Advanced flash exhaust heat recovery
First Claim
1. A system for a plant, the plant comprising a dryer operable to remove moisture from a wet cake and to produce an exhaust gas comprising water vapor, the plant also comprising a balance of plant, the system comprising:
- a boiler circuit operable to provide a first steam to the balance of the plant;
a first energy recovery circuit comprising a non-contact heat exchanger operable to extract heat from the exhaust gas and to provide a second steam, having a pressure lower than a pressure of the first steam, to the balance of plant;
a component wherein a portion of the first steam from the boiler circuit is intermixed with a flash vapor produced in the first energy recovery circuit, or a component wherein a liquid from the boiler circuit is intermixed with a liquid from the first energy recovery circuit; and
a second energy recovery circuit comprising a direct contact heat exchanger disposed downstream of the non-contact heat exchanger in a flow path of the exhaust gas, the second energy recovery circuit operable to provide a heated fluid to the balance of plant.
2 Assignments
0 Petitions
Accused Products
Abstract
Waste heat is extracted in two stages from the exhaust (20) of a biomass dryer (14) in a grain alcohol plant (10). A boiler circuit (56) provides high pressure steam to a balance of the plant (54). A first energy recovery circuit (36) extracts heat from the exhaust via a non-contact heat exchanger (24) and provides a first relatively lower pressure steam (78) to the balance of the plant, thereby bypassing a portion of the boiler circuit. Working fluids in the boiler and first energy recovery circuits are maintained within boiler water quality specifications and are intermixed to allow the production of the first relatively lower pressure steam without a pressure reduction device. A second energy recovery circuit (44) extracts heat from the exhaust downstream of the first energy recovery circuit using a direct contact heat exchanger (38) and provides a non-boiler quality heated fluid (52) to the balance of the plant.
13 Citations
11 Claims
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1. A system for a plant, the plant comprising a dryer operable to remove moisture from a wet cake and to produce an exhaust gas comprising water vapor, the plant also comprising a balance of plant, the system comprising:
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a boiler circuit operable to provide a first steam to the balance of the plant; a first energy recovery circuit comprising a non-contact heat exchanger operable to extract heat from the exhaust gas and to provide a second steam, having a pressure lower than a pressure of the first steam, to the balance of plant; a component wherein a portion of the first steam from the boiler circuit is intermixed with a flash vapor produced in the first energy recovery circuit, or a component wherein a liquid from the boiler circuit is intermixed with a liquid from the first energy recovery circuit; and a second energy recovery circuit comprising a direct contact heat exchanger disposed downstream of the non-contact heat exchanger in a flow path of the exhaust gas, the second energy recovery circuit operable to provide a heated fluid to the balance of plant. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification