Djokic Marko R, Ristic Nenad D, Olahova Natalia, Marin Guy B, Van Geem Kevin M
Laboratory for Chemical Technology, Ghent University, Technologiepark 914, 9052 Ghent, Belgium.
J Chromatogr A. 2017 Aug 4;1509:102-113. doi: 10.1016/j.chroma.2017.06.006. Epub 2017 Jun 2.
An improved method for on-line measurement of sulfur containing compounds in complex matrices is presented. The on-line system consists of a specifically designed sampling system connected to a comprehensive two-dimensional gas chromatograph (GC×GC) equipped with two capillary columns (Rtx-1 PONA×SGE BPX50), a flame ionization detector (FID) and a sulfur chemiluminescence detector (SCD). The result is an unprecedented sensitivity down to ppm level (1 ppm-w) for various sulfur containing compounds in very complex hydrocarbon matrices. In addition to the GC×GC-SCD, the low molecular weight sulfur containing compounds such as hydrogen sulfide (HS) and carbonyl sulfide (COS) can be analyzed using a thermal conductivity detector of a so-called refinery gas analyzer (RGA). The methodology was extensively tested on a continuous flow pilot plant for steam cracking, in which quantification of sulfur containing compounds in the reactor effluent was carried out using 3-chlorothiophene as internal standard. The GC×GC-FID/-SCD settings were optimized for ppm analysis of sulfur compounds in olefin-rich (ethylene- and propylene-rich) hydrocarbon matrices produced by steam cracking of petroleum feedstocks. Besides that is primarily used for analysis of the hydrocarbon matrix, FID of the GC×GC-FID/-SCD set-up serves to double check the amount of added sulfur internal standard which is crucial for a proper quantification of sulfur compounds. When vacuum gas oil containing 780 ppm-w of elemental sulfur in the form of benzothiophenes and dibenzothiophenes is subjected to steam cracking, the sulfur balance was closed, with 75% of the sulfur contained in the feed is converted to hydrogen sulfide, 13% to alkyl homologues of thiophene while the remaining 12% is present in the form of alkyl homologues of benzothiophenes. The methodology can be applied for many other conversion processes which use sulfur containing feeds such as hydrocracking, catalytic cracking, kerogen evolution, bio-waste pyrolysis, supercritical water treatment, etc.
本文提出了一种用于在线测量复杂基质中含硫化合物的改进方法。该在线系统由一个专门设计的采样系统组成，该采样系统连接到一台配备两根毛细管柱（Rtx - 1 PONA×SGE BPX50）、一个火焰离子化检测器（FID）和一个硫化学发光检测器（SCD）的全二维气相色谱仪（GC×GC）。对于非常复杂的烃类基质中的各种含硫化合物，该系统可实现低至ppm水平（1 ppm - w）的前所未有的灵敏度。除了GC×GC - SCD外，还可以使用所谓的炼厂气分析仪（RGA）的热导检测器来分析低分子量含硫化合物，如硫化氢（HS）和羰基硫（COS）。该方法在蒸汽裂解连续流中试装置上进行了广泛测试，其中以3 - 氯噻吩作为内标对反应器流出物中的含硫化合物进行定量分析。GC×GC - FID / - SCD设置针对石油原料蒸汽裂解产生的富含烯烃（富含乙烯和丙烯）的烃类基质中硫化合物的ppm分析进行了优化。除了主要用于分析烃类基质外，GC×GC - FID / - SCD装置的FID还用于双重检查添加的硫内标的量，这对于含硫化合物的准确定量至关重要。当含有780 ppm - w以苯并噻吩和二苯并噻吩形式存在的元素硫的减压瓦斯油进行蒸汽裂解时，硫平衡是封闭的，进料中75%的硫转化为硫化氢，13%转化为噻吩的烷基同系物，而其余12%以苯并噻吩的烷基同系物形式存在。该方法可应用于许多其他使用含硫进料的转化过程，如加氢裂化、催化裂化、干酪根演化、生物废物热解、超临界水处理等。
