Conversion of propane to propylene

1. A process comprising:

providing a stream comprising primarily propane;

reacting at least some of the propane with bromine to form a dibromopropane, bromopropane, HBr, and propane mixture;

separating the dibromopropane, brompropane, HBr, and propane from the dibromopropane, bromopropane, HBr, and propane mixture;

reacting the dibromopropane with a source of hydrogen to form a second bromopropane stream comprising bromopropane;

dehydrobrominating the bromopropane in the second bromopropane stream to form a propylene and HBr mixture;

separating the propylene and HBr mixture to form propylene and recycle HBr;

oxidizing the recycle HBr to form a bromine and water mixture; and

separating the bromine and water mixture to form recycle bromine.

2. The process of claim 1 , wherein the step of reacting at least some of the propane with bromine is performed at a temperature of between 200° C. and 375° C.

3. The process of claim 1 , wherein the step of reacting at least some of the propane with bromine is performed with a stoichiometric excess of propane.

4. The process of claim 1 , wherein the step of reacting the dibromopropane with the source of hydrogen is performed using a catalyst.

5. The process of claim 4 , wherein the catalyst is Pd, Pt, Ni, Ru or Cu.

6. The process of claim 4 , wherein the source of hydrogen is an alkane.

7. The process of claim 4 , wherein the source of hydrogen is hydrogen.

8. The process of claim 7 , wherein the hydrogen contains HBr.

9. The process of claim 1 , wherein the dehydrobrominating step is performed using a catalyst, wherein the catalyst is selected from the group consisting of a silica-based catalyst, titanium dioxide, zirconium dioxide and their mixtures thereof.

10. The process of claim 1 , wherein separating the propylene and HBr mixture is accomplished by absorbing the HBr in aqueous HBr to form a concentrated HBr solution.

11. The process of claim 10 , further comprising after the step of absorbing the HBr in aqueous HBr to form a concentrated HBr solution;

stripping the HBr from the concentrated aqueous HBr.

12. The process of claim 1 , wherein the step of oxidizing HBr is performed at a temperature of between 200° C. and 700° C.

13. The process of claim 1 , wherein the step of separating the propylene and HBr mixture is accomplished by distillation.

14. A process comprising:

providing a process feed stream comprising primarily propane;

reacting at least some of the propane in the process feed stream with bromine in a bromine recycle stream to form a dibromopropane, bromopropane, HBr, and propane stream comprising a mixture of dibromopropane, bromopropane, HBr, and propane;

separating the dibromopropane, bromopropane, HBr, and propane stream to form a dibromopropane stream, a bromopropane stream, an HBr stream, and a propane recycle stream;

combining the propane recycle stream with a fresh propane stream to form the process feed stream;

reacting the dibromopropane stream with a source of hydrogen;

combining the bromopropane stream with a portion of a bromopropane recycle stream to form a bromopropane feed stream;

dehydrobrominating the bromopropane in the bromopropane feed stream to form a propylene, HBr, and bromopropane mixture;

separating the propylene, HBr, and bromopropane mixture to form a propylene product stream, a recycle HBr stream and the bromopropane recycle stream;

combining the HBr stream and the recycle HBr stream to form an oxidizer feed stream;

oxidizing the oxidizer feed stream to form a bromine and water mixture stream; and

separating the bromine and water mixture to form the recycle bromine stream.

15. The process of claim 14 , consisting of hydrobrominating at least a portion of the bromopropane recycle stream to form a mixture comprised of dibromopropane.

16. The process of claim 15 , further comprising hydrogenating the dibromopropane mixture to form bromopropane.

17. A process comprising:

providing a process feed stream comprising propane;

providing a bromine stream comprising bromine;

reacting at least some of the propane in the process feed stream with bromine in the bromine stream to form a dibromopropane, bromopropane, HBr, and propane stream;

separating the dibromopropane, bromopropane, HBr, and propane stream to form a lights stream comprising propane and HBr, a bromopropane stream, and a dibromopropane stream;

reacting the dibromopropane stream with a source of hydrogen;

combining the lights stream with aqueous HBr;

absorbing the HBr from the lights stream to form a recycle propane stream and a concentrated HBr stream;

combining the recycle propane stream with a fresh propane stream to form the process feed stream;

stripping dry HBr from the concentrated HBr stream to form an HBr gas stream;

combining the bromopropane stream with a recycle bromopropane stream to form a dehydrobromination feed stream;

dehydrobrominating the dehydrobromination feed stream to form a dehydrobromination reactor discharge stream comprising HBr, propylene, and bromopropane;

absorbing the HBr in the dehydrobromination reactor discharge stream using aqueous HBr to form a propylene stream comprising primarily propylene and a concentrated HBr stripper feed stream;

separating the bromopropane from the propylene;

stripping the HBr from the concentrated HBr stripper feed stream to form an HBr oxidation stream;

combining the HBr oxidation stream and the HBr gas stream to form an oxidation feed stream;

oxidizing the oxidation feed stream to form a bromine and water mixture stream; and

separating bromine from water in the bromine and water mixture stream to form the bromine stream.