Prejudgment method for ignition point temperature of activated carbon in sintering desulfurization and denitrification system

Abstract

The invention relates to the technical field of sintering, in particular to a pre-judging method for the ignition point temperature of activated carbon in a sintering desulfurization and denitrification system. And pre-judging the ignition point temperature of the activated carbon in the sintering desulfurization and denitrification system by taking the initial ignition point temperature of the new activated carbon, the oxygen content in the sintering flue gas, the cycle index of the activated carbon in the sintering desulfurization and denitrification system and the concentrations of Na, K and Cl elements in the sintering flue gas as evaluation parameters. By pre-judging the temperature of the ignition point of the activated carbon in the operation process of the sintering smoke desulfurization and denitrification system, high-temperature spontaneous combustion of the activated carbon in the subsequent process can be effectively prevented, the cycle index of the activated carbon is increased to the maximum extent, the consumption of the activated carbon is reduced, the cost is reduced, and system potential safety hazards caused by the fact that the high-temperature activated carbon is not found are avoided; and a guarantee is provided for the operation safety of the whole flue gas purification system.

Description

Technical Field

[0001] This invention relates to the field of sintering technology, and more particularly to a method for predicting the ignition temperature of activated carbon in a sintering desulfurization and denitrification system. Background Technology

[0002] In 2018, my country formulated the "Work Plan for Ultra-Low Emission Transformation of Iron and Steel Enterprises (Draft for Comments)," which clearly stipulates that SO2 in sintering flue gas should be <35 mg / m³. 3 NOx < 50 mg / m³ 3 Particulate matter <10mg / m³ 3 Article 43 of the "Law of the People's Republic of China on the Prevention and Control of Atmospheric Pollution" clearly stipulates that steel and other enterprises should adopt clean production processes and construct supporting dust removal, desulfurization, and denitrification devices, or take other measures such as technological upgrades to control air pollutant emissions, in order to control sulfides, nitrogen oxides, and dust emitted during the production process. Therefore, strengthening the comprehensive treatment of sintering flue gas is a necessary condition for the development and survival of steel enterprises.

[0003] Integrated activated carbon desulfurization and denitrification technology boasts advantages such as high removal efficiency, zero waste generation, and the ability to synergistically treat multiple pollutants. Therefore, it has been widely used in sintering flue gas treatment, especially in steel enterprises in northern my country. Activated carbon desulfurization and denitrification primarily rely on activated carbon to remove SO₂. x NO x The SO₂ is absorbed into its own micropores, and then removed through desorption and ammonia injection. x NO x Processing, SO x It is eventually made into sulfuric acid, NO x Ultimately, it reacts with ammonia to produce N2. Therefore, the micropores of activated carbon are crucial to the operation of this process.

[0004] Once the micropores of activated carbon become clogged, the permeability of the desulfurization and denitrification purification tower deteriorates, making it difficult for sintering waste gas to pass through the activated carbon in each bed layer. This is also known as activated carbon "poisoning." Since the sintering flue gas itself carries heat, typically at a temperature of 120-145℃, the local temperature will rise sharply after the permeability deteriorates, eventually reaching the ignition point of the activated carbon and threatening the safety of the entire desulfurization and denitrification system.

[0005] Patent 202111264727.7 discloses an adsorption tower and method for suppressing the spontaneous combustion of activated carbon for desulfurization and denitrification. The adsorption tower includes a tower body, and the inner cavity of the tower body is provided with an annular baffle that slopes downwards on the inner side. The outer edge of the annular baffle is connected to the inner surface of the tower body. In this method, the annular baffle, which slopes downwards on the inner side of the tower body, causes the activated carbon to change from its original state to a more compressed state when it moves from top to bottom into the area of ​​the annular baffle. After passing through the annular baffle, the activated carbon changes from a more compressed state to a more dispersed state, thereby improving its permeability and thus suppressing the spontaneous combustion of the activated carbon for desulfurization and denitrification. Patent 201910968750.0 discloses a method and device for controlling the temperature of an activated carbon desulfurization adsorption tower. The method acquires the temperature values ​​at each temperature monitoring point in the adsorption tower in real time, calculates the heating rate of each temperature monitoring point based on the acquired temperature values, and when the heating rate of at least one temperature monitoring point meets the preset warning conditions, the risk level of the adsorption tower is judged according to the preset correspondence between the rate and the level. Finally, the control operation corresponding to the hit risk level is executed to control the temperature of the adsorption tower. Patent 202110419689.1 discloses a method for temperature control in a multi-pollutant treatment process for sintering flue gas. The method includes the following steps: 1) Sintering flue gas is desulfurized by activated carbon adsorption in a desulfurization tower and then enters a denitrification tower, where it is further denitrified by activated carbon adsorption and then enters a dechlorination tower, finally being discharged from the dechlorination tower; 2) Activated carbon circulates between a desorption tower, a screening system, a denitrification tower, and a desulfurization tower; a detection device is installed at the inlet of the desulfurization tower to acquire the state data of the sintering flue gas at the inlet of the desulfurization tower; the state data of the sintering flue gas includes the total flow rate of the sintering flue gas and the concentration of each gas component in the sintering flue gas, thereby determining the mass of the circulating activated carbon; based on the adsorption capacity of the activated carbon for each gas and the initial concentration of each gas, the temperature range when the sintering flue gas enters the denitrification tower and the dechlorination tower is calculated.

