SCR反应器结构有限元分析及其改进措施

利用Ansys软件,按照实际工程的结构形式和尺寸建立SCR反应器的三维有限元模型,在考虑自重、烟气压力及风载等荷载的组合工况下,计算反应器各个构件的内力和整体变形,参考分析设计标准,校核数值模拟结果,为反应器结构的可靠性和优化措施提供了依据。     

加氢反应器支撑圈算法分析

对加氢反应器催化剂支撑圈的几种常规计算方法进行分析,通过有限元方法进行验证,结果表明采用第二种计算方法得到的应力值与采用有限元分析方法的应力值最为接近。     

大型精制反应器的有限元分析

使用ANSYS有限元分析软件建立了大型精制反应器的三维有限元模型,在考虑包括地震等各种载荷的基础上,对它在不同载荷工况下的应力强度进行了计算,并依据JB4732《钢制压力容器-分析设计标准》进行了应力评定。结果表明该精制反应器各部分满足强度条件。     

UOP脱氢反应器人孔开孔补强计算

为了满足UOP脱氢反应器的设计要求,需要在脱氢反应器的锥壳上进行人孔开孔,针对锥壳上人孔开孔的补强计算已超出了规范推荐的校核方法。为此,本文采用有限单元法建立UOP脱氢反应器锥壳人孔开孔补强计算模型,开展锥壳、接管以及锥壳和接管相贯区的有限元分析,提取一次局部薄膜应力、三项主应力之和以及一次加二次应力,并开展强度校核,结果表明:笔者设计的UOP脱氢反应器锥壳人孔开孔强度满足要求,相应的脱氢反应器人孔开孔补强计算方法可为相关科技人员参考。     

加氢反应器简体热应力有限元分析

通过有限元软件ANSYS,分别计算了加氢反应器筒体在启动和稳态操作情况下的温度及热应力分布.结果表明,加氢反应器堆焊层与基层的交接区产生热应力集中,同时温度的快速上升对筒体热应力也有一定的影响.     

有限元方法求解化学气相淀积反应器模型(Ⅰ)——冷壁反应器模型及有限元解

建立了冷壁化学气相淀积反应器的数学模型,用Galerkin有限元方法对模型予以求解.计算中考虑了温度对物性参数的影响及自然对流因素,计算值和实验结果基本上一致.     

超高压反应器自增强处理的理论与模拟研究

超高压反应器长期在高温、高压的严酷条件下服役,受到压力波动、腐蚀因素的影响,一旦发生泄漏、爆炸事故,将造成严重的人员伤亡和重大的财产损失。本文通过理论计算与有限元模拟分析,针对某石化厂的现役超高压聚乙烯管式反应器,研究其自增强处理前、后,工况条件下反应器沿壁厚方向当量应力的变化规律,并利用安全系数,量化评估自增强处理对反应器安全性的影响。     

刮壁搅拌桨的最优设计

运用罚函数Ｇａｌｅｒｋｉｎ加权余量有限元数值算法模拟了Ｖｏｔａｔｏｒ、Ｃ＆Ｒ反应器和刮壁槽式釜中轴截面的流速和剪切分布。计算结果表明，Ｖｏｔａｔｏｒ，Ｃ＆Ｒ反应器中流动和剪切分布较刮壁槽式釜更有利于流体的混合和壁面的传热。对Ｃ＆Ｒ反应器，采用无间隙刮板，其传热和混合性能优于有间隙刮板。建议刮壁搅拌反应器的设计采用类似Ｖｏｔａｔｏｒ和Ｃ＆Ｒ反应器的环隙结构和无间隙的刮板形式。     

有限元方法求解化学气相淀积反应器模型(Ⅰ)——冷壁反应器模型及有限元解

建立了冷壁化学气相淀积反应器的数学模型,用Galerkin有限元方法对模型予以求解.计算中考虑了温度对物性参数的影响及自然对流因素,计算值和实验结果基本上一致.     

