Condensate Pump Research Articles

Experience gained from the development and results from tests of the equipment of the Kalinin NPP Unit 4 regeneration and intermediate steam separation and reheating system

The equipment of the Kalinin NPP Unit 4 regeneration, intermediate separation, and steam reheating (ISSR) systems is described and the results of their static and dynamic tests are presented. It was shown from an analysis of test results that the equipment of the regeneration and ISSR systems produce the design thermal and hydraulic characteristics in static and dynamic modes of its operation. Specialists of the Central boiler-Turbine Institute Research and Production Association have developed procedures and computer programs for calculating the system of direct-contact horizontal low-pressure heaters (connected according to the gravity circuit arrangement jointly with the second-stage electrically-driven condensate pumps) and the ISSR system, the results of which are in satisfactory agreement with experimental data. The drawbacks of the layout solutions due to which cavitation failure of the pumps may occur are considered. Technical solutions aimed at securing stable operation of the equipment of regeneration and ISSR systems are proposed. The process arrangement for heating the chamber-type high-pressure heaters adopted at the Kalinin NPP is analyzed. The version of this circuit developed at the Central Boiler-Turbine Institute Research and Production Association that allows the heating rate equal to 1°C/min to be obtained is proposed.

The influence of composition shift on organic Rankine cycle (ORC) with zeotropic mixtures

In the medium-temperature and low-temperature energy utilization, organic Rankine cycle (ORC) is one of the most technically feasible methods. In order to improve temperature mismatch in the process between constant temperature phase change and varying temperature heat source, organic Rankine cycle with zeotropic mixtures is put forward. The characteristics of temperature glide for zeotropic mixtures during evaporation and condensing processes lead to better temperature match with varying temperature heat source and heat sink, and therefore result in a lower system’s irreversibility and higher system performance. This paper mainly discusses the influence of composition shift on organic Rankine cycle with zeotropic mixtures. Evaporator, condenser, expander and feed pump models are respectively developed, and then the circulating composition is calculated, based on which, the system parameters and performance of organic Rankine cycle with zeotropic mixtures are obtained in the case of composition shift that means that the circulating composition is different from the charge composition. The results show that composition shift significantly influence the performance of organic Rankine cycle with zeotropic mixtures, which will result in a lower output work of expander, a higher power consumption of pump, a lower net output work and lower thermal efficiency. Meanwhile, it also discusses the local composition shift characteristic in the process of phase change and effects of charge and charge composition on composition shift.

Analysis of Heat Pump Condenser's Performance using the Mathematical Model and a Numerical Method

this article aims to investigate the performance of the heat pump's condenser and functionality, suitability of the steady-state mode mathematical model and the used numerical method. The heat transferred through the condenser is the performance of the condenser. The condenser is plate exchanger. The refrigerant is R 134a and the heated medium is water. This wide-range study investigates the condenser's performance depending on four independent external variables. The independent external variables are: inlet temperature of the refrigerant, refrigerant mass flow rate, the water inlet temperature and the water mass flow rate.The investigation is carried out by using a steady state mode mathematical model with lumped parameter. The model consists of two parts. Part one describes mathematically the cooling of the superheated vapor, while the second part describes the condensation itself. The physical model is simple, only the plate condenser and the input, output parameters are included. This article does not take into consideration the compressor and circulating pump model. That remains the subject of future investigation. The results can be represented in three-dimensional graphics. For example, it shows the changes of heat transfer in the condenser depending on the refrigerant mass flow rate and the water mass flow rate.

Research of the cavitation performance of the condensate pump

Condensate pump is an important part of power plant circulation systems, which is used to pump condensate water. Because the condensate water pressure is very low, the first impeller of the condensate pump must have a good cavitation performance. Numerical simulation was employed to study the first impeller cavitation performance. The first impeller was set in the condensate pump barrel, and the double suction casing was kept, the parts after the double suction casing was simplified as tube. The simplicity can guarantee the inlet and outlet conditions of the impeller. Based on the RANS and SST k − ω turbulence model, CFD software was used to simulate the condensate pump at different working conditions. The numerical simulation shows that cavitation occurred at the suction side of the blades closing to the leading edge. The cavitation performance of the impeller was predicted based on the numerical calculation. Comparing with the experimental results, the numerical simulation result is smaller than that of the experiment in small flux, and the cavitation performance trend is agreed with that of the experiments.

