Method and device for multi-grade mixed combustion of double fuels at cyclone state

A combustion device and dual-fuel technology, which is applied in the direction of gaseous fuel and powder fuel combustion, combustion equipment, lighting and heating equipment, etc., can solve the problem of unsatisfactory pulverized coal burnout effect, high NOx content in flue gas, and coal type adaptation Insufficient compatibility and other issues, to achieve the effects of easy access, reduced flue gas NOx emission concentration, and reasonable distribution

Inactive Publication Date: 2013-08-21
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problems of small and medium-sized industrial pulverized coal boilers, such as poor coal adaptability, poor flame stability, unsatisfactory pulverized coal bur...

Method used

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  • Method and device for multi-grade mixed combustion of double fuels at cyclone state
  • Method and device for multi-grade mixed combustion of double fuels at cyclone state
  • Method and device for multi-grade mixed combustion of double fuels at cyclone state

Examples

Experimental program
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specific Embodiment 1

[0040] The auxiliary fuel flow sprayed forward by the central nozzle (4) is the second-stage auxiliary fuel stream (11), and the auxiliary fuel in the second-stage auxiliary fuel stream (11) is the same as that in the first-stage auxiliary fuel jet (3). The components are the same, and they are injected from the center of the nozzle to the depth of the burner flame along the axis. When gaseous fuel is used as auxiliary fuel, the injection velocity of the second-stage auxiliary fuel ranges from 35 to 50m / s; when high-quality solid fuel is used as auxiliary fuel , the range of injection velocity is 25~35m / s. When the high-speed stream of the central auxiliary fuel moves forward rapidly in the center of the burner flame, the outer side of the stream contacts the high-temperature flue gas in the recirculation zone of the burner, and the fuel on the outer side of the high-speed stream is ignited to form a long strip-shaped torch, which can further stabilize the coal When most o...

specific Embodiment 2

[0044] The auxiliary fuel supply method of this embodiment is suitable for gas auxiliary fuel, especially methane (CH 4 ) other than alkanes as the main components of gas fuels (such as liquefied petroleum gas, etc.) and gas fuels with methane as the main component and higher content of other alkanes (such as natural gas, etc.) are more effective. The composition of the first-stage and second-stage gas-assisted fuel is the same, and the supply ranges are 2-10% and 10-20% of the total calorific value of the burner fuel, respectively.

[0045] Specific implementation example three

specific Embodiment 3

[0047] When the central high-speed stream (11) and the outer ring high-speed stream (12) are injected into the depth of the burner flame, the second-stage auxiliary fuel on the outer surface of the high-speed stream (11) and (12) burns to form an inner and outer The distributed strip-shaped long torch can ensure good stability of the pulverized coal flame even when the load is low and the pulverized coal airflow presents general fluctuations.

[0048] This implementation example is applicable to the situation where gaseous fuel is used as auxiliary fuel, such as: coke oven gas, producer gas, natural gas, liquefied petroleum gas, blast furnace gas, converter gas, and combustible gas by-products produced in chemical industries. The composition of the first-stage and second-stage gas auxiliary fuels is the same, and the supply ranges are 2-10% and 10-25% of the total calorific value of the burner fuel, respectively. The auxiliary fuel provided by the outer ring high-speed stream (...

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Abstract

The invention provides a method and a device for multi-grade mixed combustion of double fuels at a cyclone state. On the basis of graded air supplying cyclone combustion, multi-grade mixed combustion of an auxiliary fuel and coal powder is realized and NOx in smoke is reduced: in a process of conveying the coal powder to a combustor, the auxiliary fuel is divided into two grades according to a ratio; a first-grade auxiliary fuel is led into the front end of the combustor to be subjected to the mixed combustion with the coal powder of a concentrated phase, so as to achieve effects of supporting combustion and stabilizing flame of the coal powder; a second-grade auxiliary fuel is conveyed to the tail end of a primary combustion region by a high-speed and small-stream manner to be mixed and combusted with high-temperature smoke at the tail end of the primary combustion region and a secondary combustion region, so as to reduce the NOx generated in the primary combustion region; and proportional control of combustion-supporting air which is fed by grades is matched to guarantee the sufficient combustion of the coal powder and the auxiliary fuels. The method disclosed by the invention can be used for modifying a coal powder cyclone combustor to meet the requirements of the mixed combustion, does not influence the structure and the performance of the combustor and is low in modification cost; and the method can also be used for designing a novel mixed combustion cyclone combustor and the coal powder can be independently combusted when necessary.

Description

technical field [0001] The invention relates to the field of combustion equipment, in particular to a method and device for reducing the NOx of coal-fired flue gas by dual-fuel multi-stage mixed combustion in a swirling flow state. Background technique [0002] NOx is an important pollutant in the atmosphere. It not only forms acid rain with severe corrosion, but also forms acid fog, which seriously affects people's health. Therefore, countries all over the world have formulated strict emission standards. In modern life and industrial production, coal combustion is one of the main sources of NOx, and some standards have limited the NOx emission index of pulverized coal boiler flue gas to 200mg / Nm 3 the following. [0003] There are two main ways to control NOx by pulverized coal combustion, namely: the use of flue gas denitrification technology and low-nitrogen combustion technology. Although the flue gas denitrification technology can reduce the NOx content by more than 7...

Claims

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Application Information

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IPC IPC(8): F23C1/12F23C7/00
Inventor 张宗旺秦雪刚董博旭侯星慧
Owner UNIV OF SCI & TECH BEIJING
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