| The white pine resources of northeast of China are rich，and the annual output of solidfuels made by white pine sawdust is up to about150000t. Tar originated from preparationprogress of forming carbon is up to50000t/a. But the effectively utilized way of tar has notbeen found so far. It not only causes waste of resources but also affects the environment.Therefore, how to promote the utilization of tar becomes a social research focus. Theperformance and composition of the pyrolysis tar of white pine molding fuel have been studiedin this paper, and explore a feasible technology of chemical application. The main researchcontents and results are as follows:1) Performance analysis The pyrolysis tar performance was detected. The resultindicated tar had high content of water and oxygen, low content of nitrogen and sulfur, and lowvalue of calorific. Tar density was similar to water density. The tar was strong corrosive for itshigh acid value. Tar viscosity decreased with the increasing of temperature. Carbonyl, hydroxyland aromatic groups were detected in tar by infrared spectral. TGA were studied in differentatmosphere. The result indicated that at room temperature stored length had little effect forchemical composition of tar, the pyrolytic rate of tar increased at150℃and reached themaximum at200℃. Meanwhile it was more than a burning stage in air atmosphere comparedwith nitrogen atmosphere of the tar. Under nitrogen atmosphere, the tar pyrolysis behavior wasinvestigated with different heating rates of5,10,20,30K/min, it was divided into two steps.The kinetic method of Coats-Redfern was used to analyze the TG data to identify reactionparameters which reflcet reaction mechanis. And the results showed the reaction could be welldescribed by first reaction order and two stages model. Forty-one compounds were separatedand identified from pyrolysis tar by GC-MS analysis, the relative quality masse of phenoliccompounds was39.21%.2) Atmospheric distillation6kinds of fractions were separated by distillation, there arerespectively under110℃、110～140℃、140～160℃、160～190℃、190～220℃and220℃～ 240℃. The result indicated when heating up more than240℃, tar became black asphalt, thefractions have accounted for almost46.72%of the tar, and the rate of distillation was fast at110℃and210℃. The acid value of fractions between110℃to160℃was highest, and theviscosity greatly improved at220℃. It was found that guaiacol and its homologue are existedas azeotrope by analysis components and kinetic analysis of various fractions, their relativequality masse was over29.37%.3) Synthesis of phenol-formaldehyde resin (PF) adhesive The32compounds weredetermined by GC/MS, the relative content of phenolic compounds was up to79.57%.Synthesis technique of PF adhesive was studied by one-step reaction and sample temperatureprogramme catalyzed by NaOH. The best synthesis condition was determined by orthogonalexperiment with regard to the amount of wood tar substituted, reaction time and reactiontemperature. The results showed that the content of wood tar substituted is20%, reactiontime is2.5h and reaction temperature is85℃. The content of wood tar substituted isremarkable in these factors, it was found that with the increasing of the content of wood tarsubstituted, free phenol content gradually decreased and free formaldehyde content increased,and viscosity also increased. Viscosity increased sharply when the content is more than25%.4) Extraction of phenols Phenolic compounds were further separated from thefraction(170~220℃)by liquid-liquid extraction using alkali and organic solvents. Componentsand contents of the compounds were analyzed byGC-MS. Experiment results showed that afterextraction, the relative quality masses of small molecules such as acids, aldehydes andpolycyclic aromatic hydrocarbons were decreased to30%，and the compounds mainlyconsisted2-methoxy-4-methylphenol, guaiacol and4-ethylguaiacol. Their relative qualitymasses were19.61%,17.95%and11.14%, respectively. |
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