SU1714295A1 - Air preheater - Google Patents

Abstract

The invention relates to the regeneration of flue gases by heating air and can be used in fuel combustion plants. The goal is to increase reliability by protecting the plate heater of the air heater (VP) against low temperature corrosion. The cold air successively passes through the glass-tube VP 11 and 12, as well as the metal-tube VP 14, and is supplied to the burner 15 of the first 16; A part of the air is withdrawn and injects into the gaps of VP 11 and 12. In this case, the structural elements, the limiting gaps 7, are heated to a temperature higher than the dew point, thus eliminating the corrosion of the said elements. 2 or .. • fcf '' * ^ fe

Description

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The invention relates to an air preheater for heat recovery of flue gases capable of causing sulfuric acid corrosion when cooled below the dew point, and can be used in heat and power engineering, metallurgy, chemical and other industries where heat is recovered from flue gases capable of causing low temperature sulfuric acid corrosion.

Air heaters are known that contain a bundle of non-metallic, mainly glass pipes. In these air preheaters, the possibility of an increase in air temperature is limited by the area of condensation of water vapor and the corrosive effect of condensate from flue gases resulting from this. Steel carrier plates and bounding walls in glass tube air heaters experience these adverse effects despite the use of high quality materials and thickness margin. To prevent the temperature from dropping below the dew point of the wall where condensation from the flue gases occurs, heat up to a temperature above the dew point.

In such air preheaters, the glass tubes in the tube plates are sealed with a sealing element with a stop ring welded on or screwed to it. As a result, a gland-type seal is formed between the glass tube and the surrounding tube plate or flange of the tube. ,

A disadvantage of the known air preheater is that this design is not suitable for heating tubular elements that are susceptible to corrosion. In addition, with this type of fastening and sealing of glass pipes, there is no heat transfer between the glass pipe and the tube plate.

Closest to the present invention, there is an air preheater comprising a bundle of nonmetallic, mainly glass pipes, installed at their ends in the openings of tube plates, each made in the form of a pair of plates; fastened together by a strapping device and placed one relative to another with the formation of a gap, each pipe in the zone of the latter being provided from the side of one of the plates with a sealing end. The low temperature of this air preheater is the low protection of the plates of the pipe plates facing the flue gases from low-temperature sulfuric acid corrosion during deep utilization of the gases, as the temperature of the plates of the same utilization decreases below the dew point at which corrosion develops. The disadvantage is eliminated by the fact that each pipe in the gap between the plates of the tube plate is additionally covered by a metal sleeve adjoining one end to the corresponding sealing ring to form a tight contact, opposite the front end 1THE is fixed to the corresponding plate, and the gap between the plates is connected to the heated air line. .

FIG. 1. An air preheater system is shown, including an air preheater; in fig. 2 - pipe air preheater.

The air heater contains a bundle of non-metallic, predominantly glass Tubes 2, mounted with their ends in the holes of tube plates. each made in the form of a pair of plates 1 and 3, fastened together by a strapping device - bolts 8 and placed one relative to another with the formation of Zazo 7, and each pipe 2 in the zone of the gap 7 is provided on the side of plate 1 with a sealing ring 6 and covered by a metal sleeve 5 adjacent one ring to the ring 6 with the formation of tight contact, and the opposite end tightly (for example, welding) bonded to the plate 3. The gap 7 between the plates 2 and 3 is connected to the line 13 of heated air. Plate 3 separates bundle 4 of pipe 2 from gap 7.

The air preheating system for the burner 15 of the furnace 16 includes two glass tube air preheaters 11 and 12 and a metal pipe air preheater 14, as well as a fan 9 of the blowing air. Air heaters 11, 12, and 14 are connected by gases with line 19 and through the air with line 13. Line 13 is equipped with a fan 17. to extract a portion of heated air and a gate 18 for controlling the flow rate of this part. The fan 9 is provided with a suction nozzle 10. Behind the air heater 11 there is a discharge duct 20 with a drainage 21.

The air heating system works as follows.

The cold air intake air blower fan 9 is directed to the first glass tube air heater t1, where it passes through glass pipes 2. Then the blow air passes the second glass tube air heater 12 in the same way and enters, with an elevated temperature, the metal tube air heater 14, The heated blast air is then supplied to the burner. 15

Claims (1)

Formula of the invention An air heater containing 5 a bundle of non-metallic, mainly glass pipes, installed at their ends in the openings of the pipe boards, each made in the form of a pair of plates fastened together by a clamping device 10 and placed one relative to the other with the formation of a gap, each pipe in the zone of the latter provided on the side of one of the mentioned plates with a sealing ring, characterized in that, with 15 the purpose of increasing reliability by protecting the plates of the tube plate from low temperature corrosion, and deep utilization - heat of heating gases, each pipe in the gap zone is additionally covered by a metal sleeve adjacent one end to the corresponding o-ring to form a tight contact, and the other end is tightly bonded to the corresponding plate, and the gap 25 between the plates is connected to the heated line air. 8 5 '.