液力变矩器故障分析及使用维护

尿素生产中,用液力变矩器无极调节甲铵泵的转速来改变甲铵泵流量,以达到调节一段吸收塔液面的目的。国产甲铵泵用变矩器,一般是单级离心正转可调式变矩器,具有传动效率高,传动平稳,工作机与原动机软连接,可无极变速等优点。但液力变矩器较一般传动机械精密,结构复杂,加工工艺复杂,须精心维护和检修。现就液力变矩器常见的故障及维护检修中一些问题加以讨论。     

提高3W-J1型一段甲铵泵运行周期的措施

一段甲铵泵是水溶液全循环尿素生产流程中的关键设备之一。我公司一甲泵为3W J1型卧式三联柱塞泵,自投运以来,运行情况一直不理想,先后对该泵进行多次改动:泵的填料改为TFA;出口安全阀改型;变矩器改为手动操作;液力变矩器冷却器扩容;泵体镗缸处理;变频改造;等等。这些措施的实施,改善了一段甲铵泵的运行情况。但随着生产负荷的加大,一甲泵出现了不少问题,运行周期一直上不去。(1)打量不好,导致运行周期短,最长运行周期为1个月左右;(2)联轴器不可靠,多次因联轴器销子断而停止运行;(3)填料函与泵体联结处易泄漏;M SizedNitrogenousFer…     

中压变频调速节能装置在赤天化液氨泵的应用

高压液氨泵是化肥生产企业的关键设备,而其原有的调速系统均为老式的液力变矩器调速系统,成本高,维修困难。本文论述了高压液氨泵的变频调速系统,并将此系统成功应用于赤天化,并取得了非常好的效果。     

交流变频调速在我厂的应用

我厂尿素装置高压甲铵泵先后使用过整流子电机、液力耦合调速器等方式调速,均存在效率低、调速性能差、维护检修频繁等问题。后来,我们选用了变频器调速(VVVF)对尿素装置甲铵泵电机调速进行改进,效果极好。现将情况简介如下。1　各种电气调速方式优缺点比较直流机曾以其优良的调速性能而一度占据调速系统的统治地位,但由于下列原因而使它的应用受到局限:(1)直流电机结构复杂,价格昂贵;(2)在易燃易爆及恶劣的环境下不宜使用;(3)由于存在换向器及电刷,维护维修困难,费用也高;(4)电机转速及容量受到限制。交流调速具有以下优点:(1)单机容量大…     

离心式高压甲铵泵的改造与检修

介绍离心式高压甲铵泵的结构特点以及出现的事故及原因分析，着重介绍从设备角度进行的改造和检修情况，提出泵在检修维护中应注意的问题     

高速离心式甲铵泵应用情况总结

介绍高速离心式甲铵泵的操作和维护检修情况，对该泵有关技术改造和存在的问题进行总结。     

高速主式甲铵泵应用情况总结

介绍高速离心式甲铵泵的操作和维护检修情况，对该泵有关技术改造和存在的问题进行总结。     

高压液氨泵增设液力变矩器装置的可行性

高压液氨泵增设液力变矩器装置的可行性陈铁武（江西江氨化工有限责任公司南昌市３３００１２）高压液氨泵是尿素装置的主要传动设备之一，其作用是将液氨由１．７ＭＰａ增压到２０ＭＰａ（表）后送入尿素合成塔。入塔氨量根据尿素生产负荷进行调节，高压液氨泵出口多出的...     

G150变频器在高压甲铵泵调速系统中的应用

详细叙述了甲铵泵调速系统电气变频节能改造的全过程。通过西门子G150变频器在改造中的应用,不仅解决了原泵变矩器备件购买和维护困难等问题,而且操作维护也比较方便。经过改造前后相同工况下负荷参数的对比及测算,本次改造到达了节能降耗的目的。     

液力偶合器在石油钻探领域的应用分析

本项目针对传统机械钻机液力变矩器传递效率低、燃油消耗高等主要缺点,应用效率较高的液力偶合器替代液力变矩器,从而提高柴油机输出功率,减少燃油消耗,实现节油减排的目标。     

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。     

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.     

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。     

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.