CN108525489B - Coal-fired power plant flue ammonium bisulfate cleaning device based on eddy heating and gas suction method - Google Patents
Coal-fired power plant flue ammonium bisulfate cleaning device based on eddy heating and gas suction method Download PDFInfo
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Abstract
The invention discloses a coal-fired power plant flue ammonium bisulfate cleaning device based on an eddy current heating and gas suction method, which utilizes the solubility and strong conductivity of ammonium bisulfate in water, adopts an eddy current to heat the ammonium bisulfate, accelerates the dissolution of the ammonium bisulfate and uses a gas-water dual-purpose pump to suck the ammonium bisulfate out; the cleaning device comprises a ceramic cylinder, a water feeding channel is arranged on the inner wall of the ceramic cylinder, a distance sensor is fixed at one end of the outer wall of the ceramic cylinder, and a heat-insulating ceramic cylinder is fixedly arranged in the inner cavity of the ceramic cylinder; one end of the heat insulation ceramic cylinder is wound with an induction coil, and the other end of the heat insulation ceramic cylinder is connected with a water/gas dual-purpose pump through a guide pipe; one end of the water pump is connected with a water delivery channel on the inner wall of the ceramic cylinder through a guide pipe; after the ceramic cylinder, the heat insulation ceramic cylinder, the induction coil, the water pump, the water/gas dual-purpose pump and the distance sensor are fixedly installed, the ceramic cylinder, the heat insulation ceramic cylinder, the induction coil, the water pump, the water/gas dual-purpose pump and the distance sensor are fixedly installed on the working platform surface of the displacement control platform through the fastening device. The method can realize the cleaning of the ammonium bisulfate in the flue of the coal-fired power plant, has high cleaning efficiency, thorough cleaning without residue, and is environment-friendly and economical.
Description
Technical Field
The invention belongs to the fields of instrument science and technology, control science, material science, thermology, power systems, boilers and applied chemistry, and particularly relates to a coal-fired power plant flue ammonium bisulfate cleaning device based on an eddy current heating and gas suction method.
Background
In the rapid development process of economy in China, an energy consumption structure mainly based on coal resources is formed, thermal power generation is a main component in a power plant in China, and even if new energy is rapidly developed for more than ten years, thermal power still accounts for more than 60% of the total power generation amount in China at present. Thermal power plant mainly relies on coal-fired electricity generation, at the burning coal in-process, can produce a large amount of smoke and dust, carbon dioxide, sulfur dioxide etc. and these emissions can lead to atmospheric pollution phenomena such as haze, weather warm, acid rain, have caused huge threat to human life health. Since the last 70 s, developed countries have begun to research methods for desulfurizing industrial flue gas, and in recent years, with the gradual and prominent environmental pollution caused by the rapid development of our country's economy, our government has begun to increase the prevention and treatment of environmental pollution, and methods for desulfurizing and denitrating industrial flue gas have also begun to be enriched.
The flue gas control technology of the coal-fired boiler is divided into two categories of combustion control and flue gas desulfurization and denitration, and the basic principle of the combustion control is to form reducing atmosphere in a pulverized coal combustion area to reduce NOxThe amount of production of (c); the flue gas desulfurization and denitration technology is generally to firstly select the flue gas denitration technology to eliminate NOx in the flue gas and then adopt a limestone-gypsum method to purify SO in the flue gas2Flue gas denitration technologies are mainly divided into two types, namely SNCR (selective non-catalytic reduction) and SCR (selective catalytic reduction). The SNCR principle is to use NH3With NO in the flue gasxThe reduction reaction is carried out at high temperature, and the SCR makes NH under the action of a catalyst3With NO in the flue gasxThe reduction reaction occurs at low temperature. The SNCR has the defects of low denitration efficiency, narrow reaction temperature window and the like, is not frequently applied in practice, and the SCR is the only denitration technology for large-scale commercial popularization in the current coal-fired power plant and mainly has the following advantages:
the desulfurization efficiency is high, and the SCR is subjected to gas-gas reaction by flue gas and ammonia gas, so that the contact area of the SCR and the ammonia gas is large, and the reaction efficiency can reach more than 90%;
the device is simple, the SCR equipment only comprises an absorption tower, an oxidation tank, a draught fan and the like, and the operation and maintenance are simple;
the by-product has economic value, and the ammonium sulfate obtained by the SCR technology can be used as a fertilizer, thereby having economic value and reducing the pollution to the environment.
