A method for assessing the effectiveness of in situ desorption of activated coke.

Abstract

The present application belongs to the technical field of desulfurization and denitrification by activated coke, specifically, to a method for evaluating the on-site desorption effect of activated coke. The method for evaluating the on-site desorption effect of activated coke described in this application combines a laboratory simulation desorption process to evaluate the on-site desorption effect of activated coke, respectively measuring the sulfur content of activated coke samples before and after on-site desorption and after laboratory simulation desorption, respectively calculating the desorption rate R of activated coke, and further realizing the evaluation of the on-site desorption effect of activated coke, thereby ensuring the effect of recycling activated coke, solving the problem of inaccurate evaluation of the on-site desorption effect of activated coke, and providing important guidance for on-site process optimization control.

Description

[Technical field]

[0001] The present application belongs to the technical field of desulfurization and denitrification using activated coke, and specifically relates to a method for evaluating the on-site desorption effect of activated coke.

[0002] This application claims priority to a Chinese patent application bearing application number 202211461771.1 and entitled "Method for assessing the in-situ desorption effect of activated coke" filed with the China Patent Office on November 16, 2022, the entire contents of which are incorporated herein by reference. [Background technology]

[0003] The desulfurization and denitrification technology using activated coke utilizes the adsorption and catalytic functions of activated coke to remove SO from flue gas. 2 , NO x It is a dry flue gas treatment technology that removes various pollutants such as particulate matter, mercury, dioxins, furans, heavy metals, and volatile organics in one go. Activated coke desulfurization and denitrification technology has a high pollutant removal effect, low energy consumption, no white smoke, and by-products can be recycled as resources, making it an economical and effective flue gas purification technology with great future prospects. In recent years, the activated coke desulfurization and denitrification process has been widely used in the sintering, pelletizing, coking and other processes of steel enterprises, and has achieved excellent results in terms of flue gas purification, solid waste reduction, resource recovery, etc. The activated coke desulfurization and denitrification process in China was launched early and has gradually been widely applied since 2018, but due to the short application period, there are still many challenges for the activated coke process in actual production. In the nearly 100 operating units, problems such as active coke ignition, crystallization and material accumulation in the ammonia-air mixing zone, corrosion of steel structures, and blockage of the material circulation system frequently occurred, bringing major challenges to stable production and ultra-low emissions.

[0004] Activated coke for desulfurization and denitrification is a porous carbon-containing material made from coal. It has a large specific surface area, a rich pore structure, and is characterized by pressure resistance, impact resistance, and abrasion resistance. In the desulfurization and denitrification process, activated coke absorbs SO through its pores in the adsorption tower. 2 It physically and chemically adsorbs NO and utilizes surface active groups. x and N.H. 3 catalyzes the SCR (Selective Catalytic Reduction) reaction of N 2 The activated coke with saturated adsorption enters the regeneration tower, where the adsorbed substances are removed at a high temperature of about 400 °C, after which the adsorption capacity is restored and it enters the adsorption tower again for the next adsorption. However, in the flue gas desulfurization and denitrification system using activated coke, although the activated coke can be used repeatedly, the effect of repeated use of the activated coke that has adsorbed various pollutants depends on the quality of the desorption process. Furthermore, since it is reused after the desorption process, the desorption effect of the activated coke is very important for the stable operation of the flue gas desulfurization and denitrification system. The desorption process refers to heating the activated coke to 400 °C or more under the protection of nitrogen gas to release the sulfur and ammonium salts adsorbed on the activated coke, thereby realizing the recovery of the desulfurization and denitrification functions. Research has shown that the differences in performance effects when the activated coke is repeatedly applied are all somehow related to the poor desorption effect of the activated coke. Furthermore, in actual production, the desorption effect of activated coke will fluctuate to a certain extent due to changes in on-site process conditions, which will have a significant impact on the purification effect of flue gas and the stable operation of the equipment, but currently there is no method for evaluating the desorption effect of activated coke. The relevant technology in the current market focuses on the design of on-site production equipment, and there are no relevant research reports on the evaluation of the desorption effect of activated coke in use.

