Study On The Separation And Utilization Of The Coal-based Liquid Production

Properties of low-temperature coal tars derived from pyrolysis by the different pyrolytic process were characterized, the 120～320℃fraction was separated into basic compounds, acidic compounds and neutral compounds by NaOH extraction, the main components in the acidic compounds and neutral compounds were determined by GC-MS. The results showed that the two tars contains hardly any basic compounds, the major components of acidic fraction are phenols, High-value- phenols such as methyl-phenol and dimethylphenol make up about thirty to forty-five percent of all phenols, saturated and aromatic hydrocarbon were rich in the neutral compounds, dimethyl naphthalene takes up a great proportion of sixteen percent in aromatic hydrocarbon, there are some differences in properties between the different low-temperature coal tars.Phenols in the fraction were separated by solvent extraction by single factor parallel experimental method, The correlation between the alkaline wash conditions and the yield of phenol was reaserched:NaOH concentrations> extraction temperature> solvent burden ratio >static placing time. Cross and repeated test routed out the optimum extraction conditions: NaOH concentrations 15%, extraction temperature 50℃, static placing time 120 min, solvent burden ratio1/3, H2SO4 concentrations 40%, the yield of phenol 47.25%, the recovery of phenol can reach to 95.01%.Thermal polymerization modification of coal tar pitch was studied in the 400ml reactive kettle, the effects of polymerizing temperature and retention on modified pitch were examined. The study showed the key parameters of coal tar pitch have a regular increased with the increasing temperature and holding time.When the coal tar pitch reaction 30min at the temperature of 375℃, the TI, QI, SP, CV andβpeucine can reached 32%,9.01%,106.3℃, 59.10% and 23.6% respectively. The reaserch found that there is a good linear relationship between CV, SP, TI and QI:QI,TI,SP= kCV+A. In the hot filtration experiment,50% of the QI could be removed and the recovery of coal tar approximately 85% when filtered with the 1000 filter cloth at the temperature of 60℃, the results demonstrated that hot filtration have a good effect on removal of QI in the coal tars.