System and method for rapidly preparing sludge-based derived fuel by using waste heat of cement kiln

Abstract

The invention belongs to the technical field of solid waste recycling and energy conservation and emission reduction in the cement industry, and particularly relates to a system and method for rapidly preparing sludge-based derived fuel by using waste heat of a cement kiln. Comprising a feeding unit, a sludge drying unit, a heat source supply unit, a discharging unit and a tail gas treatment unit, wherein the heat source supply unit introduces 180-220 DEG C cement kiln waste gas into a drying machine through a lateral gas inlet; the bag-type dust collector is used for receiving a drying product discharged from the top of the drying tower, and the mixing tank is arranged on a pipeline of a discharge hole of the bag-type dust collector; the tail gas treatment unit is used for treating gas discharged by the bag-type dust collector; wherein the dried sludge output by the mixing tank is pneumatically conveyed into the cement kiln decomposing furnace. The cement kiln waste gas of the cement kiln waste heat power generation system is recycled, the dewatered sludge is treated to obtain the dried sludge, the dried sludge can serve as sludge-based derived fuel to be introduced into the cement kiln decomposing furnace to serve as fuel, the problem that municipal sludge is difficult to treat is solved, and solid waste recycling is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste resource utilization and energy conservation and emission reduction in the cement industry, and specifically relates to a system and method for rapidly preparing sludge-based derivative fuel by utilizing waste heat from cement kilns. Background Art

[0002] With the continuous acceleration of my country's urbanization process and the extensive construction and upgrading of sewage treatment facilities, the generation of municipal sludge (including some industrial sludge) has shown explosive growth. Its safe, efficient and resource-based disposal has become a major environmental challenge that needs to be addressed urgently. In order to reduce the difficulty of sludge disposal and improve its resource utilization value (especially as a fuel), sludge drying is a key pretreatment step. However, traditional sludge drying technologies (such as direct hot air drying, indirect steam drying, solar drying, etc.) generally face core bottlenecks:

[0003] (1) Huge energy consumption and high cost: Evaporating water requires a large amount of heat energy, which usually accounts for more than 60% of the total energy consumption of the entire disposal process. Relying on fossil fuels (natural gas, coal) or high-quality steam as a heat source makes the drying cost high, which seriously restricts the economic feasibility of sludge resource utilization.

[0004] (2) Long drying cycle and low efficiency: Conventional thermal drying processes (such as belt drying and paddle drying) often take tens of minutes or even longer to deeply dehydrate the sludge to a low moisture content suitable for fuel utilization (such as <30%). The equipment occupies a large area and the processing capacity is limited.

[0005] (3) Secondary pollution and safety risks: The drying process may produce tail gas containing odor, dust, and volatile organic compounds (VOCs). If not handled properly, it will cause secondary air pollution. At the same time, when the sludge is within a certain temperature range during the drying process (especially during the slow heating process), there are safety hazards such as dust explosion and spontaneous combustion.

[0006] (4) Poor heat source matching: Finding a stable, sufficient and economical low-grade heat source (180-220°C) is the key to reducing drying costs, but such heat sources are difficult to obtain or are not used efficiently in most scenarios.

[0007] On the other hand, the cement industry is a typical high energy consumption and high emission industry. During the production process of the new dry process cement kiln, especially after the preheater and the waste heat boiler (SP boiler) at the kiln tail, a large amount of low and medium temperature waste gas with a temperature in the range of 180-250°C will be discharged. The grade of this part of waste heat is relatively low, and the efficiency of direct power generation (waste heat power generation) is limited (low Carnot cycle efficiency). After power generation, the temperature of the waste gas is usually as high as 180-200°C, and the heat contained is considerable but often not fully utilized, usually directly discharged into the atmosphere or only used for preliminary drying of raw materials, resulting in waste of energy. The cement kiln itself is a good high-temperature incinerator and has great potential for co-processing solid waste.