加氢反应器油气出口与卸料口的安全性能分析与评定

加氢反应器是石油炼制过程中的重要及危险的设备,加氢反应器的油气出口与卸料口接管方式一般是嵌入式的结构。基于有限元分析对加氢精致反应器R101的油气出口与卸料口部分进行应力分析,找出其相对最危险的部位,在其部位取应力评定处理线运用相关压力容器的理论对其检验结果进行计算,从而分析计算。     

火电厂选择性催化还原脱硝技术的可行性研究

选择性催化还原（SCR）技术是目前研究较多的治理氮氧化物的方法。本文综述了选择性催化还原法降低氮氧化物排放的机理,介绍了SCR技术反应器的设计,催化剂的使用情况和研究现状,同时展望了这一技术领域的重点研究方向。     

选择性催化还原蜂窝状催化剂内流动特性的多尺度模拟

为提高选择性催化还原(SCR)脱硝反应器内催化剂的脱硝效率和使用寿命,从细观和宏观两个角度对SCR脱硝反应器的流动特性多尺度数值进行研究。在细观层面研究了不同高度的催化剂层产生的阻力随进口速度的变化,并计算得到阻力关系式。宏观层面,基于阻力关系式,计算出催化剂宏观结构数值模拟所需的粘性阻力系数和惯性阻力系数,对反应器内的流动特性进行数值模拟,并将其结果与实验数据对比,最大误差为8.6%。将关系式应用于具有不同结构(蜂窝状和斜板状)催化剂的脱硝反应器中,计算结果与文献值趋势基本一致,最大误差为12.9%。     

The Operating Performance of Stirred Column Reactor

A theoretical analysis of the effects of flow and mixing on the operating features of astirred column reactor(SCR)with multistage mixers and cooling partition plates was conducted.Amethod for calculating the concentration reduction for a second order chemical reaction in a SCRwas proposed.The reactants concerned were pre-mixed before feeding into the SCR.The SCR wascomposed of a number of stages with interstage backmixing.Experimental investigation with variousreaction media were carried out in order to study the effect of mixing on the operational performanceof the SCR.The experimental data were compared with the theoretical results.     

Study of SCR cold-start by energy method

The cold-start of a prototype diesel engine exhaust aftertreatment system was analyzed using a simplified energy balance to study the impact of system design changes on the performance of the selective catalytic NOx reduction reactor. The simplified energy balance method is shown to be a viable tool for system-level analysis of the aftertreatment performance. The results indicate that without an external energy supply the best way to shorten the selective catalytic reduction (SCR) reactor light-off time is to reduce the system thermal inertia by including a metallic diesel oxidation catalyst (DOC) and moving the SCR reactor upstream. Such optimization of the aftertreatment architecture is found to significantly reduce SCR light-off time for the configurations examined. Electrical heating applied to the SCR and DOC reactors can also reduce the light-off time. The system architecture optimization, however, is subject to vehicle under-hood packaging restrictions. To meet more stringent emission standards in the future, a combination of architecture optimization and electrical heating will be required.     

某燃煤电厂300MW机组SCR烟气脱硝装置结构优化

SCR烟气脱硝装置中烟气流场的分布及还原剂（NH3）与NOx的混合效果对脱硝效果起着重要作用,因此,采用数值模拟技术对于初步设计的SCR烟气脱硝装置进行结构优化是目前国内外SCR烟气脱硝装置设计必不可少的一部分。本研究采用Fluent软件对某燃煤电厂300MW机组SCR烟气脱硝装置内的烟气流动、第一层催化剂入口NH3与NOx的混合和系统压降等方面进行模拟,结果表明：BMCR工况下,结构优化后的SCR烟气脱硝装置AIG上（下）游、第一层催化剂入口和装置出口截面烟气流速相对标准偏差不超过15%;第一层催化剂入口截面NH3/NOx摩尔比相对标准偏差不超过10%;第一层催化剂入口截面烟气进入最大偏差角度处于±10°范围之间;系统压降低于800Pa。合理的设计导流板能够起到抑制弯管以及变截面所引起的流场分离现象、消除大旋流的产生使烟气更加流畅地进入催化剂等作用。     

