Performance Analysis of Automated Control System for Condenser Water Treatment Unit

The air conditioning system in the Umm Al-Qura University (Albdiya Campus) was conceived to be a district cooling by a remote chilled water plant. Recently, there are two chilled water plants in the university installed strategically to provide chilled water to all the academic and administrative buildings of the university through distribution network with total capacity approximately of 12,000 tons of refrigeration. The plants were built based on cooling towers with open water cycle as heat rejection system. Water treatment chemicals has been used to protect the cooling systems from corrosion, scaling and microbiological fouling accompanied with dissolved and suspended water impurities. Different methods are being used to determine and control the treatment chemical concentrations and system performance indicators. Traditional chemical controller has drawback of indirect measurements and set points. The purpose of this paper is to present a solution to overcome the problems of traditional and conventional chemical treatment and control sys-tems. Central cooling plant number (1) assigned to perform experimental setup using new chemical treatment technology. Advanced automatic chemical treatment controller installed on condensers (1, 2 and 3), and certain key performance indicators were selected and monitored such as chemical and water consumption, power, energy saving, and maintaining system integrity and efficiency. Satisfactory results were obtained in terms of performance and cost of operation.

A Study of Water Treatment Chemical Effects on Type I” Pitting Corrosion of Copper Tubes

It is known that one of the causes of pitting corrosion of copper tubes is residual carbon on the inner surface. It was confirmed that type I” pitting corrosion of the copper tube is suppressed by keeping the residual carbon amount at 2 mg/m2 or less, which is lower than that of the type I’ pitting corrosion, or by removing the fine particles that are the corrosion product of galvanized steel pipes. The developed water treatment chemical was evaluated using three types of copper tubes with residual carbon amounts of 0 mg/m2, 0.5 mg/m2, and 6.1 mg/m2. The evaluation was conducted for three months in an open-circulation cooling water system and compared with the current water treatment chemical. Under the current water treatment chemical conditions, only the copper tube with a residual carbon amount of 6.1 mg/m2 showed a significant increase in the natural corrosion potential after two weeks, and pitting corrosion occurred. No pitting corrosion and no increase in the natural corrosion potential were observed in any of the copper tubes that were treated with the developed water treatment chemical. In addition, the polarization curve was measured using the cooling water from this field test, and the anodic polarization of two cooling waters was compared. For copper tubes with a large amount of residual carbon, the current density near 0 mV vs. Ag/AgCl electrode (SSE) increased when the developed water treatment chemical was added.

基于电磁场技术的TriIns Water系统在水处理中的应用研究

循环冷却水处理是诸多工业生产和中央空调系统运维的关键一环,良好的阻垢、缓蚀、微生物控制可以延长设备的使用寿命并降低其能耗。文章介绍的TriIns Water智水系统是一种专门为循环冷却水处理系统设计的全方位纯物理解决方案,绿色、智能、环保、节能,能够有效控制循环冷却水处理中的三大问题,完全无化学药剂添加。该系统在循环冷却水处理系统中进行了应用,取得了良好的效果,零排污废水的特性完全符合当前的环保形势,是一项对环境友好的绿色节能技术,可推广应用于分布式能源站、发电厂、钢铁厂及石化厂等循环冷却水系统。

环保型水处理药剂在工业循环水中的应用

某化工企业的循环水水质比较复杂,换热管中结垢较严重且已经出现腐蚀现象,严重影响了企业的正常生产。针对这一问题,采用不含磷、氮的原料马来酸(MA)和烯丙基磺酸钠(SAS)合成一种绿色环保型药剂MA/SAS。将其与药剂进行复配,采用静态阻垢实验及旋转挂片实验在企业循环水中测定复配药剂的阻垢性能和缓蚀性能。实验结果表明,该复配药剂应用于该化工企业的循环水系统后,有效抑制了结垢和腐蚀现象的发生,可以满足技术指标要求,为企业带来了一定的经济效益。

探究火电厂水耗降低方案及实施方法

火电厂水耗量过大时,将会影响厂内效益,不利于促进可持续发展。基于此,本文主要针对火电厂水耗降低方案及实施方法进行探讨,首先分析了水耗来源,基于水耗降低意义探究实际方案与实施方法,重点阐述了锅炉、冷却系统、废水处理技术改进方法,最后结合实际案例剖析水耗降低实施内容,以增强技术参考性。研究发现,火电厂水耗降低有利于降低成本费用,推动全厂实现绿色发展,类似工厂应持续加强水耗控制,实现生态生产。

