Pyrolysis carbonization treatment system for sludge and carbonization treatment method thereof

Abstract

The invention discloses a pyrolysis carbonization treatment system for sludge and a carbonization treatment method thereof. The pyrolysis carbonization treatment system comprises a sludge pretreatment device, a multi-section carbonization furnace and a tail gas treatment device which are communicated in sequence, the sludge pretreatment device comprises a plate-and-frame filter press and a paddle dryer which are connected with each other; a combustion-supporting device for receiving drying tail gas and supporting combustion for the multi-section carbonization furnace is arranged at the top of the paddle dryer; the multi-section carbonization furnace comprises a drying layer, a carbonization layer and an activation layer which are communicated from top to bottom, and a steam injector for injecting steam into the activation layer and a combustor for secondarily heating the activation layer are mounted on the outer wall of the multi-section carbonization furnace; compared with the prior art, the separation between the drying tail gas and the sludge is realized through the paddle dryer, the generated drying tail gas is supplied to the multi-section carbonization furnace for combustion under the action of the combustion-supporting device, and the anoxic combustion in the multi-section carbonization furnace is realized under the action of limited sludge gas, so that the carbonization requirement of the sludge in the multi-section carbonization furnace is met; and the sludge in the multi-section carbonization furnace is pyrolyzed, carbonized and activated.

Description

Technical Field

[0001] The present invention relates to the technical field of sludge treatment, and in particular to a pyrolysis carbonization treatment system for sludge and a carbonization treatment method thereof. Background Art

[0002] Sludge usually refers to semi-solid or solid waste generated during the sewage treatment process. It contains a large amount of water, organic matter, pathogens, heavy metals and harmful chemicals. It mainly comes from urban sewage treatment, industrial wastewater treatment, river dredging, etc. Sludge usually contains 70%-99% water, organic matter, inorganic matter and pollutants.

[0003] Sludge treatment is usually divided into landfill and incineration. Landfill is done by dehydrating the sludge before burying it, but this method is prone to cause environmental pollution. Although incineration reduces environmental pollution, it also has the problem of high cost and the need for tail gas treatment.

[0004] Chinese publication number CN214571448U discloses a sludge pyrolysis treatment system based on a multi-stage furnace, including a sludge pyrolysis treatment system and a pyrolysis tail gas treatment system. The sludge pyrolysis treatment system includes a sludge storage tank, a paddle dryer, a feed elevator, a multi-stage pyrolysis furnace, a drum cooler, a discharge elevator and a discharge storage tank for sequentially transporting the sludge; the tail gas treatment system is used to treat the tail gas after sludge pyrolysis, including a secondary combustion furnace, a waste heat boiler, an economizer, a bag dust collector, a precooler, a washing tower, a biological deodorization tower, an induced fan and a chimney connected in sequence from the tail gas discharge port of the multi-stage pyrolysis furnace.

[0005] The above-disclosed sludge pyrolysis treatment system simply incinerates and dries the sludge through a multi-stage pyrolysis furnace, but does not provide any instructions for discharging the dried material. In addition, the above-disclosed sludge pyrolysis treatment system simply incinerates and dries the sludge, resulting in a waste of resources and being detrimental to the recycling of resources. Summary of the Invention

[0006] The present invention aims to overcome the above-mentioned defects in the prior art and provide a pyrolysis carbonization treatment system and a carbonization treatment method for sludge which have good treatment effect and can realize resource recycling.

[0007] In order to achieve the above-mentioned object, the present application adopts the following technical scheme: A pyrolysis carbonization treatment system for sludge comprises a sludge pretreatment device, a multi-section carbonization furnace and a tail gas treatment device which are sequentially connected; the sludge pretreatment device, the multi-section carbonization furnace and the tail gas treatment device form a closed internal circulation structure during use; the sludge pretreatment device is provided with a combustion-supporting device for receiving dry tail gas and supplying oxygen to the multi-section carbonization furnace; the multi-section carbonization furnace is supplied with oxygen by the combustion-supporting device only; the tail gas treatment device is provided with a heat supply circuit for supplying heat to the sludge pretreatment device and a steam injector for supplying steam to the multi-section carbonization furnace; the multi-section carbonization furnace is sequentially connected with a drying layer, a carbonization layer and an activation layer from top to bottom; the steam injector is arranged corresponding to the activation layer, and the multi-section carbonization furnace is further provided with a burner on the outer wall thereof for secondary heating of the activation layer; and the tail gas treatment device comprises a secondary furnace, a waste heat boiler, a bag-type dust collector and a multi-section washing tower which are sequentially connected.

