煤气管道带压开孔作业的安全技术保障

鞍山钢铁集团公司(以下简称鞍钢)拥有高炉、转炉、焦炉几十座,煤气管路千余条,总长度可达300 km,遍布鞍钢每个角落,最大直径是西区新2#高炉煤气管道,直径3 500 mm.最长煤气管道是由厂区新1#高炉到灵山厚板厂输送,全长7 km. 如此众多的管道,不可避免要进行管道的维护和保养,特别是要进行煤气管道的改造,即开孔作业.常规的作业方法是:首先在开孔作业管道下方搭设检修作业平台,作业平台须满足相关安全技术要求,其次停煤气,将要进行改造即开孔作业的煤气管道压力为零.     

聚氨酯-水泥带压注水封孔测压技术研究

基于传统上向钻孔测压技术的分析,提出一种新型上向孔测压技术—聚氨酯—水泥带压注水封孔测压技术。该技术利用气体渗透性大于液体的弱点,变传统封堵漏气通道为封堵液体泄漏通道,降低封堵漏气难易程度,提高测压成功率;同时利用水作为动力介质和辅助封孔材料,实现主动测压和钻孔带压注浆,隔绝钻孔瓦斯与外界环境的直接接触,提高系统本身测压的可靠性。通过理论分析及与常用测压技术对比表明,该技术用于煤层瓦斯压力测定是完全可行的。     

一起丙烯罐式汽车泄漏带压堵漏实例析

2004年6月26日在吉林市合肥路公铁立交桥下发生一起严重的丙烯罐式汽车泄漏事故,《丙烯罐式汽车泄漏带压堵漏实例》Ⅲ比较详尽地介绍了该事故的经过及处理事故所采用的带压堵漏技术。本文通过对该实例的分析,认为该实例既有非常成功的经验值得借鉴,也有不足之处或是需进一步改进的地方,以便在类似事故再次发生时,能迅速采取最有效的安全措施和技术手段,在最短的时间内,将泄漏堵住,把事故的损失和影响控制在最小范围内,以确保人民生命和财产的安全。     

带压注浆封孔技术在汪家寨煤矿的应用

为改进汪家寨煤矿的瓦斯抽采钻孔封孔技术,提高封孔质量,针对目前封孔工艺存在的问题,提出以新型无机封孔材料、封孔器为一体的"两堵一注"带压注浆封孔技术。现场的应用试验表明,考察期内试验钻孔平均瓦斯体积分数达到了60%以上,有效提高试验钻孔的封孔质量,为下一步的封孔工艺优化改进提供了参考及建议。     

开孔组合型爆破片

爆破片是压力容器的一种安全附件。作为泄压装置,它具有动作灵敏可靠、耐腐蚀、密封性能好、适应性强等优点。爆破片主要用于介质易燃爆,粘度大、腐蚀性强、反应过程不稳定、安全阀不能胜任的场合。 开孔组合型爆破片属于拉伸类型。它由一个开有通孔及狭缝的金属预拱膜片和一层     

工程常用开孔补强方法的原理探讨及对比分析

压力容器壳体开孔区应力性质和加载方式的不同对壳体强度破坏的形式不同,因此对强度校核需对应采用不同的开孔补强方法。本文基于工程实际,从理论原理和设计准则方面分别探讨了各种开孔补强方法的适用性、合理性及局限性,以期为工程设计人员提供一定的理论指导:等面积法和压力面积法均只考虑薄膜应力的一次静力强度问题,对小开孔补强计算具有一定的可靠性,对大开孔补强计算则均不适用或不可靠;有限元法在大开孔补强中对薄膜应力和薄膜+弯曲应力的评定均比分析法严格;ASME弯矩法对小开孔补强计算具有较高的可靠性,对大开孔补强计算因未考虑绕接管母线方向弯矩的作用而不可靠;有限元法则因无法区分一次和二次弯曲应力,导致对一次应力评定较为保守,而对二次应力评定则偏冒进。     

煤气管道带气抽堵盲板、开孔接管中的安全技术

生产或使用煤气的工业企业常常需要带气抽堵盲板和开孔接管作业。此类特殊作业存在中毒、着火、爆炸的危险性，为了安全、高效地实施此类作业，本文结合企业15年安全作业的实践，系统地总结了作业的方案制定、主要准备工作、作业过程的控制等方面措施和内容，并总结了相关安全技术问题的一些做法和体会。     

泄压 带压堵漏的安全技术

带压堵漏和降压、泄压堵漏是许多行业普遍采用的一门技术。有些特殊情况 ,带压堵漏涉及高温高压、易燃易爆、有毒或剧毒等工况 ,若方法不当 ,措施不良、技术不佳或责任心不强 ,不但堵不了漏 ,反而会扩大泄漏 ,危及生产和人身安全。一、堵漏中应注意的安全问题１.避免燃烧常见的可燃物有氢气、一氧化碳、氨、甲烷、乙烷、丙烷、乙烯、丙烯、丁烯、丁二烯、乙炔、石油气、天然气、水煤气、煤气、汽油、煤油、石油醚、柴油、溶剂油、工业润滑油、二硫化碳、乙醚、丙酮、苯、甲笨、乙苯、甲醇、乙醇、石脑油等。在堵漏时如果这些物质是介质或与…     

