Method and device for on-line continuous monitoring of blast furnace gas condensate water pH value

Abstract

The present application relates to a kind of blast furnace gas condensate pH value on-line continuous monitoring method and device, the device includes condensate collection device, on-line monitoring device and condensate discharge device, by the specific setting of each part of device, cooperate the setting of specific parameter in monitoring method, especially the detailed setting of interlock setting mode and pH monitoring component in it, so that the device and the monitoring method can be quickly and efficiently to the pH value of blast furnace gas Real-time monitoring is carried out, and the safety, timeliness and accuracy of monitoring process are guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of air pollution control, particularly the field of gas control and treatment in the iron and steel metallurgy industry, and specifically relates to a method and device for online continuous monitoring of pH value of blast furnace gas condensate. Background Technology

[0002] During the smelting process in a blast furnace, various raw materials, fluxes, and fuels introduce trace amounts of chlorine into the furnace. The chlorine in the sinter, lump ore, coke, and various additives within the blast furnace exists in forms such as NaCl, KCl, and CaCl2. As materials move downwards within the blast furnace, while the gas rises upwards, chlorine undergoes a series of reactions under the high-temperature reducing atmosphere, ultimately entering the top gas primarily as HCl.

[0003] The existing blast furnace gas pipeline system does not adequately consider the corrosive effects of HCl and other acidic gases on downstream equipment and pipelines, which can lead to significant economic losses and safety hazards for steel plants. Therefore, it is necessary to monitor acidic gases in the blast furnace gas pipeline system, and also monitor the removal efficiency in pipelines equipped with dechlorination devices. Current methods for monitoring blast furnace gas pipelines mainly include online monitoring and condensate sampling. Online monitoring is inaccurate due to the complex composition of blast furnace gas, making it difficult to directly reflect the acidity or alkalinity of the gas. Condensate sampling involves periodically sampling condensate from the blast furnace gas pipeline system and then conducting laboratory analysis. The pH value of the water sample reflects changes in the acidic components of the gas. While this method is accurate, it has a certain lag and cannot provide timely feedback to guide the blast furnace gas deacidification system or make timely adjustments to adapt to changes in operating conditions, thus consuming significant manpower and resources.

[0004] Chinese invention patent publication CN114653181A discloses a method for analyzing trace hydrogen chloride in blast furnace gas. It employs a traditional absorption device to detect the hydrogen chloride content in blast furnace gas. However, this device requires external blast furnace gas intake, preparation of the absorption liquid, and manual analysis, posing certain safety hazards. Furthermore, the test results are not timely and consume considerable manpower and resources. Chinese utility model patent publication CN209927714U discloses a portable gas analyzer based on Fourier transform infrared spectroscopy, also describing a portable gas analyzer. However, due to the complex composition of blast furnace gas, using this analyzer for monitoring leads to inaccurate test results.

[0005] Therefore, for the steel industry, the acidic gases in blast furnace gas, mainly HCl, cause severe corrosion to pipelines and equipment. Existing online detection devices are inaccurate due to the complex composition of blast furnace gas, and traditional absorption detection results cannot reflect the fluctuations in the concentration of acidic gases in the gas in a timely manner, resulting in a certain degree of lag. There is an urgent need to develop a technical solution to solve this problem. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention utilizes the physicochemical properties of acidic gases in blast furnace gas and, based on extensive experimental data, proposes an online continuous monitoring method and device for the pH value of blast furnace gas condensate. This method and device can accurately and promptly reflect the acidity and alkalinity of blast furnace gas, enable steel plants with front-end deacidification equipment to construct an interlocking system to quickly adjust the deacidification effect, and solve the problem of real-time online accurate monitoring of blast furnace gas acidity and alkalinity.

[0007] Specifically, this is achieved through the following technical means:

[0008] An online continuous monitoring device for pH value of blast furnace gas condensate includes a condensate collection device, an online monitoring device, and a condensate discharge device.

[0009] The condensate collection device includes a high-temperature gas discharge component, a condensation component, and a low-temperature gas return component. The high-temperature gas discharge component is used to discharge blast furnace gas from the blast furnace gas discharge pipe into the condensation component. The condensation component is used to cool the discharged blast furnace gas and obtain condensate, and then discharge the obtained condensate. The low-temperature gas return component is used to discharge the cooled low-temperature blast furnace gas back into the blast furnace gas discharge pipe.

[0010] The online monitoring device includes a U-shaped water seal bend and an online pH detection component. The U-shaped water seal bend is used to enrich the condensate discharged from the condensation component in a U-shape to form a dynamic water seal and prevent gas from passing through the online monitoring device. The online pH detection component is installed on the U-shaped water seal bend and is used to perform real-time pH detection on the liquid inside the U-shaped water seal bend.

[0011] The condensate discharge device is used to discharge the liquid discharged from the online monitoring device.

[0012] Preferably, the high-temperature gas discharge component includes a high-temperature gas discharge pipe, a branch inlet ball valve, a gas pressure reducing valve, and an inlet pneumatic ball valve. The inlet of the high-temperature gas discharge pipe is connected to the blast furnace gas discharge pipeline, and the gas pressure in the high-temperature gas discharge pipe is lower than the gas pressure in the blast furnace gas discharge pipeline. The branch inlet ball valve, the gas pressure reducing valve, and the inlet pneumatic ball valve are respectively installed on the high-temperature gas discharge pipe. The gas pressure reducing valve is used to reduce the gas pressure in the high-temperature gas discharge pipe.