The principle of the SCR method is that a reducing agent (such as ammonia gas, urea and the like) is sprayed into a tail flue (positioned above an SCR catalyst) through an ammonia spraying grid, and NOx in flue gas is converted into water and nitrogen under the action of a vanadium-titanium based catalyst. The ammonia gas is usually prepared by urea pyrolysis or urea hydrolysis, and then is diluted by air and introduced into the flue gas of the tail flue. In the SCR reactor, NOx (main package)Including NO and NO2) The main reaction with ammonia is shown in formulas (1) to (4):
4NH3+4NO+O2＝6H2O+4N2(1)
4NH3+6NO＝6H2O+5N2(2)
4NH3+2NO2+O2＝6H2O+3N2(3)
8NH3+6NO2＝12H2O+7N2(4)
SCR can realize higher oxynitride removal efficiency, but in ammonia gas introduced into a tail flue, a part of the ammonia gas cannot react with flue gas to escape outwards, and meanwhile, in the denitration process, part of SO in the flue gas2Can generate SO under the catalytic action of the active ingredients of the catalyst3Escaped ammonia gas and SO3Carrying out chemical reaction to generate Ammonium Sulfate (AS) and Ammonium Bisulfate (ABS), wherein the chemical formulas are (5) to (6):
2NH3+H2O+SO3＝(NH4)2SO4(5)
NH3+H2O+SO3＝NH4HSO4(6)
many researches show that in the desulfurization and denitrification process of the SCR method, the generation rate of ABS is much higher than AS, in the actual operation of a coal-fired power plant, the generation amount of ABS is also much higher than AS, and the physical properties of ammonium bisulfate are shown in Table 1:
TABLE 1 physical Properties of ammonium bisulfate
Ammonium bisulfate has extremely strong stickness after melting, and the solution has certain acidity and hygroscopicity, therefore ammonium bisulfate is very extensive to the harm that power plant's boiler operation caused, not only has harm to the SCR catalyst, still has important influence to air heater's operation and boiler particulate matter discharge simultaneously. The most serious harm is the formation of blockage, the property of the fly ash can be changed by ammonium bisulfate, the particle size of the fly ash is increased, the hygroscopicity of the fly ash is increased along with the increase of the ammonium bisulfate, and the adhesiveness is improved. When flying ash content is less in the flue gas, the ash grain can only adsorb partial ammonium bisulfate liquid drop, along with the increase of ash content, ammonium bisulfate can adsorb on the ash grain completely, and the stickness of ash grain increases by a wide margin this moment, easily bonds on air heater surface, leads to blockking up.
In practical application of coal-fired power plants, a hot water flushing method is often adopted to solve the problem of blockage, and the method comprises an on-line flushing method and a shutdown flushing method. Because the ammonium bisulfate has high viscosity and is firmly adsorbed on the original piece, the online washing can only wash away the deposited dust on the surface, and the better cleaning effect is difficult to obtain. The coal-fired power plant can also adopt a shutdown flushing scheme in actual operation, after ash on the surface is flushed away by water, ammonium bisulfate is further treated by adopting a method of soaking by using a chemical reagent, but shutdown flushing needs to be carried out according to a scheduling plan, and the power generation efficiency is influenced. In addition, the water washing scheme also has to use a large amount of hot water, consuming a large amount of manpower and material resources. Therefore, the invention has very important significance if the environment-friendly and efficient ammonium bisulfate cleaning device can be invented.
Disclosure of Invention
In order to solve the problems in the existing ammonium bisulfate cleaning technology of a thermal power plant, the invention aims to provide a coal-fired power plant flue ammonium bisulfate cleaning device based on an eddy current heating and gas absorption method. The form of this cleaning device is: a water spraying, heating and air suction device is arranged on a movable workbench, the water spraying device sprays water to the ammonium bisulfate crystals to form a conductive ammonium bisulfate aqueous solution, alternating current is introduced into a heating coil to generate an alternating magnetic field, so that eddy current is formed in the ammonium bisulfate solution, and the ammonium bisulfate is rapidly melted. Due to the skin effect, the temperature of the solution rises rapidly, and simultaneously, the high-power air suction device sucks and discharges ammonium bisulfate, so that the device can clean the working surface rapidly and efficiently; along with the extraction of the surface solution, water is sprayed on the ammonium bisulfate crystal at the lower layer, and the heating and absorbing process is further carried out, so that the thorough cleaning without residue can be ensured; and meanwhile, only a small amount of water is needed, the resource is saved, the environmental protection requirement is met, the discharged ammonium bisulfate can be secondarily processed into the fertilizer, the resource is saved, and the economic benefit is improved.
