Addressing Fouling by Qualifying Chemical Additives Using Novel Technologies

2021 ◽  
Author(s):  
Andrew Robert Farrell ◽  
Dario Marcello Frigo ◽  
Gordon Michael Graham ◽  
Robert Stalker ◽  
Ernesto Ivan Diestre Redondo ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Emulsion Stability ◽  
Ambient Pressure ◽  
Screening Tests ◽  
Process Conditions ◽  
Screening Methods ◽  
Chemical Additives ◽  
Laboratory Techniques ◽  
Prediction And Prevention

Abstract Fouling of heat exchangers and production of stable emulsions in desalting units can present significant challenges in refinery operations. Often these difficulties occur due to the concurrent processing of two or more crude oils that are incompatible under process conditions. This paper describes a significant development in laboratory techniques for studying these issues and evaluating mitigation strategies. Asphaltenes compatibility was evaluated for oil mixtures that may be co-processed in the refinery using a deposition flow rig, and the results were compared with those obtained with more conventional tests: blending stability analysis by light scattering and various screening methods. The flow rig mimics the process conditions (elevated pressure, high temperature, flow-induced shear) and identifies whether deposition or precipitation will occur. The former can cause fouling of heat exchangers whereas the latter produces solids that can stabilize emulsions in the desalter. By varying the proportions of oils that were co-injected into the deposition flow rig, the range within which mixtures were unstable was found. By flowing through a capillary (to mimic a heat exchanger) and in-line filter, it was possible to identify whether precipitation of suspended flocs or fouling of the heat exchanger itself was the likely issue for each mixture. Emulsion-stability tests were conducted using a pressurized rig with an ersatz separator to mimic the desalting unit; results were compared with those obtained in conventional, ambient-pressure bottle tests. Oil(s) and refinery wash water were injected, mixed under representative shear, and allowed to separate within the typical residence time of the desalter. Chemical additives were tested to identify those that were effective at controlling any observed problems. Results obtained in either flow rig (using representative pressure, temperature, and shear) did not always match those obtained using conventional methods. Asphaltenes fouling occurred under conditions where it was not predicted by screening tests that were conducted at conditions not representative of the process and did not occur under conditions where it was predicted. Differences were also observed between the emulsion stability observed in bottle versus rig tests, though these should be viewed as complementary techniques. This paper presents new laboratory techniques for the prediction and prevention of refinery fouling and emulsion stability. They mimic conditions in the facilities much better than those typically used to date.

Analysis of Large Dry Cooling Towers With Power-Law Heat Exchanger Performance

1976 ◽  
Vol 98 (3) ◽  
pp. 345-352 ◽  
Author(s):  
F. K. Moore ◽  
C. C. Ndubizu
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Ambient Pressure ◽  
Tube Length ◽  
Cooling Towers ◽  
Tube Size ◽  
Best Value ◽  
A Chain ◽  
The Cost ◽  
Dry Cooling

An analysis is presented for heat exchanger area, tower exit area, and exchanger tube length and number, for heat exchangers in large dry cooling towers, having performance parameters given by powers of Reynolds number, but otherwise under very general cooling-cycle constraints. The calculation method is illustrated for a “spine-fin” heat exchanger which, in a tube size of about 3/8 in., seems capable of achieving low tower size in a practical device. Calculations, over ranges of water pumping power, approach, ITD, number of passes, tube size, tower shape (natural draft) or fan power (mechanical draft), and ambient pressure altitude are shown to be well represented by a chain of powers of these variables, and certain functions of the ratio of real to ideal tower exit area. This ratio is shown to have a best value, depending on the cost coefficients of heat exchange and exit areas, and it is pointed out that typical cost proportions lead to a fluid-mechanical “packaging” problem for the shallow heat exchangers which would be preferred.

Analysis and Design of the “Solar One” Thermal Storage Subsystem Heat Exchangers

1984 ◽  
Vol 106 (3) ◽  
pp. 279-285
Author(s):  
F. R. Weiner
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Thermal Storage ◽  
Design Solution ◽  
Process Conditions ◽  
Analysis And Design ◽  
Heat Exchanger Design ◽  
Central Receiver ◽  
Final Design ◽  
Design Requirements

This paper describes the analysis and design of the five kinds of heat exchangers used in the thermal storage subsystem of the 10 MWe Solar Central Receiver Pilot Plant, now becoming more known as “Solar One.” The paper discusses the practices and standards used in the designs of the heat exchangers, lists the heat exchanger design requirements, and discusses the process conditions. The design assumptions and constraints, the geometrical considerations, and the tradeoff studies that were conducted to optimize the designs are also discussed. A description of each heat exchanger reveals the final design solution. Novel and unique features of a power plant that must operate on a daily sun-cycle are identified.

scholarly journals Heat Transfer Characteristics of Heat Exchangers for Waste Heat Recovery from a Billet Casting Process