[0005] In the desorption process of activated coke, ammonium salt particles can generally achieve rapid decomposition at 300 ° C, so the main limiting factor in the desorption process of activated coke is the release of sulfur, and therefore the desorption rate of sulfur during production is taken as the evaluation index of the desorption effect. The sulfur in activated coke contains decomposable sulfur and fixed sulfur, of which decomposable sulfur mainly contains sulfuric acid, ammonium sulfate, etc., and can be fully released during the desorption process, and fixed sulfur is mainly calcium sulfate, potassium sulfate, etc., that is, it is generated by sulfur after adsorption by activated coke and calcium-containing dust in flue gas, and its decomposition temperature is above 1200 ° C and is not decomposed during the desorption process. The sulfur content after desorption can be determined by normal sampling and detection, but the measurement of fixed sulfur among them is difficult, so the desorption rate cannot be calculated and the desorption effect of activated coke cannot be effectively evaluated. Therefore, it is of positive significance to develop a method to evaluate the desorption effect of activated coke, especially a method to effectively evaluate the in-situ desorption effect of activated coke. Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the technical problem to be solved by the present application is to provide a method for evaluating the on-site desorption effect of activated coke based on laboratory evaluation, which can measure the decomposable sulfur and fixed sulfur in activated coke, and can realize the evaluation of the on-site desorption effect of activated coke through data comparison, thereby solving the problem of inaccurate evaluation of the desorption effect of activated coke reused on-site, and providing important guidance for on-site process optimization control. [Means for solving the problem]

[0007] In order to solve the above technical problems, the method for evaluating the in-situ desorption effect of activated coke described in the present application includes: (1) grinding the activated coke sample 1 before on-site desorption into powder and measuring its sulfur content, denoted as S1 (in %); (2) grinding the activated coke sample 2 after in situ desorption into a powder and measuring its sulfur content, denoted as S2 (in %); (3) performing a desorption experiment using the activated coke sample 1 according to the operation parameters of the on-site desorption operation, collecting the activated coke sample 3 after the desorption experiment and grinding it into powder, and measuring the sulfur content thereof, which is defined as a fixed sulfur content S3 (unit: %); The desorption rate R of activated coke is defined as the ratio of desorbable sulfur in activated coke desorbed by the on-site desorption tower, and is calculated from S1, S2, and S3 using the following formula: (4) calculating the desorption rate R of the activated coke according to the method of the present invention; and (5) evaluating the in-situ desorption effect of the activated coke based on the calculated value of the desorption rate R of the activated coke.

[0008] Specifically, in the steps (1), (2), and (3), a carbon-sulfur analyzer is used for the measurement in the step of measuring the sulfur content.

[0009] Specifically, in the above steps (1), (2), and (3), the pulverizing steps control the powder particle size to 100 mesh or less, individually.

[0010] Specifically, in the steps (1) and (2), the amounts of the activated coke sample 1 and the activated coke sample 2 used are the same.

[0011] Specifically, in the step (3), the desorption experiment is carried out using a tubular furnace.

[0012] Specifically, in the step (3), the parameters of the desorption experiment include a desorption time of 40 min or more, a desorption temperature of 440° C., and a nitrogen gas flow rate of 40 to 60 L / h.

[0013] Specifically, in the method for evaluating the in-situ desorption effect of activated coke, in the step (5), the evaluation step includes: If the calculated desorption rate R is less than 90%, the desorption of the activated coke is evaluated as insufficient, and the process parameters of the on-site desorption tower are adjusted. Step a) is to take new samples and repeat steps (1) to (4) until the measured R is 90% or more; and b) if the calculated desorption rate R is 90% or more, evaluating that the desorption effect can meet the process requirements, and there is no need to change the in-situ desorption parameters.

[0014] Specifically, in the step (5), adjusting the process parameters of the in-situ desorption tower includes adjusting the desorption temperature, adjusting the nitrogen gas flow rate, and / or adjusting the desorption time.

[0015] Specifically, the step (5) further includes taking a new sample at least 3 hours after the process parameters of the in-situ desorption tower have been adjusted and stabilized, and repeating steps (1) to (4).

