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US 7,815,889 B2Granted
Method and apparatus for pressurized calcination of gypsum
AssigneeUnited States Gypsum Company
InventorsWenqi Luan, Qingxia Liu
Life of this patent
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Abstract
A method for calcining gypsum in a pressurized reactor by injecting combustion gases and air into the pressurized reactor to create a fluidized bed of gypsum, and heating the fluidized bed of gypsum in the pressurized reactor sufficiently to form a calcined hemihydrate.
Claims5
A method for calcining gypsum comprising:
- injecting gypsum into a pressurized reactor;
- injecting combustion gases and air into the pressurized reactor to create a fluidized bed of gypsum in the reactor;
- and heating the fluidized bed of gypsum in the pressurized reactor to sufficiently calcine the gypsum to form a calcined hemihydrate;
- combusting fuel and air in a burner to create the combustion gases;
- diverting a portion of the combustion gases to the pressurized reactor to create the fluidized bed;
- and directing a remaining portion of the combustion gases to a heat exchanger used for heating the fluidized bed.
3 more elements
A method for calcining gypsum comprising:
- injecting gypsum into a pressurized reactor;
- injecting combustion gases and air into the pressurized reactor to create a fluidized bed of gypsum in the reactor;
- and heating the fluidized bed of gypsum in the pressurized reactor to sufficiently calcine the gypsum to form a calcined hemihydrate;
- wherein the heating is accomplished with a heat exchanger and wherein the method further comprises removing the calcined gypsum from the pressurized reactor and heating the calcined gypsum with a second heat exchanger.
1 more element
A method for calcining gypsum comprising;
- continuously injecting gypsum into a pressurized reactor;
- heating the gypsum to form a calcined hemihydrate with a lower water demand hemihydrate, the calcined hemihydrate having a water to stucco ratio in the approximate range of 0.45-0.55;
- and moving the dried calcined hemihydrate from a second heat exchanger through a discharge valve into a heated mill which simultaneously heats and grinds the calcined hemihydrate.
An apparatus for continuously calcining gypsum comprising at least one gypsum hopper having a hopper inlet and a hopper outlet;
- said hopper outlet being in communication with a continuous meterin device pressurized reactor in communication with said continuous metering device wherein the pressurized reactor includes an adjustable speed double screw counter-rotating auger having hollow shafts and hollow blades that is disposed within the pressurized reactor to continuously heat and convey a fluidized bed of gypsum from an inlet of said reactor to an outlet of said reactor.
Dependencies are inferred from the claim text.