CN110174020A - A kind of heat exchanger of unsymmetrical arrangement - Google Patents

Abstract

The present invention provides an asymmetrically arranged heat exchanger. The heat exchanger includes a header, and left and right coils are distributed on the left and right sides of the header. It is characterized in that the left coil and the right The coils are arranged at intervals, a right coil is arranged between two adjacent left coils, and a left coil is arranged between two adjacent right coils. The heat exchanger designed in the present invention can enhance heat exchange and dust removal at different heights, and enhance the effects of heat exchange and dust removal.

Description

An asymmetrically arranged heat exchanger

technical field

The invention belongs to the technical fields of heat exchange technology and flue gas desulfurization, and in particular relates to an asymmetrically arranged heat exchanger and a flue gas waste heat utilization system thereof.

Background technique

my country is the world's largest coal producer and consumer. Coal-fired power plants consume a lot of coal to provide steam and electricity, but also emit a lot of waste heat. Flue gas waste heat recovery generally adopts shell-and-tube heat exchangers, so the enhanced heat transfer technology of heat exchangers is of great significance to energy saving and consumption reduction. Among them, passive enhanced heat transfer technology has become an important research direction because it does not require external high-quality energy input to achieve the purpose of enhanced heat transfer.

The use of fluid-induced vibration of heat transfer elements to achieve enhanced heat transfer is a form of passive enhanced heat transfer, which can transform the strict prevention of fluid vibration induction in the heat exchanger into the effective use of vibration, so that the transmission elements can operate at low flow rates The convective heat transfer coefficient is greatly improved, and the vibration is used to suppress the dirt on the surface of the heat transfer element, reduce the thermal resistance of the dirt, and realize the compound enhanced heat transfer.

In addition, while coal-fired power plants consume a large amount of coal, they also emit a large amount of pollutants such as SO ₂ . Flue gas desulfurization is one of the effective technologies for reducing flue gas SO ₂ emissions, including wet, dry, and semi-dry desulfurization technologies. Among them, wet desulfurization, especially limestone/gypsum wet desulfurization, is the most widely used, but this method consumes Large amount of water, difficult wastewater treatment, large investment and other problems, and most of the desulfurization by-product gypsum is left idle, which not only occupies land resources but also causes secondary pollution; while the dry and semi-dry desulfurization processes are simple, but there are high Ca/S ratios, Low desulfurization efficiency, high desulfurization agent regeneration and replacement costs, etc., so finding alternative environmentally friendly desulfurizers has become an important issue that needs to be solved urgently.

Ionic liquids are a class of organic molten salts composed of anions and cations that are liquid at or near room temperature. They have extremely low volatility, wide electrochemical windows, and good selective dissolution or absorption/attachment properties. Studies have shown that ionic liquids have good selective dissolution and absorption/adsorption effects on SO ₂ . The advantage of ionic liquid desulfurization technology is that it can remove SO ₂ cost-effectively and without secondary pollution, and turn it into a usable Chemical raw materials, and the absorbent can be regenerated and recycled. However, due to the inherent high viscosity of the ionic liquid and the large gas mass transfer resistance, the application of the absorbent as an absorbent in gas-liquid separation is unfavorable, resulting in the carry loss of the ionic liquid. At the same time, for the desorption and regeneration of ionic liquid desulfurization agent, an additional heat source is required to provide energy, which also increases the desulfurization operation cost to a certain extent.

In the utilization of flue gas waste heat, the structure of the heat exchanger is also a very important design, especially a heat exchanger that prevents dust collection is very important.

In view of the above problems, the present invention provides a new flue gas waste heat utilization heat exchanger and a waste heat utilization method, which can make full use of heat sources, reduce energy consumption, and realize resource efficient desulfurization at the same time.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a heat exchanger utilizing waste heat of flue gas to enhance heat exchange and remove ash.

To achieve the above object, the present invention adopts the following technical solutions:

An asymmetrically arranged heat exchanger, the heat exchanger includes a header, the left and right coils are distributed on the left and right sides of the header, and it is characterized in that the left coil and the right coil are arranged at intervals , a right coil is arranged between two adjacent left coils, and a left coil is arranged between two adjacent right coils.

Preferably, a left pipe and a right pipe are included as headers of the left coil and the right coil.

