CN209974591U - A multi-layer combined self-falling sludge drying device - Google Patents

Abstract

The utility model discloses a multilayer combination gravity type sludge drying device, including sludge drying machine, pre-heater, steam generator, filter, steam or separation of water buffer tank, vapor compressor, compressor cooling water pump, sealed discharging device, pipeline and valve etc.. The sludge dryer is mainly formed by combining a plurality of indirect dryer modules, the running mode of the sludge in the dryer is in a self-falling state, and the energy consumption required by mechanical operation can be greatly reduced. The inner cavity of the indirect dryer is high-temperature steam, and sludge is indirectly heated and dried; recovering condensed water generated in the cavity, introducing the recovered condensed water into a preheater, and preheating and impurity removing wet sludge; the secondary steam generated in the dryer becomes a new heat source for indirect heating in the cavity and bottom convection drying after being filtered, compressed and superheated. The device has reduced mechanical operation energy consumption and has avoided gluing the wall phenomenon, and the whole latent heat and the sensible heat of secondary steam are showing to the simultaneous recycle drying process, energy-conserving effect.

Description

A multi-layer combined self-falling sludge drying device

technical field

The utility model relates to the technical field of sludge drying, in particular to a multi-layer combined self-falling sludge drying device.

Background technique

Reducing the water content in the sludge is an effective way to reduce the amount of sludge. The effective way to reduce the water content is to use thermal energy to evaporate the water in the sludge to achieve the purpose of rapid drying. In the process of sludge drying, drying equipment, energy consumption, drying rate and secondary product treatment are involved. In particular, the sludge needs to consume a lot of energy during the drying process. At the same time, the composition of the sludge is complex and the moisture content is high, which makes the drying process more complicated; the sludge will have a condensation stage in the early stage of drying, which will make the sludge more complicated. The moisture content of the sludge increases, which reduces the drying efficiency of the sludge.

The sludge contains organic substances and other sticky substances, which cause the sludge to be blocked during the transportation process, and it is easy to produce a sticking phenomenon. The sticking problem exists in the chemical, pharmaceutical, food processing and textile industries. During the drying process The problem of material sticking to the wall not only increases the heat transfer resistance during drying and reduces the drying efficiency, but also causes hidden dangers to the safety of drying equipment.

According to the literature: drying characteristics of sludge superheated steam thin layer and drying model construction [J], Chinese Journal of Agricultural Engineering, Zhang Xukun, Sun Ruichen, Wang Xuecheng, etc., 2014, 30(14): 258-266 pages, it can be seen that the initial stage of superheated steam drying There is a condensation characteristic which is negative for the drying process, as steam condensation increases the moisture content of the material, extending the time of the overall drying process. Research on the drying shrinkage characteristics of superheated steam and hot air of sludge [D], Nanchang Aviation University, Wen Xiangdong, 2016, it can be seen that the decrease of water content in sludge will directly affect the volume of sludge, and the lower the moisture content, the smaller the sludge volume. Research on the stickiness in the drying process of urban sludge [D], Tianjin University, Liu Feng, 2008, it can be seen that in the initial stage of drying, the drying process occurs on the outer surface of the sludge. Entering the shrinkage stage, as the shrinkage progresses, the sludge surface tension decreases, the viscosity decreases, and cracks appear on the surface.

Application progress and technical points of sludge thermal drying process at home and abroad [J], China Water Supply and Drainage, Wang Xingrun, 2007, 23(8): 5-8, it can be seen that indirect heat conduction drying can recycle the drying medium, but in sewage The high moisture content stage of the mud is prone to sticky walls, resulting in large heat transfer resistance, high energy consumption and low drying efficiency. Research on indirect thin-layer drying of sludge and coupled dehydration and drying of thermal pressure [D], Dalian University of Technology, Wang Weiyun, 2012, through experiments, it was found that the closer the partition wall is to the heat transfer surface, the faster the sludge moisture content decreases. According to the experimental exploration of the influencing factors of sludge sticking and the analysis of the sticking mechanism [D], Tianjin University, Wu Zhaoqing 2007, it can be seen that when the sludge is indirectly dried, the main reason for the sticking is the water content of the sludge.

