阅读说明：本技术 一种旁路烟气干燥废水的干燥系统及控制方法 (Drying system for drying wastewater by using bypass flue gas and control method ) 是由 殷波 于飞 聂华 周琴涛 于 2019-12-18 设计创作，主要内容包括：本发明提供一种旁路烟气干燥废水的干燥系统,其可以实现对系统参数的自动控制,不易出错,且可以不间断运行。其包括：干燥塔,干燥塔烟气出口接入除尘器；控制器和通过控制器电控连接的电控装置,电控装置包括：设置于干燥塔烟气进口的进口烟气控制阀、进口烟气温度测量仪,设置于干燥塔烟气出口的出口烟气控制阀、出口烟气温度测量仪、出口烟气含水率测定仪,设置于干燥塔雾化废水进口的废水进口控制阀,设置于干燥塔雾化废水进口和废水进口控制阀之间的进雾化器废水流量测量仪,在工艺水的水路上设置工艺水进口控制阀。同时本发明还提供了一种旁路烟气干燥废水的干燥系统的控制方法。(The invention provides a drying system for drying waste water by bypass flue gas, which can realize automatic control of system parameters, is not easy to make mistakes and can run uninterruptedly. It includes: a flue gas outlet of the drying tower is connected with a dust remover; controller and the electrically controlled device who connects through the controller is automatically controlled, and electrically controlled device includes: the system comprises an inlet flue gas control valve and an inlet flue gas temperature measuring instrument which are arranged at a flue gas inlet of a drying tower, an outlet flue gas control valve, an outlet flue gas temperature measuring instrument and an outlet flue gas water content measuring instrument which are arranged at a flue gas outlet of the drying tower, a waste water inlet control valve which is arranged at an atomized waste water inlet of the drying tower, an atomizer waste water flow measuring instrument which is arranged between the atomized waste water inlet of the drying tower and the waste water inlet control valve, and a process water inlet control valve which is arranged on a water path of process water. Meanwhile, the invention also provides a control method of the drying system for drying the waste water by using the bypass flue gas.)

1. A drying system for drying wastewater with bypass flue gas, comprising: the main flue gas inlet of the drying tower is connected with a flue of a flue gas system, and the flue gas distributor is arranged at the flue gas inlet of the drying tower; the method is characterized in that:

the drying tower uses a rotary atomizer to atomize the wastewater; it still includes: the controller with through the automatically controlled electrically controlled device who connects of controller, electrically controlled device includes: set up in the import flue gas control valve of drying tower flue gas import, import flue gas temperature measuring apparatu, set up in export flue gas control valve, export flue gas temperature measuring apparatu, the moisture content of export flue gas apparatus of drying tower exhanst gas outlet, set up in the waste water import control valve of drying tower atomizing waste water import, set up in drying tower atomizing waste water import with go into atomizer waste water flow measuring instrument between the waste water import control valve, the water route entry of technology water set up in waste water import control valve with go into between the atomizer waste water flow measuring apparatu, set up technology water import control valve on the water route of technology water.

2. The drying system for drying wastewater by using bypass flue gas as claimed in claim 1, wherein: and the interface of the flue gas outlet access flue of the drying tower is connected with the inlet front main flue tee of the dust remover.

3. The drying system for drying wastewater by using bypass flue gas as claimed in claim 1, wherein: it also includes baffle doors positioned at all flue inlets and outlets of the drying tower.

4. The drying system for drying wastewater by using bypass flue gas as claimed in claim 1, wherein: the baffle door arranged at the smoke inlet of the drying tower is an adjustable baffle door, and the baffle doors on other smoke paths are opening-closing type baffle doors.

5. The drying system for drying wastewater by using bypass flue gas as claimed in claim 4, wherein: the flapper doors all adopt double-layer sealing shutter flapper doors, and the inlet of the heating sealing gas for sealing the flapper doors is controlled by an independently arranged sealing air pipeline subsystem.

