High resolution gamma ray tomography and its application to the measurement of phase fractions in chemical reactors

We applied gamma ray tomography to the problem of phase fraction measurement in chemical reactors. Therefore, we used a new tomography device that is operated with a Cs-137 source and a high resolution gamma ray detector. One application example is the reconstruction of the fluid distribution and the measurement of radial gas fraction profiles in a laboratory scale stirred vessel. The tomograph was used to obtain radiographic projections of the averaged gamma ray attenuation for different stirrer speeds along the height of the vessel. With tomographic reconstruction techniques we calculated the angularly averaged radial distribution of the attenuation coefficient for as many as 150 single cross-sectional planes and synthesised from this data set the axial and radial fluid distribution pattern. Further, we exemplarily reconstructed the radial gas fraction distributions induced by the stirrer in the area of the stirrer blades. In a second application the gamma ray measurement system was used to visualise gas inclusions in a water cleaning column that is used to remove hazardous heavy metal species from water.