[0008] Therefore, using the excess low-grade waste heat of the cement kiln (especially the 180-220°C low-temperature waste gas still with utilization value after waste heat power generation) for efficient sludge drying and directly preparing into derived fuel (SRF / RDF) suitable for burning in the cement kiln is theoretically an extremely attractive technical path of "waste control and turning waste into treasure". In recent years, although some research and practice attempts have been made to use cement kiln waste gas for sludge drying, the existing technology still exposes a series of key problems in actual application:

[0009] (1) Low heat utilization efficiency: The contact mode of waste gas and sludge (such as traditional rotary kiln, static composting) is not reasonable, the heat and mass transfer efficiency is poor, the sensible heat in the waste gas cannot be fully absorbed and utilized by the sludge, and a large amount of heat is wasted with the tail gas, resulting in still high unit sludge drying energy consumption.

[0010] (2) Uneven drying and large quality fluctuation: Improper drying process control leads to uneven heating of the sludge, partial areas are over-dried (easy to pulverize, dust, spontaneous combustion), and partial areas still contain too much water (affecting the calorific value and subsequent combustion stability), making it difficult to stably reach the target calorific value (such as >2000kcal / kg) requirement, and unable to meet the standard of stable alternative fuel for the cement kiln.

[0011] (3) Poor coupling of process and kiln system: The drying system is often independent of the main process design of the cement kiln, and the influence of the fluctuation of waste gas parameters (flow, temperature, dust content) on the drying effect is not fully considered, and there is also a lack of intelligent linkage control with the kiln system operation, resulting in unstable system operation, affecting the cement production and drying effect.

[0012] (4) Insufficient secondary pollution control: The tail gas generated during the drying process contains high humidity, odor, dust and trace pollutants, and lacks efficient and low energy consumption purification treatment schemes, which easily causes new environmental problems and may also affect the standard discharge of the cement kiln tail gas.

[0013] (5) "fueling" target is not clear or incomplete: some technologies only focus on drying reduction, and do not stabilize and efficiently produce high-quality SRF / RDF from drying products that can be directly used for cement kiln combustion (such as insufficient control of key fuel indicators such as particle size, calorific value, chlorine and sulfur content).

[0014] In summary, developing an integrated process and method capable of utilizing the low-temperature waste gas after waste heat power generation of a cement kiln to rapidly realize deep dewatering of sludge and synchronous preparation of sludge-based derived fuel (SRF / RDF) has extremely important practical significance and application value for solving the current sludge disposal problem, tapping the energy saving and emission reduction potential of the cement industry, and realizing the recycling of solid waste resources. SUMMARY

[0015] In view of the above shortcomings of the prior art, the present application aims to provide a system and method for rapidly preparing sludge-based derived fuel using cement kiln waste heat, which reuses the cement kiln waste gas of the cement kiln waste heat power generation system to obtain dried sludge by treating dewatered sludge, and the dried sludge can be introduced into the cement kiln decomposition furnace as fuel, thus solving the problem of municipal sludge treatment and realizing the recycling of solid waste resources.

[0016] To achieve the above object and other related objects, the present application provides a system for rapidly preparing sludge-based derived fuel using cement kiln waste heat, comprising:

[0017] A feeding unit, which comprises a sludge storage bin;

[0018] A sludge drying unit, which comprises an integrated drying machine and a drying tower, the drying machine is of horizontal paddle structure, one end of which is connected to the sludge storage bin through a feeding pipe, and the other end is directly connected to the bottom of the drying tower through a discharging pipe, and a tangential air inlet is arranged near the feeding pipe of the drying machine;

[0019] A heat source supply unit, which supplies 180-220℃ cement kiln waste gas to the drying machine through a lateral air inlet;

[0020] A discharging unit, which comprises a bag filter and a mixing tank connected in series, the bag filter receives the dried product discharged from the top of the drying tower, and the mixing tank is arranged on the discharging pipe line of the bag filter;

[0021] A tail gas treatment unit, which treats the gas discharged from the bag filter;

[0022] The dried sludge output from the mixing tank is transported to the cement kiln decomposition furnace by air pressure.

