System and method for co-processing sludge in a cement kiln
Patent Information
- Application Number
- CN202610986992.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-03
- Publication Date
- 2026-10-09
AI Technical Summary
由于污泥本身比生料密度小，加上在烘干磨中的进一步粉磨，粒径很小，在一级旋风预热器中很难被收集进入下一级预热器，通常会以飞灰的形式进入窑尾袋收尘器，袋收尘器收集后回到生料系统，再次进入一级旋风筒造成循环富集，加上其密度小，颗粒细，容易附着在滤袋表面，造成除尘器阻力大幅提升，影响产量和能耗
[0036]1、本分离工艺技术是根据生料密度大，粒径大，污泥粉密度小，粒径小的特点，采用空气选粉的方式分离。
Smart Images
Figure CN122881337A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of sludge treatment technology, and in particular to a system and method for co-processing sludge in a cement kiln. Background Technology
[0002] When co-processing sludge from urban wastewater treatment plants in cement kilns, the dried sludge is required to be fed into a decomposition furnace or kiln tail flue for combustion and decomposition, and the moisture content of the dried sludge is required to be less than 30%.
[0003] Sludge drying is usually done by a third party. The dried sludge provided by the third party has a moisture content of 30%-80%. Sludge with a moisture content of less than 30% can be used directly, while sludge with a moisture content of more than 30% must be dried again until the moisture content is less than 30% before it can be used.
[0004] For sludge with a moisture content greater than 30%, cement plants utilize the waste heat from kiln tail flue gas for drying. This typically involves direct drying using a new dryer and dust collector system, requiring a separate drying system, equipment, personnel, processes, and complex management. Some cement plants add sludge with a moisture content greater than 30% to a drying mill along with raw materials, then feed it into the feed inlet of the primary cyclone preheater at the kiln tail. Because sludge itself has a lower density than raw materials, and further grinding in the drying mill results in very small particle sizes, it is difficult to collect in the primary cyclone preheater and transfer to the next stage. It usually enters the kiln tail baghouse dust collector as fly ash, which is then collected and returned to the raw material system, re-entering the primary cyclone, causing a cycle of enrichment. Furthermore, its low density and fine particles easily adhere to the filter bag surface, significantly increasing the dust collector resistance and impacting output and energy consumption. Summary of the Invention
[0005] To solve the above-mentioned technical problems, this invention provides a method for co-processing sludge in a cement kiln. Based on the characteristics of raw materials having high density and large particle size, and sludge powder having low density and small particle size, the dried and finely ground sludge is separated by air separation and directly fed into a decomposition furnace for combustion and decomposition.
[0006] The technical solution adopted in this invention is:
[0007] A method for co-processing sludge in a cement kiln includes the following steps:
[0008] S1. Sludge and raw materials with a moisture content of 30%-80% are conveyed to the drying mill, which grinds and dries the sludge and raw materials to obtain a mixture.
[0009] S2. The mixed materials are separated from the flue gas by a cyclone dust collector. The separated mixed materials are stored in the raw material silo for later use, and the flue gas is sent into a bag dust collector for treatment.
[0010] S3. The mixture in the raw material silo is lifted to the multi-stage cyclone preheater for preheating. After preheating, it is transported to the decomposition furnace for decomposition. The exhaust gas outlet of the multi-stage cyclone preheater is connected to the drying mill or bag dust collector.
[0011] S4. The decomposed material is discharged into a rotary kiln for sintering and the product is obtained. The hot flue gas generated by the rotary kiln and the decomposition furnace provides heat to the multi-stage cyclone preheater and the drying mill in sequence.
[0012] S5. The dust collected by the bag dust collector is sent to the air classifier for separation, separating the sludge from other raw materials. The dry sludge powder separated by the air classifier is sent to the decomposition furnace for combustion and decomposition.
[0013] Optionally, in step S3, the first-stage cyclone preheater of the multi-stage cyclone preheater is connected to a drying mill or a bag dust collector, the material outlet of the penultimate stage cyclone preheater of the multi-stage cyclone preheater is connected to a decomposition furnace, and the material outlet of the last stage cyclone preheater of the multi-stage cyclone preheater is connected to a rotary kiln.
