scholarly journals Prediction of Strength Properties of Filling Packets in Selected Cooling Towers

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3840
Author(s):  
Monika Chomiak ◽  
Maciej Rojek ◽  
Józef Stabik ◽  
Małgorzata Szymiczek
Keyword(s):  
Tensile Strength ◽  
Cooling Tower ◽  
Operating Time ◽  
Degradation Process ◽  
Strength Properties ◽  
Operating Conditions ◽  
Polymer Materials ◽  
Cooling Towers ◽  
Reference Samples ◽  
Degree Of Degradation

The operating conditions of thermoplastic polymer materials determine the changes in their functional properties. Accelerated aging tests do not give a full picture of the changes taking place in the polymer material, hence the conclusions drawn on the basis of exposure of these materials to damaging effects in real operating conditions are particularly important. The aim of the study was to determine the degree of degradation of polypropylene films used in the drainage blocks of cooling towers in a selected power plant in the Silesian voivodship, which allowed forecasting the operating time over a period of 10 years. A number of 600 mm high drip blocks were tested, on which 300 mm high blocks were mounted. The tests were carried out on films subjected to the aging process in the conditions of continuous operation of a cooling tower (almost 100% humidity). The water flow is accompanied by heat exchange, the side effect of which is deposits formation on the surface of the drip blocks, negatively affecting the operation of the cooling tower. The degree of degradation resulting from operational aging was assessed on the basis of the strength properties determined in the static tensile test, thermogravimetric analysis and FTIR spectra. Changes in properties during operation were determined on the basis of the obtained results of the strength tests, which were compared with the tensile strength and elongation at break of reference samples (not subjected to aging in the operating conditions of cooling tower drip blocks). The obtained results were related to the properties of the reference samples not subjected to the degradation process. Based on the collected data, the tensile strength and deformation at fracture after a 10-year service life were predicted.

CHARACTERIZATION OF PHYSICAL AND MECHANICAL PROPERTIES OF BIODEGRADABLE FOAM FROM MAIZENA FLOUR AND PAPER WASTE FOR SUSTAINABLE PACKAGING MATERIAL

2020 ◽  
Vol 5 (8) ◽  
Author(s):  
Yusuf Arya Yudanto ◽  
Isti Pudjihastuti
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Operating Time ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Raw Material ◽  
Visual Appearance ◽  
Paper Waste ◽  
Best Value

Biodegradable Foam (Biofoam) production is an effort to reduce plastic waste in Indonesia. This product is made to replace Styrofoam, whose raw material is carcinogenic in the form of styrene which cannot be dissolved by the digestive system and is difficult to excrete through urine or feces which can trigger the growth of cancer in the long term and is harmful to the environment. Biofoam in this study is made from cornstarch with the addition of cellulose taken from paper waste. Based on the research that has been done, cornstarch-based biofoam with the addition of cellulose from paper waste as a biofiller can affect the physical and mechanical characteristics of the biofoam produced. The biofoam with a starch:cellulose ratio of 13:10 grams resulted in the best value of water adsorption in the amount 47.26%, also give the best result on tensile strength value and biodegradability value in the amount of 4.548 MPa and 11.943%. The addition of cellulose to the biofoam mixture in an appropriate amount will reduce the water absorption value of the biofoam. Because cellulose can cover the cavities generated by the starch expansion process in the biofoam. Therefore, the addition of cellulose also affects the mechanical properties of biofoam, namely tensile strength. Where the low filler composition in the biofoam will increase the tensile strength, but when the filler composition has passed an optimum point, the filler particles will experience agglomeration thereby reducing the tensile strength of the biofoam product. The variation in operating conditions in the manufacture of starch-based biofoam with the addition of a biofiller in the form of cellulose from paper waste did not significantly affect it. The variation in operating conditions only affects the visual appearance of the biofoam produced. Biofoam samples with the best visual appearance were produced at an operating temperature of 160 ? with an operating time of 30 minutes. Where high temperatures can affect th

Computer Simulation of Transport Phenomena in Evaporative Cooling Towers

1988 ◽  
Vol 110 (2) ◽  
pp. 190-196 ◽  
Author(s):  
D. J. Benton ◽  
W. R. Waldrop
Keyword(s):  
Power Plants ◽  
Field Data ◽  
Cooling Tower ◽  
Operating Conditions ◽  
Cooling Towers ◽  
Governing Equations ◽  
Cooling Process ◽  
Transfer Processes ◽  
Finite Integral ◽  
Simultaneous Heat

