An incineration process for cracking waste liquid in the silicone industry

Abstract

This application relates to the technical field of the treatment of pyrolysis waste liquid of silicone, and specifically discloses an incineration process for pyrolysis waste liquid in the silicone industry. An incineration process for pyrolysis waste liquid in the silicone industry comprises the following steps: S1: The pyrolysis waste liquid is directly added into a rotary kiln for incineration after being encapsulated, and then enters a secondary combustion chamber for over-oxygen combustion; S2: The flue gas generated after combustion in step S1 is cooled by heat exchange and then cooled down to 500 - 600 °C, and then rapidly cooled down to 180 - 200 °C; S3: The flue gas after rapid cooling in step S2 is subjected to cyclone separation to obtain fly ash and separated flue gas, and the separated flue gas is discharged after dry acid removal and alkali washing acid removal treatment. The incineration process for pyrolysis waste liquid in the silicone industry of this application can be used for the treatment of various pyrolysis waste liquids of silicone, and has the advantages of high treatment efficiency and low content of dioxins in the flue gas.

Description

Technical Field

[0001] This application relates to the technical field of pyrolysis waste liquid treatment in the silicone industry. More specifically, it relates to a pyrolysis liquid incineration process in the silicone industry. Background Art

[0002] At present, a large amount of organic waste gas and waste liquid are generated in the production process of the silicone industry. These waste gases and waste liquids contain harmful components such as methyl chloride, tetramethylsilane, and high-boiling methylchlorodisilane. If they are directly sent to a wastewater treatment plant for treatment, not only is the treatment effect poor, but it is also uneconomical, wasting a large amount of resources, and the by-products generated are also difficult to treat.

[0003] Regarding the above problems, technicians have developed an incineration process to treat pyrolysis waste liquid. The pyrolysis waste liquid is transported through a closed pipeline to the waste liquid storage tank in the incineration workshop, and then injected into the incinerator by an atomizing spray gun. At a temperature of 900 - 1000 °C, the chlorosilane is decomposed at high temperature to generate substances such as silica, hydrogen chloride gas, and a small amount of chlorine gas that are easy to treat. However, since the silicone waste liquid will carry particulate solids, and the waste liquid will gradually solidify to form a slurry after being placed for a long time, it is very difficult to complete the feeding process using pipeline transportation. Moreover, due to the complex composition of the pyrolysis waste liquid, toxic and harmful substances such as dioxins are likely to be generated in the flue gas during the treatment process, and improper treatment of the subsequent acidic gas will cause secondary pollution.

[0004] With the continuous development and improvement of the process, the currently commonly used dioxin removal process is to use activated carbon injection adsorption combined with a bag filter to remove dioxins in the flue gas. However, this removal method can only be operated at the back end of the process, and the treatment cost and treatment difficulty are relatively high. Moreover, it has no good inhibitory effect on the dioxins generated in the front-end incineration process, and the total amount of dioxins generated in the flue gas is still at a relatively high level. Summary of the Invention

[0005] In order to reduce the content of dioxins in the flue gas during the incineration process, this application provides a pyrolysis waste liquid incineration process in the silicone industry.

[0006] This application provides a pyrolysis waste liquid incineration process in the silicone industry, adopting the following technical solutions:

[0007] A pyrolysis waste liquid incineration process in the silicone industry includes the following steps:

[0008] S1: Encapsulate the pyrolysis waste liquid and directly add it to a rotary kiln for incineration, and then enter a secondary combustion chamber for over-oxygen combustion;

[0009] S2: Cool the flue gas generated after combustion in step S1 through heat exchange to a temperature of 500 - 600 °C, and then rapidly cool it to a temperature of 180 - 200 °C;

[0010] S3: After subjecting the flue gas rapidly cooled in step S2 to cyclone separation, fly ash and separated flue gas are obtained. The separated flue gas undergoes dry desulfurization treatment to obtain desulfurized flue gas, and then the desulfurized flue gas undergoes activated carbon adsorption treatment to obtain adsorbed flue gas, and then the adsorbed flue gas undergoes alkali washing and desulfurization treatment and is discharged.

