Biomass carbonization and activation system and method coupled with circulating fluidized bed

Abstract

The invention provides a biomass carbonization and activation system and method coupled with a circulating fluidized bed, and belongs to the technical field of biomass gas-carbon co-production. The activation system comprises a circulating fluidized bed device and an activation device. The activating device is positioned at the downstream of the circulating fluidized bed device and comprises at least one first activating tank and at least one second activating tank; a solid material inlet and a feed valve are arranged at the top of each activation tank, a steam inlet and a steam inlet valve are arranged on the side wall of the bottom of each activation tank, an activated gas discharge outlet and an activated gas outlet valve are arranged on the side wall of the top of each activation tank, and an activated carbon outlet, an activated carbon outlet valve, a return material outlet and a return material valve are arranged at the bottom of each activation tank; at least one first activation tank activates second biomass charcoal by using superheated steam, a material returning outlet of at least one second activation tank is connected with a material returning opening of a dense-phase area of the circulating fluidized bed carbonization furnace through a pipeline, and simultaneous and alternate material returning and activation are realized by controlling all valves of the first activation tanks and the second activation tanks.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass gas-char cogeneration, and in particular relates to a biomass carbonization activation system coupled with a circulating fluidized bed and a biomass carbonization activation method. Background Art

[0002] Most biomass-gas-char cogeneration technologies utilize a fixed bed as a carbonization furnace and a rotary kiln as an activation furnace to produce biochar and activated carbon. Fixed-bed carbonization furnaces suffer from uneven heat distribution and difficult-to-handle high tar volumes, resulting in lower quality biochar and activated carbon, shorter production cycles, and poor environmental performance. Furthermore, rotary kilns as activation furnaces also present significant challenges, such as large equipment footprint, complex structure, uneven material heating, and complex integration with the fixed bed, further complicating the process.

[0003] Fluidized bed reactors are used in research on biomass-to-gas-to-charcoal cogeneration technology due to their excellent heat and mass transfer, flexible operation, and ease of large-scale expansion. However, due to the continuous feeding, short residence time within the fluidized bed, and high reaction intensity, the resulting biochar does not have sufficient activation time, resulting in low-quality activated carbon. Summary of the Invention

[0004] To address the above technical issues, the present invention provides a biomass carbonization activation system and method coupled with a circulating fluidized bed, in order to at least partially resolve the above technical issues. The technical solutions provided by the present invention are as follows.

[0005] In the first aspect of the present invention, a biomass carbonization activation system coupled with a circulating fluidized bed is provided, comprising: a circulating fluidized bed device, comprising a circulating fluidized bed carbonization furnace, the circulating fluidized bed carbonization furnace being suitable for converting biomass raw materials into a first biomass char and a mixed material comprising a first combustible gas and a second biomass char through a carbonization reaction; an activation device, located downstream of the circulating fluidized bed device, comprising at least one first activation tank and at least one second activation tank arranged in parallel, and each activation tank having a solid material inlet and a feed valve for the second biomass char to enter at the top, and a solid material inlet and a feed valve for the second biomass char to enter at the bottom side wall, and a solid material inlet for the superheated steam to enter at the bottom side wall. A steam inlet and a steam inlet valve for activating the second biomass charcoal, an activation gas discharge port and an activation gas outlet valve for discharging the first activation gas generated by activating the second biomass charcoal are arranged on the top side wall, an activated carbon outlet and an activated carbon outlet valve are arranged at the bottom, as well as a return material outlet and a return material valve; wherein at least one first activation tank utilizes superheated steam to activate the second biomass charcoal, and the return material outlet of at least one second activation tank is connected to the return material port of the dense phase zone of the circulating fluidized bed carbonization furnace through a pipeline, and the simultaneous return material and activation are achieved by controlling the respective valves of the first activation tank and the second activation tank, as well as the alternating execution of return material and activation.

[0006] As a second aspect of the present invention, a biomass carbonization activation method coupled with a circulating fluidized bed is provided, which is performed by the above-mentioned biomass carbonization activation system. The biomass carbonization activation method includes: in a circulating fluidized bed carbonization furnace, the biomass raw material undergoes a carbonization reaction to produce a first biomass charcoal and a mixture containing a first combustible gas and a second biomass charcoal; the second biomass charcoal enters the first activation tank and the second activation tank of the activation device for return and activation, including: controlling the various valves on the first activation tank, so that part of the second biomass charcoal enters at least one first activation tank and is activated by superheated steam to produce activated carbon and a first activation gas; at the same time, controlling the various valves on the second activation tank, so that part of the second biomass charcoal is returned to the circulating fluidized bed carbonization furnace through at least one second activation tank, controlling the various valves on the first activation tank and the second activation tank to achieve simultaneous return and activation, and alternately performing activation and return; wherein, the activation time is 1-3 hours.

[0007] Based on the above technical solution, the biomass carbonization activation system and method coupled with a circulating fluidized bed provided by the present invention have at least one of the following beneficial effects:

[0008] (1) The present invention provides a biomass carbonization activation system coupled with a circulating fluidized bed, with a specially designed activation tank. The activation device includes at least one first activation tank and at least one second activation tank arranged in parallel. By controlling the valves of the first activation tank and the second activation tank, simultaneous material return and activation, as well as alternating material return and activation, are achieved. This activation system solves the problems of traditional activation furnaces, such as heavy equipment, large floor space, and high energy consumption; it also solves the problem of low quality activated carbon caused by short activation time in a fluidized bed carbonization furnace, and can produce high-value-added activated carbon.

