Drying, carbonizing and activating integrated method for preparing bamboo activated carbon

Abstract

The invention discloses a drying, carbonizing and activating integrated method for activated carbon preparation. The drying, carbonizing and activating integrated method comprises the steps of water-containing feeding, catalytic decoking, fuel gas distribution, high-temperature combustion, activated combustion, integrated activating, integrated carbonizing and integrated drying. According to the integrated method, combustible components in dried tail gas are utilized to form high temperature for activation, then waste heat of activated tail gas is utilized for carbonization, and waste heat of carbonized tail gas is further utilized for drying, so that energy self-circulation is formed; meanwhile, according to the integrated method, self-contained water vapor of the raw materials is utilized, and water vapor is reversely provided for the activation process through circulation of the self-contained water vapor; the method can realize integration of drying, carbonization and activation processes in bamboo activated carbon production, and has the characteristics of energy self-supply, high production efficiency and low process energy consumption. The method not only can be applied to preparation of activated carbon by taking bamboo as a raw material, but also can be applied to preparation of activated carbon by taking wood, coconut shells, fruit shells and other biomass raw materials.

Description

Technical Field

[0003] The invention relates to the technical field of biomass activated carbon preparation, and is a method for preparing physical activated carbon from biomass raw materials such as bamboo, and in particular to an integrated drying, carbonization and activation method for preparing bamboo activated carbon. Background Art

[0005] Biomass activated carbon is a porous material obtained by high-temperature carbonization and activation of biomass raw materials (including bamboo, wood, coconut shell, fruit shell, etc.). Its surface contains rich active groups and has strong adsorption properties. Because biomass activated carbon has rich void structures, it has strong adsorption capacity for small molecules. At the same time, biomass activated carbon has a high specific surface area, pore volume and porosity, good permeability, thermal conductivity and stability. Biomass activated carbon has been widely used in various fields such as chemical industry, environmental protection, food processing, metallurgy, drug refining, military chemical protection, etc.

[0006] my country is the country with the richest bamboo resources, the largest bamboo forest area, and the highest bamboo production in the world, and is known as the "Bamboo Kingdom". Bamboo grows fast and matures early. A bamboo can be mature in two or three years, and its growth cycle is much shorter than other fast-growing tree species. Replacing wood with bamboo is one of the best ways to achieve sustainable development. Similarly, bamboo has a high content of lignin and cellulose, which can achieve a high fixed carbon content and a developed pore structure, making it an ideal raw material for the preparation of activated carbon. In the field of activated carbon, vigorously developing bamboo activated carbon to replace coal-based activated carbon and wood-based activated carbon can not only effectively alleviate the contradiction between wood supply and demand in my country, but also alleviate carbon emissions and ecological environment problems.

[0007] At present, the physical method of preparing bamboo activated carbon is divided into two stages: carbonization stage and activation stage. In the carbonization stage, the raw materials are carbonized by a carbonization furnace, mainly using anoxic or anoxic dry distillation process; the temperature and time of the carbonization treatment are controlled by a formulated temperature curve to prepare the raw materials into carbonized materials. In the activation stage, the carbonized materials are further activated by an activation furnace, and the main process is "high-temperature steam activation"; steam and air are added to the activation furnace to re-form a high-temperature reaction environment, so that the pores on the surface of the carbonized material are fully opened and gradually converted into bamboo activated carbon.

[0008] The current two-stage preparation process and system for bamboo activated carbon have some problems: (1) It occupies a large area and has a complex process; (2) The carbonized material needs to be cooled in the first stage and then reactivated in the second stage, which results in high energy consumption and low production efficiency; (3) In the "high-temperature steam activation" process, additional water vapor needs to be added, resulting in energy waste; (4) During the activation process, a portion of the carbonized material needs to be ablated to form a high-temperature reaction environment, thereby reducing the yield of bamboo activated carbon.

