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%.

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%).

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.

Transient Heat Transfer Study of Direct Contact Condensation of Steam in Spray Cooling Water

We conducted a transient experimental investigation of steam–water direct contact condensation in the absence of noncondensible gas in a laboratory-scale column with the inner diameter of 325 mm and the height of 1045 mm. We applied a new analysis method for the steam state equation to analyze the molar quantity change in steam over the course of the experiment and determined the transient steam variation. We also investigated the influence of flow rates and temperatures ofcooling water on the efficiency ofsteam condensation. Our experimental results show that appropriate increasing of the cooling water flow rate can significantly accelerate the steam condensation. We achieved a rapid increase in the total volumetric heat transfer coefficient by increasing the flow rate of cooling water, which indicated a higher thermal convection between the steam and the cooling water with higher flow rates. We found that the temperature ofcooling water did not play an important role on steam condensation. This method was confirmed to be effective for rapid recovering ofsteam.

Optimized Operation of a Solar-Driven Thermoelectric Dehumidification System for Fresh Water Production

The work presents a parametric analysis of the performance of a solar-driven thermoelectric system to dehumidify air and produce fresh water. The system is combined with a solar distiller humidifying ambient air to enhance distillate output to meet the specified fresh water needs for a residential application. The presented system is a totally renewable energy-based system taking advantage of the clean solar energy. A model is developed to simulate the air dehumidification process using TEC （thermoelectrically cooled） channels. An optimization problem for setting system operational parameters is formulated to meet the fresh water requirement of 10 liters per day for a typical residential application in the Lebanese coastal humid climate. Using five TEC channels of length of 1.2 m and area of 0.07 - 0.05 m^2 integrated with 1.2 m^2 solar distiller is capable of meeting the water demand, where the air mass flow rate introduced to each TEC channel is optimally set at 0.0155 kg/s. The optimal electrical current input to the TEC modules from the photovoltaic solar panels varied depending on the month and is set at 2.2 A in June, 2.1 A in July and 2.0 A in August, September and October per each TEC module.

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。

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.

Effect of Cooling Water Flow Path on the Flow and Heat Transfer in a 660 MW Power Plant Condenser

The effect of the cooling water flow path on the flow and heat transfer in a double tube-pass condenser for a 660 MW power plant unit was numerically investigated based on a porous medium model. The results were used to analyze the streamline, velocity, air mass fraction and heat transfer coefficient distributions. The simulations indicate that the cooling water flow path is important in large condensers. For the original tube arrangement, the heat transfer with the lower-upper cooling water flow path is better than that with the upper-lower cooling water flow path. The reason is that the steam cannot flow into the internal of upper tube bundle and the air fractions are higher in the upper tube bundle with the upper-lower cooling water flow path. An improvement tube arrangement was developed for the upper-lower cooling water flow path which reduced the back pressure by 0.47 kPa compared to the original scheme. Thus, the results show that the tube arrangements should differ for different cooling water flow paths and the condenser heat transfer can be improved for the upper-lower cooling water flow path by modifying the tube arrangement.

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.

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。

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。

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。

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。

QDQ2-1型水电解制氢设备冷却循环水控制改进方法研究

为了保障制氢设备的良好运行,文章进行水电解制氢设备冷却循环水控制改进方法的研究,利用温度控制电路将电解槽温度控制在预设范围,使水电解制氢设备始终工作在最佳温度。通过10个月的试用检验,设备未出现超温停机现象,改造效果理想。研究方法具有在同型号制氢设备中推广的可行性。

水能风机在循环水冷却系统的应用

介绍了循环水冷却系统中采用水能风机代替大功率电动机实现节能降耗的实施措施,分析了改造后带来的经济效益。

循环冷却水系统的电化学水质稳定技术案例分析

水垢沉积和金属腐蚀会导致循环冷却水系统传热效率下降和能耗增加,严重影响工业生产的安全稳定运行。以某厂循环水系统的电化学除垢设备为案例,通过分析其处理效果和经济效益,为电化学技术处理循环冷却水的应用推广提供依据。现场所得运行数据表明,该厂所采用的电化学除垢设备能够有效改善水质,防止结垢,控制循环冷却水系统的腐蚀情况。每年减少循环水系统补水量和排污量各4.38×10^(5) t,并显著降低药剂投加量。经济核算显示该电化学系统每年可节省约212.9万元。

自然通风湿式冷却塔节水方案的数值研究

为降低自然通风湿式冷却塔的耗水量,本文采用一种可用于回收其蒸发损失的空气冷凝器结构,并通过数值模拟方法对其节水特性展开研究。首先基于空气运动控制方程和水蒸气冷凝模型,建立了用于分析空气冷凝器节水特性的数学模型,其次分析了冷却空气流速、空气冷凝器的结构尺寸和材质等因素对该冷凝器节水特性的影响。研究结果表明:空气冷凝器的单位面积节水量随着冷却空气流速以及冷凝器宽度的增大而增大,但随着冷凝器长度和高度的增大而减小;空气冷凝器的材质和壁厚对其单位面积节水量没有显著影响,空气冷凝器可采用重量轻和成本低的薄壁PVC来加工制造。

基于热泵技术的余热回收供热系统

传统热电厂的循环冷却水中含有大量的低品位余热,利用热泵技术对其进行回收,能够显著提升供热系统的能源利用效率,有利于实现节能减排和“碳中和”目标。设计基于单、双吸收式热泵机组的余热回收供热系统,旨在有效利用循环冷却水中的余热,增加供热能力并分析系统性能。结果表明,与传统供热系统相比,两种余热回收供热系统均可显著回收循环冷却水的热量,提高系统供热量并大幅减少能源消耗,带来可观的经济收益;双吸收式热泵机组系统展现出更优异的热力性能,具备显著的节能减排优势。分析循环冷却水入口温度和一次网回水温度对双吸收式热泵机组性能的影响,发现循环冷却水温度对系统性能影响较大,随着循环冷却水温度的升高,系统的供热量增加比例、节约标煤量和新增供热面积均增加,而一次网回水温度对系统性能的影响较小,随一次网回水温度的升高,系统的供热量增加比例、节约标准煤量和新增供热面积几乎不变。