Controlled combustion for regenerative reactors

Abstract

The overall efficiency of a regenerative bed reverse flow reactor system is increased where the location of the exothermic reaction used for regeneration is suitably controlled. The present invention provides a method and apparatus for controlling the combustion to improve the thermal efficiency of bed regeneration in a cyclic reaction/regeneration processes. The process for thermal regeneration of a regenerative reactor bed entails (a) supplying the first reactant through a first channel means in a first regenerative bed and supplying at least a second reactant through a second channel means in the first regenerative bed,(b) combining said first and second reactants by a gas mixing means situated at an exit of the first regenerative bed and reacting the combined gas to produce a heated reaction product,(c) passing the heated reaction product through a second regenerative bed thereby transferring heat from the reaction product to the second regenerative bed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of thermal regeneration in a reverse flow reactor.

FIG. 2 is a diagrammatic illustration of a regenerative bed reactor with means for controlling the location of the exothermic reaction.

FIG. 3 illustrates an axial view of a gas distributor.

FIG. 4 is an axial view of gas mixer. FIG. 4a is a cutout cross-sectional view of a portion of FIG. 4.

FIG. 5 a is a diagrammatic illustration of a conventional Regenerative Thermal Oxidation Reactor; 5b is an illustration of a RTO Reactor with controlled combustion.

FIG. 6 a is a graph of temperature versus distance from the top of the regenerative bed for an embodiment of the present invention; FIG. 6b is a graph of temperature versus distance from the top of the regenerative bed for a fuel insertion device.

Claims

1. A process for controlling the location of an exothermic reaction between two or more reactants in a cyclic reverse-flow reactor system comprising: (a) supplying the first reactant through a first channel means in a first regenerative bed and supplying at least a second reactant through a second channel means in the first regenerative bed,(b) combining said first and second reactants by a gas mixing means situated at an exit of the first regenerative bed and reacting the combined gas to produce a heated reaction product,(c) passing the heated reaction product through a second regenerative bed thereby transferring heat from the reaction product to the second regenerative bed.

2. The process of claim 1 wherein said cyclic reverse flow reactor system comprises a reaction zone and a recuperation zone, and a gas mixer means situated therebetween.

3. The process of claim 1 wherein said first and second channel means axially traverse the first regenerative bed and pass the first and second gas to the gas mixer means.

4. The process of claim 3 wherein the gas mixer means comprises segments, axially aligned with the first and second channel means.

5. The process of claim 4 wherein the gas mixer segment have axial cross sectioned areas that are about equal in area.

6. The process of claim 5 wherein the gas mixer segments include gas swirl means that function to mix gases flowing therethrough.

7. The process of claim 6 wherein gas from the first and second channel means flow into the gas mixer segments, combining therein, combusting and passing through the second regenerative beds.

8. The process of claim 7 wherein the gas from first and second channel means are each divided about equally among the gas miser segments.

9. The process of claims 2 or 7 wherein said combusting occurs proximate to an interface between the gas mixer means and the second regenerative bed.

10. The process of claims 2 or 4 wherein the gas mixer means is constructed from material able to withstand temperatures in excess of about 600° C.

11. The process of claim 10 wherein the gas mixer means is constructed from material able to withstand temperatures in excess of about 1000° C.

12. The process of claim 11 wherein the gas mixer is constructed from material able to withstand temperatures in excess of about 1300° C.

13. The process of claim 9 wherein the gas mixer comprises a ceramic.

14. The process of claim 2 wherein the reaction zone has a volume A, and recuperator zone has a volume B, and the gas mixer means has a volume C, whereby volume C is less than about twenty percent of volume A plus volume B plus volume C.

15. The process of claim 14 wherein volume C is less than about ten percent of volume A plus volume B plus volume C.

16. The process of claim 4 wherein the gas mixer segments have an axial cross sectional area whose linear dimension is D, and an axial length L, the ratio of L to D ranges from about 0.1 to about 5.0.

17. The process of claim 4 wherein the gas mixer segments have an axial cross sectional area whose linear dimension is D, and an axial length L, the ratio of L to D ranges from about 0.3 to about 2.5.

18. The process of claim 1 wherein said first and second channel means function to maintain said first and second reactants separated such that at least fifty percent of such gases have not reacted in the first regenerative bed while transiting the first regenerative bed.

19. The process of claim 17 wherein at least seventy-five percent of the reactant gases have not reacted in the first regenerative bed.

20. The process of claim 1 wherein the cyclic reverse-flow reactor system is an asymmetric reaction chemistry system coupling the exothermic reaction with an endothermic reaction.

21. The process of claim 19 wherein the endothermic reaction of the cyclic reverse-flow reactor system comprises steam reforming, carbon dioxide reforming, pyrolysis, catalytic cracking, dehydrogenation, dehydration, or combinations thereof.

22. The process of claim 20 wherein the pyrolysis reaction comprises steam cracking reactions of ethane, naptha, gas oil or combinations thereof.

23. The process of claim 20 wherein the dehydrogenation reaction comprises alkane dehydrogenation, alkyl-aromatic dehydrogenation, or combinations thereof.

24. The process of claim 20 wherein the dehydration reaction comprises methanol dehydration, ethanol dehydration, or combinations thereof.

25. The process of claim 20 wherein the pyrolysis reaction includes hydropyrolysis reactions comprising methane hydropyrolysis to produce acetylene.

26. The process of claim 20 wherein the pyrolysis reaction comprises H2S pyrolysis.

27. The process of claim 1 wherein the first reactant is a fuel comprising CO, H2, hydrocarbon(s), oxygenates, petrochemical, or a mixture thereof.

28. The process of claim 1 wherein the second reactant is an oxygen containing gas.

29. The process of claim 26 wherein the oxygen containing gas is air.

30. The process of claims 26 or 27 wherein the first reactant, or the second reactant, or both, further comprise non-combustible gas or gases.

31. The process of claim 1 wherein the cyclic reverse flow reactor system is a symmetric reaction system.

32. The process of claim 30 wherein the exothermic reaction comprises full oxidation or partial oxidation.