Systems and methods for producing propylene using an MTBE synthesis raffinate are disclosed. An MTBE synthesis raffinate stream first passes through a molecular sieve to separate n-butane and isobutane from the rest of C.sub.4 hydrocarbons of the MTBE synthesis raffinate. The 1-butene in the rest of C.sub.4 hydrocarbons of the MTBE synthesis raffinate is then isomerized to form 2-butene. Therefore, the concentration of 2-butene in the subsequent propylene production process increases due to the separation of n-butane and isobutane and the isomerization of 1-butene, resulting in an improved reaction rate and reaction efficiency for propylene production.

Systems and methods for producing propylene using an MTBE synthesis raffinate are disclosed. An MTBE synthesis raffinate stream first passes through a molecular sieve to separate n-butane and isobutane from the rest of C.sub.4 hydrocarbons of the MTBE synthesis raffinate. The 1-butene in the rest of C.sub.4 hydrocarbons of the MTBE synthesis raffinate is then isomerized to form 2-butene. Therefore, the concentration of 2-butene in the subsequent propylene production process increases due to the separation of n-butane and isobutane and the isomerization of 1-butene, resulting in an improved reaction rate and reaction efficiency for propylene production.

A method of producing a fuel additive includes passing a feed stream comprising C4 hydrocarbons through a methyl tertiary butyl ether unit producing a first process stream; passing the first process stream through a selective hydrogenation unit producing a second process stream; passing the second process stream through an isomerization unit producing a third process stream; and passing the third process stream through a hydration unit producing the fuel additive and a recycle stream.

A method of producing a fuel additive includes passing a feed stream comprising C4 hydrocarbons through a methyl tertiary butyl ether unit producing a first process stream; passing the first process stream through a selective hydrogenation unit producing a second process stream; passing the second process stream through an isomerization unit producing a third process stream; and passing the third process stream through a hydration unit producing the fuel additive and a recycle stream.

A process increases the concentration of normal paraffins in a feed stream comprising separating a naphtha feed stream into a normal paraffin rich stream and a non-normal paraffin rich stream. A naphtha feed stream may be separated into a normal paraffin stream and a non-normal paraffin stream. An isomerization feed stream is taken from the non-normal paraffin stream and isomerized over an isomerization catalyst to convert non-normal paraffins to normal paraffins and produce an isomerization effluent stream. The isomerization effluent stream may be separated into a propane stream and a C4+ hydrocarbon stream optionally in a single column. The C4+ hydrocarbon stream may be recycled to the step of separating a naphtha feed stream.

A process increases the concentration of normal paraffins in a feed stream comprising separating a naphtha feed stream into a normal paraffin rich stream and a non-normal paraffin rich stream. A naphtha feed stream may be separated into a normal paraffin stream and a non-normal paraffin stream. An isomerization feed stream is taken from the non-normal paraffin stream and isomerized over an isomerization catalyst to convert non-normal paraffins to normal paraffins and produce an isomerization effluent stream. The isomerization effluent stream may be separated into a propane stream and a C4+ hydrocarbon stream optionally in a single column. The C4+ hydrocarbon stream may be recycled to the step of separating a naphtha feed stream.

Processes for producing olefins include passing a hydrocarbon feed to a hydrocarbon cracking unit that cracks the hydrocarbon feed to produce a cracker effluent, passing the cracker effluent to a cracker effluent separation system that separates the cracker effluent to produce at least a cracking C4 effluent including 1-butene, 1,3-butadiene, and isobutene, passing the cracking C4 effluent to an SHIU that contacts the cracking C4 effluent with hydrogen in the presence of a selective hydrogenation catalyst to produce a hydrogenation effluent having a 2-butenes concentration greater than or equal to the sum of the concentrations of 1-butene and isobutene. The processes include passing the hydrogenation effluent to a metathesis unit that contacts the hydrogenation effluent with a metathesis catalyst and a cracking catalyst downstream of the metathesis catalyst to produce a metathesis reaction effluent comprising at least propene.

Processes for producing olefins include passing a hydrocarbon feed to a hydrocarbon cracking unit that cracks the hydrocarbon feed to produce a cracker effluent, passing the cracker effluent to a cracker effluent separation system that separates the cracker effluent to produce at least a cracking C4 effluent including 1-butene, 1,3-butadiene, and isobutene, passing the cracking C4 effluent to an SHIU that contacts the cracking C4 effluent with hydrogen in the presence of a selective hydrogenation catalyst to produce a hydrogenation effluent having a 2-butenes concentration greater than or equal to the sum of the concentrations of 1-butene and isobutene. The processes include passing the hydrogenation effluent to a metathesis unit that contacts the hydrogenation effluent with a metathesis catalyst and a cracking catalyst downstream of the metathesis catalyst to produce a metathesis reaction effluent comprising at least propene.

A process increases the concentration of non normal paraffins in a feed stream comprising separating a naphtha feed stream into a normal paraffin rich stream and a non-normal paraffin rich stream. The non-normal paraffin rich stream is isomerized over an isomerization catalyst to convert non-normal paraffins to normal paraffins, hydrocrack C5+ hydrocarbon to C2-C4 paraffins and produce an isomerization effluent stream. The isomerization effluent stream is separated into a C3− off gas, C4 rich stream and C5+ stream that is recycled to the naphtha feed stream. A depentanizer column may be positioned to either remove C6+ from the naphtha feed stream or from a bottoms stream from a stabilizer column. The amount of C2-C4 paraffins that are provided is increased from about 55% to as much as 77% and even more with further modifications including operating at higher temperatures or increasing the volume of catalyst.

A process increases the concentration of non normal paraffins in a feed stream comprising separating a naphtha feed stream into a normal paraffin rich stream and a non-normal paraffin rich stream. The non-normal paraffin rich stream is isomerized over an isomerization catalyst to convert non-normal paraffins to normal paraffins, hydrocrack C5+ hydrocarbon to C2-C4 paraffins and produce an isomerization effluent stream. The isomerization effluent stream is separated into a C3− off gas, C4 rich stream and C5+ stream that is recycled to the naphtha feed stream. A depentanizer column may be positioned to either remove C6+ from the naphtha feed stream or from a bottoms stream from a stabilizer column. The amount of C2-C4 paraffins that are provided is increased from about 55% to as much as 77% and even more with further modifications including operating at higher temperatures or increasing the volume of catalyst.