空分装置发生晃电事故的分析及处理

本文简要介绍了空分装置发生晃电事故的影响,提出了详细的处理方案,通过晃电事故方案使空分装置达到安全停车效果,本着最大程度保护设备安全考虑,对空分装置发生晃电事故后影响进行了分析,并做出了处理方案.     

避免“晃电”影响低压供电系统运行的措施

针对"晃电"影响低压供电系统稳定运行的问题,采取了以下措施:为关键设备增加不间断电源装置(UPS);增设防"晃电"保护单元,并与UPS组合使用;对UPS装置增加双电源及检修电源。改造后,"晃电"造成的事故明显减少。     

抗晃电技术在石化企业中的应用

为了减小晃电给石化企业带来的不良影响,提出了不同的抗晃电措施。通过各种措施的相互配合,从技术层面保证了被保护设备晃电时的稳定性和晃电后自动恢复的能力,为装置长周期稳定运行提供了保障。     

优化电气控制装置,降低“晃电”对生产系统的危害

介绍了化工生产装置中转机设备的配电装置接触器在系统晃电时动作造成设备跳车,进而引起关键设备跳车造成化工生产装置停车或局部停车,进而导致生产工艺过程紊乱,因此针对不同设备进行了改造,使其在晃电时能自动恢复或通过延时躲过晃电时段,保持系统正常生产。     

晃电事故对循环流化床锅炉运行的影响与对策

结合生产运行实际,分析了晃电事故对循环流化床锅炉正常运行的影响,并分多种具体情况,对如何应对、避免晃电事故扩大化进行了探讨,对同类型装置正确应对晃电事故具有一定的借鉴意义。     

风机变频器抗“晃电”技术改造

针对甲醛生产装置中罗茨鼓风机变频器遇"晃电"跳车的问题,通过采用DZQ-B抗"晃电"技术,结合变频器"再启动"功能对控制回路进行改造。实际运行表明能够有效解决供电系统"晃电"对变频器造成的影响,保证装置的安全稳定运行。     

如何避免电厂重要辅机系统脱网而造成发电机组停机事故发生研究

目前多数企业配电网实际供电可靠性无法满足某些负载连续生产性需求,一旦电网电压波动即晃电,从而引起的生产装置跳车问题越来越突出,各企业深受其害。各大企业都有晃电后确保装置安全停车预案,并耗费大量人力物力进行演练,确保晃电后生产装置能安全停车并重新开车,避免晃电后次生灾害的发生,但这不是根本解决办法。     

晃电停机的解决方案

分析了在生产中晃电产生的原因及危害,并介绍了FZQD—III型电机分批再起动装置特点、工作原理、技术性能指标及应用情况,该晃电起动装置对化工生产企业连续运转具有积极和推广作用。     

防晃电技术及其在石化行业中的应用

由于石化行业具有工艺复杂,技术密集,高温高压和连续生产的特殊性质,针对其供电系统发生晃电时带来的不良影响,必须采取有效的防晃电技术来解决问题。为此,在重点分析晃电产生的原因、对供电回路的影响后,对5种常见防晃电技术的优、缺点进行了分析比较。最后介绍某石化企业在炼油区的几套关键装置上采用再启动控制器实现相关设备的晃电再启动的应用情况。     

浅析化工企业晃电治理与供电系统升级改造

通过案例剖析化工供电系统电网故障晃电对化工企业安全生产的影响和危害，分析基于瞬时电压暂降和瞬时电压中断引发装置连续性生产流程中断的根本原因，据此提出从电源侧到负荷侧晃电治理的基本思路与对策。双电源供电系统采用快速切换技术取代传统备自投装置，缩短备用电源投入时间；负荷侧由电气和工艺等跨专业协同配合，对高、低压电机及变频器等电压敏感设备，分类实施晃电抑制措施。为消除历史遗留的技术缺陷与安全风险，全面提升装置晃电治理能力，解决系统性关联问题，对企业供电系统优化升级改造提出统筹规划建议。     

