TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Plant: The plant further comprises an additional high-pressure separator that is configured to separate the cooled feed gas into a vapor portion and a liquid portion; a third expansion device configured to expand the vapor portion and a fourth expansion device configured to expand the liquid portion upstream of the high-pressure separator; and an additional separator that is configured to separate cooled deethanizer overhead product to form a reflux to the deethanizer and the portion of the deethanizer overhead product. The third expansion device is a turboexpander and the fourth expansion device is JT valve. The first heat exchanger is configured to cool the feed gas and the second heat exchanger is configured to cool the deethanizer overhead product. The first expansion device is a device other than a turboexpander. The second expansion device is a device other than a turboexpander.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The feed gas has a pressure of at least 1000 psig, and the feed gas is cooled and expanded to a pressure of 500-700 psig and a temperature of -30degreesF to -60degreesF. The method further involves a step of separating the cooled feed gas into a vapor portion and a liquid portion, and separately expanding the vapor portion and liquid portion prior the step of separating the vapor phase from the liquid phase; a step of cooling the deethanizer overhead product and separating the deethanizer overhead product to form a reflux to the deethanizer and the portion of the deethanizer overhead product; and a step of using refrigeration content of the vapor phase to provide reflux cooling duty and feed gas cooling duty. The step of expanding the vapor portion is performed in a turboexpander and the step of expanding the liquid portion is performed in a Joule-Thomson (JT valve) (53). The cooling of the at least one of the feed gas and the deethanizer overhead product is performed in two separate heat exchangers. The reflux has a temperature of -30degreesF to -60degreesF. The step of expanding the feed gas and expanding the liquid phase is performed in a device other than a turboexpander. The deethanizer is operated at a pressure of 500-700 psig. EXAMPLE - No suitable example is given.