Foam Control in Delayed Coking

Foam in a coke drum can be carried into the vapor system and contribute to downstream fouling. The foam response varies with feed, cycle conditions and the way treatment reaches the foam.

The objective is a stable foam-control program within the refinery’s operating limits. Treatment decisions need to account for the downstream disposition of coker products as well as the drum itself.

Silicone-based antifoams are discussed in the source material for delayed-coking service. Their behavior at process temperature, delivery to the foam and potential contribution to silicon in coker products are related considerations.

A formulation that performs well in one coker should not be assumed to give the same result in another. Laboratory thermal behavior supports product evaluation, but it does not establish plant performance on its own.

Cestoil considers treatment selection together with the existing dilution, metering and injection arrangements. Mixing, distribution, injection reliability and the timing of treatment can affect how much material reaches the intended location.

• Feed and cycle conditions associated with foam or carryover events
• Antifoam formulation, handling properties and current delivery system
• Downstream product routing and silicon-monitoring requirements

Record foam or carryover observations, antifoam consumption and operating changes during the comparison. When silicon is monitored in product streams, keep the sampling position and point in the coking cycle consistent.

A spot sample taken during a treatment peak should not be presented as a whole-cycle average. Any proposed change should be assessed against both foam control and the requirements of downstream units.

Injection hardware and operating changes require review by the refinery team. Establish the monitoring plan and product-specific guidance before a trial. This overview does not prescribe nozzle geometry, dilution ratios or a universal treatment rate.