A method and apparatus for mild oxidative stabilization of spent desulfurizer

Abstract

This invention relates to the field of waste desulfurizing agent treatment technology, specifically to a method and apparatus for the mild oxidation stabilization of waste desulfurizing agent, comprising the following steps: Step 1: Loading new desulfurizing agent, weighing the new desulfurizing agent and loading it into a storage tank and sealing it; Step 2: Running the desulfurization process; Step 3: After the desulfurizing agent in the desulfurization unit is saturated, closing the process desulfurization valve system, starting the waste desulfurizing agent stabilization valve system, and introducing air velocity of 100-300 h⁻¹ into the storage tank. ‑1 The process involves five steps: Step 1: Precisely controlling the air velocity to allow the waste desulfurizer to undergo a slow oxidation reaction with oxygen, generating and stabilizing elemental sulfur. Step 2: Precisely controlling the air velocity allows the waste desulfurizer to slowly oxidize with oxygen, generating and stabilizing elemental sulfur, thus reducing the risk of spontaneous combustion and minimizing environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of waste desulfurizing agent treatment technology, specifically to a method and apparatus for the mild oxidation stabilization of waste desulfurizing agents. Background Technology

[0002] Desulfurizing agents, including iron oxide, are chemical substances used to remove sulfides from industrial waste gases. They are widely used in coal-fired power plants, steel smelting, and chemical production. Their main function is to convert harmful gases such as sulfur dioxide and hydrogen sulfide in waste gases into harmless or low-toxicity substances through chemical reactions, thereby reducing sulfide emissions. During use in desulfurization towers, the active component, iron oxide, reacts with sulfides to form iron sulfide, rendering the agent ineffective. The color changes from reddish-brown to dark brown due to the accumulation of large amounts of iron sulfide inside. Iron sulfide is highly oxidizable, and when used desulfurizing agents are removed from the tower, they are prone to spontaneous combustion in air, producing large amounts of sulfur dioxide and other gases with pungent odors. Extinguishing the fire with water will also generate a large amount of wastewater. Therefore, the disposal of used desulfurizing agents has a significant environmental impact. Currently, used desulfurizing agents are generally disposed of through direct stockpiling or deep burial.

[0003] While direct dumping and deep burial are simple and crude methods, waste desulfurizing agents are highly susceptible to spontaneous combustion during open-air storage or simple landfilling. This increases safety risks for personnel and causes severe air pollution, frequently leading to complaints and environmental disputes from nearby residents. Furthermore, rainwater can cause the uncontrolled seepage of sulfur- and iron-containing pollutants, severely polluting the surrounding soil and groundwater. Therefore, this method not only violates environmental regulations but also poses significant environmental and safety risks.

[0004] Therefore, there is an urgent need for a treatment method that can render waste desulfurizing agents harmless, effectively suppress the release of irritating gases, and stabilize the waste desulfurizing agents. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method and apparatus for the mild oxidation stabilization of waste desulfurizing agent, which solves the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for mild oxidative stabilization of waste desulfurizing agent, comprising the following steps:

[0007] Step 1: Filling with new desulfurizing agent. Weigh the new desulfurizing agent and fill it into the storage tank and seal it.

[0008] Step 2: Desulfurization process operation;

[0009] Step 3: After the desulfurizing agent in the desulfurization unit is saturated, close the process desulfurization valve system, start the waste desulfurizing agent stabilization valve system, and introduce air into the storage tank, controlling the air velocity to 100-300 h⁻¹.-1 This causes the iron sulfide in the waste desulfurizing agent to undergo a slow oxidation reaction with oxygen, producing iron oxide and elemental sulfur.

[0010] Step 4: Monitor the temperature of the storage tank in real time;

[0011] Step 5: Cleaning up the stabilized waste desulfurizing agent. After the stabilization process is completed, stabilized waste desulfurizing agent is obtained. The stabilized waste desulfurizing agent is cleaned up to prepare for the filling of the next batch of new desulfurizing agent.

[0012] Preferably, in step three, the airspeed is controlled to be 114-190 h. -1 .

[0013] Preferably, in step three, air is introduced from the bottom of the storage tank and discharged from the top of the storage tank.

[0014] Preferably, in step three, air is introduced from the top of the storage tank and discharged from the bottom of the storage tank.

[0015] Preferably, in step four, the temperature at at least one location inside the storage tank is monitored in real time.

[0016] Preferably, in step five, when the monitored temperature reaches its peak and begins to drop to near the initial temperature, the slow oxidation reaction is determined to be essentially complete.

[0017] Preferably, the exhaust gas discharged from the storage tank is passed into a carbon canister for treatment.

