The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. Fouling is a function of the system and the equipment used. Since all heat exchangers considered in this experiment have a single pass for both the hot and cold fluids, the discussion below is limited to singlepass heat exchangers. Expresstm, novel heat exchanger analysis software for heat exchanger fouling in the pre heat train of a crude oil distillation unit. Hi,i usually advise people to use the following equation to monitor fouling factor. In the co2 scrubbing process three plate heat exchangers are switched in parallel, two in operation a and b and one in standby c. Figure 4 shows the three coolers with their operating conditions.
If uncontrolled, levels of fouling can negate any benefits produced by careful heat exchanger design. Mtd mean temperature difference normally, this equation is solved for the surface area or a, since the heat load is known, and the overall heat transfer coefficient and the mtd can be calculated, based on known information. Different types of heat exchangers in addition, the overall heat transfer equation for the exchanger must be solved simultaneously. Parameters which influence the fouling rate in a system include. Heat exchangers consist primarily of bundles of pipes, tubes or plate coils. The thermal resistance and the overall heat transfer coefficients based on the inner and outer areas are to be determined. Heat exchangers can be cleaned, and you have to judge when cleaning is necessary. Pdf fouling of heat exchangers hamza shafiq academia. Analysis of heat exchanger fouling in cane sugar industry. The factor used to correct the log mean temperature. All trademarks, registered trademarks, product names and company names or logos mentioned herein are the property of their respective owners. R sekulib university of kentucky introduction a heat exchanger is a device that is used for transfer of thermal energy enthalpy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a. Heat exchanger fouling calculation posted in process heat transfer.
Heat exchangers are used in both cooling and heating processes. The former may include bacteria, fungi or algae, while the latter includes mussels and barnacles. Shell and tube heat exchanger design is a product developed by webbusterz engineering software. Fouling factor monitoring industrial professionals. The excess surface area is required to compensate for the reduced heat transfer coefficient due to fouling. Bott this unique and comprehensive text considers all aspects of heat exchanger fouling from the basic science of how surfaces become fouled to very practical ways of mitigating the problem and from mathematical modelling of different fouling mechanisms to practical methods of heat exchanger cleaning. Bahx product bulletin 8 what it is and why its bad fouling occurs when compounds in the streams solidify inside the bahx and coat the heat transfer surfaces. Fouling layers with a thickness of 3 mm are indicated in dark grey, and with a thickness of 1 mm in light grey. Fouling of heat exchangers in processing industries is a chronic operating problem. The result is an increased pressure drop in the water circuit of the heat exchanger. Fouling in heat exchangers industrial heat exchangers.
The dirty truth about heat exchanger fouling heatcalc. Heat exchanger and its types engineering solutions. Counter flow heat exchangers are the most efficient of the three types. Heat exchanger fouling and cleaning conference series. Apr 18, 2016 shell and tube heat exchanger fouling factors engineers are often faced with interoffice scheduling traditions. During operation with liquids and gases a dirt film may build up on the heat exchanger surfaces.
Anti fouling coatings based on nanocomposites have been used to decrease fouling inside plate and frame heat exchanger for food production. A third potential problem is corrosion on the water side of the heat exchanger due to poor water quality control. Understanding and preventing heat exchanger fouling. Heat exchangers 73 individual thermal resistances of the system. Due to different designs, composition, and transfer fluid, each type of heat exchanger will suffer fouling in unique ways. Examples of components that may be subject to fouling and the corresponding effects of fouling. The fouling factor number one is the character of the liquid itself. The thermal resistance due to fouling accumulated on the heat transfer surface. The fouling factor represents the theoretical resistance to heat flow due to a build. Tm is the log mean temperature difference given as t t. The fouling factors to be used in the design of heat exchangers are normally specified by the client based on their experience of running the plant or process.
