Cyclic catalytic hydrocarbon conversion process with reduced chloride emissions

A sorptive method for recovering chlorine or hydrogen chloride from the flue gas stream of a cyclic regeneration operation of a hydrocarbon reforming process having at least three reforming catalyst beds, such that, in each step of each cycle in a series of successive cycles, one reforming catalyst bed operates in hydrocarbon reforming mode, another reforming catalyst bed operates in sorption mode, and yet another reforming catalyst bed operates in regeneration mode, said method comprising:

• (a) passing a feed stream comprising hydrocarbons having a boiling range of from 180 to 400.degree. F. to a first reforming catalyst bed containing reforming catalyst comprising alumina, platinum metal, and chloride, reforming said hydrocarbons in said first reforming catalyst bed at reforming conditions sufficient to deposit coke on reforming catalyst in said first reforming catalyst bed, withdrawing an exit stream comprising reformed hydrocarbons from said first reforming catalyst bed, passing said exit stream to a first separation zone, and recovering from said first separation zone a product stream comprising reformed hydrocarbons;
• (b) passing a regenerant stream comprising nitrogen, oxygen, and at least one of hydrogen chloride and chlorine to a second reforming catalyst bed containing reforming catalyst comprising chloride and having coke deposited thereon, removing at least a portion of the coke and the chloride at regeneration conditions from reforming catalyst in said second reforming catalyst bed, and withdrawing a flue gas stream comprising nitrogen and at least one of chlorine and hydrogen chloride from said second reforming catalyst bed;
• (c) cooling said flue gas stream to produce a cooled flue gas stream, passing said cooled flue gas stream to a third reforming catalyst bed containing reforming catalyst having coke deposited thereon, removing a portion of at least one of chlorine and hydrogen chloride from said cooled flue gas stream by sorption on reforming catalyst in said third reforming catalyst bed, and withdrawing an effluent stream comprising nitrogen and having a decreased concentration of chlorine or hydrogen chloride relative to said cooled flue gas stream;
• and
• (d) periodically shifting the functions of said first, second, and third reforming catalyst beds by operating said first reforming catalyst bed to function as said third reforming catalyst bed in Step (c), operating said third reforming catalyst bed to function as said second reforming catalyst bed in Step (b), and operating said second reforming catalyst bed to function as said first reforming catalyst bed in Step (a).

A sorptive method for recovering chloro-species from an outlet stream of a cyclic regeneration operation of a hydrocarbon conversion process, said method comprising:

• (a) contacting hydrocarbons with hydrocarbon conversion catalyst in a first catalyst bed to convert hydrocarbons;
• (b) at least partially regenerating hydrocarbon conversion catalyst containing chloride and removing at least a portion of the chloride from hydrocarbon conversion catalyst in a second catalyst bed at regeneration conditions, and withdrawing an outlet stream comprising chloro-species from said second catalyst bed;
• (c) passing at least a portion of said outlet stream comprising chloro-species to a third catalyst bed containing hydrocarbon conversion catalyst, sorbing at least a portion of the chloro-species in said at least a portion of said outlet stream on hydrocarbon conversion catalyst in said third catalyst bed at sorption conditions, said sorption conditions comprising a sorption temperature of from 150.degree. F. to 900.degree. F., and withdrawing from said third catalyst bed an effluent stream having a decreased concentration of chloro-species relative to said at least a portion of said outlet stream;
• and
• (d) periodically shifting the functions of said first, second, and third catalyst beds by operating said first catalyst bed to function as said third catalyst bed in Step (c), operating said third catalyst bed to function as said second catalyst bed in Step (b), and operating said second catalyst bed to function as said first catalyst bed in Step (a).