JP2006524311A - Method for improving flow and reducing fouling in process equipment - Google Patents

Abstract

The present invention relates to a method and apparatus for increasing flow rate and reducing fouling in process equipment, such as a heat exchanger (2), where the fluid flows in a single phase or mixed phase. This is obtained by applying a dc potential to the wall of the process equipment so that the dc potential is exactly the reverse of the naturally occurring potential due to the interaction between the process equipment wall and the fluid flow interior. . By improving the flow rate, the heat exchanger (2) becomes more efficient, that is, the adhesion rate is lowered and the inorganic agent removal rate is increased. The fluid may be a pure fluid, a colloidal fluid, or may contain inclusions on the particles.

Description

  The present invention relates to a method and a process device for improving flow rate and reducing fouling in a process device in which a fluid such as a heat exchanger flows in a single phase and a mixed phase. The improved flow rate makes the heat exchanger more efficient, i.e., the deposition rate is lower and the inorganic agent removal rate is higher. The fluid may be a pure fluid, a colloidal fluid, or may contain a particulate mixture.

  The formation of deposits (dirt) on the surface of the heat exchanger is a major cost factor when installing and operating the heat exchanger. As a result of deposits on the surface of the heat exchanger, the heat transfer rate often decreases. It may also cause other driving problems. Heat exchangers are used in almost every type of industry, including the process industry and the petroleum industry. Thus, the fouling problem exists in almost every kind of industry. The total cost of fouling in the industrial world is estimated to be about US $ 40 billion annually [1].

  Despite the huge costs associated with fouling; only very limited research has been conducted on this issue. Reliable knowledge of the economic aspects of fouling is important in assessing the cost effectiveness of various mitigation strategies. Despite a wealth of practical experience in fouling prevention methods and results from ongoing research, the fouling problem in heat exchangers is still a major problem. Therefore, there is a great need to develop new and more effective methods for reducing and preventing the degree of fouling in heat exchangers.

  A number of known chemical and physical / mechanical methods exist to reduce / eliminate scaling and / or fouling problems in systems through which water and / or other process fluids flow. However, the efficiency of such methods varies greatly from method to method and has some disadvantages.

  One way to deal with scaling and / or fouling problems in heat exchangers in one widely used method is to add one or more drugs, called so-called chemical methods, to the liquid in the system. Thus, there is a way to increase the solubility of the mixture forming scaling and / or fouling. These methods are known to be effective both in preventing scaling / fouling formation and in dissolving already formed scaling / fouling. In the case of heat exchangers, the method of adding the drug to the process fluid, which often reduces product quality, or the method of adding the drug to the cooling / heat transfer medium, which may cause contamination problems Either method is common. These problems can be solved by periodically performing a cleaning procedure, which involves removing the heat exchanger from the process line and flushing with the cleaning liquid. However, in this case, it is necessary to stop the operation of the normal process clearly, and the operation cost increases accordingly. As a result, chemical processing is often considered expensive and labor intensive to be a safe solution to the scaling / fouling problem.

Therefore, the focus is on prevention, and in some cases, the scale-forming effect is extinguished by applying an electric and / or magnetic field to the flowing water and / or process liquid. For this effect to occur, the electromagnetic field is exposed to a water / liquid stream to produce nuclei clusters that become seed crystals in the bulk liquid, thereby precipitating the mixture forming scale / and / or fouling, It is common to make suspended particles agglomerated in bulk liquid and then carry away with the bulk stream. An example of such a technique is disclosed in EP 0720588 (EP 0720588), where water is subjected to a high frequency signal to prevent scale formation. It has also been reported that magnetic fields can help prevent lime scaling in much the same way as electric fields. An example of such a technique is disclosed in US Pat. No. 4,278,549. In WO 94/02422 (WO 94/02422), a water stream is exposed to microwave radiation and the frequency of the radiation is determined by the following water ions / compounds: Ca ²⁺ , CO ₃ ²⁻ , HCO ₃ ⁻ , CO _2. , Devices and methods for adjusting to be absorbed by one or more of CaHCO ₃ ⁺ , H ₂ CO ₃ , and H ₂ O. This method is believed to be a method in which the precipitate is not formed on the surface of the process equipment by electromagnetic radiation but on a small scale in the bulk stream to be removed.

