Claims
- 1. A method for increasing the heat transfer coefficient between a conduit and a gas stream flowing through said conduit comprising the steps of:
- (a) fluidizing a Geldart Type A powder in said gas stream; and
- (b) maintaining the fines content of said Geldart Type A powder at from about 10 to about 45 weight percent.
- 2. The process of claim 1 wherein said fines content is between about 18 and about 32 weight percent.
- 3. The process of claim 1 wherein said fines content is about 25 weight percent.
- 4. A method for transferring thermal energy to a fluidized-bed reaction zone comprising the steps of:
- (a) fluidizing a Geldart Type A powder having a fines content of from about 10 to about 45 weight percent in a first gas stream to form a fluidized heat transfer mixture;
- (b) fluidizing finely divided catalyst particles in a second gas stream having a sufficient flow rate to fluidize said finely divided catalyst particles in a sub-transport regime thus forming a fluidized-bed reaction zone;
- (c) transferring thermal energy from an energy source to said fluidized heat transfer mixture; and
- (d) indirectly transferring thermal energy from said fluidized heat transfer mixture to said fluidized-bed reaction zone.
- 5. The process of claim 4 wherein said fines content is between about 18 and about 32 weight percent.
- 6. The process of claim 4 wherein said fines content is about 25 weight percent.
- 7. The process of claim 4 further comprising retaining said Geldart Type A powder within at least one heat exchanger tube positioned within said fluidized-bed reaction zone.
- 8. The process of claim 4 further comprising heating said heat transfer mixture by direct contact with combustion zone flue gas.
- 9. A method for transferring thermal energy to a fluidized-bed reaction zone comprising the steps of:
- (a) fluidizing a Geldart Type A powder in a first gas stream to form a fluidized heat transfer mixture containing from about 10 to about 45 weight percent fines wherein said fines have a major cross-sectional dimension of less than about 40 microns;
- (b) fluidizing finely divided catalyst particles in a second gas stream having a sufficient flow rate to fluidize said finely divided catalyst particles in a sub-transport regime thus forming a fluidized-bed reaction zone;
- (c) heating said fluidized heat transfer mixture of step (a) by directly contacting said fluidized heat transfer mixture with combustion zone flue gas;
- (d) indirectly transferring thermal energy from said fluidized heat transfer mixture to said fluidized-bed reaction zone.
- 10. The method of claim 9 wherein said fines content is from about 18 to about 32 weight percent.
- 11. The method of claim 9 wherein said fines content is about 25 weight percent.
Parent Case Info
This is a divisional of copending application Ser. No. 284,627, filed on Dec. 15, 1988, now U.S. Pat. No. 4,914,255 granted Apr. 3, 1990.
US Referenced Citations (10)
Non-Patent Literature Citations (1)
Entry |
"Fluidized-bed Heat Exchanger Avoids Fouling Problems", Chemical Engineering, Feb. 15, 1988, p. 43. |
Divisions (1)
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Number |
Date |
Country |
Parent |
284627 |
Dec 1988 |
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