Reuse of residue hydrodesulfurization catalyst is very important, as a large volume of this catalyst is exchanged every year due to the high deactivation rate. However, stable regeneration of this catalyst is more difficult than for distillate HDS catalysts due to the more severe regeneration conditions and the presence of vanadium. Regeneration technologies of residue hydrodesulfurization catalyst are reviewed to assess the differences between regeneration of distillate HDS catalysts, mechanism of residue HDS catalyst regeneration, commercial regeneration, properties, structure, and activities of regenerated residue HDS catalyst, effect of vanadium and improvement of catalyst suitable for regeneration. The presence of vanadium accelerates both insufficient recovery of activity and reduced catalyst strength due to formation of NiMoO4 and Al2(SO4)3, respectively. However, removal of vanadium might be not essential. Vanadium acts indirectly as oxidative catalyst and increases the regeneration temperature and transformation of SOx into H2SO4. Therefore, milder regenerated conditions and control of the properties of used catalyst as well as improvement of catalyst may allow improved regeneration.
Solid-state metal oxides with three-dimensional organization of catalytic components at nano-scale have high potential as catalysts for chemical conversion because the materials could provide unique reaction fields at catalytic active sites which are particularly important for multi-step catalytic reactions like selective oxidation. Here, crystalline Mo3VOx, a new type complex metal oxide catalyst, is introduced as a prominent example of solid-state metal oxides with three-dimensional organization. The material has a network arrangement of pentagonal units as a structure building block with the formation of 6-member ring channel and 7-member ring channel in its crystal structure. The material showed an outstanding catalytic performance for both selective oxidations of ethane to ethene and of acrolein to acrylic acid, revealing the importance of these structures for the catalytic oxidation activity. The outstanding catalytic performance for the reactions is ascribed to octahedra clusters isolated in the pentagonal unit network and to microporous property of the 7-member ring channel.
Hydrogenation of dimethyl adipate (DMA) to 1,6-hexanediol (1,6-HDO) was studied on supported noble metal-Sn binary catalysts at 300 °C and 9.1 MPa of H2 in an autoclave. Binary catalysts were prepared by the conventional impregnation method and characterized by XRD, TPR and XPS. Among the catalysts studied, Rh–Sn supported on α-Al2O3 gave the highest 1,6-HDO yield. A novel reaction scheme is proposed including 6-hydroxyhexyl methyl adipate produced by an ester-exchange reaction between DMA and 1,6-HDO. The molar ratio of Sn to Rh greatly affected the catalytic performance. The active site structure and valences of Rh and Sn are discussed. Comparison of the catalytic performance with reported catalysts suggested that Rh–Sn and previous Ru–Sn catalysts provided superior selectivity for 1,6-HDO to previous Cu–Cr catalyst at the same DMA conversion.
A fundamental chemical enhanced oil recovery (EOR) process is surfactant flooding in which the key mechanism is to reduce interfacial tension between oil and the displacing fluid and hence mobilizing the trapped oil. Surfactant loss by adsorption is one of the most important criteria that governs the economics of the surfactant flooding methods. In addition to this, detrimental effects and high price of currently used surfactants cause EOR process so expensive and unfeasible. This study is aimed to introduce a novel kind of plant based surfactant which is extracted from Zizyphus Spina-Christi tree. In addition, equilibrium adsorption behavior of this novel biosurfactant in aqueous solution on crushed reservoir rocks is presented. A conductivity technique was used to assess the critical micelle concentration (CMC) value in the aqueous phase. Batch experiments were used to understand the effect of adsorbent dose on sorption efficiency as well. Four adsorption models were also employed to make a quantitative description of equilibrium adsorption behavior of surfactant solution. For evaluating the ability of this novel biosurfactant on the surface properties, IFT values of Saponin solution were compared to those of commonly used chemical surfactants in petroleum industry. It is shown that availability and the low cost of the Zizyphus Spina-Christi extract in comparison to common chemical surfactants in petroleum industry make it economically viable for surfactant flooding.