Teflon, also known as polytetrafluoroethylene (PTFE), has the comprehensive properties of high temperature resistance, corrosion resistance, non-stick, self-lubricating, and low friction coefficient. Coating Teflon on the drying device can effectively reduce sticking Phenomenon. When the sludge is in contact with the heating surface, the thin layer of the sludge in the contact part of the sludge and the heating surface is rapidly dried, the moisture content decreases, the contact part shrinks rapidly, and a steam film is formed between the heating surface and the sludge shrinking surface, It can also effectively prevent wall sticking and increase drying efficiency.

Steam has the advantages of good heat capacity, strong hygroscopic ability, and no mass transfer resistance, so that heat transfer materials such as rollers can be quickly heated.

At present, the devices and methods for energy-saving and drying sludge disposal are as follows:

Chinese patent CN 203741205 U discloses an indirect vertical multi-layer sludge dryer. The top of the mud inlet end of the vertical multi-layer dryer of the dryer is provided with an air outlet, and the bottom of the vertical multi-layer dryer is provided with an air outlet. It can further reduce the moisture content of sludge and form granular dry sludge, which is easy to utilize sludge resources, and has the characteristics of indirect heating, closed-circuit air circulation, and less waste steam.

Chinese patent CN 200989712 discloses a vertical sludge dryer, the drying tower is designed to be vertical, the sludge enters the tower from the top of the drying tower and falls freely, which saves the power required for transportation, and the hot air is transmitted from bottom to top. The sludge is transported from top to bottom, and the two form a cross flow. The sludge in the drying tower is evenly mixed with the hot air. Under the action of heat, the drying time is greatly shortened, and the water content of the sludge is reduced from 60% to below 30%, so the sludge becomes non-viscous hard lumps after drying. .

Chinese patent CN 102260033 A discloses a multi-stage drying method for secondary steam compression of sludge. In the method, the secondary steam generated by sludge drying is introduced into a steam/water separation buffer tank and then into a steam compressor, so that the steam It is reused as a heat source for the next stage of drying. However, this drying method needs to deal with a large amount of tail steam. When the steam and water are separated, the hot water to be separated brings out a lot of energy, and still a lot of steam will be mixed in the steam, which is very harmful to the compressor. While causing damage, the drying effect is reduced.

Chinese patent CN 1686876 A discloses a method for drying superheated steam of sludge and its drying device. The method recovers the latent heat and sensible heat of the drying tail steam through a heat exchanger, exchanges heat with water, and then heats the hot water It becomes superheated steam. Although this method recovers the latent heat in the drying of superheated steam, the heat exchange efficiency of the heat exchanger is not high, and when it is heated again to become steam, the energy consumption in the middle is very large, and only part of the energy saving effect can be achieved.

Chinese patent CN 205222968 U discloses an energy-saving sludge drying device utilizing waste heat. The heat collecting coil of the device is provided with a spiral groove concave into the inner body of the tube to ensure the contact area and improve the heat exchange efficiency. The water is heated by solar energy, and heat energy is generated by heating in the sunbathing pool. The waste heat recovery system recovers the heat energy, reduces the consumption of conventional energy, and is pollution-free.

Chinese patent CN 206828352 U discloses a waste water sludge treatment and recovery device, which reduces the viscosity of the sludge by heating the sludge during the sludge transmission process, not only reducing the sludge adhesion on the conveying device It is also conducive to the extraction of sludge, which solves the problem of inconvenient sludge transportation.

Chinese patent CN 107148814 A discloses a coupled bionic drag-reducing and viscosity-reducing plowshare, comprising a plowshare body and a bionic claw toe, the surface of the plowshare is coated with a layer of polytetrafluoroethylene coating, and the bionic claw toe monomer cross-sectional contour is composed of It is composed of three curves, which can effectively reduce the resistance of the soil-contacting parts, so that the adhesion of the sticky and wet soil is greatly reduced.

Chinese patent CN 207159076 U discloses a shock absorption stirring type chemical sludge drying device. The motor drives the second transmission wheel on the transmission shaft to rotate, the first transmission wheel is driven to rotate through the transmission belt, and the stirring shaft is driven to rotate to drive the semicircular stirring blades to rotate. The sludge in the arc-shaped position in the sludge drying tank is stirred, and the straight stirring blade is driven to stir the sludge in the central position of the sludge drying tank, and the scraper plate is driven to rotate to scrape the sludge on the inner wall of the sludge drying tank.