6. The drying system for drying wastewater by using bypass flue gas as claimed in claim 5, wherein: the sealed air pipeline subsystem comprises a sealed fan and a sealed air pipeline system connected with each baffle door; the sealing fan is connected with the sealing wind power heater through an air pipeline, and sealing gas is heated to be higher than 100 ℃ through the sealing wind power heater and then is input into the sealing layer of the baffle door; the seal air pressure in the flapper door is at least 0.5Kpa higher than the flue gas pressure in the drying tower; the wind power generation device is characterized in that a sealing wind pressure tester is arranged between the sealing fan and the sealing wind power heater, and a sealing wind temperature tester is arranged at an outlet of the sealing wind power heater.

7. The drying system for drying wastewater by using bypass flue gas as claimed in claim 1, wherein: the bottom of the drying tower is provided with a crusher and a rapping device.

8. The drying system for drying wastewater by using bypass flue gas as claimed in claim 1, wherein: the body of the drying tower and the flue gas distributor adopt high-temperature-resistant boiler steel and a corrosion-resistant coating.

9. The method for controlling the implementation of a drying system for drying waste water by-pass flue gas according to claim 1, characterized in that it comprises:

controlling the inlet amount of wastewater and the inlet amount of flue gas for drying in an interlocking manner: after a wastewater inlet control valve arranged at an atomized wastewater inlet of the rotary atomizer is started, when an inlet atomizer wastewater flow measuring instrument detects that the flow of wastewater entering the rotary atomizer is increased, a controller starts an inlet flue gas control valve and an inlet flue gas temperature measuring instrument which are arranged at a flue gas inlet of a drying tower, and automatically adjusts drying flue gas entering the drying tower according to the increased flow of the wastewater, so that the heat of the drying flue gas is matched with the amount of the wastewater entering the rotary atomizer;

adjusting the water inflow of wastewater and the flue gas inflow through the water content of the outlet flue gas: arranging an outlet flue gas water content tester at a flue gas outlet of the drying tower, and monitoring the outlet flue gas water content in real time; when the water content of the outlet flue gas is higher than a preset outlet flue gas water content threshold value, the controller controls the opening degrees of the wastewater inlet control valve and the inlet flue gas control valve in an interlocking manner, and the water content of the outlet flue gas is controlled by adjusting the water inflow and the flue gas inflow;

adjusting the water inflow of the process water, the wastewater inlet amount for drying and the flue gas inlet amount through the outlet flue gas temperature: an outlet flue gas control valve and an outlet flue gas temperature measuring instrument are arranged at a flue gas outlet of the drying tower, and when the outlet flue gas temperature measuring instrument monitors that the outlet flue gas temperature is lower than a preset flue gas temperature dew point threshold value, the controller controls the opening of the inlet flue gas control valve in an interlocking mode, so that the flue gas quantity is increased, and the outlet flue gas temperature is further increased; when the outlet flue gas temperature measuring instrument monitors that the outlet flue gas temperature is higher than a preset tolerant temperature threshold value of the dust remover, the controller interlockingly increases the opening degrees of a process water inlet control valve and a waste water inlet control valve, so that the amount of water entering the drying tower through the rotary atomizer is increased, and the outlet flue gas temperature is reduced;

controlling corrosion prevention of the drying tower: when the drying tower is started, the controller starts the inlet flue gas temperature measuring instrument to measure the inlet flue gas temperature, and when the inlet flue gas temperature is lower than the flue gas temperature dew point threshold, the controller locks the process water inlet control valve and the wastewater inlet control valve to control the process water inlet control valve and the wastewater inlet control valve to stop starting until the inlet flue gas temperature is higher than the flue gas temperature dew point threshold.

10. The drying method of the bypass flue gas drying wastewater as claimed in claim 9, wherein: it still includes: when the drying tower is separated from the main system and stops running, the controller closes a flue damper door at the inlet and the outlet of the system, and simultaneously blows sealing air into the damper door through the sealing air pipeline subsystem; then the controller monitors the temperature of the sealing wind in real time through a sealing wind temperature tester arranged at an outlet of the sealing wind power heater, and once the temperature of the sealing wind is lower than 100 ℃, the sealing wind power heater is started to heat until the temperature is higher than 100 ℃; the controller is through installing on sealed wind pipeline sealed wind pressure tester real-time supervision seals the pressure value of wind, through setting up the inside flue gas pressure value of dry tower is monitored to the flue gas pressure tester in the drying tower, sealed air pressure must keep being higher than flue gas pressure value, when the difference of the two is less than 0.5Kpa, starts sealed fan and increases sealed air pressure is greater than 0.5Kpa until the difference of the two.

