiding cylinder 54, so that the material can be deflected to flow from the periphery to the center of the flow guiding cylinder in the radial direction, for example, the deflecting sleeves may include an upper deflecting sleeve and a lower deflecting sleeve that are coaxially spaced apart from each other, a top end of the upper deflecting sleeve may be fixed to the second partition 511, and a bottom end of the upper deflecting sleeve may be spaced apart from the bottom wall of the flow guiding cylinder 54, and a bottom end of the lower deflecting sleeve may be fixed to the bottom wall of the flow guiding cylinder 54, and a top end of the lower deflecting sleeve may be spaced apart from the second partition 511, so that the material entering the flow guiding cylinder 54 is deflected from the periphery to the center. In another embodiment of the present disclosure, a mixing filler may be disposed in the guide shell 54 to improve the flow mixing and reaction efficiency of the materials.

In order to achieve sufficient mixing effect of the recycled materials and the sludge and the auxiliary agents in the first mixing reaction chamber, in one embodiment of the present disclosure, as shown in fig. 1, the mixing reaction apparatus may further include a fluid distribution device 53 disposed in the first mixing reaction chamber, an inlet of the fluid distribution device 53 may be communicated with the recycled material inlet 591, and an outlet of the fluid distribution device 53 may be communicated with the first mixing reaction chamber and faces the feed inlet 51, so that the recycled materials and the raw materials flowing in from the feed inlet 51 are more sufficiently mixed.

The fluid distribution means 53 may be of a conventional kind in the art in accordance with the present disclosure, and in order to further enhance the dispersion effect, the fluid distribution means 53 may be selected from at least one of a pipe distributor, a trough distributor, a disc distributor, an impingement distributor, a nozzle distributor, a pagoda distributor, and a shower distributor. The fluid distribution device of the above type has a large pressure drop, can ensure that the circulating material has sufficient outlet linear speed when entering the first mixing reaction chamber, and is favorable for mixing and reaction. Further, the recycled material outlet of the fluid distribution means 53 is directed downward to promote thorough mixing of the recycled material with the feed material.

According to the present disclosure, to prevent the dynamic seal leakage problem generated by the dynamic mixing component, the first material mixing unit 57 may be a static mixer. Further, in order to connect the material circulation line, in one embodiment of the present disclosure, the first material mixing unit 57 may include a single-pipe static mixer and/or a shell and tube static mixer. The single-tube static mixer can be selected from SV type, SK type, SX type, SL type, SH type and other types of static mixers meeting the standard requirements, the tubular static mixer can be a plurality of single tubes which are uniformly distributed in a shell to form a whole, and the distribution mode can be triangular or square arrangement. For a shell-and-tube static mixer, the circulating material can pass through the tube side, and a heating or cooling medium can be further selectively introduced into the shell side to achieve the effect of controlling the temperature in the reactor.

In order to promote the circular mixing of the materials in the material circulation pipeline, in one embodiment of the present disclosure, as shown in fig. 2, a circulation pump 56 may be connected to the material circulation pipeline 59, and the circulation pump 56 may be disposed between the circulation material outlet 592 and the first material mixing unit 57. The circulation pump 56 may be of a type conventional in the art, such as a pipe centrifugal pump.

The solid-liquid separation apparatus, in accordance with the present disclosure, may be of a type conventional in the art. In order to further improve the effect of performing solid-liquid separation on the offset reaction product, in one embodiment of the present disclosure, as shown in fig. 1, the solid-liquid separation equipment may include a cyclone 6 and a settling tank 7, an inlet of the cyclone 6 may be communicated with a discharge port of the mixing reaction equipment, a liquid outlet of the cyclone 6 may be communicated with a sewage outlet 8, a solid outlet of the cyclone 6 may be communicated with an inlet of the settling tank 7, and a liquid outlet and a solid outlet of the settling tank 7 may be respectively communicated with the sewage outlet 8 and a concentrated sludge outlet 9. In this embodiment, most of the water is separated from the material by the cyclone separator 6, and the separated solid phase is further settled, dehydrated and concentrated by the settling tank 7, and finally the concentrated sludge with greatly reduced water content is obtained.

In another embodiment of the present disclosure, the solid-liquid separation equipment may include a settling tank, the upper part of the tank body of the settling tank may be provided with a cyclone separator, i.e., the cyclone separator may be placed inside the gravity settling tank as a combined device to save equipment space and transport power, the inlet of the cyclone separator may pass through the settling tank and communicate with the discharge port of the hybrid reaction equipment, the solid outlet of the cyclone separator communicates with the inside of the tank body of the settling tank, the liquid outlets of the cyclone separator and the settling tank communicate with the sewage outlet, respectively, and the solid outlet of the settling tank communicates with the concentrated sludge outlet.

