Residual hydrogen peroxide monitoring and removing system and method

Abstract

The invention belongs to the technical field of condensate polishing of direct air cooling units, and discloses a residual hydrogen peroxide monitoring and removing system and method, and the system comprises a residual removing subsystem and a monitoring subsystem; the residue removing subsystem is used for removing residual hydrogen peroxide in the condensed water, the first catalytic reactor and the cooler, and the monitoring subsystem is used for monitoring the residual hydrogen peroxide in the condensed water in real time; the residue removal subsystem comprises a low-pressure heater; a cold side inlet of the low-pressure heater is connected with an outlet of the condensed water collecting tank, a cold side outlet of the low-pressure heater is connected with an inlet of the first catalytic reactor, an outlet of the first catalytic reactor is connected with a hot side inlet of the cooler, and a hot side outlet of the cooler is used for being connected with an inlet of the fine treatment mixed bed; the residual hydrogen peroxide can be monitored in real time while the residual hydrogen peroxide is removed, so that the residual hydrogen peroxide in the direct air-cooled condenser is effectively reduced, and the operation safety of thermal equipment of a unit is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of condensate polishing of direct air-cooling units, and in particular relates to a residual hydrogen peroxide monitoring and removal system and method. Background Art

[0002] Direct air-cooled condensers are surface heat exchangers that use air as a cooling medium to directly cool turbine exhaust steam into condensate. Most existing direct air-cooled condensers are made of carbon steel, and the phenomenon of flow-accelerated corrosion of carbon steel parts is common during their operation. At present, a treatment process that uses a dosing system to add an oxidant to the main exhaust pipe is usually used to fundamentally inhibit the flow-accelerated corrosion of carbon steel parts in the air-cooled island of gas-liquid two-phase flow. Oxidants, such as hydrogen peroxide, are highly oxidizing and corrosive. Although they decompose into oxygen and water during use, due to the fast exhaust flow rate and large amount of condensate of the direct air-cooled condenser, the added hydrogen peroxide cannot be completely decomposed in a short time, resulting in a large amount of residual hydrogen peroxide in the air-cooled island system.

[0003] On the one hand, residual hydrogen peroxide will affect the performance and service life of the mixed bed anion and cation exchange resins for condensate polishing. On the other hand, entering the water vapor system of the unit will accelerate the oxidation reaction of the cobalt-based Stellite alloy on the sealing surface of the high-temperature and high-pressure valve, resulting in the thickening of the oxide scale and even excessive oxidation, causing the valve to stick, thereby reducing the operating efficiency of the unit. At present, the concentration of hydrogen peroxide in the exhaust steam of the direct air-cooled condenser treated with chemicals is generally 1-2 mg / L. After entering the air-cooled island system and being decomposed, the hydrogen peroxide has generally dropped to below 1 mg / L. However, traditional hydrogen peroxide monitoring methods cannot achieve accurate detection of low-concentration hydrogen peroxide, and cannot remove the detected low-concentration hydrogen peroxide. Summary of the invention

[0004] In view of the technical problems existing in the prior art, the present invention provides a residual hydrogen peroxide monitoring and removal system and method to solve the technical problems that traditional hydrogen peroxide monitoring means cannot accurately detect low-concentration hydrogen peroxide and cannot remove the detected low-concentration hydrogen peroxide.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a residual hydrogen peroxide monitoring and removal system, comprising a residual removal subsystem and a monitoring subsystem; the residual removal subsystem is used to remove residual hydrogen peroxide in condensate water, and the residual removal subsystem comprises a low-pressure heater, a first catalytic reactor and a cooler; The cold side inlet of the low-pressure heater is connected to the outlet of the condensate collecting tank, the cold side outlet of the low-pressure heater is connected to the inlet of the first catalytic reactor, the outlet of the first catalytic reactor is connected to the hot side inlet of the cooler, and the hot side outlet of the cooler is used to be connected to the inlet of the fine treatment mixed bed; wherein the last stage extraction steam of the low-pressure cylinder of the steam turbine is introduced into the low-pressure heater as a heating source; The monitoring subsystem is used for real-time monitoring of residual hydrogen peroxide in condensate water; wherein, the monitoring subsystem is provided with two sampling inlets, the first sampling inlet is connected to a first preset sampling point, and the second sampling inlet is connected to a second preset sampling point; the first preset sampling point is located between the condensate collecting tank and the low-pressure heater, and the second preset sampling point is located between the cooler and the fine treatment mixed bed.

[0006] Furthermore, the residual removal subsystem also includes an electric main valve, an electric bypass valve and a second catalytic reactor; the electric main valve is arranged between the cooler and the fine treatment mixed bed; after the electric bypass valve is connected in series with the second catalytic reactor, it is connected in parallel with the electric main valve between the cooler and the fine treatment mixed bed.