[0014] Optionally, in step S3, the multi-stage cyclone preheater includes a first-stage cyclone preheater, a second-stage cyclone preheater, a third-stage cyclone preheater, and a fourth-stage cyclone preheater connected in sequence. The exhaust gas outlet of the first-stage cyclone preheater is connected to a drying mill or a bag dust collector, the material outlet of the third-stage cyclone preheater is connected to a decomposition furnace, and the material outlet of the fourth-stage cyclone preheater is connected to a rotary kiln.
[0015] Optionally, in step S3, the multi-stage cyclone preheater is connected to the drying mill or the multi-stage cyclone preheater is connected to the bag dust collector according to preset conditions.
[0016] Optionally, the preset condition in step S3 is to preset the start and stop time periods of the drying mill according to the peak and valley periods of the mains power supply;
[0017] When the drying mill starts, the exhaust outlet of the multi-stage cyclone preheater is connected to the drying mill, and the flue gas from the drying mill is connected to the bag dust collector after passing through the cyclone dust collector; when the drying mill is stopped, the exhaust outlet of the multi-stage cyclone preheater is connected to the bag dust collector.
[0018] Optionally, in step S5, the dust collected by the bag filter is sent to an air classifier for separation, separating the sludge from other raw materials, including the following steps:
[0019] S51. Use a classifier to separate the dust collected by the bag dust collector;
[0020] S52. The sorted raw materials are sent to the raw material silo or multi-stage cyclone preheater;
[0021] S53. The sludge enters the classifier dust collector along with the classifier airflow and is collected.
[0022] S54. Store the collected sludge in a storage silo for later use;
[0023] S55. The sludge in the storage bin is transported to the decomposition furnace by a conveying device.
[0024] Optionally, the raw materials selected in step S52 may be fed into a multi-stage cyclone preheater using a conveying device equipped with a metering device.
[0025] To facilitate the implementation of a method for co-processing sludge in cement kilns, this invention provides a system for co-processing sludge in cement kilns, comprising: a drying mill, a cyclone dust collector, a raw material silo, a bag dust collector, a multi-stage cyclone preheater, a decomposition furnace, a rotary kiln, an air classifier, an air classifier dust collector, a storage silo, and a metering and conveying device.
[0026] The flue gas outlet of the multi-stage cyclone preheater is connected to the flue gas inlet of the drying mill; the discharge port of the drying mill is connected in sequence to the cyclone dust collector, raw material silo, multi-stage cyclone preheater, decomposition furnace and rotary kiln.
[0027] The exhaust outlet of the cyclone dust collector is connected to the bag dust collector.
[0028] The exhaust outlet of the multi-stage cyclone preheater is connected to the bag dust collector.
[0029] The ash discharge port of the bag dust collector is connected to the air classifier via a conveyor. The first outlet of the air classifier is connected in sequence to the air classifier dust collector and the storage silo. The discharge port of the storage silo is connected to the decomposition furnace.
[0030] The second outlet of the air classifier is connected to a multi-stage cyclone preheater or to a raw material silo.
[0031] The process involves supplying sludge and raw materials to the drying mill according to a preset amount. The sludge and raw materials then pass through a cyclone dust collector, a raw material silo, a multi-stage cyclone preheater, and a decomposition furnace before entering a rotary kiln for processing.
[0032] The heated flue gas inside the rotary kiln enters the multi-stage cyclone preheater through the decomposition furnace, and the flue gas inside the multi-stage cyclone preheater enters the drying mill or bag dust collector.
[0033] Optionally, the multi-stage cyclone preheater includes: a first-stage cyclone preheater, a second-stage cyclone preheater, a third-stage cyclone preheater, and a fourth-stage cyclone preheater connected in sequence. The exhaust gas outlet of the first-stage cyclone preheater is connected to a drying mill or a bag dust collector, the material outlet of the third-stage cyclone preheater is connected to a decomposition furnace, and the material outlet of the fourth-stage cyclone preheater is connected to a rotary kiln.
