对废热锅炉的使用以及排废气烟道、风机布置的看法

彰武玻璃厂自投产安装的两台废热锅炉的排烟管道,开始布置如图1所示。实践中,发现在两台废热锅的排烟管道中,气体走一条管道互相干扰,又因废气进烟囱的入口处时与经烟道直接排入烟囱的废气相互顶撞,大大降低了抽力,当时锅炉前的烟箱温度为300℃左右,蒸气压力最大为2.5公斤/厘米~2,蒸发量最大为1.8吨/时·台,如附图2所示。一九七五年我们对两台废热锅炉的排烟管道进行改造,每台废热锅炉采用单独排烟管道和风机,并另立一个内径为920毫米,高20米的烟囱来排除经过废热锅炉的废气。由于排风机抽力增大、锅炉烟箱温度提高到380℃,比改造前提高80℃。由于温度增高,蒸     

稀硝酸生产装置中卧式火管废热锅炉的水侧腐蚀问题

概况南京化学工业公司氮肥厂硝酸车间二硝工段系采用全低压法稀硝生产流程。产量约为10万吨/年。工段内共有直径为2000毫米的氧化炉6台,其后配有废热锅炉3台。每2台氧化炉合用1台废热锅炉。废热锅炉为卧式火管锅炉。锅炉蒸发量5吨/小时,生产饱和蒸汽,蒸汽压力为13表压,温度为194℃。进入废热锅炉的NO_2气体压力为0.9表压,温度为820℃;从废热锅炉排出的NO_x 气体温度为250℃。废热锅炉的总布置图如图1。从氧化炉来的高温NO_x 气体从二侧进入废热锅炉高温端的气室。然后进入火管。废热锅炉筒     

广氮油气化盘管式废热锅炉改造

广州氮肥厂重油加压气化装置是采用盘管式废热锅炉流程,两台气化炉,两台废热锅炉。投产后废热锅炉经常损坏,使装置运转率只有53%。为此,化工部要求广东省石油化工局组成以化工部上海化工研究院、化工部化工机械研究院、广东省石油化工设计院、广州氮肥厂参加的废热锅炉攻关组,对废热锅炉进行     

锅炉汽包热应力的产生及控制研究

就锅炉汽包壁温度变化引起的热应力进行讨论,详细分析了汽包上下壁、内外壁温差的产生原因、温差引起的热应力的产生过程和热应力对汽包寿命的各种影响因素,提出了控制汽包壁温差的措施,以保证汽包安全运行。     

造气废热锅炉改造小结

以造气火管式废热锅炉的改造为主线,对火管式废热锅炉存在的火管变形扭曲、热应力无法消除、露点腐蚀、焊接工艺、水侧的氧腐蚀和垢下腐蚀问题进行了剖析。提出了改进意见,即热水加热器管间距由32mm扩至50mm、软水加热器及套管式过热器最上端增加防腐护瓦、设计1台专用制贫气锅炉、改进材质等,并对改造后的套管式锅炉结构特点及其使用效果进行了介绍。     

加热炉的废热回收

日本出光兴产公司爱知炼油厂的原油处理能力13000桶/日,该厂以加热炉的废热回收为中心,实施了一系列节能改造措施,取得了显著效果。1.回收废热,降低排气温度:采取空气预热器和废热锅炉相结合进行热回收的方法,在常压蒸馏装置,石脑油脱硫装置,石脑油重整装置,煤柴油脱硫装置上各设置一台空气预热器,又在重油脱硫装置和制氢装置共用的烟道上设置一台废热锅炉。     

废热锅炉管程出口局部结构有限元分析及其优化

利用ANSYS有限元分析软件对废热锅炉管程出口Q345R作为过渡段(连接废热锅炉管板和S30408管程出口)的结构进行分析计算,得到热应力和结构应力的数值与位置,并对应力进行了分析评定。依据分析结果,论证了设置Q345R过渡段的合理性和热应力分析计算的必要性。     

内装式废热锅炉的运行

沸腾炉的废热利用,南化公司氮肥厂自1970年采用内装式中压废热炉以来已运行八年。早期,锅炉虽曾遇到过一些问题,但从1973年初,我们对内装锅炉结构改进后,到现在已经连续安全运行了五年,取得了一定成效。通过两台锅炉的生产实践,使我们对内装式中压废热锅炉的性能和特点有所了解,这里将近年来的运行情况和我们的认识作一扼要介绍。     

