Flue Gas Cleaning

Tasks

In the European Working Group "Flue Gas Cleaning" new installations of flue gas cleaning devices are a main point of discussion. For existing devices all techniques of flue gas cleaning are dealt with at furnaces for fossil fuels, biomass and wastes. (In furnace technical measures are not generally included.)

• SO₂/SO₃ emission reduction techniques (FGD); processes: Wet, limestone/lime based, spray absorption, dry absorption, proposed new techniques
• NOx emission reduction techniques (DENOX); processes: Selective Catalytic Reduction (SCR), Selective Non Catalytic Reduction (SNCR), proposed new techniques
• Dust precipitation / separation of FGD by-products, processes: ElectroStatic Precipitation (ESP), Fabric Filter (FF), emission reduction of aerosols, of particulate matter bound heavy metals
• Emission reduction of traces like HCl, HF, N₂O, Corg + further gaseous traces by existing control equipment, and when required by further measures
• Decrease of internal energy consumption of emission reduction techniques
• Support process optimisation
• Analyse repair possibilities on cost and time requirements
• Analyse lifetime and possibilities of reactivation of components
• FGD waste water treatment aspects
• Recycling of waste water treatment sludge
• LCPD and IPPCD European and national requirements, technical realisation of legal regulations with system depending technical exceptions
• Analyse cost aspects of additional requirements
• Analyse new FGC techniques for LCPs, co-combustion of wastes in LCPs and for waste incineration plants.
• Check new process economics
• Analyse applicability of commercial available process additives
• Discuss regulation exceptions for start up, shut down and operational failure

Service

• Consulting in following areas
  - Increase reduction of environmentally significant emissions
  - Limiting risks of corrosion / deactivation of catalysts
  - Limiting by-pass flow
  - Limiting internal consumption
  - Impacts of different fuels on FGC devices
  - Interaction of FGC devices

Current Topics

• New planned and commissioned FGC devices
• Options for FGC devices with respect to Wet Stack application
• Further development of flue gas cleaning techniques for application at new power plants

Reported actual research projects

• FGD Fluid Dynamics.
  This project theoretically evaluated droplet collisions to decrease droplet size without additional nozzle pressure and increase the surface of liquid for absorption of SO2 without significant increase of liquid to gas (l/g) relation. Finished: May 2002.

• Optimised FGD nozzle distribution modelling.
  Different nozzle distributions have been simulated to reach any part of the scrubber volume in the best way. The results were very promising, and support future application on real scrubbers. Finished: End of 2004.

• Flow correlated positioning of nozzles.
  Planned is a modelling of FGD operation regarding droplet collision to reduce by-pass flows at the wall and by streak evolution. This modelling is applied to optimise positioning of nozzles in real scrubbers by a commercial CFD program.
  Start expected: Begin of 2005