Removal of C3 lights from LPG feedstock to butane isomerization unit

A method of processing a hydrocarbon mixture, the method comprising:

• processing a first hydrocarbon mixture comprising propane, n-butane, and isobutane in an isomerization unit at a temperature of 125 to 175° C. to isomerize the n-butane to produce isobutane;
• separating a mixture from the isomerization unit by a de-isobutanizer to produce and form an isomerization unit effluent comprising propane, isobutane, or combinations thereof and an unreacted n-butane stream;
• separating a second hydrocarbon mixture comprising propane, n-butane, and isobutane in a second separation unit to produce an overhead stream comprising primarily propane and isobutane, collectively, and a first C4 stream comprising n-butane;
• cracking the first C4 stream and/or the unreacted n-butane stream in a first steam cracking unit to produce propylene, ethylene, and benzene;
• combining the overhead stream and the isomerization unit effluent to form a combined stream;
• separating the combined stream to form a C3 stream comprising primarily propane and a second C4 stream comprising isobutane;
• dehydrogenating the isobutane of the second C4 stream in a dehydrogenation unit to produce isobutene in a dehydrogenation unit effluent;
• and
• reacting, in an etherification unit, the isobutene of the dehydrogenation unit effluent with an alkanol in the presence of a catalyst to produce an alkyl tert-butyl ether in a product stream.