1、设备简介

1.equipment introduction

某厂SG1025/17.4-M847型锅炉为上海锅炉厂制造亚临界、一次中间再热、自然循环、固态排渣炉，锅炉为∏型布置，采用平衡通风，四角切向燃烧，配四台低速钢球磨中储式制粉系统。设计煤种为贫瘦煤。锅炉50%额定负荷滑压工况下设计过热汽温540，再热汽温515℃。

SG1025/17.4 M847 type boiler at a factory for manufacturing subcritical boiler plant in Shanghai, a reheat, natural circulation, solid-state slag furnace, boiler of ∏ type is decorated, USES the balanced ventilation, tangential firing, with four reservoir type in low speed ball mill coal pulverizing system. Design coal for zhengzhou area lean coal. 50% rated load sliding pressure boiler design superheated steam temperature of 540, under the condition of reheat steam temperature 515 ℃.

主燃烧器一次风及二次风逆时针方向布置，双切圆直径大小为719/?686。三次风顺时针方向布置，与一、二次风方向主轴反偏10度。SOFA燃烧器顺时针方向布置，与一、二次风方向主轴反偏6度。三次风与SOFA风共同起消旋风作用。

The primary and secondary air of the main burner are arranged counterclockwise. 719 /? 686. Three times the wind clockwise direction layout, with one, two times the wind direction of the main axis back 10 degrees. SOFA burner is arranged in a clockwise direction, 6 degrees backward from the main axis in the direction of first and second wind. Three times wind and SOFA wind together play the role of anti - cyclone.

主燃烧器一、二次风喷口与SOFA燃烧器喷口均装有自动垂直摆动装置。一、二次风喷口可上下摆动±30度，摆动机构分为上、下两组。SOFA风喷口还可以以手动方式左右摆动±15度。

2、1#机组150MW低负荷工况下的汽温问题及原因分析

2.Analysis of steam temperature problem and its causes in 150MW low load condition of unit 21

锅炉低氮燃烧器改造后主要存在单套制粉运行时主汽温度、再热汽温度低，但后屏过热器管壁超温，一级减温水量增加的现象。通过试验发现当在150MW时如果投运两套制粉系统，如A、C或B、C制粉系统汽温可以达到536℃～538℃，且后屏不超温，过热器有减温水。当投单套制粉系统，过热汽温最低时达504℃左右，再热汽温低达495℃左右，但是过热器一级减温水量却达到近40t/h，前屏也经常超温。

The main steam temperature and reheat steam temperature of a single set of pulverized powder are low after the modification of the boiler low nitrogen burner. Through the study found that when in 150 mw if put two bearing powder system, such as A, C or B and C pulverizing system steam temperature can reach 536 ℃ ~ 538 ℃, and the screen is not overtemperature, superheater with warm water. When single bearing powder system, superheated steam temperature when a minimum of 504 ℃ or so, low reheat steam temperature of 495 ℃ or so, but the superheater level of desuperheating water flow to nearly 40 t/h, front panel also often overtemperature.

分析单套制粉系统运行过、再热汽温偏低原因为：

The reasons for the low reheat steam temperature of the single set pulverized powder system are as follows:

(1)当投运两台磨时，燃烧器四角能够两两相对投运三次风，作为反切消旋功能的三次风流场相对均匀，炉膛出口烟气流场偏差较小，屏底超温较好。

(1) when the operation of two grinding, the corners of the burner to three times the wind two relative was put into operation, the methods of three wind field despun function is relatively uniform, furnace exit deviation is small, smoke flow in the bottom of the screen overtemperature is better.

(2)当投运单台磨时，燃烧器四角只能够投运一个对角三次风而无法形成有效的消旋流场，再者对角三次风的气固两相流速可能不均匀而有可能导致流场的紊乱，使得炉膛出口烟气流场偏差增加，引发屏底超温，过热器减温水大量增加，屏后烟温降低，限制了过热汽温及再热汽温增加。

(2) when cast waybill grinding machine, three times in the corners of the burner can only put a diagonal wind to form effective despun flow field, moreover diagonal three times the wind of the gas-solid two phase flow rate may be uneven and could lead to disorder, the flow field in the furnace exit deviation of smoke flow in increasing, lead to the bottom of the screen overtemperature, superheater reduction with warm water, screen after smoking temperature is reduced, limits the superheated steam temperature and reheat steam temperature increase.

(3)相对于投运两台磨，单台磨投运时燃烬区煤粉浓度低于两台磨投运时的工况，屏底烟气温度也相应较低。

(3) compared with the two mills, the coal powder concentration in the embers area in the single mill is lower than that in the two mills, and the flue gas temperature at the bottom of the screen is lower.

3、治理方案及效果

3. Governance scheme and effect

针对低负荷单套制粉系统主、再热汽温偏低问题原因，提出以下治理措施：

In order to solve the problem of low main and reheat steam temperature of low-load single set pulverized powder system, the following measures are proposed:

(1)提高炉膛送风量，可提高烟气流量。

(1) to increase the air flow in the furnace can increase the smoke flow.

(2)调整SOFA风左右摆角，中、下层SOFA风已经调成与一次风及二次风一致，均为逆时针方向布置，上层SOFA风与一次风及二次风反切。配合主燃烧器消旋二次风及其它二次风比例以控制炉膛出口烟气温度及烟气量的偏差，控制屏过金属温度两侧无偏差时尽量减少减温水量提高汽温。

(2) adjust the left and right Angle of SOFA wind, and the middle and lower SOFA wind has been adjusted to be consistent with primary and secondary wind, both of which are arranged counterclockwise. The upper SOFA wind is opposite to primary and secondary wind. Cooperate with the main burner despun secondary air and other secondary air ratio of air to control the furnace exit flue gas temperature and smoke deviation, control panel metal temperature without deviation on both sides to minimize desuperheating water flow to improve the steam temperature.

(3)在以上基础上汽温仍低时，采用调节主燃烧器摆角向上;适当启动部分D层燃烧器;减少磨机再循环率，提高三次风量;尽量提高C、D层给粉机转速，降低A或B层给粉机转速等方式亦可提高汽温。

(3) when the temperature of the above foundation is still low, the swing Angle of the main burner is adjusted upwards; Properly start part D layer burner; Reduce the recirculation rate of the mill and increase the air volume three times. The steam temperature can be increased by increasing the speed of layer C and layer D feeder as much as possible, and decreasing the speed of layer A or layer B feeder.