Heat-transfer pipe of flue gas cooler

Abstract

The invention relates to a heat-transfer pipe of a flue gas cooler, which comprises base pipes and fin groups, wherein the cross section of the base pipe is in an oval shape, and each fin group comprises two rectangular steel sheets; one side of the middle of each steel sheet, which is inlaid on the oval base pipe, is provided with an oval arc gap the shape of which is similar to that of the base pipe, and the two rectangular steel sheets of each fin group are symmetrically inlaid and welded on the oval base pipe; and another fin group is laid every 10 to 30 mm pitch along the length direction of the base pipe in the same way until the fin group covers the whole pipe, accordingly, the heat-transfer pipe of the flue gas cooler is formed. Since the heat-transfer pipe of the flue gas cooler has the advantages of low flue gas side flow resistance, low energy consumption, ash deposition and wear resistance and the like when being applied to the flue gas cooler, the heat-transfer pipe is more suitable for low-temperature and dusty occasions such as desulfurization process flue gas coolers of flue gas in fuel electric plants and the like.

Description

technical field [0001] The invention relates to a heat transfer tube of a flue gas cooler. Background technique [0002] In the past ten years, the desulfurization process of large-scale power plants above 300MW in my country has basically adopted the relatively mature limestone-gypsum wet desulfurization process. In this process, a flue gas-flue gas heat exchanger (GGH) is usually installed. In the GGH, a On the one hand, the untreated flue gas entering the absorption tower is reduced from 120 to 130°C to about 80°C; The flue gas outlet baffle enters the chimney and is discharged into the atmosphere. The operation practice in recent years shows that GGH has little effect in the desulfurization system (FGD), but it brings many disadvantages. First of all, the investment cost is high (accounting for about 15% of the total investment of FGD); secondly, the energy consumption of water, electricity and compressed air during operation is large, and the operation cost is high; mor...

AI Technical Summary

Problems solved by technology

Although this process eliminates the need for GGH, it brings four problems: ① The waste heat of the untreated flue gas from 120 to 130 ℃ to about 80 ℃ is not used and lost in vain; The amount of evaporated water in the tower increases by more than 20%, which leads to an increase in the water consumption of the desulfurization device; ③The steam formed by the water sprayed in the absorption tower is discharged from the chimney together with the flue gas, increasing the amount of water discharged from the chimney. The volume of the flue gas-steam mixture and the corresponding flow resistance increase the power consumption (power consumption) of the fan; ④Due to the high moisture content of the flue gas, it is easy to form condensed water droplets and white plumes (commonly known as white smoke ), will cause weak acid rain and splashing of lime slurry to the surrounding environment of the power station

Generally, the wind pressure margin of the booster fan is not large, so whether it is from the perspective of energy saving or booster fan transformation, the resistance on the smoke side of the flue gas cooler is required to be as small as possible, otherwise the efficiency of waste heat recovery and increase will be reduced. Difficulty and investment cost of renovation project

[0008] (2) The heat transfer coefficient on the flue gas side (relative to the total external area of ​​the fin tube) is relatively small

[0010] (3) Easy to accumulate dust

[0012] (4) The ability to resist fly ash wear is not strong enough, and the service life is not long enough

[0013] The operation practice shows that the wear of the wound spiral fin at the root is relatively serious, especially when the fin is wide, the winding speed is too fast during the manufacturing process, wrinkles appear on the inner ring of the fin due to compression, and the smoke flow rate is selected Higher, more prone to wear near the rib root

Images