Direct vs Indirect
Heat Recovery Vessels
Open vs Closed

Direct Contact LLC (DCLLC) Heat Recovery Vessels have two configurations: single- and dual-chambered. If the flue gas is relatively 'clean' or if particulate matter does not have an adverse effect on the contact water quality, then a single-chambered vessel can be used. In a single-chambered vessel, vapor is conditioned and heat is recovered in the same chamber.

However, if particulate loading is heavy or degrades the contact water, then a dual-chambered vessel is often used. The first chamber of the vessel is the vapor-conditioning chamber, where exhaust gas is adiabatically cooled and particulates are removed. This chamber combines cyclonic action and particle accumulation via condensation to remove contaminants, and works especially well with hygroscopic (literally, "water-loving") particles.

The patented DCLLC Heat Recovery Vessel generates a controlled stream of liquid droplets that are directly contacted with hot flue gas. The large surface area generated by sprays of small droplets efficiently transfers heat from the gas to the liquid. Heat transfer coefficients are over an order magnitude larger than those achieved by traditional indirect heat exchangers. The direct contact 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 heat exchangers.

DCLCC 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.