[0009] (2) The present invention provides a biomass carbonization activation method coupled with a circulating fluidized bed. By controlling the working progress of different activation tanks and coordinating the opening and closing of the valves of the activation tanks, at least one first activation tank activates the biomass charcoal while at least one second activation tank returns the material, thereby achieving simultaneous activation and return processes, ensuring the continuous and sustained carbonization and activation processes, and improving the working efficiency of the circulating fluidized bed carbonization furnace and the activation tank device. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Schematic diagram of the structure of a biomass carbonization and activation system coupled with a circulating fluidized bed in an embodiment of the present invention;

[0011] Figure 2 This is a schematic structural diagram of an activation tank in an embodiment of the present invention;

[0012] Figure 3 This is a flow chart of a biomass carbonization activation method coupled with a circulating fluidized bed in an embodiment of the present invention;

[0013] Figure 4 This is a schematic diagram of the process of alternately performing activation and material return in the activation tank in an embodiment of the present invention.

[0014] [Description of Reference Numerals]

[0015] 1-circulating fluidized bed carbonization furnace, 11-return material port, 12-mixed material outlet, 13-carbon discharge port, 14-carrier port;

[0016] 2-Biocal cooler;

[0017] 3-gas-solid separator, 31-mixed material inlet, 32-exhaust port, 33-solid material outlet;

[0018] 4-activation device, 4a-first activation tank, 4b-second activation tank, 41-solid material inlet, 411-feed valve, 42-steam inlet, 421-steam inlet valve, 43-activated gas discharge port, 431-activated gas outlet valve, 44-activated carbon outlet, 441-activated carbon outlet valve, 45-return material outlet, 451-return material valve, 401-housing, 402-fluidizing plate, 403-guide tube, 404-agitator;

[0019] 5-Activated carbon cooler;

[0020] 6-evaporator, 61-water inlet, 62-combustible gas inlet, 63-combustible gas outlet, 64-first discharge port, 65-second discharge port;

[0021] 7-steam superheater, 71-activated gas inlet, 72-steam inlet, 73-activated gas outlet, 74-steam outlet;

[0022] 8- activated gas cooler, 81- heat source inlet, 82- cold source inlet, 83- heat source outlet, 84- cold source outlet;

[0023] 9- Combustible gas storage tank;

[0024] A-biomass raw material, B-first biochar, C-first combustible gas, D-second biochar, E-mixed material, F-superheated steam, G-first activated gas, H-heat carrier, I-deoxygenated water, J-second combustible gas, K-first steam, L-second activated gas, M-activated carbon, N-water, O-third activated gas. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0026] The circulating fluidized bed reactor solves the problems of uneven heat distribution in the fixed bed and large amounts of tar that are difficult to handle. However, due to its own characteristics of requiring continuous material return, there is also the problem of insufficient biochar activation time and low quality of the activated carbon produced. In this regard, the present invention provides an activation system coupled with a circulating fluidized bed. By setting an activation device consisting of a plurality of activation tanks, and controlling the opening and closing of each valve on the activation tank, the material level in the activation tank is controlled, ensuring that while some activation tanks are performing activation work, the other part of the activation tanks return material to the circulating fluidized bed carbonization furnace to maintain stable operation of the circulating fluidized bed carbonization furnace and continuous biomass carbonization, the problem of poor quality of activated carbon due to short activation time of circulating fluidized bed biochar is solved, and the problem of inability of the circulating fluidized bed carbonization furnace to continuously return material due to long activation time is solved, thereby improving the working efficiency of the circulating fluidized bed carbonization furnace and the activation device.

[0027] Specifically, as a first aspect of the present invention, a biomass carbonization activation system coupled with a circulating fluidized bed is provided, comprising a circulating fluidized bed device and an activation device comprising at least one first activation tank and at least one second activation tank arranged in parallel.

[0028] Figure 1 Schematic diagram of the structure of a biomass carbonization activation system coupled with a circulating fluidized bed in an embodiment of the present invention.

[0029] like Figure 1 As shown, the circulating fluidized bed device includes a circulating fluidized bed carbonization furnace 1, which is suitable for converting the biomass raw material A into a first biomass char B and a mixture E containing a first combustible gas C and a second biomass char D through a carbonization reaction.

[0030] The activation device 4 is located downstream of the circulating fluidized bed device and includes at least one first activation tank 4a and at least one second activation tank 4b arranged in parallel, and the top of each activation tank is provided with a solid material inlet 41 and a feed valve 411 for the entry of the second biochar D, the bottom side wall is provided with a steam inlet 42 and a steam inlet valve 421 for the entry of superheated steam F to activate the second biochar D, the top side wall is provided with an activation gas discharge port 43 and an activation gas outlet valve 431 for discharging the first activation gas G generated by the activation of the second biochar D, and the bottom is provided with an activated carbon outlet 44 and an activated carbon outlet valve 441, as well as a return material outlet 45 and a return material valve 451; wherein at least one first activation tank 4a uses superheated steam F to activate the second biochar D, and the return material outlet 45 of at least one second activation tank 4b is connected to the return material port 11 of the dense phase zone of the circulating fluidized bed carbonization furnace 1 through a pipeline, and simultaneous return material and activation are achieved by controlling the respective valves of the first activation tank 4a and the second activation tank 4b, as well as alternating return material and activation.

