Sulfur dioxide detection device and detection method for blast furnace gas before and after fine desulfurization

Abstract

This invention relates to a sulfur dioxide detection device and method applicable to blast furnace gas before and after fine desulfurization. The detection device includes a pre-desulfurization gas control component, a post-desulfurization gas control component, a blast furnace gas combustion device, and SO2 and O2 detection devices. The detection method includes steps such as preheating the combustion device, igniting and burning the pre-desulfurization blast furnace gas and air, detecting the pre-desulfurization gas combustion gas, switching to combustion of post-desulfurization gas, detecting the post-desulfurization gas combustion gas, and performing result analysis and comparison. By specifically configuring the device and setting each step, continuous switching combustion is achieved to separately measure the sulfur dioxide content of the combustion gas, thereby enabling real-time monitoring of the desulfurization results of the fine desulfurization device and real-time prediction of different combustion conditions at the user end, greatly improving the monitoring effect of the fine desulfurization device.

Description

Technical Field

[0001] This invention relates to the field of industrial flue gas treatment technology, and in particular to a sulfur dioxide detection device suitable for use before and after fine desulfurization of blast furnace gas. Background Technology

[0002] Blast furnace gas, a high-value byproduct of metallurgical and steel production processes, has a complex and diverse composition. It primarily contains core gases such as carbon monoxide (CO), carbon dioxide (CO2), nitrogen (N2), hydrogen (H2), and methane (CH4), and more importantly, it also contains a certain amount of sulfide impurities. Its sulfur content requires close attention from the perspectives of environmental management and secondary energy utilization. These sulfides encompass two main categories: inorganic sulfur and organic sulfur. Inorganic sulfur is mainly composed of hydrogen sulfide (H2S), while organic sulfur includes carbonyl sulfide (COS), carbon disulfide (CS2), thiols, sulfides, thiophenes, and other components. The total sulfur content of blast furnace gas typically ranges from 60 to 150 mg / Nm³. 3 The sulfur content ranges from approximately 10% to 80%, with carbonyl sulfur (COS) being the most abundant organic sulfur component, along with other organic sulfur components. Inorganic sulfur (H2S) accounts for 20% to 40%, and this sulfur content presents unique challenges for subsequent desulfurization treatment and detection.

[0003] With the increasing emphasis placed on ecological and environmental protection by the state, environmental governance standards in the steel industry are becoming increasingly stringent, and a series of targeted policy documents have been issued, clearly defining the direction for blast furnace gas desulfurization. Documents such as the "Opinions on Promoting Ultra-Low Emissions in the Steel Industry" (Huan Daqi

[2019] No. 35), the "Notice on Doing a Good Job in the Assessment and Testing of Ultra-Low Emissions in Steel Enterprises" (Huan Ban Daqi Han

[2019] No. 922), and the "Technical Guidelines for Ultra-Low Emission Transformation of Steel Enterprises" all explicitly encourage steel enterprises to strengthen pollution source control and stipulate the mandatory requirement that "blast furnace gas should implement fine desulfurization." Fine desulfurization technology for blast furnace gas can significantly reduce sulfur content at the source, effectively reducing pollutant emissions and saving the high investment and long-term operation and maintenance costs of end-of-pipe desulfurization facilities, thus achieving both environmental and economic benefits. Sulfur content is crucial for comprehensive detection. However, due to the complex sulfur composition of blast furnace gas (coexistence of inorganic and organic sulfur), existing online continuous detection equipment on the market cannot meet the functional requirements of accurate and comprehensive detection, which has become a key bottleneck restricting the efficient implementation of fine desulfurization technology.

[0004] Chinese patent application CN110849984A discloses a method for detecting sulfides in industrial coal gas. The core principle involves passing a coal gas sample through a gas chromatographic column under specific conditions to separate hydrogen sulfide from other components in the gas, and then using a gas chromatographic detector to determine the sulfide composition and content. However, this method has significant drawbacks in practical applications and is difficult to adapt to the real-time control requirements of blast furnace gas desulfurization processes. Firstly, this method relies on a chromatographic analyzer and typically employs offline sampling and testing. Factors such as operating standards, sampling location, and sample storage conditions during sampling can significantly affect the test results. Different sampling specifications can easily lead to data deviations, failing to accurately reflect the real-time actual content of sulfides in the coal gas. Secondly, the analysis cycle is relatively long, requiring time from sample collection and pretreatment to detection and result output, making continuous real-time analysis of sulfide content impossible, and the test results exhibit a significant lag. This lag makes it difficult for enterprises to respond quickly to changes in gas composition, adjust desulfurization process parameters in a timely manner, and ensure the stability of desulfurization effect. It is especially unsuitable for closed-loop control scenarios of desulfurization with high real-time requirements.

