Project introduction (characteristics): Zhangjiang Hi-Tech Thermal Power Co., Ltd. newly launched three 20T heavy oil-fired boilers. Due to the severe environmental issues in China and the convening of the World Expo, the Shanghai government has stricter control over SO2 emission standards. Therefore, Zhangjiang Gaoke Thermal Power Co., Ltd. uses an efficient desulfurization system and a boiler. The desulfurization system uses magnesium oxide desulfurization.
Project solution (characteristics):
The desulphurization system is desulfurization by the magnesium oxide method. One furnace and one tower, the flue gas system, the absorption system, and the demister are relatively independent for each furnace, and others are public systems. After the flue gas from the boiler passes through the booster fan, it is introduced into the lower part of the absorber before the bypass flue. The SO2 in the flue gas is absorbed by the fine droplets sprayed downward by the spray layer and flows down to the slurry region at the bottom of the absorption tower during the flow of the flue gas from bottom to top, and further reacts with the desulfurization agent to generate sulfurous acid. Magnesium MgSO 3 , the slurry after desulfurization enters the slurry circulation tank through the water seal pool and the trench, and the air blown by the oxidation fan oxidizes magnesium sulfite to magnesium sulfate MgSO 4 in the tank. Most of the SO2 that has been scrubbed away and the small amount of fly ash that has been washed upwards passes through the spray layer and passes through the demister. After being removed from most of the carried droplets, it returns to the mother flue and is discharged through the chimney. By continuously adding the desulfurizing agent and the rinsing water of the demister, the SO2 in the flue gas is continuously removed; through the quantitative discharge, the magnesium sulfate solution, which is the reaction product of the absorption tower, is constantly discharged outwards, and the entire absorption system is maintained internally. Water balance and material balance.
This control system adopts PLC control and has a high degree of automation. Each boiler and desulfurization tower is equipped with a booster fan, so that the boiler outlet flue gas can smoothly pass through the desulfurization tower to be purified and discharged to ensure the stable and safe operation of the boiler. The booster fan adopts variable frequency control. The feedback signal is the pressure value at the outlet of the boiler. The fan speed is adjusted by keeping the pressure at the bypass flue. The fan speed is adjusted by frequency conversion, and the fan inlet manual adjustment door can be Adjusting the air volume and wind speed at the inlet of the fan can further ensure the stability of the boiler operation. The desulfurizer flow rate from the slurry preparation system is regulated by a desulfurizer flow control valve. If the pH control procedure is not automatic, the opening of the flow control valve is determined by its manually set value. The actual opening determines the actual desulfurizer. flow. If the pH control program is automatically cast, the manual setting of the desulfurizer flow control valve will not work and the opening of the control valve will be automatically determined by the PLC program. Within 0.2). When the demister auto program is selected, the opening and closing of the solenoid valve operates and stops according to the program set in the PLC in advance. For specific settings, refer to the debugging data. General can be set as flushing time 90 seconds, valve interval time 60 seconds, interval time 60 seconds, and these data can be modified on the host computer to ensure optimal operation.
Acceptance of the project: The desulfurization system is energy-saving, environmentally-friendly, and highly efficient. It passed the acceptance of the Shanghai Environmental Protection Bureau on October 15, 2009.