Method for using coke melting agent in incineration device

Abstract

The invention discloses a using method of a coke melting agent in an incineration device. The method comprises the following steps: S1, collecting coking materials in an incineration device, and analyzing precursor components of the coking materials; according to the components of the precursor, a combustion test is combined, and a corresponding coke melting agent is obtained through screening; the coke melting agent comprises alkaline metal oxide; s2, simulating an incineration experiment of a coke melting agent and a coking material in a peroxy environment, and determining a mass ratio of the coking material to the coke melting agent; and S3, according to the mass ratio, the coke melting agent is added into an incineration device containing the coking matter for coke melting treatment. The use mode, the use amount and the use working condition of the coke melting agent can be quantified, so that the optimal use amount and the optimal feeding mode of the coke melting agent are realized while the decoking effect is ensured, the use amount of the coke melting agent is saved, the use efficiency of the coke melting agent is improved, the decoking effect of the coke melting agent is ensured, and meanwhile, refractory materials of equipment are protected.

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 coke melting agent in an incineration device. Background Art

[0002] When disposing of existing industrial hazardous waste by incineration, it is required that the temperature of the incinerator is ≥1100°C. Some materials contain precursors for coke formation, which form coke deposits at high temperatures and block the furnace wall, flue, and boiler heat exchange tubes, seriously hindering the long-term stable operation of the incineration system.

[0003] Existing online coke removal technologies mostly use methods such as chemical agent inhibition, reaction microexplosion, and melting point elevation to prevent coking. In the existing publicly disclosed technologies, details such as the usage method, usage amount, and usage conditions are not specifically quantified, often resulting in problems such as high chemical agent usage costs, low usage efficiency, damage to equipment refractories, and shortening of the practical life of refractories. Summary of the Invention

[0004] In order to overcome the defect that the existing technology does not specifically quantify the usage method, usage amount, and usage conditions in the process of using a coke melting agent to treat coke deposits, the present invention provides a method for using a coke melting agent in an incineration device. The usage method of the present invention can quantify the usage method, usage amount, and usage conditions of the coke melting agent to ensure the best usage amount and feeding method of the coke melting agent while ensuring the coke removal effect, saving the usage amount of the coke melting agent, improving the usage efficiency of the coke melting agent, ensuring its coke removal effect, and at the same time protecting the equipment refractories.

[0005] In order to solve the above technical problems, the present application provides the following technical solutions: The present invention provides a method for using a coke melting agent in an incineration device, and the usage method includes the following steps: S1. Collect coke deposits in the incineration device and analyze the precursor components of the coke deposits; according to the precursor components, combined with combustion tests, screen to obtain the corresponding coke melting agent; the coke melting agent includes basic metal oxides; S2. In a hyperoxic environment, simulate the incineration experiment of the coke melting agent and the coke deposits to determine the mass ratio of the coke deposits to the coke melting agent; S3. Add the coke melting agent to the incineration device containing the coke deposits according to the mass ratio for coke melting treatment.

[0006] In the present invention, the coke deposits can be referred to as coke lumps.

[0007] In step S1 of the present invention, the incineration device can be used for hazardous waste incineration and can be a conventional incinerator in the art.

[0008] Among them, the incinerator generally includes a secondary combustion chamber and a storage chamber.

[0009] In some embodiments, in step S1, collecting the position of the coking product includes the inclined plate part at the bottom of the secondary combustion chamber of the incineration device, the large elbow part 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.

[0010] In some embodiments, in step S1, the precursor components are one or more of silicate, aluminosilicate, sulfate, and iron-containing compounds; by confirming the common precursor components of the coking products from different incoming materials, corresponding coke melting agents are selected according to the common precursor components.

[0011] In some embodiments, in step S1, the analysis methods include apparent density analysis, electron scanning microscope analysis, energy spectrum elemental composition analysis, X-ray diffraction analysis, thermogravimetric analysis, or differential scanning calorimetry analysis.

[0012] In a certain embodiment, through the apparent density analysis, the average apparent density of the coking product is obtained as: 1.69 g / cm 3 。

[0013] In a certain embodiment, through the electron scanning microscope analysis, it is obtained that amorphous sintered products exist microscopically on each component in the incineration device, and their microscopic morphologies have strong consistency.

