Patent US3765377A successfully refreshed from Google Patents.
US3765377A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air pollution control system for chemical recovery unit
Assignee: Combustion Engineering Inc
•
Filing: 1972-06-23
•
Granted: 1973-10-16
•
Expires: 1992-06-23
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. Low pressure superheated steam is used as the heating medium in the direct contact evaporator, and also in a first air preheater supplying primary combustion air to the furnace. Moisture evaporated from the black liquor in the evaporator, and also steam leaving the first air preheater, is used to preheat secondary combustion air for the furnace.
Inventors
- 👤 J Freiday
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:29
CPC Classifications
F; F23; F23G; F23G7/00; F23G7/04; Y; Y10; Y10S; Y10S122/00; Y10S122/02
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
150 words
A chemical recovery unit comprising in combination a furnace including first superheat means associated with the furnace, second superheat means associated with the furnace, evaporation means for evaporating moisture from black liquor prior to its introduction into the furnace, a first air duct for conveying combustion air to the furnace to be used as secondary combustion air, a second air duct for conveying combustion air to the furnace to be used as primary air, first conveying means extending from the second superheat means to the evaporation means, second conveying means extending from the evaporation means to the second superheat means, first air preheater means located in the first air duct, second air preheater means located in the second air duct, third conveying means extending from the second conveying means to the first air preheater means, fourth conveying means extending from the first conveying means to the second air preheater means.
Claim 2
Dependent Claim
150 words
A chemical recovery unit comprising in combination a furnace including first superheat means associated with the furnace, second superheat means associated with the furnace, evaporation means for evaporating moisture from black liquor prior to its introduction into the furnace, a first air duct for conveying combustion air to the furnace to be used as secondary combustion air, a second air duct for conveying combustion air to the furnace to be used as primary air, first conveying means extending from the second superheat means to the evaporation means, second conveying means extending from the evaporation means to the second superheat means, first air preheater means located in the first air duct, second air preheater means located in the second air duct, third conveying means extending from the second conveying means to the first air preheater means, fourth conveying means extending from the first conveying means to the second air preheater means.
Claim 3
Dependent Claim
25 words
The chemical recovery unit set forth in claim 1, including fifth conveying means extending from the second air preheater means to the third conveying 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) | 1976-10-15 | 1977-04-16 | 1977-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-15 | 1981-04-16 | 1981-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-15 | 1985-04-16 | 1985-10-16 | $7700.00 | Window Closed / Lapsed |