Technical Field

The invention relates to the technical field of wastewater purification and drying devices, in particular to a drying system for drying wastewater by using bypass flue gas and a control method.

Background

The bypass flue evaporation technology is a simple and effective wastewater zero-discharge treatment technology for directly evaporating and drying wastewater to be desulfurized or desalted by using the heat of boiler flue gas. The principle of the method is as shown in fig. 1, a high-temperature flue gas is led out from a flue between a Selective Catalytic Reduction (SCR) and a dust remover 3 in a flue gas system of a boiler 1, the flue gas is led into a drying tower 4, the flue gas enters the drying tower 4 in a spiral shape through a flow guide grid at the top of the drying tower, fully contacts with atomized wastewater, water is evaporated by utilizing the heat of the flue gas, tail gas discharged by the drying tower and gas discharged by an air preheater 5 (marked as an air preheater in the figure) in the flue gas system of the boiler are led into the dust remover 3 together, and the tail gas is treated by the dust remover 3 and then enters a subsequent purification process. Part of solid matters such as salt, suspended matters and the like contained in the wastewater are discharged into a dust remover along with the flue gas, and the other part of the solid matters are settled to the bottom of the drying tower 4 and discharged by a deslagging system.

However, most of the existing drying systems using the bypass flue evaporation technology manually control system parameters such as the wastewater inlet and outlet amount, the drying flue gas inlet and outlet amount and the like, and the existing drying systems depend on the experience and the capability of technicians, are labor-consuming and are very easy to make mistakes.

Disclosure of Invention

In order to solve the problems that an existing bypass flue gas drying system is high in labor cost and prone to error based on manual control, the invention provides a drying system for bypass flue gas drying wastewater, which can achieve automatic control over system parameters, is not prone to error and can run uninterruptedly. Meanwhile, the invention also provides a control method of the drying system for drying the waste water by using the bypass flue gas.

The technical scheme of the invention is as follows: a drying system for drying wastewater with bypass flue gas, comprising: the main flue gas inlet of the drying tower is connected with a flue of a flue gas system, and the flue gas distributor is arranged at the flue gas inlet of the drying tower; the method is characterized in that:

the drying tower uses a rotary atomizer to atomize the wastewater; it still includes: the controller with through the automatically controlled electrically controlled device who connects of controller, electrically controlled device includes: set up in the import flue gas control valve of drying tower flue gas import, import flue gas temperature measuring apparatu, set up in export flue gas control valve, export flue gas temperature measuring apparatu, the moisture content of export flue gas apparatus of drying tower exhanst gas outlet, set up in the waste water import control valve of drying tower atomizing waste water import, set up in drying tower atomizing waste water import with go into atomizer waste water flow measuring instrument between the waste water import control valve, the water route entry of technology water set up in waste water import control valve with go into between the atomizer waste water flow measuring apparatu, set up technology water import control valve on the water route of technology water.

It is further characterized in that:

the interface of the flue gas outlet access flue of the drying tower is connected with the inlet front main flue tee of the dust remover;

the drying tower also comprises baffle doors arranged at the inlets and the outlets of all flues of the drying tower;

the baffle door arranged at the smoke inlet of the drying tower is an adjustable baffle door, and the baffle doors on other smoke paths are opening-closing type baffle doors;

the baffle doors are double-layer sealing shutter baffle doors, and the inlet of heating sealing gas for sealing the baffle doors is controlled by an independently arranged sealing air pipeline subsystem;

the sealed air pipeline subsystem comprises a sealed fan and a sealed air pipeline system connected with each baffle door; the sealing fan is connected with the sealing wind power heater through an air pipeline, and sealing gas is heated to be higher than 100 ℃ through the sealing wind power heater and then is input into the sealing layer of the baffle door; the seal air pressure in the flapper door is at least 0.5Kpa higher than the flue gas pressure in the drying tower; a sealing wind pressure tester is arranged between the sealing fan and the sealing wind power heater, and a sealing wind temperature tester is arranged at the outlet of the sealing wind power heater;

the bottom of the drying tower is provided with a crusher and a rapping device;

the body of the drying tower and the flue gas distributor adopt high-temperature-resistant boiler steel and a corrosion-resistant coating.

