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CN-122015122-A - Adjusting method and device for reducing carbon content of fly ash of W-flame boiler

CN122015122ACN 122015122 ACN122015122 ACN 122015122ACN-122015122-A

Abstract

The invention discloses an adjusting method and device for reducing the carbon content of fly ash of a W flame boiler, which comprises the steps of testing the volatile matters of the coal entering the boiler, controlling the volatile matters of the coal entering the boiler, adjusting the opening of a baffle plate, an air door and a powder pipe shrinkage hole of a separator of a coal mill, adjusting the primary air temperature and the fineness of the coal powder of each layer of burner and the uniformity of the primary air to be within a required range, adjusting the operating oxygen content of the boiler, the opening of a secondary air door and the opening of a secondary air box of a single burner, controlling the level of the oxygen entering the boiler and the distribution of the oxygen entering the boiler, adjusting the opening of the exhaust air of a main burner of the boiler, reasonably distributing the proportion of the primary air and the exhaust air, not only stabilizing ignition but also avoiding excessive air shortage, reasonably setting the proportion of the upper air door and the lower air door, namely partially opening the upper air door, greatly opening the lower air door and fully opening the lower air door, reasonably supplying the lower air door for the combustion in the later stage of the combustion, providing proper down-flushing depth for the primary air and greatly supplementing the lower air in order to facilitate the combustion of the coal powder.

Inventors

  • YANG ZHONGCAN
  • ZHANG XILAI
  • LI YAN
  • GUO YANGZHOU
  • LI XINGZHI
  • SUN JUN
  • ZHOU GUANGQIN
  • TU JINGYI
  • LI RENYI

Assignees

  • 西安热工研究院有限公司

Dates

Publication Date
20260512
Application Date
20260304

Claims (10)

  1. 1. An adjusting method for reducing the carbon content of fly ash of a W-flame boiler is characterized by comprising the following steps: 1) Testing the quality of the coal in the furnace, and controlling the volatile component V daf of the coal in the furnace to be more than or equal to 10-12%; 2) Adjusting the baffle or the rotating speed of a separator of the coal mill, and controlling the fineness R 90 of the coal powder to be 3-8%; 3) The uniformity of the primary air speed of the coal mill is regulated, and the deviation of the primary air speed is controlled within +/-5%; 4) Adjusting the outlet air temperature of the coal mill to be 70-120 ℃; 5) When the boiler load is above 80% ECR, adjusting the running oxygen amount of the boiler to 4.2-4.5%, and adjusting the oxygen amount distribution in the width direction of the boiler; 6) Adjusting a ventilation air door of the main burner, wherein the ventilation air door is arranged according to different volatile component requirements of the coal and 30-70%; 7) The opening degree of an arch secondary air gate around an arch primary air nozzle is adjusted to be 30-50%, oxygen required in the initial stage of ignition of pulverized coal airflow is supplemented, and the rigidity and the downward injection depth of primary air are ensured; 8) And adjusting the opening of the tertiary air door under the arch to 70-100%, and supplementing oxygen required by later burnout.
  2. 2. The method for adjusting fly ash carbon content of a W flame boiler according to claim 1, wherein in the step 1), volatile matters in coal are measured according to GB/T212-2008 method for industrial analysis of coal.
  3. 3. The method for reducing the carbon content in fly ash of a W-flame boiler according to claim 1, wherein in the step 1), if the volatile components of the coal to be fed into the furnace are low, the coal to be fed into the furnace is premixed and blended with the high-volatile component coal, and then the coal to be fed into the furnace is ground and fed into the furnace.
  4. 4. The method according to claim 1, wherein in the step 2), the pulverized coal fineness R 90 is controlled to be 6-8% for a lean coal-fired boiler and the pulverized coal fineness R 90 is controlled to be 3-5% for an anthracite-fired boiler.
  5. 5. The method according to claim 1, wherein in step 3), the primary wind speed measurement and adjustment is performed according to the power station coal mill and pulverizing system performance test (DL/T467-2019).
  6. 6. The method for reducing the carbon content in fly ash of a W flame boiler according to claim 1, wherein in the step 4), the primary air temperature is controlled to be 110-120 ℃ when lean coal and anthracite coal are burned in the boiler, and the primary air temperature is controlled to be 70 ℃ when bituminous coal is burned.
  7. 7. The method for adjusting the fly ash carbon content of the W flame boiler according to claim 1, wherein in the step 5), the adjustment of the uniformity of the oxygen amount is realized by adjusting the air volume distribution of the air inlet of a single burner or the left, middle and right three bellows by taking the oxygen amount distribution from a denitration inlet as a reference.
  8. 8. The method for reducing fly ash carbon content of a W flame boiler according to claim 1, wherein in the step 6), when the boiler burns lean coal and anthracite, the exhaust gas damper is controlled to be 50-70%, and when the boiler burns bituminous coal, the exhaust gas damper is controlled to be 30-50%.
  9. 9. The method for adjusting the fly ash carbon content of the W flame boiler according to claim 1, wherein in the step 8), the opening of the tertiary air gate under the arch is adjusted, the opening of the secondary air box is not lower than 70% when the boiler is subjected to an ECR load of 80%, and the carbon content of the fly ash of the boiler is reduced to be less than or equal to 3.0% after the adjustment.
  10. 10. An adjusting device for reducing the carbon content of fly ash of a W-flame boiler, which is characterized by comprising: the coal quality testing unit tests the coal quality of the furnace, and controls the volatile component V daf of the coal to be more than or equal to 10-12%; the separator adjusting unit is used for adjusting the baffle plate or the rotating speed of the separator of the coal mill and controlling the fineness of the coal powder to be 3-8%; the primary air temperature adjusting unit is used for adjusting the outlet air temperature of the coal mill and controlling the primary air temperature of each layer of burner to be 70-120 ℃; the total air quantity adjusting unit is used for adjusting the running oxygen quantity of the boiler to be 4.2-4.5% above the boiler load of 80% ECR; The primary air speed adjusting unit is used for adjusting a primary air exhaust air door of the main burner to be 30-70%; A secondary air adjusting unit for adjusting the opening of the secondary air door on the arch by 30-50%; and the tertiary air regulating unit is used for controlling the opening degree of the under-arch tertiary air door to be 70-100%.

