Calcium Fouling in Barometric Leg of a Direct-Contact Condensor


Calcium Fouling in Barometric Leg of a Direct-Contact CondensorWe were recently out at a customer’s site, where we had been contracted to replace an existing fully integrated and original steel barometric direct-contact condenser with a new stainless-steel material direct-contact condenser. We made an amazing discovery. After 60 years of operating the evaporator, the barometric leg discharging out of the condenser formed many layers of calcium fouling. The extent of these layers was close to 2 inches of calcium layering in a 12-inch diameter pipe. That is a reduction of the cooling water line opening of 55%.

The customer had to drain the cooling water out of the system every day because they had to break the vacuum during their Cleaning in Place (CIP) of the falling film evaporator system. The chemicals used for CIP would have destroyed the steel piping. For that reason, the vacuum and condensing of the boiling vapors into the cooling water would have corroded the steel components in the cooling water loop. Refilling the cooling water system every day with untreated water created the largest calcium layer I had ever seen. In the daily operation, it came to times where the customer had to turn the cooling water flow down to avoid flooding of the condenser; under those conditions, the cooling water will flow back into the product, which is unacceptable. Nobody expected the calcium layer to be this thick.

Calcium Fouling in Barometric Leg of a Direct-Contact Condensor

We replaced the barometric condenser and included a vapor valve to isolate the cooling water system (partly constructed out of steel materials) and the falling film evaporator system, so the customer can CIP under vacuum conditions.

This meant that our customer:

  1. Can keep the cooling water system full, no daily draining and replacing of the cooling water required.
  2. Did not have to wait to brake and pull vacuum anymore, which saved them an hour of downtime every day.
  3. Got a higher throughput in the summer months. By installing a new barometric leg with a full-bore opening, the cooling water flow is no longer limited to the cooling water return line’s true inner diameter.

Overall, another interesting project, and we have given the customer a good return on their investment, plus the evaporator has been upgraded for years to come.

Contact us for more information when your installation has these or any other kind of issues.

Jan de Geest
Evaporator Woes - Vacuum Control, Velocity, and Carryover

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