Chinese patent CN204079744 U discloses a double-shaft hollow paddle dryer, which adopts the reverse rotation method of two hollow shafts and paddles, and a scraper is arranged on the paddles to dry the sludge in the dryer The reverse rotation of the paddle will cut the sludge, reduce the sticking of the sludge, and enhance the drying efficiency of the sludge, so that the sludge does not need to be back mixed to prevent the sludge from sticking to the shaft and agglomerating. and other adverse phenomena.

Chinese patent CN205808034 U discloses a wedge-shaped hollow blade designed to mesh with each other and installed on two adjacent shafts. Steam is introduced into the shafts to conduct heat conduction and drying of the sludge. When the sludge adheres to the equipment At the same time, through the meshing effect between the blades, the effect of mutual cleaning is achieved, thereby reducing the adverse effect of sludge adhesion on drying and enhancing the heat transfer effect.

Chinese patent CN106219936 A discloses that by changing the structure of the paddle, the paddle can move back and forth in translation and vibrate in the fixed area on the shaft, so as to achieve the purpose of removing sludge from sticking on the shaft and the blade.

Chinese patent CN 206359409 U discloses an anti-adhesion sludge dryer. By arranging a plurality of parallel hollow shafts alternately provided with hollow discs in the cylinder of the dryer, and a mud scraper is arranged at one end of the hollow discs, the By adjusting the inclination angle of the hollow disc, the scraping and stripping effect of the sludge is realized, the sludge adhesion is reduced, and the sludge drying efficiency is improved.

Utility model content

The purpose of this utility model is to provide a multi-layer combined self-falling sludge drying device, so as to solve the problems of high energy consumption, complicated equipment, difficult maintenance, sticking to the wall and slow drying rate in the sludge drying process in the prior art. .

In order to achieve the above purpose, the utility model provides the following scheme: the utility model provides a multi-layer combined self-falling sludge drying device, including a preheater, a sludge dryer, a steam recovery mechanism and a steam generator. The bottom end of the preheater is communicated with the sludge feed port of the sludge dryer through the sludge conveying device. The sludge dryer includes a drying chamber and a multi-layer indirect dryer arranged in the drying chamber. The indirect dryer comprises a set of paired rollers, the roller surfaces of the pair of rollers are provided with annular grooves, and the rollers are provided with joints connected to the steam pipeline and the condensed water pipeline in the axial direction of the rollers. The bottom end of the chamber is provided with a sludge outlet and a convection steam inlet; the top of the drying chamber is also provided with a secondary steam outlet, which is communicated with the steam recovery mechanism through a pipeline, and the steam The heater in the recovery mechanism and the air outlet of the steam generator are confluent and communicate with the drying chamber.

Further, the preheater includes a sludge silo and a drying module, the sludge silo is arranged on the top of the drying module, the drying module includes a pair of rollers, and the axial direction of the pair of rollers is provided with The joint connected to the condensed water pipeline; the bottom of the drying module is connected with the sludge conveying equipment.

Further, the annular grooves are evenly distributed on the cylinder surface of the roller, the width of the grooves is greater than the distance between the two grooves, and the wall surfaces of the annular grooves are provided with demolding corners and rounded corners.

Further, the set number of layers of the indirect dryer is 5 layers vertically arranged from top to bottom, and the surfaces of the rollers of the indirect dryer on the third and fourth layers are sprayed with anti-adhesion materials. The adhesive material is Teflon material.

Further, the sludge discharge port is connected with a two-stage sealed discharge structure, and the sealed discharge structure includes a rotary valve.

Further, the steam recovery mechanism includes a filter, a first steam or water separation buffer tank, a steam compressor, a second steam or water separation buffer tank, and a heater, which are connected in sequence.

Further, the first steam or water separation buffer tank is provided with a pipeline connected with the condensed water pipeline and a cooling pipeline connected with the steam compressor, and a compressor cooling water pump is arranged on the cooling pipeline.

Further, the air outlets of the heater and the steam generator are connected to the sub-cylinder after confluence, and the air outlets of the sub-cylinder are respectively connected to the steam pipeline and the convective steam inlet; the condensate water pipeline is provided with a trap valve. .

