NOVELTY - Pyrolysis furnace comprises internal cylinder, external cylinder, fire grate, discharge hole, exit pipe, cover arranged on internal cylinder, feed port arranged on cover, and air inlet. The internal cylinder has bottom connected with discharge hole and uniformly distributed with several small vent holes; annular air passage formed between external cylinder and internal cylinder; exit pipe arranged on external cylinder and is formed on air outlet gallery with air passage; small vent holes; and ventilated flame retardant coating.    USE - Pyrolysis furnace used for comprehensive conversion device of agricultural wastes used in factories, villages, or towns.    ADVANTAGE - The pyrolysis furnace has high conversion efficiency for converting agricultural wastes to biological mixed gas or biomass charcoal.    DETAILED DESCRIPTION - Pyrolysis furnace comprises internal cylinder, external cylinder, fire grate, discharge hole, exit pipe, cover arranged on internal cylinder, feed port arranged on cover, and air inlet. The internal cylinder has bottom connected with discharge hole and uniformly distributed with several small vent holes; annular air passage formed between external cylinder and internal cylinder; exit pipe arranged on external cylinder and is formed on air outlet gallery with air passage; small vent holes; and ventilated flame retardant coating. The fire grate is arranged between internal cylinder and discharge hole. The cover has outer shape which is cone-shaped and has distributing assembly. The distributing assembly is scraper blade distributing assembly or cylinder distributing assembly comprising motor, spindle and scraper blade. The middle of cover is arranged with spindle having upper end outside of cover connected with motor, and lower end spindle inside the cover connected with scraper blade. The outer cylinder is annular water jacket formed by inner and outer walls. The upper and lower of outside wall of annular water jacket are separately arranged with water inlet pipe and water outlet pipe. The upper end surface and lower end surface are arranged with insulating layers.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of pyrolysis furnace.