A control method of a drying system for drying waste water by bypass flue gas is characterized by comprising the following steps:

controlling the inlet amount of wastewater and the inlet amount of flue gas for drying in an interlocking manner: after a wastewater inlet control valve arranged at an atomized wastewater inlet of the rotary atomizer is started, when an inlet atomizer wastewater flow measuring instrument detects that the flow of wastewater entering the rotary atomizer is increased, a controller starts an inlet flue gas control valve and an inlet flue gas temperature measuring instrument which are arranged at a flue gas inlet of a drying tower, and automatically adjusts drying flue gas entering the drying tower according to the increased flow of the wastewater, so that the heat of the drying flue gas is matched with the amount of the wastewater entering the rotary atomizer;

adjusting the water inflow of wastewater and the flue gas inflow through the water content of the outlet flue gas: arranging an outlet flue gas water content tester at a flue gas outlet of the drying tower, and monitoring the outlet flue gas water content in real time; when the water content of the outlet flue gas is higher than a preset outlet flue gas water content threshold value, the controller controls the opening degrees of the wastewater inlet control valve and the inlet flue gas control valve in an interlocking manner, and the water content of the outlet flue gas is controlled by adjusting the water inflow and the flue gas inflow;

adjusting the water inflow of the process water, the wastewater inlet amount for drying and the flue gas inlet amount through the outlet flue gas temperature: an outlet flue gas control valve and an outlet flue gas temperature measuring instrument are arranged at a flue gas outlet of the drying tower, and when the outlet flue gas temperature measuring instrument monitors that the outlet flue gas temperature is lower than a preset flue gas temperature dew point threshold value, the controller controls the opening of the inlet flue gas control valve in an interlocking mode, so that the flue gas quantity is increased, and the outlet flue gas temperature is further increased; when the outlet flue gas temperature measuring instrument monitors that the outlet flue gas temperature is higher than a preset tolerant temperature threshold value of the dust remover, the controller interlockingly increases the opening degrees of a process water inlet control valve and a waste water inlet control valve, so that the amount of water entering the drying tower through the rotary atomizer is increased, and the outlet flue gas temperature is reduced;

controlling corrosion prevention of the drying tower: when the drying tower is started, the controller starts the inlet flue gas temperature measuring instrument to measure the inlet flue gas temperature, and when the inlet flue gas temperature is lower than the flue gas temperature dew point threshold, the controller locks the process water inlet control valve and the wastewater inlet control valve to control the process water inlet control valve and the wastewater inlet control valve to stop starting until the inlet flue gas temperature is higher than the flue gas temperature dew point threshold.

It is further characterized in that:

it still includes: when the drying tower is separated from the main system and stops running, the controller closes a flue damper door at the inlet and the outlet of the system, and simultaneously blows sealing air into the damper door through the sealing air pipeline subsystem; then the controller monitors the temperature of the sealing wind in real time through a sealing wind temperature tester arranged at an outlet of the sealing wind power heater, and once the temperature of the sealing wind is lower than 100 ℃, the sealing wind power heater is started to heat until the temperature is higher than 100 ℃; the controller is through installing on sealed wind pipeline sealed wind pressure tester real-time supervision seals the pressure value of wind, through setting up the inside flue gas pressure value of dry tower is monitored to the flue gas pressure tester in the drying tower, sealed air pressure must keep being higher than flue gas pressure value, when the difference of the two is less than 0.5Kpa, starts sealed fan and increases sealed air pressure is greater than 0.5Kpa until the difference of the two.

