Experimental studies of air-blast atomization on the CO_(2)capture with aqueous alkali solutions

In this work,an air-blast atomizing column was used to study the CO2 capture performance with aqueous MEA(mono-ethanol-amine)and Na OH solutions.The effects of gas flow rate,the liquid to gas ratio(L/G),the CO2 concentration on the CO2 removal efficiency(η)and the volumetric overall mass transfer coefficient(KGav)were investigated.The air-blast atomizing column was also compared with the pressure spray tower on the studies of the CO2 capture performance.For the aqueous MEA and Na OH solutions,the experimental results show that theηdecreases with increasing gas flow rate and CO2 concentration while it increases with increasing L/G.The effects on KGavare more complicated than those forη.When the CO2 concentration is low(3 vol%),KGavincreases with increasing gas flow rate while decreases with increasing L/G.However,when the CO2 concentration is high(9.5 vol%),as the gas flow rate and L/G increases,KGavincreases first and then decreases.The aqueous MEA solution achieves higherηand KGavthan the aqueous Na OH solution.The air-blast atomizing column shows a good performance on CO2 capture.

Response of droplet parameters to liquid viscosity in the flow field of an air-blast sprayer

The physical properties of sprayed droplets such as viscosity affect their deposition on the target.In order to understand the response characteristics of droplet parameters to the viscosity of a spray solution,a three-dimensional model of the external flow field of an air-blast sprayer based on computational fluid dynamics(CFD)was established according to the actual spray range and the sprayer duct structure.The change rules of droplet diameter and droplet density with distance under different viscosities of the spray solution in the flow field were obtained through numerical solution of the CFD model.The reliability of the model was verified by a chi-squared test comparing the numerical calculations with the results of field experiments.The results showed that the change rule of droplet parameters in an airflow field under different values of the spray solution viscosity was consistent.With the increase in the axial distance,the droplet size decreased initially,then increased,and finally decreased,while the droplet density gradually decreased.Moreover,the greater the spray solution viscosity,the shorter the conveying distance of the droplets in the axial direction,although viscosity was helpful in reducing the droplet drift.In addition,at the same axis distance,with the increased viscosity of the spray solution,the droplet size increased,and the sedimentation of the droplets was more rapid,while the density of the droplets decreased.The results provided a new framework for the study of air-blast spraying technology and serve as a reference for the optimization of the sprayer structure and the preparation method for spray solutions.

深孔轴向多段间隔装药孔壁冲击压力分布

为确定地下垂直长深孔爆破时合理的空气间隔长度,基于爆轰波理论,分析了多段间隔装药爆破条件下孔壁冲击压力随间隔长度变化的内在分布规律函数;依据Mises准则,得出了不同岩性时合理的间隔长度参考值,并通过数值模拟和现场爆破试验进行了验证。结果表明,空气间隔段孔壁冲击压力沿炮孔轴线从两端向中间骤降,但在中点周围略微增大,压力曲线呈两端大、中间小、中点周围略微凸起的“W”形对称分布。

Experimental Studies on Fuel Spray Characteristics of Pressure-Swirl Atomizer and Air-Blast Atomizer

In this work,the effects of fuel temperatures and pressure drops on the flow field and spray characteristics of a pressure-swirl atomizer were discussed using the Particle Imaging Velocimetry(PIV),Planar Laser Induced Fluorescence(PLIF)and Laser Particle Size Analyzer(LPSA)methods.Then the air-blast atomizer was selected to study the interaction of initial atomization and flow field.The effect of fuel-air ratio on the air-blast atomizer were also considered,where the fuel-air ratio was varied by adjusting mass flow rate of the air and fuel respectively.The results show that the spray angle of the pressure-swirl atomizer increases first and changes a little after the pressure drop higher than 0.5 MPa.However,more fuel concentrate on the central region,which is mainly caused by the increase of the proportion of small droplets with lower centrifugal force.The fuel temperature can improve the spray angle only in lower pressure drop,and it has a little effect under higher pressure drops.In addition,the fuel pressure drop has an obvious influence on the fuel distribution and flow field near the nozzle exit compared with the downstream.For the air-blast atomizer,the spray angle increases compared with the pressure-swirl atomizer for the introduction of swirl air.Furthermore,the spray angle decreases with the air mass rate increasing,and it increases with the fuel mass rate increasing.The distribution of velocity and droplet near the nozzle exit is influenced by the air mass rate,and the fuel mass rate mainly affects the distribution in the downstream.The fuel accumulates in the annular area below the nozzle,and the distribution of it changes little with the development along the axial direction.