[0007] Furthermore, the monitoring subsystem includes an electromagnetic four-way valve, a detection pool and a detector; port b of the electromagnetic four-way valve is connected to the first preset sampling point, and port c of the electromagnetic four-way valve is connected to the second preset sampling point; port d of the electromagnetic four-way valve is connected to the water sample inlet of the detection pool, and the detector is arranged at a preset position of the detection pool; wherein, the detector is used to detect the absorbance of the water sample in the detection pool in real time.

[0008] Furthermore, the monitoring subsystem also includes a detection reagent storage tank, a reagent shut-off valve, a reagent feed pump and a reagent quantitative ring; The detection reagent storage tank stores detection reagent, the outlet of the detection reagent storage tank is connected to the inlet of the reagent shut-off valve, the outlet of the reagent shut-off valve is connected to the inlet of the reagent feed pump, the outlet of the reagent feed pump is connected to the inlet of the reagent quantitative ring, and the outlet of the reagent quantitative ring is connected to the reagent inlet of the detection cell.

[0009] The detection reagent storage tank stores detection reagents, the outlet of the detection reagent storage tank is connected to the inlet of the reagent feeding pump, the outlet of the reagent feeding pump is connected to the inlet of the reagent quantitative ring, and the outlet of the reagent quantitative ring is connected to the reagent inlet of the detection cell.

[0010] Furthermore, the monitoring subsystem also includes a desalted water storage tank and a desalted water flushing pump; The desalted water storage tank stores desalted water, the outlet of the desalted water storage tank is connected to the inlet of the desalted water flushing pump, and the outlet of the desalted water flushing pump is connected to the port a of the electromagnetic four-way valve.

[0011] Furthermore, the monitoring subsystem also includes a first electric sampling valve, a second electric sampling valve, a first injection pump and a second injection pump; The first electric sampling valve and the first sampling pump are connected in series between the first preset sampling point and the port b of the electromagnetic four-way valve; the second electric sampling valve and the second sampling pump are connected in series between the second preset sampling point and the port c of the electromagnetic four-way valve.

[0012] Furthermore, it also includes a control subsystem; the control subsystem includes a display and an automatic controller; The display has a human-computer interaction function, and is used to receive system operation parameters sent by the user, and send the system operation parameters to the residual removal subsystem and the monitoring subsystem; and is also used to display the absorbance of the water sample in the detection pool detected in real time; The automatic controller is used to compare the absorbance of the water sample in the detection pool detected in real time with a preset water sample absorbance threshold, and generate and send system operation instructions to the residual removal subsystem and the monitoring subsystem based on the comparison results; it is also used to generate and send dosing control instructions to the dosing system based on the comparison results.

[0013] Furthermore, the detection reagent is a mixture of 3-aminophthalhydrazide and sodium hydroxide; and the detector is an ultraviolet spectrophotometer.

[0014] Furthermore, the first catalytic reactor is filled with an iron catalyst, and the second catalytic reactor is filled with a nano manganese dioxide catalyst.

[0015] The present invention also provides a residual hydrogen peroxide monitoring and removal method, using the residual hydrogen peroxide monitoring and removal system; Wherein, the residual hydrogen peroxide monitoring and removal method comprises: The residual hydrogen peroxide in the condensate water is removed by using the residual removal subsystem; The residual hydrogen peroxide in the condensate water is monitored in real time by using the monitoring subsystem; wherein, the operating state of the residual removal subsystem and the dosing system are adjusted according to the real-time monitoring result of the monitoring subsystem.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The residual hydrogen peroxide monitoring and removal system provided by the present invention utilizes a residual removal subsystem to eliminate residual hydrogen peroxide, and utilizes a monitoring subsystem to monitor hydrogen peroxide on condensate at a preset sampling point in the residual removal subsystem, so that while achieving residual hydrogen peroxide removal, the residual hydrogen peroxide can be monitored in real time, effectively reducing the residual hydrogen peroxide in the direct air-cooled condenser, and fully ensuring the operating safety of the unit thermal equipment; wherein, a low-pressure heater is introduced into the residual removal subsystem, and the last-stage extraction steam of the low-pressure cylinder of the turbine is introduced into the low-pressure heater, so as to increase the condensate temperature to above 70°C, which is much higher than the decomposition temperature of hydrogen peroxide, and can increase the decomposition of hydrogen peroxide; secondly, by introducing a catalytic reactor, the decomposition of hydrogen peroxide can be greatly accelerated, ensuring that the condensate is completely decomposed before entering the fine treatment mixed bed; in addition, by introducing a cooler, the temperature of the condensate can be reduced, avoiding the influence of high-temperature condensate on the fine treatment mixed bed.

