Staged cement kiln alternative fuel low-temperature drying system
By using a staged cement kiln alternative fuel low-temperature drying system, the exhaust gas from the kiln head and AQC boiler is used to establish first and second air chambers, respectively. This solves the problem of high moisture content in the alternative fuel, enables the efficient production of high-quality fuel suitable for both the kiln tail and the kiln head, and improves the thermal efficiency and environmental performance of the cement kiln.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ANHUI CONCH DESIGN & RES INST OF BUILDING MATERIALS CO LTD
- Filing Date
- 2025-04-30
- Publication Date
- 2026-05-05
AI Technical Summary
In existing cement production, alternative fuels such as biomass fuel and waste-derived fuel have high moisture content and low calorific value. Direct use of these fuels will reduce the thermal efficiency of cement kilns. Furthermore, existing drying equipment has strict requirements on the size and shape of material particles, which makes it difficult to meet the requirements of decomposition furnaces and kiln head burners.
A staged cement kiln alternative fuel low-temperature drying system is adopted, which uses the exhaust gas from the kiln head and the AQC boiler to set up the first and second air chambers respectively. The belt dryer processes the material in different temperature ranges to meet the fuel requirements of the kiln tail decomposition furnace and the kiln head burner respectively.
It has achieved efficient drying of large quantities of alternative fuels, producing high-quality alternative fuels suitable for kiln tail decomposition furnaces and kiln head burners, reducing energy consumption and emissions, and improving the thermal efficiency of cement kilns.
Smart Images
Figure CN224202107U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of fuel drying, specifically to a graded low-temperature drying system for alternative fuels in cement kilns. Background Technology
[0002] Cement production, as a high-energy-consuming and high-emission industry, traditionally relies mainly on fossil fuels such as coal and natural gas as heat sources. This not only consumes large amounts of non-renewable resources but also generates significant amounts of greenhouse gases and pollutants. The cement industry urgently needs to find clean, low-carbon alternative fuels, such as biomass fuels and waste-derived fuels (RDF). However, these alternative fuels generally suffer from problems such as high water content, low calorific value, and poor combustion stability. Direct use of these fuels would reduce the thermal efficiency of cement kilns and increase energy consumption and emissions.
[0003] For the drying needs of alternative fuels (such as biomass fuels and waste-derived fuel RDF), the market offers rotary dryers, fluidized bed dryers, and belt dryers. Rotary dryers and fluidized bed dryers have high requirements for material particle size and shape and have relatively low processing capacity; therefore, through-flow belt dryers are more commonly used. Their principle is that the material moves through the drying chamber via a conveyor belt, and hot air passes through the material from above or below, achieving drying. They offer advantages such as continuous operation, large processing capacity, simple structure, and ease of operation.
[0004] Currently, cement kiln alternative fuel drying technology uses low-temperature exhaust gas (80-110℃) at the kiln head as a heat source and employs a belt dryer to dry the alternative fuel. However, for biomass alternative fuels with high moisture content (45%-50%), the moisture content after drying is generally 15%-25%. While this high moisture content can meet the requirements for alternative fuel in the kiln tail decomposition furnace, it is unsuitable for use as alternative fuel in the cement kiln head burner. Simply increasing the drying time and improving quality would inevitably increase equipment size and reduce the amount of alternative fuel that can be processed. Therefore, a staged low-temperature drying system for cement kiln alternative fuels is needed to simultaneously dry large quantities of alternative fuel while producing high-quality alternative fuel that meets the requirements of both the decomposition furnace and the kiln head burner. Utility Model Content
[0005] The purpose of this utility model embodiment is to provide a graded cement kiln alternative fuel low-temperature drying system. This low-temperature drying system can dry a large quantity of alternative fuels while simultaneously producing high-quality alternative fuels that meet the requirements of the decomposition furnace and kiln head burner.
[0006] To achieve the above objectives, this utility model provides a staged cement kiln alternative fuel low-temperature drying system, the low-temperature drying system comprising:
[0007] The first air chamber is where air is drawn in after being exhausted by the kiln head fan, and then drawn in by the induced draft fan so that the airflow passes through the first air chamber.
[0008] The second air chamber is located on the side of the first air chamber, and the second air chamber draws air from the inlet of the AQC boiler and draws air through the induced draft fan so that the airflow passes through the second air chamber;
[0009] A belt dryer section is located in the first air chamber, and the belt dryer section carries materials to be dried. The materials in the lower half of the belt dryer section are burned in the decomposition furnace after drying.
[0010] The second section of the belt dryer is located on the side of the upper half of the first section of the belt dryer, and continues to dry the material conveyed from the upper half of the first section of the belt dryer in the second air chamber.