[0011] By adopting the above technical solution, since the cracking waste liquid in the silicone industry has a complex composition and will entrain a lot of particulate solids, it is very unstable during storage and is prone to solidification and caking. It is very difficult to complete the feeding operation by pipeline transportation. If the atomizing spray gun is used to inject into the rotary kiln, serious blockage often occurs and normal production cannot be carried out. In addition, if a diaphragm pump is used for feeding, it will also damage the diaphragm pump after long-term operation, and a large amount of heat will be released and acidic gas will be generated after the slurry contacts water. There are risks in using conventional feeding methods. In this application, the cracking waste liquid is integrally encapsulated and then fed into the kiln through the side door of the rotary kiln by a mobile device for incineration, which can efficiently and stably carry out the feeding operation for different forms of cracking waste liquid such as liquid, semi-solid slurry, and solid, meet the production requirements, and the overall production efficiency is higher.

[0012] Moreover, the cracking waste liquid is first incinerated in the rotary kiln, most of the organic matter can be cracked, and it can fully contact with the combustion gas driven by the rotary kiln, reducing the generation of dioxin components. Then the unburned organic matter and the particulate suspended organic matter entrained in the flue gas enter the secondary combustion chamber, and the organic matter is fully destroyed and decomposed by the strong over-oxygen combustion in the secondary combustion chamber. At the same time, the strong high-temperature over-oxygen combustion can decompose the existing dioxins, further controlling the content of dioxin components.

[0013] In addition, the high-temperature flue gas discharged from the rotary kiln and the secondary combustion chamber is cooled after heat exchange, and at this time, the dioxin precursors in the flue gas are prone to re-synthesize dioxin components again. In this application, the rapid cooling method is used to quickly cool the flue gas temperature to 180 - 200 °C, which can greatly inhibit the re-synthesis of dioxins in the flue gas, thereby reducing the content of dioxin components in the flue gas as a whole, facilitating subsequent treatment, saving the input of the activated carbon adsorption process at the back end, and being more energy-saving and environmentally friendly.

[0014] Preferably, the inclination angle of the rotary kiln is 1.5 - 2.5 degrees.

[0015] By adopting the above technical solution, the inclination angle of the rotary kiln is optimized and adjusted, so that the cracking waste moves along the rotary kiln at an appropriate speed towards the lower part of the rotary kiln, can fully contact with the combustion gas, ensure the decomposition degree of the organic matter, and inhibit the generation of components such as dioxin precursors to a certain extent.

[0016] Preferably, the rotational speed of the rotary kiln is 0.063 - 0.63 r / min.

[0017] By adopting the above technical solution and optimizing the rotational speed of the rotary kiln, the applicant found that with the above rotational speed, the cracking waste liquid can contact the combustion gas at an appropriate throwing speed, and some dioxin components and dioxin precursors generated during the incineration process can be decomposed, which is beneficial to reducing the content of dioxins in the flue gas.

[0018] Preferably, the inlet temperature of the rotary kiln is 800 - 900 °C, and the outlet temperature is 900 - 1100 °C.

[0019] By adopting the above technical solution and optimizing and adjusting the inlet temperature and outlet temperature of the rotary kiln, the appropriate temperature can accelerate the re-decomposition of the dioxin components generated in the flue gas, and at the same time inhibit the heterogeneous catalytic reaction on the surface of fly ash in the flue gas, reduce the synthesis amount of dioxin precursors, inhibit and block the synthesis of subsequent dioxin components, and reduce the content of dioxins in the subsequent flue gas.

[0020] Preferably, the maximum residence time of the material in the rotary kiln is 100 - 150 min.

[0021] By adopting the above technical solution and adjusting the maximum residence time of the material in the rotary kiln, on the premise of ensuring the energy cost, the organic matter and the dioxin components in the flue gas can be decomposed as fully as possible.

[0022] Preferably, in step S2, the rapid cooling includes the following steps:

[0023] 1), Atomizing the treatment liquid to form a spray mist;

[0024] 2), Mixing the heat-exchanged and cooled flue gas with the spray mist for heat exchange and cooling;

[0025] The treatment liquid is mainly made of the following raw materials in parts by weight: 500 - 650 parts of water, 15 - 20 parts of calcium disodium ethylene diamine tetraacetate, 5 - 10 parts of quaternary ammonium base, 3 - 7 parts of aminothiadiazole, and 2 - 5 parts of accelerator.