Autoassociative kernel regression aakr modeling was applied to predict the effect of fouling on the heat transfer resistance. To operations, fouling is a creeping buildup that gradually reduces heat exchanger performance. Uniform velocities and near plug flow conditions achieved in a helixchanger heat exchanger, provide low fouling characteristics, offering longer heat exchanger run. Fouling of heat exchangers free download as powerpoint presentation. However, fouling is a selffulfilling prophecy and the selection of fouling factors or excess area must be done carefully. Combining each of these resistances in series gives. Extensive technical literature is available on heat exchanger design, operation and maintenance, but it is widely.
For shell and tube heat exchanger, the common method is to use fouling factors. Two examples of this are adiabatic wheels, which consist of a large wheel with fine threads rotating through the hot and cold fluids, and fluid heat exchangers. For other types of heat exchangers, excess heat transfer area is often used. First, if the particles are large 1 mm or have a fibrous structure, they may lodge in the inlet of the heat exchanger or clog the channels. Specific heat capacity of air at constant pressure. Wilson department of chemical engineering, pembroke street, cambridge cb2 3ra, uk email. Plate heat exchanger 2 operation and maintenance manual. Over 90% of all heat exchangers suffer from fouling. Heat exchanger gtl heat exchanger for systems with gas and thermal liquid flows. A heat exchanger is a device that is used to transfer thermal energy enthalpy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures and in thermal contact.
While this may help the heat transfer, the small gaps between fins are magnets for fouling. Increased thermal resistance caused by the deposit can normally only be obtained from tests or experience. In fact, fouling has been recognised for a long time, and research on heat exchanger fouling was conducted as early as 1910 and the first practical application of this research was implemented in the 1920s. Fouling represents additional resistance to heat transfer and causes the rate of heat transfer in a heat exchanger to decrease, and the pressure drop to increase. The tube side of a shell and tube heat exchanger is usually easy to clean but the shell side can be more difficult to access. This means that more energy is required to get the desired flow through the heat exchanger. I already calculated current u value with current operating conditions and i have design u value of exchangers from the spec. Shell and tube heat exchangers page 6 of 30 mnl 032a issued 29 august 08, prepared by j. He found out that fouling agents can contain inorganic materials such as airborne dust and grit, waterborne mud and silt, as well as organic materials including biological substances and elemental carbon.
Fouling of a specific heat exchanger is, besides from the fouling agent. The development of fouling depends on a number of things, 5 and 16. In fact, fouling has been recognised for a long time, and research on heat exchanger fouling was conducted as early as 1910 and the first practical application of this research was. Smooth tube over finned tube many heat exchangers will use fins to increase the heat exchanger area. A fourth type of heat exchanger uses an intermediate fluid or solid store to hold heat, which is then moved to the other side of the heat exchanger to be released. Heat exchanger fouling calculation process heat transfer. Fouling of heat transfer surface affects both capital and operating costs of heat exchangers.
Fouling has a significant impact on heat transfer across the heat exchanger surface, and therefore on the overall operational performance and the economics of the process. The factors such as alkalinity, hardness, ph value. Corrosion fouling is fouling deposit formation as a result of the corrosion of the substrate. Shell and tube heat exchangers page 4 of 30 mnl 032a issued 29 august 08, prepared by j. Fouling mitigation using helixchanger heat exchangers. Manuals for the hisaka plate heat exchanger consist of the following seven related documents. Heat exchanger fouling and estimation of remaining useful life tutpol ardsomang1, j.
Costs due to overdesign, additional fuel consumption and maintenance, loss of production, etc. Fouling factor and calculation results files are generated. Depending on the specific design and orientation, these fins may be difficult or impossible to clean even with a. Heat exchangers have widespread industrial and domestic applications. E1mnl032a design and rating of shell and tube heat.