[0031] In an embodiment of the present invention, the circulating fluidized bed carbonization furnace 1 is mainly used for carbonizing biomass raw materials to generate a first biochar B and a mixed material E. The activation device 4 activates the second biochar D entering the activation tank by a method of superheated steam F activation. Separating the carbonization of the biomass raw materials and the activation of the biochar is beneficial to obtaining higher quality biochar and activated carbon, and is beneficial to controlling the reaction. By controlling the opening and closing of the feed valve 411 and the return valve 451 on the activation tank, the material level of the second biochar D in the first activation tank 4a and the second activation tank 4b is controlled, and then the activation and return process in the first activation tank 4a and the second activation tank 4b is controlled. Specifically, by controlling the degree and timing of the opening of the feed valve 411 and the return valve 451, the second activation tank 4b is returned to the circulating fluidized bed carbonization furnace 1 while accumulating materials in the tank. While the second activation tank 4b is returning the material, superheated steam F enters the first activation tank 4a through the steam inlet 42 as an activation medium, activating the second biochar D of the first activation tank 4a. After the first activation tank 4a completes the activation reaction, the activated carbon M is discharged. At this time, the second biochar D in the second activation tank 4b also accumulates to a high material level. Close the feed valve 411 and the return valve 451 of the second activation tank 4b, open the steam inlet valve 421 and the activation gas outlet valve 431, and allow the second activation tank 4b to undergo an activation reaction, while the first activation tank 4a returns the material and accumulates the material by opening the feed valve 411 and the return valve 451. Through such a design, two or more first activation tanks 4a and second activation tanks 4b work alternately, meeting the continuous return and carbonization requirements of the circulating fluidized bed carbonization furnace 1 while meeting the requirements of the biochar activation time, achieving simultaneous activation and return, and improving the working efficiency of the circulating fluidized bed carbonization furnace 1 and the activation device 4. Furthermore, the activation reaction is a high-temperature process. The activation tanks contain high-temperature superheated steam F and solid materials (such as the second biochar D and activated carbon M). This wear and tear can affect the tanks' lifespan. Alternating activation and recycle times between the first and second activation tanks 4a, 4b can extend the lifespan of the activation tanks, maintaining the self-balancing carbonization and activation process longer and reducing time wasted replacing activation tanks.

[0032] According to an embodiment of the present invention, the system further comprises: a timing control unit for controlling the sequence and timing of opening and closing of each valve on the activation tank, as well as the degree of opening.

[0033] Specifically, if Figure 1As shown, the top of the circulating fluidized bed carbonization furnace 1 is provided with a mixed material outlet 12, the bottom is provided with a carbon discharge port 13 for discharging the first biochar B, and a carrier port 14 for the heat carrier H to enter, wherein the heat carrier can be hot flue gas after combustion of combustible gas or a solid heat carrier. Furthermore, the circulating fluidized bed device also includes: a gas-solid separator 3, which performs gas-solid separation on the mixed material E under the action of centrifugation to obtain the first combustible gas C and the second biochar D. The gas-solid separator 3 can be a high-efficiency cyclone separator or other high-efficiency gas-solid separator. Among them, the gas-solid separator 3 is provided with a mixed material inlet 31 connected to the mixed material outlet 12, an exhaust port 32 for discharging the first combustible gas C; and a solid material outlet 33 for discharging the second biochar D. The solid material outlet 33 is connected to the solid material inlet 41 of each activation tank. By controlling the various valves on each activation tank, the corresponding activation tank is activated and the material is returned.

[0034] Figure 2 Schematic diagram of the structure of the activation tank in the embodiment of the present invention.

[0035] like Figure 2 As shown, the activation tank includes a shell 401 , a fluidizing plate 402 , a guide tube 403 and an agitator 404 .

[0036] Specifically, part of the outer shell 401 is nested inside the guide tube 403, so that the outer shell 401 and the guide tube 403 form a sealed inner cavity of the activation tank. The height of the guide tube 403 can be 1 / 5 to 1 / 3 of the height of the activation tank, for example, it can be 1 / 3, 1 / 4, or 1 / 5, which is conducive to ensuring the contact time between the biochar and the superheated steam F and optimizing the activation effect; the outer shell nested inside the guide tube 403 is a fluidizing plate 402, which has a porous structure to form a fluidizing area for the superheated steam F. The steam inlet 42 is arranged on the guide tube 403 and is opposite to the fluidizing area, so that the superheated steam F entering the guide tube through the steam inlet 42 is evenly distributed in the inner cavity of the activation tank through the fluidizing plate 402, thereby achieving a better activation effect. There is a gap between the fluidizing plate 402 and the sealing bottom line of the guide tube 403, and the spacing of the gap is 200-500mm, so that the superheated steam F can enter the inner cavity of the activation tank from the gap, so that the second biochar D at the bottom is activated, which also helps to obtain a higher activation effect. The agitator 404 of the present invention is an electric variable frequency agitator, which includes a stirring motor, a stirring shaft controlled by the stirring motor, and a plurality of stirring blades arranged on the stirring shaft. The stirring blades can be distributed at equal or non-equal intervals to achieve full and uniform mixing of the superheated steam F and the second biochar D inside the activation tank, thereby improving the activation efficiency. Furthermore, a jacket is added to the outside of each activation tank to ensure that the activation temperature reaches 800-1000°C by external heating and temperature control, wherein the external heating medium can be selected from hot flue gas or by electric heating.