[0009] Therefore, the present invention provides an integrated drying, carbonization and activation method for preparing bamboo activated carbon, which directly prepares the raw material into bamboo activated carbon, and at the same time fully utilizes the self-contained water vapor of the raw material and the combustible components produced during the carbonization process to provide the high temperature and high water vapor content conditions required for activation. The method provided by the present invention can improve production efficiency, reduce process energy consumption, reduce water vapor consumption, and improve the final yield of activated carbon. The method provided by the present invention can be applied not only to bamboo as raw material, but also to the preparation of activated carbon from other biomass raw materials such as wood, coconut shells, and fruit shells. Summary of the invention

[0011] The present invention provides an integrated drying, carbonization and activation method for preparing bamboo activated carbon, which uses the water vapor contained in the raw material to provide the necessary water vapor for the activation process; at the same time, the drying, carbonization and activation are integrated in an integrated rotary kiln to simplify the equipment; further, the tail gas of the activation process is used to provide a heat source for carbonization, and the tail gas of the carbonization process is used to provide a heat source for drying, thereby improving the energy utilization rate. The integrated drying, carbonization and activation method can overcome the problems existing in the existing bamboo activated carbon preparation process and method.

[0012] The technical solution of the present invention is achieved in this way:

[0013] A drying, carbonization and activation integrated method for preparing bamboo activated carbon, comprising:

[0014] (1) Feeding with water: Take biomass raw materials with a moisture content greater than 30%, and directly feed the raw materials with water into the integrated rotary kiln without drying;

[0015] (2) Catalytic decoking: The drying tail gas of the integrated rotary kiln is introduced, and the high-temperature flue gas of the combustion furnace is also introduced synchronously; the decoking temperature is controlled at the same time, so that the drying tail gas is mixed and heated to a medium temperature; the tar contained in the drying tail gas is fully cracked under the action of the self-contained water vapor and catalyst to form decoking gas; the drying tail gas is a gaseous product of the drying, carbonization and activation process, has a low temperature, is flammable and rich in tar and self-contained water vapor; the temperature of the decoking gas is medium temperature;

[0016] (3) Gas distribution: the decoking gas is divided into two parts, one part of the decoking gas is used for activation combustion, and the other part of the decoking gas is used as fuel gas for high-temperature combustion. In principle, the activation combustion is first satisfied, and the excess is then distributed to the high-temperature combustion.

[0017] (4) High-temperature combustion: The gas is fully burned with oxygen in a gas combustion furnace, and the combustion temperature is controlled to generate high-temperature flue gas; a portion of the high-temperature flue gas is used for catalytic decoking and activation combustion, and the excess high-temperature flue gas is led out to the waste heat utilization equipment for energy recovery, and its tail gas is discharged;

[0018] (5) Activated combustion: converting the decoking gas distributed from the fuel gas into high-humidity flue gas; the high-humidity flue gas is a gaseous product of the activated combustion, has a high temperature, has an oxygen content of zero and contains a large amount of self-contained water vapor;

[0019] (6) Integrated activation: The high-humidity flue gas is introduced into the integrated rotary kiln to provide a high-temperature, high-water vapor content atmosphere and heat source for the activation zone of the integrated rotary kiln; the carbonized material undergoes an activation reaction under the atmosphere conditions, the solid product is activated carbon, and the gaseous product is activated exhaust gas; the activated carbon is cooled to room temperature by a cooler and packaged.

[0020] (7) Integrated carbonization: The activated tail gas then enters the carbonization zone of the integrated rotary kiln, providing a sub-high temperature atmosphere and heat source for the carbonization zone; the dehydrated raw material undergoes a carbonization reaction under the atmosphere, the solid product is the carbonized material, and the gaseous product is the carbonized tail gas;

[0021] (8) Integrated drying: The carbonized tail gas then enters the drying zone of the integrated rotary kiln, providing a medium-temperature atmosphere and heat source for the drying zone; the water-containing raw material is dried and dehydrated under the atmosphere, the solid product is the dehydrated raw material, and the gaseous product is the drying tail gas.

