Optimization of circulating cooling water systems based on chance constrained programming

Recent research on deterministic methods for circulating cooling water systems optimization has been well developed. However, the actual operating conditions of the system are mostly variable, so the system obtained under deterministic conditions may not be stable and economical. This paper studies the optimization of circulating cooling water systems under uncertain circumstance. To improve the reliability of the system and reduce the water and energy consumption, the influence of different uncertain parameters is taken into consideration. The chance constrained programming method is used to build a model under uncertain conditions, where the confidence level indicates the degree of constraint violation. Probability distribution functions are used to describe the form of uncertain parameters. The objective is to minimize the total cost and obtain the optimal cooling network configuration simultaneously.An algorithm based on Monte Carlo method is proposed, and GAMS software is used to solve the mixed integer nonlinear programming model. A case is optimized to verify the validity of the model. Compared with the deterministic optimization method, the results show that when considering the different types of uncertain parameters, a system with better economy and reliability can be obtained(total cost can be reduced at least 2%).

Corrosion Inhibition by Co-Immobilized Lysozyme and Lipase in Circulating Cooling Water System

The corrosion inhibition performance of co-immobilized lysozyme and lipase was investigated in a recirculating cooling water system. Four methods were carried out in co-immobilization, and the operating parameters were optimized by using the respond surface methodology(RSM). The corrosion inhibition performance of co-immobilized lipase and lysozyme was evaluated by weight loss measurements and electrochemical measurements. The results revealed that the optimal co-immobilization method should be the sequential immobilization of lysozyme and then lipase. The inhibition efficiency was 86.10% under the optimal co-immobilized conditions. Electrochemical data showed that co-immobilized lysozyme and lipase was a mixed-type inhibitor and the corrosion inhibition efficiency was 81%.

MIC in Circulating Cooling Water System

MIC is one of the main problems of circulating cooling water system. The direct economic loss by MIC is about 300 to 500 billion dollars. It is good to understand MIC in order to control MIC. Source and species of microorganisms was introduced firstly. There are three kinds of microorganisms in the system, including bacteria, fungi and algae. Species of these microorganisms are shown in the paper. Then, mechanisms of MIC are analysed. Although there is no universal mechanism of MIC, MIC is still mainly an electrochemical corrosion in nature. Meanwhile, the mechanisms on SRB and iron bacteria are introduced in details. At last, several methods of microorganisms control are put forward in the paper.

Ion Exchange Softening and Alkalization Treatment for Zerodischarge of Circulating Cooling Water

In order to solve the problems including pipe corrosion, scaling and microbial growth, which severely threat safe op-eration of circulating cooling water system, this paper proposes ion exchange softening and alkalization process to solve these problems and carries out a series of studies to study the feasibility of ion exchange softening and alkaliza-tion process in the simulation process of circulating cooling water system. The studies include product water quality of ion exchange softening and alkalization process, effect on the performance of carbon steel and brass, and the inhibition that suppresses microbial growth. The results indicate that ion exchange softening and alkalization process is feasible to prevent the circulating cooling water system from scaling, pipe corrosion, and microbial growth without any other chemicals. Thus circulating cooling water system can achieve zerodischarge of wastewater.

Laccase Immobilized on Mesoporous Silica Materials and Its Corrosion Inhibition Performance in Circulating Cooling Water System

Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter is 2.55 nm, while the specific surface area is 1 088.9 m2/g. Mesoporous SiO_2 microspheres adsorb glutaraldehyde and immobilize laccase by means of the aldehyde group in glutaral which can react with the amidogen of laccase. The immobilization conditions were optimized at a glutaraldehyde concentration of 0.75%, a crosslinking time of 8 h, a laccase concentration of 0.04 L/L and an immobilization time of 10 h. When diesel leakage concentration was 80 mg/L, the highest corrosion inhibition efficiency of immobilized laccase reached 49.23%, which was slightly lower than the corrosion inhibition efficiency of free laccase(59%). The diesel degradation ratio could reach up to 45%. It has been proved that the immobilized laccase could degrade diesel to inhibit corrosion.

The Preliminary Research of Sea Water District Heating and Cooling for Tallinn Coastal Area

This paper describes possibilities to utilize sea water for district heating and cooling purposes in Tallinn costal area. The sea water temperature profiles and suitability of heating and cooling generation are studied for continental climatic conditions. The district network study bases on 21 buildings located near to the Gulf of Finland. Industrial reversible heat pump technology is selected to cover heating and cooling loads for the new buildings. Combination of existing district heating and heat pump technology is considered for existing buildings. The results show possibilities, threats and need for further research of the sea water based heat pump district network implementation.

