Raw material homogenizing silo external circulation system for reducing pollutant emission of cement kiln

Abstract

The utility model discloses an external circulation system of a raw material homogenizing silo for reducing pollutant emission of a cement kiln, which is characterized in that a large amount of raw material powder in the production process of the cement kiln is fed into a flue gas pipeline, the raw material powder suspended in flue gas adsorbs SO2 or NH3 in gas, and the raw material powder enters a downstream cloth bag dust collector, so that the raw material powder can be recycled. A dust layer is formed on the outer layer of the filter bag to further adsorb SO2 or NH3 of penetrating gas, the adsorbed raw material is subjected to dust collection through the bag collector and then returns to the raw material homogenizing silo, an outer circulation system is formed, and the discharge amount of SO2 or NH3 can be greatly reduced by utilizing the technology.

Description

Technical Field

[0001] The utility model relates to a raw material homogenization storage external circulation system for reducing the pollutant emission of a cement kiln. Background Art

[0002] At present, in order to achieve ultra-low emissions of nitrogen oxides, cement companies mostly use staged combustion + SNCR ammonia injection system for denitrification. In order to ensure the denitrification effect, sometimes there is a large amount of ammonia injection. In addition to being partially oxidized, some of the excess ammonia enters the downstream raw mill and exhaust gas treatment system.

[0003] Another pollutant from cement kilns is SO 2 , mainly from fuel and raw materials. SO generated by fuel combustion in the decomposition furnace and kiln head 2 As the flue gas flows through the preheater, the organic sulfur or ferrous sulfide contained in the raw material is oxidized in the upper part of the preheater to produce SO 2 , part of it comes into contact with the raw meal and is adsorbed by calcium carbonate or calcium oxide in the raw meal. When the sulfur in the fuel or the organic sulfur or ferrous sulfide in the raw material is low, the emission requirements can be met. When the sulfur in the fuel or the organic sulfur or ferrous sulfide in the raw material is high, the excess SO 2 It enters the raw material mill and the exhaust gas treatment system and is further absorbed, which can also meet the emission requirements. If the sulfur in the fuel or the organic sulfur or ferrous sulfide in the raw materials is further increased, a flue gas desulfurization system needs to be added to meet the emission requirements.

[0004] When the raw mill is in operation, the large amount of raw meal powder can 2 or NH 3 Adsorption removal; when the raw mill is shut down, the concentration of raw powder drops sharply, and SO 2 or NH 3 The emission concentration increased significantly. 2 or NH 3 The removal efficiency is generally between 60% and 90%. Due to the need for production and maintenance of the raw mill system, there is generally a 2-4 hour downtime per day. In order to solve the SO 2 or NH 3 To solve the problem of high emissions, the technical solution of this application is proposed. Summary of the invention

[0005] The utility model aims to solve the problems existing in the prior art and provides a raw material homogenization storage external circulation system for reducing the pollutant emission of cement kilns.

[0006] The technical solutions adopted in this utility model are:

[0007] A raw meal homogenization silo external circulation system for reducing pollutant emissions from cement kilns includes a raw meal homogenization silo, a kiln tail flue gas duct, a second bag dust collector, a raw meal mill and a conveying device. The raw meal is conveyed from the raw meal homogenization silo to the kiln tail flue gas duct by the conveying device, and SO is adsorbed in the kiln tail flue gas duct. 2 or NH 3 The kiln tail flue gas duct is connected to the second bag dust collector and the raw meal mill, and the raw meal powder collected by the second bag dust collector is sent back to the raw meal homogenization warehouse by the conveying equipment.

[0008] Furthermore, a first bag dust collector is provided on the conveying path between the raw meal homogenization bin and the kiln tail flue gas duct for collecting dust during the conveying process.

[0009] Furthermore, a metering device is provided at the discharge port of the raw meal homogenization storage.

[0010] Furthermore, the conveying equipment is one or more of an air chute, a chain conveyor, and a bucket elevator.

[0011] The utility model is a raw material homogenization storage external circulation system for reducing pollutant emissions from cement kilns. The structural feature of the utility model is that a large amount of raw material powder is sent into the flue gas pipeline during the production process of the cement kiln. The raw material powder suspended in the flue gas reacts with SO in the gas. 2 or NH 3 The adsorption effect of the raw material powder and the dust layer formed on the outer layer of the filter bag will affect the SO 2 or NH 3 After further adsorption, the raw material after adsorption is collected by the bag dust collector and then returned to the raw material homogenization warehouse to form an external circulation system. This technology can be used to remove SO 2 or NH 3 Emissions are greatly reduced. The resulting beneficial effects are:

[0012] 1) It has the advantages of low investment, few new equipment, low energy consumption, simple layout and small amount of subsequent maintenance work.

