Thermal device, its use, and method for heating a heat transfer medium

Patent metadata

Field	Value
Publication number	US-2016258692-A1
Application number	US-201415028700-A
Country	US
Kind code	A1
Filing date	Sep 29, 2014
Priority date	Oct 11, 2013
Publication date	Sep 8, 2016
Grant date	—

Abstract

A heat exchanger pipe in a flow duct for gases. The pipe first section has a second section with an inner pipe for transferring heat transfer medium; an outer pipe that radially encloses a part of the inner pipe; and a medium layer between the outer pipe and the part of the inner pipe. The second section of the heat exchanger pipe bends less than 90 degrees. Furthermore, the first section is insulated in its entirety, or non-insulated in the vicinity of other heat recovery surfaces only. In the device the temperature of the heat transfer medium flowing in the inner pipe is at least 500° C., the temperature of the outer surface of the outer pipe is higher than 600° C., or an auxiliary agent is fed to the thermal device.

First claim

1 - 23 . (canceled)

24 . A thermal device comprising
at least a first wall delimiting a flow duct for gases; and a heat exchanger pipe comprising at least an inner pipe, at least a first first section of said heat exchanger pipe being placed in said flow duct for gases and extending in said flow duct for gases from said first wall to said first wall or to a second wall delimiting the flow duct for gases; the heat exchanger pipe comprising a second first section extending in said flow duct for gases from one wall to the same or another wall; and several other heat transfer pipes inside the walls of the flow duct for gases, for recovering heat, in which thermal device; said first first section of the heat exchanger pipe comprises: a second section of the heat exchanger pipe, extending in said flow duct for gases, wherein said second section of the heat exchanger pipe comprises: at least a section of the inner pipe, for transferring heat transfer medium from the first end to the second end of the inner pipe and for recovering heat by the heat transfer medium, an outer pipe which radially encloses said section of the inner pipe, and a medium layer placed between said outer pipe and said section of the inner pipe in the radial direction; and said heat exchanger pipe and said other heat transfer pipes constitute a continuous flow duct for the heat transfer medium, for heating the heat transfer medium, in which thermal device (A,i) the inner pipe of the first first section of said heat exchanger pipe is non-insulated from the flow duct for gases in one or more non-insulated areas in such a way that the distance from all points of the non-insulated areas of the first first section to the other heat recovery surfaces of the thermal devices is not greater than 15 cm; or (A,ii) said first first section of the heat exchanger pipe, or the inner pipe of said first first section of the heat exchanger pipe, is insulated, over its entire length, from the flow duct for gases by means of said outer pipe and/or an insulator, and (B,i) the second first section or its inner pipe is non-insulated from the flow duct for gases in one or more non-insulated areas in such a way that the distance from all the points in the non-insulated areas of the second first section to the other heat recovery surfaces of the device is not greater than 15 cm; or (B,ii) the second first section or the inner pipe of said second first section is, over its entire length, insulated from the flow duct for gases by means of a second outer pipe and/or an insulator, wherein (C,i) said flow duct for the heat transfer medium comprises the first first section of said heat exchanger pipe as the heat transfer element placed last in the flow duct of gases, in the direction of the flow of the heat transfer medium, or (C,ii) said flow duct for the heat transfer medium comprises the first first section of the heat exchanger pipe placed last in the flow duct for gases, in the flow direction of the heat transfer medium, and at least one heat transfer pipe placed downstream in the flow duct for gases, in the direction of flow of the heat transfer medium, and said first first section of the last heat exchanger pipe is arranged, in the flow direction of the gas flowing outside the outer pipe, upstream of said heat transfer pipes placed downstream in the flow duct for gases in the flow direction of the heat transfer medium, and (D) said inner pipe connects said first first section of the heat exchanger pipe to said second first section of the heat exchanger pipe outside said flow duct for gases, said second first section of the heat exchanger pipe is placed downstream of said first first section of the heat exchanger pipe in the flow direction of the medium flowing in the inner pipe, and said second first section of the heat exchanger pipe is placed downstream of said first first section of the heat exchanger pipe in the flow direction of the gas flowing outside the heat exchanger pipe.

25 . The thermal device according to claim 24 , wherein
said second section of the heat exchanger pipe extends in a straight line or bends less than 90 degrees; or said second section of the heat exchanger pipe bends at least 90 degrees.

26 . The thermal device according to claim 24 , wherein
said second section of the heat exchanger pipe extends from said first wall of the device to said flow duct for gases; advantageously, said second section of the heat exchanger pipe comprises said first first section of the heat exchanger pipe.

27 . The thermal device according to claim 24 , wherein
said first first section of the heat exchanger pipe comprises a thermally insulated section in said flow duct for gases, in which thermally insulated section the inner pipe is not enclosed by an outer pipe, and in which thermally insulated section the inner pipe is thermally insulated from the gases in the flow duct by means of a thermal insulator, or the inner pipe is enclosed by an outer pipe, and in said thermally insulated section the outer pipe is thermally insulated from the gases in the flow duct by means of a thermal insulator.

28 . The thermal device according to claim 27 , wherein
(A)
said second section of the heat exchanger pipe extends from said first wall of the device to said thermally insulated part, or
(B)
the thermal device comprises an insulator adjacent to the wall, extending from said first wall of the device to the flow duct for gases,
said second section of the heat exchanger pipe extends from said insulator adjacent to the wall to said thermally insulated section, and
said insulator adjacent to the wall is configured to insulate at least the inner pipe of the heat exchanger pipe from the flow duct for gases.

29 . The thermal device according to claim 24 , wherein
said first first section of the heat exchanger pipe is horizontal, or the longitudinal part of said first first section of the heat exchanger pipe forms, at each point, and angle smaller than 30 degrees to the horizontal plane.

30 . The thermal device according to claim 24 , comprising
means for feeding an auxiliary agent, for feeding an auxiliary agent to the process, the part of the means for feeding an auxiliary agent being placed in the flow duct for gases, and part of the means for feeding an auxiliary agent being arranged down-stream of said or a first first section of said heat exchanger pipe in the flow direction of gases.

31 . The thermal device according to claim 30 , comprising
a first heat exchanger comprising said heat exchanger pipe and further several heat exchanger pipes which comprise an inner pipe, at least one outer pipe and a medium layer placed between the outer pipe and the inner pipe parts, a second heat exchanger comprising several heat transfer pipes, the first heat exchanger being arranged upstream of said second heat exchanger in the flow direction of gases, the second heat exchanger being spaced from the first heat exchanger, wherein a space is left between the second heat exchanger and the first heat exchanger, and said part of the means for feeding an auxiliary agent being arranged in said space.

32 . The thermal device according to claim 24 , wherein
the wall of the thermal device comprises a housing, the housing protrudes outwards from the wall of the thermal device, seen from the flow duct for gases, the housing comprises a through hole for conveying said inner pipe out of the process area of the thermal device or from the flow duct for gases, and (i) the outer surface of the housing is provided with said outer pipe, (ii) an insulator adjacent to the wall extends from the inner surface of the housing to the flow duct for gases; or (ii

Assignees

• Valmet Technologies Oy

Inventors

• Kainu Vesa

Classifications

• F28F1/12 Primary

  the means being only outside the tubular element · CPC title

• F28F19/00

  Preventing the formation of deposits or corrosion, e.g. by using filters {or scrapers} · CPC title

• F22B37/12

  Forms of water tubes, e.g. of varying cross-section · CPC title

• F22B37/107 Primary

  Protection of water tubes · CPC title

• F22B37/06

  Flue or fire tubes; Accessories therefor, e.g. fire-tube inserts · CPC title