A flue gas waste heat utilization system, including an air preheater, a first heat exchanger, a second heat exchanger, a first absorption/desorption tower, a second absorption/desorption tower, a gas-solid separator, a fan, and a gas storage system Acid plant, compressor and chimney, the air preheater is connected to the heat exchanger, and the flue gas cooled by the air preheater enters the first heat exchanger for secondary heat exchange with the air in the heat exchanger, after heating The air is returned to the air preheater for secondary reheating; the first heat exchanger is also used as a heater for starting the nitrogen in the analysis system, and the heated nitrogen is connected to the absorption/analysis tower through pipelines; the second heat exchange The flue gas side of the device is connected to the absorption/desorption tower, the upper part of the absorption/desorption tower is connected to the chimney through the pipeline, the bottom of the absorption/desorption tower is connected to the gas-solid separator through the pipeline, and the gas-solid separator is connected to the fan and the compressor in turn. The compressor is respectively connected to the gas storage and acid production device and the second heat exchanger through pipelines.

Preferably, the air enters the air preheater after exchanging heat with the heat source from the compressor in the second heat exchanger for further heat exchange before being utilized.

Preferably, a dust collector is arranged on the flue gas pipeline between the air preheater and the heat exchanger.

As a preference, the absorption/desorption tower is two devices in parallel structure, which are switched by setting valves on the inlet and outlet flue gas pipelines.

As preferably, the activated carbon after loading the ionic liquid is carried out absorption reaction with SO2 in the first absorption/analysis tower, and when the absorption reaches saturation, the flue gas switches into the _second absorption/analysis tower for adsorption; the first absorption/analysis tower starts Desorption, in this way, the two reaction towers are recycled.

As a preference, the flue gas first passes through the air preheater for preliminary cooling, then passes through the dust collector, enters the heat exchanger to exchange heat with the air, and after the flue gas temperature drops below 50°C, the flue gas enters the absorption tower for adsorption, and the flue gas is purified. from the chimney;

As a preference, the system is equipped with start-up nitrogen, which is only used for the start-up process of the desorption tower. Start the nitrogen gas to exchange heat with the flue gas through the heat exchanger. The heated nitrogen gas enters the saturated reaction tower as desorption gas for desorption. The desorbed mixed gas passes through the gas-solid separator to separate the gas from the solid particles. _The blower draws the desorbed mixture into the compressor to separate _N2 from SO2. The separated SO ₂ enters the gas storage tank/acid system to realize the resource utilization of SO ₂ ; the N ₂ carries the heat released by the compression of the compressor, and passes through the second heat exchanger to reduce the temperature to about 100°C and enters the desorption tower. Recycling.

The heat exchange medium in the second heat exchanger is air, and the air directly enters the air preheater after exchanging heat with the desorbed gas through the second heat exchanger, so as to meet the hot air required in the boiler.

Advantage and effect of the present invention are:

1) The heat exchanger designed in the present invention can enhance heat exchange and dust removal at different heights, and enhance the effect of heat exchange and dust removal.

2) The flue gas waste heat utilization system designed in the present invention can make full use of the flue gas waste heat and achieve the effect of reducing emissions.

3) After desulfurization, recovery of waste heat auxiliary regeneration system makes full use of the heat of flue gas at the tail, so that the regeneration of desulfurizer fully relies on the heat flow in the system, which solves the problem of difficult utilization of low-temperature flue gas at the tail, and converts SO ₂ into gas Or the way of sulfuric acid was collected.

4) The present invention loads the ionic liquid on the surface of porous activated carbon, which not only has the characteristics of a solid phase carrier such as large surface area, high porosity and good mechanical strength, but also has the characteristics of an ionic liquid phase that is difficult to volatilize and has good gas solubility. Liquid particles have a faster rate of gas absorption.

5) The present invention uses activated carbon as the adsorption carrier, which is light in weight, strong in stability and economical.

6) The present invention proposes a vibrating symmetrical heat exchange tube bundle with a new structure. By arranging more coils in a limited space, the vibration range of the pulsating tube bundle is increased, thereby enhancing heat transfer and descaling.

7) This application automatically adjusts the pulsating flow rate of each tube bundle through the average heat transfer, so as to achieve uniform heat transfer as a whole and enhance the heat transfer effect.