[0011] Optionally, the upper half of the first section of the belt dryer is designated as Zone A, and the lower half as Zone B, both located within the first air chamber. Zones A and B are separated by a partition. At both ends of Zone B of the first section of the belt dryer, a first double-spiral feeding machine and a first spiral feeder are respectively provided for feeding and discharging materials. A second double-spiral feeding machine is provided on the side of Zone A of the first section of the belt dryer for feeding materials. The second section of the belt dryer is located on the other side of Zone A to receive materials conveyed from Zone A.
[0012] Optionally, a second spiral feeder is provided at the end of the second section of the belt dryer that is away from the first section of the belt dryer.
[0013] Optionally, the first air chamber is divided into four smaller air chambers, each completely separated from the others, with each smaller air chamber corresponding to one of the induced draft fans to control the airflow in each smaller air chamber.
[0014] Optionally, the second air chamber is divided into two smaller air chambers, each completely separated, and each smaller air chamber corresponds to one of the induced draft fans.
[0015] Optionally, the low-temperature drying system includes a bag dust collector, which is connected to the induced draft fan of the first air chamber and the induced draft fan of the second air chamber, respectively, so as to discharge the exhaust gas after dust collection, and the bag dust collector connected to the second air chamber is exhausted through the kiln head fan.
[0016] Optionally, the low-temperature drying system includes a cold air valve installed on the pipe connecting the AQC boiler and the second air chamber to introduce cold air and reduce the temperature of the gas discharged from the AQC boiler.
[0017] Optionally, the low-temperature drying system includes a high-efficiency cyclone separator disposed between the cold air valve and the second air chamber, so as to send the cooled gas into the second air chamber after passing through a high-efficiency dust collector.
[0018] Optionally, a material layer and a mesh belt are provided at the air inlets of both the first and second air chambers.
[0019] Through the above technical solution, the present invention provides a staged cement kiln alternative fuel low-temperature drying system. This system includes a first air chamber, which draws in air from the kiln head fan after exhaust, with the exhaust gas temperature between 80 and 110°C. The airflow can also be drawn in by an induced draft fan, allowing the airflow to pass through the first air chamber. A second air chamber can be located to the side of the first air chamber, and this second air chamber draws in air from the AQC boiler inlet, with a temperature between 330 and 350°C. The airflow can also be drawn in by an induced draft fan, allowing the airflow to pass through the second air chamber. A belt dryer section can be located within the first air chamber, and the material to be dried can be transported along this belt dryer section. The material in the lower half of this belt dryer section can be dried and then burned in the decomposition furnace. The reduced moisture content of the material dried in the first air chamber meets the combustion requirements of the kiln tail decomposition furnace. The second stage of the belt dryer can be located on the side of the upper half of the first stage and within the second air chamber, allowing for continued drying of materials conveyed from the upper half of the belt dryer to meet the fuel combustion requirements of the kiln head burner. This low-temperature drying system can simultaneously dry large quantities of alternative fuels while producing high-quality alternative fuels that meet the requirements of the decomposition furnace and kiln head burner.
[0020] Other features and advantages of this utility model embodiment will be described in detail in the following detailed description section. Attached Figure Description
[0021] The accompanying drawings are provided to further illustrate the embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:
[0022] Figure 1 This is a schematic diagram of a graded cement kiln alternative fuel low-temperature drying system according to one embodiment of the present invention;
[0023] Figure 2 This is a schematic diagram of a section of a belt dryer in a graded cement kiln alternative fuel low-temperature drying system according to one embodiment of the present invention.
[0024] Explanation of reference numerals in the attached figures
[0025] 1. First air chamber 2. Kiln head fan
[0026] 3. Exhaust fan 4. Second air chamber
[0027] 5. AQC boiler; 6. One section of belt dryer
[0028] 7. Two-stage belt dryer; 8. First double-spiral fabric feeder.
[0029] 9. First spiral feeder; 10. Second twin-spiral material distributor
[0030] 11. Second spiral feeder 12. Bag dust collector
[0031] 13. Cold air valve 14. High-efficiency cyclone separator Detailed Implementation
[0032] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.
