CTA干燥机列管腐蚀机理及原因分析

在精对苯二甲酸(PTA)生产中,氧化单元的粗对苯二甲酸(CTA)干燥机列管发生严重腐蚀,影响了装置的稳定运行,对干燥机列管腐蚀的机理及原因进行了分析,并提出延长干燥机列管使用寿命的措施。结果表明:干燥机常见的腐蚀形态是点蚀、垢下腐蚀、磨损腐蚀,腐蚀形态与CTA物料中溴离子含量、物料温度以及列管材质等有关;列管表面的点蚀和垢下腐蚀以及物料对管子的冲刷磨损是CTA干燥机列管腐蚀的主要原因;控制CTA中溴离子含量、优化工艺参数、更换高性能材质的列管,可有效缓解列管腐蚀,从而提高干燥机的运转周期和运行稳定性。     

中变煮沸器不锈钢列管腐蚀机理研究项目通过技术鉴定

由武汉化工学院和湖北省化工厂共同研制的“中变煮沸器不锈钢列管腐蚀机理研究”于1993年11月17日通过了省石化厅组织的专家技术鉴定.该课题针对合成氨脱碳系统中变煮沸器1Cr18Ni9Ti列管失效,采用动态高温模拟实验方法和高温加背压实验方法,研究论证了该列管在钾碱液中发生孔蚀破坏的主要原因;阐明了腐蚀机理并通过创新的实验设计,给予证明.湖北省化工厂2年零6个月的生产运行实践证明,腐蚀机理和防腐措施是科学合理的,为工厂创造年直接经济效益52.6万元,节约资金38万元(所节省的设备购置费、安装费、检修费及故障检修费等都尚未计     

烧碱蒸发器列管的腐蚀失效分析

通过现场调研，宏观检查，金相和扫描电镜等分析手段，对某化工厂烧碱蒸发器列管的腐蚀失效原因进行了研究。结果表明：蒸发器列管宏观上呈全面腐蚀；烧碱液的腐蚀和结晶盐颗粒的冲刷、磨蚀，是造成列管失效的主要原因。     

中变煮沸器不锈钢列管腐蚀失效分析

<正> 一、前言 近年来,我国化工行业不锈钢设备的应用日渐增多,出现的不锈钢腐蚀破坏事故也相继增加,其中危害性最大、发生频率最高的是局部腐蚀破坏。为防止新设备腐蚀,延长其使用寿命,并对生产实际中已经发生的腐蚀破坏事故进行研究,已成为当前迫切需要解决的问题。本文针对某化工厂合成氨脱碳系统中变煮沸器不锈钢列管腐蚀类型及腐蚀穿孔的原因进行了分析论证及试验研究。为证实渴液爆沸对列管的腐蚀,在高温下的     

一种修复换热器列管的焊接方法

一种修复换热器列管的焊接方法在中、小型硫酸生产过程中，往往由于指标控制不严，换热器列管因酸雾或原始水份超标而严重腐蚀穿孔，导致转化率降低。为了不影响生产，过去，我们采用铁片堵焊列管的方法，即将腐蚀穿孔的一段列管割去，再用铁片将管口堵焊起来。这种方法在...     

二氧化碳汽提塔列管腐蚀速率高的分析和对策

通过对二氧化碳汽提塔换热列管腐蚀情况的分析研究，判断腐蚀增速原因为高压系统氧含量偏低、氨碳比偏低、系统水碳比偏高、汽提塔加热蒸汽压力偏高、汽提塔列管进料不均等，从工艺条件及设备局部更新两方面采取相应解决措施，减缓了汽提塔列管腐蚀速率，延长了汽提塔使用寿命。     

240m^2废热锅炉的改造

公司现有18台Φ 650造气炉，与之配套的废热锅炉(240m^2，DN1800)为列管式余热锅炉。在运行过程中，由于半水煤气中携带有大量煤末，对半水煤气进口侧列管冲刷腐蚀较严重，时间一长很容易将列管管壁磨穿，造成蒸汽进入管程。当蒸汽进入管程后，半水煤气中夹带的煤末遇到高温蒸汽极易凝结成块，造成大面积列管堵塞，不但使系统阻力增加，而且大大降低了换热面积，造成大量热能浪费。针对上述实际情况，对废热锅炉进行了如下改造，收到了较好的效果。     

尿素高压热交换器列管腐蚀与检测

介绍尿素高压热交换器列管的腐蚀规律和特点，指明列管腐蚀检测的重点。     

氨汽提塔列管腐蚀减薄原因分析及处理措施

检测了氨汽提塔列管腐蚀状况,分析了列管腐蚀原因,并进行强度核算,对氨汽提塔调头后列管缺陷进行处理.     