[0014] In a certain embodiment, through the energy spectrum elemental composition analysis, it is obtained that the coking products on each component in the incineration device all contain elements such as O, Si, Al, S, Ca, Fe, Na, and a small amount of elements such as Mg, K, Zn, Ba, Cu, etc., and their elemental compositions have obvious consistency.

[0015] In a certain embodiment, through the X-ray diffraction analysis, it is obtained that the compositions of the coking products on each component in the incineration device are CaSiO 3 、NaAlSi 3 O 8 、CaFeSi 2 O 6 etc., and their crystal phase structures have strong consistency.

[0016] In a certain embodiment, through the thermogravimetric analysis, thermally volatile substances exist in the coking products on each component in the incineration device at high temperatures, and the weight loss rates are all between 6 - 10% in the temperature range from room temperature to 1200 °C, and they have relatively consistent high-temperature weight loss rates.

[0017] In one embodiment, through the differential scanning calorimetry, endothermic phenomena occur in the coke deposits on the components in the incineration device in two temperature ranges of 500 - 700 °C and 1100 - 1200 °C, indicating that some components in the coke deposits melt, and it has a relatively consistent melting temperature range.

[0018] In some embodiments, in step S1, the combustion test includes the following process: burning different coke deposits with each of the coke melting agents, and determining the corresponding coke melting agent for each coke deposit according to whether the coke deposit and the coke melting agent melt.

[0019] In some embodiments, in step S1, the alkaline metal oxide is one or more of sodium oxide, potassium oxide, and calcium oxide.

[0020] 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 addition amount of the coke melting agent.

[0021] In step S2 of the present invention, the mass ratio of the coke deposit 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.

[0022] In some embodiments, in step S2, the mass ratio of the coke deposit to the coke melting agent is 1:(0.5 - 2), that is, the amount of the coke melting agent required to remove 1 kg of the coke deposit is 0.5 kg - 2 kg.

[0023] In a specific embodiment, the mass ratio of the coke deposit to the coke melting agent is 1:(1.5 - 2).

[0024] In one embodiment, the mass ratio of the coke deposit to the coke melting agent is 1:2.

[0025] In some embodiments, in step S2, the over-oxygen environment is an over-oxygen coefficient of more than 1.5 times.

[0026] In some embodiments, in step S3, the addition conditions of the coke melting agent satisfy one or both of the following conditions: ① When the flue gas negative pressure in the incineration device reaches -125 Pa to -300 Pa, add the coke melting agent; ② When the accumulated amount of coke deposit blockage in the flue of the incineration device ≥ 2 tons, add the coke melting agent; ③ The addition conditions of the coke melting agent are based on the calculated data of the operating negative pressure and slag accumulation amount of the incineration device.

[0027] 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.

[0028] In some embodiments, in step S3, the method of adding the coking agent includes using a dosing device.

[0029] In some embodiments, in step S3, the coking agent is added continuously rather than intermittently.

[0030] In one embodiment, the coking agent is continuously added through the dosing device, so that the hourly delivery volume of the dosing device can be miniaturized and precise, and the coking agent and the coke can be continuously and evenly contacted and fused. It is adaptable to the incineration and coking conditions of different hazardous waste materials.

[0031] In some embodiments, in step S3, the temperature of the incineration device is 1100-1200°C.

[0032] 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 will be lower than the melting points of the coking agent and the coke, thereby achieving the removal of the coke at the normal operating temperature of the incineration device.

[0033] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0034] The reagents and raw materials used in the present invention are commercially available.

[0035] The present application includes at least one of the following beneficial technical effects: 1. The method of use of the present invention can quantify the use mode, amount and working conditions of the coking agent, so as to achieve the optimal amount and feeding mode of the coking agent while ensuring the decoking effect, save the amount of the coking agent, improve the efficiency of the coking agent, ensure the decoking effect, and protect the refractory materials of the equipment; 2. By adopting the above technical solution, the amount of coking agent used is quantified; compared with other methods of use, the method of the present invention can make the amount of coking agent used more accurate, avoiding the problem of excessive addition of coking agent causing agent waste, or insufficient addition causing insufficient decoking effect; 3. By adopting the above technical solution, a mixture is formed after the coking agent and the coke material are burned at a certain ratio. The coke material reacts with the coking agent to form a low melting point metal salt and oxide eutectic. The melting point of the low eutectic mixture is lower than the general operating temperature required by the hazardous waste incinerator, so that the coke material in the furnace and flue and other locations can be melted and removed at the daily operating temperature of the incinerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is the diagram of the product after the coking product and the coke flux in Example 1.3 are melted.