[0013] Preferably, the condensing component includes a condenser shell, a cooling water pipe, a condensate collection tank, a cooling water inlet, a cooling water outlet, a high-temperature gas inlet, a low-temperature gas outlet, and a condensate outlet. The cooling water inlet is located at the bottom of the condenser shell, and the cooling water outlet is located at the top of the condenser shell. The cooling water pipe is located inside the condenser shell, and its two ends are connected to the cooling water inlet and the cooling water outlet, respectively. The high-temperature gas inlet is located at the top of the condenser shell or the top of its side wall, and the high-temperature gas inlet is connected to the outlet end of the high-temperature gas discharge pipe. The low-temperature gas outlet is located at the bottom of the condenser shell or the bottom of its side wall. The condensate collection tank is located in the lower part of the condenser shell, and the condensate outlet is located on the side of the condenser shell and is connected to the discharge port of the condensate collection tank.

[0014] Preferably, the cryogenic gas reflux component includes a cryogenic gas discharge pipe, a pressure transmitter, a gas flow meter, an outlet pneumatic ball valve, and a branch outlet ball valve. The inlet end of the cryogenic gas discharge pipe is connected to the cryogenic gas outlet of the condensation component, and the outlet end of the cryogenic gas discharge pipe is connected to the blast furnace gas discharge pipeline. The pressure transmitter, gas flow meter, outlet pneumatic ball valve, and branch outlet ball valve are all installed on the cryogenic gas discharge pipe. The pressure transmitter is interlocked with the inlet pneumatic ball valve and the outlet pneumatic ball valve. When the gas pressure at the outlet end of the cryogenic gas discharge pipe is detected to be lower than the pressure of the blast furnace gas discharge pipeline, or when the gas pressure at the rear end of the gas pressure reducing valve is detected to be higher than the safety pressure threshold of the U-shaped water seal bend, the inlet pneumatic ball valve and the outlet pneumatic ball valve are closed and an alarm is triggered to prevent the gas in the cryogenic gas discharge pipe from flowing backward or the gas pressure fluctuation from breaking the water seal of the U-shaped water seal bend.

[0015] The branch inlet ball valve and the branch outlet ball valve are used to shut down the entire device when the device is not working or when the pneumatic ball valve is not closed tightly.

[0016] Preferably, the low-temperature gas reflux component further includes a venting pipe, which is located between the gas flow meter and the outlet pneumatic ball valve; the venting pipe is used for venting when sampling or when the operation is completed.

[0017] Preferably, the safe pressure threshold of the U-shaped water seal bend is 18-25 kPa (preferably 20 kPa).

[0018] Preferably, the connection point between the inlet of the high-temperature gas discharge pipe and the blast furnace gas discharge pipe is point A, and the connection point between the outlet of the low-temperature gas discharge pipe and the blast furnace gas discharge pipe is point B. A blast furnace gas residual pressure turbine power generation device (i.e., TRT) is installed on the high-temperature gas discharge pipe between points A and B.

[0019] Preferably, the online monitoring device further includes a condensate drain pipe, a condensate flow meter, a condensate drain valve, and a condensate outlet pipe; the inlet end of the condensate drain pipe is connected to the condensate outlet of the condensing component, the outlet end of the condensate drain pipe is connected to the inlet end of the U-shaped water seal bend, the outlet end of the U-shaped water seal bend is connected to the inlet end of the condensate outlet pipe, a condensate flow meter is installed on the condensate drain pipe, and a condensate drain valve is installed at the bottom end of the U-shaped water seal bend.

[0020] The condensate to be tested flows into a U-shaped water seal bend, on which an online pH monitoring device (commercially available equipment) is installed for real-time monitoring. The water seal height of the U-shaped water seal bend is approximately 2.5m.

[0021] Preferably, the condensate drainage device includes an inlet valve, a gas drain, and a condensate drain floor drain; the gas drain includes an inlet pipe, an outlet pipe, and multiple water seal pipes, the inlet pipe is connected to the condensate outlet pipe, the inlet valve is installed on the inlet pipe, the outlet pipe is connected to the condensate drain floor drain via a pipe, and the multiple water seal pipes are sequentially arranged inside the gas drain.

[0022] Preferably, the condenser shell is also provided with a flushing water inlet and a nitrogen purging inlet. The flushing water inlet is used to clean the inside of the condenser shell, and the nitrogen purging inlet is used to purge the condenser shell with nitrogen before operation.

[0023] Preferably, the gas drain of the condensate discharge device is also provided with a water inlet, through which the condensate is discharged to the on-site drainage ditch.

[0024] Preferably, the gas drainer is provided with an insulation layer and a heat tracing device. The insulation layer is disposed on the outer shell of the gas drainer, and the heat tracing device is used to supplement the heat inside the gas drainer.

[0025] A method for online continuous monitoring of pH value in blast furnace gas condensate, using the aforementioned online continuous monitoring device for pH value in blast furnace gas condensate, includes the following steps:

[0026] (1) Nitrogen gas is discharged into the condenser shell through the nitrogen replacement inlet set on the condenser shell to purge the air in the condenser shell. Then, cooling water is continuously discharged into the cooling water pipe through the cooling water inlet and continuously discharged through the cooling water outlet. At the same time, the branch inlet ball valve and the inlet pneumatic ball valve are opened to discharge the blast furnace gas in the blast furnace gas discharge pipe into the high temperature gas discharge pipe. The pressure of the discharged blast furnace gas is set to 15-20 kPa through the gas pressure reducing valve. Then, the pressure-reduced blast furnace gas is discharged into the condenser shell through the high temperature gas inlet through the high temperature gas discharge pipe.