[0023] In one embodiment of the present application, the drying tower is a cyclone airflow drying tower, the inside of the drying tower is vertically arranged with three layers of annular guide plates, the adjacent guide plates are opposite in rotation direction, and a rotating breaking shaft is arranged, and the rotating breaking shaft is uniformly provided with sawtooth-shaped breaking blades.

[0024] In one embodiment of the present application, the discharging unit further comprises a metering feeder arranged on the discharging port pipeline of the bag-type dust collector.

[0025] In one embodiment of the present application, the discharging unit further comprises a compressed air tank and a pressure adjusting device, the compressed air tank is communicated with the mixing tank through a pipeline, and the drying sludge in the mixing tank is transported into the cement kiln decomposition furnace through the air pressure difference.

[0026] In one embodiment of the present application, the heat source supply unit comprises an induced draft fan, a three-way air inlet pipeline and a proportional adjusting valve, the outlet pipeline of the fan is communicated with the tangential air inlet of the drying machine, the first path of the three-way air inlet pipeline is connected with the cement kiln waste gas outlet of the cement kiln waste heat power generation system, the second path is connected with the outlet pipeline of the tail gas treatment unit, the third path is connected with the external atmosphere, and the proportional adjusting valve is used to control the mixing ratio of the cement kiln waste gas and the dry waste gas obtained from the tail gas treatment unit.

[0027] In one embodiment of the present application, the tail gas treatment unit comprises a condensation heat exchanger, a catalytic oxidation reactor, a biological deodorizer and an exhaust fan arranged in sequence, and the condensation dehumidifier is arranged on the gas outlet pipeline of the bag-type dust collector.

[0028] In one embodiment of the present application, the cooling medium outlet of the condensation heat exchanger is communicated with the sludge storage bin through a pipeline, and is used to preheat the feeding sludge.

[0029] In one embodiment of the present application, a temperature and humidity sensor is arranged on the outlet pipeline at the top of the drying tower, and is used to measure the temperature and humidity of the drying product at the discharging port of the drying tower.

[0030] In one embodiment of the present application, a near-infrared online detector and an X-ray fluorescence spectrometer are arranged on the discharging port pipeline of the bag-type dust collector, and are used to monitor the calorific value and chlorine and sulfur content of the drying sludge in real time.

[0031] To achieve the above object and other related objects, the present application provides a method for rapidly preparing sludge-based derived fuel by using cement kiln waste heat, which comprises the following steps:

[0032] The water-containing sludge with a water content of ≥60% is input into the drying machine, and is contacted with 180-220°C cement kiln waste gas to perform pre-drying; after the pre-drying, the sludge is further dehydrated to a water content of <10% in the drying tower to obtain a drying product.

[0033] The dried product is separated into dry sludge and dry waste gas through a bag dust collector. The dry sludge is pneumatically conveyed to the cement kiln decomposition furnace; the treated dry waste gas is passed into the dryer for recycling;

[0034] According to the temperature and humidity at the drying tower outlet, the ratio of cement kiln exhaust gas to recycled dry exhaust gas is dynamically adjusted to control temperature fluctuation to ≤±5℃; the calorific value of dry sludge is monitored, and the inlet temperature of the dryer and the sludge residence time are adjusted according to the calorific value feedback.

[0035] The beneficial technical effects of the present invention include at least:

[0036] The present invention discloses a system for rapidly preparing sludge-based derived fuel using waste heat from a cement kiln. The system integrates a dryer and a drying tower in a compact "horizontal dryer + vertical drying tower" layout, forming a "tangential air inlet - axial discharge - guide swirl" transmission path. Cement kiln exhaust gas enters the dryer tangentially at a speed of 18 m / s, forming a primary swirl field. Pre-dried sludge is mixed with the exhaust gas and then enters the drying tower axially. Three layers of guide plates (with an opening rate of 40%) with opposite rotation directions in the drying tower create a strong turbulent flow, further drying the sludge. The sludge has a moisture content of less than 10%, a drying uniformity of more than 95%, and a stable calorific value that meets standards.

