Gas bearing turbine expansion machine

Abstract

The invention provides a gas bearing turbine expansion machine, and relates to the field of mechanical equipment. The gas bearing turbine expansion machine comprises a shell and a center shaft arranged in the shell. A left gas bearing and a right gas bearing are arranged on the left side and the right side of the center shaft in the length direction. The left gas bearing is connected with an expansion machine body through a sealing heat insulation sleeve, and the right gas bearing is connected with a draught fan wheel through a sealing heat insulation plate. The outer side of an expansion wheel is provided with a turbine volute fixed to the left side of the shell. The outer side of the draught fan wheel is provided with a draught fan volute fixed to the right side of the shell. The right side of the draught fan volute is fixedly connected with a draught fan wheel guiding sealing cover. Two radial through holes are formed in the sealing heat insulation plate and serve as a normal-temperature sealing gas inlet and an instrument high-temperature waste gas exhaust port correspondingly. A water path channel is arranged in the draught fan wheel guiding sealing cover and used for leading-in of circulation cooling water. Through the design, the draught fan wheel rear temperature can be effectively reduced, the design adapts to higher-rotation-speed expansion machines, the expansion efficiency is improved, the running adaptive range of the expansion machine is enlarged, and higher market competiveness is achieved.

Description

technical field [0001] The invention relates to the field of mechanical equipment, in particular to a gas bearing turbo expander. Background technique [0002] Turboexpander is a low-temperature refrigeration machine and a key supporting unit for air separation products. It is widely used in iron and steel, smelting, petrochemical, glass and other industries. The gas bearing turboexpander is the most promising product among the turboexpanders. It has the advantages of small size, light weight, low price, high efficiency, convenient operation and maintenance, etc., and also meets the national requirements for energy saving and emission reduction. [0003] For example, the gas bearing turbo expander disclosed in Chinese invention patent No. ZL200810157098.6 includes an intermediate casing, a turbine volute is installed on the left end of the intermediate casing, and a turbocharger volute is installed on the right end of the intermediate casing; the intermediate casing A rotor...

AI Technical Summary

Problems solved by technology

[0005] The amount of expansion is an important parameter to measure the efficiency of the expander. The larger the amount of expansion, the greater the total cooling capacity of the expander; in actual production, the method of increasing the inlet air volume of the expansion end of the expander and increasing the speed of the expansion wheel and the fan wheel is generally adopted. Increase the expansion amount, but the expansion wheel and the fan wheel rotate too high, which will cause the fan brake wheel to further work and consume mechanical energy, and the heat that cannot be dissipated at the fan end will cause the temperature at the fan end to rise rapidly, resulting in the speed of the fan wheel. Further improvement cannot achieve the technical effect of increasing the amount of expansion; for example, when the fan wheel speed reaches 90,000 rpm or above, on the one hand, a large pressure difference will be generated between the fan end of the expander and the internal bearing side, which is prone to accidents ; On the other hand, due to the high speed of the fan wheel, it will increase the work and generate more heat when the fan end brakes, which will cause the outlet temperature of the fan wheel to be 100°C or more higher than the inlet temperature. At this time, the fan wheel will always remain low The rotation speed of the expansion wheel cannot increase the rotation speed, and the expansion volume of the expander cannot be increased.

[0006] The existing technical solutions can only be applied to gas bearing expanders whose temperature rise at the brake end generally does not exceed 50°C. If high-temperature gas flows to the bearing, the inner hole of the bearing will expand, and the fit clearance will also change. The bearing capacity is greatly reduced, especially when the total radial clearance reaches more than 0.10mm, the stability of the bearing will be greatly deteriorated, the rigidity of the bearing will decrease, and at the same time, the central shaft will have a strong surge, which is easy to make the central shaft and The bearings will burn out due to contact, so that the complete set of equipment will be shut down, resulting in great economic losses

In addition, the flow of high-temperature gas into the bearing will also cause axial expansion of the bearing, which will reduce the total axial clearance, cause the flow of bearing gas to enter to become smaller, and the axial bearing capacity will also decrease

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