栅格型导流板对SCR反应器内流场影响特性分析

基于某水泥厂环保改造项目,对SCR反应器进行设计改造,应用计算流体力学软件对SCR反应器内流场进行数值模拟研究,前期获取大量实际运行数据,通过算法验证,本文使用的模拟方法具有可靠性,与实际较为吻合。随后,在比较分析不加装导流板反应器和原反应器（内置扇形导流板及多孔整流层）内流场的基础上,进一步研究了倒V型导流板+栅格整流层和栅格型导流板对SCR反应器内流场特性的影响,结果表明：栅格型导流板能有效改善流场均匀性,并且使得进入催化剂层的烟气速度偏差大大降低。     

The process design and simulation for the methanol production on the FPSO (floating production,storage and off-loading) system

A process for methanol production from 100 MM scfd of stranded gas and CO₂ is proposed and simulated using a commercial process simulator, PRO/II v.9.1, for a FPSO (floating production, storage, off-loading) system. The process consists of Steam-CO₂ Reforming (SCR), methanol synthesis, a Reverse Water-Gas Shift (RWGS) reaction and ancillaries with recycle streams to SCR and RWGS. All reactors were simulated using the Gibbs reactor model. Also, the Plug Flow Reactor (PFR) model with reaction rate equations was used for the methanol reactor and the result was compared to the Gibbs reactor model. To maximize the use of the carbon source in stranded gas and CO₂ while avoiding an undesirable increase in process size, the optimum recycle ratios were calculated with a satisfying constraint, a steam-to-carbon ratio ≥ 1 in the SCR. In the proposed Methanol-FPSO process the RWGS reactor can maximize CO₂ utilization and case studies were performed to analyze the influence of RWGS.     

Impact of Biodiesel-Based Na on the Selective Catalytic Reduction of NOx by NH3 Over Cu–Zeolite Catalysts

A single-cylinder diesel engine was used to investigate the impact of Na on Cu–zeolite SCR catalysts using 20 % bio- and petrol-diesel fuel blend (B20) with elevated levels of Na. The Na exposure was performed on light-duty (DOC–SCR–DPF) and heavy-duty (DOC–DPF–SCR) configurations of the diesel emissions control devices. The accelerated Na aging is achieved by exposing the system to elevated levels of Na that represent full useful life exposure (700,000 km) and periodically increasing the exhaust temperature to replicate DPF regeneration. After aging, the NO_x performance and relevant chemistry of the SCR catalysts were evaluated in a bench flow reactor. The SCR in the DOC–SCR–DPF configuration was found to be severely affected by Na contamination, especially when NO was the only NO_x species in the simulated exhaust gases. In the DOC–DPF–SCR configuration, no impact is observed in the SCR NO_x reduction activity. Electron microprobe analysis (EPMA) reveals that Na contamination on the SCR samples in the DOC–SCR–DPF configuration is present throughout the length of the catalysts.     

水泥窑尾系统烟气SCR脱硝工艺优化方法

为了提高SCR脱硝效率,以水泥窑尾系统为研究对象,提出烟气SCR脱硝工艺优化方法。依据SCR脱硝工艺脱硝方式,选择的V2O5-TiO2成分催化剂,从脱硝控制、反应机理、反应物扩散三个方面,确定水泥窑尾系统烟气SCR脱硝工艺脱硝的反应原理;计算SCR脱硝工艺脱硝的效率,结合SCR脱硝工艺反应原理,提取SCR脱硝工艺中影响SCR脱硝工艺脱硝效率的烟气温度和流速、氨氮供应量、催化剂性能等因素;采用最小二乘支持向量机,设定优化函数,优化SCR脱硝工艺的烟气温度和流速、氨氮供应量、催化剂性能。设定SCR脱硝工艺试验参数值,应用试验结果：平均供氨流量在设定值范围±0.3 m3/h上下波动,SCR反应器入口NOx浓度,在设定值的上0.4 mg/m3、下0.3 mg/m3范围内波动,SCR出口NOx浓度在设定值上下R0.5 mg/m3波动,对于脱硝过程控制能力高,经脱硝效率计算公式计算,优化后的SCR脱硝工艺脱硝效率提高了3.75%。