[0006] The existing technologies mentioned above mainly suppress the spontaneous combustion of activated carbon for desulfurization and denitrification from the perspective of process control, but the risk of spontaneous combustion of activated carbon still exists. Therefore, there is an urgent need to provide a more effective means to prevent spontaneous combustion of activated carbon. Summary of the Invention

[0007] This invention provides a method for predicting the ignition temperature of activated carbon in a sintering desulfurization and denitrification system, thereby avoiding high-temperature spontaneous combustion of activated carbon in subsequent processes. This also avoids the system safety hazards caused by the failure to detect high-temperature activated carbon in the lower part of the front and middle chambers in the prior art, and provides a guarantee for the safety of the adsorption tower and even the entire flue gas purification system.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: A method for predicting the ignition temperature of activated carbon in a sintering desulfurization and denitrification system is proposed. The method uses the initial ignition temperature of new activated carbon, the oxygen content in the sintering flue gas, the number of activated carbon cycles in the sintering desulfurization and denitrification system, and the concentrations of Na, K, and Cl elements in the sintering flue gas as evaluation parameters. The following formula is used to predict the ignition temperature of activated carbon in the sintering desulfurization and denitrification system: When θ≤6

[0009] When 6 < θ ≤ 10

[0010] In the formula: T is the instantaneous ignition temperature (°C) of activated carbon in the sintering desulfurization and denitrification system. T0 is the initial ignition temperature (°C) of the new activated carbon. C0 represents the oxygen content (%) in the sintering flue gas. θ represents the number of activated carbon cycles in the sintering desulfurization and denitrification system; C Na The concentration of Na element in sintering flue gas (mg / m³) 3 ); C K The concentration of potassium (mg / m³) in sintering flue gas 3 ); C Cl The concentration of Cl element in sintering flue gas (mg / m³) 3 ).

[0011] In the above technical solution, the initial ignition temperature T0 of the new activated carbon is further measured in accordance with GB / T7702.9-2008 "Test Method for Ignition Point of Coal-based Granular Activated Carbon".

[0012] In the above technical solution, the oxygen content in the sintering flue gas further satisfies the following condition: 12% ≤ C0 ≤ 21%.

[0013] In the above technical solution, the Na element concentration in the sintering flue gas further satisfies the following condition: 0 ≤ C Na ≤10.

[0014] In the above technical solution, the concentration of potassium (K) in the sintering flue gas further satisfies the following condition: 0 ≤ C K ≤15.

[0015] In the above technical solution, the concentration of Cl in the sintering flue gas further satisfies the following condition: 0 ≤ C Cl ≤15.

[0016] The beneficial effects of this invention are as follows: By calculating the ignition point temperature of activated carbon during the operation of the sintering flue gas desulfurization and denitrification system, it is possible to effectively prevent high-temperature spontaneous combustion of activated carbon in subsequent processes, maximize the number of activated carbon cycles, reduce the amount of activated carbon used, lower costs, and avoid system safety hazards caused by undetected high-temperature activated carbon, thus ensuring the safety of the entire flue gas purification system. Detailed Implementation

[0017] The following examples are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0018] This invention provides a method for predicting the ignition point temperature of activated carbon in a sintering desulfurization and denitrification system, specifically including the following steps: (1) The initial ignition temperature T0 of new activated carbon shall be measured in accordance with GB / T7702.9-2008 "Test Method for Ignition Point of Coal-based Granular Activated Carbon"; (2) Determine the oxygen content in the sintering flue gas; (3) Collect the number of activated carbon cycles in the sintering desulfurization and denitrification system; (4) Determine the concentrations of Na, K, and Cl elements in the sintering flue gas; (5) Using the initial ignition temperature of new activated carbon, the oxygen content in the sintering flue gas, the number of activated carbon cycles in the sintering desulfurization and denitrification system, and the concentrations of Na, K, and Cl elements in the sintering flue gas as evaluation parameters, the following formula is used to predict the ignition temperature of activated carbon in the sintering desulfurization and denitrification system: When θ≤6

