Once through sliding pressure steam generator
AssigneeCombustion Engineering, Inc.
InventorDavid Palchik
Life of this patent
Estimating the term…
Abstract
A once through steam generator (10) for sliding pressure operation from supercritical pressure at high loads into the subcritical range at low loads, having vertical tubes (14) lining the furnace (12) walls and passing their entire length without a mixing header. The furnace tubes are internally rifled and have orifices (47) associated with them to proportion the flow at full load. A steam separator (26) receiving effluent from the tubes sends steam to the superheater (70) and at low ratings returns water (32,40) to the tubes for recirculation therethrough. The tubes (14) are sized in accordance with a specified criteria based on the mass flow rate at full load, or on the ratio of friction drop to static head.
Claims28
A supercritical pressure once-through type steam generator for sliding pressure operation into the subcritical pressure range at reduced loads, comprising:
- control means for operating said steam generator at supercritical pressure at high loads and at subcritical pressure at low loads;
- a furnace;
- vertical tubes lining the walls of said furnace around the periphery thereof, said tubes in parallel flow arrangement and continuous throughout the height of said furnace;
- internal flow agitating means located within said tubes throughout substantially the entire heated length thereof;
- a steam-water separating means;
- means for conveying fluid leaving said tubes to said separating means;
- a superheater;
- means for conveying steam from said separating means to said superheater;
- means for selectively directing substantially the entire flow of fluid leaving said tubes through said superheater;
- feedwater supply means;
- means for conveying feedwater to said tubes;
- means for passing a flow through said tubes exceeding the flow through said superheater during very low load operation of said steam generator;
- and fixed means for apportioning flow to various of said vertical tubes in proportion to the predicted full load heat absorption of the various tubes.
A supercritical pressure once-through type steam generator for sliding pressure operation into the subcritical pressure range at reduced loads, comprising:
- control means for operating said steam generator at supercritical pressure at high loads and at subcritical pressure at low loads;
- a furnace;
- vertical tubes lining the walls of said furnace around the periphery thereof, said tubes in parallel flow arrangement and continuous throughout the height of said furnace, and internally rifled throughout a substantial heated length;
- a steam-water separator;
- means for conveying fluid leaving said tubes to said separator;
- a superheater;
- means for conveying steam from said separator to said superheater;
- means for selectively directing substantially the entire flow of fluid leaving said tubes through said superheater;
- feedwater supply means;
- means for conveying feedwater to said tubes;
- means for conveying water from said separator to said tubes;
- pump means for recirculating water through said tubes from said separator during very low load operation of said steam generator;
- and orifices for apportioning flow to various of said vertical tubes in proportion to the predicted full load heat absorption of the various tubes.
A once-through type steam generator for sliding pressure operation in the subcritical pressure range, comprising:
- a furnace;
- vertical tubes lining the walls of said furnace around the periphery thereof, said tubes in parallel flow arrangement and continuous throughout the height of said furnace;
- internal flow agitating means located within said tubes throughout substantially the entire heated length thereof;
- a steam-water separating means;
- means for conveying fluid leaving said tubes to said separating means;
- a superheater;
- means for conveying steam from said separating means to said superheater;
- means for selectively directing substantially the entire flow of fluid leaving said tubes through said superheater;
- feedwater supply means;
- means for conveying feedwater to said tubes;
- means for passing a flow through said tubes exceeding the flow through said superheater during very low load operation of said steam generator;
- fixed means for apportioning flow to various of said vertical tubes in proportion to the predicted full load heat absorption of the various tubes;
- and the size and spacing of said vertical tubes being such that the mass flow of water entering said tubes at full load and measured in kilograms per second per meter squared is less than d+5 divided by 0.0125 where d is the inside diameter of the tube measured in millimeters.
A supercritical pressure once-through type steam generator for sliding pressure operation into the subcritical pressure range at reduced loads, comprising:
- control means for operating said steam generator at supercritical pressure at high loads and at subcritical pressure at low loads;
- a furnace;
- vertical tubes lining the walls of said furnace around the periphery thereof, said tubes in parallel flow arrangement and continuous throughout the height of said furnace;
- internal flow agitating means located within said tubes throughout substantially the entire heated length thereof;
- a steam-water separating means;
- means for conveying fluid leaving said tubes to said separating means;
- a superheater;
- means for conveying steam from said separating means to said superheater;
- means for selectively directing substantially the entire flow of fluid leaving said tubes through said superheater;
- feedwater supply means;
- means for conveying feedwater to said tubes;
- means for passing a flow through said tubes exceeding the flow through said superheater during very low load operation of said steam generator;
- fixed means for apportioning flow to various of said vertical tubes in proportion to the predicted full load heat absorption of the various tubes;
- and wherein at full load, the frictional pressure drop through said vertical tubes is less than 4 times the static head of the fluid in said tubes.
Dependencies are inferred from the claim text.