Jet pump in natural circulation fossil fuel fired steam generator
AssigneeFoster Wheeler Energy Corporation
InventorsWalter P. Gorzegno, Juan-Antonio Garcia-Mallol
Life of this patent
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Abstract
A jet pump is provided in the downcomer of a natural circulation fossil fuel burning vapor generator to enhance circulation in the vaporizer circuits of the vapor generator. A driving fluid pump is adapted to introduce liquid taken from the drum as driving fluid for the jet pump, and the liquid passing through the downcomer acts as driven fluid for the jet pump.
Claims16
In a natural circulation fossil fuel burning vapor generator including a vapor generating circuit, said vapor generating circuit including a plurality of riser tubes arranged for passing a vaporizable fluid therethrough in heat exchange relation with hot gases, a separating drum in flow communication with outlet ends of said riser tubes for receiving said vaporizable fluid including saturated vapor and liquid, a downcomer conduit communicating with said drum and arranged to receive saturated liquid from said drum, a distributing bottle connected between the outlet end of said downcomer conduit and the inlet ends of said riser tubes, the improvement comprising:
- (a) a jet pump including a nozzle section adjacent a suction inlet end thereof, a diffuser section adjacent an outlet end thereof, and a throat section intermediate said inlet and outlet ends, said jet pump being disposed within said downcomer conduit upstream of the outlet end of said downcomer, saturated liquid flowing through said downcomer conduit acting as suction flow fluid passing into said jet pump through said suction inlet end thereof;
- (b) a driving fluid pump adapted to receive a portion of said saturated liquid from said separating drum;
- (c) means for passing said portion of said saturated liquid from said separating drum to an inlet of said driving fluid pump;
- and
- (d) conduit means connected between an outlet of said driving fluid pump and said nozzle section of said jet pump for introducing said portion of saturated liquid to said nozzle section.
In a method of operating a natural circulation vapor generator including the steps of passing a vaporizable fluid through a plurality of riser tubes in indirect heat exchange with heated gases for heating said fluid, passing said heated fluid including saturated vapor and liquid to a separating drum for separating saturated vapor from said fluid, passing saturated liquid from said drum through a downcomer conduit to a bottle disposed adjacent the end thereof, and passing said fluid from said bottle to said riser tubes, the improvement comprising the steps of:
- (a) passing a portion of said saturated liquid from said separating drum to a driving fluid pump;
- (b) pumping said portion of saturated liquid through said driving fluid pump thereby increasing the pressure of said portion of saturated liquid;
- (c) introducing said portion of saturated liquid of increased pressure into a jet pump, said jet pump being disposed within said downcomer conduit at a location upstream of the outlet end of said downcomer conduit and including a nozzle section adjacent a suction inlet end thereof, a diffuser section adjacent an outlet end thereof, and a throat section intermediate said inlet and outlet ends, said portion of saturated liquid being introduced to said jet pump through said nozzle section of said jet pump and comprising a driving flow fluid;
- (d) passing said saturated liquid flowing through said downcomer conduit into said suction inlet end of said jet pump, said saturated liquid comprising suction flow fluid;
- (e) mixing said driving flow fluid with said suction flow fluid in said throat section of said jet pump;
- (f) passing said fluid mixture to said diffuser section wherein the velocity head of said driving fluid is converted in said diffuser section into static pressure head, said static pressure of said fluid mixture being greater than the static pressure of said suction flow fluid at the location adjacent said jet pump inlet end;
- and
- (g) passing said fluid mixture to said bottle for distribution of said mixed fluid of greater static pressure to said riser tubes.
Dependencies are inferred from the claim text.