The invention is realized by adopting the following technical scheme:
a coal-fired power plant flue ammonium bisulfate cleaning device based on a vortex heating and gas suction method comprises a ceramic cylinder, a distance sensor, a water pump, a water/gas dual-purpose pump and a displacement control system; the water supply channel is arranged in the wall of the ceramic cylinder, the heat-insulating ceramic cylinder is fixedly arranged in the ceramic cylinder, an induction coil for heating is sleeved at one end of the heat-insulating ceramic cylinder close to the working surface, a gap is arranged between the inner wall of the ceramic cylinder and the outer wall of the heat-insulating ceramic cylinder, and heat-insulating materials are filled in the gap; the distance sensor is arranged at one end of the ceramic cylinder close to the working surface; one end of the water pump is connected with a water feeding channel in the pipe wall of the ceramic cylinder through a first guide pipe, the other end of the water pump is connected with a water source, and the water pump is used for spraying water to a working surface; one end of the water/gas dual-purpose pump is connected with the heat-insulating ceramic cylinder through a second conduit, the other end of the water/gas dual-purpose pump is arranged in the recovery device, and the water/gas dual-purpose pump is used for pumping the solution discharged from the working surface; the displacement control system comprises a base, a supporting structure, a guide rail and a working table top, wherein the supporting structure, the guide rail and the working table top are sequentially arranged on the base from bottom to top and are used for adjusting the distance between the cleaning device and the working table.
The invention is further improved in that the ceramic cylinder heat insulation material is used for heat insulation of the ceramic cylinder heat insulation ceramic cylinder.
The invention has the further improvement that the outer surface of the whole body of the heat-insulating ceramic cylinder and the induction coil is coated with an outer shell, and the inner side of the side wall of the outer shell is provided with an opening for connecting the induction coil and a variable frequency power supply lead.
The invention is further improved in that the water pump further comprises a microprocessor for controlling the operation of the water pump.
The invention is further improved in that the distance sensor is an ultrasonic distance sensor or an infrared distance sensor, the distance sensor is arranged at the lower part of the ceramic cylinder and is aligned with one end of the ceramic cylinder close to the working surface, the distance sensor is fixedly connected with the ceramic cylinder, and the distance sensor is also connected with the microprocessor.
The invention has the further improvement that the two ends of the ceramic cylinder and the heat insulation ceramic cylinder are fixedly connected through a connecting structure, and the connecting structure is made of heat-resistant materials.
The invention is further improved in that the ceramic cylinder is arranged on the working table and is connected through two fastening rings, and the two fastening rings are respectively arranged in the length directions 1/4 and 3/4 of the ceramic cylinder.
The invention has the further improvement that the joints of the first conduit and the ceramic cylinder and the joints of the first conduit and the water pump are sealed by waterproof sealant, the joints of the second conduit and the heat-insulating ceramic cylinder and the joints of the second conduit and the water/gas dual-purpose pump are sealed by corrosion-resistant and high-temperature-resistant sealant, and the heat-insulating material is wound outside the second conduit.
The invention is further improved in that the heat insulating material between the inner wall of the ceramic cylinder and the outer wall of the heat insulating ceramic cylinder adopts composite silicate.
The invention has the further improvement that the working process is as follows: the vortex air suction device is close to the working surface, and the distance sensor measuring system and the displacement control system measure and adjust the distance between the cleaning device and the working surface, so that water sprayed by the water pump just reaches the working surface;
ammonium sulfate deposited on the working surface and ammonium bisulfate form an ammonium bisulfate solution to become a conductor, a strong alternating magnetic field is generated in the induction coil, the alternating magnetic field forms eddy currents in the ammonium bisulfate solution, the temperature of the ammonium bisulfate solution rises, and due to skin effect, the temperature of the solution close to the ceramic cylinder on the working surface rises to accelerate the dissolution of the ammonium bisulfate;
and after the working surface forms liquid, the water/gas dual-purpose pump forms negative pressure on the working surface, and the ammonium bisulfate solution is extracted and discharged into the recovery device through the second conduit.