The effects of such electromagnetic treatment methods when scaling or precipitating CaCO ₃ accumulates are well discussed by the American Petroleum Institute [2] and scientists [3-10]. The results from various experiments and tests are debatable. Some results indicate that the precipitation of calcium carbonate is reduced by a magnetic and / or electric field, but some are not. However, the method of introducing the magnetic / electric field and the amplitude of the magnetic / electric field vary from experiment to experiment. Therefore, the parameters describing the exposure system will also vary from experiment to experiment. In addition, no quantitative correlation has been reported between the parameters describing the magnetic / electric field and the effect on the fluid flow system. Therefore, due to this lack of scientific knowledge, it is almost impossible to completely control the effects of these methods on calcium carbonate deposition.

  However, theoretical and experimental studies have been conducted to understand the fouling mechanism and to reduce the degree of fouling in heat exchangers. Mechanisms include fouling by crystallization, fouling by microparticles, fouling by organisms, fouling by chemical reaction, fouling by corrosion, and fouling by freezing. However, although it is unlikely that fouling will be due to a single mechanism alone, in many situations one mechanism will dominate. The results of studies on the various mechanisms involved in the fouling process indicate that the following three parameters are more important than other parameters for controlling the fouling process: temperature gradient across the heat exchanger surface, fouling And the flow rate at the heat exchanger surface [11, 12]. The effect on the flow rate is exploited in the present invention.

  The main objective of the present invention is to provide a method and apparatus for increasing / facilitating the flow rate in process equipment, in which process liquid is flowing to reduce / eliminate fouling problems.

  Another object of the present invention is to provide a method and apparatus for improving / facilitating the flow velocity at the heat transfer surface in a heat exchanger, thereby increasing the efficiency of the heat exchanger and at the same time reducing fouling problems / Exclude.

  The objects of the invention are achieved by the methods and apparatus defined in the appended claims and / or the following description of the invention.

The present invention is based in part on the effects discovered by the inventor, which are the basis of another invention protected by, for example, US Pat. No. 6,334,957 or the corresponding European Patent No. 1021376 (EP1021376). It has become. This patent family fully describes the effect and is therefore included as a reference in this application. Here is an outline of the effect only:
-When the fluid flows in the pipe, there will be a free charge on the pipe wall which is separated by shear forces in the boundary layer. As a result, a potential (electric friction potential) is generated at the pipe wall. In the pipe wall, charged particles, ions and dipoles in the fluid are attracted and held, and as a result, a frictional force is generated, which lowers the liquid flow velocity in the pipe. For these reasons, fluid friction is often regarded as an electrical contribution to the friction factor.

  The invention disclosed in U.S. Pat. No. 6,334,957, by applying such a DC potential to the pipe / duct wall to accurately cancel the charge accumulated at the wall, by applying such a DC potential to the pipe / duct wall. It is based on being able to prevent. Therefore, the electromagnetic force attracting ions and polar molecules is reduced, and the fluid in which ions and polar molecules flow may be freely followed. In other words, the electrical contribution to the friction factor is zero and the average fluid flow velocity is consequently increased, especially at the liquid-solid boundary (at the wall). U.S. Pat. No. 6,334,957 discloses a method for ensuring that the applied DC potential is always exactly opposite to the electrical friction potential and a device for carrying out the method.

  The present invention has also been formed in some cases to eliminate electrical friction factors related to liquids flowing in pipes, heat exchangers, nuclear reactors and any other form of industrial process equipment, to prevent fouling and scaling. It is based on the discovery that it is a convenient and effective means of restoring fouling and scaling. That is, by increasing the flow velocity at the surface of the heat exchanger and other process equipment through which the fluid flows, the deposit rate is reduced, thereby reducing the scale, fouling, and others of the wall of the heat exchanger / process equipment. Reducing / preventing the formation of solid deposits of the type This is thought to be due to the large flow rate at the solid-liquid interface (heat exchanger wall) carrying away most of the solid sediment in the bulk stream.