[0037] Continue as Figure 1 As shown, the activation system coupled with the circulating fluidized bed of the present invention further includes: an evaporator 6, a steam superheater 7, an activated gas cooler 8, a combustible gas storage tank 9, a biochar cooler 2 and an activated carbon cooler 5.

[0038] The evaporator 6, located downstream of the gas-solid separator 3, produces the second gas J and first steam K through heat exchange between the first gas C and deoxygenated water I. It is a key device for achieving energy recovery and process steam self-sufficiency. The first and second gas C and J have identical compositions, differing only in temperature. Their primary components include methane, carbon monoxide, and hydrogen. The evaporator 6 includes a water inlet 61 for the deoxygenated water I, a gas inlet 62 connected to the exhaust port 32 of the gas-solid separator 3, a gas outlet 63 for discharging the second gas J generated by the heat exchange between the first gas C and the deoxygenated water I, and first and second discharge ports 64 and 65 for discharging the first steam K generated by the heat exchange with the deoxygenated water I. A portion of the first steam K can be discharged through the first discharge port 64 for use in applications such as power generation, traction, and heating. The remaining portion of the first steam K can be discharged through the second discharge port 65 as an activation medium and then superheated in the downstream steam superheater 7.

[0039] The steam superheater 7 is provided with an activation gas inlet 71 connected to the activation gas discharge port 43 of each activation tank, a steam inlet 72 connected to the second discharge port 65 of the evaporator 6 for the entry of the first steam K, an activation gas outlet 73 for discharging the second activation gas L after the heat exchange between the first activation gas G and the first steam K, and a steam outlet 74 for discharging the superheated steam F generated after the heat exchange of the first steam K; and optionally, the activation gas outlet 73 of the steam superheater 7 is also connected to the pipeline between the return port 45 and the circulating fluidized bed carbonization furnace 1 through a pipeline, so as to use part of the second activated gas L as the return gas of the second biomass charcoal D.

[0040] In an embodiment of the present invention, the first activated gas G discharged from the activation tank has a certain amount of heat. It is transported to the steam superheater 7 through the activated gas inlet 71, which can further heat the first steam K discharged from the evaporator 6 while reducing the temperature of the first activated gas G to obtain second activated gas L and superheated steam F. Part of the second activated gas L is discharged through the activated gas outlet 73 and then enters the activated gas cooler 8 for cooling to obtain third activated gas O. Alternatively, part of the second activated gas L is used as return gas for the second biochar D, blowing the second biochar D into the carbonization furnace 1 for carbonization reaction. The first steam K is further heated by the first activated gas G in the steam superheater 7 to become superheated steam F. The superheated steam F escapes from the steam outlet 74 of the steam superheater 7 and then enters the activation tank through the steam inlet 42 to act as an activation medium and participate in the activation of the second biochar D.

[0041] The activated gas cooler 8 is equipped with a heat source inlet 81 connected to the activated gas outlet 73 of the steam superheater 7 for the second activated gas L, a cold source inlet 82 for the water N, a heat source outlet 83 for discharging the third activated gas O after the heat exchange between the second activated gas L and the water N, and a cold source outlet 84 for discharging the water N after the heat exchange. This activated gas cooler 8 is suitable for further recovering heat from the second activated gas L to prevent local overheating. It can also capture particulate matter, tar, or incompletely cracked organic matter in the second activated gas L, reducing pipeline blockage. Furthermore, the water discharged from the activated gas cooler 8 after heat exchange can be sent to a sewage treatment plant and recycled after purification, reducing waste.

[0042] The combustible gas storage tank 9 is connected to the combustible gas outlet 63 of the evaporator 6 at one end and to the heat source outlet 83 of the activated gas cooler 8 at the other end. The activated gas cooler 8 of the present invention fully utilizes the waste heat of the second activated gas L, and obtains the third activated gas O and the water N after the heat exchange by heat exchange between the second activated gas L and water N. The third activated gas O can be mixed with the second combustible gas J discharged from the evaporator 6 to obtain a mixed combustible gas. The obtained mixed combustible gas can be stored in the combustible gas storage tank 9 and transported as product gas. It should be noted that the third activated gas O and the second activated gas L have the same composition as the first activated gas G, and the only difference is the temperature, that is, the temperature of the first activated gas G> the temperature of the second activated gas L> the temperature of the third activated gas O. In the present invention, the steam superheater 7 can be a heat exchanger, the activated gas cooler 8 can be a tower, and the combustible gas storage tank 9 can be a gas cylinder or a gas cylinder.

[0043] The biomass cooler 2 is connected to the discharge port 13 of the circulating fluidized bed carbonization furnace 1 and is suitable for cooling the first biomass char B.

