US3703919A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Supplementary air cascade evaporation
Assignee: Combustion Engineering Inc
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Filing: 1970-10-22
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Granted: 1972-11-28
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Expires: 1990-10-22
Abstract
Abstract A chemical recovery unit in which black liquor from a pulping process is burned including a direct contact evaporator for concentrating the black liquor prior to its introduction into a furnace. Preheated air is used as the heating medium in the direct contact evaporator. The moisture laden air leaving the evaporator is used as secondary combustion air in the furnace.
Inventors
- 👤 Vincent P Owens
- 👤 George J Prohazka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:03
CPC Classifications
F; F23; F23G; F23G7/00; F23G7/04; D; D21; D21C; D21C11/00; D21C11/10; D21C11/103; Y; Y10; Y10S; Y10S423/00; Y10S423/03
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
147 words
A chemical recovery unit comprising in combination a furnace in which black liquor is burned, direct contact evaporation means for evaporating moisture from the black liquor prior to its introduction into the furnace, air preheater means in which air is indirectly heated by the waste combustion gases exhausted from the furnace, first air conveying duct means connecting the air preheater means to the direct contact evaporation means for conveying hot air thereto to evaporate and concentrate the liquor, second duct means for conveying the moisture laden relatively hot air from the evaporator means to the furnace to be used as secondary air for supporting combustion, and third air conveying duct means connecting the air preheater means to the lower portion of the furnace for conveying hot air directly thereto to be used as primary air for supporting combustion of the concentrated black liquor delivered to the furnace.
Claim 2
Dependent Claim
147 words
A chemical recovery unit comprising in combination a furnace in which black liquor is burned, direct contact evaporation means for evaporating moisture from the black liquor prior to its introduction into the furnace, air preheater means in which air is indirectly heated by the waste combustion gases exhausted from the furnace, first air conveying duct means connecting the air preheater means to the direct contact evaporation means for conveying hot air thereto to evaporate and concentrate the liquor, second duct means for conveying the moisture laden relatively hot air from the evaporator means to the furnace to be used as secondary air for supporting combustion, and third air conveying duct means connecting the air preheater means to the lower portion of the furnace for conveying hot air directly thereto to be used as primary air for supporting combustion of the concentrated black liquor delivered to the furnace.
Claim 3
Dependent Claim
28 words
The combination set forth in claim 1, including fourth duct means bypassing the direct contact evaporation means, and damper means located in the second and fourth duct means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-28 | 1976-05-29 | 1976-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-28 | 1980-05-29 | 1980-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-28 | 1984-05-29 | 1984-11-28 | $7700.00 | Window Closed / Lapsed |