[0005] Currently, steel companies primarily employ two technical approaches for sulfide detection in blast furnace gas desulfurization processes, but both have significant limitations and cannot meet the requirements for process optimization and environmental compliance. The first approach involves installing online hydrogen sulfide detection equipment at the desulfurization outlet to assess desulfurization effectiveness by monitoring the hydrogen sulfide content in real time. However, practical application shows that this type of equipment can only specifically detect inorganic sulfur (H2S) and cannot identify organic sulfur components. Since organic sulfur accounts for 60%–80% of the total sulfur in blast furnace gas, detecting only hydrogen sulfide cannot comprehensively reflect the total sulfur content and desulfurization effect. Furthermore, the complex components in blast furnace gas, such as CO, CO2, and H2, easily interfere with the sensors of the detection equipment, leading to large fluctuations in the detection results and poor data stability. This makes it impossible to provide reliable guidance for adjusting the desulfurization process, and this detection method is gradually being phased out by the industry. The second approach involves adding a gas chromatography-tandem sulfur (GC-S) detector at the desulfurization outlet. Its detection principle is similar to the technical solution in CN110849984A, both employing an extraction sampling mode to send the desulfurized gas into the GC-S for analysis. However, existing GC-S detectors have significant limitations. They can only detect hydrogen sulfide (H2S) and carbonyl sulfide (COS), failing to identify other organic sulfur components such as thiols, thioethers, and thiophenes, thus failing to comprehensively cover all types of sulfides in blast furnace gas. Furthermore, the detection response time is long, typically exceeding 3 minutes, making real-time data feedback impossible. More importantly, the core objective of blast furnace gas desulfurization is to ensure that sulfur dioxide (SO2) emissions from end-user combustion meet standards. However, GC-S analysis can only detect the content of hydrogen sulfide and carbonyl sulfide at the outlet, unable to directly calculate or display the actual SO2 emission concentration at the end, failing to accurately align with environmental compliance requirements. This results in a disconnect between detection data and process objectives, hindering effective process guidance and highlighting significant limitations.

[0006] To address the shortcomings of existing detection technologies and the actual needs of blast furnace gas desulfurization processes, and to achieve closed-loop management of the desulfurization process and enhance the guiding value of detection data for end-of-pipe emission control, it is urgent to develop a new detection device and method that can overcome the functional limitations of existing equipment and achieve continuous, real-time, and direct measurement of sulfur dioxide emission concentrations at both the front and end of blast furnace gas desulfurization. This would accurately capture dynamic changes in sulfur content, providing a reliable basis for real-time adjustment of desulfurization process parameters, thereby ensuring stable and compliant desulfurization results and promoting ultra-low emission targets for steel enterprises. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and develop a device and method for continuous real-time detection of sulfur content in blast furnace gas after fine desulfurization, based on end-user sulfur dioxide indicators. This process not only solves the current problem of the inability to directly detect sulfur dioxide at the outlet of blast furnace gas after fine desulfurization in real time, but also allows for the simulation of sulfur dioxide emission concentrations under different oxygen contents by adjusting the air intake of the device.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for detecting sulfur dioxide before and after fine desulfurization of blast furnace gas, comprising the following steps: (1) Preheat the blast furnace gas combustion device to raise the temperature inside the blast furnace gas combustion device to a preheating temperature of 55~70℃.

[0009] (2) Empty the gas pipeline before fine desulfurization, empty the gas pipeline after fine desulfurization, close the channel between the gas pipeline after fine desulfurization and the blast furnace gas combustion device, and open the channel of the gas pipeline before fine desulfurization to discharge the blast furnace gas before fine desulfurization into the blast furnace gas combustion device, and at the same time discharge air into the blast furnace gas combustion device.

[0010] (3) Ignite and burn the mixed gas in the blast furnace gas combustion device to produce pre-desulfurization combustion gas.

[0011] (4) Start the SO2 and O2 detection device. After the combustion gas generated after step (3) is stably discharged, discharge the combustion gas into the SO2 and O2 detection device to detect the content of SO2 and O2 in the combustion gas.

[0012] (5) After obtaining the detection results of SO2 and O2 content of combustion gas before desulfurization in step (4), the channel between the gas pipeline before fine desulfurization and the blast furnace gas combustion device is closed, while the channel between the gas pipeline after fine desulfurization and the blast furnace gas combustion device is opened to discharge the blast furnace gas after fine desulfurization into the blast furnace gas combustion device, and at the same time, air is continuously discharged into the blast furnace gas combustion device.