[0008] As a preferred scheme of the present application, the sludge pretreatment device comprises a plate-and-frame filter press and a paddle dryer which are connected, and the combustion-supporting device is connected to the top of the paddle dryer.

[0009] As a preferred scheme of the present application, the steam injector and the heat supply circuit are connected to the waste heat boiler, and the heat supply circuit is connected to the paddle dryer.

[0010] As a preferred scheme of the present application, the multi-section carbonization furnace comprises a furnace body and a central shaft which is rotatably arranged in the middle of the furnace body, and a plurality of furnace beds are arranged in the furnace body in stages from top to bottom; a rake arm corresponding to the position of the furnace bed is arranged on the central shaft; and rake teeth for uniformly laying sludge on the furnace bed are arranged on the rake arm.

[0011] As a preferred scheme of the present application, the drying layer, the carbonization layer and the activation layer are divided according to the height of the furnace bed from top to bottom, and the steam injector and the burner are arranged corresponding to the position of the furnace bed in the activation layer.

[0012] As a preferred scheme of the present application, the furnace bed is arranged in a direction of being inclined upward from the outside to the inside of the furnace body, and a plurality of discharge ports arranged alternately are formed on the inner and outer sides of the furnace beds from top to bottom; and the rake teeth are formed in a curved structure for pushing the sludge to the discharge ports.

[0013] As a preferred scheme of the present application, the waste heat boiler is connected to the paddle dryer and the steam injector.

[0014] As a preferred scheme of the present application, a conveying device for conveying the pretreated sludge is arranged between the sludge pretreatment device and the multi-section carbonization furnace.

[0015] A carbonization treatment method of a pyrolysis carbonization treatment system for sludge based on the pyrolysis carbonization treatment system for sludge, comprising the following steps: Step A: connecting the silo for storing sludge, the plate-and-frame filter press, the paddle dryer and the multi-stage carbonization furnace through the conveying pipeline, wherein the conveying pipeline between the silo and the plate-and-frame filter press is provided with a conveying pump for conveying the sludge to the plate-and-frame filter press, and the sludge is dewatered to a water content of 60% or less under the action of the plate-and-frame filter press to form a filter cake; Step B: conveying the formed filter cake to the paddle dryer through the conveying pipeline, reducing the water content of the filter cake to 25%-35% under the action of the conductive heating of the paddle dryer to form a granular structure, and providing a crushing granulator on the conveying pipeline between the paddle dryer and the multi-stage carbonization furnace for processing the powder-shaped sludge into a certain particle shape, and purifying the gas generated by the paddle dryer under the action of the combustion-supporting device and inputting the multi-stage carbonization furnace; Step C: conveying the granular sludge generated by the crushing granulator to the top of the multi-stage carbonization furnace through the pneumatic conveying device, and the granular sludge entering the multi-stage carbonization furnace passes through a drying layer, a carbonization layer and an activation layer in sequence, and the multi-stage carbonization furnace has and only has the combustion-supporting device to supply oxygen, the sludge starts to carbonize in an oxygen-deficient environment after entering the carbonization layer, and the carbonized sludge undergoes a water gas reaction under the action of secondary high temperature and steam, wherein the fully reacted sludge forms activated carbon, and the unreacted sludge forms biochar and sludge carbon; Step D: the flue gas generated by the multi-stage carbonization furnace enters the tail gas treatment device, is fully combusted in a secondary furnace, and the heat generated by the full combustion is recovered as heat energy under the action of a waste heat boiler, and the steam generated by the waste heat boiler is supplied to the paddle dryer and the activation layer; Step E: further purifying the tail gas under the action of a bag-type dust collector and a multi-stage washing tower until it is discharged.

[0016] As a preferred scheme of the present application, after the sludge is fully reacted to form activated carbon, oxygen is injected into the activation layer to make the unreacted sludge burn in the activation layer.

