共查询到18条相似文献，搜索用时 609 毫秒
1.
针对现场固定空燃比燃烧导致无法根据波动燃气热值匹配最佳助燃空气,使热风炉热损失增加;残氧检测仪直接检测热风炉烟道残氧量,将导致氧化锆损耗快、高炉煤气费用计量单一等问题。针对以上问题设计一种残氧燃气分析系统,该系统并行于热风炉控制系统的前馈控制,将少量高炉煤气、空气先通入该系统进行燃烧并调整自身空燃比,得到最佳空燃比作用于热风炉控制系统并对并行系统残氧含量、高炉煤气热值进行数值模拟和相关性分析。通过改进PSO算法优化RBF神经网络预测方法对稳定运行系统建立模型,预测煤气热值作为优化热风炉空燃比,评价煤气质量、费用计量的有效参考条件。经实验仿真测试,该系统可有效提高空燃比修正精度,延长氧化锆使用寿命,减少热风炉热损失。 相似文献
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苏凌均 《辽宁科技学院学报》2005,7(2):19-20
旋流顶燃式热风炉与内燃式热风炉相比在风温水平上,提高了一个档次,在整体结构上旋流顶燃式热风炉的蓄热面积更大,燃烧更充分,更均匀.在热风炉的日常维护和检修上,旋流顶燃式热风炉避免了燃烧室内部掉砖阻碍煤气畅通以及煤气泄漏等现象,减少了检修量,有利于安全生产. 相似文献
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基于设计的试验方案,对常见的生活垃圾如木筷、垃圾袋、棉布及其混合组分进行燃烧试验研究,得出了各组分燃烧特性曲线以及各组分的平均活化能;在此基础上根据各组分燃烧时的平均活化能建立了用于计算各种不同配比混合垃圾活化能的经验公式;通过生活垃圾活化能的试验进行验证,该计算公式简便实用,可运用公式计算混合生活垃圾的活化能。 相似文献
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发生炉生产煤气过程中,炉内煤气经开启的加煤阀向上泄露至缓冲煤仓和储煤仓,容易引起爆炸、人员中毒等事故,造成能源浪费和环境污染。为了降低缓冲煤仓煤气含量,并有效地封堵煤气进入储煤仓,提高置换效率及能源利用率,降低闪爆事故发生率,针对某煤气发生炉建立缓冲煤仓三维模型。采用FLUENT对缓冲煤仓吹扫N2置换煤气的过程进行模拟,探究一级进气管长和二级进气角度对缓冲煤仓内煤气置换时间的影响规律。试验结果表明,缓冲煤仓内N2浓度由初始60%急剧增加,8s后达到99%,之后N2浓度增长缓慢。CO浓度由初始30%逐渐降低,8s后接近于0,完成置换。0°进气孔优于90°进气孔进气管长占缓冲煤仓总高度的比例约为1/3时为最优,置换时间更短。该结构通过两级协同吹扫,有效解决加煤时缓冲煤仓的煤气外泄问题和储煤仓闪爆问题。 相似文献
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通过热轧加热炉烧嘴热态试验,分析了天然气掺烧条件下烧嘴流量特性的变化规律,结果表明:等热值条件下,随着天然气掺烧比例的增大,混合煤气密度增加,调焰烧嘴稳定燃烧时煤气压力提高;在天然气比例为22%时,煤气压力提高约20%。 相似文献
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采用正交实验法分析出绿色木霉 3.3711纤素酶系各组分最适酶解条件组合分别为(pH5 .0、4 5℃ ) (C1酶 ) ,(pH3.5、5 5℃ ) (Cx 酶 )和 (pH4 .5、6 5℃ ) (βG酶 )。分析比较了分别使用纤维素粉和麦麸为单一或混合碳源时在产酶过程中各组分酶的最高酶活 ,比酶活及其形成时间和分泌特性。结果表明 ,同种碳源不同浓度所产酶系中C1比酶活相对稳定 ,C1和Cx 酶活分别形成一个和两个高峰 ,βG酶均为一个高峰。混合碳源使各组分酶活高峰期相对一致 ,高峰期稳定时间延长和酶量增加。 相似文献
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任瑞忠 《辽宁科技学院学报》2014,(3):6-7
北营新1号高炉通过优化高炉煤气处理流程,配置旋切顶燃式热风炉,采用前置预热炉、热管换热器分别预热助燃空气和煤气,使用带横梁的炉箅子技术、管道保温技术以及优化烧炉技术等,为送风温度达到1250℃创造了条件。高炉在精料基础上,通过控制合理炉腹煤气量指数和理论燃烧温度,优化煤气流分布,规范高炉操作等措施,2013年全年平均风温1248℃,达到国内同型高炉领先水平。 相似文献
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《浙江大学学报(A卷英文版)》2020,(3)
目的:前后墙对冲燃烧锅炉在实际运行中普遍存在沿炉膛宽度CO体积分数呈中间低、两边高的分布特点。该分布特点往往伴随着锅炉效率降低、炉膛出口NOx排放偏高、侧墙结渣和高温腐蚀严重等一系列问题。本文旨在分析前后墙对冲燃烧锅炉内CO分布规律的形成原因,为机组运行调整与燃烧系统改造等工程实践提供理论依据。创新点:1.针对煤粉炉燃烧过程中存在剧烈气固反应流的特点,定义了与气、固相质量变化无关的风、煤分布系数ηa和ηp,进而得到了风/煤混合系数η。2.对比炉膛不同区域内的CO分布与风/煤混合系数分布,结合炉膛的空气动力学特性,解释了前后墙对冲燃烧锅炉内CO分布特征的形成过程。方法:1.建立一台660 MWe前后墙对冲燃烧锅炉的数值模型,并通过现场测量数据与模拟数据的比较,验证模型的有效性(表5和图3)。2.定义炉内风、煤分布系数与风/煤混合系数(公式(1)～(3))。3.对比不同特征截面上CO分布特性与风/煤混合特性,探讨二者之间的关联性(图4和5)。3.分析风的分布和煤的分布分别对风/煤混合特性的影响(图6和7)。4.综合考虑炉内气流结构、风和煤的分布及其混合特性,揭示炉内CO分布规律的形成原因(图4～9)。结论:1.对前后墙对冲燃烧锅炉而言,燃烧器区域出口的CO大量聚集在炉膛中间至侧墙区域,燃尽风区域出口的CO则主要集中于侧墙附近。2.CO分布与风/煤混合系数分布基本一致。3.在整个炉膛空间内,风和煤粉皆有向侧墙流动的趋势,但煤粉更加聚集在侧墙周围。4.在燃烧器区域,对冲气流使得风与煤粉向侧墙流动,然后在炉膛四角形成涡流;四角涡流导致烟气在沿侧墙上升的过程中发生明显的气固分离,使煤粉被甩至侧墙附近并在那里燃烧,形成高浓度CO;5.在燃尽风区域,燃尽风与侧墙附近烟气的混合并不理想,因此侧墙附近的高浓度CO难以消除,最终导致沿炉膛宽度的CO体积分数呈中间低、两边高的分布特点。6.基于上述结果,本文分析了当前应用中存在的问题,并提出了改进建议。 相似文献
9.
乙酸与环己酮-环己烷二元混合液体系的热力学性质 总被引：1，自引：1，他引：0
常压下测定了乙酸-环己酮和乙酸-环己烷2个二元混合体系纯组分及混合液在303.15-333．15K温度内全浓度范围的密度,计算了2个混合体系的超额摩尔体积Vm^E,乙酸-环己酮混合液的Vm^E呈负偏差,而乙酸-环己烷体系《为正值。用Redlich-Kister方程关联不同温度下研究体系的Vm^E与组分摩尔分数的关系,这2个二元混合系最大标准偏差小于0．5％,说明两者有较好一致性。探讨了极性有机溶剂与其他有机物混合后分子间特殊相互作用。 相似文献
