Condenser Tubes Research Articles

Application of on Line Chemical Cleaning for Stainless Steel Tube Condenser in a Power Plant

According to the characteristics of stainless steel material and scale composition of condenser in a power plant, nitric acid was used as cleaning medium, and corrosion inhibitor was added to inhibit the corrosion of nitric acid on stainless steel. On line chemical cleaning was carried out on the condenser without shutdown. The scale removal efficiency and corrosion rate met the requirements of DL/T957-2017, and the terminal difference of condenser recovered to the optimal value after cleaning.

Experimental study of condensation heat transfer characteristics on metal foam wrapped tubes under sloshing conditions

Metal foam wrapped tube has the advantages of large specific surface area, and thus it has great potential to enhance the condensation heat transfer for marine shell and tube condensers, which have the requirements of "high compactness" and "high reliability" under sloshing conditions. In the present study, the effects of the metal foam pore density and the sloshing conditions on the condensation heat transfer on metal foam wrapped tubes were experimentally investigated. The pore density of metal foam covers the widely used structure ranging from 5 PPI to 40 PPI; the sloshing conditions include six-freedom motions of surging, swaying, heaving, rolling, pitching and yawing; the sloshing displacement ranges from 0 to 120 mm; the sloshing angle ranges from 0 to 12°; and the sloshing frequency ranges from 0 to 0.33 Hz. The experiment results show that the condensation heat transfer coefficients of metal foam wrapped tubes increase firstly and then decrease with the increase of PPI, and the 10 PPI metal foam wrapped tube shows the optimal condensation performance. The rolling motion has significant effect on the condensation heat transfer of metal foam wrapped tube, while the other five sloshing motions have negligible effect on the condensation heat transfer of metal foam wrapped tube. With the increase of rolling angle from 0 to 12°, the condensation heat transfer performance of 10 PPI and 20 PPI metal foam wrapped tube gradually increases and the increase rate of the condensation heat transfer coefficient is up to 12%; while the condensation heat transfer performance of metal foam wrapped tube with 5 PPI increases as the rolling angle is larger than 10°. With the increase of rolling frequency, the condensation heat transfer performance of metal foam wrapped tube decreases, and the decrease rate of the condensation heat transfer coefficient is up to 8%.

Indirect validation of fluid-to-fluid scaling criteria for modeling steam condensation based on empirical correlations and CFD simulations

Several nuclear reactor designs have adopted passive safety systems with condensation inside horizontal tubes, such as the Passive Auxiliary Feedwater System (PAFS) of the APR+, the new generation of the Korean-Standard Pressurized Water Reactors (PWR). Performing steam condensation experiments under high-pressure conditions is needed for the design and the realistic prediction of the condensation phenomena in such systems. To avoid the costs and technical complexities associated with experimentation at high-pressure conditions, a fluid-to-fluid scaling method to model high-pressure steam condensation with a simulant fluid, refrigerant for instance, had been developed. It was determined that the liquid-to-vapor density ratio, the Froude number, and the vapor Reynolds number should be preserved in order to guarantee the flow regime and heat transfer similarity between prototypes and models. The scope of the current work is to validate the developed scaling criteria. Due to the limitation of test data of different fluids with comparable test parameters, indirect validation is proposed based on two approaches. The first approach is based on empirical correlations, in which test data from one fluid are transferred to the equivalent conditions of the other fluid, the transferred data are then compared with condensation correlations to check the validity of the scaling method. The second approach is based on CFD calculations. A CFD model, using the commercial CFD code STAR-CCM+, for the simulation of condensation in hotizontal tubes is developed. The Fluid Film model is used for modeling the condensate film thickness and development. For modeling the phase change process, source and sink terms are introduced to the continuity, momentum, and energy equations at the interface between the vapor and the condensate film. The developed CFD model is then applied in the scaling criteria validation by using it to simulate the condensation phenomena of different models in one fluid and compare its results with the corresponding experimental data in other fluid. The validation results show good agreement between prototypes and their equivalent models, and show good feasibility and reasonable accuracy of the proposed scaling criteria.

