US4213407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flash drying sludge derived fuel process
Assignee: Occidental Chemical Corp
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Filing: 1978-12-27
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Granted: 1980-07-22
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Expires: 1998-12-27
Abstract
Abstract A process for disposing of sewage sludge resulting from municipal type sewage plants, including the production of dry solid fuel which is used in the flash drying and in the deodorizing system. Supplemental fuels are not required. The system is capable of producing a sludge derived fuel (SDF).
Inventors
- 👤 Kenneth N. Headley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:37
CPC Classifications
C; C02; C02F; C02F11/00; C02F11/12; C02F11/13; F; F23; F23G; F23G5/00; F23G5/44; F23G5/46; F23G7/00; F23G7/001; F23G7/06; F23G7/061; F23J; F23J15/00; F23J15/06; F26; F26B; F26B1/00; F26B23/00; F26B23/02; F26B23/022; F26B23/028; F26B3/00; F26B3/02; F26B3/06; F26B3/08; F26B3/092; F26B3/0923; Y; Y02; Y02E; Y02E20/00; Y02E20/30; Y02W; Y02W10/00; Y02W10/30
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
121 words
A process for disposing of sewage sludge comprising the steps of: (a) introducing the sludge into a direct fired roller mill for drying, pulverizing, and classification, thereby producing a dried product and a water vapor containing exhaust gas, (b) conveying said product from the mill by the vapor exhaust gas stream of the mill to a product collector wherein a portion of said product is removed and supplied to a furnace as fuel, (c) superheating said vapor exhaust gas stream leaving the product collector prior to injection into said furnace by heat exchange in a vapor preheater with the furnace exhaust gases, and (d) conducting a portion of said furnace exhaust gases to said mill for heating and drying said sludge.
Claim 2
Dependent Claim
121 words
A process for disposing of sewage sludge comprising the steps of: (a) introducing the sludge into a direct fired roller mill for drying, pulverizing, and classification, thereby producing a dried product and a water vapor containing exhaust gas, (b) conveying said product from the mill by the vapor exhaust gas stream of the mill to a product collector wherein a portion of said product is removed and supplied to a furnace as fuel, (c) superheating said vapor exhaust gas stream leaving the product collector prior to injection into said furnace by heat exchange in a vapor preheater with the furnace exhaust gases, and (d) conducting a portion of said furnace exhaust gases to said mill for heating and drying said sludge.
Claim 3
Dependent Claim
26 words
The process of claim 1 wherein the furnace exhaust gas that passed through the vapor preheater is vented to the atmosphere after removal of entrained particles.
Claim 4
Dependent Claim
81 words
The process of claim 1, wherein the said furnace is adapted for deodorizing the vapor exhaust stream exiting from the direct fired mill comprising tangential injection of the vapor stream into the furnace and mixing the vapors with the combustion gases formed in the furnace, thereby permitting the cooling of the gases in the periphery of the furnace and the heating of the vapors by contact with the combustion gases in the interior of the furnace to the minimum deodorizing temperature.
Claim 5
Dependent Claim
27 words
The process of claim 1, wherein said furnace is automatically controlled to operate at or above the deodorizing temperature independent of the rate of the vapor stream.
Claim 6
Dependent Claim
34 words
The process of claim 4, wherein the amount of combustion air is automatically controlled by operation of the combustion air fan which in turn is determined by oxygen analysis of the furnace exhaust gases.
Claim 7
Dependent Claim
28 words
The process of claim 1, wherein the vapor stream contains less than 5% oxygen and greater than 40% superheated water vapor thereby rendering it a non-oxidizing conveying gas.
Claim 8
Dependent Claim
25 words
The process of claim 1, wherein the vapor preheater provides cooling of furnace exhaust gases to about 75° F. (40° C.) of the estimated dewpoint.
Claim 9
Dependent Claim
35 words
The process of claim 7, wherein the cooling of the exhaust gases is controlled by automatic operation of the recycle vapor fan which in turn is determined by the temperature of the system exhaust gases.
Claim 10
Dependent Claim
24 words
The process of claim 1, wherein recovery of sludge derived fuel is obtained when the feed moisture content is less than 84% by weight.
Claim 11
Dependent Claim
15 words
The product produced by the process of claim 1, comprising a dry sludge derived fuel.
References Cited (Backward Citations)
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-07-22 | 1984-01-21 | 1984-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-22 | 1988-01-21 | 1988-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-22 | 1992-01-21 | 1992-07-22 | $7700.00 | Window Closed / Lapsed |