催化超临界水氧化法处理HMX废水实验研究

超临界水氧化法(SCWO)是一种处理高浓度有机废水的新技术。对超临界水的性质状态、显著特点、处理机理、工业应用以及该技术目前存在的问题等进行了较全面的阐述。采用间歇式超临界水氧化实验装置处理奥克托金(HMX)炸药废水,对催化剂的选择、反应温度、反应压力、反应时间对处理效果的影响进行了研究。     

超临界水氧化处理DDNP废水的动力学研究

采用间歇式超临界水氧化实验装置,以O2为氧化剂,在703～823 K、压力24 MPa、停留时间10～50 s的条件下,进行了超临界水氧化DDNP模拟废水实验,COD去除率可达99%;建立了COD去除率宏观动力学方程.结果表明,超临界水氧化对处理DDNP是有效的,在超临界条件下,DDNP废水的COD去除率随着反应温度的升高和停留时间的延长而增加;在氧化剂过量2倍的情况下,DDNP超临界水氧化反应对有机物的反应级数为1.33级,对氧气为0.21级;反应活化能Ea为30.7 kJ/mol,指前因子A为61.97.     

超临界水氧化处理DDNP废水的动力学研究

采用间歇式超临界水氧化实验装置，以O2为氧化剂，在703-823K、压力24MPa、停留时间10-50s的条件下，进行了超临界水氧化DDNP模拟废水实验，COD去除率可达99％；建立了COD去除率宏观动力学方程。结果表明，超临界水氧化对处理DDNP是有效的，在超临界条件下，DDNP废水的COD去除率随着反应温度的升高和停留时间的延长而增加；在氧化剂过量2倍的情况下，DDNP超临界水氧化反应对有机物的反应级数为1．33级，对氧气为0．21级；反应活化能E。为30．7kJ／mol，指前因子A为61．97。     

PTA残渣的超临界水氧化处理试验研究

采用间歇式的超临界水氧化反应器对PTA残渣和生产废水的掺混液进行了超临界水氧化处理试验研究。结果表明:超临界水氧化技术可有效处理PTA残渣掺混液,掺混液的COD去除率随反应压力、温度和时间的增加而增加,COD去除率接近90%。探讨了氧化剂过量时PTA残渣掺混液的超临界水氧化反应动力学规律,得出32 MPa条件下相应的动力学参数:频率因子为206.97±5.78,活化能为(75.3±10.1)k J/mol;并对超临界反应过程进行能耗分析,得出32 MPa,420℃条件下反应不能实现自平衡。     

超临界水氧化技术的研究与应用进展

超临界水氧化技术是利用超临界水作为反应介质，彻底破坏有机物质的一种新型氧化技术。介绍了超临界水的特性和超临界水氧化的基本原理及反应器装置，综述了超临界水氧化的反应机理、动力学、工程应用，以及有毒有机污染物处理等方面的研究进展。     

印染污泥的超临界水氧化实验研究

通过间歇式反应器和小型盘管式反应器进行了印染污泥的超临界水氧化特性实验研究。在明确污泥输运特性的基础上,探索反应温度、氧化系数、污泥含水率及辅助燃料对超临界水氧化反应的影响规律,评估反应后污泥中重金属元素的浸出毒性。研究结果表明,常温条件下,91%含水率的污泥粘度满足高压污泥隔膜泵的输运要求。温度与氧化系数对超临界水氧化反应起积极作用,而含水率对有机物分解是不利的,在585℃、5 min、含水率91%及氧化系数3.0条件下,污泥COD去除率达到99.61%。另外,2.57%的异丙醇对污泥具有明显的共氧化作用,在400℃时,COD去除率增加至98.54%。最后,重金属在反应过程中可转化为稳定的结合态。综上所述,超临界水氧化技术可实现对印染污泥的无害化处置。     

