Method and device for harmless disposal of sludge by cyclone melting pyrolysis assisted by rice husk

Abstract

The application discloses a rice hull auxiliary sludge pyrolysis gasification cyclone melting harmless treatment method and device, and relates to the field of sludge treatment. The method comprises the following steps: feeding sludge and rice hull auxiliary materials into a roaster through a bunker respectively to generate a low-temperature pyrolysis reaction, feeding solid-phase products into a vertical gasification furnace to generate a gasification reaction with air, conveying gasification residual coke to a reformer to generate a catalytic reforming reaction with gasification gas overflowing from a gas outlet of the vertical gasification furnace, and simultaneously, using roasting gas as a reforming medium by passing the roasting gas into the reformer; the gasification residual coke after the catalytic reforming is pulverized by a crusher and then sprayed into a cyclone melting furnace to generate a combustion reaction with high-temperature air, and additionally, the gasification gas after the reforming is fed to assist combustion, so that ash contained in the gasification residual coke and fly ash carried by the gasification gas are completely melted and liquefied to effectively solid-solute heavy metals in the sludge. In the application, the rice hull is used to assist the sludge, various sludge can be completely and harmlessly treated, and the whole system is energy self-sufficient.

Description

TECHNICAL FIELD

[0001] The present application relates to a sludge thermochemical harmless disposal method and device, in particular to a rice husk assisted sludge pyrolysis gasification cyclone melting harmless disposal method and device. BACKGROUND

[0002] Sludge is mainly divided into municipal sludge and industrial sludge according to the source, which is a non-homogeneous organic body with complex components and containing various pollutants. The sludge usually has a high water content and contains a certain amount of organic pollutants such as viruses, pathogenic bacteria, insect eggs and parasites; meanwhile, the sludge contains a high content of inorganic components, and the existence of excessive arsenic (As), chromium (Cr), cadmium (Cd), lead (Pb), mercury (Hg), copper (Cu), nickel (Ni) and zinc (Zn) heavy metals causes great difficulty in the disposal of sludge. At present, the disposal methods of sludge mainly include: (1) landfill, which has low treatment cost and strong practicality, but the landfill method takes a long time and the toxic and harmful pollutants in the sludge will gradually penetrate into the surrounding environment after landfill, which is easy to pollute the soil and groundwater; (2) incineration, which can realize the harmless and reduction of sludge at high temperature, and completely kill a large amount of organic pollutants in the sludge, but the sludge has a high water content and a very low calorific value, which cannot sustain combustion, and part of the volatile heavy metals will further enter the gas state to form fly ash, causing secondary pollution; (3) pyrolysis gasification, which refers to the conversion of sludge into gas, liquid and solid three-phase products under anoxic inert atmosphere and relatively mild reaction temperature, a large amount of heavy metals will be retained in the solid phase, and the gas and liquid can be further treated and utilized, this method has low investment and is suitable for large-scale application, but there are problems of pyrolysis gasification tar and subsequent treatment of sludge coke. These methods cannot completely harmlessly treat sludge in the whole process, therefore, the sludge problem will become an important bottleneck restricting the urbanization process.

[0003] Cyclone melting technology is a high-temperature combustion technology, which has the advantages of complete harmless disposal of heavy metals and other pollutants, and the obtained molten slag has many advantages such as high stability, moderate operating cost, significant reduction and resource utilization. However, the inorganic components contained in the sludge are complex and have large fluctuation in melting point, it is difficult to completely melt and liquefy, the target setting of operating parameters is poor, and the design of the sludge melting furnace in the sludge is difficult; in addition, the cyclone melting requires a high combustion temperature higher than the melting point of inorganic matter, and the sludge has a low calorific value, which is difficult to achieve self-sustaining cyclone melting combustion temperature.