[0026] By adopting the above technical solution, in this application, the treatment liquid is atomized to form a spray mist. After the spray mist is in full contact with the high-temperature flue gas, it can be quickly cooled to 180 - 200 °C, inhibiting the oxidation reaction and condensation reaction of dioxin precursors. At the same time, under the catalytic action of the accelerator, the quaternary ammonium base and aminothiadiazole can exchange with the halogens in the dioxin precursors, capturing and trapping active elementary groups such as chloride ions.

[0027] In addition, aminothiadiazole can also undergo a nitrogen alkylation reaction with chloride ions to reduce the synthesis amount of chlorobenzenes and polychlorophenols. Moreover, calcium disodium ethylenediaminetetraacetate and quaternary ammonium bases can absorb chlorine gas and hydrogen chloride gas, reduce the dispersed chlorine source, inhibit the catalytic effect of the promoter on the synthesis of the original dioxin precursors in the flue gas, and at the same time ensure the elimination effect of the quaternary ammonium base and aminothiadiazole on the bound chlorine source, thereby greatly reducing the synthesis amount of dioxin components during the medium- and high-temperature process of the flue gas.

[0028] Preferably, the quaternary ammonium base is at least one of tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, and tetramethylammonium hydroxide.

[0029] By adopting the above technical solution, the type of the quaternary ammonium base is optimized and adjusted to enhance the capture and binding ability of the quaternary ammonium base to the bound chlorine source in the flue gas.

[0030] Preferably, the quaternary ammonium base is composed of tetrabutylammonium hydroxide and tetramethylammonium hydroxide in a molar ratio of (2.5 - 3):1.

[0031] By adopting the above technical solution, the composition ratio of the quaternary ammonium base is tested and optimized to balance the steric hindrance and chemical exchange ability of the quaternary ammonium base, further enhancing the chlorine source scavenging performance of the quaternary ammonium base and inhibiting the synthesis of dioxin components.

[0032] Preferably, the promoter is composed of copper powder and potassium carbonate in a molar ratio of (0.65 - 1):1.

[0033] By adopting the above technical solution, the composition ratio of the promoter is optimized and adjusted to greatly reduce the catalytic effect on the original dioxin precursors while ensuring the promoting effect of the promoter on the scavenging of the bound chlorine source, effectively inhibiting the synthesis process of dioxin components in the overall flue gas.

[0034] Preferably, the raw materials further include 0.8 - 1.5 parts by weight of saccharin.

[0035] By adopting the above technical solution, the present application discovers that after adding saccharin, under medium- and high-temperature reaction conditions, the nitrogen atom on the saccharin molecule can perform halogen binding with chlorobenzene and polychlorophenol dioxin precursors, thereby inhibiting and blocking the synthesis route of dioxin components and further reducing the synthesis amount of dioxin components during the medium- and high-temperature process of the flue gas.

[0036] In summary, the present application has the following beneficial effects:

[0037] 1. Since this application uses an overall encapsulation method to put the pyrolysis waste liquid into the rotary kiln, it can be applicable to pyrolysis waste liquids in various forms in the silicone industry. Then, through sufficient incineration in the rotary kiln and the secondary combustion chamber, the organic matter can be fully pyrolyzed. After the generated high-temperature flue gas is cooled by heat exchange and quenching, the secondary synthesis amount of dioxins in the flue gas at the medium and high temperature stages can be greatly inhibited.

[0038] 2. In this application, an atomization spraying process is preferably adopted to make the treatment liquid fully contact with the high-temperature flue gas, and the temperature of the flue gas is rapidly reduced by the vaporization heat exchange effect. At the same time, under the catalytic action of the accelerator, the quaternary ammonium base and aminothiadiazole in the treatment liquid exchange and capture the bound chlorine source in the dioxin precursor, inhibiting and blocking the secondary synthesis route of dioxin components, and greatly reducing the content of dioxins in the flue gas.

