Processes and systems for converting hydrocarbons to cyclopentadiene

1. A process for converting acyclic C 5 hydrocarbons to cyclopentadiene in a reactor system, wherein the process comprises:

providing to at least one adiabatic reaction zone a feedstock comprising acyclic C 5 hydrocarbons at a temperature, T 1 , wherein the at least one adiabatic reaction zone comprises a first particulate material comprising a catalyst material;

contacting the feedstock and the first particulate material in the at least one adiabatic reaction zone under reaction conditions to convert at least a portion of the acyclic C 5 hydrocarbons to a first effluent comprising cyclopentadiene intermediates, unconverted acyclic C 5 hydrocarbons and, optionally, cyclopentadiene;

heating the first effluent to a temperature, T 2 ;

providing the first effluent to at least one diabatic reaction zone; and

contacting the first effluent and a second particulate material in the at least one diabatic reaction zone under reaction conditions to convert at least a portion of the cyclopentadiene intermediates and the unconverted acyclic C 5 hydrocarbons to a second effluent comprising cyclopentadiene.

2. The process of claim 1 , wherein a heat duty for the at least one diabatic reaction zone is reduced by at least 3.0% per unit of cyclopentadiene produced when compared to a process where the adiabatic reaction zone is not present.

3. The process of claim 1 , wherein an inverse temperature profile or an isothermal temperature profile is maintained in the at least one diabatic reaction zone.

4. The process of claim 1 , wherein the at least one adiabatic reaction zone is a fixed bed reactor or a fluidized bed reactor.

5. The process of claim 1 , wherein T 1 and/or T 2 is less than or equal to about 500° C.

6. The process of claim 1 , wherein the second effluent exiting the at least one diabatic reaction zone has a temperature of at least about 550° C.

7. The process of claim 1 further comprising feeding a light hydrocarbon co-feedstock comprising C 1 , C 2 , C 3 , and/or C 4 hydrocarbons to the at least one adiabatic reaction zone.

8. The process of claim 1 further comprising feeding H 2 to the at least one adiabatic reaction zone and/or the at least one diabatic reaction zone.

9. The process of claim 1 , wherein the at least one diabatic reaction zone comprises at least one heating device.

10. The process of claim 1 , wherein the reaction conditions in the at least one diabatic reaction zone comprise a temperature of about 400° C. to about 800° C. and a pressure of about 3 psia to about 150 psia.

11. The process of claim 1 , wherein the reaction conditions in the at least one adiabatic reaction zone comprise a temperature of about 450° C. to about 900° C. and a pressure of about 3 psia to about 150 psia.

12. The process of claim 1 , wherein at least about 30 wt % of the acyclic C 5 hydrocarbons are converted to cyclopentadiene.

13. The process of claim 1 , wherein the at least one diabatic reaction zone is a circulating fluidized bed reactor, a circulating settling bed reactor, a fixed bed reactor, a cyclic fixed bed reactor, a fluidized bed reactor, a fired tubes reactor, or a convectively heated tubes reactor.

14. The process of claim 13 , wherein the second particulate material is a catalyst composition comprising platinum on ZSM-5, platinum on zeolite L, and/or platinum, and wherein the catalyst composition is formed into a structured catalyst shape on silicate modified silica.

15. The process of claim 13 , wherein the at least diabatic reaction zone comprises a reactor including parallel reactor tubes, and wherein the reactor tubes, during contacting the first effluent and a second particulate material, have a pressure drop measured from reactor inlet to reactor outlet of less than 20 psi.

16. The process of claim 1 , wherein the first effluent flows co-current or counter-current to a direction of a flow of the second particulate material in the at least one diabatic reaction zone.

17. The process of claim 1 , further comprising cyclically halting the feedstock to the at least one adiabatic reaction zone and/or the first effluent to the at least one diabatic reaction zone; and providing a rejuvenation gas to the at least one adiabatic reaction zone and/or the at least one diabatic reaction zone.

18. The process of claim 17 , wherein the feedstock and/or the first effluent flows co-current or counter-current to a direction of a flow of the rejuvenation gas.

19. The process of claim 17 , wherein the rejuvenation gas comprises hydrogen and the rejuvenation gas contacts the first particulate material and/or the second particulate material to remove at least a portion of incrementally deposited coke material on the catalyst material thereby forming a rejuvenated catalyst material and a volatile hydrocarbon.

20. The process of claim 19 , wherein at least about 10.0 wt % of the incrementally deposited coke material is removed from the catalyst material.

21. The process of claim 1 , further comprising cyclically halting the feedstock to the at least one adiabatic reaction zone and/or the first effluent to the at least one diabatic reaction zone; supplying a regeneration gas to the at least one adiabatic reaction zone and/or to the at least one diabatic reaction zone; and contacting the first particulate material and/or the second particulate material with the regeneration gas under regenerating conditions to oxidatively remove at least a portion of coke material deposited on the catalyst material thereby forming a regenerated catalyst material.

22. The process of claim 21 , wherein the regeneration gas contacts the first particulate material and/or the second particulate material at an interval of about every 1 day to about 180 days.

23. The process of claim 1 , wherein the first particulate material and the second particulate material are the same.

24. The process of claim 1 , wherein the first particulate material and the second particulate material are different.