[0018] An apparatus for a mild oxidative stabilization method for waste desulfurizing agent, comprising:

[0019] Storage tank: Used to contain waste desulfurizing agent and to achieve gas flow direction of top inlet and bottom outlet or bottom inlet and top outlet;

[0020] The air supply and control unit, including an air compressor, a pressure reducing valve, and a ball valve, is used to control the air velocity between 100 and 300 h⁻¹. -1 ;

[0021] A rotor flow meter, connected downstream of the ball valve, is used to monitor and provide feedback on the air velocity;

[0022] Temperature monitoring unit: installed outside or inside the storage tank, used to monitor the oxidation reaction temperature inside the storage tank;

[0023] Activated carbon canister: Located at the gas outlet of the storage tank, it is filled with activated carbon to adsorb sulfur-containing gases in the exhaust gas.

[0024] Preferably, the temperature monitoring unit is an infrared thermometer.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. This invention enables waste desulfurizing agent to undergo a slow oxidation reaction with oxygen by precisely controlling the air velocity. Combined with a carbon canister, it can effectively treat and significantly reduce the fugitive emissions of irritating gases, thus solving the core environmental problem that leads to complaints from surrounding residents.

[0027] 2. By providing different air inlet directions (top or bottom) for the storage tank, this invention demonstrates that the bottom-in, top-out method can react the generated sulfur dioxide with unreacted iron sulfide or ferrous sulfide to generate chemically stable elemental sulfur and stabilize it, thereby reducing the risk of spontaneous combustion of waste desulfurizing agent.

[0028] 3. By monitoring the internal temperature of the storage tank in real time, this invention can determine the end time of the oxidation reaction, making it easy to achieve automated monitoring and management of the process. Attached Figure Description

[0029] Figure 1 This is a flowchart of the method in this invention;

[0030] Figure 2 This is a schematic diagram of the waste desulfurizing agent stabilization device in Embodiment 1 of the present invention;

[0031] Figure 3 This is a graph showing the oxidation reaction temperature of Example 1 in this invention;

[0032] Figure 4 This is a diagram illustrating the oxidation effect of waste desulfurizing agent in Example 1 of this invention.

[0033] Figure 5 This is a schematic diagram of the waste desulfurizing agent stabilization device of Comparative Example 1 in this invention.

[0034] Figure 6 This is a graph showing the oxidation reaction temperature of Comparative Example 1 in this invention.

[0035] Figure 7 This is a diagram showing the oxidation effect of waste desulfurizing agent in Comparative Example 1 of this invention;

[0036] Figure 8 This is a graph showing the oxidation reaction temperature of Comparative Example 2 in this invention.

[0037] Figure 9 This is a diagram illustrating the oxidation effect of the waste desulfurizing agent in Comparative Example 2 of this invention.

[0038] Figure 10 This is a graph showing the oxidation reaction temperature of Comparative Example 3 in this invention.

[0039] Figure 11 This is a diagram illustrating the oxidation effect of the waste desulfurizing agent in Comparative Example 3 of this invention.

[0040] Figure 12 This is a schematic diagram of the waste desulfurizing agent stabilization device of Comparative Example 4 in this invention.

[0041] Figure 13 This is a graph showing the oxidation reaction temperature of Comparative Example 4 in this invention;

[0042] Figure 14 This is a diagram showing the oxidation effect of the waste desulfurizing agent in Comparative Example 4 of this invention.

[0043] Figure 15 This is a graph showing the oxidation reaction temperature of Comparative Example 5 in this invention.

[0044] Figure 16 This is a diagram showing the oxidation effect of waste desulfurizing agent in Comparative Example 5 of this invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] Please see Figures 1-4 A method for mild oxidative stabilization of waste desulfurizing agent, comprising the following steps:

[0048] Step 1: Filling with new desulfurizing agent. Weigh the new desulfurizing agent and fill it into the storage tank and seal it.

[0049] Step 2: Desulfurization process operation;

[0050] Step 3: After the desulfurizing agent in the desulfurization unit is saturated, close the process desulfurization valve system, start the waste desulfurizing agent stabilization valve system, and introduce air into the storage tank, controlling the air velocity to 100-300 h⁻¹. -1 This causes the iron sulfide in the waste desulfurizing agent to undergo a slow oxidation reaction with oxygen, producing iron oxide and elemental sulfur.

[0051] Air is supplied to the storage tank from the output of the air compressor. In this embodiment, the air velocity is controlled at 252 h⁻¹ using a ball valve and a pressure reducing valve. -1 Space velocity refers to the volumetric flow rate of reactants passing through a unit volume of catalyst per unit time, and its calculation formula is:

[0052] in, h represents airspeed. -1 ; Volumetric flow rate, Nm 3 / h; The volume of the catalyst is expressed in m. 3 .