[0039] 3. The pyrolysis waste liquid incineration process in the silicone industry of this application can efficiently treat various pyrolysis waste liquids in the silicone industry, and the content of dioxins in the flue gas is very low, which is more environmentally friendly. Detailed implementation mode

[0040] The following further elaborates on this application in conjunction with examples.

[0041] The raw materials in the examples and comparative examples of this application are all ordinary commercially available products unless otherwise specified.

[0042] Example

[0043] Example 1

[0044] The pyrolysis waste liquid incineration process in the silicone industry of this example includes the following steps:

[0045] S1: The slurry-like pyrolysis waste liquid is encapsulated in a 200L plastic bucket, and then slowly lifted into the side door of the rotary kiln by an electric hoist for incineration. The inclination of the rotary kiln is designed to be 1.5 degrees, and the rotation speed is 0.063 r / min; the encapsulated pyrolysis waste liquid continuously moves downward in the rotary kiln. At this time, the inlet temperature of the rotary kiln is 800 °C, the outlet temperature is 900 °C, and the maximum residence time of the material is 150 min, so that the organic matter in the pyrolysis waste liquid is destroyed. The remaining unburned organic matter and the organic matter entrained by the suspended particles in the gas enter the secondary combustion chamber. Secondary air is introduced into the secondary combustion chamber for strong mixing, and the residence time exceeds 2 seconds, so that an over-oxygen combustion is formed in the secondary combustion chamber to make the pyrolysis waste liquid completely burn;

[0046] The furnace slag generated by the grate of the rotary kiln and the secondary combustion chamber is discharged through a slag discharger and collected into a space-woven ton bag by mechanical means for regular disposal;

[0047] S2: The flue gas generated after combustion in step S1 is cooled by heat exchange in a waste heat boiler and then cooled from 1100°C to 500°C, and then enters a quench tower. An atomizing spray device is provided in the quench tower. The atomizing spray device atomizes water to form water mist. The high-temperature flue gas is in direct contact with the atomized spray water mist. The flue gas can contact and evaporate and vaporize with the water mist within 1 second for heat exchange, and then is cooled to 180°C;

[0048] S3: The flue gas cooled in step S2 enters a cyclone separator for separation treatment to obtain fly ash and separated flue gas. The large-particle fly ash is trapped in the ash hopper below. The flue gas enters a dry desulfurization tower through a pipeline for dry desulfurization treatment. Slaked lime is added in the dry desulfurization tower. The separated flue gas is fully mixed and reacted with the added slaked lime; the feeding amount of slaked lime is controlled by a feeder, and the rotation speed of the feeder is controlled by a frequency converter to make the feeding amount more accurate;

[0049] Activated carbon powder is transported to the outlet flue of the dry desulfurization tower by an activated carbon conveying fan. Relying on the impact of the flue gas flow, the activated carbon powder is evenly dispersed in the flue gas, and heavy metals and dioxins in the flue gas are adsorbed to obtain adsorbed flue gas. The adsorbed activated carbon particles adhere to the filter bag wall of the bag filter, and then are discharged separately with the ash during the ash cleaning of the bag filter.

[0050] The adsorbed flue gas after activated carbon adsorption treatment is transported to an alkali washing and desulfurization tower. An alkali solution circulates in the alkali washing and desulfurization tower. The alkali solution reduces the temperature of the flue gas to 70°C, and at the same time further removes the acidic gas in the flue gas. Finally, it is discharged through an 80m high chimney.

[0051] In the pyrolysis waste liquid incineration process of the silicone industry in this embodiment, the waste heat boiler, quench tower, and cyclone dust collector adopt a direct ash discharge method and are equipped with a lock air device to prevent dust from flying. They are collected using space woven ton bags and treated regularly; the bag filter discharges ash separately. Each ash hopper adopts an automatic ash discharge method and is equipped with a heating device, and is collected mechanically into space woven ton bags and disposed of regularly.

[0052] Embodiment 2

[0053] The difference between the pyrolysis waste liquid incineration process of the silicone industry in this embodiment and that in Embodiment 1 is as follows:

[0054] 1), In step S1, the inclination of the rotary kiln is designed to be 2.5 degrees, and the rotation speed is 0.63 r / min; the packaged pyrolysis waste liquid continuously moves downward in the rotary kiln. At this time, the inlet temperature of the rotary kiln is 900°C, the outlet temperature is 1100°C, and the maximum residence time of the material is 100 min.