超临界水氧化在难处理废水领域中的工程应用进展

系统总结了超临界水的溶液性质、超临界水氧化反应机理以及工业化过程中的基础工艺流程,指出了超临界水氧化技术具有处理彻底、反应迅速、无二次污染的特点,虽然在处理难处理废水上具有广泛的应用前景,但在工程化过程中不可避免地面临设备腐蚀、盐沉积堵塞、基础数据缺失、结焦堵塞、催化剂二次污染等问题。将超临界水氧化工艺装置撬装在可移动运载工具上,用于适应国内污染点分散的特点,具有巨大的市场价值。     

城市污泥超临界水氧化技术示范装置及其经济性分析

简单介绍了超临界水氧化技术处理城市污泥的技术优势,重点阐述了一套自主设计并即将建成的城市污泥超临界水氧化技术示范装置的工艺流程和其核心部件反应器的创新设计特点,同时测算了该示范装置的设备投资和运行成本,提出了进一步降低其运行成本的措施.结果表明其设备投资及运行成本均低于焚烧法,是一种经济可行的城市污泥处理技术.     

高浓度印染废水及污泥的超临界水氧化系统设计及经济性分析

简单介绍了超临界水氧化处理高浓度印染废水及污泥的技术优势,阐述了一套自主设计的超临界水氧化系统工艺流程和其核心部件反应器的创新设计特点,重点论述了印染有机物超临界水氧化反应条件的确定以及水热燃烧反应器材料的选择,同时估算了该系统的设备投资和运行费用。结果表明,超临界水氧化技术是一种经济可行的高浓度印染废水及污泥处理技术。     

超临界水氧化处理偶氮染料废水的实验研究

在间歇式反应器中进行偶氮染料C.I.活性橙7的超临界水氧化实验,探索染料分子中的偶氮基团在氧化反应中的转化规律.选取反应温度、氧化系数、初始COD质量浓度、反应时间和pH值为过程参数,总氮去除率和氨氮质量浓度为响应量,通过中心组合设计方法进行实验设计,设计了一个五因素、五水平包含22个实验点的实验矩阵.采用响应面分析法...     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Analyse Expérimentale et Numérique du Comportement de Membranes Thermoplastiques en ABS et en HIPS dans le Procédé de Thermoformage

In this work, we are interested, on the one hand in the characterization of circular polymeric ABS and HIPS membrane under biaxial deformation using the bubble inflation technique, on the other hand in modelling and numerical simulation of the thermoforming of ABS and HIPS materials using the dynamic finite element method. Hyperelastic models (Mooney‐Rivlin, Ogden) are considered. First, the governing equations for the inflation of a flat circular membrane are solved using a variable‐step‐size‐finite difference method and a modified Levenberg‐Marquardt algorithm to minimize the difference between the calculated and measured inflation pressure. This will determine the material constants embedded within the models used. For numerical simulation, the lagrangian formulation together with the assumption of the membrane theory is used. Moreover, the influence of the hyperalastic model on the thickness and on the stress distribution in the thermoforming sheet are analysed for ABS and HIPS materials.     

ACR对PVC加工性能的影响

详细研究了丙烯酸酯类PVC加工助剂———ACR的特性黏度、组成对PVC共混物加工性能的影响。结果表明,随着甲基丙烯酸甲酯用量的下降和丙烯酸丁酯用量的提高,其塑化速度增大,但熔体强度降低,在组成相同的情况下,特性黏度越大,塑化越慢,熔体强度越大;丙烯酸酯类加工助剂对PVC制品的拉伸强度和维卡软化点无明显影响,高黏度的加工助剂有提高PVC制品拉伸强度和维卡软化点的趋势。     

Kinetics of organic solvent-soluble and native lipase

Organic solvent-soluble lipase was prepared with a synthetic detergent. The solvent-soluble lipase was presumed to be a complex of the enzyme and the detergent. To investigate the effect of the detergent attachment to the enzyme on the reaction properties, the kinetics of the solvent-soluble lipase and of the native lipase were estimated by using glycerides in a homogeneous solution of buffer and tetrahydrofuran. Analysis of the direct interaction between the enzyme and the substrate could serve to characterize the steric structure around the active site of the lipase. The K_m values also differentiated the solvent-soluble lipase from the native lipase. These findings show for the first time that the detergent surrounding the enzyme molecule may affect not only the solubility of the enzyme, but its kinetics as well.     