[0017] Furthermore, by introducing the second catalytic reactor, the decomposition efficiency of hydrogen peroxide can be improved and accelerated, effectively ensuring that the condensate is completely decomposed before entering the fine treatment high-speed mixed bed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a structural block diagram of the residual hydrogen peroxide monitoring and removal system provided in Example 1.

[0019] Among them, 1 is a low-pressure heater, 2 is a first catalytic reactor, 3 is a cooler, 4 is an electric main valve, 5 is a fine treatment mixed bed, 6 is a low-pressure cylinder of a steam turbine; 7 is an electric bypass valve, 8 is a second catalytic reactor; 9 is a first electric sampling valve, 10 is a second electric sampling valve; 11 is a first sampling pump, 12 is a second sampling pump, 13 is an electromagnetic four-way valve, 14 is a sample quantitative loop, 15 is a detection cell, 16 is a detector; 17 is a detection reagent storage tank, 18 is a reagent shut-off valve, 19 is a reagent feed pump, 20 is a reagent quantitative loop; 21 is a desalted water storage tank, 22 is a desalted water inlet shut-off valve, 23 is a desalted water flushing pump; 24 is an electric drain valve; 25 is a control cabinet, 26 is a display, 27 is an automatic controller; 28 is a condensate collecting tank, 29 is a main exhaust steam pipeline, and 30 is a dosing system. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail in the following specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] Example 1 As attached Figure 1As shown, this embodiment 1 provides a residual hydrogen peroxide monitoring and removal system, including a residual removal subsystem, a monitoring subsystem and a control subsystem; the residual removal subsystem is arranged between the condensate collecting tank 28 and the fine treatment mixed bed 5, and is used to remove the residual hydrogen peroxide in the condensate; the monitoring subsystem is used to perform real-time monitoring of the residual hydrogen peroxide in the condensate; the control subsystem is used to automatically control the residual removal subsystem, the monitoring subsystem and the dosing system.

[0022] In this embodiment 1, the residual removal subsystem includes a low-pressure heater 1 , a first catalytic reactor 2 , a cooler 3 , an electric main valve 4 , an electric bypass valve 7 and a second catalytic reactor 8 .

[0023] The cold side inlet of the low-pressure heater 1 is connected to the outlet of the condensate collecting tank 28, the cold side outlet of the low-pressure heater 1 is connected to the inlet of the first catalytic reactor 2, the outlet of the first catalytic reactor 2 is connected to the hot side inlet of the cooler 3, and the hot side outlet of the cooler 3 is used to be connected to the inlet of the fine treatment mixed bed 5; wherein, the last stage extraction steam of the low-pressure cylinder 6 of the steam turbine is introduced into the low-pressure heater 1 as a heating source; specifically, the hot side inlet of the low-pressure heater 1 is connected to the outlet of the low-pressure cylinder 6 of the steam turbine, and the hot side outlet of the low-pressure heater 1 is used to be connected to the inlet of the hydrophobic recovery system; preferably, the first catalytic reactor 2 is filled with iron catalyst.

[0024] It should be noted that the inlet of the condensate collecting tank 28 is connected to the main exhaust steam pipe 29, which is used to collect and store the condensate in the main exhaust steam pipe 29; wherein, a dosing system 30 is provided in the main exhaust steam pipe 29, which is used to add hydrogen peroxide to the direct air-cooled condenser; specifically, the dosing system 30 is connected to the main exhaust steam pipe 29 through a dosing pipeline, and the main exhaust steam pipe 29 is connected to the condensate collecting tank 28; the turbine low-pressure cylinder 6 is connected to the low-pressure heater 1 through a steam extraction system; wherein, the high-temperature steam in the turbine low-pressure cylinder 6 enters the low-pressure heater 1 to heat the condensate from the condensate collecting tank 28, and the condensed steam forms drain and returns to the drain recovery system.

[0025] The cooler 3 is used to cool the condensate heated by the low-pressure heater 1 and flowing through the first catalytic reactor 2, on the one hand to reduce the catalytic reaction temperature to achieve safety, on the other hand to reduce the impact of high temperature on the resin in the fine treatment mixed bed 5.

