中低温煤焦油沥青的分离及基础物性研究

Study on separation and basic physical properties of medium-low temperature coal tar pitch

中低温煤焦油沥青由于含有较多的脂肪族烃类物质而导致其在深加工过程中的反应活性不易控制,对中低温煤焦油沥青的分离及基础物性研究可为其高附加值利用提供一定的理论支撑。以中低温煤焦油沥青为原料,将由洗油、煤油和蒽油组成的混合溶剂油作为萃取剂,采用混合溶剂-重力沉降法对中低温煤沥青进行分离,分别得到轻相、重相中低温煤焦油沥青各4种,并利用核磁共振(1 H-NMR)、红外光谱(FTIR)和热重分析(TGA)等技术对分离得到的8种中低温煤焦油沥青的基础物性进行研究。研究结果表明:轻相中低温煤焦油沥青在同种分离条件下的支链化指数均高于重相中低温煤焦油沥青,说明轻相沥青中的支链数量及长度明显低于重相中低温煤焦油沥青;重相中低温煤焦油沥青的软化点、结焦值以及C/H等均高于轻相中低温煤焦油沥青,且重相中低温煤焦油沥青的芳香性要高于轻相中低温煤焦油沥青,即随着混合溶剂油中蒽油添加量的增加,轻/重相中低温煤焦油沥青的芳香缩合度(f_(a))略有增加,但软化点、结焦值明显降低;随着蒽油含量的增加,轻/重相沥青的最大失重速率逐渐减少,通过控制混合溶剂中蒽油的含量可有效调控轻/重相中低温煤焦油沥青的热反应活性。

It is difficult to control the reactivity of medium-low temperature coal tar pitch in deep processing because it contains more aliphatic hydrocarbons.The study on the separation and basic physical properties of medium-low temperature coal tar pitch can provide some theoretical support for its high value-added utilization.Taking medium-low temperature coal tar pitch as raw material,mixed solvent oil consisting of washing oil,kerosene and anthracene oil was used as extraction agent,the mixed solvent and gravity sedimentation method was used to separate medium-low temperature coal tar pitch,and four kinds of light phase and weight phase medium-low temperature coal tar pitch were obtained respectively.Nuclear Magnetic Resonance(1 H-NMR),Infrared Spectroscopy(FTIR)and Thermogravimetric Analysis(TGA)were used to study the basic physical properties of eight kinds of medium-low temperature coal tar pitches.The results show that the branching index results of light phase medium-low temperature coal tar pitch is higher than that of weight phase medium-low temperature coal tar pitch under the same separation conditions,which indicates that the number and length of branched chain in light phase are significantly lower than that of weight phase medium-low temperature coal tar pitch.The SP,CV and C/H of weight phase medium-low temperature coal tar pitch are higher than the light phase,and the aromaticity of weight phase medium-low temperature coal tar pitch is higher than the light phase.With the increase of addition of anthracene oil in the mixed solvent oil,the aromatic condensation(f_(a))of the medium-low temperature coal tar pitch in the light/weight phase increases slightly,but the SP and CV decreases obviously.In addition,with the increase of anthracene oil content,the maximum weight loss rate of light/weight phase pitch decreases gradually.In other words,the thermal reactivity of medium-low temperature coal tar pitch in light/weight phase can be effectively regulated by controlling the content of anthracene oil in the mixed solvent.