A computer model of the simultaneous heat, mass, and momentum transfer processes occurring throughout an entire cooling tower is described in this paper. The model includes the flexibility to analyze the several configurations, fill arrangements, and flow distributions commonly used by the power industry. The fundamental governing equations are solved using a finite-integral technique to provide a quasi-two-dimensional description of the flow and cooling process within the tower. The model has been successfully compared with field data from cooling towers at three TVA power plants as well as data from other utilities. Each of these towers was significantly different in design, thereby demonstrating the versatility of the model for correctly predicting the cooling performance of mechanical and natural draft towers, as well as crossflow and counterflow orientations, for a range of meteorological and plant operating conditions.

Improving the energy efficiency of a 110 MW thermal power plant by low-cost modification of the cooling system

2018 ◽  
Vol 29 (2) ◽  
pp. 245-259 ◽  
Author(s):  
Milica Jović ◽  
Mirjana Laković ◽  
Miloš Banjac
Keyword(s):  
Energy Efficiency ◽  
Power Plant ◽  
Cooling Tower ◽  
Cooling System ◽  
Thermal Power ◽  
Ambient Air ◽  
Electric Power System ◽  
Operating Conditions ◽  
Cooling Towers ◽  
Tower System

The electric power system of the Republic of Serbia relies mostly on lignite-fired thermal power plants, with 70% of the total electricity generation. Most of these plants are over 30 years old, and investment in their modernization is necessary. The energy efficiency of the 110 MW coal-fired power plant in which the condenser is cooled by the mechanical draught wet cooling towers system is analyzed in this paper. Attention is primarily devoted to operating conditions of the cold end of the plant, i.e. to the interrelationship of the condenser and cooling towers. Most important parameters that affect the operation of the cooling towers system are ambient air temperature and relative humidity, specific mass flow rate, and temperature of cooled water. With the existing cooling system, the overall energy efficiency of the plant is low, especially in the summer months, even less than 30%, due to adverse weather conditions. By upgrading existing cooling tower system by adaptation of two additional cooling tower cells, overall energy efficiency can be increased by 1.5%. The cooling tower system rehabilitation investments payback period is estimated to be less than one year. Static method for economic and financial assessment is used.

scholarly journals Assessment of Material Durability of Steam Pipelines Based on Statistical Analysis of Strength Properties—Selected Models

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3633
Author(s):  
Jarosław Piątkowski ◽  
Bożena Gajdzik ◽  
Aleksander Mesjasz
Keyword(s):  
Tensile Strength ◽  
Vickers Hardness ◽  
Operating Time ◽  
Operational Reliability ◽  
Strength Properties ◽  
Working Time ◽  
Prognostic Models ◽  
Significance Level ◽  
The Impact ◽  
Material Durability

The paper presents a research method concerning the application of statistical prognostic models for assessment of material durability and operational reliability of steel for steam pipelines, whose operation has exceeded the working time of 100,000 h. Decisions on the admission of long-lived materials to work for power industry results from extensive diagnostic examinations are based on the results of tests of mechanical properties, microstructure degradation, and corrosion processes. Considering the economic reasons and available data published in diagnostic reports, the determination of failure-free operating time of steam pipelines is based on the results of static tensile tests—tensile strength (Rm); conventional yield point (Rp); elongation (A) and Vickers hardness (V), correlated with the operating time and the media type (fresh steam and secondarily super-heated steam) for the most sensitive element of a pipeline, namely the elbow. The results of changes in strength properties during operation are presented in the form of graphs of the analyzed material feature vs. operating time in the range from zero hours (for a new material) to 300,000 h, taking into account the impact of random and systematic disturbances within the adopted tolerance limits. It has been found that because of the R2 factor and significance level in the t-Student test for regression and correlation coefficients, exponential, hyperbolic and quadratic models are best fitted to empirical points. Based on the tensile strength results (Rm), it has been found that the forecast time of the steam pipeline ranges from 193,400 to 258,300 h. Taking the yield strength (Rp) into account, it has been ascertained that the time ranges from 225,000 to 293,000 h, and for the working time forecast of steam pipelines based on Vickers hardness results, it ranges from 192,100 to 246,800 h.