[0034] Optionally, an elevator is provided between the raw material silo and the multi-stage cyclone preheater, and the second outlet of the classifier is connected to the feed inlet of the elevator by a conveying device with a metering device.
[0035] Compared with the prior art, the beneficial effects of the present invention are:
[0036] 1. This separation technology is based on the characteristics of raw materials having high density and large particle size, and sludge powder having low density and small particle size, and uses air separation to separate the particles.
[0037] 2. The dust collected by the bag filter is fed into the air classifier. Under the action of the airflow, the raw material powder (containing trace amounts of larger sludge particles) is discharged from the air classifier hopper as coarse powder and sent to the raw material silo via a conveying device or directly into the primary cyclone preheater before entering the kiln. The sludge powder (containing a small amount of fine limestone powder) leaves the air classifier as fine powder and is collected in a separate finished product bag filter. The collected sludge powder is stored in a dried sludge storage silo and then sent to the decomposition furnace for combustion and decomposition via a metering conveyor.
[0038] 3. Metering and conveying equipment is used to accurately control the feeding amount, so as to stabilize the production quality while treating sludge.
[0039] 4. In this invention, sludge with a moisture content of 30%-80% is fed into a drying mill as fuel and auxiliary material for processing. The raw material and dry sludge powder enter the decomposition furnace and rotary kiln, and the dry sludge powder provides reaction fuel for the decomposition furnace and rotary kiln. Attached Figure Description
[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0041] Figure 1 This is a schematic diagram of the system structure for the co-processing of sludge in a cement kiln.
[0042] Figure 2 A schematic diagram of the process structure for a method of co-processing sludge in a cement kiln.
[0043] Figure label:
[0044] 1. Metering feeder;
[0045] 2. Drying mill;
[0046] 3. Cyclone dust collector;
[0047] 4. Raw material storage;
[0048] 5. Bag dust collector;
[0049] 6. Multi-stage cyclone preheater; 61. Single-stage cyclone preheater; 62. Two-stage cyclone preheater; 63. Three-stage cyclone preheater; 64. Four-stage cyclone preheater;
[0050] 7. Decomposition furnace;
[0051] 8. Rotary kiln;
[0052] 9. Air classifier;
[0053] 10. Dust collector for air classifier;
[0054] 11. Storage silos;
[0055] 12. Measuring devices;
[0056] 13. Metering and conveying device. Detailed Implementation
[0057] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.
[0058] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0059] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0060] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0061] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0062] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0063] like Figure 1 and Figure 2 As shown in the figure, an embodiment of the present invention provides a method for co-processing sludge in a cement kiln, comprising the following steps:
[0064] S1. Sludge and raw materials with a moisture content of 30%-80% are conveyed to the drying mill 2. The drying mill 2 processes the sludge and raw materials to obtain a mixture.
[0065] S2. The mixed material is separated from the flue gas by the cyclone dust collector 3. The separated mixed material is stored in the raw material silo 4 for later use, and the flue gas is sent into the bag dust collector 5 for treatment.
[0066] S3. The mixture in the raw material silo 4 is lifted to the multi-stage cyclone preheater 6 for preheating treatment. After preheating treatment, it is transported to the decomposition furnace 7 for decomposition treatment. The exhaust gas outlet of the multi-stage cyclone preheater 6 is connected to the drying mill 2 or the bag dust collector 5.
[0067] S4. The decomposed material is discharged into the rotary kiln 8 for sintering and the product is obtained. The hot flue gas generated by the rotary kiln 8 and the decomposition furnace 7 provides heat to the multi-stage cyclone preheater 6 and the drying mill 2 in sequence.
[0068] The dust collected by bag dust collector S5 is sent to the classifier 9 for separation, separating the sludge from other raw materials. The dry sludge powder separated by the classifier is sent to the decomposition furnace for combustion and decomposition.
