Double-circulation high-salinity wastewater purified flue gas reheating concentration system

Abstract

A double-circulation high-salinity wastewater purified flue gas reheating concentration system comprises an air preheater, a first-stage flue gas cooler, a second-stage flue gas cooler, an electrostatic dust collector, a flue gas induced draft fan, an output flue, a desulfurizing absorption tower, a chimney, a purified flue gas inlet flue, an inlet flue air door, a first-stage flue gas heater, a second-stage flue gas heater, a purified flue gas induced draft fan, a concentration tower, a wet flue gas outlet flue and an outlet flue air door. The system comprises first and second cold demineralized water pipelines, first and second demineralized water circulating pumps, first and second hot demineralized water pipelines, and first and second nitrogen pressure stabilizers. The internal pressure is stabilized, energy is saved, emission is reduced, energy consumption is reduced, operation is safe and reliable, low-temperature corrosion of the flue is avoided, a flue gas flow field in the concentration tower is guaranteed, corrosion and scaling are avoided, the service life is long, environment friendliness is achieved, system performance is improved, and operation cost is reduced. The method can be widely applied to the high-salinity wastewater treatment process, especially the boiler desulfurization wastewater treatment process.

Description

Technical Field

[0001] The invention relates to a double-circulation high-salt wastewater clean flue gas reheating concentration system, which can be widely used in high-salt wastewater treatment processes, in particular in boiler desulfurization wastewater treatment processes. Background Art

[0002] High-salinity wastewater is highly polluting and requires zero-discharge treatment. Generally, heat is used to evaporate water from high-salinity wastewater to achieve the purpose of concentrating and reducing the total amount of wastewater.

[0003] The flue gas in the tail flue of the boiler contains a lot of waste heat. The traditional technology is to directly use the induced draft fan to draw out the undesulfurized flue gas as a concentrated heat source. This type of technical system is simple, but there are many problems and shortcomings in its operation: (1) Corrosion hazards. This type of technology directly draws out flue gas from the flue in front of the desulfurization absorption tower. The flue gas contains a large amount of SO2, which will cause two types of unavoidable corrosion: First, low-temperature corrosion of flue gas. The flue gas temperature at the inlet of the desulfurization tower is relatively low, and then it is cooled by the flue, especially the influence of the ambient air introduced by the cooling fan and the sealing fan of the induced draft fan, which causes acid condensation in the flue gas, causing corrosion of the fan and flue, and the system cannot operate normally; second, the corroded flue, fan and damper will cause damage to related components, resulting in flue gas leakage and environmental pollution.

[0004] (2) Acid corrosion in the concentration tower. After SO2 enters the concentration tower, it will dissolve in the high-salt wastewater, causing the pH value of the wastewater to reach 0.5-1.0; the acidic environment causes serious corrosion to the entire system equipment, equipment damage, and a short service life of the equipment.

[0005] (3) Scaling effect. Traditional technology directly draws flue gas from the flue in front of the desulfurization absorption tower without being washed by the desulfurization absorption tower. The flue gas contains not only a large amount of SO2, but also a large amount of PM2.5 fine particles. These fine particles are high-quality materials for making cement. They are hydraulic materials. Not only do they have a large specific surface energy, but they will also wrap the suspended crystal seeds in the wastewater when they encounter wastewater, exacerbating the scaling tendency of the wastewater itself. At the same time, the fine particles will harden when they encounter water, eventually leading to serious scaling of the system and frequent maintenance.

[0006] (4) It is neither energy-saving nor environmentally friendly. Because the pH value of the concentrated solution can reach 0.5-1.0, the high-salt wastewater contains a large amount of chloride ions, which can produce volatile hydrogen chloride gas. These volatile hydrogen chloride gases not only cause flue corrosion, but also cause pollutant circulation in the desulfurization absorption tower. Because of the strong acidic pH value, in order to ensure the stability of the subsequent drying zero-emission system, it is necessary to add drugs for neutralization and conditioning; the added drug solution contains a large amount of water, which increases the output of the drying system and also increases energy consumption. Summary of the invention

[0007] The purpose of the present invention is to provide a double-circulation high-salt wastewater clean flue gas reheat concentration system with internal voltage stabilization, energy saving and emission reduction, reduced energy consumption, safe and reliable operation, avoidance of low-temperature corrosion of the flue, ensuring the flue gas flow field in the concentration tower, no corrosion, no scaling, long service life, environmental protection, improved system performance, and reduced operating costs.