[0016] The present application also discloses the use of the method for evaluating the in situ desorption effect of activated coke in evaluating the performance of the activated coke. Effect of the Invention

[0017] The method for evaluating the in-situ desorption effect of activated coke described in this application combines a laboratory simulation desorption process to evaluate the in-situ desorption effect of activated coke, which can not only measure the decomposable sulfur and fixed sulfur in activated coke, but also realize the evaluation of the in-situ desorption effect of activated coke through data comparison. By enabling the evaluation of the in-situ desorption effect of activated coke, the effect of recycling activated coke is ensured, the problem of inaccurate evaluation of the in-situ desorption effect of activated coke is solved, and important guidance is provided for on-site process optimization control. [Brief description of the drawings]

[0018] In order to make the contents of the present application easier to understand clearly, the present application will be described in more detail below based on specific examples of the present application with reference to the drawings.

[0019] [Figure 1] Schematic diagram of the operation of the method for evaluating the desorption effect of activated coke. Sample 1 is the activated coke before in-situ desorption, sample 2 is the activated coke after in-situ desorption, and sample 3 is the activated coke after laboratory desorption, where the sulfur content S1 is the percentage of the sulfur content of the activated coke before in-situ desorption, the sulfur content S2 is the percentage of the sulfur content of the activated coke after in-situ desorption, and the sulfur content S3 is the percentage of the sulfur content of the activated coke after laboratory desorption. [Diagram 2] This is an experimental device for simulating activated coke desorption. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In the following examples of the present application, a horizontal tube furnace shown in FIG. 2 is used as a simulation experimental device for the laboratory simulation desorption experiment of the activated coke sample.

[0021] In the horizontal tubular furnace shown in Fig. 2, a desorption simulation experiment is carried out by introducing protective nitrogen into the horizontal tubular furnace. An activated coke sample is placed in the constant temperature zone 3, which is the activated coke-filled area inside the reaction tube 4, and nitrogen is controlled to enter the reaction tube 4 from the inlet 1 and exhaust from the exhaust port 5 of the reaction tube 4. In the desorption experiment, the temperature of the experiment is controlled by the heating element 2, and the reaction parameters are controlled by the control panel 6. The desorption simulation experiment of the activated coke sample is completed.

[0022] In the following embodiment of the present application, in the step of detecting each activated coke sample using a carbon / sulfur analyzer, the mode conditions of the carbon / sulfur analyzer are followed, and the detection parameters and conditions for different samples are controlled to be the same. EXAMPLES

[0023] Example 1 As shown in the operational flow chart in FIG. 1, the method for evaluating the in-situ desorption effectiveness of activated coke described in this example includes the following steps. (1) An activated coke sample 1 before desorption was collected on-site, 30 g was weighed out, and crushed to a powder of 100 mesh or less. The sulfur content S1 was measured using a carbon-sulfur analyzer, and the sulfur content S1 was 3.52%. (2) After desorption, activated coke sample 2 was collected on-site, 30 g was weighed out, and crushed to a powder of 100 mesh or less. The sulfur content S2 was measured using a carbon-sulfur analyzer, and the sulfur content S2 was found to be 2.11%. (3) A desorption experiment was carried out on the activated coke sample 1 using the tubular furnace shown in Figure 2, and the experimental parameters were as follows: the amount of activated coke used was 40 g, and the desorption time, desorption temperature, and nitrogen gas flow rate were 40 min, 440 °C, and 40 L / h, respectively. The activated coke sample 3 after desorption was obtained by the above desorption experiment, 30 g was weighed out, crushed into powder of 100 mesh or less, and its sulfur content S3 was measured by a carbon-sulfur analyzer, which was 1.65%. The sulfur content after desorption under these parameter conditions is defined as the fixed sulfur content. (4) The desorption rate R of the activated coke was defined as the proportion of desorbable sulfur in the activated coke desorbed by the on-site desorption tower. The desorption rate R of the activated coke was calculated from S1, S2, and S3 using the following formula, and the desorption rate R was 75.4%.

