Natural gas liquefaction by a high pressure expansion process using multiple turboexpander compressors

A method and system for liquefying a feed gas stream including natural gas. The feed gas stream is provided at a pressure less than 82,7 bara. A refrigerant stream (408) having a pressure of at least 103,4 bara is cooled (410) and then expanded in a first expander (414) to an intermediate pressure. The first expander is mechanically coupled to a first coupled compressor (438) to together form a first turboexpander-compressor. The refrigerant stream is expanded in a second expander (418), which is mechanically coupled to a second coupled compressor (429) to together form a second turboexpander-compressor. The refrigerant stream cools the feed gas stream (406) in one or more heat exchangers (422). Using the second coupled compressor (429) and a first driven compressor (431), the refrigerant stream is compressed to a discharge pressure within 20,7 bara of the intermediate pressure. The refrigerant stream is compressed using the first coupled compressor (438) and is further compressed (442) to provide the refrigerant stream.