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Experiment and mechanism investigation on advanced reburning for NOx reduction： influence of CO and temperature 总被引：4，自引：0，他引：4
Wang ZH Zhou JH Zhang YW Lu ZM Fan JR Cen KF 《Journal of Zhejiang University. Science. B》2005,6(3):187-194
Pulverized coal reburning, ammonia injection and advanced reburning in a pilot scale drop tube furnace were investigated. Premix of petroleum gas, air and NH3 were burned in a porous gas burner to generate the needed flue gas. Four kinds of pulverized coal were fed as reburning fuel at constant rate of 1g/min. The coal reburning process parameters including 15%～25% reburn heat input, temperature range from 1100 ℃ to 1400 ℃ and also the carbon in fly ash, coal fineness, reburn zone stoichiometric ratio, etc. were investigated. On the condition of 25% reburn heat input, maximum of 47% NO reduction with Yanzhou coal was obtained by pure coal reburning. Optimal temperature for reburning is about 1300 ℃ and fuel-rich stoichiometric ratio is essential; coal fineness can slightly enhance the reburning ability. The temperature window for ammonia injection is about 700 ℃～1100 ℃. CO can improve the NH3 ability at lower temperature. During advanced reburning, 72.9% NO reduction was measured. To achieve more than 70% NO reduction, Selective Non-catalytic NOx Reduction (SNCR) should need NH3/NO stoichiometric ratio larger than 5, while advanced reburning only uses common dose of ammonia as in conventional SNCR technology. Mechanism study shows the oxidization of CO can improve the decomposition of H2O, which will rich the radical pools igniting the whole reactions at lower temperatures. 相似文献
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In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were studied. The results showed that the mixing time was shortened with the increase of fluid velocity. All the discrete numbers of the reactor were above 0.2. The serial number n was 2.5 -3.0. It was judged accordingly that the reactor fluid state was continous stirred tank reactor （CSTR） mainly. When the inspiratory capacity increased the mixing time of the reactor was shortened. Thus the air input was beneficial for the fluid mixing. During the three phases mixing process, the mixing time of the reactor could be decreased by the n increase of carrier and air loading together, but the change was not significant. The parameters affecting the reactor fluid state were fluid velocity, inspiratory capacity and carrier. KLa could be increased with the air loading increase, and at the same gas/liquid ratio when the pressure drop was high, KL~ value was increased. The amount of carrier complex influence on KLa. As the carrier loading continued to increase, its value had been dropped but the changes was not significant, and optimization condition was found at above 800 1 000 g carrier loading （pouzzolane） or 600 g PVC. Under gas/liquid ratio of 0.8% -5.2%, KLa was （0.62-1.37）×10^-2· s^-1. 相似文献
15.