The drying method applied to the above-mentioned multi-layer combined self-falling sludge drying device comprises the following steps:

(1) The wet sludge first passes through the preheater and then enters the sludge conveying equipment;

(2) The preheated sludge enters the sludge dryer from the sludge feed port and is dried by a multi-layer indirect dryer with steam;

(3) The secondary steam in the secondary steam outlet at the top of the dryer passes through the filter, the steam or water separation buffer tank 1, the steam compressor, the steam or separation buffer tank 2 and the heater in turn, and the recovered secondary steam It is combined with the steam in the steam generator, and part of the cylinder is passed through the inlet of the steam pipeline of each layer of indirect dryer to the inner cavity of the indirect dryer to release condensation heat for indirect heat conduction drying, and the other part passes through the convection steam inlet from the dryer. Bottom to top, convective drying of each layer of sludge;

(4) The dried sludge is discharged from the sludge discharge port of the sludge dryer through a two-stage sealed discharge structure.

The utility model has achieved the following technical effects with respect to the prior art:

1. The moving direction of sludge in the dryer is the same as the direction of gravity, and the dryer only needs a small amount of mechanical energy to rotate slowly;

2. The sludge passes through the preheater before entering the sludge drying unit to carry out impurity removal and preheating treatment, which can protect the device and increase the fluidity of the sludge, which can prevent the sludge from being trapped in the sludge pump. Blocking and reducing sludge condensation in the primary stage of sludge drying unit drying, speeding up drying efficiency;

3. Superheated steam is a drying medium, without mass transfer resistance, and the sludge surface is not easy to form crusts, which is conducive to further evaporation of water;

4. The inner cavity of the counter roller of the indirect dryer is high temperature steam, so that the sludge is rapidly dried and shrunk and a steam diaphragm is formed between the surface of the cylinder, and under the action of gravity and the rotation of the counter roller, it falls off and enters the next layer of indirect drying. device;

5. Part of the condensed water produced by the steam/water separation buffer tank is used for the cooling of the steam compressor. On the one hand, it solves the problem of the high exhaust temperature of the steam compressor, and on the other hand, it can prevent the failure of the main water injection pipeline of the steam compressor. Effectively avoid the compressor water cut off and dry burning;

6. The condensed water produced in the indirect dryer and the condensed water produced by the steam/water separation buffer tank are directly used for the preheating treatment of the sludge raw material in the sludge silo, and part of the sensible heat is recovered;

7. Use filter and steam/water separation buffer tank to purify the secondary steam, which not only purifies the exhausted steam but also protects the compressor;

8 When the sludge reaches the indirect dryer on the third and fourth layers, the viscosity of the sludge in the middle of drying reaches the maximum. After passing through the indirect dryer with Teflon material sprayed on the surface, the thin layer of sludge will be reduced in a short time. After being heated, the steam film formed between the Teflon coating and the Teflon coating loses a lot of water, which can smoothly pass through the drying sticking zone to solve the sticking phenomenon in the sludge drying process;

9. The heating interface composed of Teflon coating has low surface friction coefficient, low surface energy, self-lubrication, high temperature resistance, corrosion resistance and good heat transfer ability, which reduces the heat loss when the steam heat source transfers heat to the sludge;

10. Due to the low surface energy characteristics of the Teflon coating and the low moisture content of the sludge near the heating surface, the sticky substance in the sludge cannot completely wet the heating surface through the moisture in the sludge, which further reduces the sludge Sticky wall effect with heating surface;

11. After the secondary steam is recovered, it is used as a new heat source for indirect drying and convection drying, and all latent heat and sensible heat in the secondary steam are recovered;

12. The sludge dryer is of modular design, which is convenient for production and maintenance;

13. The non-condensable gas in the secondary steam is disposed of in the filter;

14. The sludge is extruded into strips, which is convenient for the transportation and treatment of sludge.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only of the present invention. For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

1 is a schematic structural diagram of the multi-layer combined self-falling sludge drying device of the present invention;

Fig. 2 is a schematic diagram of a sludge dryer;

Figure 3 is a three-dimensional graphic of a combination of 5-stage indirect dryer modules;

Fig. 4a is a schematic diagram of the shrinkage phenomenon of the sludge before being heated, and Fig. 4b is a schematic diagram of the shrinkage phenomenon of the sludge after being heated;