[0026] The electric main valve 4 is arranged between the cooler 3 and the fine treatment mixed bed 5; the electric bypass valve 7 is connected in series with the second catalytic reactor 8, and then connected in parallel with the electric main valve 4 between the cooler 3 and the fine treatment mixed bed 5; specifically, the outlet of the cooler 3 is arranged in two ways, one of which is connected to the inlet of the electric main valve 4, and the other is connected to the inlet of the electric bypass valve 7; the outlet of the electric main valve 4 is connected to the inlet of the fine treatment mixed bed 5; the outlet of the electric bypass valve 7 is connected to the inlet of the second catalytic reactor 8, and the outlet of the second catalytic reactor 8 is connected to the inlet of the fine treatment mixed bed 5; the outlet of the fine treatment mixed bed 5 is connected to the inlet of the deaerator; preferably, the second catalytic reactor 8 is filled with nano manganese dioxide catalyst.

[0027] In this embodiment 1, the monitoring subsystem is provided with two sampling inlets; wherein, the first sampling inlet is connected to the first preset sampling point, and the second sampling inlet is connected to the second preset sampling point; the first preset sampling point is located between the condensate collecting tank 28 and the low-pressure heater 1, and the second preset sampling point is located between the cooler 3 and the fine treatment mixed bed 5; wherein, the second preset sampling point is arranged close to one end of the fine treatment mixed bed 5.

[0028] The monitoring subsystem includes a first electric sampling valve 9, a second electric sampling valve 10, a first sampling pump 11, a second sampling pump 12, an electromagnetic four-way valve 13, a sample quantitative loop 14, a detection cell 15, a detector 16, a detection reagent storage tank 17, a reagent shut-off valve 18, a reagent feed pump 19, a reagent quantitative loop 20, a deionized water storage tank 21, a deionized water inlet shut-off valve 22, a deionized water flushing pump 23 and an electric drain valve 24.

[0029] The first electric sampling valve 9 is connected to the first preset sampling point between the condensate collecting tank 28 and the low-pressure heater 1; the second electric sampling valve is connected to the second preset sampling point between the electric main valve 4 and the fine treatment mixed bed 5; the reagent shut-off valve 18 is connected to the outlet of the detection reagent storage tank 17 and the inlet of the reagent feed pump 19 through pipelines; the reagent feed pump 19 is connected to the reagent quantitative ring 20 through a pipeline, and the reagent quantitative ring 20 is connected to the detection pool 15 through a pipeline; the first feed pump 11 is connected to the electromagnetic four-way valve through a pipeline. 13 is connected to port b, the second sampling pump 12 is connected to port c of the electromagnetic four-way valve 13 through a pipeline, and port d of the electromagnetic four-way valve 13 is connected to the sample quantitative loop 14 through a pipeline; the desalted water inlet shut-off valve 22 is connected to the outlet of the desalted water storage tank 21 and the inlet of the desalted water flushing pump 23 through a pipeline, and the desalted water flushing pump 23 is connected to port a of the electromagnetic four-way valve 13; the sample quantitative loop 14 is connected to the detection cell 15; the detection cell 15 is connected to the electric drain valve 24 through a pipeline.

[0030] Specifically, the inlet of the first electric sampling valve 9 is connected to the first preset sampling point, the outlet of the first electric sampling valve 9 is connected to the inlet of the first sampling pump 11, and the outlet of the first sampling pump 11 is connected to the port b of the electromagnetic four-way valve 13; that is, the first electric sampling valve 9 and the first sampling pump 11 are connected in series between the first preset sampling point and the port b of the electromagnetic four-way valve 13 in sequence to connect the first preset sampling point with the port b of the electromagnetic four-way valve 13; the inlet of the second electric sampling valve 10 is connected to the second preset sampling point, and the outlet of the second electric sampling valve 10 is connected to the inlet of the first sampling pump 11. The outlet of the electric sampling valve 10 is connected to the inlet of the second sampling pump 12, and the outlet of the second sampling pump 12 is connected to the port c of the electromagnetic four-way valve 13; that is, the second electric sampling valve 10 and the second sampling pump 12 are connected in series between the second preset sampling point and the port c of the electromagnetic four-way valve 13 in sequence to connect the second preset sampling point with the port c of the electromagnetic four-way valve 13; preferably, the first sampling pump 11 and the second sampling pump 12 both adopt a constant flow pump with a volume flow rate continuously adjustable in the range of 0.05-20mL / s, and have a double plunger structure.

[0031] The port d of the electromagnetic four-way valve 13 is connected to the inlet of the sample quantitative ring 14, and the outlet of the sample quantitative ring 14 is connected to the water sample inlet of the detection pool 15; the detector 16 is arranged at a preset position of the detection pool 15, and is used to detect the absorbance of the water sample in the detection pool 15 in real time; preferably, the detection pool 15 adopts a quartz cuvette, and the quartz cuvette has an outer dimension of 12.5×102.5×45mm; the detector 16 is an ultraviolet spectrophotometer, and the ultraviolet full wavelength scanning range of the ultraviolet spectrophotometer is between 190-400nm, so as to continuously detect the absorbance value of the water sample; the sample quantitative ring 14 adopts a stainless steel or PEEK quantitative ring.