  Surprisingly, the effect of the small increase in flow velocity obtained by eliminating the electrical contribution to the fluid friction factor can effectively reduce the deposit rate of deposits, so that the present invention can be applied to heat exchangers and other It is an effective tool for addressing scaling / fouling issues in other process equipment. Such a small increase in flow rate is usually on the order of 1 to 10%, and it does not mean that the already formed deposit can be removed by increasing the shearing action at the deposit-liquid interface. .

  The results of these amazing studies are devoted to the prior art methods of using electromagnetic fields / electromagnetic potentials to prevent fouling / scaling. This is because conventional methods make the electromagnetic field / electromagnetic potential sufficiently strong and act on the bulk liquid, thereby promoting nuclear clustering and precipitation of the mixture formed by scale and / or dirt in the process liquid. This is because it focuses on carrying away sediment with bulk flow. In this case, however, the chemical state of the process fluid must be changed, and one or more liquid compounds are ionized or one or more electrochemical reactions are electrically generated in the process fluid. May. Therefore, the prior art should be used with caution in the process industry so as not to cause harmful side effects in the process. Another undesirable side effect of these prior art methods is that the electromagnetic field / electromagnetic potential used is almost certainly different from the electrical friction potential, so that the applied potential is almost certainly new electric. The friction potential is generated, and the friction potential is likely to be greater than the naturally occurring friction potential. This, in turn, reduces the flow rate, thereby promoting the deposit rate. This may be one explanation for the instability of many prior art methods.

  In the present invention, the applied potential is accurately canceled with the electric frictional potential naturally generated by the flow. These potentials therefore cancel each other, so that the process liquid does not contact the electric field. As a result, there is no risk of causing electrochemical changes in the process in the flowing process fluid, including changes in chemical equilibrium, compound ionization, radical generation, induction of unwanted chemical reactions, and the like. The naturally occurring electrical triboelectric potential is usually low, on the order of +/− several volts or less, and therefore can be processed with a magnetic field that is much less powerful and therefore energy efficient than prior art methods. The method according to the invention is therefore not at all risky from both an electrochemical and handling safety point of view and is therefore suitable for any devisable process, regardless of the type of process liquid flowing through the process equipment.

  Another advantage over the prior art is that the present invention is based on scientific knowledge, so that the method according to the present invention is well controllable and provides stable results. As a further advantage, the present invention does not add or remove any substances in practicing the present invention or induce chemical reactions in the process fluid that may have undesirable and deleterious effects on the process and / or environment. It does not cause pollution problems.

   In the case of process liquids containing chemically active components, there are usually other naturally occurring potentials that need to be considered. When a metal (for example, a heat transfer surface) is immersed in a solution (fluid), a potential is established between the surface of the metal and the solution, that is, the surface is charged. Most metals are usually negatively charged and the potential can be measured in conjunction with a comparison cell (eg, standard calomel comparison cell, SCE). This potential is termed the corrosion potential. When the surface is charged, further attachment appears, which occurs due to the attractive force between the surface charge and counterions or / and dipole molecules in the fluid [13]. These phenomena are an additional contribution to the electrical friction factor for the fluid flow at the heat transfer surface and should be addressed by the applied DC magnetic field. Therefore, in the present application, the term “electrical factor” means the combined action of the corrosion potential and the frictional potential due to the fluid flow involved in all the frictional factors relating to the fluid flow.

  The present invention relates to all types of heat exchangers (HE), including air-cooled heat exchangers, plate and frame heat exchangers, compact heat exchangers, shell and tube heat exchangers, Includes heavy tube heat exchangers, spiral heat exchangers, shell and tube condensers, air cooled condensers, plates and small condensers, direct contact condensers, cooling towers, steam generators, boilers, and evaporators. The invention also relates to either the process fluid side or the cooling / heating medium side or both sides of the heat transfer surface. In addition, all other types of industrial and non-industrial process equipment are included, where process liquids flow and scaling / fouling can be a problem.

