Method for using coking agent in incineration device

Abstract

The present invention discloses a method for using a coke flux in an incineration device. The method comprises the following steps: S1, collecting coke in the incineration device, and analyzing the precursor components of the coke; screening and obtaining the corresponding coke flux according to the precursor components in combination with a combustion test; the coke flux includes an alkaline metal oxide; S2, simulating an incineration experiment of the coke flux and the coke in an oxygen-permeable environment, and determining the mass ratio of the coke to the coke flux; S3, adding the coke flux to the incineration device containing the coke for coking treatment according to the mass ratio. The present invention can quantify the usage mode, usage amount, and usage conditions of the coke flux, so as to achieve the optimal usage amount and feeding method of the coke flux while ensuring the decoking effect, saving the usage amount of the coke flux, improving the usage efficiency of the coke flux, ensuring its decoking effect, and protecting the refractory materials of the equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial hazardous waste treatment, and in particular to a method for using a coking agent in an incineration device. Background Art

[0002] The incinerator temperature for the incineration of existing hazardous industrial waste is required to be ≥1100°C. Some materials contain precursors that form coke. When coke is formed under high temperature conditions, it blocks the furnace wall, flue, and boiler heat exchange tubes, seriously hindering the long-term stable operation of the incineration system.

[0003] Existing online decoking technologies mostly use chemical inhibition or reaction micro-explosion, raising the melting point and other methods to prevent coking. The existing public technologies do not specifically quantify the details such as usage method, usage amount, and operating conditions. There are often problems such as high cost and low efficiency of chemical use, damage to equipment refractory materials, and shortened practical life of refractory materials. Summary of the Invention

[0004] To overcome the drawback of prior art techniques for treating coke deposits using a coke fluxing agent, which lacks specific quantification of its usage, dosage, and operating conditions, the present invention provides a method for using a coke fluxing agent in an incineration device. This method quantifies the usage, dosage, and operating conditions of the coke fluxing agent, ensuring a decoking effect while achieving the optimal dosage and feeding method. This approach conserves the amount of coke fluxing agent used, improves its efficiency, ensures its decoking effect, and protects the refractory materials of the equipment.

[0005] In order to solve the above technical problems, this application provides the following technical solutions:

[0006] The present invention provides a method for using a coke melting agent in an incineration device, the method comprising the following steps:

[0007] S1. Collecting coke in an incineration device and analyzing precursor components of the coke; screening and obtaining a corresponding coke melting agent based on the precursor components and a combustion test; the coke melting agent includes an alkaline metal oxide;

[0008] S2. Simulating an incineration experiment of the coke melting agent and the coke product in an oxygen-permeable environment to determine a mass ratio of the coke product to the coke melting agent;

[0009] S3. Add the coking agent to the incineration device containing the coke material according to the mass ratio to perform coking treatment.

[0010] In the present invention, the coke may be referred to as a coke mass.

[0011] In step S1 of the present invention, the incineration device can be used for incineration of hazardous waste, and it can be a conventional incinerator in the art.

[0012] The incinerator generally includes a secondary combustion chamber and a storage chamber.

[0013] In some embodiments, in step S1, the location where the coke is collected includes the bottom inclined plate of the secondary combustion chamber of the incineration device, the large elbow at the top of the secondary combustion chamber of the incineration device, the top of the chamber of the incineration device, or the bottom of the chamber of the incineration device.

[0014] In some embodiments, in step S1, the precursor component is one or more of silicate, aluminosilicate, sulfate and iron-containing compound; by confirming the common precursor components of different incoming sintered cokes, the corresponding coking agent is selected according to the common precursor components.

[0015] In some embodiments, in step S1, the analysis method includes apparent density analysis, electron scanning microscopy analysis, energy spectrum elemental composition analysis, X-ray diffraction analysis, thermogravimetric analysis, or differential scanning calorimetry analysis.

[0016] In one embodiment, the apparent density analysis shows that the average apparent density of the coke is 1.69 g / cm 3 .

[0017] In one embodiment, the electron scanning microscope analysis revealed that the coke deposits on each component of the incineration device all contained amorphous sintered materials at the microscopic level, and their microscopic morphologies were highly consistent.

[0018] In one embodiment, through the energy spectrum elemental composition analysis, it was found that the coke on each component in the incineration device contained O, Si, Al, S, Ca, Fe, Na elements and a small amount of Mg, K, Zn, Ba, Cu and other elements, and the elemental composition was obviously consistent.

[0019] In one embodiment, the X-ray diffraction analysis shows that the composition of the coke deposits on the various components in the incineration device is CaSiO3, NaAlSi3O8, CaFeSi2O6, etc., and the crystal phase structure thereof has a strong consistency.

