催化裂化油浆固含量测定及组成分析

Determination and composition analysis of solid contents in FCC slurry oil

采用灰分法、过滤法、离心法测量了某重油催化裂化装置外甩油浆的固体颗粒含量,对几种方法在固含量测定方面的结果差异进行对比分析。实验结果表明,离心法测量的固含量约为2850μg/g,介于灰分法和过滤法之间。离心法结果显示,油浆中重组分与细粉颗粒存在较强的吸附作用,分离中能否准确得到焦粉是造成结果差异的主要原因。离心法耦合后续焙烧能够分离获得油浆中一定量的催化剂细粉颗粒,通过激光粒度仪、元素分析仪、XRD、BET、SEM-EDS等手段对分离得到的固体颗粒以及初始FCC催化剂进行了表征。FCC催化剂粒径集中在32~120μm之间,为规则的球形分布,油浆中的固体颗粒呈不规则的块状分布,粒径在0.4~40μm之间,其中催化剂细粉的粒径在1~30μm之间;催化裂化油浆中的固体颗粒组成主要有催化剂细粉、焦粉和碱金属K、Ca、无机盐和金属元素Sb、Fe等。

Ash analysis, filtration and centrifugation analysis were adopted to measure the content of solid particles in the FCC slurry oil from a residue fluid catalytic cracking (RFCC) unit in CNPC. The solid content measured by centrifugation method was about 2850μg/g, which was between those by the ash analysis and filtration methods. The centrifugation method results indicated that the strong adsorption between fine particles and the heavy components in the slurry oil was the key factor to obtain coke powder. Centrifugal method coupled with subsequent calcination could isolate and obtain certain amount of solid particles from the slurry oil. Then the solid particles and the original FCC catalyst were characterized by means of laser particle size analyzer, elemental analyzer, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy & energy spectrum analysis (SEM-EDS), etc. The fresh FCC catalyst was regular spherical and showed a size distribution in the range of 32-120μm, while the solid particles in the oil slurry were scattered and irregular with the particle size of 0.4-40μm, in which the fine catalysts were mostly between 1-30μm. The solid particles in FCC slurry oil mainly consisted of catalyst powder, coke powder, inorganic metal salts, such as alkali metal (K, Ca), antimony (Sb), and iron (Fe).