Figure 5 is a partial enlarged view of the sludge rapid heating stage on the heating surface of the indirect dryer;

Among them, 1 sludge dryer; 1-1 sludge inlet; 1-2 secondary steam outlet; 1-3 steam pipeline inlet; 1-4 convection steam inlet; 1-5 sludge outlet; 1- 6 Condensate pipe inlet; 1-7 Condensate pipe outlet; 2 Preheater; 3 Sludge injection pump; 4 Filter; 5 Steam or water separation buffer tank 1; 6 Steam compressor; 7 Steam or water separation buffer tank 2; 8 compressor cooling water pump; 9 heater; 10 steam generator; 11 sub-cylinder; 12 sealed discharge structure; 13 steam trap; a, b, c, d are all valves; A indirect dryer; B spray with Teflon coated indirect dryer; B-1 heater cylinder; B-2 Teflon coating; B-3 steam film; B-4 sludge close to the heating surface; B-5 sludge; C is The surface of the cylinder of the indirect heater; the pipes between 1-6 and 1-7 are condensate pipes.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the implementations. example. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

The purpose of this utility model is to provide a multi-layer combined self-falling sludge drying device, so as to solve the problems of high energy consumption, complicated equipment, difficult maintenance, sticking to the wall and slow drying rate in the sludge drying process in the prior art. .

In order to make the above objects, features and advantages of the present utility model more clearly understood, the present utility model will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Please refer to Figures 1-5, wherein Figure 1 is a schematic diagram of the structure of the multi-layer combined self-falling sludge drying device of the present invention; Figure 2 is a schematic diagram of a sludge dryer; Figure 3 is a three-dimensional figure of a 5-stage indirect dryer module combination; Figure 4a is a schematic diagram of the shrinkage phenomenon of the sludge before being heated, and 4b is a schematic diagram of the sludge shrinkage phenomenon after being heated; Figure 5 is a partial enlarged view of the rapid heating stage of the sludge on the heating surface of the indirect dryer.

As shown in Figures 1-5, the utility model provides a multi-layer combined self-falling sludge drying device, as shown in Figure 2 is a schematic diagram of the sludge dryer, the device adopts a modular design, as shown in the figure 5 Figure 3 shows the three-dimensional pattern of the combination of 5-stage indirect dryer modules, in which the surfaces of the third and fourth-stage module heater cylinders are sprayed with anti-adhesion materials. After the indirect dryer module unit is combined, as shown in Figure 3, it is placed in a closed box, and the top of the dryer is provided with a sludge feed port 1-1 connected to the sludge injection pump 3, and a secondary steam outlet 1- 2. Connect the filter 4, the steam or water separation buffer tank 1 5, the steam compressor 6, the steam or water separation buffer tank 2 7 and the heater 9 in turn. The bottom of the dryer is provided with sludge discharge ports 1-5 connected to the two-stage sealed discharge structure 12, and convection steam inlets 1-4 connected to the steam outlet of the sub-cylinder 11. The axial direction of the indirect dryer A of each stage is provided with a rotary joint to connect the steam pipe inlet 1-3 and the condensate pipe inlet 1-6, and further the steam pipe inlet 1-3 is connected to the steam outlet of the sub-cylinder 11.

The exhaust port of the steam generator 10 and the exhaust port of the heater 9 are connected to the steam inlet of the sub-cylinder 11 after mixing.

Below the preheater 2 is a modular unit of a large indirect dryer, which is axially provided with a rotary joint connected to the condensate pipe, and the joint is connected to the condensate pipe outlets 1-7. Further, between the condensate water pipe inlet 1-6 and the condensate water pipe outlet 1-7 is a condensate water pipe, and a trap valve 13 is arranged on the condensate water pipe.

The condensed water outlet produced by the steam/water separation buffer tanks 1 and 2 is connected to the condensed water pipeline, wherein the condensed water outlet of the steam or water separation buffer tank 1 5 is connected to the compressor cooling pump 8 and then to the cooling water nozzle pipeline of the steam compressor 6 connected.

