Environmental management of coastal cooling water discharges in Hong Kong

1998 ◽  
Vol 38 (8-9) ◽  
pp. 267-274 ◽  
Author(s):  
S. W. Y. Ma ◽  
C. S. W. Kueh ◽  
G. W. L. Chiu ◽  
S. R. Wild ◽  
J. Y. Yip
Keyword(s):  
Hong Kong ◽  
Management Practices ◽  
Cooling System ◽  
Cooling Water ◽  
Water Systems ◽  
Ecological Impacts ◽  
Toxic Chemicals ◽  
Marine Biota ◽  
Cooling Systems ◽  
Large Power

Seawater cooling systems are an essential feature of Hong Kong's large public, institutional, commercial and industrial complexes. Over 25 million cubic metres of seawater are used for cooling purpose everyday. Biofouling, scaling and corrosion are common operational problems encountered. These are generally combatted through the use of chemicals such as chlorine and other antifouling/anticorrosion chemicals which are toxic to marine organisms and potentially harmful to the environment. Due to the continuous daily discharge of large amounts of cooling seawater everyday, significant quantities of heat is dissipated and potentially toxic chemicals are released to the coastal environment. A comprehensive survey of the cooling water system operations in Hong Kong was commissioned by the Hong Kong Environmental Protection Department in 1996. The survey results indicate that some 93 major cooling water systems are currently operating in the territory, about 80% of which are located around Victoria Harbour. The majority of the cooling water systems are the once-through type, causing a temperature rise of 3–5°C above ambient at discharge points. Cooling water discharges from large power plants, on the other hand, may have a discharge temperature increase of 8–10°C above the ambient which is close to the upper thermal tolerance limit of most marine biota. Chlorine and amine-/surfactant-based biocides are the most commonly used antifouling/anticorrosion chemicals. An estimated 11,000 tonnes of chlorine are released into the marine environment of Hong Kong each year by the cooling systems. Chlorine and its reactive by-products are known to be toxic to marine life even at very low concentrations. Despite the large dilution capacity of seawater, chlorinated discharges may cause adverse ecological impacts, particularly in the vicinity of large cooling water outfalls. Sound management of Hong Kong's cooling systems is necessary to allow efficient use of seawater for cooling, while minimizing its adverse environmental impact. Such management practices include improved cooling system design, effective operation and maintenance for biofouling control. Overdosing of toxic chemicals should be avoided and there is a need to regularly monitor the effluents to ensure compliance with discharge standards.

Assessment of thermal behavior of a cooling system to reduce thermal fatigue cracks in aluminum injection molds

2020 ◽  
pp. 75-86
Author(s):  
Sergio Antonio Camargo ◽  
Lauro Correa Romeiro ◽  
Carlos Alberto Mendes Moraes
Keyword(s):  
Thermal Fatigue ◽  
Cooling System ◽  
Fatigue Cracks ◽  
Cooling Water ◽  
Thermal Conditions ◽  
Thermal Gradients ◽  
Ansys Software ◽  
Cooling Systems ◽  
Thermal Fatigue Cracks ◽  
Number Of Cycles

The present article aimed to test changes in cooling water temperatures of males, present in aluminum injection molds, to reduce failures due to thermal fatigue. In order to carry out this work, cooling systems were studied, including their geometries, thermal gradients and the expected theoretical durability in relation to fatigue failure. The cooling system tests were developed with the aid of simulations in the ANSYS software and with fatigue calculations, using the method of Goodman. The study of the cooling system included its geometries, flow and temperature of this fluid. The results pointed to a significant increase in fatigue life of the mold component for the thermal conditions that were proposed, with a significant increase in the number of cycles, to happen failures due to thermal fatigue.

Recapturing Net Positive Suction Head Margins in Boiling Water Reactor Emergency Core Cooling Systems

2017 ◽  
Author(s):  
Alan J. Bilanin ◽  
Andrew E. Kaufman ◽  
Warren J. Bilanin
Keyword(s):  
Cooling System ◽  
Cooling Water ◽  
Boiling Water ◽  
Boiling Water Reactor ◽  
Cooling Systems ◽  
Water Reactor ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Core Cooling ◽  
Reactor Pressure

Boiling Water Reactor pressure suppression pools have stringent housekeeping requirements, as well as restrictions on amounts and types of insulation and debris that can be present in the containment, to guarantee that suction strainers that allow cooling water to be supplied to the reactor during a Loss of Coolant Accident remain operational. By introducing “good debris” into the cooling water, many of these requirements/restrictions can be relaxed without sacrificing operational readiness of the cooling system.

scholarly journals Comparison between OCl−-Injection and In Situ Electrochlorination in the Formation of Chlorate and Perchlorate in Seawater

2019 ◽  
Vol 9 (2) ◽  
pp. 229 ◽  
Author(s):  
Jongchan Yi ◽  
Yongtae Ahn ◽  
Moongi Hong ◽  
Gi-Hyeon Kim ◽  
Nisha Shabnam ◽  
...  
Keyword(s):  
Reaction Time ◽  
Electrode Material ◽  
Power Plants ◽  
Cooling System ◽  
Cooling Water ◽  
Injection System ◽  
No Production ◽  
Cooling Systems ◽  
Environmentally Friendly Method