氯化铵外冷器腐蚀分析及防腐蚀涂层保护

联碱生产中氯化铵外冷器列管腐蚀最为严重，腐蚀主要集中于管端。本文作者王敏主要对点蚀、缝隙腐蚀、湍流腐蚀及空泡腐蚀等几种腐蚀类型进行了分析。在此基础上介绍了用环氧-酚醛复合涂层对其进行保护的具体方法，包括列管内外壁、管端、管板的防腐蚀设计和供烤温度的控制等。     

焦化加热炉炉管失效分析

应用扫描电子显微镜、能谱分析以及X射线衍射仪对焦化加热炉炉管的高温腐蚀形貌,腐蚀物成分以及物相进行了分析,结果表明,尽管加热炉管用材是抗腐蚀性能和高温机械性能均良好的Cr5Mo钢,但由于炉膛操作温度过高,且燃料中含硫,炉管不但发生高温氧化腐蚀,还发生硫化腐蚀,使破坏加速,最终导致炉管失效。提出了预防措施。     

重防腐HLX-05涂料性能研究

针对井下油管的腐蚀环境,研制了HLX-05重防腐涂料。对其进行性能评价表明:HLX-05重防腐涂料具有优异的耐盐雾腐蚀、耐酸腐蚀和耐油田污水腐蚀等耐腐蚀性能,并具有良好的综合性能,可以满足不同腐蚀环境条件下防腐的涂覆需要。在高温高压下,仍具有较好的耐H2S/CO2腐蚀和耐碱腐蚀的性能。     

新型转化炉炉管的开裂原因分析与防护

针对典型的制氢装置转化炉炉管,阐述了转化炉炉管的腐蚀介质及原因,提出了高温蠕变、高温氧化、应力腐蚀、渗碳和脱碳以及氯离子腐蚀是造成转化炉炉管开裂的主要原因.控制原料气中氯离子含量,选择适宜的过渡段炉管材质以及严格控制转化炉运行参数,可使腐蚀得到控制.     

High temperature corrosion of boiler waterwalls induced by chlorides and bromides. Part 1: Occurrence of the corrosive ash forming elements in a fluidised bed boiler co-firing solid recovered fuel

In waste fired boilers high temperature corrosion has often been attributed to zinc and lead chlorides. In addition, bromine induced high temperature corrosion has been earlier observed in a bubbling fluidised bed (BFB) boiler co-firing solid recovered fuel (SRF) with bark and wastewater sludge. In Part 1 of this work a measurement campaign was undertaken to determine the occurrence of Cl, Br, Zn and Pb in the fuel, in the combustion gases as well as in the deposits on the boiler waterwalls. It was observed that Cl, Br, Zn and Pb originate to a large extent from the SRF, they are vaporised in the furnace, and may form waterwall deposits. This, complemented by fluctuations between oxidising and reducing atmosphere resulted in rapid corrosion of the waterwall tubes. Concentrations of Cl, Br, Zn and Pb in the fuel, in the furnace vapours and in the deposits are reported in this work. As there is lack of published data on the bromine induced high temperature corrosion, laboratory scale corrosion tests were carried out to determine the relative corrosiveness of chlorine and bromine and these results will be reported in Part 2 of this work. Furthermore, the forms of Cl, Br, Zn and Pb in the combustion gases as well as in the waterwall deposits were estimated by means of thermodynamic equilibrium modelling and these results will also be discussed in Part 2.     

