Natural gas liquefaction employing independent refrigerant path

A method of natural gas liquefaction, the method comprising:

• compressing a gaseous refrigerant stream in a refrigerant loop received from a first channel of a multi-pass heat exchanger;
• cooling the gaseous refrigerant stream in a second channel of the multi-pass heat exchanger to form an at least partially gaseous refrigerant stream;
• expanding a gaseous phase of the at least partially gaseous refrigerant stream;
• directing the gaseous phase of the at least partially gaseous refrigerant stream into the first channel of the multi-pass heat exchanger to extract heat from a gaseous natural gas process stream in a path separate from the refrigerant loop passing through a third channel of the multi-pass heat exchanger and form the gaseous refrigerant stream;
• and
• expanding the gaseous natural gas process stream to form a liquid natural gas processing stream.

A natural gas liquefaction plant, comprising:

• a natural gas processing path comprising:
• a first channel of a multi-pass heat exchanger configured to cool a gaseous natural gas process stream;
• a pressure-reducing device configured to expand the cooled gaseous natural gas process stream to form a multi-phase natural gas process stream;
• and
• a separation vessel configured to separate phases of the multi-phase natural gas process stream to form a liquid natural gas process stream;
• and
• a refrigeration loop isolated from the natural gas processing path, and comprising:
• at least one compressor configured to compress a gaseous refrigerant stream;
• at least one heat exchanger positioned downstream of the at least one compressor and configured to cool the gaseous refrigerant stream;
• a second channel of the multi-pass heat exchanger positioned downstream of the at least one heat exchanger and configured to cool the gaseous refrigerant stream to form an at least partially gaseous refrigerant stream;
• a turbo expander positioned downstream of the second channel of the multi-pass heat exchanger and configured to expand and cool a gaseous phase of the at least partially gaseous refrigerant stream;
• and
• a third channel of the multi-pass heat exchanger positioned downstream of the turbo expander and configured to warm the at least partially gaseous refrigerant stream to form the gaseous refrigerant stream.