CN109520362B - Shear elastic wave online scale prevention and removal system and scale prevention and removal method - Google Patents

Abstract

The invention discloses an online antiscaling and descaling system for shear elastic waves, which comprises: the system comprises an alternating current power supply, a rectifying and filtering circuit, an inverter circuit, a DSP micro-processing system, an A/D conversion circuit, a transducer, a harmonic sampling circuit and an A/D conversion circuit; the invention further provides an anti-scaling and descaling method of the shear elastic wave online anti-scaling and descaling system, which is characterized in that the anti-scaling and descaling method is sent to a DSP micro-processing system through an A/D conversion circuit, the DSP micro-processing system finds all vibration mode harmonic response frequency points of the descaled equipment through signal calculation and processing, and controls an excitation transducer of frequency F alternating current electric pulses output by an inverter circuit, so that the descaled equipment obtains shear elastic waves with maximum efficiency and the effect of efficient descaler. The invention has high descaling and antiscaling efficiency, low cost and little pollution.

Description

Shear elastic wave online scale prevention and removal system and scale prevention and removal method

Technical Field

The invention belongs to the technical field of descaling and antiscaling, and particularly relates to an on-line descaling system and method for descaling by shear elastic waves.

Background

The heat transfer and mass transfer are indispensable processes in the process flow, the heat exchanger is necessary equipment for heat transfer, and the heat exchanger transfers heat by taking a material with excellent heat conduction as a heat exchange surface. Fouling is the layer of solid or soft, muddy material attached to the heat exchange surface, which is usually present in the form of a mixture, and the process of fouling formation is the process of the heat exchange surface from a clean state to being covered with fouling, which is widely present in industrial production processes. Fouling not only hinders heat transfer to increase resistance of the fluid flowing through the heat exchange surface, but also severely hinders normal operation of the equipment and causes huge waste of energy and economic losses.

Chemical scale prevention and removal techniques have long been widely used and have been effective to some extent. But also exposes some problems, such as pollution of receiving water body, increase of solid waste and generation of new pollutants, and breeding of bacteria and algae when the temperature is proper, caused by adding chemical agents into cooling water; the chemical method only plays a role in relieving the dirt treatment of the industrial process, for example, periodic pollution discharge is needed to keep the good state of circulating water, and a large amount of new water is supplemented.

The principle of the technology is that a certain amount of energy is applied to circulating water through the technologies of an electric field, a magnetic field, a sound field, electrochemistry and the like, the formation of scale is inhibited by promoting the crystallization of the scale in a water body or breaking down the scale at the initial stage of the formation, the technology can be treated on line, and chemical waste liquid is not generated. Has the effects of slight antisepsis, scale dissolution, sterilization and algae removal. The physical method has the following defects: the treatment effect is related to the water quality, the effect on hard water is not obvious, the hard water has failure problems, under-deposit corrosion sometimes occurs, the application environment temperature is strictly limited, the hard water cannot be used in a phase change environment, and in addition, the descaling effect on soft deposits such as silt, biological slime and the like is not realized. The water circulating system is only used for a circulating water system with low hardness, but not used for a water system with high hardness (such as a sewage evaporation system), and the water circulating system is incapable of solving the problems of scabbing, carbon deposition, dust deposition, valve locking and the like of a heat exchanger or a pipeline.

