Abstract: A method for inhibiting the formation of clathrate hydrates in a fluid having hydrate forming constituents is disclosed. More specifically, the method can be used in treating a petroleum fluid stream such as natural gas conveyed in a pipe to inhibit the formation of a hydrate restriction in the pipe. The hydrate inhibitors used for practicing the method are substantially water soluble polymers formed from a cyclic imino ether. Such polymers may be ring closed cyclic imino ether ("CIE") polymers, ring opened CIE polymers, or combinations thereof. Some examples of ring opened CIE polymers include various N-acyl polyalkyleneimines produced by cationic polymerization, such as N-acyl substituted polyethyleneimine, N-acyl substituted polypropyleneimine, N-acyl substituted polybutyleneimine, N-acyl substituted polypentyleneimine and copolymers thereof.

Abstract: A method for inhibiting the formation of clathrate hydrates in a fluid having hydrate forming constituents is disclosed. More specifically, the method can be used in treating a petroleum fluid stream such as natural gas conveyed in a pipe to inhibit the formation of a hydrate restriction in the pipe. The hydrate inhibitors used for practicing the method are substantially water soluble polymers formed from a cyclic imino ether. Some examples of such inhibitors include various N-acyl polyalkyleneimines, such as N-acyl substituted polyethyleneimine, N-acyl substituted polypropyleneimine, N-acyl substituted polybutyleneimine, N-acyl substituted polypentyleneimine and copolymers thereof. Also, such N-acyl substituted polyalkyleneimines can be used in various ratios with other substantially water soluble polymers and copolymers. Preferably, a solvent such as water, brine, alcohol, or mixtures thereof is used to produce an inhibitor solution or mixture to facilitate treatment of the petroleum fluid stream.

Abstract: This invention relates to a closed-loop, multi-stage compression refrigeration system which uses a multi-component refrigerant wherein the compressed refrigerant is partially condensed, and the vapor and liquid streams are separated in a primary separator. The liquid stream passes through several expansion stages, providing a refrigeration duty at each stage. That portion of the refrigerant which is vaporized is recycled to an intermediate stage of the multi-stage compressor. The vapor from the primary separator, which is rich in the light component, is condensed and expanded to the lowest stage of refrigeration, providing maximum refrigeration duty for a given refrigerant composition and compressor suction pressure.