According to the present disclosure, the auxiliary agent for performing the sludge digestion reaction may enter the mixing reaction device 5 together with the excess biochemical sludge, and in one embodiment of the present disclosure, the system may further include an auxiliary agent inlet 2, and the auxiliary agent inlet 2 may be communicated with the feed port 51 of the mixing reaction device, so that the auxiliary agent and the biological biochemical sludge enter the mixing reaction device from the auxiliary agent inlet 2 and the raw material inlet 1, respectively, so as to separately control the feeding amount of the two. In other embodiments, the adjunct and excess biochemical sludge may be introduced into the system from the feedstock inlet 1.

In one embodiment of the present disclosure, to facilitate feeding, the system may include a feed pump 3, and the feed pump 3 may be disposed between the raw material inlet 1 and the mixing reaction device 5.

In order to facilitate the improvement of the efficiency of the sludge reduction reaction in the hybrid reaction device, in one embodiment of the present disclosure, the system may include a heat exchanger 4 for exchanging heat with the raw material entering the system, and the heat exchanger 4 may be disposed between the raw material inlet 1 and the hybrid reaction device 5.

A second aspect of the present disclosure provides a method for treating excess biochemical sludge using the system according to the first aspect of the present disclosure. The method is simple to operate and convenient to apply.

As shown in fig. 1, in one embodiment of the present disclosure, a method of performing a treatment reaction on excess biochemical sludge material in a system of the present disclosure may include: the residual biochemical sludge raw material and the auxiliary agent respectively enter the system from a reaction raw material inlet 1 and an auxiliary agent inlet 2, enter a feed inlet 1 of a mixing reaction device 5 after being boosted by a feed pump 3 and heat exchanged by a heat exchanger 4, enter a first mixing reaction chamber and are primarily mixed with the circulating material flowing out of a fluid distribution device 53, enter a guide cylinder 54 from an opening on the side wall, axially flow from the periphery to the center under the action of a deflection sleeve, enter a buffering distribution chamber through a through hole on a second partition plate for the material in the center of the guide cylinder 54, uniformly distribute in the radial direction and enter a second material mixing unit arranged on the first partition plate, the material firstly flows upwards in a second static mixer 551 along the axial direction for mixing reaction, then enter a distribution pipe and are distributed by distribution holes to enter a second mixing reaction chamber for further mixing, and part of the material in the second mixing reaction chamber enters a material circulation material outlet 592 into a material circulation pipeline 59, the rest materials are extracted from a material outlet 58 at the top, and the circulating materials are mixed by a first material mixing unit 57, circulated to a circulating material inlet 591, enter a fluid distribution device 53, return to the first mixing reaction chamber after being uniformly distributed, and are mixed and reacted with the materials entering the first mixing reaction chamber. The reaction product extracted from the discharge port 58 at the top of the mixing reaction equipment 5 enters the cyclone separator 6 to remove most of water, the separated solid phase is further settled, dehydrated and concentrated by the settling tank 7, the concentrated sludge with greatly reduced water content is finally obtained from the concentrated sludge outlet 9, and the sewage separated by the cyclone separator 6 and the settling tank 7 flows out through the sewage outlet 8.

A third aspect of the present disclosure provides a method for treating excess biochemical sludge, the method comprising the steps of: s1, under the condition of the reduction reaction, the residual biochemical sludge and the auxiliary agent are subjected to the reduction reaction in the mixed reaction equipment to obtain a reduction reaction product; s2, mixing at least part of the mixed materials in the mixed reaction equipment as circulating materials outside the mixed reaction equipment, and returning the mixed materials to the mixed reaction equipment; s3, carrying out solid-liquid separation on the products of the reduction reaction to respectively obtain sewage and concentrated sludge.

According to the method, the reduction reaction raw materials are subjected to external circulation mixing and internal intensive mixing at the same time, so that the sludge liquid-solid heterogeneous system can be efficiently mixed, and the reduction reaction is favorably carried out. The method has the advantages of convenient operation, mild conditions, cheap and easily obtained reagents and the like, and is convenient for popularization and application.

In accordance with the present disclosure, the conditions under which the excess biochemical sludge is subjected to the abatement reaction may vary over a wide range, with preferred abatement reaction conditions including: the reaction temperature can be 80-300 ℃, and is preferably 100-250 ℃; the reaction pressure can be 0.05MPa to 10.0MPa, and preferably 0.1MPa to 5.0 MPa; the addition amount of the auxiliary agent can be such that the pH value of the mixed material in the mixed reaction equipment is 8-14, and preferably 10-13; the retention time of the residual biochemical sludge in the mixed reaction equipment can be 0.1-6.0 h, and preferably 0.5-4.0 h.