[0008] In order to achieve the above-mentioned purpose, the double-circulation high-salt wastewater clean flue gas reheating and concentrating system of the present invention comprises an air preheater connected to the boiler through the boiler flue, a primary flue gas cooler connected to the air preheater through the flue, an electrostatic precipitator connected to the primary flue gas cooler through the flue, a secondary flue gas cooler connected to the electrostatic precipitator through the flue, a flue gas induced draft fan connected to the secondary flue gas cooler through the flue, an output flue connected to the output end of the flue gas induced draft fan, a desulfurization absorption tower connected to the end of the output flue, a chimney connected to the top outlet of the desulfurization absorption tower through a clean flue gas pipeline, a clean flue gas inlet flue connected to the clean flue gas pipeline, an inlet flue damper, a primary flue gas heater, a clean flue gas induced draft fan, a secondary flue gas heater installed in sequence on the clean flue gas inlet flue from top to bottom, a concentrating tower connected to the end of the clean flue gas inlet flue, one end of which is connected to the top outlet of the concentrating tower and the other end is located at the flue A wet flue gas outlet duct between the induced draft fan and the desulfurization absorption tower and connected to the output flue, an outlet flue damper installed on the wet flue gas outlet duct, a first cold desalted water pipe connected to the input end of the first-level flue gas cooler at one end and to the output end of the second-level flue gas heater at the other end, a first desalted water circulating water pump installed on the first cold desalted water pipe, a first hot desalted water pipe connected to the output end of the first-level flue gas cooler at one end and to the input end of the second-level flue gas heater at the other end, a first nitrogen pressurizer installed on the first hot desalted water pipe, a second cold desalted water pipe connected to the input end of the second-level flue gas cooler at one end and to the output end of the first-level flue gas heater at the other end, a second hot desalted water pipe connected to the output end of the second-level flue gas heater at one end and to the input end of the first-level flue gas heater at the other end, a second nitrogen pressurizer installed on the second hot desalted water pipe, and a second desalted water circulating water pump.

[0009] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the concentration tower is a cylindrical tower or a rectangular tower.

[0010] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention further includes a demister disposed on the upper part of the concentration tower.

[0011] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention has a clean flue gas inlet flue that, in order to ensure the flue gas flow field in the concentration tower, has a clean flue gas inlet flue that penetrates into the tower at the air inlet of the concentration tower to a depth of 1 / 3 to 1 / 2 of the tower body diameter or width.

[0012] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention has a clean flue gas inlet flue, in order to ensure that the sprayed wastewater does not accumulate on the top wall of the air inlet and eliminate corrosion and scaling, the clean flue gas inlet flue at the air inlet of the concentration tower has an angle of 3° to 15° with the horizontal plane.

[0013] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the desulfurization absorption tower is also provided with a desulfurization tower spray device on its upper part, a desulfurization tower wastewater circulation pipeline with one end installed at the bottom of the desulfurization absorption tower and connected with the bottom desulfurization wastewater and the other end connected to the desulfurization tower spray device, and a desulfurization tower wastewater circulation water pump installed on the desulfurization tower wastewater circulation pipeline.

[0014] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the concentration tower is also provided with a wastewater circulation system, the wastewater circulation system includes a wastewater circulation pipeline connected to the side of the wastewater at the bottom of the concentration tower, a wastewater circulation water pump installed on the wastewater circulation pipeline, and a spray device connected to the end of the wastewater circulation pipeline and installed on the cylinder of the concentration tower.

[0015] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention has 2 to 5 spray devices.