[0044] The activated carbon cooler 5 is connected to the activated carbon outlet 44 of each activation tank and is suitable for cooling the activated carbon M. The first biochar B and the activated carbon M can be cooled by air cooling or natural cooling.

[0045] As a second aspect of the present invention, a biomass carbonization and activation method coupled with a circulating fluidized bed is provided, which is performed by the above-mentioned biomass carbonization and activation system coupled with a circulating fluidized bed.

[0046] Figure 3 The flow chart of the biomass carbonization activation method coupled with a circulating fluidized bed in the embodiment of the present invention is as follows: Figure 1 The biomass carbonization activation system coupled with a circulating fluidized bed is described in detail.

[0047] like Figure 1 、 Figure 3As shown, the biomass carbonization and activation method includes: in a circulating fluidized bed carbonization furnace 1, biomass feedstock A undergoes a carbonization reaction to produce a first biochar B and a mixture E containing a first combustible gas C and a second biochar D; the second biochar D enters a first activation tank 4a and a second activation tank 4b of an activation device 4 for return and activation, including: controlling various valves on the first activation tank 4a to allow a portion of the second biochar D to enter at least one first activation tank 4a for activation by superheated steam F, thereby producing activated carbon M and a first activated gas G; simultaneously controlling various valves on the second activation tank 4b to allow a portion of the second biochar D to be returned to the circulating fluidized bed carbonization furnace 1 via at least one second activation tank 4b; controlling various valves on the first activation tank 4a and the second activation tank 4b to achieve simultaneous return and activation, as well as alternating activation and return; wherein the activation time is 1-3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours. Controlling the activation time to 1-3 hours ensures effective activated carbon activation and enables the production of high-value-added activated carbon.

[0048] According to an embodiment of the present invention, the carbon-containing biomass material can be referred to as biomass raw material A, which can specifically include straw, coal, sawdust or algae biomass. After being crushed and dried, the biomass raw material A enters the circulating fluidized bed carbonization furnace 1 for carbonization reaction, and is converted into a first biomass char B and a mixed material E, wherein the mixed material E includes a first combustible gas C and a second biomass char D. The first biomass char B and the second biomass char D have different carbon contents, and also differ in density or particle size. The first combustible gas C contains gases such as hydrogen, carbon monoxide, and methane. The first biomass char B is discharged from the circulating fluidized bed carbonization furnace 1 through the carbon discharge port 13 at the bottom of the carbonization furnace 1, and the mixed material E is discharged from the circulating fluidized bed carbonization furnace 1 through the mixed material outlet and enters the gas-solid separator 3.

[0049] According to an embodiment of the present invention, before the second biochar D enters the activation device 4 , the gas-solid separator 3 is used to perform gas-solid separation on the mixed material E to obtain the first combustible gas C and the second biochar D.

[0050] According to an embodiment of the present invention, the second biochar D enters the first activation tank 4a and the second activation tank 4b of the activation device for continuous return and activation. Figure 4 shown.

[0051] Figure 4 This is a schematic diagram of the process of alternately performing activation and material return in the activation tank in an embodiment of the present invention.

[0052] like Figure 3-4 and Figure 1 As shown, the second biochar D enters the first activation tank and the second activation tank of the activation device 4 for continuous material return and activation process including steps S1 to S5.

[0053] Step S1: Open the return valve 451 on the second activation tank 4b to enter the return mode, and at the same time close the return valve 451 on the first activation tank 4a to enter the activation mode, and turn on the agitator 404 in the first activation tank 4a. Specifically, the present invention sets at least one first activation tank 4a and at least one second activation tank 4b in parallel. By controlling the various valves on the activation tanks, two or more activation tanks can alternately perform activation and return work. When the first activation tank 4a is activating, the second activation tank 4b can be used as a returner to return (both the feed valve 411 and the return valve 451 are open). The above-mentioned return and activation process is achieved by controlling the opening and closing of the return valve 451 and the feed valve 411 on the first activation tank 4a and the second activation tank 4b. By turning on the agitator 404 of the first activation tank 4a, the second biochar D entering the first activation tank 4a is evenly mixed to prepare for activation.

[0054] Step S2: When the material level in the first activation tank 4a reaches a high level, the feed valve 411 of the first activation tank 4a is closed, and the activation gas outlet valve 431 and the steam inlet valve 421 on the first activation tank 4a are opened for activation. Specifically, the second biochar D enters the first activation tank 4a through the solid material inlet 41 and is accumulated and stored in the first activation tank 4a. When the second biochar D in the first activation tank 4a accumulates and reaches a high level, the feed valve 411 of the first activation tank 4a is closed to prepare for activation. At this time, the steam inlet valve 421 on the steam inlet 42 and the activation gas outlet valve 431 on the activation gas discharge port 43 are opened, and superheated steam F enters the first activation tank 4a and activates the second biochar D for 1-3 hours to obtain activated carbon M. The released first activation gas G is discharged through the activation gas discharge port 43 and enters the steam superheater 7 for subsequent heat exchange. Among them, the high material level, that is, the second biochar D reaches the 4 / 5 position of the tank body of the first activation tank 4a or the second activation tank 4b. If it is higher than the high material level, it is easy to be in a full tank state, and the material level of the second biochar D is higher than the solid material inlet 41, affecting the opening and closing of the feed valve 411 and the separation effect of the gas-solid separator 3; the low material level, that is, the 1 / 5 position of the tank body of the first activation tank 4a or the second activation tank 4b. If it is lower than the low material level, there is a risk of gas in the circulating fluidized bed carbonization furnace 1 being backflowed to the activation device.

