Systems and methods for LNG production with propane and ethane recovery

A LNG liquefaction plant comprising:

• a feed stream comprising methane, ethane, and propane;
• a propane recovery unit configured to produce LPG and an ethane-rich feed gas from the feed stream;
• an ethane recovery unit including:
• a compressor configured to compress the ethane-rich feed gas to form a compressed stream, wherein the compressed stream is configured to split into a first portion and a second portion, wherein the first portion of the compressed stream, the second portion of the compressed stream, and the ethane-rich feed gas are each ethane-rich, wherein the compressed stream and the second portion of compressed stream have the same composition;
• a demethanizer configured to produce an ethane liquid in an ethane bottom liquid stream and a residue gas in a methane overhead vapor stream, wherein a first portion of the residue gas is configured to flow to the demethanizer as a first reflux stream, wherein a second portion of the residue gas from the demethanizer is a methane-rich feed gas, wherein the first portion of the compressed stream is configured to flow to the demethanizer as a second reflux stream;
• a first heat exchanger configured to heat the methane overhead vapor stream, cool the first portion of the residue gas, and cool the first portion of the compressed stream;
• and
• an expander configured to expand the second portion of the compressed stream prior to entering the demethanizer;
• and
• a LNG liquefaction unit configured to receive the methane-rich feed gas, cool the methane-rich feed gas with a refrigerant cycle, and recover LNG from the methane-rich feed gas.