A Comparative Study of Mechanical Properties of Biodegradable PBSAT and PA Gillnets in Norwegian Coastal Waters

2019 ◽  
Author(s):  
Biao Su ◽  
Heidi Moe Føre ◽  
Eduardo Grimaldo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Comparative Study ◽  
Seawater Temperature ◽  
Field Tests ◽  
Degradation Process ◽  
Polymer Materials ◽  
Elongation At Break ◽  
The North ◽  
Polybutylene Succinate

Abstract This paper presents a comparative study of mechanical properties of biodegradable PBSAT (polybutylene succinate co-adipate-co-terephthalate) and conventional polyamide (PA) gillnets used in Norwegian fisheries. Field tests were performed to simulate abandoned, lost, or otherwise discarded fishing gear. Changes in mechanical properties of PBSAT and PA nets in two Norwegian coastal environments were studied. Samples of biodegradable PBSAT gillnets and PA gillnets were placed inside modified lobster pots at four different locations: two outside the island Hitra in the middle of Norway and two outside Tromsø in the north of Norway. For each pot, seawater temperature was logged each hour, and net samples were retrieved for analyses at 3 to 9 months intervals. Tensile strength testing was performed to determine and compare mechanical properties of biodegradable and PA monofilaments and gillnets. Comparative analyses were conducted, aimed at investigating the different behaviors of biodegradable material and conventional PA material, and the possible influence of seawater temperature on the degradation process of biodegradable PBSAT gillnets. Reduced tensile strength and elongation at break, and a slight increase in stiffness was observed for both PA and PBSAT monofilaments after the field trial at Hitra, indicating degradation of both polymer materials. After 25 months immersion in seawater, the PBSAT gillnets exhibited a significant reduction of tensile strength due to seawater exposure (35%), and the tensile strength of PBSAT gillnets was then 26% lower than the average strength of the PA net samples.

Performance Curves for Mechanical Draft Cooling Towers

1975 ◽  
Vol 97 (4) ◽  
pp. 503-508 ◽  
Author(s):  
G. F. Hallett
Keyword(s):  
Cooling Tower ◽  
Operating Conditions ◽  
Cooling Towers ◽  
Design Point ◽  
Performance Curves ◽  
Bid Evaluation ◽  
Analytical Verification

This paper presents cooling tower theory and methods for analytical verification of manufacturers’ guaranteed performance curves for mechanical draft cooling towers. Both ASME PTC-23 and Cooling Tower Institute Bulletin ATP-105 are being revised and both test codes have historically used performance curves as a means of evaluating cooling tower capacity. Techniques and methods are given for calculating performance curves for both counterflow and crossflow type cooling towers. These procedures can be used during bid evaluation to assess and predict tower performance at various operating conditions other than the design point.

scholarly journals Energy efficiency indicators of cooling towers

2018 ◽  
Vol 11 (3) ◽  
pp. 217-221
Author(s):  
E. A. Lapteva ◽  
A. G. Laptev ◽  
M. L. Farakhov
Keyword(s):  
Mass Transfer ◽  
Energy Efficiency ◽  
Transfer Coefficient ◽  
Thermal Efficiency ◽  
Cooling Tower ◽  
Polymer Materials ◽  
Cooling Towers ◽  
Efficiency Criterion ◽  
Industrial Enterprises ◽  
Film Type

For selecting optimal regimes and design characteristics, an energy efficiency criterion of a mass transfer apparatus is considered, and on its basis, some particular cases of energy efficiency criteria for cooling towers, including the cases with a structured counter-current film-type packing, are obtained. The criteria include heat transfer efficiency in the gas and liquid phases, as well as kinetic characteristics of the process of cooling the water in blocks of film-type packings. Expressions are given for determination of thermal efficiencies in the gas (air) and liquid (water) phases of the cooling tower. Three notations for the energy efficiency criterion of cooling towers are obtained. In the first notation, the efficiency criterion is written down using the thermal efficiency of cooling the water; in the second notation, it is written down using the thermal efficiency of heating the air; in the third notation, it is written down via the transfer coefficient (mass transfer) and mean driving force in the form of an enthalpy difference. A notation of writing down the energy efficiency criterion for a film-type packing in the cooling tower with a volumetric mass transfer coefficient is presented. Irrigator blocks filled with structured film-type contact devices of various designs having an irrigation density of 12 m3/m2h and an air speed of 1.5 m/s are considered. Results of calculations of five types of structured packings are presented: tubular packing made of polyethylene net; metal packings VACU-PAK, PIRAPAK G, “Inzhekhim” IRG and segmentary-structured packing “Inzhekhim”. Values are obtained of the criterion of energy efficiency of these packings for cooling the water as well as the required height of irrigator blocks for a given temperature regime and hydraulic load. Values of the power expended for supplying the air to the irrigator blocks are determined and a histogram is plotted. It is concluded that modern domestic and foreign metal packings have high thermal and hydraulic efficiency and are recommended for use in mini-cooling towers (except for tubular packings made of polyethylene net). For reducing the cost of irrigator blocks, these can be made of polymer materials. Then such blocks of irrigators are recommended for creating a contact between the phases in large-scale cooling towers, which will significantly improve the efficiency of cooling the water at thermal power plants and industrial enterprises.

