x4 (2018) - on-load boiler cleaning with steam -...

© C

BW

Cly

de B

erg

em

ann W

ese

l 10.2

007

-Rev. 5

On-Load Boiler Cleaning

with Steam

March 16, 2018FPK II – Combustion Chemistry II

Åbo Akademi University, Åbo

© CBW Clyde Bergemann Wesel - Alle Rechte vorbehalten

Content

� Steam sootblower solution

� Different types of steam sootblowers

� Functional aspects

� Deposit removal

� Selection of sootblowers

� Important design aspects

4 - On-Load Boiler Cleaning with Steam


3

Sootblower



4

Sootblower in operation




Cleaning mechanism –Retractable sootblower



Cleaning mechanism - Part Retractable sootblower


Content




� Deposit removal





8

On-load Cleaning Systems

Economiser� Part Retractable

Sootblowers� Rake Sootblowers� Rotating Element

Sootblowers

� RetractableSootblowers

� OscillatingSootblowers

� Axial Sootblowers� Jet Blower� Part Retractable

Sootblowers� SMART RSG /

SMART Helix Water

Superheater/Re-Heater

Furnace� Wall Blower� Water Cannon

Air heater/Gas heater� Rake Sootblowers� Jet Blower

� Rake Sootblowers

DeNOx

Optimisation & Automation

� SMART CLEAN� SMART CONTROL



“On-load“ Cleaning Systems

� Cleaning systems for the furnace

Blowing medium: water

SMART Cannon

Blowing medium: steam

Wall blower VS-H




Wall blower VS-H

Functional principle

� The nozzle head with two opposite high-performance nozzles is axially moved into the boiler

� The blowing process begins as soon as the nozzle head has reached the blowing position

� During this process the tube wall is cleaned in circular form

� A special valve control also enables cleaning of specific segments

� After performing the necessary number of rotations the nozzle head returns to its rest position




Wall blower – Cleaning pattern

Travel

Nozzle inclination

Geo

met

rical

blo

win

g ra

dius

Ope

ratin

g ra

dius

Jet

dive

rsio

n

Res

t P

ositi

on

Rev

erse

P

ositi

on

Spiral cleaning pattern due to wall blower type that advances into theboiler as it cleans



12




Sootblowers





SMART Helix Water





DeNOx






Retractable Sootblower


� The lance tube with two opposite high-performance nozzles, is helically moved into the boiler

� Consequently the blowing process begins shortly after the two nozzles have passed through the boiler wall

� During the blowing process the lance tube continues to move helically into the flue-gas path

� On reaching the end of travel position, the direction of movement changes and the lance tube returns to its rest position



14




Sootblowers





SMART Helix Water





DeNOx






Part Retractable Sootblower


� The blowing tube of the part retractable sootblower is equipped with high-performance nozzles over the whole length and is movably supported in the flue-gas path

� During the blowing process the blowing tube continues to move helically into the flue-gas path

� On reaching the end of travel position, the direction of movement changes and the blowing tube returns to its rest position

� The blowing tube remains partly in the flue-gas path




Oscillating Sootblower


� The lance tube with high-performance nozzles is moved in the boiler in oscillatory motion

� The blowing process begins as soon as the nozzles have passed through the boiler wall

� On reaching the end of travel position, the direction of movement changes and the lance tube returns to its rest position

Retractable oscillating sootblower PS-P/RS-P



17




Sootblowers





SMART Helix Water





DeNOx






Rake Sootblower - for the Economiser / Air Preheater / Gas-Gas Heater and DeNOx


� The blowing rake is equipped with high performance nozzles – blowing element remains in the flue-gas path

� During the blowing process the blowing rake continues to move axially into the flue-gas pass

� On reaching the end of travel position, the direction of movement changes and the blowing rake returns to its rest position



19




Sootblowers





SMART Helix Water





DeNOx






Rotating Element Sootblower


� The blowing tube is equipped with nozzles over the whole length and rotates within the flue-gas path

