National Institute of Standards and Technology における超伝導研究及び生活

An overview of new approaches to deep desulfurization for ultra-clean gasoline, diesel fuel and jet fuel

Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40th anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are dee...

Fundamentals and Catalytic Applications of CeO2-Based Materials

It is well known that urbanization and industrialization have resulted in the rapidly increasing emissions of volatile organic compounds (VOCs), which are a major contributor to the formation of secondary pollutants (e.g., tropospheric ozone, PAN (peroxyacetyl nitrate), and secondary organic aerosols) and photochemical smog. The emission of these pollutants has led to a large decline in air quality in numerous regions around the world, which has ultimately led to concerns regarding their impact on human health and general well-being. Catalytic oxidation is regarded as one of the most promising strategies for VOC removal from industrial waste streams. This Review systematically documents the progresses and developments made in the understanding and design of heterogeneous catalysts for VOC oxidation over the past two decades. It addresses in detail how catalytic performance is often drastically affected by the pollutant sources and reaction conditions. It also highlights the primary routes for catalyst deactivation and discusses protocols for their subsequent reactivation. Kinetic models and proposed oxidation mechanisms for representative VOCs are also provided. Typical catalytic reactors and oxidizers for industrial VOC destruction are further discussed. We believe that this Review will provide a great foundation and reference point for future design and development in this field.

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Recent Advances in the Catalytic Oxidation of Volatile Organic Compounds: A Review Based on Pollutant Sorts and Sources.

This paper is a selective review on design approaches and associated catalysis and chemistry for deep desulfurization and deep dearomatization (hydrogenation) of hydrocarbon fuels, particularly diesel fuels. The challenge for deep desulfurization of diesel fuels is the difficulty of removing the refractory sulfur compounds, particularly 4,6-dimethyldibenzothiophene, with conventional hydrodesulfurization processes. The problem is exacerbated by the inhibiting effect of polyaromatics and nitrogen compounds, which exist in some diesel blend stocks on deep HDS. With the new Environmental Protection Agency (EPA) Tier II regulations to cut the diesel sulfur from current 500 ppmw down to 15 ppmw by June 2006, refineries are facing major challenges to meet the fuel sulfur specification along with the required reduction of aromatics contents. The principles and problems for the existing hydrodesulfurization processes, and the concepts, advantages and disadvantages of various new approaches will be discussed. Specifically, the following new design approaches for sulfur removal will be discussed: (1) novel catalysts for ultra-deep hydrodesulfurization under conventional HDS process conditions; (2) new design concept for sulfur-tolerant noble metal catalysts for low-temperature hydrogenation; (3) new desulfurization process by sulfur adsorption and capture under H2; (4) new desulfurization process by selective adsorption at ambient temperature without H2 and a related integrated process concept; (5) oxidative desulfurization in liquid-phase; and (6) biodesulfurization.

New design approaches to ultra-clean diesel fuels by deep desulfurization and deep dearomatization

Deoxygenation of vegetable oils has a potential to become an important process for production of biofuels. The present work focuses on investigation of Ni, Mo, and NiMo sulfided catalysts prepared by impregnation in deoxygenation of rapeseed oil at 260–280 °C, 3.5 MPa and 0.25–4 h −1 in a fixed-bed reactor. The activity of the catalysts decreased in the order NiMo/Al 2 O 3  > Mo/Al 2 O 3  > Ni/Al 2 O 3 . The catalysts exhibited significantly different product distributions. The bimetallic NiMo catalysts showed higher yields of hydrocarbons than the monometallic catalysts at a given conversion. Apart from the various oxygenated product intermediates, NiMo/Al 2 O 3 yielded a mixture of decarboxylation and hydrodeoxygenation hydrocarbon products while Ni/Al 2 O 3 yielded only decarboxylation hydrocarbon products and Mo/Al 2 O 3 yielded almost exclusively hydrodeoxygenation hydrocarbon products. The effect of Ni/(Ni + Mo) atomic ratio in the range 0.2–0.4 on the activity and selectivity was not significant.

Deoxygenation of vegetable oils over sulfided Ni, Mo and NiMo catalysts

The Co, Mo and CoMo catalysts in different Co/Mo ratios supported on SiO2, ZrO2, TiO2, Al2O3, active carbon and MgO were prepared. The catalysts were tested in the hydrodesulphurisation of benzothiophene. The order of activity of monometallic Mo catalysts was MoO3/TiO2 > MoO3/C > MoO3/ZrO2 > MoO3/SiO2 > MoO3/Al2O3 > MoO3/MgO. The order of promotion of MoO3/support by Co addition was CoMo/MgO > CoMo/C > CoMo/Al2O3 > CoMo/TiO2 > CoMo/ZrO2 > CoMo/SiO2. The synergism in activity was accompanied with a decrease of hydrogenation/hydrogenolysis selectivity. Hydrogenolysis was promoted more than hydrogenation and thus less dihydrobenzothiophene was formed on CoMo than on Co and Mo catalysts. The TPR patterns were measured, and the degree of reduction correlated with the activity of monometallic catalysts. The TPR patterns of CoMo catalysts were similar to the patterns of Mo catalysts, and no correlation with magnitude of promotion was found.

Effect of support type on the magnitude of synergism and promotion in CoMo sulphide hydrodesulphurisation catalyst

High activity of highly loaded MoS2 hydrodesulfurization catalysts supported on organised mesoporous alumina

Carbon-supported Mo catalysts prepared by a new impregnation method using a MoO3/water slurry: saturated loading, hydrodesulfurization activity and promotion by Co

Luděk Kaluža

Papers

Deoxygenation of vegetable oils over sulfided Ni, Mo and NiMo catalysts

Effect of support type on the magnitude of synergism and promotion in CoMo sulphide hydrodesulphurisation catalyst

High activity of highly loaded MoS2 hydrodesulfurization catalysts supported on organised mesoporous alumina

Carbon-supported Mo catalysts prepared by a new impregnation method using a MoO3/water slurry: saturated loading, hydrodesulfurization activity and promotion by Co

Performance of platinum and gold catalysts supported on ceria-zirconia mixed oxide in the oxidation of chlorobenzene