A new type of dry process cement kiln using external decomposition furnace to reduce NOx emissions

Abstract

The invention discloses a novel dry process cement kiln using an external decomposition furnace to reduce NOx emission technology, belonging to the technical field of cement production, including an original cement rotary kiln system and an external decomposition furnace system, wherein the original cement rotary kiln system includes an original decomposition furnace and a kiln tail smoke chamber, wherein the output end of the kiln tail smoke chamber is fixedly connected to the input end of the original decomposition furnace. The invention uses a pulverized coal burner installed on one side of the external decomposition furnace to facilitate mixing pulverized coal with high-temperature flue gas discharged from the inside of the cement rotary kiln, and burning to produce CO and H2 under the regulation of lack of oxygen, and uses CO and H2 as reducing agents to reduce NOx in the high-temperature flue gas generated by the cement rotary kiln, and uses a distributing valve installed to control the flue gas temperature in the external furnace by adjusting the amount of pulverized coal fed, and uses a decomposition furnace shrinkage gate valve installed to extend the contact time of pulverized coal with high-temperature flue gas under the condition of lack of oxygen, thereby improving the NOx reduction efficiency, reducing the NOx emission, and increasing the effective volume of the decomposition furnace.

Description

Technical Field

[0001] The invention relates to a NOx emission reduction technology for a decomposition furnace, and in particular to a NOx emission reduction technology for a novel dry-process cement kiln using an external decomposition furnace. Background Art

[0002] Cement kilns are generally equipped with SNCR denitrification technology, which reduces NOx emissions by spraying ammonia water. The daily operating cost of this technology is high, and it is difficult to control emissions to less than 100mg / Nm3. At present, key areas require cement kiln emission indicators to be controlled within 100mg / Nm3. Most manufacturers use thermal technology and SNCR denitrification technology to reduce NOx emissions by controlling the excess air coefficient of the decomposition furnace and forming a reducing atmosphere in the local area of ​​the furnace. The NOx emission value can basically be controlled within 100mg / Nm3. However, the staged combustion technology changes the original distribution of wind, coal, and materials in the decomposition furnace, occupies part of the decomposition furnace volume, and the decomposition furnace is prone to problems such as material collapse and crusting, resulting in a decrease in production. Summary of the invention

[0003] The purpose of the present invention is to provide a novel dry process cement kiln using an external decomposition furnace to reduce NOx emissions, so as to solve the problem that the staged combustion technology proposed in the above background technology changes the original distribution of wind, coal and materials in the decomposition furnace, occupies part of the decomposition furnace volume, and the decomposition furnace is prone to problems such as material collapse and crusting, resulting in a decrease in production.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a novel dry process cement kiln uses an external decomposition furnace to reduce NOx emission technology, including an original cement rotary kiln system and an external decomposition furnace system, the original cement rotary kiln system includes an original decomposition furnace and a kiln tail smoke chamber, the output end of the kiln tail smoke chamber is fixedly connected to the input end of the original decomposition furnace, the external decomposition furnace system includes an external decomposition furnace, a pulverized coal burner, a material spreading box, an external furnace gate valve and a material distribution valve, the inlet end of the external decomposition furnace is connected to the side of the kiln tail smoke chamber through a conduit The external decomposition furnace is internally connected, the outlet end of the external decomposition furnace is connected with the interior of one side of the original decomposition furnace through a conduit, an external decomposition furnace gate valve is fixedly installed on the top of the external decomposition furnace, a material spreading box is fixedly installed on the top of one side of the external decomposition furnace, a pulverized coal burner is fixedly installed on the bottom of the material spreading box, the top of the material spreading box is fixedly connected with one end of a material distribution valve through a conduit, the other end of the material distribution valve is connected with the interior of the original decomposition furnace through a conduit, and a decomposition furnace shrinkage gate valve is fixedly installed at the connection between the original decomposition furnace and the kiln tail smoke chamber.

