Hydrogen chloride synthesis furnace

The utility model relates to a hydrogen chloride synthetic furnace which comprises a combustion shell (1), a cooling shell (2) and a graphite block (3), a combustion cavity (11) is formed in the combustion shell (1), an air inlet (12) is formed in the top of the combustion shell (1), a first flange (14) is arranged at the bottom of the combustion shell (1), the top of the cooling shell (2) is fixedly connected with the first flange (14) through a second flange (21), and a cooling cavity (22) is formed in the cooling shell (2). A boiler water inlet (23) and a boiler water outlet (24) are formed in the side wall of the second flange (21), an air outlet (25) is formed in the bottom of the second flange (21), a pressure relief hole (29) communicated with the top of the cooling cavity (22) and the atmosphere is formed in the second flange (21), and a pressure relief valve (4) is arranged on the pressure relief hole (29). The graphite block (3) is arranged in the cooling cavity (22), and a vertically extending vent