合成氨变换工段仪表选型与工程实现

为解决当前合成氨工程变换工段集中控制系统实现的主要障碍,无法对现场各环节运行参数进行精准监测的问题;在对合成氨变换工段控制系统工艺特点和工艺要求分析的基础上,结合实际生产需求重点完成了温度监测仪表、压力监测仪表以及流量监测仪表的选型;最后,对所选型仪表在DCS控制系统的应用效果进行评估,取得理想控制效果。     

提高仪表监测质量和监控水平实现装置仪表安全运行

高质量的仪表调节系统是装置安、稳、长、满、优运行的有力保障。装置班组操作人员以及工艺技术人员作为非仪表专业人员,对所在装置所有仪表负有操作责任的同时,同样具有监测和控制的义务。提高仪表监测质量和监控水平,就是为了增加装置运行仪表的可信度,究其工作中心点是确保各在线使用仪表的可用、可信、可控,     

采油厂自控监测仪表运行的影响因素分析

自控监测仪表是采油厂工作的重点,以现阶段采油厂工作情况为基础,结合近年来自控监测仪表工作特点,明确其工作的意义和内容,分析采油厂自控监测仪表正常运行的影响因素,提出符合工作需求的解决方案,以此为采油厂的发展提供保障。     

红外热象仪对大化肥装置高压渣油气化炉的监测

介绍高压渣油气化炉炉温监测仪表红外热象仪的工作原理、组成和监测实例，并对此仪表的干扰因素ε提供了详细的去除办法。     

大型压缩机机组仪表的现场检修

大型压缩机组仪表检修是整个机组检修的重要部分,针对机组仪表检修的相关问题与注意事项,阐述了机组状态监测仪表的拆除、检查、校验和回装过程。     

仪表控制盘电源供电方式的改造

文章介绍了仪表控制盘供电电源回路原设计中存在的问题及改造技术。通过对仪表控制盘供电电源回路的改造,使仪表供电电源回路达到了冗余备用状态,为仪表控制、监测回路的安全、稳定运行提供了保障。     

仪表速率报警在过程控制中的应用

基于霍尼韦尔DCS系统在实际生产中的常规报警在过程监测与控制中存在的不足,利用其系统内嵌的速率报警模块对关键设备的运行监测和重要仪表,增设仪表速率报警来强化生产管理具有重要意义。     

关于自来水厂污泥系统在线仪表选用及合理运行的探讨

自来水厂对于污泥处理中排放水的监测要求越来越高。文中概述了上海市自来水奉贤有限公司第二水厂污泥系统的情况,介绍了污水综合排放标准及相关要求,并选用适应运行工况的相关在线监测仪表,探讨了在线仪表的合理运行。     

化工仪器仪表及自动化装置维护检修规程

这是化工部化肥司给仪表工人编写的仪器仪表维修手册,分常规仪表、智能仪表、分析仪表、旋转机械状态监测仪表、探伤仪器五部分,共有340种仪器仪表。全书分上、下两册,约200万字。每个分规程内容重点     

论化工仪表常见故障原因与检修方法

随着化工生产自动化水平的提高,越来越多的化工仪表被用于生产中,对设备和原料的数据进行实时监测,化工设备越来越智能化。对化工设备故障进行分析,探讨仪表发生故障的原因,并提出化工仪表检修方法。     

Theory of thermohydrodynamic instability of the front of filtration combustion of gases

Based on the filtration equations with account of heat transfer in the heating region, the problem of instability of small perturbations of the wave front of filtration combustion of a gas is solved. Expressions for the growth decrement and critical transverse size of a perturbation are obtained. The problem of the wave-front stability is solved with account of the macroscopic redistribution of filtration in the system. The solution includes macroscopic characteristics such as the transverse size, the width of the high-temperature zone, etc. A method is proposed for taking into account the influence of the characteristics of the system on the evolution of perturbations. It is shown that small deformation perturbations of the front always increase to a certain amplitude; their subsequent development— continuation of their growth or stabilization—is determined by the characteristics of the system. Translated fromFizika Goreniya i Vzryva, Vol. 35, No. 5, pp. 3–5, September–October 1999.     

