新型现场监测换热器技术简介

1　概述循环冷却水系统的腐蚀、结垢和积污等问题往往通过水质配方加以控制和改善。为了监测不同药剂配方在循环水系统中的运行情况 ,在循环水系统的不同部位安装相应的现场监测换热器。现场监测用换热器是现场工艺换热器的一个缩影 ,它主要是用来跟踪、预测、判断水处理配方的运行效果、设备运行状况以及现场工艺运行情况 ,保证循环冷却水系统的优质运行。监测换热器使用效果的好坏及所测数据的真实性与其在现场安装的位置有直接关系 ,有 3种试验旁路流程可选择安装 :①紧靠凉水塔的循环水水泵出口处 ,直接由循环水泵出口向监测换热器供水 …     

循环水换热器强化检测在控制生产成本中的应用

本文详述了采用定点温度监测、定期分析取样、数据对比等循环水换热器强化检测手段在控制生产成本中的应用,通过循环水换热器强化检测,做到提前检查、预防性处理,提高循环水换热器的总体换热效果,并降低循环水换热器发生泄漏导致循环水系统污染的几率。     

监测换热器

监测换热器是对循环冷却水处理的运行监测和评价的重要手段,它可对循环水结垢、腐蚀进行综合监测和评价。因此广泛用于循环冷却水处理的现场监测。     

动力二车间循环水系统铁离子升高原因分析及对策

针对循环水中铁离子升高问题进行调查,通过对循环水系统相关设备的水质监测,查明换热器间歇性运行造成换热设备电化学腐蚀是铁离子持续升高的真正原因,进而采取在线清洗预膜、避免水滞留换热器等切实可行的解决方案降低系统铁含量.     

自动监测系统在循环水场的应用

在循环水场安装智能模拟监测换热器，这种换热器利用冷却水旁路，对其传热面下的腐蚀，结垢和积污情况进行监测，其监测结果，为循环水工艺调整和水质配方的筛选提供了依据。     

等压差调整降低循环水能耗的分析与实践

水的黏性是循环水流动产生阻力的根本原因,在工业循环水应用中,稳定流动状态下流经循环水换热器的流量与该换热器循环水进出口压差正相关。保持换热器前后循环水压差不变化,即可控制循环水流量不变化。本公司尿素循环水换热器位置高度低、但循环水回水压力高,造成水头的浪费。本次改造在保持尿素循环水供回水压力差不变的情况下,对尿素循环水供水压力和回水压力向下同幅度调整,经调整试验和对重点换热器进行比对,等压差调整供回水压力不影响系统运行流量、不影响关键换热器参数,为循环水泵的参数选取提供了保障,降低了系统运行能耗。     

化肥厂循环水系统不停车清洗探索

化肥厂循环水系统采用新型清洗剂FB-40进行不停车清洗,在清洗过程中对主要冷换设备的循环水出入口温度、二氧化碳温度等进行监测分析,清洗后对换热器内部进行检查,从监测和检查效果看,不停车清洗取得了较好的效果.     

循环水系统铜腐蚀原因分析与解决措施

河南神马尼龙化工公司循环水系统在日常监测时,发现铜挂片腐蚀速率达0.014mm/a,超标2倍;随后循环水水质恶化。经水质检测,挂片试验和对可疑换热器的重点跟踪,最后确定是由于2#己二胺E325换热器泄漏所为。在未确定原因之前,对循环水进行置换,投加铜缓蚀剂和加大投药量,减少加氯频率,可减轻循环水对设备的腐蚀程度。     

一循丙烯泄漏应急处置方法

第一循环水系统,因甲醇洗装置丙烯换热器泄漏,导致循环水CODcr、浊度、总铁突然升高,循环水呈黄褐色状,细菌量剧增,水质明显变差,换热效率降低。经过系统分析排查、微生物控制、采取性粘泥剥离、排污置换、持续监测等应急措施后,恢复循环水系统正常运行。     

炼油厂循环水系统粘附速率超标问题的解决

该炼厂西区循环水在系统扩建后出现了粘附速率超标问题,为解决这一问题进行了一系列的试验及现场处理工作。在循环水系统中,导致粘附速率超标的原因是多方面的,作者从气泡问题、排污措施及监测换热器等方面入手．进行了详细的分析,并综合其他因素,提出并实施改进方法,最终使问题得到了解决。     

阿司匹林系列综合性实验的教学改革

将以往实验教学中分散的、孤立的关于阿司匹林方面的实验加以总结和进一步延伸,使其系列实验内容涉及知识面较广、较深,涵盖的基本技能操作较全面,使之达到培养学生的综合能力、创新能力及提高综合素质的一项综合性实验。     