Description of drawings:

Fig. 1 is a schematic structural diagram of the waste heat utilization system of the present invention;

Fig. 2 is a schematic top view of the vibrating tube bundle structure of the present invention.

Fig. 3 is a schematic top view of another structure of the vibrating tube bundle of the present invention.

Fig. 4 is a schematic diagram of the vibrating tube bundle of the present invention.

Fig. 5 is another structural diagram of the vibrating tube bundle of the present invention.

Fig. 6 is a schematic diagram of a heat exchanger with a built-in vibrating tube bundle of the present invention.

In the figure: 1. Air preheater; 2. Dust collector 3. First heat exchanger; 4. First absorption/desorption tower; 5. Second absorption/desorption tower; 6. Gas-solid separator; Compressor fan; 8. Gas storage/acid plant; 9. Compressor; 10. Chimney; 11. Second heat exchanger; 12. Vibrating coil; 121 left coil, 122 right coil, 123 left standpipe, 124 right standpipe, middle standpipe 125, free end 13-14, heat exchange pipe 15, flue gas inlet 16, flue gas outlet 17.

Detailed ways

As shown in the figure, a flue gas waste heat utilization system and a carbon-based loaded ionic liquid flue gas desulfurization method include an air preheater 1, a first heat exchanger 3, a first absorption/desorption tower 4, a fan 6, and a gas storage An acid plant 8, a compressor 9 and a chimney 8, the air preheater 1 is connected to the first heat exchanger 3, and the flue gas from the air preheater 1 enters the first heat exchanger 3 and the first heat exchanger 3 The air in the air is heat exchanged. The air heated from the first heat exchanger 3 enters the air preheater 1 through the air pipeline, and continues to exchange heat with the flue gas in the air preheater. The air after heat exchange Hot air is formed, preferably hot primary air enters the furnace to support combustion. The side of the flue gas cooled by the first heat exchanger 3 is connected to the first absorption/analysis tower 4, and the bottom of the first absorption/analysis tower 4 is connected to the compressor 9 through a pipeline, between the first absorption/analysis tower 4 and the compressor 9 The fan 7 is arranged on the pipeline between them, and the upper part of the first absorption/desorption tower 4 is connected with the chimney 10 through a pipeline;

As preferably, also comprise second heat exchanger 11, described second heat exchanger 11 is arranged on the pipeline between compressor 9 and first absorption/desorption tower 4, cold air is in second heat exchanger 11 and The thermally decomposed gas from the compressor enters the air preheater 1 for heat exchange after heat exchange. Preferably the heated air forms hot secondary air.

Preferably, a dust collector 2 is arranged on the flue gas pipeline between the air preheater 1 and the first heat exchanger 3 . Dust removal of the flue gas can be achieved by setting up a dust collector to reduce dust accumulation and scaling.

As a preference, a gas-solid separator 6 is arranged on the pipeline between the first absorption/desorption tower 4 and the fan 7 to realize gas-solid separation.

Preferably, there are two absorption/desorption towers in parallel structure, 4 and 5 respectively, and valves are set on the flue gas pipeline between the heat exchanger 3 and each absorption/desorption tower. Valves are arranged on the pipelines between the second heat exchanger 11 and each absorption/desorption tower 4,5. By setting two absorption/desorption towers and setting valves respectively, the adsorption and regeneration of the absorption/desorption towers can be realized through the opening and closing of the valves.

When the first absorption/desorption tower ₄ is used as the absorption tower, the loaded activated carbon reacts with SO in the absorption tower, and when the first absorption tower reaches saturation, the flue gas enters the second absorption/desorption tower 5 for adsorption; adsorption The saturated first absorption tower starts to desorb, and in this way, the two reaction towers are recycled.

