Patent ID: 8176655
Filing Date: 2012-05-15
Classification: B01D,F26B

Abstract:
1. A vapor atmosphere spray dryer comprising: a closed-loop circuit including a dryer, a bag house filter system, a fan, and a heater system, the dryer, the bag house filter, the fan, and the heater system fluidly connected together for circulating a mass of superheated vapor through the closed-loop circuit; a centrifugal atomizer disposed within the dryer; a feed system for delivering a supply of feed slurry to the centrifugal atomizer, the feed system operably arranged with the centrifugal atomizer for providing a supply of atomized feed slurry for combination with the circulated mass of superheated vapor within the dryer; and a powder discharge system connected to the powder outlet of the bag house filter to receive powder therefrom, the powder discharge system including a holding chamber, an upper, normally-open powder valve, a lower, normally-closed discharge valve, a normally-closed vent valve, and a control unit, the holding chamber including an upper inlet for receiving powder from the powder outlet of the bag house filter, a lower outlet, and a vent port, the normally-open powder valve operable to selectively close the inlet of the holding chamber, the normally-closed discharge valve operable to selectively open the outlet of the holding chamber, the normally-closed vent operable to selectively open the vent port of the holding chamber, the control unit adapted to periodically activate the valves in sequence such that the powder valve is in a closed position to prevent powder from entering the holding chamber, the vent valve is in an open position to allow the vapor to escape from the holdinq chamber via the vent port to bring the pressure within the holding chamber to atmospheric pressure, and then the discharge valve is in an open position to allow the powder within the holding chamber to discharge therefrom, wherein the dryer includes a superheated vapor inlet, a liquid feed inlet, and a vapor and powder outlet, the bag house filter includes a vapor and powder inlet, a powder outlet for expelling dried product therefrom, and a vapor outlet for expelling pressurized, superheated vapor therefrom, the vapor and powder feed inlet fluidly connected to the vapor and powder outlet of the dryer, the fan is fluidly connected to the vapor outlet of the bag house filter, the fan is fluidly connected to the heating system, and the heating system is fluidly connected to the vapor inlet of the dryer, and wherein the closed loop circuit is constructed such that the circulated mass of superheated vapor has an operating pressure of at least 1 psi and the operating pressure of the recirculated mass of superheated vapor is generated by the evaporation of the fluid in the atomized feed slurry in the dryer resulting from the combination of the supply of atomized feed slurry and the circulated mass of superheated vapor.