The invention provides a drying system and a control method for drying waste water by bypass flue gas, which are characterized in that a measuring instrument is arranged: the system comprises an inlet flue gas temperature measuring instrument, an inlet atomizer waste water flow measuring instrument, an outlet flue gas temperature measuring instrument, an outlet flue gas water content measuring instrument, an outlet flue gas temperature measuring instrument and an outlet flue gas water content measuring instrument, wherein parameters such as temperature, water content and the like of a drying tower are monitored in real time; by using the technical scheme of the invention, manual control is not needed, and uninterrupted operation can be performed through instruments, so that the error probability of the system is greatly reduced.

Drawings

FIG. 1 is a schematic view of a process flow of the bypass flue gas drying wastewater of the present invention;

FIG. 2 is a schematic view of a drying system according to the present invention;

FIG. 3 is a schematic system diagram of an embodiment of a drying system;

fig. 4 is an enlarged schematic view of a portion a.

Detailed Description

The device is used for treating the high-salt-content wastewater treated by the desulfurization wastewater triple-box treatment system, the wastewater mainly contains salt components such as sodium chloride, sodium sulfate, sodium sulfite, potassium chloride, calcium chloride and the like, the drying capacity of the single-line wastewater is less than 15m3/h, and the conductivity of the treated wastewater is less than 150 mS/cm.

As shown in fig. 1 and 2, the present invention includes a drying system for drying wastewater by using bypass flue gas, wherein flue gas discharged from a boiler 1 enters a denitration System (SCR) 2, a drying tower 4 is connected to a flue between the denitration system 2 and an air preheater 5 in the boiler flue system through a total flue gas inlet 4-1 of the drying tower, a flue gas distributor (not shown in the figure) is arranged at the flue gas inlet 4-1 of the drying tower, and a flue gas outlet 4-2 of the drying tower is connected to a dust remover 3; the interface of the flue gas outlet 4-2 of the drying tower connected into the flue is connected with the inlet front main flue tee joint of the dust remover 3, so that the original flow field and dust removal effect of the dust remover are prevented from being influenced, the crystallized salt and ash formed by drying in the drying tower 4 enter the inlet flue of the dust remover 3 along with the outlet flue gas, are uniformly mixed with the main flue gas of the boiler system and enter the dust remover 3, the crystallized salt can be uniformly distributed in the ash, and the problems of caking, blocking and the like cannot occur;

the drying tower 4 atomizes the wastewater by using a rotary atomizer 6; the system is electrically controlled by a controller (not shown) and connected with an electric control device, and the electric control device comprises: the system comprises an inlet flue gas control valve 7 and an inlet flue gas temperature measuring instrument 8 which are arranged at a flue gas inlet 4-1 of a drying tower, an outlet flue gas control valve 12, an outlet flue gas temperature measuring instrument 13 and an outlet flue gas water content measuring instrument 14 which are arranged at a flue gas outlet 4-2 of the drying tower, a waste water inlet control valve 9 which is arranged at an atomized waste water inlet 4-4 of the drying tower, an atomizer waste water flow measuring instrument 10 which is arranged between the atomized waste water inlet 4-4 of the drying tower and the waste water inlet control valve 9, a waterway inlet of process water which is arranged between the waste water inlet control valve 9 and the atomizer waste water flow measuring instrument 10, and a process water inlet control valve 11 which is arranged on a waterway of the.

