Municipal sludge drying method and sludge treatment system thereof

Abstract

The invention discloses a municipal sludge drying method and a sludge treatment system thereof, and relates to the technical field of sludge treatment.The municipal sludge drying method comprises the steps that sludge is conveyed into a sludge storage pool, a reagent is added to condition liquid in the sludge storage pool, the sludge is stirred, and flocculent sludge is formed after the sludge is layered and coagulated; conveying the flocculent sludge into a belt filter press so as to preliminarily dehydrate the sludge; conveying the sludge subjected to preliminary dehydration into a screw conveyor, introducing hot air into the screw conveyor, and adding a heat accumulator so as to perform preliminary drying on the sludge. The method can effectively improve the technical effect of sludge deep treatment on the premise of ensuring that the water content reaches the standard after sludge deep treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of sludge treatment, and more specifically, to a municipal sludge drying method. In addition, the present invention also relates to a sludge treatment system suitable for the municipal sludge drying method. Background Art

[0002] At present, after the sludge from the sewage treatment plant is initially treated (water content 80%), it is further treated and disposed. The mainstream disposal technologies in China include sanitary landfill of sludge, inorganic treatment of sludge or land utilization of sludge, sludge drying and incineration, etc. Among them, the technical principle of sanitary landfill of sludge is: transport the dehydrated sludge to the sanitary landfill together with the urban garbage and dispose of it according to the sanitary landfill operation. It has the disadvantages of large land occupation, heavy leachate and odor pollution, heavy environmental protection and secondary pollution. The technical principle of inorganic treatment of sludge or land utilization of sludge is: use sludge as raw material to manufacture various building materials. The final product of its treatment (pretreatment and building material manufacturing) is a material product that can be used in various types of construction projects. It has the disadvantages of complex treatment process, relatively long treatment cycle, high impurity removal requirements, and large investment. The technical principle of sludge drying and incineration is to use steam, flue gas or other heat sources to remove moisture from sludge, and the incineration process uses the calorific value of sludge to reduce the sludge and make it a resource. It has the disadvantages of large investment, high energy consumption, and the need to prevent secondary pollution of sludge water, gas and solid during the treatment process. It can be seen that the current mainstream sludge deep treatment and disposal processes have more or less shortcomings and deficiencies.

[0003] In summary, how to effectively improve the technical effect of sludge deep treatment while ensuring that the moisture content of the sludge after deep treatment meets the standard is a problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a municipal sludge drying method, which can effectively improve the technical effect of sludge deep treatment while ensuring that the moisture content of the sludge after deep treatment meets the standard.

[0005] Another object of the present invention is to provide a sludge treatment system suitable for the above-mentioned municipal sludge drying method.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A municipal sludge drying method, comprising:

[0008] Transporting the sludge to a sludge storage tank, adding reagents to condition the liquid in the sludge storage tank, stirring the sludge, and waiting for the sludge to be stratified and coagulated to form flocculent sludge;

[0009] Transport the flocculent sludge to a belt filter press for preliminary dewatering of the sludge;

[0010] Transport the preliminarily dewatered sludge to a screw conveyor. Meanwhile, introduce hot air into the screw conveyor and add a heat storage body to preliminarily dry the sludge.

[0011] In one embodiment, transporting the sludge to a sludge storage tank, adding a reagent to condition the liquid in the sludge storage tank, and stirring the sludge, and waiting for the sludge to stratify and coagulate to form flocculent sludge includes:

[0012] A pump set transports the sludge to the sludge storage tank, adds PAM to the liquid in the sludge storage tank, controls the agitator in the sludge storage tank to stir the sludge, stops stirring after stirring for a preset time, and waits for the sludge to stratify and coagulate.

[0013] In one embodiment, transporting the flocculent sludge to a belt filter press for preliminary dewatering of the sludge includes:

[0014] A pump set transports the flocculent sludge to the belt filter press for preliminary dewatering of the sludge, separates the water liquid and returns it to the sludge storage tank.

[0015] In one embodiment, introducing hot air into the screw conveyor and adding a heat storage body includes:

[0016] A steam generator introduces high-temperature steam into a heating reactor to heat the heat storage body, transports the heat storage body to the first feed port of the screw conveyor and enters the screw conveyor. Meanwhile, transports the hot air generated during the operation of the steam generator to the air inlet of the screw conveyor and enters the screw conveyor.

[0017] In one embodiment, after the preliminary drying of the sludge, the following includes: the sludge drops from the second discharge port of the screw conveyor, the heat storage body drops from the first discharge port of the screw conveyor, transports the separated heat storage body to the upper half of the heating reactor for heating, transports the separated sludge into the next process, or transports the separated sludge back to the step of transporting the preliminarily dewatered sludge to the screw conveyor. Meanwhile, introduce hot air into the screw conveyor and add a heat storage body to preliminarily dry the sludge.

[0018] In one embodiment, the steam generator introducing high-temperature steam into the heating reactor to heat the heat storage body includes:

[0019] The steam of the steam generator reaches the upper half of the heating reactor through a pipeline to heat the heat storage body in the upper half of the heating reactor. When the heat storage body reaches a preset temperature after being heated for a preset time, the electric ball valve below the upper half of the heating reactor is opened, and the heated heat storage body enters the lower half of the heating reactor through the electric ball valve. When all the heat storage bodies in the upper half have fallen to the lower half of the heating reactor, the conveying device conveys part of the heat storage bodies to be heated to the upper half of the heating reactor;

[0020] Open the electric ball valve in the lower half of the heating reactor, and the heated heat storage body enters the screening machine to screen heat storage bodies of different specifications into different collectors to obtain heat storage bodies with different mixing ratios;

[0021] When all the heat storage bodies in the lower half of the heating reactor have fallen and the heat storage bodies in the upper half of the heating reactor reach the preset temperature, return to the above two operation steps to continuously heat the heat storage bodies.

