Effect of Preparation Methods and Content of Boron on Hydrotreating Catalytic Activity

Abstract

The effects of boron content and preparation methods are studied in this present investigation. Three different methods are employed for the preparation of catalysts. The catalysts are characterized by pore size distribution (PSD), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Thiophene hydrodesulfurization (HDS), cumene hydrocracking (HC), gas oil HDS and Maya heavy crude oil HDS, and hydrodemetallization (HDM) activities are tested. The results show that the specific surface area and PSD are not changed with B loading. The enrichment of metal distribution on the alumina surface is observed from SEM experiments for the 0.6B–NiMo catalyst. More staging of MoS2 active phases is noticed in the B catalyst than the B-free catalyst. It can be stated that boron forms a monolayer on the alumina surface and reduces the metal–support interaction. It facilitates the formation of more staging of active phases. The thiophene HDS activity slightly increases with boron loading up to 0.6 wt % B, and after that, the activity becomes constant or slightly decreases. The cumene cracking of the NiMo–B catalyst shows the highest activity. The overall activity of boron catalysts was found to be the same or marginally higher than that of the boron-free catalyst. The presence of boron may help to reduce catalyst deactivation during hydrotreating of heavy crude oil.

Advancement of Hydro-Desulfurization Catalyst and Discussion of Its Application in Coal Tar

“…The modulation capability of promoters for catalyst performances is not only relevant to the nature of the promoter itself and quantity of the promoter, but also connected with the impregnation order of active metal and the promoter [18,19,22,50,51] …”

“…To these promoters, The content must be suitable because excessive content of promoter may inversely strengthen the metal-support interaction due to the improvement of the dispersion degree of active phase in this case [50]; third, promoters could achieve the modulation ability through "isolation" of the active metal and support in physical space. For B modified catalyst B-MoNi/ Al 2 O 3 and MoNi-B/Al 2 O 3 [22], the former which impregnated B and MoNi in sequence has better modulation capability than the latter. This is because B (w0.6%) could be monolayer distribution on the carrier surface in B-MoNi/Al 2 O 3 , which "separates" active metal and carrier in some extent and thereby weaken the metal-carrier interaction.…”

“…For B-MoNi/Al 2 O 3 [22], W-Ni 2 P/SBA-15 [15], Mo-Ni 2 P/SBA-15/cordierite [16], when B (w) of 0.8%, W (w) 3%, Mo (w) 4.2%, their specific surface area and pore volume are maximal, respectively. Such effect of B, W and Mo can be attributed to the impact of promoter content on the dispersion state of active metal.…”

“…Promoter is an important part of the catalyst and a lot of confidential materials are concentrated in it. It is essential to optimize its kinds and content in the process of catalyst preparation [13][14][15][16][17][18][19][20][21][22]. The available carriers in HDS catalyst are as the following types ac-cording to the chemical compositions: silicon-aluminum molecular sieves [23,24], metallic oxides [25,26], mesoporous silica molecular sieves [10,11,27,28] and composites made up by these materials [7,8,23,26].…”

Effect of Catalyst Deactivation on the Energy Consumption of Gasoline–Diesel Hydrotreating Process

“…Researchers also did a lot of studying on the hydrotreating reactors. Maity et al studied the effects of boron content and preparation methods, and found that the presence of boron may help to reduce catalyst deactivation during hydrotreating of heavy oil. Maritnez and Ancheyta studied the kinetics of parallel thermal and catalytic hydrotreating reactions, and identified that the reactions occur via a catalytic route at low severity reaction conditions, while thermal reactions are more favored at high severity conditions.…”