A gas circulation system for a ceramist kiln

Abstract

The application provides a gas circulation system of a ceramsite calcining kiln, and belongs to the technical field of pollution gas treatment. The gas circulation system of the ceramsite calcining kiln comprises a drying hot air section, a preheating section, a sintering section, a soaking section, a rapid cooling section and a slow cooling section arranged in sequence, the drying temperature of the drying hot air section is 100-200 DEG C, the preheating temperature of the preheating section is 300-900 DEG C, the oxygen content in the preheating section is 10%-17%, the preheating section is internally provided with a dioxin inhibiting part, the dioxin inhibiting part comprises a first inhibiting part provided with ammonium sulfate solid and a second inhibiting part provided with organic amine solid base, and the application further comprises a hot air circulation system 1 and a hot air circulation system 2. The gas circulation system has good dioxin gas treatment capacity, high heat source utilization rate, reasonable structure, and performs dust removal treatment on the exhaust gas flow, and the discharged gas has no pollution to the environment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of contaminated gas treatment, and particularly relates to a gas circulation system of a ceramsite calcination kiln. BACKGROUND

[0002] Dioxin is very toxic and has carcinogenic effect, and is the most toxic compound among the by-products of unintentional synthesis currently found, and is called "the strongest poison on the earth". It is very stable below 705 DEG C, starts to decompose above 705 DEG C, has very low vapor pressure, does not volatilize at general ambient temperature, is resistant to high temperature, and is difficult to oxidize, decompose or hydrolyze, and has an ultra-long physical, chemical or biological degradation period, and needs dozens of years or even longer time. Human beings and other animals and plants have no function or condition to decompose or oxidize dioxin, so the toxicity of dioxin is difficult to eliminate in the environment, and once generated or contaminated, the dioxin can only be transferred and accumulated, and is difficult to transform, and often is transmitted and enriched with food chain, and brings disastrous influence to human beings and various animals and plants.

[0003] Dioxin is mainly generated in the preheating layer in the sintering process, and the main reasons can be summarized as follows: 1) the temperature of the layer is 200-800 DEG C, and the temperature of 200-650 DEG C is the best temperature interval for generation of dioxin, 2) a large amount of volatile organic matters such as dioxin precursors are condensed in the layer from the combustion layer, and the temperature and oxidation environment of the layer are beneficial to generation of dioxin, 3) with the downward movement of the flame front and the downward movement of the airflow, a large amount of carbon black, chlorine elements and transition metal salts migrate and enrich to the preheating layer, and provide raw materials and catalysts for generation of dioxin in the layer.

[0004] The dioxin gas treatment system in the prior art has the following defects: 1) the low-temperature de novo synthesis of dioxin or organic gas is not considered; 2) the cooled flue gas is directly mixed with dry cold air, and the wind flow system is not divided into clean wind flow and contaminated wind flow two parts, and the burden of environmental protection and treatment is reduced; 3) the generation of dioxin is not directly inhibited in the sintering process, and a large amount of dioxin is generated, and it is difficult to ensure 100% removal of dioxin in the subsequent removal process. SUMMARY

[0005] The present application aims to overcome the above technical deficiencies, and provides a gas circulation system of a ceramsite calcination kiln, so as to solve the technical problems of a large amount of dioxin generated in the process of ceramsite sintering, steel processing and the like, and low dioxin removal rate in the prior art.

[0006] In order to achieve the above technical purpose, the embodiments of the present application provide the following technical scheme.

[0007] A kind of gas circulation system of ceramsite calcination kiln, including drying hot air section, preheating section, firing section, soaking section, quenching section, slow cooling section arranged in sequence, the drying temperature of the drying hot air section is 100-200 ℃, the preheating temperature of the preheating section is 300-900 ℃, the oxygen content in the preheating section is 10%-17%, the preheating section is built-in dioxin inhibiting part, the dioxin inhibiting part includes the first inhibiting part of being equipped with ammonium sulfate solid, the second inhibiting part of being equipped with organic amine solid base, the organic amine solid base is the silicon dioxide of being immobilized with organic silane, and the organic silane contains organic amine group.The organic amine group is one of triethylamine, triethanolamine.The liquid organic amine is not easy to store and transport, install, operate, so solid organic amine solid base is used.The amount of use of the ammonium sulfate solid is 130-280 g / m3 flue gas, and the amount of use of the organic amine solid base is 230-300 g / m3 flue gas.

