凝胶型核壳结构粉体抑制A类火的有效性研究

通过设计一种凝胶型核壳结构粉体灭火介质，旨在灭火剂剂型上进行集成创新，克服传统灭火剂在环保、效能以及腐蚀性上的不足。利用高速剪切法将气相二氧化硅、磷酸二氢氨溶液、结冷胶与甲基含氢硅油相结合制备该介质，并对其耐压性和灭火有效性进行表征，研究介质的协同作用机理。结果表明：该介质的粒径在100~200 μm并且充装压力不大于1.2 MPa时的破损率最小。该新型介质具有较好的抑制熄灭A类火的效能，并且在灭火过程中能够发挥协同作用：水作为惰性灭火组分能够迅速蒸发冷却降温；磷酸二氢铵作为化学灭火组分分解吸热并捕捉燃烧反应自由基，切断链式反应扑灭火焰；凝胶能附着在木垛表面形成隔离层，持续降温抑制阴燃和复燃。凝胶型核壳结构粉体灭火介质的灭火效能优于普通ABC干粉，且成本更低，有较好的应用前景。     

灭火剂发展现状与未来

合理选择灭火剂是即时有效扑灭燃烧火焰和防火防爆的关键。对常用的物理灭火剂和化学灭火剂的特点、灭火机理和适用范围作了归纳 ,着重介绍了哈龙和哈龙替代品的灭火机理 ,并对物理灭火剂和化学灭火剂之间的协同作用作了重点阐述     

The extinction of hydrocarbon flames based on the heat-absorption processes which occur in them

An empirical relation has been developed which correlates and predicts the fire-suppression effectiveness of a wide variety of gaseous, liquid and solid agents. The flame-extinguishment model is based on the premise that extinction is dominated by heat-absorption processes and that a flame is extinguished when sufficient heat has been removed by the extinguishant to reduce the temperature to a limit value. This limit value. This limit is the minimum temperature at which the effective rate of the combustion reactions is sufficient to maintain flamepropagation, and it depends in a predictable way on the properties of the suppressant and flame system. The heat-balance equation describing this is derived in two stages. In the first, a preliminary equation is obtained by considering only those substances which are thermally stable and act only as heat-capacity sinks. In the second, the equation is generalized by consideration of all endothermic reaction sinks, e.g. vaporization, dissociation and decomposition. The general equation correlates most of the extinction data found in the literature. The results suggest that for most substances the extinguishing capacity is related to heat-extraction data found in the literature. The results suggest that for most substances the extinguishing capacity is related to heat-extraction and that many of the effects previously attributed to chemical mechanisms may be thermodynamic in nature rather than kinetic.     

Intumescence in poly(butylene terephthalate): the effect of 2‐methyl‐1,2‐oxaphospholan‐5‐one 2‐oxide and ammonium polyphosphate

The flame‐retardant effect of 2‐methyl‐1,2‐oxaphospholan‐5‐one 2‐oxide (OP) and ammonium polyphosphate (APP) in poly(butylene terephthalate) (PBT) was studied by the limiting oxygen index and the UL94 test. A self‐extinguishing formulation (V‐0 rating) was achieved by the addition of 15 wt% APP and 10 wt% OP. The fire‐retardant effect was attributed to the condensed‐phase mechanism of intumescence. Mechanistic studies were performed using thermogravimetry, IR characterization of solid residues and GC–MS characterization of the gaseous and high‐boiling products. OP–APP was shown to cause ammonolysis of PBT, formation of aromatic nitriles in the high‐boiling products and phosphorus ester groups and polyphosphoric acid–phosphorus pentaoxide in the solid residue. Copyright © 2003 Society of Chemical Industry     

国外项目中高低压CO2灭火系统的应用

根据水泥厂燃料生产存储环节中CO2灭火系统的设计经验,简要介绍灭火剂和消防系统的选择,详细分析了水泥工程项目中CO2储量的考虑原则、操作要点和储存系统的选择。最后分析对比了国外总包项目中德国YARA公司的高低压CO2系统的实际应用,这二种系统各有自己的优势和劣势,实际应用中应根据项目特点进行选配。     

高岭石／二甲基亚砜插层复合物的制备及影响因素

以高岭土为原料,制备了高岭土／二甲基亚砜（dimethylsulfoxide,DMSO）插层复合物。利用X射线衍射（x-raydiffraction,xgo）,Fourier红外光谱（Fouriertransforminfraredspectracopy,FTIR）,热重一差热分析（thermogravimetric-...     