水煤气工序提高蒸汽自给率的措施

我厂水煤气工序有8台φm固定层发生炉。除5~#、6~#炉各设置一台废热锅炉外,其余6台炉每两台配置一台废热锅炉(φ2262×2464,传热面积487m~2)。锅炉给水未经预热直接送入废热锅炉中,影响了产气量。另外,上吹煤气的热量未回收利用,造成热量损失,副产蒸汽少且消耗高。     

乙烯装置废热锅炉焦炭燃烧过程的研究

采用国内某乙烯厂废热锅炉生成的焦炭为试验原料 ,研究了乙烯装置废热锅炉焦炭的微观结构。在自行设计的废热锅炉焦炭燃烧试验装置中 ,考察了烧焦温度、氧气流量两主要因素对乙烯装置废热锅炉烧焦过程的影响。试验结果表明 :乙烯装置废热锅炉焦炭富碳而缺氢 ,其晶体结构与 2H -石墨相接近 ;在乙烯装置烧焦过程中 ,温度对烧焦过程影响显著 ,氧气流量对烧焦过程影响不大 ,并由此提供了加快乙烯装置废热锅炉烧焦速度的依据     

水冷壁气化炉紧急停车渣层热应力分析

基于实验室小型水冷壁气流床气化炉,研究了两种油渣浆气化后在炉内壁形成渣层的内部结构及组成。建立了气化炉水冷壁的三维传热和应力模型,对气化炉紧急停车时炉壁的热应力变化及其分布进行了模拟计算。计算结果表明：渣层中越靠近渣层表面,热应力的变化越大;靠近水冷管和渣钉处的渣层热应力变化相对较小;渣层表面温度变化相同时,孔隙率大的渣层产生的形变较大。     

急冷锅炉EH-112A应力分析与强度评价

针对急冷锅炉EH-112A的国产化问题,应用ANSYS软件分别建立了分析温度场和结构应力场的三维有限元模型,分析和计算了不同工况下的温度场和应力场,并依据应力分类法进行了强度评价。     

Alumina/NiCu Laminate under Thermal Shock up to 1000°C: II, Prediction of the Laminate Behavior

In this investigation, a multilayered, multimaterial system with strong interface subjected to thermal shock loading was analyzed. The analysis was based on a one-dimensional spatio-temporal finite difference scheme of the temperature field, and the thermal residual stresses and zero misfit stress temperature were considered. Using a failure criterion based on crack initiation, the number of broken layers due to thermal shock and residual mechanical strength at room temperature could be predicted. Furthermore, the room temperature residual strength of the laminate as a function of thermal shock temperature was constructed, demonstrating steplike behavior. Using this model, the mechanical behavior of the alumina/NiCu laminate system subjected to thermal shock loading of up to 1000°C was predicted. The model revealed the superiority of this material system over monolithic ceramics under thermal shock conditions.     

抛煤机锅炉炉内增拱对炉膛出口烟温的影响

分析了抛煤机锅炉炉内增拱后的炉内燃烧性能。具体考察了炉内辐射层有效厚度、炉内平均有效系数、炉膛黑度等参数的变化对炉膛出口烟温的影响。证实了炉内增拱可较大的提高炉内燃烧强度，提高抛煤机锅炉的热效率和炉膛出口烟温。     

Comparison of stress evolution under TGO growth simulated by two different methods in thermal barrier coatings

The growth of thermally grown oxide (TGO) is a significant factor affecting the failure mechanism of thermal barrier coatings (TBCs) during cyclic high temperature service. In this work, a complicated finite element model with two semicircles reflecting the undulation of TGO interfaces was proposed, and four representative shapes of TGO interfaces were selected. There are mainly two methods to simulate TGO growth under high temperature, and each method was achieved by implementation of user subroutines in finite element method. A total of 100 thermal cycle loads were applied to the TBCs continuously. The stress evolution in the layers of Top Ceramic Coating (TC) and Bond Coating (BC) at the end of each thermal cycle load was obtained, the influence of TGO growth on stress evolution was analyzed, the differences between two methods of TGO growth were discussed. The results show that under TGO growth simulated by the first method, the stress distribution in the y direction does not change in both TC and BC layer, and the maximum stress decreases a lot in TC layer but nearly remains the same in BC. When the growth of TGO was simulated by the second method, stress evolution is complex and undergoes up to five stages with a small undulation or convex of TGO interfaces. Stress evolution in BC layer remains as the same as in the first method. Moreover, the maximum stress increases continually in BC layer. The comparison of these two simulation method would help to study the failure of TBCs caused by TGO growth.     