[0013] (6) The desulfurized blast furnace gas is burned to obtain desulfurized combustion gas, which is then discharged into the air; (7) After the venting in step (6) continues for 10~15s, the venting is turned off and the desulfurized combustion gas is discharged into the SO2 and O2 detection device to detect the SO2 and O2 content in the desulfurized combustion gas and obtain the detection results of SO2 and O2 content in the desulfurized combustion gas.

[0014] (8) Analyze the test results. When the SO2 content in the desulfurized combustion gas is less than the SO2 content in the combustion gas before desulfurization, and the SO2 content in the desulfurized combustion gas is 80~150 mg / Nm³, 3If the result is positive, it indicates that the blast furnace gas desulfurization is effective; otherwise, the blast furnace gas desulfurization is considered ineffective, and the blast furnace gas desulfurization device should be inspected.

[0015] Preferably, in step (2), the pressure of the blast furnace gas and air before fine desulfurization discharged into the blast furnace gas combustion device is maintained at 0.95~3.2kPa.

[0016] Preferably, the stable discharge of the pre-desulfurization combustion gas generated after combustion in step (3) in step (4) is specifically achieved by continuously discharging for 10-15 seconds before stable discharge.

[0017] Preferably, in step (5), the continuous discharge of air into the blast furnace gas combustion device is achieved by adjusting the air flow rate to 0.5~1L / min and controlling the overall gas flow rate to ensure that the oxygen content after combustion is 5%-18%.

[0018] A sulfur dioxide detection device suitable for blast furnace gas before and after fine desulfurization, the detection device being an apparatus for implementing the above method, comprising a gas control component before desulfurization, a gas control component after desulfurization, a blast furnace gas combustion device, and an SO2 and O2 detection device.

[0019] The pre-desulfurization gas control components include a pre-desulfurization gas pipeline, a pre-desulfurization transmission pipeline, a pre-desulfurization primary ball valve, a pre-desulfurization vent valve, and a pre-desulfurization secondary ball valve. The pre-desulfurization gas pipeline is the section of the blast furnace gas main pipeline before the fine desulfurization operation. An opening is provided on the side of the pre-desulfurization gas pipeline to connect with the inlet end of the pre-desulfurization transmission pipeline. The pre-desulfurization primary ball valve, the pre-desulfurization vent valve, and the pre-desulfurization secondary ball valve are sequentially installed on the pre-desulfurization transmission pipeline.

[0020] The desulfurized gas control components include a desulfurized gas pipeline, a desulfurized transmission pipeline, a primary desulfurized ball valve, a desulfurized vent valve, and a secondary desulfurized ball valve. The desulfurized gas pipeline is the section of the blast furnace gas main pipeline after the fine desulfurization operation. An opening is provided on the side of the desulfurized gas pipeline to connect with the inlet end of the desulfurized transmission pipeline. The primary desulfurized ball valve, the desulfurized vent valve, and the secondary desulfurized ball valve are sequentially installed on the desulfurized transmission pipeline.

[0021] The blast furnace gas combustion device includes a combustion chamber, a three-way valve, a gas dehydration and dust removal device (preferably, for example, a dust removal device containing alumina desiccant in a fixed bed), a gas pressure reducing device, a gas flow meter, an air fan, an air dehydration and dust removal device (preferably, for example, a dust removal device containing alumina desiccant in a fixed bed), an air pressure reducing device, an air flow meter, a combustion gas vent valve, a detection and connection valve, and a bypass valve.

[0022] The SO2 and O2 detection device is used to detect the SO2 and O2 content of the combustion gas discharged from the combustion chamber.

[0023] Preferably, the three-way valve includes a pre-desulfurization gas inlet pipe, a post-desulfurization gas inlet pipe, and a three-way outlet pipe. The outlet end of the pre-desulfurization transmission pipe is connected to the pre-desulfurization gas inlet pipe, the outlet end of the post-desulfurization transmission pipe is connected to the post-desulfurization gas inlet pipe, and the three-way outlet pipe is connected to the inlet of the gas dehydration and dust removal device.

[0024] Preferably, the gas dehydration and dust removal device, the gas pressure reducing device, and the gas flow meter are connected in sequence through pipelines; the air fan introduces external air through pipelines and then discharges it into the air dehydration and dust removal device; the air dehydration and dust removal device, the air pressure reducing device, and the air flow meter are connected in sequence through pipelines.

[0025] Preferably, the combustion chamber includes a preheating device, a gas inlet, an air inlet, and a combustion gas exhaust pipe; the preheating device is a device that heats the gas in the combustion chamber through a resistance wire; the gas inlet is connected to a gas flow meter through a pipe, the air inlet is connected to an air flow meter through a pipe, the combustion gas exhaust pipe includes a main exhaust pipe and a combustion gas vent pipe, a combustion gas vent pipe is provided on the side of the main exhaust pipe, a combustion gas vent valve is provided on the combustion gas vent pipe, and a connecting valve and a bypass valve are provided on the main exhaust pipe (the bypass valve is used to introduce standard gases of sulfur dioxide and oxygen to calibrate the detection device when the combustion system is offline).

