Heat recovery system and method
AssigneeDoosan Babcock Energy America LLC
InventorRupert Mark Harrison
Life of this patent
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Abstract
A system providing for heat recovery from exhausted flue gas in a steam generator is described comprising a flue gas outlet conduit defining a flow path for flue gas from a flue gas outlet of a steam generator to a flue gas conduit junction point; a flue gas primary conduit defining a flow path for flue gas from the junction to a primary air preheater; a flue gas secondary conduit defining a flow path for flue gas from the junction to a secondary air preheater; wherein a steam generator process fluid heat exchanger is disposed within the flow path of the flue gas primary conduit upstream of the primary air preheater to recover some heat from the flue gas in advance of the primary air preheater. A method implementing the flow principles embodied in such a system is also described.
Claims22
A system providing for heat recovery from exhausted flue gas in a pulverised coal fired steam generator comprising:
- a flue gas outlet conduit defining a flow path for flue gas from a flue gas outlet of a steam generator to a flue gas conduit junction point whereat the outlet conduit splits into a primary flow path and a secondary flow path;
- a flue gas primary conduit defining a flow path for flue gas from the junction to a primary, coal pulveriser air preheater,
- a flue gas secondary conduit defining a flow path for flue gas from the junction to a secondary, combustion air preheater;
- wherein a steam generator process fluid heat exchanger is disposed within the flow path of the flue gas primary conduit upstream of the primary air preheater to recover some heat from the flue gas and to cool the primary flue gas stream in advance of the primary air preheater;
- and
- wherein there is no tempering air source supply into the primary air stream.
A steam generation system comprising a pulverized coal fired boiler and a flue gas heat recovery system in accordance with any preceding claim.
A heat recovery method for recovering heat from exhaust flue gases of a pulverised coal fired steam generator comprising the following steps:
- dividing flue gas exhausted from a steam generator into two streams;
- causing a first stream to feed into a primary, coal pulveriser air preheater;
- causing a second stream to feed into a secondary, combustion air preheater;
- wherein the flue gas stream feeding into a primary air preheater is first cooled by heat exchange with a steam generator process fluid stream;
- and
- wherein there is provided no tempering air source supply into the primary air stream.
A method of modification of a heat recovery system for a pulverised coal fired steam generator having a primary flue gas exhaust stream supplying a primary air preheater and a secondary flue gas exhaust stream supplying a secondary, combustion air preheater, the method comprising providing a heat exchanger in the primary flue gas exhaust stream upstream of the primary air preheater to cool primary air by heat exchange with a steam generator process fluid, wherein there is no tempering air source supply into the primary air stream.
Dependencies are inferred from the claim text.