Process and system for making cyclopentadiene and/or dicyclopentadiene

1. A process for making cyclopentadiene (CPD) and optionally dicyclopentadiene (DCPD), the process comprising:

(I) feeding a C5 feedstock comprising at least one acyclic C5 hydrocarbon into a first reactor;

(II) contacting the at least one acyclic C5 hydrocarbon with a catalyst under conversion conditions to obtain a first reactor hydrocarbon effluent comprising: C5 components including CPD and acyclic diolefins; light components including hydrogen and C1-C4 hydrocarbons; one-ring aromatics; and multiple-ring aromatics;

(III) contacting the first reactor hydrocarbon effluent with a wash oil in a washing vessel, thereby obtaining:

a heavy stream comprising at least a portion of the wash oil and at least a portion of the multiple-ring aromatics; and

a washed first reactor hydrocarbon effluent comprising at least a portion of the light components, at least a portion of the C5 components, and, optionally, a portion of the wash oil but depleted in multiple ring aromatics;

(IV) separating the washed first reactor effluent in a first separation sub-system to obtain:

a first C5-rich fraction comprising CPD and depleted of the light components;

a first light components-rich fraction comprising hydrogen and C1-C4 hydrocarbons; and

an optional first recovered wash oil stream;

(V) supplying the heavy stream and, optionally, at least a portion of the optional first recovered wash oil stream to a wash oil recovery sub-system;

(VI) obtaining, from the wash oil recovery sub-system:

a heavy oil fraction comprising the multiple-ring aromatics;

a second recovered wash oil stream; and

an optional recovered C5-rich stream comprising CPD; and

(VII) recycling at least a portion of the second recovered wash oil stream, and, optionally, at least a portion of the optional first recovered wash oil stream directly or indirectly to the washing vessel.

2. The process of claim 1 , wherein the wash oil recovery sub-system comprises at least one distillation column operated at least partly under wash oil recovery conditions such that DCPD, if present in the wash oil recovery sub-system, at least partly undergoes retro-Diels-Alder reaction to produce CPD.

3. The process of claim 1 , wherein:

the wash oil recovery sub-system comprises a first wash oil distillation column and a second wash oil distillation column;

in step (V), at least a portion of the heavy stream and the optional first recovered wash oil stream are supplied to the first wash oil distillation column;

and step (VI) comprises:

(VIa) obtaining from the first wash oil distillation column an upper stream comprising recovered C5 hydrocarbons as the recovered C5-rich stream, and a lower stream comprising the wash oil and the multiple-ring aromatics;

(VIb) supplying at least a portion of the lower stream into the second wash oil distillation column; and

(VIc) obtaining from the second wash oil distillation column:

the heavy oil fraction comprising at least a portion of the multiple-ring aromatics; and

the second recovered wash oil stream.

4. The process of claim 3 , wherein a flux oil is added to the first wash oil distillation column, the second wash oil distillation column, and/or the heavy oil fraction.

5. The process of claim 1 , wherein:

the wash oil recovery sub-system comprises a first wash oil divided-wall distillation column;

in step (V), at least a portion of the heavy stream and the optional first recovered wash oil stream are supplied to the first wash oil divided-wall distillation column;

and step (VI) comprises:

(VIa) obtaining from the first wash oil divided-wall distillation column:

an upper stream comprising recovered C5 hydrocarbons as the recovered C5-rich stream,

a middle stream comprising the recovered wash oil as the second recovered wash oil stream, and

a lower stream comprising the heavy oil fraction comprising at least a portion of the multiple-ring aromatics.

6. The process of claim 5 , wherein a flux oil is added the first wash oil divided-wall distillation column and/or the heavy oil fraction.

7. The process of claim 3 , wherein the wash oil recovery sub-system is operated at least partly under wash oil recovery conditions such that dicyclopentadiene (DCPD), if present in the wash oil recovery sub-system, at least partly undergoes retro-Diels-Alder reaction to produce CPD.

8. The process of claim 2 , wherein:

the heavy stream and/or the optional first recovered wash oil stream comprises DCPD;

the second recovered wash oil stream comprises CPD; and

the heavy oil fraction is essentially free of DCPD; such as less than 10 wt % DCPD.

9. The process of claim 1 , further comprising:

(VIII) feeding at least a portion of the second recovered wash oil stream and the first light components-rich fraction into a third light components separation device;

(IX) obtaining from the third separation device:

a second light components-rich fraction comprising hydrogen and C1-C4 hydrocarbons depleted in C5+ hydrocarbons, and

a third wash oil stream; and

(X) recycling at least a portion of the third wash oil stream to the washing vessel in step (III).

10. The process of claim 1 , further comprising feeding a fresh stream of wash oil into at least one of (i) the washing vessel and (ii) the third separation device.