[0016] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the concentration tower is also provided with a wastewater discharge system, the wastewater discharge system includes a wastewater discharge pipe arranged on the ground side of the concentration tower, a wastewater discharge device connected to the end of the wastewater discharge pipe, and a drainage pump located between the concentration tower and the wastewater discharge device and installed on the wastewater discharge pipe.

[0017] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the wastewater discharge device is also provided with a wastewater discharge stirring device.

[0018] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the concentration tower is also provided with an overflow water system, the overflow water system includes an overflow water pipe arranged at the water level height limit at the bottom of the concentration tower, and an overflow water device connected to the end of the overflow water pipe.

[0019] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the overflow water device is also provided with an overflow water stirring device.

[0020] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the concentration tower is also provided with a wastewater inlet pipe, a wastewater supply device connected to the end of the wastewater inlet pipe, a water supply pump located between the concentration tower and the wastewater supply device and installed on the wastewater inlet pipe, and a wastewater supply pipe installed on the wastewater supply device.

[0021] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the wastewater supply device is also provided with a wastewater supply stirring device.

[0022] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention has the following working principles: (1) The boiler flue gas passes through the boiler flue, air preheater, primary flue gas cooler, electrostatic precipitator, flue gas induced draft fan, and secondary flue gas cooler in sequence. The flue gas induced draft fan introduces the cooled and dust-removed output flue gas into the desulfurization absorption tower. After the flue gas is washed in the desulfurization absorption tower, the last part of the clean flue gas is discharged from the chimney.

[0023] (2) The present invention extracts clean flue gas through a clean flue gas induced draft fan, and the clean flue gas is heated by a two-stage flue gas heater to form hot clean flue gas, so that the hot clean flue gas has enough heat to evaporate high-salt wastewater. The hot clean flue gas enters the concentration tower through the clean flue gas inlet flue, and this part of the hot clean flue gas is used to evaporate the wastewater sprayed from top to bottom by the spray device. The hot clean flue gas and the cold wastewater transfer heat and mass in countercurrent, the hot clean flue gas rises and decreases in temperature to absorb moisture, and the cold wastewater descends and increases in temperature to evaporate. The wastewater is evaporated by continuous spraying cycles, and is discharged from the wastewater discharge device after reaching the set concentration ratio.

[0024] (3) The present invention adopts the form of dual flue gas coolers, dual flue gas heaters and dual nitrogen regulators. The circulation system composed of the two-stage flue gas cooler and the two-stage flue gas heater relies on the internal dual nitrogen regulator for voltage stabilization. The flow path of the desalted water is as follows: the first water circulation system: part of the hot water is drawn out from the outlet of the first flue gas cooler, through the first hot desalted water pipeline, through the first nitrogen regulator, and into the second flue gas heater; then through the output end of the second flue gas heater, through the first cold desalted water pipeline, through the first desalted water circulation water pump to provide power, and then into the first flue gas cooler. The second water circulation system: part of the hot water is drawn out from the outlet of the second flue gas cooler, through the second hot desalted water pipeline, through the second nitrogen regulator, the second desalted water circulation water pump, and into the first flue gas heater; then through the output end of the first flue gas heater, through the second cold desalted water pipeline, and into the second flue gas cooler. In this way, the two water circulation systems operate independently without interfering with each other, and each water circulation system is provided with a nitrogen regulator for voltage stabilization.

[0025] (4) In the concentration tower, the concentration tower is provided with multiple interfaces, and the height of each interface is, from low to high, the drain outlet, the water inlet, the circulating water outlet, the overflow outlet, the air inlet, the circulating water inlet and the exhaust outlet. The drain outlet of the wastewater discharge pipe is set at the lowest position of the concentration tower, which is beneficial to discharge the concentrated liquid; the water inlet of the wastewater inlet pipe is set at the low position of the concentration tower, which is beneficial to impact the concentrated liquid and produce a stirring effect; the circulating water outlet of the wastewater circulation pipe is set at a lower position to ensure the concentration ratio; the overflow outlet of the overflow water pipe is set below the air inlet of the clean flue gas inlet flue of the concentration tower, which is beneficial to protect the air inlet from the influence of wastewater; the air inlet of the clean flue gas inlet flue of the concentration tower is set below the circulating water inlet of the wastewater circulation pipe of the concentration tower, that is, below the spray layer, to ensure the heat and mass transfer performance between the flue gas and the wastewater; the exhaust outlet of the wet flue gas outlet flue is set at the top of the concentration tower, which is beneficial to the flue gas to be discharged to the higher main flue after demisting.