[0008] The gas circulation system further includes hot air circulation system 1, hot air circulation system 2, one input end of the hot air circulation system 1 is communicated with the quenching section, one output end is communicated with the upper end of firing section and or soaking section and or preheating section, the other input end of the hot air circulation system 1 is communicated with the lower end of the preheating section, and the other output end is communicated with the upper end of firing section and or soaking section, one end of the hot air circulation system 2 is communicated with the slow cooling section, and the other end is communicated with the drying hot air section.

[0009] In the application, by hot air circulation system 1, hot air circulation system 2, gas transmission between different sections is carried out, it needs to be noted that drying hot air section, preheating section, firing section, soaking section, quenching section, slow cooling section are provided with retractable isolation wall for isolating gas of different components.

[0010] The drying temperature of the drying hot air section in the application is 100-200 DEG C, because the minimum temperature of dioxin generation is 250 DEG C, the material to be processed is dried in the low temperature section first, then processed in the preheating section, the temperature of the preheating section is 300-900 DEG C, which is relatively beneficial to the generation of dioxin, 350 DEG C is the optimal temperature for dioxin generation, the substances capable of generating dioxin are reacted in the preheating section, then the gas containing dioxin is transported to the high temperature section, the burning section and the soaking section, in the high temperature environment, the dioxin gas is decomposed into harmless gas substances. The dioxin inhibiting part is additionally arranged in the preheating section for forming dioxin, which can inhibit the release of dioxin gas in the material processing process. NH3 and other inhibiting gases are decomposed from ammonium sulfate during the heating process in the preheating section, react with acidic gases Cl2 and HCl, reduce the raw materials for dioxin synthesis, hinder the occurrence of Deacon reaction, thereby reducing the generation amount of dioxin. In addition, porous silicon dioxide is used as a carrier to load organic silane containing an organic amine group, the organic amine group is one of triethylamine and triethanolamine, the triethylamine and triethanolamine contain a nitrogen-containing functional group -NH2, the organic amine group functional group can form a complex with the metal active sites on the surface of the fly ash generated in the sintering process, be converted into nitride, weaken the formation trend of dioxin, and further reduce the formation of dioxin in the sintering process.

[0011] In addition, the content of oxygen in a suitable range can improve the speed of carbon oxidation, accelerate the generation of organic chlorides, and is a key factor for the de novo synthesis of dioxin.

[0012] Preferably, the gas circulation system further comprises a water cooling system, an input end of the water cooling system is in communication with the burning section and / or the soaking section, and a dust removal device is arranged at an output end of the water cooling system for desulfurization, denitrification, active carbon spraying and dust removal. The purpose of arranging the dust removal device is mainly to treat the output gas, remove the sulfur-containing, nitrogen-containing gas and solid particles in the output gas, and then discharge the output gas into the atmosphere. The sulfur-containing and nitrogen-containing gas can be absorbed by liquid and solid absorbents according to the prior art, and the solid substances can be adsorbed by active carbon.

[0013] Preferably, an input end of the hot air circulation system 1 is in communication with the quenching section, an output end is in communication with the upper ends of the burning section, the soaking section and the preheating section, and another input end of the hot air circulation system 1 is in communication with the lower end of the preheating section, and another output end is in communication with the upper ends of the burning section and the soaking section, so that the gas in the preheating section is input into the burning section and the soaking section.

[0014] Preferably, an input end of the hot air circulation system 1 is communicated with the quenching section, an output end is communicated with the sintering section, the soaking section and the upper end of the preheating section, another input end of the hot air circulation system 1 is communicated with the lower end of the preheating section, and another output end is communicated with the upper end of the sintering section, so that the gas of the preheating section is input to the sintering section, and the output end of the soaking section is communicated with the drying hot air section. The heat source is saved, and the secondary utilization rate of the heat source is improved.