木工平压刨床消声孔

四川都江木工机床厂最近制成一台MB904有消声措施的木工平压刨床。消声措施是:在靠平刨刀轴附近的前后工作台,各钻三排φ10毫米的小孔;第一排21个,第二排20个,第三排19个。孔呈三角形排列,对称均匀分布,穿孔率22%。在刀轴转速5,000转/分时产生的高速气流,通过工作台的孔降低气流速度,减弱了噪声的传播。 经测定,距机床1,000毫米、高1,500毫米处,将前后工作台的孔全部挡住,噪声98分贝(A),不挡则为83分贝(A),降低了15分贝(A)。(见附图)。木工平压刨床消声孔@张宏江     

实用带压堵漏技术

通过对带压堵漏技术的特点、技术要求、工序和安全防护的介绍,使更多的企业能运用带压堵漏技术,消除石化企业生产过程中的安全隐患。     

One-step estimation method and nomogram to predict safety distances of pressurized gas pipelines from blast sources

Pressurized gas pipelines may be endangered by accidental or intentional activities causing excess ground vibrations leading to failure. Thus, many papers have been published on this issue, yet most of these efforts suffer from complexity and inability to ascertain that all engaged factors are taken into account. These factors are attributed, namely, to explosion source, explosion-ground interaction, energy transfer through the ground, ground-pipeline interaction, and response of the pipeline. The deterministic method developed previously by the author has derived useful prediction mathematical formulas that can be used to calculate, either the stand-off distance of purposefully used explosives, or the maximum quantity of explosives to be used at a given distance, or the equivalent stress of a pipeline induced by an explosive charge at a given standoff distance. The method can also be applied to accidental blast events in factories or other activities. Yet, the complex formulas developed are hard to be used in the field and a simpler approach is needed to facilitate and accelerate in-field estimations. Thus, a nomogram was prepared to make the safety estimations easy and fast and taking into account all engaged critical factors starting from the explosion source through the integrity of the structure.     

Numerical simulation of water curtain application for ammonia release dispersion

Using water curtain system to forced mitigate ammonia vapor cloud has been proven to be an effective measure. Currently, no engineering guidelines for designing an effective water curtain system are available, due to lack of understanding of complex interactions between ammonia vapor cloud and water droplets, especially the understanding of ammonia absorption into water droplets. This paper presents numerical calculations to reproduce the continuous ammonia release dispersion with and without the mitigating influence of a downwind water curtain using computational fluid dynamic (CFD) software ANSYS Fluent 14.0. The turbulence models k–ɛ and RNG were used to simulate the ammonia cloud dispersion without downwind water curtain. The simulated results were compared with literature using the statistical performance indicators. The RNG model represents better agreement with the experimental data and the k–ɛ model generates a slightly lesser result. The RNG model coupled with Lagrangian discrete phase model (DPM) was used to simulate the dilution effectiveness of the water curtain system. The ammonia absorption was taken into account by means of user-defined functions (UDF). The simulated effectiveness of water curtains has good agreements with the experimental results. The effectiveness of water mitigation system with and without the ammonia absorption was compared. The results display that the effectiveness mainly depends on the strong air entrainment enhanced by water droplets movement and the ammonia absorption also enhances the effectiveness of water curtain mitigation system. The study indicates that the CFD code can be satisfactorily applied in design criteria for an effective mitigation system.     

起伏管道积水运动特征实验研究*

为研究油流携水过程中的积水运动特性,明确排除积水临界条件。以0#柴油、自来水为实验介质,利用内径（D）为50,80 mm,上倾倾角（β）为1°,5°,10°的水平-上倾实验环道,对表观油速（Uos）为0.25 m/s、无量纲水相高度（h/D）在0.5范围内,油流剪切作用下的管道积水运动特征进行实验。研究结果表明:积水流型随表观油速、无量纲水相高度、上倾倾角的增大由光滑分层流逐渐向波状分层流、液滴分层流过渡,其中表观油速影响最为显著;积水爬坡距离随表观油速增加而显著增加,随上倾倾角增大而减小,随无量纲水相高度减小而减小;实验说明弗劳德相似准则能较为准确地预测起伏管道中积水携带临界表观油速;由弗劳德相似准则预测可知,内径为489 mm管道积水排除的临界表观油速约为1.60 m/s,研究结果对减少管道内腐蚀有一定指导意义。     

Numerical simulation of ammonia dispersion around a water curtain

Water curtains have been suggested as a way of limiting the spread of ammonia in the event of an accidental release. Several field experiments have already been performed to investigate the interaction between a water curtain and a cloud of ammonia, most recently by Bara and Dusserre (1997, J. Loss Prev. Ind., 10(3), 179–183). Those experiments have been modelled numerically, using the computational code Mercure. The calculated velocities and concentrations agree reasonably well with the measurements.     

