Integrated treatment processes for coal-gasification wastewater with high concentration of phenol and ammonia

Abstract

Wastewater from pressurized fixed bed coal gasification has been all along regarded as one of the most difficult water to treat. It contains high concentration of phenols and ammonia. The most efficient treatment method is distillation and extraction. Phenols and ammonia are recovered as products. However, energy consumption, in the form of low-pressure steam and mid-pressure steam, is relatively high. Energy consumption of the wastewater treatment process developed by South China University of Technology is analyzed in this paper. Two integration processes based on SCUT wastewater treatment process are proposed in which solvent recovery system is thermally integrated. The results indicate that these integrations decrease energy consumption by about 18% compared to the conventional SCUT process. The cost of wastewater treatment can reduce to 0.2 CNY/ton of wastewater. The competitiveness of the technology for wastewater treatment is improved.