Removal Of Tar From Coke Oven Gas By Emulsion Liquid Membrane

Tar contains a variety of heterocyclic aromatic hydrocarbons,polycyclic aromatic hydrocarbons,benzene series and other harmful substances,many of which are carcinogens.If the coke oven flue gas containing tar is directly discharged into the atmosphere,it will not only pollute the environment,but also endanger people's health.The emulsion liquid membrane separation technology has the advantages of high mass transfer efficiency,the membrane phase can be recycled and there is no secondary pollution,etc.The technology has been widely used in wastewater treatment,drug extraction and metal ion recovery and other fields.Emulsion liquid membrane technique(ELM)was used to remove tar from flue gas.W/O/W emulsion was prepared with Span-80 or L-113 B as surfactant,kerosene as membrane solvent,distilled water as internal phase and external phase.Operating conditions such as the concentration of surfactant,the volume ratio of oil phase to internal phase,the volume ratio of emulsion to external phase,and emulsification speed were optimized.The experimental results shown that when Span-80 was used as the surfactant,the tar removal efficiency up to 93.89%;When L-113 B was used as the surfactant,the tar removal efficiency up to 98.21%.The separation of loaded emulsion was carried out by centrifugation method.The results showed that the demulsification efficiency was 69.14% when L-113 B was used as the surfactant at the centrifugal speed was 7000 r/min and the centrifugation time was 21 min.Under the same conditions,the demulsification efficiency was 68.38% when Span-80 was used as the surfactant.The recycling effect of the membrane phase and the unbroken emulsion was not significantly lower than that of the fresh emulsion.In the study of simultaneously removal of tar and dust by emulsion liquid membrane method,the removal efficiency of tar and dust were 98.32% and 96.37% respectively under the optimal operating conditions.Figure 44;Table 10;Reference 70.