Aqueous acid-aided corrosion products removal from the surface of the brass elements of heat exchangers

2019 ◽  
pp. 110-115
Author(s):  
L. M. Mironovich ◽  
A. Yu. Eliseev ◽  
A. Yu. Eliseeva
Keyword(s):  
Heat Exchangers ◽  
Solution Temperature ◽  
Cleaning Process ◽  
Complex Effect ◽  
Aqueous Acid ◽  
Surface Configuration ◽  
Additional Input ◽  
Heat Exchange Equipment ◽  
Working Solution ◽  
Strong Acids

The paper studies complex effect of various factors on the process of cleaning brass brand L-68, used for the manufacture of heat exchange equipment. It has been established that acids of various strengths can be used as working solutions. The speed of the cleaning process depends on the nature of the acid and its initial concentration. For strong acids, a working solution with low concentration is recommended, followed by an increase in their concentration during the cleaning process. Additional input of oxygen into the system and an increase of the working solution temperature increase the cleaning rate of brass. The cleaning process proceeds without significant changes in the surface configuration, and, consequently, the expenditure of metal.

scholarly journals POLYMERS AND PLASTIC USE FOR THE HEAT-EXCHANGE EQUIPMENT (REVIEW)

2020 ◽  
pp. 59-71
Author(s):  
I.O. Mikulionok
Keyword(s):  
Heat Exchange ◽  
Heat Exchangers ◽  
Polymeric Materials ◽  
Strength Properties ◽  
Polymers And Plastics ◽  
Heat Exchange Equipment ◽  
Coefficient Of Heat Conductivity ◽  
Exchange Apparatus ◽  
Polymer Type

The possibility of use of the heat-exchangers in whole or in part manufactured with use of polymers and plastics is considered. Despite obvious, at first sight, inexpediency of use of polymeric materials in the heat-exchange equipment (low coefficient of heat conductivity, and also low, in comparison with metals, the strength properties of the majority of the most widespread polymers), «polymeric» heat-exchangers find application in various areas of the industry more and more surely. Classification of heat-exchange apparatuses which constructive elements are executed with use of polymeric materials is proposed. The following signs are the basis for classification: polymer type, a type of polymer meric material, type of the heat-exchange apparatus (a form of heat-exchange elements), reliance on polymeric materials in apparatuses, motion freedom of polymeric heat-exchange elements, level of assembly of a design, and also diameter of tubular elements. Critical analysis the most characteristic designs developed by domestic and foreign designers and inventors is carried out. Ref. 21, Fig. 13.

Application of Cassette-Tube Airheaters as a Way to Improve the Mass-Size Characteristics of Regenerative Gas-Turbine Units

1999 ◽  
Author(s):  
A. V. Soudarev ◽  
B. V. Soudarev ◽  
V. B. Soudarev ◽  
A. A. Kondratiev ◽  
P. Avran
Keyword(s):  
Gas Turbine ◽  
Heat Exchangers ◽  
Consumption Rate ◽  
Turbine Plant ◽  
Heat Exchange Equipment ◽  
Mass Size ◽  
Gas Turbine Plant ◽  
Gas Pumping ◽  
Pumping Units ◽  
New Generation

To produce a new generation of gas-pumping units and to upgrade the existing ones, the producer needs to update their heat exchange equipment. The aim of the update is to decrease its mass and sizes and to reduce its manufacturing and assembly costs. Heat-hydraulic calculations and experiments with models of the gas-turbine plant cassette-tube airheaters demonstrated that application of profiled U-tubes of a small hydraulic diameter to manufacture the matrices of such heat exchangers provides a high compactness and low metal consumption rate typical for plate heat exchangers. Simplicaty, reliability, elasticity and maintainability which are typical characteristics of tube heat exchangers are retaned.

scholarly journals Estimation of Shutdown Schedule to Remove Fouling Layers of Heat Exchangers Using Risk-Based Inspection (RBI)

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2177
Author(s):  
Abdelnaser Elwerfalli ◽  
Salih Alsadaie ◽  
Iqbal M. Mujtaba
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Oil And Gas ◽  
Waste Heat ◽  
Complex Phenomenon ◽  
Cleaning Process ◽  
Chemical Substances ◽  
Operation Period ◽  
The Heat Transfer Coefficient ◽  
Gas Plants

Oil and Gas plants consist of a set of heat exchangers, which are used in recovering the waste heat from product streams to preheat the oil. The heat transfer coefficient of exchangers declines considerably during the operation period due to fouling. Fouling in heat exchangers is a complex phenomenon due to the acceleration of many layers of chemical substances across tubes of heat exchangers resulting from chemical reactions and surface roughness. In this paper, the fouling process was determined as a critical failure in the heat exchanger. Failure is an accelerated fouling layer across the heat exchanger tubes, which can be the reason for the clogging of tubes. Hence, a risk assessment was conducted using the Risk-Based Inspection (RBI) approach to estimate the probability of fouling in heat exchangers. The results showed that the RBI approach can be used successfully to predict the suitable time to shut down the plant and conduct the fouling cleaning process.