[0069] In one embodiment, the first-stage cyclone preheater 61 of the multi-stage cyclone preheater 6 in step S3 is connected to the drying mill 2 or the bag filter 5; the material outlet of the penultimate stage cyclone preheater 6 is connected to the decomposition furnace 7; and the material outlet of the last stage cyclone preheater 6 is connected to the rotary kiln 8. In another embodiment, the multi-stage cyclone preheater 6 in step S3 includes a first-stage cyclone preheater 61, a second-stage cyclone preheater 62, a third-stage cyclone preheater 63, and a fourth-stage cyclone preheater 64. The exhaust outlet of the first-stage cyclone preheater 61 is connected to the drying mill 2 or the bag filter 5. The material outlet of the third-stage cyclone preheater 63 is connected to the decomposition furnace 7, and the material outlet of the fourth-stage cyclone preheater 64 is connected to the rotary kiln 8.
[0070] In one embodiment, in step S3, the multi-stage cyclone preheater 6 is connected to the drying mill 2 or the multi-stage cyclone preheater 6 is connected to the bag dust collector 5 according to preset conditions.
[0071] In one embodiment, the preset condition in step S3 is to preset the start and stop time period of the drying mill 2 according to the peak and valley periods of the mains power.
[0072] When the drying mill 2 is started, the exhaust gas outlet of the multi-stage cyclone preheater 6 is connected to the drying mill 2, and then connected to the bag dust collector 5 through the cyclone dust collector 3; when the drying mill 2 is stopped, the exhaust gas outlet of the multi-stage cyclone preheater 6 is connected to the bag dust collector 5.
[0073] In one embodiment, in step S5, the dust collected by the bag dust collector 5 is sent into the air classifier 9 for sorting, separating the sludge from other raw materials, including the following steps:
[0074] S51. The dust collected by the bag dust collector 5 is sorted using a dust classifier 9;
[0075] S52. The sorted raw materials are sent to the raw material silo 4 or the multi-stage cyclone preheater 6;
[0076] S53. The sludge enters the classifier dust collector along with the classifier airflow of the classifier 9 for collection;
[0077] S54. Store the collected sludge in storage bin 11 for later use;
[0078] S55. The sludge in the storage bin 11 is transported to the decomposition furnace 7 by a conveying device.
[0079] In one embodiment, when the raw material selected in step S52 is fed into the multi-stage cyclone preheater 6, it is transported using a conveying device with a metering device.
[0080] Sludge with a moisture content of 30%–80% is fed into the drying mill 2 via metering feeder 1, and ground together with the raw materials (such as limestone) in the drying mill 2 (the weight of sludge entering the drying mill 2 should not exceed 10% of the total weight of the materials entering the drying mill 2). Hot flue gas introduced by the multi-stage cyclone preheater 6, which is connected to the rotary kiln 8 and the decomposition furnace 7, is fed into the drying mill 2 to dry the sludge and raw materials. The dried sludge and raw materials are collected together by the cyclone dust collector 3 and then sent to the raw material silo 4 for storage. During the drying and grinding process, a portion of the fine sludge powder is directly collected with the dried flue gas in the bag dust collector 5 at the kiln tail.
[0081] The spare material in the raw material silo 4 is fed into the feed inlet of the first-stage cyclone preheater 61 by the elevator. The spare material is separated in the first-stage cyclone preheater 61. The separated raw material enters the second-stage cyclone preheater 62, and then is preheated by the third-stage cyclone preheater 63 and the fourth-stage cyclone preheater 64. The preheated sludge and raw materials are directly fed into the decomposition furnace 7 for decomposition. After decomposition, they enter the rotary kiln 8 for calcination to obtain the finished product (i.e., cement clinker).
[0082] When the primary cyclone preheater 61 preheats the sludge and raw materials, the generated hot flue gas contains a small amount of raw material powder and most of the dry sludge powder. The small amount of raw material powder and most of the dry sludge powder are discharged into the drying mill 2 through the exhaust duct of the primary cyclone preheater 61 along with the flue gas. This allows part of the sludge powder to enter the raw material silo 4 for storage after passing through the drying mill 2, while the other part enters the bag dust collector 5 at the kiln tail for processing along with the flue gas.
