Mitigation of deposits and secondary reactions in thermal conversion processes
View Patent ↗Described herein are systems and methods for reducing cumulative deposition and unwanted secondary thermal reactions in pyrolysis and other thermal conversion processes. In an embodiment, a system comprises a device, referred to as a reamer, for removing product deposits between thermal conversion and condensation operations of a pyrolysis process. The reamer may comprise, but is not limited to, a mechanical reciprocating rod or ram, a mechanical auger, a drill bit, a high-temperature wiper, brush, or punch to remove deposits and prevent secondary reactions. Alternatively or in addition, the reamer may use a high-velocity curtain or jet (i.e., a hydraulic or pneumatic stream) of vapor, product gas, recycle gas, other gas jet or non-condensing liquid to remove deposits. Preferably, the reamer removes deposits during the pyrolysis process allowing for continuous operation of the pyrolysis process.
1. A method for removing deposits in a pyrolysis assembly having a thermal reactor fluidly coupled with a pipeline to a condensing chamber, comprising:
(i) forming a vapor stream within the assembly by pyrolysis;
(ii) supplying the vapor stream continuously to the condensing chamber via the pipeline;
(iii) quenching at least a portion of the vapor stream in the condensing chamber forming a hot-cold zone in the pipeline and causing deposits to form;
(iv) sensing deposits in the pipeline with a pressure differential element; and
(v) removing at least a portion of the deposits by injecting a gaseous, vapor or liquid stream through a retractable nozzle, wherein the injection of the stream is controlled using a controller in communication with the pressure differential element.
2. The method of claim 1 , wherein the deposits collect within the pipeline.
3. The method of claim 1 , wherein the stream is injected into the pipeline at a velocity of 50 to 500 fps.
4. The method of claim 1 , wherein the stream is injected into the pipeline at a velocity of 100 to 200 fps.
5. The method of claim 1 , wherein the removing step further comprises extending the nozzle from a retracted position to an extended position.
6. The method of claim 1 , wherein the removing step further comprises using a reamer.
7. The method of claim 6 , wherein the reamer comprises a ram head.
8. The method of claim 7 , wherein the ram head comprises openings for allowing the vapor stream to pass.
9. The method of claim 6 , wherein the reamer comprises an auger.
10. The method of claim 9 , wherein the auger is rotated at a rate between 50 and 250 rpm.
11. The method of claim 9 , wherein the auger is rotated at a rate between 50 and 150 rpm.
12. The method of claim 10 , wherein the reamer comprises a brush head.
13. The method of claim 12 , wherein the brush head is rotated at a rate between 50 and 250 rpm.
14. The method of claim 12 , wherein the brush head is rotated at a rate between 50 and 150 rpm.
15. A method for removing deposits in a pyrolysis assembly having a thermal reactor fluidly coupled with a pipeline to a condensing chamber, comprising:
(i) forming a vapor stream within the assembly by pyrolysis;
(ii) supplying the vapor stream continuously to the condensing chamber via the pipeline;
(iii) quenching at least a portion of the vapor stream in the condensing chamber forming a hot-cold zone in the pipeline and causing deposits to form;
(iv) sensing deposits in the pipeline with a pressure differential element; and
(v) removing at least a portion of the deposits by using a reamer, wherein the reamer is controlled using a controller in communication with the pressure differential element.
16. The method of claim 15 , wherein the deposits collect within the pipeline.
17. The method of claim 15 , wherein the reamer comprises a ram head.
18. The method of claim 17 , wherein the ram head comprises openings for allowing the vapor stream to pass.
19. The method of claim 15 , wherein the reamer comprises an auger.
20. The method of claim 19 , wherein the auger is rotated at a rate between 50 and 250 rpm.
21. The method of claim 19 , wherein the auger is rotated at a rate between 50 and 150 rpm.
22. The method of claim 15 , wherein the reamer comprises a brush head.
23. The method of claim 22 , wherein the brush head is rotated at a rate between 50 and 250 rpm.
24. The method of claim 22 , wherein the brush head is rotated at a rate between 50 and 150 rpm.
25. The method of claim 15 , wherein the removing step further comprises injecting a gaseous, vapor or liquid stream into the pipeline to remove the deposits.
26. The method of claim 25 , wherein the stream is injected at a velocity of 50 to 500 fps.
27. The method of claim 25 , wherein the stream is injected at a velocity of 100 to 200 fps.
28. The method of claim 25 , wherein the stream is injected from a nozzle head within the pipeline.
29. The method of claim 28 , wherein the removing step further comprises extending the nozzle head from a retracted position to an extended position within the pipeline while injecting the gaseous, vapor or liquid stream from a nozzle head.