固相配位化学反应研究Ⅰ．钴（Ⅱ）－六次甲基四胺配合物的固相合成与应用

室温条件下，六水合二氯化钴与六次甲基四胺固相反应得到钴（Ⅱ） 六次甲基四胺配合物，经ＩＲ、薄层色谱扫描、元素分析、ＤＴＡ和ＴＧ分析表征了该产物。研究了该配合物的可逆示温性能，并将其研制成了可作为防伪材料的水溶性可逆示温油墨。     

Thermal characteristics of bagasse

Bagasse is a solid waste that remains after crushing sugarcane. Since bagasse is used as a fuel in sugar mills, characterization of its thermal degradation is rather important in order to use it efficiently. Thermal analysis of bagasse was carried out using differential thermal analysis (DTA) and thermogravimetry (TG) under oxidizing and inert atmospheres. Kinetic studies were based on weight loss obtained from TG analysis. Thermal degradation of bagasse takes place in two stages: volatilization and carbonization. The reaction rate, activation energy, entropy change, enthalpy change, and Gibbs free energy for the two thermal stages were calculated. The results indicated that activation energy for the volatilization stage is higher than that of decarbonization stage, and that both the rate constant and activation energy for combustion are higher than those of pyrolysis. © 1996 John Wiley & Sons, Inc.     

Polyol Synthesis and Investigation of Ce1−xRExO2−x/2 (RE = Sm,Gd, Nd,La, 0 ≤ x ≤ 0.25) Electrolytes for IT‐SOFCs

In this study, we aimed to examine the effect of dopant type and concentration on the ionic conductivity of ceria‐based electrolytes. Ceria electrolytes doped with samarium (SDC), gadolinium (GDC), neodymium (NDC), and lanthanum (LDC) for solid oxide fuel cells were prepared through the polyol process. Acetate compounds of cerium and dopants were used as starting materials, and triethylene glycol was used as a solvent. Prepared powders and pellets were characterized by TG/DTA, XRD, FTIR, SEM, EIS, and EDS techniques. The results of the TG/DTA and XRD indicated that a single‐phase fluorite structure formed at the relatively low calcination temperature of 500°C. The relative densities of the pellets were higher than 90% and these finding were supported by the SEM images. The lattice parameters of the samples increased with the dopant concentration. According to the electrochemical analysis results, the samples with maximum conductivity values were SDC‐20, GDC‐15, NDC‐15, and LDC‐15. The results of the impedance spectroscopy revealed that the SDC‐20 sample exhibited the highest ionic conductivity with a value of 4.29 × 10^?2 S/cm at 800°C in air.     

溶胶—凝胶法制备SiO2玻璃

采用ＴＥＯＳ－ＥｔｏＨ－Ｈ２Ｏ－ＨＣｌ体系原料,应用低温合成技术制备了ＳｉＯ２玻璃。对合成材料进行了差热－失重分析,Ｘ射线衍射分析,红外透射光谱分析及理化实验,结果表明,无序ＳｉＯ２四面体网络已经形成,固体物理状态可控制为晶态,非晶态。     

Effect of Sm and Gd dopants on structural characteristics and ionic conductivity of ceria

Sm- and Gd-doped ceria electrolytes Ce_0.9Gd_0.1O_1.95 (GDC) and Ce_0.9Sm_0.1O_1.95 (SDC) were prepared by using the Pechini method. The microstructural and physical properties of the samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry/differential thermal analysis (TG/DTA) and Fourier Transform Infrared Spectroscopy (FTIR). The TG/DTA and XRD results indicated that a single-phase fluorite structure formed at a relatively low calcination temperature, 400 °C. The XRD patterns of the samples revealed that the crystallization of the SDC powders was superior than that of the GDC powders at 400 °C. The sintering behavior and ionic conductivity of the GDC and SDC pellets were also investigated. The sintering results showed that the SDC samples were found to have higher sinterability than the GDC samples at a relatively low sintering temperature, 1300 °C, a significantly lower temperature than 1650 °C, which is required for ceria solid electrolytes prepared by solid state techniques. The impedance spectroscopy results revealed that SDC has a higher ionic conductivity compared to GDC.     