少烟三元乙丙橡胶材料研制

以三元乙丙橡胶(EPDM)为基体材料，三氧化二锑、十溴苯醚为阻燃剂制备了材料配方，试验了三氧化二锑(Sb22O3)、十溴苯醚(DBDPO))配比对材料烟雾和力学性能的影响，测试了材料的氧指数，可见光的透过率，自熄性等。结果表明，DBDPO与EPDM的相容性比较好，Sb2O3的相容性则相对比较差，两者都可以提高材料的阻燃性能。以4045EPDM橡胶为基体材料，当EPDM100g，白炭黑10g，二硫化四甲基秋兰姆(TMTD)2g，ZnO5g，促进剂M1g，硬脂酸2g，硫磺3g，Sb2O3和DBDPO质量比为20．0／40．0，可以获得具有较好力学性能的少烟EPDM橡胶材料。     

Effectiveness in the Removal of Organic Compounds from Municipal Landfill Leachate in Integrated Membrane Systems: Coagulation – NF/RO

The article presents the results of studies concerning the hydraulic permeability of integrated membrane systems during the treatment of municipal landfill leachate. The laboratory-scale experiments were conducted to determine the effectiveness of coagulation as a pretreatment option for treating stabilized landfill leachate and effectiveness of nanofiltration (NF) and reverse osmosis (RO) processes. The municipal landfill leachates were analyzed for the concentration of the following: polycyclic aromatic hydrocarbons (PAHs), nitrate nitrogen, ammonium nitrogen, chemical oxygen demand (COD), total organic carbon (TOC), total carbon (TC), suspended soils (SS), turbidity, pH. The commercially available coagulant – aluminum sulfate Al₂(SO₄)₃·18H₂O (alum) was used as a coagulant. The NF process was carried out at the transmembrane pressure of 1.5 MPa. The membrane separation process was based on a thin film membrane (DK). The transmembrane pressure of the RO stood at 2 MPa and for this process one polyamide membrane (AG) was used. The level of leachate treatment was defined for raw and cleaned wastewater indicators. Both NF and RO membranes allowed obtaining the high level of pollutants removal. In the coagulation–NF system, the removal efficiency was equal to 77% for PAHs, 88% for COD, 72% for ammonium nitrogen, 80% for nitrate nitrogen, 67% for TOC, 80% for TC, 96% for SS and during the RO – 86% for PAHs, 98% for COD, 93% for ammonium nitrogen, 87% for nitrate nitrogen, 89% for TOC, 100% for TC, 98% for SS. The calculations based on the assumptions of the mathematical filtration model (relaxation) made it possible to predict the efficiency of commercial filtration membranes used for leachate treatment.     

丙型肝炎病毒核心总抗原检测试剂的评价

目的评价国外丙型肝类病毒核心抗原检测试剂盒的质量以及窗口期检测核心总抗原(HCVcAgTrak-C)的意义。方法用该试剂检测8649份自然献血员及566份HCV可疑感染者血清的核心总抗原,并与抗体试剂(Anti-HCV)、游离抗原(HCVfreeAg)试剂、核酸(HCVRNA)试剂进行比较。结果筛出核心总抗原和抗体同时阳性血清152份,抗体阴性而总抗原阳性血清5份。利用RNA试剂检测这5份血清,结果HCVRNA阳性。利用HCVfreeAg试剂检测这9215份血清,发现2份阳性,其中1份为抗原和抗体同时阳性,RIBA检测确证这份血清产生的是核心区抗体。另1份为单独抗原阳性。结论在应用HCV抗体试剂对血液进行筛查的同时使用HCVcAg试剂检测,可以减少因窗口期造成的漏检。     

Reactive separation of dilute ethylene by hydroformylation using slurried rhodium catalysts on phosphinated resins and silica

A series of slurried rhodium catalysts on phosphinated resins and silica were tested for the reactive separation of dilute ethylene by hydroformylation to propanal. The amount of rhodium leaching was determined for most of the systems investigated. Leaching ranged from <2 to 11% for catalytic runs for resin supported systems, but was found to be much more significant for the phosphinated silica system studied, 19%. The level of rhodium leaching correlated well with the loss in rate of propanal formation between repeated experiments using recycled catalysts for the resin based systems, but the loss in rate was much more significant for the silica based system. This level of leaching is very high for a commercial process for basic chemical synthesis, for which leaching is typically at the ppb level. Rates of propanal formation for resin supported catalyst systems correlated well with the cone angle of the free phosphine, with rates as high as 0.35 mol/l/h. However, while smaller cone angles were found to be directly proportional to rate, supported systems were less active than homogeneous counterparts.     