[0026] Preferably, the SO2 and O2 detection device is an extraction-type detection device (preferably, for example, a pump-suction electrochemical detector, an ultraviolet absorption method (NDIR / UV) detection system, a pump-suction electrochemical oxygen detector, a paramagnetic oxygen analyzer, a zirconia oxygen analyzer, etc.).

[0027] Preferably, the SO2 and O2 detection device also includes an evacuation pipe.

[0028] As a preferred embodiment, the specific steps for performing the above-mentioned sulfur dioxide detection method using the aforementioned sulfur dioxide detection device are as follows: (1) Turn on the main power supply, air inlet and combustion gas exhaust valve of the blast furnace gas combustion device, turn on the preheating switch to start the preheating device, and complete the preheating when the preheating temperature rises to 55~70℃.

[0029] (2) After preheating, close the pre-desulfurization vent valve, the post-desulfurization primary ball valve and the post-desulfurization secondary ball valve in sequence, and close the connecting valve; open the post-desulfurization vent valve, open the pre-desulfurization primary ball valve and the pre-desulfurization secondary ball valve; and turn on the air blower to discharge air into the blast furnace gas combustion device.

[0030] (3) Adjust the gas pressure reducing device and the air pressure reducing device, open the ignition device of the combustion chamber, adjust the gas flow valve set in the gas flow meter and the air flow valve set in the air flow meter to complete the normal ignition of the blast furnace gas and generate the combustion gas before desulfurization.

[0031] (4) Turn on the main power supply and bypass valve of the SO2 and O2 detection device, start the SO2 and O2 detection device, and after the combustion gas generated before desulfurization in step (3) is stably discharged, open the connecting valve, close the bypass valve, close the combustion gas vent valve, and start detecting the sulfur dioxide concentration after combustion of the blast furnace gas before fine desulfurization.

[0032] (5) After obtaining the detection results of SO2 and O2 content of combustion gas before desulfurization in step (4), the desulfurization exhaust valve is closed in sequence, the desulfurization primary ball valve and the desulfurization secondary ball valve are opened, the desulfurization primary ball valve and the desulfurization secondary ball valve are closed, the desulfurization exhaust valve is opened, and air is continuously discharged into the blast furnace gas combustion device.

[0033] (6) The desulfurized blast furnace gas is burned to obtain desulfurized combustion gas, which is then discharged into the air.

[0034] (7) After the venting in step (6) continues for 10-15 seconds, the venting is turned off and the desulfurized combustion gas is discharged into the SO2 and O2 detection device to detect the SO2 and O2 content in the desulfurized combustion gas and obtain the detection results of SO2 and O2 content in the desulfurized combustion gas (the detection of oxygen content here is mainly because the emission concentration of sulfur dioxide is directly related to the oxygen content. The higher the oxygen concentration, the lower the relative concentration of sulfur dioxide. The national standard requires that flue gas emissions be based on a certain oxygen content. Therefore, it is necessary to control the oxygen content in the flue gas after combustion by adjusting the amount of air entering, so as to achieve the emission meeting the requirements of low sulfur dioxide).

[0035] (8) Analyze the test results. For example, if the SO2 content in the desulfurized combustion gas is less than the SO2 content in the combustion gas before desulfurization, and the SO2 content in the desulfurized combustion gas is 80~150 mg / Nm³, then... 3 If the O2 content is 5%~8%, it proves that the blast furnace gas desulfurization is effective; otherwise, the blast furnace gas desulfurization is considered to be ineffective, and the blast furnace gas desulfurization device should be inspected.

[0036] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects: (1) Since the user ultimately judges the fine desulfurization effect by the sulfur dioxide content after combustion, the present invention sets up a method to first extract blast furnace gas that has not undergone fine desulfurization from the main blast furnace gas pipeline before the fine desulfurization device, mix it with air and then burn it, and then detect the sulfur dioxide and oxygen concentrations in the combustion gas. Then, by switching valves, fine desulfurized blast furnace gas is extracted from the main blast furnace gas pipeline after the fine desulfurization device, and then burned and the sulfur dioxide and oxygen concentrations in the combustion gas are detected. This provides a comparison of the sulfur dioxide concentration in the blast furnace gas combustion gas before and after fine desulfurization, thereby enabling the evaluation of the desulfurization effect of the fine desulfurization process (or device). When a poor desulfurization effect is detected in real time, the fine desulfurization device or process can be corrected or improved in real time, thereby achieving the technical effect of real-time monitoring of the fine desulfurization effect.