As a preference, the flue gas first passes through the air preheater 1 for preliminary cooling, then passes through the dust collector 2, enters the heat exchanger to exchange heat with the air, and after the flue gas temperature drops below 50°C, the flue gas enters the absorption tower for adsorption, clean Flue gas is discharged from chimney 10;

As a preference, the system is equipped with start-up nitrogen, which is only used for the start-up process of the desorption tower. The nitrogen gas is started to exchange heat with the flue gas through the first heat exchanger 4, and the heated nitrogen gas enters the saturated reaction tower for desorption, and the desorbed mixed gas passes through the gas-solid separator 6 to separate the gas from the solid particles. The booster blower 7 sends the desorbed mixed gas into the compressor ₉ to separate _N2 from SO2. The separated SO ₂ enters the gas storage tank/acid system 8 to realize the resource utilization of SO ₂ ; N ₂ carries the heat released by the compressor, and passes through the second heat exchanger 5 to reduce the temperature to about 100°C and enters the desorption tower , so recycled. The whole system makes full use of the waste heat of the flue gas and the heat released by the compression of the compressor to realize the repeated utilization and resource utilization of the activated carbon-loaded ionic liquid desulfurizer.

Preferably, the vibrating coil 12 is used in the first and second heat exchangers, which can make full use of waste heat and save energy.

_The present invention selects triethanolamine acetate plasma liquid, and this alcohol amine ionic liquid has chemical absorption and physical absorption at the same time when _adsorbing SO. , see the following formula:

The absorbent used in the present invention is to load the ionic liquid with high viscosity on the surface of porous activated carbon through a simple impregnation-evaporation physical loading method, improve the dispersibility of the ionic liquid, increase the reaction specific surface area, and solve the problem that the high viscosity of the ionic liquid is not conducive to transmission. At the same time, the loaded ionic liquid is difficult to volatilize and has good gas solubility. The particles loaded with ionic liquid have a faster gas absorption rate, and the waste heat of the flue gas is used to realize the regeneration of the desulfurizer, which can effectively reduce the operating cost. cost.

As conceived above, the technical solution of the present invention is: first prepare the ionic liquid and load it on porous media such as carbon-based materials, and then perform efficient desulfurization through the reactor, and the absorbent after desulfurization is heated and regenerated in the regeneration device, and the required heat It is mainly provided by waste heat of flue gas and compression heat release of compressor; at the same time, SO ₂ gas is recovered during the regeneration process.

In this technology, the ionic liquid can be low-viscosity ionic liquid or high-viscosity ionic liquid. During the preparation of the ionic liquid, the microwave method can be used to quickly synthesize the target product and shorten the reaction time; in this technology, the carbon-based material is used to load the ionic liquid, carbon The base material can be activated carbon, activated coke, etc., or loaded on porous materials such as silica gel, and loaded by impregnation and evaporation; and the mass ratio of ionic liquid to the loaded material is below 1.5:1.

In this technology, the reactor uses a fixed-bed desulfurizer and adopts a thermal regeneration method. The heat source includes two parts, one is to use the residual heat of the flue gas passing through the inlet of the desulfurization system, and the other is to use the compressor to compress and release heat.

This technology uses carbon-based materials to support ionic liquids, which not only solves the problem that high-concentration ionic liquids are difficult to apply, but also can remove SO ₂ more efficiently through the synergy of carbon-based materials and ionic liquids.

This technology effectively reduces the cost of absorbent regeneration through the utilization of flue gas waste heat, and further improves the economical efficiency of this technology.

Further preferably, the preparation method of the desorption absorption material is as follows:

Example 1: The ionic liquid used was synthesized under the action of microwaves. The ratio of triethanolamine and acetic acid was 1.2:1. After synthesis, activated carbon or silica gel was used for loading by impregnation. The loading ratio was 0.75:1, and then the ionic liquid was realized by evaporation and drying. load;

Example 2: The ionic liquid used was synthesized under the action of microwaves, the ratio of triethanolamine and acetic acid was 1.2:1, and after synthesis, 80-120 mesh activated carbon was used for loading by impregnation. The load ratio is 0.75:1, accurately weigh 7.5g of ionic liquid and dissolve it in 30ml of absolute ethanol, put 10g of 80-100 mesh activated carbon into it, keep stirring and gradually raise the temperature to 90°C, when most of the solvent is evaporated , put the loaded activated carbon into a drying oven at 50°C and dry until particles appear.

Take 2g of loaded activated carbon and place it in the reactor, pass through the simulated flue gas, and carry out the adsorption experiment at 40°C, and the loaded activated carbon is penetrated for about 7 hours.