In-situ phase separation to improve phase change heat transfer performance

Phase change is widely applied in thermal-power conversion, cooling and thermal management, influencing efficiency, safety and cost of energy systems. The complicated mass, momentum and energy exchanges between two-phases causes large pressure drops, critical heat fluxes and flow instabilities. Here, a review on phase separation principle for phase change heat transfer is provided. The phase separation principle is presented in a theoretical form. Design and operation of phase separation for evaporator, condenser and heat pipe are commented. Because phase separation assigns pathways for liquid and vapor, it improves pool boiling performance and eliminates flow instability for micro-evaporator. For micro-condenser, the lined pin fins array creates liquid and vapor passages. The expanded liquid passage adapts increased flow rate to increased flow passage area for liquid. Pin fins are effective for filmwise condensation to increase heat transfer coefficients at low cost of pumping power. Phase separation for macro-condenser was fulfilled by suspending mesh screen membrane tube in condenser tube to confine vapor in annular region, yielding enhanced thin film condensation. Phase separation was commented on smart heat pipe. Superhydrophilic evaporator and superhydrophobic condenser generate nucleate mechanism, achieving increased heat transfer coefficients when heat loads increase. Perspective of phase separation was discussed.

Implementation of a new empirical model of steam condensation for the passive containment cooling system into MARS-KS code: Application to containment transient analysis

For the Korean design of the PCCS (passive containment cooling system) in an innovative PWR, the overall thermal resistance around a condenser tube is dominated by the heat transfer coefficient of steam condensation on the exterior surface. It has been reported, however, that the calculated heat transfer coefficients by thermal-hydraulic system codes were much lower than measured data in separate effect tests. In this study, a new empirical model of steam condensation in the presence of a noncondensable gas was implemented into the MARS-KS 1.4 code to replace the conventional Colburn-Hougen model. The selected correlation had been developed from condensation test data obtained at the JERICHO (JNU Experimental Rig for Investigation of Condensation Heat transfer On tube) facility, and considered the effect of the Grashof number for naturally circulating gas mixture and the curvature of the condenser tube. The modified MARS-KS code was applied to simulate the transient response of the containment equipped with the PCCS to the large-break loss-of-coolant accident. The heat removal performances of the PCCS and corresponding evolution of the containment pressure were compared to those calculated via the original model. Various thermal-hydraulic parameters associated with the natural circulation operation through the heat transport circuit were also investigated.

Desain Dan Pembuatan Alat Destilasi Asap Cair (Liquid Smoke)

Liquid smoke is a condensate liquid from the pyrolysis of coconut shells which contains the main constituent compounds of acids, phenols, and carbonyls, so it is widely applied as a natural preservative in food and provides sensory characteristics in the form of aroma, colour, and a distinctive taste in food products and as an anti-bacterial. The research objective was to design, manufacture, and test the liquid smoke distillation apparatus. The method used in this research is an experimental method where the activities carried out include designing, making, and testing. The result is that the furnace is made based on the results of the initial design with a height of 61 cm, width 41 cm and length 41 cm. The top of the furnace is conical with a cone height of 34 cm. The condenser tube is rectangular in shape with a width of 40.5 cm, length 40.5 cm and a height of 60.5 cm. the condenser tube serves to accommodate water which is used as a cooling medium. The inside of the condenser tube contains ¾ inch pipe which is formed into a rectangular spiral into 5 stacks. The pipe functions to flow the smoke from the combustion products from the gas phase into a liquid by cooling it with water as a medium. the manufacture of the liquid smoke distillation device has been carried out by the design, but there are some minor changes in the process of making the distillation device. Tests are carried out using raw materials, namely coconut shells and coconut fibers as fuel. Tests carried out with variations in the time and volume of liquid smoke generated from the distillation device. The test results from the liquid smoke distillation tool obtained 400 ml of liquid smoke from the distillation in 2 hours

High-performance energy-saving miniature loop heat pipe for cooling compact power semiconductors

