Manufacturing technology of flue for gas turbine exhaust system

Abstract

The invention discloses a manufacturing technology of a flue for a gas turbine exhaust system. Chrome molybdenum low-alloy steel is selected to be used as a blank material, and the chrome molybdenum low-alloy steel comprises, by mass, 0.3 percent to 0.32 percent of carbon, 0.18 percent to 0.36 percent of silicon, 0.50 percent to 0.70 percent of manganese, 0.90 percent to 1.10 percent of chrome, 0.20 percent to 0.30 percent of molybdenum, 0 percent to 0.02 percent of phosphorus, 0 percent to 0.025 percent of sulphur, 0 ppm to 1.8 ppm of hydrogen, 0 percent to 0.40 percent of nickel, 0 percent to 0.03 percent of vanadium, 0 percent to 0.30 percent of copper, 0 percent to 0.9 percent of residual elements and the balance Fe. Boron-modified organic silicon resin high-temperature-resisting coatings are selected to coat the inner surface and the outer surface of the flue. By means of the manufacturing technology of the flue for the gas turbine exhaust system, the high wear-resisting, pressure-resisting, high-temperature-resisting and corrosion-resisting capability of a metal expansion joint can be greatly improved; operation is easy and convenient; and the production efficiency of the flue can be improved.

Description

technical field [0001] The invention relates to the field of manufacturing gas turbine intake and exhaust systems, in particular to a manufacturing process for the flue of the gas turbine exhaust system. Background technique [0002] The outlet of the gas turbine and the heating surface of the waste heat boiler often need to be connected by a transitional flue; the size difference between the outlet of the gas turbine and the inlet of the heating surface of the waste heat boiler is very large, and the former is in a disadvantageous position relative to the lower end of the latter; the traditional flue uses The lower surface has a plane with a certain inclination angle to complete the expansion of the space from the inlet to the outlet, thereby reducing the impact and wear of the pressure on the flue. [0003] The above structure leads to poor flue gas flow in the flue. The flue gas generally enters the inlet plane of the transition flue at a flow rate of 60-150m / s, or even 2...

AI Technical Summary

Problems solved by technology

[0003] The above structure leads to poor flue gas flow in the flue. The flue gas generally enters the inlet plane of the transition flue at a flow rate of 60-150m / s, or even 200m / s, and then forms a high-speed main airflow at the bottom of the transition flue. However, the flow velocity in the middle and upper parts of the flue is very low, generally less than 5m / s, and due to the large velocity gradient, a strong entrainment airflow is generated at the inlet plane of the waste heat boiler, and a large flow is formed near the middle and upper parts. Vortex, thus forming a large-scale recirculation zone, resulting in extremely uneven distribution of flue gas flow in each heating surface of the waste heat boiler; thus increasing the pressure on the flue locally, greatly shortening its service life, and seriously affecting the heat transfer of the waste heat boiler tube bundle performance, which is more likely to cause greater potential safety accidents