Example 3: The ionic liquid used was synthesized under the action of microwaves, the ratio of triethanolamine and acetic acid was 1.2:1, and after synthesis, 60-80 mesh was used for loading by impregnation. The loading ratio is 0.75:1. Accurately weigh 7.5g of ionic liquid and dissolve it in 30ml of absolute ethanol. Put 10g of activated carbon into it, stir continuously and gradually raise the temperature to 90°C. When most of the solvent is evaporated, put the loaded The silica gel was dried in a drying oven at 50°C until particles appeared.

Take 2g of loaded activated carbon and place it in the reactor, pass through the simulated flue gas, and conduct the adsorption experiment at 40°C. The adsorption is complete in about 1.5h.

Example 4: Preparation of loaded activated carbon particles with a loading ratio of 1:1. Accurately weigh 10g of ionic liquid and dissolve it in 40ml of absolute ethanol, put 10g of activated carbon into it, stir continuously and gradually raise the temperature to 90°C, when most of the solvent is evaporated, put the loaded silica gel in a drying oven at 50°C Tumble dry until granulated.

Weigh 4g of loaded activated carbon particles (which contains 2g of activated carbon and 2g of ionic liquid) and conduct an adsorption test at 40°C. The adsorption efficiency is above 98% within 160 minutes.

Example 5: Preparation of supported activated carbon particles with a loading ratio of 1.3:1. Accurately weigh 13g of ionic liquid and dissolve it in 52ml of absolute ethanol, put 10g of activated carbon into it, stir continuously and gradually raise the temperature to 90°C, when most of the solvent is evaporated, put the loaded silica gel in a drying oven at 50°C Tumble dry until granulated.

Weighed 4.6g of loaded activated carbon particles (which contained 2g of activated carbon and 2.6g of ionic liquid) for adsorption test at 40°C, and the adsorption efficiency was above 98% within 285 minutes.

Example 6: Accurately weigh 10g of triethanolamine and dissolve it in 30ml of absolute ethanol, put 10g of silica gel in it, stir continuously and gradually raise the temperature to 90°C, when most of the solvent is evaporated, put the loaded silica gel into the drying oven Dry at 50°C until particles appear. Finally, it was shown that the loaded silica particles were white.

Take 2g of loaded silica gel and place it in the reactor, pass through the simulated flue gas, and conduct the adsorption experiment at 40°C. Among them, the adsorption efficiency is above 90% within 440 minutes.

Further preferably, a desulfurizer loaded with ionic liquid is characterized in that it is prepared according to the following process steps:

(1) Weigh 1.2:1 triethanolamine and acetic acid according to the molar ratio and add them to the three-necked microwave special flask and the adjustable dosing device respectively.

(2) Put the three-necked flask into the microwave reactor, and connect the three-necked flask to the adjustable quantitative dosing device equipped with acetic acid, the protective gas guide tube, and the thermowell through the corresponding interface of the microwave reactor. Put half a beaker of clear water into the container, and start the microwave reactor to react.

(3) Pass in the protective gas, and let the acetic acid in the adjustable dosing device be dropped into the three-necked flask within 1/2 of the reaction time; at the same time, adjust the magnetic stirring speed control knob to stir the reactants in the three-necked flask .

(4) After the reaction, the crude product was evaporated with a rotary evaporator to remove part of the unreacted solvent, and then dried to a constant weight at 50°C in a vacuum drying chamber to obtain the purified triethanolamine acetate ionic liquid.

(5) Pretreatment of activated carbon: choose a particle size between 40-100 mesh; activated carbon should be washed repeatedly with distilled water to remove powdered carbon. The activated carbon particles above 100 mesh are too fine, and the ionic liquid loaded on the activated carbon will get wet soil-like solids, and it is impossible to obtain dry activated carbon-loaded particles; at the same time, the particle size of activated carbon is too small, which will increase the gas resistance, which is not conducive to adsorption. Therefore, the activated carbon between 40-100 mesh is selected for loading, and the effect is better.

(6) Immersion-Evaporation: Weigh 9-11g (preferably 10g) triethanolamine acetate ionic liquid, dissolve it in 29-31ml, preferably 30ml of ethanol, stir well and pour into accurately weighed activated carbon or silica gel Particles, stir evenly, and gradually increase the temperature, evaporate slowly, remove excess solvent, and stir continuously during the solvent evaporation process to ensure uniform loading.