[0022] In one embodiment, the conveying of the separated sludge into the next process includes:

[0023] Conveying the separated sludge into the steam generator to be mixed and incinerated with flammable materials, and the residue of the sludge after incineration is conveyed to a brick factory to make bricks.

[0024] In one embodiment, after the sludge is preliminarily dried, it further includes: an induced draft fan draws the odor generated during the preliminary drying of the sludge to a biological filter, and the odor stays in the biological filter for at least 21 s to perform odor removal operation in the biological filter.

[0025] A sludge treatment system applicable to the municipal sludge drying method described in any one of the above, includes:

[0026] A sludge storage tank, which is provided with a mixer inside;

[0027] A pharmaceutical machine, which is used to prepare a reagent to condition the liquid in the sludge storage tank, and the medicine outlet end of the pharmaceutical machine is communicated with the medicine adding end of the sludge storage tank;

[0028] A belt filter press, which is used to perform preliminary dehydration on the sludge, and its feed inlet is communicated with the discharge outlet of the sludge storage tank;

[0029] A screw conveyor, which is used to preliminarily dry the sludge, and its feed inlet is communicated with the discharge outlet of the belt filter press;

[0030] A heat source device for heating a heat storage body and generating hot air, the discharge port thereof is communicated with the first feed port of the screw conveyor, and the air outlet of the heat source device is communicated with the air inlet of the screw conveyor.

[0031] In one embodiment, the heat source device includes a steam generator and a heating reactor. The steam generator is communicated with the upper half of the heating reactor through a steam pipeline. Electric ball valves are provided between the upper half and the lower half of the heating reactor and below the lower half of the heating reactor.

[0032] The lower half of the heating reactor is communicated with the inlet of a screening machine. The outlet of the screening machine is respectively communicated with a plurality of collectors. The discharge ports of the collectors are all connected to the input end of a conveying device, and the output end of the conveying device is communicated with the first feed port.

[0033] When using the municipal sludge drying method provided by the present invention, first, sludge (with a moisture content of about 80%) is transported to a sludge storage tank. Reagents are added to the sludge storage tank to adjust the liquid in the sludge storage tank, and a stirrer is used to stir the sludge and the reagents in the sludge storage tank. After stirring in place, wait for a period of time to make the sludge stratify and coagulate to form flocculent sludge.

[0034] Then, the flocculent sludge is transported into a belt filter press for preliminary dehydration of the sludge, separating the sludge and the aqueous liquid. The aqueous liquid can be refluxed to the sludge storage tank for re-conditioning to save water. The moisture content of the preliminarily dehydrated sludge is about 60%.

[0035] Finally, the preliminarily dehydrated sludge is transported to a screw conveyor. Since the screw conveyor is a closed cylindrical space, the sludge will be crushed during the process of the screw conveyor transporting the sludge. Moreover, when transporting the sludge by the screw conveyor, hot air is simultaneously introduced into the screw conveyor, and a heat storage body (the heat storage body is an item with a relatively large heat conduction capacity) is added. Both the heat storage body and the hot air exchange heat with the sludge to perform preliminary drying on the sludge, which helps to reduce the moisture content of the sludge to below 45%. The treatment process is relatively simple and the sludge treatment cycle is relatively short.

[0036] In addition, the sludge itself has calorific value. When the moisture content of the sludge is less than 55%, the calorific value of the sludge is about 1200 kcal / kg. The sludge can be mixed with other flammable materials and burned for value utilization of the sludge. Moreover, the residue after burning the sludge can be transported to a brick factory as brick-making materials to achieve the reduction and resource utilization of the sludge. And using this method to deeply treat the sludge can not only make the moisture content of the sludge meet the standard, but also the equipment required for the treatment process is simple and the investment is relatively small.

[0037] In summary, the municipal sludge drying method provided by the present invention can effectively improve the technical effect of sludge deep treatment on the premise of ensuring that the moisture content meets the standard after deep treatment of sludge.

[0038] In addition, the present invention also provides a sludge treatment system applicable to the above-mentioned municipal sludge drying method. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0040] Figure 1 It is a schematic flow chart of the municipal sludge drying method provided by the present invention;

[0041] Figure 2 It is a schematic structural diagram of a sludge storage tank;

[0042] Figure 3 It is a schematic structural diagram of a sludge storage tank, a pharmaceutical machine, and a belt filter press;

[0043] Figure 4 It is a schematic structural diagram of a screw conveyor;

[0044] Figure 5 It is a partially enlarged view of the screw conveyor;

[0045] Figure 6 It is a schematic structural diagram of a screening mesh;

[0046] Figure 7 It is a schematic structural diagram of an air outlet plate;

[0047] Figure 8 It is a schematic structural diagram of a heat source device;

[0048] Figure 9 It is a schematic structural diagram of a heating reactor.

