Controlling cooling flow in a sootblower based on lance tube temperature

Patent metadata

Field	Value
Publication number	US-9671183-B2
Application number	US-201313766131-A
Country	US
Kind code	B2
Filing date	Feb 13, 2013
Priority date	Dec 17, 2007
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

A cleaning system and method for cleaning heat transfer surfaces in a boiler using a temperature measuring system for measuring and monitoring wall temperature of an annular wall of the tube of a lance of one or more sootblowers. Controlling a flow of steam or other fluid through the tube during the cooling portions of the strokes based on wall temperature measurements from the temperature measuring system. Infrared or thermocouple temperature measuring systems may be used. The steam or other fluid may be flowed at a default flowrate that may be substantially zero until the temperature measuring system indicates the wall temperature of the annular wall begins to exceed a predetermined temperature limit which may be the softening point of the annular wall. Then the steam or other fluid is flowed at a rate greater than the default flowrate.

First claim

The invention claimed is:

1. A cleaning system for cleaning heat exchanger surfaces of one or more heat exchangers in a boiler, the cleaning system comprising:
one or more sootblowers,
each of the sootblowers having a lance with an elongated hollow tube and at least one nozzle at a distal end of the tube,
a temperature measuring system for measuring and monitoring a temperature of the one or more sootblowers during operation of the one or more sootblowers, wherein the temperature measuring system measures and monitors a wall temperature of an annular wall of the tube to generate wall temperature measurements, and
a control system for controlling steam flow through the tube and the at least one nozzle during operation of the one or more sootblowers based on the temperature measurements, wherein the control system is operable for controlling steam flow during cooling portions of insertion and extraction strokes to prevent the wall temperature measurements from exceeding a predetermined temperature limit.

2. A cleaning system as claimed in claim 1 wherein:
each of the sootblowers is operable for moving the lance in and out of the boiler in the insertion and extraction strokes,
the control system controls the flow of steam through the tube and nozzle during cleaning portions and the cooling portions of the strokes, and
the control system is operable for controlling the flow of steam during the cooling portions of the strokes based on the wall temperature measurements from the temperature measuring system.

3. A cleaning system as claimed in claim 1 wherein the predetermined temperature limit is a softening point or slightly less than the softening point of the tube.

4. A cleaning system as claimed in claim 2 wherein the temperature measuring system is an infrared temperature measuring system for measuring the wall temperature of the annular wall outside the boiler.

5. A cleaning system as claimed in claim 4 wherein the infrared temperature measuring system is operable for measuring the wall temperature of the annular wall outside and adjacent to the boiler.

6. A cleaning system as claimed in claim 5 wherein the predetermined temperature limit is a softening point or slightly less than the softening point of the tube.

7. A cleaning system as claimed in claim 2 wherein the temperature measuring system is a thermocouple temperature measuring system for measuring the wall temperature of the annular wall inside the boiler.

8. A cleaning system as claimed in claim 7 wherein the predetermined temperature limit is a softening point or slightly less than the softening point of the tube.

9. A cleaning system as claimed in claim 8 wherein the thermocouple temperature measuring system comprises thermocouples attached to the annular wall.

10. A cleaning system as claimed in claim 9 wherein the thermocouples are attached to an inside surface of the annular wall and are partially disposed from the inside surface of the annular wall in holes through and along a length of the annular wall.

11. A method of operating a cleaning system comprising:
using one or more sootblowers to clean heat transfer surfaces of one or more heat exchangers in a boiler,
flowing cleaning fluid through an elongated hollow tube of a lance of each of the sootblowers,
discharging the cleaning fluid from at least one nozzle at a distal end of the tube against the heat transfer surfaces,
measuring and monitoring a temperature of the one or more sootblowers during operation of the one or more sootblowers using a temperature measuring system that measures and monitors a wall temperature of an annular wall of the tube of each of the sootblowers to generate wall temperature measurements, and
controlling cleaning fluid flow through the one or more sootblowers during operation of the one or more sootblowers based on the temperature measurements of the one or more sootblowers, wherein the cleaning fluid flow through the tube and nozzle during cooling portions of insertion and extraction strokes is controlled to maintain the wall temperature measurements below a predetermined temperature limit.

12. A method as claimed in claim 11 further comprising:
moving the lance in and out of the boiler in the insertion and extraction strokes, wherein
the flow of the cleaning fluid through the tube and nozzle is controlled during cleaning portions and the cooling portions of the strokes, and
the flow of the cleaning fluid through the tube and nozzle during the cooling portions of the strokes is controlled based on the wall temperature measurements.

13. A method as claimed in claim 11 wherein the predetermined temperature limit is a softening point or slightly less than the softening point of the tube.

14. A method as claimed in claim 12 further comprising using an infrared temperature measuring system for the measuring and the monitoring of the wall temperature of the annular wall outside the boiler and wherein the cooling portions of the strokes occur only during the extraction strokes.

15. A method as claimed in claim 14 wherein the infrared temperature measuring system for measuring the wall temperature of the annular wall is used outside and adjacent to the boiler.

16. A method as claimed in claim 15 wherein the predetermined temperature limit is a softening point or slightly less than the softening point of the tube.

17. A method as claimed in claim 12 further comprising using a thermocouple temperature measuring system for the measuring and the monitoring of the wall temperature of the annular wall.

18. A method as claimed in claim 17 wherein the predetermined temperature limit is a softening point or slightly less than the softening point of the tube.

19. A method as claimed in claim 18 wherein the measuring of the wall temperature of the annular wall includes using thermocouples attached to the annular wall.

20. A method as claimed in claim 18 wherein the measuring of the wall temperature of the annular wall includes using thermocouples that are attached to an inside surface of the annular wall and are partially disposed from the inside surface of the annular wall in holes through and along a length of the annular wall.

21. A method as claimed in claim 11 wherein the cleaning fluid flows through the tube and nozzle during the cooling portions of the strokes at a flowrate equal to a default value unless the wall temperature of the annular wall exceeds or is about to exceed the predetermined temperature limit based on the wall temperature measurements.

22. A method as claimed in claim 21 wherein the default value is substantially zero.

23. A method as claimed in claim 22 wherein the predetermined temperature limit is a softening point or slightly less than the softening point of the tube.

24. A cleaning system as claimed in claim 2 , wherein the control system controls steam flow through the tube and nozzle by varying the flowrate of the steam through the tube and nozzle during operation of the one or more sootblowers based on the wall temperature measurements.

25. A method as claimed in claim 12 , wherein controlling cleaning fluid flow through the one or more sootblowers comprises varying the flowrate of the cleaning fluid through the one or more sootblowers during operation of the one or more sootblowers based on the wall temperature measurements of the one or more sootblowers.

26. A method as claimed in claim 12 , wherein the c

Assignees

• Int Paper Co

Inventors

• Jones Andrew K

Classifications

• F22B37/486 Primary

  Devices for removing water, minerals or sludge from boilers (F22B37/483, F22B37/50, F22B37/52 and F22B37/54 take precedence) · CPC title

• F22B37/56

  Boiler cleaning control devices, e.g. for ascertaining proper duration of boiler blow-down · CPC title

• F28G3/166

  from external surfaces of heat exchange conduits · CPC title

• F22B37/54

  De-sludging or blow-down devices {(F22B37/565 takes precedence)} · CPC title

• F28G15/003

  Control arrangements · CPC title