Heat treatment furnace set and system for spent activated carbon regeneration

Abstract

The application relates to a heat treatment furnace group and system for waste activated carbon regeneration. The heat treatment furnace group for waste activated carbon regeneration comprises a pyrolysis desorption furnace, an activation regeneration furnace and a guide pipeline. The pyrolysis desorption furnace is provided with a first heating component for heating the pyrolysis desorption furnace and a pyrolysis gas outlet for guiding out pyrolysis desorption gas. The activation regeneration furnace is separately arranged from the pyrolysis desorption furnace and is provided with a second heating component for heating the activation regeneration furnace and an activation gas inlet for guiding activation gas into the activation regeneration furnace. The guide pipeline is located between the discharge end of the pyrolysis desorption furnace and the feeding end of the activation regeneration furnace. The waste activated carbon can be heated in the guide pipeline and the pyrolysis desorption furnace by the activation gas with high temperature, the selection of the two furnace bodies and the adjustment of the hot flue gas inlet and outlet position of the flue gas cavity are supplementary, which is beneficial to fully pyrolyzing and activating the waste activated carbon and simultaneously improves the utilization efficiency of heat energy.

Description

Technical Field

[0001] This application relates to the technical field of activated carbon regeneration (C01B32 / 36), specifically to a heat treatment furnace and system for the regeneration of waste activated carbon. Background Technology

[0002] Waste activated carbon is a hazardous waste generated during industrial adsorption processes, primarily from industries such as water treatment, chemicals, pharmaceuticals, and food processing. Once saturated, it contains pollutants such as organic matter and heavy metals, and is classified as hazardous waste (HW49). Data shows that my country produces millions of tons of waste activated carbon annually, making its activation and regeneration practically significant.

[0003] Thermal regeneration is a mainstream method for regenerating activated carbon. Through two steps—anaerobic pyrolysis and steam activation—the adsorption recovery rate reaches over 90%. In existing technologies, the anaerobic pyrolysis and steam activation steps are generally completed within the same furnace. For example, Chinese patent document CN116371390A discloses a method for the carbonization and regeneration of waste activated carbon, which involves placing the waste activated carbon in an activation furnace for sequential drying, carbonization, and activation. During the drying process, the water adsorbed by the waste activated carbon is evaporated by heating, resulting in dry activated carbon. The carbonization process is carried out in a slightly oxygen-enriched atmosphere, where some organic matter undergoes chemical bond breakage at high temperatures, and the volatiles released by thermal desorption combine with oxygen, undergoing an oxidation reaction; some organic matter is carbonized at high temperatures and adsorbed into the pores of the activated carbon. During the activation process, the remaining organic matter undergoes an activation reaction with the introduced steam at even higher temperatures, restoring the original pore openness of the activated carbon, increasing its specific surface area, and achieving the purpose of regenerating waste activated carbon. The high-temperature in-situ thermal pyrolysis, activation and regeneration treatment equipment for waste activated carbon disclosed in Chinese patent document CN214051672U, or the waste activated carbon regeneration system disclosed in Chinese patent document CN212595752U, both involve thermal pyrolysis and activation being completed in the same furnace.

[0004] Since the activation temperature of steam is generally 200-300℃ higher than that of anaerobic pyrolysis, the furnace operates at a relatively high temperature without adjusting the heating temperature, resulting in ineffective heat utilization. Furthermore, adjusting the heating temperature requires a certain reaction time, leading to fluctuations in the treatment effect. Summary of the Invention

[0005] The primary objective of this invention is to overcome the shortcomings of existing technologies and provide a heat treatment furnace group for the regeneration of waste activated carbon, which allows desorption pyrolysis and steam activation to be carried out in different furnace bodies, thereby improving the heat treatment efficiency of waste activated carbon while achieving personalized control of heating temperature.

[0006] To achieve the above objectives, the technical solution of this application is as follows: Heat treatment furnace units for the regeneration of waste activated carbon, including The thermal desorption furnace desorbs adsorbates existing in the pores of activated carbon and decomposes organic matter. It has a first heating element for heating the thermal desorption furnace and a thermal desorption gas outlet for discharging the thermal desorption gas. The activation and regeneration furnace is set separately from the thermal decomposition furnace, and has a second heating element for heating the activation and regeneration furnace and an activation gas inlet for introducing activation gas into the activation and regeneration furnace. The guide pipeline is located between the discharge end of the thermal desorption furnace and the feed end of the activation and regeneration furnace. It is used to guide the waste activated carbon in the thermal desorption furnace to the activation and regeneration furnace and to introduce the activation gas generated in the activation and regeneration furnace into the thermal desorption furnace, and then discharge it from the thermal desorption gas outlet along with the thermal desorption gas in the thermal desorption furnace.