[0015] Preferably, the temperature of the sintering section is 1100-1130℃, and the temperature of the soaking section is 1120℃.

[0016] Preferably, the temperature of the slow cooling section is 100-180℃, and the temperature of the quenching section is 700-900℃, so that the dioxin gas is avoided to be generated again in the process of temperature reduction.

[0017] Preferably, the drying hot air section comprises a drum drying section and an exhaust drying section, the temperature in the drum drying section is 100-150℃, the temperature of the exhaust drying section is 150-200℃, and the output end of the exhaust drying section is communicated with the sintering section and / or the soaking section. In this way, the harmful gas generated at about 200℃ is directly input to a higher temperature area, so that the harmful gas is decomposed, and the treatment effect of the harmful gas can be further ensured.

[0018] The present application has at least the following beneficial effects:

[0019] In the above scheme, the preheating section with a temperature of 300-900℃ is arranged in the gas circulation system, so that the dioxin gas can be released at a low temperature, and the dioxin inhibition part is arranged in the low temperature section, the ammonia gas decomposed from the ammonium sulfate at high temperature reacts with the acid gas Cl2 and HCl, so that the raw material for synthesizing dioxin is reduced, the organic amine group can form a complex with the metal active sites on the surface of the fly ash generated in the sintering process, and is converted into a nitride, so that the formation trend of dioxin is weakened, the formation of dioxin in the sintering process is further reduced, and the raw material for generating dioxin is consumed. In this way, the total amount of dioxin to be treated in the sintering process is greatly reduced, the generation amount of dioxin in the sintering process is fundamentally reduced, and the content of dioxin in the exhaust gas is greatly reduced through high temperature reaction and rapid cooling, and the gas circulation system does not emit dioxin gas.

[0020] The gas circulation system has good dioxin gas treatment capacity, high heat source utilization rate, reasonable structure, and dust removal treatment is performed on the exhaust gas flow, and the exhaust gas is pollution-free to the environment. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments description. Obviously, the drawings described below only are some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0022] Figure 1 Structure diagram of a gas circulation system of a ceramist calcining kiln provided in the present application;

[0023] Figure 2 Another structure diagram of a gas circulation system of a ceramist calcining kiln provided in the present application. DETAILED DESCRIPTION

[0024] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will combine the drawings of the embodiments of the present application to make a clear and complete description of the technical solutions of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those skilled in the art without any creative effort are within the protection scope of the present application.

[0025] Embodiment 1

[0026] Please refer to Figure 1 A gas circulation system of a ceramist calcining kiln, comprising a drying hot air section, a preheating section, a firing section, a soaking section, a rapid cooling section and a slow cooling section arranged in sequence, the drying temperature of the drying hot air section is 200℃, the preheating temperature of the preheating section is 900℃, the oxygen content in the preheating section is 17%, the preheating section is provided with a dioxin inhibiting part, the dioxin inhibiting part comprises a first inhibiting part filled with ammonium sulfate solid and a second inhibiting part filled with organic amine solid base, the organic amine solid base is silica solid loaded with organic silane, and the organic silane contains an organic amine group. The organic amine group is triethylamine. The amount of the ammonium sulfate solid is 130g per cubic meter of flue gas, and the amount of the organic amine solid base is 300g per cubic meter of flue gas.

[0027] The gas circulation system further comprises a hot air circulation system 1 and a hot air circulation system 2, one input end of the hot air circulation system 1 is communicated with the rapid cooling section, one output end is communicated with the upper end of the firing section, the soaking section, the preheating section and the drying hot air section, another input end of the hot air circulation system 1 is communicated with the lower end of the preheating section, and another output end is communicated with the upper end of the firing section and the soaking section. The drying hot air section comprises a drum drying section and a suction drying section, the temperature in the drum drying section is 100℃, and the temperature in the suction drying section is 150℃. One end of the hot air circulation system 2 is communicated with the slow cooling section, and the other end is communicated with the drum drying section.