[0037] This invention innovatively develops a three-stage utilization model for low-grade, 180-220°C, waste gas from cement kilns: the first stage is used for pre-drying in the dryer, the second stage is deep dehydration in the drying tower, and the third stage uses condensation heat exchange to recover waste heat for feed preheating. This reduces drying energy consumption by over 50% compared to traditional thermal drying, achieving truly "zero fossil fuel consumption" sludge drying. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 This is a system diagram for rapidly preparing sludge-based derived fuel using waste heat from a cement kiln in one embodiment of the present invention.

[0040] Among them: 1-sludge storage bin; 2-drying machine 2; 3-drying tower; 4-bag dust collector; 5-mixing tank; 6-compressed air tank; 7-condensation heat exchanger; 8-catalytic oxidation reactor; 9-biological deodorizer; 10-exhaust fan; 11-induced draft fan. DETAILED DESCRIPTION

[0041] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0042] It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0043] See also Figure 1 As shown, in order to achieve the above-mentioned purpose and other related purposes, the present invention proposes a system for rapidly preparing sludge-based derivative fuel by utilizing waste heat from a cement kiln, comprising a feeding unit, a sludge drying unit, a heat source supply unit, a discharging unit and an exhaust gas treatment unit, wherein the feeding unit comprises a sludge storage bin 1; the sludge drying unit comprises an integrated drying machine 2 and a drying tower 3, the drying machine 2 is a horizontal paddle structure, one end of which has a feed port pipe connected to the sludge storage bin 1, and the other end of which has a discharge port directly connected to the feed port at the bottom of the drying tower 3. A tangential air inlet is provided near the feed port of the dryer 2; the heat source supply unit introduces 180-220°C cement kiln exhaust gas into the dryer 2 through the lateral air inlet; the discharge unit includes a connected bag dust collector 4 and a mixing tank 5, the bag dust collector 4 receives the dried product discharged from the top of the drying tower 3, and the mixing tank 5 is arranged on the discharge port pipeline of the bag dust collector 4; the tail gas treatment unit processes the gas discharged from the bag dust collector 4; among them, the dried sludge output from the mixing tank 5 is pneumatically transported to the cement kiln decomposition furnace.

[0044] It should be noted that traditional sludge disposal methods (such as landfill and incineration) have the problems of large land occupation, high risk of secondary pollution or the need for additional fuel, and conventional sludge drying technology has high energy consumption and long cycle, which restricts its resource application as fuel. The present invention overcomes the above-mentioned defects and provides an economical, efficient and environmentally friendly new way to treat and fuel sludge. Its core lies in the innovative coupling of the operating characteristics of cement kilns, directly utilizing the low-temperature exhaust gas (such as 180-220°C exhaust gas) after the waste heat of the kiln system is used to generate electricity as a heat source for sludge drying, and through a specific rapid drying process (such as cyclone graded drying, etc.), the high-moisture content sludge is deeply dehydrated to the target low calorific value (such as >2000kcal / kg) in a very short time, and the sludge is simultaneously harmless, reduced and stably fueled. The present invention not only significantly reduces the energy consumption and cost of sludge drying, avoids fossil fuel consumption, and improves the utilization efficiency of waste heat from cement kilns, but also provides the cement kiln itself with high-quality biomass-derived fuel that can directly replace part of the fossil fuels, thus achieving the dual goals of "treating waste with waste" and "turning waste into treasure."

[0045] In one embodiment of the present invention, the drying tower 3 is a cyclone airflow drying tower 3, and three layers of annular guide plates are arranged vertically inside the drying tower 3, and the rotation directions of adjacent guide plates are opposite. A rotating crushing shaft is provided, and each rotating crushing shaft is evenly provided with serrated crushing blades.

[0046] It should be noted that the opening rate of each guide plate is 30-50%, the inclination angle is 15-45 degrees, and the rotation speed of each rotating crushing shaft is 200-800 rpm.