A heat transfer device used to exchange heat between two liquid streams that are single phase fluids. Awad 2011 studied the fouling of heat transfer surfaces in general. Chunangad2 and venkateswaran pushpanathan3 1 abb lummus heat transfer, 1515 broad street, bloomfield, nj 07003, usa. The techniques of on and offline cleaning of heat exchangers to restore. Heat exchanger for systems with fluids susceptible to phase change. Crystallization fouling often referred to in water systems as scaling, involves the formation of crystals form solution on the surface or deposition of crystals formed in the bulk liquid or in the laminar sublayer particulate fouling, as the name suggests, depends on the arrival of discrete particles at the transfer surface. Heat exchanger fouling of course reduces the opportunity for heat recovery with its. It has extensive domestic and industrial applications. Biological fouling may be defined as the growth of living matter on heat exchanger surfaces.
The liquid stream with the higher inlet temperature. R d fouling factor or unit thermal resistance of deposit m 2 kw u d overall heat transfer coefficient of heat exchanger after fouling wm 2 k u overall heat transfer coefficient of clean heat exchanger wm 2 k 1 can also be expressed as. In fact, fouling has been recognised for a in fact, fouling has been recognised for a long time, and research on heat exchanger fo uling was. The fouling factor represents the theoretical resistance to heat. Heat exchanger surfaces reduces thermal efficiency, decreases heat flux, increases temperature on the hot side, decreases temperature on the cold side, induces underdeposit corrosion, increases use of cooling water. Heat exchanger gg heat exchanger for systems with two gas flows. U overall heat transfer coefficient, btuhrsq ft of a surface area, sq ft. Fouling and reduced heat transfer in heat exchangers.
I am developing heat exchanger monitoring spreadsheet. Alfa laval offers two different types of transfer line exchang. After the presentation of the experimental setup, a brief. Results of fouling factors validation and writing back validated calculated data into the plant information system. As its name implies, this type of heat exchanger consists of a shell a large vessel. Qualitative dependence of the fluid temperature on position inside a singlepass heat exchanger is shown in fig. The primary detriment of fouling is reduced heat transfer, however severe fouling can lead to obstruction and plugging of the passages. F12 improved use of fouling allowances in heat exchanger design 2002 q61 fouling of middle distillate blends 2002 f analysis of htri crude oil fouling data 2003. The buildup of fouling also reduces the crosssectional area of the tubes or flow channels and increases the resistance of the fluid passing over the surface. The convection heat transfer coefficient is 25 wm 2 k on the glycerin shell side and 160 wm 2 k on the water tube side. Completely revised and updated to reflect current advances in heat exchanger technology, heat exchanger design handbook, second edition includes enhanced figures and thermal effectiveness charts, tables, new chapter. Completely revised and updated to reflect current advances in heat exchanger technology, heat exchanger design handbook, second edition includes enhanced figures and thermal effectiveness charts, tables, new chapter, and additional topicsall while keeping the qualities that made the first edition a centerpiece of information for practicing engineers, research, engineers, academicians.
The phenomenon usually associated with water systems, e. This section introduces the basic mechanisms of heat excahnger fouling, hx physical model, aakr and gpm with bayesian updating. Fouling on the heat exchanger surfaces is a major problem in waste heat recovery equipment which can lead to significant efficiency deterioration. Fired heaters the selection of a heat exchanger depends on many factors including capital and operating costs, fouling, corrosion tendency, pressure drop, temperature ranges, and safety issues tolerance to leakage. This site is not directly affiliated with webbusterz engineering software. Download pdf heat exchanger design handbook second edition. The fouling resistances inside the phe are much lower than that inside the shell and tube heat exchanger.
The design, installation, commissioning and operation of heat exchangers to minimise fouling. Bott fouling of heat exchangers chemical engineering. Paul watkinson, engineering conferences international, tomar, portugal, july 1 6, 2007 produced by the berkeley electronic press, 2016. Variation of fouling factor in exchanger d in 2001. The lowenergysurfaces led to a hydrophobic and oleo. Fouling factor monitoring posted in industrial professionals. So then, how can i calculate fouling to see if the heat exchanger is going to be plugged or not. The flow of water influences both scaling and corrosiveness in heat exchanger tubes. The actual fouling rate is different for each application. Plate heat exchanger hereinafter phe performs heat exchanging by transferring heat between hot and cold fluids flowing alternately through heat transfer plates, which are thin metal sheets having fine corrugated patterns. Analysis of heat exchanger fouling in cane sugar industry citation for published version apa. In contrast to the parallel flow heat exchanger, the counter flow heat exchanger can have the hottest coldfluid temperature greater than the coldest hotfluid temperatue. Particulate fouling can influence the performance of the heat exchanger in two ways, depending on the particle size. Antifouling he new technology can reduce heat exchanger.