The online installed external short pulse ultrasonic scale prevention and removal technology comprises the following steps: the working principle is that the ultrasonic energy is transmitted to the heat exchange wall surface by the ultrasonic transducer arranged outside the heat exchanger, and a series of physical effects are generated, wherein the most important is the shearing effect. The ship boiler is generally a steam boiler, the elasticity of the heat exchange tubes of the boiler is good, the boiler water is treated, the scaling degree is not very serious, the scaling temperature is very high, but after a layer of thin scale is generated, cracks can be generated under the action of a very small pulse external force, and after hot water enters the cracks, steam explosion is generated under the action of a high-temperature tube wall to impact the scale, so that a good scale preventing and removing effect is realized. However, the scaling condition of the heat exchanger in the petrochemical field is more complicated than that of a steam boiler, the boiler scaling is generally inorganic salt scaling, the scaling of the heat exchanger in the petrochemical field is generally composite scaling and has certain toughness and viscosity, in addition, the heat exchange temperature of the heat exchanger is lower, the phenomenon of steam explosion is avoided, the heat exchange pipe wall of the heat exchanger is rough, and the scaling treatment difficulty of the heat exchanger in the petrochemical field is determined to be much higher than that of the steam boiler by the phenomena. The external short pulse ultrasonic scale prevention and removal technology is characterized in that a capacitor charging and discharging technology is utilized to provide energy for a heat exchanger to drive an energy converter to generate ultrasonic energy, the energy converter is tightly connected with the heat exchanger to transmit the ultrasonic energy to a heat exchange wall surface, so that the heat exchange wall surface generates continuous short pulse fluctuation, the pulse working time is 2.5-5.0 ms, and the pulse interval time is 80-100 ms. Because the effective work of the ultrasonic energy is too short, the effective power density is too low, so that the surface particles of the heat exchange wall surface can not generate continuous elliptical motion, namely, the heat exchange wall surface and the dirt attached to the heat exchange wall surface can not generate good continuous mutual shearing force, namely, the energy density and the capacity for removing the dirt are very small.

Disclosure of Invention

In view of the above disadvantages of the prior art, the present invention provides an online scale prevention and removal system and method using shear elastic waves, which are used to overcome the defects of low scale removal efficiency, short service life of a heat exchanger, high cost, low production efficiency, easy introduction of secondary pollution, narrow application range, etc. in the prior art.

In order to achieve the purpose, the technical scheme of the invention is as follows:

an online anti-scale and descaling system with shear elastic waves comprises:

the alternating current power supply is used for providing working voltage for the shear elastic wave online scale prevention and removal system;

the rectification filter circuit is used for processing the alternating current into direct current;

an inverter circuit;

the DSP micro-processing system controls the inverter circuit to convert direct current into alternating current pulse signals with variable time length T, frequency F and voltage V, processes electric signals transmitted by the A/D conversion circuit, harmonically responds to and analyzes descaled equipment, finds all vibration mode harmonious response frequency points of the descaled equipment, and controls the inverter circuit to output alternating current pulses with frequency F and excite the transducer;

the energy converter converts the alternating current pulses with the time length T, the frequency F and the voltage V into mechanical pulse elastic waves with the time length T, the frequency F and the amplitude A, and excites descaled equipment connected with the energy converter to generate a series of pulse harmonic waves;

the harmonic sampling circuit is used for collecting pulse harmonic response points on the descaling equipment and converting the pulse harmonic response points into electric signals;

and the A/D conversion circuit feeds the electric signal converted by the harmonic sampling circuit back to the DSP micro-processing system.

Furthermore, the working frequency of the mechanical pulse elastic wave is 10 kHz-35 kHz, and the pulse working time is never less than 10 ms.

Furthermore, the transducer is made of magnetostrictive materials with the temperature of not lower than 700 ℃ through welding processing.

Further, the transducer is directly or indirectly arranged on the descaled equipment.

An anti-scaling and descaling method adopting a shear elastic wave on-line anti-scaling and descaling system comprises the following steps:

firstly, processing an alternating current 220V power supply into stable direct current through a rectifying and filtering circuit;

step two, the DSP micro-processing system controls the inverter circuit to convert the direct current into alternating current pulse signals with variable time length T, frequency F and voltage V;

step three, exciting the transducer by the alternating current pulse signal, converting the alternating current pulse with the time length T, the frequency F and the voltage V into mechanical pulse elastic waves with the time length T, the frequency F and the amplitude A, and generating a series of pulse harmonic waves after the descaling equipment is excited by the mechanical elastic pulse waves;

converting the pulse harmonic response point into an electric signal by a harmonic sampling circuit;

feeding the electric signal converted by the harmonic sampling circuit back to the DSP micro-processing system by the A/D conversion circuit;

and sixthly, the DSP micro-processing system performs harmonic response analysis on the descaled equipment, finds all vibration mode harmonic response frequency points of the descaled equipment, and controls the frequency F of the alternating current electric pulse output by the inverter circuit to excite the transducer.

