Quenchers
There are many industrial and municipal processes that generate very hot (400 DgC and higher) exhaust gas. Frequently these gases contain noxious material such as fine particles or acid vapors. These gases are best treated after they have been evaporatively cooled to their dew point typically below 100 DgC. Uncoupling the cooling process from the removal process has many advantages from performance to construction materials.
The D. R. Technology quencher design employs the same aerodynamic Venturi shape as described above. The hot gas must pass through either a circular or annular throat. The entering hot gas passes downward through a dry duct into which a horizontal removable pipe is located. Depending on external temperature requirements, the interior of the dry duct can be lined with castable refractory. There will be a wide angle spray nozzle mounted at the end of this pipe. There is a shelf at the top of the Quencher where additional liquid is added which will spin and cover the walls of the converging portion of the Quencher to avoid dry walls and solids deposition. The quenched gas then passes downward either into a diverging section for pressure recovery or for smaller units into an elbow where it turns and flows horizontally to further processing downstream.
There is a design option on the top of the Quencher which permits vertical and horizontal upstream duct growth while eliminating the need for expensive expansion joints. This design is known as a “Floating Inlet.” The inlet duct is built separately from the lower Quencher. The lower Quencher body does not have the above mentioned liquid shelf but utilizes a trough of specific interior and exterior heights. The upper duct is mounted into the trough with its very bottom typical 10 mm from the trough bottom. Circulating quench liquid is added tangentially into the shelf where it spins and overflow onto the converging section. He liquid in the trough forms a water seal vs the outside air pressure. If the outside air pressure is higher than the inside hot gas the trough wall will be higher externally than the inside wall based on the actual pressure differential. The reverse would happen if the process gas was at elevated pressure. This design is practical and cost effective at pressure differentials at or lower than 5 Kpa.
The gas being quenched frequently has corrosive contaminants present which can only be partially removed. This calls for downstream further treatment. If the contaminant is Hydrochloric acid a metal unit downstream will be very expensive. By reliably dropping the discharge gas below 100 DgC the downstream equipment can be thermoplastic like Fiberglass Reinforced Vinyl Ester. With glass filled polypropylene pacing media. D. R. Technology offers its quencher designs in a range of Stainless Steels Ni/Cr/Mo alloys and Zirconium
Absorber Thermal Oxidizer