� During the blowing process the blowing tube performs a prescribed number of rotations

� The blowing process ends when the necessary number of rotations has been performed

� Blowing tube remains and is supported in flue-gas path



21




Sootblowers





SMART Helix Water





DeNOx






SMART Jet Blower


� Cleaning is carried out by axial movement of the lance tube in steps, while the heater basket rotates

� The SMART Jet is typically deployed below the heater with the media jets cleaning upwards, but can also be fitted above the heater as a pair

� The use of inverters and encoders allow the step-wise travel and positioning of the lance and nozzles to be infinitely controlled

� Choice of online cleaning modes air/steam, LP and HP water

� HP water jetting up to 300 bar(g) for online cleaning basket blockages



23




Sootblowers





SMART Helix Water





DeNOx





Content




� Deposit removal






Sootblower



Retractable sootblower

� Travel: 0,3m - 20m over single or double rack (heavy-duty)

� Blower valve: Cast steel with adjustable throttle disc for varied blowing pressure

� Feed tube:

� Stainless steel; Ø60 mm or Ø70 mm

� Lance tube:

� Creep resistant or high alloy steels

� O.D. Ø88,9 mm, Ø101,6 mm and Ø114,3 mm



Retractable sootblowers (PS series)

Valve Actuating Mechanism

Rear Suspension

Track BeamLance Tube Blower Carriage Feed Tube

Valve

Lance Tube Guidance Covering SystemElectrical Equipment

Gear MotorWall Box

Sealing & Scavenging Air Equipment

Feed Tube Support

Lance Tube Support


Content




� Deposit removal






Mussmann, UoToronto 2009

Failure due to axial crack formation




Failure due to surface pitting/axialcrack formation




Failure due to spalling


32

Break-up duration: 3 ms

Thin depositDistance = 9 cm

Soft deposit

Deposit break-up by steam jet




33

Thick depositDistance = 9 cm

Soft deposit

Break-up duration: 9.50 ms

Deposit break-up by steam jet




34

Deposit asymmetry – Actualdeposits in boilers

Flue gas

Deposit

Carry-over

Boiler tubes




35

Asymmetric

Deposit asymmetry

Deposit

Steel tube

Symmetric




36

0°

JET

90°



Deposit asymmetry


37

Deposit asymmetry (0º vs. 90º)




Content




� Deposit removal






Cleaning mechanism –Retractable sootblower


40

Sootblower Design Toolbox

Official Release 1.0

System design



41


� Project specific input parameters

� Calculation of fluid flow and mechanical stability including heat transfer

� Calculation of droop correction, steam consumption and jet profile



42



Important design parameter for Steam sootblowers:

� Fuel and fuel specification

� Steam pressure & temperature (design and operation)

� Location of sootblower in boiler

� Distances and configuartion of heating elements, dimensions of elements (for cleaning)

� Fluegas temperature (max)

� Control setup and electrical configurations


43

Selection of blowing elements

BFB (Bubbling Fluidized Boiler) boilers

Example:

� BFB boiler burning wood waste

� Steam 25 bar(g) and 400 °C

� Superheater:

� Max. fluegas temperature 900 °C

� Retractable sootblower

� Blowing element material 13CrMo44(creep: max temp. 560 °C)

� Boiler bank:

� Max. fluegas temperature 720 °C

� Part Retractable sootblower

� Blowing element material X10CrAl13(creep: max temp. 800 °C)



Content




� Deposit removal






Quality of steam



�

� Piping arrangement:

� Inclination for proper draining.

� Avoid “Christmas Tree” piping layout.

� Pre-heating control:

� Draining temperature controlled, not time controlled.

� Cleaning sequence:

� Start with sootblower nearest to the drainstation.

� Short connecting pipe:

� Secure complete pre-heating; avoid“cold” pipe parts.

Recommended design principals for steamfeeding systems


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