[0053] By checking the air velocity using a rotor flow meter, air enters from the bottom of the tank and exits from the top. Finally, the gas exiting from the top of the tank is piped into clean water.

[0054] Step 4: Monitor the temperature of the storage tank in real time;

[0055] Measure the tank temperature using a temperature monitoring unit located 150mm away from the tank and record the data. In this embodiment, the temperature monitoring unit is an infrared thermometer. Please refer to [link / reference needed]. Figure 3 The figure shows the oxidation reaction temperature curve for Example 1. Figure 3 It can be seen that from the start of the reaction to about 2 hours, the initial ambient temperature reached the highest temperature, that is, the peak temperature was 100-150℃. After that, the temperature dropped relatively slowly. During the entire experiment, the workshop had a strong pungent odor, indicating that the waste desulfurizing agent produced a large amount of sulfur dioxide gas due to the high temperature during the oxidation process.

[0056] Step 5: Cleaning up the stabilized waste desulfurizing agent. After the stabilization process is completed, stabilized waste desulfurizing agent is obtained. The stabilized waste desulfurizing agent is cleaned up to prepare for the filling of the next batch of new desulfurizing agent.

[0057] Once the temperature reaches its maximum, continue measuring. After the temperature drops to the initial ambient temperature, the oxidation reaction ends. Continue purging with air until the next day, then open the storage tank to check the oxidation effect of the waste desulfurizing agent. Please refer to... Figure 4 The image shows the oxidation effect of the waste desulfurizing agent in Example 1. It can be seen that most of the waste desulfurizing agent participated in the oxidation reaction and generated red iron oxide.

[0058] Comparative Example 1

[0059] Please see Figure 5-7 A method for mild oxidative stabilization of waste desulfurizing agent, comprising the following steps:

[0060] Steps one, two, and five are the same as in Example 1. The difference between step three and Example 1 is that in this example, the airspeed is controlled at 252 h⁻¹ using a ball valve and a pressure reducing valve. -1 The air velocity is checked by a rotor flow meter. Air enters from the top of the storage tank and exits from the bottom. The lower end of the storage tank is connected to the carbon canister, and the outlet of the carbon canister is inserted into clean water through a pipe.

[0061] Step 4: Monitor the temperature of the storage tank in real time;

[0062] Measure the temperature of the upper, middle, and lower parts of the tank using a temperature monitoring unit at a distance of 150mm from the tank, and record the data. In this embodiment, the temperature monitoring unit is an infrared thermometer. Please refer to [link to relevant documentation]. Figure 6 The figure shows the oxidation reaction temperature curve for Comparative Example 1. (The text abruptly ends here, likely due to an incomplete sentence or missing information.) Figure 6 It can be seen that the peak temperature of the oxidation reaction is 60-70℃, and then the temperature slowly decreases. During the entire experiment, there was a local irritating odor in the workshop.

[0063] Please see Figure 7 The figure shows the oxidation effect of the waste desulfurizer in Comparative Example 1. It can be seen that a small portion of the waste desulfurizer participated in the oxidation reaction. There are a few yellow substances on the surface of the waste desulfurizer, indicating that the oxidation reaction produced a small amount of elemental sulfur.

[0064] Compared with Example 1, the activated carbon inside the added carbon canister adsorbed some of the irritating gases, and the temperature of the entire oxidation reaction process was significantly lower than that of Example 1, thus reducing the emission of sulfur dioxide irritating gases.

[0065] Comparative Example 2

[0066] Please see Figures 8-9 The difference between this comparative example and Comparative Example 1 is that the airspeed in this comparative example is controlled at 153 h. -1 Other parameter settings and connection relationships are the same as in Comparative Example 1. Please refer to... Figure 8 As can be seen, the peak temperature of the oxidation reaction in this comparative example is 60-65℃, and there is a slight pungent odor during the oxidation process; please refer to [link / reference needed]. Figure 9 The image shows the oxidation effect of the waste desulfurizing agent in Comparative Example 2. It can be seen that there is a small amount of yellow substance on the surface of the waste desulfurizing agent, which indicates that a small amount of elemental sulfur was produced during the oxidation reaction.

