CN104098240B - Sewage sludge treatment plant - Google Patents

Abstract

The invention discloses a kind of sewage sludge treatment unit, comprise filter-pressing device 1, shredder assembly 2 and drying installation 3, this device also comprises mud freezing container 4 and lyophilize Power Cycle, the second vaporizer 8 that lyophilize Power Cycle comprises compressor 5, first vaporizer 6, condenser 7 and is arranged in mud freezing container, the outlet side of compressor is connected with condenser, condenser is connected with the first vaporizer through throttling element, and the first vaporizer is connected with the inlet end of compressor through the second vaporizer; Described condenser is connected with bottom drying installation by gas pipeline 10, and the first vaporizer is connected with drying installation top with by gas pipeline, and condenser is connected by gas pipeline with the first vaporizer simultaneously.The present invention adds chemicals without in mud, and treating processes can not increase mud handling capacity, and the recycle of working medium energy substantially increases freezing efficiency and the heat utilization ratio of mud.

Description

Sewage sludge treatment plant

technical field

The invention relates to the field of sewage sludge treatment, in particular to a sewage sludge treatment device.

Background technique

A large amount of sludge is produced in the process of sewage treatment, which accounts for about 0.3%-0.5% of the treated water. The investment and operation cost of sludge treatment are very huge, and the cost of sludge treatment generally accounts for 20% of the operating cost of sewage treatment plants. %-50%, bringing a heavy burden to sewage treatment. Sludge dehydration is a key link in sludge treatment, and it is of great significance to the subsequent drying, transportation, landfill, and resource utilization of sludge. The key to sludge dewatering is to improve the dewatering performance of sludge. The current traditional treatment method is to condition it first by adding flocculant, and then perform mechanical dehydration by filter press to form sludge with a moisture content of about 60% and transport it to landfill. , fermented fertilizer, etc. The pretreatment method of adding flocculant is to reduce the affinity between sludge and water through the flocculation of flocculant, change the existence form of water in sludge, neutralize the opposite charge in sewage, compress the electric double layer, and The destabilized coagulated particles play the role of adsorption and bridging, making them quickly form large flocs, so that the colloids can be destabilized and coagulated to achieve solid-liquid separation. The dosage of flocculant is calculated as a percentage of the dry weight of sludge solids, and the dosage of different flocculants will be different. Although the dewatering performance of sludge can be significantly improved by adding flocculants, due to the need for a large amount of flocculants, not only the cost of sludge treatment will be increased, but also a large amount of flocculants will be added to the dehydrated sludge, increasing the sludge treatment volume. Other pretreatment methods, such as ultrasonic treatment, consume a lot of heat and need to add ultrasonic treatment devices; the use of biological methods and thermodynamic methods requires the consumption of biological agents and heat.

The freezing method is used to pre-treat the sludge. After the sludge is repeatedly frozen, it can destroy the binding force between the sludge and water and the structure of the colloid (similar to the built-in tofu after freezing), so that the colloid is destabilized and coagulated and the cell membrane is broken. The water inside the cells that is difficult to remove by mechanical means is dialyzed to form interstitial water that is easy to remove by mechanical means. The sludge particles settle rapidly, and the dehydration speed is dozens of times higher than that before freezing. Using the freezing method does not require adding chemicals, which can save the cost of chemicals. And it will not increase the amount of sludge treatment in the later stage, and combined with the subsequent treatment method of sludge, the deep reduction treatment of sludge will be completed.

However, in the prior art, the freezing of sludge mainly relies on the natural environment, that is, the sludge is placed outdoors in cold weather and depends on the natural environment to cool down to about -10°C for freezing and thawing, but this process has low efficiency and takes a long time. problems, and if it is not possible to operate in the southern region or in non-winter conditions, the natural conditions are more demanding. In addition, in the prior art, using external force to freeze and thaw sludge requires dual energy for cooling and heating the sludge, and the cost is very high, so it is difficult to popularize and apply.

Contents of the invention

In view of this, the present invention aims at the problems in the above-mentioned prior art that increasing the flocculant will increase the sludge treatment capacity, low freezing efficiency and high cost, and provides a treatment process that does not increase the sludge handling capacity, has high freezing efficiency and Sewage sludge treatment device with high energy utilization rate.