Production of bioethanol by the conversion of lignocellulosic material such as rice straw, based on enzyme hydrolysis and yeast fermentation has attracted much interest in recent years. Furthermore, the on-site production of cellulase enzyme is an important strategy for the development of commercial ethanol production. The cost-effectiveness analysis of bioethanol production from rice straw was analyzed in various scenarios of on-site cellulase enzyme production and cellulase enzyme purchase, assuming 15 JPY/kg rice straw cost and 15,000 kL/year facility size. Bioethanol production cost by on-site cellulase enzyme production was estimated at 177 JPY/L-ethanol. The equivalent enzyme cost suitable for the same ethanol production cost was 938 JPY/106 FPU. The analysis showed that decreasing aeration from 1.0 to 0.5 VVM reduced the cost of bioethanol production to 171 JPY/L-ethanol and increasing cellulase productivity from 10.5 FPU/100 mg rice straw to 21.0 FPU/100 mg rice straw reduced the cost of bioethanol production to 147 JPY/L-ethanol. Therefore, bioethanol production cost was greatly affected by the enzyme productivity.
Low temperature partial oxidation of methane to produce syngas was investigated over Ni catalysts supported on various perovskite oxides. Pre-reduced Ni catalyst supported on LaAlO3 perovskite showed high catalytic activity at 673 K, the lowest temperature reported to date. Ni particles on LaAlO3 perovskite showed weaker interaction between metal and support, and were reduced at lower temperature than on other Ni catalysts. Partial oxidation proceeded via methane combustion and steam reforming, and the reduced Ni particles were active sites for both of these reactions. Additional impregnation of Pd enabled catalysis of the reaction without pre-reduction. The functions of Ni particles, LaAlO3 perovskite, and supported Pd were investigated by various methods, and found that Pd promoted the oxidation of methane, and catalytic partial oxidation proceeded over reduced Ni.
Hydrogenation of 4-t-butylphenol over an activated carbon-supported rhodium catalyst in carbon dioxide solvent was analyzed based on phase observation with a view cell and calculations of the solubility of 4-t-butylphenol using the Peng-Robinson equation of state as a function of carbon dioxide pressure. The reaction experiments showed that the initial reaction rate of 4-t-butylphenol at 313 K under 2 MPa of hydrogen pressure was increased by the addition of carbon dioxide, especially above a total pressure of 11 MPa. Direct visual observation showed that the solubility of 4-t-butylphenol increased with higher carbon dioxide pressure. The calculations based on the Peng-Robinson equation of state also showed that the solubility of 4-t-butylphenol in the 4-t-butylphenol–carbon dioxide–hydrogen (2 MPa) system at 313 K significantly increased by addition of carbon dioxide above a total pressure of 11 MPa. We concluded that the increase in the hydrogenation rates was caused by the increased concentration of 4-t-butylphenol substrate in the carbon dioxide solvent.
A bioethanol certified reference material (CRM), NMIJ CRM 8301-a, has been issued by the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ, AIST). The raw material for this CRM is fermented bioethanol made from rice. Certified values have been provided for the contents of water, methanol, sulfur and copper. This CRM can be used for calibration and validation of water, methanol, sulfur and copper analysis in bioethanol fuel and similar matrices. This paper describes the methods for the determination of the certified value of sulfur for CRM 8301-a. The certified value was determined by analysis of the sample candidate reference material subdivided in ampoules. The measurement of sulfur in the candidate reference material was performed using combustion ultraviolet fluorescence detection and combustion ion chromatography detection. The certified sulfur value is 2.43 mg kg −1 and the expanded uncertainty (k = 2) is 0.23 mg kg −1.
To recognize the conditions of soil contamination by oil, to know the concentration of contaminants in the soil is necessary. Total Petroleum Hydrocarbons (TPH) is commonly used to assess oil contaminated soil. TPH measurement methods in the laboratory usually adopt solvent extraction of the hydrocarbon from the soil prior to gas chromatography (GC) or infrared (IR) analysis. In order to increase the laboratory efficiency and reduce the cost of soil contamination investigations, some screening analysis methods are used. In this study, in order to develop a screening analysis for oil contaminated soil, a method to determine TPH values by measuring CO2 concentrations of burning gas from soil sample was investigated and established as TPH analyzer.