Vacuum swing adsorption process for separating propylene from propane
AssigneeUop LLC
InventorsLinda S. Cheng, Stephen T. Wilson
Life of this patent
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Abstract
A vacuum swing adsorption process is provided for the separation of propylene from a feedstream comprising propylene and propane using an adsorbent comprising AlPO-14 to produce a high purity propylene product stream at high recovery. The vacuum swing adsorption process of the present invention can be employed in a variety of petroleum refining and petrochemical processes to purify and separate propylene from mixtures of propylene and propane alone or in combination with fractionation.
Claims9
A vacuum swing adsorption process For the separation of propylene from a feedstream comprising propylene and propane to produce a high purity propylene product, said process comprising:
- a) passing the feedstream at effective adsorption conditions in an adsorption step to a first adsorption bed of a plurality of adsorption beds, each of said adsorption beds containing a selective adsorbent comprising AlPO-14 to produce a raffinate stream, comprising propane;
- b) terminating the passing of the feedstream to the first adsorption bed and co-currently purging the first adsorption bed at a co-purge pressure essentially equal to an adsorption pressure with a recycle stream to provide a purge gas stream comprising propane;
- c) co-currently venting the first adsorption bed to a vent pressure and withdrawing a vent stream;
- d) co-currently depressurizing the first adsorption bed to a provide-purge pressure lower than the vent pressure to produce a provide-purge gas and passing the provide-purge gas to another adsorption bed:
- e) further co-currently depressurizing the first adsorption bed in a first equalization step to an equalization pressure lower than the provide-purge pressure to produce an equalization gas and passing the equalization gas to another adsorption bed;
- f) counter-currently depressurizing the first adsorption bed in an evacuation step to a desorption pressure to provide a first desorption stream comprising propylene;
- g) counter-currently purging the first adsorption bed with a vacuum purge gas stream from another adsorption bed to produce a second desorption stream comprising propylene;
- h) counter-currently repressurizing the first adsorption bed in a second equalization step to about the equalization pressure;
- i) further counter-currently repressurizing the first adsorption bed to about the adsorption pressure with at least a portion of the raffinate stream;
- j) compressing the first desorption stream and the second desorption stream to provide the high purity propylene product;
- k) recycling at least a portion of the high purity propylene product to provide the recycle stream;
- and
- l) repeating steps (a) to (k) for each of the adsorption beds to provide a continuous process.
Dependencies are inferred from the claim text.