  Therefore, in summary: the concept of the present invention is to employ a DC potential that accurately cancels the combined accumulation of potential and corrosion potential due to friction from the flowing fluid. Thus, the potential is reduced to zero across the boundary layer (at the liquid-wall interface), thereby reducing the electrical contribution to friction due to fluid flow at the surface to zero. As a result, the flow rate near the surface can be maximized, thereby also reducing / removing the deposition rate of suspended sediments. The spontaneous potential at the liquid-solid interface is less than ± 5V, but typically less than ± 2.5V, and often in the order of less than ± 1.0V.

  In order to implement the inventive concept, the inventive method may be implemented in an apparatus comprising a control unit, which ensures that the applied DC potential is naturally generated at the liquid-solid boundary. Counter the potential accurately. The control unit comprises three parts: a measurement / calculation unit, an electrical DC potential generator, and a regulator. These components do not need to be further described in some conventional types. A similar system is fully disclosed in US Pat. No. 6,334,957 or the corresponding European Patent No. 1021376 (EP1021376). In the regulation unit, the magnitude of the applied DC potential is calculated from information on the fluid properties measured upstream of the pipe / duct portion exposed to the DC magnetic field. The measured fluid property may be one or more properties included in the group consisting of average flow rate, corrosion potential, pH, concentration of specific ions contained in the fluid, conductivity, pressure and temperature.

  The invention will now be described in more detail with reference to preferred embodiments of the invention.

  As a preferred embodiment of the present invention, FIG. 1 schematically shows a case where it is implemented by a shell and tube heat exchanger. Arrows indicate the direction of flow. Invention 1 is coupled to heat exchanger 2 by two or more conventional connectors (not shown). One connector is connected to the ring 4 with an inlet for the cooling / heating medium 3 that is electrically isolated from the other system. One connector is connected to the ring 7 with an inlet for process fluid 6 that is electrically isolated from the other system. The third connector is connected at point 9 marked on the heat exchanger itself. When the process fluid flow is improved using the present invention, a connection point 9 is provided at the outlet for the process fluid 5. In order to improve the cooling / heating medium flow, a connection point 9 is provided at the outlet 8. Ring 4 is used to improve cooling / heating medium flow, and ring 7 is used to improve process fluid flow.

When switching the present invention to measurement / calculation mode, the set point of the regulator is determined as described below:
The set point is predicted based on capacitance measurements. The capacitance is measured by the alternating current method between the ring 4 or 7 and the heat exchanger 9 itself and is a function of the applied direct current potential. Its positive (+) end and negative (-) end are connected to 9 and 4 or 7, respectively. The potential at the point where the electrostatic capacitance is at a minimum value is made to correspond to a non-energized heat exchanger, and this potential is a specific DC potential used as a set point for the regulator. When the present invention is switched to the operation mode, a potential is applied between 4 or 7 and 9 by an electric DC generator, and the generator is controlled by a regulator.

(Verification of invention)
In order to verify the ability to reduce deposit adhesion according to the present invention, a colloidal solution of calcium carbonate and barium sulfate was poured into water and an experiment was conducted to investigate the adhesion rate on the titanium surface. Calcium carbonate and barium sulfate are dispersed (in colloidal state) in the flowing fluid and passed through the titanium plate.

(Experiment)
Solution Prepare a colloidal solution of calcium carbonate and barium sulfate: 1 L of 0.00025 mol of barium chloride (BaCl ₂ ) and 1 L of 0.00025 mol of calcium chloride (CaCl ₂ ) and then 1 mol of sodium carbonate (Na ₂ CO _3). ) Add 2.5 ml. Finally, 25 ml of 0.01 mol sodium sulfate (Na ₂ SO ₄ ) is added. In this way, a colloidal solution of calcium carbonate and barium sulfate is obtained. Using fresh solution and at room temperature, light scattering measurements are performed at different wavelengths, and the size of the calcium carbonate and barium sulfate particles is about 50 nanometers (nm). In 2-3 days, the size of these particles reaches about 100 nm. When the size is further increased, the colloidal state is converted to the suspended state, and precipitation of calcium carbonate and barium sulfate is observed. Thereafter, the colloidal solution is replaced with a newly prepared solution.