[0055] Step S3: After activation of the second biochar D in the first activation tank 4a is completed, the steam inlet valve 421 of the first activation tank 4a is closed. After the pressure in the first activation tank 4a drops to a threshold, the activated gas outlet valve 431 of the first activation tank 4a is closed, and the activated carbon outlet valve 441 of the first activation tank 4a is opened to discharge the activated carbon M. Specifically, after activation of the second biochar D in the first activation tank 4a is completed, the introduction of superheated steam F is stopped, and the steam inlet valve 421 of the first activation tank 4a is closed. After the pressure in the first activation tank 4a drops to a threshold, the activated gas outlet valve 431 of the first activation tank 4a is closed, and the activated carbon outlet valve 441 of the first activation tank 4a is opened to discharge the activated carbon M in the first activation tank 4a.

[0056] Step S4: When the activated carbon M in the first activation tank 4a reaches a low material level, the activated carbon outlet valve 441 on the first activation tank 4a is closed. Specifically, during the discharge of the activated carbon M, when the activated carbon M in the first activation tank 4a reaches a low material level, the activated carbon outlet valve 441 of the first activation tank 4a is closed to stop the discharge of the activated carbon M. This ensures that sufficient return material remains in the first activation tank 4a for the circulating fluidized bed carbonization furnace 1, thereby maintaining stable operation of the circulating fluidized bed carbonization furnace 1.

[0057] Step S5: Open the feed valve 411 and the return valve 451 on the first activation tank 4a to enter the return mode, and at the same time close the return valve 451 and the feed valve 411 on the second activation tank 4b to enter the activation mode. Specifically, when the feed valve 411 and the return valve 451 on the first activation tank 4a are opened to enter the return mode, the material in the second activation tank 4b also accumulates to a high material level. At this time, the feed valve 411 and the return valve 451 on the second activation tank 4b are closed, and at the same time, the steam inlet valve 421 on the steam inlet 42 of the second activation tank 4b and the activation gas outlet valve 431 on the activation gas exhaust port 43 are opened to allow the superheated steam F to enter the second activation tank 4b and activate the second biochar D for 1-3 hours to obtain activated carbon M. The released first activation gas G is discharged through the activation gas exhaust port 43 and enters the steam superheater 7 for subsequent heat exchange.

[0058] In an embodiment of the present invention, specifically, while the first activation tank 4a is performing activation, the second activation tank 4b receives the second biochar D from the gas-solid separator 3. By controlling the return rate to be lower than the feed rate, it is ensured that while returning the material, a certain amount of material (second biochar D) can be accumulated in the second activation tank 4 to be activated. The activation reaction in the first activation tank 4a is completed and the activated carbon M is discharged. At this time, the first activation tank 4a enters a mode of executing return and accumulation of materials, thereby realizing alternating return and activation of multiple activation tanks, meeting the return requirements of the circulating fluidized bed carbonization furnace, and at the same time meeting the requirements of the biochar activation time (such as 1-3h), realizing simultaneous activation and return, and improving the working efficiency of the circulating fluidized bed carbonization furnace and the activation furnace. The activation tank uses superheated steam F activation method to improve the specific surface area and porosity of the biochar D and convert it into activated carbon M. The activated carbon M produced after activation enters the downstream activated carbon cooler 5 through the activated carbon outlet 44 for cooling. The incompletely activated second biochar D can be discharged through the return outlet 45 and then enter the circulating fluidized bed carbonization furnace 1 through the return port 11. The first activated gas G produced during the activation process can be recovered through purification to increase its calorific value, and its waste heat can be effectively utilized.

[0059] Continue as Figure 1 、 Figure 3 As shown, the biomass carbonization activation method further includes: passing the first combustible gas C and deoxygenated water I into an evaporator 6 for heat exchange and gasification, respectively, to produce a second combustible gas J and a first steam K; wherein the first combustible gas C and the second combustible gas J have the same composition, and the temperature of the first combustible gas C is greater than that of the second combustible gas J. Specifically, during the heat exchange and gasification reaction within the evaporator 6, the first combustible gas C transfers heat to the deoxygenated water I, gasifying it into the first steam K, while the first combustible gas C cools down to become the second combustible gas J. A portion of the first steam K serves as a heat source and enters the steam superheater 7 for heat exchange with the first activated gas G entering the steam superheater 7, heating the first steam K into superheated steam F, which serves as an activation medium, thereby effectively utilizing the heat of the first steam K; the remaining portion of the first steam K is discharged as product steam.

[0060] Continue as Figure 1 、 Figure 3As shown, the biomass carbonization activation method further includes: passing the first activated gas G and a portion of the first steam K into a steam superheater 7, using the first activated gas G to heat the first steam K to obtain a second activated gas L and superheated steam F, wherein the second activated gas L has the same composition as the first activated gas G and the temperature of the second activated gas L is lower than that of the first activated gas G. Furthermore, a portion of the second activated gas L is passed into an activated gas cooler 8 and cooled by water N to form a third activated gas O and water after heat exchange; the remaining portion of the second activated gas L serves as return gas for the second biochar D and enters a return pipe of the activation tank, and the second biochar D in the activation tank is returned to the carbonization furnace 1 for recycling.