[0083] When the drying mill 2 is shut down, a small amount of raw powder and most of the dry sludge powder coming out of the primary cyclone preheater 61 directly enter the bag dust collector 5 at the kiln tail for collection.
[0084] More specifically, the production company presets the operating time of the drying mill 2 according to the peak and off-peak electricity conditions. When the mains power is at its peak, the drying mill 2 stops, and the mixed material stored in the raw material silo 4 is fed to the primary cyclone preheater 61. At the same time, the valve between the primary cyclone preheater 61 and the drying mill 2 is closed, so that the primary cyclone preheater 61 is connected to the bag dust collector 5, and the flue gas from the primary cyclone preheater 61 can only be discharged to the bag dust collector 5 for purification.
[0085] The start and stop times of the drying mill 2 can be set according to the peak and valley times of the mains electricity, so that electricity can be used in a staggered manner and energy costs can be saved.
[0086] The dust collected by the bag filter 5 includes raw material powder and dry sludge powder. Therefore, the bag filter 5 is connected to the air classifier 9, which separates the dry sludge powder and raw material powder from the dust. The dry sludge powder is then collected by the air classifier dust collector 10 and stored in the storage silo 11. It is then sent to the decomposition furnace 7 for combustion and decomposition according to production needs. This avoids the sludge powder from circulating and accumulating between the primary cyclone preheater 61 and the bag filter 5, thus solving the problem of a significant increase in the resistance of the bag filter 5. The raw material powder is sent to the raw material silo 4 or the primary cyclone preheater 61.
[0087] This separation technology utilizes air separation to separate raw materials, which have high density and large particle size, and sludge powder, which has low density and small particle size.
[0088] The dust collected by the bag filter 5 is fed into the air classifier 9. Under the action of the airflow, the raw material powder (containing trace amounts of larger sludge particles) is discharged from the ash hopper of the air classifier 9 as coarse powder and sent to the raw material silo 4 via a conveying device with a metering device 12 or directly into the primary cyclone preheater 61 and then into the kiln. The sludge powder (containing a small amount of fine limestone powder) leaves the air classifier 9 as fine powder and is collected in a separate finished product bag filter 10. The collected sludge powder is stored in the dried sludge storage silo 11 and then sent to the decomposition furnace 7 for combustion and decomposition via a metering conveyor 13.
[0089] Metering and conveying equipment is used to accurately control the feeding amount, so as to achieve stable production quality while treating sludge.
[0090] In this invention, sludge with a moisture content of 30%-80% is fed into the drying mill 2 as fuel and auxiliary material for processing. The raw material and dry sludge powder are fed into the decomposition furnace 7 and the rotary kiln 8, and the dry sludge powder provides reaction fuel for the decomposition furnace 7 and the rotary kiln 8.
[0091] To facilitate the implementation of a method for co-processing sludge in cement kilns, this invention provides a system for co-processing sludge in cement kilns, such as... Figure 1 and Figure 2 As shown, the system includes: a drying mill 2, a cyclone dust collector 3, a raw material silo 4, a bag dust collector 5, a multi-stage cyclone preheater 6, a decomposition furnace 7, a rotary kiln 8, an air classifier 9, an air classifier dust collector 10, a storage silo 11, and a metering and conveying device 13.
[0092] The flue gas outlet of the multi-stage cyclone preheater 6 is connected to the flue gas inlet of the drying mill 2; the discharge port of the drying mill 2 is connected in sequence to the cyclone dust collector 3, the raw material silo 4, the multi-stage cyclone preheater 6, the decomposition furnace 7 and the rotary kiln 8.
[0093] The exhaust outlet of the cyclone dust collector 3 is connected to the bag dust collector 5; the exhaust outlet of the multi-stage cyclone preheater 6 is connected to the bag dust collector 5.
[0094] The ash discharge port of the bag dust collector 5 is connected to the classifier 9 via a conveyor. The first outlet of the classifier 9 is connected in sequence to the classifier dust collector 10 and the storage silo 11. The discharge port of the storage silo 11 is connected to the decomposition furnace 7 via a metering and conveying device.