Cavitation performance evaluation for a condensate pump

Cavitation in a condensate pump with specific speed of 95 m·m3s−1·min−1 was treated in this study. Cavitation performance for the pump was tested experimentally, and the steady state cavitating flows in the pump impeller were simulated by RANS method as well as a homogeneous cavitation model. It is noted that cavitating flow simulation reasonably depicted cavitation development in the pump. Compared to the tested results, the numerical simulation basically predicted later performance drops due to cavitation. Unfortunately, the cavitation simulation at the operation condition of 50% best efficiency point could not predict the head drop up to 3%. By applying the concept of relative cavity length cavitation performance evaluation is achieved. For better application, future study is necessary to establish the relation between relative cavity length and performance drop.

Labyrinth of High Parameter Valve Technology Application and Prospects in the Power Plant

In order to solve the domestic sub and super-critical unit import the high cost of procurement of high parameters of valves and valve operation in the common issues such as defects, and introduces the new valve of the Sino-ROK cooperative project--the labyrinth of high parameter control valve. First elaborates its structure characteristics, the core technology and application, and introduces concrete application for the settlement of condensate water pump recirculation valve defect. And we can see the labyrinth of high parameter control valve important role and development prospects in the future power plant.

Creating a Common Safety Culture

Guest editorial Most people who work in the oil and gas industry know what a “permit to work” is. A blue permit indicates that it covers “cold” work—work with no potential to create a naked flame, hot surface, spark, or explosion. Having a permit ensures that the job site is safe for the team to do its work, that the team understands the potential risks of the work it is planning to do, and that it agrees to put suitable controls in place. I spoke recently at the Piper 25 Conference, a 3-day event held in Aberdeen to mark the 25th anniversary of the Piper Alpha disaster that killed 167 people on board the oil platform in the North Sea. On display at the conference was a copy of Cold Work Permit 23434. The tattered paper was found in the accommodation module that was recovered from the seabed. The permit was for the replacement of a relief valve on the B condensate pump. It was this work that was at the heart of the initial release and explosion when the operators tried to start the pump even though it was not ready. The rest, tragically, is history. It begs an obvious question and a supplementary one: Could something similar happen again and, if so, can we do anything to reduce the chances of it happening? The oil and gas industry has made huge advances in safety management over the past 25 years. The goal-setting regime, safety cases, and verification schemes have been hugely beneficial. We have greater collaboration and everyone now talks about safety as being important and most people genuinely believe it. However, the industry is still experiencing too many serious events which, if we are unlucky, could easily result in another tragedy. We are a global industry in which good practices are shared across our operations. The loss of life in any country has to be as unacceptable as a tragedy on our own doorstep. Over the past 25 years since Piper Alpha, there have been more than 25 multi-fatality accidents in our industry. In June, two people died in an accident on a gas platform in the Dutch sector of the North Sea. Last year, three died in an explosion in the Gulf of Mexico (GOM) and 11 died in the Deepwater Horizon explosion in the GOM in 2010.

Experimental Research on a Heat Pump Water Heater Using Low Pressure Steam as Heat Source

Heat recovery of low pressure steam in steam condenser of thermal power plant was attractive because of its great economy and environmental value. This paper reported the experimental investigation results on the application of a heat pump water heater (HPWH) using low pressure steam in steam condenser as heat source. The working principles and features of the prototype heat pump were introduced. The effects of various parameters, including water flow rate and inlet temperature of heat pump condenser were investigated. Influence of vacuum pump on HPWH was also discussed. Results show that performance of HPWH is governed strongly by the change of water flow rate and inlet water temperature of heat pump condenser and vacuum pump. Maximum outlet water temperature of the test HPWH is 65°C and the maximum coefficient of performance (COP) is 4.5.

Build up of off-diagonal long-range order in microcavity exciton-polaritons across the parametric threshold

We report an experimental study of the spontaneous spatial and temporal coherence of polariton condensates generated in the optical parametric oscillator configuration, below and at the parametric threshold, and as a function of condensate area. Above the threshold we obtain very long coherence times (up to 3 ns) and a spatial coherence extending over the entire condensate (40 μm). The very long coherence time and its dependence on condensate area and pump power reflect the suppression of polariton-polariton interactions by an effect equivalent to motional narrowing.

Development of new-generation pumps for the feed system of large power units

Main results from design developments of a sequential totality of condensate, booster, and feed pumps for thermal power units of the gigawatt class are described. The presented design solutions are innovative in nature and are aimed at achieving better energy efficiency, higher reliability, and longer service life of the main-cycle pumps.