[0061] Xu Ru Figure 1 、 Figure 3 As shown, the biomass carbonization activation method further includes mixing the third activated gas O with the second combustible gas J, which is then stored in a combustible gas storage tank 9 and delivered as a mixed combustible gas product. Water N is heated and discharged after heat exchange and can be recycled after purification. Water N also purifies the second activated gas L, reducing the amount of particulate matter, tar, or incompletely cracked organic matter in the second activated gas L and reducing pipeline blockage.

[0062] According to an embodiment of the present invention, continue as Figure 3 As shown, the biomass carbonization activation method further includes: cooling the first biochar B by using a biochar cooler 2, and transporting it as a product after cooling it to below 100°C.

[0063] According to an embodiment of the present invention, continue as Figure 3 As shown, the biomass carbonization activation method further includes: using an activated carbon cooler 5 to cool the activated carbon M, which can be sent out as a product after cooling.

[0064] In summary, the present invention provides a biomass carbonization activation system and method coupled with a circulating fluidized bed. By setting an activation device composed of a plurality of activation tanks, the second biochar D separated by the gas-solid separator is activated by superheated steam F to obtain activated carbon. A solid material inlet 41, a steam inlet 42, an activation gas discharge port 43, an activated carbon outlet 44, a return material outlet 45 and corresponding valves are set on the activation tank to ensure that part of the first activation tank 4a performs activation work for 1-3 hours while the other part of the second activation tank 4b returns the material to the circulating fluidized bed carbonization furnace 1, so as to solve the problem of insufficient biochar activation time and poor activated carbon quality caused by ensuring continuous return of material to the circulating fluidized bed carbonization furnace 1, and also solve the problem of the carbonization furnace being unable to continuously carbonize due to ensuring the activation time. The first activated gas G discharged from the activation tank contains a large amount of superheated steam F with a high temperature and low calorific value. It is cooled by the steam superheater 7 and is used to heat the first steam K to obtain the superheated steam F for activation. After the first activated gas G is cooled, it becomes the second activated gas L. A portion of the second activated gas L enters the circulating fluidized bed carbonization furnace 1 as return air, and the other portion enters the activated gas purifier 8 and is further cooled by water (such as circulating spray water). The steam in the second activated gas L is condensed, and the calorific value of the obtained third activated gas O is increased. It is mixed with the second combustible gas J discharged from the steam generator 6 and sent out as a product. By purifying the first activated gas G through this method, the heat in the first activated gas G can be recovered, thereby improving the quality of the activated gas and being more energy-saving and environmentally friendly.

[0065] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A biomass carbonization activation system coupled with a circulating fluidized bed, characterized in that: The biomass carbonization activation system comprises: A circulating fluidized bed device, comprising a circulating fluidized bed carbonization furnace, wherein the circulating fluidized bed carbonization furnace is adapted to convert a biomass raw material into a first biomass char and a mixture comprising a first combustible gas and a second biomass char through a carbonization reaction; an activation device, located downstream of the circulating fluidized bed device, comprising at least one first activation tank and at least one second activation tank arranged in parallel, wherein the top of each activation tank is provided with a solid material inlet and a feed valve for entry of the second biochar, a steam inlet and a steam inlet valve for entry of superheated steam to activate the second biochar, an activation gas discharge port and an activation gas outlet valve for discharging the first activation gas generated by activation of the second biochar are provided on the top sidewall, and an activated carbon outlet and an activated carbon outlet valve, as well as a return material outlet and a return material valve are provided on the bottom; At least one first activation tank uses superheated steam to activate the second biochar, and the return outlet of at least one second activation tank is connected to the return port of the dense phase zone of the circulating fluidized bed carbonization furnace through a pipeline. By controlling the various valves of the first activation tank and the second activation tank, simultaneous return and activation are achieved, as well as alternating return and activation.

2. The biomass carbonization activation system according to claim 1, characterized in that: The circulating fluidized bed carbonization furnace is provided with a mixed material outlet at the top, a carbon discharge port for discharging the first biochar, and a carrier port for entering a heat carrier at the bottom; as well as The circulating fluidized bed device further comprises: a gas-solid separator; The gas-solid separator is provided with a mixed material inlet connected to the mixed material outlet, an exhaust port for discharging the first combustible gas; and a solid material outlet for discharging the second biochar, and the solid material outlet is connected to the solid material inlet of each activation tank.

3. The biomass carbonization activation system according to claim 1, characterized in that: The activation tank also includes a shell, a fluidizing plate, a guide tube and an agitator; Part of the outer shell is nested inside the guide tube, so that the outer shell and the guide tube form a sealed inner cavity of the activation tank; The outer shell nested inside the guide tube is a fluidizing plate, and the fluidizing plate has a porous structure to form a fluidizing area for superheated steam. The steam inlet is arranged on the guide tube and faces the fluidizing area. There is a gap between the fluidizing plate and the bottom sealing line of the guide tube, and the spacing of the gap is 200-500mm; The height of the guide tube is 1 / 5 to 1 / 3 of the height of the activation tank.