[0013] 2) Applicable when the raw mill system is running, SO 2 or NH 3 The emission is qualified. When the raw mill system stops running, SO 2 or NH 3 Systems that emit concentrations exceeding the permitted levels.

[0014] 3) It integrates well with the original raw meal mill system and the kiln tail bag dust collector returning to the raw meal homogenization storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural diagram of the utility model. DETAILED DESCRIPTION

[0016] The utility model is further described below in conjunction with the accompanying drawings.

[0017] like Figure 1 As shown, the utility model is a raw meal homogenization silo external circulation system for reducing pollutant emissions from cement kilns, comprising a raw meal homogenization silo 1, a kiln tail flue gas duct 8, a second bag dust collector 9, a raw meal mill 10 and a conveying device 2 (air chute, chain conveyor, bucket elevator, etc.).

[0018] The utility model constructs an external circulation area between the raw material homogenization bin 1 and the flue gas duct at the outlet of the raw material mill 10. The raw material flows out of the raw material homogenization bin through the conveying device 2, is measured by the metering device 3, and is conveyed into the kiln tail flue gas duct 8. A material spreading box is provided at the connection with the kiln tail flue gas duct 8 to evenly distribute the raw material in the kiln tail flue gas duct 8. The raw material absorbs SO in the material spreading box 8. 2 or NH 3 After the second bag dust collector 9 collects dust, the collected raw meal powder returns to the raw meal homogenization warehouse 1 through the conveying equipment 2, forming an external circulation system.

[0019] The first bag dust collector 5 collects dust during the transportation process of the external circulation system. During the shutdown period of the raw mill 10, the system can collect SO 2 or NH 3 Control emission concentrations during raw mill operation.

[0020] During the shutdown period of the raw mill, raw meal is introduced from the raw meal homogenization storage into the flue gas duct at the raw meal mill outlet. A large amount of raw meal powder in the cement kiln production process is sent into the flue gas duct. The raw meal powder suspended in the flue gas has a great impact on the SO in the gas. 2 or NH 3 The adsorption effect of the raw material powder and the dust layer formed on the outer layer of the filter bag to the SO2 of the passing gas 2 or NH 3 After further adsorption, the adsorbed raw meal is collected in the bag dust collector at the end of the kiln and returned to the raw meal homogenization warehouse, and then enters the kiln system together with the raw meal.

[0021] Compared with other ammonia absorption systems or flue gas desulfurization devices, this system is fully integrated with the original raw mill system, with the advantages of low investment, less new equipment, low energy consumption, simple layout, and less maintenance workload. 2 or NH 3 The emission is qualified. When the raw mill system stops running, SO 2 or NH 3 Systems that emit concentrations exceeding the permitted levels.

[0022] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A raw meal homogenization storage external circulation system for reducing pollutant emissions from cement kilns, characterized in that: The invention comprises a raw meal homogenizing silo (1), a kiln tail flue gas duct (8), a second bag dust collector (9), a raw meal mill (10) and a conveying device. The raw meal is conveyed from the raw meal homogenizing silo (1) to the kiln tail flue gas duct (8) by the conveying device, and SO2 or NH3 is adsorbed in the kiln tail flue gas duct (8). The kiln tail flue gas duct (8) is connected to the second bag dust collector (9) and the raw meal mill (10). The raw meal powder collected by the second bag dust collector (9) is conveyed back to the raw meal homogenizing silo (1) by the conveying device.

2. The raw meal homogenization storage external circulation system for reducing cement kiln pollutant emissions according to claim 1, characterized in that: A first bag dust collector (5) is provided on the conveying path between the raw meal homogenizing bin (1) and the kiln tail flue gas duct (8) for collecting dust during the conveying process.

3. The raw meal homogenization storage external circulation system for reducing cement kiln pollutant emissions according to claim 1, characterized in that: The discharge port of the raw meal homogenization storage (1) is provided with a metering device (3).

4. The raw meal homogenization storage external circulation system for reducing cement kiln pollutant emissions according to claim 1, characterized in that: The conveying equipment is one or more of an air chute, a chain conveyor, and a bucket elevator.

Images