[0004] In view of this, the present application provides a rice husk assisted sludge pyrolysis gasification cyclone melting harmless disposal method and device, and its core innovation points are as follows: (1) the rice husk assisted sludge pyrolysis gasification improves the calorific value of the obtained gas product, and the high water content volatilization gas of the rice husk and the sludge in the baking process is used to reform the pyrolysis gas, further improving the quality of the gas product, so as to achieve the temperature required for subsequent cyclone melting combustion; (2) the high content of silicon dioxide in the rice husk can react with the sludge pyrolysis coke in the cyclone melting combustion process, forming a low-melting-point silicate, reducing the melting point of the sludge ash, and adjusting the proportion of the rice husk to adjust the temperature of the cyclone melting liquefaction, realizing the industrial design of the sludge melting furnace and the stable operation of the whole system. SUMMARY

[0005] The purpose of the present application is to provide a rice husk assisted sludge pyrolysis gasification cyclone melting harmless disposal method and device which is completely harmless and energy self-sufficient.

[0006] The present application is realized by the following technical solutions:

[0007] The method of rice husk assisted sludge pyrolysis gasification cyclone melting harmless disposal comprises the following steps:

[0008] The sludge and rice husk accessories are fed into the indirect heating jacketed roaster through the hoppers in a certain proportion, the reaction temperature is controlled at 200-300℃ for a certain time, preferably, the holding time is controlled at 1-3 hours. Under this condition, the sludge-rice husk mixed raw material is first preheated and dried to remove a large amount of external moisture, then the low-temperature pyrolysis reaction occurs in the roasting process to further remove the internal water and small molecule oxygen-containing components, so that the energy-containing components are enriched in the solid phase product, thus obtaining a high-energy density solid phase product. The solid phase product is fed into the vertical gasification furnace through the discharge port of the heating jacketed roaster and connected to the wind catcher. In the vertical gasification furnace, the solid phase product reacts with air to generate gasification reaction. The gasification reaction temperature is 600-800℃. The gasification residual coke is transported to the reformer through the grate at the bottom of the vertical gasification furnace and reacts with the gasification gas overflowing from the gas outlet of the vertical gasification furnace in the reformer to generate a catalytic reforming reaction. At the same time, the roasting gas produced in the roasting process of the sludge and rice husk (which contains a large amount of water vapor and carbon dioxide and other light components) is introduced into the reformer as a reforming medium to jointly undergo a series of reforming reactions (such as steam conversion reaction C+H2O→CO+H2, water gas shift reaction CO+H2O→CO2+H2, methane dry reforming reaction CH4+CO2→2CO+2H2, etc. steam reforming and carbon dioxide reforming reactions). The reforming process improves the quality of the gasification gas and increases the calorific value of the gasification gas. The gasification residual coke after catalytic reforming is discharged through the cold slag catcher and the wind catcher, enters the crusher for crushing, and the crushed coke powder is sprayed into the powder inlet of the cyclone smelting furnace and contacts with the high-temperature air fed from the hot air inlet of the cyclone smelting furnace to generate a combustion reaction. In addition, the combustion-supporting inlet of the cyclone smelting furnace is fed with the gasification gas after reforming to support combustion, and the ash contained in the gasification residual coke and the fly ash carried by the gasification gas are completely melted and liquefied, achieving the purpose of effectively solid-solubilizing heavy metals in the sludge.

[0009] Preferably, the combustion temperature in the cyclone smelting furnace is controlled at 1200-1400℃.

[0010] Preferably, the temperature of the high-temperature air fed from the hot air inlet of the cyclone smelting furnace is controlled at 400-600℃.

[0011] Preferably, in the vertical gasification furnace, the solid phase product reacts with a small amount of air, and the air injection amount of the small amount of air is obtained from the excess air coefficient of 0.1-0.3.

[0012] Preferably, the high-temperature flue gas discharged from the cyclone smelting furnace is preheated by the air-gas heat exchanger, then fed into the indirect heating jacketed roaster as a heat source, and the flue gas is discharged after being cooled; the air preheated by the air-gas heat exchanger is fed into the hot air inlet of the cyclone smelting furnace as high-temperature air to contact with the powder sprayed into the cyclone smelting furnace to generate a combustion reaction, realizing the energy self-sufficiency of the whole process.