[0037] (2) This invention is based on the simulation and measurement of the final flue gas emission of blast furnace gas with different sulfur dioxide contents at the user end after fine desulfurization and combustion, according to the actual situation. That is, the desulfurized blast furnace gas discharged from the main pipeline after fine desulfurization may be combusted by different users under different actual conditions. This invention sets up a separate air inlet channel and various devices, and sets the flow rate of the inlet air in real time. It can predict the sulfur dioxide emission concentration of the final flue gas at the user end under different oxygen contents by sampling the sample gas extracted from the main pipeline of blast furnace gas (it can adjust the oxygen content of the final combustion gas to meet the actual situation of different blast furnace gas of specific users by controlling the air flow rate). Thus, it realizes the pre-simulation monitoring of different usage conditions at the user end at the blast furnace gas end.

[0038] (3) This invention measures the sulfur dioxide content of the combustion gas by continuously switching the combustion of blast furnace gas before and after fine desulfurization, thereby realizing online continuous monitoring. It can continuously detect the concentration of sulfur dioxide in the flue gas discharged after the gas from the fine desulfurization outlet of blast furnace gas is used by end users by adjusting the oxygen input during combustion. It solves the lag of the current gas phase sulfur chromatography detection method for fine desulfurization of blast furnace gas and the limitation of sulfide detection, and realizes the accurate evaluation of the fine desulfurization efficiency of blast furnace gas, providing a more reliable and effective post-evaluation method for fine desulfurization of blast furnace gas. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the connection of the sulfur dioxide detection device applicable to the present invention before and after fine desulfurization of blast furnace gas.

[0040] In the diagram: 101 - Gas pipeline before desulfurization; 102 - Transmission pipeline before desulfurization; 103 - Primary ball valve before desulfurization; 104 - Vent valve before desulfurization; 105 - Secondary ball valve before desulfurization; 201 - Gas pipeline after desulfurization; 202 - Transmission pipeline after desulfurization; 203 - Primary ball valve after desulfurization; 204 - Vent valve after desulfurization; 205 - Secondary ball valve after desulfurization; 301-Combustion chamber; 302-Three-way valve; 303-Gas dehydration and dust removal device; 304-Gas pressure reducing device; 305-Gas flow meter; 306-Air fan; 307-Air dehydration and dust removal device; 308-Air pressure reducing device; 309-Air flow meter; 310-Exhaust main pipe; 311-Combustion gas vent valve; 312-Detection and connection valve; 313-Combustion gas vent pipe; 401 - SO2 and O2 detection device; 402 - Drain pipe; 403 - Bypass valve; A - Air. Detailed Implementation

[0041] To better illustrate the objectives, technical solutions, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. The specific implementation methods, structures, features, and effects of the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art should understand that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0042] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0043] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0044] Example 1 This embodiment is used to illustrate the adoption of... Figure 1 The apparatus shown illustrates a method for detecting sulfur dioxide before and after fine desulfurization of blast furnace gas. This embodiment employs a high-temperature hydrolysis before TRT followed by wet oxidation after TRT for fine desulfurization, specifically including the following steps: 1. Turn on the main power supply, air switch and vent valve of the blast furnace gas combustion system. After the combustion system automatically enters the operation program, turn on the preheating switch. The system will start preheating. When the preheating temperature rises to 60℃, the preheating is complete.

[0045] 2. After preheating, close the gas-side vent valve before fine desulfurization of blast furnace gas in sequence, close the primary ball valve and secondary ball valve on the low-pressure side of blast furnace gas, close the connecting valve between the blast furnace gas combustion system and the SO2 and O2 detection devices, open the gas-side vent valve after fine desulfurization, and open the primary ball valve and secondary ball valve on the gas-side before fine desulfurization.

[0046] 3. Adjust the gas and air pressure reducing devices of the blast furnace gas combustion system to maintain the pressure between 0.95 and 3.2 kPa. Turn on the ignition device of the blast furnace gas burner and adjust the gas flow valve and air flow valve inside the burner to complete the normal ignition of the blast furnace gas.

[0047] 4. Turn on the main power supply and inlet bypass valve of the SO2 and O2 detection device, start the SO2 and O2 detection device, the system enters self-test, and after the self-test is completed, it begins to enter the detection state.

[0048] 5. After the SO2 and O2 detection devices are running stably, open the connecting valve, close the bypass valve, and close the blast furnace gas burner vent valve. Begin detecting the sulfur dioxide concentration of the blast furnace gas after combustion before fine desulfurization. In this embodiment, the flow rate of the blast furnace gas before desulfurization is 1 L / min. Through detection, the SO2 content in the combustion gas obtained after combustion of the blast furnace gas before fine desulfurization in this embodiment is 80-150 mg / Nm³. 3 The O2 content is 5%-8%.