[0047] It can be understood that high-humidity sludge (moisture content ≥ 60%) enters the horizontal paddle dryer 2 through the feed port, and 180-220℃ cement kiln exhaust gas is tangentially introduced into the dryer 2 at a speed of 15-20m / s, forming a primary cyclone field. The mechanical stirring of the blades and the turbulence of the exhaust gas work together to initially crush and preheat the sludge. After pre-drying, the moisture content of the sludge can be reduced to 40-50%, and the temperature rises to 70-90℃; the three layers of annular guide plates in the drying tower 3 convert its axial air intake into a rotating upward airflow, and the adjacent guide plates rotate in opposite directions, forming staggered turbulence and increasing the turbulence intensity. The guide plate opening rate of 30-50% balances the air flow distribution and pressure drop. The rotating crushing shaft can crush the falling sludge clumps in real time, and the rotating crushing shaft and the guide plates work together to extend the particle residence path (the actual contact time is extended by 3-5 times). Therefore, under the joint action of the integrated dryer 2 and the drying tower 3, the moisture content of the sludge is reduced to <10% within 10-300 seconds, and dried sludge with a low calorific value of >2000kcal / kg is obtained.

[0048] In one embodiment of the present invention, the discharging unit further includes a metering feeder, which is arranged on the discharge port pipeline of the bag filter 4 .

[0049] Furthermore, a neutralization adding device may be provided on the outlet pipeline of the metering feeder. When the chlorine content is detected to be greater than 0.8% or the sulfur content is greater than 1.0%, calcium oxide or sodium bicarbonate may be added to the dry sludge at the outlet of the metering feeder through the neutralization adding device for neutralization.

[0050] In one embodiment of the present invention, the discharging unit further includes a compressed air tank 6 and a pressure regulating device. The compressed air tank 6 is connected to the mixing tank 5 through a pipeline, and the dried sludge in the mixing tank 5 is transported to the cement kiln decomposition furnace through the air pressure difference.

[0051] In one embodiment of the present invention, the heat source supply unit includes an induced draft fan 11, a three-way air intake pipeline and a proportional control valve. The outlet pipe of the fan is connected to the tangential air inlet of the dryer 2. The first line of the three-way air intake pipeline is connected to the cement kiln exhaust gas outlet of the cement kiln waste heat power generation system, the second line is connected to the outlet pipeline of the exhaust gas treatment unit, and the third line is connected to the outside atmosphere. The proportional control valve is used to control the mixing ratio of the cement kiln exhaust gas introduced through the two-way air intake pipeline and the dry exhaust gas obtained by the exhaust gas treatment unit.

[0052] It should be noted that the second outlet pipeline connected to the exhaust gas treatment unit is used to recycle the dry waste gas obtained through the exhaust gas treatment unit, which can adjust the temperature and humidity of the dried product at the outlet of the drying tower 3. The third pipeline connected to the outside atmosphere can adjust the temperature of the waste gas entering the drying tower 3.

[0053] In one embodiment of the present invention, the exhaust gas treatment unit includes a condensing heat exchanger 7, a catalytic oxidation reactor 8, a biological deodorizer 9 and an exhaust fan 10 arranged in series, and the condensing dehumidifier is arranged on the outlet pipeline of the bag dust collector 4.

[0054] It should be noted that the bag filter 4 separates the dust-removed dry exhaust gas, which is then purified in sequence through condensation dehumidification, low-temperature catalytic oxidation, and biological deodorization, and can only be discharged after meeting the standards.

[0055] In one embodiment of the present invention, the cooling medium outlet of the condensing heat exchanger 7 is connected to the sludge storage bin through a pipeline for preheating the feed sludge.

[0056] It should be noted that the condensing heat exchanger 7 uses 10-15°C cold water as a refrigerant to recover 40-60% of the latent heat in the tail gas. The recovered condensation heat is used to preheat the feed sludge, raising the initial sludge temperature to 50-70°C.

[0057] In one embodiment of the present invention, a temperature and humidity sensor is provided on the outlet pipeline at the top of the drying tower 3 for measuring the temperature and humidity of the dried product at the outlet of the drying tower 3 .

