摘要:
A treatment process for a hydrogen-containing off-gas stream from a refinery, petrochemical plant or the like. The process includes three separation steps: condensation, membrane separation and hydrocarbon fraction separation. The membrane separation step is characterized in that it is carried out under conditions at which the membrane exhibits a selectivity in favor of methane over hydrogen of at least about 2.5.
摘要:
An improved process for separating hydrogen from hydrocarbons. The process includes a pressure swing adsorption step, a compression/cooling step and a membrane separation step. The membrane step relies on achieving a methane/hydrogen selectivity of at least about 2.5 under the conditions of the process.
摘要:
Processes for providing improved methane removal and hydrogen reuse in reactors, particularly in refineries and petrochemical plants. The improved methane removal is achieved by selective purging, by passing gases in the reactor recycle loop across membranes selective in favor of methane over hydrogen, and capable of exhibiting a methane/hydrogen selectivity of at least about 2.5 under the process conditions.
摘要:
A membrane separation process for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. We have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen.
摘要:
A membrane separation process for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. We have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen.
摘要:
A membrane process for separating chlorine from chlorine-containing gas streams is disclosed. The process employs a permselective membrane that is selective to chlorine and is stable in the long-term presence of chlorine. The process can be used to treat tail-gas from chlor-alkali plants, for example.
摘要:
A process for treating natural gas or other methane-rich gas to remove excess nitrogen and optionally excess carbon dioxide, water vapor or hydrogen sulfide. The invention relies on gas separation by membranes, using nitrogen/methane selective membranes. The membranes are characterized by having the capability to exhibit a nitrogen/methane selectivity between about 2 and 5 at a temperature higher than about −25° C. The gas may be brought to pipeline specification for nitrogen, and acid gases if present, without requiring the use of amine scrubbing or other acid gas removal technique.
摘要:
A process for separating condensable organic components from gas streams. The process makes use of a membrane made from a polymer material that is glassy and that has an unusually high free volume within the polymer material.
摘要:
A process for treating natural gas or other methane-rich gas to remove excess nitrogen and carbon dioxide simultaneously. The invention relies on membrane separation using nitrogen/methane and carbon dioxide/methane selective membranes. The gas can typically be brought to pipeline specification for both components, without requiring the use of amine scrubbing or other acid gas removal technique. Where water vapor or hydrogen sulfide is present in the raw gas, these contaminants may also be removed to meet pipeline specification in a single operation.
摘要:
A process for separating hydrogen from a multicomponent gas mixture containing hydrogen and a hydrocarbon, using gas-separation membranes selective for hydrogen over the hydrocarbon. The membranes use a selective layer made from a polymer having repeating units of a fluorinated polymer, and demonstrate good resistance to plasticization by the organic components in the gas mixture under treatment, and good recovery after exposure to liquid aromatic hydrocarbons.