According to the disclosure, the excess biochemical sludge to be treated may be municipal sludge or industrial sludge, and the solid content may be 1 to 10 wt%.

According to the present disclosure, the auxiliary agent may be a conventional auxiliary agent for performing a sludge digestion reaction, and is preferably an alkaline auxiliary agent, and further, the alkaline auxiliary agent is preferably at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium oxide, sodium peroxide, potassium oxide, potassium peroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

According to the present disclosure, the ratio of the circulating material circulating in the pipeline to the feeding amount of the raw material may be varied within a wide range, and in order to further improve the mixing reaction effect, the mass flow ratio of the circulating material to the feeding amount of the surplus biochemical sludge may be 0.5 to 5.0, preferably 1.0 to 3.0.

According to the present disclosure, the method for performing solid-liquid separation may be conventional in the art, such as settling separation, centrifugal separation, and the like, and preferably, in order to improve the separation efficiency, the solid-liquid separation in the method of the present disclosure may sequentially include cyclone separation and gravity settling, so that most of the water in the material is separated by cyclone separation, and the separated solid phase is further dehydrated and concentrated by gravity settling, so as to finally obtain the concentrated sludge with greatly reduced water content. The equipment and operating methods for carrying out the cyclonic separation and gravity settling may be conventional in the art and will not be described further herein. The concentrated sludge obtained after gravity settling can be further subjected to dehydration concentration treatment.

The mixing reaction apparatus of the present disclosure is further illustrated below by examples, but the present disclosure is not limited thereto. The experimental raw material in the following examples and comparative examples was excess biochemical sludge (solid content: 2.25 w%) from a municipal sewage treatment plant of Tianjin, and 30% sodium hydroxide solution was used as the alkaline auxiliary. The change conditions of the suspended solids SS in the raw materials and the treated materials before and after the reaction are mainly considered, the SS analysis method is carried out according to the national standard GB 11901-89, and the analysis results of the raw materials are shown in Table 1.

Examples

This example is intended to demonstrate the effectiveness of the disclosed systems and methods for treating excess biochemical sludge in a abatement process for a sludge feedstock.

As shown in fig. 1 and fig. 2, the mixing reaction device in the excess biochemical sludge treatment system of this embodiment is separated into a first mixing reaction chamber and a second mixing reaction chamber, the raw materials are fed in and out from the first mixing reaction chamber, the pH of the fed materials is adjusted to 13 by adding alkali liquor, the inlet temperature of the mixing reaction device is 180 ℃, the outlet pressure of the mixing reaction device is 1.5MPa, and the apparent retention time of the materials in the mixing reaction device is 2 h. The bottom of the mixing reaction equipment is provided with a calandria type high pressure drop distributor, and the bottom of the branch pipe is provided with a certain number of round hole channels. Be three SK type static mixer that triangle-shaped arranged on the first baffle, leave one section distributing pipe at the blender top, the distributing pipe lateral wall symmetry is opened has four bar passageways, and bar size 1mm 4mm, the blender total length accounts for 1/4 of first baffle overall height. The circulation ratio is 1.5, the circulating pump is a centrifugal pump, a shell and tube mixer is arranged on the material circulating pipeline, and three mixing pipes are arranged in a triangular shape and are also SK type mixing elements. The experiment shows that the pressure drop of the high pressure drop distributor in the reactor is 0.36MPa, the pressure drop of the internal mixer (the second mixed reaction unit) is 0.22MPa, and the pressure drop of the external mixer (the first mixed reaction unit) is 0.19 MPa. The reactor outlet material was taken for analysis and the results are shown in table 1. The materials at the outlet of the reactor are subjected to liquid-solid separation through a liquid-solid cyclone, the sludge extracted from the bottom of the cyclone enters a gravity settling tank for further separation, the supernatant at the top is mixed with the supernatant discharged from the settling tank and then extracted, the retention time at the bottom of the settling tank is 10min, and the result of the water content of the sludge extracted from the tank bottom is shown in table 2.

Comparative example

The comparative example uses a conventional mechanical stirred tank reactor to treat the municipal sludge raw material, and the reaction raw materials are the same as those in the example. To the sludge feed was added a certain amount of sodium hydroxide solution, controlling the feed pH at 13. The rotation speed of the stirred tank is 200rpm, the reaction temperature is controlled by heating to be 180 ℃, the pressure of the reactor is 1.5MPa, and the reaction residence time is 2h^-1. The amount of excess sludge in the reacted material was analyzed and the results are shown in Table 1. The materials at the outlet of the reactor are subjected to gravity settling for 10min, and the water content result of the sludge extracted from the bottom of the tank is shown in Table 2.

