Department of Chemical & Process Engineering The high pressure interactions of coal with CO 2 Implications for CO 2 disposal and CH 4 displacement from coal seams Mojtaba Mirzaeian Supervisor: Professor Peter.J.Hall By :

Department of Chemical & Process Engineering INTRODUCTION   Coal is the most abundant fossil fuel and the world depends heavily on it and will continue to do so for years to come.   There is overwhelming evidence for a gradual build up of atmospheric CO 2 levels and strong evidence that this is contributing to global warming.   Unminable deep coal seams are attractive as options for the permanent sequestration of CO 2

Department of Chemical & Process Engineering   Field tests are expensive and a set of laboratory tests to screen coals is needed to:   Determine the irreversible storage capacity.   Measure how tightly bound CO 2 is to different coals.   Determine the physical state of CO 2 in coal. OBJECTIVES   Which coals are most effective for sequestration?

Department of Chemical & Process Engineering   A variety of Experimental techniques have been used :   Differential scanning calorimetry   Phase change in high pressure CO 2   Irreversible sorption capacity   Thermodynamics   Temperature programmed desorption   Binding energy of CO 2   Small angle neutron scattering   Physical state/location of CO 2 in structure Experimental

Department of Chemical & Process Engineering DSC results Glass transition in coal:

Department of Chemical & Process Engineering DSC results

Department of Chemical & Process Engineering Evidence for plasticisation of Coal by CO 2. DSC results

Department of Chemical & Process Engineering DSC results Irreversible strong interactions of coal with CO 2

Department of Chemical & Process Engineering Thermodynamic of coal/CO 2 interactions DSC results

Department of Chemical & Process Engineering CO 2 desorption from coal is an activated process. CO 2 desorption from coal follows a first order kinetic model. TPD-MS results

Department of Chemical & Process Engineering TPD-MS results Desorption characteristics of CO 2 from Pittsburgh #8 coal

Department of Chemical & Process Engineering SANS results Decrease in scattering intensities after loading with CO 2 gives evidence that CO 2 can access to entire pores in coal. No change in scattering intensities with time shows that CO 2 can not diffuse through the coal matrix in the time scale of experiment.

Department of Chemical & Process Engineering   Coal/CO 2 interactions are strong and irreversible. Conclusions   The values of energy of Coal/CO 2 interactions decrease with increase in coal rank suggesting low rank coals are better for CO 2 sequestration.   CO 2 causes significant plasticisation effect in coal and changes coal structure.   CO 2 desorption from coal is an activated process and follows a first order kinetic model.   Coals offer an attractive means for the long term sequestration of CO 2.

Department of Chemical & Process Engineering Thank-You&Questions