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US 9,587,828 B2Granted
Localized flue gas dilution in heat recovery steam generator
AssigneeSiemens Aktiengesellschaft
InventorsZaher El Zahab, Gerald J. Feller
Life of this patent
Estimating the term…
Abstract
A heat recovery steam generator (HRSG) (10) including: an economizer (12) configured to heat a working fluid by extracting heat from a flow of flue gas (20). The HRSG includes a diluting fluid injector arrangement (60) configured to inject a diluting fluid (50) effective to dilute a concentration of a gaseous corrosive when compared to an undiluted concentration of the gaseous corrosive in the flow of flue gas. The HRSG also includes a preheater (18) configured to preheat the diluting fluid prior to injection.
Claims19
An HRSG, comprising:
- an economizer configured to heat a working fluid by extracting heat from a flow of flue gas, the economizer comprising a heat exchanger tube comprising a surface portion and a diluting fluid injector arrangement configured to inject a diluting fluid effective to create a diluted volume within the flow of flue gas, the diluted volume at least partly separates an undiluted volume flow of flue gas from the heat exchanger tube, the sulfuric dew point of the diluted volume is lower in comparison to the undiluted volume, wherein a portion of the economizer extracts heat from undiluted flue gas, and a portion extracts heat from the diluted volume;
- and
- a preheater configured to preheat the diluting fluid prior to injection.
An HRSG, comprising:
- a flue duct;
- a heat exchanger disposed in the flue duct and comprising a heat exchanging element configured to provide thermal communication between a first fluid flowing in the flue duct and a second fluid flowing in the heat exchanging element;
- and
- an injector arrangement configured to inject a diluting fluid into the flue duct adjacent a shell side of the heat exchanging element, the injector arrangement effective to dilute some, but not all, of the first fluid, the diluted first fluid flow separates the heating exchange element from the undiluted first fluid flow such that forming liquid sulfuric acid on the heating exchange element is avoided, the diluted first fluid flow has a sulfuric dew point different than the undiluted first fluid flow.
1 more element
A method of operating a HRSG, comprising:
- receiving a flue gas comprising an undiluted gaseous corrosive in a duct;
- flowing a working fluid through a heat exchanger in the duct, the heat exchanger effective to permit heat transfer between the flue gas and the working fluid;
- transferring heat from the flue gas comprising the undiluted gaseous corrosive and disposed within the heat exchanger;
- diluting the undiluted gaseous corrosive using a diluting fluid injector arrangement disposed within the heat exchanger to form a first volume within the flue gas comprising a diluted gaseous corrosive, wherein the first volume at least partially separates a first portion of a surface of the heat exchanger from the flue gas comprising the undiluted gaseous corrosive, the first portion characterized by a temperature below a dew point of the undiluted gaseous corrosive and above a dew point of the diluted gaseous corrosive;
- and
- transferring heat from the volume comprising the diluted gaseous corrosive within the heat exchanger.
3 more elements
Dependencies are inferred from the claim text.