[0037] Figure 2 It is the diagram of the product after the coking product and the coke flux in Example 1.4 are melted.

[0038] Figure 3 It is the diagram of the product after the coking product and the coke flux in Example 1.5 are melted. Detailed implementation manners

[0039] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples. For the experimental methods without specific conditions in the following examples, they are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0040] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meanings understood by those skilled in the art for the present invention. In case of conflict, the definitions in this specification shall prevail.

[0041] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not limit the scope of the present invention in any way, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0042] In this article, terms such as "comprising", "including", "containing" and similar terms cover the meanings of "substantially consisting of..." and "consisting of...". For example, when it is disclosed herein that "A comprises B and C", it should be considered that "A substantially consists of B and C" and "A consists of B and C" have been disclosed herein.

[0043] In this article, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the ranges (including integers and fractions).

[0044] In this article, unless otherwise specified, the percentage refers to the mass percentage and the ratio refers to the mass ratio.

[0045] In this article, when describing the implementation schemes or examples, it should be understood that they are not used to limit the present invention to these implementation schemes or examples. On the contrary, all alternatives, improvements and equivalents of the methods and materials described in the present invention can be covered within the scope defined by the claims.

[0046] In this text, for the sake of concise description, not all possible combinations of all technical features in each implementation or embodiment are described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation or embodiment can be combined arbitrarily, and all possible combinations should be considered as the scope described in this specification.

[0047] The present invention will be elaborated below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and not intended to limit the scope of the present invention. The methods, reagents, and materials used in the embodiments are conventional methods, reagents, and materials in the art unless otherwise specified. The starting compounds in the embodiments can all be obtained through commercial channels.

[0048] Example 1 This example discloses a method for using a coke melting agent in an incineration device. The method includes the following steps: S1. Collect coke deposits in the incineration device and analyze the precursor components of the coke deposits; according to the precursor components and in combination with combustion tests, screen out the corresponding coke melting agent; the coke melting agent includes basic metal oxides. S2. Under a hyperoxic environment, simulate the incineration experiment of the coke melting agent and the coke deposits to determine the mass ratio of the coke deposits to the coke melting agent. S3. Add the coke melting agent to the incineration device containing the coke deposits according to the mass ratio for coke melting treatment.

[0049] In step S1, the positions for collecting the coke deposits include the inclined plate part at the bottom of the secondary combustion chamber of the incineration device, the large elbow part 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.

[0050] In step S1, the precursor components include silicate, aluminosilicate, sulfate, and iron-containing compounds. In step S1, the analysis methods include apparent density analysis, electron scanning microscope analysis, energy spectrum elemental composition analysis, X-ray diffraction analysis, thermogravimetric analysis, and differential scanning calorimetry analysis. In step S1, the combustion test includes the following process: Burn different coke deposits with each coke melting agent, and determine the coke melting agent corresponding to each coke deposit according to whether the coke deposits and the coke melting agent are melted. In step S1, the basic metal oxides are a mixture of sodium oxide, potassium oxide, and calcium oxide.

[0051] In step S2, the mass ratio of the coke deposits to the coke melting agent is 1:(0.5 - 2).

[0052] In step S2, the hyperoxic environment is a hyperoxic coefficient of 1.5 times.

[0053] In step S3, the operating conditions for adding the coke melting agent are the calculated data based on the negative pressure during the operation of the incinerator and the amount of slag accumulation. Table 1 shows different blockage situations of the flue in the incineration device.

