Patent ID: 11493239

Abstract:
A method for efficiently reducing the energy required to convert natural gas from a natural gas pressure letdown facility at high pressure and pipeline/wellhead temperature to liquid natural gas in close proximity to/collocation with a natural gas pressure letdown/regulation facility using Non-Freezing Vortex Tubes (U.S. Pat. No. 5,749,231) in arrangement with indirect contact heat exchangers. The Non-Freezing Vortex Tubes separate the inlet natural gas into hot flow and cold flow outlet natural gas flows. One portion of the natural gas flow from the high-pressure transmission line/gas wellhead is directed through the Non-Freezing Vortex Tube and the cold outlet flow of the natural gas is directed to the indirect contact heat exchanger(s) to act as the cooling medium. The liquid natural gas plant's required natural gas flow is directed at the existing pipeline/wellhead gas pressure through the heat exchanger and cooled. The already cooled natural gas flow is directed to a turbo expander and refrigeration cold box system where it is further chilled and converted into liquid natural gas at −162° C.