Desulphurisation

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Desulphurisation

• Hemant Pandit, Ranjan agrawal

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Wet Flue Gas Desulphurisation

• The wet FGD process
• CaCO3(s) SO2(g) 2H2O ½O2 ? CaSO4?2H2O(s)
  CO2
• Major reactions (Kiil, 1998)
• ? Absorption of SO2
• ? Oxidation of HSO3- to SO42-
• ? Limestone dissolution
• ? Gypsum crystallisation
• Important parameters
• ? Desulphurisation degree
• ? Gypsum moisture content
• ? Gypsum impurity content (limestone etc.)

Courtesy of DONG Energy
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The oxy-fuel concept
Oxy-fuel combustion ? Substitution of fuel air
with oxygen ? Flue gas recycle in order to
control temperature/convective heat transfer ?
Gas phase enriched in CO2 H2O ? Capture and
compression of CO2 Flue gas desulphurization ?
Ensuring a clean product i.e. transport and
geological storage considerations ? Wet FGD
before compression (traditional) ? As part of
the compression (research stage)
Courtesy of Vattenfall
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Fuel Processing
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Fuel Processor
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Gasification of solid fuels
Moving bed Fluidized bed Entrained bed
Generic Types
Second generation
BGL Shell Texaco KRW
HT Winkler and many more
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• Partial Oxidation
• CxHy x/2 O2 x CO y/2 H2
• Advantages
• Any type of hydrocarbon
• Direct Heat transfer
• Disadvantages
• Low H2 production
• Dilution of gas with N2
• Soot formation

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• Desulphurisation
• Gas phase Desulphurisation
• ZnO H2S ZnS (s) H2O (g)
• 2 to 3 kg ZnO sufficient for one year
  Automobile operation
• Liquid Fuel Desulphurisation
• Gasoline 30-40 ppm 1-2ppm Sulphur
• For high sulphur Fuels hydro treatment
  followed by gas phase
• Desulphurisation

Adsorption
Chemical reaction
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Conclusions

• Presently liquid fuels like gasoline Diesel
  which
• contain high aromatic content and sulfur
  are not
• very suitable for on board applications.
• Availability of Methanol Ethanol for fuel
  uses are
• inadequate.
• For use of natural gas economic and
  environmental
• benefits are to studied in detail.
• A multi fuel Reformer needs to be developed
  (For
• fuels with small range of C/H ratio).
• Thrust areas for RD
• Development of reactors/separators (Membrane)
• Indigenous Catalyst development