煤基粗油轻质组分定性定量分析现状与展望

Status quo and outlook of qualitative and quantitative analysis of light weight fractions of coal-based crude oil

煤基粗油是指原煤经各种热化学反应、化工过程加工处理后得到的初级液体产物,包括煤焦油、煤直接液化油和煤间接液化油等。以生产过程全流程物料衡算为约束条件,对煤基粗油全组分组成的准确定性定量分析,不仅可以全面掌握煤基粗油的组成组分性质,而且可实现对煤基粗油的进一步精准加工、提质生产。但由于煤基粗油组分组成的复杂性,不仅难以实现进样组分及分析结果之间的物料衡算,而且也不能最大程度地实现对所有组分的组成及含量的准确分析,至今尚未见到对此内容相关文献资料报道,也没有相应分析方法的国家或行业标准。因此,以物料衡算为约束,建立全面、系统的分析方法,对煤基粗油进行精准定性定量分析是目前亟需解决的问题。本文指出利用气相色谱与红外光谱联用、液相色谱分离后与紫外光谱、同步荧光光谱联用等光谱分析法可快速获得煤基粗油族组分含量的测定,或是对煤基粗油性质做定性的描述;核磁共振波谱法可实现酚类化合物准确的定性、定量;化学分析法仅适合于煤基粗油具体成分的定性定量分析;红外光谱、核磁共振波谱、凝胶渗透色谱和元素分析结合可系统分析与表征煤基粗油及其组分,得到一些重要的物质结构参数信息;色谱分析法可通过色谱的分离功能使复杂混合物分离,并利用各种检测器工作原理的不同来实现定性和定量。其中定性主要采用质谱仪、光谱仪、核磁共振波谱仪等;定量的方法有归一化法、内标法、外标法、响应因子预测法。针对煤基粗油轻质组分(沸点<350℃)组成的定性定量,气相色谱-质谱联用(GC-MS)技术为此分析过程提供了可能,本文提出并推导了火焰离子化检测仪(FID)响应因子预测公式,将该公式与面积归一化法联用建立FID定量方法体系,加标回收实验(回收率为99.07%,质量分数)表明该方法体系准确、有效,可以被广泛应用于复杂有机混合物的定量分析中,并指出煤基粗油轻质组分定性定量分析过程中的关键在于对复杂混合物中各组分响应因子的准确获得。

Coal-based crude oil refers to initial liquid products obtained from thermal chemical reactions,chemical engineering processes of coal,which includes coal tar,coal direct liquefaction oil,and Fischer-Tropsch oil etc.Accurately analyzing the chemical composition and characteristics of coal-based crude oil is beneficial to its fine processing,downstream industrial processing and conversion of the objective products with a product-demand-oriented mode.At the same time,an intensive study of the composition of coal-based crude oil also contributes to the improvement of coal processing techniques.However,due to the complexity of coal-based crude oil,no exact composition and content of coal-based crude oil have been reported,and there is no national or industry standard for corresponding analysis methods so far.Particularly the problem of material balance during the whole production process in the qualitative and quantitative analysis has not been solved yet.Therefore,a more precise qualitative and quantitative analysis of coal-based crude oil with material balance as a constraint,and the establishment of a comprehensive and systematic analysis method in the whole production process is still an urgent issue to be solved.The paper points out that the combination of gas chromatography and infrared spectroscopy,liquid chromatography separation and ultraviolet spectroscopy,synchronous fluorescence spectroscopy,and other spectral analysis methods can quickly obtain the content of coal-based crude oil groupcomponents,or qualitative description of coal-based crude oil properties;Nuclear magnetic resonance spectroscopy can achieve accurate qualitative and quantitative determination of phenolic compounds;Chemical analysis is only suitable for qualitative and quantitative analysis of specific components of coalbased crude oil;Analysis and characterization combination of infrared spectroscopy,nuclear magnetic resonance spectroscopy,gel permeation chromatography and elemental analysis can systemically acquire some important structural parameters of coal-based crude oil;Chromatographic analysis can separate complex mixtures by chromatographic separation function,and use different detectors to achieve qualitative and quantitative of samples.The qualitative methods mainly use mass spectrometer,spectrometer,nuclear magnetic resonance spectrometer,etc.The quantitative methods include normalization method,internal standard method,external standard method and response factor prediction method.For the qualitative and quantitative determination of the light weight fractions of coal-based crude oil(boiling point<350℃),gas chromatography-mass spectrometry(GC-MS)technology provides the possibility of this analysis process.Especially the detection principle and quantitative method of flame ionization detector(FID)detector was reviewed at length and deduced the FID response factor prediction formula.The formula will be combined with area normalization method to establish the FID quantitative method system,and results from the standard addition recovery experiment(recovery rate is 99.07 wt%)indicate that the method system is accurate and effective,and can be widely applied to the quantitative analysis of complex organic mixtures.In the end,the key to the material balance in the whole production process lies in the prompt,accurate and large-scale quantification of complex organic compounds was pointed out.Preliminary analysis results showed that the combination of instruments,especially GC-MS/FID,would be one of the main ways to achieve qualitative and quantitative analysis of composition of light weight fractions constrained by material balance for the time being.It was inferred that the key to the qualitative and quantitative analysis of the light components of coal-based crude oil was the accurate acquisition of the response factors of each component in the complex mixture.