[0026] In the double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the clean flue gas induced draft fan provides power for extracting the clean flue gas.

[0027] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the inlet flue duct damper and the outlet flue duct damper are used to adjust and close the flue gas flow.

[0028] In the double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the electrostatic precipitator separates and filters the dust, smoke and particulate matter generated during the working process by physical methods to reduce their harm to the environment and human body. The temperature of the flue gas is very high, which makes the flue gas in the pipeline pass through the dust collector in a short time, and the humidity generated by the wall of the dust collector is relatively large, which leads to the dust collector being prone to scaling, clogging and other problems. At the same time, under high temperature conditions, the temperature of the dust collector filter bag will also increase, causing the filter bag to deform and rupture, and the filtration efficiency of the dust collector to decrease. Based on this, the present invention installs a primary and secondary flue gas cooler before and after the electrostatic precipitator. First, the temperature of the flue gas can be greatly reduced, which can reduce the risk of wear and clogging of the electrostatic precipitator equipment, and improve the dust removal efficiency and ensure the stable operation of the dust collector; secondly, after reducing the temperature of the flue gas, the content of pollutants will also become smaller, reducing the cleaning frequency of the dust collector and improving production efficiency; thirdly, the exhaust gas emission temperature is reduced to reduce the impact on the environment; finally, a suitable flue gas desulfurization temperature is provided to the subsequent desulfurization absorption tower to achieve the purpose of energy saving and emission reduction.

[0029] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention adopts a countercurrent heat exchange method between flue gas and heat medium water. The countercurrent heat exchange can make full use of the waste heat of high-temperature flue gas, improve the logarithmic mean temperature difference, have a good heat exchange effect, reduce the heat exchange area, and save energy. In addition, the clean flue gas inlet flue of the present invention is arranged in the clean flue gas pipeline between the outlet of the desulfurization absorption tower and the chimney. This part of the clean flue gas is cooled, dust-removed, concentrated and washed in the front, so SO2 and fine particulate matter are removed, and emissions are reduced. Therefore, the present invention saves energy and reduces emissions.

[0030] The externally stabilized single cooling type high-salt wastewater clean flue gas reheating concentration system of the present invention has the advantages of firstly, that it adopts a two-stage flue gas heater structure, and the induced draft fan is selected with small specifications, which saves energy and reduces consumption. Because the heat of the clean flue gas introduced by the concentration tower should not be less than the heat required for evaporating the wastewater, and the heat of the clean flue gas = flue gas temperature difference × net flue gas volume, the present invention sets a two-stage flue gas heater, firstly heats the clean flue gas through the first-stage flue gas heater, and then introduces the clean flue gas into the second-stage flue gas heater through the clean flue gas induced draft fan, and heats the clean flue gas again in the second-stage flue gas heater. The two clean flue gas heatings can reduce the required amount of clean flue gas, and also reduce the amount of air introduced by the induced draft fan. Therefore, the clean flue gas induced draft fan is selected with small specifications. Secondly, similarly, a two-stage flue gas cooler structure is adopted, and the flue gas induced draft fan is selected with small specifications, which saves energy and reduces consumption. Because the flue gas heat introduced by the desulfurization absorption tower should not be less than the heat required by the desulfurization absorption tower, and the flue gas heat = flue gas temperature difference × flue gas volume, the present invention sets a two-stage flue gas cooler, first cools the flue gas through the first-stage flue gas cooler, and then introduces the flue gas into the second-stage flue gas cooler through the flue gas induced draft fan, and the flue gas is cooled again in the second-stage flue gas cooler. The two flue gas cooling can reduce the required flue gas volume, which also reduces the air volume introduced by the flue gas induced draft fan. Therefore, the flue gas induced draft fan has a small selection specification and provides a suitable flue gas desulfurization temperature. Compared with the traditional technology, although the power consumption of the desalted water circulating water pump is increased, the wind temperature of the induced draft fan is reduced from the traditional 95℃~120℃ to 55℃~60℃, the flue gas flow rate is reduced to 85%~89%, and the power consumption of the induced draft fan is reduced more, thus saving energy and reducing consumption.