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2695
Author(s):  
Ju O Kang ◽  
Sung Chul Kim
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Waste Heat ◽  
Casting Process ◽  
Effective Area ◽  
Total Heat ◽  
Process Conditions ◽  
Heat Absorption ◽  
Industrial Facilities ◽  
The Difference

The application of the thermoelectric generator (TEG) system to various industrial facilities has been explored to reduce greenhouse gas emissions and improve the efficiency of such industrial facilities. In this study, numerical analysis was conducted according to the types and geometry of heat exchangers and manufacture process conditions to recover waste heat from a billet casting process using the TEG system. The total heat absorption increased by up to 10.0% depending on the geometry of the heat exchanger. Under natural convection conditions, the total heat absorption increased by up to 45.5%. As the minimum temperature increased, the effective area increased by five times. When a copper heat exchanger of direct conduction type was used, the difference between the maximum and minimum temperatures was significantly reduced compared to when a stainless steel heat exchanger was used. This confirmed that the copper heat exchanger is more favorable for securing a uniform heat exchanger temperature. A prototype TEG system, including a thermosyphon heat exchanger, was installed and a maximum power of 8.0 W and power density of 740 W/m2 was achieved at a hot side temperature of 130 °C. The results suggest the possibility of recovering waste heat from billet casting processes.

Successful Sealing of Heat Exchangers Due to the Implementation of New Technology in a Gasket System

2005 ◽  
Author(s):  
Julie L. Simonton ◽  
David W. Reeves
Keyword(s):  
Thermal Expansion ◽  
Heat Exchanger ◽  
Test Data ◽  
Heat Exchangers ◽  
New Technology ◽  
Process Conditions ◽  
Successful Implementation ◽  
Differential Thermal Expansion ◽  
Effective Seal ◽  
Subsequent Failure

Research into the historical use and subsequent failure of double-jacketed type gaskets in heat exchangers has yielded the characteristics necessary for leak elimination and the realization that maintaining a seal cannot be achieved by gasket specification alone. An evaluation of the heat exchanger, stud load, tightening method, gasket specification, proper installation procedures, process conditions, as well as stud selection must each be carefully considered to consistently create an effective seal. This paper highlights field test data from a refinery on the differential thermal expansion of flanges and how the gasketed connection is affected. Laboratory test data, specifically Radial Shear Tightness Test, or Ra.S.T., data, which mimics the radial shearing effects on a gasket in a heat exchanger, as well as verifying the effects on the gaskets in the field, is also presented. The details of the new technology in a gasket system for heat exchangers, perfected in conjunction with Chevron and Lamons Gasket Company, will be presented along with its successful implementation at a major petrochemical refinery.

Impact of Generator Rating Increase, Ambient Pressure and Coolant Composition and Temperature on Power Generator Heat Exchangers

2010 ◽  
Author(s):  
Luis P. Zea
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Output Power ◽  
Heat Exchangers ◽  
Ambient Pressure ◽  
Operating Conditions ◽  
Total Output ◽  
Inlet Temperature ◽  
Total Output Power ◽  
Transfer Rates

Heat exchangers’ operating requirements vary depending on several parameters such as plant location, coolant input conditions and generator total output power. Some of these parameters play a more important role than others and understanding these roles is key to designing heat exchangers that will better suit their operating conditions. This paper analytically examines the implications that varying four parameters have on a heat exchanger with a fixed geometry and heat transfer area. Ambient pressure decrease translates into changes on the thermodynamic conditions of the gas flow. Coolant composition variances (from condensate to increased glycol percentages) also play an important role on the exchanger’s heat transfer rates, the higher the glycol percentage the lower the heat transfer rate. In the same manner, the coolant inlet temperature will partly determine heat transfer rates. Lastly, a generator total output power increase will yield higher heat losses on several points of the generator and thus, a higher heat load for the heat exchanger. The graphs and data hereby presented should be of assistance to those designing new coolers as well as those operating current ones.

Tube Rupture Study of a 300 Bar Heat Exchanger

2014 ◽  
Author(s):  
Bas Megens
Keyword(s):  
Acoustic Emission ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Failure Mechanisms ◽  
Process Conditions ◽  
Safety Study ◽  
Entire Study ◽  
Root Cause ◽  
Potential Failure ◽  
Non Destructive

From a safety study a concern was raised about the probability of instant tube rupture in 300 bar heat exchangers in LDPE plants. A study has been performed in a multidisciplinary team to determine the potential failure mechanisms. Among the possible potential failure mechanisms those which can cause instant tube rupture were identified. Based on these potential failure mechanisms, non-destructive examinations were performed to investigate if these failure mechanisms were present and online acoustic emission measurements were performed to investigate during which process conditions the damage occurred. Eventually a cooler was dismantled to investigate the root cause of the damage. This paper describes the entire study.