The invention has the following beneficial technical effects:
the coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas suction method is provided with the ceramic cylinder, the inner cavity of the ceramic cylinder is provided with the heat-insulating ceramic cylinder, one end of the heat-insulating ceramic cylinder, which is close to the working surface, is wound with the heating coil, and the pipe wall of the ceramic cylinder is provided with the water feeding channel. The ammonium bisulfate sprayed on the working surface through the water feeding channel is water-soluble, and due to the characteristic that the ammonium bisulfate is easy to dissolve in water (1: 1 at 20 ℃), an ammonium bisulfate aqueous solution is quickly formed on the surface of an ammonium bisulfate accumulation layer, the ammonium bisulfate aqueous solution has conductivity, an alternating magnetic field generated by a heating coil wound on the heat-insulating ceramic tube under the action of a power supply generates an eddy effect in the aqueous solution, the temperature of the aqueous solution is quickly increased, and the solubility of the ammonium bisulfate in water is increased. After the temperature exceeds 100 ℃, water starts to vaporize, simultaneously, ammonium bisulfate crystals start to liquefy and soften, and a softened three-phase mixture of ammonium bisulfate, an ammonium bisulfate aqueous solution and water vapor is formed on a working surface. After the temperature exceeds 145 ℃, the ammonium bisulfate crystal begins to liquefy, because the strong electric conductivity of liquid ammonium bisulfate, the electric conductivity of solution has further been strengthened, the vortex effect is strengthened, the temperature rise speed is accelerated, simultaneously high-power gas-liquid dual-purpose pump draws the air to the one end of keeping away from the working face, form very strong negative pressure on the mixture surface of working face, the mixture is absorbed to thermal-insulated ceramic pipe inner chamber under the negative pressure effect, because the strong electric conductivity of mixture, the inside magnetic field of thermal-insulated ceramic pipe continues to heat the mixture, the ammonium bisulfate solid that softens in the mixture further liquefies, the adhesiveness of mixture has been reduced, under the effect of gas/liquid dual-purpose pump, the mixture outwards flows along the pipe. With the loss of the liquid on the surface of the working surface, the process of heating and extracting the aqueous solution is repeated. Because the invention adopts the electric conductor formed between the solid ammonium bisulfate and the dissolving interface and heats the ammonium bisulfate by the eddy current formed in the electric conductor by the alternating magnetic field, compared with the traditional conduction heating, the eddy current heating temperature rises very fast, so the device has the characteristics of fast heating speed, fast extraction speed, fast cleaning and high efficiency.
When alternating current is introduced into a heating coil wound on the heat insulation ceramic cylinder, the coil generates an alternating magnetic field. Because the aqueous solution on the working surface is a current conductor, the liquid conductor in the middle of the heating coil can be equivalent to a closed circuit of one circle in the circumferential direction, and due to the action of an alternating magnetic field, the magnetic flux in the closed circuit is changed continuously, so that induced electromotive force can be generated in the circumferential direction of the liquid conductor, induced current can be generated in the liquid conductor by the induced electromotive force, the direction of the current is rotated along the circumferential direction of the conductor, and the current is called eddy current. The eddy current inside the liquid conductor generates heat, and the longer the outer circumference of the conductor, the higher the frequency of the alternating magnetic field, and the smaller the electrical resistivity of the conductor, the stronger the eddy current, and the higher the amount of heat generated. In the invention, because the aqueous solution of ammonium bisulfate and the liquid ammonium bisulfate are both in strong conductivity, and under the action of a strong alternating magnetic field, the solution can generate very high temperature, so the device can ensure that ammonium bisulfate crystals on the working surface are completely liquefied and extracted and discharged, and has the characteristic of thorough cleaning without residues.
The core of the flow and displacement control system of the device is a microprocessor circuit and a program. Since the throw distance of the water is dependent on the flow rate of water through the pump in the apparatus, a functional relationship between the throw distance of the water and the flow rate can be calculated, the function being stored in the microprocessor with the flow rate of the water as an independent variable and the throw distance as a dependent variable. When the cleaning device is used, the flow rate of the water pump is set, the set flow rate value is transmitted to the microprocessor, the microprocessor calls a distance and flow rate function to calculate, the distance that water is just sprayed to work at the flow rate is obtained, the distance measuring system measures the distance between the current device and a working surface and transmits the distance to the microprocessor, the microprocessor compares the calculated distance value with the measured distance value, the cleaning device is moved to the optimal working distance through the displacement control system, at the moment, water is sprayed on the working surface to form the hydrogen sulfate ammonia water solution, sputtering cannot occur due to the close distance, the hydrogen sulfate ammonia water solution cannot reach the working surface due to the long distance, and only a small amount of water is needed during working, so that the cleaning device can save water resources and ensure the cleaning effect.
Drawings
FIG. 1 is a block diagram of the structure of a coal-fired power plant flue ammonium bisulfate cleaning device based on a vortex heating and gas suction method;
FIG. 2 is a schematic structural view of an ammonium bisulfate cleaning apparatus according to the present invention;
FIG. 3 is a block diagram of displacement and flow control according to the present invention.
The device comprises a ceramic cylinder 1, a heat insulation ceramic cylinder 2, a heating coil 3, a water pump 4, a water/gas dual-purpose pump 5, a distance sensor 6, a base 7, a worktable 7, a guide rail 2, a support structure 7, a first guide pipe 8, a second guide pipe 8, a connecting structure 9, a fastening ring 10, a heat insulation material 11, an ammonium bisulfate solution 12, a working surface 13 and an outer shell 14.