[0032] The detection reagent storage tank 17 stores the detection reagent for light-proof storage of the detection reagent; preferably, the detection reagent storage tank 17 is a cylindrical brown glass container with a scale; the detection reagent is a mixture of 3-aminophthalhydrazide and sodium hydroxide; wherein the concentration of 3-aminophthalhydrazide is 1.0mmol / L, and the concentration of sodium hydroxide is 0.05mmol / L; the outlet of the detection reagent storage tank 17 is connected to the inlet of the reagent shut-off valve 18, the outlet of the reagent shut-off valve 18 is connected to the inlet of the reagent drug feed pump 19, the outlet of the reagent drug feed pump 19 is connected to the inlet of the reagent quantitative ring 20, and the outlet of the reagent quantitative ring 20 is connected to the reagent inlet of the detection cell 15; preferably, the reagent quantitative ring 20 is a stainless steel or PEEK quantitative ring.

[0033] The desalted water storage tank 20 is a storage tank made of plexiglass, and desalted water is stored in the desalted water storage tank 20; the outlet of the desalted water storage tank 21 is connected to the inlet of the desalted water inlet shut-off valve 22, the outlet of the desalted water inlet shut-off valve 22 is connected to the inlet of the desalted water flushing pump 23, and the outlet of the desalted water flushing pump 23 is connected to the port a of the electromagnetic four-way valve 13; wherein the desalted water flushing pump 23 adopts a constant flow pump with a volume flow rate continuously adjustable in the range of 0.05-50mL / s.

[0034] A sewage outlet is provided at the bottom of the side of the detection pool 15, and the electric sewage valve 24 is arranged at the sewage outlet; wherein, the inlet of the electric sewage valve 24 is connected to the sewage outlet, and the outlet of the electric sewage valve 24 is used to be connected to a sewage storage device.

[0035] In this embodiment 1, the control subsystem includes a control cabinet 25, a display 26 and an automatic controller 27; the control cabinet 25 adopts a control cabinet structure made of stainless steel, and the control cabinet 25 is connected to a 220 AC power supply through a power adapter; the first sampling pump 11, the second sampling pump 12, the electromagnetic four-way valve 13, the sample quantitative ring 14, the detection cell 15, the detector 16, the reagent quantitative ring 20, the deionized water flushing pump 23 and the electric drain valve 24 are all arranged inside the control cabinet 25, the display 26 is arranged on one side of the top of the control cabinet 25, and the automatic controller 27 is arranged on the other side of the top of the control cabinet 25.

[0036] The display 26 has a human-computer interaction function, which is used to receive system operating parameters sent by the user and send the system operating parameters to the residual removal subsystem and the monitoring subsystem; it is also used to display the absorbance of the water sample in the detection pool 15 detected in real time; the automatic controller 27 is used to compare the absorbance of the water sample in the detection pool 15 detected in real time with a preset water sample absorbance threshold, and generate and send system operating instructions to the residual removal subsystem and the monitoring subsystem according to the comparison results; it is also used to generate and send dosing control instructions to the dosing system according to the comparison results.

[0037] Specifically, the display 26 includes a human-computer interaction interface and a display interface, and the automatic controller 27 includes a control module and a threshold judgment module; preferably, the display 26 is one of LCD, LED or OLED; the automatic controller 27 adopts a controller including a PLC control module and a PLC judgment module.

[0038] The human-computer interaction interface is used to receive system operating parameters sent by the user, and send the system operating parameters to the corresponding equipment through the control module; wherein the system operating parameters include the flushing flow of the desalted water flushing pump 23, the flushing time of the desalted water flushing pump 23, the flow of the first sampling pump 11, the flow of the second sampling pump 12, the flow of the reagent drug feed pump 19, the absorption wavelength of the detector 16 and the preset water sample absorbance threshold; specifically, the flushing flow of the desalted water flushing pump 23 and the flushing time of the desalted water flushing pump 23 are sent to the desalted water flushing pump 23, the flow of the first sampling pump 11 is sent to the first sampling pump 11, the flow of the second sampling pump 12 is sent to the second sampling pump 12, the flow of the reagent drug feed pump 19 is sent to the reagent drug feed pump 19, and the absorption wavelength of the detector 16 is sent to the detector, so as to control the desalted water flushing pump 23, the first sampling pump 11, the second sampling pump 12, the reagent drug feed pump 19 and the detector 16 to operate according to the preset operating parameters; at the same time, the preset water sample absorbance threshold is sent to the threshold judgment module for threshold comparison.