11. The process of claim 1 , further comprising:

(XI) supplying at least a portion of the first C5-rich fraction and, optionally, the optional recovered C5-rich stream into a second reactor operating under a first set of dimerization conditions;

(XII) obtaining a second reactor effluent from the second reactor comprising CPD and DCPD; and

(XIII) separating at least a portion of the second reactor effluent to obtain:

a first DCPD-rich fraction comprising DCPD; and

a second C5-rich fraction.

12. The process of claim 11 , further comprising:

(XIV) feeding at least a portion of the second C5-rich fraction into a third reactor operating under a second set of dimerization conditions;

(XV) obtaining a third reactor effluent from the third reactor comprising CPD and DCPD; and

(XVI) separating at least a portion of the third reactor effluent to obtain:

a second DCPD-rich fraction; and

a third C5-rich stream.

13. The process of claim 11 , further comprising:

(XVII) feeding at least a portion of the third C5-rich fraction into a fourth reactor operating under a third set of dimerization conditions;

(XVIII) obtaining a fourth reactor effluent from the fourth reactor comprising CPD and DCPD; and

(XIX) separating at least a portion of the fourth reactor effluent in a fourth separation device to obtain:

a third DCPD-rich fraction; and

a fourth C5-rich stream.

14. The process of claim 11 , further comprising:

(XX) supplying at least a portion of at least one of the following into a fifth separation device: (i) the first C5-rich stream; (ii) the optional recovered C5-rich stream; (iii) the second C5-rich stream; (iv) the third C5-rich stream, if any; (v) the fourth C5-rich stream, if any; and

(XXI) obtaining, from the fourth separation device:

a fifth C5-rich stream; and

a one-ring aromatic(s)-rich stream.

15. The process of claim 14 , further comprising:

(X) recycling at least a portion of the one-ring aromatic(s)-rich stream directly or indirectly into the washing vessel in step (III) and/or the third separation device in step (VIII).

16. The process of claim 14 , wherein at least a portion of the one-ring aromatic(s)-rich stream is distilled to obtain a benzene-rich stream and a benzene-depleted stream and the benzene depleted stream is fed directly to at least one of (i) the washing vessel in step (III) and/or (ii) the third separation device in step (VIII).

17. The process of claim 1 , wherein the first separation sub-system comprises a compression train with inter-stage cooling and vapor/liquid separation.

18. The process of claim 1 , wherein the wash oil comprises at least one of: cylcohexane;

monoalkyl, dialkyl, and trialkyl cyclohexanes; benzene; monoalkyl, dialkyl, and trialkyl benzenes; monoalkyl, dialkyl, trialkyl, and tetraalkyl naphthalenes; other alkylated multiple-ring aromatics; and mixtures and combinations thereof.

19. The process of claim 18 , wherein:

the wash oil comprises at least 50 wt % of toluene, based on the total weight of the wash oil used in step (III).

20. The process of claim 18 , wherein:

the wash oil comprises at least 50 wt % of alklynaphthalenes, based on the total weight of the wash oil used in step (III); and

the optional first recovered wash oil stream is obtained in step (IV).

21. The process of claim 1 , wherein:

the first reactor hydrocarbon effluent comprises CPD at a concentration of C(CPD)1 wt % and acyclic diolefins at a total concentration of C(ADO)1 wt %, both based on the total weight of C5 hydrocarbons in the first reactor hydrocarbon effluent; and

C(CPD)1/C(ADO)1≧1.5.

22. The process of claim 1 , wherein:

step (IV) comprises:

(IVc) obtaining from the first light components-rich fraction to obtain at least one of:

(i) a hydrogen-rich stream comprising H 2 at a purity of at least 95 mol %;

(ii) a hydrogen/C1-C4 hydrocarbon stream comprising a mixture of H 2 and C1-C4 hydrocarbon; and

(iii) a C1-C4 hydrocarbon stream depleted of hydrogen.

23. The process of claim 11 , further comprising:

(XXIII) recycling, directly or indirectly, at least a portion of at least one of the first C5-rich fraction, the optional recovered C5-rich stream, the second C5-rich fraction, the third C5-rich fraction, the fourth C5-rich fraction, and/or the fifth C5-rich fraction, if produced, to the first reactor.

24. The process of claim 11 , further comprising:

(XXIV) obtaining at least one of: (i) a cyclopentane-rich fraction; (ii) a cyclopentene-rich fraction; (iii) a 1,3-pentadiene-rich fraction; and (iv) a 2-methyl-1,3-butadiene fraction, from at least one of the first C5-rich fraction, the optional recovered C5-rich stream, the second C5-rich fraction, the third C5-rich fraction, and the fourth C5-rich fraction, and the fifth C5-rich fraction, if produced.