[0054] Table 1

[0055] In Table 1, the flue blockage rate is the percentage of the area blocked by the coke deposits in the flue area. All the calculated data with the flue blockage rate ranging from 0 to 40% are listed here for viewing the variation values of the negative pressure and the accumulation amount of coke deposits under different blockage areas. Combining the mass ratio of the coke deposits to the coke melting agent in the aforementioned steps S1 and S2, the dosage of the coke melting agent is calculated.

[0056] According to theoretical calculations, when the negative pressure of the flue gas in the incinerator reaches -125 Pa to -300 Pa, and at the same time, the accumulated amount of coke blockage in the flue of the incinerator is ≥ 2 tons, a coke layer of 180 - 450 mm is retained. Adding the coke melting agent under these operating conditions can effectively avoid the damage to the refractories of the incinerator and the equipment in other non-coked parts due to the premature addition of the coke melting agent, as well as the reduction of the coke melting efficiency and the increase in the usage amount of the coke melting agent due to the late addition of the coke melting agent.

[0057] Specifically, the designed negative pressure of the flue is -100 Pa. When it is blocked by 10%, the negative pressure deteriorates to -125.67 Pa. At this time, the coke layer thickness is 180 mm and the weight is 2.1 t. Adding the coke melting agent under these operating conditions can protect the flue refractories from damage; When the negative pressure exceeds -300 Pa and then the coke melting agent is added, at this time, since the slag accumulation layer has exceeded 450 mm, and due to the too-fast flow rate of the blocked flue gas > 27 m / s, which has exceeded the economic flow rate at this time (the economic flow rate of industrial gases is 15 - 25 m / s), the flow rate of the flue gas system is too large, the resistance increases, the energy consumption of the fan rises, and the effective coverage rate of the coke melting agent injected into the furnace is very low. Most of the coke melting agent is carried away by the flue gas, increasing the usage amount of the coke melting agent.

[0058] Specifically, the designed negative pressure of the flue is -100 Pa. When it is blocked by 25%, the negative pressure deteriorates to -312.92 Pa. At this time, the coke layer thickness is 450 mm and the weight is 4.8 t. However, at this time, the flow rate of the flue gas has reached 27 m / s, exceeding the economic flow rate of the normal flue gas pipeline. If the negative pressure continues to deteriorate, it will be higher and the flow rate of the flue gas will be faster, resulting in the coke melting agent being carried by the flue gas and the effective coverage rate decreasing.

[0059] In step S3, the coke melting agent is continuously added through a dosing device and transported to the coking site. The coke melting agent forms a mixture with the products after the coking materials are burned by utilizing the inherent physical property of the substance, namely the melting point. This mixture is a eutectic melt of low-melting sodium salts and oxides, with a melting point < 950°C, while the hazardous waste incinerator generally requires an operating temperature of 1100 - 1200°C. Thus, under the daily operating conditions of the incinerator, the coking materials at positions such as inside the furnace and in the flue are melted and removed.

[0060] Examples 1.1 and 1.2 In this example, a melting test of the coking materials with and without the coke melting agent inside the incinerator was conducted.

[0061] Before step S3 in Example 1.1, a melting test was carried out on the coking materials obtained by completely mixing the coking material samples inside the incinerator after adding the medicine: The coking materials obtained by completely mixing the coking material samples after adding the medicine started to change at 850°C, the upper part could flow at 900°C, became spherical at 940°C, and were completely melted at 960 - 1000°C; Before step S3 in Example 1.2, a melting test was carried out on the coking materials of the coking material samples inside the incinerator without adding the medicine: The coking materials of the coking material samples without adding the medicine showed no change at 860°C, no change at 920°C, no change from 940°C to 1000°C, the upper part started to change and flow at 1060°C, became hemispherical at 1150°C, and were completely melted at 1250°C.

[0062] From the experimental data, it can be seen that the melting temperature of the coking material samples is relatively high, and the complete melting temperature exceeds 1200°C; while after using the coke melting agent, the melting temperature of the reaction products can be reduced to < 950°C, that is, they can be completely melted below 1100°C. At the operating temperature of 1100 - 1200°C of the incinerator system, the coke melting agent can be used to lower the melting point of the coking materials and melt the coking materials.

[0063] Examples 1.3 - 1.5 This group of examples discloses experiments on different addition amounts of the coke melting agent.

