Cooling Tower Basin Research Articles

Black Material Deposition in Surface Facilities During Commissioning in Muara Laboh Geothermal Field

Muara Laboh geothermal field is located in West Sumatra, Indonesia. The installed capacity is 80-85 MWe and already accomplished the Commercial Operation Date (COD) in December 2019. Prior to COD, several programs were conducted: pre-commissioning and commissioning programs. During these activities, some findings were encountered and one of the major findings was the black material deposit at several spots. The black material found from HP separator drain, condensate drain port and then ended up beneath the cooling tower basin. Based on the laboratory analysis, the SEM-EDX data shows that the material dominated by magnetite (Fe-Ox) and pyrite (FeS2) for the strainer sample. Meanwhile, the sample from HP separator contains some amount of silica, Arsenopyrite, anhydrite, and carbon. The occurrence of Fe-Ox might indicate the source of the black material coming from industrial goods, which caused by steam flow activity during the pre-com and commissioning program. Thus, the fact that no black material found during well testing from all wells also supports the theory.

A novel system for the treatment of wastewater from a tomato processing plant with UV light

Abstract In tomato processing plants, the production of paste involves the use of heat to evaporate water to concentrate the tomato juice. The hot water isolated from the juice is then passed through cooling towers to cool it sufficiently before discharge. Recovery of excess and blowdown water from the cooling towers would decrease the net water demand of the plant and improve water efficiency. However, since this water has been exposed to the open air, it must be disinfected before reuse. This research investigated the use of a novel ultraviolet (UV) system to disinfect water from the cooling tower basins located at an industrial tomato processing facility. The objective was to assess, in situ, the disinfection system's performance with regards to its utility, and its ability and to treat wastewater generated in an operational, industrial-scale setting. Beyond typical wastewater microbial assays, 16S rRNA gene sequencing was employed to understand the bacterial communities present in the wastewater, and to screen for microorganisms that may pose a risk for water reuse in food processing facilities.

Combined Thermal-Hydro Power Generation: A Novel Approach of Plant Capacity Addition

This paper proposes a hydro-power plant which is coupled with cooling water system of 500MW e coal-fired thermal power plant to quantify the additional electric power and mitigate CO 2 emission. About 16.77m 3 /s of cooling water gravitationally flow from cooling tower basin to CW basin with 1.5 meter gross head difference for recycling it into condenser and auxiliary cooling water system in a 500MW e coal-fired thermal power plant. Maximum 195kW e hydro-power can be generated through installing a Kaplan turbine for plant capacity addition. Effect of gross head and flow rate variations are studied individually and result shows that power generation increases with head and flow. Hourly about 106.13 kg of coal and 47.94 kg of CO 2 emission can be reduced to generate 500MW e combined thermal-hydro electric power. Generation cost and payback period of hydro power are about 71.62 paisa/unit and 2.04 years respectively.

The ITER Heat Rejection Challenge

ITER is an international fusion facility being built in France to demonstrate the scientific and technological feasibility of fusion power. Fusion power at ITER is generated using a Tokamak machine in which burning plasma at temperatures of 150,000,000°C is confined within a vacuum vessel by magnetic fields. The enormous amount of heat generated by the Tokamak and its auxiliary systems is removed by the cooling water systems, consisting of the Tokamak Cooling Water System (TCWS), the Component Cooling Water System (CCWS), the Chilled Water System (CHWS), and the Heat Rejection System (HRS). These systems are designed to remove an initial peak heat load of about 1100MW.ITER is an experimental facility that will operate in a cyclical fashion. High levels of fusion power will be generated during repeated plasma pulses with specified durations. Heat produced by the fusion reaction will not be used to generate electricity, but will be rejected to the environment.The cyclical nature of the ITER machine presents distinct challenges to the design of the HRS which must reject normal facility heat loads plus large, intermittent heat loads from Tokamak pulse operations, while maintaining stable and predictable cooling tower basin water temperatures to meet the needs of cooling water system clients. This paper explores these challenges to the HRS design and describes the selected solutions.

Evaluation of coatings, mortars and mix design for protection of concrete against sulphur oxidising bacteria

Deterioration of concrete in cooling tower basins by microbiologically influenced corrosion (MIC) is a concern in geothermal power plants. The effect of supplementary cementitious materials, epoxy coatings, latex-modified mortars and calcium aluminate cement mortar for protecting concrete from MIC was investigated. Laboratory exposure tests to a particular type of sulphur and iron oxidising bacteria, Thiobacillus ferrooxidans, were performed to rank candidate materials and these were followed by field exposure tests of the best materials in a cooling tower basin. It was determined that partial replacement of cement with 40% blast furnace slag or 5% to 10% silica fume improved resistance to MIC. A replacement level of 60% slag resulted in similar performance to concrete made with ordinary Portland or sulphate resistant cement. Epoxy- and styrene butadiene latex-modified mortars offered protection to concrete but still underwent a degree of attack. Epoxy coatings were found to be effective in protecting concrete. Calcium aluminate cement mortar showed excellent durability in laboratory and field tests.