[0095] The second outlet of the air classifier 9 is connected to the multi-stage cyclone preheater 6 or to the raw material silo 4;
[0096] The sludge and raw materials are supplied to the drying mill 2 according to the preset amount. The sludge and raw materials pass through the cyclone dust collector 3, raw material silo 4, multi-stage cyclone preheater 6, decomposition furnace 7 and then enter the rotary kiln 8 for processing.
[0097] The flue gas carrying heat in the rotary kiln 8 enters the multi-stage cyclone preheater 6 through the decomposition furnace 7, and the flue gas in the multi-stage cyclone preheater 6 enters the drying mill 2 or the bag dust collector 5.
[0098] In one embodiment, the multi-stage cyclone preheater 6 includes: a primary cyclone preheater 61, a secondary cyclone preheater 62, a tertiary cyclone preheater 63, and a quaternary cyclone preheater 64 connected in sequence. The exhaust outlet of the primary cyclone preheater 61 is connected to the drying mill 2 or the bag dust collector 5. The material outlet of the tertiary cyclone preheater 63 is connected to the decomposition furnace 7. The material outlet of the quaternary cyclone preheater 64 is connected to the rotary kiln 8.
[0099] It should be noted that in actual production, the number of preheater stages in the multi-stage cyclone preheater 6 can be increased or decreased according to actual needs. The exhaust outlet of the first cyclone preheater is connected to the drying mill 2 or the bag dust collector 5. The material outlet of the penultimate cyclone preheater is connected to the decomposition furnace 7, and the material outlet of the last cyclone preheater is connected to the rotary kiln 8.
[0100] In one embodiment, an elevator is provided between the raw material silo 4 and the multi-stage cyclone preheater 6, and the second outlet of the classifier 9 is connected to the feed inlet of the elevator by a conveying device with a metering device 12.
[0101] Sludge and raw materials with a moisture content of 30%–80% are fed into the drying mill 2 via a metering feeder 1, where they are ground. During the grinding process, hot flue gas is introduced into the raw material drying mill 2 by the rotary kiln 8 and the decomposition furnace 7 via the multi-stage cyclone preheater 6 to dry the sludge and raw materials. The dried sludge and raw materials are collected together by the cyclone dust collector 3 and then sent to the raw material silo 4 for storage. During the drying and grinding process, a portion of the fine sludge powder is directly collected with the dried flue gas in the bag dust collector 5 at the kiln tail.
[0102] The spare material in the raw material silo 4 is fed into the feed inlet of the first-stage cyclone preheater 61 by the elevator. The spare material is separated in the first-stage cyclone preheater 61. The separated raw material is collected in the second-stage cyclone preheater 62. The preheated sludge and raw materials are directly fed into the decomposition furnace 7 for decomposition treatment. After decomposition, they are fed into the rotary kiln 8 for calcination to obtain the finished product (i.e. cement clinker).
[0103] In another embodiment, the spare material is separated in the first-stage cyclone preheater 61, and the separated raw material is collected in the second-stage cyclone preheater 62 for preheating, and then preheated through the third-stage cyclone preheater 63 and the fourth-stage cyclone preheater 64 (the specific number of stages of the multi-stage cyclone preheater 6 can be increased or decreased according to the needs), so that the spare material reaches a higher temperature after passing through the multi-stage cyclone preheater 6.
[0104] When the primary cyclone preheater 61 preheats the sludge and raw materials, the generated hot flue gas contains a small amount of raw material powder and most of the dry sludge powder. The small amount of raw material powder and most of the dry sludge powder are discharged into the drying mill 2 and the bag dust collector 5 at the kiln tail through the exhaust duct of the primary cyclone preheater 61 with the flue gas. Part of the sludge powder enters the raw material silo 4 for storage after passing through the drying mill 2, and the other part enters the bag dust collector 5 at the kiln tail for treatment with the flue gas.
