Method for the removal and recovery of mononuclear and polynuclear aromatic co-products produced in a hydrocarbon dehydrogenation reaction zone

摘要

Polynuclear aromatic compounds (PNA's) produced as a by-product in a hydrocarbon dehydrogenation zone are removed and recovered by admixing the effluent from the dehydrogenation zone with a recycle stream containing mononuclear aromatic compounds (MNA's) and the resulting admixture is contacted with an adsorbent to reduce the concentration of MNA's and PNA's and to produce a stream comprising dehydrogenated hydrocarbons and dehydrogenatable hydrocarbons. The spent adsorbent recovered from the adsorption step containing MNA's and PNA's is regenerated by contacting with a hot hydrogen-rich gas to recover at least a portion of the MNA's and PNA's and to thereby regenerate the spent adsorbent. The hydrocarbon-containing effluent from the regeneration step is then separated into a MNA's -containing stream and a PNA's-containing stream and at least a portion of the MNA's-containing stream is recycled to the mixing step. <IMAGE>