Process to produce alkenes from shale gas
Systems and processes for producing one or more alkenes from shale gas. The process includes at least two dehydrogenation reactors whereby propane, or a mixture of propane and butane, can be dehydrogenated in a first reactor and ethane can be dehydrogenated in a second reactor. The lighter components which serve as chemical inert and thermal mass are separated from the dehydrogenated product after each reactor.
1. A process for dehydrogenation of alkane or alkane mixtures, comprising:
providing a hydrocarbon feed stream comprising methane, ethane, and propane;
dehydrogenating the hydrocarbon feed stream in a first reactor at conditions sufficient to convert propane to propylene to provide a first dehydrogenation reactor effluent comprising propylene, methane, ethane, and unreacted propane;
separating a stream comprising methane and ethane from the first dehydrogenation reactor effluent to provide a separated stream comprising methane and ethane; and
dehydrogenating the separated stream comprising methane and ethane from the first dehydrogenation reactor effluent in a second reactor at conditions sufficient to convert ethane to ethylene to provide a second dehydrogenation reactor effluent comprising ethylene.
2. The process of claim 1 , wherein the concentration of methane in the hydrocarbon feed stream is at least 30 mol % and the concentration of propane and ethane combined is at least 5 mol %, and propane concentration is at least 2 mol %.
3. The process of claim 1 , wherein the hydrocarbon feed stream is a shale gas stream or a natural gas stream.
4. The process of claim 1 , wherein propylene is recovered as product from the first dehydrogenation reactor effluent.
5. The process of claim 1 , wherein the unreacted propane in the first dehydrogenation reactor effluent is separated and recycled to the first reactor.
6. The process of claim 5 , wherein a portion of the separated propane is recovered as a product.
7. The process of claim 1 , wherein ethylene is recovered as product from the second dehydrogenation reactor effluent.
8. The process of claim 1 , wherein ethane is separated from the second dehydrogenation reactor effluent and recycled to the second dehydrogenation reactor.
9. The process of claim 1 , wherein ethane is separated from the second dehydrogenation reactor effluent and recovered as a product.
10. The process of claim 1 , wherein hydrogen is separated from the first dehydrogenation reactor effluent or the second dehydrogenation reactor effluent or both effluents, and a portion of the separated hydrogen is fed to the first reactor.
11. The process of claim 10 , wherein a hydrogen to propane ratio is 0.1:1 to 1:1.
12. The process of claim 1 , wherein at least one of the dehydrogenation reactors is an electrically heated reactor.
13. The process of claim 1 , wherein at least one of the ethylene and propylene products is further oligomerized into one or more liquid hydrocarbons.
14. A process for dehydrogenation of alkane or alkane mixtures, comprising:
providing a hydrocarbon feed stream comprising methane, ethane, propane, and butane;
dehydrogenating the hydrocarbon feed stream in a first reactor at conditions sufficient to convert propane to propylene and to convert butane to butylene, providing a first dehydrogenation reactor effluent comprising propylene, butylene, methane, ethane, unreacted propane, and unreacted butane;
separating a stream comprising methane and ethane from the first dehydrogenation reactor effluent to provide a separated stream comprising methane and ethane; and
dehydrogenating the separated stream comprising methane and ethane from the first dehydrogenation reactor effluent in a second reactor at conditions sufficient to convert ethane to ethylene to provide a second dehydrogenation reactor effluent comprising ethylene.
15. The process of claim 14 , wherein the concentration of methane in the hydrocarbon feed stream is at least 30 mol % and the concentration of ethane, propane and butane combine is at least 5 mol %, and the combined propane and butane concentration is at least 2 mol %.
16. The process of claim 14 , wherein the hydrocarbon feed stream is a shale gas stream or a natural gas stream.
17. The process of claim 14 , wherein the propylene and butylene are recovered as product from the first dehydrogenation reactor effluent.
18. The process of claim 14 , wherein the unreacted propane and butane from the first dehydrogenation reactor effluent are separated and recycled to the first dehydrogenation reactor.
19. The process of claim 14 , wherein the unreacted ethane from the second dehydrogenation reactor effluent is separated and recycled to the second dehydrogenation reactor.
20. The process of claim 14 , wherein a portion of the propane or butane is recovered as a product.
21. The process of claim 14 , wherein a portion of the ethane is recovered as a product.
22. The process of claim 14 , wherein hydrogen is separated from the first dehydrogenation reactor effluent or the second dehydrogenation reactor effluent or both effluents, and a portion of the separated hydrogen is fed to the first reactor.
23. The process of claim 14 , wherein a hydrogen to propane ratio is 0.1:1 to 1:1.
24. The process of claim 14 , wherein at least one of the dehydrogenation reactors is an electrically heated reactor.
25. The process of claim 14 , wherein at least one of the ethylene, propylene and butylene products is further oligomerized into one or more liquid hydrocarbons.