Closed Water Circuit Research Articles

Metallurgical Failure Analysis of Closed Water Circuit Containing Molybdate-Based Inhibitor

In this work, two industrial heating/cooling circuits are compared. One of the two systems failed in a short time showing severe corrosion damage and a through thickness crack close to one of the welds. The main difference between the circuits is the presence of a sodium molybdate-based corrosion inhibitor in the damaged one. The addition of these substances is very frequent in such applications, and they generally work very well in preventing serious corrosion attacks. Nevertheless, the technical literature reports other cases in which systems working with fluids containing such inhibitors failed prematurely. The authors performed a failure analysis of the damaged circuit focusing their attention on the regions where fluid leaks were observed because of through thickness cracks. This damage was located close to the pipe–flange weld. These zones were investigated by visual examination, radiographic and scanning electron microscope (SEM) analyses, metallographic observations by light optical microscope (LOM), Vickers micro-hardness tests and optical emission spectroscopy (OES) chemical analysis. The failure was related to the presence of severe pitting and crevice corrosion in the welded areas with the final activation of a further critical corrosion mechanism, i.e., stress corrosion cracking (SCC). In order to explain the shorter working life of the failed system, a physical model of the corrosion mechanisms acting on the two circuits was proposed.

An analytical study to reduce the effect of dust on the performance of solar panels using water system

The aim of this work is to study the effect of dust on the performance and efficiency of solar cells . Two solar panels were used clean and dusty each consists of 12 solar cells. The remaining challenge is to find accost-effective way to apply these principles to construct a low-cost solar cell with high and stable efficiency.
 Photovoltaic (PV) cells have social and commercial value only when they are used in a system to provide a service. This research has given a brief overview of the technical and economic considerations that allow the cells to provide such a service. An automatic closed water circuit was designed and implemented to clean and increase the efficiency of the solar panel.

Removal of volatile organic compounds from Waste air stream of a furniture factory

In this paper, an alternative to the thermal oxidation of VOC in a gaseous effluent was studied, to lessen power consumption and mitigate the environmental impact of a furniture factory located in the north of Portugal.A gas–liquid absorption of n-butyl acetate in a packed-bed column of LECA was studied to achieve a VOC outlet in agreement with the Portuguese law for effluent discharge in the atmosphere. Studies of VOC physical absorption with water were evaluated.Experiments with a continuous flow of tap water demonstrated to be very effective in removing n-butyl acetate of the air stream. Efficiencies over 90% were achieved by this method and in three experiments outlet VOC concentration remained under the imposed limit of 50 mgC/Nm3. Other experiments were registered to be above the imposed limit, even so, they were also highly effective, suggesting that if the outlet water can be reused and employed for other purposes, this solution might have an industrial interest. In the other studied approach, with a closed water circuit, the system proved to be less effective, with the removal efficiency of the VOC dropping very fast, which revealed the need for continuous treatment of the recirculated water.When introducing the microorganisms to the system, the efficiency was lower than for open circuit, averaging, 40.2%, 27.0%, 25.5%, respectively in the three experiments realized, suggesting that the system might be an interesting and a sustainable alternative to the ROT system employed at the factory, with a significant reduction in the energy consumption.

Experimental Study on the Influences of Air Flow in an Integral Hydrocarbon Display Cabinet to its Temperature and Energy Performances

This paper presents results on temperature energy performance tests of an integral refrigerated hydrocarbon (HC) display cabinet for retail food applications. Heat from the condensing unit of the cabinet is rejected to both ambient air and water/glycol mixture flowing in a closed water circuit. Air flow in the cabinet loaded with M-packages as test products was studied in order to analyze effects of air flow rate in the cabinet to its temperature and energy performances. The product and air temperatures as well as energy consumption of the cabinet were measured. The tests were conducted in a test chamber at climate class 3. It was found that the HC display cabinet with integral condensing unit was found to provide excellent energy performance with an Energy Efficiency Index below the requirement to qualify for enhanced capital allowances. The refrigeration system of the cabinet could also achieve a COP of 3.15. The study also found that higher air flow rate in the cabinet could make the product temperatures a little bit better, but the energy consumption increased approximately 7% when air flow rate was increased from 1200 m3 h−1 to 1800 m3 h−1. Air flow distribution in the cabinet was necessary to be optimized in order to comply with M0 classification cabinet.