[0031] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention supplies the high-salt wastewater to be treated into the concentration tower from the wastewater supply device during operation, and the overflow water device is a safety protection device for limiting the height of the wastewater liquid level, so the operation is safe and reliable.

[0032] The double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention heats the clean flue gas through a two-stage flue gas heater, thereby avoiding low-temperature corrosion of the flue caused by a low-temperature environment, that is, avoiding low-temperature corrosion of the flue, which is beneficial to reducing energy consumption.

[0033] In the double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the clean flue gas inlet flue at the air inlet of the concentration tower penetrates into the tower to a depth of 1 / 3 to 1 / 2 of the tower body diameter or width, thereby ensuring the flue gas flow field in the concentration tower.

[0034] In the double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the angle between the clean flue gas inlet flue at the air inlet of the concentration tower and the horizontal plane is 3° to 15°, ensuring that the sprayed wastewater does not accumulate on the top wall of the air inlet, eliminating corrosion and scaling.

[0035] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention uses clean flue gas as a water carrier. First, the flue gas cooler indirectly utilizes the flue gas waste heat, and there is no corrosion problem, so there is no corrosion; second, using clean flue gas as a water carrier, there is no scaling problem caused by fine particles, so there is no scaling; third, using clean flue gas as a water carrier, the pH value of the concentrated liquid remains basically unchanged, there is no hydrogen chloride gas volatilization problem, and no need for adding medicine to quench and temper, so it is environmentally friendly. It is precisely because of the avoidance of corrosion and scaling that the equipment has a long service life, the system performance is improved, and the operating cost is reduced.

[0036] In summary, the double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention has internal voltage stabilization, energy saving and emission reduction, reduced energy consumption, safe and reliable operation, avoids low-temperature corrosion of the flue, ensures the flue gas flow field in the concentration tower, is corrosion-free, scale-free, has a long service life, is environmentally friendly, improves system performance, and reduces operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments thereof.

[0038] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0039] exist Figure 1In the present invention, the double-circulation high-salt wastewater clean flue gas reheating and concentrating system comprises an air preheater 3 connected to a boiler 1 through a boiler flue 2, a primary flue gas cooler 4 connected to the air preheater through the flue, an electrostatic precipitator 5 connected to the primary flue gas cooler through the flue, a secondary flue gas cooler 6 connected to the electrostatic precipitator through the flue, a flue gas induced draft fan 7 connected to the secondary flue gas cooler through the flue, an output flue 8 connected to the output end of the flue gas induced draft fan, a desulfurization absorption tower 9 connected to the end of the output flue, a chimney 11 connected to the top outlet of the desulfurization absorption tower through a clean flue gas pipeline 10, a clean flue gas inlet flue 12 connected to the clean flue gas pipeline, an inlet flue damper 13, a primary flue gas heater 14, a clean flue gas induced draft fan 15, a secondary flue gas heater 16, a concentrating tower 17 connected to the end of the clean flue gas inlet flue, one end of which is connected to the top outlet of the concentrating tower and the other end is located at the flue gas inlet. A wet flue gas outlet flue 18 between the induced draft fan and the desulfurization absorption tower and connected to the output flue, an outlet flue damper 19 installed on the wet flue gas outlet flue, a first cold desalted water pipe 20 connected to the input end of the first-level flue gas cooler at one end and connected to the output end of the second-level flue gas heater at the other end, a first desalted water circulating water pump 21 installed on the first cold desalted water pipe, a first hot desalted water pipe 22 connected to the output end of the first-level flue gas cooler at one end and connected to the input end of the second-level flue gas heater at the other end, a first nitrogen pressurizer 23 installed on the first hot desalted water pipe, a second cold desalted water pipe 24 connected to the input end of the second-level flue gas cooler at one end and connected to the output end of the first-level flue gas heater at the other end, a second hot desalted water pipe 25 connected to the output end of the second-level flue gas heater at one end and connected to the input end of the first-level flue gas heater at the other end, a second nitrogen pressurizer 26 installed on the second hot desalted water pipe, and a second desalted water circulating water pump 27.