TABLE 1

Item	Starting materials	Comparative example	Examples
				SS content, g/L	22.53	9.92	9.86

TABLE 2

Item	Comparative example	Examples
			Water content of tank bottom sludge, w%	68	59

As can be seen from the data in tables 1 and 2, the system and method for treating excess biochemical sludge of the present disclosure is more efficient and effective in sludge abatement and also has less water content in the concentrated sludge product.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that the various features described in the foregoing embodiments may be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the disclosure does not separately describe various possible combinations.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure as long as it does not depart from the gist of the present disclosure.

Claims

1. The system for treating the residual biochemical sludge is characterized by comprising a raw material inlet (1), a mixed reaction device (5), a solid-liquid separation device, a sewage outlet (8) and a concentrated sludge outlet (9);

the mixing reaction device (5) comprises a shell (52) with a feeding hole (51) and a discharging hole (58), a material circulating pipeline (59) is arranged outside the shell (52), the material circulating pipeline (59) is communicated with the interior of the shell (52) through a circulating material inlet (591) and a circulating material outlet (592) respectively, a first material mixing unit (57) is connected onto the material circulating pipeline (59), a second material mixing unit is arranged in the shell (52), so that the circulating material inlet (591) and the circulating material outlet (592) are communicated with each other only through the second material mixing unit in the shell (52), and the circulating material outlet (592) and the circulating material inlet (591) are communicated with each other only through the first material mixing unit in the material circulating pipeline (59); wherein the first material mixing unit (57) and the second material mixing unit are static mixing units, respectively;

The raw material inlet (1) is communicated with the feed inlet (51) of the mixed reaction equipment (5), the discharge outlet (58) of the mixed reaction equipment (5) is communicated with the inlet of the solid-liquid separation equipment, and the liquid outlet and the solid outlet of the solid-liquid separation equipment are respectively communicated with the sewage outlet (8) and the concentrated sludge outlet (9).

2. The system according to claim 1, wherein the housing (52) of the mixing reaction device (5) is a vertical cylinder, the number of the second material mixing units is one or more, and a plurality of the second material mixing units are arranged in the housing (52) at intervals along the axial direction.

3. The system of claim 1, wherein the second material mixing unit comprises a first baffle (510) and a mixing and dispensing assembly (55);

the first clapboard (510) is arranged inside the shell (52) along the radial direction, the edge of the first clapboard (510) is connected with the inner wall of the shell (52) in a sealing way so as to divide the inside of the shell (52) into a first mixing reaction chamber and a second mixing reaction chamber from bottom to top, the mixing distribution component (55) is fixedly connected with the first clapboard (510), and the inlet of the mixing distribution component (55) penetrates through the first clapboard (510) and the outlet is communicated with the second mixing reaction chamber, so that the first mixing reaction chamber is communicated with the second mixing reaction chamber only through the mixing distribution component (55);

The feed inlet (51) and the recycled material inlet (591) are respectively communicated with the first mixing reaction chamber, and the discharge outlet (58) and the recycled material outlet (592) are respectively communicated with the second mixing reaction chamber.

4. The system according to claim 3, characterized in that the mixing and distributing assembly (55) is arranged on the first partition (510) along the axial direction of the housing (52), the mixing and distributing assembly (55) comprises a second static mixer (551) and a distributor (552) which are communicated in sequence, the inlet of the second static mixer (551) penetrates through the first partition (510), and the outlet of the distributor (552) is communicated with the second mixing and reacting chamber.

5. The system according to claim 4, characterized in that the second static mixer (551) is a tubular static mixer, the distributor (552) is formed as a distributor tube coaxial with the second static mixer (551) in a constant diameter, the bottom end of the distributor tube is open to communicate with the outlet of the second static mixer (551), the top end of the distributor tube is closed, and the wall of the distributor tube is formed with a plurality of distribution holes evenly distributed around the circumference to form the outlet of the distributor (552).

6. The system according to claim 3, wherein said second material mixing unit comprises one said first partition (510) and a plurality of said mixing and distributing elements (55), said plurality of mixing and distributing elements (55) being evenly distributed over said first partition (510).

7. The system of claim 3, wherein the second material mixing unit further comprises a collection device disposed within the first mixing chamber;

the collecting device comprises a second partition plate (511) which is arranged in parallel with the first partition plate (510) at a certain interval, the edge of the second partition plate (511) is connected with the inner wall of the shell (52) in a sealing way, so that a buffer distribution chamber is formed between the first partition plate (510) and the second partition plate (511), and a through hole is formed in the second partition plate (511) so as to communicate the buffer distribution chamber with the first mixing reaction chamber.