[0067] Comparative Example 3

[0068] Please see Figures 10-11 The difference between this comparative example and Comparative Example 1 is that the airspeed in this comparative example is controlled at 114 h. -1 All other parameter settings and connection relationships are the same. Please refer to [link / reference]. Figure 10 It can be seen that the peak temperature of the oxidation reaction in this comparative example is 50-60℃, which is about 10℃ lower than that in Comparative Example 1, and no obvious irritating gas is produced during the oxidation reaction; please refer to Figure 11 The image shows the oxidation effect of the waste desulfurizing agent in Comparative Example 3. It can be seen that there is a large amount of yellow substance on the surface of the waste desulfurizing agent, which indicates that a large amount of elemental sulfur was produced during the oxidation reaction.

[0069] Please refer to Table 1, which is a comparison table of experimental parameters and effects for Example 1 and Comparative Examples 1-3:

[0070] Table 1. Comparison of experimental parameters and effects of Example 1 and Comparative Examples 1-3 Implementation / Comparative Example <![CDATA[Air speed (h -1 )]]> Peak temperature (°C) Do you have an activated carbon canister? Does it have a pungent odor? Does it produce elemental sulfur? Example 1 252 100-150 no It has a strong, pungent odor. no Comparative Example 1 252 60-70 yes There is an irritating odor in the affected area. small amount Comparative Example 2 153 60-65 yes It has a slight pungent odor. small amount Comparative Example 3 114 50-60 yes No obvious irritating odor large amount

[0071] As shown in Table 1, the charcoal canister can adsorb some irritating gases. When the space velocity is low, the oxidation reaction temperature is also relatively low. It can also reduce the generation of sulfur dioxide irritating gases and generate stable elemental sulfur.

[0072] Comparative Example 4

[0073] Please see Figures 12-14 The difference between this comparative example and Comparative Example 1 is that the airspeed is 190 h. -1 Air enters from the bottom of the storage tank and exits from the top; all other settings are the same. Please refer to [link / reference]. Figure 13 In this comparative example, the peak temperature of the oxidation reaction was 70-80℃, and the irritating gas was concentrated at the outlet of the activated carbon canister. This indicates that the activated carbon adsorption canister cannot completely adsorb the irritating gas, and the activated carbon in the canister needs to be replaced during the oxidation reaction. Please refer to [link to relevant documentation]. Figure 14 The figure shows the oxidation effect of the waste desulfurizer in Comparative Example 4. It can be seen that about half of the waste desulfurizer participated in the oxidation reaction and generated iron oxide. A small amount of yellow sulfur was also found to be generated during the oxidation reaction.

[0074] Comparative Example 5

[0075] Please see Figures 15-16 The difference between this comparative example and Comparative Example 4 is that air enters from the top of the storage tank and exits from the bottom. All other parameters are the same, and its schematic diagram is identical to that of Comparative Example 1. Please refer to... Figure 15 As can be seen, the peak temperature of the oxidation reaction in this embodiment is 90-100℃, and the odor is quite pungent; please refer to [link / reference]. Figure 16 The diagram shows the oxidation effect of the waste desulfurizing agent in this embodiment. It can be seen that most of the waste desulfurizing agent participates in the oxidation reaction and generates iron oxide. No obvious sulfur element is generated during the oxidation reaction.

[0076] Please refer to Table 2, which shows the experimental parameters and results for Comparative Examples 4-5:

[0077] Table 2. Comparison of experimental parameters and effects between Comparative Examples 4 and 5 Comparative Example <![CDATA[Airspeed (h -1 )]]> Peak temperature (°C) Storage tank air intake method Does it have a pungent odor? Does it produce elemental sulfur? 4 190 70-80 Bottom air intake The pungent odor was concentrated at the outlet of the charcoal canister. small amount 5 190 90-100 Top air intake Strong pungent odor no

[0078] Table 2 shows that, under the same space velocity and weight, the peak temperature of the oxidation reaction is significantly lower when the tank is inlet from the bottom and outlet from the top compared to the tank is inlet from the top and outlet from the bottom. Additionally, the amount of irritating gas is significantly reduced. This indicates that the tank is inlet from the bottom, resulting in a high temperature during the oxidation reaction and creating a chimney effect. The generated sulfur dioxide reacts with unreacted iron sulfide or ferrous sulfide to form elemental sulfur for stabilization. If the tank is inlet from the top and outlet from the bottom, the sulfur dioxide cannot reach the bottom and cannot react with iron sulfide or ferrous sulfide, and the oxidation reaction temperature will be extremely high.

