Direct Contact Inc. (DCI) Heat Recovery Vessels have two configurations: single and dual chamber. If the flue or vent stream is relatively 'clean' or if particulate matter does not have an adverse effect on the contact water quality, then a single chamber vessel is used. If particulate loading is heavy, or the particulate will degrade the contact water, then a dual chamber vessel is used. The first chamber of the dual chamber vessel is the vapor-conditioning chamber, where the gases are adiabatically cooled and particulate is removed from the gas. The vapor-conditioning chamber combines cyclonic action and particle growth via condensation to remove contaminants, and works especially well for hygroscopic particles. In a single chamber vessel the vapor is conditioned and heat is recovered in the same chamber.

The patent-pending DCI Heat Recovery Vessels generate a controlled stream of water/liquid droplets and contacts them with hot flue or vent gases. The small droplets have a tremendously large collective surface area, which can efficiently transfer heat; heat transfer coefficients are roughly an order magnitude larger than those achieved by traditional indirect heat exchangers. The direct contact heat transfer surfaces of the spray droplets are continuously regenerated and never foul, while the pressure drop developed through the vessel is significantly lower than that of solid surface exchangers.

DCI Heat Recovery Systems are designed to remain “transparent" to the process, thereby not affecting operations sensitive to backpressure and allowing for periodic maintenance and inspection without requiring process downtime.