[0027] (2) The high-temperature blast furnace gas discharged into the condenser shell in step (1) is cooled by the cooling water pipe to obtain low-temperature blast furnace gas and condensate. The condensate is collected by the condensate collection tank and discharged through the condensate outlet, and the low-temperature blast furnace gas is discharged through the low-temperature gas outlet.

[0028] (3) The blast furnace gas discharged in step (2) passes through the pressure transmitter, gas flow meter, venting pipe, outlet pneumatic ball valve and branch outlet ball valve in sequence, and is discharged back into the blast furnace gas discharge pipe through the low temperature gas discharge pipe.

[0029] When the gas pressure at the outlet of the low-temperature gas discharge pipe is detected to be lower than the pressure in the blast furnace gas discharge pipe, the inlet pneumatic ball valve and the outlet pneumatic ball valve are closed and an alarm is triggered to prevent the gas in the low-temperature gas discharge pipe from flowing in the opposite direction.

[0030] (4) The condensate discharged in step (2) is drained into the condensate drain pipe. The flow rate of the condensate in the condensate drain pipe is controlled to be 0.5–0.95 m³ / h using a condensate flow meter. 3 / h, control the water seal height of the U-shaped water seal bend to be 2.3 to 5.5m, detect the pH of the condensate in the U-shaped water seal bend through the online pH detection component, and ensure that the U-shaped water seal bend is always in a flowing state with a flow velocity of 0.2 to 0.9m / s. The detected condensate is discharged to the condensate discharge device through the condensate outlet pipe.

[0031] When the gas pressure at the downstream end of the gas pressure reducing valve is detected to be higher than the safety pressure threshold of the U-shaped water seal bend, the inlet pneumatic ball valve and the outlet pneumatic ball valve are closed and an alarm is triggered to prevent gas pressure fluctuations from breaking the water seal of the U-shaped water seal bend.

[0032] Heat exchange through the condenser causes the gas temperature to drop below the dew point, resulting in the production of condensate.

[0033] (5) The condensate discharged in step (4) is discharged into the gas drainer through the condensate outlet pipe, and then discharged through a series of water seals. This further ensures that the blast furnace gas will not break through the water seal and prevents the blast furnace gas from leaking out.

[0034] Preferably, in step (1), the temperature of the high-temperature blast furnace gas discharged into the high-temperature gas discharge pipe is 130–180°C, and the flow rate of the blast furnace gas is 45–55 m³ / h. 3 / h; In step (2), the temperature of the low-temperature blast furnace gas obtained is 15~25℃.

[0035] As a preferred option, the blast furnace gas moisture content is 15 g / m³. 3 about.

[0036] Preferably, the electrode of the online pH detection unit is installed below the U-shaped water seal bend in the water-facing direction. This arrangement provides more accurate detection results, and a sleeve is provided at the electrode mounting location on the U-shaped water seal bend, covering the outside of the electrode. This arrangement facilitates later maintenance.

[0037] Gas drainers are installed to prevent blast furnace gas from leaking out.

[0038] The technical advantages of this invention are as follows:

[0039] (1) This invention utilizes the physicochemical properties of acidic gases in blast furnace gas and, based on extensive experimental data, ultimately obtains an online continuous monitoring device for the pH value of blast furnace gas condensate and a corresponding method. The blast furnace gas is first extracted, then cooled and condensed through a pipe carrying cooling water to obtain condensate. The pH of the continuously flowing condensate is then continuously monitored, and the condensate is specifically controlled and discharged, thereby achieving accurate and timely reflection of the acidity / alkalinity of the blast furnace gas.

[0040] (2) By setting up two pneumatic ball valves for the inlet and outlet pipes, a low-temperature gas return pipe, a gas drainer, and other devices, and by setting up an interlocking system between the pneumatic ball valves and the pressure transmitter, the present invention can prevent the liquid seal from breaking down and the backflow of blast furnace gas on the low-pressure side, thereby fundamentally curbing the safety hazards caused by the leakage of blast furnace gas and ensuring the safety of the overall device.

[0041] Compared to traditional absorption sampling, this invention, by installing an online continuous pH meter, allows for a faster response to the acid-base state of blast furnace gas, reducing the consumption of manpower and reagents. For steel plants with upstream blast furnace gas deacidification systems (such as dechlorination devices), the deacidification system can establish an interlock system with the online continuous pH meter for condensate monitoring set up in this invention. This allows for real-time adjustment of relevant parameters of the deacidification system equipment based on real-time feedback values ​​and trend curves, thereby greatly improving deacidification efficiency and effect.

[0042] The effectiveness of the monitoring device of the present invention was evaluated by arbitrating a device equipped with a dechlorination unit that absorbs HCl in blast furnace gas with alkaline solution. The accuracy of the detection results of two methods, namely online pH monitoring of condensate and online HCl gas analyzer, was compared. Through the derivation and calculation of pH value, the online pH monitoring method is more accurate in detecting HCl in gas and more intuitive in the acid-base balance of gas. This proves that the accuracy of the online continuous monitoring device and monitoring method of the present invention is very high.