A modified steady-state model for evaluation of ammonia concentrations behind a water curtain

Water curtain system has been proved an effective mitigation measurement for ammonia spill dispersion. Calculating of ammonia cloud concentration with water curtain was less studied. This paper presents a steady-state calculation model to calculate open and forced ammonia spill dispersion. The formula of ammonia absorption was built and integrated into the calculation model. The calculated downwind ammonia concentrations for open and forced spill dispersion were reproduced and compared with literature using a statistical method. In addition, the relationship between ammonia concentration in water droplet and the droplet diameter was studied. The results display that the formula of ammonia absorption is suitable for calculating mass transfer process between the ammonia cloud and the water curtain. The calculation model presents good performances for open and forced ammonia spill dispersion. This study indicates that the calculation model can be satisfactory in determining the impact of open and forced ammonia spill dispersion and the design of water curtain mitigation system.     

水体监测中氨氮测定的影响因素分析

目前,水质监测的范围非常广泛,通常包括易受污染水体和未受污染水体的监测。一般在水质监测过程中,首先需要确定的是科学合理的检测方法,然后对影响该检测方法精度的因素进行综合分析并进行有效监测,当今水质监测中氨氮浓度是评价水质好坏的重要指标之一。基于此,文章综合分析了水体中氨氮浓度检测的基本原理并重点探讨了水体监测中影响氨氮测定的主要因素。     

Integrated-signal-based leak location method for liquid pipelines

Leaks in pipelines can cause major incidents resulting in both human injuries and financial losses. Among the considerable leak detection and location methods, the Negative Pressure Wave (NPW) based method has been widely used in locating leaks in liquid pipelines. The NPW based method only monitors the pressure changes at two ends of a pipeline. But the pressure is apt to be fixed by the end equipment and the change of it induced by a small or slow leakage is too small to be detected, which limit the application of the NPW based method in these situations. This paper presents a novel leak location method based on integrated signal, which is a combination of the pressure and flow rate signals. The representation of the integrated signal is derived from the transient analysis of the leakage. For the change of the integrated signal induced by a leakage is larger than the pressure change and it is also unaffected by the end equipment, the proposed method can be used to detect and locate small or slow leakage in a pipeline and can also be used in pipelines which end pressures are fixed by some kinds of equipment. The validation of the proposed method also confirms its advantages.     

絮凝沉淀法测定地表水中氨氮的方法改进

本文通过比较监测黑臭河流氨氮时人员比对的结果,对絮凝沉淀预处理过程的关键因素进行了改进。结果表明,直接在离心管中絮凝沉淀、离心、取样分析,精密度和准确度更好,而且方便快捷,值得推广。     

Residual bending capacity for pipelines with corrosion defects

Residual bending capacity for corroded pipelines in the presence of axial force and internal pressure can be determined analytically assuming a full plastic failure mode for the pipeline. In this paper, a set of closed-form analytical solutions for residual bending capacity are developed for pipelines with idealized corrosion geometries, namely, constant-depth, elliptical, and parabolic corrosions. It is shown that pipelines with idealized elliptical or parabolic corrosion yield higher bending resistance than that of constant-depth, with the difference between elliptical or parabolic corrosion particularly significant for the case of deep and wide corrosion. It is further pointed out that the simplification of the actual corrosion geometry by constant-depth, as commonly assumed in current code assessment of corroded pipelines, will inevitably underestimate the residual strength of the pipe, especially for the case of deep and wide corrosion. Finally, the experimentally measured bending moment is adopted to validate the proposed analytical solutions in this paper.     

Gas leakage consequence modeling for buried gas pipelines

One of conservation transfer methods for such widely-used gases as natural gas and hydrogen is buried pipelines. Safety of these pipelines is of great importance due to potential risks posed by inefficiencies of the pipelines. Therefore, an accurate understanding of release and movement characteristics of the leaked gas, i.e. distribution and speed within soil, the release to the ground surface, the movement of hydrogen gas through the ground, gas underground diffusion, gas dispersion in atmosphere, and following consequences, are very important in order to determine underground dispersion risks. In the present study, consequences of gas leakage within soil were evaluated in two sub-models, i.e. near-field and far-field, and a comprehensive model was proposed in order to ensure safety of buried gas supply pipelines. Near-field model which is related to soil and ground and its output is the gas released at different points and times from ground surface and it was adopted as input of far-field sub-model which is dispersion model in atmosphere or an open space under the surface. Validation of near-field sub-model was performed by the experimental data obtained by Okamoto et al. (2014) on full-scale hydrogen leakage and then, possible scenarios for far-field sub-model were determined.