[0019] When 6 < θ ≤ 10

[0020] In the formula: T is the instantaneous ignition temperature (°C) of activated carbon in the sintering desulfurization and denitrification system. T0 is the initial ignition temperature (°C) of the new activated carbon. C0 represents the oxygen content (%) in the sintering flue gas. θ represents the number of activated carbon cycles in the sintering desulfurization and denitrification system; C Na The concentration of Na element in sintering flue gas (mg / m³) 3 ); C K The concentration of potassium (mg / m³) in sintering flue gas 3 ); C Cl The concentration of Cl element in sintering flue gas (mg / m³) 3 ); The oxygen content in the sintering flue gas must meet the following condition: 12% ≤ C0 ≤ 21%. The Na concentration in the sintering flue gas satisfies the following condition: 0 ≤ C Na ≤10; The concentration of potassium (K) in the sintering flue gas satisfies the following condition: 0 ≤ C K ≤15; The concentration of Cl in the sintering flue gas satisfies the following condition: 0 ≤ C Cl ≤15.

[0021] Examples 1-5 A steel plant with 405m 2 Taking the sintering machine as an example, the thickness of the base material laid on the sintering trolley ranges from 40mm, the thickness of the sintering material layer ranges from 850 to 950mm, the ignition temperature ranges from 950 to 1050℃, the ignition time ranges from 1.0 to 2.0 minutes, the ignition negative pressure ranges from 4.0 to 5.0 kPa, the sintering machine speed ranges from 1.75 to 1.85 m / min, the sintering exhaust negative pressure is 14 to 17 kPa, and the exhaust flow rate is 55-90 m³ / min. 3 The sintering machine system has an air leakage rate of 38.6-45% per minute. The sintering flue gas treatment system is a counter-current activated carbon desulfurization and denitrification (CSCR) system.

[0022] The data collected during the sintering process are shown in Table 1.

[0023] Table 1 Data collected during sintering production

[0024] The method of the present invention was used to predict the ignition point temperature of activated carbon. The comparison between the predicted value and the actual detected value is shown in Table 2.

[0025] Table 2 Comparison of predicted and measured values ​​of ignition point temperature of activated carbon

[0026] The method of this invention uses a method where the predicted ignition point temperature of activated carbon deviates by no more than 1% from the actual detected value. This results in high prediction accuracy, maximizes the number of activated carbon cycles, reduces the amount of activated carbon used, lowers costs, and avoids system safety hazards caused by undetected high-temperature activated carbon, thus ensuring the safety of the entire flue gas purification system.

[0027] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In the above embodiments of the present invention, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments. It should be understood that the disclosed technical content in the several embodiments provided in this application can be implemented in other ways.

Claims

1. A method for predicting the ignition point temperature of activated carbon in a sintering desulfurization and denitrification system, characterized in that, Using the initial ignition temperature of new activated carbon, the oxygen content in the sintering flue gas, the number of activated carbon cycles in the sintering desulfurization and denitrification system, and the concentrations of Na, K, and Cl elements in the sintering flue gas as evaluation parameters, the following formula is used to predict the ignition temperature of activated carbon in the sintering desulfurization and denitrification system: When θ≤6 When 6 < θ ≤ 10 In the formula: T is the instantaneous ignition temperature (°C) of activated carbon in the sintering desulfurization and denitrification system. T0 is the initial ignition temperature (°C) of the new activated carbon. C0 represents the oxygen content (%) in the sintering flue gas. θ represents the number of activated carbon cycles in the sintering desulfurization and denitrification system; C Na The concentration of Na element in sintering flue gas (mg / m³) 3 ); C K The concentration of potassium (mg / m³) in sintering flue gas 3 ); C Cl The concentration of Cl element in sintering flue gas (mg / m³) 3 ).

2. The prediction method according to claim 1, characterized in that, The initial ignition temperature T0 of the new activated carbon was measured according to GB / T7702.9-2008 "Test Method for Ignition Point of Coal-based Granular Activated Carbon".

3. The prediction method according to claim 1, characterized in that, The oxygen content in the sintering flue gas must meet the following condition: 12% ≤ C0 ≤ 21%.

4. The prediction method according to claim 1, characterized in that, The Na concentration in the sintering flue gas satisfies the following condition: 0 ≤ C Na ≤10.

5. The prediction method according to claim 1, characterized in that, The concentration of potassium (K) in the sintering flue gas satisfies the following condition: 0 ≤ C K ≤15.

6. The prediction method according to claim 1, characterized in that, The concentration of Cl in the sintering flue gas satisfies the following condition: 0 ≤ C Cl ≤15.

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