[0058] In one embodiment of the present invention, a near-infrared online detector and an X-ray fluorescence spectrometer are provided on the discharge port pipeline of the bag filter 4 to monitor the calorific value and chlorine and sulfur content of the dried sludge in real time.

[0059] It should be noted that the exhaust gas inlet temperature (±10° C.) and the sludge residence time (±10%) of the dryer 2 are feedback-regulated by the calorific value of the dried sludge.

[0060] To achieve the above and other related objectives, the present invention provides a method for rapidly preparing sludge-based derived fuel using waste heat from a cement kiln, comprising the following steps:

[0061] The sludge with a moisture content of ≥60% is passed into the dryer 2 and contacted with the 180-220°C cement kiln exhaust gas for pre-drying. After pre-drying, the sludge enters the drying tower 3 for further dehydration to a moisture content of <10% to obtain a dried product.

[0062] The dried product is separated into dry sludge and dry exhaust gas through the bag filter 4. The dry sludge is pneumatically transported to the cement kiln decomposition furnace; the treated dry exhaust gas is passed into the dryer 2 for recycling;

[0063] According to the outlet temperature and humidity of the drying tower 3, the ratio of cement kiln exhaust gas to circulating dry exhaust gas is dynamically adjusted to control the temperature fluctuation to ≤±5℃; the calorific value of the dry sludge is monitored, and the inlet temperature and sludge residence time of the dryer 2 are adjusted according to the calorific value feedback.

[0064] Furthermore, by monitoring the chlorine and sulfur content of dry sludge, the amount of dry sludge input can be adjusted according to the chlorine and sulfur content. Because high alkali, sulfur and chlorine content will mainly affect the crusting of cement production.

[0065] Furthermore, the system of the present invention for rapidly preparing sludge-based derivative fuel using waste heat from a cement kiln is interconnected with the cement kiln DCS system to obtain real-time exhaust gas parameters from the kiln tail and automatically adjust the operating status of the drying tower 3, including: when the exhaust gas temperature at the kiln tail drops by more than 15°C, the feed rate of the water-containing sludge to the dryer 2 is simultaneously reduced by 10-20%; when the exhaust gas flow fluctuation is more than 20%, the standby thermal storage heat exchanger is started to compensate for the heat energy.

[0066] The system and method of the present invention for rapidly preparing sludge-based derivative fuel using waste heat from cement kilns were used to treat municipal sludge and industrial sludge, respectively, to obtain the following two examples:

[0067] Example 1: Municipal sludge drying and fuel conversion (daily processing of 100 tons),

[0068] Raw materials and heat source: The sludge is municipal dewatered sludge (water content 82%), with a daily processing capacity of 100 tons, chlorine content 0.5%, and sulfur content 0.6%. The heat source is the exhaust gas after the SP boiler of the cement kiln (temperature 195℃±5℃, flow rate 25,000Nm3 / h)

[0069] The core equipment and process parameters are as follows: It should be noted that the "cyclone graded drying" in the table mainly describes the relevant process parameters of the drying tower 3 (cyclone drying tower) and the dryer 2 (paddle dryer).

[0070]

[0071]

[0072] Operational results: Drying energy consumption is only 0.08kWh / kg water (conventional process > 0.25kWh / kg water); standard deviation of calorific value of dried sludge is <50kcal / kg (uniformity > 97%); annual CO2 emission reduction is ≈12,000 tons (replacing fossil fuels)

[0073] Example 2: Co-processing of industrial sludge (high chlorine conditions),

[0074] Raw materials and special challenges: The sludge is mixed sludge from a printing and dyeing factory (78% moisture content, 1.2% chlorine content, and 0.9% sulfur content). The difficulty lies in the excessive chlorine content, which is prone to corroding the kiln and requires precise neutralization.

[0075] The key links are adjusted as follows:

[0076]

[0077] Operational results: The moisture content of the dried sludge is 9.5%, the calorific value is 2050kcal / kg, the chlorine content is 0.25%, and the sulfur content is 0.35%; the temperature deviation of the drying tower 3 is less than 8°C under fluctuating kiln conditions (no safety shutdown is triggered); the sludge treatment cost is 40% lower than incineration, and the fuel replacement income is ≈300 yuan / ton of dried sludge.