[0055] 2), in step S2, the flue gas generated after combustion in step S1 is cooled by heat exchange in a waste heat boiler and cooled from 1100 °C to 600 °C, and then enters a quench tower. An atomizing spray device is provided in the quench tower. The atomizing spray device atomizes water to form water mist. The high-temperature flue gas is in direct contact with the atomized spray water mist. The flue gas can contact and evaporate and vaporize with the water mist within 1 second for heat exchange, and then is cooled to 200 °C.

[0056] The rest is the same as in Example 1.

[0057] Example 3

[0058] The difference between the pyrolysis waste liquid incineration process of this example in the silicone industry and that of Example 1 lies in:

[0059] 1), in step S1, the inclination of the rotary kiln is designed to be 2 degrees, and the rotation speed is 0.35 r / min; the packaged pyrolysis waste liquid continuously moves downward to the rotary kiln. At this time, the inlet temperature of the rotary kiln is 850 °C, the outlet temperature is 1000 °C, and the maximum residence time of the material is 120 min.

[0060] 2), in step S2, the flue gas generated after combustion in step S1 is cooled by heat exchange in a waste heat boiler and cooled from 1100 °C to 550 °C, and then enters a quench tower. An atomizing spray device is provided in the quench tower. The atomizing spray device atomizes water to form water mist. The high-temperature flue gas is in direct contact with the atomized spray water mist. The flue gas can contact and evaporate and vaporize with the water mist within 1 second for heat exchange, and then is cooled to 195 °C.

[0061] The rest is the same as in Example 1.

[0062] Example 4

[0063] The difference between the pyrolysis waste liquid incineration process of this example in the silicone industry and that of Example 3 lies in:

[0064] In step S2, the rapid cooling includes the following steps:

[0065] 1), prepare the treatment liquid, and then spray the treatment liquid into the quench tower with an atomizing spray device to form a treatment liquid mist;

[0066] 2), mix the heat exchange-cooled flue gas with the treatment liquid mist for heat exchange;

[0067] The treatment liquid of this example is made of raw materials with the following weights: 500 kg of water, 15 kg of calcium disodium edetate, 5 kg of quaternary ammonium base, 3 kg of aminothiadiazole, and 2 kg of accelerator.

[0068] Among them, the quaternary ammonium base is tetramethylammonium hydroxide. The accelerator is copper powder.

[0069] The rest is the same as in Example 3.

[0070] Example 5

[0071] The difference between the pyrolysis waste liquid incineration process in the silicone industry of this example and that of Example 3 is as follows:

[0072] In step S2, the rapid cooling and temperature reduction includes the following steps:

[0073] 1), Prepare the treatment liquid, and then use an atomizing spraying device to form a treatment liquid mist and spray it into the quench tower;

[0074] 2), Mix the heat-exchanged and cooled flue gas with the treatment liquid mist for heat exchange;

[0075] The treatment liquid of this example is made of raw materials with the following weights: 650 kg of water, 20 kg of calcium disodium ethylene diamine tetraacetate, 10 kg of quaternary ammonium base, 7 kg of aminothiadiazole, and 5 kg of accelerator.

[0076] Among them, the quaternary ammonium base is tetrapropylammonium hydroxide. The accelerator is Pb powder.

[0077] The rest is the same as that of Example 3.

[0078] Example 6

[0079] The difference between the pyrolysis waste liquid incineration process in the silicone industry of this example and that of Example 3 is as follows:

[0080] In step S2, the rapid cooling and temperature reduction includes the following steps:

[0081] 1), Prepare the treatment liquid, and then use an atomizing spraying device to form a treatment liquid mist and spray it into the quench tower;

[0082] 2), Mix the heat-exchanged and cooled flue gas with the treatment liquid mist for heat exchange;

[0083] The treatment liquid of this example is made of raw materials with the following weights: 600 kg of water, 18 kg of calcium disodium ethylene diamine tetraacetate, 8.5 kg of quaternary ammonium base, 5 kg of aminothiadiazole, and 3.5 kg of accelerator.