Improvement to anti-rust property of hot rolled rebar by compact oxide scale

A method was proposed to improve the anti-rust property of hot rolled rebar, which uses oil–water emulsion cooling instead of water cooling after hot rolling. The experiments were carried out by two cooling methods, one cooled by water, the other cooled by oil–water emulsion. The results of wet/dry cyclic accelerated corrosion test showed that the anti-rust property of rebar cooled by oil–water emulsion was better than that by water obviously. The results of OM, SEM and EPMA analysis indicated that these two scales contained three layers: an outer Fe_3O_4 layer, an intermediate Fe O layer with island-shaped pro-eutectoid Fe_3O_4, an inner eutectoid Fe_3O_4 layer. For the water cooled rebar, all three layers of oxide scale were relatively thin. Moreover, the scale had plenty of defects such as porosity, and crack. However, for the oil–water emulsion cooled rebar, all three layers of oxide scale were relatively thick and compact, which played an important role in protecting the rebar from atmospheric rust.

Scaling and clogging treatment of aging tunnel drainage pipes in karst areas using eco-friendly acid agent

In karst areas,the drainage pipes of aging tunnels are prone to be clogged by precipitated carbonates,resulting in lining cracking and tunnel leaking.As a result,not only the driving safety will be deteriorated,but also the water pressure on the lining might also be elevated significantly.For the structural stability and service lifespan of old tunnels,it is of great importance to remove these precipitated carbonates in time.Traditional treatment methods are often destructive to some extent or not efficient enough.This study aims to experimentally develop an eco-friendly acid-based chemical cleaning method to remove carbonate precipitations efficiently.The proposed chemical cleaning agent is an aqueous solution with strong acidity,consisting of sulfamic acid,water,and additives.The factors affecting the cleaning efficiency include the acid solubility,temperature and flow rate of the cleaning agent,as well as additives.Elevating the solution temperature to 50
C or a flow rate of no less than 0.2 m/s can improve cleaning efficiency.Although the salt effect cannot work,1 wt%of polymaleic acid as a surfactant could further promote the cleaning rate.The cleaning efficiency will increase with the flow rate in a power function.The relatively low flow rate that improves the cleaning rate considerably can avoid highpressure-induced mechanical damage to tunnel drainpipes.The waste could be easily treated to acceptable levels using commercial sewage treatment products and can also be recycled in agriculture.With the chemical cleaning,the water pressure at the arch springing of the lining will reduce with the increased radius of transverse drainpipes in a power function.The proposed acid-based cleaning method,which is highly efficient,non-or low-destructive to aging tunnels,sufficiently safe for humans,and friendly enough to the environment,will offer a promising alternative to remove the precipitated carbonates in tunnel drainpipes efficiently.

Seed germination of Albizia procera(Roxb.)Benth.in Bangladesh:a basis for seed source variation and pre-sowing treatment effect

An experiment in seed morphology and seed germination techniques of Albizia procera was carried out in the nursery of the Forestry and Wood Technology Discipline, Khulna University, Bangladesh in order to discover the source variation in seeds and pre-sowing treatment effects on seed germination. Mature seeds ofA. procera were collected from healthy trees in home garden plan- tations from five different districts in Bangladesh and treated with four pre-sowing treatments, i.e., control, immersion in cold water （4~C for 24 h） and immersion in hot water （80~C for 10 min and 100~C for 1 min）. The average length, width and thickness of seeds were calculated as 0.502 ＋ 0.485, 0.420 ~ 0.060 and 0.191 ~ 0.118 cm, respectively. Germination was conducted in poly-bags with a mixture of topsoil and cow dung in a ratio of 3：1. The results revealed that pre-sowing treatments affected the rate of germination of seeds, which significantly increased the germination percentages of seeds in hot water treatments compared with those in control （60.60%） and the cold water treatment （4℃ for 24 h, 63.53%）. The highest germination success was 82.07% in the treatment of im- mersion in hot water （80℃） for 10 min, followed by 79.00% in immersion in hot water （100℃） for l rain. Germination started 4 to 6 days after seed sowing and completed in a period of 22 to 25 days in all treatments. ANOVAs showed statistically significant dif- ferences （p 〈 0.05） in seed germination starting dates, closing dates, germination percentages and rates of germination among treat- ments, but no significant differences in seed germination starting dates, closing dates, germination period, germination percentages and rates of germination among the seed sources. The study also revealed that the interaction between seed source variation and treat- ment effect significantly differed in seed germination starting dates, closing dates, germination percentages and rates of germination. The hot water （100℃ for 1min） treatment is recommended for seed germination ofA. procera in rural Bangladesh.