[0043] By installing a pressure reducing device (TRT) on the high-temperature gas discharge pipe between point A (where the inlet of the high-temperature gas discharge pipe connects to the blast furnace gas discharge pipe) and point B (where the outlet of the low-temperature gas discharge pipe connects to the blast furnace gas discharge pipe), the gas pressure in the blast furnace gas discharge pipe at point B, after being depressurized by the TRT, is significantly lower than the gas pressure at point A. Therefore, when the blast furnace gas, after being depressurized by the high-temperature gas discharge pipe and monitored by condensation, returns to the blast furnace gas discharge pipe, the pressure at that point is generally higher than the gas pressure in the blast furnace gas discharge pipe at point B without the need for pressurization of the low-temperature gas discharge pipe, thus ensuring normal monitoring of the branch gas flow.

[0044] (3) This invention achieves continuous condensate by rationally setting the pressure of the branch blast furnace gas inlet, the pressure of the outlet, and the flow rate of the gas, and then coordinating the water seal height and water flow velocity of the U-shaped water seal bend. If any parameter (such as the inlet pressure, the gas flow rate, or the water seal height) changes, the amount of condensate will decrease or increase, resulting in condensate flow interruption or a deterioration of the water seal effect of the U-shaped water seal bend. This not only causes discontinuity and inaccuracy in monitoring the pH value of the condensate, but may also lead to blast furnace gas breaking through the water seal and causing a safety accident. Therefore, the parameters set in this invention are closely coordinated with each other, and a change in one affects the whole. The setting of each parameter in this invention can ensure the achievement of the technical effects of this invention. This invention achieves the overall safety and continuity of the device by specifically setting each parameter. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the layout of an online continuous monitoring device for the pH value of blast furnace gas condensate according to one embodiment of the present invention.

[0046] in:

[0047] 000 - Blast furnace gas exhaust pipe;

[0048] 101-Branch inlet ball valve; 102-Gas pressure reducing valve; 103-Inlet pneumatic ball valve; 104-High-temperature gas inlet; 105-Condenser shell; 106-Cooling water pipe; 107-Cooling water outlet; 108-Condensate collection tank; 109-Condensate outlet; 110-Cooling water inlet; 111-Pipeline cooling water makeup inlet; 112-Low-temperature gas outlet; 113-Pressure transmitter; 114-Gas flow meter; 115-Drainage pipe; 116-Outlet pneumatic ball valve; 117-Branch outlet ball valve; 118-Low-temperature gas discharge pipe; 119-High-temperature gas inlet pipe; 120-Drainage circulation components;

[0049] 201-U-shaped water seal bend; 202-Online pH detection component; 203-Condensate flow meter; 204-Condensate drain pipe; 205-Condensate drain valve; 206-Condensate outlet pipe;

[0050] 301-Gas drainer; 302-Water inlet; 303-Water inlet valve; 304-Water inlet valve; 305-Condensate drain; 306-Inlet pipe; 307-Water seal pipe; 308-Outlet pipe. Detailed Implementation

[0051] The process technology solution of the present invention will be further described below with reference to embodiments and accompanying drawings. The orientations mentioned in this specification refer to the orientation of the present invention during normal operation, and do not limit its orientation during storage and transportation; they represent only relative positional relationships, not absolute positional relationships. Unless otherwise specifically described, each feature is merely one example of a series of equivalent or similar features. These embodiments are merely for the purpose of aiding understanding the present invention, and those skilled in the art should understand that they are only for illustrative purposes and should not be considered as specific limitations on the present invention.

[0052] Example 1

[0053] This embodiment illustrates an online continuous monitoring device for the pH value of blast furnace gas condensate installed in the blast furnace workshop of a steel plant. Figure 1 As shown, the monitoring device in this embodiment includes a condensate collection device, an online monitoring device, and a condensate discharge device.

[0054] like Figure 1 As shown, the condensate collection device includes a high-temperature gas discharge component, a condensation component, and a low-temperature gas return component. The high-temperature gas discharge component is used to discharge the blast furnace gas in the blast furnace gas discharge pipe to the condensation component. The condensation component is used to cool the discharged blast furnace gas and obtain condensate, and then discharge the obtained condensate. The low-temperature gas return component is used to discharge the cooled low-temperature blast furnace gas back into the blast furnace gas discharge pipe.

[0055] The online monitoring device includes a U-shaped water seal bend and an online pH detection component. The U-shaped water seal bend is used to enrich the condensate discharged from the condensation component in a U-shape to form a dynamic water seal and prevent gas from passing through the online monitoring device. The online pH detection component is installed on the U-shaped water seal bend and is used to perform real-time pH detection on the liquid inside the U-shaped water seal bend.

[0056] The condensate discharge device is used to discharge the liquid discharged from the online monitoring device.

[0057] More specifically, such as Figure 1As shown, the high-temperature gas discharge component includes a high-temperature gas discharge pipe, a branch inlet ball valve, a gas pressure reducing valve, and an inlet pneumatic ball valve. The inlet of the high-temperature gas discharge pipe is connected to the blast furnace gas discharge pipeline (for example, in this embodiment, it is installed at the bag filter outlet of the blast furnace gas discharge pipeline), and the gas pressure in the high-temperature gas discharge pipe is lower than the gas pressure in the blast furnace gas discharge pipeline. The branch inlet ball valve, the gas pressure reducing valve, and the inlet pneumatic ball valve are respectively installed on the high-temperature gas discharge pipe. The gas pressure reducing valve is used to reduce the gas pressure in the high-temperature gas discharge pipe.

