CBW Clyde Bergemann Wesel 10.2007 - Rev. 5 Applications - Examples on choosing the cleaning strategy March 16, 2018 FPK II Combustion Chemistry II Åbo Akademi University, Åbo
Choosing a Cleaning Strategy Conventional Selection and Design of Cleaning Systems Clyde Bergemann experience Installation of cleaning systems in more than 3000 plants Installation of more than 2000 heat flux sensors Conventional analysis of deposition characteristics Visual observations by plant personnel Deposit analysis during outages Boiler inspection camera 2
Choosing a Cleaning Strategy Advanced Selection and Design of Cleaning Systems Simulation of the boiler at the actual operational condition Combustion simulation Heat flux distribution Ash deposition map Ash deposition analysis in furnace Designing a cleaning strategy Choice and positioning of diagnostic tools Choice and positioning of cleaning systems Realisation of the cleaning strategy 3
Example 1 Operational Problems Boiler with russian T-design Fuel: Bitumious coal Thermal power: 150 MW No cleaning systems installed in furnace Actual Situation Major problems with ash deposition within the entire furnace Severe and continous slagging in ash hopper region Consequences Unscheduled outages up to 20 times per year Manual removal of slag deposits in the ash hopper region High risk for accidents and inefficient operation 4
Basic Boiler Simulation: Boiler with T-design 5
Basic Boiler Simulation: 3D-Boilermodel Burner: 1.4 Mio. Zellen (Resolution: 0,5 6 cm) Furnace: 2.9 Mio. Zellen (Resolution : 4 25 cm) Convective Zone: 0.3 Mio. Zellen (Resolution : 20 35 cm) 6
Basic Boiler Simulation: Velocity Distribution Velocity [m/s] RW RW FW FW 7
Basic Boiler Simulation: Temperature Distribution Temperature [ C] RW FW 8
Basic Boiler Simulation: Wall Heat Flux Distribution 32 28 Heat Flux [kw/m 2 ] Furnace Height [m] 24 20 16 12 8 4 0 4 8 12 16 20 24 28 32 36 Front Wall L.H. Side Wall Rear Wall R.H. Side Wall 9
Basic Boiler Simulation: Results Simulation Measurement FEGT [ C] 1200 1202 Fluegas after ECO [ C] 380 376 CO [mg/nm 3 ] 13 ~ 10 NOx [mg/nm 3 ] 920 855 910 UBC [Mass-%] 1.25 2.4 10
Design Online-Cleaning System: Ash Deposit Map Ash deposition simulation with critial viscosity: 10 5 Pa s Furnace Height [m] 32 28 24 20 16 Fraction of ash deposited: 10.2 % Deposition rate [g/m 2 s] 12 8 4 0 4 8 12 16 20 24 28 32 36 Front Wall L.H. Side Wall Rear Wall R.H. Side Wall 11
Design Online-Cleaning System: Diagnostics and Cleaning Device 1. SMART Furnace System incl. SMART Flux Sensors 2. Water Cannons for cleaning furnace and hopper region 12
Design Online-Cleaning System: : Cleaning Need in Furnace Ash deposition simulation with critial viscosity: 10 5 Pa s Furnace Height [m] 32 28 24 20 16 Fraction of ash deposited: 10.2 % Deposition rate [g/m 2 s] 12 8 4 0 4 8 12 16 20 24 28 32 36 Front Wall L.H. Side Wall Rear Wall R.H. Side Wall Total need for cleaning 13
Design Online-Cleaning System: Realised Cleaning in Furnace Ash deposition simulation with critial viscosity: 10 5 Pa s Furnace Height [m] 32 28 24 20 16 Fraction of ash deposited: 10.2 % Deposition rate [g/m 2 s] 12 8 4 0 4 8 12 16 20 24 28 32 36 Front Wall L.H. Side Wall Rear Wall R.H. Side Wall Realised cleaning region 14
Design Online-Cleaning System: Positioning of Sensors Ash deposition simulation with critial viscosity: 10 5 Pa s Furnace Height [m] 32 28 24 20 16 Fraction of ash deposited: 10.2 % Deposition rate [g/m 2 s] 12 8 4 0 4 8 12 16 20 24 28 32 36 Front Wall L.H. Side Wall Rear Wall R.H. Side Wall SMART Flux Sensor 15
Design Online-Cleaning System: Positioning of Sensors 32 28 Heat flux [kw/m 2 ] Furnace Height [m] 24 20 16 12 8 4 0 4 8 12 16 20 24 28 32 36 Front Wall L.H. Side Wall Rear Wall R.H. Side Wall SMART Flux Sensor 16
Design Online-Cleaning System: Realisation Water Cannons installation SMART Flux Sensor 17
Example 2 The situation SMART Clean for 350 MW hard coal tower type boiler Uncontrollable slagging and fouling Erosion of heat exchangers Interruption during boiler operation Costs of maintenance Boiler cleaning following fixed time criteria 18
Example 2 The solution Diagnostics SMART Flux sensors in the furnace SMART Gauge sensors in the convective area Analysis SMART Furnace SMART Convection Thermodynamic modelling (TDM) Matrix Clean Decision CLEANING MANAGER = selected SMART Clean module Activation of suggest cleaning actions corresponding to defined priorities 19
SMART Clean - Diagnostics Main beam SMART Gauge Sensors Hanger rod Subcarrier Hanger rod Collector Supporting tube 20
SMART Clean - Analysis 21
Example 2 Achieved results SMART Clean avoids increase of boiler off gas temperature (which is 25 C without SMART Clean after 3 month boiler operation) 35% reduction of cleaning operations, 40% reduction of steam consumption Reduction of erosion on heat exchanger bundles Prevention of unscheduled boiler shut downs uncontrolled deposit 22
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