1000MW塔式爐低氮燃燒器如何改造？

一、確定改造目標值
（1）在燃用電廠目前運行煤種時，500MW~1000MW負荷時，NOX排放值控制200~150mg/Nm3。該目標值通過脫硝裝置降NOX能力、低氮燃燒器降NOX能力綜合比對所得。
（2）改造后，鍋爐不完全損失、排煙損失無明顯變化。
（3）改造后，鍋爐結焦性、高溫腐蝕性、汽溫汽壓特性等與改造前相當。
1. Determine the target value of transformation
(1) when the coal is currently in operation in the fuel power plant, the NOX emission value is controlled from 200 to 150mg/Nm3 at the load of 500MW~1000MW. The target value was obtained by comprehensive comparison of NOX reduction capacity of denitrifying device and NOX reduction capacity of low nitrogen burner.
(2) after the modification, there is no obvious change in incomplete loss and smoke discharge loss of the boiler.
(3) after the modification, the characteristics of coking, high temperature corrosion and steam temperature and vapor pressure of the boiler are the same as before the modification.
二、1000MW塔式爐低氮燃燒器如何改造？
1.低氮燃燒器改造方案一
（1）在原六層SOFA燃盡風上方新增加三層的SOFA燃盡風。改造后，總的SOFA燃盡風風量占總風量的比率將由原先的23%提高至40%左右。
（2）更換主燃燒器區域全部二次風噴口，縮小二次風通流面積。
（3）更換主燃燒器區域一次風煤粉噴嘴、噴管及彎頭。
2.低氮燃燒器改造方案二
僅在原六層SOFA燃盡風上方新增加三層的SOFA燃盡風，其他燃燒器不改動。
3.改造方案對比分析
（1）方案一：改造工程量大，改造費用較高；
（2）方案二：影響鍋爐燃燒效率，且存在部分安全隱患，詳細分析如下：鍋爐原二次風率為79.16%，燃盡風風率為23%，主燃區二次風率為56.16%，二次風設計速度為60.3m/s。如該造后新增一段燃盡風，風率為17%，而主燃區二次風通流面積不減小，則二次風通流面積增加17/79.16=21.475%。改造后二次風速降為49.64m/s。
1000MW機組塔式鍋爐爐膛橫截面較大，需要較高的二次風速，才能保證火炬的穿透深度和影響深度，才能到達相鄰燃燒器的噴口附近，點燃相鄰的燃燒器，才能有效地促進煤粉的燃燒。二次風速降低，將對爐內流場產生不利影響，一方面不利于煤粉的燃燒，另一方面二次風對一次風的風包粉效果減弱，鍋爐結渣和高溫腐蝕的風險升高。
通過綜合比對，選擇改造方案一。
2. How to transform the low-nitrogen burner of 1000MW tower furnace?
1. Low-nitrogen burner renovation scheme 1
(1) the original six-layer SOFA is a newly added three-layer SOFA. After the renovation, the ratio of the total SOFA exhaust air volume to total air volume will be increased from the original 23% to about 40%.
(2) replace all secondary air vents in the main burner area to reduce the secondary air flow area.
(3) replace the primary air pulverized coal nozzle, nozzle and elbow in the main burner area.
2. Low-nitrogen burner renovation plan ii
Only the original six-layer SOFA has a new three-layer SOFA with no changes in other burners.
3. Comparative analysis of transformation plans
(1) scheme 1: large amount of renovation project and high renovation cost;
(2) scheme 2: it affects the combustion efficiency of the boiler, and there are some safety risks. The detailed analysis is as follows: the primary secondary air rate of the boiler is 79.16%, the burnout wind rate is 23%, the secondary air rate of the main combustion zone is 56.16%, and the secondary air design speed is 60.3m/s. If a new section of exhaust air is added after the construction, the wind rate is 17%, while the area of secondary air flow in the main combustion area does not decrease, the area of secondary air flow increases by 17/79.16=21.475%. After the reconstruction, the secondary wind speed dropped to 49.64m/s.
The cross-section of the furnace of the tower boiler of 1000MW unit is large, so it needs high secondary wind speed to ensure the penetration depth and influence depth of the torch, to reach the vicinity of the nozzle of the adjacent burner, to ignite the adjacent burner, and to effectively promote the combustion of coal powder. The decrease of secondary wind speed will have adverse effects on the flow field in the furnace. On the one hand, it is not conducive to the combustion of coal powder; on the other hand, the secondary wind will weaken the effect of primary wind on the wind packing powder, and the risk of slag formation and high temperature corrosion of the boiler is increased.
Through comprehensive comparison, choose reform plan 1.


三、改造后調試工作
1.合理控制NOX排放值低氮燃燒器改造后，合理控制NOX排放值很重要。NOX控制偏低，則可能影響鍋爐燃燒效率，嚴重時，可能造成嚴重的高溫腐蝕。
通過合理的燃燒控制調整，500MW~1000MW負荷時，可以將NOX排放值控制在既定設計范圍之內：200~150mg/Nm3，既能夠保證機組經濟性基本不受影響，也能消除低氮燃燒器改造后可能存在的安全隱患。
按照這一核心思想，對不同運行工況下，進行燃燒調整；并根據最佳調整效果，對各燃燒自動控制系統進行適配性優化。
2.改造前后效果對比
（1）NOX排放值月平均降低70mg/Nm3；
（2）鍋爐各項燃燒損失基本不變；
（3）因NOX排放較少，每日耗氨量約下降2t/h左右，每噸氨量3000元計算，年度共節約219萬元。
（4）改造后，主再汽溫比原先值偏高2~3益，但是通過調整后，基本不影響機組經濟性。
（5）改造后，鍋爐結焦性、高溫腐蝕、變負荷穩定性等無明顯變化。
Iii. Commissioning after renovation
1. It is important to control NOX emission value reasonably after the modification of the low nitrogen burner. Low NOX control may affect the boiler combustion efficiency, and in severe cases, may cause severe high temperature corrosion.
Through reasonable combustion control adjustment, when 500MW~1000MW is loaded, the NOX emission value can be controlled within the set design range: 200mg /Nm3, which can not only ensure the basic economic efficiency of the unit is not affected, but also eliminate the potential safety risks after the modification of the low-nitrogen burner.
According to this core idea, the combustion adjustment is carried out under different operating conditions. According to the optimal adjustment effect, the adaptive optimization of each combustion automatic control system is carried out.
2. Comparison of effects before and after transformation
(1) the monthly average reduction of NOX emission value was 70mg/Nm3;
(2) the burning loss of the boiler is basically unchanged;
(3) due to low NOX emission, the daily consumption of ammonia decreased by about 2t/h, and the annual consumption of ammonia was calculated at 3,000 yuan per ton, saving a total of 2.19 million yuan.
(4) after the modification, the main steam temperature is 2~3 times higher than the original value, but after the adjustment, the unit economy will not be affected.
(5) after the modification, there is no obvious change in boiler coking, high temperature corrosion, variable load stability, etc.


如果想了解更多關于低氮燃燒器相關知識，請咨詢北京眾誠永源節能環保技術有限公司。
For more information on low nitrogen burners, please consult Beijing chuangwei electromechanical equipment co., LTD.