[0058] The condensing component includes a condenser shell, cooling water pipes, a condensate collection tank, a cooling water inlet, a cooling water outlet, a high-temperature gas inlet, a low-temperature gas outlet, and a condensate outlet. The cooling water inlet is located at the bottom of the condenser shell, and the cooling water outlet is located at the top of the condenser shell. The cooling water pipe is located inside the condenser shell, and its two ends are connected to the cooling water inlet and the cooling water outlet, respectively. The high-temperature gas inlet is located at the top of the condenser shell or the top of its side wall, and it is connected to the outlet end of a high-temperature gas discharge pipe. The low-temperature gas outlet is located at the bottom of the condenser shell or the bottom of its side wall. The condensate collection tank is located in the lower part of the condenser shell, and the condensate outlet is located on the side of the condenser shell and is connected to the discharge port of the condensate collection tank.

[0059] The cryogenic gas reflux component includes a cryogenic gas discharge pipe, a pressure transmitter, a gas flow meter, a venting pipe, an outlet pneumatic ball valve, and a branch outlet ball valve. The inlet end of the cryogenic gas discharge pipe is connected to the cryogenic gas outlet of the condensation component, and the outlet end of the cryogenic gas discharge pipe is connected to the blast furnace gas discharge pipe. The pressure transmitter, gas flow meter, venting pipe, outlet pneumatic ball valve, and branch outlet ball valve are all installed on the cryogenic gas discharge pipe. The pressure transmitter is interlocked with the inlet and outlet pneumatic ball valves. When the gas pressure at the outlet end of the cryogenic gas discharge pipe is detected to be lower than the pressure of the blast furnace gas discharge pipe, or when the gas pressure at the rear end of the gas pressure reducing valve is detected to be higher than the safety pressure threshold of the U-shaped water seal bend, the inlet and outlet pneumatic ball valves are closed and an alarm is triggered to prevent reverse flow of gas in the cryogenic gas discharge pipe or gas pressure fluctuations from breaking the water seal of the U-shaped water seal bend.

[0060] In this embodiment, the safe pressure threshold of the U-shaped water seal bend can be set to 20 kPa.

[0061] like Figure 1As shown, a TRT is installed on the high-temperature gas discharge pipe between point A, where the inlet of the high-temperature gas discharge pipe connects to the blast furnace gas discharge pipe, and point B, where the outlet of the low-temperature gas discharge pipe connects to the blast furnace gas discharge pipe. This ensures that even after pressure reduction treatment, the pressure of the blast furnace gas at the outlet of the low-temperature gas discharge pipe is higher than the pressure of the blast furnace gas in the high-temperature gas discharge pipe at point B, thus preventing blast furnace gas backflow.

[0062] like Figure 1 As shown, the online monitoring device also includes a condensate drain pipe, a condensate flow meter, a condensate drain valve, and a condensate outlet pipe; the inlet end of the condensate drain pipe is connected to the condensate outlet of the condensing component, the outlet end of the condensate drain pipe is connected to the inlet end of the U-shaped water seal bend, the outlet end of the U-shaped water seal bend is connected to the inlet end of the condensate outlet pipe, a condensate flow meter is installed on the condensate drain pipe, and a condensate drain valve is installed at the bottom end of the U-shaped water seal bend.

[0063] like Figure 1 As shown, the condensate drainage device includes an inlet valve, a gas drain, and a condensate drain floor drain. The gas drain includes an inlet pipe, an outlet pipe, and multiple water seal pipes. The inlet pipe is connected to the condensate outlet pipe, the inlet valve is installed on the inlet pipe, the outlet pipe is connected to the condensate drain floor drain via a pipe, and the multiple water seal pipes are sequentially arranged inside the gas drain.

[0064] Furthermore, in this embodiment, the condenser shell may also be provided with a flushing water inlet and a nitrogen purging inlet. The flushing water inlet is used to clean the inside of the condenser shell, and the nitrogen purging inlet is used to purge the condenser shell with nitrogen before operation.

[0065] Furthermore, in this embodiment, a water inlet and a water inlet valve are provided on one side of the gas drain of the condensate discharge device, and the condensate is discharged to the on-site drainage ditch through the gas drain.

[0066] To adapt to use in cold regions, the gas drainer in this embodiment is equipped with an insulation layer and a heat tracing device. The insulation layer is disposed on the outer shell of the gas drainer, and the heat tracing device is used to supplement the heat inside the gas drainer.

[0067] In this embodiment, the electrode of the online pH detection component is installed in the water-facing direction below the U-shaped water seal bend, and a sleeve is provided at the electrode installation location on the U-shaped water seal bend, with the sleeve covering the outside of the electrode.