  When the experiment was conducted at 38 ° C., particle size growth and precipitation was very rapid. Therefore, a new solution was used every day.

  During the measurement, the contents of calcium and barium were controlled by atomic absorption spectrometry.

Flow system The layout of the liquid flow system is shown in FIG. The piping is loop-shaped, and the loop includes two reservoirs that receive the simulated fluid and a peristaltic pump (P). The flow rate is controlled by the height (H), while the liquid temperature is controlled by the thermoreservoir 2. This reservoir also helps to avoid periodic pressure changes that occur during the operation of the peristaltic pump and can affect the crystal oscillation frequency.

Electrode and measurement 5 MHz AT-cut quartz crystal having a diameter of 15 mm and a thickness of 0.3 mm was used.
Both sides of the quartz piece were coated with titanium by cathode sputtering. The decrease in frequency variation is linearly related to the increase in electrode mass. From the fundamental frequency of the crystal resonator (5 MHz) and the geometric area (0.2 cm ⁻² ) of the circular titanium region at the center of the crystal piece, the EQCM mass sensitivity is 25 · 10 ⁻⁹ gHz ⁻¹ cm ⁻² = It becomes equal to 25 ngHz ⁻¹ cm ⁻² . These coated working quartz resonators (QCM1, QCM2 and QCM3, see FIGS. 3 and 4) were glued to a cylindrical holder and the holder was secured to the pipe in three different ways (see FIG. 3). One side of the quartz piece was exposed to the solution in a pipe to obtain a working electrode (QCM1, QCM2, and QCM3, see FIGS. 3 and 4). The other side of these quartz pieces was exposed to air.

  The working crystal electrodes were inserted into three separately controlled oscillator-QCM drivers (FIG. 4). With this structure, the working electrode can be grounded. A homemade voltammetry and frequency measurement system was used (Figure 4). In this system, measurement was performed at a frequency of about 5 MHz in 3 ms with an accuracy of 0.1-0.2 Hz by a high-accuracy frequency counter.

  During the measurement, the same potential was simultaneously applied to all three electrodes, and the time-dependent changes in the frequency of the electrodes carried on these crystals were recorded separately every 600 seconds. Thereafter, the same experiment was repeated for the other electrode. In this way, the relationship between the potential range of 1 V to -1 V and the standard hydrogen electrode (0.8 V to -1.2 V versus silver / silver chloride / saturated KCl electrode) was investigated by increasing by 0.1 V.

Result 1. Measurement at a flow rate of 3 L / min (Reynolds number = 1300) in a colloidal solution at room temperature (22 ° C.) These measurement results are shown in FIGS.

  It can be explained that the low rate observed when the potential was most positive with fresh colloidal solution would be due to very small particles (less than 50 nm). During the measurement, the particles were growing (growth followed by light scattering). That may be the reason for the high rate when the potential changes in the negative direction but still remains in the positive region. When the experiment is repeated on the next day and the third day with the same solution, the influence of the potential on the mass adhesion rate in the positive region is reduced (FIGS. 8 and 9).

  Obvious potential effects are observed in the negative potential region—the mass deposition rate is significantly reduced (FIGS. 5, 8 and 9).

  The same solution and measurement conditions used in FIGS. 8-5, but the measurement was performed the day after the experiment. The result is shown in FIG. The particle size is about 100 nm, which is very slow but still growing. The data displayed in FIG. 8 shows the effect of potential (the effect of growth is small). Figure 9-The solution turns more milky white, the particle size is larger than 100 nm, the solution turns more milky white (solution whitening is visually observed).

  The rate of mass adhesion to these electrodes was very low, similar to the first two days (FIGS. 6 and 7). The measurement was repeated on the third day (data relating to the bottom electrode is shown in FIG. 9), and the measurement results showed some similarities with the bottom electrode response, but the absolute values of the proportions were significantly lower.

2. Measurement in a colloidal solution at a flow rate of 4 L / min (Reynolds number = 1700) and room temperature (22 ° C.) These measurement results are shown in FIGS.