[0020] In one embodiment, the thermogravimetric analysis shows that the coke deposits on each component in the incineration device contain substances that can be volatile at high temperatures, and the weight loss rate in the temperature range of room temperature to 1200°C is between 6-10%, which has a relatively consistent high-temperature weight loss rate.

[0021] In one embodiment, the differential scanning calorimetry analysis shows that the coke on each component in the incineration device has an endothermic phenomenon in the two temperature ranges of 500-700°C and 1100-1200°C, indicating that certain components in the coke melt and have a relatively consistent melting temperature range.

[0022] In some embodiments, in step S1, the combustion test includes the following process: burning different coke materials with each of the coke melting agents, and determining the coke melting agent to be used corresponding to each of the coke materials based on whether the coke materials and the coke melting agent are melted.

[0023] In some embodiments, in step S1, the alkaline metal oxide is one or more of sodium oxide, potassium oxide, and calcium oxide.

[0024] In step S2 of the present invention, those skilled in the art should understand that the incineration experiment is an experimental method for quantifying the amount of coke melting agent to be added.

[0025] In step S2 of the present invention, the mass ratio of the coke product to the coke melting agent refers to the optimal feeding ratio of the coke melting agent; it can be the optimal feeding ratio value or the optimal feeding ratio range.

[0026] In some embodiments, in step S2, the mass ratio of the coke material to the coke melting agent is 1:(0.5~2), that is, the amount of coke melting agent required to remove 1 kg of coke material is 0.5 kg to 2 kg.

[0027] In a specific embodiment, the mass ratio of the coke material to the coke melting agent is 1:(1.5-2).

[0028] In one embodiment, the mass ratio of the coke to the coke melting agent is 1:2.

[0029] In some embodiments, in step S2, the peroxygen environment has a peroxygen coefficient of 1.5 times or more.

[0030] In some embodiments, in step S3, the addition conditions of the coking agent meet one or both of the following conditions:

[0031] ① When the flue gas negative pressure in the incineration device reaches -125 Pa to -300 Pa, the coking agent is added;

[0032] ② When the accumulated amount of coking blockage in the flue of the incineration device is ≥2 tons, add the coking agent;

[0033] ③ The addition conditions of the coking agent are calculated based on the operating negative pressure and slag accumulation of the incineration device.

[0034] Among them, under the above-mentioned adding conditions, it is possible to avoid damage to equipment refractory materials due to premature addition of coking agent, and to avoid reducing coking efficiency and increasing the usage of coking agent due to late addition of coking agent.

[0035] In some embodiments, in step S3, the method of adding the coking agent includes using a dosing device.

[0036] In some embodiments, in step S3, the coking agent is added continuously rather than intermittently.

[0037] In one embodiment, a dosing device allows for continuous addition of the coke-melting agent, miniaturizing and precisely designing the hourly delivery rate of the dosing device, thereby achieving continuous and uniform contact and fusion between the coke-melting agent and the coked material. This adaptability allows for adaptability to the different coking conditions of hazardous waste incineration.

[0038] In some embodiments, in step S3, the temperature of the incineration device is 1100-1200°C.

[0039] In some embodiments, in step S3, the melting point of the mixture formed by the coking agent and the coke is less than 950°C; the melting point of the mixture is lower than the melting point of the coking agent and the melting point of the coke, thereby achieving the removal of the coke at the normal operating temperature of the incineration device.

[0040] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0041] The reagents and raw materials used in the present invention are commercially available.

[0042] This application includes at least one of the following beneficial technical effects:

[0043] 1. The method of use of the present invention can quantify the usage, amount, and operating conditions of the coke fluxing agent, thereby ensuring the decoking effect while achieving the optimal usage amount and feeding method of the coke fluxing agent, saving the amount of coke fluxing agent used, improving the efficiency of the coke fluxing agent, ensuring its decoking effect, and protecting the refractory materials of the equipment;

[0044] 2. By adopting the above technical solution, the amount of coke melting agent used is quantified. Compared with other methods, the method of the present invention can make the amount of coke melting agent used more precise, avoiding the problem of excessive addition of coke melting agent causing agent waste, or insufficient addition causing insufficient decoking effect;

[0045] 3. By adopting the above technical solution, a mixture of coke flux and coke material is formed after incineration in a certain proportion. The coke material reacts with the coke flux to form a low-melting-point eutectic of metal salts and oxides. The melting point of the eutectic mixture is lower than the general operating temperature of the hazardous waste incinerator, enabling the incinerator to melt and remove coke material in the furnace and flue at the normal operating temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a diagram of the product after the coke and the coke melting agent in Example 1.3 are melted.

