Integrated multi-functional pipeline system for delivery of chilled mixtures of natural gas and chilled mixtures of natural gas and NGLS

A method for producing chilled standard specification and rich gas specification natural gas mixtures within a pipeline system for downstream applications comprising the steps of:

• (a) compressing a natural gas mixture received from a natural gas pipeline to a pressure range of between 2500 psig and 4500 psig to produce a compressed gas mixture;
• (b) storing a volume of the compressed gas mixture in a supercritical state at a pre-expansion pressure range of between 2500 psig and 4500 psig and at a relatively constant temperature;
• (c) expanding the compressed gas mixture using an expansion chilling device in the form of a J-T valve or a turbo expander positioned at a terminus of the pipeline to achieve (i) reduction in pressure to a range of between 600 psig and 1200 psig, and (ii) self chilling through the Joule-Thomson effect to a temperature range of between minus 20° F. to minus 100° F., thereby producing a chilled gas mixture comprising methane, methane and trace ethane, or methane and natural gas liquid, wherein the compressed gas mixture is not externally chilled via a heat exchanger;
• (d) injecting NGLs or make up methane gas into the pipeline during compression, storage, and/or after expansion to adjust the compressed or chilled gas mixture therein so as to avoid instability of undesirable liquid formation and fallout;
• (e) delivering the chilled gas mixture having a pressure of between 600 and 1200 psig and a temperature between minus 20° F. to minus 100° F. from the pipeline system to a downstream destination;
• and
• (f) further liquefying the chilled gas mixture by a liquefied natural gas processing step, or by separation and fractionation.