The CO sensor was introduced by boiler manufacturers and piloted a small range. However, due to the high temperature in the furnace and the constraints such as the sensor performance, it has not been included in the reference indicator of the boiler combustion adjustment. With the rapid progress of China's manufacturing process in recent years, it is possible to install the CO sensor and serve as an effective balance and efficient combustion, low nitrogen emissions, and high temperature corrosion/focus. The following discusses the influencing factors affecting the CO concentration according to the on -site test data.

1. The influence of the openness of the wind door

During the SOFA wind door opening adjustment test, the#1 unit runs at 600MW load conditions, and adjusts the Sofa wind door to 30%, 20%, and 10%. , Specifically as shown in Table 1.

Table 1 Different Sofa wind door opens at the furnace CO concentration

It can be seen that when the opening degree of the SOFA wind door is above 20%, it has a great impact on the concentration of the furnace CO, but its impact on NO X is very limited; when the SOFA wind door opening is 10%, the concentration of the furnace CO can be reduced to less than 20000 ppm, indicating that it means Reducing the exhaustion rate is conducive to alleviating high temperature corrosion. In addition, when the opening degree of the Sofa wind door is greater than 20%, the reduction of its opening degree on the NO X concentration of the Nitrite entry is less. Therefore, in the high load section, the opening degree of the Sofa wind door is kept between 10%-30%, which can reduce the furnace CO concentration, but also ensure that the NO X content of the denitration inlet is within the controllable range.

Second, the impact of air volume adjustment

During the period of stable load above 600MW and when the CO content of the tail is too high, the variable air volume test is performed. The test parameters are shown in Table 2, and the main parameter curve before and after the air volume adjustment is shown in Figure 1.

Table 2 Test the test parameters under high CO work conditions

620mW In stable working conditions, the total air volume is increased by 50t/h. If calculated at the initial value of 4000 ppm, at this time, the loss of smoke heat increased by 0.16%, and the chemical incomplete burning loss decreased by 1.25%.

Under 630MW stable working conditions, increase the total air volume of 80t/h, and the rear CO is reduced from 1000ppm to 450ppm. At this time, the loss of smoke was increased by 0.11%, and the chemical incomplete burning loss decreased by 0.21%.

In addition, for each reduction of 1000 ppm, the Q 3 decreases by 0.3459%, and the reduction of coal consumption is approximately converted to 1.11g/kWh. Comparing the impact of the efficiency of boilers and increased electricity consumption on the economy alone, the calculation value is shown in Table 3.

Table 3 Economic Comparison Data

3. O2-CO collaborative control logic and investment strategy

Before investing the CO control circuit, the oxygen amount must be automatically invested. The output value of the CO controller is superimposed to the set value of the oxygen volume. The corresponding relationship between the CO setting value is shown in Table 4.

Table 4 Load and CO set value corresponding relationship

In addition, the sensor sensitivity of the CO sensor is 1%and the range is 4000 ppm. The control loop setting value dead area is tentatively set to ± 100ppm. In order to prevent the random interference in the CO measurement circuit, the 30S signal filtering was set, and the CO measurement value was lower than the 50ppm point as a bad point. When the measured value of the CO on both sides was defined as a bad point, the CO automatic control loop exited exit Essence

By increasing the CO measuring point, the parameter monitoring of the boiler operation is added. On the basis of taking into account the efficiency of boiler efficiency, denitration control, and parameter deviation, the operator can control the incomplete local combustion, reduce the speed of high temperature corrosion, improve the efficiency of boiler efficiency