C_5石油树脂合成过程中催化剂脱除方法的研究

对C5石油树脂合成过程中催化剂脱除方法进行了研究.通过对碱洗、水洗、铵洗和醇洗等几种催化剂脱除方法的考察比较,确定最佳脱活剂,并对最佳脱活剂的浓度、用量进行了考察.此外,该文还对复配型的脱活剂进行了探索实验.

Effects of Different Preservative Treatments on Physiological Metabolism and Preservation of Sweet Cherry

[Objective] This study aimed to investigate the effects of different preservative treatments on physiological metabolism and preservation of sweet cherry. [Method] Sweet cherry （Prunus avium var. Summit） was soaked into benziothiazolinone （1 000 ppm）, lysozyme （500 ppm）, lysozyme （500 ppm） ＋ NPS polysaccharide （5 000 ppm） and water for 5 min, respectively. Non-treated sweet cherry was set as control. All the sweet cherries were then put into 3 mm thick PE bags and preserved at （-0.5±0.5） ℃. [Result] The results showed that the malate dehydrogenase （MDH） activity of benziothiazolinone treatment researched a significant peak on the 14 th d, while the MDH activity of Lysozyme （500 ppm）, Lysozyme （500 ppm） ＋ NPS polysaccharide （5 000 ppm） and water treatments began to increase on the 20 th d; the polyphenol oxidase （PPO） activity in various treatments showed a decreasing trend during the experiment, which researched a significant peak on the 14 th d, while that in water treatment was decreased consistently; on the 21 st d, the PPO activity in each treatment increased slowly; the titratable acid （TA） content in preservative treatments was higher than that in both water treatment and control; the soluble solid （SSC） content showed no significant difference between various treatments and between experimental treatment and control; on the 40 th d, the healthy fruit rate in preservative treatments was significantly higher than that in water treatment and control. [Conclusion] Benziothiazolinone, lysozyme and other preservatives show good effects on preservation of sweet cherry; lysozyme treatment can decrease the activity of malate dehydrogenase, maintain the relatively high content of organic acid and significantly improve the healthy fruit rate within a certain period of time.

Research on flue gas desulphurization with two sorbents by water spray in activated reactor

The experimental results of flue gas desulphurization with caustic lime andhydrated lime activated by water spraying in a desulphurization reactor are presented. The effectsof Ca/S molar ratio, approach to saturation of flue gas, SO_2 concentration and gas velocity onsulfur retention efficiency and calcium utilization rate are investigated. Desulphurizationcharacteristics of the two sorbents are compared. The mechanism of improving desulphurizationefficiency by water spraying is analyzed. The results show that the activities of two sorbents areimproved obviously by humidification with water spray and the caustic lime has better applicationprospect because of cheaper cost.

Measurement of Concentration of Sorbent Particles and Water Droplets in Hydration Desulfurization Reactor with PIV

Vortexing limestone injection into furnace combined with calcium lime hydration in the downstream is the most promising technology for controlling SO 2 emission. Particle imaging velocimetry (PIV) is used to measure the gas liquid solid three phase flow field in a reactor. By image processing based on newly developed software, the number concentrations of sorbent particles and water droplets are presented. The measuring results are very helpful for better understanding the desulfurization mechanism and optimizing configurational and operational parameters in the hydration reactor.

Sodium dodecyl sulfate-decorated MOF-derived porous Fe2O3 nanoparticles: High performance, recyclable photocatalysts for fuel denitrification

Magnetically recyclable porous sodium dodecyl sulfate(SDS)/Fe2O3 hybrids,which combine the porous structure of Fe2O3 and hydrophobicity of SDS,have been successfully synthesized for the first time.Porous Fe2O3 has been first pyrolyzed from MIL-100(Fe)using a simple two-step calcination route.Then,the obtained porous Fe2O3 nanoparticles have been self-assembled with SDS molecules and yielded hydrophobic SDS/Fe2O3 hybrids.The porous SDS/Fe2O3 hybrids have been demonstrated to be highly efficient for the denitrification of pyridine under visible light irradiation.The pyridine removal ratio has reached values as high as 100%after irradiation for 240 min.Combining the results of a series of experimental measurements,it was concluded that the superior photocatalytic performance of SDS/Fe2O3 hybrids could be attributed to(i)the fast electron transport owing to the unique porous structure of Fe2O3,(ii)the superior visible light absorption of Fe2O3 nanoparticles,and(iii)the“bridge molecule”role of SDS efficiently improving the separation and transfer across the interfacial domain of SDS/Fe2O3 of photogenerated electron-hole pairs.More significantly,after the catalytic reaction,the SDS/Fe2O3 hybrids could be easily recovered using magnets and reused during subsequent cycles,which indicated their stability and recyclability.