Bench and Full Scale Study of Removal Effect and Mutagenicity on Mesocyclops Leukarti with Chlorine Dioxide

Mesocyclops Leukarti of zooplankton propagates excessively in eutrophic water body and it can not be effectively inactivated by the conventional process in drinking waterworks for its special surface structure. In this paper, a study of removal efficiency on Mesocyclops Leukarti with chlorine dioxide in a drinking waterworks was performed. Bench scale results showed that chlorine dioxide is more effective against Mesocyclops Leukarti. And Mesocyclops Leukarti could be effectively removed from water by 1.0 mg/L chlorine dioxide preoxidation cooperated with the conventional process during the full scale study. The chlorite, by.product of prechiorine dioxide, was constant at 0.45 mg/L after filtration, which was lower than the critical value of the USEPA. GC-MS examination and Ames test showed that the quantity of organics and the mutngenicity in the water treated by chlorine dioxide is obviously less than that of prechlorination.

电化学水处理技术降低循环水硬度的实验研究

使用电化学法处理某焦化企业实际循环水的实验,探究了循环水的硬度和碱度去除率随处理时间的变化情况。分析了电流密度、水力停留时间、极板间距等实验操作参数以及商用阻垢剂对电解效果和能耗的影响。结果表明:硬度和碱度去除率随处理时间呈现先上升后平稳的趋势,且碱度去除率总是高于硬度去除率;电流密度为70 A/m^(2)、水力停留时间为6 min、极板间距为3 cm时电解效果最佳,硬度和碱度去除率可达27%以上,单位能耗低至13 kWh/kg;商用阻垢剂对电解效果具有阻碍作用。

槐米提取物/PBTCA复配物阻硫酸钙垢性能研究

采用静态阻垢法研究了槐米提取物和其与市售2-膦酸基丁烷-1,2,4-三羧酸(PBTCA)二元复配物对循环冷却水阻硫酸钙垢性能。结果表明,单一的槐米提取物阻硫酸钙垢效果随槐米提取物浓度的增加呈先增加后递减的趋势,最佳的浓度为21 mg/L,阻垢率可达20.45%;槐米提取物与PBTCA的二元复配物呈现较好的阻硫酸钙垢性能,在质量配比PBTCA∶槐米提取物=1∶2,投加量为21 mg/L,保温时间4 h, CaCl_(2)浓度5.55 mg/mL,保温温度70℃时,阻硫酸钙垢率达到93.75%,硫酸钙垢未见明显的规整结构而呈团块状;热重分析表明,槐米提取物在250℃时可发生分解,表现良好的热降解性能。

某大科学装置项目工艺冷却水系统设计

介绍了某在建大科学装置项目的工艺冷却水系统设计,包括服务对象、系统形式、系统组成、水温控制策略、流量控制策略等方面的内容。简述了热回收型水源热泵在工艺冷却水系统中的应用方案,并对工艺冷却水系统设计后续可开展的工作和研究提出了3个方向。

石化废水处理厂特征污染物变化及水质安全研究

石化废水污染控制与水质安全是水环境领域污染防治的重要课题,但是目前关于石化废水处理工艺中特征污染物的组成变化及水质安全性尚未深入探讨。研究了某石化废水处理厂在废水处理过程中废水特征污染物的浓度变化和毒性削减效应。结果表明,预处理阶段COD和石油类去除率分别为36.38%和95.16%,出水生物毒性有效降低。生化处理单元COD和氨氮去除率分别达到63.19%和43.21%,废水中酚类、酯类、胺类等有机物含量显著降低。石化废水经过深度处理后,COD、BOD5、石油类、氨氮、总氮分别为(32.54±4.93)、(2.19±1.09)、(0.04±0.01)、(2.32±0.31)、(27.08±1.45)mg/L。由于酚类和含氮杂环有机物得到有效去除,最终出水毒性单位(TU)值为0.32,无急性生物毒性。该石化废水处理厂所采用的废水处理工艺能够有效去除废水中多种特征污染物,出水无显著急性生物毒性,对水环境生态安全影响较小。

盾构井底板混凝土温控参数敏感性分析

以珠江三角洲水资源配置工程的典型盾构井底板为例,采用saptis三维有限元软件,进行浇筑温度和通水冷却温控参数敏感性分析。结果表明,高温季节降低浇筑温度有利于控制混凝土内部最高温度,浇筑温度每增高1℃,内部最高温度增加约0.79℃,建议将浇筑温度降低至23℃;优化通水冷却参数(加密冷却水管,降低通水水温,适当延长通水时长)能达到良好的温控防裂效果。