[0017] As a preferred scheme of the present application, the plate-and-frame filter press, the paddle dryer, the multi-stage carbonization furnace, the secondary furnace and the waste heat boiler form an internal circulation structure.

[0018] Compared with the prior art, by forming a closed internal circulation structure inside the sludge pretreatment device, multi-stage carbonization furnace and tail gas treatment device, the gas impurities generated by the sludge pretreatment device are used to supply oxygen to the multi-stage carbonization furnace, the internal combustion of the multi-stage carbonization furnace realizes sufficient combustion of the gas impurities generated by the sludge pretreatment device, the steam generated by the tail gas treatment device realizes heat supply to the sludge pretreatment device and steam supply to the multi-stage carbonization furnace, the recycling utilization of resources is realized, and the overall structure is in a closed structure during use, all substances generated by the sludge pretreatment device and the multi-stage carbonization furnace are treated by the tail gas treatment device, and standardized control of emissions is realized. The dehydration and drying of sludge is realized by the paddle dryer, the separation between sludge gas and sludge is realized, and the dry tail gas generated under the action of the combustion supporting device is supplied to the multi-stage carbonization furnace for combustion, the oxygen-deficient combustion in the multi-stage carbonization furnace is realized under the action of the limited dry tail gas, the carbonization requirements of sludge in the multi-stage carbonization furnace are met, the pyrolysis and carbonization activation of sludge in the multi-stage carbonization furnace are realized, the energy recovery in sludge is realized, and the utilization and recovery of different tail gases in the process of pyrolysis and carbonization activation of sludge are realized under the action of the combustion supporting device and the tail gas treatment device, and the overall resource utilization is efficient. Most of the water in the sludge is removed through the plate and frame filter press and the paddle dryer, and after pipeline transportation, the sludge is more compact before entering the multi-stage carbonization furnace, and is not easy to break and pulverize in the drying process of the subsequent drying layer, so that the proportion of particle size of the sludge is large when the sludge enters the carbonization layer and the activation layer, and the carbonization yield and product quality in the carbonization and activation process are closer to the particle activated carbon. The multi-stage carbonization furnace with an integrated structure is divided into a drying layer, a carbonization layer and an activation layer from top to bottom, and the steam of the drying layer and the paddle dryer is used for activation of the multi-stage carbonization furnace, and an internal circulation closed structure is formed, so that the oxygen-deficient treatment of sludge in the carbonization and activation states is met. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 is a structural schematic diagram of the present application; Fig. 2 is a connection schematic diagram of the control handle and the adjusting mechanism; Fig. 3 is an installation schematic diagram of the conveying pipeline; The plate and frame filter press 1, the paddle dryer 2, the combustion supporting device 3, the multi-stage carbonization furnace 4, the furnace body 41, the drying layer 42, the carbonization layer 43, the activation layer 44, the center shaft 45, the furnace bed 46, the discharge port 461, the rake arm 47, the rake tooth 471, the burner 48, the steam injector 49, the secondary furnace 5, the waste heat boiler 6, the bag-type dust collector 7, the multi-stage washing tower 8, the discharge chimney 9, the stock bin 10, the conveying pipeline 11, the conveying pump 12, the crushing granulator 13 and the heat supply circuit 14. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0021] like Figs. 1-3 As shown, a pyrolysis carbonization treatment system for sludge comprises a sludge pretreatment device, a multi-stage carbonization furnace 4 and an exhaust gas treatment device which are connected in sequence; a closed internal circulation structure is formed inside the sludge pretreatment device, the multi-stage carbonization furnace 4 and the exhaust gas treatment device, the sludge pretreatment device is provided with a combustion-supporting device 3 for receiving the dried exhaust gas and supplying oxygen to the multi-stage carbonization furnace 4, the multi-stage carbonization furnace 4 has only the combustion-supporting device 3 for supplying oxygen, and the exhaust gas treatment device is provided with a combustion-supporting device 3 for supplying oxygen to the sludge pretreatment device A heating circuit 14 for supplying heat and a steam injector 49 for supplying steam to the multi-stage carbonization furnace 4; the multi-stage carbonization furnace 4 is connected to a drying layer 42, a carbonization layer 43 and an activation layer 44 in sequence from top to bottom, the steam injector 49 is arranged corresponding to the activation layer 44, and a burner 48 for secondary heating of the activation layer 44 is also provided on the outer wall of the multi-stage carbonization furnace 4; the exhaust gas treatment device includes a secondary furnace 5, a waste heat boiler 6, a bag dust collector 7 and a multi-stage washing tower 8 connected in sequence.