Description

Adjusting method and device for reducing carbon content of fly ash of W-flame boiler Technical Field The invention belongs to the field of economic operation and energy conservation and consumption reduction of power station boilers, and particularly relates to an adjusting method and device for reducing the carbon content of fly ash of a W-flame boiler. Background Anthracite coal has a predicted reserve of 4742.43 hundred million tons and accounts for about 10 percent of the total coal resources in China, is mainly distributed in Shanxi provinces, henan provinces, guizhou provinces, shaanxi provinces, ningxia provinces and the like, has a yield of about 4 hundred million tons/year, and is parallel to bituminous coal and lignite coal to become one of important thermal power coal in China. The anthracite has the characteristics of high fixed carbon content and high heat value, but low volatile matter, and the dry ash-free base volatile matter V daf is generally 6.5-12.0%, so that the anthracite has high ignition point, long combustion stroke and low burnout rate, and when the anthracite is used for burning a pulverized coal boiler of a power station, most of the anthracite adopts a W flame combustion mode except a small amount of the anthracite adopts a four-corner tangential mode. W flame boiler, early for the United states FW, british Babcock and other company introduction technology, at present mainly by the eastern, harbin boiler factory design and manufacture of China. The boiler furnace consists of a lower arched firing furnace and an upper radiation furnace, wherein the tops of the front and rear protruding parts of the firing furnace form a furnace arch, a coal powder nozzle and a secondary air nozzle are downwards ejected from the furnace arch, high-temperature flue gas of W-shaped flame formed in the firing furnace below the furnace arch just flows back to the root of coal powder airflow, the firing process of coal powder is very beneficial, when the fired coal powder airflow downwards flows and expands, after meeting with tertiary air at the lower part of the firing furnace, the fire flows upwards at 180-degree turning, W-shaped flame is formed, and high-temperature flue gas generated by combustion enters the upper radiation furnace. A large number of fire protection belts are laid on the water cooling walls around the furnace arch burner and on the two side walls below the furnace arch burner to form high temperature of a fire area, which is beneficial to fire. Practical experience at home and abroad shows that the W-flame boiler is provided with double-inlet double-tapping ball milling, the pulverized coal is thinner, the residence time in the furnace is long, and the W-flame boiler is effective for burning low-volatility coal types. However, in recent years, with the rapid development of new energy installation in China, a smokeless coal power station for burning faces the situation of double reduction of power generation capacity and electricity price, the operation of the power plant is difficult, a large amount of coal with lower price and heat value is required to be burned, the coal burning characteristic is reduced, the primary air quantity of a coal mill is required to be maintained to ensure output, the pulverized coal is thickened, the burning-out difficulty is caused, the carbon content of fly ash is greatly increased from about 3% to more than 5%, the boiler efficiency is reduced by 1%, the power generation coal consumption is increased by more than 3g/kWh under the condition of higher ash content, and the economic index of the unit and the operation economy of the power plant are seriously affected. In order to reduce the combustion economy of the W-type boiler and improve the operation performance of a power plant, the power plant generally adopts the modes of increasing the loading capacity of steel balls, optimizing the diameter proportion of the steel balls, replacing the lining plates of a coal mill and the like to strive for reducing the carbon content of fly ash by reducing the fineness of coal dust, but the effect is often poor. In order to improve the combustion condition of the boiler and improve the adaptability to high ash, low heat value and low volatile coal, a new method for reducing the carbon content of the fly ash of the boiler is urgently needed to be developed. Disclosure of Invention The invention provides an adjusting method and device for reducing the carbon content of fly ash of a W flame boiler aiming at the problems. The invention is helpful for solving the problems of increased carbon content of fly ash and the like caused by poor coal quality, unreasonable coal blending mode, improper operation adjustment and the like of the power station boiler. In order to achieve the above purpose, the present invention adopts the following technical scheme: an adjusting method for reducing the carbon content of fly ash of a W flame boiler comprises the following steps