  A decrease in deposition rate was observed at higher flow rates (FIGS. 10 and 11), which may be related to particle “cleaning” from the electrode surface.

  Both experiments 1 and 2 were performed in laminar flow (Reynolds numbers are 1300 and 1700). In laminar flow, the coefficient of friction decreases as the Reynolds number increases. A decrease in adhesion rate was observed at higher flow rates (FIGS. 9 and 10), which may be associated with a lower coefficient of friction.

From the conclusion results, the adhesion rate of calcium carbonate and barium sulfate to the electrode surface depends on the applied electric DC potential within the range of 0.8 to 1.0 V (Ag / AgCl ₂ reference electrode). I understand. Within a certain range, a decrease in adhesion rate is observed, while an increase is observed in other ranges.

  The results show that the adhesion rate decreases with increasing flow rate, which suggests that these effects are probably associated with a lower coefficient of friction.

Citation 1) Müller-Steinhagen, H. (Miiller-Steinhagen, H.) (2000). "Heat Transfer Fouling" translated version 14 February 2003:
http://www.cpe.surrey.ac.uk/dptri/hms/fouling.htm
2) "Evaluation of the principles of magnetic water treatment", American Petroleum Institute, Washington DC. 1985 (API Publication 960)
3) Gamayunov, N. Ai. (Gamayunov, NI) “Enlargement of Particles in Water Streams Under the Influence of Crossed electric and magnetic fields), Journal of Applied Chemistry (J. Appl. Chem.) No. 57, 1984.
4) Baker, Jay. S. (Baker, JS), Jado, S. Jay. (Judd, SJ) "Magnetic amelioration of scale prevention", Water Research (Vol. 30), 1996.
5) Parsons, S. A. (Parsons, SA), One, B.L. (Wang, BL), Jado, S. Jay. (Judd, SJ), Stephenson. tea. (Stephenson. T.) “Magnetic treatment of calcium carbonate scale-effect of pH control”, Water Research (Wat. Res.) 31, 1997.
6) Quinn, See. Jay. (Quinn, CJ) "Magnetic treatment of water prevent mineral build-up", Iron and Steel Engineer, Volume 74, 1997.
7) Barrett, Earl. A. (Barrett, RA), Parsons, S. A. (Parsons, SA) “The Influence of Magnetic Fields on Calcium Carbonate Precipitation”, Water Research (Vol. 32) 1998.
8) Koy, Jay. M. Di. (Coey, JM D.), Kas, S. (Cass, S.) “Magnetic water treatment” Journal of Magnetics and Magnetic Materials, J. Magn. Mater. No. 209, 2000.
9) Gabrielli, See. (Gabrielli, C.), Jaohari, Earl. (Jaouhari, R.), Kedam, M. (Keddam, M.) "Magnetic water treatment for scale prevention", Water Research (Vol. 35, 2001).
10) Kobe, S. (Kobe, S.), Dragjik, G. (Drazic, G.), McGuinness, Pea. Jay. (McGuiness, PJ), Strategic, Jay. (Strazisar, J.) “The Influence of the Magnetic Field on the Crystallization Form of Calcium Carbonate and the Testing OSA Magnetic Water. -The influence of the magnetic field on the crystallization form of calcium carbonate and the testing of a magnetic water-treatment device, Journal of Magnetics and Magnetic Materials (J. Magn. Magn. Mater.) No. 236, 2001.
11) Hewitt, G. F. (Hewitt, GF), Shires, G. El. (Shires, GL), bot, tee. R. (Bott, TR) "Process heat transfer" CRC Press, Boca Raton, 1994.
12) Hasson, Di. (Hasson, D.), Bramson, Di. (Bramson, D.) “Effectiveness of Magnetic Water Treatment in Suppressing CaCO ₃ Scale Deposition” Industrial and Engineering Chemistry Process Design and Development (Ind. Eng. Chem. Process Des. Dev.), 24, 1985.
13) Bokuris, Jay. Oh. M. (Bockris, JOM), Lady, A. Kay. N. (Reddy, AKN), “Modern Electrochemistry, Vol. 2A, 2nd Edition (Modern electrochemistry, vol. 2A, 2nd Ed.)”, New York, Kluwer Academic / Plenum Publishers, 2000 .

