超临界流体技术及其在环境保护中的应用

从超临界流体萃取、超临界水氧化、催化超临界水氧化和超临界流体色谱等四个方面介绍超临界流体技术在环境分析、环境污染治理中的应用和发展方向。     

含能材料CL-20的热安全性测试分析

CL-20是一种高能量、高性能的炸药。为了研究CL-20的热分解性能,分别采用DSC-TG、DSC-TG-QMS联用系统和高压型差示扫描量热仪(DSC 204 HP)对CL-20的热安全性进行了测试分析,并计算了CL-20的热力学参数和动力学参数。结果表明,CL-20固体炸药在不同升温速率下的TG曲线基本相似,都只有一个台阶。在升温速率为10 K/min时,CL-20在放热峰温处的活化焓、活化熵和活化自由能分别是177.26 k J/mol、52.61 J/(K·mol)和149.7 kJ/mol。CL-20热分解后的气体产物主要有NO、CO、CO_2和H_2O,离子流强度约为10-9A,其中H_2O的离子流强度最大。不同压力时CL-20热分解的过程不同,在压力高的情况下CL-20分解放热更多,反应过程越剧烈,热安全性越差。与常压下相比DSC放热峰值温度降低。     

HMX的氟橡胶包覆技术及其撞击感度研究

采用超临界流体SAS法,以氟橡胶（FPM2602）为钝化包覆剂,对主体炸药超细奥克托今（HMX）的粒子表面均匀包覆,制备出超细HMX为基传爆药。对系统温度、系统压力、溶液浓度等参数进行实验研究,用红外光谱（FT-IR）和扫描电镜（SEM）对包覆后超细HMX进行了表征,并对其撞击感度进行了测试。结果表明：溶液浓度是影响包覆效果的最主要因素;当系统温度45℃,系统压力9.5MPa,溶液浓度为0.4g/ml,通气时间为20min条件下,氟橡胶均匀包覆在超细HMX颗粒表面,包覆后颗粒呈0.4-1μm球状,包覆后造型粉特性落高H50为38.50cm（12型工具、2.5kg落锤）,撞击感度比原料（H50为26.30cm）明显降低。     

可燃气体(液体蒸气)爆炸测试装置的改进研究

以可燃气体(液体蒸气)爆炸测试装置改进为主线,综述国内外各种测试装置的优缺点。对不同装置、测试方法以及测试原理进行比较分析,研讨可燃气体爆炸的特点和爆炸参数测试方法以及对现有测试装置的改进方案。即对20 L爆炸测试装置的配气系统和控制系统进行了合理改进,使引射混合配气与循环混合配气相结合,使可燃气体(液体蒸气)与空气混合更均匀,控制操作更简便,还指出了今后研究工作中应注意的一些问题和研究重点。     

基于傅里叶变换红外光谱技术的混合毒性气体定量分析研究

基于傅里叶变换红外光谱技术,选取低浓度的CO、CO2、NO、NO2、SO2、HCl、HBr、HCN 8种典型有毒有害气体进行定量分析.经过合理选择光谱区间、数据预处理、样本筛选以及确定模型参数后,建立PLS回归模型,并对模型回归曲线进行多项式修正.模型中各组分实际浓度与预测浓度的拟合回归系数达到0.99,校正集误差均方根SRMSEC低于15×10-6.利用验证集对模型的预测性能进行检验,样本各组分的预测浓度误差小于满量程的±2%,各组分的预测误差均方根SRMSEP不超过20×10-6.     

荧光标记无磷缓蚀阻垢剂(PESA-X)的制备及其性能研究

针对绿色环保的无磷缓蚀阻垢剂无法用常规总磷检测方法监测的问题,为了实现对循环冷却水系统中的有效无磷缓蚀阻垢剂含量的实时检测与控制,将无磷缓蚀阻垢剂PESA与荧光示踪剂CBS-X按照一定比例复配制备荧光标记无磷缓蚀阻垢剂(PESA-X)。采用荧光光谱法和碳酸钙沉积法来研究PESA-X的性能,同时还建立以荧光强度为指标的动态阻垢模型。结果表明,PESA-X的荧光强度与其质量浓度呈正线性相关,其线性拟合方程为Y=18.805 X-5.26,R^(2)=0.9997。且PESA的阻垢性能基本没有受到荧光示踪剂CBS-X影响。PESA-X的稳定性良好,受pH、温度、光照时间等因素影响较小。通过动态阻垢实验可知,荧光强度(Y)与Ca^(2+)质量浓度(X)的线性方程为Y=2052.38X-198.20,表明了荧光示踪剂CBS-X与PESA同步消耗。因此,通过对PESA-X的荧光强度分析可以实时显示水处理系统内无磷缓蚀阻垢剂PESA的含量,从而实现用荧光强度定量循环水系统中无磷缓蚀阻垢剂PESA的有效质量浓度,为工业循环冷却水系统实时检测与控制无磷缓蚀阻垢剂的含量提供理论基础。     