Increased dryness after pressing and wet web strength by utilizing foam application technology

TAPPI Journal ◽  
2016 ◽  
Vol 15 (11) ◽  
pp. 731-738 ◽  
Author(s):  
KARITA KINNUNEN-RAUDASKOSKI ◽  
KRISTIAN SALMINEN ◽  
JANI LEHMONEN ◽  
TUOMO HJELT
Keyword(s):  
Tensile Strength ◽  
Guar Gum ◽  
Paper Industry ◽  
Reference Sample ◽  
Strength Properties ◽  
Cellulose Microfibrils ◽  
Application Technology ◽  
Ethylene Vinyl Alcohol ◽  
Wet Pressing ◽  
Web Strength

Production cost savings by lowering basis weight has been a trend in papermaking. The strategy has been to decrease the amount of softwood kraft pulp and increase use of fillers and recycled fibers. These changes have a tendency to lower strength properties of both the wet and dry web. To compensate for the strength loss in the paper, a greater quantity of strength additives is often required, either dosed at the wet end or applied to the wet web by spray. In this pilot-scale study, it was shown how strength additives can be effectively applied with foam-based application technology. The technology can simultaneously increase dryness after wet pressing and enhance dry and wet web strength properties. Foam application of polyvinyl alcohol (PVA), ethylene vinyl alcohol (EVOH), carboxymethyl cellulose (CMC), guar gum, starch, and cellulose microfibrils (CMF) increased web dryness after wet pressing up to 5.2%-units compared to the reference sample. The enhanced dewatering with starch, guar gum, and CMF was detected with a bulk increase. Additionally, a significant increase in z-directional tensile strength of dry web and and in-plane tensile strength properties of wet web was obtained. Based on the results, foam application technology can be a very useful technology for several applications in the paper industry.

Case study: Theoretical calculation model and variable condition analysis research on the water-splashing noise for natural draft wet cooling towers

2020 ◽  
Vol 68 (2) ◽  
pp. 137-145
Author(s):  
Yang Zhouo ◽  
Ming Gao ◽  
Suoying He ◽  
Yuetao Shi ◽  
Fengzhong Sun
Keyword(s):  
Theoretical Model ◽  
Sound Pressure Level ◽  
Water Droplet ◽  
Water Distribution ◽  
Sound Pressure ◽  
Cooling Tower ◽  
Distribution Patterns ◽  
Calculation Model ◽  
Pressure Level ◽  
Cooling Towers

Based on the basic theory of water droplets impact noise, the generation mechanism and calculation model of the water-splashing noise for natural draft wet cooling towers were established in this study, and then by means of the custom software, the water-splashing noise was studied under different water droplet diameters and water-spraying densities as well as partition water distribution patterns conditions. Comparedwith the water-splashing noise of the field test, the average difference of the theoretical and the measured value is 0.82 dB, which validates the accuracy of the established theoretical model. The results based on theoretical model showed that, when the water droplet diameters are smaller in cooling tower, the attenuation of total sound pressure level of the water-splashing noise is greater. From 0 m to 8 m away from the cooling tower, the sound pressure level of the watersplashing noise of 3 mm and 6 mm water droplets decreases by 8.20 dB and 4.36 dB, respectively. Additionally, when the water-spraying density becomes twice of the designed value, the sound pressure level of water-splashing noise all increases by 3.01 dB for the cooling towers of 300 MW, 600 MW and 1000 MW units. Finally, under the partition water distribution patterns, the change of the sound pressure level is small. For the R s/2 and Rs/3 partition radius (Rs is the radius of water-spraying area), when the water-spraying density ratio between the outer and inner zone increases from 1 to 3, the sound pressure level of water-splashing noise increases by 0.7 dB and 0.3 dB, respectively.

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