US 12,435,924 B2
Multiple reflux stream hydrocarbon recovery process
Galip Hakan Guvelioglu, The Woodlands, TX (US); and Fereidoun Yamin, Houston, TX (US)
Assigned to LUMMUS TECHNOLOGY LLC, Bloomfield, NJ (US)
Filed by LUMMUS TECHNOLOGY LLC, Bloomfield, NJ (US)
Filed on Jan. 22, 2021, as Appl. No. 17/155,320.
Claims priority of provisional application 62/965,339, filed on Jan. 24, 2020.
Prior Publication US 2021/0231367 A1, Jul. 29, 2021
Int. Cl. F25J 3/02 (2006.01)
CPC F25J 3/0238 (2013.01) [F25J 3/0209 (2013.01); F25J 3/0233 (2013.01); F25J 2200/70 (2013.01); F25J 2205/04 (2013.01); F25J 2210/06 (2013.01); F25J 2245/02 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A process for separating an inlet gas stream containing methane, C2 components, C3 components and optionally heavier hydrocarbons into a volatile gas fraction containing methane and a less volatile hydrocarbon fraction containing C2+ components, the process comprising the steps of:
for a first time period, operating the process in a high ethane recovery mode, comprising:
(a) splitting an inlet gas stream into a first feed stream and a second feed stream and cooling the first and the second feed streams to form a cooled first feed stream and a cooled second feed stream;
(b) separating the cooled first and second feed streams into a first vapor stream and a first liquid stream;
(c) expanding the first liquid stream thereby forming a first demethanizer tower feed stream;
(d) expanding the first vapor stream to a lower pressure thereby forming a second demethanizer tower feed stream;
(e) feeding the first and second demethanizer tower feed streams to a demethanizer tower, and
separating the feed streams into a demethanizer overheads stream and a demethanizer bottoms stream;
(f) warming and compressing the demethanizer overheads stream to form a residue gas stream; and
(g) recovering a first portion of the residue gas stream as a product stream and recycling a second portion of the residue gas stream to the demethanizer tower;
stopping recycling of the second portion of the residue gas; and
for a second time period, operating the process in a high throughput mode, comprising:
(aa) splitting the inlet gas stream into the first feed stream, the second feed stream, and a third feed stream, wherein the third feed stream has a composition substantially the same as the inlet gas stream;
(bb) cooling the first, the second, and the third feed streams to produce the cooled first feed stream, the cooled secon feed stream, and a cooled third feed stream;
(cc) separating the cooled first and second feed streams into the first vapor stream and the first liquid stream;
(dd) expanding the first liquid stream thereby forming the first demethanizer tower feed stream;
(ee) expanding the first vapor stream to a lower pressure thereby forming the second demethanizer tower feed stream;
(ff) feeding the first demethanizer tower feed stream, the second demethanizer tower feed stream, and the cooled third feed stream to the demethanizer tower, and separating the feed streams into the demethanizer overheads stream and the demethanizer bottoms stream;
(gg) warming and compressing the demethanizer overheads stream to form the residue gas stream recovered as the product.