[0105] When the drying mill 2 is shut down, a small amount of raw powder and most of the dry sludge powder coming out of the primary cyclone preheater 61 directly enter the bag dust collector 5 at the kiln tail for collection.
[0106] More specifically, the production company presets the operating time of the drying mill 2 according to the peak and off-peak electricity conditions. When the mains power is at its peak, the drying mill 2 stops, and the spare materials stored in the raw material silo 4 are supplied to the primary cyclone preheater 61. At the same time, the valve between the primary cyclone preheater 61 and the drying mill 2 is closed, so that the primary cyclone preheater 61 is connected to the bag dust collector 5, and the flue gas from the primary cyclone preheater 61 can only be discharged to the bag dust collector 5.
[0107] The start and stop times of the drying mill 2 can be set according to the peak and valley times of the mains electricity, so that electricity can be used in a staggered manner and energy costs can be saved.
[0108] The dust collected by the bag filter 5 includes raw material powder and dry sludge powder. Therefore, the bag filter 5 is connected to the air classifier 9, which separates the dry sludge powder and raw material powder from the dust. The dry sludge powder is then collected by the air classifier dust collector 10 and stored in the storage silo 11. It is then sent to the decomposition furnace 7 for combustion and decomposition according to production needs. This avoids the sludge powder from circulating and accumulating between the primary cyclone preheater 61 and the bag filter 5, thus solving the problem of a significant increase in the resistance of the bag filter 5. The raw material powder is sent to the raw material silo 4 or the primary cyclone preheater 61.
[0109] The following explanation will be based on the existing rotary kiln's daily clinker production as an example.
[0110] Using the above system for co-processing sludge, the existing rotary kiln 8 has a daily clinker production of 2,500 tons, which translates to approximately 3,600 tons of raw material per day, or about 150 tons per hour. The dust collection rate of the primary cyclone preheater 61 is approximately 90%-95%. Assuming 90%, the raw material powder in the flue gas is approximately 15 tons. Based on a sludge usage of 240 tons per day with a 60% moisture content, this equates to approximately 10 tons per hour, or about 4 tons after drying. Therefore, the bag filter 5 at the kiln tail collects approximately 19 tons of ash powder per hour, of which approximately 4 tons are dry sludge powder.
[0111] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. The method for co-processing sludge in a cement kiln according to claim 1, characterized in that, Includes the following steps: S1. Sludge and raw materials with a moisture content of 30%-80% are conveyed to the drying mill, which grinds and dries the sludge and raw materials to obtain a mixture. S2. The mixed materials are separated from the flue gas by a cyclone dust collector. The separated mixed materials are stored in the raw material silo for later use, and the flue gas is sent into a bag dust collector for treatment. S3. The mixture in the raw material silo is lifted to the multi-stage cyclone preheater for preheating. After preheating, it is transported to the decomposition furnace for decomposition. The exhaust gas outlet of the multi-stage cyclone preheater is connected to the drying mill or bag dust collector. S4. The decomposed material is discharged into a rotary kiln for sintering and the product is obtained. The hot flue gas generated by the rotary kiln and the decomposition furnace provides heat to the multi-stage cyclone preheater and the drying mill in sequence. S5. The dust collected by the bag dust collector is sent to the air classifier for separation, separating the sludge from other raw materials. The dry sludge powder separated by the air classifier is sent to the decomposition furnace for combustion and decomposition.
2. The method for co-processing sludge in a cement kiln according to claim 1, characterized in that, In step S3, the first-stage cyclone preheater of the multi-stage cyclone preheater is connected to a drying mill or a bag dust collector, the material outlet of the penultimate stage cyclone preheater is connected to a decomposition furnace, and the material outlet of the last stage cyclone preheater is connected to a rotary kiln.
3. The method for co-processing sludge in a cement kiln according to claim 1 or 2, characterized in that, In step S3, the multi-stage cyclone preheater includes a first-stage cyclone preheater, a second-stage cyclone preheater, a third-stage cyclone preheater, and a fourth-stage cyclone preheater connected in sequence. The exhaust gas outlet of the first-stage cyclone preheater is connected to a drying mill or a bag dust collector, the material outlet of the third-stage cyclone preheater is connected to a decomposition furnace, and the material outlet of the fourth-stage cyclone preheater is connected to a rotary kiln.