[0013] As preferred, the rice husk auxiliary material is mainly composed of organic components (85%-90%) and silicon dioxide (SiO2, 10%-15%), and the feeding amount can be determined by the energy self-sufficiency demand and the cyclone melting temperature demand of the whole process, and is generally controlled within 10%-30% of the total weight of the mixture added in the indirect heating jacketed baker, the rice husk auxiliary sludge pyrolysis gasification can improve the calorific value of the obtained gas product, and the high water content volatile gas reforming pyrolysis gas in the baking process of the rice husk and the sludge can further improve the quality of the gas product, so as to reach the required temperature of the subsequent cyclone melting combustion; meanwhile, the high content of silicon dioxide in the rice husk can react with the sludge pyrolysis coke in the cyclone melting combustion process to form silicates with low melting points, so as to reduce the melting point of the sludge ash, and the proportion of the rice husk can be adjusted to adjust the temperature of the cyclone melting liquefaction, so as to realize the industrial design of the sludge melting furnace and the stable operation of the whole system.

[0014] On the basis of the method, the application further provides a device for rice husk auxiliary sludge pyrolysis gasification cyclone melting harmless treatment, which specifically comprises: a stock bin, an indirect heating jacketed baker, a wind catcher, a vertical gasification furnace, a grate, a reformer, a crusher, a cyclone melting furnace, a cold slag cooler, a gas-gas heat exchanger and a blower.

[0015] The outlets of the sludge stock bin and the rice husk stock bin are connected with the material inlet of the indirect heating jacketed baker, the discharge port of the baker is connected with the wind catcher, the outlet of the wind catcher is connected with the material inlet of the vertical gasification furnace, the bottom of the vertical gasification furnace is provided with a grate, the other side of the grate is connected with the reformer, the gas outlet of the vertical gasification furnace is connected with the reformer, the gasification residual coke outlet of the reformer is connected with the cold slag cooler, the cold slag cooler is connected with the wind catcher, the gasification residual coke discharged through the wind catcher enters the crusher, and the crusher is connected with the powder inlet of the cyclone melting furnace.

[0016] The high-calorific-value gasification gas in the reformer is connected with the combustion-supporting gas inlet of the cyclone melting furnace through the gasification gas outlet of the reformer, the liquid slag discharge port of the cyclone melting furnace discharges the liquid slag, the high-temperature flue gas outlet of the cyclone melting furnace is connected with the hot flue gas inlet of the gas-gas heat exchanger, the hot flue gas outlet of the gas-gas heat exchanger is connected with the hot medium inlet of the indirect heating jacketed baker, the high-temperature flue gas is discharged after heat exchange and cooling, the blower is connected with the air inlet of the gas-gas heat exchanger, the air is preheated by the hot flue gas to become high-temperature air, and the air outlet of the gas-gas heat exchanger is connected with the hot air inlet of the cyclone melting furnace.

[0017] Compared with the prior art, the present application has the following advantages: (1) the rice husk assisted sludge pyrolysis gasification improves the calorific value of the obtained gas product, and the high water content volatile gas in the rice husk and sludge in the baking process is used to reform the pyrolysis gas, further improving the quality of the gas product, so as to reach the required temperature of subsequent cyclone melting combustion; (2) the high content of silicon dioxide in the rice husk is used, which can react with the sludge pyrolysis coke in the cyclone melting combustion process to form a low melting point silicate, thereby reducing the melting point of the sludge ash, and by adjusting the proportion of the rice husk, the temperature of the cyclone melting liquefaction can be adjusted, so that the industrial design of the sludge melting furnace and the stable operation of the whole system are realized; (3) the whole system can systematize and self-heat to dispose of various sludge in a harmless way, and can realize energy self-sufficiency of the whole system and solid solution of heavy metals and other pollutants, so that they are completely harmless. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to facilitate the description, the present application is described in detail by the following specific embodiments and drawings.

[0019] Figure 1 The process and device diagram involved in the rice husk assisted sludge pyrolysis gasification cyclone melting harmless disposal method of the present application.