[0005] As a preferred technical solution of the present invention, the input end of the kiln tail smoke chamber is fixedly connected to the output end of the cement rotary kiln, and a sealing ring is provided at the connection part.

[0006] As a preferred technical solution of the present invention, the kiln tail smoke chamber of the original cement rotary kiln system draws out high-temperature flue gas, and the high-temperature flue gas enters the external decomposition furnace.

[0007] As a preferred technical solution of the present invention, the dividing valve can adopt a dividing valve with a model of "55" on the market, and the pulverized coal burner can adopt a pulverized coal burner with a model of "2-5 million kcal" on the market.

[0008] As a preferred technical solution of the present invention, the surfaces of the original decomposition furnace, the external decomposition furnace and the material spreading box are all painted with evenly distributed anti-corrosion paint.

[0009] As a preferred technical solution of the present invention, a switch panel is fixedly installed on one side of the original decomposition furnace, and a pulverized coal burner control switch, an external furnace gate valve control switch, a dividing valve control switch and a decomposition furnace shrinkage gate valve control switch are respectively installed on the surface of the switch panel. The pulverized coal burner, the external furnace gate valve, the dividing valve and the decomposition furnace shrinkage gate valve are electrically connected to an external power supply through the pulverized coal burner control switch, the external furnace gate valve control switch, the dividing valve control switch and the decomposition furnace shrinkage gate valve control switch.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: a novel dry-process cement kiln of the present invention adopts the NOx emission reduction technology of an external decomposition furnace, and a pulverized coal burner installed on one side of the external decomposition furnace is used to facilitate mixing pulverized coal with the high-temperature flue gas discharged from the inside of the cement rotary kiln, and burning to produce CO and H2 under the regulation of hypoxia, and reducing the NOx in the high-temperature flue gas produced by the cement rotary kiln by using CO and H2 as reducing agents, and controlling the flue gas temperature in the external furnace by adjusting the amount of pulverized coal fed through the installed feeder valve, and extending the contact time of pulverized coal with the high-temperature flue gas under hypoxic conditions through the installed decomposition furnace shrinkage gate valve, thereby improving the NOx reduction efficiency, reducing the NOx emission, increasing the effective volume of the decomposition furnace, and improving the system output. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of the present invention.

[0012] In the figure: 1. Original cement rotary kiln system; 2. External decomposition furnace system; 3. Original decomposition furnace; 4. Kiln tail smoke chamber; 5. External decomposition furnace; 6. Pulverized coal burner; 7. Spreading box; 8. External furnace gate valve; 9. Distribution valve; 10. Decomposition furnace shrink gate valve; 11. Cement rotary kiln; 12. Conduit. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] See also Figure 1 The present invention provides a novel dry process cement kiln using an external decomposition furnace to reduce NOx emission technology, comprising an original cement rotary kiln system 1 and an external decomposition furnace system 2, wherein the original cement rotary kiln system 1 comprises an original decomposition furnace 3 and a kiln tail smoke chamber 4, wherein the input end of the kiln tail smoke chamber 4 is fixedly connected to the output end of the cement rotary kiln 11, and a sealing ring is provided at the connection part, and the output end of the kiln tail smoke chamber 4 is fixedly connected to the input end of the original decomposition furnace 3, and the kiln tail smoke chamber 4 of the original cement rotary kiln system 1 draws out high-temperature flue gas, and the high-temperature flue gas The gas enters the external decomposition furnace 5, and the external decomposition furnace system 2 includes the external decomposition furnace 5, the pulverized coal burner 6, the spreading box 7, the external furnace gate valve 8, the material distribution valve 9 and the decomposition furnace shrink gate valve 10. The inlet end of the external decomposition furnace 5 is connected with the inside of the kiln tail smoke chamber 4 through the conduit 12, and the outlet end of the external decomposition furnace 5 is connected with the inside of the original decomposition furnace 3 through the conduit 12. The top of the external decomposition furnace 5 is fixedly installed with the external furnace gate valve 8. The top of the external decomposition furnace 5 is fixed with the external furnace gate valve 8. A material spreading box 7 is fixedly installed, and a pulverized coal burner 6 is fixedly installed at the bottom of the material spreading box 7. The top of the material spreading box 7 is fixedly connected to one end of a distribution valve 9 through a conduit 12, and the other end of the distribution valve 9 is communicated with the interior of the original decomposition furnace 3 through the conduit 12. A decomposition furnace shrinkage gate valve 10 is fixedly installed at the connection between the original decomposition furnace 3 and the kiln tail smoke chamber 4. The pulverized coal burner 6 installed on one side of the installed external decomposition furnace 5 is convenient for mixing pulverized coal with the high-temperature flue gas discharged from the inside of the cement rotary kiln 11, and burning to produce CO and H2 under the regulation of hypoxia. By using CO and H2 as reducing agents to reduce NOx in the high-temperature flue gas generated by the cement rotary kiln 11, and through the installed distribution valve 9, the flue gas temperature in the external furnace is controlled by adjusting the amount of pulverized coal fed, and the decomposition furnace shrinkage gate valve 10 is installed to extend the contact time of pulverized coal with the high-temperature flue gas under hypoxic conditions, thereby improving the NOx reduction efficiency, reducing the NOx emission, increasing the effective volume of the decomposition furnace, and improving the system output.