基于层层自组装技术制备的吸油型聚氨酯泡沫材料及其性能研究

利用高效吸油材料处理溢油事故是一种简单有效的方法。针对现有吸油材料吸油效率较低、制备方式复杂的问题,采用层层自组装技术,将钠基蒙脱土填充的涂层构筑于软质聚氨酯泡沫表面,经过后续疏水改性处理,制备了具有超疏水超亲油表面的聚氨酯泡沫材料。材料测试结果表明:组装4层涂层改性的聚氨酯泡沫水接触角达到135°,对不同种类油品的吸油重量能达到自身重量的30~60倍;油水混合物中的吸油效果也显示其能有效处理水面、水下油污。宏观燃烧实验测试结果表明制备的改性聚氨酯泡沫具有良好的阻燃性能。采用上述简单易行的制备技术制得的吸油材料,可成功应用于油水分离,具有良好的应用前景。     

低温环境下手部温度主动加热技术的研究

本文介绍了一种低温环境下手部温度主动加热技术.通过热力学有关理论知识分析得出:人的手部是极易遭受低温损伤的重要部位之一.本研究设计了一种全新的手部温度主动加热系统,打破了传统的被动式手部加热防护体系,实现了手部温度的自动调节.该系统既可以保障人手部的工效性能,同时又可以满足手部精细操控作业的要求.     

Influence of different ignition delay times on the pressure rise rate in hybrid mixture explosions in the 20-L sphere

For the development of a standardized method for measuring the explosion safety characteristics of combustible hybrid dust/vapor mixtures, the influence of the ignition delay time needs to be investigated. The ignition delay time, defined as the time between the injection of dust and the activation of the ignition source, is related to the turbulence of the mixture and thus to the pressure rise rate. The ignition source for pure vapors, however, has to be activated in a quiescent atmosphere according to the standards. Nevertheless, when measuring the explosion safety characteristics of hybrid mixtures, it is important that the dust be in suspension around the igniter. Like pure dust/air mixtures, hybrid dust/vapor/air mixtures need to be ignited in a turbulent atmosphere to keep the dust in suspension.This work will therefore investigate the influence of ignition delay times on the severity of hybrid explosions. It was generally found that at shorter ignition delay times, (dp/dt)_ex increased due to higher turbulence and decreases as the dust sinks to the bottom of the 20 L-sphere. This effect is more pronounced for hybrid mixtures with higher vapor content compared to dust content.     

Experimental and CFD-DEM study of the dispersion and combustion of wheat starch and carbon-black particles during the standard 20L sphere test

The 20L sphere is one of the standard devices used for dust explosivity characterization. One concern about the effectiveness and reliability of this test is related to the particle size variation due to particles' agglomeration and de-agglomeration. These phenomena are related to the turbulent regime of the dust cloud during the dispersion. This variable must be considered since it determines the uncertainty level of the ignitability and severity parameters of dust combustion. In this context, this study describes the influence of the cloud turbulence on the dust segregation and fragmentation through a study combining both, experimental and computational approaches. The behavior of the gas-solid mixture evidenced with the standard rebound nozzle was compared with that observed with six new nozzle geometries. Thereafter, the time-variation of the Particle Size Distribution (PSD) within the 20L sphere was analyzed for two different powders: carbon-black and wheat starch. On the one hand, the turbulence levels and PSD variations were characterized by Particle Image Velocimetry (PIV) tests and granulometric analyses, respectively. On the other hand, a computational approach described the dispersion process with CFD-DEM simulations developed in STAR-CCM + v11.04.010. The simulation results established that the homogeneity assumption is not satisfied with the nozzles studied. Nonetheless, the particles segregation levels can be reduced using nozzles that generate a better dust distribution in the gas-solid injections. Subsequently, an additional first-approach CFD model was established to study the behavior of the combustion step for a starch/air mixture. This model considers the gas-phase reactions of the combustible gases that are produced from the devolatilization of wheat starch ($CO,C{H}_4,C_2{H}_4,C_2{H}_6,C_2{H}_2,$ and $H_2$) and allowed to establish the approximate fraction of the particle mass that devolatilizes, as well as to confirm that the modeling of the pyrolysis stage is essential for the correct prediction of the maximum rate of pressure rise.     