[0049] Figures 1-9 Among them:

[0050] 1 is a sludge storage tank, 11 is a mixer, 12 is a mixing frame, 13 is a sump, 14 is a slide, 2 is a pharmaceutical machine, 21 is a preparation machine, 22 is a screw pump, 23 is a reagent barrel, 24 is a reagent pipeline, 25 is a reagent flowmeter, 3 is a belt filter press, 31 is a sludge inlet pipeline, 32 is a hydraulic piston pump, 33 is a reflux pipeline, 34 is a front pneumatic ball valve, 35 is a rear pneumatic ball valve, 36 is a reflux pneumatic ball valve, 4 is a screw conveyor, 41 is an upper air duct, 42 is an air outlet plate, 43 is a spiral structure, 44 is a screening plate, 45 is a lower air duct, 46 is a rake tooth, 47 is a first feed inlet, 48 is a second feed inlet, 49 is an air outlet, 410 is a first outlet, 411 is a second outlet, 412 is an air inlet, 413 is a motor, 5 is a heat source device, 51 is a steam generator, 52 is a heating reaction kettle, 521 is an inner chamber, 522 is an outer chamber, 523 is an exhaust port, 524 is a steam inlet, 525 is a steam outlet, 53 is an electric ball valve, 54 is a screening machine, 55 is a collector, 56 is a conveying device, 57 is a steam pipeline. Detailed implementation mode

[0051] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0052] The core of the present invention is to provide a municipal sludge drying method, which can effectively improve the technical effect of deep sludge treatment on the premise of ensuring that the moisture content of the sludge reaches the standard after deep treatment. Another core of the present invention is to provide a sludge treatment system applicable to the above-mentioned municipal sludge drying method.

[0053] This specific embodiment provides a municipal sludge drying method, as Figure 1 shown, including:

[0054] S1. Transport the sludge to the sludge storage tank 1, add reagents to condition the liquid in the sludge storage tank 1, and stir the sludge, and wait for the sludge to stratify and coagulate to form flocculent sludge;

[0055] S2. Transport the flocculent sludge to the belt filter press 3 to perform preliminary dehydration on the sludge;

[0056] S3. Transport the preliminarily dehydrated sludge to the screw conveyor 4. At the same time, introduce hot air (which is obtained by heating air after steam passes through a heat exchanger) into the screw conveyor 4, and add a heat storage body to perform preliminary drying on the sludge.

[0057] When using the municipal sludge drying method provided by the present invention, first, sludge (with a water content of about 80%) is transported to the sludge storage tank 1. Reagents are added to the sludge storage tank 1 to adjust the liquid in the sludge storage tank 1, and a mixer 11 is used to stir the sludge and reagents in the sludge storage tank 1. After stirring is in place, wait for a period of time to allow the sludge to stratify and agglomerate to form flocculent sludge.

[0058] Then, the flocculent sludge is transported into a belt filter press 3 for preliminary dehydration of the sludge, separating the sludge and the liquid. The liquid can be recycled to the sludge storage tank 1 for re-conditioning, saving water. The water content of the preliminarily dehydrated sludge is about 60% or so.

[0059] Finally, the preliminarily dehydrated sludge is transported to a screw conveyor 4. Since the screw conveyor 4 is a closed cylindrical space, the sludge will be crushed during the process of transporting the sludge by the screw conveyor 4. Moreover, when transporting the sludge by the screw conveyor, hot air is simultaneously introduced into the screw conveyor 4, and a heat storage body (the heat storage body is an item with a relatively large heat conduction capacity) is added. Both the heat storage body and the hot air exchange heat with the sludge for preliminary drying of the sludge, which helps to reduce the water content of the sludge to less than 45%. The treatment process is relatively simple and the sludge treatment cycle is relatively short.

[0060] In addition, the sludge itself has calorific value. When the water content of the sludge is less than 55%, the calorific value of the sludge is about 1200 kcal / kg. The sludge can be mixed with other flammable materials and burned for value utilization of the sludge. Moreover, the residue of the sludge after burning can be transported to a brick factory as brick-making materials to achieve the reduction and resource utilization of the sludge. And using this method for in-depth treatment of the sludge can not only make the water content of the sludge meet the standard, but also the equipment required for the treatment process is simple and the investment is relatively small.

[0061] In summary, the municipal sludge drying method provided by the present invention can effectively improve the technical effect of in-depth treatment of sludge on the premise of ensuring that the water content of the sludge meets the standard after in-depth treatment.

[0062] In one embodiment, transporting sludge to the sludge storage tank 1, adding reagents to condition the liquid in the sludge storage tank 1 and stirring the sludge, and waiting for the sludge to stratify and agglomerate to form flocculent sludge, includes:

[0063] A pump group (or other conveying device) transports sludge to the sludge storage tank 1, adds PAM (Polyacrylamide) to the sludge storage tank 1 to condition the liquid in the sludge storage tank 1, and controls the mixer 11 in the sludge storage tank 1 to stir the sludge. After the mixer 11 stirs the sludge for a preset time, control the mixer 11 to stop the stirring operation, and wait for a period of time to allow the sludge to stratify and agglomerate to form flocculent sludge.

[0064] In one embodiment, flocculent sludge is conveyed to a belt filter press 3 for preliminary dewatering of the sludge, including: a pump set conveys the flocculent sludge to the belt filter press 3 for preliminary dewatering of the sludge, and the separated water liquid is refluxed to the sludge storage tank 1.