[0084] Among them, the quaternary ammonium base is tetrapropylammonium hydroxide. The accelerator is Pb powder.

[0085] The rest is the same as that of Example 3.

[0086] Example 7

[0087] The difference between the pyrolysis waste liquid incineration process in the silicone industry of this example and that of Example 6 is that in the raw materials of the treatment liquid, the quaternary ammonium base is composed of tetrabutylammonium hydroxide and tetramethylammonium hydroxide in a molar ratio of 2.5:1, and the rest is the same as that of Example 6.

[0088] Example 8

[0089] The difference between the pyrolysis waste liquid incineration process of the silicone industry in this example and that in Example 6 is that in the raw material of the treatment liquid, the quaternary ammonium base is composed of tetrabutylammonium hydroxide and tetramethylammonium hydroxide in a molar ratio of 3:1, and the rest is the same as that in Example 6.

[0090] Example 9

[0091] The difference between the pyrolysis waste liquid incineration process of the silicone industry in this example and that in Example 8 is that in the raw material of the treatment liquid, the promoter is composed of copper powder and potassium carbonate in a molar ratio of 1:1, and the rest is the same as that in Example 8.

[0092] Example 10

[0093] The difference between the pyrolysis waste liquid incineration process of the silicone industry in this example and that in Example 8 is that in the raw material of the treatment liquid, the promoter is composed of copper powder and potassium carbonate in a molar ratio of 0.65:1, and the rest is the same as that in Example 8.

[0094] Example 11

[0095] The difference between the pyrolysis waste liquid incineration process of the silicone industry in this example and that in Example 10 is that the raw material of the treatment liquid further includes 0.8 kg of saccharin, and the rest is the same as that in Example 10.

[0096] Example 12

[0097] The difference between the pyrolysis waste liquid incineration process of the silicone industry in this example and that in Example 10 is that the raw material of the treatment liquid further includes 1.5 kg of saccharin, and the rest is the same as that in Example 10.

[0098] Comparative Example

[0099] Comparative Example 1

[0100] The difference between the pyrolysis waste liquid incineration process of the silicone industry in this comparative example and that in Example 1 is as follows:

[0101] 1), In step S1, after filtering the pyrolysis waste liquid, a liquid material and a solid material are obtained. The solid aggregate is sent into the rotary kiln through a belt conveyor, and the liquid material is sent into the rotary kiln by a diaphragm pump.

[0102] 2), In step S2, the flue gas generated after combustion in step S1 is cooled by heat exchange in a waste heat boiler and cooled from 1100 °C to 200 °C.

[0103] The rest is the same as that in Example 1.

[0104] Comparative Example 2

[0105] The difference between the pyrolysis waste liquid incineration process in the silicone industry of this comparative example and that of Example 3 lies in:

[0106] In step S2, the rapid cooling includes the following steps:

[0107] 1), Prepare the treatment liquid, and then use an atomizing spraying device to form a treatment liquid mist and spray it into the quench tower;

[0108] 2), Mix the heat-exchanged and cooled flue gas with the treatment liquid mist for heat exchange;

[0109] The treatment liquid of this comparative example is made of raw materials with the following weights: 515 kg of water, 5 kg of quaternary ammonium base, 3 kg of aminothiadiazole, and 2 kg of accelerator.

[0110] Among them, the quaternary ammonium base is tetramethylammonium hydroxide. The accelerator is copper powder.

[0111] Comparative Example 3

[0112] The difference between the pyrolysis waste liquid incineration process in the silicone industry of this comparative example and that of Example 3 lies in:

[0113] In step S2, the rapid cooling includes the following steps:

[0114] 1), Prepare the treatment liquid, and then use an atomizing spraying device to form a treatment liquid mist and spray it into the quench tower;

[0115] 2), Mix the heat-exchanged and cooled flue gas with the treatment liquid mist for heat exchange;

[0116] The treatment liquid of this comparative example is made of raw materials with the following weights: 505 kg of water, 15 kg of calcium disodium edetate, 3 kg of aminothiadiazole, and 2 kg of accelerator.

[0117] Among them, the accelerator is copper powder.