[0022] In the present invention, the activated combustion can be carried out in a single-stage combustion mode or a two-stage combustion mode; the single-stage combustion mode refers to directly introducing the decoked gas into the burner and then adding a small amount of air for incomplete combustion; at the same time, the activated combustion control is directly carried out to generate high-temperature and high-humidity flue gas;

[0023] The two-stage combustion method refers to adding deoxygenation combustion to the single-stage combustion method, that is, first performing deoxygenation combustion and then performing activation combustion; the deoxygenation combustion refers to combustion with the high-temperature flue gas as an oxidant and the decoking gas as fuel, with the goal of consuming the oxygen in the high-temperature flue gas; at the same time, deoxygenation combustion control is performed to make the combustion temperature sub-high temperature, and the combustion product is activated gas; the activated gas is an oxygen-free gas containing the self-contained water vapor and combustible components; the activation combustion under this method refers to using the activated gas as fuel and adding a small amount of air for incomplete combustion; at the same time, activation combustion control is performed to produce high-temperature and high-humidity flue gas;

[0024] The single-stage combustion method has a simple structure and directly converts the decoking gas into the high-humidity flue gas required for the activation process; however, the single-stage combustion method has a relatively high requirement for the calorific value of the decoking gas and is more suitable for bamboo raw materials with a moisture content of 30% to 40%; the two-stage combustion method is implemented in two stages: first, deoxygenation combustion is performed to generate sub-high temperature activated gas; then the activated gas is burned to generate high-temperature high-humidity flue gas; the temperature of this combustion method is easier to control, so it is more suitable for bamboo raw materials with a high moisture content (for example, >40%), or biomass raw materials with a low calorific value (such as eucalyptus, fir, etc.);

[0025] In the present invention, the high temperature is above 800°C, the sub-high temperature is between 450°C and 800°C, the medium temperature is between 250°C and 450°C, and the low temperature is below 250°C.

[0026] In some embodiments, the catalyst is Ni-CaO, which can increase the cracking rate of tar in the catalytic decoking and reduce the temperature required for tar cracking;

[0027] In some embodiments, (1) the decoking temperature control refers to the online collection of the decoking gas temperature. If the decoking gas temperature is lower than the medium temperature, the high-temperature flue gas flow rate is increased through a valve, otherwise the high-temperature flue gas flow rate is reduced; (2) the combustion temperature control refers to the online collection of the high-temperature flue gas temperature, and the high-temperature flue gas temperature is always kept at the high temperature by adjusting the air volume of the gas combustion furnace; (3) the deoxygenation temperature control refers to the online collection of the activated gas temperature. If the activated gas temperature is lower than the sub-high temperature, the high-temperature flue gas flow rate is increased through a valve, otherwise the high-temperature flue gas flow rate is reduced; (4) the activation temperature control refers to the online collection of the high-humidity flue gas temperature, and the high-humidity flue gas temperature is always kept at the high temperature by adjusting the air volume of the activation burner.

[0028] In the present invention, the water vapor required for the integrated activation comes from the self-contained water vapor; the self-contained water vapor is the water vapor formed by the raw materials and the water carried, including physical water and chemically synthesized water; the biomass raw materials will also decompose to form water molecules during the carbonization process, which belong to chemically synthesized water molecules and also come from the raw materials, so they also belong to self-contained water vapor. In the existing activated carbon activation process, additional water vapor is added to achieve the activation atmosphere conditions, which are mainly high temperature and high humidity (high water vapor content); but in the present invention, the self-contained water vapor of the raw materials is fully utilized, and through the circulation of the self-contained water vapor, water vapor is provided for the activation process in turn.

[0029] In some embodiments, if the moisture content of the biomass raw material is less than 30%, the self-contained water vapor content will be low, which makes it difficult to meet the water vapor required in the integrated activation process; then, additional water vapor can be supplemented to the activation zone.