[0068] Example 2

[0069] This embodiment describes a method for online continuous monitoring of pH value in blast furnace gas condensate using the apparatus of Embodiment 1, comprising the following steps:

[0070] (1) The blast furnace gas is drawn out of the main pipeline (blast furnace gas discharge pipeline) after bag filter dust removal using a DN40 pipeline. Before this, nitrogen is first discharged into the condenser shell through the nitrogen replacement inlet set on the condenser shell to purge the air in the condenser shell. Then, cooling water is continuously discharged into the cooling water pipeline through the cooling water inlet and continuously discharged through the cooling water outlet. The cooling water of the water-cooled condenser adopts the "bottom inlet, top outlet" transportation method. At the same time, the branch inlet ball valve and the inlet pneumatic ball valve are opened to discharge the dust-removed blast furnace gas in the blast furnace gas discharge pipeline into the high-temperature gas discharge pipe. The pressure of the discharged blast furnace gas is set to 15-20 kPa through the gas pressure reducing valve, and the gas flow rate is maintained at 50 m³ / h. 3 / h. Then, the depressurized blast furnace gas is discharged into the condenser shell through the high-temperature gas inlet via the high-temperature gas discharge pipe.

[0071] (2) The high-temperature blast furnace gas discharged into the condenser shell in step (1) is cooled by the cooling water pipe to obtain low-temperature blast furnace gas and condensate (the acidic gas and water vapor in the gas are reduced to below the dew point and condensate is generated after passing through the heat exchange pipe of the cooling water). The condensate is collected by the condensate collection tank and discharged through the condensate outlet. The low-temperature blast furnace gas is discharged through the low-temperature gas outlet. The average temperature of the blast furnace gas after heat exchange is 20°C.

[0072] (3) The blast furnace gas discharged in step (2) passes through the pressure transmitter, gas flow meter, venting pipe, outlet pneumatic ball valve and branch outlet ball valve in sequence, and is discharged back into the blast furnace gas discharge pipe through the low temperature gas discharge pipe.

[0073] The pressure transmitter is interlocked with the two pneumatic ball valves (inlet and outlet). When the pressure after the pressure reducing valve is higher than the liquid seal safety pressure by 20 kPa or the low-temperature gas outlet pressure is lower than the pressure of the blast furnace gas main pipeline on the low-pressure side, an alarm will be triggered and the pneumatic ball valve will automatically close to prevent gas pressure fluctuations from breaking down the downstream liquid seal and causing backflow in the low-pressure side gas main pipeline.

[0074] (4) The condensate discharged in step (2) is drained into the condensate drain pipe, and the flow rate of the condensate in the condensate drain pipe is controlled to be 0.75 m³ / s by a condensate flow meter. 3The system controls the water seal height of the U-shaped water seal bend to be 2.5m per hour. The pH of the condensate in the U-shaped water seal bend is detected using the online pH detection component. A drain valve is installed at the bottom of the U-shaped pipe for easy maintenance. The monitoring system's piping (e.g., condensate drain pipe, U-shaped water seal bend, etc.) uses DN25 stainless steel pipes to ensure the condensate is constantly flowing at a velocity of 0.5m / s. The detected condensate is discharged into the condensate discharge device through the condensate outlet pipe. The electrode is installed below the U-shaped bend in the water-facing direction for more accurate results. The electrode is installed after the drain valve using a sleeve for easy maintenance.

[0075] (5) The condensate discharged in step (4) is discharged into the gas drainer through the condensate outlet pipe, and then discharged through the step-by-step water seal.

[0076] This embodiment uses a dechlorination device installed on the blast furnace gas exhaust pipe. The device detects the accuracy and reaction time of the online pH meter during the process of the dechlorination device's injection rate increasing from offline to 50 kg / h and then to 100 kg / h. The results, obtained by taking three monitoring times at different times, are shown in Table 1. Table 1 presents the data related to the accuracy and stabilization time of multiple sets of online pH detection components under different injection intensities in Embodiment 2 of this invention.

[0077] Table 1

[0078]

[0079] Table 1 shows that all three sets of experiments indicate that when the dechlorination device is not operating, the pH value of the blast furnace gas remains in a strongly acidic state (around 2). However, when the dechlorination device's injection rate reaches a moderate intensity of 50 kg / h, the pH value increases significantly, basically maintaining a relatively weakly acidic state between 4 and 5. This demonstrates that the device of the present invention can display the dechlorination effect of the dechlorination device in real time. When the dechlorination device's injection rate reaches an intensity of 100 kg / h, the pH value further increases significantly to a neutral level close to 7, and the pH value curve stabilizes in about 10 minutes. This shows that the device of the present invention can monitor the pH value of the blast furnace gas in real time and quickly.

[0080] Comparative Example 1

[0081] This comparative example does not have branch pipelines; instead, the cooling water pipe, condensate collection tank, and condensate outlet are directly installed inside the blast furnace gas exhaust pipe. Through pH monitoring of the collected condensate, a 10-hour test revealed that this setup not only frequently resulted in condensate flow interruptions but also made it very difficult to determine the pH stabilization time. This is because there is too much gas in the blast furnace gas exhaust pipe that did not participate in condensation, thus having a very unstable impact on the condensation process. This further demonstrates that the overall device specifically designed in this invention has stability and reliability for continuous online monitoring of the condensate pH value.

[0082] Comparative Example 2

[0083] The other settings in this comparative example are the same as in Examples 1 and 2, except that the pressure of the blast furnace gas discharged into the pipe through the gas pressure reducing valve is adjusted to 6-10 kPa, and the flow rate of the blast furnace gas is correspondingly reduced. Except for the parameters naturally affected by pressure, all other parameters are kept the same as in Example 2. During the experiment, it was found that the water seal height in the U-shaped water seal bend slowly decreased until it lost its water seal effect. The experiment ended when the pneumatic valve was closed. This proves that the pressure parameters and water seal height parameters set in this invention are closely coordinated and have a synergistic effect. Changing one or two parameters will cause the other parameters to fail or become unsuitable for this invention, thus resulting in a failure of the effect.

