Brown Coal Tar Preparation Of Organic Bases - Petroleum Phenolic Wastewater Phenol Removal By Extractant

Phenols are organic pollutants of high priority concerns because of their toxicity and possible accumulation in the environment.But they are also the mainly materials in organic chemical industry.Therefore,it is very important to reduce and reclaim phenols from wastewater economically and effectively.Complexation extraction method is used to remove phenols from wastewater in this paper.A new type of extraction agent----coal tar(170℃～230℃),which comes from lignite gasification process in Jiehua Chem Group Co.,Ltd,is developed.The concentration of phenols is about 30%～36%in the coal tar,and there is a large amount of pyridines which can form complexant with phenols.In this thesis,pyridines is joined into coal tar treated by NaOH and H₂SO₄,then forms as pyridines-coal tar complexation extraction system which is used to remove phenols from wastewater,and try to ascertain the best technical condition of extraction and reverse extraction process.Reclaim phenols after alkali washing process,and distill the organic alkali compounds from acid residues decomposed by ammonia.The results show that,treated coal tar washed by 20%NaOH under the volume proportion of 1:1 and then washed by 92%H₂SO₄ under the volume proportion of 1:5,have many advantages than the original coal tar.The concentration of phenols is less than 5%, most of the colloids and asphaltum have been wiped off,and the density and viscosity is lower.The treated coal tar is more stabilization,as well as less impurity,higher diaphaneity and smell better.In the distillation experiment,the organic alkali compounds is finded between the temperature of 110℃～130℃and 130℃～180℃.The dependence of extraction efficiency on the component of extraction agents,pH, phase ratio R(extractant/aqueous),reaction temperature,time and rotor speed was investigated in the singularity factor extraction experiment.And the mutual-factors experimental results show that,when the proportion of pyridines to the treated coal tar is 6%,pH=7,R=1.4:1,reaction temperature is 50℃,rotor speed is 160 r/min and reaction time for about 5 min,the removal efficiency of phenols will be up to 90%,and the concentration of phenols will drop to 300mg/L.The extraction efficiency balance curve proved that pyridines-coal tar complexation extraction system is good at the wastewater treatment containing high concentration phenols.In the extractant regeneration experiment,15%NaOH is used to reverse extract the phenols from coal tar.The best technical condition of reverse extraction process is that phase ratio being 1:1.5(alkali/coal tar),reaction temperature being 55℃,rotor speed being 140 r/min and reaction time being about 3 min,the reverse extraction efficiency will be more than 99.5%.It is also sufficed to the industry need.