[0020] In the figure: 1 - material inlet of indirect heating jacketed baker; 2 - indirect heating jacketed baker; 3 - baker discharge port; 4 - gas outlet of indirect heating jacketed baker; 5 - air lock; 6 - vertical gasification furnace; 7 - grate; 8 - gas outlet of vertical gasification furnace; 9 - reformer; 10 - reformer reforming medium inlet; 11 - reformer gasification gas outlet; 12 - cold slag machine; 13 - air lock; 14 - crusher; 15 - cyclone melting furnace powder inlet; 16 - cyclone melting furnace combustion gas inlet; 17 - cyclone melting furnace; 18 - cyclone melting furnace liquid slag discharge port; 19 - cyclone melting furnace high temperature flue gas outlet; 20 - gas-gas heat exchanger; 21 - hot flue gas inlet of gas-gas heat exchanger; 22 - hot flue gas outlet of gas-gas heat exchanger; 23 - air outlet of gas-gas heat exchanger; 24 - air inlet of gas-gas heat exchanger; 25 - air blower; 26 - hot medium inlet of indirect heating jacketed baker; 27 - hot air inlet of cyclone melting furnace. EMBODIMENT

[0021] As Figure 1 shown, a device involved in a rice husk assisted sludge pyrolysis gasification cyclone melting harmless disposal method, comprising an indirect heating jacketed baker 2, air locks 5 and 13, a vertical gasification furnace 6, a grate 7, a reformer 9, a cold slag machine 12, a crusher 14, a cyclone melting furnace 17, a gas-gas heat exchanger 20, and an air blower 25.

[0022] The outlet of the sludge bunker and the rice husk bunker is connected to the material inlet 1 of the indirectly heated jacketed roaster, the outlet 3 of the roaster is connected to the deduster 5, the outlet of the deduster 5 is connected to the material inlet of the vertical gasifier 6, the bottom of the vertical gasifier is provided with the grate 7, the other side of the grate 7 is connected to the reformer 9, the gas outlet 8 of the vertical gasifier is connected to the reformer 9, the gas outlet 4 of the indirectly heated jacketed roaster is connected to the reformer medium inlet 10, the gasification residual coke outlet of the reformer 9 is connected to the slag cooler 12, the slag cooler 12 is connected to the deduster 13, the gasification residual coke discharged through the deduster 13 enters the crusher 14, the outlet of the crusher 14 is connected to the powder inlet 15 of the cyclone smelting furnace;

[0023] The high-calorific-value gasification gas after upgrading in the reformer 9 is connected to the combustion-supporting gas inlet 16 of the cyclone smelting furnace through the reformer gas outlet 11, the liquid slag is discharged through the liquid slag outlet 18 of the cyclone smelting furnace, the high-temperature flue gas outlet 19 of the cyclone smelting furnace is connected to the hot flue gas inlet 21 of the gas-gas heat exchanger, the hot flue gas outlet 22 of the gas-gas heat exchanger is connected to the hot medium inlet 26 of the indirectly heated jacketed roaster, and the heat-exchanged and cooled gas is discharged, the air inlet 24 of the gas-gas heat exchanger is connected to the air blower 25, the air blown in is preheated by the hot flue gas to become high-temperature air, and the air outlet 23 of the gas-gas heat exchanger is connected to the hot air inlet 27 of the cyclone smelting furnace.

[0024] A rice husk assisted sludge pyrolysis gasification cyclone melting harmless disposal method based on the above device, the specific steps are as follows: the rice husk and the sludge are fed into the indirect heating jacketed baker 2 through the respective hoppers according to a certain proportion, the rice husk and the sludge are mixed and heated in the baker 2, and after reaching the baking temperature interval (200-300℃), it is kept for 1-3 hours, after baking, the sludge no longer maintains the non-Newtonian fluid state, but forms a dry mixed form with the rice husk, the sludge-rice husk mixed raw material undergoes a low-temperature pyrolysis reaction during the baking process, the energy density of the solid phase product is increased, and the mixed raw material is fed into the vertical gasification furnace 6 through the discharge port connected to the damper 5, and the gasification reaction occurs in the gasification furnace 6, the gasification reaction temperature is 600-800℃, and the gasification residual coke is transported to the reformer 9 through the grate 7 at the bottom of the vertical gasification furnace, and the catalytic reforming reaction occurs with the gasification gas overflowing from the gas outlet, at the same time, the baking gas (which contains a large amount of water vapor and carbon dioxide and other light components) generated during the baking process of the sludge and the rice husk is used as the reforming medium, the reforming process improves the quality of the gasification gas and increases the calorific value of the gasification gas; the gasification residual coke after catalytic reforming is discharged through the cold slag remover 12 and the damper 13, enters the crusher 14 for crushing, and the crushed coke powder is sprayed into the cyclone melting furnace powder inlet 15 of the cyclone melting furnace 17, and contacts with the high-temperature air with a temperature of 400-600℃ at the cyclone melting furnace hot air inlet to occur a combustion reaction, in addition, the gasification gas after quality improvement is fed into the combustion-supporting inlet of the cyclone melting furnace 17 for combustion-supporting, the combustion temperature is controlled to reach 1200-1400℃, the ash contained in the gasification residual coke and the fly ash carried by the gasification gas are completely melted and liquefied, and the purpose of effectively solid-solubilizing the heavy metals in the sludge is achieved. The high-temperature flue gas discharged from the cyclone melting furnace 17 is used to preheat the air after the air-gas heat exchanger 20, in order to promote the cyclone melting combustion, the preheated air temperature is set to 400-600℃ so as to be fed into the cyclone melting furnace as high-temperature air in the subsequent process, and the flue gas is fed into the indirect heating jacketed baker as a heat source after heat exchange by the air-gas heat exchanger, and the flue gas is discharged after cooling, so that the whole process realizes energy self-sufficiency.