[0028] The gas circulation system further comprises a water cooling system, an input end of the water cooling system being communicated with the firing section and or the soaking section, and an output end being provided with a dust removal device for desulfurization, denitrification, active carbon spraying and dust removal.

[0029] The temperature of the firing section is 1100℃, and the temperature of the soaking section is 1120℃.

[0030] The temperature of the slow cooling section is 100℃, and the temperature of the rapid cooling section is 700℃, and the gas needs to be rapidly cooled from the rapid cooling section to the slow cooling section to avoid the generation of dioxin gas in the process of temperature reduction.

[0031] In addition, the gas of the drying section and the exhaust section can be directly discharged.

[0032] Overall, after the material enters the kiln, drying is performed in the drying section and the exhaust section, dioxin gas is released in the preheating section, the dioxin gas generated in the preheating section enters the firing section and the soaking section through the hot air circulation system 1 for high-temperature treatment of dioxin, and the excess hot gas in the rapid cooling section can enter the firing section, the soaking section, the preheating section and the drying hot air section through the hot air circulation system 1 for secondary use of the related heat. Meanwhile, the gas flow in the firing section is cooled by cold water treatment, and then discharged after dust removal treatment.

[0033] Example 2

[0034] Please refer to Figure 2 A gas circulation system of a ceramsite calcination kiln, comprising a drying hot air section, a preheating section, a firing section, a soaking section, a rapid cooling section and a slow cooling section arranged in sequence, the drying temperature of the drying hot air section is 200℃, the preheating temperature of the preheating section is 900℃, the oxygen content in the preheating section is 17%, the preheating section is provided with a dioxin inhibition part, the dioxin inhibition part comprises a first inhibition part provided with ammonium sulfate solid and a second inhibition part provided with organic amine solid base, the organic amine solid base is silica supported with organic silane, and the organic silane contains an organic amine group. The organic amine group is triethanolamine. The amount of the ammonium sulfate solid is 280g per cubic meter of flue gas, and the amount of the organic amine solid base is 230g per cubic meter of flue gas.

[0035] The gas circulation system further comprises a hot air circulation system 1 and a hot air circulation system 2, one input end of the hot air circulation system 1 is communicated with the quenching section, one output end is communicated with the sintering section, the soaking section and the upper end of the preheating section, another input end of the hot air circulation system 1 is communicated with the lower end of the preheating section, and another output end is communicated with the upper end of the sintering section, one end of the hot air circulation system 2 is communicated with the slow cooling section, and the other end is communicated with the drying hot air section. The drying hot air section comprises a drum drying section and a suction drying section, the temperature in the drum drying section is 150℃, the temperature of the suction drying section is 200℃, the output end of the suction drying section is communicated with the sintering section and the soaking section, one output end of the soaking section is communicated with the suction drying section, and the flue gas of the drum drying section is directly discharged.

[0036] The gas circulation system further comprises a water cooling system, one input end of the water cooling system is communicated with the sintering section and / or the soaking section, and the output end is provided with a dust removal device for desulfurization, denitrification, active carbon spraying and dust removal.

[0037] The temperature of the sintering section is 1130℃, and the temperature of the soaking section is 1120℃.

[0038] The temperature of the slow cooling section is 180℃, and the temperature of the quenching section is 900℃, so that the flue gas is rapidly cooled from the quenching section to the slow cooling section, so as to avoid the generation of dioxin gas in the process of temperature reduction.

[0039] Example 3

[0040] The example is the same as example 1, and the difference lies in that the amount of the ammonium sulfate solid in the example is 200g per cubic meter of flue gas, the amount of the organic amine solid base is 260g per cubic meter of flue gas, the drying temperature of the drying hot air section is 150℃, the preheating temperature of the preheating section is 600℃, the oxygen content in the preheating section is 15%, the temperature of the sintering section is 1120℃, the temperature of the slow cooling section is 150℃, the temperature of the quenching section is 800℃, the temperature in the drum drying section is 130℃, and the temperature of the suction drying section is 170℃.

[0041] Comparative Example 1

[0042] The comparative example is the same as example 1, and the difference lies in that the dioxin inhibition part in the comparative example only comprises a first inhibition part provided with the ammonium sulfate solid.

