Purification and reuse of carbon black wastewater of acetylene production from natural gas by microchannel filtration

Abstract

Carbon black wastewater is a by-product of partial oxidation of natural gas to acetylene and can cause serious pollution to the environment. In this study, the effect of deep bed filtration (microchannel filtration) in the synergistic separation of particulate pollutants and organic pollutants in carbon black wastewater were investigated. The results indicated that the separation efficiency of carbon black particles with a mean diameter of 6.88 µm was 95%− 98%, 95–97%, and 95%− 96% when the filter material was quartz sand + quartz sand, quartz sand + activated, and quartz sand + anthracite, respectively. The solid content of inlet was 300 mg/L and 145 NTU, respectively, and those of the purified effluent were below 15 mg/L and 14 NTU, which meet the first-class B standard of China sewage discharge. The total kinds of organics were reduced from 29 to 2. The separation efficiency of C6-C24 all higher than 97%. A 150 m3/h full-closed treatment process for carbon black wastewater was designed to replace the original open sedimentation tank. The carbon black wastewater could be efficiently purified by this method, the purified carbon black wastewater could be reused, and the carbon black was used to make a filter cake for recycling in rubber without discharge. Finally, the possibility of achieving zero discharge of carbon black wastewater is shown.