国内甲醇消费市场状况

我国甲醇主要用于甲醛、对苯二甲酸二甲酯、农药、甲基叔丁基醚、醋酸的生产,我国甲醇消费量增长最快的领域将是燃料甲醇、醋酸和甲醛。预计 2005年甲醛对甲醇的需求量为 175万t左右,聚甲醛对甲醇的需求量为 40万t,醋酸需求甲醇为 62万t,甲基叔丁基醚为 46万t左右,甲胺为 30万t,碳酸二甲酯为 11万t,甲烷氯化物为 10万t,甲醇燃料为 80万t,农药为 22万t,对苯二甲酸二甲酯 3 0万t,其他衍生物 27万t。     

Mathematical Modeling and Simulation of Drying Using Two Industrial Concurrent and Countercurrent Rotary Dryers for Ammonium Nitrate

Drying of ammonium nitrate (AN) is accomplished in the Shiraz Petrochemical Complex (SPC) using a concurrent rotary dryer following a countercurrent rotary dryer. A mathematical model for these rotary dryers including heat and mass transfer was developed. The model was checked against industrial-scale data, which showed a good agreement. The average absolute deviation of the simulation results compared to the industrial data for the concurrent dryer was 4.0% for solids moisture, 1.3% for solids temperature, and 1.8% for air temperature and for the countercurrent dryer it was 9.0% for the solids moisture, 2.0% for solids temperature, and 4.6% for air temperature. These simulation results reveal that for outlet solid moisture, inlet AN moisture, and air temperature as well as the outlet temperature of product, the inlet solid and air temperature have major effects for both concurrent and countercurrent flow.     

Analysis of Gas Centrifuge Cascade for Separation of Multicomponent Isotopes and Optimal Feed Position

Abstract

Analysis of the concentration distribution in a gas centrifuge cascade for separation of multicomponent isotope mixtures is different from that in a cascade for separation of two-component mixtures. This paper presents the governing equations for a multicomponent isotope separation cascade. Numerically predicted separation factors for the gas centrifuge cascade agree well with the experimental data. A theoretical optimal feed position is derived for a short square cascade for a two-component mixture in a close-separation case. The optimal feed position for a gas centrifuge cascade for separation of multicomponent mixture is discussed.     

汽车工业用粘接材料的现状与展望

本文按照汽车制造工序介绍国外汽车工业折边用胶粘剂、点焊胶接用胶粘剂、车身密封胶、车身底涂料、窗玻璃用单组份湿气固化型聚氨酯胶粘剂以及纤维增强树脂用结构胶粘剂等主要胶种的最新技术发展动向。讨论了我国汽车工业用胶粘剂的现状和差距，提出几点建议。     

FULLY DEVELOPED LAMINAR CONVECTION FROM A HELICAL COIL

A general correlating equation has been developed for all Prandtl and Dean numbers. This expression was constructed by joining the theoretical Nusselt number for a straight tube, a theoretical asymptote for the regime of creeping secondary flow, a semi-theoretical expression for the boundary layer regime and an asymptotic value of Nu for the intervening regime of flow.The arbitrary coefficients and exponents in the model were evaluated using experimental and numerically computed values. Slightly differing sets of coefficients are required for uniform wall temperature and longitudinally uniform heating with uniform peripheral wall temperature.

All prior theoretical results were for toroidal flow (zero pitch). A numerical solution was developed for helical flow (finite pitch). These results confirm the validity of neglecting pitch for tightly wound coils but suggest a generalization of the correlating equation for large pitch.     

综合管廊中塑料管道支撑间距的确定

根据材料力学原理，结合塑料管道蠕变性能试验数据，给出了架空敷设塑料管道支撑间距的计算方法，并对硬聚氯乙烯（PVC?U）电力护套管和聚乙烯（PE）给水管的支撑间距进行计算，结果表明塑料管道满足综合管廊中架空敷设使用的要求，可为进一步研究塑料管道在水平架空敷设条件下长期性能及产品应用设计提供参考。