Rapid Screening Methods for Bleeding Disorders. A Three Year Survey

1964 ◽  
Vol 11 (02) ◽  
pp. 506-512 ◽  
Author(s):  
V. A Lovric ◽  
J Margolis
Keyword(s):  
Laboratory Tests ◽  
Capillary Blood ◽  
Screening Tests ◽  
Rapid Screening ◽  
Screening Methods ◽  
Bleeding Disorders ◽  
Routine Laboratory ◽  
Clotting Time ◽  
Kaolin Clotting Time ◽  
In Infants And Children

SummaryAn adaptation of “kaolin clotting time” and prothrombin time for use on haemolysed capillary blood provided simple and sensitive screening tests suitable for use in infants and children. A survey of three year’s experience shows that these are reliable routine laboratory tests for detection of latent coagulation disorders.

Optimization and Standardization of Flanged and Flued Expansion Joint Design

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Kamlesh M. Chikhaliya ◽  
Bhaveshkumar P. Patel
Keyword(s):  
Heat Exchanger ◽  
Optimum Design ◽  
Design Methodology ◽  
Thick Wall ◽  
Process Conditions ◽  
Expansion Joint ◽  
Standard Requirement ◽  
Spring Rate ◽  
Tube Heat Exchanger ◽  
Heat Exchanger Design

Flanged and flued type expansion joint (thick wall expansion bellow) used as an integral part of many shell and tube heat exchanger where process conditions produce differential expansion between shell and tubes. It provides flexibility for thermal expansion and also functions as a pressure retaining part. Design of expansion joints is usually based on trial and error method in which initial geometry must be assumed, and accordingly maximum stresses and spring rate are be calculated. Inadequate selection of geometry leads to higher tubesheet and bellow thickness, which increases cost of equipment. This paper presents standardization and optimum design approach of flange and flued expansion bellow fulfilling ASME VIII-1 and TEMA standard requirement. Methodology to define expansion bellow geometry is developed, and geometry dimensions are tabulated for expansion bellow diameter from 300 to 2000 mm and thickness from 6 to 30 mm. Each defined geometry is analyzed using finite element method, and maximum von Mises stresses are calculated for bellow axial displacement from 0.5 to 1.5 mm and internal pressure from 0.1 to 6.5 MPa. Spring rate is also calculated for each defined geometry for consideration in tubesheet calculation. Accordingly, optimum design methodology is developed, tested, and compared with existing design. Results depicted that proposed standardization approach and design methodology will optimize expansion bellow and tubesheet thickness and will also save considerable time in finalization of heat exchanger design.

Analysis of the Thermal Stress at the Tubesheet in Floating-Head or U-Tube Heat Exchangers

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Jiuyi Liu ◽  
Caifu Qian ◽  
Huifang Li
Keyword(s):  
Thermal Stress ◽  
Heat Exchanger ◽  
Temperature Difference ◽  
Heat Exchangers ◽  
Influence Factors ◽  
Area Ratio ◽  
Shell Side ◽  
Tube Heat Exchanger ◽  
Numerical Tests ◽  
Hole Area

Thermal stress is an important factor influencing the strength of a heat exchanger tubesheet. Some studies have indicated that, even in floating-head or U-tube heat exchangers, the thermal stress at the tubesheet is significant in magnitude. For exploring the value, distribution, and the influence factors of the thermal stress at the tubesheet of these kind heat exchangers, a tubesheet and triangle arranged tubes with the tube diameter of 25 mm were numerically analyzed. Specifically, the thermal stress at the tubesheet center is concentrated and analyzed with changing different parameters of the tubesheet, such as the temperature difference between tube-side and shell-side fluids, tubesheet diameter, thickness, and the tube-hole area ratio. It is found that the thermal stress of the tubesheet of floating-head or U-tube heat exchanger was comparable in magnitude with that produced by pressures, and the distribution of the thermal stress depends on the tube-hole area and the temperature inside the tubes. The thermal stress at the center of the tubesheet surface is high when tube-hole area ratio is very low. And with increasing the tube-hole area ratio, the stress first decreases rapidly and then increases linearly. A formula was numerically fitted for calculating the thermal stress at the tubesheet surface center which may be useful for the strength design of the tubesheet of floating-head or U-tube heat exchangers when considering the thermal stress. Numerical tests show that the fitted formula can meet the accuracy requirements for engineering applications.

Application of Equipartition of Entransy Loss Principle in Heat Exchangers

2012 ◽  
Vol 629 ◽  
pp. 699-703
Author(s):  
Chun Sheng Guo ◽  
Wen Jing Du ◽  
Lin Cheng
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Optimization Design ◽  
Loss Rate ◽  
Plate Heat Exchanger ◽  
Loss Minimization ◽  
Plate Heat ◽  
Entransy Loss ◽  
Heat Exchanges ◽  
Minimization Approach

The entransy loss minimization approach for the heat exchanger optimization design was established by Guo Z Y; the study based Guo Z Y’s works, found relationship between the entransy loss uniformity and the heat exchanger performance and the expression of the local entransy loss rate for heat convection was derived, numerical results of the heat transfer in a chevron plate heat exchanger and helix baffle heat exchanger show that the larger entransy loss uniformity factor appear in about Re=2000 and the entransy loss uniformity factor of chevron plate heat exchanges higher than helix baffle one.

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