液滴撞击微结构疏水表面的动态特性

对去离子水滴撞击不同几何尺寸显微结构方柱和方孔状疏水表面的动态特性进行了研究。结果表明：当液滴以不同速度撞击微方柱疏水表面时,液滴展现铺展和回缩过程,且随着韦伯数（We数）增大,最大铺展直径增大,并伴随卫星液滴出现,但到达最大铺展直径的时间一致;而当液滴以相同的速度（We数相同）撞击间距不同的微方柱疏水表面时,液滴的最大铺展直径随着间距的增大而减小,且铺展过程会液滴浸润状态变得不稳定,发生由Cassie向Wenzel状态的浸润转变。当微方柱间距较小时,液滴受到的黏附功越小,越易发生向Cassie状态的转变;液滴撞击微方孔疏水表面时,液滴以规则的圆环状向外铺展和回缩,最后呈现近似规则的椭球状,不会发生向Wenzel状态的浸润转变,利用建立的物理模型对前述现象进行了分析。     

一种自适应柱状密封气膜特性分析

提出一种自适应柱状气膜密封,构建气膜-密封环为研究对象,考虑了偏心间隙发散问题,并定义Rayleigh台阶对气膜周期的突变性,建立了气膜雷诺方程和膜厚变化函数关系式的动力润滑数值模型,获得了摩擦副气膜润滑特性,研究结果表明：气膜力随转速和压力升高而增加,泄漏量随压力升高而增加但是随转速增加而下降,说明密封内部压力流占主导地位。随后,利用曲面槽型雕刻技术,结合高速试验台对密封进行测试,结果表明：理论计算模型与试验结果吻合度较高,斜槽区域存在更多擦痕与磨损,说明斜槽浮动性弱于直列槽;但斜槽的切向流动小于直列槽,导致斜槽泄漏量小于直列槽。该研究成果为自适应柱状气膜密封的气体流动规律和应用提供了理论基础。     

水平及竖直基底上微小固着液滴的蒸发特性分析

为揭示非水平表面上微小蒸发液滴的传热传质特性,本文在准稳态模型的假设下构造三维液滴模型,综合考虑了蒸气扩散、蒸发冷却以及气相域中的自然对流这3种传输机理,对水平以及竖直基底上液滴的蒸发过程进行数值研究。通过分析气液界面上温度分布、蒸发通量分布及总蒸发率的变化,重点探究了基底过热度以及重力的改变对液滴蒸发特性的影响。结果表明：与水平基底上温度的对称分布不同,竖直基底上气液界面温度分布表现出明显的非对称性,且非对称性随基底过热度的升高而增强,最低温度点不再位于液滴顶点,而向一侧偏移。此外,水平基底上气液界面局部蒸发通量呈对称分布,各截面分布相似,而竖直基底上局部蒸发通量分布则呈现出显著的非对称性以及各截面异性,非对称性随着基底过热度的升高而增强,这是重力改变后气相域自然对流发生改变的结果。与水平基底相比,竖直基底上蒸发率更高,总蒸发时间更少。最后,基底由水平变为竖直时,液滴内部流场由对称双涡转变为非对称单涡,单涡流速显著大于双涡流速,液滴内流速随基底过热度的上升而增大,单涡环流造成了气液界面温度分布的改变以及最低温度点的偏移。     