[0079] In summary, sulfur dioxide is easily produced at higher oxidation reaction temperatures, and the space velocity is relatively low (114-190 h⁻¹). -1 When the oxidation reaction temperature is lowered, the oxidation reaction becomes milder and sulfur dioxide production is reduced, while stable elemental sulfur is generated. Similarly, when gas is introduced from the bottom and discharged from the top of the storage tank, the reaction between sulfur dioxide and unreacted iron sulfide or ferrous sulfide can be increased to generate elemental sulfur for stabilization. Therefore, the oxidation reaction of waste desulfurizing agent can be carried out in the desulfurization tower to stabilize the waste desulfurizing agent. When the waste desulfurizing agent is taken out of the desulfurization tower, the risk of spontaneous combustion and sulfur dioxide production are reduced, which meets environmental protection requirements and improves the safety of the treatment process.

[0080] Example 2

[0081] Please see Figure 2 , Figure 5 and Figure 12 An apparatus for a mild oxidative stabilization method for waste desulfurizing agent, comprising:

[0082] Storage tank: Used to contain waste desulfurizing agent and to achieve gas flow direction of top inlet and bottom outlet or bottom inlet and top outlet;

[0083] The air supply and control unit, including an air compressor, a pressure reducing valve, and a ball valve, is used to control the air velocity between 100 and 300 h⁻¹. -1 ;

[0084] A rotor flow meter, connected downstream of the ball valve, is used to monitor and provide feedback on the air velocity;

[0085] Temperature monitoring unit: installed outside or inside the storage tank, used to monitor the oxidation reaction temperature inside the storage tank. In this embodiment, the temperature monitoring unit is an infrared thermometer.

[0086] Activated carbon canister: Located at the gas outlet of the storage tank, it is filled with activated carbon. Figure 2 No charcoal canisters were installed. Figure 5 and Figure 12 All are equipped with carbon canisters to adsorb sulfur-containing gases in the exhaust gas.

[0087] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0088] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for mild oxidative stabilization of waste desulfurizing agent, characterized in that, Includes the following steps: Step 1: Filling with new desulfurizing agent. Weigh the new desulfurizing agent and fill it into the storage tank and seal it. Step 2: Desulfurization process operation; Step 3: After the desulfurizing agent in the desulfurization unit is saturated, close the process desulfurization valve system, start the waste desulfurizing agent stabilization valve system, and introduce air into the storage tank, controlling the air velocity to 100-300 h⁻¹. -1 This causes the iron sulfide in the waste desulfurizing agent to undergo a slow oxidation reaction with oxygen, producing iron oxide and elemental sulfur. Step 4: Monitor the temperature of the storage tank in real time; Step 5: Cleaning up the stabilized waste desulfurizing agent. After the stabilization process is completed, stabilized waste desulfurizing agent is obtained. The stabilized waste desulfurizing agent is cleaned up to prepare for the filling of the next batch of new desulfurizing agent.

2. The method for mild oxidative stabilization of waste desulfurizing agent according to claim 1, characterized in that: In step three, the airspeed is controlled at 114-190 h. -1 .

3. The method for mild oxidative stabilization of waste desulfurizing agent according to claim 1, characterized in that: In step three, air is introduced from the bottom of the storage tank and discharged from the top of the storage tank.

4. The method for mild oxidative stabilization of waste desulfurizing agent according to claim 1, characterized in that: In step three, air is introduced from the top of the storage tank and discharged from the bottom of the storage tank.

5. The method for mild oxidative stabilization of waste desulfurizing agent according to claim 1, characterized in that: In step four, the temperature at at least one location inside the storage tank is monitored in real time.

6. The method for mild oxidative stabilization of waste desulfurizing agent according to claim 1, characterized in that: In step five, when the monitored temperature reaches its peak and begins to drop to near the initial temperature, the slow oxidation reaction is considered to be basically complete.

7. The method for mild oxidative stabilization of waste desulfurizing agent according to claim 1, characterized in that: The exhaust gas discharged from the storage tank will be passed into a carbon canister for treatment.

8. The apparatus for a mild oxidative stabilization method for waste desulfurizing agent according to any one of claims 1-7, characterized in that, include: Storage tank: Used to contain waste desulfurizing agent and to achieve gas flow direction of top inlet and bottom outlet or bottom inlet and top outlet; The air supply and control unit, including an air compressor, a pressure reducing valve, and a ball valve, is used to control the air velocity between 100 and 300 h⁻¹. -1 ; A rotor flow meter, connected downstream of the ball valve, is used to monitor and provide feedback on the air velocity; Temperature monitoring unit: installed outside or inside the storage tank, used to monitor the oxidation reaction temperature inside the storage tank; Activated carbon canister: Located at the gas outlet of the storage tank, it is filled with activated carbon to adsorb sulfur-containing gases in the exhaust gas.

9. The apparatus for a mild oxidative stabilization method for waste desulfurizing agent according to claim 8, characterized in that: The temperature monitoring unit is an infrared thermometer.

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