(7) Drying: The prepared activated carbon/silica gel desulfurizer loaded with triethanolamine acetate ionic liquid was put into a vacuum oven at 50°C and dried to constant weight, and the obtained loaded ionic liquid was taken out.

(8) Storage: The storage conditions of the loaded ionic liquid are dry and sealed.

As a preference, the molar ratio of triethanolamine to acetic acid is (1.1-1.3): 1, preferably 1.2: 1; to ensure complete reaction of acetic acid, the triethanolamine acetate ionic liquid presents weak alkalinity (PH is about 9), which can Promote the adsorption of acid gas SO2 _; the molar ratio of triethanolamine to acetic acid is greater than 1.2, the alkalinity of the ionic liquid will increase, which will increase the corrosion of equipment.

As a preference, the power of the microwave reactor is set to 300W, the reaction temperature is 65°C, the flow rate can be controlled at 0.1L/min and the acetic acid in the adjustable dosing device can be dripped within 10min. into the three-necked flask;

As a preference, the loading ratio of triethanolamine acetate ionic liquid to activated carbon particles is between 0.5-1.5; if the ratio is greater than 1.5, the loaded activated carbon particles will appear muddy, which does not meet the adsorption requirements; when the ratio is less than 0.5, the ionic liquid content Small, the adsorption effect is not obvious.

As a preference, choose a porous carrier such as activated carbon or silica gel with a particle size between 40-100 mesh; wherein the activated carbon particles should be washed repeatedly with distilled water to remove powdered carbon, and placed in a drying oven at 110 ° C for drying;

As a preference, under the condition of 90°C, nitrogen gas is passed into the used desulfurizer, and the flow rate can be controlled at 500ml/min until the SO2 concentration reaches the discharge standard, thereby realizing regeneration _;

The above regeneration method is a mechanism experiment regeneration. In order to meet the large-scale application conditions of power plants and utilize the waste heat and tail gas of flue gas at the same time, the following system process is used for regeneration operation, and at the same time, the adsorbed SO ₂ is collected and processed. Recovery of waste heat after desulfurization to assist regeneration system, including:

(1) The flue gas first passes through the air preheater and heat exchanger to cool down to below 50°C, then enters the activated carbon desulfurizer loaded with triethanolamine acetate ionic liquid for adsorption, and the purified flue gas is then discharged from the reaction tower and enters the chimney discharge.

(2) After the desulfurizer in the reaction tower is saturated, desorption is carried out. The desorption gas is N ₂ , and the heat source of N ₂ is the compression and heat release of the compressor, so that the temperature of N ₂ reaches about 90-100°C and then enters the desorption tower for desorption. Desorption.

(3) After desorption, the generated desorbed mixed gas (N ₂ and SO ₂ ) first passes through the gas-solid separator to separate the desulfurizer particles mixed with it, and the desorbed mixed gas is sucked into the compressor by the booster fan , SO ₂ enters the gas storage tank or the acid system after being compressed by the compression device. The heat generated in the compression process is cooled by _N2 through the heat exchanger and then enters the desorption tower to form a cycle of the desorption system.

(4) When the desorption gas required by the desorption system is sufficient, the air directly enters the air preheater after exchanging heat with the flue gas through the heat exchanger; the heat exchange medium of _N2 in the heat exchanger is air, and after the air is heated It also enters the air preheater, which provides the hot air needed in the boiler. The whole system makes full use of the waste heat of the flue gas and the heat released by the compression of the compressor to realize the repeated utilization of the activated carbon-loaded ionic liquid desulfurizer and the resource utilization of SO ₂ .

