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Method for reducing W-type flame boiler NOx emission

A boiler and flame technology, applied in the field of reducing NOx emissions from W-flame boilers, can solve the problems of poor burnout and poor stability of W-flame boilers

Active Publication Date: 2017-11-17
中国大唐集团科学技术研究总院有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a method for solving the technical problems of poor burnout performance of W flame boilers and poor stability at high loads, and improving the burnout rate of pulverized coal to reduce NOx emissions from W-flame boilers

Method used

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  • Method for reducing W-type flame boiler NOx emission
  • Method for reducing W-type flame boiler NOx emission
  • Method for reducing W-type flame boiler NOx emission

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0054] Such as image 3 As shown, in the method for reducing NOx emissions from a W-flame boiler in this embodiment, the fuel is burned in a staged combustion method, which specifically includes: selecting a predetermined proportion of flammable coal and anthracite, and using flammable coal to react with oxygen to become the first stage Combustion, in which the combustible coal is bituminous coal or a mixture of bituminous coal and lean coal; the high-temperature flue gas atmosphere formed in the first stage, under the entrapment of the high-temperature flue gas, ignites anthracite, forming a second-stage combustion. The volatile content is higher than that of anthracite, and the volatile content is more than 25%, and the ratio of bituminous coal: anthracite is greater than 1:1; among them, the volatile content of the ashless coal after entering the furnace is maintained at 15%10% is required.

[0055] In this embodiment, the W-flame boiler uses anthracite coal and has a long igni...

Embodiment 2

[0058] The method for reducing the NOx emission of the W-flame boiler in this embodiment is based on the first embodiment, in order to improve the coking situation of the lower furnace of the boiler, thereby reducing the NOx emission. The wing wall is longitudinally opened with 4 ventilation slits to blow the secondary air inward. The outer diameter of the water wall pipe at the wing wall is 120.65mm, the center distance is 146.4mm, the pipe gap is 25.4mm, and the outer diameter of the upper and lower pipes on the wing wall is 69.85mm. The reducer pipe connects the two ends. The thick pipes at the four ventilation belts for ventilation are replaced with thin pipes. The gap between the pipes is 76.55mm. The height of the ventilation belt is set to the total length of the wing wall pipe or half of the wing wall. .

[0059] The wing wall is longitudinally opened with 4 ventilation slits to blow the secondary air inward. The outer diameter of the water wall pipe at the wing wall is l...

Embodiment 4

[0071] In this embodiment, the method for reducing NOx emissions from a W-shaped flame boiler is based on Example 1. The W-shaped flame boiler is equipped with four coal mills, and the ratio of bituminous coal to anthracite is 1:1; the first coal mill, For bituminous coal on the third coal mill, the volatile content of a single coal is limited to 20% to 30%. The second and fourth coal mills grind anthracite, that is, there is a coal mill on the front and back walls of pure bituminous coal. The ratio of bituminous coal to anthracite is 1:1, the grinding outlet temperature of the first coal mill and the third coal mill is 118°C, and the grinding outlet temperature of the third coal mill is 109°C.

[0072] Compared with a scheme in which four coal mills evenly burn pure anthracite for combustion, the scheme adopted in this embodiment can effectively improve boiler efficiency, reduce the amount of desuperheating water, and reduce power supply coal consumption and NOx emissions.

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Abstract

The invention relates to a method for reducing W-type flame boiler NOx emission. Fuel burns in a staged combustion manner, the method for reducing W-type flame boiler NOx emission specially comprises that free-burning coal and anthracite in a predetermined proportion are selected, the free-burning coal is employed to react with oxygen to form first stage combustion, wherein the free-burning coal is bituminous coal or a mixture of bituminous coal and meager coal; a high temperature flue gas atmosphere is formed in the first stage, being coerced by high temperature flue gas, the anthracite is ignited to form second stage combustion, the volatile component content of the free-burning coal is higher than of the anthracite, the volatile component content is larger than 25%, and the ratio of the bituminous coal to the anthracite is larger than 1:1; the dry ash-free basis volatile component content of as-fired coal keeps satisfying the formula: 15% < Vdaf < 20 %, the lower heating value of the as-fired coal keeps satisfying the formula: 20 MJ / kg < Qnet, ar < 22.5 MJ / kg, when the bituminous coal, the meager coal and the anthracite burn in a staged manner, Vdaf > 10 %. According to the invention, by employing a staged combustion control strategy, NOx generated by boiler combustion is reduced.

Description

Technical field [0001] The invention relates to a method for reducing NOx emissions from a W-shaped flame boiler. Background technique [0002] The amount of NO produced in coal-fired boilers accounts for more than 90% of the total NOx. NO2 is only formed by partial NO conversion when the high-temperature flue gas is rapidly cooled, and it accounts for 5% to 10% of the total NOx. In the process of pulverized coal combustion, NOx can be divided into three types according to its generation mechanism: thermal NOx (Thermal NOx), fuel NOx (Fuel NOx) and rapid NOx (PromptNOx). [0003] Among the NOx generated by the combustion of pulverized coal, fuel-based NOx is the main one, which accounts for more than 80% to 90% of the total NOx generated. The generation of thermal NOx has a lot to do with the combustion temperature. When the temperature is high enough (> At 1500℃), the thermal NOx can account for 20% of the total NOx. At higher temperatures, the thermal NOx can be more than 30...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F23L9/00F23K1/00F23C5/08F23C7/00F23N3/00F23M5/08
CPCF23C5/08F23C7/00F23K1/00F23L9/00F23M5/08F23N3/00
Inventor 张新
Owner 中国大唐集团科学技术研究总院有限公司
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