[0039] The display interface is connected to the output end of the detector 16, and is used to receive and display the absorbance of the water sample in the detection pool 15 detected in real time by the detector 16; the display interface is also connected to the input end of the threshold judgment module, and is used to forward the absorbance of the water sample in the detection pool 15 detected in real time by the detector 16 to the threshold judgment module.

[0040] The control module and the human-computer interaction interface, the threshold judgment module, the electric main valve 4, the electric bypass valve 7, the first electric sampling valve 9, the second electric sampling valve 10, the first sampling pump 11, the second sampling pump 12, the electromagnetic four-way valve 13, the detector 16, the reagent shut-off valve 18, the reagent feed pump 19, the deionized water inlet shut-off valve 22, the deionized water flushing pump 23 and the electric drain valve 24 are used to control the deionized water flushing pump 23, the reagent feed pump 19, the sampling pump, the electromagnetic four-way valve 13, all the electric valves and the electric drain valve 24 based on the system operating parameters sent by the human-computer interaction interface.

[0041] The threshold judgment module is used to compare the absorbance of the water sample in the detection pool 15 detected in real time with the preset water sample absorbance threshold; generate a device control instruction based on the size comparison result, and send the device control instruction to the corresponding device through the control module; and generate and send a dosing control instruction to the dosing system 30 based on the comparison result.

[0042] In this embodiment 1, the system operating parameters are input online in the human-computer interaction interface to control the desalted water flushing pump, reagent feed pump, sample injection pump, electromagnetic four-way valve, all electric valves and electric drain valve; serial port communication can also be performed through the serial port server to send a notification that the residual hydrogen peroxide concentration is too high and reduce the front-end dosing; the electromagnetic four-way valve 13 can freely switch the valve inlet position by the automatic controller 27.

[0043] The residual hydrogen peroxide monitoring and removal system described in Example 1 utilizes a residual removal subsystem to remove residual hydrogen peroxide, and utilizes a monitoring subsystem to monitor hydrogen peroxide in condensate at preset sampling points in the residual removal subsystem, so that abnormal changes in the residual hydrogen peroxide content can be monitored in real time without the need for personnel on duty, and has the characteristics of being simple in structure, automated, efficient, and having a long commissioning time. By real-time monitoring of the abnormality of hydrogen peroxide in condensate and being able to completely eliminate hydrogen peroxide in a timely manner, the safe operation of the thermal equipment of the unit can be effectively guaranteed.

[0044] In this embodiment 1, by introducing a low-pressure heater 1, the final stage extraction steam of the low-pressure cylinder 6 of the steam turbine is introduced into the low-pressure heater 1 to increase the temperature of the condensate to above 70°C; since the increased temperature is much higher than the decomposition temperature of hydrogen peroxide, the decomposition of hydrogen peroxide can be increased; by introducing the first catalytic reactor 2 and the second catalytic reactor 8, a two-stage catalytic reaction is formed, and the two-stage catalytic reaction uses iron catalyst and nano manganese dioxide as fillers respectively, and the large contact area of ​​the fillers is used to greatly accelerate the decomposition of hydrogen peroxide, ensuring that the condensate is completely decomposed before entering the fine treatment mixed bed 5; by introducing a cooler 3 to reduce the temperature of the condensate, the influence of high-temperature condensate on the fine treatment mixed bed 5 is avoided; 3-aminophthalhydrazide is used as a detection agent, which has the advantages of good response and high sensitivity.

[0045] Example 2 This embodiment 2 provides a residual hydrogen peroxide monitoring and removal method, using the residual hydrogen peroxide monitoring and removal system described in the above embodiment 1; wherein the residual hydrogen peroxide monitoring and removal method includes: using a residual removal subsystem to remove residual hydrogen peroxide in condensate water; using a monitoring subsystem to perform real-time monitoring of residual hydrogen peroxide in condensate water; wherein, according to the real-time monitoring results of the monitoring subsystem, the operating state of the residual removal subsystem and the dosing system are adjusted.

[0046] Specifically, the residual hydrogen peroxide monitoring and removal method comprises the following steps: Step 1. Input the system operating parameters through the human-computer interaction interface to set the flow rate of the desalted water flushing pump 23 to 20-30 mL / s, the flushing time of the desalted water flushing pump 23 to 0.5-1 min, the flow rates of the first injection pump 11 and the second injection pump 12 to 5-10 mL / s, the flow rate of the reagent injection pump 19 to 5-10 mL / s, the absorption wavelength of the detector 16 to 200-400 nm, and the preset water sample absorbance threshold to 0-1.0.