Water-flow Gazing Curtain-wall and Ground Source Heat Pump as an Energy Saving Strategy in Buildings

Background: The thermal challenge raised by the use of traditional air-chamber glazing in contemporary architecture is not coherent with the current goals for buildings in terms of energy efficiency Methods: This paper explores the possibilities of the active water-flow glazing technology in the form of a curtain-wall, and its integration with a geothermal heat exchanger. A simulation is carried out in order to evaluate such installation, and the results of this simulation are then compared to real data collected from a built and functioning example in Spain. Findings: In order to evaluate the energy savings resulted from this installation, the two studies (simulation and real data) are followed by two parallel estimations of energy savings when compared to a theoretical electric energy expense in HVAC of a building with a more conventional building technology. The active water-flow glazing tackles the problem by flowing water through the chamber between glass panes; the windows become solar energy collectors, and a closed water circuit provides the building with the thermal inertia needed to prevent high temperature oscillations. Combining this emerging technology of active waterflow glazing with low-cost heating and cooling strategies such as geothermal exchangers, free cooling and seasonal heat storage would enable maximum use of daylight by a transparent glass facade and, at the same time, achieve Zero Energy Building performance. Applications: When compared to a traditional double-pane curtain-wall connected to an air-water heat pump, a combination of water-flow glazing and ground source heat pump proves to entail substantial energy savings (close to 40%) in a building’s overall cooling costs.

Laccase-Catalyzed Surface Modification of Thermo-Mechanical Pulp (TMP) for the Production of Wood Fiber Insulation Boards Using Industrial Process Water.

Low-density wood fiber insulation boards are traditionally manufactured in a wet process using a closed water circuit (process water). The water of these industrial processes contains natural phenolic extractives, aside from small amounts of admixtures (e.g., binders and paraffin). The suitability of two fungal laccases and one bacterial laccase was determined by biochemical characterization considering stability and substrate spectra. In a series of laboratory scale experiments, the selected commercial laccase from Myceliophtora thermophila was used to catalyze the surface modification of thermo-mechanical pulp (TMP) using process water. The laccase catalyzed the covalent binding of the phenolic compounds of the process water onto the wood fiber surface and led to change of the surface chemistry directly via crosslinking of lignin moieties. Although a complete substitution of the binder was not accomplished by laccase, the combined use of laccase and latex significantly improved the mechanical strength properties of wood fiber boards. The enzymatically-treated TMP showed better interactions with the synthetic binder, as shown by FTIR-analysis. Moreover, the enzyme is extensively stable in the process water and the approach requires no fresh water as well as no cost-intensive mediator. By applying a second-order polynomial model in combination with the genetic algorithm (GA), the required amount of laccase and synthetic latex could be optimized enabling the reduction of the binder by 40%.

An optimized water reuse and waste valorization method for a sustainable development of poultry slaughtering plants

The primary aim of this study is to find a solution to four of the major environmental and energy problems that currently exist in the poultry industry: (a) high water consumption, (b) emissions from excessively contaminated wastewater, (c) intensive consumption of electric and thermal energy, and (d) production of non-recoverable by-products and organic waste. It was decided that a wastewater treatment plant (WWTP) would be designed, which would, in addition to treating the water, create an effluent that meets the water quality standards, so that the water can be reused in plant processes. As part of this, a closed water circuit was created to reduce water consumption and the emission of wastewater. In order to address the issue of high-energy consumption and waste production, the construction of a biomethane production plant was proposed. Given that most of the waste is organic, the waste had to undergo anaerobic digestion processing. This resulted in biogas production, as well as subsequent use of the said biogas primarily as a thermal energy source, which was used to reduce external consumption. Both the WWTP and the biomass power plant required an anaerobic digester. The final aim of this study was to propose the implementation of a hybrid co-digestion system for wastewater and organic waste that would allow water to be treated and, at the same time, produce biogas, which could subsequently be used as an energy source.