The formation of fouling on the heat transfer surfaces instantly leads to a reduction of the free space between the plates. Actual fouling factor calculations for each heat exchanger, using the methodology explained bellow. While we were working with a local engineer on a heat exchanger application, she asked why the office always specified a. Furthermore, the type of heat exchanger, if it is a plate or shellandtube heat exchanger. Heat exchanger fouling and estimation of remaining useful life. For a new heat exchanger the fouling factor is zero and it increases with time with increased fouling. This heat exchanger tutorial is a guided exercise in creating a templatized heat exchanger including a downtime tracking event frame. It was developed over a period of more than five years in close collaboration with the oil industry fouling working party, a team of oil refiners, heat transfer equipment manufacturers and chemical suppliers. While some improvements in fouling and cleaning were observed for some of the coatings, there is only, to the authors knowledge, the alfa. Fouling depends on the type of heat exchanger, and the kind of fluids being transferred. Too little cleaning, and your heat exchanger performance degrades unacceptably.
It is equivalent to calculate the individual film heat transfer coefficients for each side of the heat exchanger. Proceedings of 7th international conference on heat exchanger fouling and cleaning challenges and opportunities, editors hans mullersteinhagen, m. Fouling mitigation using helixchanger heat exchangers bashir i. Assumptions 1 the heat transfer coefficients and the fouling factors are constant and uniform. It is clear that the fouling of the surfaces is undesirable. Often, for recovering energy from an industrial exhaust, a dimpletype heat exchanger would be used. Calculate the required heat transfer rate, q, in btuhr from specified information about fluid flow rates and temperatures. This means that impurities dissolved or suspended in the fluid will form incrustations on the heat transfer surfaces. Shell and tube heat exchanger design free download for. Proven dramatic results show it can help companies save thousands of hours of cleaning and millions of dollars in costs every year.
A heat exchanger is a device that is used to transfer thermal energy enthalpy between two or more fluids, between a solid surface and a fluid. You will practice using formula, table lookup and pi point data references to calculate the heat transfer coefficient of the heat exchanger. Fouling factors for heat exchanger design smart process. Its effect on the heat transfer coefficient is accounted for by introducing a thermal resistance. Pdf the paper describes the mechanisms in the development of biofouling layers initial surface conditioning, microbial transport and. Monitoring thermal efficiency of fouled heat exchangers 457 therefore, the value of ntu for one exchanger in the network can be obtained by replacing e by e in the expression developed for a 1 n exchanger eq. Fundamentals of heat exchanger design download ebook pdf. Fouling factors in heat exchangers resources hrs heat. Heat exchanger g heat exchanger for systems with gas and controlled flows. The clean outlet temperature s are calculated and the u c is reported.
Determine the rate of heat transfer in the heat exchanger a before any fouling occurs and b after fouling with a fouling factor of 0. Fouling tendencies depends on the type of heat exchanger and the. A sthe is the most common type of heat exchanger in oil re fineries and other large chemical processes, and is suited for higherpressure applications. Fouling and its effect on the thermal performance of heat exchanger. In a helixchanger heat exchanger, the quadrant shaped shellside baffle plates are arranged at an angle to the tube axis creating a helical flow pattern on the shellside. A heat exchanger is a system used to transfer heat between two or more fluids. These problems can cause severe failures, and in the worst case production loss. Make an initial estimate of the overall heat transfer coefficient, u, based on. Fouling of heat exchangers heat exchanger heat transfer. Heat exchanger is equipment used to transfer heat from one fluid to another.
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