热烧结矿竖式冷却过程传热特性

 与传统环冷相比,烧结竖冷拥有漏风率低、换热效率高的优势。为此利用竖冷试验装置,在某烧结厂取热风与热烧结矿研究了竖式冷却过程气固对流换热特性。研究表明,烧结矿竖式冷却过程中影响传热特性的主要因素为冷却风的流量及温度。烧结矿和冷却风对流换热系数随着烧结矿温度的升高而增大,且随着冷却风流量的增大以及冷却风温度的降低,对流换热系数也随之增大。基于白金汉定理,结合试验数据拟合得出了描述烧结矿与冷却风传热特性的准数关联式,其模拟性较好且平均相对误差为7.25%。     

进风井石门巷两道三分法工程在三山岛金矿的应用

随着近地表资源的日益枯竭,矿山地下开采由浅部区域进入深部区域已成为发展趋势,通风系统的完善程度直接制约矿山向深部发展。针对三山岛金矿采掘作业面通风紊乱,通风环境恶化的问题,通过采用进风井石门巷两道三分法工程,建立风门、风窗对新鲜风流合理疏导、调节,达到定向、定量输送新鲜风通往深部的目的。该工程的应用不仅保证了现有生产、掘进的需风量,同时增加了深部进风量,并通过风门、封闭墙实现人车分流、调控分风等功能,具有一定的先进性,可为同类型矿山提供借鉴。     

Modeling Immune Building Systems for Bioterrorism Defense

This paper presents the results of research on the performance of air-cleaning and air-disinfection systems used for protecting buildings against intentional releases of biological agents. The air-cleaning technologies addressed include dilution ventilation, filtration, and ultraviolet germicidal irradiation. A 40-story commercial office building is modeled using typical occupancy levels and leakage rates for doors, walls, and floors. A steady-state single-zone model is used to predict steady-state conditions resulting from the use of various levels of air cleaning. A transient single-zone model is used to predict transient indoor concentrations from which inhaled doses and estimated casualties are predicted. A transient multizone model is used to evaluate contaminant dispersion and estimate potential casualties. Three design-basis attack scenarios are simulated using various biological weapon agents. Predicted casualties are estimated using an epidemiological model of the dose response curves for each of the agents. The effect of increasing levels of air cleaning is examined under the attack scenarios to evaluate their effectiveness. Results indicate that high levels of protection are possible for building occupants with moderate and affordable levels of air cleaning when filtration is combined with ultraviolet germicidal irradiation. Results also suggest that diminishing returns occur when increased levels of air cleaning are applied. It is hypothesized that the maximum useful size of any air-cleaning system is defined and limited by building physical characteristics alone.     

卡罗塞尔卷取机大转盘力学性能分析

文章利用三维建模软件对结构复杂的卡罗塞尔卷取机大转盘进行了建模。在此基础上,利用有限元分析软件ANSYS对大转盘进行了最恶劣工况下的力学分析,直观展现了大转盘存在的应力、应变,为掌握卡罗塞尔卷取机的力学性能提供了可靠的理论分析依据。     

Selective exclusion of the injured lung

Intratracheal bleeding and intrapleural air leakage that are uncontrollable by conventional therapy are life-threatening in patients with blunt pulmonary trauma. Selective exclusion of the injured lung is the most effective treatment in such cases. Two hundred six consecutive patients over a 5-year period with blunt pulmonary trauma who survived 5 hours or more after arriving at the hospital were divided into three categories based on mode of treatment. In 190 (92%), intratracheal bleeding, intrapleural air leakage, and intrapleural bleeding were controllable by conventional treatment (class 1). In six (3%), intratracheal bleeding and intrapleural air leakage were controllable by selective pulmonary exclusion, and intrapleural bleeding was controllable by tube thoracostomy (class 2). In ten (5%), thoracotomy was required because of uncontrollable intratracheal bleeding or intrapleural air leakage, despite selective pulmonary exclusion, or intrapleural hemorrhage was not controllable by tube thoracostomy (class 3). Among the 16 patients with class 2 or 3 trauma, 14 survived.     

烧结机缝隙磁场密封模拟实验

为解决钢铁厂烧结机高漏风率问题,设计制作了缝隙磁场密封模拟装置,用钕铁硼永磁合金作为密封磁场源,模拟烧结机的缝隙状况进行了磁场密封实验。结果表明:在磁力作用下,密封介质被约束在缝隙中,形成了均匀致密的密封屏障,在15～300℃温度下,密封负压达到50 kPa。本磁场密封方法用于实际烧结机中,足以使所密封部位达到"0"漏风率。     

高炉软水冷却系统水流特性研究

高炉软水密闭循环冷却系统水流特性实验室试验研究表明：当支管破损产生泄漏时,该支管入口水量增加,出口水量减少,且泄漏量与入口水增量或出口水减量成线性关系;当高炉休风时,泄漏量剧增;当高炉局部过热,支管内水汽化,体积膨胀,流动阻力增加,该管水量减少,致使汽化更甚,直到形成“汽塞”烧坏为止。     