A New Universal Wireless Transcutaneous Energy Transfer (TET) System for Implantable LVADs – Preliminary In Vitro and In Vivo Results

Purpose Present VAD driveline is the Achilles heal of long term VAD therapy. Infections and line damage are life threatening events. Previous experimental TET systems demonstrated limited efficiency, caused thermal injury and limited mobility. Leviticus-Cardio has developed a unique Coplanar Energy Transfer system (CET), and first in vitro and in vivo results using different VADs is presented. Methods and Materials The CET system contains: 1. An external unit consists of a transmitter coil belt around the body, rechargeable batteries and an external controller. 2. The implanted system has a receiver antenna, small backup rechargeable battery and miniature controller. The internal device is implanted in the recipient's body alongside the LVAD. This new aparatus seems to be easily implantable, avoids the risk of skin heating, and allows for full body motion. In vitro testing with various VAD models has been completed. Preliminary animal in vivo studies using a Jarvik 2000 pediatric VAD were performed successfully without the use of cardio pulmonary bypass. Results The in vitro testing using a closed water circuit with 4 comercial VADs (HeartMate II, CorAide, Jarvik-2000 Adult and Jarvik-2000 Pediatric) demonstrated stable operation by the CET system for more than 24 hours. We ran a full log for one life span of external and the rechargeable internal batteries. The in vivo testing in an acute porcine model revealed similar high efficiency for up to 9 hours after the implant, when the experiment had to be terminated. Conclusions This CET system is a promising new tool for future LVAD technology with reliable energy transfer, efficiency and consistency. If future testing will continue to support our findings, this device will allow to operate different LVADs safely, thus expanding LVAD applications with lower risk of morbidity and a much better quality of live. ResultPumpSpeed [RPM]Average Power [W]Efficiency [%]H.M. ll10K8.577-79Jarvik Ped.10K4.577-82Jarvik Ad.10K578-81CorAide6.8K1075-77In Vivo - Jarvik Ped.10K775

Evaluación y comparación de la eficiencia de dos sistemas de incubación de huevos de Genypterus chilensis (Guichenot, 1848)

The current trend in world aquaculture is towards the diversification of cultures, mainly native species. The red cusk eel Genypterus chilensis is a native Chilean species of high gastronomic demand and seasonal exploitation that is projected as a candidate for the development of farming technology. The objective of this study was to test the efficiency of two incubation systems for G. chilensis egg masses, one with a closed water circuit (SICC) and the other with an open water circuit (SICA). Efficiency was measured by the percentage of eggs hatched. Two assays were performed, measuring and comparing the percentages of egg fecundation and hatching in four replicates between the two incubation systems. Significant differences were only found between the percentages of fecundation of bioassay 2. On average, in bioassay 1, egg fecundation reached 81%, and the average of hatching for the SICC was 42.9 ± 34.5% and for the SICA was 0.0 ± 0.0%. Bioassay 2 had an average fecundation of 87.3 ± 2.6% for the SICC and 79.8 ± 3.2% for the SICA, and the average for hatching was 27.9 ± 33.7% for the SICC and 4.8 ± 5.6% for the SICA. Incubation parameters for maximum hatching were discussed and a proposal was made for improving the SICC system. The incubation system with a closed water circuit generated greater survival of G. chilensis eggs.

Evaluacion y comparacion de la eficiencia de dos sistemas de incubacion de huevos de Genypterus chilensis (Guichenot, 1848)

Actualmente la tendencia de la acuicultura mundial esta orientada hacia la diversificacion de los cultivos, principalmente de especies nativas. El congrio colorado Genypterus chilensis es un pez nativo de alta demanda gastronomica y explotacion estacional que lo proyecta como candidato para el desarrollo de su tecnologia de cultivo. El objetivo de este trabajo fue evaluar la eficiencia de dos sistemas de incubacion de masas de huevos de G. chilensis , uno con circuito cerrado de agua (SICC) y el otro con circuito abierto (SICA); su eficiencia fue medida por el porcentaje de eclosion de huevos. Dos ensayos fueron realizados midiendo y comparando los porcentajes de fecundacion y eclosion de huevos en cuatro replicas entre los dos sistemas, encontrandose solo diferencias significativas entre los porcentajes de fecundacion del bioensayo 2. El bioensayo 1 tuvo un 81% promedio de fecundacion de los huevos y el porcentaje promedio de eclosion para el SICC fue 42,9 ± 34,5% y para el SICA fue 0,0 ± 0,0%. El bioensayo 2 tuvo un porcentaje promedio de fecundacion de los huevos de 87,3 ± 2,6% para el SICC y 79,8 ± 3,2% para el SICA y el porcentaje promedio de eclosion para el SICC fue 27,9 ± 33,7% y para el SICA fue 4,8 ± 5,6%. Se discuten los parametros de incubacion para obtener una maxima eclosion y se entrega una proposicion para mejorar el sistema SICC. El sistema de incubacion con circuito cerrado de agua genero mayores sobrevivencias en los huevos de G. chilensis .

