Abstract: The inventive process and associated apparatus are ideally suited for the small-scale liquefaction of natural gas. The current invention provides a methodology and apparatus for the liquefaction of normally gaseous material, most notably natural gas, which reduces both the number of process vessels required and also the associated space requirements over convention apparatus while resulting in only a slight decrease in process efficiency.

Abstract: A process for simultaneously, cryogenically separating natural gas liquids from a lean natural gas stream and a rich natural gas stream; including, compressing the lean gas feed, cooling the compressed lean gas feed, separating the cooled lean gas feed to form a vapor phase and a liquid phase, expanding the vapor phase lean gas feed, separating the expanded vapor phase lean gas feed to form a second vapor phase and a second liquid phase, fractionating the second vapor phase lean gas feed to form a methane-enriched, low pressure bottoms fraction and a nitrogen-enriched, high pressure overhead fraction, flashing a portion of the methane-enriched bottoms fraction and passing the same in countercurrent, indirect heat exchange with the nitrogen-enriched overhead fraction, to cool the same and produce a vapor phase nitrogen-enriched product and a liquid phase reflux for the fractionator, passing the remainder of the methane-enriched bottoms fraction, the flashed methane-enriched bottoms fraction and the vapor phase

Abstract: In a system for liquefying natural gas containing more than about 1.5 percent nitrogen in which the natural gas is cooled by refrigeration and heat exchange with initial flashing of liquid at a pressure to remove substantialy all of the container nitrogen and with additional stages of flashing of liquid with low pressure flash liquid being passed to liquid natural gas storage and flashed vapors used for heat exchange, recompressed, and combined with the incoming feed the energy requirements of the system are improved by stabilizing the amount of nitrogen recycle in the system by stripping nitrogen from the initial vapor flash with overhead from the stripping heat exchanged within the system to recover its refrigeration and then yielded from the system and with the liquid from the stripping, recycled to the liquid from the initial flashing.

Abstract: A process for liquefying a natural gas, having a pressure above atmospheric pressure, in which a feed gas is cooled to sequentially lower temperatures, by passing the gas through a plurality of cooling stages, in indirect heat exchange with at least one refrigerant, until the gas is substantially completely condensed in the last of the cooling stages, a fuel gas fraction is withdrawn from the liquefied gas in an amount proportional to the amount of feed gas passing through the cooling stages and, thereafter, the pressure of the remaining liquefied gas is reduced to essentially atmospheric pressure. Apparatus for carrying out the process is also described.