[0025] The rice husk assisted sludge pyrolysis gasification cyclone melting harmless disposal method of the present application, wherein the feeding amount of the rice husk auxiliary material is controlled within the range of 10%-30% according to the energy self-sufficiency demand and the cyclone melting temperature demand of the whole process, the rice husk assisted sludge pyrolysis gasification can improve the calorific value of the obtained gas product, and the high-moisture volatile gas in the baking process of the rice husk and the sludge is used for reforming and pyrolysis of the gasification gas, further improving the quality of the gas product to achieve the required temperature of the subsequent cyclone melting combustion; at the same time, the high content of silicon dioxide in the rice husk can occur ash phase high-temperature reaction with the sludge pyrolysis coke in the process of cyclone melting combustion, forming a low-melting-point silicate to reduce the melting point of the sludge ash, and the proportion of the rice husk can be adjusted to adjust the temperature of the cyclone melting liquefaction, realizing the industrial design of the sludge melting furnace and the stable operation of the whole system.

[0026] Specifically, the comparison data of the method used in the present application and the melting point of the sludge ash obtained by the rice husk assisted pyrolysis gasification cyclone melting are as follows: The sludge is municipal sludge, which is high-temperature calcined, and when the test temperature reaches 1300 DEG C, the sludge ash has not yet softened obviously, because the content of Ca and P elements in the measured sludge ash is relatively high, which will form calcium phosphate salt with high melting point at high temperature, resulting in difficult liquid slagging of sludge alone pyrolysis gasification cyclone melting; while the test adopts 15% rice husk assisted pyrolysis gasification cyclone melting, it is found that the mixed gasification residual coke is obviously softened when the calcination temperature reaches 1150 DEG C, and the analysis is that the high content of silicon dioxide and a small amount of K element in the rice husk exist, and the low melting point silicate is formed in the ashing process, so that the system can realize the liquid slagging, and achieve the effect of completely solid-solution of heavy metals in the sludge. Therefore, it is proved that the method of the present application is practical and the effect is remarkable.

[0027] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for rice husk assisted sludge pyrolysis gasification cyclonic melting innocuous disposal, characterized in that, The method comprises the following steps: The sludge and rice husk accessories are respectively fed into the indirect heating jacketed roaster through the silos in a certain proportion, the reaction temperature is controlled at 200-300 ℃ for a certain time, the sludge-rice husk mixed raw materials undergo low-temperature pyrolysis reaction to form solid phase products during the roasting process, then the solid phase products are fed into the vertical gasification furnace through the discharge port of the heating jacketed roaster and the wind catcher, and the gasification reaction occurs in the vertical gasification furnace, the gasification reaction temperature is 600-800 ℃, the gasification residue formed by the gasification is transported to the reformer through the grate at the bottom of the vertical gasification furnace, and the catalytic reforming reaction occurs in the reformer between the gasification residue and the gasification gas overflowing from the gas outlet of the vertical gasification furnace, at the same time, the roasting gas generated during the roasting process of the sludge and rice husk is introduced into the reformer as the reforming medium to improve the quality of the gasification gas and increase the calorific value of the gasification gas during the reforming process; the gasification residue after the catalytic reforming is discharged through the cold slag device and the wind catcher, enters the crusher for crushing, and the crushed coke powder is sprayed into the powder inlet of the cyclone smelting furnace, contacts with the high-temperature air introduced from the hot air inlet of the cyclone smelting furnace, and the combustion reaction occurs, in addition, the combustion-supporting gas after the quality improvement of the reforming is introduced into the combustion-supporting inlet of the cyclone smelting furnace, the ash contained in the gasification residue and the fly ash carried by the gasification gas are completely melted and liquefied, and the purpose of effectively solid-solubilizing the heavy metals in the sludge is achieved.

