Method to produce liquefied natural gas (LNG) at midstream natural gas liquids (NGLs) recovery plants

A method for production of liquid natural gas (LNG) at natural gas liquids (NGLs) recovery plants and improvements to recovery of natural gas liquids from natural gas using LNG, comprising:

• providing a pressurized natural gas stream to an NGL recovery plant, the pressurized natural gas stream being diverted from a natural gas pipeline at a pipeline pressure;
• operating a de-methanizer column of the NGL recovery plant to produce an overhead stream and an NGL product stream from the pressurized natural gas stream, wherein operating the de-methanizer column comprises at least controlling a temperature within the de-methanizer column;
• passing at least a portion of the overhead stream of the de-methanizer column through a carbon dioxide removal unit;
• producing LNG at a pressure and temperature below which carbon dioxide condenses by reducing the pressure and temperature of the output of the carbon dioxide removal unit;
• transferring a portion of the produced LNG to storage;
• and
• using a further portion of the produced LNG as an external cooling source to condition an input stream to the de-methanizer column by directly mixing the portion of the produced LNG with an input stream, the input stream being derived from the pressurized natural gas stream,
• wherein the temperatures to produce the NGL product stream and the produced LNG are exclusively derived by reducing the pressure of natural gas from the pressurized natural gas stream within the NGL recovery plant.