Removal of kathon by UV-C activated hydrogen peroxide:Kinetics,mechanisms,and enhanced biodegradability assessment

Kathon(CMI-MI),a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one(CMI)and 2-methyl-4-isothiazolin-3-one(MI),was extensively used in industry as a nonoxidizing biocide or disinfectant.However,it would show adverse effects on aquatic life when it is discharged into surface water.In this study,the removal performance,parameter influence,degradation products and enhancement of subsequent biodegradation of CMI-MI in UV/H_(2)O_(2)system were systematically investigated.The degradation rate of CMI-MI could reach 90%under UV irradiation for 20 min when the dosage of H_(2)O_(2)was 0.3 mmol·L^(–1).The DOC(dissolved organic carbon)mineralization rate of CMI-MI could reach 35%under certain conditions([H_(2)O_(2)]=0.3 mmol·L^(–1),UV irradiation for 40 min).kobs was inversely proportional to the concentration of CMI-MI and proportional to the concentration of H_(2)O_(2).The degradation rate of CMIMI was almost unchanged in the pH range from 4 to 10.Except the presence of CO_(3)^(2-)inhibited the removal rate of CMI-MI,SO_(4)^(2-),Cl^(-),NO_(3)^(-),and NH_(4)^(+) did not interfere with the degradation of CMI-MI in the system.It was found that UV/H_(2)O_(2)system had lower energy consumption and more economic advantage compared with UV/PS system by comparing the EEO(electric energy per order)values under the same conditions.Two main organic products were identified,namely HCOOH and CH_(3)NH_(2).There’s also the formation of Cl^(-)and SO_(4)^(2-).After UV and UV/H_(2)O_(2)photolysis,the biochemical properties of CMI-MI solution were obviously improved,especially the UV/H_(2)O_(2)treatment effect was better,indicating that UV/H_(2)O_(2)technology is expected to combine with biotechnology to remove CMI-MI effectively and environmentally friendly from wastewater.

地铁车站围护结构耦合埋管换热系统运行策略研究

以某地铁车站为研究对象,模拟了其全年动态负荷,确定了地源热泵参数,建立了估算热泵出力及耗电量的参数模型,结合建立的动态换热模型得到了地源热泵系统-埋管阻容耦合仿真模型。以10年为运行周期,计算了埋管出水温度和换热量,分析了不同工况下的换热性能,提出了热泵机组联合冷却塔辅助换热的运行策略。结果显示:围护结构耦合埋管换热系统在长期运行工况下存在机组停机或机组出力不足的情况,当负荷为计算负荷的80%时,可以保证热泵机组出力满足需求;冷却塔联合运行策略在制冷季可以有效降低埋管出水温度,在过渡季冷却塔的免费冷量可以降低埋管出水温度1~2℃,在长期运行工况下具有较好的地温恢复效果。

Model free optimization of building cooling water systems with refined action space

Deep Q Network(DQN)is an efficient model-free optimization method,and has the potential to be used in building cooling water systems.However,due to the high dimension of actions,this method requires a complex neural network.Therefore,both the required number of training samples and the length of convergence period are barriers for real application.Furthermore,penalty function based exploration may lead to unsafe actions,causing the application of this optimization method even more difficult.To solve these problems,an approach to limit the action space within a safe area is proposed in this paper.First of all,the action space for cooling towers and pumps are separated into two sub-regions.Secondly,for each type of equipment,the action space is further divided into safe and unsafe regions.As a result,the convergence speed is significantly improved.Compared with the traditional DQN method in a simulation environment validated by real data,the proposed method is able to save the convergence time by 1 episode(one cooling season).The results in this paper suggest that,the proposed DQN method can achieve a much quicker learning speed without any undesired consequences,and therefore is more suitable to be used in projects without pre-learning stage.

上海市某商业广场项目高效制冷系统改造工程实践

以上海市某商业广场项目高效制冷系统改造工程为例,介绍了该工程概况及高效制冷系统改造工程的全过程服务,从空调制冷系统现场勘测及检测评估、集成磁悬浮副冷站高效机房设计、主冷站高效制冷系统设计、高效制冷系统实施重难点解决方案、高效制冷系统的改造实效5个方面进行了详细说明。提出了既有大型商业高效制冷系统运行痛点和解决措施,系统性地归纳、总结了适用于改造工程的高效制冷系统的技术路径与实施建议。

