Radiotracer investigations in aniline production reactors

Radiotracer investigations were carried out to measure the residence time distribution (RTD) of the heat transfer medium (HTM) in two identical aniline production reactors. One was operating abnormally while the other functioned normally. Investigations were carried out to identify the cause(s) of inadequate heat transfer from the tube-side to the shell-side of the abnormally operating reactor. For measuring the RTD of the HTM in the shell-side of the reactor, 82Br as paradibromobenzene was used as a tracer. The analysis of the measured RTD data revealed that about 60% of the shell-side volume of the abnormally operating reactor was fouled/dead, this being the root cause of the inadequate heat transfer. The modelling of RTD data indicated undesired parallel flow streams in the shell-side of the abnormal reactor. Shutdown of the abnormally operating reactor was instituted to allow remediation, fouling subsequently being visibly confirmed. The planned shutdown resulted in reduction in downtime, with substantial economic benefit to the industry.