[0047] Figure 2 This is a diagram of the product after the coke and the coke melting agent in Example 1.4 are melted.

[0048] Figure 3 This is a diagram of the product after the coke and the coke melting agent in Example 1.5 are melted. DETAILED DESCRIPTION

[0049] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0050] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0051] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0052] Herein, “comprising,” “including,” “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of,” for example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to have been disclosed herein.

[0053] Throughout this document, all features, such as values, amounts, contents, and concentrations, specified in numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to encompass and specifically disclose all possible subranges and individual values ​​within those ranges (including integers and fractions).

[0054] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0055] Herein, when describing embodiments or examples, it should be understood that they are not intended to limit the present invention to these embodiments or examples. On the contrary, all alternatives, modifications and equivalents of the methods and materials described herein are encompassed within the scope defined by the claims.

[0056] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0057] The present invention will be described below by way of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents, and materials used in the examples are, unless otherwise stated, conventional methods, reagents, and materials in the art. The starting compounds in the examples can all be purchased from commercial sources.

[0058] Example 1

[0059] This embodiment discloses a method for using a coke-melting agent in an incineration device, which method includes the following steps:

[0060] S1. Collecting coke in an incineration device and analyzing precursor components of the coke; screening and obtaining a corresponding coke melting agent based on the precursor components and in combination with a combustion test; the coke melting agent includes an alkaline metal oxide;

[0061] S2. Simulate the combustion experiment of the coke melting agent and the coke product in an oxygen-permeable environment to determine the mass ratio of the coke product to the coke melting agent;

[0062] S3. Add the coking agent to the incineration device containing the coke material according to the mass ratio to carry out coking treatment.

[0063] In step S1, the locations where the coke is collected include the bottom inclined plate of the secondary combustion chamber of the incineration device, the large elbow at the top of the secondary combustion chamber of the incineration device, the top of the chamber of the incineration device, and the bottom of the chamber of the incineration device.

[0064] In step S1, the precursor components include silicate, aluminosilicate, sulfate and iron-containing compound;

[0065] In step S1, the analysis methods include apparent density analysis, electron scanning microscopy analysis, energy spectrum elemental composition analysis, X-ray diffraction analysis, thermogravimetric analysis and differential scanning calorimetry analysis;

[0066] In step S1, the combustion test includes the following process: burning different coke materials with various coke melting agents, and determining the coke melting agent to be used for each coke material according to whether the coke materials and the coke melting agent melt;

[0067] In step S1, the alkaline metal oxide is a mixture of sodium oxide, potassium oxide and calcium oxide.

[0068] In step S2, the mass ratio of the coke material to the coke melting agent is 1:(0.5~2).

[0069] In step S2, the peroxygen environment has a peroxygen coefficient of 1.5 times.

[0070] In step S3, the operating conditions for adding the coking agent are calculated based on the operating negative pressure of the incinerator and the amount of slag accumulation. Table 1 shows different blockage conditions of the flue in the incinerator.

[0071] Table 1

[0072]

[0073] In Table 1, the flue blockage rate is the percentage of the flue blockage area by coke to the flue area. All calculated data for flue blockage rates of 0-40% are listed here for viewing the changes in negative pressure and coke accumulation under different blockage areas. Combined with the mass ratio of coke to coke flux in the above steps S1 and S2, the amount of coke flux used is calculated.

[0074] According to theoretical calculations, when the flue gas negative pressure in the incinerator reaches -125 Pa ~ -300 Pa, and the accumulated amount of coking blockage in the flue of the incinerator is ≥2 tons, a 180 ~ 450mm coke layer is retained. Adding coking agent under this operating condition can effectively avoid damage to the refractory materials of the incinerator and other non-coked parts of the equipment due to premature addition of coking agent, and reduce the coking efficiency and increase the use of coking agent due to late addition of coking agent.

[0075] Specifically, the flue design negative pressure is -100Pa. When the blockage is 10%, the negative pressure deteriorates to -125.67Pa. At this time, the coke layer thickness is 180mm and the weight is 2.1t. Under this working condition, adding a coke melting agent can protect the flue refractory from damage.

[0076] When the negative pressure exceeds -300Pa and the coking agent is added, the slag layer has exceeded 450mm and the flue gas flow rate is too fast due to blockage, which is greater than 27m / s. At this time, the economic flow rate has been exceeded (the economic flow rate of industrial gas is 15-25m / s). The flow rate of the flue gas system is too large, the resistance increases, the fan energy consumption increases, and the effective coverage rate of the coking agent after it is injected into the furnace is very low. Most of the coking agent is carried away by the flue gas, which increases the use of the coking agent.