This embodiment also provides a multi-layer combined self-falling sludge drying method, which utilizes the above-mentioned multi-layer combined self-falling sludge drying device for drying, which specifically includes the following steps:

After the sludge enters from the sludge feed port 1-1, it moves downward under the action of gravity and the rotation of the roller; a part of the steam in the sub-cylinder enters the inner cavity of the indirect dryer from the steam pipe inlet 1-3 Indirect heating drying is performed, and at the same time a part of the steam is convectively dried from the bottom to the top of the dryer from the bottom of the dryer from the convective steam inlets 1-4. In the dryer 1, due to the rapid heat transfer of the indirect dryer A, the thin layer of the sludge is rapidly dried and the volume shrinks, and a steam diaphragm is formed between the sludge and the cylinder surface C. As shown in Figure 4, the sludge is indirectly dried. Volume changes before and after heating.

In the early stage, the sludge is in the constant speed drying stage, the moisture content is high, and the sludge viscosity is not large. In the middle stage, the sludge viscosity reaches the maximum. At this time, the indirect dryer B is sprayed with Teflon coating.

As shown in Figure 5, it is a partial enlarged view of the sludge rapid heating stage of the heating surface of the indirect dryer. The outer surface of the heater cylinder B-1 is coated with a low surface energy Teflon coating B-2. Through this process While ensuring the heat transfer efficiency, the surface energy of the heating surface is reduced, and the wall sticking effect between the sludge and the sludge heating surface is reduced.

In the indirect drying stage of sludge viscosity reduction in the middle stage of drying, the normal temperature sludge enters the sludge indirect heating stage when it contacts the indirect heating surface. As shown in Figure 4, the surface drying rate of sludge B-4 close to the heating surface is higher than that of sludge B- 5 Much faster, the volume of sludge B-4 close to the heating surface shrinks sharply after the moisture content decreases sharply, and steam is formed between the sludge B-4 close to the heating surface and the low surface energy Teflon coating B-2 The film B-3 makes the sludge B-5 separate from the heating surface for a short time, which is beneficial to the separation of the sludge and the heating surface. Due to the sharp decrease in the moisture content of the sludge near the heating surface and the low surface energy characteristics of the heating surface, the sticky substances in the sludge B-5 cannot be in good contact with the heating surface and cannot form a stick-wall effect, so the pollution will be greatly reduced. Stick-to-wall effect of mud and heating surfaces.

At the same time, the condensed water generated in the indirect dryer cavity is discharged from the condensed water pipeline inlets 1-6 through the trap valve 13 and passed into the preheater 2 to preheat and remove impurities from the wet sludge from the sludge silo. It can increase the fluidity of the sludge, prevent the sludge from entering the sludge injection pump 3 and cause blockage and condensation in the initial drying stage in the dryer 1, and improve the drying efficiency; at the same time, the preheater 2 can also play a role in removing impurities. and protection of equipment.

The secondary steam generated in the sludge dryer 1 is discharged from the secondary steam outlet 1-2 to the filter 4 to remove impurities such as dust in the steam, and then passed into the steam or water separation buffer tank to remove the steam in the steam. water droplets; then increase the enthalpy value and temperature of the secondary steam through the steam compressor 6, and then pass into the steam or water separation buffer tank 2 to remove the compressed water droplets; and then pass through the heater 9 after proper overheating and the steam generator. 10 The supplemented primary steam is mixed and used as a new heat source. After passing through the sub-cylinder 11, a part enters the dryer cavity from the indirect steam pipe inlet 1-3, and a part enters the convective steam inlet 1-4.

The secondary steam passing through the filter 4 and the steam or water separator buffer tank 1 6 can remove dust and water droplets, protect the steam compressor 6 and prolong the service life of the compressor. At the same time, when the steam compressor 6 works for a long time, the exhaust temperature will be too high. Therefore, part of the condensed water in the steam or water separation buffer tank 1 6 passes through the compressor cooling water pump 8 to perform protective water spray cooling on the steam compressor 6. Another part of the condensed water is used for the preheating of the raw material of the preheater 2 .

After the indirect drying of the multi-layer indirect dryer A and the convective drying of the convective steam in the dryer 1, the sludge is discharged from the sludge discharge ports 1-5 through the two-stage sealed discharge structure 12.