[0007] The inventive concept of this invention lies in modifying the previous method of conducting desorption and pyrolysis of waste activated carbon within the same furnace. Instead, thermal pyrolysis and activation are carried out in separate furnaces, allowing for independent control of the waste activated carbon's propulsion speed and heat treatment temperature within each furnace. Furthermore, as is common knowledge, the heating temperature of an activation regeneration furnace is around 800-1000℃, while that of a thermal desorption furnace is around 500-600℃. The activation gas generated in the activation regeneration furnace, with a high temperature of around 500℃, can internally heat the waste activated carbon in the thermal desorption furnace, thereby improving the thermal desorption efficiency. Secondly, the collision between the higher-temperature activation gas and the activated carbon in the guide pipes promotes thorough pyrolysis of the activated carbon. This combination of techniques allows for precise control of the two processes in the regeneration of waste activated carbon, achieving more efficient energy utilization while ensuring complete treatment.

[0008] As an improvement, the first heating element is a flue gas duct located on the outer layer of the pyrolysis desorption furnace, with a heated flue gas inlet and a heated flue gas outlet; the second heating element is a burner, allowing the pyrolysis desorption furnace and the activation regeneration furnace to have relatively independent heating sources. While the pyrolysis desorption furnace is internally heated by activating gas, external heating with hot flue gas is used simultaneously, which helps improve the pyrolysis desorption efficiency. The activation regeneration furnace directly generates a high temperature of approximately 1000°C by injecting the gas directly into the furnace body through the burner.

[0009] As a further improvement, the heating flue gas inlet and outlet are located at the feed end and discharge end of the pyrolysis furnace, respectively, and the pyrolysis gas outlet is located at the feed end of the pyrolysis furnace, so that the flow direction of the heating flue gas is opposite to the flow direction of the activation gas inside the pyrolysis furnace. This scheme is beneficial for the waste activated carbon to undergo pyrolysis at a relatively uniform temperature.

[0010] As an improvement, a thermocouple is installed at each end of the flue gas duct to monitor the flue gas temperature at both ends. The thermocouples are used to monitor whether the temperature of the flue gas duct is within a set range. When the temperature difference between the two ends is too large, there may be relatively severe coking within the flue gas duct, requiring a furnace shutdown.

[0011] As an improvement, the thermal desorption furnace is a spiral propulsion furnace, and the activation and regeneration furnace is a converter. The activation and regeneration furnace has a guide section at one end for connecting the guide pipeline. During the rotation of the converter, the internal lifting plates can fully achieve contact between the waste activated carbon and the activation gas, which is beneficial to improving the processing efficiency.

[0012] As an improvement, the heat desorption furnace and the activation regeneration furnace are arranged vertically, and the guide pipes are vertical pipes or inclined chutes.

[0013] As an improvement, a cooling furnace body is also included, connected to the discharge end of the activation and regeneration furnace, for cooling the activated waste activated carbon.

[0014] Another objective of this application is to provide a system for the regeneration of spent activated carbon, achieving efficient pyrolysis of the spent activated carbon, comprising a heat treatment furnace and auxiliary facilities. The auxiliary facilities include a recombustion chamber for combustion treatment of gases discharged from the pyrolysis gas outlet, a waste heat boiler for providing activation steam to the activation regeneration furnace, and a tail gas treatment unit for treating the heated flue gas. The recombustion chamber is sequentially connected to the pyrolysis desorption furnace, the waste heat boiler, and the tail gas treatment unit.

[0015] As an improvement, the exhaust gas treatment unit includes, in sequence, a quench tower, a dry reactor, a bag filter, a spray scrubbing tower, and a chimney.

[0016] The beneficial effects of this utility model are as follows: by pyrolyzing and activating the waste activated carbon in different furnaces, the propulsion speed and heat treatment temperature of the waste activated carbon in the two furnaces can be controlled independently. The activation gas at a higher temperature can also heat the waste activated carbon in the guide pipeline and the pyrolysis desorption furnace. With the selection of two furnaces and the adjustment of the hot flue gas inlet and outlet positions of the flue gas cavity, it is beneficial to fully pyrolyze and activate the waste activated carbon, while improving the utilization efficiency of thermal energy. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model; Figure 2 This is a schematic diagram of the thermal decomposition furnace in Embodiment 1 of this utility model; Figure 3This is a schematic diagram of the structure of Embodiment 2 of the present invention. The paths of pyrolysis gas and activation steam are represented by dashed lines, and the paths of heating flue gas and its tail gas are represented by solid lines. Figure 4 This is a schematic diagram of the structure of Embodiment 3 of this utility model.

