US 6,293,999 B1 · Process for separating propylene from propane

Abstract

A process is provided for the concentration and recovery of propylene from propane using an adsorbent comprising AlPO-14 at adsorption temperatures less than 120° C. and an adsorption pressure comprising a propylene partial pressure between about 0.5 bar and about 4 bar. The AlPO-14 adsorbent can be employed as a selective adsorbent for the separation of propylene from mixtures thereof with propane in vacuum swing adsorption processes, thermal swing adsorption processes, and combinations thereof. A simulated moving bed process using vacuum swing adsorption is used to remove propylene from a C3 hydrocarbon stream comprising propylene and propane and recover a high purity propylene product at a high recovery rate. The simulated moving bed 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.

Claims15

Dependent claims

A process for adsorptive separation of propylene from a feedstream comprising propylene and propane, said process comprising:

a) passing the feedstreani at an effective sorption temperature less than 120° C. and a sorption pressure to a sorption zone wherein said sorption zone comprises AlPO-14, to adsorb at least a portion of the propylene and withdrawing an unadsorbed stream comprising propane;
and
b) desorbing at least a portion of the propylene from the sorption zone and withdrawing a desorbed stream.

A simulatedmoving bed process for the purification of propylene from a feedstream comprising propane and propylene, said process comprising:

a) introducing a feedstream and a first co-purge effluent stream at an effective adsorption pressure and adsorption temperature to a first adsorption bed of a plurality of at least tour adsorption beds containing an AlPO-14 small pore aluminophosphate adsorbent for the selective adsorption of propylene, said first co-purge effluent stream being withdrawn from a second adsorption bed and withdrawing a raffinate stream comprising propane from the first adsorption bed;
b) co-purging a second adsorption bed with a second co-purge effluent stream withdrawn from a third adsorption bed and withdrawing the first co-purge effluent stream;
c) co-purging the third adsorption bed with a compressed recycle stream and withdrawing the second co-purge effluent stream;
d) isolating and counter-currently depressurizing a fourth adsorption bed to an effective desorption pressure in an evacuation step to recover a propylene product stream;
e) recompressing at least a portion of the propylene product stream to provide the compressed recycle stream,
f) counter-currently repressurizing the fourth adsorption bed with at least a portion of the raffmate stream to provide a repressurized fourth adsorption bed;
and
g) advancing the fcedstream to the repressurized fourth adsorption bed and switching the positions among said plurality of adsorption beds such that each of said adsorption beds effectively advances by one adsorption bed with respect to the first adsorption bed to provide a continuous process.

5 more elements

Dependencies are inferred from the claim text.

Process for separating propylene from propane

Life of this patent

Process for separating propylene from propane

Life of this patent

Abstract

Claims15