The ultrasonic scale prevention and removal technology has the advantages that the power sound wave energy is transmitted through the metal material of the heat exchanger (or pipeline), the transmission speed of the sound wave in the metal is more than 3 times of that in water and more than 120 times of that in air, and the attenuation rate in the metal is far less than that in water and air; the ultrasonic wave is favorable for propagation in metal materials, the ultrasonic wave can cause micro-vibration of metal particles when transmitted in the metal, and according to the characteristics of the scaling process of the heat exchanger (or pipeline), the scaling substances in the heat exchanger (or pipeline) are separated out after supersaturation and gradually adhere to the inner wall of the heat exchange pipe. The transmission waveform of the ultrasonic wave in the metal mainly has three forms, namely a short pulse waveform, a long pulse waveform and a constant-power smooth waveform.

Different power acoustic waveforms have different functional characteristics, as explained below:

short pulse: the short pulse antiscaling and descaling technology features that the work time of power sound wave is short, usually below 5ms, and the pulse interval time is long, usually about 80ms, so that the transducer may be powered by capacitor. Based on the characteristics, the short pulse has larger instantaneous power but very small continuous power density, and has the advantages of small heat productivity of control equipment and a transducer, small power consumption, and much smaller transmission distance in metal compared with a long pulse technology, and when power sound wave energy is transmitted on the surface of a metal heat exchange tube, metal particles can not generate continuous elliptical motion but only weak intermittent elliptical motion, so that the shearing effect mainly used for preventing and removing scale is very weak, namely the scale preventing and removing capacity of the short pulse technology is very weak, and the short pulse heat exchange tube can only be used in the field with very small scale preventing and removing speed or not serious scale. In addition, in order to obtain higher energy density in practical application, the short pulse technology is used for treating the heat exchanger with serious fouling, and the installation number of the transducers is required to be increased, so that the construction workload on the site is increased, the problem of interference between sound waves of the output power of the transducers is not easy to solve, and the problem of mutual offset is easy to generate.

Long pulse: the long pulse antiscaling and descaling technology is an upgrading technology of short pulse antiscaling and descaling technology, and not only the inherited short pulse antiscaling and descaling technology forms certain pulse disturbance to a heat exchange surface when being transmitted in metal, but also the pulse disturbance is stronger. The long-pulse scale prevention and removal technology adopted by the invention is characterized in that the working time of the power sound wave is longer, generally 10ms or more, and continuous pulse can be realized, and the pulse interval time is shorter than the effective working time, generally about 100ms, so that the power supply requirement of a transducer can not be met by using a capacitor charging and discharging mode, and the power supply of a circuit which needs larger power and can generate continuous power pulse can be realized. Based on the characteristics, the instantaneous power of the long pulse is also larger, the continuous power density is also larger, the defects are that the control equipment and the transducer have larger heat productivity, the heating problem can be effectively solved by adopting measures such as a radiating fin and the like, the complex water cooling measure is not needed, the transmission distance in the metal is longer than that of a short pulse technology, the attenuation is small, when the power sound wave energy is transmitted on the surface of the metal heat exchange tube, as shown in the figure, the long pulse scale prevention and removal technology of the invention applies a pulse waveform of more than 10ms or continuous to the heat exchanger or the pipeline, the waveform can enable metal particles to generate continuous elliptical motion, the maximum amplitude of the elliptical motion is not more than 5 micrometers, the vibration energy is within 1/10 of the metal fatigue period, the elastic wave can be ensured to be transmitted in the metal, namely, the long pulse scale prevention and removal technology of the invention plays a leading role in the elastic shear wave in the scale prevention process of the heat exchanger or the pipeline, the safe operation of the descaling and antiscaling equipment can be absolutely guaranteed, and the service life of the descaling and antiscaling equipment is not affected. The heat exchange surface of the metal particle continuous elliptic motion has a good shearing effect, so that the shearing effect mainly used for scale prevention and removal is very large, namely the peeling capacity of scale is very good.