[0022] The multi-stage carbonization furnace 4 is an integrated structure. The drying layer 42, the carbonization layer 43 and the activation layer 44 centrally treat the sludge in the multi-stage carbonization furnace 4, so that the sludge is dried, carbonized and activated in sequence under the action of the same multi-stage carbonization furnace 4. The drying layer 42, the carbonization layer 43 and the activation layer 44 arranged in sequence from top to bottom also conform to the way the material moves from top to bottom. The drying layer 42 is located at the top of the multi-stage carbonization furnace 4. The steam generated by the drying layer 42 does not affect the carbonization layer 43 and the activation layer 44 under the action of the rising hot air.

[0023] The water content of sludge is usually as high as 80%-99%. Under the squeezing action of the plate and frame filter press 1, the sludge is partially dehydrated and squeezed into a filter cake structure. A filter cake dragon is provided at the discharge port of the plate and frame filter press 1 for conveying the filter cake to the filter cake silo. The paddle dryer 2 is a double-shaft dryer that uses heat conduction as the main means of heat exchange. It relies on the heat from the hot wall of the double-shaft dryer to contact, stir and squeeze the sludge particles for heat exchange. Under the indirect conduction heating effect of the paddle dryer 2, the paddle dryer 2 does not carry away the heat with air. The heat is used to heat the material. The only heat loss is the heat dissipation to the environment through the insulation layer of the device body.

[0024] The rotating shaft of the paddle dryer 2 is densely arranged with wedge-shaped paddles, and the heat transfer surface of the wedge-shaped paddles has a self-cleaning function. The relative movement of the sludge particles and the wedge-shaped surface produces a scrubbing effect, which can scrub off the adhered materials on the wedge-shaped surface, so that the heat transfer surface is always kept clean during operation. After the sludge is dried by the paddle dryer 2, it is transported to the high-level silo for temporary storage through the pneumatic conveying device.

[0025] The combustion supporting device 3 includes a drying spray tower, a plate condenser and a drying fan connected in sequence. During the drying process of the sludge in the paddle dryer 2, tail gas containing a certain amount of water vapor and sludge dust is generated. The tail gas is sucked by the drying fan, sprayed by the drying spray tower, cooled and dedusted, then cooled and condensed by the plate condenser, and finally enters the combustion system as combustion supporting air to completely solve the pollution problem of indirect drying tail gas.

[0026] The multi-stage carbonization furnace 4 includes a furnace body 41 and a central shaft 45 rotatably arranged in the middle of the furnace body 41. The furnace body 41 is provided with a plurality of furnace beds 46 arranged from top to bottom. The central shaft 45 is provided with rake arms 47 corresponding to the positions of the furnace beds 46. The rake arms 47 are provided with rake teeth 471 for uniformly laying the sludge on the furnace beds 46.

[0027] The bottom of the multi-stage carbonization furnace 4 is provided with a motor for driving the rotation of the central shaft 45. Under the action of the rotation of the central shaft 45, the rake arms 47 and the rake teeth 471 are synchronously rotated, so that the rake teeth 471 are moved on the surface of the furnace bed 46.

[0028] The drying layer 42, the carbonization layer 43 and the activation layer 44 are divided according to the height of the furnace bed 46 from top to bottom. The injector and the burner 48 are arranged corresponding to the position of the furnace bed 46 in the activation layer 44.

[0029] The feed inlet of the multi-stage carbonization furnace 4 is located at the top of the multi-stage carbonization furnace 4. Under the action of the drying layer 42, the carbonization layer 43 and the activation layer 44 arranged from top to bottom, the sludge is moved by the rake teeth 471 in sequence.

[0030] After the sludge is fed, it is uniformly distributed on the surface of the furnace bed 46 under the action of the rake teeth 471 of the rake arms 47. The rake teeth 471 rake the sludge to increase the contact area between the sludge and the furnace bed 46 to promote heat transfer and mass transfer rate.