[0065] It should be supplemented and explained that the preliminary dewatering of the sludge by the belt filter press 3 means that the flocculent sludge first enters the gravity dewatering zone of the belt filter press 3, and most of the free water in the flocculent sludge is filtered out through the filter belt under the action of gravity. As the filter belt runs, the sludge enters the wedge-shaped zone composed of multiple filter belts, and the multiple filter belts apply slow pressure to the sludge, causing the sludge to gradually thicken, reducing its fluidity, and transitioning to the pressing zone; in the pressing zone, the sludge is subjected to an increasing squeezing force and the shearing force generated by the alternating up and down positions of the multiple filter belts, and most of the free water and interstitial water remaining in the sludge are filtered out, and the sludge becomes a sheet-like filter cake with a lower water content; the upper and lower filter belts are separated by the discharge roller, and the filter cake is scraped off by means of the change in the curvature of the filter belt and using a scraper to achieve solid-liquid separation of the material, while the upper and lower filter belts are reused after being washed for the next cycle of concentration and filtration.

[0066] In one embodiment, hot air is introduced into the screw conveyor 4 and a heat storage body is added, including:

[0067] The steam generator 51 introduces high-temperature steam into the heating reaction kettle 52 to heat the heat storage body, conveys the heat storage body to the first feed port 47 of the screw conveyor 4 and enters the screw conveyor 4. At the same time, the hot air generated during the operation of the steam generator 51 is conveyed to the air inlet of the screw conveyor 4 and enters the screw conveyor 4. That is, because the screw conveyor 4 is a closed cylindrical space, during the transportation of the sludge, along with the crushing of the material sludge, when the sludge is conveyed by the screw, hot air is simultaneously introduced into the screw conveyor 4 and a heat storage body (which is an item with a large heat conduction capacity) is added, and both the heat storage body and the hot air exchange heat with the sludge to preliminarily dry the sludge and effectively reduce the water content of the sludge.

[0068] In one embodiment, after the sludge is preliminarily dried, it includes:

[0069] The sludge falls from the second discharge port 411 of the screw conveyor 4, and the heat storage body falls from the first discharge port 410 of the screw conveyor 4. The separated heat storage body is conveyed to the upper half of the heating reaction kettle 52 for heating, and the separated sludge is conveyed into the next process. If the dried sludge needs to be further deeply dried, a set of screw conveyor 4 can be added and the above process can be repeated to further dry the sludge (which is applicable to the case where the degree of sludge drying meets the standard), or the separated sludge is conveyed back to the screw conveyor 4 for conveying the sludge after preliminary dewatering. At the same time, hot air is introduced into the screw conveyor 4 and a heat storage body is added to perform the step of preliminarily drying the sludge (which is applicable to the case where the degree of sludge drying does not meet the standard).

[0070] In one embodiment, the steam generator 51 feeds high-temperature steam into the heating reactor 52 to heat the heat storage body, including:

[0071] The steam from the steam generator 51 reaches the upper half of the heating reactor 52 through a pipeline to heat the heat storage body in the upper half of the heating reactor 52. When the heat storage body reaches a preset temperature after heating for a preset time, the electric ball valve 53 below the upper half of the heating reactor 52 is opened, and the heated heat storage body enters the lower half of the heating reactor 52 through the electric ball valve 53. When all the heat storage bodies in the upper half have fallen to the lower half of the heating reactor 52, the conveying device 56 conveys some of the heat storage bodies to be heated to the upper half of the heating reactor 52;

[0072] The electric ball valve 53 in the lower half of the heating reactor 52 is opened, and the heated heat storage body enters the screening machine 54 to screen heat storage bodies of different specifications into different collectors 55 to obtain heat storage bodies with different mixing ratios;

[0073] When all the heat storage bodies in the lower half of the heating reactor 52 have fallen and the heat storage bodies in the upper half of the heating reactor 52 reach the preset temperature, the above two operation steps are repeated to continuously heat the heat storage body.

[0074] In one embodiment, the conveyed and separated sludge enters the next process, including:

[0075] The conveyed and separated sludge is transported into the steam generator 51 to be mixed and incinerated with flammable materials, and the residue of the sludge after incineration is transported to a brick factory to make bricks.

[0076] It should be noted that since the sludge (which can be municipal sludge) is an organic matter and has its own energy. According to research, when the moisture content of the sludge is 55%, the heat of the sludge is about 1200 kcal. Therefore, the preliminarily dried sludge can be transported to the steam generator 51 to be mixed and incinerated with flammable materials (such as charcoal), so as to make full use of the energy in the sludge. At the same time, steam is generated by the steam generator 51 for internal use in the plant, forming energy recovery and utilization, which can achieve the effect of energy conservation and environmental protection.

[0077] In one embodiment, after the sludge is preliminarily dried, it further includes: the induced draft fan draws the odor generated during the preliminary drying of the sludge to the biological filter, and the odor stays in the biological filter for at least 21 s to remove the odor in the biological filter.

[0078] It should be noted that the entire workshop is designed as a fully sealed structure. When deeply treating sludge, odors will be generated. Through a biological deodorization device, a slightly negative pressure state is formed in the workshop, and all odors enter the biological filter through an induced draft fan. The odors stay in the biological filter for at least 21 seconds, and the odors are deodorized in the biological filter to avoid adverse effects on the health of operators.