작동변수에 따른 R744용 해양온도차 발전 사이클의 엑서지 분석

본 논문은 R744용 해양온도차 발전 시스템의 운전변수에 대한 최적의 설계를 위해서 엑서지효율을 이론적으로 분석하였다. 본 연구에서 고려된 작동변수로는 과열도와 과냉각도, 증발온도와 응축온도, 터빈과 펌프 효율 등이다. 분석한 결과를 요약하면 다음과 같다. R744용 해양온도차 발전 사이클의 증발온도, 과열도, 터빈효율, 펌프효율이 증가할수록 엑서지 효율은 증가한다. 그러나 응축온도와 과냉각도는 증가할수록 엑서지 효율이 감소한다. 이 중에서 증발온도의 변화가 R744용 해양온도차 발전 사이클의 엑서지 효율에 가장 크게 영향을 미치고, 펌프효율이 가장 적게 영향을 미친다. 따라서 R744용 해양 온도차 발전 사이클의 엑서지 효율을 증가시키기 위해서는 증발온도를 표층수 온도에 가장 근접하게 증가시키는 것이 유리하다.

Cavitating flow investigation inside centrifugal impellers for a condensate pump

In order to investigate the effect of blade inlet angle on centrifugal pump cavitation performance, numerical simulation of cavitating turbulent flow is conducted for a condensate pump with different impellers based on SST k−ω turbulence model and a mixture cavitation model. The results indicate that for a condensate pump having meridional section with larger area at blade leading edge compared with conventional pumps, the reverse flows inside the blade-to-blade channels are not negligible. It is noted that large incidence at blade leading edge is helpful to improve the cavitation performance for the pump. The possible reason may be the growth of cavities inside the impeller has less influence on the flow in the channel between two neighboring blades. Further, uniform incidence angle along the blade leading edge is preferable for the improvement of cavitation performance.

운전조건에 따른 R744용 해양온도차 발전 사이클의 성능 특성

In this paper, the cycle performance analysis for condensation and evaporation capacity, total work and efficiency of ocean thermal energy conversion power system using R744 (CO2) is presented to offer the basic design data for the operating parameters of this system. The operating parameters considered in this study include superheating and subcooling degree, evaporation and condensation temperature, pump and turbine efficiency. The main results were summarized as follows : The evaporation capacity of R744 increases with superheating and subcooling degree, but decreases with the increasing condensation temperature. The total work increases with superheating and subcooling degree of R744, but decreases with the increasing evaporating temperature. And, the efficiency increases with subcooling and superheating degree, but decreases with the increasing condensation temperature. Therefore, superheating and subcooling degree, evaporation and condensation temperature and pump and turbine efficiency of R744 OTEC power system have an effect on the evaporation and condensation capacity, total work and efficiency of this system. With a thorough grasp of these effect, it is necessary to design the OTEC power cycle using R744. Key w ords: R744(CO2), OTEC(Ocean Thermal Energy), Performance analysis

Rarefied gas dynamics aspects of pharmaceutical freeze-drying

Freeze-drying is a low-pressure, low-temperature condensation pumping process widely used in manufacture of bio/pharmaceutical products. Because of the need to avoid the aggressive evaporation drying, typical operating pressures in freeze-drying are below 100 Pa. Understanding relevant rarefied flow physics can help improve freeze-drying systems and processes. The paper presents various rarefied gas dynamics aspects of freeze-drying including thermal creep and conduction, pressure and concentration-gradient driven flows and sonic expansion flows with icing. In particular, flow through the duct where the Knudsen number is small enough is modeled using conventional CFD techniques. The effect of the hardware on flow in the duct is discussed in detail. Furthermore, flow and icing in the freeze-drying condenser is modeled using the direct simulation Monte Carlo (DSMC) technique. The effect of duct length on the uniformity of mass flux and ice accretion rates are discussed. It is found that by increasing the duct length, there is a trade-off between increased residual pressure and improved uniformity. The simulations show that by augmenting the DSMC method with conventional CFD technique in appropriate regimes, the gas dynamics in the entire freeze-dryer system can be modeled numerically for given sublimation rate and geometry.

The Numerical Simulation of the Solar-Air Dual-Source Heat Pump System

The heat pump technology which is as an effective energy-saving technology has attracted more and more attentions. A novel solar-air dual-source heat pump system which could synchronously use two heat sources has been provided. In this paper, the mathematical model of the new heat pump system has been built and the calculation accuracy of the mathematical model has been proved. Based on a novel solar-air dual-source heat pump system, the mathematical models of the thermophysical parameters of working fluids, compressor, capillary, condenser, evaporator, and heat pump system have been established. The distribution parameter method has been adopted in the mathematical models of condenser and evaporator. Three operation modes of the novel solar-air dual-source heat pump system have been simulated. The simulated results and the experimental results have been compared. The experiments of the novel solar-air dual-source heat pump system have been accomplished in the constant temperature and humidity laboratory. The compared results show that the error is less than 10%.

