浪涌保护措施在尿素压缩机控制系统中的应用

由于无法预测的浪涌能量有着强大破坏能力,出现的时间、位置无法预知,对各种自动控制系统构成直接威胁,导致系统瘫痪、生产停顿、设备误操作等。本文探讨浪涌保护器在尿素压缩机控制系统中的应用。     

防雷保护器在聚丙烯装置中的设计探讨

初步探讨了浪涌保护器的设计原理、品质要求和在聚丙烯项目中的应用实例     

氯气透平机保护气用干燥空气的制备

介绍了取代氮气作氯气透平机保护气的空气的干燥工艺,采用空气降低了生产成本。     

PTA装置中空气压缩机组的振动控制

通过对PTA装置中大型空气压缩机组的介绍,对振动保护及喘振控制原理进行了分析并提出了保护措施。     

滑动弧放电等离子体法用于二甲醚重整制氢简

Gliding arc gas discharge plasma was used for the generation of hydrogen from steam reforming of dimethyl ether （DME）. A systemic procedure was employed to determine the suitable experimental conditions. It was found that DME conversion first increased up to the maximum and then decreased slightly with the increase of added water and air. The increase of total feed gas flow rate resulted in the decrease of DME conversion and hydrogen yield, but hydrogen energy consumption dropped down to the lowest as total feed gas flow rate increased to 76 ml. min^-1. Larger electrode gap and higher discharge voltage were advantageous. Electrode shape had an important effect on the conversion of DME and production of H2- Among the five electrodes, electrode 2# with valid length of 55 mm and the radian of 34 degrees of the top electrode section was the best option, which enhanced obviously the conversion of DME.     

Mechanism of formation of a heated ground layer by an intense air burst

A mathematical modeling study demonstrated the fundamental possibility of the formation of a heated layer (a meter-long layer of erosion vapor and air with temperatures of a few thousand degrees and a density 20–50 times lower than the normal air density) at the ground surface under the action of the long-distance traveling fireball radiation from an intense explosion at a moderate radiant flux density of about 1 GW/m² for a time of about 10 msec. The results of the numerical study agree with data from observations of the heated layer effect in nuclear-weapon tests. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 4, pp. 100–106, July–August, 2006.     

弱极化法测评大功率二次雾化电弧喷铝涂层的腐蚀防护寿命

利用弱极化原理,通过腐蚀速率测量仪测量大功率二次雾化电弧喷铝涂层的腐蚀电位和腐蚀电流密度,计算其深度腐蚀速率,时电弧喷铝涂层的防腐寿命进行评估,获得了不同厚度电弧喷铝涂层所对应的防护寿命,确定了具有不同防护寿命的复合涂层的最佳防腐设计方案.讨论了该法存在的问题.指出电弧喷铝复合涂层的防护寿命不仅取决于涂层系统的选择及其内在质量,而且与腐蚀环境和防腐蚀涂装质量、工程养护质量密切相关,应用中须根据已用工程金属涂层的实际防护寿命对其进行修正.     

Effect of compression on thermal protection of firefighting protective clothing under flame exposure

The applied compression on firefighting protective clothing affects the physical properties of the designed system, which in return the thermal protective performance (TPP) could be changed. A modified TPP tester was proposed to investigate the effect of compression on performance of protective clothing. Three stages of heat exchange during firefighting, including heat exposure, heat discharge, and skin cooling, were defined to examine contribution of each stage to skin burn injury. Additionally, the influence of compression on thermal protection was compared under planar and cylindrical configurations. The results demonstrated that the applied compression significantly exacerbated skin burn injuries, while the further increase of the pressure had no significant effect on skin burn injuries. The thermal energy during heat discharge ranged from 42.2% to 64.5% of the maximum thermal energy, highly depending on the fabric properties, the applied compression, the heat discharge time, and the body configuration. The decrease of thermal energy during skin cooling stage only composed a small portion of total absorbed thermal energy, which was increased by the applied compression. The conclusions from this study could contribute to understanding the principle of thermal protection in different firefighting stages for reducing skin burn injury.     

H2 production by ethanol decomposition with a gliding arc discharge plasma reactor

A gliding arc discharge (GRD) reactor was used to decompose ethanol into primarily H₂ and CO with small amounts of CH₄, C₂H₂, C₂H₄, and C₂H₆. The ethanol concentration, electrode gap, input voltage and Ar flow rate all affected the conversion of ethanol with results ranging from 40.7% to 58.0%. Interestingly, for all experimental conditions the S_H2/S_CO selectivity ratio was quite stable at around 1.03. The mechanism for the decomposition of ethanol is also described.     