The technical solution of the present invention is to provide a sewage sludge treatment device with the following structure, including a filter press device, a crushing device and a drying device. After the mud is crushed, it enters the drying device for drying treatment;

The sewage sludge treatment device also includes a sludge freezing container and a freeze-drying energy circulation system, and the freeze-drying energy circulation system includes a compressor, a first evaporator, a condenser, and a first Two evaporators, the outlet end of the compressor is connected to the condenser, the condenser is connected to the first evaporator through a throttling element, and the first evaporator is connected to the inlet end of the compressor through the second evaporator; the condenser The gas pipeline communicates with the bottom of the drying device, the first evaporator communicates with the top of the drying device through the gas pipeline, and the condenser communicates with the first evaporator through the gas pipeline.

With the above structure, compared with the prior art, the present invention has the following advantages: by adopting the present invention, the freeze-drying energy circulation system is utilized, and at the same time, the freezing of the sludge in the sludge freezing container and the drying of the sludge in the drying device are realized. Under the action of the compressor, the working medium outputs high-temperature and high-pressure gaseous working medium. After passing through the condenser, the heat in the working medium is absorbed by the air, and the heat is transferred to the air. The temperature of the air rises, the temperature of the working medium decreases, and the hot air passes through into the drying device to dry the material, the working medium is condensed into a high-pressure liquid, and the high-pressure liquid working medium becomes a low-pressure liquid working medium after being depressurized by the throttling element, and the low-pressure liquid working medium enters the first evaporator and absorbs the first The heat of the air in the evaporator (the air coming out from the top of the material) cools the air. After the saturated air cools down, the moisture it can hold decreases, and the excess moisture condenses into liquid water and is drained away through the water accumulation tray of the first evaporator. , the working fluid changes from a low-pressure liquid to a low-pressure gas after absorbing heat (if the working fluid does not absorb enough heat from the air, only part of the liquid working fluid can be evaporated into a gaseous working medium, and the remaining part of the liquid working medium and gaseous working medium Two-phase working fluid) enters the second evaporator, the working fluid absorbs the heat of the sludge in the second evaporator, and cools the sludge to the required freezing temperature -10°C ~ -15°C (this temperature range is better, But not limited to this numerical range), at this time, the liquid working medium is vaporized into a gaseous working medium, and the gaseous working medium enters the compressor. The sludge in the sludge freezing container has been frozen and thawed many times (thawing can be thawed naturally), which destroys the structure of the sludge, and the thawed sludge enters the filter press device, which presses the sludge into large cake-like sludge , and then sent to the crushing device for crushing to form sludge particles, and the sludge particles are dried in the drying device to realize the staged treatment of sludge. Since there is no need to add chemicals to the sludge, the treatment process will not increase the amount of sludge treated; the recycling of working medium energy greatly improves the freezing efficiency of sludge, and the working medium can freeze the sludge only by spending a small amount of compressor energy. The heat in the container that is several times the energy consumption of the compressor is "transferred" to the drying box, and the sludge is frozen and dried at the same time, which not only solves the source of cooling required for freezing, but also solves the source of heat required for drying, making cooling The energy and heat have reached a very good balance, greatly improving the efficiency of heat use, and the energy saving effect is obvious.

Preferably, there are multiple sludge freezing containers, and the second evaporator corresponds to the sludge freezing container one by one, and the two ends of the second evaporator in the multiple sludge freezing containers are connected to The first evaporator is connected to the compressor, the bottom of the sludge freezing container is provided with a filter structure, and the bottoms of multiple sludge freezing containers are connected to the filter press device through a liquid reversing valve and a liquid pipeline. In this way, when the sludge in one sludge freezing container is frozen, the sludge in other sludge freezing containers will be thawed naturally, and the thawed ones will be directly transported to the filter press device, thereby improving the treatment efficiency and enabling continuous Work.