[0079] In addition to the above municipal sludge drying method, the present invention also provides a sludge treatment system applicable to the municipal sludge drying method of any one of the above. The sludge treatment system includes:

[0080] A sludge storage tank 1, which is provided with a mixer 11 inside, and the structure is as Figure 2 shown. A slide 14 can be arranged at the bottom of the sludge storage tank 1 to prevent sludge from accumulating at the bottom of the sludge storage tank 1. Moreover, the mixer 11 can be fixed on one side of the sludge storage tank 1 through a mixing frame 12, and a sump 13 is arranged at the bottom of the sludge storage tank 1 to facilitate the collection of sludge when cleaning the sludge. Among them, the mixing frame 12 is used to drive the sludge to stir and break the sludge, and the sump 13 is used to place the bottom valve and facilitate cleaning when cleaning the sludge tank later;

[0081] A pharmaceutical machine 2, which is used to prepare reagents to condition the liquid in the sludge storage tank 1. The medicine outlet end of the pharmaceutical machine 2 is communicated with the medicine adding end of the sludge storage tank 1, and the structure is as Figure 3 shown. The pharmaceutical machine 2 includes a preparation machine 21, a screw pump 22, and a reagent barrel 23 connected in sequence. The medicine outlet end of the reagent barrel 23 is communicated with the medicine adding end of the sludge storage tank 1 through a reagent pipeline 24, and a reagent flowmeter 25 is arranged on the reagent pipeline 24 to facilitate the control of the reagent dosage;

[0082] A belt filter press 3, which is used for preliminary dehydration of sludge. Its feed inlet is communicated with the discharge outlet of the sludge storage tank 1, and the structure is as Figure 3 shown. A sludge inlet pipeline 31 is arranged between the discharge outlet of the sludge storage tank 1 and the feed inlet of the belt filter press 3, and a hydraulic plunger pump 32 is arranged on the sludge inlet pipeline 31 to drive the sludge to flow. Moreover, the water outlet of the belt filter press 3 can be connected to the sludge storage tank 1 through a return pipeline 33, and a return pneumatic ball valve 36 is arranged on the return pipeline;

[0083] A screw conveyor 4, which is used for preliminary drying of sludge. Its feed inlet is communicated with the discharge outlet of the belt filter press 3, and the structure is as Figure 4 shown. The screw conveyor 4 includes two screw conveyors 4 distributed up and down to extend the crushing and drying process of the sludge;

[0084] A heat source device 5, which is used to heat the heat storage body and generate hot air. Its discharge outlet is communicated with the first feed inlet 47 of the screw conveyor 4, and the air outlet of the heat source device 5 is communicated with the air inlet 412 of the screw conveyor 4.

[0085] This system uses the heat source device 5 as the heat source. After processes such as heating the heat storage body, crushing the sludge, and passing hot air, the moisture in the sludge is evaporated, reducing the moisture content of the sludge to below 45%, forming a combustible sludge fuel. Then, the sludge fuel can be used as a supplement to the steam generator 51, ultimately forming a closed loop and effectively reducing energy consumption. Moreover, it reduces the secondary pollution of the sludge during transportation. At the current stage, during the sludge transportation process, the sludge has a high moisture content, and corresponding treatment measures need to be taken for both the transportation vehicles and the sludge odor. At this time, this method can also be adaptively used to reduce the moisture content of the sludge to reduce the large transportation costs during the sludge transportation process. And when the moisture content of the sludge is less than 55%, the approximate calorific value of the sludge is 1200 kcal / kg. The sludge can be mixed with other flammable materials and burned together for value utilization of the sludge. The residue after burning is transported to the brick factory and used as brick-making materials.

[0086] It should be noted that, to further illustrate the preparation process of the pharmaceutical machine 2, an example is given. First, the preparation machine 21 precisely prepares the PAM reagent according to the established process. This reagent has specific concentrations and properties. After preparation, it is stably and efficiently transported to the PAM storage tank through the screw pump 22. The screw pump 22 uses the pushing force generated by the rotation of the screw to ensure the stable transportation of the reagent and avoid affecting the quality of the reagent due to instability during transportation. The PAM storage tank plays a role in temporarily storing the reagent to ensure that the reagent can be supplied at any time when needed. When the production process requires the addition of the PAM reagent, the PLC control system opens the pneumatic ball valve 35 at the rear end of the PAM according to the preset program. At this time, the reagent realizes self-flow transportation under the action of its own gravity. The self-flow process not only saves additional power consumption but also ensures the continuity of the reagent transportation. When the reagent flows through the reagent flowmeter 25, the reagent flowmeter 25 uses advanced sensing technology to accurately measure the volume or mass of the passing reagent and accumulates the data in real time. At the same time, the reagent flowmeter 25 feeds back the accumulated data to the PLC control system in the form of an electrical signal. The PLC control system analyzes and processes the feedback data. Once the data reaches the preset dosing value, it immediately issues an instruction to automatically close the pneumatic ball valve 35 at the rear end, accurately stopping the reagent transportation, thereby ensuring the accuracy of the reagent dosing amount and avoiding adverse effects on the subsequent process caused by excessive or insufficient dosing.

[0087] Then, when the PAM agent is successfully delivered to the sludge storage tank 1, the agitator 11 is immediately started. The agitator 11 usually adopts an agitator with a specific blade shape and rotation speed, and its function is to fully mix the PAM agent with the sludge in the sludge storage tank 1. During the stirring process, the high molecular polymer in the PAM agent interacts with the sludge particles, and through mechanisms such as adsorption and bridging, it promotes the aggregation of sludge particles to form larger floc structures, achieving the flocculation effect. This process can significantly change the physical properties of the sludge and improve the subsequent treatment efficiency. When the flocculation effect reaches the expectation, the operation of the agitator 11 is stopped to avoid over-stirring and damaging the formed floc structure.