As shown in fig. 3 and 4 of the attached drawings of the specification, fig. 3 and 4 are an embodiment of the technical scheme of the invention, wherein a drying tower flue gas outlet 4-2 of a drying tower 4 is connected with an inlet front main flue tee joint of a dust remover 3 through a flue gas pipeline interface 17; a flue gas inlet 4-1 of the drying tower is connected with a flue between a denitration system 2 and an air preheater 5 in a boiler flue gas system through a flue gas pipeline interface 21, and a flue gas pressure tester 22 is arranged on a flue gas passage to detect the pressure value of the drying flue gas in the drying tower 4 in real time; the drying tower atomized wastewater inlet 4-4 is connected with a water channel of process water through a water channel interface 19 and is connected to a water channel of high-salt-content wastewater through a water channel interface 21; the drying system also includes a damper 16 disposed at the inlet and outlet of all of the flues of the drying tower; the flue gas inlet 4-1 of the drying tower is a main flue gas inlet of the drying tower, a damper arranged at the flue gas inlet 4-1 of the drying tower is an adjustable damper, and the amount of flue gas entering the system is adjusted according to the outlet flue temperature of the spray drying system; the baffle doors on other smoke paths are opening-closing type baffle doors; the baffle door 16 adopts a double-layer sealing shutter baffle door, and the inlet of heating sealing gas for the double-layer sealing shutter baffle door is controlled by an independently arranged sealing air pipeline subsystem 15; the sealed air duct subsystem 15 includes a sealed fan 15-1, a sealed air duct system 15-5 connected to each flapper door 16; the sealing fan 15-1 is connected with the sealing wind power heater 15-2 through an air pipeline, and sealing gas is heated to be higher than 100 ℃ through the sealing wind power heater 15-1 and then is input into a sealing layer of the baffle door 16; the sealing air pressure in flapper door 16 is at least 0.5Kpa higher than the flue gas pressure in drying tower 4; a sealing wind pressure tester 15-4 is arranged between the sealing fan 15-1 and the sealing wind power heater 15-2, and a sealing wind temperature tester 15-3 is arranged at the outlet of the sealing wind power heater 15-2; the temperature of the sealing air is monitored at any time through the sealing air temperature tester 15-3, and the automatic control of the sealing air pipeline subsystem 15 is realized according to the change of the temperature.

A crusher 18 and a rapping device (not shown in the figure) are arranged below a waste residue outlet 4-3 at the bottom of the drying tower 4; the collection rate of the dry miscellaneous salt at the bottom of the device cannot exceed 20 percent of the total content in the wastewater, mainly particulate matters with the particle size larger than 30 mu m are collected from the bottom of the drying tower, the rest are collected by a subsequent dust remover, and the more miscellaneous salt collected by the drying tower, the poorer atomization effect is shown, and the lower drying efficiency is; the bottom of the tower is provided with a crusher and a rapping device, so that the miscellaneous salt can be prevented from caking or can pass through a crushing discharge system after caking;

the body of the drying tower 4 and the flue gas distributor adopt high temperature resistant boiler steel and a corrosion resistant coating, so that the probability of damage of the equipment in the using process is reduced.

The detailed content of the control method of the drying system for drying the wastewater by the bypass flue gas based on the technical scheme of the invention is shown as follows.

Controlling the inlet amount of wastewater and the inlet amount of flue gas for drying in an interlocking manner: after a wastewater inlet control valve 9 arranged at an atomized wastewater inlet 4-4 of a rotary atomizer 6 is started, when an inlet atomizer wastewater flow measuring instrument 10 detects that the flow of wastewater entering the rotary atomizer 6 is increased, a controller (not shown in the figure) starts an inlet flue gas control valve 7 and an inlet flue gas temperature measuring instrument 10 which are arranged at a flue gas inlet 4-1 of a drying tower 4, and automatically adjusts the drying flue gas entering the drying tower 4 according to the increased flow of wastewater, so that the heat of the drying flue gas is matched with the flow of wastewater entering the rotary atomizer 6; the drying tower 4 is ensured to be capable of accurately and automatically performing the operation of the drying process.

Adjusting the water inflow of wastewater and the flue gas inflow through the water content of the outlet flue gas: arranging an outlet flue gas water content tester 14 at a flue gas outlet 4-2 of the drying tower, and monitoring the outlet flue gas water content in real time; when the water content of the outlet flue gas is higher than a preset outlet flue gas water content threshold value (set to 25% in the embodiment), the controller controls the opening degrees of the wastewater inlet control valve 9 and the inlet flue gas control valve 7 in an interlocking manner, and the water content of the outlet flue gas is controlled by adjusting the water inflow and the flue gas inflow;

