Desulfurization of gasoline by condensation of thiophenes with formaldehyde in a biphasic system using aqueous phase of acids

Aqueous phase of acids as catalysts for the desulfurization of gasoline by condensation of thiophenes with formaldehyde in a biphasic system was investigated. Two types of model gasoline with and without aromatics and olefins were employed in this work. The desulfurization rates were above 90% on these two types of model gasoline using formic acid and H_3PW_(12)O_(40)(0.8 mol·L~(-1)), indicating that the presence of aromatics and olefins has no effect on the desulfurization rate. High temperature(above 90 °C) was more favorable to the process for desulfurization. Four hours was considered to be the proper treating time for the sulfur removal. In addition,aqueous phase of acids could be recycled at least 4 times without decreasing desulfurization rate. Finally, the possible process for the integration of condensation desulfurization into the existing refinery process for the production of gasoline with low sulfur content was proposed.     

Changes in char reactivity due to char-oxygen and char-steam reactions using Victorian brown coal in a fixed-bed reactor

This study was to examine the influence of reactions of char–O2 and char–steam on the char reactivity evolution. A newly-designed fixed-bed reactor was used to conduct gasification experiments using Victorian brown coal at 800 °C. The chars prepared from the gasification experiments were then collected and subjected to reactivity characterisation (ex-situ reactivity) using TGA (thermogravimetric analyser) in air. The results indicate that the char reactivity from TGA was generally high when the char experienced intensive gasification reactions in 0.3%O2 in the fixed-bed reactor. The addition of steam into the gasification not only enhanced the char conversion sig-nificantly but also reduced the char reactivity dramatical y. The curve shapes of the char reactivity with involve-ment of steam were very different from that with O2 gasification, implying the importance of gasifying agents to char properties.     

有机溶剂原位萃取法提高悬浮培养中国红豆杉细胞紫杉醇产量

The production of paclitaxel from suspension culture of Taxus chinensis var,mairei was improved by in situ extraction with organic solvents to avoid feedback repression and product degradation.Oleic acid and dibutyl phthalate were proved to be suitable solvents .The optimal volumetric percentage of organic solvents in the culture medium was found to be around 8%,and the favorable time for their introduction was at the exponential phase of cell growth,Paclitaxel production with the in situ extraction was ca 3-fold of that without extraction.     

乙烯分子在狭缝炭孔内的毛细相变和自扩散

The grand canonical Monte Carlo (GCMC), the canonical Monte Carlo by using equal probability perturbation, and the molecular dynamics (MD) methods were used to study the capillary phase-transition (capillary condensation and evaporation) and self-diffusion for a simple Lennard-Jones model of ethylene confined in slit carbon pores of 2.109 nm at temperatures between 141.26 K and 201.80 K. The critical point of capillary phase-transition was extrapolated by the critical power law and the law of rectilinear diameter from the capillary phase-transition data in the near critical region. The effects of temperature and fluid density on the parallel self-diffusion coefficients of ethylene molecules confined in the slit carbon pores were examined. The results showed that the parallel selfdiffusion coefficients in the capillary phase transition area strongly depended on the fluids local densities in the slit carbon pores.     

加压下规整填料塔内气液两相轴向返混实验研究

An experimental study of the extent of axial backmixing in both gas and liquid phases was conducted in a 150 mm ID column packed with Mellapak 250Y corrugated structured packing. The column was operated at pressures ranging from 0.3 MPa to 2.0MPa with nitrogen and water flowing countercurrently through the packing. The amount of axial backmixing was experimentally evaluated by the pulse response techniques using hydrogen in gas phase and an aqueous solution of NaCl in liquid phase as inert tracers. The response of the tracer was monitored by means of thermal conductivity in the gas phase and electrical conductance in the liquid phase. The experimentally determined residence time distribution (RTD) curves were interpreted in terms of the diffusion-type modei. The results indicated that the axial backmixing in the gas increased notably with gas flowrate and slightly with operating pressure and liquid flowrate. The liquid-phase axial backmixing was an increasing function of both gas and liquid flowrates an     

Density,refractive index and liquid–liquid equilibrium data of polyethylene glycol 3000 + potassium formate + water at different pH values