Detailed Description
The invention is described in further detail below with reference to the drawings and the embodiments given by the inventor.
As shown in figures 1 and 2, the device for cleaning ammonium bisulfate in a flue of a coal-fired power plant based on a vortex heating and gas suction method provided by the invention utilizes the solubility and conductivity of ammonium bisulfate in water, sprays water on the surface of the ammonium bisulfate, heats the ammonium bisulfate by adopting a vortex, thereby changes the ammonium bisulfate into fluid, and sucks the fluid by gas suction, thereby realizing the removal of the ammonium bisulfate covered on the surface of an object, the device comprises a ceramic cylinder 1, a water feeding channel is arranged in the pipe wall of the ceramic cylinder 1, a heat insulation ceramic cylinder 2 is fixedly arranged in the ceramic cylinder 1, one end of the heat insulation ceramic cylinder 2 is sleeved with a heating coil 3 for heating, a gap is arranged between the inner wall of the ceramic cylinder 1 and the outer wall of the heat insulation ceramic cylinder 2, a heat insulation material 11 is filled in the gap, the ceramic cylinder 1 and two ends of the heat insulation ceramic cylinder 2 are fixedly connected by a connecting. A water feeding channel in the pipe wall of the ceramic cylinder 1 is connected with one end of a water pump 4 through a first guide pipe 8, the other end of the water pump 4 is connected with a water source, and the water pump 4 is used for spraying water to a working surface. One end of the heat insulation ceramic cylinder 2 is connected with the water/gas dual-purpose pump 5 through a second conduit 8-1, the other end of the water/gas dual-purpose pump 5 is arranged in the recovery device through the second conduit 8-1, and the water/gas dual-purpose pump 5 is used for pumping and discharging liquid solution on the working surface 13. The heating coil 3 is wound at one end of the heat insulation ceramic cylinder 2 close to the working surface 13, the diameter of the heating coil 3 is smaller than the gap between the outer wall of the heat insulation ceramic cylinder 2 and the ceramic cylinder 1, and the heating coil 3 is covered with a heat insulation material 11 and a waterproof coating. The joint of the first conduit 8 and the ceramic cylinder 1 and the joint of the first conduit 8 and the water pump 4 are sealed by waterproof sealant, the joint of the second conduit 8-1 and the heat-insulating ceramic cylinder 2 and the joint of the second conduit 8-1 and the water/gas dual-purpose pump 5 are sealed by corrosion-resistant and high-temperature-resistant sealant, the heat-insulating material covering the heating coil 3 is rare earth heat-insulating coating, and the heat-insulating material 11 between the inner wall of the ceramic cylinder 1 and the outer wall of the heat-insulating ceramic cylinder 2 is composite silicate. The outer surface of the heat insulation ceramic cylinder 2 and the heating coil 3 are integrally coated with an outer shell 14, and the inner side of the side wall of the outer shell 14 is provided with an opening for connecting the heating coil 3 and a variable frequency power supply wire.
In addition, still include distance sensor 6, distance sensor 6 is ultrasonic wave distance sensor or infrared distance sensor, and distance sensor installs in ceramic section of thick bamboo 1 lower part, aligns with the one end that ceramic section of thick bamboo 1 is close to the working face, and distance sensor 6 passes through clamping ring fixed connection with ceramic section of thick bamboo 1.
The device is characterized by further comprising a displacement control system, wherein the displacement control system comprises a base 7, a working table surface 7-1, a supporting structure 7-3, a guide rail 7-2, an air suction system, a vortex heating system, a water supply system and a distance sensor which are fixedly connected and then arranged on the working table surface 7-1 and connected through two fastening rings 10, the two fastening rings are respectively arranged at 1/4 and 3/4 in the length direction of the ceramic cylinder 1, and the displacement control system is used for adjusting the distance between the cleaning device and the working surface to keep the distance within a reasonable range.
With reference to fig. 3, the operation process of the coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas absorption method provided by the invention is as follows:
after the cleaning device has approached the work surface to be cleaned, the distance sensor 6 measures the distance S between the work surface and the device1The micro-processor receives the flow of the water pump 4 and calculates the optimal distance S between the working device and the working surface at the flow2The microprocessor calculates the difference between the two distances, Δ S ═ S1-S2If the delta S is larger than zero, the distance between the cleaning device and the working surface is larger than the optimal distance, the microprocessor sends a control instruction to the displacement control system, the displacement control system controls the working surface 7-1 to move towards the direction close to the working surface to be cleaned along the guide rail 7-2, the moving distance is delta S, if the delta S is smaller than zero, the distance between the cleaning device and the working surface is smaller than the optimal distance, the microprocessor sends a control instruction to the displacement control system, the displacement control system controls the working surface 7-1 to move towards the direction far away from the working surface to be cleaned along the guide rail 7-2, the moving distance is delta S, and the water pumped by the water pump 4 at the moment is just sprayed to the working surface to be cleaned through the first guide pipe 8 and the water feeding channel on the inner wall of the ceramic cylinder 1.
