Claims
- 1. An apparatus for the manufacture of a hot mix asphalt (HMA) from a recycled asphalt pavement (RAP) comprising:
- (a) a counter flow rotary drum dryer for heating said RAP to a desired temperature, said RAP flowing through said drum dryer, said drum dryer having two opposite ends and comprising:
- (i) a RAP output,
- (ii) a RAP input,
- (iii) an input for entering combustion gases having desired temperatures and which flow thereafter in the drum dryer, and
- (iv) an exhaust output for combustion gases and vapors; said combustion gases and vapors having desired temperatures;
- (b) means for supplying said RAP to said RAP input,
- (c) a low NO.sub.x burner connected to said drum dryer for producing a flame; said burner positioned with respect to said drum dryer in such a way that the flame does not directly radiate energy to the RAP flowing through said drum dryer;
- (d) a means for supplying combustion air to an air inlet of the burner; and
- (e) a combustion gas air supply means for supplying a quantity of cooling air immedediately ahead of said burner and for producing complete combustion of fuel at a temperature which is below that which produces significant measurable NO.sub.x in the combustion gases;
- wherein said exhaust and RAP outputs are located on said opposite ends of said drum dryer.
- 2. The apparatus of claim 1, further comprising
- (a) a means to limit the temperatures of the combustion gases at the input for entering combustion gases to less than that which causes smoking and
- (b) a means to eliminate an infra-red-radiation heat produced by said flame.
- 3. The apparatus of claim 1 wherein the low NO.sub.x burner produces temperatures of the combustion gases at the input for entering combustion gases of about 1,100.degree. F.
- 4. The apparatus of claim 1, further comprising an extended duct which is at least 5 feet long for containing the combustion gases and for connecting the burner to the drum dryer.
- 5. The apparatus of claim 1, further comprising a duct having a bend, said duct being positioned between the burner and the drum dryer.
- 6. The apparatus of claim 1, further comprising a duct having baffles which prevent excessively hot combustion gases from reaching the drum, said duct being positioned between the burner and the drum dryer.
- 7. The apparatus of claim 1, wherein the low NO.sub.x burner produces temperatures of said combustion gases entering said drum which are 1,100.degree..+-.100.degree. F.
- 8. The apparatus of claim 1, wherein the low NO.sub.x burner produces a temperature of said RAP at any point in said drum which does not exceed 350.degree. F.
- 9. The apparatus of claim 1, wherein the low NO.sub.x burner produces gases which contact said RAP in said drum which do not exceed temperatures which produce smoking of said RAP.
- 10. The apparatus of claim 1, wherein said burner is supplied with gases, said gases being in larger amounts that which are required for a designed combustion by said burner.
- 11. The apparatus of claim 1, wherein said burner is supplied with ambient air in an amount which is sufficient to provide a short burn time of the flame so as to prevent creation of NO.sub.x during a combustion process.
- 12. The apparatus of claim 1, wherein said burner is supplied with ambient air in an amount which prevents a temperature of the flame from being sufficiently high to create NO.sub.x during the combustion process.
- 13. The apparatus of claim 1, wherein the low NO.sub.x burner produces a temperature of said combustion gases entering said drum which is at least 1,000.degree. F.
- 14. The apparatus of claim 1, wherein the low NO.sub.x burner produces a temperature of said combustion gases entering said drum which is in the range of about 900.degree. to about 1,300.degree. F.
- 15. The apparatus of claim 1, wherein the low NO.sub.x burner produces a temperature of the combustion gases at the input for entering combustion gases of said drum dryer which is about 1,200.degree. F.
- 16. The apparatus of claim 1, wherein the temperature of the combustion gases entering said drum dryer is dependent on a firing rate of said burner.
- 17. The apparatus of claim 1, wherein a temperature of the RAP at said RAP output is controlled by adjusting the rate of flow of RAP through the drum dryer.
- 18. The apparatus of claim 1, wherein a temperature (T1) of said RAP at said RAP output is controlled by adjusting a firing rate of said burner to the highest rate where there is no smoking of the RAP.
- 19. The apparatus of claim 1, wherein:
- (a) a temperature (T1a) of the gases in the drum is measured at a point downstream from said input for entering combustion gases and prior to the exit of said RAP from said drum; and
- (b) a burning rate of the burner is a function of the temperature (T1a).
- 20. The apparatus of claim 1, wherein said drum dryer further includes flights for lifting said RAP so as to allow said RAP to fall through the gases flowing in said drum dryer.
- 21. The apparatus of claim 1, wherein the low NO.sub.x burner is mounted on an axis which is the same as a longitudinal axis of the drum, and a burner tube connecting the burner to the drum incorporates baffles to shield said RAP from a radiant heat generated by the flame.
- 22. The apparatus of claim 21, wherein said baffles further prevent insertion of excessively hot gas regions in the drum.
- 23. The apparatus of claim 1, wherein the low NO.sub.x burner is mounted on an axis which is the same as a longitudinal axis of the drum, and a burner tube connecting the burner to the drum incorporates turbulence inducers to shield said RAP from a radiant heat generated by the flame.
- 24. The apparatus of claim 1, wherein said burner is supplied with gases in amounts which prevent the flame from reaching a temperature sufficient to create NO.sub.x during the combustion process.