[0049] 6. Sequentially close the vent valve on the gas side after blast furnace gas desulfurization, open the primary and secondary ball valves on the gas side after blast furnace gas desulfurization, close the primary and secondary ball valves on the gas side before blast furnace gas desulfurization, and open the vent valve on the gas side before blast furnace gas desulfurization. At this time, start monitoring the sulfur dioxide emission concentration after combustion of the blast furnace gas after desulfurization.

[0050] In this embodiment, the flow rate of the blast furnace gas after fine desulfurization is 1 L / min. Detection revealed that the SO2 content in the combustion gas obtained after combustion of the finely desulfurized blast furnace gas in this embodiment is 10-30 mg / Nm³. 3 The O2 content is 5%-8%. Therefore, it can be directly obtained through this device. In the implementation of this embodiment, the desulfurization effect of this fine desulfurization device is very effective, without the need for chromatographic sampling analysis.

[0051] Example 2 This embodiment illustrates how different sulfur dioxide concentrations in the final combustion gas are obtained with different air flow rates. Other settings in this embodiment are the same as in Embodiment 1. The difference lies in the fact that during the operation of the device, during the combustion of the blast furnace gas after fine desulfurization, the concentration of O2 in the flue gas after combustion is controlled by adjusting the opening of the air flow valve inside the blast furnace gas burner, thereby simulating the final flue gas sulfur dioxide emission concentration under different oxygen contents. Specifically, by adjusting the opening of the air flow valve inside the blast furnace gas burner to set the air flow rate into the combustion chamber to 1 L / min, the sulfur dioxide and oxygen concentrations in the flue gas are approximately 0-5 mg / Nm³ and 16-18%, respectively. After 10 minutes, the opening of the air flow valve is changed to set the air flow rate into the combustion chamber to 0.5 L / min, resulting in sulfur dioxide and oxygen concentrations in the flue gas of approximately 20-30 mg / Nm³. 3 And approximately 6% (that is, for the actual situation of the blast furnace gas in Embodiment 1 of the present invention, an air flow rate of 0.5 L / min is sufficient to ensure that the concentration of sulfur dioxide is between 10 and 30 mg / Nm³). 3 (Within this requirement). These values ​​are consistent with those measured at the user end after the gas is discharged from the main blast furnace gas pipeline (the two values ​​at the user end are 25 mg / Nm³). 3 (and 5%), thus proving that the simulation of the present invention is real and feasible.

[0052] Comparative Example 1 This comparative example illustrates a comparative test without a blast furnace gas combustion device. The other settings in this comparative example are the same as in Example 1, except that no blast furnace gas combustion device is used. Instead, the blast furnace gas before and after fine desulfurization is tested continuously and intermittently. The results only show the COS and H2S content in the gas, and the sulfur dioxide content cannot be detected. Furthermore, the results calculated solely based on the COS and H2S content in the gas are smaller than the actual end-point detection values ​​(i.e., without combustion, other trace sulfur in the gas cannot be detected by chromatography, leading to lower detection results and distorted detection).