Measurement Techniques for Estimating Local and Total Duct Leakages in Residential Buildings

The paper proposes two measurement techniques for estimating the duct leakage in residential buildings. The first technique determines the “local” leakages using commercially available zone bags and it is called the zone bag-based measurement technique. Zone bags are used to block the flow of air in ducts so that portions of the duct can be isolated and pressurized separately to measure the respective leakages. The thrust of this technique is to locate where these potential leaks are in the duct system and try to provide more cost effective ways to remedy those leaks than what is available currently. The other technique determines the “total” supply and return leakages using a simple model and it is called the model-based measurement technique. The model is based on pressure drop measurements between the return and supply sides. The proposed techniques were evaluated and validated at the air duct leakage laboratory which has two different air duct configurations and a wide range of leakage levels controlled by holes created at several locations of ductwork. Experimental results indicate that the zone bag-based measurement technique estimates the local leakage accurately with a mean absolute difference of 0.26% of total air-handler flow compared to the baseline. It can be inferred that this method gives a better estimate of the total leakage based on the location of the leak than the duct pressurization method that uses the half plenum pressure technique. The results also show that the model-based measurement technique is a good alternative when one cannot use a physical barrier between the return and supply sides. It was found that the total supply or return side leakage was estimated with a mean absolute difference of 0.6% compared to the baseline technique. The future research step is field testing techniques to examine how one can more efficiently sample the duct system by judicially sectioning off the duct at a few points to obtain localized leakage information and obtain enough information to correct leak problems.     

远程控制自动风门在曹家洼金矿的应用

曹家洼金矿井下的主要进风巷、主回风巷绝大部分都是井下运输的主要通道。因井下通风的需要,需在这些巷道设置风门,进行风量调节、阻断风流。以远程控制自动风门为研究载体,从安全、生产、设备方面进行探索,重点分析远程控制自动风门在曹家洼金矿开采中的应用。生产实践表明:该远程控制自动风门系统降低了作业强度,降低了生产成本,提高了安全性,可为同类型矿山提供借鉴经验。     

高炉无料钟炉顶均排压系统旋风除尘器漏气分析及优化设计

针对某铁厂大型高炉无料钟炉顶放散系统旋风除尘器局部产生漏气问题,采用ANSYS有限元法对漏气部位的应力分布进行分析,表明最大应力出现在矩形直段大侧面直角边处,也是实际漏气部位,属材料疲劳破坏造成.以此为依据,对旋风除尘器进行结构优化设计,成功应用于实际,取得良好效果,具有重要的实际推广应用价值.     

3D CFD Predictions and Experimental Comparisons of Pressure Drop in a Ball Valve at Different Partial Openings in Turbulent Flow

A three dimensional computational fluid dynamics model, using the STAR-CD software, has been developed to simulate fluid flow in a commonly used flanged ball valve at different partially open settings. The Reynolds number (Re) range for the flow simulations was varied between 105 and 106 to simulate a variety of flow conditions. Each flow Re number is studied with three open positions for the valve, i.e., fully open, two-thirds open, and one-third open. The simulation was used to calculate two important parameters used in characterizing the flow properties in a typical valve namely the loss coefficient, K, and the flow coefficient, Cv. An attempt was also made to compare some of the simulation results with experimental data and available American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) data on valves. The simulations agree reasonably well with recently published experimental results and indicate that in most cases the K factor is independent of Re. The ASHRAE data for K factor values showed similar trends to the simulation but with lower values as it was only reported for gates valves. The Cv values show strong increases with the degree of valve opening and lesser influence by the Re number variations in the range studied     

转炉冷却烟道泄漏故障分析

针对武钢三炼钢厂的转炉烟气冷却系统汽化器的漏水故障,对系统实际运行参数进行了实测,并根据测得的数据进行高精度热力校核计算。基于校核结果的进一步分析和测试表明,腐蚀疲劳是汽化器漏水故障的主要原因。     

Emissions at Coke Plants: European Environmental Regulations and Measures for Emission Control

At coke plants several pollutants are formed during coking, which are released to ambient air. To protect human health and to avoid harmful impacts on ambient air quality effective control of coke oven emissions is most significant. At coke plants the main source of emissions of NOx, SO₂ and particulate matter is the flue gas from combustion of cleaned coke oven gas in the battery underfiring. Hence, advanced processes for coke oven gas cleaning in the by-product plant, like scrubbing processes for desulfurization of coke oven gas, are important measures at coke plants to reduce emissions to air. Effective filter equipments are available to abate emissions of dust from coke pushing and coal charging. Fugitive emissions at the batteries from leaking oven doors, lids and ascension pipes as well as fugitive emissions in the by-product plant from leaking pipes, flanges and valves can be abated by effective sealings, smooth operation and regular maintenance of all equipments. Inside the European Union emissions at coke plants are regulated in EU-directives on basis of Best Available Techniques (BAT) and monitored regularly by stipulation of national and local authorities. This paper focuses on (1) Legal EU-regulations on abatement of coke oven emissions into air, (2) Modern emission control measures available nowadays at coke plants.     