[0118] Comparative Example 4

[0119] The difference between the pyrolysis waste liquid incineration process in the silicone industry of this comparative example and that of Example 3 lies in:

[0120] In step S2, the rapid cooling includes the following steps:

[0121] 1), Prepare the treatment liquid, and then use an atomizing spraying device to form a treatment liquid mist and spray it into the quench tower;

[0122] 2), Mix the heat-exchanged and cooled flue gas with the treatment liquid mist for heat exchange;

[0123] The treatment liquid of this comparative example is made from raw materials with the following weights: 503 kg of water, 15 kg of calcium disodium ethylene diamine tetraacetate, 5 kg of quaternary ammonium base, and 2 kg of accelerator.

[0124] Among them, the quaternary ammonium base is tetramethylammonium hydroxide. The accelerator is copper powder.

[0125] Comparative Example 5

[0126] The difference between the pyrolysis waste liquid incineration process in the silicone industry of this comparative example and that of Example 3 lies in:

[0127] In step S2, the rapid cooling includes the following steps:

[0128] 1), Prepare the treatment liquid, and then use an atomizing spraying device to form a treatment liquid mist and spray it into the quench tower;

[0129] 2), Make the heat-exchanged and cooled flue gas mix with the treatment liquid mist for heat exchange;

[0130] The treatment liquid of this comparative example is made from raw materials with the following weights: 508 kg of water, 15 kg of calcium disodium ethylene diamine tetraacetate, and 2 kg of accelerator.

[0131] Among them, the accelerator is copper powder.

[0132] Comparative Example 6

[0133] The difference between the pyrolysis waste liquid incineration process in the silicone industry of this comparative example and that of Example 3 lies in:

[0134] In step S2, the rapid cooling includes the following steps:

[0135] 1), Prepare the treatment liquid, and then use an atomizing spraying device to form a treatment liquid mist and spray it into the quench tower;

[0136] 2), Make the heat-exchanged and cooled flue gas mix with the treatment liquid mist for heat exchange;

[0137] The treatment liquid of this comparative example is made from raw materials with the following weights: 508 kg of water, 15 kg of calcium hydroxide. The average particle size of calcium hydroxide is 200 nm.

[0138] Performance detection test

[0139] Detection method

[0140] Take the cracked waste liquid of the silicone industry in slurry form and test the time required to treat each ton of cracked waste liquid according to the incineration process of the cracked waste liquid of the silicone industry in Examples 1-12 and Comparative Examples 1-6; test the content of dioxin-like substances in the flue gas discharged according to the standard HJ-77.2-2008, and convert it into the equivalent concentration (TEQ) equivalent to the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin. The comprehensive test results are shown in Table 1.

[0141] Table 1 Comprehensive test data of the incineration process of the cracked waste liquid of the silicone industry in Examples 1-12 and Comparative Examples 1-6

[0142]

[0143] Analysis of Examples 1-3 and Comparative Example 1 and combined with Table 1 shows that by adopting the feeding method of overall encapsulation, the cracked waste liquid of silicone in various forms can be treated, and the overall production efficiency is greatly improved. For the same one-ton material treatment, the production time of Example 3 saves about 28.9% compared with Comparative Example 1. Moreover, compared with the conventional cooling method, after adopting the primary heat exchange cooling plus secondary rapid cooling treatment, the secondary synthesis of dioxin components in the medium and high temperature stage is inhibited. It can be seen that the dioxin content in Example 3 is reduced from 0.78 ng to 0.030 ng compared with Comparative Example 1, which is far lower than the national standard of 0.5 ng and also lower than the EU standard of 0.1 ng, making it more environmentally friendly.

[0144] Analysis of Examples 4-6, Comparative Examples 2-6 and combined with Table 1 shows that after the treatment liquid of the present application is atomized and mixed with high-temperature flue gas, on the one hand, the flue gas temperature can be rapidly reduced, and on the other hand, the combined chlorine and free chlorine in the flue gas can be effectively captured, inhibiting and blocking the secondary synthesis process of dioxin precursors, and greatly reducing the dioxin content in the flue gas. Moreover, the applicant found that when only calcium disodium ethylenediaminetetraacetate is added, although it has a certain neutralizing and eliminating effect on the free chlorine source, it has no good effect on the combined chlorine. In addition, when only quaternary ammonium base and aminothiadiazole are added, although the combined chlorine content is effectively controlled, the catalysis of the accelerator is not inhibited at the same time, resulting in a slight increase in the dioxin content. And, compared with the conventional calcium hydroxide adsorbent, the dioxin content in the flue gas treated with the treatment liquid of the present application has decreased by about 57.7%, and the removal effect is very obvious.