It is the schematic at the time of implementing this invention with a shell and tube heat exchanger. FIG. 2 is a layout diagram of a liquid flow system. It is a piping dimension and an electrode position. It is a block diagram of an EQCM system. The dependence relationship between the mass adhesion rate and the potential (lower electrode) in the fresh solution was shown. The dependence relationship between the mass adhesion rate and the potential (top electrode) in the fresh solution was shown. The dependence relationship between the mass adhesion rate and the potential (side electrode) in the fresh solution was shown. The dependency relationship (the second day after preparing a colloidal solution of calcium carbonate and barium sulfate) between the mass adhesion rate and the potential (lower electrode) at a flow rate of 3 L / min was shown. The dependency relationship (the third day after preparing a colloidal solution of calcium carbonate and barium sulfate) between the mass adhesion rate and the potential (lower electrode) at a flow rate of 3 L / min was shown. The dependency relationship (the third day after preparing a colloidal solution of calcium carbonate and barium sulfate) between the mass adhesion rate and the potential (lower electrode) at a flow rate of 4 L / min was shown. The dependency relationship (the third day after preparing a colloidal solution of calcium carbonate and barium sulfate) between the mass adhesion rate and the potential (top electrode) at a flow rate of 4 L / min was shown. The dependency relationship (the third day after preparing colloidal solutions of calcium carbonate and barium sulfate) between the mass adhesion rate and the potential (side electrode) at a flow rate of 4 L / min was shown.

Explanation of symbols

(Figure 1)
1 Invention 2 Thermo tank, heat exchanger 3 Cooling / heating medium 4, 7 Ring 5, 6 Process fluid 8 Outlet 9 Connection point

Claims (9)

Applying a direct current (DC) potential to the pipe / duct wall removes electrical contribution to the friction factor and adjusts the applied direct current potential by an adjustment unit to which the measured fluid property information is supplied A method for reducing fouling and / or scaling in a process equipment containing a fluid, comprising:
Constantly adjusting the applied direct current potential, whereby the applied direct current potential is a naturally occurring potential due to the accumulation of charge on the wall from the interaction between the flowing fluid and the wall material; A method characterized by having exactly the same strength but opposite polarity.   Supplying the conditioning unit with fluid properties measured upstream of the pipe / duct section exposed to a DC magnetic field, and the measured fluid properties are contained in an average flow rate, corrosion potential, pH, fluid; The method of claim 1, wherein one or more of the characteristics included in the group consisting of the concentration, conductivity, pressure, and temperature of a particular ion.   The method according to claim 1, wherein the DC potential is in the range of −5.0 to +5.0 V (saturated calomel electrode, SCE).   The method according to claim 1, wherein the DC potential is in the range of −2.5 to +2.5 V (saturated calomel electrode, SCE).   The method according to claim 1, wherein the DC potential is in the range of −1.0 to +1.0 V or less (saturated calomel electrode, SCE).   The flow is a pure fluid, a colloidal fluid, a fluid containing particulate inclusions, a mixture of fluids, a single phase or a mixed phase, or a mixture of one or more of these in a gaseous or liquid state. The method according to claim 1, wherein:   7. A method according to claims 1 to 6, wherein the flow can have a Reynolds number in the range of 1 to 5,000,000.   Connecting a DC potential generator to an electrically insulated portion of the pipe / duct wall with one polarity and to the pipe portion downstream of the insulation portion with the other polarity; and the DC potential generator 8. A device for carrying out the method according to claim 1, characterized in that it is controlled by an adjustment unit to which the measured value of the fluid property upstream of the part exposed to direct current potential is supplied. Supplying the conditioning unit with one or more of the characteristics included in the group consisting of average flow rate, corrosion potential, pH, concentration of specific ions contained in the fluid, conductivity, pressure and temperature. The apparatus according to claim 8.

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