The effect of inclusions of aluminum oxide on the processes of hydrogen dissolution and evolution in aluminum and copper melts

From the analysis of publications, it is concluded that the assumption about the effect of nitrogen bubbles on the film inclusions of aluminum oxide formed during the contact of aluminum melts with air as the ready centers of hydrogen evolution in the form of bubbles from the solution-melt previously put forward by the authors is valid. Based on this notion, the results of many production and laboratory investigations on the relation between the contamination of aluminum melts by oxide inclusions and porosity of cast billets caused by the evolution of hydrogen bubbles is logically explained. This notion is valid for brasses and bronzes, which include aluminum as an alloying component or in the form of impurity. The direct experiments for water containing dissolved air or carbon dioxide vividly demonstrated the effect of the mentioned mechanism. The uselessness of the term “bifilm” to describe double oxide films and the inadmissibility of its use in metallurgical publications in Russian are noted.     

含砷铁矿石烧结及除尘灰焙烧脱砷热力学

 为了研究铁矿石烧结及除尘灰焙烧脱砷问题,运用FactSage软件研究了不同氧分压、温度及碱度对含砷铁矿石烧结脱砷率、砷平衡组成、脱砷最终形态的影响,并对除尘灰焙烧脱砷流程进行热力学研究。结合烧结杯进行烧结试验,并在多气氛下利用焙烧除尘灰试验进行验证,运用XRD、SEM及EDS对矿相进行分析。结果表明,脱砷产物及脱砷率与温度、氧分压及碱度密切相关。在烧结过程中,残留在烧结矿中的砷,主要是固态砷酸盐,其他砷会以As4O6（g）等气态物质脱除。除尘灰中砷以固态As2O3（s）和As2O5（s）存在。在空气或厌氧气氛下焙烧除尘灰,会使砷转变为砷酸盐。但采用配比煤粉及厌氧条件下,在600 ℃以上焙烧除尘灰,可使砷以气态As4（g）挥发,在400 ℃以下析出单质砷。     

Complications of rectal anastomoses with end-to-end anastomosis (EEA) stapling instrument. Clinical and radiological leak rates and some practical hints

The complications and results of rectal anastomoses carried out with the end-to-end anastomosis (EEA) stapling instrument on 50 patients by 5 consultant surgeons are recorded. There was a clinical leakage rate of 6% and a radiological leakage rate of 20% assessed by water-soluble contrast enema. The technique has advantages compared with hand-suture by allowing low anastomoses and preservation of sphincters and is accompanied by an acceptably low leakage rate. Despite the cost of disposable cartridges these advantages make the technique economical because of the avoidance of colostomies and reduction in hospital stay.     

超声波重油喷嘴雾化特性的研究

介绍了一种新型流体动力式超声波重油雾化喷嘴。为了研究其雾化特性,以压缩空气和水为介质,利用激光粒度分析仪对超声波重油雾化喷嘴的雾化特性进行了详细的研究,分析了该型喷嘴的工作特点,研究了不同供气压力、供水压力和气液比(ALR)对喷嘴雾化性能的影响,同时也分析了粒径沿程变化情况。研究表明:流体动力式超声波重油雾化喷嘴雾化索太尔平均粒径非常小,为10～20μm,具有较好的应用前景。     

长筒球磨机简体结构改造

通过对包钢选矿厂Φ3.6 m×6.0 m的长筒球磨机筒体,进行了受扭矩和重力作用的分析,并进行简支梁的扭矩和受力计算。结合实际运行情况,把筒体上原为两个人孔门结构,改造为一个人孔门结构。经过对人孔结构改造,减少了人孔门处裂漏所矿导致的很多故障,创造了可观的经济效益。     

燃气焙烧启动技术在石墨化阴极电解槽的工业应用与分析

燃气焙烧启动技术和石墨化阴极技术是当前电解铝企业面对国家阶梯电价政策要求下全面降低电能消耗的首选技术。通过分析燃气焙烧启动技术优势和石墨化阴极特性,指出了石墨化阴极电解槽采用燃气焙烧时需要提高焙烧温度、调整升温策略和延长焙烧时间等技术措施,并在2台400 kA电解槽上进行了工业应用,达到了启动后无渗漏现象,在平稳运行6个月的时间内,炉底压降可以稳定保持在185 mV以下,吨铝直流电耗为12 269 kWh,达到了行业较好水平。     

浅议烧结机的漏风及对策

通过对湘钢一烧 2号烧结机漏风率的测试 ,根据其测试结果 ,通过分析讨论 ,从密封位置、润滑系统、维护与管理等方面提出了一系列降低漏风率的对策 ,为烧结工序的增产节能 ,降低生产成本 ,提高经济效益提供了一条行之有效的途径。