In addition, the long-pulse anti-scaling and descaling technology provided by the invention has a wider design for applying working frequency to a heat exchanger or a pipeline, and can meet heat exchange equipment with different metal materials and different structures, different scaling speeds and different scaling characteristics, and different parameters such as temperature, pressure, PH value, hardness and the like in practical application at 10 kHz-35 kHz; different on-site scaling problems need different parameters of anti-scaling and descaling equipment, and due to the characteristics of the long-pulse anti-scaling and descaling technology, the technology can realize frequency-conversion phase-shift multi-peak output in practical application, and can provide proper output parameters according to different characteristics of on-site descaled equipment so as to realize the optimal anti-scaling and descaling effect, namely the long-pulse technology has very good on-site adaptability.

Constant power smooth waveform: the control circuit of the power acoustic wave technology of the waveform is relatively simple, and is generally suitable for being used on power ultrasonic biochemical equipment or applied to the fields of ultrasonic processing and the like. The waveform power acoustic wave equipment generally has larger output power, large power consumption and large heat productivity and needs water cooling. The waveform power acoustic wave technology is not suitable for the field of scale prevention and removal of heat exchangers, and firstly, because the power of a single energy converter is higher, the single energy converter is applied to the heat exchanger, the partial acoustic wave power of the heat exchanger is higher, so that inelastic fluctuation is easily caused, and the service life of the heat exchanger is influenced; when the waveform power acoustic wave technology is transmitted in metal, the heat productivity is large, the energy loss is large, and the attenuation is fast. The most important point is that the displacement distance of metal particles is small when the waveform power acoustic wave technology is transmitted in metal, and the metal particles only fluctuate near a vibration balance point but cannot generate regular elliptical motion of the metal particles, so that good shearing force cannot be generated; in addition, because of the balanced wave energy transmission, the metal wall surface and the dirt are easily in a new balanced state, the disturbance quantity between the metal wall surface and the dirt is small, and the dirt removing and preventing capacity is weakened.

The invention has the positive and progressive beneficial effects that:

1. the invention adopts the power sound wave long pulse technology, has the characteristics of frequency conversion, phase shift, multi-peak value and wide frequency band, and compared with the short pulse waveform technology and the smooth waveform technology, the attenuation is small in the metal transfer process, the transfer distance is long, and the surface particles of a heat exchanger or a metal pipeline generate elliptic motion, so that the metal surface generates larger shearing force, and the invention has strong anti-scaling, anti-scar and anti-scar capabilities;

2. the transducer is formed by welding magnetostrictive materials with the temperature higher than 700 ℃, has few fault points, unattenuated long-term use performance, low power consumption and long service life in the use process, and can be continuously used for more than 10 years;

3. the invention adopts the distributed transducers to transmit elastic waves in metal, the amplitude is generally not more than 5 mu m, the installed equipment has no stress concentration and no damage to the equipment for descaling and antiscaling;

4. the power sound wave long pulse technology used by the invention has the characteristics of wide frequency band and long transmission distance, and the transducer can be directly welded, or connected through a special joint, or connected with equipment to be descaled and antiscaled in various forms through a special fixture and the like, not only can be installed and used on the equipment to be descaled and antiscaled for a long time, but also can be used as a tool, and can quickly and online eliminate the problems of valve blockage, non-adjustment of an adjusting valve, pipeline blockage and the like;

5. the descaling and antiscaling device is not only suitable for descaling and antiscaling of heat exchangers and pipelines in the industrial field, but also suitable for design processes of flow industries such as petrochemical industry and the like, reduces or eliminates production halt of enterprises caused by the problems of dirt, scabbing, carbon deposition and the like in the flow industries, improves product quality, and has great significance for energy conservation, emission reduction and the like.

Drawings

FIG. 1 is a schematic view of the mounting of a transducer of the present invention on a fixed tube and plate heat exchanger.

Fig. 2 is a schematic view of the transducer of the present invention mounted on a U-tube heat exchanger.

Fig. 3 is a schematic view of the installation of the transducer of the present invention on a floating head heat exchanger.

FIG. 4 shows the transducer of the present invention vertically connected to a small shell and tube heat exchanger.