RH和RH-KTB精炼过程中钢液流动和混合特性的研究 总被引：7，自引：0，他引：7
The flow and mixing characteristics of molten steel during the vacuum circulation refining,including RH(Ruhrstahl-Heraeus) and RH-KTB(Ruhrastahl-Heraeus-Kawasaki top blowing) processes,were investigated on a 1/5 linear scale water model of a 90t multifunction RH degasser,The circulation rate was directly and more accurately determined,using a new method by which the more reliable results can be obtained.The fluid flow pattern and flow field in the ladle were demonstrated,observed and analyzed.The mixing time of liquid in the ladle was measured using electrical conductivity method.The residence time distribution in the RH model was obtained by tracer response technique.The influence of the main technological and geometric factors,including the gas top blowing*(KTB) operation,was examined.The results indicated that the circulation rate of molten steel in the RH degasser can be fairly precisely calculated by the formula:Q1p=0.0333Qg^0.26Du^0.69Dd^0.80(t/min),where Qg-the lifting gas flow rate(NL/min);Du and Dd-the inner diameters of the up and down-snorkels(cm),respectively.The maximum value of circulation rate of molten steel in the case of the 30cm diameters either of the up-and down-snorkels for the RH degasser(the “Saturated” rate) is approximately 31 t/min.the corresponding gas flow rate is 900NL/min.Blowing gas into the vacuum chamber through the top lance like KTB operation does not markedly influence the circulatory flow and mixing charateristics of the RH process under the conditions of the present work.There exist a major loop and a large number of small vortices and eddies in the ladle during the RH refining process.A liquidliquid two-phase flow is formed between the descnding stream from the down-snorkel and the liquid around the stream.All of these flow situation and pattern will strongly influence and determine the mixing and mass transfer in the ladle during the refining.The correlation between the mixing time and the stirring energy density is τmε^0.50 for the RH degasser.The mixing time rapidly shortens with an increase in the lifting gas flowrate.At a same gas flow rate,the mixing times with the up-and down-snorkel diameters either of 6 and 7cm are essentially same.The 30cm diameters either of the up-and down-snorkels for the RH degasser would be reasonalble.The concentration-time curve showed that three circulation cycles are at least needed for complete mixing of the liquid steel in the RH degasser. 相似文献
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李涛涛 《河北能源职业技术学院学报》2014,14(4):70-72
九里山矿1983年投产,2009年河南工业和信息化厅组织对其瓦斯进行鉴定,属于严重煤与瓦斯突出矿井。10月27日0时36分,在该矿井16采区16031上风道掘进工作面发生煤与瓦斯突出事故,零点班刚进入该掘进工作面区域的18名矿工全部遇难。如何有效防止再次事故的发生,成为全矿井急切解决的问题。 相似文献
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150吨复吹转炉底部供气模拟研究 总被引：1，自引：0，他引：1
通过水模型实验,研究了复吹转炉底部供气流量、喷嘴数目及分布对熔池均混时间的影响.通过正交设计试验,测定了不同底气流量、喷嘴数目及不同的位置条件下的均混时间,根据水模试验优化的结果为本钢150吨复吹转炉底部供气元件的布置提供了依据. 相似文献
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A coal slurry mixing tank is a key piece of equipment in the preparation of coal slurry for direct coal liquefaction.It is a gas-liquid-solid three-phase mixing device.Based on the performance of the existing coal slurry mixing equipment,a type of test equipment for horizontal continuous coal slurry preparation was developed,but to this point has limited research results.The test equipment consists of a mixing cylinder,mixer,stirring impeller and other components.Slurry mixing experiments were undertaken using the prototype,testing the performance of the device.A mathematical model was proposed specifically for the operation of a coal slurry mixing tank that is horizontally operated with high slurry concentration and rotary flow.The flow field in the horizontal coal mixing tank was simulated with the computational fluid dynamic （CFD） method.The experimental results match well with the CFD simulation results.Results show that the test device of a coal slurry mixing tank can be used to model the mixing of pulverized coal and the solvent oil.A strong correlation was obtained. 相似文献