11CO2 positron emission imaging reveals the in-situ gas concentration profile as function of time and position in opaque gas-solid contacting systems

Abstract The in situ analysis of industrial processes, mostly conducted in opaque equipment is difficult. Whereas previously the positron emission technique was successfully applied to study the flow and mixing in gas-solid and liquid-solid systems using radio-active tracer particles, research on imaging a radio- active tracer gas is scarce. The present paper demonstrates the use of a fully three-dimensional (3D) Positron Emission Tomography (PET) in imaging the adsorption of 11CO2 tracer gas, while validating the measurement by conventional exit gas analysis. It will be demonstrated that PET can be used to measure the kinetics of high-pressure CO2 adsorption in situ, including the essential breakthrough and mass transfer zone characteristics. Such high-pressure operation is characteristic of pre-combustion CO2 capturing processes. It is expected that this work will foster further studies of gas-solid systems of adsorption, gas-solid catalysis, gas-solid hydrodynamics, and processes where the gas-solid interaction is of primary importance.