Preferably, the drying device includes a drying box and a sludge turning mechanism, the sludge turning mechanisms are arranged horizontally at different vertical heights in the drying box, and the sludge turning mechanisms are staggered Arranged, a sludge turnover mechanism at the bottom layer protrudes out of the drying box. In this way, the sludge enters the drying device after being crushed, and first falls into the uppermost layer of the sludge turning mechanism. With the transmission of the sludge turning mechanism, the sludge falls on the sludge turning mechanism of the next layer, and The sludge turnover mechanism is then reversed and driven to the other end. This reciprocation can realize the contact between the hot air and the sludge up and down, all-round drying, and improve the drying effect. When it falls to the sludge turnover mechanism at the bottom layer, As it protrudes out of the drying box, the sludge is conveyed to the outside of the drying box and enters the next step of processing.

Preferably, the filter press device is a plate and frame filter press, the plate and frame filter press includes a plurality of plate frames, and a plate pulling mechanism is provided under the plate frames, and the plate pulling mechanism includes a plurality of traction blocks and sliding plates A hinged link is provided between two adjacent traction blocks, and rollers are provided under each traction block. The multiple traction blocks are placed on the slide plate and are rotatably connected to the slide plate through the rollers. In this way, the pulling of multiple plates and frames can be achieved through the pulling of multiple plate pulling mechanisms, which solves the current problem that only one plate and frame can be pulled at the same time, shortens the time of plate pulling, and improves the filtration efficiency of the filter press device .

Description of drawings

Fig. 1 is the schematic diagram of sewage sludge treatment device of the present invention;

Fig. 2 is the structural representation of drawing plate mechanism;

As shown in the figure, 1. Filter press device, 1.1, plate frame, 1.2, traction block, 1.3, slide plate, 1.4, hinged connecting rod, 1.5, roller, 2, crushing device, 3, drying device, 3.1, drying box, 3.2. Sludge turning mechanism, 4. Sludge freezing container, 5. Compressor, 6. First evaporator, 7. Condenser, 8. Second evaporator, 9. Throttle element, 10. Gas pipeline, 11. Working medium reversing valve, 12. Filtration structure, 13. Liquid reversing valve, 14. Liquid pipeline, 15. Rotor pump.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in the figure, a sewage sludge treatment device of the present invention includes a filter press device 1, a crushing device 2 and a drying device 3. The filter press device 1 carries out pressure filtration treatment on the sludge and is crushed by the crushing device 2. After the sludge is crushed, it enters the drying device 3 for drying treatment;

The sewage sludge treatment device also includes a sludge freezing container 4 and a freeze-drying energy circulation system, and the freeze-drying energy circulation system includes a compressor 5, a first evaporator 6, a condenser 7 and a sludge freezer. The second evaporator 8 in the container 4, the gas outlet end of the compressor 5 is connected with the condenser 6, the condenser 7 is connected with the first evaporator 6 through the throttling element 9, and the first evaporator 6 is connected with the second evaporator 8 The inlet end of the compressor 5 is connected; the condenser 7 communicates with the bottom of the drying device 3 through the gas pipeline 10, and the first evaporator 6 communicates with the top of the drying device 3 through the gas pipeline 10, while the condensing The device 7 communicates with the first evaporator 6 through a gas pipeline 10 .

The above technologies constitute the basic solution to solve the technical problems of the present invention.

There are multiple sludge freezing containers 4, and the second evaporator 8 corresponds to the sludge freezing container 4 one by one. The valve 11 is connected with the first evaporator 6 and the compressor 5, the bottom of the sludge freezing container 4 is provided with a filter structure 12, and the bottoms of a plurality of sludge freezing containers 4 pass through the liquid reversing valve 13 and through the liquid pipeline 14 and press filter The device 1 is connected; the thawed sludge is pumped into the filter press device 1 from the sludge freezing container 4 through the rotor pump 15 .

The drying device 3 includes a drying box 3.1 and a sludge turning mechanism 3.2. The sludge turning mechanism is arranged horizontally at different vertical heights in the drying box 3.1. The sludge turning mechanism The 3.2 structures are arranged in a staggered manner, and a sludge turnover mechanism 3.2 at the bottom layer extends out of the drying box 3.1.