FIG. 5 shows the transducer of the present invention connected at an angle to a small shell and tube heat exchanger.

Fig. 6 shows the connection of the transducer according to the invention to a plate heat exchanger.

Fig. 7 shows the connection of the transducer of the present invention to a spiral plate heat exchanger.

FIG. 8 is a schematic view of the descaling and antiscaling process according to the present invention.

Detailed Description

Working process of on-line scale prevention and removal system adopting shear elastic waves

As shown in fig. 8, an ac 220V power supply is processed into a stable dc power by a rectifying and filtering circuit, and the DSP micro-processing system controls an inverter circuit to convert the dc power into an ac power pulse signal with variable time length T, frequency F, and voltage V; the AC pulse signal excites the energy converter, the AC pulse of time length T, frequency F and voltage V is converted into mechanical pulse elastic wave of time length T, frequency F and amplitude A, because the energy converter and the descaling equipment are tightly connected (welded) to form a whole, the mechanical pulse elastic wave is transmitted to the heat exchange surface in the descaling equipment, after the descaling equipment is excited by the mechanical elastic pulse wave, a series of pulse harmonic waves can be generated, the pulse harmonic waves have frequency conversion and phase shift performance, and the pulse working time and interval time of the harmonic waves can be controlled by the DSP micro-processing system to be long or short, in order to realize better scale prevention and removal effect. In actual work, the frequency of the harmonic output by the transducer corresponds to various vibration mode harmonic response points of the descaled equipment, the vibration mode harmonic response points are converted into electric signals by the harmonic sampling circuit and are sent to the DSP micro-processing system through the A/D conversion circuit, the DSP micro-processing system carries out harmonic response analysis on the descaled equipment through signal calculation processing, all vibration mode harmonic response frequency points of the descaled equipment are found, the frequency F of alternating current electric pulses output by the inverter circuit is controlled to excite the transducer, the frequency output of the transducer is ensured to be switched at the frequency points, and therefore the descaled equipment can obtain shear elastic waves with the maximum efficiency, and the effect of efficient descaled is achieved.

(the DSP micro-processing system is an intelligent generating system with waveform output, and can output control signals with different frequencies by setting a program and comparing micro resonance frequency feedback signals of the heat exchanger, the signals control the inverter circuit to convert power into power driving signals and then drive the energy converter to convert the power into elastic shear waves to be transmitted in metal;

within a set frequency interval, the output frequency of the controller can be changed from low to high and also from high to low, namely, the frequency sweeping function of the shear elastic wave is realized, so that the problem of low energy and the problem of effective transmission of the energy wave at the wave trough in the metal transmission are effectively solved. Because the heat exchangers with different shapes made of nonmetal have different microscopic resonance frequencies, the elastic shear waves can be effectively transmitted only when the frequency output by the DSP micro-processing system and the microscopic resonance frequencies of the heat exchangers, and the effective scale prevention and removal effect is achieved

The frequency of the elastic shear wave output by the DSP micro-processing system can be fixed and can also be changed in a sweep frequency mode)

The method for preventing and removing scale of the technology of the invention prevents the adhesion of various scales and removes various scales by the shear elastic wave generated by the elliptic motion of the mass point of the heat exchange surface. The scale inhibitor is basically not influenced by factors such as pressure, temperature, viscosity, flow velocity, pH value and the like, so that the scale inhibitor has broad-spectrum scale prevention and removal capability.

Example 1

The embodiment is an application of the descaling and antiscaling method of the on-line descaling and antiscaling system by using shear elastic waves to a shell-and-tube heat exchanger: the shell-and-tube heat exchanger is the most common heat exchange equipment in the process industry, and some of the heat exchangers have tube side fouling and some have shell side fouling according to different application modes. In the field with slight scaling degree, the conventional chemical dosing technology or the electronic scale prevention and removal technology is effective, but in the actual production field, the scaling of a plurality of heat exchangers is very serious, the heat exchangers are blocked for more than half a couple of days after running, the shutdown is needed for maintenance and cleaning, the yield is seriously influenced, and a large amount of energy is wasted. For example, the technology of the invention is applied to a sewage evaporator or a reboiler with very serious scale formation, and can ensure the long-term non-scale operation of the sewage evaporator and the reboiler. The shell-and-tube heat exchanger is roughly divided into a fixed tube plate type, a floating head type and a U-shaped tube type:

fig. 1 is a schematic view of the mounting of a transducer 2 on a fixed tube-plate heat exchanger 11. The flange and the tube plate of the fixed tube-plate heat exchanger 11 are integrated, the flange is provided with bolt holes, the bolt holes are avoided when the energy converter 2 is welded, and the energy converter 2 is uniformly arranged on the edge of the tube plate, so that the uniform transmission of power sound waves is facilitated. The number of the transducers 2 is determined by the structure, material, scaling speed and scaling characteristics of the fixed tube-plate heat exchanger 11.

Fig. 2 is a schematic view of the transducer 2 mounted on a U-tube heat exchanger 12. The flanges of the U-tube heat exchanger 12 and the tube sheet are not integral, the tube sheet is clamped by the two flanges, and the transducer 2 is welded to the tube sheet. The transducers 2 are uniformly arranged on the edge of the tube plate, so that uniform transmission of power sound waves is facilitated, and the installation number of the transducers 2 is determined by the structure, material, scaling speed and scaling quality of the U-shaped tubular heat exchanger 12.

Fig. 3 is a schematic view of the transducer 2 mounted on the floating head heat exchanger 13. The flange and the tube plate of the floating head heat exchanger 13 are not integrated, the tube plate is clamped by the two flanges, and the transducer 2 is welded on the tube plate. The transducers 2 are uniformly arranged on the edge of the tube plate, which is beneficial to uniform transmission of power sound waves. The number of transducers 2 to be installed is determined by the structure, material, scaling rate and scaling characteristics of the floating heat exchanger 13.

Example 2

The descaling and antiscaling method of the shear elastic wave online descaling and antiscaling system is applied to pipelines, valves and small shell-and-tube heat exchangers:

in the industrial production process, the problems of blockage of pipelines, valves and small shell-and-tube heat exchangers frequently occur due to scaling or scabbing and the like. As shown in fig. 4 below, a fixture is employed on a small shell-and-tube heat exchanger 14 to connect vertically to the transducer 2. As shown in fig. 5, the transducer 2 is attached to a small shell-and-tube heat exchanger 15 at an angle.

Example 3

Referring to fig. 6, the plate heat exchanger 6 in the present embodiment includes a plurality of heat exchange plates 61, a wave rod 68, a front clamping plate 62 and a rear clamping plate 63, and at least one transducer 2 is mounted on one end of the wave rod 68, wherein: the plurality of heat exchange plates 61 form a heat exchange plate bundle in the heat exchanger equipment frame, and each heat exchange plate 61 is tightly connected with the wave vibration rod 68. The heat exchanger equipment frame is composed of a front clamping plate 62 and a rear clamping plate 63, the heat exchange plate bundle is arranged between the front clamping plate 62 and the rear clamping plate 63, and a hot fluid inlet 64, a hot fluid outlet 65, a cold fluid inlet 66 and a cold fluid outlet 67 are formed in the front clamping plate 62 and the rear clamping plate 63. And the wave rod 68 also passes through the front and rear clamping plates 62 and 63 with a gap. The working principle is that the energy of the shear elastic wave of the transducer 2 is transmitted to the heat exchange plate 61 through the wave vibration rod 68, so that all the surface particles of the heat exchange plate 61 generate elliptical motion, and a strong shear effect is generated, thereby realizing high-efficiency scale prevention and removal effect. The number of transducers 2 and wave rods 68 installed is determined by the size of the plate heat exchanger 6 and the rate of fouling, as well as the fouling characteristics.