梅蓄电站二期上引水洞爆破开挖诱发空气超压对上库事故闸门的影响分析

爆破开挖过程中产生的空气超压可能会影响周边建构筑物的安全。梅州抽水蓄能电站二期引水平洞的爆破作业区,距离在一期工程中已建好并投入运行的二期工程引水上平洞上库钢质事故闸门仅81 m,爆破作业可能会影响事故闸门的稳定运行。为此,以梅州抽水蓄能电站二期引水上平洞的爆破开挖为对象,开展了爆破空气超压现场监测工作,分析了爆破空气超压的分布规律及其对梅州抽水蓄能电站上库事故闸门的安全影响,为分析爆破空气超压对上库事故闸门的安全影响提供了支撑。现场的爆破空气超压监测数据表明:距离爆破掌子面约80 m的事故闸门前的空气超压水平分布在0.63~3.46 kPa,远小于建议的相应的爆破安全控制标准100 kPa;闸门前使用胶帘等防护设施可以有效减小闸门位置的空气超压,实测的第4次和第5次爆破空气超压减小了55%以上;单段装药量及总装药量得到有效控制时,实测的空气超压值远低于建议的控制标准;现场宏观调查及其他检测数据也未见异常,爆破施工未影响上库事故闸门的安全运行。

质量参数对空爆荷载梁构件振动位移的影响

为研究质量参数对空爆荷载梁构件振动位移的影响,以等效单自由度法为基本方法,理论推导了柔性及刚性2类梁构件含质量参数在弹性、塑性各阶段的振动位移解,选择矩形截面、圆截面为梁构件典型截面,设计并计算了质量参数在1.00~1.20范围内的13种典型工况。结果表明:对于空爆荷载柔性及刚性2类梁构件,增大其截面面积后,仅考虑质量参数计算振动位移时误差较大,应按质量参数及产生的附加刚度参数耦合效应分析;对于矩形截面梁构件,采用质量参数与刚度参数耦合计算时,其最大弹性位移、最大弹塑性位移和残余变形降低幅度分别约为仅采用质量参数计算结果的4.75、3.28和2.96倍;对于圆截面梁构件,则分别为3.57、2.56和2.32倍;该结论在柔性梁构件及刚性梁构件均适用且无明显差异。

基于Workbench的高炉送风装置直吹管有限元分析

文中针对高炉送风装置的直吹管进行了静力学分析和模态分析,研究其结构及振动特性。在静力学分析方面,利用有限元方法建立了直吹管的数值模型,并对其进行分析,以了解筒体的整体变形及等效应力情况。模态分析方面,提取了直吹管前20阶模态的固有频率,并对前6阶的振频、振型和振幅进行了详细分析。研究结果显示,直吹管的固有频率随阶数递增,符合无阻尼振动的特征。此外,前6阶模态的振型和振幅得到了全面解析。通过静力学分析和模态分析,深入了解了高炉送风装置直吹管在静力学和振动方面的特性,为进一步的结构设计和优化提供参考。

装药结构对硬质岩隧洞轮廓成型效果的影响研究

硬质岩隧洞的轮廓成型效果对提高围岩稳定性和降低支护成本具有重要意义。以优化隧洞轮廓孔单孔装药量和装药结构为目标,首先,理论分析了隧洞爆破中轮廓孔装药参数的取值范围;其次,分别以1200 g、900 g、750 g、600 g的单孔装药量进行了硬质岩隧洞爆破试验,并借助激光扫描仪对隧洞轮廓成型效果进行了扫描分析;最后,利用断裂力学模型分析了不同单孔装药量的隧洞轮廓成型效果。结果表明:当硬质岩隧洞的轮廓孔装药参数在合理范围内时,单孔装药量越小,爆破产生的孔间裂缝数量越少,岩体损伤范围也越小;当装药量由1200 g降低至600 g时,隧洞轮廓超挖体积由6.53 m^(3)降低至2.02 m^(3),但由孔位误差导致的轮廓欠挖体积由0.15 m^(3)增大0.26 m^(3);断裂力学模型在硬质岩隧洞轮廓爆破的模拟中优于损伤模型,模型计算得隧洞轮廓上的半孔数与观察值吻合较好。研究成果可为类似硬质岩隧洞爆破开挖中轮廓成型效果优化提供技术与方法借鉴。