8. The system according to claim 7, wherein the collecting device further comprises a guide shell (54), the guide shell (54) is fixed outside the buffer distribution chamber and covers the through hole, and a cylindrical side wall of the guide shell (54) is provided with an opening to form an inlet of the collecting device.

9. The system according to claim 8, characterized in that said through hole is located in the center of said second partition (511), said second partition (511) and said guide shell (54) being coaxially arranged.

10. The system of claim 8, wherein the openings are a plurality of and equally spaced around the circumference of the cylinder of the draft tube (54).

11. The system of claim 8, wherein a plurality of coaxially spaced baffle sleeves are provided within the baffle cartridge (54) to form baffle passages within the baffle cartridge (54); or mixed filler is arranged in the guide shell (54).

12. The system according to claim 1, wherein the mixing reaction device (5) further comprises a fluid distribution device (53) arranged in the first mixing reaction chamber, an inlet of the fluid distribution device (53) being in communication with the recycled material inlet (591), and an outlet of the fluid distribution device (53) being in communication with the first mixing reaction chamber and facing the feed inlet (51).

13. The system according to claim 12, wherein the fluid distribution means (53) is selected from a tube distributor, a trough distributor, a disc distributor, an impingement distributor, a nozzle distributor, a pagoda distributor or a shower distributor, or a combination of two or three or four thereof.

14. The system according to any one of claims 1 to 13, characterized in that the first material mixing unit (57) comprises a single-tube static mixer and/or a shell-and-tube static mixer.

15. The system according to claim 1, characterized in that a circulation pump (56) is connected to the material circulation line (59), the circulation pump (56) being arranged between the circulating material outlet (592) and the first material mixing unit (57).

16. The system according to claim 1, characterized in that the solid-liquid separation equipment comprises a cyclone separator (6) and a settling tank (7), wherein the inlet of the cyclone separator (6) is communicated with the discharge port (58) of the mixing reaction equipment (5), the liquid outlet of the cyclone separator (6) is communicated with the sewage outlet (8), the solid outlet of the cyclone separator (6) is communicated with the inlet of the settling tank (7), and the liquid outlet and the solid outlet of the settling tank (7) are respectively communicated with the sewage outlet (8) and the concentrated sludge outlet (9).

17. The system according to claim 1, characterized in that the solid-liquid separation equipment comprises a settling tank (7), a cyclone separator (6) is arranged at the upper part of the settling tank (7), the inlet of the cyclone separator (6) penetrates through the settling tank (7) and is communicated with the discharge hole (58) of the mixing reaction equipment (5), the solid outlet of the cyclone separator (6) is communicated with the inside of the settling tank (7), the liquid outlets of the cyclone separator (6) and the settling tank (7) are respectively communicated with the sewage outlet (8), and the solid outlet of the settling tank (7) is communicated with the concentrated sludge outlet (9).

18. A system according to claim 1, characterized in that the system further comprises an auxiliary agent inlet (2), said auxiliary agent inlet (2) being in communication with the feed opening (51) of the mixing reaction device (5).

19. A system according to claim 1, characterized in that it comprises a feed pump (3), said feed pump (3) being arranged between said feedstock inlet (1) and said mixing and reaction device (5).

20. The system according to claim 1, characterized in that it comprises a heat exchanger (4), said heat exchanger (4) being arranged between said feedstock inlet (1) and said mixing reaction device (5).

21. A method for treating excess biochemical sludge, characterized in that the system of any one of claims 1 to 20 is used, and the method comprises the following steps:

22. The method of claim 21, wherein the abatement reaction conditions comprise: the reaction temperature is 80-300 ℃; the reaction pressure is 0.05MPa to 10.0 MPa; the addition amount of the auxiliary agent is such that the pH value of the mixed material in the mixed reaction equipment is 8-14; the retention time of the residual biochemical sludge in the mixed reaction equipment is 0.1-6.0 h.

23. The method of claim 21, wherein the solid content of the excess biochemical sludge is 1 w% to 10 w%.

24. The method of claim 21, wherein the auxiliary agent is a basic auxiliary agent selected from at least one of sodium hydroxide, potassium hydroxide, sodium oxide, sodium peroxide, potassium oxide, potassium peroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

25. The method as claimed in claim 21, wherein the mass flow ratio of the recycled material to the feed amount of the excess biochemical sludge is 0.5 to 5.0.

26. The method of claim 21, wherein the solid-liquid separation comprises a cyclonic separation and gravity settling in that order.