MEASUREMENT OF RESIDENCE TIME DISTRIBUTION BY LASER-ABSORPTION SPECTROSCOPY

The residence time distribution (RTD) was obtained in a tubular reacto r with mean residence times of the order of milliseconds by using an i nfrared laser absorption technique. The reactor was operated at room c onditions with a nitrogen or helium gas flow, the tracer used was meth ane. The fast response of the measuring device allowed a qualitative a nalysis of the micromixing in the flow. An axial dispersion model was used to describe the RTD of the reactor. It was found that the values for the dispersion coefficient were strongly influenced by the radial velocity profile in the reactor.