scholarly journals Computational parametric study on efficiency of low boiling point fluid plants under heat exchange process intensification

2021 ◽  
Vol 289 ◽  
pp. 06003
Author(s):  
Alena Likhaeva ◽  
Sergey Grigoriev ◽  
Evgeniy Trushin ◽  
Marat Dasaev
Keyword(s):  
Heat Exchange ◽  
Parametric Study ◽  
Boiling Point ◽  
Heat Exchangers ◽  
Exchange Process ◽  
Electricity Consumption ◽  
Process Intensification ◽  
Exchange Processes ◽  
Heat Exchange Equipment ◽  
Heat Exchange Process

One of the main challenges for the energy industry is to improve the reliability and efficiency of heat exchange equipment in heating plants. Phase-change heat exchangers with low boiling point fluid (LBPF) are widely used in both conventional and renewable energy. The main objectives of increasing the efficiency of heat exchange equipment are to reduce the weight and dimensions, to increase the amount of heat transferred and to reduce the electricity consumption spent on pumping the heat transfer agent. These objectives are achieved by implementing various methods of heat exchange intensification in heat exchange equipment. A key aspect concerning application of various types of heat exchange intensifiers in heat exchange equipment is evaluation of possibility to increase their design efficiency. The paper presents the results of a computational parametric study of changes in efficiency of some LBPF-based plants when intensifying heat exchange processes by modifying functional surfaces of heat exchangers by laser ablation.

scholarly journals Research possibility of application of non-destructive testing method based on the Barkhausen effect for the control of heat exchange equipment, exposed to im-pulse pressure

2019 ◽  
Vol 114 ◽  
pp. 06011
Author(s):  
V.V. Potapov ◽  
M.V. Lopatin ◽  
L.I. Lopatina ◽  
L.M. Chebotnyagin
Keyword(s):  
Heat Exchange ◽  
Heat Exchangers ◽  
Control Method ◽  
Non Destructive Testing ◽  
Barkhausen Effect ◽  
Destructive Testing ◽  
Testing Method ◽  
Heat Exchange Equipment ◽  
Reliability Of Operation ◽  
Non Destructive

The article deals with the issues of ensuring the reliability of operation and methods for evaluation of connections (tube attachment points in tube sheets) of heat exchangers used in various industries. It is estimated the applicability of the control method based on the Barkhausen effect to check the place of tube fastening in tube sheets. Installations are considered as heat exchangers in which the connection is derive pipe with tube sheets is obtained by using impulsed pressure sources.

scholarly journals Optimization of the technological solutions for recharge and boron control system at the NPP for the project AES-2006

2018 ◽  
Vol 245 ◽  
pp. 07017 ◽  
Author(s):  
Anastasia Ulasen ◽  
Aleksandr Kalyutik ◽  
Anatolii Blagoveshchenskii
Keyword(s):  
Control System ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Primary Circuit ◽  
Capital Costs ◽  
Main Pipelines ◽  
Heat Exchange Equipment ◽  
Under Construction

The article considers the possible ways to optimize the technological solutions of the recharge and boron control system of nuclear power plants under construction within the AES-2006 project. The possibilities for optimization of technological solutions of the system of recharge and boron regulation of the AES-2006 project, which will not affect the reliability and efficiency of its main functions: purge-recharge of the primary circuit and boron regulation, were studied. As a result of the analysis of technological solutions and analytical calculations carried out during the work, it was found that in the system of recharge and boron regulation of the NPP within the project AES-2006 it is possible to perform optimization basing on reduction the metal content of the heat exchange equipment by reducing the surface area of the heat exchangers of the coolant outlet, reducing the power of pumps, as well as reducing the diameter of a number of main pipelines. Implementation of the proposed optimization of technological solutions will allow a more rational arrangement of the system and reduce capital costs for the construction of nuclear power plants as a whole, while not adversely affect the safety of the system and its functions.