New liquid–liquid equilibrium data for polyethylene glycol(PEG) 3000 + CHO_2K + H_2O systems were measured at 298.15 K and pH values of 7.95, 8.40 and 9.98. It was found that an increase in pH caused the binodal curve to be displaced downward and the two-phase region to expand. Accordingly, the binodal curve was adjusted to the Pirdashti equation and the tie-line compositions were correlated using the Othmer–Tobias, Bancroft and Hand equations. The study measured the refractive index and densities of several homogeneous binary and ternary solutions. The solutions were used for calibration within a range of 0% to 30% of the mass of the PEG and potassium formate. The density and refractive index data show a linear variation with the mass fraction of the polymer and the salt. The effect of pH on the binodal, tie-line lengths(TLL) and slope of the tie-line(STL) in the systems was examined. It was found that an increase in pH increased the TLL and decreased the STL. It was observed that the density of the aqueous two-phase system was influenced by the TLL. The difference in density between phases(Δρ) increased as the TLL and pH increased. It was found that the TLL and Δρ showed a linear relationship. The effective excluded volume(EEV) of the PEG was obtained and it was found that EEV also increased as the pH increased.     

自养型生物过滤器硝化氧化一氧化氮

Carbon foam-a, kind of new engineering material as packing material was adopted in three biofilters with different pore dimensions and adapted autotrophic nitrite nitrobacteria to investigate the purification of nitric oxide (NO) in a gas stream. The biofilm was developed on the surface of carbon foams using nitrite as its only nitric source. The moisture in the filter was maintained by ultrasonic aerosol equipment which can minimize the thickness of the liquid film. The liquid phase nitrification test was conducted to determine the variability and the potential of performance among the three carbon foam biofilters. The investigation showed that during the NO2--N inlet concentration of 200g·L-1-min-1 to 800g·L-1-min-1, the 24PPC (pores per centimeter) carbon foam biofilter had the greatest potential, achieving the NO--N removal efficiency of 94% to 98%. The 8PPC and 18PPC carbon foam biofilters achieved the NO2--N removal efficiency of 15% to 21% and of 30% to 40%, respectively. The potential for this     

Effect of La_2O_3 Addition on Hydration Properties of CaO Clinker

To obtain CaO clinker with high density,low porosity,and good hydration resistance,the effect of the La_-2O_3 content on physical properties,such as sintering property and hydration resistance of CaO clinker was researched in this paper. Apparent porosity and bulk density were measured by Archimedes principle with kerosene as the medium. Two methods were used to test hydration resistance of CaO clinker. One was carried out in a humidity cabinet at 20 ℃ with 90% of relative humidity.Another was the boiling method. SEM and EDS characterization analyses of CaO clinker were performed to observe the microstructural information and the hydration mechanism was put forward. The results show that:(1)the specimen with 0. 79 mass% of La_2O_3 addition has lower apparent porosity,and higher bulk density;(2)the hydration mass gain of CaO clinker with 0.79 mass% La_2O_3 addition is lower,which is less than 1% after 20 days;(3) La_2O_3 mainly distributes in the grain boundary,and a small amount of La_2O_3 dissolves in grains. The average grain size of CaO specimens with 0.79 mass% La_2O_3 addition sintered at 1450℃,1550℃,and 1650℃,is 44.5 μm,48.6 μm,and 63.5 μm,respectively;(4) solid solution is formed due to the similar ionic radius of La~(3+)and Ca~(2+),which promotes the sintering of CaO clinker and improves the hydration resistance simultaneously.     

聚合物涂层竖板上水蒸气滴状冷凝传热特性的研究

The plasma polymerization method and dynamic ion-beam mixed implantation method were employed to coat ultra-thin polymer films on copper plates. Experiments indicated that steady dropwise condensation of steam at atmospheric pressure occurred. The condensation heat transfer coefficients increased by approximately 3 and 5---7 times for the polytrimethylvinylsilane film and polytetrafiuoroethylene film respectively, compaxed with the value for film condensation under the same experimental conditions. The temperatures on the condensing surface and inside the test block were found to be rapidly and randomly fluctuated. The properties of the coated films and advantages of the methods used in this investigation were discussed briefly.     

Comparison of steam-gasification characteristics of coal char and petroleum coke char in drop tube furnace