Study of Slime Water Concentration Measurement and Influencing Factors with Ultrasonic Attenuation Theory

With the increasing degree of mechanization coal mining, the coal proportion less than 0.5 mm grade was increased year by year in raw coal in our country, which increase the difficulty of the slurry water treatment. However, the treatment can reduce the concentration of Wash water, realize the closed water circuit. And the economy of water resources the reclaim of coal and the protection of ecological environment can be influenced. And the correct detection of slime water concentration is the basis of all work. At present, the gamma-ray detection method is used to test Coal Slurry water concentration, with which there are a lot of inconvenience. The ultrasonic technology is introduced to detect coal slurry water concentration. The ultrasonic attenuation rule in the slurry water and the factors of affecting the acoustic attenuation are researched. The solutions are brought up. Tests show that ultrasonic detection technology can replace the traditional gamma-ray method and has great practical value.

The Heater–Cooler Unit—A Conceivable Source of Infection

Even drinking water is contaminated with pathogenic microorganisms. This does not necessarily pose a risk for healthy individuals, but it may result in serious consequences in people with impaired immune systems. This is particularly valid if drinking water is used for medical purposes. The heater–cooler unit (HCU) connected to heat exchangers or blankets by tubing, the connection is closed water circuit that contains microorganisms and algae. While connecting the tubing to the heat exchanger, spilling of water cannot be avoided. Microbiological examinations showed that germs and particles pollute the units. Exposure to the patient and the OR equipment has the potential to increase the risk of infection should the HCU water come in contact with the patient. As a result of the high incidence of particle and algae in the HCU, malfunction occurs. Sampling shows >1000/mL CFU (colony forming units) at 36°C and 55/mL CFU at 20°C on average. The specific findings include Pseudomonas and Legionella. Disinfecting HCU is very difficult. Often HCUs do not provide any technology to reduce bacterial or other contamination. The instructions for use of oxygenators often exclude the use of disinfectants. Maintenance instructions for the HCU advocate the use of disinfectants that carry the risk of oxygenator damage and of heat exchanger leakage. The effect of chemical disinfectants and heat exchanger membranes have not been examined, they may impair heat exchanger permeability and function. As an alternative to chemical and thermal disinfection, we used the alternative method of filtration. Using a membrane filter element, we noticed a decreasing number of CFUs from 55 to sterile conditions at 20°C and from >1000 CFUs to 100 CFUs at 36°C (Figure 1). In addition, we noticed a removal of other particles and algae. In conclusion, we have demonstrated a technique that is simple to implement and effectively reduces the microbiological load of the water in the heater– cooler unit.

A HPMT based set-up to characterize scintillating crystals

Abstract We have developed a fully automatic measurement set-up, capable of measuring light yields arising from scintillating crystals in a linear range of about four orders of magnitude. The photodetector is a hybrid photomultiplier tube specially developed to optimize linear range and photon detection. Crystal and photodetector are temperature controlled by a closed water circuit, as this is essential when measuring low light yield scintillating crystals with a marked temperature dependence of their light yield. Gamma sources can be placed either on top or on the side of the crystal. In this latter case, the source can be automatically moved by a computer-controlled step motor to provide a uniformity profile of the light yield along the crystal. Tagged and not-tagged operation modes are possible. The whole set-up is computer-controlled in an effort to provide fast and reliable measurements, to characterize many crystals per day. This is important for the quality control of the lead tungstate crystals that will be applied in the electromagnetic calorimeter of the CMS-detector at the LHC at CERN.