[0033] Figure 1 This is a schematic diagram of a staged cement kiln alternative fuel low-temperature drying system according to one embodiment of the present invention. The low-temperature drying system may include: a first air chamber 1, a second air chamber 4, a first section of a belt dryer 6, and a second section of a belt dryer 7. The first air chamber 1 can draw air from the kiln head fan 2, with the exhaust gas temperature between 80 and 110°C, and can be induced by an induced draft fan 3, allowing the airflow to pass through the first air chamber 1. The second air chamber 4 can be located on the side of the first air chamber 1, and can draw air from the inlet of the AQC boiler 5, with the air temperature between 330 and 350°C, and can be induced by an induced draft fan 3, allowing the airflow to pass through the second air chamber 4, thereby increasing the temperature within the second air chamber 4 and achieving better material drying. The first section of the belt dryer 6 can be located within the first air chamber 1, and can transport the material to be dried on the first section of the belt dryer 6. The material in the lower half of the first section of the belt dryer 6 can be burned in the decomposition furnace after drying. The second stage 7 of the belt dryer can be located on the side of the upper half of the first stage 6 of the belt dryer, and can be located within the second air chamber 4, thus continuing to dry the material conveyed from the upper half of the first stage 6 of the belt dryer. The material handling capacity of the first stage 6 of the belt dryer is about 18 t / h, with a moisture content of 45% to 50%. After drying, the material capacity is about 12 t / h, with a moisture content of about 20%, and the evaporation rate is more than 6 t / h. Of this, 8 t / h of the dried material is used directly as fuel for combustion in the kiln tail decomposition furnace; the remaining 4 t / h of the dried material is further fed into the second air chamber 4 for drying, resulting in a dried material capacity of about 3.4 t / h, with a moisture content of less than 5%, which is then used directly for combustion in the kiln head burner.
[0034] In one embodiment of this utility model, such as Figure 2 As shown, the upper part of section 6 of the belt dryer can be zone A, and the lower part can be zone B. Both zones A and B can be located within the first air chamber 1. Zones A and B can be separated by a partition. At both ends of zone B of section 6, a first double-spiral feeder 8 and a first spiral feeder 9 can be respectively installed for feeding and discharging. A second double-spiral feeder 10 can be installed on the side of zone A of section 6 for feeding. Section 7 of the belt dryer can be located on the other side of zone A to receive materials conveyed from zone A.
[0035] The second section 7 of the belt dryer, located away from the first section 6, can be equipped with a second spiral feeder 11. When drying is required, the material can be distributed evenly across zones A and B of the first section 6 by the first double spiral feeder 8 and the second double spiral feeder 10. After drying in the first air chamber 1, the material near zone A can leave the first section 6 and enter the second section 7 of the belt dryer. After being dried by higher hot air, it can be unloaded by the second spiral feeder 11 and transported to the storage yard via a conveyor, or directly to the kiln head burner. The material near zone B can be unloaded directly by the first spiral feeder 9 after drying and transported to the storage yard via a conveyor, or directly to the kiln tail decomposition furnace.
[0036] In one embodiment of this utility model, the first air chamber 1 can be divided into four smaller air chambers. Each smaller air chamber can be completely separated from the others, and each smaller air chamber can correspond to one induced draft fan 3. Each induced draft fan 3 can control the air volume of one air chamber, thereby enabling air volume regulation.
[0037] In one embodiment of this invention, the second air chamber 4 can be divided into two smaller air chambers. Each air chamber can be completely separated, and each smaller air chamber can correspond to a blower 3. The blower 3 can regulate the airflow in the smaller air chambers of the second air chamber 4.
[0038] In one embodiment of this utility model, such as Figure 1 As shown, the low-temperature drying system may include baghouse dust collectors 12. There may be two baghouse dust collectors 12, one connected to the induced draft fan 3 of the first air chamber 1 and the other to the induced draft fan 3 of the second air chamber 4, thereby collecting the exhaust gas before discharge. The baghouse dust collector 12 connected to the second air chamber 4 can exhaust air through the kiln head fan 2, and after exhaust, it can take in air and transport it back to the first air chamber 1, thus forming a circulation with the first air chamber 1.
[0039] In one embodiment of this utility model, such as Figure 1 As shown, the low-temperature drying system may include a cold air valve 13. The cold air valve 13 can be installed on the pipe connecting the AQC boiler 5 and the second air chamber 4, thereby allowing cold air to be introduced and reducing the temperature of the gas discharged from the AQC boiler 5. After the gas discharged from the AQC boiler 5 is mixed with cold air through the cold air valve 13, the temperature can be reduced to 180–200°C.
[0040] In one embodiment of this utility model, such as Figure 1 As shown, the low-temperature drying system may include a high-efficiency cyclone separator 14. The high-efficiency cyclone separator 14 may be disposed between the cold air valve 13 and the second air chamber 4, so that the hot air passing through the cold air valve 13 is sent into the second air chamber 4 after being collected by the high-efficiency cyclone separator for dust removal, in order to dry the material.