Acid-activated and WO_x-loaded montmorillonite catalysts and their catalytic behaviors in glycerol dehydration

The use of H2SO4‐,HCl‐,H3PO4‐,and CH3COOH‐activated montmorillonite(Mt)and WOx/H3PO4‐activated Mt as catalysts for the gas‐phase dehydration of glycerol was investigated.The WOx/H3PO4‐activated Mt catalysts were prepared by an impregnation method using H3PO4‐activated Mt(Mt‐P)as the support.The catalysts were characterized using powder X‐ray diffraction,Fourier‐transform infrared spectroscopy,N2adsorption‐desorption,diffuse reflectance ultraviolet‐visible spectroscopy,temperature‐programmed desorption of NH3,and thermogravimetric analysis.The acid activation of Mt and WOx loaded on Mt‐P affected the strength and number of acid sites arising from H+exchange,the leaching of octahedral Al3+cations from Mt octahedral sheets,and the types of WOx(2.7≤x≤3)species(i.e.,isolated WO4/WO6‐containing clusters,two‐dimensional[WO6]polytungstates,or three‐dimensional WO3crystals).The strong acid sites were weakened,and the weak and medium acid sites were strengthened when the W loading on Mt‐P was12wt%(12%W/Mt‐P).The12%W/Mt‐P catalyst showed the highest catalytic activity.It gave a glycerol conversion of89.6%and an acrolein selectivity of81.8%at320°C.Coke deposition on the surface of the catalyst led to deactivation.

State-of-the-art catalysts for direct dehydrogenation of propane to propylene

With growing demand for propylene and increasing production of propane from shale gas,the technologies of propylene production,including direct dehydrogenation and oxidative dehydrogenation of propane,have drawn great attention in recent years.In particular,direct dehydrogenation of propane to propylene is regarded as one of the most promising methods of propylene production because it is an on-purpose technique that exclusively yields propylene instead of a mixture of products.In this critical review,we provide the current investigations on the heterogeneous catalysts(such as Pt,CrOx,VOx,GaOx-based catalysts,and nanocarbons)used in the direct dehydrogenation of propane to propylene.A detailed comparison and discussion of the active sites,catalytic mechanisms,influencing factors(such as the structures,dispersions,and reducibilities of the catalysts and promoters),and supports for different types of catalysts is presented.Furthermore,rational designs and preparation of high-performance catalysts for propane dehydrogenation are proposed and discussed.

Influence of Additives on Hydrodesulfurization Activity of Fe-Mo/Al_2O_3 Catalysts

Based on the study relating to the influence of additives on the hydrodesulfurization performance of Fe-Mo-Al2O3 catalysts, it was found out that the introduction of additives could increase considerably the activity of Fe-Mo/Al2O3 catalysts in the reaction of hydrodesulfurization of gasoline and diesel fractions. The introduction of zeolites (HY, HZSM) and other additives could lead to an increase of the concentration of acid centers, which were able to react with sulfur compounds, along with an increase of total catalysts’ pore volume, which could improve the capability of catalyst to adsorb the hydrogen and feed oil.

Study on Relationship between Microstructure of Active Phase and HDS Performance of Sulfided Ni-Mo Catalysts: Effect of Metal Loading

Six Ni-Mo catalysts with different metal contents were prepared and characterized by N2 adsorption and X-ray diffi＇actometry. The active phase microstructure of these catalysts was examined by the Raman spectroscopy, temperature- programmed reduction （TPR）, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. Hydrodesulfurization （HDS） activity of catalyst samples were analyzed in a flow fixed-bed microreactor. The sulfidation degree of Mo and the length of the MoS2 slab slightly increased with the amount of metal loaded following sulfidation. This small change is attributed to polymolybdate species observed in all the oxidized catalysts. Weak metal-support interactions, as determined by the TPR technique, increased the NiSx sulfidation phase and MoS2 slab stacking. The HDS activity of the catalyst samples increased with the number of active sites. For high metal loading catalysts, their HDS activity was nearly identical because the sulfur atoms cannot easily approach active sites. This change is caused by the large number of stacked layers in the MoS2 slabs as well as the decrease in the specific surface area and pore volume of the catalyst samples with an increasing metal loading.