EBM气溶胶灭火剂吸湿性的研究

烟火型气溶胶发生剂EBM是一种新型高效气溶胶灭火剂，其灭火效率高于哈龙类灭火剂。气溶胶生成物中固体微粒含量很高。吸湿后的固体微粒会对金属材料及线路板等有腐蚀性，影响保护物的正常使用。本文研究了温度和空气相对湿度对气溶胶生成物吸湿性的影响。     

ABS阻燃性能测试中差热/热重-红外光谱技术的应用

分别采用氧指数和差热、热重－红外光谱技术对常用的ABS材料进行测试。结果表明，试验样品差热数据和氧指数数据有对应关系。差热／热重－红外光谱联用可以观测到ABS热分解过程和分解产物，纯ABS和阻燃ABS的分解过程明显不同。通过差热／热重－红外光谱数据可以获取更多的材料在高温下的变化信息，从而有利于对材料阻燃性能和阻燃危寄性进行预测和判断。     

Studies on electrochemical properties of poly (ethylene oxide)-based gel polymer electrolytes with the effect of chitosan for lithium–sulfur batteries

Composite gel polymer electrolytes (CGPE), with different proportions of poly (ethylene oxide), plasticizers namely 1,3-dioxolane (DIOX)/tetraethelyneglygol dimethylether (TEGDME) and a lithium salt (LITFSI) with the addition of filler chitosan were prepared using the solution casting technique in an argon atmosphere. The membranes were subjected to various characterization techniques such as TG/DTA, FTIR and an ac impedance analysis. A lithium symmetric cell (Li/CGPE/Li) was assembled and the interfacial stability of the polymer electrolyte with a lithium anode was measured. The electrochemical stability and the transport properties of the high conducting sample were also measured. TG/DTA shows the thermal stability of the high conducting sample. The optimal value of the plasticizers was to be found in the ionic conductivity point of view.     

Carbothermal synthesis of vanadium and chromium carbides from solution-Derived precursors

Vanadium and chromium tartrate precursors prepared from aqueous solutions have been used as preceramic materials for carbothermal reactions with and without simultaneous nitridation. Their thermal behaviour has been investigated by TG/DTA, X-ray diffraction and measurement of surface areas. Under pyrolysis up to about 600°C, reactive composites consisting of intimately mixed carbon and amorphous M₂O₃ oxides are formed by salt decomposition. The subsequent processes of crystallization of oxides and carbothermal reduction render both the composites and the reduction products porous. The carbothermal reactions leading either to V₈C₇, a V(C,N,O) solid solution, and Cr₃C₂, respectively, proceed at moderate temperatures between 800 and 1100°C. The final products result as assemblages of fine carbide or carbonitride particles, however, with extensive heat treatment the particles grow and the surface areas diminish. Air oxidation of the final products has been studied by simultaneous TG/DTA.     

LiV_3O_8电池材料的固相配位法合成及其动力学研究

以LiCO3和V2O5为原料,采用固相配位化学反应法合成了层状锂钒氧化物LiV3O锂离子正极材料。通过TG-DTA得出该合成反应的机理及其动力学模型。考察了合成条件对产物的影响。结果表明:550℃左右烧结24 h可得到单一相产物LiV3O8。TEM图显示其形貌及粒度都较好。     

Fe2O3催化甲基化合成2，3，5-三甲基苯酚

制备并考察了甲醇甲基化法合成2，3，5-三甲基苯酚的固体酸催化剂，进行了甲基化反应工艺条件的优化研究。实验结果表明，最优工艺条件：反应温度370 ℃、液空速0.2 h^-1、n(3，5-二甲基苯酚)∶n(甲醇)∶n(水)=1∶2∶1；原料3，5-二甲基苯酚的转化率达95.96％，目的产物2，3，5-三甲基苯酚的收率为72.01％。并采用XRD、SEM、DTA和TG等测定方法对催化剂进行了研究，发现催化剂表面上积炭污染是造成催化剂活性下降的主要原因。     