[0041] In one embodiment of this utility model, the air inlets of the first air chamber 1 and the second air chamber 4 can both be provided with a material layer and a mesh belt, so as to filter the gas passing through the material layer and the mesh belt.
[0042] Through the above technical solution, the present invention provides a staged cement kiln alternative fuel low-temperature drying system. This system includes a first air chamber, which draws in air from the kiln head fan after exhaust, with the exhaust gas temperature between 80 and 110°C. The airflow is also drawn in by an induced draft fan, allowing the air to pass through the first air chamber. A second air chamber can be located to the side of the first air chamber, and it draws in air from the AQC boiler inlet, with a temperature between 330 and 350°C. This second air chamber also draws in air from an induced draft fan, allowing the airflow to pass through it. A belt dryer section can be located within the first air chamber, and the material to be dried can be transported along this section. The material in the lower half of the belt dryer section can be dried and then burned in the decomposition furnace. The material dried in the first air chamber has a reduced moisture content, which meets the combustion requirements of the kiln tail decomposition furnace. The second stage of the belt dryer can be located on the side of the upper half of the first stage and within the second air chamber, allowing for continued drying of materials conveyed from the upper half of the belt dryer to meet the fuel combustion requirements of the kiln head burner. This low-temperature drying system can simultaneously dry large quantities of alternative fuels while producing high-quality alternative fuels that meet the requirements of the decomposition furnace and kiln head burner.
[0043] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.
[0044] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.
Claims
1. A graded cement kiln alternative fuel low-temperature drying system, characterized in that, The low-temperature drying system includes: The first air chamber (1) is where air is drawn in after being exhausted by the kiln head fan (2), and then drawn in by the induced draft fan (3) so that the airflow passes through the first air chamber (1). The second air chamber (4) is located on the side of the first air chamber (1), and the second air chamber (4) draws air from the inlet of the AQC boiler (5) and draws air through the induced draft fan (3) so that the airflow passes through the second air chamber (4); A belt dryer section (6) is set in the first air chamber (1), and the belt dryer section (6) carries materials to be dried. The materials in the lower half of the belt dryer section (6) are burned in the decomposition furnace after drying. The second section (7) of the belt dryer is located on the side of the upper half of the first section (6) of the belt dryer and continues to dry the material conveyed from the upper half of the first section (6) of the belt dryer in the second air chamber (4).
2. The low-temperature drying system according to claim 1, characterized in that, The upper half of the first section (6) of the belt dryer is area A, and the lower half is area B. Both are located in the first air chamber (1) and are separated by a partition. At both ends of area B of the first section (6), a first double spiral feeder (8) and a first spiral feeder (9) are respectively provided for feeding and discharging. A second double spiral feeder (10) is provided on the side of area A of the first section (6) of the belt dryer for feeding. The second section (7) of the belt dryer is located on the other side of area A to receive the material conveyed from area A.
3. The low-temperature drying system according to claim 2, characterized in that, The second spiral feeder (11) is provided at the end of the second section (7) of the belt dryer that is away from the first section (6).
4. The low-temperature drying system according to claim 1, characterized in that, The first air chamber (1) is divided into four small air chambers, each of which is completely separated from the others. Each small air chamber corresponds to one of the induced draft fans (3) to control the air volume of each small air chamber.
5. The low-temperature drying system according to claim 1, characterized in that, The second air chamber (4) is divided into two small air chambers, each of which is completely separated, and each small air chamber corresponds to one of the induced draft fans (3).
6. The low-temperature drying system according to claim 1, characterized in that, The low-temperature drying system includes a bag dust collector (12), which is connected to the induced draft fan (3) of the first air chamber (1) and the induced draft fan (3) of the second air chamber (4) respectively, so as to discharge the exhaust gas after dust collection, and the bag dust collector (12) connected to the second air chamber (4) is exhausted by the kiln head fan (2).
7. The low-temperature drying system according to claim 1, characterized in that, The low-temperature drying system includes a cold air valve (13) installed on the pipe connecting the AQC boiler (5) and the second air chamber (4) to introduce cold air and reduce the temperature of the gas discharged from the AQC boiler (5).
8. The low-temperature drying system according to claim 7, characterized in that, The low-temperature drying system includes a high-efficiency cyclone separator (14) disposed between the cold air valve (13) and the second air chamber (4) to send the cooled gas into the second air chamber (4) after passing through a high-efficiency dust collector.
9. The low-temperature drying system according to claim 1, characterized in that, Material layers and mesh belts are provided at the air inlets of the first air chamber (1) and the second air chamber (4).