2. The method of rice husk assisted sludge pyrolysis gasification cyclone melt innocuous disposal according to claim 1, characterized in that, The high-temperature flue gas discharged from the cyclone smelting furnace is used to preheat the air through the gas-gas heat exchanger, and then is introduced into the indirect heating jacketed roaster as a heat source, and the flue gas is discharged after being cooled; The air preheated through the gas-gas heat exchanger is used as high-temperature air and introduced into the hot air inlet of the cyclone smelting furnace to contact with the powder sprayed into the cyclone smelting furnace to realize the combustion reaction and achieve the energy self-sufficiency of the whole process.

3. The method of rice husk assisted sludge pyrolysis gasification cyclonic melt-inertial innocuous disposal of claim 1, wherein, The introduction amount of the rice husk accessories is determined according to the energy self-sufficiency demand and the cyclone smelting temperature demand of the whole process, and the introduction amount is controlled to be 10%-30% of the total weight of the mixture introduced into the indirect heating jacketed roaster.

4. The method of rice husk assisted sludge pyrolysis gasification cyclonic melt-inertial innocuous disposal of claim 1, wherein, The reaction temperature of the sludge and rice husk accessories in the indirect heating jacketed roaster is controlled at 200-300 ℃ for 1-3 hours.

5. The method of rice husk assisted sludge pyrolysis gasification cyclonic melt-inertial innocuous disposal of claim 1, wherein, The combustion temperature in the cyclone smelting furnace is controlled at 1200-1400 ℃.

6. The method of rice husk assisted sludge pyrolysis gasification cyclonic melt-inertial innocuous disposal of claim 1, wherein, The temperature of the high-temperature air introduced from the hot air inlet of the cyclone smelting furnace is controlled at 400-600 ℃.

7. An apparatus for implementing the method of any one of claims 1 to 6, characterized in that Specifically comprises: The silos, the indirect heating jacketed roaster, the wind catcher, the vertical gasification furnace, the grate, the reformer, the crusher, the cyclone smelting furnace, the cold slag device, the gas-gas heat exchanger and the air blower; The outlets of the sludge silo and the rice husk silo are connected with the material inlets of the indirect heating jacketed roaster, the discharge port of the indirect heating jacketed roaster is connected with the wind catcher, the outlet of the wind catcher is connected with the material inlet of the vertical gasification furnace, the bottom of the vertical gasification furnace is provided with the grate, the other side of the grate is connected with the reformer, the gas outlet of the vertical gasification furnace is connected with the reformer, the gas outlet of the indirect heating jacketed roaster is connected with the reforming medium inlet of the reformer, the gasification residue outlet of the reformer is connected with the cold slag device, the cold slag device is connected with the wind catcher, the gasification residue discharged through the wind catcher enters the crusher, and the crusher is connected with the powder inlet of the cyclone smelting furnace. The high-calorific-value gasification gas after upgrading in the reformer is connected to the combustion-supporting gas inlet of the cyclone smelting furnace via the reformer gasification gas outlet, the liquid slag is discharged from the liquid slag outlet of the cyclone smelting furnace, the high-temperature flue gas outlet of the cyclone smelting furnace is connected to the hot flue gas inlet of the gas-gas heat exchanger, the hot flue gas outlet of the gas-gas heat exchanger is connected to the hot medium inlet of the indirectly-heated jacketed roaster, and the high-temperature flue gas is discharged after heat exchange and cooling; the air inlet of the gas-gas heat exchanger is connected to the air blower, the air is preheated by the hot flue gas to become high-temperature air, and the air outlet of the gas-gas heat exchanger is connected to the hot air inlet of the cyclone smelting furnace.

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