نتایج جستجو برای: spent catalysts
تعداد نتایج: 68511 فیلتر نتایج به سال:
The physical and chemical properties of raw bio-oil, two oxidized bio-oils, and hydrotreated bio-oil were compared before and after catalytic hydrodeoxygenation using sulfided CoMo/γ-Al2O3 catalyst. Following continuous hydrodeoxygenation, the organic liquid products from treated bio-oils and raw bio-oil were compared for higher heating value, oxygen content, water content, and viscosity. In ad...
Introduction Industrially condensation reactions are of great importance in the production of a number of key compounds. These include 2-ethyl hexanol, methyl isobutyl ketone (MIBK) and Guerbet alcohols. Over 1.5 million tonnes of these chemicals are produced worldwide every year using homogeneous bases such as NaOH and Ca(OH)2. It has been estimated for these compounds that 30% of the selling ...
The physical and chemical properties of tungsten oxide supported on SBA-15 mesoporous silica prepared by a controlled grafting process through atomic layer deposition (ALD) were studied using complementary characterization methods. X-ray diffraction, optical absorption, and transmission electron microscopy showed that tungsten oxide species are highly dispersed on SBA-15 surfaces, even at 30 wt...
Currently, the Brown-Schlesinger process is still regarded as the most common and mature method for the commercial production of sodium borohydride (NaBH4). However, the metallic sodium, currently produced from the electrolysis of molten NaCl that is mass-produced by evaporation of seawater or brine, is probably the most costly raw material. Recently, several reports have demonstrated the feasi...
Feasibility Assessment on Remanufacturing of Ni–Mo/?–Al2O3 Catalyst for Residue Hydrodesulfurization
Residue hydrodesulfurization (RHDS) is a critical process in the petroleum refining industry for removing sulfur compounds from heavy residual oils. However, catalysts used RHDS can easily be deactivated by numerous factors, leading to reduced efficiency and economic benefits. The remanufacturing of spent useful strategy extending lifespan catalysts, reducing waste, improving sustainability. Th...
BACKGROUND To our knowledge, research has not been conducted on bicycle riding and weight control in comparison with walking. Our objective was to assess the association between bicycle riding and weight control in premenopausal women. METHODS This was a 16-year follow-up study of 18,414 women in the Nurses' Health Study II. Weight change between 1989 and 2005 was the primary outcome, and the...
The purpose of this study was to quantify and contrast the instantaneous segmental and total body energy patterns of rowing a single scull racing shell with rowing a Gjessing (Norway) rowing ergometer (RE), and to contrast energy savings through exchanges of mechanical energy among segments and conversions of energy within segments. Four scullers, two male and two female, were filmed at three s...
Electrical and electronics equipment and automotive and industrial catalysts are some examples of top technological devices whose functioning rely on the use of platinum-group metals (PGMs). The PGMs’ high economic value and difficult to replace technological properties, together with their scarcity in the Earth’s crust, justify concerns about their critical condition and reinforce the importan...
In this study, the recovery of platinum and palladium from petroleum catalysts has been elaborated using a method consisting mainly of dissolving alumina substrate in sulfuric acid thereby concentrating the precious metals in the residue. The effect of dissolution temperature and time, concentration of sulfuric acid, and pulp density on the dissolution of alumina substrate was investigated syst...
Abstract Spent vanadium catalysts of sulfuric acid production (main elemental composition in wt%: 7.5 V, 9.1 K, 10.2 S, 23.2 Si and 1.4 Fe) can be used as a secondary source vanadium. Extraction was studied using two-step leaching (acidic reductive) spent with further oxidizing solutions. The factors hydrolysis temperature, concentration (H2SO4, Na2SO3) ((NH4)2S2O8) reagents, solid/liquid ratio...
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