Projects
CBM - Char Bed Modernization
Why Modernize Primary Air Systems?
Liquor droplets dry & burn faster in suspension
Fluidize char bed speeds spray to smelt conversion.
Generates higher thermal inertia to allow more (fuel) liquor spray downwards.
Molten droplets are less buoyant with higher density that reduces carryover.
Low benefit large char beds shields much of the fuel below the surface of the bed.
A hot and low char bed has greater disturbance rejection capability.
Reducing conversion time from char to smelt adds greater safety and throughput capability.
What do you get from SHB’s CBM:
Improved emissions and carryover.
Control complete bed topography.
Maintain hotter char bed.
Eliminate the formation of concentrated flue gases at the center of the furnace.
Improve disturbance rejection capability.
Improve boiler water circulation ratio
We have achieved the contract established goals on 100% of our projects.
Existing primary air systems are out of date and the costs of operation and maintenance are very high. The original purpose of the primary air was to provide a smelt drainage path around the perimeter of the bed. The days of 52% to 63% liquor solids firing created high tendency to blackouts, where many close-space openings were needed to gain access to stoke the bed with manual rods. These conditions no longer exist today.
Today, with much higher solids concentration in the black liquor and much larger furnaces the result is higher temperatures in the lower furnace than what existed during the early stages of chemical recovery boilers. The CBM system can increase the bed temperature and improve the char bed profile such that the overload on the boiler can be safely secured. The carryover or boiler plugage can be reduced because more liquor spray is pushed to the bed and the boiler water circulation ratio can be increased with a hotter bed
This One Tree Somewhere
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