[0015] The distributing valve 9 can adopt the distributing valve 9 of model "55" on the market, and the pulverized coal burner 6 can adopt the pulverized coal burner 6 of model "2-5 million kcal" on the market. The surfaces of the original decomposition furnace 3, the external decomposition furnace 5 and the spreading box 7 are all painted with evenly distributed anti-corrosion paint. The anti-corrosion paint can extend the service life of the original decomposition furnace 3, the external decomposition furnace 5 and the spreading box 7. A switch panel is fixedly installed on one side of the original decomposition furnace 3, and the surface of the switch panel is respectively installed with the pulverized coal burner control switch, the external furnace gate valve control switch, the distributing valve control switch and the decomposition furnace shrinking gate valve control switch. The pulverized coal burner 6, the external furnace gate valve 8, the distributing valve 9 and the decomposition furnace shrinking gate valve 10 are electrically connected to the external power supply through the pulverized coal burner control switch, the external furnace gate valve control switch, the distributing valve control switch and the decomposition furnace shrinking gate valve control switch.

[0016] In specific use, a novel dry-process cement kiln of the present invention uses an external decomposition furnace to reduce NOx emissions. When it is necessary to use the dry-process cement kiln to use the external decomposition furnace to reduce NOx emissions, firstly, a hole is artificially opened at a suitable position on one side of the kiln tail smoke chamber 4, and then the opening is connected to the inlet of the external decomposition furnace 5 through a conduit 12. The outlet of the external decomposition furnace 5 is connected to the bottom of one side of the original decomposition furnace 3 through the conduit 12. A material spreading box 7 is installed at a suitable position at the inlet of the external decomposition furnace 5, a pulverized coal burner 6 is installed at the bottom of the material spreading box 7, and the top of the material spreading box 7 is fixedly connected to one end of the material distribution valve 9 through the conduit 12. Then the top of the kiln tail smoke chamber 4 is connected to the inlet of the original decomposition furnace 3, and at the kiln tail, a pulverized coal burner 6 is installed at the bottom of the material spreading box 7. The top of the material spreading box 7 is fixedly connected to one end of the material distribution valve 9 through the conduit 12. Then, the top of the kiln tail smoke chamber 4 is connected to the inlet of the original decomposition furnace 3, and at the kiln tail, a pulverized coal burner 6 is installed at the bottom of the material spreading box 7. A decomposition furnace shrinking gate valve 10 is installed at the connection between the smoke chamber 4 and the original decomposition furnace 3 to complete the installation of the equipment. During operation, the decomposition furnace shrinking gate valve 10 is closed by manually opening the distribution valve 9, and the high-temperature flue gas inside the kiln tail smoke chamber 4 enters the external decomposition furnace 5. The amount of coal powder is adjusted by the distribution valve 9. The coal powder passes through the spreading box 7 and the coal powder burner 6 to make the coal powder and the high-temperature flue gas fully mixed, and CO, H2 and other reducing agents are generated under oxygen-deficient conditions. The generated CO, H2 and other reducing agents react with NOx in the high-temperature flue gas to form N2 and related products, effectively reducing NOx emissions and increasing system output. When the system is shut down, the distribution valve 9 is closed and the decomposition furnace shrinking gate valve 10 is opened.