[0031] The furnace bed 46 is arranged upwardly inclined from the outside to the inside of the furnace body 41. The inside and outside of the plurality of furnace beds 46 from top to bottom form alternatingly arranged discharge ports 461. The rake teeth 471 form a curved structure for moving the sludge to the discharge port 461.

[0032] Under the action of the alternately arranged discharge ports 461, the moving path of the extended sludge in the falling process is prolonged, thereby ensuring the heating of the sludge in the drying layer 42, the carbonization layer 43 and the activation layer 44.

[0033] The drying layer 42, the carbonization layer 43 and the activation layer 44 are all in a heating state of the sludge. Under the action of the burner 48, the temperature at the activation layer 44 is higher than that at the drying layer 42 and the carbonization layer 43, and since the carbonization layer 43 is arranged close to the activation layer 44, the temperature at the drying layer 42, the carbonization layer 43 and the activation layer 44 gradually increases from top to bottom.

[0034] Under the heating action of the drying layer 42, the water remaining in the sludge is separated from the sludge in the form of steam. The dried sludge moves downward into the carbonization layer 43 under the action of the rake teeth 471. At this time, the organic matter in the sludge begins to carbonize in an oxygen-deficient environment, and the low-volatility substances and hydrogen and oxygen elements in the organic matter are removed according to the composition ratio of water, leaving black carbon, thereby carbonizing the sludge. The carbonized sludge moves downward into the activation layer 44 under the action of the rake teeth 471. The temperature in the activation layer 44 is increased to 800-1000℃ under the action of the burner 48. At this time, steam is injected into the activation layer 44, and the steam and the carbon in the carbonized sludge react to produce water gas: C+H2O→CO+H2.

[0035] The steam generated by the drying layer 42 and the paddle dryer 2 is used to inject into the activation layer 44, without the need for additional steam transportation from the outside, thereby ensuring the overall sealing of the multi-stage carbonization furnace 4 and creating conditions for the sealing of the carbonization layer 43 and the activation layer 44.

[0036] Part of the carbon in the carbonized sludge reacts with water vapor to produce carbon monoxide and hydrogen, completing the activation and forming fine pores on the surface, thereby preparing activated carbon. The remaining part is biochar and sludge carbon. The biochar is the sludge that has not reacted in the activation layer 44 after carbonization in the carbonization layer 43, and the sludge carbon is the sludge that has not been carbonized in an oxygen-deficient environment and has not reacted in the activation layer 44.

[0037] The sludge carbon retains part of the organic matter and nutrient elements because it has not been carbonized in an oxygen-deficient environment. The sludge carbon can be used as a soil conditioning agent, and can be mixed into cement as a cement aggregate / additive. The heavy metals in the sludge carbon are solidified by the mineral phase, without the risk of secondary release.

[0038] The biochar is carbonized in the carbonization layer 43, and a carbonized surface is formed on the surface of the biochar, which can adsorb the heavy metals and organic matter in the sludge carbon.

[0039] The activated carbon after regeneration is discharged from the bottom of the multi-stage carbonization furnace 4 through the discharge hole, cooled by the slag cooler, and then transported into the finished product bin through the pneumatic conveying system. The flue gas from the top of the multi-stage carbonization furnace 4 is sent to the tail gas treatment device for heat recovery and pollutant treatment.

[0040] The secondary furnace 5 is connected to the top of the multi-stage carbonization furnace 4, and sufficient air and auxiliary fuel are introduced into the secondary furnace 5 to heat the flue gas to above 850℃ and stay for 2s, so that the volatile matter and pyrolysis gas in the flue gas are completely converted into harmless CO2 and H2O, and harmful substances such as dioxin are destroyed.

[0041] The secondary furnace 5 is connected to the top of the multi-stage carbonization furnace 4, and sufficient air and auxiliary fuel are introduced into the secondary furnace 5 to heat the flue gas to above 850℃ and stay for 2s, so that the volatile matter and pyrolysis gas in the flue gas are completely converted into harmless CO2 and H2O, and harmful substances such as dioxin are destroyed.

[0042] The flue gas after waste heat utilization by the waste heat boiler 6 is cooled to below 200℃, and then enters the bag filter 7 for removal of particulate matter.

