CN116906128A - A shaft-end reverse gas sealing device for a blast furnace gas TRT turbine unit - Google Patents

Abstract

The invention discloses a shaft end reverse air seal device of a blast furnace gas TRT turbine unit, which comprises a rotor main shaft and stator blades, wherein the rotor main shaft and the stator blades are arranged in a machine shell, two sides of each stator blade respectively form a gas inlet channel and a gas outlet channel, small axial flow fans are respectively sleeved on the positions of shaft end air seals at two ends of the rotor main shaft, the axial flow fans are fixed on the rotor main shaft through shaft sleeves, the axial flow fans and the main shaft are concentric, after the rotor rotates, the axial flow fans are driven to rotate, the axial flow fans generate air flow opposite to the shaft seal discharge, the air pressure generated by the reverse air flow is used for preventing gas in a cylinder from leaking out of the gas through a shaft end air gap, a balance pipe is arranged between two side walls of the machine shell at the outer side of the axial flow fans, a gas balance valve is arranged on the balance pipe, and the upper part of the balance pipe is communicated with the middle part of the machine shell.

Description

A shaft-end reverse gas sealing device for a blast furnace gas TRT turbine unit

Technical field

The invention relates to a shaft end reverse gas sealing device of a blast furnace gas TRT turbine unit.

Background technique

In the blast furnace TRT turbine unit, there are gaps between the dynamic and static parts of the rotor and the casing, causing high-pressure gas to leak and overflow through the shaft end gap, causing safety hazards and causing energy waste. In order to prevent gas leakage at the shaft end, multi-stage gas seals and carbon ring seals are installed at the shaft end. The gas seal is depressurized and the carbon ring is blocked to reduce gas leakage; however, in actual applications, due to operating wear, the installation Due to errors and other reasons, gas leakage at the shaft end cannot be completely eliminated, and sometimes serious gas overflow and leakage occur, seriously affecting the safety of equipment and personnel.

Search related patents and literature searches for the sealing form and effect of shaft end air seals, and perform comparative analysis:

Xi'an Thermal Engineering Research Institute Co., Ltd. applied for a patent for "A shaft end sealing device and method for an electromagnetic constrained carbon dioxide turbine". It uses the shaft end sealing device and method of an electromagnetic constrained carbon dioxide turbine to generate a strong electric field between the sealing poles. The ion flow forms a concentrated magnetic field inside the sealed chamber to achieve the sealing effect. This sealing form is suitable for sealing of inert gases; however, no relevant patents have been found for sealing of flammable and explosive gases such as coal gas; it also shows that the application of non-structural flexible sealing forms in shaft end seals has practical effects. However, there is no patented technology application using the reverse sealing form of axial flow fans.

Retrieve related papers. The paper "Research on Equivalent Dynamics Analysis Method of Hydrodynamic Fingertip Seal" written by Li Mengchen of Xi'an University of Technology, in which it is deduced that non-contact seals are suitable for sealing occasions with high requirements on rotation speed and working life. , but after years of development, due to the complexity of its sealing structure and working conditions, research is still very lacking, especially in China, where such research is still blank.

Contents of the invention

The object of the present invention is to provide a shaft-end reverse air sealing device for a blast furnace gas TRT turbine unit, which can effectively prevent airflow from overflowing and achieve the purpose of sealing.

The technical solution adopted by the present invention is a shaft end reverse gas sealing device of a blast furnace gas TRT turbine unit, which includes a rotor main shaft and a stator blade installed in the casing. Both sides of the stator blade form an inlet gas channel and an outlet respectively. The gas channel is equipped with small axial flow fans at the shaft end air seals at both ends of the rotor main shaft. The axial flow fans are fixed on the rotor main shaft through shaft sleeves. The axial flow fans are concentric with the main shaft. When the rotor After rotation, the axial flow fan is driven to rotate. The axial flow fan generates an air flow opposite to that discharged from the shaft seal. The pressure generated by the reverse air flow is used to prevent the gas in the cylinder from leaking outward through the air gap at the shaft end. On the outside of the axial flow fan A balance pipe is communicated between the two side walls of the casing, and a gas balance valve is installed on the balance pipe. The upper part of the balance pipe is connected with the middle part of the casing. Gas is introduced through the balance pipe, and the introduced gas is controlled by the balance valve. Balance pipe pressure, the balance pipe pressure is controlled at atmospheric pressure or slightly positive pressure.

Modify the original shaft-end steam seal device of the TRT unit, change the structure of the rotor steam seal, remove part of the original comb-tooth gas seal, and install blades along the rotor axial direction at the removed part. A full circle of annular blades forms a Set axial flow fan, the fan is fixed on the original rotor through the shaft sleeve. When the rotor rotates, the axial flow fan is driven to rotate. The air flow generated by the blades of the axial flow fan is in the opposite direction to the air flow leaked from the cylinder. The reverse air flow drives the leaked air flow and prevents The airflow overflows to achieve sealing purpose.