The steam-gasification reaction characteristics of coal and petroleum coke (PC) were studied in the drop tube fur-nace (DTF). The effects of various factors such as types of carbonaceous material, gasification temperature (1100–1400 °C) and mass ratio of steam to char (0.4:1, 0.6:1 and 1:1 separately) on gasification gas or solid products were investigated. The results showed that for al carbonaceous materials studied, H2 content exhibited the larg-est part of gasification gaseous products and CH4 had the smal est part. For the two petroleum cokes, CO2 content was higher than CO, which was similar to Zun-yi char. When the steam/char ratio was constant, the carbon con-version of both Shen-fu and PC chars increased with increasing temperature. When the gasification temperature was constant, the carbon conversions of al char samples increased with increasing steam/char ratio. For al the steam/char ratios, compared to water gas shift reaction, char-H2O and char-CO2 reaction were further from the thermodynamic equilibrium due to a much lower char gasification rate than that of water gas shift reaction rate. Therefore, kinetic effects may play a more important role in a char gasification step than thermodynamic ef-fects when the gasification reaction of char was held in DTF. The calculating method for the equilibrium shift in this study wil be a worth reference for analysis of the gaseous components in industrial gasifier. The reactivity of residual cokes decreased and the crystal layer (L002/d002) numbers of residual cokes increased with increasing gasification temperature. Therefore, L002/d002, the carbon crystallite structure parameter, can be used to evaluate the reactivity of residual cokes.     

三聚氰胺氰尿酸盐阻燃聚氨酯硬泡

将三聚氰胺氰尿酸盐(MCA)作为阻燃剂,采用一步全水发泡法,制备一系列硬质聚氨酯泡沫/三聚氰胺氰尿酸盐复合材料(RPUF/MCA),采用扫描电子显微镜(SEM)、热重分析(TG)、极限氧指数(LOI)、UL-94垂直燃烧、烟密度测试、傅立叶红外光谱(FT-IR)及拉曼光谱表征,研究了MCA对硬质聚氨酯泡沫(RPUF)泡孔结构、热稳定性、阻燃性及燃烧烟气密度的影响。研究表明,MCA能够显著提高RPUF/MCA的阻燃性能,30份的MCA使RPUF/MCA30达到UL-94 V-1级别,极限氧指数达到22.0%。热重测试结果表明,MCA的添加使成炭率降低;同时发现,MCA的添加降低了RPUF/MCA泡沫复合材料的初始热分解温度和复合材料的燃烧烟气密度,有效地提高了复合材料火灾安全性能。     

氧化亚酮和三氧化钼对PVC阻燃和抑烟作用

用锥形量热仪（CONE）研究Cu2O/MoO3体系对PVC的阻燃和抑烟协同效应可以同时获得气相和凝聚相的综合信息。实验结果表明：Cu2O/MoO3对PVC的总热释放量（THR），表现出了一定的协同阻燃作用，其原因是Cu2O/MoO3改变了PVC的热解途径，协同降低了PVC炭骨架的热裂解速度，增加了残余炭的生成量。综合分析可知，Cu2O/MoO3对PVC的阻燃协同作用有现在凝聚相中，抑烟协同作用同时表现在凝聚相和气相中。     

Mechanism of smoke suppression by melamine in rigid polyurethane foam

The smoke suppression of rigid polyurethane foam (RPUF) modified by melamine was investigated based on three sections: the condensed phase, the carbon layer, and the gas phase. In the condensed phase, the results of thermogravimetry, X‐ray photoelectron spectroscopy (XPS) N1S spectrum, and Fourier transform infrared spectroscopy indicated that melamine could suppress the degradation of RPUF by reacting with the aromatic hydrocarbons. It also reduced the smoke generation because the volatilizable aromatic hydrocarbons were the principal smoke precursors in a fire. In the carbon layer, the decrease from 38.50% to 24.76% of the inner layer oxygen content identified by XPS full‐spectrum and C1S spectrum indicated that melamine could prevent oxygen from transferring into the inner foam by the formation of an enhanced surface carbon layer, and the enhanced carbon layer could also block the release of smoke precursors. In the gas phase, the content of total aromatic hydrocarbons declined to 59.12% according to pyrolysis gaseous chromatography mass spectroscopy and indicated that melamine could reduce the smoke precursors. The results of smoke density chamber and cone calorimeter tests revealed that the addition of the melamine could decrease the smoke density of burning RPUF. Copyright © 2014 John Wiley & Sons, Ltd.     

Flame retardation and thermal stability of novel phosphoramide/expandable graphite in rigid polyurethane foam