[0084] Comparative Example 3

[0085] The other settings in this comparative example are the same as in Examples 1 and 2, except that the pressure of the blast furnace gas discharged into the pipe through the gas pressure reducing valve is adjusted to 38-45 kPa, and the flow rate of the blast furnace gas also increases accordingly. Except for the parameters naturally affected by pressure, all other settings remain the same as in Example 2. During the experiment, it was found that when the gas pressure was increased, the flow rate increased, but the detected moisture content was not as high as when the pressure was adjusted to 20 kPa (only 10 g / m³). 3 The flow rate is high (around 1000 km / h), while the water content in the gas is stable. This means that at high flow rates, the condensate in the gas does not completely condense, which affects the detection. As the flow rate increases, the condensate velocity increases, leading to unstable electrode detection results. This further proves that the pressure parameters and water seal height parameters set in this invention are closely coordinated and have a synergistic effect.

[0086] The technical principles and examples of the present invention have been described above with reference to specific embodiments. The embodiments and comparative examples described above are merely examples and do not limit the scope of protection of the technical solutions. Technical effects not compared can be clearly described through the textual description of the technical effects, and do not imply a low level of inventiveness. These descriptions are only for explaining the principles and examples of the present invention and should not be construed as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can conceive of other specific embodiments of the present invention without creative effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A method for online continuous monitoring of pH value in blast furnace gas condensate, characterized in that, The equipment used includes a condensate collection device, an online monitoring device, and a condensate discharge device; The condensate collection device includes a high-temperature gas discharge component, a condensation component, and a low-temperature gas return component. The high-temperature gas discharge component is used to discharge the blast furnace gas in the blast furnace gas discharge pipe to the condensation component. The condensation component is used to cool the discharged blast furnace gas and obtain condensate, and then discharge the obtained condensate. The low-temperature gas return component is used to discharge the cooled low-temperature blast furnace gas back to the blast furnace gas discharge pipe. The online monitoring device includes a U-shaped water seal bend and an online pH detection component. The U-shaped water seal bend is used to enrich the condensate discharged from the condensation component in a U-shape to form a dynamic water seal and prevent gas from passing through the online monitoring device. The online pH detection component is installed on the U-shaped water seal bend and is used to perform real-time pH detection on the liquid inside the U-shaped water seal bend. The condensate drain device is used to discharge the liquid discharged from the online monitoring device; Includes the following steps: (1) Nitrogen gas is introduced into the condenser shell through the nitrogen replacement inlet installed on the condenser shell to purge the air inside the condenser shell. Then, cooling water is continuously discharged into the cooling water pipeline through the cooling water inlet and continuously discharged through the cooling water outlet. At the same time, the branch inlet ball valve and the inlet pneumatic ball valve are opened to bring the temperature of the blast furnace gas discharge pipeline to 130~180℃ and the flow rate to 45~55 m³ / h. 3 The blast furnace gas is discharged into the high-temperature gas inlet pipe at a rate of 1 / h, and the pressure of the discharged blast furnace gas is set to 15~20kPa through the gas pressure reducing valve. Then, the pressure-reduced blast furnace gas is discharged into the condenser shell through the high-temperature gas inlet pipe. (2) The high-temperature blast furnace gas discharged into the condenser shell in step (1) is cooled by the cooling water pipe to obtain low-temperature blast furnace gas and condensate at 15~25℃. The condensate is collected by the condensate collection tank and discharged through the condensate outlet. The low-temperature blast furnace gas is discharged through the low-temperature gas outlet. (3) The blast furnace gas discharged in step (2) passes through the pressure transmitter, gas flow meter, venting pipe, outlet pneumatic ball valve and branch outlet ball valve in sequence, and is discharged back into the blast furnace gas discharge pipe through the low temperature gas discharge pipe. When the gas pressure at the outlet end of the low-temperature gas discharge pipe is detected to be lower than the pressure of the blast furnace gas discharge pipe, the inlet pneumatic ball valve and the outlet pneumatic ball valve are closed and an alarm is triggered to prevent the gas in the low-temperature gas discharge pipe from flowing in reverse. (4) The condensate discharged in step (2) is discharged into the condensate drain pipe, and the flow rate of the condensate in the condensate drain pipe is controlled to be 0.5~0.95 m by the condensate flow meter. 3 / h, control the water seal height of the U-shaped water seal bend to be 2.3~5.5m, detect the pH of the condensate in the U-shaped water seal bend through the online pH detection component, and ensure that the U-shaped water seal bend is always in a flowing state with a flow velocity of 0.2~0.9m / s, and discharge the detected condensate to the condensate discharge device through the condensate outlet pipe; When the gas pressure at the downstream end of the gas pressure reducing valve is detected to be higher than the safety pressure threshold of the U-shaped water seal bend, the inlet pneumatic ball valve and the outlet pneumatic ball valve are closed and an alarm is triggered to prevent gas pressure fluctuations from breaking the water seal of the U-shaped water seal bend. (5) The condensate discharged in step (4) is discharged into the gas drainer through the condensate outlet pipe, and then discharged through the step-by-step water seal.

