CIP Heat Exchangers
Clean-in-Place Heating

CIP Heat Exchangers

Heating Clean-in-Place Solutions to Setpoint

A CIP circuit brings caustic, acid, sanitizer and rinse water to setpoint and holds them there while solution recirculates through the process equipment being cleaned. The exchanger doing that heating is in the circuit, which means it sees every chemical the plant uses, hot, over and over again.

Ramp rate is the commercial driver, not energy. Once solution is at setpoint the standing heat load is small. What matters is how quickly the tank reaches temperature, because that time is production time lost. CIP heaters are therefore sized for heat-up rate rather than for hold duty, and undersizing one to save capital cost is usually a poor trade against the changeover time it adds every single day.

Chlorinated sanitizers are the alloy problem. Caustic at temperature is straightforward in 316L. Acid cycles are manageable. What catches austenitic stainless is chlorinated sanitizer, because chlorides plus temperature plus the residual tensile stress at a U-bend is precisely the recipe for stress-corrosion cracking. Where a chlorinated sanitizer is part of the cycle, that frequently moves the recommendation to duplex, and it is far cheaper to make that decision once than to replace a cracked bundle twice.

Tell us the full cycle, not the product. The most useful information for a CIP heater is the complete sequence: which solutions, at what concentration, at what temperature, for how long, and in what order. That sequence is a more aggressive service than most of the product the circuit cleans up after, and it is what the alloy has to survive.

The exchanger has to clean itself. Because it sits in the circuit it needs the same drainability, the same crevice-free construction and the same absence of dead legs as any product-contact equipment. Seal-welded tube joints, sloped shells, low-point drains and sanitary connections are all specified for the exchanger's own cleanability rather than only for the product it eventually helps make.

Single tank or multi-tank. Single-tank sets reuse solution and are simpler; multi-tank sets hold caustic, acid and rinse separately and change over faster. The exchanger sizing follows the arrangement, and on multi-tank sets it also has to handle the transition between chemistries without carryover.

Related pages: sanitary U-tube exchangers, culinary and clean steam, duplex and high alloys and tri-clamp connections.