[0047] Step 2, the desalted water inlet shut-off valve 22 is opened, the infusion inlet of the electromagnetic four-way valve 13 is switched to port a, the desalted water flushing pump 23 is started, and the pipeline, quantitative loop and detection tank 15 are flushed according to the flow rate and flushing time set in the human-machine interface; the electric drain valve 24 is opened, and the flushing liquid is discharged through the drain port of the detection tank 15. After the flushing is completed, the desalted water inlet shut-off valve 22 is closed.

[0048] Step 3, after executing the above step 2, the reagent shut-off valve 18 is opened, the reagent feeding pump 19 is started, and after the detection reagent enters the detection pool 15 through the reagent quantitative ring 20, the reagent feeding pump 19 is closed; at the same time, the first electric sampling valve 9 is opened, the first sampling pump 11 is started, and the electromagnetic four-way valve 13 switches the infusion inlet to port b. Under the action of the first sampling pump 11, the water sample at the first preset sampling point enters the detection pool 15 through the sample quantitative ring 14; after the water sample enters the detection pool 15, the first electric sampling valve 9 is closed, and the first sampling pump 11 is closed; at this time, the detector 16 outputs the absorbance of the water sample to the display interface in real time online; at the same time, the water The absorbance test value of the sample is fed back to the threshold judgment module, and the absorbance of the water sample in the detection pool 15 detected in real time is compared with the preset water sample absorbance threshold; when the absorbance of the water sample is greater than the preset water sample absorbance threshold, it can be judged that the residual hydrogen peroxide is high; wherein, when the absorbance of the water sample exceeds the preset water sample absorbance threshold, it is judged that the residual hydrogen peroxide exceeds the limit value, and at this time, the condensate flowing out of the cooler 3 enters the fine treatment mixed bed 5 after passing through the electric bypass valve 7 and the second catalytic reactor 8; when the absorbance of the water sample is lower than the preset water sample absorbance threshold, the condensate flowing out of the cooler 3 directly passes through the electric main valve 4 and enters the fine treatment mixed bed 5.

[0049] Step 4: When the absorbance of the water sample exceeds the preset water sample absorbance threshold, the electromagnetic four-way valve 13 switches the infusion inlet to port a, and performs the operation of step 2 to flush the detection pool 15 and the pipeline equipment; After flushing, the second electric sampling valve 10 is opened, the second sampling pump 12 is started, and the electromagnetic four-way valve 13 switches the infusion inlet to port c; under the action of the second sampling pump 12, the water sample enters the detection pool 15 through the sample quantitative ring 14; after the water sample enters the detection pool 15, the second electric sampling valve 10 is closed, and the second sampling pump 12 is closed; at this time, the detector 16 outputs the absorbance of the water sample to the display interface in real time online; at the same time, the absorbance test value of the water sample is fed back to the threshold judgment module, and the absorbance of the water sample in the detection pool 15 detected in real time is compared with the preset water sample absorbance threshold value, so as to judge the amount of residual hydrogen peroxide, and send instructions to the dosing system 30 to reduce the amount of dosing.

[0050] The residual hydrogen peroxide monitoring and removal system and method described in the present invention can monitor the content of residual hydrogen peroxide added to the condensate of the direct air-cooled condenser and eliminate the residual hydrogen peroxide by designing a residual removal subsystem and a monitoring subsystem, so as to ensure the long-term operation of the fine treatment mixed bed and protect the normal operation of the high-temperature and high-pressure section valves of the unit's water vapor system, which is of great significance for ensuring the economic and safe operation of the unit.

[0051] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

Claims

1. A residual hydrogen peroxide monitoring and removal system, characterized in that: It comprises a residual removal subsystem and a monitoring subsystem; the residual removal subsystem is used to remove residual hydrogen peroxide in condensate water, and the residual removal subsystem comprises a low-pressure heater (1), a first catalytic reactor (2) and a cooler (3); The cold side inlet of the low-pressure heater (1) is connected to the outlet of the condensate collecting tank (28), the cold side outlet of the low-pressure heater (1) is connected to the inlet of the first catalytic reactor (2), the outlet of the first catalytic reactor (2) is connected to the hot side inlet of the cooler (3), and the hot side outlet of the cooler (3) is used to be connected to the inlet of the fine treatment mixed bed (5); wherein the last stage extraction steam of the low-pressure cylinder of the steam turbine is introduced into the low-pressure heater (1) as a heating source; The monitoring subsystem is used to monitor the residual hydrogen peroxide in the condensate in real time; wherein the monitoring subsystem is provided with two sampling inlets, the first sampling inlet is connected to a first preset sampling point, and the second sampling inlet is connected to a second preset sampling point; the first preset sampling point is located between the condensate collecting tank (28) and the low-pressure heater (1), and the second preset sampling point is located between the cooler (3) and the fine treatment mixed bed (5).

