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Urea-solution-based SCR (selective catalytic reduction) flue gas denitration process and device

A technology of solution and urea, which is applied in the separation of dispersed particles, chemical instruments and methods, separation methods, etc., can solve the problems of unsatisfactory pyrolysis effect, complex structure of pyrolysis chamber, and high operating cost, so as to simplify the approval procedures and eliminate Potential safety hazards and environmental risks, and the effect of reducing operating costs

Inactive Publication Date: 2012-08-01
湖南安普诺环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this technology is that natural gas or oil is used as the heat source, and the operating cost is high
In the Chinese patent literature, "Direct injection urea method SCR flue gas denitrification process and device" (patent application number: 201010582020.6) is to spray solid urea powder directly into the flue, and use the temperature of the flue gas to pyrolyze the urea into gaseous ammonia. The pyrolysis effect is not ideal; "A urea ammonia production process and system for boiler flue gas denitrification" (patent application number: 201010252649.4) is the patented technology of the urea pyrolysis ammonia production process of FUEL TECH in the United States. Improvement, the natural wind is heated by high-temperature flue gas to produce pyrolysis air. This scheme also uses the pyrolysis chamber mentioned in the patent of FUEL TECH in the United States to pyrolyze the urea solution. It also has the complex structure of the pyrolysis chamber and large investment Shortcomings

Method used

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  • Urea-solution-based SCR (selective catalytic reduction) flue gas denitration process and device
  • Urea-solution-based SCR (selective catalytic reduction) flue gas denitration process and device
  • Urea-solution-based SCR (selective catalytic reduction) flue gas denitration process and device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] Example 1: SCR flue gas denitrification process and device based on urea solution:

[0045] Such as figure 1 As shown, the pyrolysis air is drawn from the secondary air duct behind the air preheater, and after being pressurized by the first fan (pressurization range 6000-10000Pa, meeting the pressure requirements of the ammonia injection grid), the pyrolysis air heater The interior is heated to 350-700°C by boiler flue gas;

[0046] The prepared 30%-50% urea solution is stored in the storage tank, the flow rate is controlled by the urea solution pump and the metering distribution device, and sprayed into the above-mentioned heated pyrolysis air by the atomizing spray gun;

[0047] The atomized urea is quickly pyrolyzed into gaseous ammonia at high temperature, reaching the safety index of 2 , to complete the denitrification process.

[0048] The first fan adopts a frequency conversion fan, and the pyrolysis air volume is controlled by frequency conversion to match the...

Embodiment 2

[0051] Embodiment 2: SCR flue gas denitrification process and device based on ammonia water:

[0052] Such as figure 1 As shown, the pyrolysis air is extracted from the outside of the furnace, and after being pressurized to 6000-10000Pa by the pyrolysis fan, it is heated to 350-700°C by the boiler flue gas in the pyrolysis air heater.

[0053] The 15%-20% ammonia solution is stored in the storage tank, and the flow is controlled by the ammonia water pump and the metering distribution device, and sprayed into the above-mentioned heated pyrolysis air by the spray gun;

[0054] The atomized ammonia is quickly gasified into gaseous ammonia at high temperature, sprayed evenly into the intake flue of the denitrification reactor through the ammonia injection grid, fully mixed with the flue gas through the mixer, and evenly enters the denitrification reaction after passing through the guide plate and the rectifier device, under the action of a catalyst, NO in the flue gas is reduced ...

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Abstract

The invention discloses a urea-solution-based SCR (selective catalytic reduction) flue gas denitration process and device. According the process, pyrolysis air is pumped from the outside or a second air channel of a boiler, then is pressurized by a first fan and heated to 350-700 DEG C by a pyrolysis air heater arranged in a boiler hearth or a tail air channel, and the heated pyrolysis air enters a pyrolysis reaction air channel together with fresh air; urea solution is sprayed into the pyrolysis air channel by an atomizing spray gun and the atomized urea solution is pyrolyzed into ammonia gas in the pyrolysis air channel; and after being discharged out of the pyrolysis air channel, the ammonia gas is sprayed into boil flue gas via ammonia spraying grilles to participate in the SCR reaction in an SCR reactor arranged in a tail flue of the boiler. the urea-solution-based SCR flue gas denitration process and device have the advantages of high safety, simple structure and easiness in implementation.

Description

technical field [0001] The invention belongs to the technical field of flue gas nitrogen oxide emission reduction (denitration) and relates to a urea solution-based SCR flue gas denitrification process and device. Background technique [0002] Flue gas selective catalytic reduction (SCR) denitrification process is currently the main technology for flue gas denitrification. The SCR process is a selective reduction reaction between the amino reducing agent and the NO in the flue gas under the action of a catalyst to generate N 2 and water, thereby eliminating pollution. In order to ensure the effect of mixing and reaction, the ammonia reducing agent is required to be evenly sprayed into the flue in gaseous form through the ammonia spraying grid, so the reducing agent is usually liquid ammonia that is easy to evaporate. However, liquid ammonia is a dangerous chemical, and its transportation and storage are strictly restricted, which brings more inconvenience to the initial co...

Claims

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Application Information

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IPC IPC(8): B01D53/56B01D53/90
Inventor 彭峻
Owner 湖南安普诺环保科技有限公司
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