开车用加热炉炉管腐蚀分析

对一台开车加热炉炉管的外壁腐蚀失效的原因进行了探讨，认为其外壁主要是发生了高温下的硫化－氧化腐蚀和闲置过程中的硫酸再生循环腐蚀。前者为轻微的均匀腐蚀，对炉管的使用寿命影响不大；而后者则导致炉管外壁形成大量局部腐蚀凹坑，严重影响了炉管的继续使用。     

Experimental study of complex two-phase instabilities during the start-up of a vertical thermosyphon reboiler operating under vacuum

This paper reports experimental studies of the start-up at reduced pressures (0.105–0.171 bar) and low heat fluxes (1.23–1.55 kW m⁻²) of the thermosyphon reboiler research facility in the Morton Laboratory at the University of Manchester. This is a full scale replica of an industrial sized natural circulation thermosyphon reboiler comprising 50 vertically mounted 25 mm OD tubes of 3 m length with water as the process fluid in the tubes and with steam condensing in the shell side of the reboiler. Unstable behaviour is obtained at start-up with flow-induced instabilities (geysering) when the level of the liquid within the tubes of the bundle is up to the top tubesheet (100% submergence) and also at 83% submergence of the tubes irrespective of the process pressure. At 100% submergence of the tubes, intermittent reversed flows in the entire loop with substantial vibrations are obtained. Chaotic behaviour is obtained at the lower submergence level of 83%. However, start-up at process pressures of 0.22 and 1.04 bar, and low heat fluxes with the entire thermosyphon loop flooded with liquid completely alleviated the flow-induced instabilities observed at the lower submergence levels within the tubes. The flow in the closed loop of liquid is induced very soon after the steam is introduced into the reboiler due to the buoyancy forces emanating from differences in density around the loop. The start-up is smooth and relatively quick, but further instrumentation and control are required for the introduction of the feed to the thermosyphon system once vapour is generated. A control strategy and procedure is proposed which will avoid the instabilities that inherently occur with start-up procedures currently practised in industry.     

Use of Wire Matrix Inserts in Thermosiphon Reboilers in the Lower Operating Range

Turbulators are applied to increase the thermal efficiency of heat transfer units. The additional pressure drop can be challenging for the self-circulation of thermosiphon reboilers. Thus, the effects of hiTRAN®-wire matrix inserts for the boiling of water and a water/glycerol mixture were investigated herein, using the performance of a thermosiphon reboiler with plain tubes as a reference. The reboiler was operated at sub-atmospheric pressures, small driving temperature differences, and under flooded conditions. Favorable and unfavorable operating conditions for using inserts were specified. Especially for the water/glycerol mixture, significant improvements of self-circulation and heat transfer up to six times compared to the plain tube reference were observed, allowing an operation of thermosiphon reboilers at smaller driving temperature differences under sub-atmospheric pressures.     

高沸点差热敏性物系精馏塔再沸器流程布置研究

研究双酚Ａ生产工艺中母液浓缩塔塔釜再沸器的流程布置，建立了母液浓缩塔的数学模型。研究结果表明，对高沸点差热敏性物系的精馏，在设计塔釜再沸器流程时，要注意循环液量对再沸器出口物料温度的影响。     

用AspenPlus模拟分析和优化多晶硅合成工段洗涤塔

利用AspenPlus模拟分析了三氯氢硅合成洗涤塔,利用灵敏度工具分析了摩尔回流比对洗涤塔操作的影响,还利用优化分析工具对进料温度进行了分析。经对洗涤塔的模拟分析,建议实际运行采用适宜的较小回流比操作,可提高氯硅烷的回收率,还可降低再沸器的供热,甚至可取消它,有效避免硅粉和金属氯化物对其的严重磨蚀和腐蚀,同时还可减少冷凝器所需的冷量,降低多晶硅生产中的操作成本。     

Active Corrosion of Sintered α-Silicon Carbide in Oxygen–Chlorine Gases at Elevated Temperatures

The active corrosion of sintered α-silicon carbide from heat exchanger tubes in the temperature range 900° to 1100°C in gas mixtures containing 2% Cl₂ by volume with additions of O₂ or H₂ has been investigated by thermogravimetric analysis and subsequent examination of the corrosion products. The presence of a small amount of oxygen accelerated rapid active corrosion in chlorine-containing gas mixtures, but the corrosion was suppressed by an active-to-passive transition when the concentration of oxygen in the gas mixture was too high. Low rates of attack were observed in the environments containing H₂ even when the chlorine potential was high. The concentration of oxygen necessary to produce the active-to-passive transition was found to vary from one material to another and may be related to the amount of excess carbon in the sintered silicon carbide.