制酒厂区工艺双循环水冷冷却系统热回收应用研究

酱香型白酒生产过程需要冷却才能使酒蒸汽凝结成酒并降温至工艺要求的出酒温度,常用的冷却介质有空气和水,冷却过程中酒蒸汽会向冷却介质释放大量热量。采用风冷方式时其热量释放于空气中,热回收利用难度较大。常规情况采用水冷方式时冷却水出水温度约为60~70℃,可用于加热生活热水和锅炉水,但其他可利用的热回收途径较少。为了提高白酒生产中的冷却水余热利用率,提出了工艺双循环水冷冷却系统,其高温冷却水出水温度可达90℃左右,高温冷却水中的热量约占90%,可用于驱动增温型热泵制取蒸汽,也可用于加热锅炉水和生活热水。采用该双循环水冷冷却系统可进一步提高白酒生产中的余热回收利用率,达到节能低碳的效果。

60 MW循环流化床锅炉水冷壁泄漏原因分析

旨在分析某热电厂2号循环流化床锅炉水冷壁管泄漏的原因。通过宏观检查、金相检查及拉伸试验等方法,对泄漏管样及对比管样的焊接质量、组织状态及力学性能进行了全面检测。宏观检查发现,泄漏管样及一处对比管样堆焊处存在焊接裂纹及局部焊瘤,表明焊接时电流过大导致母材过热熔化;金相检查进一步证实了过烧组织的形成及焊接裂纹的扩展路径;拉伸试验结果表明,未泄漏管样的力学性能符合标准要求。泄漏原因为水冷壁管表面堆焊时焊接电流过大,导致母材过烧并产生焊接裂纹。

沿海电厂项目用HDPE缠绕结构壁管及配套件的设计开发

本文给出设计开发沿海电厂循环冷却水用HDPE缠绕结构壁管及配套件新产品要满足的工况,材料性能及结构及相关测算等,并通过产品发展及实际案例剖析未来的发展形势,在应用中具有显著的优势,通过工程应用提升我国在该新材料领域的产品研发、设计、制造和基建施工等方面的国际领先地位。

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。

PARAMETERS OF WATER CIRCULATION NETWORK FOR A DISTRICT HEATING AND COOLING SYSTEM

In a district heating and cooling system, i.e. Beijing combined heating cooling and power (CHCP) system studied here, the high temperature water generated by two cogeneration plants circulates through a network between the plants and heat substations. At heat substations, the supply water of high temperature from the network drives absorption chillers for air-conditioning in summer and meets space heating demands in winter or domestic hot water demands by heat exchangers in the whole year. The parameters, i.e. supply/return water temperatures in the network, have a great impact on primary energy consumption (PEC) of the absorption chillers, circulation pumps and domestic hot water (DHW), which is studied in this paper.

基于PROFIBUS&PROFINET楼宇循环供水系统的设计

基于PROFIBUS&PROFINET楼宇循环供水系统的设计,提出二次用水观点,描绘循环水系统的基础设施结构和基本组态元素,主要研究、探讨用于楼宇实现二次用水的硬件解决方案以及理想环境。

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。

电化学循环水阻垢技术在电力行业的应用展望

在工业发展中,循环冷却水的结垢问题一直备受关注,有效的阻垢技术对降低生产能耗和减少水资源的浪费具有重要意义。电化学阻垢技术因具有高效、无需投加药剂、同步杀菌等优点受到了广泛的关注。从电化学阻垢技术的发展、原理以及实际应用等方面,综述了电化学阻垢技术在循环冷却水处理中的应用情况并展望了在电力行业冷却水处理中的应用前景。包括以时间为向导结合文献计量学可视化分析,比较了近十年阻垢技术相关研究热点;进一步从电化学阻垢技术的简介、与传统阻垢技术的比较、研究现状以及影响因素出发,并结合实际应用情况,提出了电化学阻垢技术尚且存在的困难和挑战,最后对电化学阻垢技术在电力行业中的应用前景进行了展望。

石墨炉原子吸收测定间接空冷机组循环水中的痕量铝

采用石墨炉原子吸收测定SCAL型间接空冷机组循环水中的痕量铝,从石墨炉工作参数、基体改进剂、试剂空白、水样前处理等方面进行了实验条件优选。实验结果表明:石墨炉灰化温度、原子化温度分别为700℃和2 700℃,不加基体改进剂条件下,铝离子标液质量浓度在0~20μg/L范围内标准曲线线性相关系数可达到0.999 8,相对标准偏差小于10%,检测下限为0.5μg/L。采用水样酸化静置1 h后直接测定并与标准加热消解法测定值进行了对比,相对误差小于5.0%,空白值小于0.5μg/L,有效解决了加热消解法空白值高的问题,提高了间接空冷机组循环水中小于10μg/L痕量铝测定的准确性。

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。