[0018] In the diagram: 10. Pyrolysis desorption furnace; 11. First heating element; 111. Heating flue gas inlet; 112. Heating flue gas outlet; 113. Thermocouple; 12. Pyrolysis gas outlet; 20. Activation and regeneration furnace; 21. Second heating element; 22. Activation gas inlet; 23. Guide section; 30. Guide pipeline; 40. Cooling furnace body; 50. Recombustion chamber; 60. Waste heat boiler; 71. Quenching tower; 72. Dry reactor; 73. Bag filter; 74. Spray scrubbing tower; 75. Chimney; 81. Feed silo; 82. Elevator; 83. Feed scraper conveyor; 91. Conveying scraper conveyor; 92. Finished product silo. Detailed Implementation

[0019] The present application will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present application. Furthermore, it should be understood that after reading the teachings of this application, those skilled in the art can make various alterations or modifications, and these equivalent forms also fall within the scope of protection defined by the appended claims. Example 1

[0020] The heat treatment furnace group for regenerating waste activated carbon described in this invention includes a heat desorption furnace 10 and an activation regeneration furnace 20, which are connected in sequence and arranged separately. The purpose of the heat desorption furnace 10 is to desorb the adsorbents present in the pores of the activated carbon and to decompose the organic matter. The purpose of the activation regeneration furnace 20 is to activate the remaining organic matter with the introduced water vapor at a higher temperature, thereby restoring the activated carbon to a state of open pores.

[0021] like Figure 1 , Figure 2As shown, the thermal desorption furnace 10 is a spiral propulsion furnace with an internal shaftless spiral. Stirring rods are placed between adjacent spiral blades, which facilitates the turning of the waste activated carbon from the bottom to the top as the shaftless spiral rotates. The activation and regeneration furnace 20 is a converter. Converter structures are common, with lifting plates on the inner wall to facilitate material dispersion, and mechanisms driving its rotation on the outer wall or at both ends. The thermal desorption furnace 10 and the activation and regeneration furnace 20 are arranged vertically and have independent drive structures, allowing independent control of the residence time of the waste activated carbon. Furthermore, the thermal desorption furnace 10 and the activation and regeneration furnace 20 have relatively independent heating sources, allowing independent control of the heating temperature of the two furnaces. The heating source of the thermal desorption furnace 10, i.e., the first heating element 11, is a flue gas duct located on the outer layer of the thermal desorption furnace 10, supplied with high-temperature flue gas by the recombustion chamber 50. The heating source of the activation and regeneration furnace 20, i.e., the second heating element 21, is a burner. One end of the activation and regeneration furnace 20 is provided with an activation gas inlet 22 for introducing activation gas into the activation and regeneration furnace 20.

[0022] A vertically arranged guide pipe 30 is provided between the discharge end of the pyrolysis furnace 10 and the feed end of the activation and regeneration furnace 20. The activation and regeneration furnace 20 has a guide section 23 at one end for connecting to the guide pipe 30, and a horizontally arranged pushing spiral is provided within the guide section 23. The activation gas generated by the activation and regeneration furnace 20 enters the pyrolysis furnace 10 via the guide pipe 30, and then, along with the pyrolysis gas from the pyrolysis furnace 10, is discharged from the pyrolysis gas outlet 12 to the re-combustion chamber 50 for combustion. The combustion temperature is 1100℃, and the combustion time is greater than 2 seconds. The pyrolysis gas outlet 12 of the pyrolysis furnace 10 is located at the feed end of the pyrolysis furnace 10. The first heating component 11 has a heating flue gas inlet 111 and a heating flue gas outlet 112, which are located at the feed end and discharge end of the pyrolysis furnace 10, respectively, so that the flow direction of the heating flue gas is opposite to the flow direction of the activation gas inside the pyrolysis furnace 10. A thermocouple 113 is installed at each end of the flue gas duct to monitor the flue gas temperature at both ends of the flue gas duct. Example 2

[0023] like Figure 3 As shown, this embodiment is a system for the regeneration of waste activated carbon, including a heat treatment furnace and auxiliary facilities. The heat treatment furnace adopts the heat treatment furnace group described in Embodiment 1.

[0024] The ancillary facilities consist of three main components: The first is the gas-related auxiliary equipment. This mainly includes a recombustion chamber 50 for combustion treatment of the gas discharged from the pyrolysis gas outlet 12, a waste heat boiler 60 for providing activation steam to the activation regeneration furnace 20, and a tail gas treatment unit for treating the heated flue gas. The recombustion chamber 50 is sequentially connected to the pyrolysis desorption furnace 10, the waste heat boiler 60, and the tail gas treatment unit. The tail gas treatment unit sequentially includes a quench tower 71, a dry reactor 72, a bag filter 73, a spray scrubbing tower 74, and a chimney 75. The flue gas is rapidly cooled to 200°C in the quench tower 71, then enters the dry reactor 72 for purification, then the bag filter 73 for dust removal, and finally the spray scrubbing tower 74 for spray scrubbing before being discharged through the chimney 75.

