Publish Time: 2022-09-02 Origin: Site
The blast furnace centrifugal fan is mainly composed of a static part and a rotating part. The static part consists of the casing, the air inlet pipe, the bearing, the sealing device, the fan expander, the return device and the air outlet pipe. The rotating part consists of the rotor and the impeller mounted on the main shaft of the rotor, the thrust plate, the balance wheel, etc.
The function of each component is the same as that of the axial flow blower, but the stage structure of the centrifugal blower is different. It is composed of a centrifugal impeller and a static element (such as a vaneless and vane diffuser, a recirculator), and the intermediate stage static element. The function is the same as the intermediate deflector of the axial flow blower, but the gas is sucked and output under the action of centrifugal force.
The blast furnace centrifugal fan has the advantages of large single-stage compression ratio, complete machine, few stages, flat characteristic curve, relatively stable efficiency under different working conditions, and less dust pollution and wear on blades.
1. Air volume and air pressure.
The air volume and air pressure of the blower are two important basic parameters in the fan selection. The pressure of the blower depends on the top pressure of the blast furnace. The large blast furnace will gradually be changed to a high-pressure furnace top, and its pressure is 01MPa-0.25MPa (gauge pressure); it also determines the resistance in the furnace and the loss of the pipeline; the pressure of the blast furnace fan should also ensure the blast furnace. It can also be operated safely when the situation deteriorates.
Due to changes in climatic conditions and fluctuations in the process operation itself, the required air volume and air pressure also need to change accordingly, so the blower cannot be fixed at one operating point, but in an operating operating area. When selecting a blower, The operating conditions of the blower should be included as far as possible within the effective use range of the blower characteristic curve.
2. Fan efficiency
In the current brutal market competition of iron and steel products, all iron and steel enterprises are looking for measures to reduce production costs. In addition to using blast furnace coal injection to reduce coke ratio, improve smelting coefficient and enhance production capacity, improve the efficiency of blast furnace air supply system. one of the important measures.
The efficiency of the blower determines the economy of the normal operation of the blower. Therefore, a blower with high rated (design) efficiency and a wide high-efficiency area should be selected as much as possible, so that the blower can operate economically for as long as possible throughout the year.
3. Increase the blast furnace output when the blast furnace equipment conditions have been determined.
In order to achieve high yield, high quality and low consumption in blast furnace production, when the conditions of blast furnace equipment have been determined, it is necessary to start from two aspects of blast furnace operation and raw material quality. Blast furnace operation requires blast furnace to strengthen smelting, and high-pressure operation is a measure in strengthening smelting , that is, to increase the furnace top pressure, reduce the pressure difference, and promote the forward running of the blast furnace, which is an important measure to ensure the forward running of the large blast furnace under high-strength smelting conditions.
High-pressure operation requires the blower to have a pressure that meets the high-pressure operation, so as to ensure that sufficient air volume can be supplied to the blast furnace under high-pressure operation.
When the blower is replaced, it is required that the outlet air pressures of the two blowers be switched when they are very close or equal. At this time, the use of constant air pressure operation will make the machine more stable and fast when reversing.