In order to ensure continuous flow of the reverse secret fan and prevent external air from being sucked in, gas is introduced through the gas balance pipe on the outside of the reverse fan. The introduced gas controls the pressure of the balance pipe through the regulating valve. The pressure of the balance pipe is controlled at atmospheric pressure or micro. Positive pressure state.

working principle:

1. Use the reverse pressure difference method to prevent gas from overflowing. The fan impeller rotates during work, driving the shaft-end sealed axial flow fan to rotate, sealing the air pressure generated by the axial flow fan during rotation, pushing the gas leaking through the shaft gap in the opposite direction, and preventing the working gas from leaking out through the shaft end gap. In practical applications, according to the pressure of the leaking gas, fan blades with appropriate angles and stages can be installed to meet the needs of different pressures and effectively prevent high-pressure gas from leaking.

2. While the reverse fan prevents gas leakage, it will also suck in outside air. In order to prevent outside air from being sucked in, maintain the air flow of the sealed axial flow fan and control the inlet pressure of the axial flow fan, reverse the axial flow fan at the shaft end. At the inlet, low-pressure gas is introduced, and the introduced gas is led from the discharge side (low-pressure side) of the turbine through the balance pipe; the low-pressure gas introduced into the sealed fan then controls the inlet pressure of the reverse axial flow fan through the regulating valve to ensure axial flow The air pressure at the fan inlet is stable; during operation, the air pressure at the axial flow fan inlet is controlled to a negative pressure of -100 to -1000Pa. This ensures that under a slightly negative pressure state, the gas on the low-pressure side of the axial flow fan does not leak and a large amount of outside air does not enter the sealed system. . The regulating valve controls the pressure of the suction chamber, thereby regulating the gas leakage effect. It is adjustable under different working conditions or after the equipment clearance is worn. At the same time, it can ensure that the axial flow fan can meet the minimum flow requirements and prevent the blades of the reverse axial flow fan from surging.

In order to maintain a slight negative pressure state and prevent outside air from entering the shaft seal system, the original nitrogen seal is still retained at the outermost part of the shaft end. The nitrogen pressure prevents the balance pipe gas from leaking and prevents external air from overflowing.

Description of the drawings

Figure 1 is a schematic front view of the structure of the present invention.

Implementation

A shaft-end reverse gas sealing device for a blast furnace gas TRT turbine unit, as shown in Figure 1, includes a rotor main shaft 8 and stationary blades 10 installed in the casing 3. The rotor main shaft 8 is provided with moving blades 9. Both sides of the stator blade 10 form a gas inlet channel and a gas outlet channel respectively. Main shaft air seals 7 are respectively provided on both sides of the rotor main shaft 8. Reverse sealing covers 4 connected to nitrogen pipes 6 are respectively provided in the casing 3 at the outer periphery of the main shaft air seal 7. The shaft end gas seals at both ends of the rotor main shaft 8 are Small axial flow fans 5 are respectively installed on the sealing parts. The axial flow fans 5 are fixed on the rotor main shaft 8 through the bushing. The axial flow fans 5 and the rotor main shaft 8 are concentric. When the rotor main shaft 8 rotates, The axial flow fan 5 is driven to rotate. The axial flow fan 5 is located in the center hole of the reverse seal cover 4. The axial flow fan 5 generates air flow opposite to that discharged by the shaft seal, and uses the pressure generated by the reverse air flow to prevent the gas in the cylinder from passing through. The air gap at the shaft end leaks gas to the outside. A balance pipe 1 is communicated between the reverse sealing cover 4 outside the axial flow fan 5 and the two side walls of the casing 3. The balance pipe 1 is located in the casing 3 Externally, a gas balance valve 2 is provided on the balance pipe 1. The upper part of the balance pipe 1 is connected with the middle part of the casing 3. Gas is introduced through the balance pipe 1. The introduced gas controls the pressure of the balance pipe through the balance valve 2. The balance pipe 1 The pressure is controlled at atmospheric pressure or slightly positive pressure.

Claims (1)

1. A shaft-end reverse gas sealing device for a blast furnace gas TRT turbine unit, including a rotor main shaft and a static blade installed in the casing. The characteristic is: both sides of the static blade constitute a gas inlet channel and a gas outlet channel respectively. , small axial flow fans are set at the shaft end air seals at both ends of the rotor main shaft. The axial flow fans are fixed on the rotor main shaft through shaft sleeves. The axial flow fans are concentric with the main shaft. When the rotor rotates, , driving the axial flow fan to rotate. The axial flow fan generates air flow opposite to that discharged from the shaft seal. The pressure generated by the reverse air flow is used to prevent the gas in the cylinder from leaking outward through the air gap at the shaft end. The casing outside the axial flow fan A balance pipe is communicated between the two side walls, and a gas balance valve is installed on the balance pipe. The upper part of the balance pipe is connected with the middle part of the casing. Gas is introduced through the balance pipe, and the introduced gas controls the balance pipe through the balance valve. Pressure, balance pipe pressure is controlled at atmospheric pressure or slightly positive pressure.