Coke oven heating exhaust gas external circulation system

The utility model relates to a coke oven heating waste gas external circulation system which is respectively arranged on the machine side and the coke side of a coke oven and consists of a waste gas leading-out pipe, an air heater, a waste gas main pipe, a waste gas branch pipe and a pneumatic waste gas exchange brace system, one end of the exhaust gas lead-out pipe is connected with the coke ovenexhaust gas flue, and the other end is connected with an air inlet of the air heater of which an air outlet is connected with the exhaust gas main pipe; the waste gas main pipe is horizontally arranged, is provided with a plurality of waste gas branch pipes, and is connected with the coke oven waste gas exchange shutters in a one-to-one correspondence manner; a waste gas regulating valve and a waste gas exchange valve are sequentially arranged on the waste gas branch pipe in the waste gas flowing direction; and a wrench handle is arranged on a shaft head of the waste gas exchange valve and isconnected with a brace in