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Method and device for controlling NOx concentration in flue gas of cement furnace

A technology of a control device and a central controller, applied in separation methods, chemical instruments and methods, and separation of dispersed particles, can solve problems affecting the long-term stable operation of cement kiln production lines, threats to normal operation of induced draft fans, and blockage of catalyst pores, etc., to achieve Reduced denitrification costs, reduced tail ammonia escape, and strong adaptability to load fluctuations

Active Publication Date: 2014-10-08
ENVIRONMENTAL SCI RES & DESIGN INST OF ZHEJIANG PROVINCE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the cement kiln dust content as high as 80 ~ 100g / Nm 3 , it is easy to cause catalyst pore blockage, so that the pressure drop of the system increases rapidly, which poses a serious threat to the normal operation of the induced draft fan, thus affecting the long-term stable operation of the cement kiln production line; at the same time, sodium, potassium and other water-soluble alkali metal compounds in the cement kiln flue gas Catalyst V 2 o 5 The reaction leads to poisoning of the catalyst, reducing its activity; in addition, the high concentration of CaO in the flue gas, and the SO oxidized by the catalyst 3 Generate CaSO 4 , covering the catalyst surface and reducing its activity

Method used

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  • Method and device for controlling NOx concentration in flue gas of cement furnace
  • Method and device for controlling NOx concentration in flue gas of cement furnace

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] The spray gun is installed on the exit flue ( figure 1 The injection module shown in the dashed box in A). According to the results of CFD simulation, the injection points are divided into three layers, 2 in each layer, distributed on the circular flue. All spray points fall within the temperature range of 800~950℃. There are spray guns installed at the three levels of the system, and each spray gun is numbered A1, A2, B1, B2, C1, C2. The system is put into automatic operation, according to the system temperature, NO X Concentration, flow and other parameter feedback (temperature changes, the system selects the appropriate temperature window according to the temperature parameter feedback, that is, changes the injection point level; flow changes, what needs to be changed is the amount of system ammonia injection, the change of NSR mainly depends on the NOx concentration Change and change), the system automatically selects points, A1, A2, B1, B2, C1, C2 can select 2-4 spr...

Embodiment 2

[0053] According to the results of CFD simulation, the spray gun is installed in the middle and upper part of the decomposition kiln body ( figure 1 The injection module 3) and the exit flue ( figure 1 The injection module 2 is shown in the dashed frame of middle B), the injection points are divided into two layers, each with 3 (A1, A2, A3, B1, B2, B3). All spray points fall within the temperature range of 800~950℃. According to the system's temperature, concentration, flow and other parameter feedback, the system automatically selects points. A1, A2, A3, B1, B2, and B3 can select 3-6 spray guns, which are actually put into operation.

[0054] The flue gas processing capacity of the denitration system is 3.0×10 5 Nm 3 / h, NOx content 700mg / Nm 3 , Adjust NSR=1.8, kiln tail chimney NO X The concentration is reduced to about 150mg / Nm 3 , The denitration rate fluctuates around 78%.

[0055] Adjust NSR=1.7, kiln tail chimney NO X The concentration is reduced to about 175mg / Nm 3 , The de...

Embodiment 3

[0060] According to the CFD simulation results, it is determined that the outlet flue is vertically upward on the flue gas pipeline ( figure 1 The spraying module 2 is shown in the dashed frame of middle A), the spraying point is one layer, and there are 8 spray guns (A1, A2, A3, A4, A5, A6, A7, A8). All spray points fall within the temperature range of 800~950℃. The spraying points of the system are equipped with spray guns, and the system is put into automatic operation. According to the feedback of the temperature, concentration, flow and other parameters of the system, the system automatically selects the points, A1, A2, A3, A4, A5, A6, A7, A8 are available Select 4-8 spray guns, which are the actual spray gun positions.

[0061] The system automatically selects the point of the spray gun that is actually put into operation.

[0062] The flue gas processing capacity of the denitration system is 6.0×10 5 Nm 3 / h, NOx content 1000mg / Nm 3 , Adjust NSR=1.8, kiln tail chimney NO X ...

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Abstract

The invention discloses a method and device for controlling NOx concentration in smoke gas of a cement kiln; the device comprises a decomposing kiln, a preheater and a reducing agent supply device, wherein the bottom of the decomposing kiln is communicated with a kiln tail chimney of the cement kiln by an inlet smoke flue; the top of the decomposing kiln is communicated with the preheater by an outlet smoke flue; a plurality of spray guns communicated with the reducing agent supply devices are arranged at or / or in the middle upper part of the decomposing kiln or / and the outlet smoke flue in a layered way; and the device further comprises a central controller and a smoke gas automatic monitoring system, wherein the central controller is connected to the reducing agent supply devices; and the smoke gas automatic monitoring system is used for monitoring NOx concentration and smoke gas flow information in the kiln tail chimney and transmitting the NOx concentration and smoke gas flow information to the central controller. According to the invention, as a reducing agent is sprayed into the decomposing kiln through multi-site combined control, high removal rate of the NOx can be achieved without an SNCR (Selective Non Catalytic Reduction) and SCR (Selective Catalytic Reduction) combined technology.

Description

Technical field [0001] The present invention relates to the technical field of chemical environmental protection, in particular to a kind of NO in flue gas of cement kiln x Concentration control method and device. Background technique [0002] According to the generation mechanism of NOx in the cement industry, the control technology for NOx is mainly divided into two categories, one is to control the combustion process to reduce the generation of NOx; the other is to take removal measures for the already generated NOx. The control technology for the combustion process mainly includes low NOx burners, fuel staging combustion, air staging combustion and other means to control oxygen supply or reduce flue gas temperature to reduce the generation of thermal NOx. By monitoring the combustion process, such as the excess air coefficient and flue gas temperature of the rotary kiln, and the concentration of pollutants such as NOx and CO at the exit of the chimney, the combustion is optim...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D53/79B01D53/56
Inventor 顾震宇韦彦斐金瑞奔朱虹范海燕周荣陆建海汪昊其
Owner ENVIRONMENTAL SCI RES & DESIGN INST OF ZHEJIANG PROVINCE
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