To prevent biofouling from occurring in the cooling systems of coastal power plants, chlorine is often added to the cooling water. In this study, we have evaluated the fate of the total residual oxidants and the formation of inorganic chlorination byproducts including ClO3− and ClO4− during in situ electrochlorination with seawater. Then, the results were compared with those during direct OCl−-injection to seawater. The in situ electrochlorination method based on Ti/RuO2 electrodes produced much less ClO3−, while a similar level of total residual oxidants could be achieved with a reaction time of 5 min. Moreover, no ClO4− was observed, while the direct OCl−-injection system could still result in the production of ClO4−. The less or no production of ClO3− or ClO4− by the electrochlorination of seawater was mainly attributed to two reasons. First, during the electrolysis, the less amount of OCl− is available for ClO3− formation. Secondly, the formation of ClO3− or ClO4− is affected by the electrode material. In other words, if the electrode material is carefully chosen, the production of harmful reaction byproducts can be prevented or minimized. In short, based on the results from our study, electrochlorination technology proves to be a marine environmentally friendly method for controlling biofouling in the pipes of the cooling system in a coastal power plant.

scholarly journals Legionella pneumophila in cooling water systems: Report of a survey of cooling towers in London and a pilot trial of selected biocides

1982 ◽  
Vol 88 (3) ◽  
pp. 369-381 ◽  
Author(s):  
J. B. Kurtz ◽  
C. L. R. Bartlett ◽  
U. A. Newton ◽  
R. A. White ◽  
N. L. Jones
Keyword(s):  
Legionella Pneumophila ◽  
Slow Release ◽  
Pilot Trial ◽  
Cooling Water ◽  
Water Systems ◽  
Quaternary Ammonium Compound ◽  
Ammonium Compound ◽  
Intermittent Treatment ◽  
Cooling Systems ◽  
Level 1

SummaryFourteen recirculating cooling water systems were surveyed during the summer, 1981, to see what factors might influence the prevalence ofLegionella pneumophila. The effect on the organism of three anti-microbials was studied, each in two systems, by intermittent treatment at two week intervals.L. pneumophilawas isolated from six of the 14 cooling systems at the beginning of the trial but by the end was present in ten. An association was found between the presence of the organism and the concentration of dissolved solids, and chlorides and the pH. There also appeared to be associations with exclusion of light and higher water temperatures.Repeated tests on eight untreated systems showed that two were consistently infected, three became and remained infected, one was infected on a single occasion and two were never infected withL. pneumophila. Treatment of a contaminated system, either with a 10 p.p.m mixture of a quaternary ammonium compound and tributyltinoxide or slow release chlorine briquettes (maximum recorded free chlorine level 1·2 p.p.m.), did not eliminated legionellae. Treatment of two infected towers with a chlorinated phenol (100 p.p.m.) eliminated legionellae for at least three days, but after 14 days the organism was again found.

Casing Distortion of GE Frame 3 Gas Turbines

2003 ◽  
Author(s):  
Ryan D. Mitchell ◽  
Henry L. Bernstein ◽  
Peggy L. Talley
Keyword(s):  
Gas Turbines ◽  
Oil And Gas ◽  
Cooling System ◽  
Cooling Water ◽  
Oil And Gas Industry ◽  
Water Systems ◽  
Water Cooling ◽  
Gas Industry ◽  
Turbine Casing ◽  
Water Cooling System

A study of casing distortion in General Electric MS3002 gas turbines used in the oil and gas industry revealed significant distortion for MS3002 Models C through G. The primary distortion problem was ovalization of the turbine casing, which could occur in either the horizontal or vertical directions. Malfunctioning of the water cooling system, or improper disassembly and assembly procedures can cause casing distortion. The MS3002 Models A-G gas turbines have water cooled turbine casings, and malfunctioning of their cooling water systems, regardless of distortion, is also a significant problem.

scholarly journals Heuristic Framework for Sustainable Cooling Water Systems Operations in Oil Facilities

2021 ◽  
Vol 15 ◽  
pp. 1-16
Author(s):  
Mustafa Hashim ◽  
Mimi Haryani Hassim ◽  
Denny KS Ng ◽  
Denny KS Ng
Keyword(s):  
High Efficiency ◽  
Cooling System ◽  
Water System ◽  
Cooling Water ◽  
Water Systems ◽  
Design Stage ◽  
Project Schedule ◽  
Residential Areas ◽  
Oil Companies ◽  
Cooling Water System