乙烯酮(双乙烯酮)下游产品废水的治理技术

乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。     

Implementation of the Results of Mathematical Modeling of Orientation of Polypropylene Fibre

Process schemes for implementation of the optimum conditions of the final stage of orientational drawing of PP fibre are proposed based on the results of mathematical modeling. The existence of successive stages of transformation of the structure of PP fibre in the second stage of orientational drawing was experimentally confirmed with indirect indexes. The necessity of selecting the draw ratio that ensures completeness of the given stage of structural transformation is demonstrated. Structural schemes are proposed for automated control systems for selecting the optimum draw ratio in the first and final stages of orientational drawing and control of the structure of the spun polymer with indirect parameters.     

三种煤样燃烧热的测定

本文通过三个厂家提供的三种煤样燃烧热的测定,由测定结果综合得出3号煤样燃烧最完全、燃烧热也最大,是三个煤样中最好的一种。     

A study of miscibility of blends of polybutadienes of varying microstructure

The miscibility of various amorphous polybutadienes with mixed microstructures of 1,4 addition units (cis, 1,4 and trans 1,4) and 1,2 addition units have been investigated. The studies here involved optical transparency, differential scanning calorimetry, and small angle light scattering. It was found that a 90 percent (cis) 1, 4 addition polybutadiene was immiscible with high (91 percent) 1,2 addition polybutadiene. Reduction of the 1,2 content to 71 percent induced an upper critical solution temperature (UCST) with the cis 1,4 polymer. Polybutadienes with 50 percent and 10 percent 1,2 contents were miscible above the crystalline melting temperature of the cis 1,4 polybutadiene. Immiscibility of the 91 percent 1,2 addition polymer was also found with a 10 percent 1,2 polybutadiene. The latter polymer also exhibits an UCST with the 71 percent 1,2 polymer. The results are used to interpret the characteristics of blends of polybutadienes of varying microstructure.     

Determination of the extent of oxidation of fats

Summary The amount of secondary oxidation products in refined and unrefined fats has been determined by reaction with benzidine acetate in iso-octane absolute alcohol solution, and measurement of the absorption at 350 mμ of the yellow color has been made. An “aldehyde value” has been calculated from this absorption intensity, using cinnamaldehyde as a reference substance. Determination of the aldehyde value and peroxide number of oils before and during refining has given information on the effect of the different refining processes on the state of oxidation of the oils. The effect of hardening on the content of oxidation products of an oil has been investigated. The effect of the amount of oxidation products in the unrefined material on the flavor stability of the refined material and of the margarine made from it has also been studied.     

Effect of Regime of Addition of Initiator on TEMPO-Mediated Polymerization of Styrene

Summary Investigation of the TEMPO-mediated polymerization of styrene at different regimes of addition of AIBN initiator showed that the course of the polymerization could be changed dramatically by a mode of the initiator addition without using any other additives. A very significant acceleration of the polymerization was reached at a specific regime without broadening the polydispersity of the resulting polymer.     

水泥水化热测定方法综述

水泥水化热是中、低热水泥和核电工程用水泥的一项关键的技术指标。全球范围内测定水泥水化热的方法有溶解法、直接法/半绝热法、等温传导量热法三种。本文总结了中、美、欧相关方法标准,对其测试原理、仪器设备、试验过程等方面进行了比对,并对其在领域的应用做了简单的概括。     

Interpretation of DSC measurements of the degree of fusion of rigid PVC

Differential scanning calorimetric (DSC) measurements can be used to infer the degree of fusion of rigid PVC articles. The preferred method involves annealing of the specimen at 260°C for 5 minutes, to erase all crystalline structures, followed by a 2 day storage at room temperature. New crystalline entities that are formed give use to an endotherm in the DSC heating mode. The magnitude of this endotherm divided by the total endotherm observed to 220°C can be used to estimate the degree of fusion of the specimen. Data from various processes and different cross-sections of extruded pipe are consistent with solvent resistance estimations.     

Effect of degree of deacetylation of chitosan on the kinetics of ultrasonic degradation of chitosan

The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003