Comparisons between Flotation Deinking Abilities of Newsprint Paper by Using Enzyme and Chemicals

The aim of this research is to study the floatation deinking abilities of black mold enzyme and chemicals in newsprint paper application. In this experiment, the properties of deinked pulp from three different additives--chemicals, black mold enzyme, and chemicals together with black mold enzyme, are studied. The first part of the experiment was to find the optimal amount of chemicals and the optimal pH through the use of sodium hydroxide and surfactant. As a result, 0.2% of sodium hydroxide and 0.4% of surfactant on oven dried weight at pH 9 was found to be the optimal condition for the deinked pulp to yield the lowest ERIC （effective residual concentration） and the highest brightness. The second part of the experiment was to find the optimal amount of black mold enzyme used in the deinking process. As a result, the optimal condition for deinked pulp to retain the lowest ERIC and the highest brightness was 100 ppm of black mold enzyme and 10 minutes of enzyme reaction time. The third part of experiment was to study the de-inking ability of black mold enzyme and chemicals. Consequently, with 30 min of chemicals reaction time and 60 min of black mold reaction time, the deinked pulp retained low ERIC but higher brightness.

Oxidative Desulfurization over Molybdenum-containing MCM-41

Two series of molybdenum-containing MCM-41 catalysts were prepared for oxidative desulfurization ofdibenzothiophene （DBT） using t-butylhydroperoxide （TBHP） as the oxidant. The electronic properties, pore dimension and hydrophilic properties of the catalysts were studied by XRD, BET, and 1R spectrometry. The Mo-Al2O3 catalyst and TiMCM-3% were also studied for comparison. The two series of MCM-41 zeolite with MoO3 in the framework or impregnated on the surface exhibited considerable activities at low MoO3 content and both were faxbetter than the Mo-Al2O3 catalyst, but had lower activities as compared to the TiMCM-3% catalyst. The catalysts with the highest activity were evaluated in a fixed-bed reactor. The concentration of DBT in model diesel upon oxidative desulfurization was successfully reduced from 5000 ppm to less than 150 ppm, but the catalysts were deactivated very fast. The probable reason was the high affinity of DBTO2 to the MCM-41 skeleton, especially to MoO3. The catalysts could restore most of its original activity by treating with alcohol.

Flame Retardancy Evaluation of Nanocomposites Prepared from Sawdust and Montmorillonite Clay

Composites of montmorillonite clay and sawdust were prepared with the desired result being having new materials which burn longer than unmodified sawdust. The three forms of clay used for preparation of composites were unmodified montmorillonite, mono-ionic montmorillonite and organically modified montmorillonite. Montmorillonite clay was converted to mono-ionic clay by ion exchange with sodium using a sodium chloride solution. The mono-ionic clay was organically modified with an organic surfactant, methyl triphenyl phosphonium bromide. Nanocomposites were then prepared by combining the modified and raw forms of the clay with sawdust. The solution blending method was used to make the nanocomposites. The samples were analysed using thermogravimetric analysis and cone calorimetry. The studies showed that the nanocomposite which was made from sawdust and 1% organically modified clay had the most improved results in terms of burning time and thermal stability, as well as giving a calorific value closest to unmodified sawdust and the least amount of residue.