[0053] Comparative Example 2 This comparative example illustrates a method that does not employ switching combustion. Instead, it uses one blast furnace gas combustion device and SO2 and O2 detection devices to continuously monitor the blast furnace gas before fine desulfurization in real time; and another blast furnace gas combustion device and SO2 and O2 detection devices to continuously monitor the blast furnace gas after fine desulfurization in real time. Other setups are the same as in Example 1. Simulation experiments revealed that, under the same blast furnace gas and the same fine desulfurization device, the sulfur dioxide and oxygen concentrations obtained from both devices were essentially consistent with those obtained in Example 1 (specifically, the sulfur dioxide concentration before and after combustion was both in the range of 80~150 mg / Nm³).3 Within the range of approximately 5-8%, the oxygen concentration is between 5% and 8%; after desulfurization, the sulfur dioxide concentration after combustion is between 10-30 mg / Nm³. 3 Within the range of oxygen concentration (5-8%), the results of the two settings are basically the same. However, the setting in this comparative example significantly increases the cost and the factory area. This demonstrates that the continuous switching combustion method with specific settings in Embodiment 1 of the present invention can achieve the same conclusion as the two sets of devices. This not only saves costs and factory area, but also ensures that the data generation location is consistent.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for detecting sulfur dioxide before and after fine desulfurization of blast furnace gas, characterized in that, Includes the following steps: (1) Preheat the temperature inside the blast furnace gas combustion device to a preheating temperature of 55~70℃; (2) Empty the gas pipeline before fine desulfurization and the gas pipeline after fine desulfurization, close the channel between the gas pipeline after fine desulfurization and the blast furnace gas combustion device, open the channel of the gas pipeline before fine desulfurization to discharge the blast furnace gas before fine desulfurization into the blast furnace gas combustion device, and at the same time discharge air into the blast furnace gas combustion device. (3) Ignite and burn the mixed gas in the blast furnace gas combustion device to produce pre-desulfurization combustion gas; (4) Start the SO2 and O2 detection device. After the combustion gas generated after combustion in step (3) is stably discharged, discharge the combustion gas into the SO2 and O2 detection device to detect the content of SO2 and O2 in the combustion gas. (5) After obtaining the detection results of SO2 and O2 content of combustion gas before desulfurization in step (4), the channel between the gas pipeline before fine desulfurization and the blast furnace gas combustion device is closed, and the channel between the gas pipeline after fine desulfurization and the blast furnace gas combustion device is opened to discharge the blast furnace gas after fine desulfurization into the blast furnace gas combustion device, while continuously discharging air into the blast furnace gas combustion device. (6) Combust the desulfurized blast furnace gas to obtain desulfurized combustion gas and then exhaust it into the air; (7) After the venting in step (6) continues for 10~15s, the venting is turned off and the desulfurized combustion gas is discharged into the SO2 and O2 detection device to detect the SO2 and O2 content in the desulfurized combustion gas and obtain the detection results of SO2 and O2 content in the desulfurized combustion gas. (8) Analyze the test results. When the SO2 content in the desulfurized combustion gas is less than the SO2 content in the combustion gas before desulfurization, and the SO2 content in the desulfurized combustion gas is 80~150 mg / Nm³, 3 If the result is positive, it indicates that the desulfurization process is effective; otherwise, the desulfurization process is considered ineffective, and the desulfurization unit should be inspected.

2. The method for detecting sulfur dioxide before and after fine desulfurization of blast furnace gas according to claim 1, characterized in that, In step (2), the pressure of the blast furnace gas and air before fine desulfurization discharged into the blast furnace gas combustion device is maintained at 0.95~3.2kPa.

3. The method for detecting sulfur dioxide before and after fine desulfurization of blast furnace gas according to claim 1 or 2, characterized in that, The stable discharge of the pre-desulfurization combustion gas generated after combustion in step (3) in step (4) specifically means that it is continuously discharged for 10-15 seconds before being stably discharged.

4. The method for detecting sulfur dioxide before and after fine desulfurization of blast furnace gas according to claim 1 or 2, characterized in that, In step (5), the continuous discharge of air into the blast furnace gas combustion device is to adjust the air flow rate to 0.5~1L / min and control the overall gas flow rate so that the oxygen content after combustion is 5%~18%.

5. A sulfur dioxide detection device suitable for use before and after fine desulfurization of blast furnace gas, characterized in that, The detection device is an apparatus for implementing the method according to any one of claims 1 to 4, including a pre-desulfurization gas control component, a post-desulfurization gas control component, a blast furnace gas combustion device, and an SO2 and O2 detection device; The pre-desulfurization gas control components include a pre-desulfurization gas pipeline, a pre-desulfurization transmission pipeline, a pre-desulfurization primary ball valve, a pre-desulfurization vent valve, and a pre-desulfurization secondary ball valve. The pre-desulfurization gas pipeline is the section of the blast furnace gas main pipeline before the fine desulfurization operation. An opening is provided on the side of the pre-desulfurization gas pipeline to connect with the inlet end of the pre-desulfurization transmission pipeline. The pre-desulfurization primary ball valve, the pre-desulfurization vent valve, and the pre-desulfurization secondary ball valve are sequentially installed on the pre-desulfurization transmission pipeline. The desulfurized gas control components include a desulfurized gas pipeline, a desulfurized transmission pipeline, a primary desulfurized ball valve, a desulfurized vent valve, and a secondary desulfurized ball valve. The desulfurized gas pipeline is the section of the blast furnace gas main pipeline after the fine desulfurization operation. An opening is provided on the side of the desulfurized gas pipeline to connect with the inlet end of the desulfurized transmission pipeline. The primary desulfurized ball valve, the desulfurized vent valve, and the secondary desulfurized ball valve are sequentially installed on the desulfurized transmission pipeline. The blast furnace gas combustion device includes a combustion chamber, a three-way valve, a gas dehydration and dust removal device, a gas pressure reducing device, a gas flow meter, an air fan, an air dehydration and dust removal device, an air pressure reducing device, an air flow meter, a combustion gas exhaust valve, a detection and connection valve, and a bypass valve. The SO2 and O2 detection device is used to detect the SO2 and O2 content of the combustion gas discharged from the combustion chamber.