[0040] In the double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the concentration tower 17 is a cylindrical tower or a rectangular tower.

[0041] In the double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the concentration tower 17 is further provided with a demister 17-1 at its upper portion.

[0042] In the double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the clean flue gas inlet flue 12 is inserted into the tower to a depth L of 1 / 3 to 1 / 2 of the tower body diameter or width D at the air inlet of the concentrating tower to ensure the flue gas flow field in the concentrating tower.

[0043] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention has a clean flue gas inlet flue 12, which has an angle α of 3° to 15° with the horizontal plane at the air inlet of the concentration tower to ensure that the sprayed wastewater does not accumulate on the top wall of the air inlet and eliminate corrosion and scaling.

[0044] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the desulfurization absorption tower 9 is also provided with a desulfurization tower spray device 9-1 on its upper part, a desulfurization tower wastewater circulation pipeline 9-2 which is installed at one end at the bottom of the desulfurization absorption tower and connected with the desulfurization wastewater at the bottom and connected to the desulfurization tower spray device at the other end, and a desulfurization tower wastewater circulation water pump 9-3 installed on the desulfurization tower wastewater circulation pipeline.

[0045] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the concentration tower 17, is also provided with a wastewater circulation system, the wastewater circulation system includes a wastewater circulation pipe 17-2 connected to the side of the wastewater at the bottom of the concentration tower, a wastewater circulation water pump 17-3 installed on the wastewater circulation pipe, and a spray device 17-4 connected to the end of the wastewater circulation pipe and installed on the cylinder of the concentration tower.

[0046] In the double-circulation high-salt wastewater clean flue gas reheating concentration system of the present invention, the number of the spray devices 17-4 is 2 to 5.

[0047] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the concentration tower 17, is also provided with a wastewater discharge system, the wastewater discharge system includes a wastewater discharge pipe 17-5 arranged on the ground side of the concentration tower, a wastewater discharge device 17-6 connected to the end of the wastewater discharge pipe, and a drainage pump 17-7 located between the concentration tower and the wastewater discharge device and installed on the wastewater discharge pipe.

[0048] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the wastewater discharge device 17-6 is also provided with a wastewater discharge stirring device 17-6-1.

[0049] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the concentration tower 17, is also provided with an overflow water system, the overflow water system includes an overflow water pipe 17-8 arranged at the water level height limit at the bottom of the concentration tower, and an overflow water device 17-9 connected to the end of the overflow water pipe.

[0050] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the overflow water device 17-9 is also provided with an overflow water stirring device 17-9-1.

[0051] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the concentration tower 17 is also provided with a wastewater inlet pipe 17-10, a wastewater supply device 17-11 connected to the end of the wastewater inlet pipe, a water pump 17-12 located between the concentration tower and the wastewater supply device and installed on the wastewater inlet pipe, and a wastewater inlet pipe 17-13 installed on the wastewater supply device.

[0052] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention, the wastewater supply device 17-11 is also provided with a wastewater supply stirring device 17-11-1.