2. The method for online continuous monitoring of pH value of blast furnace gas condensate according to claim 1, characterized in that, The high-temperature gas discharge component includes a high-temperature gas discharge pipe, a branch inlet ball valve, a gas pressure reducing valve, and an inlet pneumatic ball valve. The inlet of the high-temperature gas discharge pipe is connected to the blast furnace gas discharge pipeline, and the gas pressure in the high-temperature gas discharge pipe is lower than the gas pressure in the blast furnace gas discharge pipeline. The branch inlet ball valve, the gas pressure reducing valve, and the inlet pneumatic ball valve are respectively installed on the high-temperature gas discharge pipe. The gas pressure reducing valve is used to reduce the gas pressure in the high-temperature gas discharge pipe. The condensing component includes a condenser shell, cooling water pipes, a condensate collection tank, a cooling water inlet, a cooling water outlet, a high-temperature gas inlet, a low-temperature gas outlet, and a condensate outlet. The cooling water inlet is located at the bottom of the condenser shell, and the cooling water outlet is located at the top of the condenser shell. The cooling water pipes are located inside the condenser shell and are connected to the cooling water inlet and the cooling water outlet at both ends, respectively. The high-temperature gas inlet is located at the top of the condenser shell or the top of the side wall and is connected to the outlet end of the high-temperature gas discharge pipe. The low-temperature gas outlet is located at the bottom of the condenser shell or the bottom of the side wall. The condensate collection tank is located in the lower part of the condenser shell, and the condensate outlet is located on the side of the condenser shell and is connected to the discharge port of the condensate collection tank. The cryogenic gas reflux component includes a cryogenic gas discharge pipe, a pressure transmitter, a gas flow meter, an outlet pneumatic ball valve, and a branch outlet ball valve. The inlet end of the cryogenic gas discharge pipe is connected to the cryogenic gas outlet of the condensation component, and the outlet end of the cryogenic gas discharge pipe is connected to the blast furnace gas discharge pipeline. The pressure transmitter, gas flow meter, outlet pneumatic ball valve, and branch outlet ball valve are all installed on the cryogenic gas discharge pipe. The pressure transmitter is interlocked with the inlet and outlet pneumatic ball valves. When the gas pressure at the outlet end of the cryogenic gas discharge pipe is detected to be lower than the pressure of the blast furnace gas discharge pipeline, or when the gas pressure at the rear end of the gas pressure reducing valve is detected to be higher than the safety pressure threshold of the U-shaped water seal bend, the inlet and outlet pneumatic ball valves are closed and an alarm is triggered to prevent reverse flow of gas in the cryogenic gas discharge pipe or gas pressure fluctuations from breaking the water seal of the U-shaped water seal bend.

3. The method for online continuous monitoring of pH value of blast furnace gas condensate according to claim 2, characterized in that, The safe pressure threshold for a U-shaped water seal bend is 18~25 kPa; The low-temperature gas reflux component also includes a venting pipe, which is located between the gas flow meter and the outlet pneumatic ball valve; Point A is the junction between the inlet of the high-temperature gas discharge pipe and the blast furnace gas discharge pipe, and point B is the junction between the outlet of the low-temperature gas discharge pipe and the blast furnace gas discharge pipe. A blast furnace gas residual pressure turbine power generation device is installed on the high-temperature gas discharge pipe between points A and B.

4. The method for online continuous monitoring of pH value of blast furnace gas condensate according to claim 2 or 3, characterized in that, The online monitoring device also includes a condensate drain pipe, a condensate flow meter, a condensate drain valve, and a condensate outlet pipe; the inlet end of the condensate drain pipe is connected to the condensate outlet of the condensing component, the outlet end of the condensate drain pipe is connected to the inlet end of the U-shaped water seal bend, the outlet end of the U-shaped water seal bend is connected to the inlet end of the condensate outlet pipe, a condensate flow meter is installed on the condensate drain pipe, and a condensate drain valve is installed at the bottom end of the U-shaped water seal bend.

5. The method for online continuous monitoring of pH value of blast furnace gas condensate according to claim 4, characterized in that, The condensate drainage device includes an inlet valve, a gas drain, and a condensate drain floor drain; the gas drain includes an inlet pipe, an outlet pipe, and multiple water seal pipes, the inlet pipe is connected to the condensate outlet pipe, the inlet valve is installed on the inlet pipe, the outlet pipe is connected to the condensate drain floor drain through a pipe, and the multiple water seal pipes are arranged sequentially inside the gas drain.

6. The method for online continuous monitoring of pH value of blast furnace gas condensate according to claim 2 or 5, characterized in that, The condenser shell is also provided with a flushing water inlet and a nitrogen purging inlet. The flushing water inlet is used to clean the inside of the condenser shell, and the nitrogen purging inlet is used to purge the condenser shell with nitrogen before operation.

7. The method for online continuous monitoring of pH value of blast furnace gas condensate according to claim 2 or 5, characterized in that, The gas drain of the condensate discharge device is also equipped with a water inlet. The gas drain is also equipped with an insulation layer and a heat tracing device. The insulation layer is set on the outer shell of the gas drain, and the heat tracing device is used to supplement the heat inside the gas drain.

8. The method for online continuous monitoring of pH value of blast furnace gas condensate according to claim 1, characterized in that, The electrode of the online pH detection component is installed in the water-facing direction below the U-shaped water seal bend, and a sleeve is provided at the electrode installation location in the U-shaped water seal bend, the sleeve being fitted over the outside of the electrode.

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