Radiotracer investigation in an industrial-scale oxidizer

•A radiotracer investigation was carried out in an industrial-scale oxidizer.•The measured data were analyzed and flow parameters were obtained.•The oxidizer behaved as an ideal stirred tank reactor.•The results of the investigation were used to design of a new oxidizer.

A radiotracer investigation was carried out in an industrial-scale oxidizer. The main objectives of the investigation were to measure residence time distribution (RTD) of organic process fluid, determine the mean residence time (MRT) and investigate the degree of axial mixing. Bromine-82 as p-dibromo biphenyl was used as a radiotracer for measuring RTD of the organic process fluid. The MRT of the fluid in the oxidizer was determined to be 390 min. An ideal stirred tank model with a plug flow reactor in recirculation stream was used to simulate the measured RTD data and was found suitable for describing flow in the system. Based on the model simulation the mean residence times in oxidizer and recycle stream were estimated. The results of the investigation showed that the oxidizer behaved as a well-mixed reactor whereas the recycle stream behaved as a plug flow reactor.