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[0024] Example 2 As shown in the operation flow chart in FIG. 1, the method for evaluating the in-situ desorption effect of activated coke described in this example includes the following steps: (1) An activated coke sample 1 before desorption was collected on-site, 30 g was weighed out, and crushed to a powder of 100 mesh or less. The sulfur content S1 was measured using a carbon-sulfur analyzer, and the sulfur content S1 was 4.02%. (2) After desorption, activated coke sample 2 was collected on-site, 30 g was weighed out, crushed into powder, and its sulfur content S2 was measured using a carbon-sulfur analyzer. The sulfur content S2 was 1.95%. (3) A desorption experiment was carried out on the activated coke sample 1 using the tubular furnace shown in Figure 2, and the experimental parameters were as follows: the amount of activated coke used was 40 g, and the desorption time, desorption temperature, and nitrogen gas flow rate were 40 min, 440 °C, and 40 L / h, respectively. The activated coke sample 3 after desorption was obtained by the above desorption experiment, 30 g of which was weighed out and crushed into powder of 100 mesh or less, and its sulfur content S3 was measured by a carbon-sulfur analyzer, which was 1.72%. The sulfur content after desorption under these parameter conditions is defined as the fixed sulfur content. (4) The desorption rate R of the activated coke was defined as the proportion of desorbable sulfur in the activated coke desorbed by the on-site desorption tower. The desorption rate R of the activated coke was calculated from S1, S2, and S3 using the following formula, and the desorption rate R was 90%.

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[0025] Example 3 As shown in the operation flow chart in FIG. 1, the method for evaluating the in-situ desorption effect of activated coke described in this example includes the following steps: (1) An activated coke sample 1 before desorption was collected on-site, 30 g was weighed out, and crushed to a powder of 100 mesh or less. The sulfur content S1 was measured using a carbon-sulfur analyzer, and the sulfur content S1 was 3.97%. (2) After desorption, activated coke sample 2 was collected on-site, 30 g was weighed out, and crushed to a powder of 100 mesh or less. The sulfur content S2 was measured using a carbon-sulfur analyzer, and the sulfur content S2 was found to be 2.03%. (3) A desorption experiment was carried out on the activated coke sample 1 using the tubular furnace shown in Figure 2, and the experimental parameters were as follows: the amount of activated coke used was 40 g, and the desorption time, desorption temperature, and nitrogen gas flow rate were 40 min, 440 °C, and 40 L / h, respectively. The activated coke sample 3 after desorption was obtained by the above desorption experiment, 30 g was weighed out, crushed into powder of 100 mesh or less, and its sulfur content S3 was measured by a carbon-sulfur analyzer, which was 1.75%. The sulfur content after desorption under these parameter conditions is defined as the fixed sulfur content. (4) The desorption rate R of the activated coke was defined as the proportion of desorbable sulfur in the activated coke desorbed by the on-site desorption tower. The desorption rate R of the activated coke was calculated from S1, S2, and S3 using the following formula, and the desorption rate R was 87.4%.

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[0026] Example 4 As shown in the operation flow chart in FIG. 1, the method for evaluating the in-situ desorption effect of activated coke described in this example includes the following steps: (1) An activated coke sample 1 before desorption was collected on-site, 30 g was weighed out, and crushed to a powder of 100 mesh or less. The sulfur content S1 was measured using a carbon-sulfur analyzer, and the sulfur content S1 was 4.53%. (2) After desorption, activated coke sample 2 was collected on-site, 30 g was weighed out, and crushed to a powder of 100 mesh or less. The sulfur content S2 was measured using a carbon-sulfur analyzer, and the sulfur content S2 was found to be 2.23%. (3) A desorption experiment was carried out on the activated coke sample 1 using the tubular furnace shown in Figure 2, and the experimental parameters were as follows: the amount of activated coke used was 40 g, and the desorption time, desorption temperature, and nitrogen gas flow rate were 40 min, 440 °C, and 40 L / h, respectively. The activated coke sample 3 after desorption was obtained by the above desorption experiment, 30 g was weighed out, crushed into powder of 100 mesh or less, and its sulfur content S3 was measured by a carbon-sulfur analyzer, which was 1.83%. The sulfur content after desorption under these parameter conditions is defined as the fixed sulfur content. (4) The desorption rate R of the activated coke was defined as the proportion of desorbable sulfur in the activated coke desorbed by the on-site desorption tower. The desorption rate R of the activated coke was calculated from S1, S2, and S3 using the following formula, and the desorption rate R was 85.2%.

