[Case study] Organic chemistry: reheating and cooling of a pressurized loop on a reactor.

An International chemical group equipped itself with Barriquand tubular heat exchangers for overheated water applications on reactors with thermomechanical constraints (pressure, temperature, variability) and important reliability requirements.

Heat exchangers for chemical reactions
Specialized in the production of additives for industrial paints, this industrialist uses exothermic reaction processes. The latter are carried out in reactors equipped with serpentines or with double – walls fed by an overheated water circuit which requires the intervention of 2 heat exchangers: a heater upstream, a cooler downstream.

The water which is pressurized at 30 bar is heated to 170°C to enable the chemical reaction. It is recovered at 200°C and must then be cooled.

Stringent thermomechanical submissions
The clients’ project had 2 objectives:

To replace, on an existing reactor, 2 heat exchangers with semi-welded plates which presented leaks.
To install 2 new heat exchangers of the same technology on an additional reactor.The main constraint inherent to the process is in the thermal shocks engendered by the temperature cycles. Indeed, the 2 cold heat exchangers are designed to receive strongly pressurized water in high and variable temperatures (160 / 200°C, calculation up to 300°C) 4 times a day (Every reaction lasts 5 / 6h, there are 4 reactions a day).

Consequently, they are subjected to important and sudden dilations and therefore a high risk of leaks, which was the case on the previous heat exchangers.

More reliable heat exchangers adapted to cyclic functioning
We supplied our client with U-bend tubular heat exchangers, made in France at our ASET workshop in Saint-Priest (Auvergne-Rhône-Alpes Region).

Besides presenting reduced dimensions which makes their installation easy in an existing location, these very robust devices offer an excellent resistance to variability and to thermal shocks.

Each tube can freely dilate whereas the bundle is welded and crimped to the calandria along the whole of its periphery which makes it totally seamless, ruling out any risks of leaks and producing an extremely reliable and long-lasting exchanger.

Identical thermal performances, less maintenance
Installed 1 year ago, the 4 heat exchangers comply with the thermal specifications and require a level of maintenance reduced to the bare minimum, which limits the devices’ downtime to 12 or 24 hours, in case of an intervention.

A real gain for our client whose installations work continuously and for whom each production stop represents a very important financial loss.

Satisfied with the reliability of our tubular heat exchangers our client has since entrusted us with new projects.

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