Chlor-alkali system for ultraviolet photolysis of nitrogen trichloride and operation method of chlor-alkali system

According to the chlor-alkali system, two ultraviolet photolysis reactors are arranged on a chlorine gas pipeline in front of a compressor behind a chlorine gas drying tower in parallel, and the characteristic that nitrogen trichloride can be decomposed when meeting light is utilized; and the nitrogen trichloride in the chlorine is decomposed by an ultraviolet photolysis method in cooperation with an auxiliary part. The equipment investment cost is low, the nitrogen trichloride removal rate is high, and the operation method is simple, safe and effective. The controller adjusts and controls the operation number of the ultraviolet lamp tubes so as to control the content of nitrogen trichloride; one ultraviolet photolysis reactor is used and the other ultraviolet photolysis reactor is standby, so that maintenance is convenient, and front and rear stop valves are convenient to isolate from the system during maintenance; the splitter plate ensures that chlorine is uniformly distributed in the reactor; replacement