[0043] The bag filter 7 adopts a new type of circular structure, and the main part of the filter system of the bag filter 7 adopts a circular design with tangential air inlet and no dead angle. The bag filter 7 includes a flue gas conveying pipeline, a pulse backwashing process, a filtration and dust removal system, a residue collection system, etc.

[0044] The key of the bag filter 7 is a reasonable electrical control system. The pulse jet pipe randomly and sequentially performs pulse backwashing filtration, so that the dust removal effect reaches dust≤10mg / Nm3. At the same time, under normal load during operation, the maximum pressure difference of the backwashing process is maintained below 1.2kpa, and the operation is reliable. The filter bag backwashing ash removal performance is excellent. The bottom of the dust remover is flat, and a rotary scraper system is used for forced ash removal, which can clean the dust at the bottom in real time and avoid dust accumulation.

[0045] The multi-stage washing tower 8 includes a plurality of washing towers connected in sequence. The number of washing towers and the specific washing method are set according to actual conditions. The pollutants in the flue gas are removed through the multi-stage washing tower to meet the emission standard.

[0046] A carbonization treatment method for a sludge pyrolysis carbonization treatment system, based on a sludge pyrolysis carbonization treatment system, comprising the following steps: Step A: the formed filter cake is transported to the paddle dryer 2 through the conveying pipe 11, and the moisture content of the filter cake is reduced to 25%-35% under the conductive heating of the paddle dryer 2, forming a granular structure, and a crushing granulator 13 for processing the powdery sludge into a certain particle shape is arranged on the conveying pipe 11 between the paddle dryer 2 and the multi-stage carbonization furnace 4, and the gas generated by the paddle dryer 2 is purified under the action of the combustion-supporting device 3 and then input into the multi-stage carbonization furnace 4.

[0047] Step B: the formed filter cake is transported to the paddle dryer 2 through the conveying pipe 11, and the moisture content of the filter cake is reduced to 25%-35% under the conductive heating of the paddle dryer 2, forming a granular structure, and a crushing granulator 13 for processing the powdery sludge into a certain particle shape is arranged on the conveying pipe 11 between the paddle dryer 2 and the multi-stage carbonization furnace 4, and the gas generated by the paddle dryer 2 is purified under the action of the combustion-supporting device 3 and then input into the multi-stage carbonization furnace 4, which serves as combustion-supporting air for the multi-stage carbonization furnace 4, and the amount of the gas is effective, ensuring that the organic matter in the sludge begins to carbonize under anoxic conditions when the sludge is in the carbonization layer 43, and the low-volatility substances and hydrogen and oxygen elements in the organic matter are removed according to the composition ratio of water, leaving black carbon, thereby carbonizing the sludge.

[0048] After passing through the paddle dryer 2, the sludge is dried, and the solid and gas are separated, realizing the secondary use of the gas without causing the sludge to overflow.

[0049] The sludge in the present application is dried by the plate-and-frame filter press 1 and the paddle dryer 2, and after being transported through the pipe, the sludge is more compact before entering the multi-stage carbonization furnace 4, and is not easy to break and powderize during the drying process in the subsequent drying layer 42, ensuring that the particle size of the sludge accounts for a large proportion when the sludge enters the carbonization layer 43 and the activation layer 44, and the carbonization yield and product quality during the carbonization and activation process are closer to granular activated carbon.

[0050] A conveying pipe for transporting the sludge is arranged between the paddle dryer 2 and the multi-stage carbonization furnace 4, and a crushing granulator for processing the powdery sludge into a certain particle shape is arranged on the conveying pipe, thereby increasing the particle size of the sludge and improving the flowability of the sludge in the conveying pipe, facilitating the transportation and subsequent processing of the sludge.

[0051] Step C: The granular sludge produced by the crushing granulator 13 is transported to the top of the multi-stage carbonization furnace 4 by the pneumatic conveying device, and the granular sludge entering the multi-stage carbonization furnace 4 successively passes through the drying layer 42, the carbonization layer 43 and the activation layer 44, and the multi-stage carbonization furnace 4 is supplied with oxygen by the combustion-supporting device 3 only, the sludge starts to carbonize in an oxygen-deficient environment after entering the carbonization layer 43, and the carbonized sludge undergoes a water gas reaction under the action of secondary high temperature and steam, wherein the fully reacted sludge forms activated carbon, and the incompletely reacted sludge forms biochar and sludge carbon.