古紙を知ろう 製紙業界における嫌気性排水・用水処理の適用

Since the beginning of the eighties, anaerobic effluent treatment plants have been applied in the paper industry. The UASB reactor has become the most popular reactor. It is operating on almost all types of paper industry effluents, but the largest numbers can be found in the paper recycling industry. When acid paper sizing was abandoned, circumstances for fresh water reduction im-proved considerably, so that process waters and resulting effluents became much more concentrated in COD.Increased water hardness, due to CaCO3 in the waste paper, causes heavy biomass flocs and granules. Mixing problems are overcome by the application of a new generation of reactors (IC reactors).Paper manufacturing often takes place at temperatures of 55°C, due to better dewatering in the press section and subsequent steam savings in the drying section. The high temperatures can he best achieved in closed water circuit. Biological process water treatment remain necessary in the closed circuit, due to contamination problems (odours).In order not to loose too much energy for cooling the water before the biological treatment, extensive research has been started for thermophilic treatment. This process could he quite attractive for several reasons. The first indications are quite positive. For the future, it is expected that many recycle/packaging grade mills will move to effluent-free operation with new cost-efficient in-line biological treatment concepts.

The feasibility of fast single-bit sampling for multi-point laser Doppler anemometry

Consideration is given to a number of aspects concerning the design and implementation of a simultaneous multi-point laser Doppler anemometry (LDA) system. The difficulties of data collection and processing for many channels is seen to be the principle limiting factor to system development, and a practical route making use of highspeed components for fast LDA signal sampling and storage, followed by fast Fourier transform (FFT) signal analysis in software is explored. A demonstration system is constructed consisting of ten optical channels arranged in a linear array, a single LDA sampling card and a controlling microcomputer, and the arrangement is applied to a closed water circuit. Received signals are compared with software-generated equivalents and the effect of various signal-to-noise ratios on the accuracy of a reconstructed velocity distribution is examined. The overall configuration is shown to provide a modular approach enabling a piecewise increase in the number of processing channels according to requirements.

Cod Removal in a Closed Water Circuit of a Papermill by an Anaerobic Fluidized Bed Reactor

In waste paper processing mills, entirely closed process water systems cause high specific polluting problems, deteriorate the quality of the paper produced and corrode the equipment. Operating an anaerobic fluidized bed on part of the circulating water could make it possible to achieve lower dissolved organic concentration in the closed process water system. Laboratory experiments have been carried out according to the following flow-sheet : Water circuit; Acidification tank; Fluidized bed. When the anaerobic treatment is added to the water circuit, COD removal is 75% in the circuit and 65% in the acidification tank. Consequently, until reaching steady state, the organic load entering the fluidized bed decreases continuously from 28.75 to 9.86 kg COD/m3 d−l without disturbing biomass activity. From a mass balance, a mathematical model is drawn to check the COD removal in the water circuit and study the transitory period. Efficient fluidized bed performances are achieved even with high organic load (28.75 kgCOD/m3d−1) 52% to 75% COD removal are obtained in the water circuit respectively within 75 and 24 hours. The treated water represents a very small part of the circulating water. To achieve 52% COD removal the equivalent of 0.5 m3/t produced paper is treated. For a 75% COD removal efficiency, treated flow rate is 2.6 m3/t produced paper.

Rugeley Dry Cooling Tower System

Steam power stations are one of the biggest users of water and the increasingly heavy demand for water, for all purposes, throughout the world has caused serious studies to be made of methods of providing a cooling facility for steam turbines independent of a water supply. The studies revealed that a system devised by Professor Heller provided the most economic and practical solution for large steam turbines. It uses the atmosphere as a heat sink for the turbine exhaust heat by a combination of jet condenser, closed water circuit, heat exchangers cooled by air and a cooling tower. Although there is a water circuit to be filled initially, no further water is required. The first application of the system—the dry cooling tower system—to a large turbine was designed and built by the English Electric Company Ltd for the C.E.G.B. at their Rugeley Power Station and this paper describes the project and its behaviour in service.

Corrosion in Low‐pressure Boilers

Corrosion problems in low‐pressure boiler plant systems arise chiefly in the following system components:— (i) Water Side of Boiler (Internal). (ii) Fire Side of Boiler (External). (iii) Boiler Chimney. This article discusses corrosion problems relating to low‐pressure steam boilers operating at a maximum pressure of 200 psi, space heating boilers operating on closed water circuit and domestic hot water boilers operating on a direct tap‐water circuit.