Integration of wastewater treatment units and optimization of waste residue pyrolysis conditions in the brominated phenol flame retardant industry.

[Display omitted] • An efficient production process of TBBPA has been developed by regulating the process parameters. • A high-value process of waste water/residues in the TBBPA production process was proposed. • Water and chlorobenzene can be recovered and reused through cleverly designing wastewater. • The pyrolysis removes organic impurities in waste residue while obtaining Na 2 SO 4 products. Among the bromine flame retardants, tetrabromobisphenol A (TBBPA) is a highly effective flame retardant that can be used as both reactive and additive. However, the synthesis reaction of TBBPA has a low conversion rate and many brominated phenolic organics. Therefore, there is an urgent need to remove brominated organic pollutants produced in the process of producing flame retardants to reduce the harm to the environment and human beings and to reduce production costs. In this study, an efficient process was developed to treat the wastewater and waste residue generated in TBBPA production process, realizing its harmless and resource utilization. In the resource utilization system, through the ingenious design of solution mixing, precipitation separation, three-effect evaporation and concentration, valuable substances were extracted to realize the recovery and reuse of wastewater. In the harmless utilization process of hazardous waste residue, through high-temperature pyrolysis at 500 °C for 2 h after optimization with hypoxia-hyperoxia atmosphere modulation, it can avoid the production of dioxins and carbon black, effectively remove the organic impurities, realize the harmlessness and obtain high-quality sodium sulfate. This paper aims to propose a simple, efficient and feasible utilization system, including the three major technological processes of TBBPA production, integrated wastewater treatment and optimized the harmless treatment of waste residue to obtain sodium sulfate, so as to realize TBBPA green production. Compared with the traditional TBBPA synthesis system, wastewater and waste residue treatment processes, the TBBPA quality is increased by 2 % and the economic cost is reduced by 10 %, which is of great significance to the development of the industry. [ABSTRACT FROM AUTHOR]