In addition, the above-mentioned technology and mode for transmitting shear elastic waves in the heat exchange plate 61 can also be applied to a plate-shell heat exchanger, because the heat exchange efficiency of the plate heat exchanger 6 and the plate-shell heat exchanger is very high in unit volume or unit weight, the antiscaling and descaling technology of the present invention can reduce the number of transducers and reduce the cost, but has very good antiscaling and descaling effects for the following reasons:

compared with a shell-and-tube heat exchanger, the plate heat exchanger has the advantages that the steel is light in weight and small in size, and generally cannot reach 1/3 of a shell-and-tube heat exchanger on the premise of the same heat exchange efficiency. Due to the fact that the mass of the plate type heat exchanger is small, the load of the shear elastic wave is small when the shear elastic wave is transmitted in the heat exchanger, and therefore the transmission uniformity and the transmission efficiency of the shear wave are improved. In addition, the vibration transmission rod is welded in the middle of the heat exchange plate of the plate heat exchanger in the embodiment, and the shear elastic wave is transmitted to each heat exchange plate through the vibration transmission rod, so that the energy loss of the elastic shear wave in the transmission process is very small, a part of energy is not absorbed by the shell, the end socket and the tube plate like a shell-and-tube heat exchanger, and only a part of energy is transmitted to the heat exchange tube.

Example 4

FIG. 7 is a schematic structural diagram of the descaling and antiscaling technique applied to the spiral plate type heat exchange device 7.

The spiral plate type heat exchanger 7 comprises a shell 71, a spiral plate heat exchange machine core 72 and a wave vibration plate 78, wherein a hot fluid inlet 73, a cold fluid outlet 74, a hot fluid outlet 75 and a cold fluid inlet 76 are arranged on the shell 71, the spiral plate heat exchange machine core 72 is installed inside the shell 71, the spiral plate heat exchange machine core 72 is formed by rolling metal plates which are corrosion-resistant, good in elasticity, high in heat resistance and good in heat transfer, and supporting materials are arranged between the metal plates so as to keep the distance between the metal plates uniform and can bear certain pressure. The metal sheet of spiral plate heat exchanger core 72 welds the ripples strip that shakes simultaneously in the both sides of metal sheet in the book system process, form ripples board 78 that shakes at last, transducer 2 welds on ripples board 78 that shakes, the energy of the shearing elastic wave of transducer 2 shakes on the spiral plate that board 78 transmitted spiral plate heat exchanger core 72 through the ripples, make the surperficial mass point of whole spiral plate produce elliptical motion, thereby produce very strong shear effect, in order to realize efficient scale control scale removal effect, the reason is as follows:

the embodiment is a spiral plate type heat exchanger, and the same principle as a plate type heat exchanger is adopted, and on the premise of the same heat exchange efficiency, the steel material has light weight and small volume, and generally can not reach 1/3 of a tube-shell heat exchanger. Due to the fact that the mass of the plate type heat exchanger is small, the load of the shear elastic wave is small when the shear elastic wave is transmitted in the heat exchanger, and therefore the transmission uniformity and the transmission efficiency of the shear wave are improved. In addition, the heat exchange plate of the spiral plate type heat exchanger in the case is that all the shear elastic wave energy transmitted by the tube plates formed by specially welding the upper part and the lower part is basically absorbed by the heat exchange surface, the energy of the shear elastic wave is hardly lost in the transmission process, a part of energy is not absorbed by the shell, the end socket and the tube plates like a shell-and-tube type heat exchanger, and only a part of energy is transmitted to the heat exchange tube.

The number of transducers 2 installed is determined by the size of the spiral plate heat exchanger 7 and the rate of fouling, as well as the fouling characteristics. Because the heat exchange efficiency of the spiral plate type heat exchanger 7 in unit volume or unit weight is high, the scale prevention and removal technology has good scale prevention and removal effect under the condition of reducing the number of the 7 transducers.

At present, 60% of production stop or maintenance amount in the process industries of petrochemical industry and the like is caused by scaling, blockage and the like. Taking a shell-and-tube heat exchanger as an example, only the requirements of meeting the process parameters such as pressure, temperature, heat exchange quantity and the like are considered in the design and production process, but the requirement of transmitting power sound wave energy in the heat exchanger is not considered, so that the technology of the invention needs to increase the number of installed equipment properly in the actual scale prevention and removal application, makes up the defects of the original design aspect of the heat exchanger, and achieves the satisfactory scale prevention and removal effect. The most excellent implementation case is that the technical requirements of the invention are integrated into the design process and the processing process of the heat exchanger at the initial stage of designing the heat exchanger, so that the heat exchanger not only meets the original process requirements, but also meets the requirement of transmitting power acoustic energy in the heat exchanger, the number of installed transducers can be reduced, the purpose of saving the input cost is achieved, and the optimal scale prevention and removal effect can be realized.