Characterization of Aluminum Nanopowder Compositions

The thermal behaviour of two different Al nanopowders and a micron‐sized Al powder was studied using DSC, simultaneous TG‐DTA, and accelerating rate calorimetry (ARC). The results show that the reactivity of Al powder increases as the particle size decreases. The thermal stability of the smaller Al nanopowder (Als) in water and in a humid atmosphere was determined using ARC and TG‐DTA, respectively. Atomic Absorption Spectrometry (AAS), X‐Ray Photoelectron Spectrometry (XPS) and Auger Electron Spectrometry (AES) were used to characterize the surface chemistry of Alex. The outgassing behaviour for mixtures of RDX and the various Al powders was investigated using TG‐DTA‐FTIR‐MS. Evolution of NO₂ and N₂O from a chemical interaction between Al nanopowders and RDX was observed. The effect of Als and Alex on the thermal stability of TNT, RDX, Comp B, and AP was determined using ARC. Addition of Als significantly lowered the onset temperature for TNT and RDX decomposition. Electrostatic discharge (ESD) sensitivities of Al nanopowders and their mixtures with TNT, Comp B, RDX and AP were determined. The results show that the AP/Als mixture is very sensitive to ESD. Standard dust explosibility tests demonstrated that Alex is highly explosible.     

蛭石粉末及离子溶液改性后膨胀率和灭火有效性分析

为了研发高效干粉灭火剂粉体,提升干粉灭火剂的灭火效果,本文以蛭石粉为研究对象,采用NaCl、NaHCO₃、MgCl₂和KCl四类离子溶液对不同粒径的蛭石粉进行改性处理,并分析了原始蛭石粉末以及改性后的蛭石粉的膨胀率和表面微观结构。随后开展了ABC干粉灭火剂、未改性蛭石粉、MgCl₂改性蛭石粉、NaCl改性蛭石粉、KCl改性蛭石粉、NaHCO₃改性蛭石粉扑灭油池火实验,分析了灭火时间、灭火剂用量以及复燃情况。研究结果表明：粒径150 μm的蛭石粉末膨胀率最大,且经过改性的蛭石粉末的膨胀率要明显大于原始蛭石粉末,其中MgCl₂改性后的蛭石粉膨胀率最大,接近2.4左右;从灭火时间来看,灭火效果从低到高依次为ABC干粉灭火剂、未改性蛭石粉、MgCl₂改性蛭石粉、NaCl改性蛭石粉、KCl改性蛭石粉、NaHCO₃改性蛭石粉;从灭火剂用量角度可得出：改性蛭石粉灭火用量要明显小于未改性蛭石粉。其中,NaHCO₃改性蛭石粉用量与ABC干粉灭火剂用量相对接近。从复燃角度来看,膨胀蛭石粉末的密度较小,可长时间悬浮在油品表面,有效阻止复燃,效果明显优于传统的ABC类干粉灭火剂。     

X-ray diffraction spectroscopic and thermal studies on 1,3,5-trinitro-hexahydropyrimidine (TNP)

TNP, a heterocyclic nitramine containing a C NO₂ functionality, has been studied as regards the kinetics and mechanism of thermal decomposition, morphology and the gaseous products evolved therof, using thermogravimetry (TG), differential thermal analysis (DTA), infrared spectroscopy (IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and hot stage microscopy. The elementary cell parameters obtained form the XRD pattern are: a = 18.818 ± 0.005 Å, b = 18.818 ± 0.005 Å and c = 4.867 ± 0.005 Å. The crystal belongs to the hexagonal system with c/a ratio = 0.259. IR spectra of TNP have also been recorded and the bands assigned. Kinetics of thermolysis has been followed both by isothermal TG and IR. The best linearity with a correlation coefficient of 0.986 was obtained for the three-dimensional diffusion controlled Jander-equation. Kinetic parameters were evaluated from the induction period as well as from isothermal TG. Activation energy was found to be 202.05 kJ/mol and log A(in s-¹) 22.78 from TG and 181.133 kJ/mol and log A (in s¹) 20.97 from IR, respectively. The corresponding values were 171.17 kJ/mol and log A (in s-¹) 21.20 from the induction period data. The effect of a series of additives incorporated to the extent of 5 %, on the initial thermolysis of TNP, has also been studied. Evolved gas analysis by IR showed that CO₂, NO₂, NO and N₂O are produced in larger amounts than CO and HCN. The cleavage of the N N bond appears to be the primary step in the thermolysis of TNP.