[0077] Specifically, the flue is designed to have a negative pressure of -100Pa. When the blockage is 25%, the negative pressure deteriorates to -312.92Pa. At this time, the coke layer is 450mm thick and weighs 4.8t. However, the flue gas flow rate has reached 27m / s, exceeding the normal economic flow rate of the flue gas duct. If the negative pressure continues to deteriorate, and the flue gas flow rate is faster, the injected coke melting agent will be carried by the flue gas, and the effective coverage rate will be reduced.

[0078] In step S3, a coke-melting agent is continuously added via a dosing device and delivered to the coke-forming area. The coke-melting agent utilizes its inherent physical property, namely its melting point, to form a mixture with the incinerated coke. This mixture is a low-melting-point eutectic of sodium salts and oxides, with a melting point of less than 950°C. Hazardous waste incinerators generally require an operating temperature of 1100-1200°C. This allows the incinerator to melt and remove coke from locations such as the furnace and flue at normal operating temperatures.

[0079] Examples 1.1 and 1.2

[0080] This embodiment tests the melting of coke in the incinerator with or without a coking agent.

[0081] Example 1.1 Before step S3, a coke sample in the incinerator is taken and the coke is completely mixed after adding the reagent and then subjected to a melting test:

[0082] After adding the coke sample, the completely mixed coke begins to change at 850℃, the upper part can flow at 900℃, it becomes spherical at 940℃, and completely melts at 960-1000℃;

[0083] Example 1.2 Before step S3, a sample of coke in the incinerator without adding any chemicals is taken for melting test:

[0084] The coke sample without adding chemicals showed no change at 860℃, no change at 920℃, and no change at 940℃-1000℃. The upper part began to change and flow at 1060℃, became hemispherical at 1150℃, and completely melted at 1250℃.

[0085] Experimental data shows that the melting temperature of the coke sample is relatively high, exceeding 1200°C for complete melting. However, the use of a coke melting agent can reduce the melting temperature of the reaction product to less than 950°C, meaning that it can completely melt below 1100°C. At the operating temperature of the incinerator system, 1100-1200°C, the coke melting agent can be used to lower the melting point of the coke, causing it to melt.

[0086] Examples 1.3 to 1.5

[0087] This group of examples discloses experiments with different addition amounts of coking agent.

[0088] Example 1.3

[0089] Take 10g of the coke sample in the incinerator, heat it to 650℃ (furnace display temperature) in a simulated atmosphere furnace with peroxygen environment, and start adding the coke melting agent. At this time, the coke is in a red-hot state and has not yet melted. After adding the coke melting agent, the coke melting agent quickly decomposes and boils on the surface of the coke. After a few minutes, the coke melting agent is added again. Bubbles continue to appear on the surface of the coke, and the surface of the coke is visually molten. With the continuous addition of the coke melting agent, the surface of the coke keeps bubbling and boiling. At the same time, the temperature is controlled at 900-950℃. During this period, except for the added part, the other parts of the coke have not melted. After 5g of the coke melting agent (the mass ratio of coke to coke melting agent is 1:0.5), the addition is stopped. The reaction lasts for about 30 minutes. The reaction is more violent and its size also changes greatly. The length and height are reduced by about 0.5 cm.

[0090] The coke treated in this experiment was analyzed using a field emission environmental scanning electron microscope (FEI, Quanta 450 FEG | Quanta 450 FEG). Figure 1 . Figure 1 This is the product image after the coke and coke flux are melted in Experiment 1.3. The coke is not completely melted during combustion, only part of it flows and melts. After the mixture is cooled, the electron microscope scanning structure shows a loose state.

[0091] Example 1.4

[0092] Take 10g of the coke sample in the incinerator, heat it to 650℃ (furnace display temperature) in a simulated atmosphere furnace with peroxygen environment, and start adding chemicals. After adding chemicals, only the coke flux can be seen melting, decomposing and adhering to it, and the coke does not change. There is still no change when the coke flux is increased to 10g (the mass ratio of coke to coke flux is 1:1).

[0093] When the temperature is raised to 900-950℃ (furnace apparent temperature), bubbling, boiling and softening appear in the upper and middle parts of the coke, but the bottom is hemispherical, achieving partial flow and melting.

[0094] Using the electron microscopy analysis method as in Experiment 1.3, we obtain Figure 2 . Figure 2 This is the product image after the coke and coke flux are melted in Experiment 1.4. The burned part of the coke appears to be flowing and molten. After the mixture is cooled, the electron microscope scanning structure shows a crystalline block.