[0078] In summary, the present invention is highly effective in treating both municipal and industrial sludge. The resulting dry sludge produces high-quality SRF / RDF with uniform particle size, stable calorific value, and controlled harmful substances. This can be directly fed into the kiln, replacing 20%-30% of fossil fuels and reducing the carbon footprint of cement production. The closed-loop exhaust gas purification system of the present invention completely eliminates odor, dust, and VOC pollution. Pathogens and organic matter in the sludge are inactivated / solidified at high drying temperatures, rendering them harmless.

[0079] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

[0080] In the description herein, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of the embodiments of the present invention. However, those skilled in the art will recognize that embodiments of the present invention may be practiced without one or more of the specific details or with other devices, systems, assemblies, methods, components, materials, parts, etc. In other cases, well-known structures, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of the embodiments of the present invention.

[0081] Reference throughout this specification to "one embodiment," "an embodiment," or "a specific embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention, and not necessarily in all embodiments. Thus, various appearances of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment of the invention may be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the invention described and illustrated herein are possible in light of the teachings herein and are considered part of the spirit and scope of the invention.

[0082] It should also be understood that one or more of the elements shown in the figures may also be implemented in a more separate or more integrated manner, or even removed because they are inoperable in certain circumstances or provided because they may be useful depending on the application.

[0083] In addition, unless otherwise expressly indicated, any marking arrows in the drawings should be regarded as illustrative only and not limiting. Furthermore, unless otherwise indicated, the term "or" as used herein is generally intended to mean "and / or." Where a term is unclear in providing separation or combination capabilities, the combination of components or steps will also be considered as indicated.

[0084] As used in the description herein and throughout the claims that follow, “a,” “an,” and “the” include plural references unless otherwise indicated. Likewise, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless otherwise indicated.

[0085] The above description of the illustrated embodiments of the present invention is not intended to be exhaustive or to limit the invention to the precise forms disclosed herein. Although specific embodiments of the present invention and examples of the present invention are described herein for illustrative purposes only, as those skilled in the art will recognize and appreciate, various equivalent modifications are possible within the spirit and scope of the present invention. As noted, modifications may be made to the present invention in light of the above description of the embodiments of the present invention, and such modifications will be within the spirit and scope of the present invention.

[0086] Systems and methods have been generally described herein in detail to facilitate understanding of the present invention. In addition, various specific details have been given to provide an overall understanding of embodiments of the present invention. However, those skilled in the relevant art will recognize that embodiments of the present invention may be practiced without one or more of these specific details, or with other devices, systems, accessories, methods, components, materials, parts, etc. In other cases, well-known structures, materials, and / or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention.

[0087] Thus, although the invention has been described herein with reference to specific embodiments thereof, freedom of modification, various changes and substitutions are contemplated within the foregoing disclosure, and it should be understood that in some cases, some features of the invention will be employed without the corresponding use of other features without departing from the scope and spirit of the claimed invention. Thus, many modifications may be made to adapt a particular environment or material to the true scope and spirit of the invention. The invention is not intended to be limited to the specific terminology used in the claims below and / or to the specific embodiments disclosed as the best mode contemplated for carrying out the invention, but the invention is intended to include any and all embodiments and equivalents falling within the scope of the appended claims. Thus, the scope of the invention will be determined solely by the appended claims.

Claims

1. A system for rapidly preparing sludge-based derivative fuel using waste heat from cement kilns, characterized in that: include: A feeding unit, the feeding unit includes a sludge storage bin; The sludge drying unit includes an integrated dryer and a drying tower. The dryer is a horizontal paddle structure. The feed port at one end is connected to the sludge storage bin, and the discharge port at the other end is directly connected to the feed port at the bottom of the drying tower. A tangential air inlet is provided near the feed port of the dryer. The heat source supply unit is fed into the drying machine through a side air inlet; The discharging unit includes a bag dust collector and a mixing tank connected thereto. The bag dust collector receives the dried product discharged from the top of the drying tower, and the mixing tank is arranged on the discharge port pipeline of the bag dust collector. The tail gas treatment unit processes the gas discharged from the bag filter; Among them, the dried sludge output from the mixing tank is pneumatically transported to the decomposition furnace of the cement kiln.