[0030] In the present invention, the high temperature required for the integrated activation comes from the combustible components in the drying tail gas. In the existing activated carbon activation process, part of the carbon powder is burned to generate the high temperature required for the activation process. However, in the present invention, the combustible components (mainly CO, H2, CH4 and tar) generated during the integrated activation and integrated carbonization processes are fully utilized. These combustible components are contained in the drying tail gas. The present invention fully utilizes and recycles the combustible components in the drying tail gas through processes such as catalytic decoking, high-temperature combustion, deoxygenated combustion (two-stage combustion method), and activated combustion to generate the high temperature conditions required in the integrated activation process.

[0031] In the present invention, the self-contained water vapor is fully utilized, and the self-contained water vapor is recycled. In some embodiments, the recycling of the self-contained water vapor is specifically as follows: (1) the self-contained water vapor is contained in the drying tail gas for catalytic decoking; (2) the self-contained water vapor is contained in the decoking gas for deoxygenated combustion (two-stage combustion method); (3) the self-contained water vapor is contained in the activated gas for activated combustion; (4) the self-contained water vapor is contained in the high-humidity flue gas for integrated activation; (5) the self-contained water vapor is contained in the activated tail gas for integrated carbonization; (6) the self-contained water vapor is contained in the carbonized tail gas for integrated drying; finally, the self-contained water vapor is contained in the decoking gas again, and this cycle is repeated to form a recycling process.

[0032] In the present invention, the self-contained water vapor is heated outside the integrated rotary kiln and cooled inside the integrated rotary kiln. In some embodiments, the self-contained water vapor is heated 2 to 3 times outside the integrated rotary kiln and cooled 3 times inside the integrated rotary kiln; the heating includes: (1) catalytic decoking, the self-contained water vapor temperature is raised from the low temperature to the medium temperature; (2) deoxygenated combustion (two-stage combustion method), the self-contained water vapor temperature is raised from the medium temperature to the sub-high temperature; (3) activated combustion, the self-contained water vapor temperature is raised from the sub-high temperature to the high temperature; the cooling includes: (1) integrated activation, the self-contained water vapor temperature is lowered from the high temperature to the sub-high temperature; (2) integrated carbonization, the self-contained water vapor temperature is lowered from the sub-high temperature to the medium temperature; (3) integrated drying, the self-contained water vapor temperature is lowered from the medium temperature to the low temperature.

[0033] In combination with the drying, carbonization and activation integrated method for preparing bamboo activated carbon provided in the present invention, it can be realized by a specific device. An integrated drying, carbonization and activation device for preparing bamboo activated carbon comprises:

[0034] An integrated rotary kiln realizes the functions of integrated drying, integrated carbonization, and integrated activation in the integrated method provided in the present invention; the integrated rotary kiln has a rotary kiln shape, including: a rotary kiln body, a feeder, a drying tail gas outlet, a feeding end, a carbon discharge cabinet, and a carbon discharge cooler; the feeder is installed on the feeding end, and the raw material enters the rotary kiln body from the feeder; the drying tail gas outlet is opened on the feeding end for discharging the drying tail gas; the feeding end is a cavity arranged on the feeding side of the rotary kiln body for collecting gaseous products; the carbon discharge cabinet is a cabinet arranged on the discharging side of the rotary kiln body; the carbon discharge cooler is arranged at the bottom of the carbon discharge cabinet to cool and discharge the prepared activated carbon;

[0035] A catalytic decoking device, realizing the function of catalytic decoking in the integrated method provided in the present invention; the catalytic decoking device is a device for catalytic decoking, comprising: a high-temperature shell, a high-temperature flue gas inlet, a drying exhaust gas inlet, and a decoking outlet; the drying exhaust gas enters the high-temperature shell from the drying exhaust gas inlet; the high-temperature flue gas enters the high-temperature shell from the high-temperature flue gas inlet; the decoked gas carrying water vapor and micro-carbon powder is led out from the decoking outlet;