Lipid distribution on textiles in relation to washing with lipases

Effectiveness of lipase in detergency was studied using three test soils (lard, artificial sebum, and olive oil) on a woven cotton fabric. Distribution of oily soil on fabrics was determined for three different treatments (unwashed, washed with detergent without lipase, and washed with detergent plus lipase). Osmium tetroxide was used to label lipid soil for analysis in the scanning electron microscope. Both longitudinal and cross-sectional backscattered electron images for unwashed samples showed that soil was present on surfaces of the cotton fibers and in interfiber spaces of the yarn bundle. Lard soiled samples had large deposits on the fabric surfaces, while artificial sebum and olive oil appeared more uniformly distributed throughout the textile. Oil was deposited in the interfiber capillaries of the yarn bundle and in the crenulation, secondary walls, and lumen of the fibers. Energy dispersive X-ray microanalysis was used to determine relative concentrations of oil at selected morphological locations within the fiber structure and at the fiber surface. Soil distributions within the fibrous structures differed with type of soil and laundry treatment. Backscattered electron images dramatically demonstrated the effect of lipase on cleaning. After washing with detergent plus lipase, yarn surfaces had much less residual soil; residual soil that remained was in the irregularities of the cotton fiber surfaces. Concentrations of oil in the secondary walls, crenulations, lumen, and the fiber surfaces were lower after lipase treatment for all three soils. While washing with detergent removed soil from the yarn and fiber surfaces and the crenulation of the cotton fiber, only the samples washed with detergent plus lipase had lower concentrations of soils within the secondary wall and lumen of the cotton fibers. Fabrics soiled with olive oil and washed with detergent plus lipase had the lowest concentrations of residual soil across the textile structure; the residual soil observed was mainly in the irregularities on the fiber surfaces.     

二氧化钛改性α-氧化铝载体对银催化剂催化乙烯环氧化反应性能的影响

为了排除载体孔结构变化对催化性能的影响,研究了二氧化钛改性α-氧化铝载体对银催化剂催化乙烯环氧化反应性能的影响。研究结果表明,二氧化钛表面改性α-氧化铝载体对载体的比表面积、孔结构无明显影响;载体表面改性导致催化活性组分银在载体表面均匀分散,分散状况明显改善;经二氧化钛改性后载体表面与银的相互作用增强;对单负载银催化剂,由改性载体制备的银催化剂的活性和选择性均下降,改性对催化性能明显不利;对于共浸渍法制备的多组分银催化剂,低温焙烧对催化性能不利,而由经1000℃高温焙烧的二氧化钛改性载体制备的银催化剂的催化活性明显提高。研究表明,载体表面等电点降低及其与银的强相互作用是造成催化剂上金属银良好分散的主要原因;此外,银催化剂助剂的存在减弱了二氧化钛改性载体与银之间的强相互作用、抑制了环氧乙烷（EO）深度反应的活性,两者协同作用提升了多组分银催化剂的催化反应性能。     

煤油贮箱冷氦鼓泡增压过程数值研究

火箭飞行过程中,约90 K的低温氦气用以加压室温下的煤油贮箱使煤油流出,保障发动机燃料供应。为尽可能减少氦气用量,设计低温氦气从液相中喷入,使得氦气在贮箱内上升过程先和液态煤油充分换热升温,再进入气相空间增压。但该过程可能引起两个不利的结果,首先浸没在煤油中的低温氦气管路表面可能结冰,结冰沉底或可能堵塞发动机滤网;其次氦气可能被煤油携带,从而排出口位置可能出现气液两相流。这两种情况都对火箭发动机稳定运行造成负面影响,因此是不允许的。对低温氦气在贮箱中心喷入和环向多孔喷入两种结构的气液两相流过程进行了数值研究,构建了基于Euler-Euler模型的两相传热非稳态模型,数值结果与地面实验观察到的现象进行了定性对比,定性验证了模型的准确性。重点考察了煤油排出过程两种喷入结构的气液两相流分布以及煤油结冰可能性。研究结果从机理上解释了实验现象,并为煤油贮箱增压排出方案设计提供了参考。