[0095] Example 1.5

[0096] Take 10g of the coke sample in the incinerator, heat it to 650℃ (furnace apparent temperature) in a simulated atmosphere furnace with peroxygen environment, and start adding the agent. The amount of coke melting agent is increased to 20g (the mass ratio of coke to coke melting agent is 1:2).

[0097] The temperature was controlled at 900-950℃. After 5 minutes, the surface of the coke began to boil and melt. Compared with Experiment 1.3, the softening rate of the reaction was faster, and there was bubbling flow over a large area. The corroded part first became fluid, and after 1000℃, it was completely fluid.

[0098] Using the electron microscopy analysis method as in Experiment 1.3, we obtain Figure 3 . Figure 3 This is the product image after the coke and coke flux are melted in Experiment 1.5. The coke is completely burned and presents a flowing and molten state. After the mixture is cooled, the electron microscope scanning structure shows obvious crystal phase and large block growth.

[0099] From the above experimental phenomena, we can know that:

[0100] (1) Above 850°C, the coking agent begins to decompose and cover the surface of the coke. Due to the different components of the coke, the reaction rate between the coke and the coking agent is inconsistent;

[0101] (2) In the temperature range of 900-950℃, the ratio of coke to coke flux is 1:(0.5-2). The molten coke flux can react with the coke to form a new mixture that lowers the melting point of the coke. At 1000℃, the coke is in a completely fluid liquid state.

[0102] The above is a non-limiting description of the present invention through examples according to the preferred production form of the present invention, but it should be understood that within the scope defined by the appended claims, those skilled in the art may make changes and / or modifications without departing from the relevant scope of protection.

Claims

1. A method for using a coking agent in an incineration device, characterized in that: The method of use comprises the following steps: S1. Collecting coke in an incineration device and analyzing precursor components of the coke; screening and obtaining a corresponding coke melting agent based on the precursor components and a combustion test; the coke melting agent includes an alkaline metal oxide; S2. Simulating an incineration experiment of the coke melting agent and the coke product in an oxygen-permeable environment to determine a mass ratio of the coke product to the coke melting agent; S3, adding the coking agent to an incineration device containing the coke material according to the mass ratio to perform coking treatment; The coke reacts with the coke melting agent to form a low melting point metal salt and oxide eutectic, and the melting point of the eutectic is lower than the operating temperature of the incineration device.

2. The method of use according to claim 1, wherein: Step S1 satisfies one or more of the following conditions: ① The locations where the coke is collected include the inclined plate at the bottom of the secondary combustion chamber of the incinerator, the large elbow at the top of the secondary combustion chamber of the incinerator, the top of the chamber of the incinerator, or the bottom of the chamber of the incinerator; ② The precursor component is one or more of silicate, aluminosilicate, sulfate and iron-containing compound; ③ The analysis method includes apparent density analysis, electron scanning microscopy analysis, energy spectrum elemental composition analysis, X-ray diffraction analysis, thermogravimetric analysis or differential scanning calorimetry analysis; ④ The combustion test includes the following process: burning different coke materials with each of the coke melting agents, and determining the coke melting agent to be used corresponding to each of the coke materials based on whether the coke materials and the coke melting agent are melted.

3. The method of use according to claim 1, wherein: In step S1, the alkaline metal oxide is one or more of sodium oxide, potassium oxide and calcium oxide.

4. The method of use according to claim 1, wherein: In step S2, the mass ratio of the coke material to the coke melting agent is 1:(0.5-2).

5. The method of use according to claim 4, wherein: The mass ratio of the coke material to the coke melting agent is 1:(1.5~2).

6. The method of use according to claim 1, wherein: In step S2, the peroxygen environment has a peroxygen coefficient of 1.5 times or more.

7. The method of use according to claim 1, wherein: In step S3, the addition conditions of the coking agent meet one or more of the following conditions: ① When the flue gas negative pressure in the incineration device reaches -125 Pa to -300 Pa, the coking agent is added; ② When the accumulated amount of coking blockage in the flue of the incineration device is ≥2 tons, add the coking agent; ③ The addition conditions of the coking agent are calculated based on the operating negative pressure and slag accumulation of the incineration device.

8. The method of use according to claim 1, wherein: In step S3, the method of adding the coking agent satisfies one or both of the following conditions: ① The method of adding the coking agent includes using a dosing device; ② The coking agent is added in a continuous manner.

9. The method of use according to claim 1, wherein: In step S3, the temperature of the incineration device is 1100-1200°C.

10. The method of use according to claim 1, wherein: In step S3, the melting point of the mixture formed by the coking agent and the coke is less than 950°C.

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