三废余热锅炉过热器爆管的探讨与改造

湖北潜江某企业投运的1台Q190／900-60．3．82／450型（60t／h）三废混燃隧道式余热锅炉为卧式布置、采用单锅筒纵置式的自然循环水管锅炉，含尘烟气从锅炉入口进入，依次流经水冷屏、过热器、对流管束、省煤器、空气预热器后排出炉外。过热器采用悬吊式结构，高温过热器蛇形管为12CrlMnVG锅炉管（GB5310），低温过热器蛇形管采用20锅炉管（GB3087），顺列布置，采用喷水减温器进行减温。     

对硫酸余热锅炉进行技改的体会

介绍了与40kt/a硫酸装置配套的F101—5/39—450型余热锅炉的技术改造。通过对沸腾炉内换热管喷涂金属粉末,防止了换热管的磨损爆裂;在余热锅炉的二、三烟道砖隔墙上加焊夹角为30°的顶板,使矿尘迅速滑落,不致堆积;提高四烟道的温度并加强密封,减少了蒸发管的低温露点腐蚀;改进面式减温器结构,使分水均匀,避免了过热器爆管。     

120kt／a硫铁矿制酸系统余热锅炉泄漏原因分析

1 概况 我厂硫酸五系统设计能力为120kt/a,以硫精矿为原料,湿基含硫35％～42％。余热锅炉型号为F101—20/39—450。锅炉本体为强制循环,沸腾炉内冷排为自然循环。本体共四个烟道。呈W形,高、低温过热器布置在一烟道,减温器为混合式。吨酸发汽量稳定在1.1t左右。锅炉几何尺寸与运行参数详见表1、2。     

余热锅炉蒸汽过热器故障分析和改造

<正>云南玉溪银河化工有限责任公司(以下简称银河化工公司)的合成氨装置采用煤球为原料的固定层间歇气化工艺。2009年,为了节能降耗,投运1台55 t/h三废混燃流化床余热锅炉。该锅炉以造气炉产生的废渣、废灰、废气(造气吹风气、提氢后的合成放空气)为燃料,设计产生压力3.8 MPa、温度520℃的蒸汽。蒸汽过热器设有高温段和低温段,采用蒸汽过热器喷水调整蒸汽温度。由于蒸汽用户不需要高温蒸汽,后将蒸汽过     

200kt/a硫酸余热锅炉设计安装概要

硫酸生产中,余热锅炉是关键设备之一。杭州锅炉厂针对我国目前硫酸生产中焙烧炉矿料品位变化大、装置生产负荷变化大、炉气含尘高、腐蚀性大的特性,在总结F101锅炉过热器爆管频繁、炉气偏流或短路影响传热效果等经验与教训的基础上,重新设计制造了为200kt/a硫酸装置配套的QCF50/925—30—3.82/450余热锅炉。在设     

采用气能激波旋转吹灰器解决余热锅炉积灰问题

广东省某水泥厂4 500 t/d生产线配套9 MW纯低温余热发电,所配套余热锅炉设计进烟风温度550 ℃,过热器出口设计烟温310 ℃,额定蒸汽量20 t/h,进口蒸汽温度210 ℃,出口蒸汽温度450 ℃。设备投运2年以来,窑头过热器（型号为170AY01-2-1-0）积灰非常严重,该过热器有上下两层受热面,下层为光管,上层为鳍片管。运行2年半后,烟气温度因为积灰提高了15 ℃。每次停炉检查都需要人工清理。图1为运行2年半后的光管和鳍片管的积灰情况。     

电站锅炉低温过热器管失效分析

针对一台煤粉锅炉低温过热器管爆管的事故,通过对事故过热器管的宏观观察、材质分析及金相检查,以及对该台锅炉燃用的煤种和运行负荷的分析了解,对该起锅炉爆管事故进行了原因分析,提出了该锅炉的运行优化方案,对同型号锅炉的安全可靠运行和检验提供了参考     

12Cr1MoVG锅炉高温过热器管爆管事故分析

通过宏观分析、材质分析和金相测量等方面对12Cr1Mo VG锅炉高温过热器管爆管事故进行失效分析。分析其失效机理并提出解决措施。结果表明,由于锅炉长期超温运行,致使过热器管材料性能下降。导致过热器管发生蠕变胀粗,外壁氧化,管壁减薄,最终致使发生爆裂事故,应对该锅炉的高温过热器管进行更换。     

