Device and technological method for LNG production through recycling synthesis ammonia tail gas

The invention belongs to a device and technological method for LNG production through recycling synthesis ammonia tail gas. The device comprises a gas inlet buffer tank which is connected with a first virgin gas inlet of a first heat exchanger through a pipeline. A first virgin gas outlet of the first heat exchanger is respectively connected with an expansion end inlet of a pressurization expansion machine and a virgin gas inlet of a reboiler through pipelines. An expansion end outlet of the pressurization expansion machine is connected with a virgin gas inlet of a gas-liquid separator through a pipeline. The virgin gas inlet of the reboiler is communicated with a virgin gas outlet of the reboiler. The virgin gas outlet of the reboiler sequentially passes through a second virgin gas inlet and a second virgin gas outlet of a second heat exchanger and a third throttle valve and then is connected with an inlet in the upper portion of a rectifying tower. The device and technological method have the advantages of