A novel flame retardant named diethylene N,N',N''‐tri (diethoxy)phosphoramide (DTP) was synthesized using diethyl phosphate and diethylenetriamine via Atherton–Todd reaction. Then, series of flame‐retardant water‐blown rigid polyurethane foams (RPUFs) with expandable graphite (EG) and DTP were prepared through box‐foaming. The results of thermogravimetric analysis showed that DTP/EG changed thermal degradation process of RPUF and promoted enhancing char residues. The complex flame‐retardant system (EG/DTP) endowed RPUF higher limiting oxygen index (LOI) values (29.1%–30.2%) and lower heat release rate peak (PHRR) values according to LOI and microscale combustion calorimeter tests. More importantly, the synergistic flame‐retardant effect between EG and DTP in RPUF was proved by the analysis of synergistic effectivity values. Based on the analysis of cone calorimetric tests, EG/DTP revealed remarkable effects to inhibit the fire intensity and smoke release of RPUF with decreased PHRR and total smoke production due to good char‐forming action. To further investigate the char‐residues of the foams after combustion, scanning electron microscope and energy dispersive X‐ray spectroscopy analyses were conducted. The results suggested that EG/DTP flame‐retardant system promoted RPUF forming a compact, continuous and phosphorus‐rich char layer as a good fire barrier in combustion. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46434.     

Inorganic/organic phosphorus-based flame retardants synergistic flame retardant rigid polyurethane foam

The flame-retardant rigid polyurethane foam (RPUF) composites are fabricated by ammonium polyphosphate (APP) with pentaerythritol phosphate (PEPA), phenoxycycloposphazene (PCP), and aluminum diethylphosphinate (ADP), respectively, which are labeled as RPUF-1, RPUF-2, and RPUF-3. The influence of flame retardants on the apparent density and compressive strength of RPUF is studied. The results reveal that flame retardants not only improve the apparent density, but also improve the compressive strength of RPUF composites. The limiting oxygen index (LOI) results reveal that these inorganic/organic phosphorus-based flame retardants improve the LOI significantly, especially for RPUF-2 and RPUF-3 systems. The cone calorimeter test results suggest that the peak of heat release of RPUF-1, RPUF-2, and RPUF-3 systems decrease by 38%, 41%, and 52% likened to that of pure RPUF. And APP and ADP system performs best in declining the heat release. And APP and PEPA systems perform best in decreasing the smoke release. The flame retardancy mechanism of RPUF composites is analyzed in details.     

Enhanced Flame Retardancy of Rigid Polyurethane Foams by Polyacrylamide/MXene Hydrogel Nanocomposite Coating

Rigid polyurethane foam (RPUF) has been widely used in many fields, but its high flammability and frequent release of large amounts of toxic smoke during combustion limit its application. Hydrogel coatings, as a kind of environmentally friendly material, contain large amounts of water, which is beneficial to flame retardance of RPUF. MXene, as a two-dimensional inorganic nanomaterial, possesses a large specific surface area and good thermal stability, performing well in smoke suppression and as a physical barrier for flammable gas products and heat. Herein, to address the fire hazards of RPUF, MXene nanosheets were first grafted with double bonds, and then introduced into a polyacrylamide hydrogel system by radical polymerization to prepare MXene-based hydrogel coating (PAAm-MXene). The flame-retardant RPUF (coated RPUF) was prepared by painting the PAAm-MXene coating onto RPUF surface. The dispersion of modified MXene nanosheets (m-MXene) in hydrogels is improved compared with pristine MXene, and the addition of m-MXene contributes to the thermal stability enhancement of PAAm-MXene. Cone calorimetry, water retention test, and open flame combustion test were used to study the flame retardancy, smoke suppression, and water retention of flame-retardant RPUF. The coated RPUF exhibited significant flame retardancy, including reduced peak heat release rate (pHRR) at a maximum by 25.8%, and total heat release rate (THR) at a maximum by 24.6%, and total smoke production at a maximum by 38.9%. The results show that both MXene and m-MXene can improve the flame retardancy, smoke suppression, and water retention of hydrogels, but m-MXene has a better smoke suppression effect than MXene. That can be ascribed to the better dispersion of m-MXene than pristine MXene. The detailed performance improvement mechanisms are proposed. This work will not only improve the flame retardancy of RPUF, but also promotes the exploration of new flame-retardant strategies for RPUF.     

Zn2SnO4的制备及其对软质聚氯乙烯的阻燃研究

以结晶四氯化锡和硝酸锌为原料,通过2步煅烧法制备锡酸锌(Zn2SnO4)阻燃剂;通过极限氧指数、烟密度等级和残炭量研究了Zn2SnO4对软质聚氯乙烯（PVC）的阻燃和消烟性能的影响,同时对力学性能进行了研究。结果表明,Zn2SnO4的用量为15份时,对软质PVC的阻燃消烟效果明显,其极限氧指数可达36.0 %、烟密度等级为86.2 %、残炭率为29.7 %、拉伸强度为25.47 MPa、断裂伸长率为168 %;利用热重分析、差热分析和扫描电子显微镜等方法对阻燃PVC进一步进行表征,结果表明Zn2SnO4的加入促使软质PVC的起始分解温度降低,残炭量增加,燃烧后剩炭结构致密,阻燃效果明显。     