A miniature loop heat pipe (mLHP) is developed to cool compact wide bandgap power semiconductors with a high heat flux (≥30 W/cm2) and high allowable operating temperature (≤250 °C) for the first time. Since the mLHP consists of an evaporator (15 × 16 × 3 mm), a condenser (12 × 12.5 × 2 mm), and transport tubes (100 mm), it can be mounted on a small product equivalent to the size of a gaming smartphone. To achieve high heat flux performance, the mLHP uses Shirasu porous glass for the wick and ethanol for the working fluid. Moreover, for the condenser, heat dissipation is enhanced using a thin copper plate (60 × 60 × 0.5 mm), a thin aluminum cold plate (35 × 20 × 3 mm), or a small cooling fan (17 × 17 × 3 mm). When the condenser dissipates heat using the thin aluminum cold plate, the mLHP achieves a maximum heat-transport performance of 15 W (60 W/cm2) in the horizontal attitude. At the maximum heat load, the heat-source temperature, evaporator temperature, and system thermal resistance at 15 W are 249.8 °C, 142.2 °C, and 0.72 °C/W, respectively. Additionally, the heat transfer coefficient of evaporation at the evaporator is approximately 24,000 W/m2/K. The proposed steady-state numerical model is consistent with the experimental results, excluding the condenser part, with a relative error of 7%.

Technoeconomic analysis of thermoelectric power plant condensers with nonwetting surfaces

This paper investigates the dynamic performance and economic benefits of using nonwetting tube surfaces fabricated by electrodeposition process in thermoelectric power plant condensers. Nonwetting surfaces enhance performance by reducing fouling resistance and promoting dropwise condensation of steam on the shell side. Using a thermal resistance network of a shell and tube condenser, detailed parametric studies are presented to investigate the effects of design parameters and operating parameters on the annual condenser performance and its impact on the net electric energy output of a representative 550 MW coal-fired power plant. A cost model is presented to evaluate the technoeconomic benefits of the enhanced condenser design in a unified manner, in terms of a new levelized cost of condenser (LCOC) metric. The model is coupled with a numerical optimization method to identify optimal nonwetting condenser tube designs that minimize LCOC. The results show optimal cooling water flow velocity of 2.5 m/s and tube diameter of 0.032 m (0.025 m) for nonwetting (plain) condenser tube surfaces that exhibit dropwise (filmwise) condensation. Condensers with nonwetting surfaces are shown to reduce LCOC by a factor of 2.5 and 1.7, respectively, compared to plain titanium and aluminum-brass tubes.

Failure analysis of admiralty brass tubes in a surface condenser: a case study at the petrochemical industry

ABSTRACT The surface condenser in the steam turbine plays an essential role during the condensation process. Failure of surface condenser tubes is a critical factor for its efficiency and lifetime. This paper presents the failure of a surface condenser's admiralty brass tubes from a petrochemical plant in Indonesia after four years out of twenty years of expected lifetime. Eddy Current inspection results show some of the leaks were in the condensing zone. The characteristics of ammonia corrosion were found after visual and SEM examinations. Examination using stereo and metallurgical microscopes showed that the tubes' external surface experienced corrosion, grooving attack, and significant wall thinning. SEM observation at the edge of the baffle revealed the preferential attack at the alloy's grain boundaries. Water quality analysis indicated high ammonia concentration because the excess amount of Elimin-Ox oxygen scavenger in the water can produce ammonia that corroded the tubes, leading to leakage and failure.