- 25. A low NO.sub.x drum dryer for heating recycled asphalt pavement materials comprising in combination:
- (a) a counter flow rotary drum comprising:
- (i) a recycled asphalt pavement (RAP) input,
- (ii) a RAP output,
- (iii)a gas input, and
- (iv) an exhaust;
- (b) a low NO.sub.x burner means for producing a flame and generating a low amount of NO.sub.x located at a position with respect to said drum which prevents said flame from entering said drum;
- (c) a means for supplying combustion air to an air inlet of the burner means;
- (d) a combustion gas air supply means for supplying a quantity of cooling air immediately ahead of said low NO.sub.x burner means and for producing complete combustion of fuel at a temperature which is below that which produces significant measurable NO.sub.x in the combustion gases; and
- (e) a duct for supplying said combustion gases to said drum gas input from said burner means.
- 26. A low NO.sub.x dryer drum for heating recycled asphalt pavement materials comprising in combination;
- a counter flow rotating drum dryer having a recycled asphalt pavement (RAP) input and output and having a gas input and an exhaust;
- a low NO.sub.x burner means for producing emissions having low amounts of NO.sub.x ;
- a means for supplying combustion air to an air inlet of the burner means;
- a combustion gas air supply means for supplying a quantity of cooling air immedediately ahead of said burner means and for producing complete combustion of fuel at a temperature which is below that which produces significant measurable NO.sub.x in the combustion gases; and
- means for supplying said combustion gases to said dryer drum gas input.
- 27. An apparatus for the production of a hot mix asphalt (HMA) from a recycled asphalt pavement (RAP) comprising in combination:
- (a) a counter flow drum dryer having a RAP input and a RAP output;
- (b) a hopper storage means and a conveyor means for moving RAP from said hopper storage means to said drum dryer;
- (c) a burner means located remotely from said drum dryer for supplying combustion gases having a low NO.sub.x content to said drum dryer;
- (d) a means for supplying combustion air to an air inlet of the burner means:
- (e) a combustion gas air supply means for supplying a quantity of cooling air immediately ahead of said burner means and for producing complete combustion of fuel at a temperature which is below that which produces significant measurable NO.sub.x in the combustion gases;
- (f) a hot gas duct means connected to said burner means and to said drum for transmitting said combustion gases to said drum; and
- (g) means for rotating said drum for mixing said RAP, for moving RAP through said drum, and for allowing different surfaces of said RAP to come into contact with said combustion gases.
- 28. An apparatus for the manufacture of a hot mix asphalt (HMA) from a recycled asphalt pavement (RAP) comprising:
- (a) a counter flow rotary drum dryer for heating said RAP to a desired temperature, said RAP flowing through said drum dryer, said drum dryer having two opposite ends and comprising:
- (i) a RAP output,
- (ii) a RAP input,
- (iii) an input for entering combustion gases; said combustion gases having temperatures in the range of about 900.degree. F. to about 1,300.degree. F. and which flow thereafter in the drum dryer, and
- (iv) an exhaust output for combustion gases and vapors; said combustion gases and vapors having predetermined temperatures;
- (b) means for supplying said RAP to said RAP input,
- (c) a combustion burning means connected with said drum dryer; said burning means having a low NO.sub.x burner for producing a flame; said burner producing said input temperature range; said burner positioned with respect to said drum dryer in such a way that the flame does not directly radiate energy to the RAP flowing through said drum dryer;
- (d) a means for supplying combustion air to an air inlet of the burner;
- (e) a combustion gas air supply means for supplying a quantity of cooling air immedediately ahead of said burner and for producing complete combustion of fuel at a temperature which is below that which produces significant measurable NO.sub.x in the combustion gases; and
- (f) a means to eliminate an infra-red radiation heat produced by an open flame,
- wherein said exhaust and RAP outputs are located on said opposite ends of said drum dryer, and wherein a temperature of said RAP at any point in said drum dryer does not exceed 350.degree. F.
- 29. The apparatus of claim 28, further comprising an extended duct which is at least 5 feet long for containing the combustion gases and for connecting the burner to the drum dryer.
- 30. The apparatus of claim 28, further comprising a duct having a bend, said duct being positioned between the burner and the drum dryer.
- 31. The apparatus of claim 28, wherein said means to limit the temperatures of the combustion gases at the input to less than that which causes smoking comprise a duct having baffles which prevent excessively hot combustion gases from reaching the drum, said duct being positioned between the burner and the drum dryer.
- 32. The apparatus of claim 31, wherein the low NO.sub.x burner is mounted on an axis which is the same as a longitudinal axis of the drum, and the duct further comprises a turbulence inducer to shield said RAP from a radiant heat generated by the flame.
- 33. The apparatus of claim 32, wherein:
- (a) a temperature (T1a) of the gases in the drum is measured at a point downstream from said input for entering combustion gases and prior to the exit of said RAP from said drum; and
- (b) a burning rate of the burner is a function of the temperature (T1a).
RELATED APPLICATIONS
This application is a continuation of application Ser. No. 07/754,264, filed Aug. 29, 1991, now abandoned, which is a continuation of application Ser. No. 07/472,289, filed Jan. 30, 1990, now abandoned, which is a continuation in part of U.S. patent application Ser. No. 07/387,160 filed Jul. 31, 1989, now abandoned, entitled Drum Dryer For Reprocessing Recycled Asphalt Pavement, which is owned by the same corporation, Cyclean, Inc. a Delaware Corporation, and which was invented by Robert Nath a co-inventor in this case.
US Referenced Citations (31)
Foreign Referenced Citations (5)
Number |
Date |
Country |
3003547 |
Sep 1980 |
DEX |
2949479 |
Jun 1981 |
DEX |
27953 |
Feb 1984 |
JPX |
7906432 |
Mar 1981 |
NLX |
624088 |
Aug 1978 |
SUX |
Continuations (2)
|
Number |
Date |
Country |
Parent |
754264 |
Aug 1991 |
|
Parent |
472289 |
Jan 1990 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
387160 |
Jul 1989 |
|