Abstract: A method and apparatus for separating a compressed, biologically generated, feed gas stream comprising methane, carbon dioxide, water vapour and impurities including volatile non-methane organic compounds. The method comprises purifying the compressed, biologically generated, feed stream by adsorption to remove the volatile non-methane organic compounds and the water vapour and to form a purified feed stream. The purified feed stream is separated by membranes to produce a first product gas stream enriched in methane and an intermediate gas stream enriched in carbon dioxide. Part of the first product gas stream is withdrawn and mixed with at least part of the intermediate gas stream to form a second product gas stream comprising methane and carbon dioxide.

Abstract: A method for removing contaminants from a natural gas stream such as a biogas/landfill gas stream. The natural gas stream is fed to a first adsorption unit for removal of certain contaminants and then to a second adsorption unit for the removal of additional contaminants. Alternatively, a membrane stage may be employed between the adsorption units. The method utilizes the external purge to enhance pressure swing adsorption working capacity so that the vacuum level required for regeneration is not as high.

Abstract: One or more continuous rotary contactors, also known as adsorbent wheels, containing adsorbent materials are employed to dry, purify or separate components from a gas stream. The invention has particular application in treating air prior to cryogenic air separation operations.

Abstract: Using a high pressure rotary adsorbent wheel, a high value compressed gas feed can be purified by concentrating the impurity such as water, condensing it out, before final purification. Instead of exhausting gas from the system, the effluent can be put back into the feed at a point prior to condensation of the high value gas feed, and therefore the entire feed is purified without any high value gas feed going into a waste stream.

Abstract: The present invention provides a food processing system and method for refrigerating articles of food. The food processing system includes at least two cooling stages formed by a cryogenic freezer and a hydrocooler. The cryogenic freezer receives the articles of food and transfers heat from the articles of food to the cryogen so that the articles of food are refrigerated. After the transfer of heat from the articles of food to the cryogen, the cryogen boils off to form cryogenic vapor. The hydrocooler receives the articles of food prior to the cryogenic freezer and transfers heat from the articles of food to supplied cooling water. Such heat transfer reduces the quantity of cryogen required to refrigerate the articles of food. Additionally, an eductor is connected to a pump and to vent line from the cryogenic freezer.