Chillers energy consumption, energy savings and emission analysis in an institutional buildings

Chillers consume more than 40% of the total energy used in the commercial and industrial buildings for space conditioning. In this paper, energy consumption by chillers and chilled water pumps, condenser pumps and fan motors has been estimated using data collected by a walkthrough energy audit for the 16 faculties of the University of Malaya. It has been estimated that chillers and motors and pumps used in chillers consume 10,737 MWh (i.e. 51% of total energy consumption) of electric energy for different percentage of loadings. As chillers are major energy users, variable speed drives are applied in chillers to reduce their energy consumption. It has been estimated that about 8368 MWh annual energy can be saved by using efficient chillers at different loadings. It has also been found that about 23,532 MWh annual energy can be saved for chilled water supply pumps, condenser pumps and cooling tower fan motors by matching required speeds using variable speed drives for 60% of speed reduction. About 1,274,692 kg of CO 2 emission could be avoided for using energy efficient chillers at 50% load. It has been also found that about 2,426,769 kg CO 2 emission can be reduced by using variable speed drives for 60% speed reductions. Payback periods found to be only few months for using variable speed drives in chilled water pumps, condensers and fan motors.

Determination of flow throttling conditions in a system used to transport water from cooling towers to turbine condensers

Water from cooling towers is transported to condensers via a system including screens that are to arrest mechanical impurities and not let them pass into condensate pumps. These screens, when clogged, often cause throttling the water flowing to condensers, hence, interference in power unit operation. Thus, it is of importance to allow for the screen clogging extent monitoring from the power unit control room in order to adapt periodical cleaning frequency to the actual needs. The authors who provided solution to this problem have used an original answer allowing one to observe the system in operation and flow conditions of water stream from cooling towers to condensers and also permitting possible decision taking about cleaning the screens installed in the system [1, 2].

Theoretical analysis of a single-stage and two-stage solar driven flash desalination system based on passive vacuum generation

An innovative solar driven flash desalination system is proposed. The system uses the natural forces of gravity and atmospheric pressure to create a vacuum. Single-stage and two-stage concepts have been outlined. The main components include evaporator(s), condenser(s), collection tanks, heat source and seawater circulation pump. Partial heat recovery is attained by first passing the feedwater through the condenser(s), followed by the heat source. Additional distillate output is obtained in the second stage of the two-stage system without any extra heat addition, since the high temperature brine from the first stage is passed and flashed in the second stage. Theoretical analysis of the single-stage and two-stage concepts is done for the system when coupled with constant temperature heat source and solar collector. When coupled with a solar collector of 1 m 2 area, a single-stage system produces 5.54 kg of water in 7.83 h, while the two-stage system produces 8.66 kg in 7.7 h. The performance ratios obtained, including the efficiency of solar collectors, are 0.48 and 0.75 for a single-stage and two-stage system respectively, or 0.748 and 1.350 if only the useful heat collected by the solar collector is considered.

ENTROPY METHOD AS CRITERIA FOR ANALYSIS A STEAM POWER PLANT

In this paper a theoretical analysis of South Baghdad and Dura power plant is carried out according to second law of thermodynamic depending on entropy (irreversibility coefficient or lost work) method instead of exergy (availability) method. In the used entropy method. The power plant is divided into main blocks ( boiler, turbine, condenser, and feed water heater and pumps ). The irreversibility losses and coefficient for each block are calculated and then the overall irreversibility and thermal efficiency of the plant are calculated. The results of this work are compared with previous results, that depending on exergy method. The comparison of results show that both methods give approximately the same results since both of them rely the 2nd law of thermodynamic. Entropy method is simple and intellectually and intuitively satisfying and giving direct relationship between components losses of power plant and its overall efficiency.

Spin pump for boosting spin polarization of superfluidHe3A1phase

Mechanical pumping and filtering of spin-polarized condensate were realized in the superfluid $^{3}\text{He}$ ${\text{A}}_{1}$ phase by the pneumatic pumping action of an electrostatically actuated diaphragm. Spin pumping increased the net spin polarization by $20--50\text{ }%$ as measured by the induced pressure change during spin pumping. The observed spin relaxation time was consistent with the increased spin polarization. These observations demonstrate the feasibility of using spin pumping to substantially increase the effective magnetic field to which the ${\text{A}}_{1}$ phase is exposed.