[0052] After the sludge is fully reacted to form activated carbon, air is injected into the activation layer 44 to make the incompletely reacted sludge burn in the activation layer 44, so that no biochar and sludge carbon are formed under the action of complete combustion, and effective incineration of the carbonized sludge is realized.

[0053] The activation layer 44 is provided with a pipeline through which air can be introduced, and the pipeline switch is set according to actual needs, when the pipeline is in a closed state, the carbonized sludge undergoes a water gas reaction under the action of secondary high temperature and steam, wherein the fully reacted sludge forms activated carbon, and the incompletely reacted sludge forms biochar and sludge carbon.

[0054] When the pipeline is in an open state, part of the sludge fully reacts to form activated carbon, and the other sludge is fully incinerated, and the oxygen supply amount of the pipeline is matched according to the total sludge amount.

[0055] Step D: The flue gas produced by the multi-stage carbonization furnace 4 enters the tail gas treatment device, is fully combusted in the secondary furnace 5, and the heat generated by the full combustion is recovered by the waste heat boiler 6, and the steam produced by the waste heat boiler 6 is supplied to the paddle dryer 2 and the steam injector 49.

[0056] Step E: The tail gas is further purified under the action of the bag-type dust collector 7, the multi-stage washing tower and the demister until it is discharged.

[0057] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application; therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0058] Although the present invention is described in more detail using the following terms: plate-and-frame filter press 1, paddle dryer 2, combustion-supporting device 3, multi-stage carbonization furnace 4, furnace body 41, drying layer 42, carbonization layer 43, activation layer 44, central shaft 45, furnace bed 46, discharge port 461, rake arm 47, rake tooth 471, burner 48, steam injector 49, secondary furnace 5, waste heat boiler 6, bag-type dust collector 7, multi-stage washing tower 8, exhaust stack 9, stock bin 10, conveying pipeline 11, conveying pump 12, crushing and granulating machine 13, heat supply circuit 14, etc., the use of other terms is not excluded. The use of these terms is merely for the convenience of describing and explaining the essence of the present invention; any interpretation of them as an additional limitation is contrary to the spirit of the present invention.

Claims

1. A pyrolysis carbonization treatment system for sludge, comprising a sludge pretreatment device, a multi-stage carbonization furnace (4) and an exhaust gas treatment device connected in sequence; characterized in that, A closed internal circulation structure is formed inside the sludge pretreatment device, the multi-stage carbonization furnace (4) and the tail gas treatment device. The sludge pretreatment device is provided with a combustion-supporting device (3) for receiving dried tail gas and supplying oxygen to the multi-stage carbonization furnace (4). The multi-stage carbonization furnace (4) has and only has the combustion-supporting device (3) for supplying oxygen. The tail gas treatment device is provided with a heating circuit (14) for supplying heat to the sludge pretreatment device and a steam injector (49) for supplying steam to the multi-stage carbonization furnace (4). The multi-stage carbonization furnace (4) has a drying layer (42), a carbonization layer (43) and an activation layer (44) connected in sequence from top to bottom. The steam injector (49) is arranged corresponding to the activation layer (44), and a burner (48) for secondary heating the activation layer (44) is also provided on the outer wall of the multi-stage carbonization furnace (4). The tail gas treatment device includes a secondary furnace (5), a waste heat boiler (6), a bag dust collector (7) and a multi-stage washing tower (8) connected in sequence.

2. A pyrolysis carbonization treatment system for sludge according to claim 1, characterized in that: The sludge pretreatment device comprises a plate and frame filter press (1) and a paddle dryer (2) connected to each other, and a combustion-supporting device (3) is connected to the top of the paddle dryer (2).

3. A pyrolysis carbonization treatment system for sludge according to claim 2, characterized in that: The steam injector (49) and the heating circuit (14) are connected to the waste heat boiler (6), and the heating circuit (14) is connected to the paddle dryer (2).