[0043] Comparative Example 2

[0044] The comparative example is the same as example 1, and the difference lies in that the dioxin inhibition part in the comparative example only comprises a second inhibition part provided with the organic amine solid base.

[0045] Comparative Example 3

[0046] The comparative example is the same as example 1, except that the oxygen content in the preheating section is 6% in the comparative example.

[0047] Comparative example 4

[0048] The comparative example is the same as example 1, except that the amount of ammonium sulfate solid used is 100 g / m3 of flue gas and the amount of solid base of organic amine used is 350 g / m3 of flue gas in the comparative example.

[0049] The inhibition rate of dioxin in the preheating section in examples 1 to 3 and comparative examples 1 to 3 is tested using sintering fly ash, and the specific data are as follows:

[0050]

[0051] From the above data, it can be seen that the preheating section of the present application can effectively inhibit the generation of dioxin gas in the sintering process, and after high temperature treatment, the discharged gas does not contain harmful gases such as dioxin.

[0052] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A gas circulation system for a ceramsite firing kiln, comprising a drying hot air section, a preheating section, a firing section, a homogenizing section, a rapid cooling section, and a slow cooling section arranged sequentially, characterized in that, The drying temperature of the hot air drying section is 100-200℃, the preheating temperature of the preheating section is 300-900℃, the oxygen content in the preheating section is 10%-17%, the preheating section has a built-in dioxin suppression section, the dioxin suppression section includes a first suppression section containing ammonium sulfate solid and a second suppression section containing organic amine solid alkali, the amount of ammonium sulfate solid is 130-280g / m³ flue gas, the amount of organic amine solid alkali is 230-300g / m³ flue gas, the temperature of the firing section is 1100-1130℃, the temperature of the homogenizing section is 1120℃, and the temperature of the slow cooling section is 100-180℃; The gas circulation system further includes a hot air circulation system 1 and a hot air circulation system 2. One input end of the hot air circulation system 1 is connected to the rapid cooling section, and one output end is connected to the upper end of the firing section and / or the homogenizing section and / or the preheating section. Another input end of the hot air circulation system 1 is connected to the lower end of the preheating section, and another output end is connected to the upper end of the firing section and / or the homogenizing section. One end of the hot air circulation system 2 is connected to the slow cooling section, and the other end is connected to the drying hot air section. The gas circulation system also includes a water cooling system. The input end of the water cooling system is connected to the firing section and / or the homogenizing section, and the output end is equipped with a dust removal device for desulfurization, denitrification, activated carbon spraying, and dust removal.

2. The gas circulation system of the ceramsite roasting kiln according to claim 1, characterized in that, The organic amine solid base is silicon dioxide supported on an organosilane, and the organosilane contains an organic amine group.

3. The gas circulation system of the ceramsite firing kiln according to claim 2, characterized in that, The organic amine group is one of triethylamine or triethanolamine.

4. The gas circulation system of the ceramsite roasting kiln according to claim 2, characterized in that, One input end of the hot air circulation system 1 is connected to the quench section, and one output end is connected to the upper ends of the firing section, the soaking section, and the preheating section. Another input end of the hot air circulation system 1 is connected to the lower end of the preheating section, and another output end is connected to the upper ends of the firing section and the soaking section, so that the gas in the preheating section is input into the firing section and the soaking section.

5. The gas circulation system of the ceramsite roasting kiln according to claim 2, characterized in that, One input end of the hot air circulation system 1 is connected to the quenching section, and one output end is connected to the upper ends of the firing section, the soaking section, and the preheating section. Another input end of the hot air circulation system 1 is connected to the lower end of the preheating section, and another output end is connected to the upper end of the firing section, so that the gas from the preheating section is input into the firing section. The output end of the soaking section is connected to the drying hot air section.

6. The gas circulation system of the ceramsite roasting kiln according to claim 1, characterized in that, The drying hot air section includes a blowing section and an extraction section. The temperature in the blowing section is 100-150℃, and the temperature in the extraction section is 150-200℃. The output end of the extraction section is connected to the firing section and / or the homogenizing section.

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