[0036] A solid-gas distributor, realizing the function of gas distribution in the integrated method provided in the present invention; the solid-gas distributor is a device for distributing the decoking gas and the contained micro-carbon powder, comprising: a distribution gas inlet, a gas outlet, and a decoking gas outlet; the distribution gas inlet is used to introduce the decoking gas; the gas is decoking gas without micro-carbon powder, which is led out from the gas outlet; the decoking gas containing micro-carbon powder is led out from the decoking gas outlet;

[0037] a decoking air induced draft fan, which provides power for the internal gas flow of the catalytic decoking device and the solid-gas distributor; the air inlet of the decoking air induced draft fan is connected to the decoking air outlet of the catalytic decoking device; the air outlet of the decoking air induced draft fan is connected to the distribution air inlet of the solid-gas distributor;

[0038] A gas combustion furnace realizes the function of high-temperature combustion in the integrated method provided in the present invention; the gas combustion furnace is a device for high-temperature combustion of the gas, comprising: a gas inlet and three flue gas outlets, namely: a waste heat outlet, a decoking outlet and an activation outlet; the gas inlet is connected to the gas outlet of the solid-gas distributor to introduce the gas; the waste heat outlet is connected to the waste heat utilization equipment to realize the utilization and recovery of thermal energy; the decoking outlet is connected to the high-temperature flue gas inlet of the catalytic decoking device;

[0039] A deoxygenation burner, which realizes the function of deoxygenation combustion in the two-stage combustion mode in the integrated method provided in the present invention; the deoxygenation burner is a device for deoxygenation combustion, comprising: an oxygen-containing inlet, a fuel inlet, and an activated gas outlet; the oxygen-containing inlet is connected to the activated outlet of the gas combustion furnace to introduce the high-temperature flue gas; the fuel inlet is connected to the decoking gas outlet of the solid-gas distributor;

[0040] An activation burner, which realizes the activation combustion function of the two-stage combustion mode in the integrated method provided in the present invention; the activation burner is installed on the carbon output cabinet, and generates the high-humidity flue gas to provide heat source and water vapor for the activation, carbonization and drying processes;

[0041] An activated air induced draft fan, which provides power for the internal gas flow of the deoxygenation burner and the activation burner; the air inlet of the activated air induced draft fan is connected to the activation air outlet of the deoxygenation burner; the air outlet of the activated air induced draft fan is connected to the activation burner to provide fuel for the activation burner.

[0042] In some embodiments, the temperature inside the rotary kiln body is divided into an activation zone (corresponding to high temperature), a carbonization zone (corresponding to sub-high temperature) and a drying zone (corresponding to medium temperature) from high to low; the outside of the rotary kiln body is wrapped with a heat-insulating material; the inside of the activation zone is embedded with a high-temperature refractory material; the high-temperature atmosphere in the activation zone is provided by the high-humidity flue gas of the activation burner; the sub-high-temperature atmosphere in the carbonization zone is provided by the activated tail gas in the activation zone; the medium-temperature atmosphere in the drying zone is provided by the carbonization tail gas in the carbonization zone; on the discharge side of the rotary kiln body, a positive pressure is formed by the activated gas induced draft fan through the activation burner; on the feed side of the rotary kiln body, a negative pressure is formed by the decoking gas induced draft fan through the drying tail gas outlet; the internal gas of the rotary kiln body is blown from the activation zone to the drying zone flow; preferably, the rotary kiln body is equipped with a high temperature resistant lifting plate, so that the raw materials can be fully stirred and reacted evenly; preferably, the rotary kiln body is provided with multiple parallel axial water vapor pipes outside, the water vapor pipes are connected to each other and connected to the steam source through a rotary joint; preferably, the water vapor pipe is provided with multiple steam inlets and inserted into the activation zone to replenish water vapor for the activation zone; preferably, the water vapor pipe is provided with a steam valve, when the moisture content of the raw materials is low (preferably, the moisture content is less than 30%), the steam valve is opened to replenish water vapor; preferably, only the steam valve of the water vapor pipe at the bottom of the rotary kiln body is opened, so that the water vapor directly contacts the carbon layer (at the bottom of the rotary kiln) to promote the activation reaction. Preferably, the feeder can be in the form of a feeding screw; preferably, the carbon outlet cooler can be in the form of a rotary slag cooler. Preferably, a thermocouple is set in the activation zone, a variable frequency speed regulator is set for the blower of the activation burner, and the activation temperature control is implemented on the activation burner, so that the temperature of the activation zone is always at the high temperature.