Study of Non-condensable Gas, Fouling, and Plugging Effects on Condenser Performance Using NTU-Effectiveness Analytic Method and 2D Numeric Simulation

This paper was objected to determine the effect and how sensitive the variation of the percentage of non-condensable gas, fouling thickness and the amount of plugging to the performance of the condenser and the steam turbine power output. This study was conducted using the NTU-effectiveness analytical method, and specifically for the study of the effects of non-condensable gas combined with numerical simulations to obtain the value of the condensation heat transfer coefficient as an input for analytical calculations. The study was conducted with a variation of the percentage of non-condensable gas 0% (new and clean), 2%, 5%, and 8%, with fouling thickness 0 µm, 2 µm, 5 µm, and 8 µm, and the amount of plugging 0%, 5%, 10%, and 15%. 2D numerical simulation was used to determine the impact of non-condensable gas percentage variation on the value of the condensation heat transfer coefficient on the outside of the tube, both qualitatively and quantitatively along the circumference of the condenser tube. The results of this study were, the greater the percentage of non-condensable gas, the thicker the fouling layer, and the more amount of plugging, would have an impact on decreasing the net turbine work. Consequently for new and clean conditions, the percentage of non-condensable gas were 2%, 5%, 8%, fouling thickness 2 um, 5 um, 8 um, and the amount of plugging were 5%, 10%, 15%, resulting in net turbine work to 202.55 MW, 192.08 MW, 189.08 MW, 185.85 MW (non-condensable gas), 200.05 MW, 196.01 MW, 192.08 MW (fouling), 195.2 MW, 185.27 MW, and 174.77 MW (plugging). A financial loss simulation was also carried out due to the decline in electricity sales affected by the decreasing of power plant’s net turbine work.

Effect of Fins spacing on the Performance Evaluation of a Refrigeration System using LPG as Refrigerant

In this paper, experimental analysis was carried out on a vapour compression system by varying the parallel tube condenser fins spacing under the same atmospheric condition in a selected Refrigeration and Air-conditioning laboratory to examine the performance characteristics of the refrigeration system. The fins spacing were 2, 4 and 6 mm using Liquefied petroleum gas (LPG) as working fluid with a mixture proportion of 17.2% isobutene, 56.4% butane, 24.4% propane. The result shows that the coefficient of performance of the system when working with condenser fins spacing of 2 mm was 28.8 and 35.9% higher compared to when the system worked with the fins spacing of 4 and 6 mm respectively. Energy consumed by the single hermetic compressor when the system worked with condenser fins spacing of 2 mm reduced by 16.4 and 18.7% compared to when the refrigerator worked with fins spacing of 4 and 6 mm respectively. The pull down time of the cooling system was attained in 2 hours 45 minute with minimum evaporator temperature of -13 °C while working with 30 g mass charge of LPG.

Protective layer dissolution by chlorine and corrosion of aluminum brass condenser tubes of a nuclear power plant

The pitting and erosion corrosion of aluminium brass (Al-brass) condenser tubes in a seawater cooled nuclear power station was investigated. Inadequate ferrous sulphate dosing and relatively excess chlorine concentrations have caused the corrosion of the Al-brass tubes. Microscopic studies and surface chemical analysis were carried out to understand the mechanism of corrosion. Optical, stereozoom and SEM microphotographs showed intense pitting and typical errosion corrosion pattern of Al-brass. XRD analysis showed that the major corrosion product was copper chloride (parachamite). Detailed XPS study has provided valuable supportive data to eloborate on the mechanism of Al-brass chemical corrosion.

On the introduction of macrophytophagous fish into the of Berezovskaya-1 power plant cooling pond

