An Arrangement in a Thermal Process, and a Method for Measuring the Thickness of a Contamination Layer

Patent metadata

Field	Value
Publication number	US-2016245599-A2
Application number	US-201314649542-A
Country	US
Kind code	A2
Filing date	Nov 25, 2013
Priority date	Dec 5, 2012
Publication date	Aug 25, 2016
Grant date	—

Abstract

An arrangement of a thermal device and a surface reflecting and/or scattering electromagnetic radiation in the inner part of the thermal device. A source of electromagnetic radiation is arranged at a first distance (L1) from the surface, and a detector of electromagnetic radiation is arranged at a second distance (L2) from the surface. The source is configured to emit radiation to the surface, which is reflected and/or scattered from the surface as reflected radiation. The detector receives reflected radiation; and the processing unit determines data dependent on the first and/or second distance by the emitted and reflected radiation. A wall of the thermal device has a window or aperture for emitting an optical signal from the light source to the surface. An electromagnetic distance measurement device measures the thickness or the increase in the thickness of a contamination layer from a thermal device.

First claim

1 - 18 . (canceled)

19 . An arrangement comprising:
a thermal device being a boiler, a gasification reactor, a pyrolysis reactor, or a torrefaction reactor, the thermal device comprising walls which enclose inner parts of the thermal device; a surface reflecting and/or scattering electromagnetic radiation in the inner part of the thermal device; a detector of electromagnetic radiation arranged at a second distance from said surface; and a processing unit;
wherein the arrangement further comprises:
a laser source arranged at a first distance from said surface and outside the thermal device;
a window or an aperture configured to transmit an electromagnetic signal from the laser source to said surface comprised by a wall of the thermal device, in which arrangement
the laser source is configured to emit radiation from the laser source to said surface, said radiation being reflected and/or scattered in the form of reflected radiation from said surface;
wherein the detector of electromagnetic radiation is configured to receive the reflected radiation, and
the processing unit is configured to determine the thickness or the increase in the thickness of a contamination layer by
determining, during a first period of time, by means of emitted radiation and reflected radiation, data dependent on the first and/or the second distance, and by means of said data, a first length;
determining, during a second period of time, by means of emitted radiation and reflected radiation, data dependent on the first and/or the second distance, and by means of said data, a second length; and
determining, by means of the first length and the second length, the increase in the thickness of the contamination layer or the thickness of the contamination layer, by using the first length as an initial reference length.

20 . The arrangement according to claim 19 , wherein
the laser source is configured to emit light at least at a wavelength between 300 nm and 800 nm; and the detector of electromagnetic radiation is configured to receive reflected light having said wavelength.

21 . The arrangement according to claim 19 , wherein the processing unit is configured
to determine the thickness of the contamination layer in such a way that said surface is the surface of said contamination layer.

22 . The arrangement according to claim 19 , further comprising:
a pipe which is configured such that the electromagnetic signal is configured to pass through the pipe from said laser source to said surface; and means for supplying protective gas to said pipe.

23 . The arrangement according to claim 19 , wherein the laser source is configured to be
movable, turnable, or both movable and turnable
in relation to the surface.

24 . A thermal system comprising:
an arrangement according to claim 19 ; and a cleaning device for cleaning a surface of the thermal device, in which system said processing unit is configured to control said cleaning device by means of said data.

25 . A thermal system comprising:
an arrangement according to claim 19 ; and a cleaning device for cleaning the surface of the thermal device; a control device for controlling said cleaning device, in which system said processing unit is configured to transmit said data depending on the first and/or second distance to said control device, wherein said control device is configured to receive said data, and said control device is configured to control said cleaning device by means of said data.

26 . A method for measuring the thickness of a contamination layer or an increase in the thickness of a contamination layer on a thermal device, wherein
the thermal device is a boiler, a gasification reactor, a pyrolysis reactor, or a torrefaction reactor, the thermal device comprises walls enclosing inner parts of the thermal device, and a surface is arranged in the inner part of the thermal device,
wherein
at least one of the walls of the thermal device further comprises a window or an aperture configured to transmit an electromagnetic signal from said laser source to said surface, and the method comprises:
emitting electromagnetic radiation from a laser source to the surface, said radiation being reflected and/or scattered in the form of reflected radiation from said surface, the laser source being arranged at a first distance from said surface and outside the thermal device;
receiving said reflected radiation by a detector of electromagnetic radiation, the detector of electromagnetic radiation being arranged at a second distance from said surface;
determining, during a first period of time, by means of emitted radiation and reflected radiation, data dependent on the first and/or the second distance, and by means of said data, a first length;
determining, during a second period of time, by means of emitted radiation and reflected radiation, data dependent on the first and/or the second distance, and by means of said data, a second length; and
determining, by means of the first length and the second length, the increase in the thickness of the contamination layer or the thickness of the contamination layer by using the first length as an initial reference length.

27 . The method of claim 26 comprising using an electromagnetic distance measurement instrument during the operation of the thermal device.

28 . The method according to the claim 26 , further comprising:
emitting electromagnetic radiation at least at a wavelength between 300 nm and 800 nm, and receiving radiation having said wavelength.

29 . The method according to the claim 26 , wherein said surface is a surface of a contamination layer, the contamination layer being arranged
on the surface of a wall in the inner part of the thermal device, such as a furnace or a flue gas duct, or on a surface of a heat exchanger, such as a superheater, an evaporator, an economizer, or an air preheater.

30 . The method according to the claim 26 , further comprising:
determining data depending on the first and/or the second distance according to the method of claim 26 during several periods of time and determining several length components by means of said data depending on the first and/or the second distance, each length component relating to said period of time; and determining a first thickness of the contamination layer or a reference length statistically by applying said several length components.

31 . The method according to claim 30 , further comprising:
determining other data depending on the first and/or the second distance during several other periods of time, and determining several other length components by means of said other data depending on the first and/or the second distance, each other length component relating to said other period of time; and determining the thickness or an increase in the thickness of the contamination layer statistically by applying said several length components and said several other length components.

32 . The method according to claim 30 , wherein
said several periods of time cover a time span, the length of the span being at least 30 seconds.

33 . The method according to claim 31 , wherein
said several other periods of time cover a time span, the length of the span being at least 30 seconds.

34 . A method for cleaning and/or maintaining a thermal device,
the method comprising determining data depending on the first and/or the second distance by a method according to claim 26 , by means of emitted radiation and reflected radiation, and further determining the thicknes

Assignees

• Valmet Technologies Oy

Inventors

• Maunula Joni

Classifications

• G01B11/0625

  with measurement of absorption or reflection · CPC title

• F28G15/003 Primary

  Control arrangements · CPC title

• F23J3/023 Primary

  cleaning the fireside of watertubes in boilers · CPC title

• G01S17/08 Primary

  for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48) · CPC title

• F23M11/042

  Viewing ports of windows · CPC title