Model of Cellular Instability of Flames of Ternary Mixtures

A simple phenomenological diffusive-thermal model of cellular instability of premixed flames of ternary mixtures is developed and presented. The model shows that preferential diffusion can alter stoichiometry of the mixture, i.e., the ratio of the fuel and oxidizer concentrations, and also its effective dilution by an inert. Key parameters of the model are estimated using numerical modeling of burning velocities. Laminar burning velocities are calculated for hydrogen-oxygen-nitrogen, methane-oxygen-nitrogen, and propane-oxygen-nitrogen mixtures. Conditions for the appearance of cellular instability in ternary mixtures are determined and compared with experiments. In good agreement with experimental observations, the diffusive-thermal instability is predicted in hydrogen flames with equivalence ratios φ ≲ 1.45, in lean methane flames with φ ≲ 1.02, and in rich propane flames with φ ≳ 1.03. The magnitude of the change in the local flame velocity due to preferential diffusion is evaluated. It is demonstrated that nitrogen diffuses faster than oxygen in hydrogen-air and methane-air flames, while oxygen diffuses faster than nitrogen in flames of propane and other heavier hydrocarbons. In mixtures of air with propane or heavier hydrocarbons, the transition between stable and unstable regimes is predicted in mixtures that are leaner than the mixture corresponding to the peak of the burning velocity curve, in agreement with experimental observations. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 5, pp. 14–22, September–October, 2005.     

降冰片二烯光敏异构反应动力学

以降冰片二烯为原料,四乙基米氏酮为光敏剂,在无溶剂条件下,采用循环式反应器研究了降冰片二烯光敏异构反应动力学。结果表明,反应前期降冰片二烯的浓度下降较快,反应后期降冰片二烯的浓度下降变缓。反应速率可用一级反应动力学方程表达,反应活化能为29 173 J/mol,指前因子为1026 min-1。     

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。     

3种肠杆菌科细菌的耐药性变迁

目的研究大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌的耐药性变迁。方法对2007～2009年临床分离的大肠埃希菌(645株)、肺炎克雷伯菌(260株)和阴沟肠杆菌(150株),采用纸片扩散法进行体外药敏测定,并依据美国临床实验室标准化协会(Clinical and Laboratory Standards Institute,CLSI)规定的标准,分析3种肠杆菌科细菌的耐药性变迁。结果大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌对氨苄西林的耐药率均较高;对头孢他啶的耐药率低于头孢噻肟;与2007年比较,2008年和2009年对头孢吡肟的耐药率明显增长;未发现对亚胺培南耐药菌株的产生。结论细菌耐药性不断增强已成为临床治疗面临的重要难题,应从耐药监测、医院感染控制、合理使用抗生素等多方面努力,减少细菌耐药性的产生。     

我国聚碳酸酯工业发展概况

介绍我国聚碳酸酯生产能力和消费需求,对聚碳酸酯在信息工业中的应用作了简短介绍     

联轴器找正浅议

以实际检修过程中出现的情况入手,对联轴器可能遇到的偏移情况;找正时的测量方法;联轴器的找正步骤;联轴器找正时的计算和调整量;联轴器找正时的注意事项等五个方面进行了详细的阐述.     

谈化学教学过程中哲学观点的应用

高职阶段学生的辩证逻辑思维开始占优势，在化学教学过程中贯彻应用哲学观点既有利于学生辩证逻辑思维的开发，又能更好地掌握化学学科的思想精髓。     

Synthesis of fine powders of KTP-group compounds of stoichiometric composition

Precipitation of crystalline monophase nanopowders (50-100 nm in diameter) of stoichiometric binary orthophosphates of titanyl and alkaline metal in aqueous solutions has been studied. It has been shown that, in the formation of those powders, titanyl hydrophosphate can be used as a precursor. Rising temperature and alkaline ion concentration in the solution decrease the size of the powder grains, while elongating the exposure of the synthesized solid phase in the suspension increases grain sizes. An effective technique to synthesize fine-dispersed powders of monophase stoichiometric binary orthophosphates of titanyl and alkaline metal has been developed.     

Analysis of products of high-temperature pyrolysis of various hydrocarbons

Ethane, ethylene, acetylene, propane and neopentane have been pyrolyzed at 1173 K, and methane at 1372 K in a flow system, and the volatile pyrolysis products analyzed. Eleven aromatic hydrocarbons, containing 14 or fewer carbon atoms, accounted for 98 + % of the liquid products recovered in each case. Benzene was the main product, followed by naphthalene. No compounds with branched chains or multiple substituents were present, and compounds containing even numbers of carbons comprised 93–99% of each mixture. Acetylene was a major component of the gaseous effluent from each of the initial hydrocarbons. The effect of temperature on the composition of the gaseous effluent during pyrolysis of methane, ethane and ethylene was determined. Carbon film deposition from methane commenced at about 1273 K; from ethane at 1015 K and from ethylene at 1100 K, in each instance coinciding with the appearance of acetylene in the effluent. As the temperature was raised, at first the increase in the rate of carbon deposition closely followed the increase in the concentration of acetylene in the effluent. It is proposed that acetylene may be a common factor in the pyrolysis of aliphatic hydrocarbons, perhaps acting as the precursor of both surface carbon and aromatic hydrocarbons by a process of head-to-tail linkage of two-carbon units at active surface sites to form chains that then undergo dehydrogenation to carbon or cyclization and desorption as aromatic species.