6. The sulfur dioxide detection device for blast furnace gas before and after fine desulfurization according to claim 5, characterized in that, The three-way valve includes a pre-desulfurization gas inlet pipe, a post-desulfurization gas inlet pipe, and a three-way outlet pipe. The outlet end of the pre-desulfurization transmission pipe is connected to the pre-desulfurization gas inlet pipe, the outlet end of the post-desulfurization transmission pipe is connected to the post-desulfurization gas inlet pipe, and the three-way outlet pipe is connected to the inlet of the gas dehydration and dust removal device.

7. The sulfur dioxide detection device for blast furnace gas before and after fine desulfurization according to claim 5 or 6, characterized in that, The gas dehydration and dust removal device, the gas pressure reducing device, and the gas flow meter are connected in sequence through pipelines; the air fan introduces external air through pipelines and then discharges it into the air dehydration and dust removal device; the air dehydration and dust removal device, the air pressure reducing device, and the air flow meter are connected in sequence through pipelines.

8. The sulfur dioxide detection device for blast furnace gas before and after fine desulfurization according to claim 7, characterized in that, The combustion chamber includes a preheating device, a gas inlet, an air inlet, and a combustion gas discharge pipe. The preheating device is a device that heats the gas in the combustion chamber through a resistance wire. The gas inlet is connected to a gas flow meter through a pipe, and the air inlet is connected to an air flow meter through a pipe. The combustion gas discharge pipe includes a main discharge pipe and a combustion gas vent pipe. A combustion gas vent pipe is installed on the side of the main discharge pipe, and a combustion gas vent valve is installed on the combustion gas vent pipe. A connecting valve and a bypass valve are installed on the main discharge pipe.

9. The sulfur dioxide detection device for blast furnace gas before and after fine desulfurization according to claim 5 or 8, characterized in that, The SO2 and O2 detection devices are extraction-type detection devices.

10. The sulfur dioxide detection device for blast furnace gas before and after fine desulfurization according to claim 5 or 8, characterized in that, The specific steps of the sulfur dioxide detection method using the aforementioned sulfur dioxide detection device are as follows: (1) Turn on the main power supply, air inlet and combustion gas exhaust valve of the blast furnace gas combustion device, turn on the preheating switch to start the preheating device, and complete the preheating when the preheating temperature rises to 55~70℃; (2) After preheating, close the pre-desulfurization vent valve, the post-desulfurization primary ball valve and the post-desulfurization secondary ball valve in sequence, and close the connecting valve; open the post-desulfurization vent valve, open the pre-desulfurization primary ball valve and the pre-desulfurization secondary ball valve; and turn on the air blower to discharge air into the blast furnace gas combustion device. (3) Adjust the gas pressure reducing device and the air pressure reducing device to control the pressure entering the combustion chamber to 1.20~3.500Kpa, open the ignition device of the combustion chamber, open the gas flow valve set in the gas flow meter and the air flow valve set in the air flow meter to complete the normal ignition of the blast furnace gas and generate the combustion gas before desulfurization. (4) Turn on the main power supply and bypass valve of the SO2 and O2 detection device, start the SO2 and O2 detection device, and after the combustion gas generated before desulfurization after combustion in step (3) is stably discharged, open the connecting valve, close the bypass valve, close the combustion gas vent valve, and start detecting the sulfur dioxide concentration and oxygen concentration after combustion of the gas before fine desulfurization of blast furnace gas. (5) After obtaining the detection results of SO2 and O2 content of combustion gas before desulfurization in step (4), close the desulfurization exhaust valve in sequence, open the desulfurization primary ball valve and the desulfurization secondary ball valve, close the desulfurization primary ball valve and the desulfurization secondary ball valve, open the desulfurization exhaust valve, and continuously discharge air into the blast furnace gas combustion device. (6) Combust the desulfurized blast furnace gas to obtain desulfurized combustion gas, and then vent it into the air; (7) After the venting in step (6) continues for 10~15s, the venting is turned off and the desulfurized combustion gas is discharged into the SO2 and O2 detection device to detect the SO2 and O2 content in the desulfurized combustion gas and obtain the detection results of SO2 and O2 content in the desulfurized combustion gas. (8) Analyze the test results. For example, if the SO2 content in the desulfurized combustion gas is less than the SO2 content in the combustion gas before desulfurization, and the SO2 content in the desulfurized combustion gas is 80~150 mg / Nm³, then... 3 If the O2 content is 5%~8%, it proves that the blast furnace gas desulfurization is effective; otherwise, the blast furnace gas desulfurization is considered to be ineffective, and the blast furnace gas desulfurization device should be inspected.

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