唐钢2号高炉风温提升研究

对唐钢2号高炉进行热风炉制约条件的束缚及高炉操作制度的持续优化,并进行理论系统分析,采取调整烧炉参数、严格执行标准化操作等一系列提高风温的措施,使唐钢2号高炉风温水平得到显著提高,降低了生产成本。

Air-blast anti-fouling cleaning for aquatic optical sensors

In order to solve the problem of fouling of submerged optical instruments,an air-blast cleaning mechanism was integrated into an optical sensor used for measuring suspended sediment concentration(SSC)in natural waters.Laboratory experiments in a manually created fouling environment were conducted to observe the fouling process on sensor cases made of different materials,and to verify the effectiveness of air-blast cleaning in reducing fouling.Results indicated that sensors with an aluminum case experienced more serious bio-fouling than that with polyethylene case,and the air-blast cleaning mechanism was capable of reducing fouling effect on sensor signals.So the submerged optical instruments should avoid using metal materials.The duration and frequency of air-blast cleaning can be determined and adjusted depending on actual field conditions.

高炉重矿渣水泥稳定基层混合料性能研究

利用包钢高炉重矿渣碎石粗集料和石灰岩细集料,设计制备了C-C-2级配水泥稳定基层混合料,进行了其强度及抗冻性能研究。结果表明,水泥(PO32.5)剂量为3%时,C-C-2重矿渣水泥稳定混合料的7 d无侧限抗压强度可以达到5.0 MPa以上。随着水泥剂量的增加,混合料的7 d无侧限抗压强度增大。水泥剂量为4%时,C-C-2重矿渣水泥稳定混合料的最大干密度最大,同时,对于提高重矿渣水泥稳定混合料的180 d抗压强度和抗冻性能效果显著。

喷嘴数量对顶燃式热风炉性能影响的数值模拟

燃烧器是热风炉的核心部件,而喷嘴的结构是决定其性能的关键因素之一。本文基于2 350 m~3高炉配置的顶燃式热风炉,构建一个融合湍流、燃烧和传热的热风炉三维数学模型,采用数值模拟方法研究喷嘴数量对热风炉性能的影响。研究结果表明,当燃烧器配置15个喷嘴时,可以有效提高热风炉燃烧和送风性能。相比于18个喷嘴的配置,采用15个喷嘴的热风炉蓄热量提高了35.76%,送风初始温度提高50.8 K,有效送风时间延长265 s。

热风炉空燃比并行协作粒子群滑模控制策略

针对热风炉燃烧控制存在的纯滞后、大惯性和强干扰等问题,提出了一种基于并行协作骨干粒子群(Parallel Cooperative Bare-Bones Particle Swarm Optimization,PCBBPSO)优化全局滑模控制(Global Sliding Mode Control,GSMC)的热风炉空燃比控制策略;为改善热风炉空燃比控制系统动态特性,引入全局滑模策略,对燃烧系统进行优化控制,以提高系统稳定性,同时,基于热风炉燃烧系统存在的强干扰特性,利用并行协作骨干粒子群对干扰补偿进行调节以减小其对系统的影响,并求取最优控制率;仿真结果表明:与普通粒子群优化全局滑模和普通粒子群优化PID相比,该控制方法达到稳定用时分别减少了26.4 s和9.3 s,能够保持没有超调量,拥有良好稳定的跟踪和抗干扰效果;将该控制策略应用于某钢铁有限公司2200 m 3高炉配套热风炉,工程数据表明:在该空燃比策略的控制下,热风炉空燃比上下波动幅度仅为8.20%,拥有波动小、稳定性好和抗干扰性强等特点,动态响应较好,能够满足热风炉工程实际应用的需要。

两座210m高烟囱定向爆破拆除空中对碰技术研究

位于镇江市谏壁发电厂内的两座高210 m的烟囱需进行拆除,受周边环境和正常运行的两台100万机组的影响,振速不能过大。经分析论证,选择两座烟囱相对定向倒塌、空中相碰的方案是影响最小的最优方案,通过选择切口位置、精确定位倒塌方向、开设定向窗、多层次全方位防护等措施,结合对碰模拟分析结果以及现场测试数据等技术手段,最终两座烟囱在空中实现对碰,且周边保护目标安全无恙,此爆破方法为国内首例,对类似工程有一定的借鉴作用。

