Claydon Ryan, Wood Joseph
School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, U.K.
Energy Fuels. 2019 Nov 21;33(11):10820-10832. doi: 10.1021/acs.energyfuels.9b02735. Epub 2019 Oct 21.
Heavy oil contains a significantly lower H/C ratio and higher quantity of organic heteroatoms and organo-metallic complexes than conventional light oil. Consequently, novel catalytic materials are needed to aid in heavy oil upgrading to remove the deleterious components and support the higher demand for low sulfur and higher value fuels. Heavy oil upgrading was studied using an inexpensive nickel-aluminum Layered Double Hydroxide (LDH)-derived Ni-enriched Mixed Metal Oxides (Ni-MMO) dispersed catalyst in a Baskerville autoclave. The conditions were set at 425 °C, initial pressure of 20 bar, 0.02 Catalyst-To-Oil (CTO) ratio, and a residence time of 30 min to mimick previously optimized conditions for in situ upgrading processes. The extent of the upgrading following catalytic pyrolysis was evaluated in terms of a solid, liquid, and gaseous phase mass balance, liquid viscosity reduction, desulphurization, and True Boiling Point (TBP) distribution. A typical in situ activated CoMo-alumina commercial hydroprocessing catalyst was used as a reference. It was found that the produced oil from dispersed ultrafine Ni-MMO exhibited superior light oil characteristics. The viscosity decreased from 811 to 0.2 mPa·s while the light naptha fraction increased from 12.6% of the feed to 39.6%, with respect to the feed. Using a thorough suite of analytical techniques on the petroleum coke product, including Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM), a reaction mechanism has been hypothesized for the upgrading by dispersed Ni-MMO under both N and H atmospheres. Under a N atmosphere, the Ni-MMO, generated by the in situ thermal decomposition of the LDH, demonstrate a preferential asphaltene and poly aromatic adsorption mechanism, generating a poly aromatic mixed oxide-coke precursor. While using Ni-enriched mixed oxides under a reducing H atmosphere, hydrogenation reactions become more significant.
与传统轻质油相比，重油的氢碳比显著更低，有机杂原子和有机金属络合物的含量更高。因此，需要新型催化材料来助力重油升级，以去除有害成分，并满足对低硫和高价值燃料的更高需求。在巴斯克维尔高压釜中，使用一种由廉价的镍铝层状双氢氧化物（LDH）衍生的富含镍的混合金属氧化物（Ni-MMO）分散催化剂对重油升级进行了研究。条件设定为425℃、初始压力20巴、催化剂与油的比例（CTO）为0.02，以及停留时间30分钟，以模拟先前原位升级过程的优化条件。通过固相、液相和气相质量平衡、液体粘度降低、脱硫以及实沸点（TBP）分布来评估催化热解后的升级程度。使用一种典型的原位活化CoMo-氧化铝商业加氢处理催化剂作为参考。结果发现，由分散的超细Ni-MMO生产的油表现出优异的轻质油特性。粘度从811降至0.2 mPa·s，而轻质石脑油馏分相对于进料从进料的12.6%增加到39.6%。通过对石油焦产物使用一系列全面的分析技术，包括热重分析（TGA）和扫描电子显微镜（SEM），已经推测出在氮气和氢气气氛下分散的Ni-MMO进行升级的反应机理。在氮气气氛下，由LDH原位热分解生成的Ni-MMO表现出优先的沥青质和多环芳烃吸附机制，生成多环芳烃混合氧化物-焦炭前驱体。而在还原性氢气气氛下使用富含镍的混合氧化物时，氢化反应变得更加显著。
