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Fuel Tech Chemical TechnologiesRECOVERY CHEM®

Comprehensive Fireside Slag and Fouling Control Programs for Black Liquor Recovery Boilers


The design and use of black liquor recovery boilers has caused a significant boost in efficiency and a reduction in pollution over the past several decades. Changes in market conditions have led to boiler design modifications in order to achieve higher solids in the black liquor, which can be problematic for boiler operators. Conventional fuel treatment programs attempt to reduce slagging, fouling, erosion and slag falls by injecting reagents into the liquor or the salt cake tank or blowing it into the furnace adjacent to tertiary air ports. Most problem areas receive minimal treatment; typically these programs are not economical and result in poor performance.

Operational Benefits to Black Liquor Recovery Boilers:

  • Reduces fireside deposition, erosion and corrosion problem areas
  • Reduces slagging and fouling
  • Reduces shut downs, resulting in significant ROI

RECOVERY CHEM targets problem areas of recovery boilersHow It Works

RECOVERY CHEM® programs reduce fireside deposition, erosion and corrosion problems by application of a comprehensive treatment plan. Our programs enhance mechanical removal mechanisms by targeting the reagent at the problem areas of the radiant and convection sections, while ensuring adequate reaction times. This allows efficient boiler operation and can help mitigate deposits.

After gaining a thorough understanding of a customer’s needs, a problem analysis is conducted. This includes the collection of unit operating and boiler design data and deposit samples. Our proprietary computational fluid dynamics (CFD) computer modeling and data visualization processes are then used to generate a boiler-specific program. Our engineers study these models to identify the placement of injectors resulting in the most efficient arrays to meet performance requirements.

These results are used to generate process design, equipment design, specifications, layout, predicted program performance, program cost and return on investment (ROI).

Program Design:

Comprehensive survey of boiler

  • Design parameters
  • Furnace geometry
  • Mass inputs
  • Operating practice

CFD Model: In Furnace View

  • CFD model data set exported to virtual reality engine
  • Temperature profiles and gas flows determined, injector placements are selected
  • Manipulation of injector location, spray characteristics, droplet size, droplet velocity
  • Data is used to design injection strategy for maximum coverage

Program Application:

  • Stabilized magnesium hydroxide is received in bulk trucks and is transferred into the bulk tank by plant operators. The chemical is recirculated through a heat exchanger and then on to chemical metering pumps.
  • Chemical is pumped to the boiler injectors using a custom made pump and control system. The pumps feed chemical to the injectors on the appropriate boiler floor level. A water booster pump is provided for reliable chemical injection performance.
  • The chemical program is then injected into the fireside of the boiler at specific locations based on the CFD model of the boiler.

Chemical Technologies Programs

  • TIFI®
    Targeted In-Furnace Fuel Injection
  • HClear®
    HCl Abatement Programs
    Slag and Fouling Control for Black Liquor Recovery Boilers
  • Redox-Hg
    Enhanced Mercury Removal for Wet FGD Scrubbers
  • TIFI Bio™
    Slagging and fouling control for biomass flexible fuel units