As a kind of mechanical equipment of gas compression and gas transportation, blower includes blower, blower and compressor. It is widely used in petrochemical, coal, electric power, metallurgy, construction, environmental protection and many other fields. It is one of the necessary equipment for engineering production and application.
Roots blower is a volumetric blower, which is mainly composed of body, wall board and rotor with impeller. Through gear transmission, the rotor rotates in the opposite direction in the body.
Depending on the gap between impeller and impeller, impeller and body, impeller and wall plate, the air inlet chamber and exhaust chamber are basically isolated. With the help of impeller rotation, the accumulated gas in the air inlet chamber is transferred from the air inlet chamber It is pushed to the exhaust chamber without compression to achieve the purpose of blowing.
Roots blower of outline drawing
In the sludge incineration project, the sludge incinerator is a circulating fluidized bed. In order to control the conversion rate of fuel nitrogen to nitrogen oxides in sludge incineration, the primary air and secondary air are divided into primary air and secondary air. Roots blower is selected for primary air supply of circulating fluidized bed. Roots blower is controlled by frequency conversion. Pressure transmitter and flowmeter are set at outlet of Roots blower to collect air volume and blower outlet pressure data in central control room.
Flow chart of sludge incineration
Under the condition of constant motor frequency, the variation curve of Roots blower outlet air volume is shown in Fig. 3.
Roots blower outlet air volume of variation curve
It can be seen from Figure 3 that the outlet air volume of Roots blower is basically constant, stable at about 1500m3 / h, the minimum air volume is 1471 m3 / h, the maximum air volume is 1510 m3 / h, and the maximum difference of air volume is 39 m3 / h, accounting for 2.6% of the average air volume.
Roots blower provides the circulating fluidized bed with a constant air flow, which plays an important role in the stable operation and control of the system.
The variation curve of Roots blower outlet pressure with time is shown in Fig. 4. The average pressure is 11.8 kPa, the minimum pressure is 11.2 kPa, the maximum pressure is 12.2 kPa, and the maximum pressure difference is 1.0 kPa, accounting for 8.5% of the average pressure.
Roots blower of outlet pressure variation curve
During the operation of sludge incineration project, even if the outlet pressure of Roots blower reaches 15kpa, when the motor frequency is 25Hz, the air volume of Roots blower is still around 1500m3 / h.
Roots blower can overcome the influence of the fluctuation of outlet pressure on the flow and realize constant flow air supply at a given frequency. The air volume of Roots blower is regulated by motor frequency. When the motor speed increases, the blower air volume increases linearly.
According to the application and operation regulation characteristics of Roots blower in sludge incineration project, it can be seen that the air volume of Roots blower is related to the motor speed, the increase or decrease of blower outlet pressure does not affect the air volume provided by the blower, and the Roots blower can realize constant flow air supply under constant motor speed; it is easier to realize stable operation and control of sludge incineration by using roots blower to supply air to circulating fluidized bed System.