[0064] Example 1.3 Take 10 g of the coking sample in the incinerator. When heated to 650 °C (furnace display temperature) in an oxygen-rich environment in a simulated atmosphere furnace, start adding the coke-melting agent. At this time, the coking sample shows a red-hot state and does not reach the melting point. After adding the coke-melting agent, the coke-melting agent decomposes rapidly, showing a boiling state on the surface of the coking sample. After a few minutes, add the coke-melting agent again. Bubbles continuously appear on the surface of the coking sample. Visually, the surface of the coking sample has reached the melting state. With the continuous addition of the coke-melting agent, bubbles continuously boil on the surface of the coking sample. At the same time, the temperature is controlled at 900 - 950 °C. During this period, except for the part where the agent is added, other parts of the coking sample have not melted. Stop adding the coke-melting agent when 5 g is added (the mass ratio of the coking sample to the coke-melting agent is 1:0.5). The reaction lasts for about 30 minutes and is relatively intense. Its size also changes significantly, with the length and height reduced by about 0.5 cm.

[0065] The coking sample after the treatment in this experiment was analyzed using a field emission environmental scanning electron microscope (FEI Company, Quanta 450 FEG | Quanta 450 FEG) to obtain Figure 1 . Figure 1 It is the product diagram of the coking sample and the coke-melting agent after melting in Experiment 1.3. The coking sample did not completely reach the melting state during combustion, only partially flowed and melted. The electron microscope scanning structure of the mixture was loose after cooling.

[0066] Example 1.4 Take 10 g of the coking sample in the incinerator. When heated to 650 °C (furnace display temperature) in an oxygen-rich environment in a simulated atmosphere furnace, start adding the agent. After adding the agent, only the melting and decomposition of the coke-melting agent adhering to it can be seen, and the coking sample shows no change. When the amount of the coke-melting agent is increased to 10 g (the mass ratio of the coking sample to the coke-melting agent is 1:1), there is still no change.

[0067] When the temperature is raised to 900 - 950 °C (furnace display temperature), bubbles, boiling, and softening occur in the upper and middle parts of the coking sample, but the bottom is hemispherical, achieving partial flow and melting.

[0068] Using the electron microscope analysis method as in Experiment 1.3, obtain Figure 2 . Figure 2 It is the product diagram of the coking sample and the coke-melting agent after melting in Experiment 1.4. The burning part of the coking sample shows a flowing and melting state. The electron microscope scanning structure of the mixture is crystalline and massive after cooling.

[0069] Example 1.5 Take 10 g of the coking sample in the incinerator. When heated to 650 °C (furnace display temperature) in an oxygen-rich environment in a simulated atmosphere furnace, start adding the agent, and increase the amount of the coke-melting agent to 20 g (the mass ratio of the coking sample to the coke-melting agent is 1:2).

[0070] 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 a large area of ​​bubbling flow. The corroded part first became fluid, and it was completely fluid after 1000℃.

[0071] Using the electron microscopy analysis method as in Experiment 1.3, we obtain Figure 3 . Figure 3 This is the product picture 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.

[0072] From the above experimental phenomena, we can know that: (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 coking agent and the coking agent is inconsistent; (2) In the temperature range of 900-950℃, the ratio of coke to coke melting agent is 1:(0.5-2). The molten coke melting agent can react with the coke to form a new mixture to lower the melting point of the coke, and it is completely liquid at 1000℃.

[0073] The above is a non-restrictive 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 attached 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 in combination with a combustion test; the coke melting agent includes an alkaline metal oxide; S2. In an oxygen-permeable environment, simulating a combustion experiment of the coking agent and the coked material, and determining a mass ratio of the coked material to the coking agent; S3. According to the mass ratio, the coking agent is added into the incineration device containing the coke to perform coking treatment.

2. The method of use according to claim 1, characterized in that: 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 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; 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 element 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, characterized in that: 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, characterized in that: In step S2, the mass ratio of the coke to the coke melting agent is 1:(0.5-2).

5. The method of use according to claim 4, characterized in that: The mass ratio of the coke to the coke melting agent is 1:(1.5-2).

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

10. The method of use according to claim 1, characterized in that: 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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