南水北调渠道混凝土裂缝的预防与处理试验

南水北调中线工程的输水渠道以薄壁混凝土为主,其受地形、地质条件、气候及施工工艺等因素影响极易出现裂缝。混凝土浇筑前,参建单位进行了多次工艺试验,总结出一系列有效的防范与治理措施并广泛应用于渠道混凝土工程,成功保证了工程实体和外观质量,为类似工程的施工积累了宝贵的经验,具有一定的借鉴意义。

膜阻垢剂及其阻垢机理研究新进展

由于水资源紧缺的问题,反渗透膜处理技术发展迅速。膜阻垢剂因能减缓膜组件的结垢、提高水净化效率,因而被广泛应用于反渗透膜处理技术。常见的膜阻垢剂有磷酸盐类、阴离子聚合物类、阳离子聚合物类以及绿色阻垢剂等,一般认为它们可以通过螯合、分散、晶格畸变等作用或阈值效应阻碍或缓解垢的形成。树枝状聚合物膜阻垢剂具有优异的阻垢性能,与其结构相似的球形聚电解质刷作为一种刷状聚合物膜阻垢剂也在膜处理领域中崭露头角。深入研究新型膜阻垢剂的阻垢机理可为设计开发针对性强、经济环保的高效阻垢产品奠定理论基础。

电磁场与电化学对循环冷却水系统中设备腐蚀及结垢的影响

循环冷却水对工业生产至关重要,但若长期使用,会使传输管道及换热设备产生腐蚀和结垢,这一直是循环冷却水使用过程中存在的顽疾。将环保、高效、时兴的新技术电磁场(旋磁加能器)和电化学(吸垢仪)创新地联合运用到水质更差的中水中,探索这种联合技术在循环冷却水系统上的防腐、防垢效果。通过搭建的小型工业水循环系统平台,验证了这种联合技术可有效减少循环冷却水系统的腐蚀和结垢问题,改善循环冷却水系统的运行状态,另外,为工业循环水企业提供了将中水用作循环冷却水的新思路,可为企业增加经济效益,实现节能减排。

毛薯提取物的制备及阻垢缓蚀性能研究

通过浸提法对毛薯水提物(HPE)进行制备,并对毛薯提取物的阻碳酸钙垢、硫酸钙垢以及缓蚀性能进行了评价。结果发现,随着毛薯提取物浓度增加,其阻碳酸钙、硫酸钙垢率以及缓蚀率均有所提高。当毛薯提取物浓度为1500 mg/L时,阻碳酸钙垢效率达到61.0%;当提取物浓度达到200 mg/L时,阻硫酸钙垢效率接近100%;当毛薯提取物浓度为500 mg/L时,其在0.1 mol/L硫酸溶液中的缓蚀率可达80%左右。在探究加热时间、温度、Ca^(2+)浓度变量与阻垢率之间的关系时,发现随着变量条件的提高,阻碳酸钙、硫酸钙垢率均出现了不同程度的下降。结果表明,毛薯提取物具有较好的阻垢、缓蚀性能。

电化学法处理循环冷却水的研究进展

循环冷却水系统已广泛应用于工业生产的冷却过程,其显著提高水资源的利用效率。然而,结垢问题直接影响循环冷却系统的稳定性。电化学法可以有效缓解结垢带来的负面问题。因此,本文从两个方面(调控阴极面积,高效分离氢离子和氢氧根)详细阐述电化学法处理循环冷却水的最新研究进展,以更好地利用电化学法处理循环冷却水。

低温季节泵送混凝土结构施工期温控防裂研究

低温季节施工时针对泵闸等结构泵送混凝土防冻与防裂的技术难题,以SYG工程为例,结合工程实际施工过程及现场温控监测成果进行大体积泵送混凝土温控防裂反馈分析;对比分析了不通水工况与实际通水工况下的应力曲线与混凝土容许拉应力曲线,并结合现场温控过程中存在的主要问题探讨了低温季节下泵闸工程的温控防裂技术.结果表明,在-8℃的较低温度下,采取充分的水管冷却和严格的表面保温措施可有效控制结构内部最高温度、内外温差以及最大拉应力水平,减小水闸结构开裂风险.本工程温控实践经验可为类似条件下的泵闸工程提供参考.