The shear elastic wave transmits energy waves from the outside of the heat exchanger to a position on the heat exchange surface in the online scale prevention and removal system. For example: the shear elastic wave generator is arranged on the tube plate of the shell-and-tube heat exchanger, and because the tube plate and the heat exchange tube are tightly welded, the shear elastic wave can transmit energy to the heat exchange tube through the tube plate, so that the heat exchange tube also generates shear elastic waves, thereby having the functions and effects of scale prevention and scale removal. The shear elastic wave generator is arranged on the vibration transmission rod of the plate heat exchanger, and because the heat exchange sheets and the vibration transmission rod of the plate heat exchanger are tightly welded, shear elastic waves can be transmitted to each heat exchange sheet through the vibration transmission rod, so that the heat exchange sheets also generate shear elastic waves, and the scale prevention and removal function and effect are achieved.

It should be understood by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be used as a limitation of the present invention, and that the changes and modifications of the above embodiments are within the scope of the claims of the present invention as long as they are within the spirit and scope of the present invention.

Claims (5)

1. An online anti-scale and descaling system with shear elastic waves is characterized by comprising:

the alternating current power supply is used for providing working voltage for the shear elastic wave online scale prevention and removal system;

the rectification filter circuit is used for processing the alternating current into direct current;

an inverter circuit;

the DSP micro-processing system controls the inverter circuit to convert direct current into alternating current pulse signals with time length T, frequency F and voltage V, harmonious response analysis is carried out on the descaled equipment, all vibration mode harmonious response frequency points of the descaled equipment are found, and the inverter circuit is controlled to output alternating current pulses with frequency F and excite the transducer;

the energy converter converts the alternating current pulses with the time length T, the frequency F and the voltage V into mechanical pulse elastic waves with the time length T, the frequency F and the amplitude A, and excites descaled equipment connected with the energy converter to generate a series of pulse harmonic waves;

the harmonic sampling circuit is used for collecting pulse harmonic response points on the descaling equipment and converting the pulse harmonic response points into electric signals;

and the A/D conversion circuit feeds the electric signal converted by the harmonic sampling circuit back to the DSP micro-processing system.

2. The shear elastic wave online antiscaling and descaling system according to claim 1, wherein the mechanical pulse elastic wave has a working frequency of 10kHz to 35kHz and a pulse working time of not less than 10 ms.

3. The shear elastic wave on-line scale prevention and removal system of claim 1, wherein the transducer is made of magnetostrictive material with temperature not lower than 700 ℃ by welding.

4. The shear elastic wave online scale prevention and removal system of claim 1, wherein the transducer is directly or indirectly disposed on the device being removed.

5. An anti-scaling and descaling method adopting a shear elastic wave on-line anti-scaling and descaling system is characterized by comprising the following steps of:

firstly, processing an alternating current 220V power supply into stable direct current through a rectifying and filtering circuit;

step two, the DSP micro-processing system controls the inverter circuit to convert the direct current into alternating current pulse signals with variable time length T, frequency F and voltage V;

step three, exciting the transducer by the alternating current pulse signal, converting the alternating current pulse with the time length T, the frequency F and the voltage V into mechanical pulse elastic waves with the time length T, the frequency F and the amplitude A, and generating a series of pulse harmonic waves after the descaling equipment is excited by the mechanical elastic pulse waves;

step four, converting the pulse harmonic response point on the descaled equipment into an electric signal by a harmonic sampling circuit;

feeding the electric signal converted by the harmonic sampling circuit back to the DSP micro-processing system by the A/D conversion circuit;

and sixthly, the DSP micro-processing system performs harmonic response analysis on the descaled equipment, finds all vibration mode harmonic response frequency points of the descaled equipment, and controls the frequency F of the alternating current electric pulse output by the inverter circuit to excite the transducer.

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