[0053] The double-circulation high-salt wastewater clean flue gas reheat concentration system of the present invention is only described above as a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A double-circulation high-salt wastewater clean flue gas reheating concentration system, characterized in that: The invention comprises an air preheater connected to the boiler through the boiler flue, a primary flue gas cooler connected to the air preheater through the flue, an electrostatic precipitator connected to the primary flue gas cooler through the flue, a secondary flue gas cooler connected to the electrostatic precipitator through the flue, a flue gas induced draft fan connected to the secondary flue gas cooler through the flue, an output flue connected to the output end of the flue gas induced draft fan, a desulfurization absorption tower connected to the end of the output flue, a chimney connected to the top outlet of the desulfurization absorption tower through a clean flue gas pipeline, a clean flue gas inlet flue connected to the clean flue gas pipeline, an inlet flue damper, a primary flue gas heater, a clean flue gas induced draft fan, a secondary flue gas heater, a concentrating tower connected to the end of the clean flue gas inlet flue, one end of which is connected to the top outlet of the concentrating tower, and the other end is located between the flue gas induced draft fan and the desulfurization absorption tower and connected to the exhaust port of the clean flue gas inlet. A wet flue gas outlet flue connected to the output flue, an outlet flue damper installed on the wet flue gas outlet flue, a first cold desalted water pipe connected to the input end of the first-level flue gas cooler at one end and to the output end of the second-level flue gas heater at the other end, a first desalted water circulating water pump installed on the first cold desalted water pipe, a first hot desalted water pipe connected to the output end of the first-level flue gas cooler at one end and to the input end of the second-level flue gas heater at the other end, a first nitrogen pressurizer installed on the first hot desalted water pipe, a second cold desalted water pipe connected to the input end of the second-level flue gas cooler at one end and to the output end of the first-level flue gas heater at the other end, a second hot desalted water pipe connected to the second hot desalted water pipe at one end and to the second desalted water circulating water pump.

2. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 1 is characterized in that: The concentration tower is a cylindrical tower or a rectangular tower.

3. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 1 is characterized in that: The concentration tower is also provided with a demister at its upper part.

4. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 1 is characterized in that: To ensure the flue gas flow field in the concentration tower, the clean flue gas inlet flue is inserted into the tower at the air inlet of the concentration tower to a depth of 1 / 3 to 1 / 2 of the tower body diameter or width.

5. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 1 is characterized in that: The clean flue gas inlet flue is designed to ensure that the sprayed wastewater does not accumulate on the top wall of the air inlet and eliminate corrosion and scaling. The angle between the clean flue gas inlet flue and the horizontal plane at the air inlet of the concentration tower is 3° to 15°.

6. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 1 is characterized in that: The desulfurization absorption tower is also provided with a desulfurization tower spray device on its upper part, a desulfurization tower wastewater circulation pipe with one end installed at the bottom of the desulfurization absorption tower and connected to the bottom desulfurization wastewater and the other end connected to the desulfurization tower spray device, and a desulfurization tower wastewater circulation water pump installed on the desulfurization tower wastewater circulation pipe.

7. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 1 is characterized in that: The concentrating tower is also provided with a wastewater circulation system, which includes a wastewater circulation pipe connected to the side of the wastewater at the bottom of the concentrating tower, a wastewater circulation water pump installed on the wastewater circulation pipe, and a spray device connected to the end of the wastewater circulation pipe and installed on the cylinder of the concentrating tower.

8. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 7 is characterized in that: The number of the spraying devices is 2 to 5.

9. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 1 is characterized in that: The concentrating tower is also provided with a wastewater discharge system, which includes a wastewater discharge pipe arranged on the ground side of the concentrating tower, a wastewater discharge device connected to the end of the wastewater discharge pipe, and a drainage pump located between the concentrating tower and the wastewater discharge device and installed on the wastewater discharge pipe.

10. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 9 is characterized in that: The wastewater discharge device is also provided with a wastewater discharge stirring device.

11. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 1 is characterized in that: The concentration tower is also provided with an overflow water system, which includes an overflow water pipe arranged at the water level limit position at the bottom of the concentration tower and an overflow water device connected to the end of the overflow water pipe.

12. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 11 is characterized in that: The overflow water device is also provided with an overflow water stirring device.

13. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 1 is characterized in that: The concentration tower is also provided with a wastewater inlet pipe, a wastewater supply device connected to the end of the wastewater inlet pipe, a water supply pump located between the concentration tower and the wastewater supply device and installed on the wastewater inlet pipe, and a wastewater supply pipe installed on the wastewater supply device.

14. The double-circulation high-salt wastewater clean flue gas reheating concentration system according to claim 13 is characterized in that: The wastewater supply device is also provided with a wastewater stirring device.

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