生物修复技术在城市水体环境治理中的应用探究

近年来在城市水体环境治理的过程中,已经开始采用物理类型、化学类型与生物类型的修复技术,相比之下,生物类型修复技术的应用工程量较少、成本较低并且具有环境友好性的特点,具有较高的应用优势。因此,在城市水体环境治理的工作中,应该科学采用先进的生物修复技术,将其在城市水体环境治理中的积极作用充分发挥出来,为城市的后续发展夯实基础。     

Experimental investigation and modelling of aluminum dusts explosions in the 20 L sphere

An experimental investigation was carried out on the influences of dust concentration, particle size distribution and humidity on aluminum dust explosion. Tests were mainly conducted thanks to a 20 L explosion sphere. The effect of humidity was studied by storing the aluminum particles at constant relative humidity until the sorption equilibrium or by introducing water vapour in the explosion vessel. The tested particles sizes ranged from a volume median diameter of 7 to 42 μm and the dust concentrations were up to 3000 g m^?3.Among other results, the strong influence of the particle size was pointed out, especially when the Sauter mean diameter is considered. These results stressed the predominance of the specific surface area on the mass median particle diameter.The effect of water on aluminum dust explosion was decoupled: on the one hand, when water adsorption occurs, hydrogen generation leads to an increase of the explosion severity; on the other hand, when the explosion of dried aluminum powder occurs in a humid atmosphere, the inhibiting effect of humidity is put forward.A model based on mass and heat balances, assuming a shrinking core model with chemical reaction limitation, leads to a satisfactory representation of the pressure evolution during the dust explosion.     

Quantifying the effect of strong ignition sources on particle preconditioning and distribution in the 20-L chamber

Computational fluid dynamics is used to investigate the preconditioning aspect of overdriving in dust explosion testing. The results show that preconditioning alters both the particle temperature and distribution prior to flame propagation in the 20-L chamber. A parametric study gives the fluid pressure and temperature, and particle temperature and concentration at an assumed flame kernel development time (10 ms) for varying ignitor size and particle diameter. For the 10 kJ ignitor with 50% efficiency, polyethylene particles under 50 μm reach 400 K and may melt prior to flame propagation. Gases from the ignitor detonation displace the dust from the center of the chamber and may increase local particle concentration up to two times the nominal value being tested. These effects have important implications for explosive testing of dusts in the 20-L chamber and comparing to larger 1-m³ testing, where these effects may be negligible.     

煤巷掘进跨步预抽煤层瓦斯技术研究与应用

在采取瓦斯抽采安全技术措施情况下,针对煤巷掘进难以实现煤层的边掘边抽问题,提出煤巷掘进跨步预抽煤层瓦斯的方法。该方法利用钻场抽采孔在始端汇集末端发散的分布特点,通过钻场沿煤巷掘进方向的前后错位及钻孔布置的优化设计,实现钻孔在工作面前方煤体密集段与分散段的交错重叠,保障煤巷掘进控制区煤体瓦斯的无死角连续抽采及煤巷的持续掘进。现场试验表明:该技术在掘进面前方煤体具有较好的抽采效果,成功实现了煤巷的连续不间断掘进,在煤巷掘进期间未发生工作面瓦斯涌出事故及煤与瓦斯突出征兆。该技术为高瓦斯矿井及按突出矿井管理的煤层实现煤巷的边掘边抽提供了借鉴。     

超临界水中含油污泥与甲醛共氧化研究

在温度为390～450 ℃,压力为25 MPa,反应时间为1～10 min的条件下,在间歇式反应釜中采用超临界水共氧化方法处理含油污泥,考察共氧化添加物种类、时间、甲醛质量浓度和温度对氧化效果的影响.结果表明,添加甲醛对含油污泥的转化具有明显的促进作用,450 ℃反应10 min,含油污泥COD去除率达99.0%.甲醛质量浓度至少要与含油污泥初始COD处于同一数量级时,才具有显著的促进作用.氧化中间产物CO和醋酸产率随甲醛质量浓度提高而增加.反应温度低时甲醛的促进作用明显.随着反应温度的提高,CO产率增加,醋酸产率降低.     

大型石油罐区安全控制技术及其应用研究

采用道化学危险指数法对油库的火灾、爆炸危险性进行了分析.选取油库最具代表性的原油储罐区和原油泵房为分析单元,得出其初期计算结果的危险等级都为"高",补偿计算结果的危险等级都降为"较低".这说明油库所计算单元在采取安全措施和预防手段的条件下,危险等级大大降低,达到可以接受的程度.利用DNV公司的SAFETI软件对油库可能发生的重大事故进行了仿真模拟研究,得出了事故可能影响的范围和结果,同时提出了危险削减措施.根据油库事故的历史数据,事故类型选用了原油储罐以及原油管线泄漏.     

RBI技术在我国企业的应用研究与改进思考

基于风险的检测技术(RBI)是目前化工行业逐渐采用并得到认可的一种新的设备检测技术。在对RBI体系研究的基础上,阐述了RBI的系统思想、实施步骤与应用价值;在工艺危害性分析的基础上,采用挪威船级社的ORBIT Onshore软件对常减压装置进行了定量RBI分析,识别出装置设备和管道的主要腐蚀损伤模式,确定设备和管道的风险大小分布以及风险检测策略;并根据RBI在化工等行业企业的应用实践对RBI技术在我国应用过程中存在的不足提出了相关改进建议。