On-Load Boiler Cleaning with Steam

On-Load Boiler Cleaning with Steam CBW Clyde Bergemann Wesel 10.2007 - Rev. 5 March 16, 2018 FPK II Combustion Chemistry II Åbo Akademi University, Åbo

Content Steam sootblower solution Different types of steam sootblowers Functional aspects Deposit removal Selection of sootblowers Important design aspects

Sootblower 3

Sootblower in operation 4

Cleaning mechanism Retractable sootblower 5

Cleaning mechanism - Part Retractable sootblower 6

Content Steam sootblower solution Different types of steam sootblowers Functional aspects Deposit removal Selection of sootblowers Important design aspects

On-load Cleaning Systems Superheater/ Re-Heater Retractable Oscillating Axial Jet Blower Part Retractable SMART RSG / SMART Helix Water Furnace Wall Blower Water Cannon Economiser Part Retractable Rake Rotating Element Air heater/gas heater Rake Jet Blower Optimisation & Automation SMART CLEAN SMART CONTROL DeNOx Rake 8

On-load Cleaning Systems Cleaning systems for the furnace Blowing medium: water SMART Cannon Blowing medium: steam Wall blower VS-H

On-load Cleaning Systems Wall blower VS-H Functional principle The nozzle head with two opposite highperformance 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

On-load Cleaning Systems Wall blower Cleaning pattern Operating radius Geometrical blowing radius Nozzle inclination Rest Position Reverse Position Jet diversion Travel Spiral cleaning pattern due to wall blower type that advances into the boiler as it cleans

On-load Cleaning Systems Retractable Sootblower Functional principle The lance tube with two opposite highperformance 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

On-load Cleaning Systems Part Retractable Sootblower Functional principle 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

On-load Cleaning Systems Oscillating Sootblower Functional principle Retractable oscillating sootblower PS-P/RS-P 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

On-load Cleaning Systems Rake Sootblower - for the Economiser / Air Preheater / Gas-Gas Heater and DeNOx Functional principle 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

On-load Cleaning Systems Rotating Element Sootblower Functional principle 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 fluegas path

On-load Cleaning Systems SMART Jet Blower Functional principle 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

Content Steam sootblower solution Different types of steam sootblowers Functional aspects Deposit removal Selection of sootblowers Important design aspects

Sootblower 25

Retractable sootblower Travel: Blower valve: Feed tube: 0,3m - 20m over single or double rack (heavy-duty) Cast steel with adjustable throttle disc for varied blowing pressure 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 26

Retractable sootblowers (PS series) Lance Tube Guidance Electrical Equipment Covering System Rear Suspension Sealing & Scavenging Air Equipment Valve Actuating Mechanism Valve Wall Box Lance Tube Lance Tube Track Beam Blower Carriage Gear Motor Feed Tube Support Feed Tube Support 27

Content Steam sootblower solution Different types of steam sootblowers Functional aspects Deposit removal Selection of sootblowers Important design aspects

Failure due to axial crack formation Mussmann, UoToronto 2009 29

Failure due to surface pitting/axial crack formation Mussmann, UoToronto 2009 30

Failure due to spalling Mussmann, UoToronto 2009 31

Deposit break-up by steam jet Mussmann, UoToronto 2009 Thin deposit Distance = 9 cm Soft deposit Break-up duration: 3 ms 32

Deposit break-up by steam jet Mussmann, UoToronto 2009 Thick deposit Distance = 9 cm Soft deposit Break-up duration: 9.50 ms 33

Deposit asymmetry Actual deposits in boilers Boiler tubes Deposit Carry-over Flue gas Mussmann, UoToronto 2009 34

Deposit asymmetry Symmetric Asymmetric Deposit Steel tube Mussmann, UoToronto 2009 35

Deposit asymmetry 90 JET Mussmann, UoToronto 2009 36

Deposit asymmetry (0º vs. 90º) Mussmann, UoToronto 2009 37

Content Steam sootblower solution Different types of steam sootblowers Functional aspects Deposit removal Selection of sootblowers Important design aspects

Cleaning mechanism Retractable sootblower 39

Sootblower Design Toolbox System design Official Release 1.0 40

Sootblower Design Toolbox Project specific input parameters Calculation of fluid flow and mechanical stability including heat transfer Calculation of droop correction, steam consumption and jet profile 41

Sootblower Design Toolbox 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 42

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) 43

Content Steam sootblower solution Different types of steam sootblowers Functional aspects Deposit removal Selection of sootblowers Important design aspects

Quality of steam 45

Quality of steam 46

Recommended design principals for steam feeding systems 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 drain station. Short connecting pipe: Secure complete pre-heating; avoid cold pipe parts. 47