Heat exchange pipes are arranged in the first heat exchanger and/or the second heat exchanger, and the heat exchange pipes are shown in Fig. 2-5. As shown in Figure 2, it includes a central tube 125, a left tube 123, a right tube 124 and a coil 12, the coil 12 is multiple, and each coil 12 includes a plurality of arc-shaped heat exchange tubes 15, correspondingly The ends of the adjacent heat exchange tubes 15 are communicated so that a plurality of heat exchange tubes 15 form a series structure, and the ends of the heat exchange tubes 15 form the free ends 13 and 14 of the heat exchange tubes; the coil 12 includes a left coil 121 and the right coil pipe 122, one side of the middle pipe 125 is connected to the inlet of the left coil pipe 121, the other side is connected to the inlet of the right coil pipe 122, the outlet of the left coil pipe 121 is connected to the left pipe 123, and the outlet of the right coil pipe 122 is connected to the right Ministry tube 122. The left coil outlet and the right coil outlet are arranged on one side of the middle tube; the left tube group and the right tube group are mirror-symmetrical along the plane where the axis center of the middle evaporation tube is located.

The air passes through the inlet of the middle tube 125 and enters the left and right coils. Under the impact of the fluid flow, the heat exchange tube bundle vibrates, which can reduce dust accumulation, and then the outermost heat exchange tube passes through the flow inside the heat exchange tube and finally passes through The outlet flow path of the innermost heat exchange tube is the outlet standpipe, and finally flows out through the outlet standpipe.

In the present invention, by improving the previous application, the coils are respectively arranged as two distributed on the left and right, and the outlet of the left coil and the outlet of the right coil are arranged on one side of the middle pipe, so that the coils distributed on the left and right sides can Vibration is carried out to expand the vibration area, the more uniform the vibration can be, the enhanced heat transfer and the reduced dust deposition effect.

Preferably, the shell of the heat exchanger has a circular section, and the opening formed between the ends of the free ends faces the center of the circular section of the heat exchanger. Makes heat exchange and vibration to the inside, enhancing heat transfer.

Preferably, the left coil is centered on the axis of the left tube, and the right coil is centered on the axis of the right tube. By setting the left and right coils as the center of the circle, the distribution of the coils can be better ensured, so that the vibration and heating are even.

The plurality of coiled tubes 12 on the same side are in a parallel structure and arranged along the height direction of the middle tube 125 .

Preferably, the left tube 123 and the right tube 124 are distributed mirror-symmetrically along the plane where the axis of the middle tube 125 is located.

The symmetrical structural distribution of the right pipe through the left and right coils can make the vibration more uniform and enhance the heat exchange and dust removal effects.

Preferably, the left coil tube 121 and the right coil tube 122 are arranged in a staggered arrangement in the height direction, as shown in Fig. 3-4. Through the staggered distribution, vibration heat exchange and dust removal can be performed at different heights, making the vibration more uniform and enhancing the effects of heat transfer and dust removal.

Preferably, the inlet direction of the middle pipe 125 is located at the lower end of the middle pipe 125 . By setting it at the lower end, the pulsed air flow flows from the lower end to the upper end, and fills up the coil in turn, which can ensure that the air flow fully fills the entire heat exchange tube and reduces heat exchange short circuit.

Preferably, as shown in FIGS. 2 and 3 , along the height direction of the middle pipe 125 , there are multiple coiled pipes 13 on the same side (left or right). Along the direction from the upper end to the lower end of the middle tube 125 , the tube diameters of the heat exchange tubes of the coil tubes on the same side are constantly increasing. Because it is found in experiments and practice that as the heat exchange continues, the lower the lower end, the easier it is for the heat exchange tubes to accumulate dust. Therefore, the distribution of the tube diameters passing through the lower end is larger, so that the distribution of the air flow at the lower end The higher the flow rate, the higher the frequency of vibration and the better the effect of dust removal, resulting in a significant increase in the overall heat transfer effect.

Preferably, along the direction from the upper end to the lower end of the middle tube 125 , the tube diameters of the heat exchange tubes of the coil tubes on the same side increase continuously. Because it is found in experiments and practice that with the continuous heat transfer, the speed of ash accumulation is not proportional to the distribution from top to bottom, but the increase of ash accumulation is also increasing. Therefore, the diameter of the pipe passing through the lower end The greater the range of change, the greater the increase in the flow rate of the air flow distributed at the lower end, the greater the increase in the vibration frequency, and the better the dust removal effect, resulting in a significant increase in the overall heat transfer effect.