After the displacement control system controls the cleaning device to move to the optimal position, ammonium bisulfate crystals accumulated on a working surface to be cleaned are dissolved in water sprayed by a water supply system, a layer of ammonium bisulfate aqueous solution is formed on the surface to be cleaned, meanwhile, a variable frequency power supply supplies power to the heating coil 3, a strong alternating magnetic field is generated around the heating coil 3, the magnetic field generates vortex in the aqueous solution, under the action of the vortex effect, the temperature of the aqueous solution is rapidly increased, the ammonium bisulfate crystals at the lower layer of the aqueous solution begin to liquefy, and a mixed solution of the ammonium bisulfate aqueous solution and liquid ammonium bisulfate is formed on the surface of the working surface. Meanwhile, the water/gas dual-purpose pump pumps gas outwards through the second guide pipe 8-1 and the inner cavity of the heat insulation ceramic cylinder 2, strong negative pressure is formed on the surface of the mixed liquid on the working surface, and the mixed liquid is discharged to a collecting device along the inner cavity of the heat insulation ceramic cylinder 2 and the second guide pipe 8-1 under the action of the negative pressure.
The displacement control system is a closed-loop control system, after the cleaning device is close to the working surface to be cleaned, the microprocessor determines whether the working device is close to the working surface or the principle working surface according to the actual distance value and the calculated optimal displacement value, then the working device is moved to the optimal cleaning position through the displacement control system to start working, and in the process of absorbing and discharging the ammonium bisulfate, the distance between the working device and the working surface is increased along with the gradual reduction of the thickness of an accumulation layer of the ammonium bisulfate, the microprocessor controls the cleaning device to slowly move towards the direction close to the working surface, so that the relative displacement between the cleaning device and the working surface is unchanged, and the optimal cleaning effect is ensured.
Examples
In this embodiment, the coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas absorption method is mainly composed of a medium-frequency power supply, a ceramic cylinder 1, a heat-insulating ceramic cylinder 2, an ultrasonic or infrared distance sensor, a heating coil 3, a displacement control system, a water pump 4, a water/gas dual-purpose pump 5 and a microprocessor, as shown in fig. 1 and 2.
Microprocessor adopts the singlechip, like STM32F series, microprocessor is used for realizing the displacement control function, and after cleaning device is close to the working face, microprocessor judges whether cleaning device need be close to the working face or keep away from the working face according to the difference delta S of distance sensor measured value and calculated value, and displacement control system removes cleaning device to best working distance after, cleaning device begins to heat and absorbs the accumulational ammonium bisulfate crystal on the discharge working face. During this time, the display device displays the real-time distance between the cleaning apparatus and the work surface. The distance measuring sensor is mainly used for measuring the distance between the cleaning device and the working face, measured distance signals are sent to the microprocessor after being conditioned by the conditioning circuit, the microprocessor performs data processing again, only the condition that water sprayed by the water pump 4 just reaches the working face is met, the model of the distance measuring sensor is not limited, the precision requirement is not high, and the centimeter level can be met. The displacement control system is used for adjusting the distance between the cleaning device and the working surface, and the use requirement can be met when the precision is centimeter level. In the embodiment, the microprocessor adopts STM32F103RBT6, the distance sensor adopts an ultrasonic distance sensor, an ultrasonic distance measuring module with the model of HC-SR04 is selected, the effective measuring range is 2 cm-450 cm, the precision can reach 2mm, the distance measuring requirement is met, the displacement platform adopts a single-shaft high-precision electric displacement platform with the model of PT-GD140G-500, the stroke is 50cm, the size of a table top is 16cm multiplied by 16cm, the platform carries 50kg, the use requirement is met, and the display equipment adopts a 2.4-inch liquid crystal display screen with the size of 380 multiplied by 240;