[0088] After that, when treating the sludge, first, the PLC control system issues an instruction to open the front pneumatic ball valve 34 at the front end. The front pneumatic ball valve 34 responds quickly and can quickly open the channel to allow the sludge to pass through smoothly. After the sludge passes through the opened front pneumatic ball valve 34, it enters the hydraulic piston pump 32. The hydraulic piston pump 32 selects a suitable model according to the characteristics of the sludge, such as viscosity and particle size. It has a powerful conveying capacity and can convey the sludge from the initial position to the belt filter press 3. During the operation of the hydraulic piston pump 32, the motor drives the impeller to rotate, generating a powerful suction force and thrust to ensure the stable conveyance of the sludge. The sludge is output from the rear end of the hydraulic piston pump 32 and is accurately conveyed to the belt filter press 3 along the sludge inlet pipe 31, preparing for the subsequent solid-liquid separation process.

[0089] Finally, after the belt filter press 3 is started, the incoming sludge is subjected to primary pressing. During the pressing process, the water in the sludge is squeezed out through the extrusion of the upper and lower filter belts and the coordinated action of a series of mechanical devices. After the primary pressing, sludge with a moisture content of about 60% and pressing water are produced. At this time, the sludge has been preliminarily separated into solid and liquid and has a certain shape and stability. The pressing water passes through the return pneumatic ball valve 34 on the return pipe 33 and returns to the sludge storage tank 1. The purpose of the return is to reuse the residual sludge and the incompletely reacted agent that may be contained in the pressing water, improve the resource utilization rate, reduce the treatment cost, and at the same time reduce the pollution risk to the external environment.

[0090] In addition, to further illustrate the structural role of the screw conveyor 4, etc., supplementary explanations are made. The screw conveyor 4 plays a crucial role in the sludge treatment process, and one of its main functions is to achieve efficient sludge conveyance. As Figures 4-7As shown, the screw conveyor 4 includes an upper air duct 41, an air outlet plate 42, a spiral structure 43, a screening plate 44, a spiral structure 43, an air outlet plate 42 and a lower air duct 45 which are arranged in sequence from top to bottom. The spiral structure 43 is driven by a motor 413, and rake teeth 46 are arranged on the spiral structure 43. In addition, a first feed port 47 for introducing a heat storage body and a second feed port 48 for introducing sludge are arranged at the top of the first end of the upper air duct 41, an air outlet 49 for connecting to an induced draft fan is arranged at the top of the second end of the upper air duct 41, a first outlet 410 for discharging the heat storage body is arranged at the bottom of the second end of the upper air duct 41, a second outlet 411 for discharging sludge is arranged at the bottom of the second end of the lower air duct 45, and an air inlet 412 for connecting to a hot air blower is arranged at the bottom of the first end of the lower air duct 45.

[0091] The spiral structure 43 of the screw conveyor 4 is designed to generate continuous and stable thrust during rotation, like an orderly propeller, to smoothly push the sludge along a specific conveying path. Compared with some other conveying methods, this conveying method has better adaptability and can effectively deal with the characteristics of high viscosity and poor fluidity of sludge, ensuring that the sludge can be smoothly transferred from one processing link to the next, greatly improving the efficiency and reliability of sludge conveying.

[0092] Secondly, the screw conveyor 4 also has the function of crushing sludge during the process of conveying sludge. Sludge usually appears in block or agglomerate form, which is not conducive to subsequent treatment procedures. During the rotation process, the spiral blades of the screw conveyor 4 will produce a strong mechanical effect on the sludge, and the larger pieces of sludge will be crushed through the scraping, squeezing of the spiral blades and the crushing of the rake teeth 46. This crushing action can refine the sludge particles, increase the specific surface area of ​​the sludge, create more favorable conditions for subsequent flocculation, dehydration and other treatment processes, enable the sludge to be more fully in contact with the treatment agent, and improve the treatment effect.

[0093] At the same time, a screening plate 44 is provided in the screw conveyor 4, wherein the aperture of the screening plate 44 is smaller than the diameter of the heat storage body, so that most of the sludge and the heat storage body are screened by the screening plate 44, and only a small part of the sludge flows back to the heat storage body heating device (i.e., the heating reactor 52) together with the heat storage body, so that the crushed sludge and the heat storage body can be separated, thereby achieving the purpose of reusing the heat storage body; at the same time, the hole spacing of the lower air duct and the upper air duct is opened according to the spiral pitch, so that the hot air can evenly pass through the opening to enter the interior of the spiral to dry the sludge; furthermore, the existence of the air inlet 412 of the screw conveyor 4 enables the hot air to be accurately introduced into the spiral conveying area. The function of the hot air is to pre-dry the sludge, reduce the water content of the sludge, improve the physical properties of the sludge, and further improve the subsequent processing efficiency.

[0094] The second feed inlet 48 provides a dedicated interface for the sludge to enter the screw conveyor 4 (a flange structure can be set at each feed inlet, air outlet, and air inlet), ensuring that the sludge can accurately and smoothly enter the screw conveyor 4 and start its conveying and treatment process. The first feed inlet 47 is connected to the conveying channel of the heat storage body. The introduction of the heat storage body can effectively utilize the waste heat temperature resources to heat the sludge during the conveying process and further dry the sludge. The reasonable layout and coordinated operation of the above-mentioned several feed inlets enable the screw conveyor 4 to integrate multiple functions during the sludge treatment process, effectively optimizing the entire sludge treatment process.

[0095] The initially dried sludge with a moisture content of 60% enters the interior of the screw conveyor 4 together with the heat storage body. During the entire conveying process of the screw conveyor 4, the heat storage body travels with the sludge. Since the heat storage body stores heat at a relatively high temperature, when it first comes into contact with the sludge, it will cause the moisture in the sludge to quickly vaporize, generating a large amount of water vapor. To further enhance the sludge drying effect, a hot air inlet (i.e., the air inlet 412) is specially set on the screw conveyor 4. The external heat source heats the air, and at the same time, it also plays a role in supplementing heat to the heat storage body. The heated air is accurately conveyed to the position of the air inlet 412 by the strong air pressure of the fan. These hot winds continuously enter the spiral interior of the screw conveyor 4 to ensure that a suitable temperature environment is always maintained inside the screw conveyor 4.