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[0027] Obviously, the above examples are merely examples for clear explanation, and do not limit the embodiments. Those skilled in the art may make various other changes or modifications based on the above description. It is not necessary or possible to comprehensively cover all the embodiments here. And, obvious changes or modifications derived therefrom still fall within the scope of protection of the present application. [Explanation of symbols]

[0028] 1 air inlet, 2 heating element, 3 constant temperature zone, 4 reaction tube, 5 exhaust, 6 control panel

Claims

1. 1. A method for evaluating in situ desorption effectiveness of activated coke, comprising: (1) crushing an activated coke sample 1 before on-site desorption into powder and measuring its sulfur content, designated as S1 (in %); (2) grinding the activated coke sample 2 after on-site desorption into powder and measuring its sulfur content, designated as S2 (in %); (3) performing a desorption experiment using the activated coke sample 1 according to the operation parameters of the on-site desorption operation, collecting the activated coke sample 3 after the desorption experiment and grinding it into powder, and measuring the sulfur content thereof, which is defined as a fixed sulfur content S3 (unit: %); The desorption rate R of the activated coke is defined as the ratio of desorbable sulfur in the activated coke desorbed by the on-site desorption tower, and is calculated from S1, S2, and S3 by the following formula: (4) calculating the desorption rate R of the activated coke by and (5) evaluating the in-situ desorption effectiveness of the activated coke based on the calculated value of the desorption ratio R of the activated coke.

2. 2. The method for evaluating the in-situ desorption effect of activated coke according to claim 1, wherein in steps (1), (2), and (3), a carbon and sulfur analyzer is used for the measurement in the step of measuring the sulfur content.

3. The method for evaluating the in-situ desorption effect of activated coke according to claim 1, characterized in that in the steps (1), (2), and (3), the grinding steps control the powder particle size to 100 mesh or less independently of each other.

4. 2. The method for evaluating the in-situ desorption effect of activated coke according to claim 1, wherein in steps (1) and (2), the amounts of activated coke sample 1 and activated coke sample 2 used are the same.

5. 2. The method for evaluating the in-situ desorption effect of activated coke according to claim 1, wherein in the step (3), the desorption experiment is carried out using a tube furnace.

6. The method for evaluating the in-situ desorption effect of activated coke according to claim 1, characterized in that in the step (3), the parameters of the desorption experiment include a desorption time of 40 min or more, a desorption temperature of 440° C., and a nitrogen flow rate of 40 to 60 L / h.

7. In the step (5), the evaluation step includes: If the calculated desorption rate R is less than 90%, the desorption of the activated coke is evaluated as insufficient, and the process parameters of the on-site desorption tower are adjusted. Then, a sample is taken again and steps (1) to (4) are repeated until the measured R is 90% or more. and b) if the calculated desorption rate R is 90% or more, evaluating that the desorption effect can meet the process requirements, and there is no need to change the in-situ desorption parameters.

8. The method for evaluating the in-situ desorption effect of activated coke as described in claim 7, characterized in that in step (5), the step of adjusting the process parameters of the in-situ desorption tower includes adjusting the desorption temperature, adjusting the nitrogen gas flow rate, and / or adjusting the desorption time.

9. The method for evaluating the in-situ desorption effect of activated coke according to claim 8, characterized in that the step (5) further comprises: taking a new sample at least 3 h after the process parameters of the in-situ desorption tower are adjusted and stabilized, and repeating steps (1) to (4).

10. Use of the method for evaluating the in-situ desorption effect of activated coke according to any one of claims 1 to 9 in evaluating the performance of activated coke.

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