One of the frequently encountered problems of small cooling ponds at SDPPsis rapid eutrophication and the associatedintensified development of phytoplankton — “hyperblossom” and overgrowth of water bodies with higher aquatic vegetation. As a result of hyperflowering, a huge amount of detritus is deposited on the condenser tubes, reducing the efficiency of the station. The authors analyzed the situation in the cooling pond of Berezovskaya-1 power plant, which was designed with a number of deviations from the “Sanitary rules for the preparation of the reservoir bed and canals for flooding and their sanitary protection”. In this regard, active eutrophication of the reservoir began, which by 2001 reached the stage of “hyper-flowering”. Higher aquatic vegetation has spread in shallow waters and formed “islands” around the peat floating up from the bottom. Among the known measures to combat plant forms, the most environmentally friendly and economically acceptable method of cleaning water bodies with the help of amelioration fish — the silver carp microphytophage and grass carp macrophytophage — is recognized as the most environmentally friendly and economically acceptable. With the undoubted advantage of this method, it has weaknesses, for example, long-term consequences for aboriginal ichthyocenoses in connection with the introduction of competing fish. Due to the fact that, with a sufficient amount of plant feed, grass carp is not a food competitor for the fish and introduced species of the Bereshskoye reservoir and cannot reproduce in the natural environment, it will not reduce the production of local ichthyofauna. Itis recommended to take into account that with a decrease inichthyomass, the infested objectis able to significantly expand the range of food due to benthic and planktonic animals. At the same time, systematic control over the size of the grass carp population should become a mandatory measure, providing for an increase in the commercial catch at the first signs of suppression of aquatic phytocenoses. The authors have calculated the norms of planting material for stocking the cooling pond at Berezovskaya-1 power plant and the fish-breeding indicators that can be obtained 4 years after stocking the cooling pond with grass carp.

Corrosion Inhibitation of Cu-Zn Alloys in NaCl Solution Using Isatin

TThe effect of isatin on the corrosion of Cu-20%Zn-2%Al (alloy I) and Cu-31% Zn (alloy II) in NaCl solution has been studied using different electrochemical techniques [open circuit, potentiodynamic, and impedance spectroscopy (EIS)]. The two copper alloys were used in condenser tubes of heat exchanger for power station plant in Egyptian financial and industrial company Assiut factories. The steady state potential Es.s values increase to more negative values by increasing NaCl concentration which indicated that the destruction of pre-immersion passive film formed on the Cu-Zn surfaces. The corrosion rate of the two alloys decreased by increasing concentration of isatin, which indicated the effect of isatin as a corrosion inhibitor. The inhibition efficiency of isatin in 0.1M NaCl solution was 88.5 % in alloy I and 73.9 % in alloy II at a concentration 0.01M of isatin. The significant inhibition processes due to the adsorption characteristics of isatin on the two alloys surface. The chemical composition of alloy I was more resist to corrosion in NaCl solution than the chemical composition alloy II due to presence of Al.

Global optimization of the design of horizontal shell and tube condensers

The literature about heat exchanger design optimization encompasses a large number of papers, but only a small fraction is dedicated to phase change systems. This article presents for the first time a linear design optimization approach for horizontal shell and tube condensers that guarantees global optimality. Area is minimized using an integer linear model. This model is obtained from a mathematical reformulation of the original nonlinear thermofluid dynamic equations and it is solved using integer linear programming (ILP). Because of the linear nature of the proposed model, the global optimum is always attained, without the need of using specialized global solvers, selection of good initial estimates or drawbacks related to convergence issues. Numerical results indicate that the proposed approach can present solutions with lower heat transfer areas than two design procedures presented in chemical process design textbooks.

Performance study of fog desalination system coupled with evacuated tube solar collector

This study presents an experimental and theoretical investigation of a fog desalination system powered by an evacuated tube solar water heater (ETSWH). This system is composed of a high-pressure fog pump, two fog nozzles each of diameter 0.1 mm, condenser, finned tube heat exchanger, evaporation and condensation duct, and a natural flow ETSWH of ten evacuated tubes integrated with a horizontal storage tank. The effect of different operating parameters on the performance of the system was experimentally investigated. In the theoretical part of this study, the operating conditions of the ETSWH were investigated to optimize the performance of the whole system. Theoretical results showed that increasing water mass in the storage tank increases the efficiency of ETSWH and decreases water temperature. The recommended water mass in the storage tank is 81 kg/m2 of solar collector area tilted at the optimum tilt angle, while the water flow rate from the storage tank should not exceed 0.0032 kg/s for each m2 of ETSWH. From present experimental results and according to the salinity tests, it is recommended to operate the desalination system at inlet water temperature higher than 55 °C.