Preferably, along the height direction of the middle tube 125, multiple coils are arranged on the same side, and along the direction from the upper end to the lower end of the middle tube 125, the distance between the coil heat exchange tubes on the same side becomes smaller. Because it is found in experiments and practice that as the heat exchange continues, the lower the end, the better the heat exchange effect. Therefore, the distribution of the pulsating tubes passing through the lower end is denser, so that the flow rate of the air flow distributed at the lower end is also more. , so that the greater the frequency of vibration, the better the heat transfer effect, resulting in a significant increase in the overall heat transfer effect.

Preferably, along the direction from the upper end to the lower end of the middle tube 125 , the spacing between the heat exchange tubes of the coil tubes is continuously reduced and the range is continuously increased. Because it is found in experiments and practice that as the heat transfer continues, from top to bottom, the speed of the heat transfer effect is not proportional to the distribution, but the range of the heat transfer effect is also increasing, so through this lower end The greater the variation of the distribution density, the greater the increase of the flow rate of the air flow distributed at the lower end, the greater the increase of the vibration frequency, and the better the heat exchange effect, resulting in a significant increase in the overall heat exchange effect.

Preferably, a plurality of heat exchange tubes are arranged in the heat exchanger/second heat exchanger. The system also includes a controller, the controller automatically detects the heat exchange heat of each heat exchange pipe, and then calculates the average heat exchange heat of the heat exchange pipe according to the weighted average, and automatically adjusts each heat exchange according to the average heat exchange. Swap the air flow of the fittings.

The heat exchange capacity of the heat exchange pipe fittings is obtained by calculating the fluid temperature and flow rate at the inlet and outlet.

By detecting and calculating the average heat transfer rate, it is possible to automatically detect the heat transfer condition of each heat exchange tube, and then determine whether the dust removal vibration and the strength of the dust removal vibration are required, so that each heat exchange tube can achieve heat storage The overall heat exchange in the tank is uniform.

Preferably, if the heat exchange value of a certain heat exchange pipe detected by the controller is lower than the average heat exchange by a certain value, for example, 10% lower than the average heat exchange, the controller controls to automatically increase the air flow of the heat exchange pipe. By increasing the air flow rate, on the one hand, it can increase the removal of dust accumulation and reduce the reduction of heat transfer efficiency caused by dust accumulation.

Preferably, if the heat exchange value of a certain heat exchange pipe detected by the controller is higher than the average heat exchange by a certain value, for example, 10% higher than the average heat exchange, the controller controls to automatically reduce the air flow of the heat exchange pipe. By reducing the air flow rate, the heat transfer can be reduced by reducing the vibration, so that the heat transfer can reach the average value. So that the overall heat transfer is uniform.

Preferably, the inlet pipeline of each heat exchange pipe is provided with a valve, and the flow rate of air entering each heat exchange pipe is controlled by the valve.

Although the present invention has been disclosed above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention should be based on the scope defined in the claims.

Claims (4)

1. An asymmetrically arranged heat exchanger, the heat exchanger includes a header, and the left and right coils are distributed on the left and right sides of the header, and it is characterized in that the left coil and the right coil Arranged at intervals, a right coil is arranged between two adjacent left coils, and a left coil is arranged between two adjacent right coils. 2. The heat exchanger according to claim 1, characterized in that it comprises a left pipe and a right pipe as headers of the left coil and the right coil. 3. A flue gas waste heat utilization system, comprising the heat exchanger according to any one of claims 1-2. 4. The system according to claim 3, characterized in that it comprises an air preheater, a first heat exchanger, a second heat exchanger, a first absorption/desorption tower, a second absorption/desorption tower, and a gas-solid separator , fan, gas storage and acid production device, compressor and chimney, the air preheater is connected to the heat exchanger, and the flue gas cooled by the air preheater enters the first heat exchanger and the air in the heat exchanger for two Secondary heat exchange, the heated air is sent back to the air preheater for secondary reheating; the first heat exchanger is also used as a heater for the desorption system to start the nitrogen, and the heated nitrogen passes through the pipeline and the absorption/desorption tower Connection; the flue gas side of the second heat exchanger is connected to the absorption/desorption tower, the upper part of the absorption/desorption tower is connected to the chimney through a pipeline, and the bottom of the absorption/desorption tower is connected to the gas-solid separator through a pipeline, and the gas-solid separator is followed by The fan is connected to the compressor, and the compressor is respectively connected to the gas storage and acid production device and the second heat exchanger through pipelines.