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The Centre for Process Innovation (CPI) is a center of excellence based in North East England. CPI's Advanced Processes Division chose METTLER TOLEDO sensors for their excellent performance and reliability.

Continuous flow baffled reactor
The production of fine and speciality chemicals predominantly employs multi-stage batch processing techniques as the method of manufacture. Stirring of batch reactions is not necessarily the best method for mixing reactants efficiently or for maximizing yields, nor is it an efficient use of time. A continuous reactor can maximize yields, and provide a more compact plant than batch processes can. Mixing in a continuous reactor is usually achieved in the tube through the use of baffles. The baffles cause the fluid to form vortices and the motion of the fluid in the vortices results in efficient and uniform mixing.

Expert help and advice
A recent research project at CPI called for pH and dissolved oxygen (DO) measurements in three locations along the length of a continuous reactor, which was to be constructed from 2" (5.08 cm) diameter jacketed glass tube. Getting sensors into such a process was proving problematic for CPI and they approached METTLER TOLEDO for help.

After many in-depth discussions between METTLER TOLEDO, CPI and the glass manufacturer, agreement was reached on a design for a polymer collar which would fit between the flanged sections of the glass reactor and allow the sensors to enter the process at the correct angle without restricting flow through the tube.

The sensors were mounted in the collars via a 1" (2.54 cm) screw thread using METTLER TOLEDO InFit761 housings, which allow easy insertion of sensors.

Advanced processes require advanced sensors
InPro3250SG pH electrodes were selected as they were best suited to the wide range of processes which would take place in the reactor. Their integral solution ground allows simultaneous measurement of pH and ORP as well as real-time, advanced sensor diagnostics.

Due to their reliable performance under the harshest of process conditions, InPro6800 DO sensors were chosen for the application. The easy to change membrane body reduces sensor maintenance to a five minute procedure, increasing sensor availability.

M300 transmitter

As this was a research project, simple, reliable and cost effective transmitters were required. Three dual-channel M300 transmitters were used to handle a total of six in-line measurements and to output the readings for data logging.

Denis Wray, Senior Process Technologist at CPI
"I have been impressed by METTLER TOLEDO's help and commitment in bringing projects to fruition here at CPI. Their advice and after sales service have, in my opinion, been exemplary."

SOURCE: Mettler-Toledo AG, Process Analytics, Inc.