A cryogenic fluid purification device comprising: a first container defining an interior region; a second container defining an interior region in fluid communication with the interior region of the first container; and a cryogenic fluid in contact with an exterior of the second container.

Methods for the production of liquid biogas (LBG) are disclosed. The methods may include the following steps: inflow of crude gas comprising mainly methane and carbon dioxide; removal of trace elements like hydrogen sulphide, siloxanes and VOC's from the crude gas; dehumidification; particle purification; for the production of a treated biogas; separation of carbon dioxide from the treated biogas; condensation of the treated biogas with a low content of carbon dioxide, for the production of LBG with a carbon dioxide content of maximum 100 ppm, preferably at or close to atmospheric pressure the LBG is close to 100% pure methane with a carbon dioxide content of maximum 100 ppm, wherein the separation of carbon dioxide from the treated biogas involves freezing carbon dioxide in the treated biogas.

A liquefier device which may be a retrofit to an air separation plant or utilized as part of a new design. The flow needed for the liquefier comes from an air separation plant running in a maxim oxygen state, in a stable mode. The three gas flows are low pressure oxygen, low pressure nitrogen, and higher pressure nitrogen. All of the flows are found on the side of the main heat exchanger with a temperature of about 37 degrees Fahrenheit. All of the gases put into the liquefier come out as a subcooled liquid, for storage or return to the air separation plant. This new liquefier does not include a front end electrical compressor, and will take a self-produced liquid nitrogen, pump it up to a runnable 420 PSIG pressure, and with the use of turbines, condensers, flash pots, and multi pass heat exchangers. The liquefier will make liquid from a planned amount of any pure gas oxygen or nitrogen an air separation plant can produce.

A process for separating carbon dioxide from a waste gas of a fluid catalytic cracking installation including converting at least a portion of the carbon monoxide of the waste gas into carbon dioxide to form a flow enriched in carbon dioxide, separating at least a portion of the flow enriched in carbon dioxide to form a gas enriched in carbon dioxide and depleted in nitrogen and a gas rich in nitrogen and depleted in carbon dioxide, and at least a portion of the gas enriched in carbon dioxide and depleted in nitrogen is separated by way of separation at a temperature of less than 0 C. to form a fluid rich in carbon dioxide and a fluid depleted in carbon dioxide and sending a gas containing at least 90% oxygen to combustion.