2. The system for rapidly preparing sludge-based derived fuel using waste heat from cement kilns according to claim 1, characterized in that: The drying tower is a swirl airflow drying tower. There are three layers of annular guide plates arranged vertically inside the drying tower, and the rotation directions of adjacent guide plates are opposite. It is also equipped with a rotating crushing shaft, and each rotating crushing shaft is evenly provided with serrated crushing blades.

3. The system for rapidly preparing sludge-based derived fuel using waste heat from cement kilns according to claim 1, characterized in that: The discharging unit further comprises a metering feeder, which is arranged on the discharge port pipeline of the bag filter.

4. The system for rapidly preparing sludge-based derived fuel using waste heat from cement kilns according to claim 3, characterized in that: The discharging unit also includes a compressed air tank and a pressure regulating device. The compressed air tank is connected to the mixing tank through a pipeline, and the dried sludge in the mixing tank is transported to the cement kiln decomposition furnace through the air pressure difference.

5. The system for rapidly preparing sludge-based derived fuel using waste heat from cement kilns according to claim 1, characterized in that: The heat source supply unit includes an induced draft fan, a three-way air inlet pipeline and a proportional control valve. The outlet pipe of the fan is connected to the tangential air inlet of the dryer. The first line of the three-way air inlet pipeline is connected to the cement kiln exhaust gas outlet of the cement kiln waste heat power generation system, the second line is connected to the outlet pipeline of the tail gas treatment unit, and the third line is connected to the outside atmosphere. The proportional control valve is used to control the mixing ratio of the cement kiln exhaust gas introduced through the two-way air inlet pipeline and the dry exhaust gas obtained from the tail gas treatment unit.

6. The system for rapidly preparing sludge-based derived fuel using waste heat from cement kilns according to claim 1, characterized in that: The tail gas treatment unit includes a condensation heat exchanger, a catalytic oxidation reactor, a biological deodorizer and an exhaust fan which are sequentially connected in series. The condensation dehumidifier is arranged on the air outlet pipeline of the bag filter.

7. The system for rapidly preparing sludge-based derived fuel using waste heat from cement kilns according to claim 6, characterized in that: The cooling medium outlet of the condensing heat exchanger is connected to the sludge storage bin through a pipeline for preheating the feed sludge.

8. The system for rapidly preparing sludge-based derived fuel using waste heat from cement kilns according to claim 7, characterized in that: A temperature and humidity sensor is provided on the outlet pipeline at the top of the drying tower to measure the temperature and humidity of the dried product at the outlet of the drying tower.

9. The system for rapidly preparing sludge-based derived fuel using waste heat from cement kilns according to claim 8, characterized in that: The outlet pipeline of the bag filter is equipped with a near-infrared online detector and an X-ray fluorescence spectrometer to monitor the calorific value and chlorine and sulfur content of the dried sludge in real time.

10. A method for rapidly preparing sludge-based derivative fuel using waste heat from a cement kiln, characterized in that: The following steps are involved: The wet sludge with a moisture content of ≥60% is passed into the dryer and contacted with the 180-220℃ cement kiln exhaust gas for pre-drying; After pre-drying, the sludge enters the drying tower for further dehydration until the moisture content is less than 10% to obtain a dried product; The dried product is separated into dry sludge and dry waste gas through a bag dust collector. The dry sludge is pneumatically conveyed to the cement kiln decomposition furnace; the treated dry waste gas is passed into the dryer for recycling; According to the temperature and humidity at the drying tower outlet, the intake ratio of cement kiln exhaust gas and recycled dry exhaust gas is dynamically adjusted to control temperature fluctuation to ≤±5℃; the calorific value of dry sludge is monitored, and the intake temperature of the dryer and the sludge residence time are adjusted according to the calorific value feedback.

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