Desulphurisation

Hemant Pandit, Ranjan agrawal

DTU Chemical Engineering Technical University of Denmark

The wet FGD processCaCO3(s) + SO2(g) + 2H2O + ½O2 → CaSO42H2O(s) + CO2

Major reactions (Kiil, 1998)

● Absorption of SO2

● Oxidation of HSO3- to SO4

2-

● Limestone dissolution

● Gypsum crystallisation

Important parameters

● Desulphurisation degree

● Gypsum moisture content

● Gypsum impurity content (limestone etc.)

CHEC Annual Day, 2009 01.10.2009

Courtesy of DONG Energy

Wet Flue Gas Desulphurisation

1

DTU Chemical Engineering Technical University of Denmark

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

The oxy-fuel concept

2 CHEC Annual Day, 2009

01.10.2009

DTU Chemical Engineering Technical University of Denmark

Fuel Processing

DTU Chemical Engineering Technical University of Denmark

Fuel Processor

DTU Chemical Engineering Technical University of Denmark

C + O2 CO2 C + H2O CO + H2

C + CO2 2COCO + H2O CO2 + H2

CO + 3H2 CH4 +H2O

Moving bed Fluidized bed Entrained bed

BGL Shell Texaco KRW HT Winkler and many more

Second generation

Generic Types

Gasification of solid fuels

DTU Chemical Engineering Technical University of Denmark

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

DTU Chemical Engineering Technical University of Denmark

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

DTU Chemical Engineering Technical University of Denmark

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 R&D

• Development of reactors/separators (Membrane)• Indigenous Catalyst development

DTU Chemical Engineering Technical University of Denmark

Desulphurization plant in Germany

DTU Chemical Engineering Technical University of Denmark

NEW MEXICO

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UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND

DTU Chemical Engineering Technical University of Denmark

UNITED STATES OF AMERICA, Louisiana

DTU Chemical Engineering Technical University of Denmark