The filter press device 1 is a plate and frame filter press, and the plate and frame filter press includes a plurality of plate frames 1.1, and a plate pulling mechanism is provided below the plate frames 1.1, and the plate pulling mechanism includes a plurality of traction blocks 1.2 and Skateboard 1.3, hinged connecting rod 1.4 is provided between two adjacent traction blocks 1.2, and roller 1.5 is provided under each traction block 1.2, and the multiple traction blocks 1.2 are placed on the slide plate 1.3, and pass through the rollers 1.5 is slidably connected with slide plate 1.3.

The process flow of sludge advanced treatment method is as follows:

1) Repeated freezing at a freezing temperature of -10°C to -15°C and a freezing time of 72 hours;

2) Thaw at 20-50°C (normal temperature can be used for thawing), and the thawing time is about 6 hours;

3) Carry out mechanical dehydration in the plate-and-frame filter press. First, it is the filter press stage. The filter press pressure is 1.0-1.2Mpa, and the filter press time is 1.5-2 hours. Entering the stage of pressing and dehydration, the pressing pressure is 1.5Mpa, and the pressing time is 1 hour. At this time, the moisture content of the sludge is about 60%-65%;

4) The large cake-like sludge from the plate and frame filter press is crushed in the sludge mixing and crushing device to form small sludge particles, and the size of the sludge particles is generally about 20mm;

5) Transport the crushed sludge into the drying device for drying. The drying device is a multi-layer flap type, the drying time is 2 hours, the drying temperature is 50-60°C, and the moisture content of the sludge after drying is 10%- 30%, at this time the second evaporator provides cooling capacity to the sludge freezing container;

The above steps are only staged steps of sludge treatment. The sludge can also be incinerated after being dried, and the waste heat can be recovered, and the waste heat can be used for thawing the frozen sludge in the sludge freezing container.

The specific working principle is as follows:

The sludge enters the sludge freezing container. First, under the action of the second evaporator, the refrigerant enters the second evaporator, and the working fluid absorbs heat on the sludge, so that the freezing temperature of the sludge reaches the specified temperature, and the sludge Repeated freezing at -10°C to -15°C and a freezing time of 72 hours destroys the binding force between sludge and water and the structure of the colloid, causing the colloid to destabilize and coagulate and the cell membrane to rupture. The sludge particles settle rapidly and the dehydration performance is greatly improved. Increase, the dehydration speed is dozens of times higher than before freezing, and the freezing is over. At this time, the working fluid reversing valve reverses the flow direction of the working fluid, and changes the flow direction of the working fluid to another sludge freezing container. At this time, air with a certain temperature is passed into the frozen sludge freezing container for thawing. The air temperature is between 20-50°C, and the thawing time is 6 hours.

After thawing, the sludge enters the rotor pump through the liquid pipeline. Under the pressure of the rotor pump, it enters the plate and frame machine (plate and frame filter press) to start pressure filtration for mechanical dehydration. After a period of pressure filtration, the plate and frame are pulled apart, The mud cake-like sludge falls into the material conveying device, and is transported to the crusher through the material conveying device. The crusher crushes the mud cake to form small sludge particles. The sludge increases the specific surface area of the sludge, which is beneficial to increase the contact area between the sludge and high-temperature air during drying, and improves the drying rate and effect.

Small sludge particles enter the upper flap in the dryer and fall from top to bottom layer by layer. During the falling process, the sludge will be turned over continuously, so that all surfaces are in full contact with the air. The dry air contacts the sludge from bottom to top. The air absorbs the moisture of the sludge and becomes moist air with high humidity. After passing through the first evaporator, it drops below the dew point and precipitates moisture. The precipitated moisture is discharged through the water storage pan, and the air After continuing to pass through the condenser, it is heated and enters the drying box to dry the sludge. After the sludge is heated and dried, it leaves the drying box after going through the bottom layer of flaps.

