Integrated Approach to CO2 Capture: Fuel Gas Decarbonisation

AbstractIn this presentation, the opportunities for pre-combustion capture of fuel gas at a world-scale manufacturing complex will be evaluated. The work focusses on decarbonising fuel gas at a central location in a manufacturing complex to create a hydrogen rich fuel gas pool ready for use in existing or slightly modified heating equipment and a high pressure CO2 stream ready for storage. Evaluations are based on current reforming and gasification technologies in combination with available gas treating line-ups, as well as new line-ups with emerging gas separation technologies, like high temperature membranes. Dependent on the local process boundary conditions (sweet or sour fuel gas) one or more technologies can be suitable. Current conclusion is that the concept of pre- combustion capture at a world scale manufacturing location is feasible with available technologies.It is advised to demonstrate at a scale which is sufficiently large to evaluate the performance and reliability of the individual technologies as well as the complexity of integration with the manufacturing. This presentation will reveal some of the technology aspects regarding the minimum scale for a demo regarding membrane technology.Several membrane based process schemes have been short listed for these fuel decarbonisation demonstration projects. Recovery of CO2 at high pressure and high purity (>90 mol%) as well as carbon conversions in excess of equilibrium limits may be achieved using various process schemes patented by Shell [1,2].Successful evaluations of CRI/Criterion H2 separation membranes in membrane steam reformers and as high temperature membrane separators have been performed by CRI/Criterion [3]. These membranes can be produced with a hydrogen permeance in the range of 50-70 [Nm3/m2.h.bar0.5]. Both the hydrogen flux and the separation selectivity are stable at temperatures of 300 - 500 oC and large differential pressures (tested up to 68bar). H2 purity of >99% has been demonstrated for long periods (over 1 year) in high temperature gas separations