阴极保护法对化肥厂中铝材的有效保护

介绍了化肥厂中普遍存在的铝材设备腐蚀问题及相应的腐蚀机理，针对化学药剂难以完全抑制碳化水箱的局部腐蚀，详细介绍了阴极保护方法，并阐述了阴极保护的机理及阴极保护方案，还根据实际经验，重点介绍了具体实施过程中涉及到的问题，如设备尺寸及保护面积的计算、阴极与阳极的布置、设备的表面处理及涂层。为证明此方法的有效性，作者还专门从直观效果和试片检测两方面介绍采用阴极保护的应用效果。理论和实践证明，阴极保护法是保护化肥企业铝材设备的有效手段。     

部1-16井保护气层暂堵技术

在研究东濮凹陷致密气藏储层损害机理的基础上 ,对不同区块的天然气藏进行保护深层气暂堵液配方优选和热稳定性研究。部 1 -1 6井作为深层气钻井完井液项目在中原油田施工的首口井位 ,储层平均渗透率恢复值为 92 .0 % ,比施工前提高了 1 8个百分点 ,较好地保护了油气层     

氯气冷却干燥处理中的腐蚀与防护

对氯碱企业的氯气冷却、干燥和压缩工序存在的设备腐蚀问题做了比较详细的技术分析．提出了防护技术措施。     

基于等价气云爆炸风险评估的气体防护区域定量划分

目前对危险气体泄漏防护区域的划分方法主要为定性方法,难以对具体场景定量表征,进而无法用于风险防控系统的设计规划。本文在等价气云理论的基础上,基于爆炸事故后果风险评估,提出一种定量划分气体防护区域的方法。综合考虑气体泄漏概率、风速风向联合分布概率等现场特征要素,运用高斯扩散模型,得到气体泄漏扩散的等价气云体积以及气体泄漏扩散风险集合,并进行泄漏场景筛选。针对扩散风险较大的场景进行点火概率分析,利用多能法计算气云爆炸影响范围,对气云爆炸事故进行风险评估得到爆炸事故后果风险集合。在ALARP标准与火气系统探测器场景覆盖率的指导下,依据不同装置区域的风险值确定气体防护区域等级定量划分标准。通过某LNG接收站案例分析,可定量得到不同装置的防护区域等级,实现针对具体泄漏场景的气体防护区域等级定量划分。数值计算表明,气体防护区域定量划分可为火气系统探测器布设提供理论支持。     

空气和废气中醋酸乙烯分析方法的研究

国内对空气和废气中的醋酸乙烯标准分析方法未见报道,国外美国环保署EPA.625将醋酸乙烯归类与VOCS中。采用Tenax采样管吸附,气质联用分析[1],该分析方法实验过程复杂,样品分析成本较高,笔者通过对硅胶和活性炭两种采样管进行采样效率实验,选择活性炭采样管采集气体样品,CS2解析,选择常用的聚乙二醇固定相色谱柱分离,氢火焰离子化检测器检测,醋酸乙烯分离较好,相关系数为0.9998,标准偏差0.01%～0.03%（n=5）,回收率为98.4%～102.0%。该分析方法符合环境监测气体样品质量控制要求,能适合环境空气和工业废气中醋酸乙烯监测。     

电弧法制备单壁碳纳米管的机理及进展

本文介绍了单壁碳纳米管的结构和性质,叙述了电弧法制备碳纳米管的方法与原理,及制备技术的发展和改进。     

靖边气田汽水分离器腐蚀机理与防护技术研究

靖边气田中分离器污水水质分析和垢样检测表明,其腐蚀主要由CO2-H2O(Cl-)-H2S系统作用引起的电化学腐蚀及SRB微生物腐蚀。采用Φ819 mm×60 mm×30 mm×51 mm的镯式铝牺牲阳极和45 mg/L氮氚杀菌剂联合防护,腐速由1.673 mm/a降到0.097 mm/a,符合国家标准<0.125 mm/a的要求。现场应用表明,运行1年后,再检时未发现明显腐蚀现象,防护效果良好。     

Effect of air gap on gas permeance/selectivity performance of BTDA‐TDI/MDI copolyimide hollow fiber membranes

Fabrication, morphology evaluation , and permeance/selectivity properties of three asymmetric BTDA‐TDI/MDI copolyimide hollow fiber membranes (HFM s ) are reported. The asymmetric HFM s were spun using the dry/wet phase inversion process. The effect of one of the major spinning parameters, the air gap, on the permeance/selectivity properties of the produced HFM was investigated. Scanning e lectron m icroscopy was used to evaluate the morphological characteristics and the macroscopic structure of the developed HFM. The permeance values of He, H₂, CH₄, CO₂, O₂, and N₂ gases were measured by the variable pressure method at different feed pressures and temperatures and the permselectivity coefficients were calculated. The higher selectivity values were evaluated for the Μ1 membrane and were found to be 49.33, 2.99, 5.13, 5.57 , and 9.61 for H₂/CH₄, O₂/N₂, CO₂/CH₄, CO₂/N₂ , and H₂/CO₂ gas mixtures , respectively. The selectivity experiments of H₂/CH₄, CO₂/CH₄ , and O₂/N₂ mixtures were performed at 25 ° C. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4490–4499, 2013     

Study of sacrificial anode cathodic protection of buried tanks: Numerical modelling

A finite element numerical model was set up to calculate the secondary distribution of potential and current density at the surface of a buried tank. The steel gas tank of interest was protected by both coating and two sacrificial anodes (magnesium alloy or zinc). The dispersion of actual soil properties was taken into account by use of three typical soils. The comparison of two dimensional and three-dimensional models shows that the 2D model is obviously both convenient and time saving. The numerical model allows the calculation of the cathodic protection current and of the local potential in every point of the tank. The model intends to compare the relative influence of coating quality, electric conductivity of soil and position, size and type of the sacrificial anodes (magnesium or zinc). Soil conductivity and coating porosity appear as the two most influential parameters. This model justifies the interest of the tank experimental potential and current measurements.List of symbols