[0017] In the description of the present invention, it is necessary to understand that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0018] In the present invention, unless otherwise clearly stipulated and limited, for example, it can be a fixed connection, a detachable connection, or an integrated one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0019] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A novel dry process cement kiln using an external calciner to reduce NOx emissions technology, comprising an original cement rotary kiln system (1) and an external calciner system (2), characterized in that: The original cement rotary kiln system (1) comprises an original calciner (3) and a kiln tail smoke chamber (4), the output end of the kiln tail smoke chamber (4) is fixedly connected to the input end of the original calciner (3), the external calciner system (2) comprises an external calciner (5), a pulverized coal burner (6), a material spreading box (7), an external calciner gate valve (8) and a material distribution valve (9), the inlet end of the external calciner (5) is connected to the interior of one side of the kiln tail smoke chamber (4) through a conduit (12), and the outlet end of the external calciner (5) is connected to the interior of one side of the original calciner (3) through a conduit (12). The external decomposition furnace (5) is connected to the outside, an external furnace gate valve (8) is fixedly installed on the top of the external decomposition furnace (5), a material spreading box (7) is fixedly installed on the top of one side of the external decomposition furnace (5), a pulverized coal burner (6) is fixedly installed on the bottom of the material spreading box (7), the top of the material spreading box (7) is fixedly connected to one end of a material distribution valve (9) through a conduit (12), the other end of the material distribution valve (9) is connected to the inside of the original decomposition furnace (3) through a conduit (12), and a decomposition furnace shrink gate valve (10) is fixedly installed at the connection between the original decomposition furnace (3) and the kiln tail smoke chamber (4).

2. According to claim 1, a novel dry process cement kiln using an external decomposition furnace to reduce NOx emissions is characterized by: The input end of the kiln tail smoke chamber (4) is fixedly connected to the output end of the cement rotary kiln (11), and a sealing ring is sleeved on the connection part.

3. The novel dry process cement kiln using an external decomposition furnace to reduce NOx emissions according to claim 1 is characterized in that: The kiln tail smoke chamber (4) of the original cement rotary kiln system (1) draws out high-temperature flue gas, and the high-temperature flue gas enters the external decomposition furnace (5).

4. The novel dry process cement kiln using an external decomposition furnace to reduce NOx emissions according to claim 1 is characterized in that: The surfaces of the original decomposition furnace (3), the external decomposition furnace (5) and the material spreading box (7) are all painted with evenly distributed anti-corrosion paint.

5. The novel dry process cement kiln using an external decomposition furnace to reduce NOx emissions according to claim 1 is characterized in that: A switch panel is fixedly installed on one side of the original decomposition furnace (3), and a pulverized coal burner control switch, an external furnace gate valve control switch, a material distribution valve control switch and a decomposition furnace shrink gate valve control switch are respectively installed on the surface of the switch panel. The pulverized coal burner (6), the external furnace gate valve (8), the material distribution valve (9) and the decomposition furnace shrink gate valve (10) are electrically connected to an external power supply through the pulverized coal burner control switch, the external furnace gate valve control switch, the material distribution valve control switch and the decomposition furnace shrink gate valve control switch.

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