[0096] In this environment, on the one hand, the sludge makes full contact with the spiral surface of the screw conveyor 4, and heat transfer is achieved through heat conduction, and the moisture in the sludge is gradually evaporated; on the other hand, the hot air directly acts on the sludge, accelerating the sludge drying process. To timely discharge the water vapor generated during the drying process, the air outlet 49 of the screw conveyor 4 can be connected to an induced draft fan. The induced draft fan extracts the water vapor generated by drying inside the screw conveyor 4 through a specific air duct, effectively maintaining the water vapor balance inside the screw conveyor 4 and ensuring the efficient and continuous progress of the drying work, thereby achieving a better drying treatment of the sludge.

[0097] In one embodiment, as Figure 8 shown, the heat source device 5 includes a steam generator 51 and a heating reaction kettle 52. The steam generator 51 is connected to the upper half of the heating reaction kettle 52 through a steam pipe 57. Electric ball valves 53 are provided between the upper half and the lower half of the heating reaction kettle 52 and below the lower half of the heating reaction kettle 52; the lower half of the heating reaction kettle 52 is connected to the inlet of the screening machine 54, the outlet of the screening machine 54 is respectively connected to a plurality of collectors 55, and the discharge ports of each collector 55 are connected to the input end of the conveying device 56. The output end of the conveying device 56 is connected to the first feed inlet 47 of the screw conveyor 4.

[0098] The structure is as Figure 9As shown in the figure, the heating reactor 52 is divided into two parts: an inner chamber 521 and an outer chamber 522. The inner chamber 521 mainly heats the heat storage body, and an exhaust port 523 is provided at the top of the inner chamber 521. The outer chamber 522 serves as a steam circulation channel (steam enters from the steam inlet 524 and exits from the steam outlet 525. The discharged steam exchanges heat with the heat exchanger, heats the air, and then is transmitted to the hot air blower for hot air utilization), so as to heat the inner chamber 521 through steam for heat exchange. That is, the steam from the steam generator 51 enters the steam pipeline and reaches the outer chamber 522 of the heating reactor 52 to heat the heat storage body in the upper half of the heating reactor 52. After a period of time, when the temperature of the heat storage body reaches the designed temperature, the electric ball valve 53 between the upper half and the lower half of the heating reactor 52 is opened, so that the heat storage body enters the lower half of the heating reactor 52. When all the heat storage bodies in the upper half of the heating reactor 52 have fallen into the lower half of the heating reactor 52, the conveying device 56 is started to convey the heat storage body to the upper half of the heating reactor 52 for heating, and the heat storage body is circularly heated. When all the heat storage bodies in the lower half of the heating reactor 52 have completely fallen, the heat storage bodies in the upper half of the heating reactor 52 reach the designed temperature, and then the above-mentioned operation is repeated to achieve the purpose of continuous heating and continuous operation.

[0099] In order to further illustrate the municipal sludge drying method provided by the present invention, an example is given below.

[0100] The incoming sludge (with a water content of 80%) is transported to the sludge storage tank 1, and PAM is added to condition the liquid in the sludge storage tank 1. The sludge is diluted to a water content of 93% by the stirrer 11 in the sludge storage tank 1; after adding the reagent, the stirrer 11 stirs for 10 minutes and then stops stirring, waiting for the sludge to stratify and coagulate. After the sludge stratifies, it is transported to the belt filter press 3 by the pump group. Through the preliminary drying of the belt filter press 3, the final products, namely the water liquid and the sludge (with a water content of 60%), are formed. The water liquid returns to the sludge storage tank 1 for continued use.

[0101] The sludge after being pressed by the belt filter press 3 enters the screw conveyor 4 for material drying; the sludge and the heat storage body enter the screw conveyor 4 together through the feed inlet of the screw conveyor 4; after the sludge is crushed and extruded in the screw conveyor 4 and heat exchange occurs between the heat storage body and the sludge, a large amount of water in the sludge is evaporated to obtain sludge with a lower water content. The sludge falls from the second discharge port 411 of the screw conveyor 4, and the heat storage body falls from the first discharge port 410 of the screw conveyor 4. The heat storage body re-enters the heating reactor 52 through the conveying device 56 for heat treatment. The dried sludge can be incinerated together with other flammable materials to utilize the value of the sludge, and the residue after incineration is transported to the brick factory as brick-making materials.

[0102] In addition, it should be noted that the orientation or positional relationship indicated by "up and down" in this application is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of simplified description and understanding, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0103] The various embodiments in this specification are described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other. Any combination of all the embodiments provided by the present invention falls within the protection scope of this invention and will not be elaborated herein.

[0104] The municipal sludge drying method and its sludge treatment system provided by the present invention have been introduced in detail above. Specific examples are used herein to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A municipal sludge drying method, characterized in that: include: Transporting the sludge to a sludge storage tank (1), adding reagents to condition the liquid in the sludge storage tank (1), stirring the sludge, and waiting for the sludge to be stratified and agglomerated to form flocculent sludge; Conveying the flocculent sludge to a belt filter press (3) to preliminarily dehydrate the sludge; The sludge after preliminary dehydration is conveyed to a screw conveyor (4). At the same time, hot air is introduced into the screw conveyor (4) and a heat storage body is added to perform preliminary drying on the sludge.