The sludge dryer is mainly composed of several indirect dryer modules. Compared with paddle drying and disc drying equipment, the operation mode of the sludge in the dryer is in a self-falling state, and its gravity direction is the same as that of the sludge. The movement direction is the same, which can greatly reduce the energy consumption required for mechanical operation. The inner cavity of the indirect dryer is high-temperature steam, which indirectly heats and dries the sludge. Rapid heating reduces the moisture content of the sludge, reduces the volume, and shrinks the sludge toward the center. The condensed water generated in the cavity is recovered and passed into the preheater 2 to preheat and remove impurities from the wet sludge; the secondary steam generated in the dryer is filtered, compressed and superheated to become A new heat source for indirect heating in the cavity and bottom convection drying; low surface energy Teflon coating is sprayed on the heating contact surfaces of the third and fourth layers of indirect dryers, which can make the sludge appear viscous in the middle of drying. , It can pass through the indirect dryer smoothly, avoiding the phenomenon of sticking to the wall. The device can adopt a modular design method, which is not only easy to install and manufacture, but also reduces the energy consumption of mechanical operation and avoids the phenomenon of sticking to the wall.

The principles and implementations of the present utility model are described with specific examples in the present utility model, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present utility model; meanwhile, for those skilled in the art , according to the idea of the present utility model, there will be changes in the specific implementation and application scope. In conclusion, the content of this specification should not be construed as a limitation on the present invention.

Claims (8)

1. The utility model provides a multilayer combination gravity type sludge drying device which characterized in that: the sludge drying device comprises a preheater, a sludge drying machine, a steam recovery mechanism and a steam generator, wherein the bottom end of the preheater is communicated with a sludge feeding hole of the sludge drying machine through sludge conveying equipment, the sludge drying machine comprises a drying chamber and a multi-layer indirect dryer arranged in the drying chamber, the indirect dryer comprises a group of rollers, annular grooves are formed in the surfaces of rollers of the rollers, joints connected with a steam pipeline and a condensed water pipeline are arranged on the rollers in the axial direction of the rollers, and a sludge discharging hole and a convection steam inlet are formed in the bottom end of the drying chamber; the top end of the drying chamber is also provided with a secondary steam outlet, the secondary steam outlet is communicated with the steam recovery mechanism through a pipeline, and a heater in the steam recovery mechanism is communicated with the drying chamber after being converged with a gas outlet of the steam generator.

2. The multi-layer combined gravity type sludge drying device according to claim 1, wherein: the preheater comprises a sludge bin and a drying module, the sludge bin is arranged at the top of the drying module, the drying module comprises a group of pair rollers, and joints connected with condensed water pipelines are axially arranged on the pair rollers; the bottom of the drying module is connected with the sludge conveying equipment.

3. The multi-layer combined gravity type sludge drying device according to claim 1, wherein: the annular grooves are uniformly distributed on the surface of the roller, the width of each groove is larger than the distance between every two grooves, and the wall surfaces of the annular grooves are provided with demoulding angles and round corners.

4. The multi-layer combined gravity type sludge drying device according to claim 1, wherein: the number of layers of the indirect dryer is 5, the indirect dryer is vertically arranged from top to bottom, the surfaces of the rollers of the indirect dryer on the third layer and the fourth layer are sprayed with anti-adhesion materials, and the anti-adhesion materials are Teflon materials.

5. The multi-layer combined gravity type sludge drying device according to claim 1, wherein: the sludge discharge port is connected with the two-stage sealing discharge structure, and the sealing discharge structure comprises a rotary valve.

6. The multi-layer combined gravity type sludge drying device according to claim 1, wherein: the steam recovery mechanism comprises a filter, a first steam or water separation buffer tank, a steam compressor, a second steam or water separation buffer tank and a heater which are sequentially connected.

7. The multi-layer combined gravity type sludge drying device according to claim 6, wherein: and a pipeline connected with the condensed water pipeline and a cooling pipeline connected with the vapor compressor are arranged on the first steam or water separation buffer tank, and a compressor cooling water pump is arranged on the cooling pipeline.

8. The multi-layer combined gravity type sludge drying device according to claim 1, wherein: the air outlets of the heater and the steam generator are converged and then connected with the air distribution cylinder, and the air outlet of the air distribution cylinder is respectively connected with the steam pipeline and the convection steam inlet; and a drain valve is arranged on the condensed water pipeline.

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