4. The method for co-processing sludge in a cement kiln according to claim 1 or 2, characterized in that, In step S3, the multi-stage cyclone preheater is connected to the drying mill or the multi-stage cyclone preheater is connected to the bag dust collector according to preset conditions.
5. The method for co-processing sludge in a cement kiln according to claim 4, characterized in that, The preset condition in step S3 is to preset the start-up and shutdown time periods of the drying mill according to the peak and valley periods of the mains power. When the drying mill starts, the exhaust outlet of the multi-stage cyclone preheater is connected to the drying mill, and the flue gas from the drying mill is connected to the bag dust collector after passing through the cyclone dust collector; when the drying mill is stopped, the exhaust outlet of the multi-stage cyclone preheater is connected to the bag dust collector.
6. The method for co-processing sludge in a cement kiln according to claim 1, characterized in that, In step S5, the dust collected by the bag filter is sent to the air classifier for separation, separating the sludge from other raw materials, including the following steps: S51. Use a classifier to separate the dust collected by the bag dust collector; S52. The sorted raw materials are sent to the raw material silo or multi-stage cyclone preheater; S53. The sludge enters the classifier dust collector along with the classifier airflow and is collected. S54. Store the collected sludge in a storage silo for later use; S55. The sludge in the storage bin is transported to the decomposition furnace by a conveying device.
7. The method for co-processing sludge in a cement kiln according to claim 1, characterized in that, The raw materials selected in step S52 are fed into the multi-stage cyclone preheater using a conveying device equipped with a metering device.
8. The system for the method of co-processing sludge in a cement kiln according to any one of claims 1-7, characterized in that, include: Drying mill, cyclone dust collector, raw material silo, bag dust collector, multi-stage cyclone preheater, decomposition furnace, rotary kiln, air classifier, air classifier dust collector, storage silo and metering conveying device; The flue gas outlet of the multi-stage cyclone preheater is connected to the flue gas inlet of the drying mill; the discharge port of the drying mill is connected in sequence to the cyclone dust collector, raw material silo, multi-stage cyclone preheater, decomposition furnace and rotary kiln. The exhaust outlet of the cyclone dust collector is connected to the bag dust collector; the exhaust outlet of the multi-stage cyclone preheater is connected to the bag dust collector. The bag dust collector is connected to the air classifier, the first outlet of the air classifier is connected in sequence to the air classifier dust collector and the storage silo, and the outlet of the storage silo is connected to the decomposition furnace. The second outlet of the air classifier is connected to a multi-stage cyclone preheater or to a raw material silo. The process involves supplying sludge and raw materials to the drying mill according to a preset amount. The sludge and raw materials then pass through a cyclone dust collector, a raw material silo, a multi-stage cyclone preheater, and a decomposition furnace before entering a rotary kiln for processing. The heated flue gas inside the rotary kiln enters the multi-stage cyclone preheater through the decomposition furnace, and the flue gas inside the multi-stage cyclone preheater enters the drying mill or bag dust collector.
9. The system for co-processing sludge in a cement kiln according to claim 1, characterized in that, The multi-stage cyclone preheater includes: a first-stage cyclone preheater, a second-stage cyclone preheater, a third-stage cyclone preheater, and a fourth-stage cyclone preheater connected in sequence. The exhaust gas outlet of the first-stage cyclone preheater is connected to a drying mill or a bag dust collector. The material outlet of the third-stage cyclone preheater is connected to a decomposition furnace. The material outlet of the fourth-stage cyclone preheater is connected to a rotary kiln.
10. The system for co-processing sludge in a cement kiln according to claim 1, characterized in that, An elevator is installed between the raw material silo and the multi-stage cyclone preheater. The second outlet of the classifier is connected to the feed inlet of the elevator via a conveying device equipped with a metering device.