Abstract: An excess heat recovery apparatus and process for high temperature chlorine dioxide bleaching of pulp is provided. The pulp of the high temperature chlorine dioxide bleaching stage enters a tube-side of a chlorine dioxide preheater through a pipeline. The low-temperature chlorine dioxide in the storage tank enters a shell-side pipeline of the chlorine dioxide preheater. 0.5 mol/L of a stabilizer may be added during preheating to prevent ClO2 from decomposing during the heating process. Preheated chlorine dioxide is then moved into a pulp mixer and the pH is adjusted to 3.2-3.8. The mixed pulp is then moved into a high temperature chlorine dioxide bleaching tower for bleaching. The cooling pulp, now out of the preheater, is washed in an alkaline extraction stage. The waste water from the washing flows directly into an effluent treatment system and is recycled after treatment.

Abstract: A system for the integral chlorine dioxide production with relatively independent sodium chlorate electrolytic production and chlorine dioxide production is provided. The system may feed electrolyte solution into a solid-liquid filter, filtering out the crystal and eliminating sodium chloride and sodium dichromate. The sodium chlorate crystal may be fed into a chlorine dioxide generator after dissolving, while sodium chloride and sodium dichromate solution separately return to electrolyzer for electrolysis process. Sodium chloride may be constantly formed as a by-product in the chlorine dioxide production unit, and solution containing the sodium chloride is withdrawn from the generator and, after filtration, washing and dissolution, recycled back to sodium chlorate production unit. This way, there is no need of sodium chloride make-up.