4. The pyrolysis carbonization treatment system for sludge according to claim 1, characterized in that: The multi-stage carbonization furnace (4) includes a furnace body (41) and a central shaft (45) rotatably arranged in the middle of the furnace body (41), and a plurality of furnace beds (46) arranged in a graded manner from top to bottom are provided in the furnace body (41), a rake arm (47) corresponding to the position of the furnace bed (46) is installed on the central shaft (45), and rake teeth (471) are provided on the rake arm (47) for evenly spreading the sludge on the furnace bed (46).

5. A pyrolysis carbonization treatment system for sludge according to claim 4, characterized in that: The drying layer (42), the carbonization layer (43) and the activation layer (44) are divided according to the height of the hearth (46) from top to bottom, and the steam injector (49) and the burner (48) are arranged at the position of the hearth (46) corresponding to the activation layer (44).

6. The pyrolysis carbonization treatment system for sludge according to claim 4, characterized in that: The hearth (46) is arranged upwardly and tilted from outside to inside along the furnace body (41), and alternately arranged discharge openings (461) are formed on the inner and outer sides of the plurality of hearths (46) from top to bottom, and the rake teeth (471) are formed with a curved structure for moving the sludge toward the discharge opening (461).

7. The pyrolysis carbonization treatment system for sludge according to claim 1, characterized in that: The waste heat boiler (6) is connected to the blade dryer (2) and the steam injector (49).

8. A carbonization treatment method for a pyrolysis carbonization treatment system for sludge, characterized in that: The pyrolysis carbonization treatment system for sludge according to any one of claims 1 to 7 comprises the following steps: Step A: connecting a silo (10) for storing sludge, a plate and frame filter press (1), a paddle dryer (2), and a multi-stage carbonization furnace (4) via a conveying pipe (11), wherein the conveying pipe (11) between the silo (10) and the plate and frame filter press (1) is equipped with a conveying pump (12) for conveying the sludge to the plate and frame filter press (1), and dehydrating the sludge to a moisture content of less than 60% under the action of the plate and frame filter press (1) to form a filter cake; Step B: The formed filter cake is transported to the paddle dryer (2) through the transport pipe (11), and the moisture content of the filter cake is reduced to 25%-35% under the conductive heating effect of the paddle dryer (2), forming a granular structure. A crushing granulator (13) for processing the powdered sludge into a certain granular shape is provided on the transport pipe (11) between the paddle dryer (2) and the multi-stage carbonization furnace (4), and the gas generated by the paddle dryer (2) is purified under the action of the combustion-supporting device (3) and then input into the multi-stage carbonization furnace (4); Step C: The granular sludge produced by the crushing granulator (13) is transported to the top of the multi-stage carbonization furnace (4) by a wind conveying device. The granular sludge entering the multi-stage carbonization furnace (4) passes through the drying layer (42), the carbonization layer (43) and the activation layer (44) in sequence. The multi-stage carbonization furnace (4) has only the combustion-supporting device (3) for oxygen supply. After entering the carbonization layer (43), the sludge begins to carbonize in an oxygen-deficient environment. The carbonized sludge undergoes a water-gas reaction under the action of secondary high temperature and steam, wherein the fully reacted sludge forms activated carbon, and the incompletely reacted sludge forms biochar and sludge charcoal. Step D: The flue gas generated by the multi-stage carbonization furnace (4) enters the tail gas treatment device, is fully burned in the secondary furnace (5), and the heat generated by the full combustion is recovered by the waste heat boiler (6). The steam generated by the waste heat boiler (6) is supplied to the paddle dryer (2) and the activation layer (44); Step E: The tail gas is further purified by the bag filter (7) and the multi-stage scrubber (8) until it is discharged.

9. The carbonization treatment method for a pyrolysis carbonization treatment system for sludge according to claim 8, characterized in that: In step C, after the sludge is fully reacted to form activated carbon, oxygen is injected into the activation layer (44) to burn the incompletely reacted sludge in the activation layer (44).

10. The carbonization treatment method for a pyrolysis carbonization treatment system for sludge according to claim 8, characterized in that: The plate and frame filter press (1), the paddle dryer (2), the multi-stage carbonization furnace (4), the secondary furnace (5) and the waste heat boiler (6) form a closed internal circulation structure.

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