Molecular Simulation Study on Intrinsic Order of Interaction between Single Slab of Active Phase and Al-Si Support in HDS Catalysts

Molecular mechanics and quantum mechanics simulations, as molecular simulation methods, were performed to investigate the effects of different surfaces, the promoter Co/Ni, the active phase of MoS2 or WS2, the content of Si and other factors on the order of interaction between the MoS2 （WS2） single slab and the support surface. The influence of Si content was studied by molecular mechanics, and an advantageous Si content was found. Various surfaces, promoters and active phases also played an important role in the interaction between the support surfaces and active phases, and some significant trends were found out. Quantum mechanics simulation was performed to study the possible effect of electrostatic interaction between the support and the active phase, upon which the calculations suggested that the existence of a favorable Si content was possible. The electronic effects of Co/Ni promoter and the intensity of Co/Mo/Ni/W/Li/AI/Si species bonded to the alumina support were also investigated by quantum mechanics, and it was found that the different electronic effects of Co and Ni might bring forth some obvious influences on the interaction between the support and the active phase. And the results of comparing the intensity of Co/Mo/Ni/W/Li/AI/Si species bonded to the support can also explain the different interaction intensity in various catalyst systems.

Application of Chitosan Flocculant to Conditioning Sludge

The dewaterability of activated sludge conditioned by chitosan flocculant was studied. The effects of chitosan characteristics such as molecular weight, degree of deacetylation, and dose on the dewaterability were investigated. The sludge dewaterability is evaluated in terms of specific resistance to filtration, residual turbidity of supernatant, moisture content of cake, and settling rate. Sludge dehydrating behaviors conditioned with CTS, PAM and PAC flocculants were compared. The conditioning was also carried out with dual flocculants in two stages. It is found that the sludge conditioned with CTS has better dewaterability than that with PAC. The optimum conditions with chitosan are: dose 0.8 - 1.2 g per 100 g dry cake, molecular weight 300,000, and degree of deacetylation 70%. The conditioning in two stages with dual flocculants is found to be more effective than that with single flocculant.

Design of the Metal Precursors Molecular Structures in Impregnating Solutions for Preparation of Efficient Ni Mo/Al_2O_3 Hydrodesulfurization Catalysts

The molecular structures of metal precursors in the impregnating solution were designed so as to prepare efficient Ni Mo/Al_2O_3 hydrodesulfurization(HDS) catalysts. At first, five typical impregnating solutions were designed; the existing metal precursors, such as [Mo4(citrate)2O11]^(4-)-like, [P2Mo18O62]^(6-)-like and [P2Mo5O23]^(6-)-like species in the solutions were confirmed by laser Raman spectroscopy(LRS). The UV-Vis spectra results indicated that the solutions containing both phosphoric acid and citric acid could change the existing form of nickel species. Five corresponding Ni Mo/Al_2O_3 catalysts were prepared by the incipient wetness impregnation method. The LRS analysis results of dried catalysts showed that the above metal precursors could be partly retained on alumina support after impregnation and drying, although the interface reaction between different metal precursors and alumina support unavoidably took place. Then the catalysts were sulfided and characterized by N2 physisorption, TEM and XPS analyses. The results showed that different metal precursors in impregnating solution could mainly result in the difference in both the morphology of(Ni)Mo S2 slabs and the promoting effect of Ni species. The catalyst prepared mainly with [P2Mo5O23]^(6-)-like species used as precursors exhibited worse dispersion of(Ni)Mo S2 slabs and lower ratio of Ni–Mo–S active phases than the one with [Mo4(citrate)2O11]^(4-)-like species. Promisingly, the catalyst prepared with co-existing [Mo4(citrate)2O11]^(4-)-like, [P2Mo18O62]^(6-)-like and [P2Mo5O23]^(6-)-like species showed better hydrodesulfurization activity for 4,6-DMDBT thanks to its more well-dispersed Ni–Mo–S active phases.

Experimental study on removing NO from flue gas using microwave irradiation over activated carbon carried catalyst

Nitrogen oxides(NOx) from flue gas can be removed efficiently by activated carbon continuously irradiated by microwave,which,however,needs high temperature and consumes excessive carbon. If catalyst is added into activated carbon,then reaction temperature can be reduced and selectivity of reaction enhanced. The effects on flue gas denitrification by adding different catalysts to microwave reactor were studied in this paper. It was found that the addition of catalyst could reduce the microwave power required by the same removal efficiency obviously;the difference of removal efficiency was different due to different catalysts,and the Cu-based catalyst has more catalytic action efficiency. Reaction temperature decreased by about 200℃ and removal efficiency increased by 25% after adding Cu-based catalyst. In addition,characteristic analysis for activated carbon conducted by X-ray diffraction confirmed that active component of catalyst existed on the surface of activated carbon.