1000MW超超临界锅炉低温过热器爆管原因分析

通过爆口宏观形貌分析、氧化膜堆积量射线检查、样管基体的化学成分及硬度检测、样管内壁氧化膜微观形貌及成分分析、氧化膜脱落失效机理分析,对某发电公司1000MW超超临界锅炉低温过热器爆管原因进行了深入研究。结果表明：低温过热器垂直段下弯头氧化膜堵塞引起短时过热爆管;样管完全满足国家标准或行业标准对12Cr1MoV钢的化学成分及硬度要求,低温过热器当量金属温度也远低于低温过热器壁温设计值和12Cr1MoV的抗氧化温度;大容量锅炉低温过热器管壁厚、热应力大和大容量锅炉蒸汽流速大、扰动强度高等因素共同导致氧化膜临界脱落厚度远小于小容量锅炉同管材氧化膜正常脱落厚度,增大了低温过热器氧化膜堵塞爆管的概率;在一定区域内低温过热器壁温沿炉膛宽度方向分布为中间壁温低、两侧壁温高,两次低温过热器爆管位置均在壁温最高区域,壁温高也增加了氧化膜生成速率和爆管的概率。研究结果还表明：样管内壁氧化膜有明显分层现象,由外到内分别为Fe₂O₃层、Fe₃O₄层和富Cr氧化物层等3层,晶粒尺寸由外层至内层逐渐减小,表面结构由外层至内层逐渐致密。     

锅炉高温过热器管爆管事故分析

本文通过对锅炉高温过热器管爆管的检验与分析,找出爆管原因,提出防止锅炉高温过热蒸汽管爆管的措施。     

Metabolism of trideuterated iso-lignoceric acid in rats in Vivo and in human fibroblasts in culture

Saturated very long chain fatty acids (fatty acids with greater than 22 carbon atoms; VLCFA) accumulate in peroxisomal disorders, but there is little information on their turnover in patients. To determine the suitability of using stable isotope-labeled VLCFA in patients with these disorders, the metabolism of 22-methyl[23,23,23-²H₃]tricosanoic (iso-lignoceric) acid was studied in rats in vivo and in human skin fibroblasts in culture. The deuterated iso-VLCFA was degraded to the corresponding 16- and 18-carbon iso-fatty acids by rats in vivo and by normal human skin fibroblasts in culture, but there was little or no degradation in peroxisome-deficient (Zellweger’s syndrome) fibroblasts, indicating that its oxidation was peroxisomal. Neither the 14-, 20-, and 22-carbon iso-fatty acids nor the corresponding odd-chain metabolites could be detected. In the rat, the organ containing most of the iso-lignoceric acid, and its breakdown products, was the liver, whereas negligible amounts were detected in the brain, suggesting that little of the fatty acid crossed the blood-brain barrier. Our data indicate that VLCFA labeled with deuterium at the ω-position of the carbon chain are suitable derivatives for the in vivo investigation of patients with defects in peroxisomal β-oxidation because they are metabolized by the same pathways as the corresponding n-VLCFA. Moreover, as iso-VLCFA and their β-oxidation products are readily separated from the corresponding n-fatty acids by normal chromatographic procedures, the turnover of VLCFA can be more precisely measured. A preliminary report of part of this work (Reference 18) was presented at the 5th International Symposium on the Synthesis and Applications of Isotopes and Isotopically Labelled Compounds, Strasbourg, France, June 20–24, 1994.     

佛山市顺德新城区降水中污染物的监测和分析

为掌握佛山市顺德新城区降水中污染物的情况,2015年7月至8月,文章作者分别在雨天进行了降水取样,对降水中的pH、电导率、常见阴离子(F-、Cl~-、NO_3~(2-)、SO_4~(2-))及部分重金属(铅和镉)进行监测分析。选择有相关数据的珠江三角洲和石家庄、厦门等地的降水中污染物的情况进行对比。结果表明,顺德新城区降水中的p H和部分阴离子浓度优于珠江三角洲平均值,酸雨类型属于硫酸和硝酸混合型;其水体洁净程度略差于石家庄;铅和镉的浓度也高于厦门,甚至部分超出了人体能直接接触的安全范围。     

Denitrification in shallow groundwater in a coastal agricultural area in Japan

In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L^–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L^–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO₂ L^–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site.     

我国硝酸工业生产技术新进展

系统叙述了我国硝酸工业2000-2007年生产现状及主要技术成果,尤其指出了国产"四合一"机组的成功投运,使我国硝酸国产化装置取得较大的进步,表现在吨酸的铂耗、氨耗和能耗等方面接近国外引进装置水平,同时介绍了国外双加压法硝酸生产技术的进展.我国已成为硝酸生产大国,仍需以先进的技术改造和发展我国硝酸工业,确保我国硝酸工业健康有序地发展,加快从硝酸生产大国向强国迈进的步伐.     

高效液相色谱法分析化妆品中微量成分的研究进展

综述了高效液相色谱法在化妆品中防腐剂、防晒剂中紫外线吸收剂以及性激素的检测等几个方面的应用;同时,介绍了分析所用的色谱柱、流动相、使用的检测手段以及样品的提取方法;最后针对目前存在的问题,提出了高效液相色谱用于化妆品中微量成分分析的研究方向和发展前景。