the working process is realized in three steps, wherein the first step is to form a conductor object heated by eddy current: spraying water to the surface of the ammonium bisulfate crystals accumulated on the working surface through the water pump 4, the first conduit 8 and the channel in the pipe wall of the ceramic cylinder 1 to form a conductive ammonium bisulfate aqueous solution, wherein the aqueous solution is a conductor object heated by the eddy current; secondly, generating an eddy current effect, wherein a variable frequency power supply transmits high-frequency alternating current to a heating coil 3 wound on one end of the heat-insulating ceramic tube 2 close to the working surface through a wire, the high-frequency alternating current in the heating coil 3 generates an alternating magnetic field around the heating coil, a liquid conductor in the magnetic field generates heat due to the eddy current effect, and after the temperature rises to be higher than 145 ℃, the ammonium bisulfate crystal begins to liquefy, so that the resistivity of the liquid conductor is further reduced, the conductivity of the solution is increased, and the eddy current effect is further enhanced; thirdly, discharging ammonium bisulfate crystals by a gas suction method, pumping gas from the water/gas dual-purpose pump to the direction far away from the working surface through the second conduit 8-1 and the heat-insulating ceramic cylinder 2, so that a large negative pressure is formed on the working surface, and under the action of the negative pressure, the ammonium bisulfate solution flows along the inner cavity of the heat-insulating ceramic cylinder 2 and the second conduit 8-1 to the direction far away from the working surface and is finally discharged to a solution collecting device;
the ceramic cylinder 1 is an outer layer structure of the cleaning device and is fixed on a working surface of the displacement control device through the fastening device, so that a material with high hardness and good wear resistance is needed. The heat insulation ceramic cylinder 2 is mainly used for winding the heating coil 2 and providing a solution discharge channel, and in order to prevent ammonia bisulfate solution from being adhered to the inner wall of the heat insulation ceramic cylinder 2 after being cooled in the discharge process to cause blockage and influence the cleaning effect, the heat insulation ceramic cylinder needs to be made of a material with good heat insulation performance, in the implementation, zirconia ceramic is adopted, the heat conductivity is 1.6-2.03W/(m.k), and the use requirement is met. The heat insulation material between the outer wall of the heat insulation ceramic cylinder 2 and the inner wall of the ceramic cylinder 1 mainly plays a role of heat insulation and preservation material, and the material adopts neutral corundum spinel (AL) in consideration of actual requirements2O3MgO) filled with a dry ramming mass, in this example, specifically, tabular corundum (particle size: 0 to 2mm), sintered spinel particles as an aggregate, fused spinel fine powder (0.044 mm or less), white corundum fine powder (0.044 mm or less), α -Al2O3Micro powder (less than or equal to)5 mu m), taking pure calcium aluminate cement as a matrix, and preparing materials according to the mass ratio of the aggregate to the matrix of 70: 30;
the model, the data plate of variable frequency power supply and power electronic switch do not limit, choose for use according to user's actual demand, and the heating coil form is not limited, chooses for use according to user's actual demand, and variable frequency power supply and heating coil all can purchase on market. In the embodiment, a variable frequency power supply with the frequency of 5kHz and the power of 2000W is selected, a heating coil is wound by a copper wire, and a switch adopts a conventional power electronic switch IGBT;
in the using process of the cleaning device, when the cleaning device is close to a working surface to be cleaned, the distance measuring sensor measures and uploads the distance between the cleaning device and the working surface to be cleaned, the microprocessor STM32F103RBT6 receives and stores the measured distance value and displays the measured distance value on a liquid crystal screen of the display device in real time, the water pump 4 uploads the flow value to the microprocessor, the microprocessor obtains the optimal cleaning distance value under the flow through calculation, then the microprocessor compares the distance value measured by the ultrasonic distance sensor with the calculated optimal value, a distance deviation delta S is obtained at the moment, then the microprocessor determines to be far away from or close to the working surface according to the distance deviation delta S, and then controls the displacement platform to move to the optimal distance. After displacement control is completed, a water pump 4 sprays water to ammonium bisulfate crystals accumulated on a working surface through a first conduit 8 and a water feeding channel inside a ceramic cylinder 1 to form a conductive ammonium bisulfate solution, a high-frequency power supply transmits current to a heating coil 3, an alternating magnetic field generated on the heating coil 3 forms vortex in the ammonium bisulfate solution, the temperature of the ammonium bisulfate solution rises under the action of a vortex effect, the ammonium bisulfate solution starts to liquefy after the temperature is higher than 145 ℃, a water/gas dual-purpose pump 5 pumps gas outwards through a second conduit 8-1 and an inner cavity of a heat insulation ceramic cylinder 2 to form strong negative pressure on the surface of the ammonium bisulfate solution, and the ammonium bisulfate solution is discharged to a collecting device along the second conduit 8-1 under the action of the negative pressure.