In order to better treat the sludge, after the above staged treatment, the sludge leaves the drying box and is transported to the incinerator through the material conveying device, and the primary air entering the combustion chamber is adjusted to make it in fluidized combustion under the action of the leveler. State, because the medium in the fluidized bed is in a suspended state, the gas and solid can be fully mixed and contacted, the temperature of the combustion section in the entire furnace is relatively uniform, and the exhaust gas generated after combustion is discharged into the waste heat boiler at about 850 °C. At the same time, the heat transfer oil in the waste heat boiler is heated from 220°C to 250°C. The heated heat transfer oil heats the air through the second heat exchanger, and the heated air enters the drying system and the thawing device to treat the sludge. Dry and thaw with heat. The gas purification device consists of two parts: acid gas removal and particle capture. Gas purification can be done by semi-dry method, spraying a certain amount of calcium oxide into the flue gas to make it react with the acidic substances in the flue gas, and pass through The spray device controls the moisture to reach the reaction process of spray drying. The deacidification reactant is basically a dry solid, and there will be no waste water discharge. The capture of particulate matter in the flue gas can be achieved through a filter combined with a cyclone separator or a cloth bag. A certain amount of activated carbon powder is sprayed before to absorb harmful substances such as heavy metals and dioxins in the flue gas. The purified gas can be discharged into the atmosphere with less pollution to the environment.

The above is only an illustration of the preferred embodiments of the present invention, but should not be construed as a limitation on the claims. The present invention is not limited to the above embodiments, and its specific structure is allowed to vary. In a word, all kinds of changes made within the protection scope of the independent claims of the present invention are within the protection scope of the present invention.

Claims (4)

1. A sewage sludge treatment device, comprising a filter press device (1), a crushing device (2) and a drying device (3), the filter press device (1) carries out pressure filtration treatment of sludge by the crushing device (2) Carry out crushing treatment, enter drying device (3) after sludge crushing and carry out drying treatment; It is characterized in that: The sewage sludge treatment device also includes a sludge freezing container (4) and a freeze-drying energy circulation system, and the freeze-drying energy circulation system includes a compressor (5), a first evaporator (6), a condenser ( 7) and the second evaporator (8) arranged in the sludge freezing container (4), the outlet end of the compressor (5) is connected to the condenser (7), and the condenser (7) passes through the throttling element (9) Connected with the first evaporator (6), the first evaporator (6) is connected with the intake end of the compressor (5) through the second evaporator (8); the condenser (7) passes through the gas pipeline (10 ) is communicated with the bottom of the drying device (3), the first evaporator (6) is communicated with the top of the drying device (3) through the gas pipeline (10), and the condenser (7) is connected with the drying device (3) through the gas pipeline (10) simultaneously. The first evaporator (6) is connected. 2. The sewage sludge treatment device according to claim 1, characterized in that: there are multiple sludge freezing containers (4), and the second evaporator (8) and the sludge freezing container (4) are one by one Correspondingly, the two ends of the second evaporator (8) in the plurality of sludge freezing containers (4) are respectively connected with the first evaporator (6) and the compressor (5) through the working fluid reversing valve (11), and the sludge The bottom of the sludge freezing container (4) is provided with a filter structure (12), and the bottoms of multiple sludge freezing containers (4) are connected to the filter press device (1) through the liquid reversing valve (13) and through the liquid pipeline (14). , the thawed sludge is pumped into the filter press device (1) from the sludge freezing container (4) through the rotor pump (15). 3. The sewage sludge treatment device according to claim 1 or 2, characterized in that: the drying device (3) comprises a drying box (3.1) and a sludge turnover mechanism (3.2), and the sludge The turnover mechanisms are horizontally arranged at different vertical heights in the drying box (3.1), the sludge turnover mechanisms (3.2) are arranged in a staggered manner, and a sludge turnover mechanism (3.2) at the bottom layer extends out of the drying box (3.1). 4. The sewage sludge treatment device according to claim 1 or 2, characterized in that: the filter press device (1) is a plate and frame filter press, and the plate and frame filter press includes a plurality of plate frames (1.1) , a plate pulling mechanism is provided below the plate frame (1.1), and the plate pulling mechanism includes a plurality of traction blocks (1.2) and slide plates (1.3), and a hinged link is arranged between two adjacent traction blocks (1.2) (1.4), and rollers (1.5) are provided under each traction block (1.2), and the multiple traction blocks (1.2) are placed on the slide plate (1.3), and pass through the rollers (1.5) and the slide plate (1.3) ) for scrollable connections.