Process for conversion of butane to gasoline

A hydrocarbon conversion process which comprises the steps of:

• (a) passing a feed stream comprising a butane and a hereinafter characterized recycle stream into a dehydrogenation zone operated at butane dehydrogenation conditions and thereby forming a dehydrogenation zone effluent stream comprising hydrogen, a butane and a butylene;
• (b) passing the entire dehydrogenation zone effluent stream into a catalytic condensation zone operated at conditions which effect the conversion of butylene into C.sub.8 and C.sub.12 hydrocarbons and thereby forming a catalyst condensation zone effluent stream which comprises hydrogen, a butane, C.sub.8 hydrocarbons and C.sub.12 hydrocarbons;
• (c) passing the catalytic condensation zone effluent stream, a first absorber bottoms stream and a stripping column overhead stream into a vapor-liquid separation zone;
• (d) passing a vapor stream comprising hydrogen and a butane and which is withdrawn from the vapor-liquid separation zone into a first absorber and contacting the vapor stream at absorption-promoting conditions with a first lean liquid hydrocarbon stream comprising a butane, C.sub.8 and C.sub.12 hydrocarbons and thereby producing the first absorber bottoms stream, which comprises a butane and C.sub.8 hydrocarbons, and a first absorber vapor stream comprising hydrogen, a butane and C.sub.8 hydrocarbons;
• (e) passing a liquid stream comprising C.sub.8 and C.sub.12 hydrocarbons and which is withdrawn from the vapor-liquid separation zone into a stripping column operated at conditions which effect the separation of the liquid stream into a stripping column overhead stream comprising hydrogen and a butane and a stripping column bottoms stream which comprises a butane, C.sub.8 hydrocarbons and C.sub.12 hydrocarbons;
• (f) passing a first portion of the stripping column bottoms stream into the first absorber as the previously specified first lean liquid hydrocarbon stream, and passing a second portion of the stripping column bottoms stream into a debutanizer column operated at conditions which effect the separation of the entering hydrocarbons into a debutanizer overhead stream comprising butane and a net debutanizer bottoms stream removed from the process as a product stream which comprises C.sub.8 and C.sub.12 hydrocarbons and is substantially free of butane;
• (g) passing the first absorber vapor stream into a second absorber and contacting the first absorber vapor stream with a second lean liquid hydrocarbon stream at absorption-promoting conditions and thereby producing a second absorber bottoms stream, which comprises a butane and C.sub.8 hydrocarbons, and a second absorber vapor stream which comprises a butane;
• (h) passing the second absorber bottoms stream into the stripping column;
• (i) removing a first portion of the second absorber vapor stream from the process as an off gas stream;
• and,
• (j) passing a first portion of the debutanizer overhead stream into a second absorber as the previously specified second lean liquid hydrocarbon stream, and combining a second portion of the second absorber vapor stream and a second portion of the debutanizer overhead stream with the feed stream as the previously referred to recycle stream of step (a).