4. The biomass carbonization activation system according to any one of claims 1 to 3, characterized in that: The biomass carbonization activation system also includes: an evaporator, located downstream of the gas-solid separator, provided with a water inlet for deoxygenated water, a combustible gas inlet connected to the exhaust port of the gas-solid separator, a combustible gas outlet for discharging a second combustible gas generated after heat exchange between the first combustible gas and the deoxygenated water, and a first discharge port and a second discharge port for discharging a first steam generated after heat exchange with the deoxygenated water; and / or a steam superheater, provided with an activation gas inlet connected to the activation gas discharge port of each activation tank, a steam inlet connected to the second discharge port of the evaporator for entering the first steam, an activation gas outlet for discharging the second activation gas after the heat exchange between the first activation gas and the first steam, and a steam outlet for discharging the superheated steam generated after the heat exchange between the first steam and the second activation gas; and Optionally, the activated gas outlet of the steam superheater is also connected to the pipeline between the return port and the circulating fluidized bed carbonization furnace through a pipeline, so that part of the second activated gas is used as the return gas of the second biochar.

5. The biomass carbonization activation system according to claim 4, characterized in that: The biomass carbonization activation system also includes: a biochar cooler connected to the discharge port of the circulating fluidized bed carbonization furnace and adapted to cool the first biochar; and / or an activated carbon cooler connected to the activated carbon outlet of each activation tank and suitable for cooling the activated carbon; and / or an activated gas cooler, provided with a heat source inlet connected to the activated gas outlet of the steam superheater for the entry of the second activated gas, a cold source inlet for the entry of water, a heat source outlet for discharging the third activated gas after the heat exchange between the second activated gas and the water, and a cold source outlet for discharging the water after the heat exchange; A combustible gas storage tank is connected to the combustible gas outlet of the evaporator at one end and to the heat source outlet of the activated gas cooler at the other end to store a mixed gas of the third activated gas and the second combustible gas.

6. A biomass carbonization and activation method coupled with a circulating fluidized bed, performed by the biomass carbonization and activation system according to any one of claims 1 to 5, characterized in that: The biomass carbonization activation method comprises: In a circulating fluidized bed carbonization furnace, the biomass raw material undergoes a carbonization reaction to produce a first biomass char and a mixed material including a first combustible gas and a second biomass char; The second biomass char enters the first activation tank and the second activation tank of the activation device for return and activation, including: controlling the valves on the first activation tank so that part of the second biomass char enters at least one of the first activation tanks to be activated by superheated steam to produce activated carbon and first activation gas; simultaneously controlling the valves on the second activation tank so that part of the second biomass char is returned to the circulating fluidized bed carbonization furnace via at least one of the second activation tanks, controlling the valves on the first activation tank and the second activation tank to achieve simultaneous return and activation, and alternately performing activation and return; Wherein, the activation time is 1-3h.

7. The biomass carbonization activation method according to claim 6, characterized in that: Before the second biochar enters the activation device, it includes: The gas-solid separator is used to perform gas-solid separation on the mixed material to obtain a first combustible gas and a second biomass charcoal.

8. The biomass carbonization activation method according to claim 7, characterized in that: The biomass carbonization activation method further comprises: Passing a first combustible gas and deoxygenated water into an evaporator for heat exchange and gasification, respectively, to obtain a second combustible gas and a first steam; wherein the first combustible gas and the second combustible gas have the same composition, and the temperature of the first combustible gas is greater than the temperature of the second combustible gas; and / or The first activated gas and part of the first steam are introduced into a steam superheater, and the first steam is heated by the first activated gas to obtain a second activated gas and the superheated steam, and the remaining part of the first steam is sent out as product steam; wherein, the second activated gas has the same composition as the first activated gas, and the temperature of the second activated gas is lower than the temperature of the first activated gas.

9. The biomass carbonization activation method according to claim 8, characterized in that: The biomass carbonization activation method also includes: Part of the second activated gas is passed into an activated gas cooler and cooled by water to obtain a third activated gas, and the remaining part of the second activated gas is used as the return gas of the second biochar; and The third activated gas is mixed with the second combustible gas and stored in a combustible gas storage tank after mixing; and / or Cooling the first biochar using a biochar cooler; and / or The activated carbon is cooled using an activated carbon cooler.

10. The biomass carbonization activation according to claim 6, characterized in that: The second biomass char enters the first activation tank and the second activation tank of the activation device for return and activation, which includes: Opening the return valve on the second activation tank to enter the return mode, while closing the return valve on the first activation tank to enter the activation mode, and starting the agitator in the first activation tank; When the material level in the first activation tank reaches a high level, the feed valve of the first activation tank is closed, and the activation gas outlet valve and steam inlet valve on the first activation tank are opened to perform activation; After activation of the second biochar in the first activation tank is completed, the steam inlet valve on the first activation tank is closed, and after the pressure in the first activation tank drops to a threshold, the activated gas outlet valve on the first activation tank is closed, and the activated carbon outlet valve on the first activation tank is opened to discharge the activated carbon; When the first activation tank reaches a low material level, closing the activated carbon outlet valve on the first activation tank; The feed valve and the return valve on the first activation tank are opened to enter the return mode, and the return valve and the feed valve on the second activation tank are closed to enter the activation mode.

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