高压变频器在榆中钢厂焦化除尘风机的应用

本文结合焦化除尘风机的生产工艺,综述了高压变频器的性能特点及系统原理,同时详细说明了整体方案,介绍了变频器的节电效果。     

干燥系统中的旋风分离器及半干法旋风除尘技术

比较了国内外常用的旋风分离器的结构尺寸和性能差别。利用干燥尾气中的水分,适当冷却尾气使相对湿度日在38％-45％的范围内,促使粉尘团聚成较大颗粒,从而使旋风分离器尾气排放中的小颗粒（dc≤3μm）的数量下降,提高了除尘效率,且除尘后的颗粒是干态的。半干法除尘比湿法除尘能节约用水和循环水的电能,同时可以避免在循环水中生物质的发酵变质。     

烟草除尘过程中节能减排优化研究

使用全面试验法,对除尘风机的空转时间进行研究,分析了风机空转的原因,并通过增加"制丝需求启动信号"逻辑控制建立了切丝工序与除尘风机的联动程序。本研究对企业产生了一定的经济效益,并可为同领域其他方面的节能减排提供参考和方法。     

Hybrid H2/Ti dust explosion hazards during the production of metal hydride TiH2 in a closed vessel

The explosibility of hybrid H₂/Ti dust in the production of metal hydride TiH₂ was simulated and studied using a 20-L spherical vessel. The influential factors for the explosion performance of hybrid H₂/Ti dust, including particle size distribution and polydispersity, humidity, temperature, hydrogen content, inert gas and degree of reaction, on hybrid explosion were investigated. Results showed that both the mean particle sizes and particle size polydispersity had significant effects on the dust severity of hybrid H₂/Ti dust. The explosion severity of hybrid H₂/Ti dust was enhanced at a higher temperature in a certain range, and it presented a trend of increasing at the early stage and then decreased both for the increasing humidity and hydrogen pressure. Explosion inhibition effects of typical inert gases for hybrid H₂/Ti dust increased in the following order: argon < helium < nitrogen. The values of (dP/dt)_ex and V_f decreased along with the reaction process, while the value of P_ex kept stable, which showed that the hydrogen state had no obvious impact on P_ex but significantly affected the explosion risk of hybrid H₂/Ti dust, and special attention should be paid to the initial stages of the production process of TiH₂.     

接地极雾化电晕放电除尘器的研究

随着经济的快速发展和排放标准的日益严格,粉尘的去除一直是研究的热点。设计了一种新型的接地极雾化电晕除尘器。该除尘器在放电过程中,对颗粒物荷电的同时使线电极表面液体雾化,从而有效去除粉尘。在试验过程中,首先设定进气的气流速度为1 m/s和3 m/s,改变线电极表面覆盖液体流量及气流方向,研究了接地极雾化负电晕放电伏⁃安特性。其次,设定线电极表面覆盖液体流量为25 mL/min,研究了接地极雾化负电晕放电装置中顺向气流和逆向气流下气流速度对除尘效率的影响。最后,为了研究接地极雾化电晕放电除尘器对高比电阻粉尘的除尘能力,在气流速度为1 m/s的逆向气流中,将比电阻为1.2×1012 Ω·m的水泥粉尘作为高比电阻粉尘进行了试验。结果表明,随着气流速度的增加,除尘效率降低。当气流速度较大的条件下,气流逆向流动时的放电电流比顺向流动时大;在线电极表面覆盖液体流量为25 mL/min时,接地极雾化负电晕放电的电流最大。接地极雾化电晕放电除尘器最优条件为：线电极表面覆盖液体流量为25 mL/min,逆向气流速度为1 m/s。相对于传统的干式电晕放电反应器,接地极雾化电晕放电除尘器对高比电阻粉尘具有更高的除尘效率。     

A study on the dust control effect of the dust extraction system in TBM construction tunnels based on CFD computer simulation technology