四元复合体系在硬质聚氨酯泡沫材料中的逐级释放阻燃行为研究

以甲基膦酸二甲酯（DMMP）、10-（2,5-二羟基甲苯）-10-氢-9-氧杂-10-磷酰杂菲-10-氧化物（DOPO-HQ）、可膨胀石墨（EG）和氢氧化铝（ATH）构建了四元阻燃复合体系,并通过热失重分析仪（TG）、锥形量热仪、极限氧指数分析仪等研究了其在硬质聚氨酯泡沫（RPUF）中的阻燃行为。结果表明,四元阻燃体系能够在较宽温度区间内发挥逐级释放的协同阻燃效应;DOPO-HQ能够与EG/DMMP/ATH三元阻燃体系形成加合阻燃效应,使得RPUF复合材料的极限氧指数（LOI）提升至30.8%;与采用EG/DMMP/ATH三元阻燃体系的RPUF复合材料相比,采用加入DOPO-HQ的四元阻燃体系的RPUF复合材料的热释放速率峰值（PHRR）、总热释放量（THR）、总烟释放量（TSR）均有所下降,残炭率得到了进一步提升,说明DOPO-HQ与EG/DMMP/ATH所构建的四元阻燃体系在成炭性方面具有协同效应;此外,通过扫描电子显微镜（SEM）对残炭进行表征,验证了四元阻燃体系在凝聚相中能够发挥优异的成炭阻隔效应,并能够在燃烧的初期、中期和末期发挥逐级释放阻燃效应。     

Highly efficient fire retardant behavior,thermal stability,and physicomechanical properties of rigid polyurethane foam based on recycled poly(ethylene terephthalate)

This study focused on the burning phenomena, thermal stability, and physicomechanical properties of polyurethane foam based on recycled poly(ethylene terephthalate) (RPUF) with and without halogen-free flame retardants (FRs). Flammability behavior and associated mechanisms were studied by cone calorimetry, LOI, UL 94, FTIR, TGA, FE-SEM, and XPS. The results of cone calorimeter testing indicate improved FR performance with notable reductions in peak heat release rate (~39.1%), peak CO production (~61.7%), and peak CO₂ production (~43.0%). LOI values significantly increase, up to 29.5–47.1%, in the presence of FRs, and V-0 ratings are attained even at a rather low loading of FR (6.07 wt%). Meanwhile, the RPUF completely burns to the holder clamp with a low LOI value (17%), and it do not pass the UL94 HB standard. The addition of FRs notably improves the residual char of RPUF, indicating that FRs contributed to the formation of a barrier layer to protect RPUF during degradation. The comparison between experimentally determined TGA results and calculated values provides support for the effect of FRs on the thermal degradation behavior of RPUF. Sorption isotherm experiments of RPUF/FR systems show low moisture absorptivity and a weak hysteresis effect due to strong intermolecular bonds between RPUF and added FRs. The compression test, density, and morphology of foam samples are also discussed.     

Reactivity of the raw materials and their effects on the structure and properties of rigid polyurethane foams

Formulations for rigid polyurethane foams (RPUFs) based on crude 4,4′‐diphenylmethane diisocyanate, polyether polyol, triethylenediamine, 1,4‐butane diol, poly(siloxane ether), methylene chloride, and water were studied. The stoichiometric ratios of various foam ingredients and their effects on physical properties such as the cream time, gel time, tack‐free time, and density of the RPUF samples were studied. The results indicated that the rate of RPUF formation increased with the catalyst (triethylenediamine and tin) and water content. The density of the RPUF samples blown with water, methylene chloride, and a mixture of water and methylene chloride decreased from 240.1 to 33.4 kg/m³ with an increase in the blowing agent contents. However, the RPUF density increased with increasing contents of 1,4‐butane diol. The cell morphology and thermal properties of the RPUF samples were investigated with scanning electron microscopy, thermogravimetric analysis, derivative thermogravimetry, and differential thermal analysis. Scanning electron microscopy results revealed an average increase in the cell size of the RPUF samples from 162 to 278 μm with increased water content. A thermal behavior study indicated that the RPUF samples decomposed in nitrogen and degraded in air through two and three weight‐loss stages, respectively. Foam pyrolysis in nitrogen and combustion in air led to 15 and 0% char residue, respectively. The results indicated that the thermal stability of the RPUFs was better in nitrogen than in an air atmosphere. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007