2. The municipal sludge drying method according to claim 1, characterized in that: The step of conveying the sludge to the sludge storage tank (1), adding reagents to condition the liquid in the sludge storage tank (1), stirring the sludge, and waiting for the sludge to be stratified and agglomerated to form flocculent sludge comprises: The pump group transports the sludge to the sludge storage tank (1), adds PAM into the sludge storage tank (1) to condition the liquid in the sludge storage tank (1), controls the mixer (11) in the sludge storage tank (1) to stir the sludge, stops stirring after stirring for a preset time, and waits for the sludge to stratify and coagulate.

3. The municipal sludge drying method according to claim 1, characterized in that: The step of conveying the flocculent sludge to the belt filter press (3) to preliminarily dehydrate the sludge comprises: The pump group transports the flocculent sludge to the belt filter press (3) to preliminarily dehydrate the sludge, and the separated water liquid flows back to the sludge storage tank (1).

4. The municipal sludge drying method according to any one of claims 1 to 3, characterized in that: The step of introducing hot air into the screw conveyor (4) and adding a heat storage body comprises: The steam generator (51) passes high-temperature steam into the heating reaction kettle (52) to heat the heat storage body, and transports the heat storage body to the first feed port (47) of the screw conveyor (4) and into the screw conveyor (4). At the same time, the hot air generated when the steam generator (51) is in operation is transported to the air inlet (412) of the screw conveyor (4) and into the screw conveyor (4).

5. The municipal sludge drying method according to claim 4, characterized in that: The sludge is initially dried, and then the method comprises: The sludge falls from the second discharge port (411) of the screw conveyor (4), and the heat storage body falls from the first discharge port (410) of the screw conveyor (4). The separated heat storage body is transported to the upper half of the heating reactor (52) for heating. The separated sludge is transported to the next process, or the separated sludge is transported back to the screw conveyor (4). The sludge after preliminary dehydration is transported to the screw conveyor (4). At the same time, hot air is introduced into the screw conveyor (4), and the heat storage body is added to perform a preliminary drying step on the sludge.

6. The municipal sludge drying method according to claim 5, characterized in that: The steam generator (51) passes high-temperature steam into the heating reaction kettle (52) to heat the heat storage body, comprising: The steam from the steam generator (51) reaches the upper half of the heating reaction kettle (52) through a pipeline to heat the heat storage body in the upper half of the heating reaction kettle (52); when the heat storage body reaches a preset temperature after a preset heating time, the electric ball valve below the upper half of the heating reaction kettle (52) is opened, and the heated heat storage body enters the lower half of the heating reaction kettle (52) through the electric ball valve; when the heat storage body in the upper half has completely fallen to the lower half of the heating reaction kettle (52), the conveying device (56) conveys part of the heat storage body that needs to be heated to the upper half of the heating reaction kettle (52); The electric ball valve at the lower half of the heating reaction kettle (52) is opened, and the heated heat storage body enters the screening machine to screen the heat storage bodies of different specifications into different collectors to obtain the heat storage bodies of different mixing ratios; When the heat storage body in the lower half of the heating reaction kettle (52) has completely fallen off and the heat storage body in the upper half of the heating reaction kettle (52) has reached the preset temperature, the above two operation steps are returned to continuously heat the heat storage body.

7. The municipal sludge drying method according to claim 5, characterized in that: The sludge after the transportation and separation enters the next process, including: The separated sludge is transported to the steam generator (51) to be mixed with combustible materials for incineration, and the residue of the sludge after incineration is transported to a brick factory for brick making.

8. The municipal sludge drying method according to any one of claims 1 to 3, characterized in that: The method further comprises: after the preliminary drying of the sludge, an induced draft fan introduces the odor generated during the preliminary drying of the sludge to a biological filter tank, wherein the odor stays in the biological filter tank for at least 21 seconds, so as to remove the odor in the biological filter tank.

9. A sludge treatment system, applicable to the municipal sludge drying method according to any one of claims 1 to 8, characterized in that: include: A sludge storage tank (1) having a mixer (11) disposed therein; A pharmaceutical machine (2) for preparing reagents for conditioning the liquid in the sludge storage tank (1), wherein a drug outlet end of the pharmaceutical machine (2) is connected to a drug addition end of the sludge storage tank (1); A belt filter press (3), which is used to perform preliminary dehydration on the sludge, and whose feed port is connected to the discharge port of the sludge storage tank (1); A screw conveyor (4), which is used for preliminarily drying the sludge, and whose feed port is connected to the discharge port of the belt filter press (3); A heat source device (5) is used to heat the heat storage body and generate hot air, wherein the discharge port is connected to the first feed port (47) of the screw conveyor (4), and the air outlet of the heat source device (5) is connected to the air inlet (412) of the screw conveyor (4).

10. The sludge treatment system according to claim 9, characterized in that: The heat source device (5) comprises a steam generator (51) and a heating reaction kettle (52); the steam generator (51) is connected to the upper half of the heating reaction kettle (52) via a steam pipe (57); an electric ball valve (53) is provided between the upper half of the heating reaction kettle (52) and the lower half of the heating reaction kettle (52), and below the lower half of the heating reaction kettle (52); The lower half of the heating reaction kettle (52) is connected to the inlet of the screening machine (54), and the outlet of the screening machine (54) is respectively connected to a plurality of collectors (55), and the discharge port of each collector (55) is connected to the input end of the conveying device (56), and the output end of the conveying device (56) is connected to the first feed port (47).

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