[0025] Second, the auxiliary facilities related to activated carbon feeding include a feed silo 81, an elevator 82, and a feed scraper 83. The feed scraper 83 scrapes the waste activated carbon lifted by the elevator 82 into the feed inlet of the pyrolysis furnace 10.

[0026] Thirdly, the auxiliary facilities related to activated carbon discharge mainly include a cooling furnace body 40, which is located at the discharge end of the activation and regeneration furnace 20 and is used to cool the activated carbon after activation, generally by water cooling. The cooled activated carbon is conveyed to the finished product silo 92 by a conveying scraper conveyor 91. The cooling furnace body 40 can be a slag cooler as used in existing technology. Example 3

[0027] like Figure 4 As shown, the difference between this embodiment and Embodiment 1 is that: Both the thermal desorption furnace 10 and the activation and regeneration furnace 20 are converters, and the guide pipe 30 is an inclined chute. Obviously, the thermal desorption furnace 10 and the activation and regeneration furnace 20 can also be heated electrically.

Claims

1. A heat treatment furnace unit for the regeneration of waste activated carbon, characterized in that: include The thermal desorption furnace (10) desorbs adsorbents present in the pores of activated carbon and decomposes organic matter. It has a first heating element (11) for heating the thermal desorption furnace (10) and a pyrolysis gas outlet (12) for discharging the thermal desorption gas. The activation regeneration furnace (20) is set separately from the heat desorption auxiliary furnace (10), and has a second heating element (21) for heating the activation regeneration furnace (20) and an activation gas inlet (22) for introducing activation gas into the activation regeneration furnace (20). The guide pipe (30) is located between the discharge end of the thermal desorption furnace (10) and the feed end of the activation and regeneration furnace (20). It is used to guide the waste activated carbon in the thermal desorption furnace (10) to the activation and regeneration furnace (20) and to introduce the activation gas generated in the activation and regeneration furnace (20) into the thermal desorption furnace (10) and then discharge it from the thermal desorption gas outlet (12) along with the thermal desorption gas of the thermal desorption furnace (10).

2. The heat treatment furnace assembly for regenerating waste activated carbon as described in claim 1, characterized in that: The first heating element (11) is a flue gas duct located on the outer layer of the thermal decomposition furnace (10), and the flue gas duct has a heated flue gas inlet (111) and a heated flue gas outlet (112); the second heating element (21) is a burner, so that the thermal decomposition furnace (10) and the activation regeneration furnace (20) have relatively independent heating sources.

3. The heat treatment furnace assembly for regenerating waste activated carbon as described in claim 2, characterized in that: The heating flue gas inlet (111) and heating flue gas outlet (112) are located at the feed end and discharge end of the pyrolysis furnace (10), respectively, and the pyrolysis gas outlet (12) is located at the feed end of the pyrolysis furnace (10), so that the flow direction of the heating flue gas is opposite to the flow direction of the activation gas inside the pyrolysis furnace (10).

4. The heat treatment furnace assembly for regenerating waste activated carbon as described in claim 2, characterized in that: The flue gas cavity is equipped with a thermocouple (113) at each end for monitoring the flue gas temperature at both ends of the flue gas cavity.

5. The heat treatment furnace assembly for regenerating waste activated carbon as described in claim 1, characterized in that: The heat desorption furnace (10) is a spiral propulsion furnace, and the activation and regeneration furnace (20) is a converter. The activation and regeneration furnace (20) has a guide section (23) at one end for connecting the guide pipe (30).

6. The heat treatment furnace assembly for regenerating waste activated carbon as described in claim 5, characterized in that: The heat desorption furnace (10) and the activation and regeneration furnace (20) are arranged vertically, and the guide pipe (30) is a vertical pipe or an inclined chute.

7. The heat treatment furnace assembly for regenerating waste activated carbon as described in claim 1, characterized in that: It also includes a cooling furnace body (40), which is connected to the discharge end of the activation and regeneration furnace (20) and is used to cool the activated waste activated carbon.

8. A system for regenerating spent activated carbon, including a heat treatment furnace and auxiliary facilities, characterized in that: The heat treatment furnace is the heat treatment furnace group as described in claim 1.

9. The system for regenerating spent activated carbon as described in claim 8, characterized in that: The auxiliary facilities include a reburning chamber (50) for combustion treatment of the gas discharged from the pyrolysis gas outlet (12), a waste heat boiler (60) for generating activated steam, and a tail gas treatment unit for treating the heated flue gas tail gas. The reburning chamber (50) is connected in sequence to the pyrolysis auxiliary furnace (10), the waste heat boiler (60), and the tail gas treatment unit.

10. The system for regenerating spent activated carbon as described in claim 9, characterized in that: The exhaust gas treatment unit includes, in sequence, a quench tower (71), a dry reactor (72), a bag filter (73), a spray scrubbing tower (74), and a chimney (75).

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