To meet the growing demand for cleaner environment from the society, most leading oil companies have committed to preserve environment via reduction of greenhouse gases, water and soil pollution as well as the use of natural resources. In most of the oil facilities, they required massive cooling systems to cool down process streams in order to meet the process requirements. The most common cooling system in oil facilities is evaporative cooling water system (ECWS) as such system has high efficiency. Cooling water is commonly used in offices and residential areas. However, the cooling water system is one of the utility systems that generates high environmental impacts due to high consumption of power, water and chemicals. Therefore, it is important to optimize the system in the early design stage of the project to operate in the most effective and efficient condition. In reality, many efforts may be missed out due to loose project definition, inexperience design engineer, hectic project schedule, or resource constraint. Therefore, in order to overcome the previous limitations, this paper presents a comprehensive heuristic improvement framework for cooling water systems in oil operating facilities.

scholarly journals Cooling Systems Design in Hot Stamping Tools by a Thermal-Fluid-Mechanical Coupled Approach

2014 ◽  
Vol 6 ◽  
pp. 545727 ◽  
Author(s):  
Tao Lin ◽  
Hong-Wu Song ◽  
Shi-Hong Zhang ◽  
Ming Cheng ◽  
Wei-Jie Liu
Keyword(s):  
Significant Influence ◽  
Cooling System ◽  
Hot Stamping ◽  
Cooling Water ◽  
Systems Design ◽  
Simulation Method ◽  
Fluid Simulation ◽  
Geometrical Parameters ◽  
Cooling Systems ◽  
Quenching Effect

Hot stamping tools with cooling systems are the key facilities for hot stamping process of Ultrahigh strength steels (UHSS) in automotive industry. Hot stamping tools have significant influence on the final microstructure and properties of the hot stamped parts. In serials production, the tools should be rapidly cooled by cooling water. Hence, design of hot stamping tools with cooling systems is important not only for workpieces of good quality but also for the tools with good cooling performance and long life. In this paper, a new multifield simulation method was proposed for the design of hot stamping tools with cooling system. The deformation of the tools was also analyzed by this method. Based on MpCCI (Mesh-based parallel Code Coupling Interface), thermal-fluid simulation and thermal-fluid-mechanical coupled simulation were performed. Subsequently, the geometrical parameters of the cooling system are investigated for the design. The results show that, both the distance between the ducts and the distance between the ducts and the tools loaded contour have significant influence on the quenching effect. And better quenching effect can be achieved with the shorter distance from the tool surface and with smaller distance between ducts. It is also shown that, thermal expansion is the main reason for deformation of the hot forming tools, which causes the distortion of the cooling ducts, and the stress concentration at corner of the ducts.

Water Quality and the Discharge of Cooling Water into Rivers, Lakes and Coastal Waters

1983 ◽  
Vol 15 (10) ◽  
pp. 15-30
Author(s):  
R. Gasparini
Keyword(s):  
Coastal Waters ◽  
Power Plants ◽  
Cooling System ◽  
Cooling Water ◽  
Fish Population ◽  
Point Of View ◽  
Water Bodies ◽  
Experimental Investigations ◽  
Cooling Systems ◽  
Receiving Water

This paper resumés some of the main findings and conclusions of a study group on cooling water problems (1) set up by UNIPEDE (2). The paper represents only the personal point of view of the author, in particular as chairman of the above mentioned group. The basic aim of the work was the study of the effects of the discharge of cooling water in the receiving water bodies (rivers, lakes and coastal waters). This type of assessment permits a more balanced and pragmatic approach to aspects such as thermal pollution, entrainment, impingement and pollution by antifouling agents. The first part of the paper deals with the problem of damage to organisms entering a cooling system. An important factor in assessing the meaning of such aspect is the growing evidence that there is no reduction in fish population of the receiving water body associated with the operation of modern power plants despite the catch in the once through-cooling systems due to entrainment and impingement, that can be minimized, but not avoided. The second part deals with the different methods of fouling prevention in power plants, with their possible environmental effects in the receiving water bodies. The third part is a comprehensive review of the results of aquatic impact studies at power plants, that is the results of many experimental investigations carried out in the field to evaluate the effects of the operation of once through cooling systems sited on rivers, lakes, or coastal waters.

scholarly journals TEMPERATURES OPTIMIZATION OF TWO-CIRCUIT CLOSED COOLING SYSTEM OF SHIP'S POWER PLANT

2020 ◽  
pp. 175-183
Author(s):  
Konstantin Yu. Fedorovskiy ◽  
Nadezhda K. Fedorovskaya
Keyword(s):  
Heat Exchanger ◽  
Power Plant ◽  
Heat Exchangers ◽  
Closed Loop ◽  
Cooling System ◽  
Cooling Water ◽  
Cooling Systems ◽  
Additional Heat ◽  
Temperature Head ◽  
Optimal Value

    The issues of creating environmentally friendly highly reliable closed-loop cooling systems are considered in the paper. The achievement of these qualities is ensured by the rejection of cooling water intake. The analysis of various coolants of the power installation requiring cooling is carried out. It is shown that for the cooling of a number of coolants it is advisable to create double-circuit cooling systems. This requires the introduction of an additional heat exchanger and the separation of the temperature head between the cooled coolant and seawater. The authors suggest an approach that makes it possible to distribute this temperature head between the circuits optimally. This procedure involves comparing various heat exchangers based on their reduced area. A nomogram is presented to determine the optimal value of the temperature head.

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