Membrane-based gas separation processes to separate dehydrogenation reaction products

A process for treating a raw product stream from dehydrogenation of a light paraffin, said raw product stream comprising at least one paraffin component, one olefin component and hydrogen, comprising the sequential steps of:

• (a) compressing the raw product stream to create a compressed stream having a first hydrocarbon dewpoint;
• (b) partially condensing the compressed stream, including cooling to a temperature no lower than −30° C. and separating the compressed stream into a first hydrocarbon condensate stream and a first uncondensed gas stream;
• (c) heating the first uncondensed gas stream from step (b);
• (d) separating the first uncondensed gas stream from step (c) using a first membrane to remove a hydrogen-rich permeate gas stream and create a hydrocarbon-enriched residue gas stream having a first residue hydrocarbon dewpoint;
• and
• (e) partially condensing the residue gas stream, including cooling to a temperature no lower than −30° C. and separating the residue gas stream into a second hydrocarbon condensate and a second uncondensed gas stream;
• and
• (f) separating the second uncondensed gas stream from step (e) using a second membrane to remove a hydrocarbon-rich permeate gas stream;
• and
• (g) recompressing and recirculating the hydrocarbon-rich permeate gas stream to step (b).

A process for treating a raw product stream from dehydrogenation of a light paraffin, said raw product stream comprising at least one paraffin component, one olefin component and hydrogen, comprising the sequential steps of:

• (a) compressing the raw product stream to create a compressed stream having a first hydrocarbon dewpoint;
• (b) partially condensing the compressed stream, including cooling and separating the compressed stream into a first hydrocarbon condensate steam and a first uncondensed as stream;
• (c) heating the first uncondensed gas stream from step (b);
• (d) separating the first uncondensed gas stream from step (c) using a first membrane to remove a hydrogen-rich permeate gas stream and create a hydrocarbon-enriched residue gas stream having a first residue hydrocarbon dewpoint that is within 15° C. of the first hydrocarbon dewpoint;
• (e) partially condensing the residue gas stream, including cooling and separating the residue gas stream into a second hydrocarbon condensate and a second uncondensed gas stream
• (f) recirculating at least a first portion of the second uncondensed gas stream to step (c);
• (g) separating a second portion of the second uncondensed gas stream from step (e) using a second membrane to remove a hydrocarbon-rich permeate gas stream;
• and
• (h) recompressing and recirculating the hydrocarbon-rich permeate gas stream to step (b).

A process for treating a raw product stream from dehydrogenation of a light paraffin, said raw product stream comprising at least one paraffin component, one olefin component and hydrogen, comprising the sequential steps of:

• (a) compressing the raw product stream to create a compressed stream having a first hydrocarbon dewpoint;
• (b) partially condensing the compressed stream, including cooling to a temperature no lower than −30° C. and separating the compressed stream into a first hydrocarbon condensate stream and a first uncondensed gas stream;
• (c) heating the first uncondensed gas stream from step (b);
• (d) separating the first uncondensed gas stream from step (c) using a first membrane to remove a hydrogen-rich permeate gas stream and create a hydrocarbon-enriched residue gas stream having a first residue hydrocarbon dewpoint;
• (e) partially condensing the residue gas stream, including cooling to a temperature no lower than −30° C. and separating the residue gas stream into a second hydrocarbon condensate and a second uncondensed gas stream;
• (f) recirculating at least a first portion of the second uncondensed gas stream to step (c);
• (g) separating a second portion of the second uncondensed gas stream from step (e) using a second membrane to remove a hydrocarbon-rich permeate gas stream;
• and
• (h) recompressing and recirculating the hydrocarbon-rich permeate gas stream to step (b).

A process for treating a raw product stream from dehydrogenation of a light paraffin, said raw product stream comprising at least one paraffin component, one olefin component and hydrogen, comprising the sequential steps of:

• (a) compressing the raw product stream to create a compressed stream having a first hydrocarbon dewpoint;
• (b) partially condensing the compressed stream, including cooling and separating the compressed stream into a first hydrocarbon condensate stream and a first uncondensed gas stream;
• (c) heating the first uncondensed gas stream from step (b);
• (d) separating the first uncondensed gas stream from step (c) using a first membrane to remove a hydrogen-rich permeate gas stream and create a hydrocarbon-enriched residue gas stream having a first residue hydrocarbon dewpoint that is within 15° C. of the first hydrocarbon dewpoint;
• (e) partially condensing the residue gas stream, including cooling and separating the residue gas stream into a second hydrocarbon condensate and a second uncondensed gas stream;
• (f) recirculating at least a first portion of the second uncondensed gas stream to step (c);
• (g) separating the hydrogen-rich permeate gas stream from step (d) using a pressure swing adsorption unit to remove a second hydrogen-rich permeate gas stream and create a hydrocarbon-enriched tail gas stream;
• (h) recompressing and recirculating the hydrocarbon-enriched tail gas stream to step (c);
• (i) separating a second portion of the second uncondensed gas stream from step (e) using a second membrane to remove a hydrocarbon-rich permeate gas stream;
• and
• (j) recompressing and recirculating the hydrocarbon-rich permeate gas stream to step (b).

A process for treating a raw product stream from dehydrogenation of a light paraffin, said raw product stream comprising at least one paraffin component, one olefin component and hydrogen, comprising the sequential steps of:

• (a) compressing the raw product stream to create a compressed stream having a first hydrocarbon dewpoint;
• (b) partially condensing the compressed stream, including cooling to a temperature no lower than −30° C. and separating the compressed stream into a first hydrocarbon condensate stream and a first uncondensed gas stream;
• (c) heating the first uncondensed gas stream from step (b);
• (d) separating the first uncondensed gas stream from step (c) using a first membrane to remove a hydrogen-rich permeate gas stream and create a hydrocarbon-enriched residue gas stream having a first residue hydrocarbon dewpoint;
• and
• (e) partially condensing the residue gas stream, including cooling to a temperature no lower than −30° C. and separating the residue as stream into a second hydrocarbon condensate and a second uncondensed gas stream;
• (f) recirculating at least a first portion of the second uncondensed gas stream to step (c)
• (g) separating the hydrogen-rich permeate has stream from step (d) using a pressure swing adsorption unit to remove a second hydrogen-rich permeate gas stream and create a hydrocarbon-enriched tail gas stream;
• (h) recompressing and recirculating the hydrocarbon-enriched tail gas stream to step (e);
• (i) separating a second portion of the second uncondensed gas stream from step (e) using a second membrane to remove a hydrocarbon-rich permeate gas stream;
• and
• (j) recompressing and recirculating the hydrocarbon-rich permeate gas stream to step (b).