[0145] Analysis of Examples 7-8 and Examples 9-10 and in combination with Table 1 shows that by optimizing and adjusting the composition ratio of quaternary ammonium base and promoter, the chlorine removal effect of the treatment liquid is further improved, the contents of combined chlorine source and free chlorine source in the flue gas are reduced to a relatively low level, and the secondary synthesis process of dioxin components is hindered. It can be seen that compared with Example 6, the content of dioxin in the flue gas of Example 10 is decreased to 0.0095 ng.

[0146] Analysis of Example 11 and Example 12 and in combination with Table 1 shows that by adding saccharin, the halogen combination of chlorine-containing dioxin precursors is carried out by using the high activity of nitrogen atoms under high temperature conditions, further blocking the synthesis of dioxin and reducing the total amount of dioxin in the flue gas.

[0147] This specific embodiment is only an explanation of the present application, and it does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. An incineration process for cracking waste liquid in the silicone industry, characterized in that, it comprises the following steps: S1: Encapsulate the cracking waste liquid and directly add it into a rotary kiln for incineration, and then enter a secondary combustion chamber for overoxygen combustion; S2: Cool the flue gas generated after combustion in step S1 through heat exchange to a temperature of 500 - 600 °C, and then rapidly cool it to a temperature of 180 - 200 °C; S3: After the flue gas rapidly cooled and cooled in step S2 is treated by cyclone separation to obtain fly ash and separated flue gas, the separated flue gas is treated by dry desulfurization to obtain desulfurized flue gas, then the desulfurized flue gas is treated by activated carbon adsorption to obtain adsorbed flue gas, and then the adsorbed flue gas is treated by alkali washing and desulfurization and then discharged; In the said step S2, the rapid cooling and temperature reduction comprises the following steps: 1). Atomize the treatment liquid to form a spray water mist; 2). Mix the flue gas after heat exchange cooling with the spray water mist and conduct heat exchange for temperature reduction; The said treatment liquid is mainly made of raw materials in the following weight parts: 500 - 650 parts of water, 15 - 20 parts of calcium disodium ethylene diamine tetraacetate, 5 - 10 parts of quaternary ammonium base, 3 - 7 parts of aminothiadiazole, 2 - 5 parts of accelerator.

2. An incineration process for cracking waste liquid in the silicone industry according to claim 1, characterized in that, the inclination angle of the said rotary kiln is 1.5 - 2.5 degrees.

3. An incineration process for cracking waste liquid in the silicone industry according to claim 1, characterized in that, the rotation speed of the said rotary kiln is 0.063 - 0.63 r / min.

4. An incineration process for cracking waste liquid in the silicone industry according to claim 1, characterized in that, the inlet temperature of the said rotary kiln is 800 - 900 °C, and the outlet temperature is 900 - 1100 °C.

5. An incineration process for cracking waste liquid in the silicone industry according to claim 1, characterized in that, the maximum residence time of materials in the said rotary kiln is 100 - 150 min.

6. An incineration process for cracking waste liquid in the silicone industry according to claim 1, characterized in that, the said quaternary ammonium base is at least one of tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, and tetramethylammonium hydroxide.

7. An incineration process for cracking waste liquid in the silicone industry according to claim 6, characterized in that, the said quaternary ammonium base is composed of tetrabutylammonium hydroxide and tetramethylammonium hydroxide in a molar ratio of (2.5 - 3):

1.

8. An incineration process for cracking waste liquid in the silicone industry according to claim 1, characterized in that, the said accelerator is composed of copper powder and potassium carbonate in a molar ratio of (0.65 - 1):

1.

9. An incineration process for cracking waste liquid in the silicone industry according to claim 1, characterized in that, the said raw materials further include 0.8 - 1.5 weight parts of saccharin.

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