adjusting the water inflow of the process water, the wastewater inlet amount for drying and the flue gas inlet amount through the outlet flue gas temperature: an outlet flue gas control valve 12 and an outlet flue gas temperature measuring instrument 13 are arranged at the flue gas outlet 4-2 of the drying tower, and when the outlet flue gas temperature measuring instrument 13 monitors that the outlet flue gas temperature is lower than a preset flue gas temperature dew point threshold (150 ℃ is set in the embodiment), the controller controls the opening of the inlet flue gas control valve 7 in an interlocking manner, so that the flue gas volume is increased, and the outlet flue gas temperature is further increased; when the outlet flue gas temperature measuring instrument 13 monitors that the outlet flue gas temperature is higher than a preset tolerant temperature threshold value of the dust remover, the controller interlockingly increases the opening degrees of the process water inlet control valve 11 and the wastewater inlet control valve 9, so that the water amount entering the drying tower 4 through the rotary atomizer 6 is increased, namely, the outlet flue gas temperature is reduced by increasing the water amounts of the process water and the wastewater for drying;

once the temperature of the flue gas discharged from the drying tower 4 is lower than 150 ℃ or the water content is higher than 25%, acid dew is formed, corrosion is generated on a subsequent dust remover, and equipment damage is caused; according to the technical scheme, the controller is used for adjusting the wastewater inlet amount and the drying flue gas amount entering the drying tower based on the temperature of the discharged flue gas and the threshold value of the water content, so that the temperature and the water content of the discharged flue gas are ensured to be in a safe range, and the probability of equipment loss is reduced.

Controlling corrosion prevention of the drying tower: when the drying tower 4 is started, the controller starts the inlet flue gas temperature measuring instrument 10 to measure the inlet flue gas temperature, and when the inlet flue gas temperature is lower than a flue gas temperature dew point threshold (150 ℃ is set in the embodiment), the controller locks the process water inlet control valve 11 and the wastewater inlet control valve 9, and controls the process water inlet control valve 11 and the wastewater inlet control valve 9 to stop starting until the inlet flue gas temperature is higher than the flue gas temperature dew point threshold;

when the temperature of the inlet flue gas is lower than the flue gas temperature dew point threshold value by 150 ℃, acid dew can be generated, the controller locks the process water inlet control valve 11 and the wastewater inlet control valve 9 at the moment, and the drying tower 4 is ensured not to enter process water or desulfurization wastewater, so that the drying tower is protected from being corroded, and the probability of equipment damage is reduced.

When the drying tower 4 is separated from the main system and stops running, the controller closes the flue damper door at the inlet and the outlet of the system, and simultaneously blows sealing air into the damper door through the sealing air pipeline subsystem; the controller monitors the temperature of the sealing wind in real time through a sealing wind temperature tester 15-3 arranged at an outlet of the sealing wind power heater 15-2, and once the temperature of the sealing wind is lower than 100 ℃, the sealing wind power heater 15-2 is started to heat until the temperature is higher than 100 ℃; the controller monitors the pressure value of the sealing air in real time through the sealing air pressure tester 15-4, monitors the smoke pressure value inside the drying tower through the smoke pressure tester 22 arranged in the drying tower 4, the sealing air pressure is required to be kept higher than the smoke pressure value, and when the difference between the two is smaller than 0.5Kpa, the sealing fan 15-1 is started to increase the sealing air pressure until the difference between the two is larger than 0.5 Kpa.

According to the technical scheme, the drying system is completely isolated from the boiler system and operates independently, and hot flue gas in front of an air preheater after denitration of the boiler is used as a heat source; the treatment capacity of the wastewater for drying is adjusted according to the load and the operation condition of the host, and the stable operation of the drying system, an upstream unit (a boiler system) and a downstream unit (a dust remover) is ensured by performing interlocking control on the temperature of the flue gas at the inlet and the outlet of the drying tower, the moisture content of the flue gas at the outlet and the amount of the flue gas; the system not only realizes the automatic operation of the system, but also can adjust the operation of the system according to the real-time condition of the system, thereby reducing the probability of equipment damage and improving the operation stability of the whole system.