Adsorption and isomerization of normal and mono-methyl paraffins
AssigneeUop LLC
InventorWarren K. Volles
Life of this patent
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Abstract
This invention relates to processes for separating by adsorption lower octane normal and mono-methyl paraffins from hydrocarbon feeds containing normal, mono-methyl and more highly branched paraffin fractions and isomerizing the normal and mono-methyl paraffins to produce higher octane isopentane and more highly branched paraffins. Adsorbents capable of adsorbing both normal and mono-methyl paraffins are used either alone or in combination with adsorbents capable of adsorbing normal paraffins but not mono-methyl paraffins. Isopentane, although adsorbed along with the mono-methyl paraffins, is preferentially eluted from the adsorber and recovered as an adsorption effluent.
Claims26
A process for separating isopentane and di-methyl branched hexane paraffins from a hydrocarbon feed containing isopentane, mono-methyl branched hexane paraffins, and di-methyl branched hexane paraffins, which comprises the steps of:
- (a) passing said hydrocarbon feed through an adsorber bed containing a microporous molecular sieve adsorbent having pores of an elliptical cross-section with pore dimensions between about 5.0 and 5.5 along the minor axis and between about 5.5 and 6.0 along the major axis, wherein mono-methyl branched hexane paraffins and isopentane are adsorbed and isopentane is preferentially desorbed during continued adsorption to provide a mass transfer zone having isopentane concentrated at the leading edge thereof;
- (b) removing an essentially non-adsorbed fraction comprising di-methyl branched hexane paraffins from said adsorber bed as a portion of an adsorption effluent;
- (c) eluting at least a portion of the mass transfer zone which comprises isopentane from said adsorber bed as another portion of the adsorption effluent;
- and
- (d) desorbing mono-methyl branched hexane paraffins from said adsorber bed to regenerate the adsorber bed and produce a desorption effluent comprising mono-methyl branched hexane paraffins.
A process for separating isopentane from a hydrocarbon feed containing a pentane fraction which comprises the steps of:
- (a) passing said hydrocarbon feed through an adsorber bed containing a microporous molecular sieve having elliptical pores with cross-sectional pore dimensions in the range of approximately 4.5 to 5.5, wherein isopentane and normal pentane are adsorbed and isopentane is preferentially desorbed during continued adsorption to provide a mass transfer zone having isopentane concentrated at the leading edge thereof;
- (b) eluting at least a portion of the mass transfer zone, which comprises isopentane from said adsorber bed as an adsorption effluent;
- and
- (c) desorbing adsorbed components from said adsorber bed to regenerate the adsorber bed and produce a desorption effluent comprising said components.
A process for separating isopentane and di-methyl branched hexane paraffins from a hydrocarbon feed comprising isopentane, normal pentane, normal hexane, mono-methyl branched hexane paraffins and di-methyl branched hexane paraffins which comprises the steps of:
- (a) passing said hydrocarbon feed to a first adsorber bed containing adsorbent having pore dimensions sufficient to allow adsorption of normal paraffins while essentially excluding mono-methyl and di-methyl branched paraffins, wherein normal pentane and normal hexane are adsorbed to provide a de-normalized feed at least partially depleted in normal paraffins and comprising isopentane, mono-methyl branched hexane paraffins and di-methyl branched hexane paraffins;
- (b) passing said de-normalized feed through a second adsorber bed containing adsorbent having pore dimensions sufficient to allow adsorption of isopentane and mono-methyl branched hexane paraffins while essentially excluding di-methyl branched hexane paraffins, wherein isopentane and mono-methyl branched hexane paraffins are adsorbed and isopentane is preferentially desorbed during continued adsorption to provide a mass transfer zone having isopentane concentrated at the leading edge thereof;
- (c) removing an essentially non-adsorbed fraction comprising di-methyl branched hexane paraffins from said second adsorber bed as a portion of an adsorption effluent;
- (d) eluting at least a portion of the mass transfer zone which comprises isopentane from said adsorber bed as another portion of the adsorption effluent;
- and
- (e) desorbing mono-methyl branched hexane paraffins from said second adsorber bed and normal pentane and hexane from said first adsorber bed.
Dependencies are inferred from the claim text.