Disinfection of bacterial biofilms in pilot-scale cooling tower systems

The impact of continuous chlorination and periodic glutaraldehyde treatment on planktonic and biofilm microbial communities was evaluated in pilot-scale cooling towers operated continuously for 3 months. The system was operated at a flow rate of 10,080 l day−1. Experiments were performed with a well-defined microbial consortium containing three heterotrophic bacteria: Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. The persistence of each species was monitored in the recirculating cooling water loop and in biofilms on steel and PVC coupons in the cooling tower basin. The observed bacterial colonization in cooling towers did not follow trends in growth rates observed under batch conditions and, instead, reflected differences in the ability of each organism to remain attached and form biofilms under the high-through flow conditions in cooling towers. Flavobacterium was the dominant organism in the community, while P. aeruginosa and K. pneumoniae did not attach well to either PVC or steel coupons in cooling towers and were not able to persist in biofilms. As a result, the much greater ability of Flavobacterium to adhere to surfaces protected it from disinfection, whereas P. aeruginosa and K. pneumoniae were subject to rapid disinfection in the planktonic state.

Determination of Discharge Coefficients for Hydraulic Sparger Design

This paper provides design examples and summarizes a study on the determination of multiple free discharge orifice coefficients in a circular walled manifold for a variety of shapes and area projections. A simplified design procedure is presented which allows engineers to accurately maintain a given pressure and flow at the entrance to the sparger. The design provides for uniform flow across the cooling tower basin, and prevents an increase in back pressure or open channel flow within the sparger, minimizing the effect of surging or pressure fluctuations on upstream performance.

Current status of geothermal power plants at the Geysers, Sonoma County, California

Electric power in commercial quantities from geothermal steam has been produced at The Geysers in Sonoma County, California, since 1960. Four steam turbine-generator units have been installed with rated capacities of 12,000 kW, 14,000 kW, 28,000 kW, and 28,000 kW for a total current production capacity of 82,000 kW. The last unit went into operation in 1968. Two more units of 55,000 kW capacity each are under construction for completion in 1971. More units are tentatively planned; their construction depends on the success of future drilling operations. Development at the Geysers started in 1922 when the first steam well was drilled. Eight wells were drilled from that date through 1925. However, commercial development was not feasible at that time. Some steam was used at an adjacent resort for heating and also, through use of two small reciprocating steam engine-generators, lighting was provided until 1959 when connection was made to the P. G. and E. system. Present development started with well drilling in 1955 and agreement for the first unit was reached between P. G. and E. and the steam developers in 1958 with the unit going into operation in 1960. Continued success in drilling, a total of fifty-two wells that has greatly enlarged the known boundaries of the steam field, has resulted in the installation of more units as described previously. Actually, the boundaries of the steam field at The Geysers have not yet been clearly determined. Several ⪡step-out⪢ wells, some distance removed from existing production areas, have been successful. The design of Units 1 through 4 is essentially the same although the size varies. Each unit includes a non-extraction, condensing turbine taking steam at 80 or 65 lb per square inch gauge, an exhaust duct leading to a barometric condenser located outside and above the turbine building, cooling tower supply pumps to move water from the condenser hotwell to an induced draft cooling tower, and condenser supply pumps to move water from the cooling tower basin to the condenser. Units 5 and 6, under construction, will be similar in design to the existing units except that the steam inlet pressure will be 100 psig and the condenser, while still in direct contact, will not be barometric but will be located under the turbine. There will be no condenser supply pumps, as the water will return from the cooling towers under vacuum. As the steam flow is greater than the cooling tower evaporation, there is excess water produced in the cycle which must be disposed of. As this water is contaminated, principally with ammonia, sulfides, and boron, its disposal presents a serious problem. Injection wells are currently being used for this purpose. The steam supply is slightly superheated and contains ammonia, carbon dioxide, and hydrogen sulfide as principal contaminants, amounting to 0.3% to 2.0% of the steam. These present corrosion problems to plant equipment, but have been dealt with by the proper selection of materials. The four units, which are located in two power plant buildings, are designed to run at constant load unattended. Operators and maintenance personnel are normally at the plant during eight hours in the daytime only. Electric power production at The Geysers has proven to be economical, and further development is to be expected if sufficient steam supply and reserves are developed.