Discrete element modeling of the transient heat transfer and toner fusing process in the Xerographic printing of coated papers

In this study, a computer model based on discrete element method is employed to simulate the unsteady state heat transfer from the fuser roll to the toner and coating layer during the Xerography printing of coated papers. The model coating layers consisted of randomly arranged spherical pigment and latex particles with commercially relevant size distributions. Effects of coating characteristics, toner size, multiple toner layers, toner melting energy, toner thermal conductivity, coating layer thermal conductivity, and fuser roll temperature and pressure were investigated. Iso-thermal contours of fusing time were generated to demonstrate the relative importance of different fusing conditions and toner properties. Simulation results showed that temperature variation highly depended on the toner size, toner melting energy and the fuser roll temperature. Moreover, simultaneous coupling of the compressive stress and heat transfer indicated that the pressure exerted by the fuser roll did not significantly affect the rate of heat transfer.     

基于ANSYS软件的热油管路保温的数值模拟

应用ANSYS软件对埋地热油管道沿径向温度进行了数值模拟,得到了不同保温层厚度时管道径向温度及热流量的变化。分析了含蜡层的径向温度变化,随着保温层厚度的增加,保温层内部温降变化减小,管道向外传递的热流密度逐渐减小,保温效果更好。热流量减小的速度随着保温层厚度的增加变得缓慢,模拟结果与编制计算机程序计算结果相吻合。     

Strengthening the ZrC-SiC ceramic and TC4 alloy brazed joint using laser additive manufactured functionally graded material layers

In order to improve the ZrC-SiC and TC4 brazed joint property, functionally graded material (FGM) layers (two SiC particles reinforced TC4-based composite layers) were designed to relieve the residual stress in the ZrC-SiC and TC4 brazed joint. The FGM layers were fabricated on the TC4 surface using laser additive manufacturing technology before the brazing. Then the TC4 coated with the FGM layers and ZrC-SiC ceramic were brazed using Ti-15Cu-15Ni (wt%) filler. According to the SEM and TEM results, the volume fractions of SiC particles in the FGM layers could reach 20% and 39% respectively. Ti from the braze filler and TC4 reacted with the ZrC-SiC ceramic to form TiC and Ti₅Si₃ adjacent to the ZrC-SiC ceramic. The shear test results indicate that the adoption of the FGM layers and the brazing temperature both affected the joint property significantly. The FGM layers could benefit the mitigation of coefficient of thermal expansion (CTE) mismatch between the ZrC-SiC and TC4, so that the residual stress caused by the CTE mismatch in the joint was relieved and the joint strength increased. The brazing temperature would affect the microstructure of the brazing seam and then control the joint strength. When the ZrC-SiC ceramic and TC4 coated with the FGM layers were brazed at 970?°C for 10?min, the maximum shear strength could reach 91?MPa, and cracks propagated in the ZrC-SiC ceramic substrate during the shear test.     

高温高压锅炉在干熄焦工程中的应用

结合以往对各种干熄焦锅炉的标定数据以及在干熄焦锅炉选择过程中存在的制约因素,对干熄焦装置的生产能力、工程投资及企业现状等因素进行对比分析,为干熄焦锅炉炉型的选择提供了建议。同时针对高温高压自然循环干熄焦热力系统和中温中压联合循环干熄焦热力系统,在节能方面、锅炉效率、钢材消耗、系统电力消耗、发电量的差异以及锅炉的开工与运行方面的差异进行了对比分析,进而了解两种参数的热力系统在各方面的优缺点。     

固体火箭发动机的热安全性研究

采用带源项的热传导方程,对固体火箭发动机在外界热源作用下的加热过程进行了数值模拟,分析了固体发动机内推进剂在外界热源作用下的燃烧特点,并确定了发动机产生热危险性的临界温度和起始燃烧时间。研究结果表明,在热传导方程中加入化学反应源项,可以有效地模拟发动机在外界热源作用下的加热过程;推进剂产生热危险性的临界温度为520～525K;在外界火焰作用下,发动机内的推进剂将点火燃烧,随着外界火焰温度的上升,推进剂起始燃烧的延迟时间减少。