A Large Flowrate Electroosmotic Pump With Micron Pores

2001 ◽  
Author(s):  
Shuhuai Yao ◽  
David Huber ◽  
James C. Mikkelsen ◽  
Juan G. Santiago
Keyword(s):  
Heat Exchangers ◽  
Volume Ratio ◽  
Glass Frit ◽  
Applied Potential ◽  
Two Phase ◽  
Electroosmotic Pump ◽  
Working Solution ◽  
Fabrication And Characterization ◽  
Effective Pore Size

Abstract This paper presents a description of the design, fabrication, and characterization of a novel, high flowrate electroosmotic pump designed for microcooling applications. The prototype pumps demonstrated a flowrate of 7 ml/min for 200 V applied potential that is suitable for two-phase heat exchangers with a capacity approaching 100 W. This pump uses electroosimotic flow (EOF) to drive the flow and is compact with no moving parts. The pump structure is produced by chemically treating and further sintering an ultrafine glass frit (filter). The frits we use are porous cylinders 30 mm in diameter and 3 mm (varying from 1.5 to 3 mm) thick and provide the high wetted-surface-to-volume ratio required to generate pressures exceeding 2 arm. Both deionized (DI) water and buffered aqueous solutions have been used as working fluids. Experiments have been conducted to characterize the pump performance and investigate its physical properties such as the structure porosity, tortuosity, effective pore size, finite double layer effects, and the dependence of zeta potential on ionic conductivity of the working solution.

Medium effects on tetraalkylammonium ions in aqueous acid solutions

1976 ◽  
Vol 54 (9) ◽  
pp. 1439-1444 ◽  
Author(s):  
Tomasz A. Modro ◽  
William F. Reynolds ◽  
Keith Yates
Keyword(s):  
Aqueous Solutions ◽  
Chemical Shifts ◽  
Ionic Species ◽  
Acid Solutions ◽  
Medium Effects ◽  
Tetraalkylammonium Ions ◽  
Aqueous Acid ◽  
Low Field ◽  
Cation Hydration ◽  
Strong Acids

Medium effects upon 1H and 13C chemical shifts have been determined for some tetraalkylammonium ions in 0–10 M aqueous solutions of H2SO4, HClO4, and H3PO4. The observed effects are very weak in magnitude, thus justifying the choice of tetraalkylammonium ions as reference standards for studies of ionic species in aqueous solutions of strong acids. The trends in the observed low-field shifts are interpreted in terms of changes in cation hydration and in hydrogen bonding between alkyl hydrogens and acid anions.

Theoretical Analysis of Effects of Solution Heat Exchanger on the Performance of Mixed Absorption Refrigeration Cycle

2012 ◽  
Vol 170-173 ◽  
pp. 2521-2524
Author(s):  
Wen Li ◽  
Jun Hua Wan ◽  
Jing Liu ◽  
Zu Yi Zheng ◽  
Wen Ming Xu
Keyword(s):  
Heat Exchanger ◽  
Theoretical Analysis ◽  
Temperature Difference ◽  
Heat Exchangers ◽  
Water Flow Rate ◽  
Cooling Water ◽  
Solution Temperature ◽  
Refrigeration Cycle ◽  
Absorption Refrigeration ◽  
Cooling Water Flow Rate

The model of solution heat exchangers of mixed absorption refrigeration cycle was developed. The effects of strong solution temperature difference between inlet and outlet of solution heat exchanger on the coefficient of performance (COP) and cooling water flow rate of mixed absorption refrigeration cycle were analyzed, at the same time, the effects of temperature difference on the unit heat exchange area of counter-flow and cross-flow solution heat exchangers were analyzed. The theoretical analysis results showed that there was an optimal value for the strong solution temperature difference, for the mixed absorption system, the optimal temperature difference was about 12°C, the corresponding COP was 11.2% higher and the cooling water flow rate was 7.8% less than that of system without heat exchanger.

Hydrodynamic Effects on Particle Deposition in Microchannel Flows at Elevated Temperatures

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Zhibin Yan ◽  
Xiaoyang Huang ◽  
Chun Yang
Keyword(s):  
Reynolds Number ◽  
Steady Flow ◽  
Deposition Rate ◽  
Pulsatile Flow ◽  
Heat Exchangers ◽  
Particle Deposition ◽  
Elevated Temperatures ◽  
Solution Temperature ◽  
Particulate Fouling ◽  
Hydrodynamic Effects

Particulate fouling and particle deposition at elevated temperature are crucial issues in microchannel heat exchangers. In this work, a microfluidic system was designed to examine the hydrodynamic effects on the deposition of microparticles in a microchannel flow, which simulate particle deposits in microscale heat exchangers. The deposition rates of microparticles were measured in two typical types of flow, a steady flow and a pulsatile flow. Under a given elevated solution temperature and electrolyte concentration of the particle dispersion in the tested flow rate range, the dimensionless particle deposition rate (Sherwood number) was found to decrease with the Reynolds number of the steady flow and reach a plateau for the Reynolds number beyond 0.091. Based on the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, a mass transport model was developed with considering temperature dependence of the particle deposition at elevated temperatures. The modeling results can reasonably capture our experimental observations. Moreover, the experimental results of the pulsatile flow revealed that the particle deposition rate in the microchannel can be mitigated by increasing the frequency of pulsation within a low-frequency region. Our findings are expected to provide a better understanding of thermally driven particulate fouling as well as to provide useful information for design and operation of microchannel heat exchangers.

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