While the invention has been described in further detail with reference to specific preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A coal-fired power plant flue ammonium bisulfate cleaning device based on a vortex heating and gas suction method is characterized by comprising a ceramic cylinder (1), a distance sensor (6), a water pump (4), a water/gas dual-purpose pump (5) and a displacement control system; wherein, a water feeding channel is arranged in the pipe wall of the ceramic cylinder (1), a heat insulation ceramic cylinder (2) is fixedly arranged in the ceramic cylinder (1), one end of the heat insulation ceramic cylinder (2) close to the working surface (13) is sleeved with an induction coil (3) for heating, a gap is arranged between the inner wall of the ceramic cylinder (1) and the outer wall of the heat insulation ceramic cylinder (2), and a heat insulation material (11) is filled in the gap; the distance sensor (6) is arranged at one end of the ceramic cylinder (1) close to the working surface (13); one end of the water pump (4) is connected with a water feeding channel in the pipe wall of the ceramic cylinder (1) through a first guide pipe (8), the other end of the water pump is connected with a water source, and the water pump (4) is used for spraying water to a working surface (13); one end of the water/gas dual-purpose pump (5) is connected with the heat-insulating ceramic cylinder (2) through a second conduit (8-1), the other end is arranged in the recovery device, and the water/gas dual-purpose pump (5) is used for pumping and discharging the solution on the working surface (13); the displacement control system comprises a base (7), and a support structure (7-3), a guide rail (7-2) and a working table top (7-1) which are sequentially arranged on the base (7) from bottom to top and are used for adjusting the distance between the cleaning device and the working surface (13).
2. The coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas suction method as defined in claim 1, further comprising a variable frequency power supply for supplying power to the induction coil (3), wherein the diameter of the induction coil (3) is smaller than the gap between the outer wall of the heat-insulating ceramic cylinder (2) and the ceramic cylinder (1), the induction coil (3) is covered with a heat-insulating material and a waterproof coating, and the heat-insulating material is rare earth heat-insulating coating.
3. The coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas suction method as defined in claim 2, wherein the outer surface of the whole of the heat-insulating ceramic cylinder (2) and the induction coil (3) is coated with an outer shell (14), and the inner side of the side wall of the outer shell (14) is provided with an opening for connecting the induction coil (3) and a variable frequency power supply lead.
4. The coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas suction method as defined in claim 1, further comprising a microprocessor for controlling the operation of the water pump (4).
5. The coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas suction method as defined in claim 4, wherein the distance sensor (6) is an ultrasonic distance sensor or an infrared distance sensor, the distance sensor (6) is installed at the lower part of the ceramic cylinder (1) and is aligned with one end of the ceramic cylinder (1) close to the working surface (13), the distance sensor (6) is fixedly connected with the ceramic cylinder (1), and the distance sensor (6) is further connected with the microprocessor.
6. The coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas suction method as defined in claim 5, wherein the ceramic cylinder (1) is fixedly connected with the two ends of the heat-insulating ceramic cylinder (2) through connecting structures (9), and the connecting structures (9) are made of heat-resistant materials.
7. The coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas suction method as defined in claim 1, wherein the ceramic cylinder (1) is placed on a working table (7-1) and connected by two fastening rings (10), and the two fastening rings (10) are respectively placed at 1/4 and 3/4 in the length direction of the ceramic cylinder (1).
8. The coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas suction method as defined in claim 1, wherein the joints of the first conduit (8) and the ceramic cylinder (1) and the joints of the first conduit (8) and the water pump (4) are sealed by waterproof sealant, the joints of the second conduit (8-1) and the heat-insulating ceramic cylinder (2) and the joints of the second conduit (8-1) and the water/gas dual-purpose pump are sealed by corrosion-resistant and high-temperature-resistant sealant, and a heat-insulating material is wound outside the second conduit (8-1).
9. The coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas suction method as defined in claim 1, wherein the heat insulating material between the inner wall of the ceramic cylinder (1) and the outer wall of the heat insulating ceramic cylinder (2) is composite silicate.
10. The coal-fired power plant flue ammonium bisulfate cleaning device based on the eddy current heating and gas suction method as claimed in claim 1, wherein the working process is as follows: the vortex air suction device is close to the working surface (13), the distance sensor measuring system and the displacement control system measure and adjust the distance between the cleaning device and the working surface (13), so that water sprayed by the water pump (4) just reaches the working surface (13);
ammonium sulfate deposited on the working surface (13) and ammonium bisulfate form an ammonium bisulfate solution (12) to become a conductor, a strong alternating magnetic field is generated in the induction coil (3), the alternating magnetic field forms eddy current in the ammonium bisulfate solution (12), the temperature of the ammonium bisulfate solution (12) rises, and the temperature of the solution on the working surface (13) close to the ceramic cylinder (1) rises due to skin effect to accelerate the dissolution of the ammonium bisulfate;
after the working surface (13) forms liquid, the water/gas dual-purpose pump (5) forms negative pressure on the working surface (13), and the ammonium bisulfate solution (12) is extracted and discharged to a recovery device through a second conduit (8-1).
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