2. A residual hydrogen peroxide monitoring and removal system according to claim 1, characterized in that: The residual removal subsystem further comprises an electric main valve (4), an electric bypass valve (7) and a second catalytic reactor (8); the electric main valve (4) is arranged between the cooler (3) and the polishing mixed bed (5); the electric bypass valve (7) is connected in series with the second catalytic reactor (8) and then connected in parallel with the electric main valve (4) between the cooler (3) and the polishing mixed bed (5).

3. A residual hydrogen peroxide monitoring and removal system according to claim 1, characterized in that: The monitoring subsystem comprises an electromagnetic four-way valve (13), a detection pool (15) and a detector (16); port b of the electromagnetic four-way valve (13) is connected to the first preset sampling point, and port c of the electromagnetic four-way valve (13) is connected to the second preset sampling point; port d of the electromagnetic four-way valve (13) is connected to the water sample inlet of the detection pool (15), and the detector (16) is arranged at a preset position of the detection pool (15); wherein the detector (16) is used to detect the absorbance of the water sample in the detection pool (15) in real time.

4. A residual hydrogen peroxide monitoring and removal system according to claim 3, characterized in that: The monitoring subsystem further comprises a detection reagent storage tank (17), a reagent shut-off valve (18), a reagent feed pump (19) and a reagent quantitative ring (20); The detection reagent storage tank (17) stores detection reagent, the outlet of the detection reagent storage tank (17) is connected to the inlet of the reagent shut-off valve (18), the outlet of the reagent shut-off valve (18) is connected to the inlet of the reagent feed pump (19), the outlet of the reagent feed pump (19) is connected to the inlet of the reagent quantitative ring (20), and the outlet of the reagent quantitative ring (20) is connected to the reagent inlet of the detection cell (16).

5. A residual hydrogen peroxide monitoring and removal system according to claim 3, characterized in that: The monitoring subsystem further comprises a desalted water storage tank (21) and a desalted water flushing pump (23); The desalted water storage tank (21) stores desalted water, the outlet of the desalted water storage tank (21) is connected to the inlet of the desalted water flushing pump (23), and the outlet of the desalted water flushing pump (23) is connected to port a of the electromagnetic four-way valve (14).

6. A residual hydrogen peroxide monitoring and removal system according to claim 3, characterized in that: The monitoring subsystem further comprises a first electric sampling valve (9), a second electric sampling valve (10), a first injection pump (11) and a second injection pump (12); The first electric sampling valve (9) and the first sampling pump (11) are connected in series between the first preset sampling point and the port b of the electromagnetic four-way valve (13); the second electric sampling valve (10) and the second sampling pump (12) are connected in series between the second preset sampling point and the port c of the electromagnetic four-way valve (13).

7. A residual hydrogen peroxide monitoring and removal system according to claim 3, characterized in that: Also includes a control subsystem; the control subsystem includes a display (26) and an automatic controller (27); The display (26) has a human-computer interaction function, and is used to receive system operating parameters sent by a user, and send the system operating parameters to the residual removal subsystem and the monitoring subsystem; and is also used to display the absorbance of the water sample in the detection pool (15) detected in real time; The automatic controller (27) is used to compare the absorbance of the water sample in the detection pool (15) detected in real time with a preset water sample absorbance threshold, and to generate and send system operation instructions to the residual removal subsystem and the monitoring subsystem based on the comparison result; and is also used to generate and send dosing control instructions to the dosing system based on the comparison result.

8. A residual hydrogen peroxide monitoring and removal system according to claim 4, characterized in that: The detection reagent is a mixture of 3-aminophthalhydrazide and sodium hydroxide; the detector (16) is an ultraviolet spectrophotometer.

9. A residual hydrogen peroxide monitoring and removal system according to claim 2, characterized in that: The first catalytic reactor (2) is filled with an iron catalyst, and the second catalytic reactor (8) is filled with a nano manganese dioxide catalyst.

10. A method for monitoring and removing residual hydrogen peroxide, characterized in that: Utilize the residual hydrogen peroxide monitoring and removal system as described in any one of claims 1 to 9; Wherein, the residual hydrogen peroxide monitoring and removal method comprises: The residual hydrogen peroxide in the condensate water is removed by using the residual removal subsystem; The residual hydrogen peroxide in the condensate water is monitored in real time by using the monitoring subsystem; wherein, the operating state of the residual removal subsystem and the dosing system are adjusted according to the real-time monitoring result of the monitoring subsystem.

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