In order to control dust in a tunnel boring machine (TBM) construction tunnels, this paper, in combination with field measurements, applies CFD computer simulation technology to study the dust control effect of TBM construction tunnels under different dust extraction flow rates. Firstly, the dust extraction system is closed, and the result of the simulation show that the dust diffuses to the entire TBM working area within 181 s, indicating the necessity of having a dust extraction system in the tunnel. Secondly, the dust extraction system is open and under the original dust extraction flow rate of Q_e = 8 m³/s, the overall dust diffuses to the entire working area L_o = 130 m, and the full-face dust diffusion distance is L_f = 47.54 m. Then the study was carried out with the setting of 2 m³/s ≤ Q_e ≤ 14 m³/s. The results show that: when Q_e ≤ 8 m³/s, the full-face dust diffuses to 47.54–71.84 m; when Q_e > 8 m³/s, the full-face dust can be controlled at 42.81–46.34 m; and when Q_e = 8 m³/s, the full-face dust control effect is better, and the average dust concentration in the tunnel is as low as 12.25 mg/m³, indicating that the original dust extraction system has a better design. The field measurement results verify that the CFD computer simulation results are accurate.     

Improved design of dust test chamber for uniform distribution of dust sedimentation rate

Soiling problems are always encountered for equipment installed in outdoor environments, such as headlamps of automobiles, air conditioners, solar collectors, and so on. How to prevent soiling problems on this equipment is one of the challenges for the design of their external layouts. Thus, evaluations of the dust sedimentation quantities on the surfaces of such equipment are necessary. Outdoor testing is usually straightforward but it takes a long time to experience various environmental parameters, such as dust-laden air, wind speed, wind direction, and so on. Indoor tests, performed in a dust test chamber, are instruments for controlling various environmental parameters independently. The conventional design for a dust test chamber is aimed at providing for a test under extreme environmental conditions. The uniformity of dust sedimentation rate within the chamber is not rigorously controlled. Nevertheless, some applications such as the effect of dust sedimentation on the glazing of solar collector require uniform distribution of dustfall in the test chamber for the indoor (laboratory) test. An improved design for a conventional dust test chamber is proposed. Performance tests done with the remodeled dust test chamber based on the improved design show that the normalized standard deviation of the dustfall concentration can be controlled within 2.41% ± 1.29%.     

Preparation of fused silica membrane with high performance for high temperature gas filtration by sealing and spray coating

In order to improve the gas permeability and thermal shock resistance of the ceramic membranes applied in high temperature gas-solid separation techniques, fused silica and graphite particles were used as the primary raw material and pore-former agent, and the spray coating based-on PVA sealing was applied to prepare the separation membrane. These approaches remarkably decreases filtration resistance by increasing support permeability and reducing the intrusion of ceramic membrane forming particles into the support as well as the thickness of the membrane. The fabricated membrane had an average pore diameter of 9.85?μm and a gas permeability value of 8.2?×?10⁴?m³/(m² h bar), its dust removal efficiency reached 98.6%.     

排尘口直径对旋风分离器壁面磨损影响的数值模拟

基于计算流体动力学(Computational fluid dynamic,CFD)的数值模拟方法,在FLUENT软件平台上,应用雷诺应力模型、离散相模型和磨损值计算模型系统地研究排尘口直径对旋风分离器壁面磨损的影响。计算结果表明,旋风分离器壁面磨损的整体变化趋势不随排尘口直径的改变而变化,都呈现局部磨损的形态。排尘口直径减小,环形空间壁面磨损值保持不变,分离空间壁面磨损值有不同程度的增加,在锥体末端附近增加幅度最大,而这种变化主要是由于排尘口直径变化后分离器内部流动结构的变化引起的。分离空间锥体末端附近壁面的严重磨损主要受气固两相的旋转速度、颗粒浓度、旋进涡核和颗粒受力情况的影响。通过研究揭示合理地进行结构设计在减少磨损中的重要作用,为旋风分离器壁面的防磨提供数值试验方法和依据。     

炼铁厂出铁口烟尘综合利用的研究

本文分析了炼铁厂出铁口烟尘的性质,并用选矿方法对烟尘进行提纯,通过重选、磁选、浮选的试验研究,结果表明;“分级一磁选”效果最好,可获得铁品位为68．78％的超级铁精矿,回收率为66．22％;另一铁精矿品位为57．93％,回收率为32．86％;尾矿铁损失率仅为0．92％。文章还对后续深加工提出了具体建议。