新钢7^(#)高炉炉凉事故分析与处理

新钢7^(#)高炉在有上部结厚的情况下计划检修,休风期间炉墙西南结厚物整体坍塌,复风过程因结厚物进入炉缸破坏了热平衡,补加净焦量不够,风口自动吹开,使用质量差的烧结开机料,最终造成炉温大凉。本文通过对高炉炉凉事故起因、处理经过及恢复到正常三个阶段进行了分析,为处理高炉炉凉事故快速恢复提供了宝贵经验。

基于粒子群算法的高炉热风炉煤气消耗优化方法研究

高炉煤气管网压力与流量具有不稳定性,导致煤气存在严重放散损失。该研究基于粒子群算法进行高炉热风炉煤气消耗优化。首先,基于高炉热风炉煤气消耗量的预测结果,建立一个以煤气产消平衡和煤气放散量最小为目标的高炉热风炉煤气消耗优化模型;其次,引入粒子群算法求解模型,获得最佳优化方案。实验结果表明,经设计方法优化后的高炉热风炉煤气放散量基本为0,证实了该方法可以有效降低煤气消耗。

唐钢2#高炉提产实践

唐钢2#高炉开炉后坚持稳定边缘、发展中心的操作制度。高炉日常操作中,通过制定合理的装料制度、高风速、高动能、高富氧、强化外围原燃料管理等措施,在球团比例40%的工艺条件下,实现高效冶炼,煤比160 kg/t,高炉利用系数3.0 t/(m ^(3)·d)达到历史新高水平。

间隔装药的殉爆起爆技术在露天矿山爆破中的应用

为了降低西沟露天石料厂的采石爆破成本,提高经济效益;应用空气袋间隔装药装置技术进行了150 mm炮孔和100 mm炮孔的爆破实验对比,同时进行了露天炮孔孔内反向和正向起爆殉爆试验对比。结果表明:采用炮孔中部空气袋间隔装置的露天矿台阶爆破,电子雷管起爆一端装药之后再利用其爆轰波殉爆起爆另一端装药,孔径大的炮孔比孔径小的炮孔殉爆起爆的爆破效果好;采用殉爆起爆技术后,做到了节能减排和提效;反向起爆爆破法与正向起爆爆破法相比,爆破效果更好。

压缩空气储能人工硐室储气库爆破开挖技术探讨

为支撑世界首例300 MW级压缩空气储能人工硐室储气库工程的安全建设,满足储气库围岩的损伤控制要求,对人工硐室储气库爆破施工中的掏槽孔区域位置、最大一段装药量和爆破临空面布置等参数设计展开分析,获得人工硐室储气库先导洞掏槽孔区域位置的基本布置方法,阐明多段位爆破装药量设计和延时设计的平衡原则,提出“一变二、二转四;二四同进、直至洞底”爆破开挖思路。通过联合应用上述3种方法,发现爆破开挖后硐壁围岩新产生的裂缝较少,表明爆破应力得到较好控制。

孔底间隔装药孔壁冲击压力特性

在良好破碎效果的前提下,通过降低孔底冲击波峰值压力来减小上向扇形深孔孔底以上岩体振动,是降低振动保护上部建筑的有效措施。为确定合理的孔底空气柱长度,采用理论研究和现场爆破试验相结合的方法,研究了孔底空气不耦合装药时空气柱长度对孔壁冲击压力的影响规律,得到了炮孔底部空气间隔不耦合装药条件下轴向不耦合因数和孔壁冲击压力曲线;基于岩石动态抗压强度,确定了适用于软、中、硬岩石的合理底部轴向空气间隔长度范围。为检验结论的合理性,进行现场验证试验并分析了爆破后采场顶板成型和爆堆块度的状况,结果表明:空气间隔层使冲击压力作用时间显著增加,而冲击压力峰值有明显减小;当不耦合因数为1.5即空气柱长度为200 mm时,孔底峰值压力衰减了73.4%,当不耦合因数为4即空气柱长度为1200 mm时,孔底峰值压力衰减了96.7%;当空气间隔层大于60 cm时,炮孔底部出现压力较低的区域。合理的底部空气间隔长度,不仅能保证良好的爆破块度,也能减小孔底峰值压力、降低爆破振动,保护采场顶板和其他保护对象。