Abstract: The present invention provides a method and apparatus for removing acetylene from a gasoeus mixture comprising hydrogen, methane, ethane, ethylene, acetylene, propane, propylene, butane, butenes, butadiene, and other C4 or higher hydrocarbons. The method of the invention utilizes a front-end acetylene removal unit (“ARU”) located after a charge gas compressor in which acetylene is selectively reduced. The method of the invention achieves selective reduction of acetylene by using a proprietary Chevron Phillips E series palladium based catalyst. The method of the invention also utilizes a novel startup procedure, a novel emergency shutdown procedure, a novel maximum cool down procedure, and a novel carbon monoxide monitoring procedure.

Abstract: An injection molded finish portion of a container preform has an annular wall with an end sealing surface. A set of ratchet teeth are located at a lower end of the annular wall on a flange having upper and lower surfaces including radially inward edges coterminous with the annular wall. A threaded portion is located below the sealing surface and above the ratchet teeth that includes sets of inclined threads extending part way around the annular wall, the threads having crest portions that terminate at planes tangent to the annular wall along parting lines on opposite sides of the finish. Lugs project outward from the annular wall in the vicinity of the parting lines to ensure correct interaction between the ratchet teeth and a cooperating flexible closure.