Design improvement and experimental study on shell and tube condenser for bio-oil recovery from fast pyrolysis of wheat straw biomass

In this study, the design improvement was done in a shell and tube condenser for improved heat transfer and condensation of bio-oil vapour. The developed condenser has split shell and segmental baffles, which divide the shell in various zones and condensate collection points. The fast pyrolysis of wheat straw was done and the bio-oil vapour condensate collected from various outlets located at bottom of condenser shell. From experimental results it was found that production of bio-oil increased from 10.2 to 20.8% with increase in cooling water flow rate from 1000 to 2500 L/h; but, further increasing it beyond 2500 L/h provide marginal effects on production of bio-oil. The production of bio-oil increased from 15.2 to 20.7% as sweep gas flow rate was increased from 20 to 40 L/min at 2500 L/h of cooling water flow rate. But, further increase in sweep gas flow rate beyond 40 L/min resulted in to decrease in production of bio-oil. The novelty of this work is development of improved condenser with segmental baffles, which help in fractional condensation of bio-oil vapour, split shell for cleaning of outer surface of the cooling water tubes and compact design of condenser for optimal condensation of bio-oil.

A new cooling strategy for edge computing servers using compact looped heat pipe

The rapid development of distributed edge computing system demands urgently that the thermal management solution for server CPUs in micro-data centers have the characteristics of compact structure, high performance, maintenance-free, and energy saving. This paper focuses on a new cooling concept enabled by a compact loop heat pipe. Through removing compensation chamber, selecting a spindle-shaped evaporator structure with aid of an auxiliary gradient sintered capillary wick connecting the condenser and the evaporator, this new proposed loop heat pipe module can provide high reliability operation, meanwhile maintaining high thermal performance. Under forced air cooling, it is demonstrated that the 4 mm thick loop heat pipe module with finned tube condenser could dissipate a heat load of 150 W under a wide fan voltage range from 12 V to 24 V at tested directions when the chip junction temperature was below 85 °C, and could manage a heat load up to 275 W without dry-out. The proposed new loop heat pipe module with finned tube condenser is a potential solution to cool edge-computing server CPUs.

Investigation on the effect of thermal properties by change in materials of the air conditioner condenser tube using simulation

Abstract Extended Surfaces widely known as “Fins” are the surfaces that are extended from the actual body or system to enhance the heat transfer rate. Generally, the heat transfer from the body dissipates either to the environment or from the environment by increasing the surface area for the convection heat transfer to take place. In this present research work, CAD model of a segment of condenser tube of air conditioner is taken to perform thermal analysis and simulation on the application of constant internal applied temperature. Alongside the change in the materials of the extended surface as well as the tubing of the condenser is also analyzed. The experiment results shows five different iterations based on the change in material of the corresponding thermal body of extended surface and the condenser tube of the air conditioner. The paper majorly focuses on the temperature, heat flux and thermal gradient of the condenser tube segment. From the results of simulation software it is observed that the change in material has made significant effects on the thermal gradient of the condenser tube and concluded that the high strength aluminum fin and copper tube combination is more distinct compared to other material combinations.

Effects of R134a Saturation Temperature on a Shell and Tube Condenser with the Nanofluid Flow in the Tube Using the Thermal Efficiency and Effectiveness Concepts

The work’s objective is to analyze the influence of the saturation temperature of the R134a refrigerant on the thermal performance of a shell and tube type condenser, with water and aluminum oxide (Al2O3) nanoparticles flowing into the tube. For analysis, the heat exchanger is subdivided into three regions: subcooled liquid, saturated steam, and superheated steam. The shell and tube heat exchanger assumed as the basis for the study has 36 tubes, with rows of 4 tubes in line and three passes into the tube in each region. The parameters used to analyze the performance are efficiency and effectiveness, through variations of quantities such as saturation temperature, the nanofluid’s mass flow rate, fraction in the nanoparticles’ volume, and the number of passes in the tube in each region of the heat exchanger. The obtained results demonstrate that the efficiency is relatively high in all the analyzed situations. In each saturation temperature, the effectiveness can be increased by introducing fractions of nanoparticles in the water or increasing the number of passes in the tube.