[0043] In some embodiments, the catalytic decoking device is directly installed on the top of the feed end to reduce the condensation of tar in the drying exhaust gas during transportation. A mixer is provided in the high-temperature shell of the catalytic decoking device to fully mix the drying exhaust gas and the high-temperature flue gas; preferably, the mixer adopts a structure of a nozzle array and a propeller blade; a catalyst partition is also provided on the outlet side of the high-temperature shell, and the catalyst partition is a partition made of catalyst material; preferably, a honeycomb pore array is provided on the catalyst partition; preferably, the catalyst material is Ni-CaO; preferably, the high-temperature shell is connected to a steam pipeline and is equipped with a steam valve, and when the moisture content of the biomass raw material is low (preferably, the moisture content is less than 30%), sufficient water vapor is provided inside the high-temperature shell; preferably, a thermocouple is provided at the decoking outlet, and a high-temperature valve is provided outside the high-temperature flue gas inlet to implement the decoking temperature control of the catalytic decoking device.

[0044] In some embodiments, the solid-gas distributor adopts a spring-type pipe structure; the inlet of the spring-type pipe is set as the distribution air inlet, and the outlet of the spring-type pipe is set as the decoking air outlet; a plurality of air holes are opened on the inner wall of the spring-type pipe and connected to the central area of ​​the spring-type pipe; the central area is closed and an outlet is set as the gas outlet; the decoked gas enters from the distribution air inlet and flows along the spring-type pipe; the micro-carbon powder contained in the decoked gas is enriched in the outer wall area of ​​the spring-type pipe under the action of centrifugal force; the decoked gas containing carbon powder is drawn out from the decoking air outlet; the gas not containing micro-carbon powder enters the central area through the air holes and is then drawn out from the gas outlet.

[0045] In some embodiments, the gas combustion furnace is equipped with an auxiliary burner for igniting the furnace and ensuring stable combustion of the gas combustion furnace; preferably, the auxiliary burner can be a biomass particle burner; preferably, a thermocouple is provided at the outlet of the gas combustion furnace, and a variable frequency speed regulator is provided for the blower to implement the combustion temperature control of the gas combustion furnace.

[0046] In some embodiments, the deoxygenation burner adopts a front-to-back double-chamber structure of a mixing chamber and a combustion chamber, wherein the mixing chamber further adopts an inner and outer double-layer structure, consisting of an outer shell and an inner tube body; the outer shell is connected to the oxygen-containing inlet; the inner tube body is connected to the fuel inlet and is inserted into the outer shell; the inner tube body is provided with air holes, so that the high-temperature flue gas can enter the inner tube body through the air holes; in the inner tube body, the high-temperature flue gas is mixed with the carbon-containing gas; it is sprayed into the combustion chamber for combustion, and the generated activated gas is then led out from the activated gas outlet; preferably, a thermocouple is provided at the activated gas outlet, an oxygen regulating valve is provided outside the oxygen-containing inlet, and a fuel valve is provided outside the fuel inlet, so as to implement the deoxygenation temperature control of the deoxygenation burner.

[0047] The method provided by the present invention can be applied not only to the preparation of activated carbon using bamboo as raw material, but also to other biomass raw materials such as wood, coconut shell, fruit shell, etc.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) Through the integrated method of drying, carbonization and activation, the raw materials are continuously heated from room temperature, and successively experience the atmosphere of medium temperature (drying zone), sub-high temperature (carbonization zone) and high temperature (activation zone), and are directly converted into activated carbon, thereby improving production efficiency;

[0050] (2) The activated tail gas from the activation zone is used to provide heat energy for the carbonization zone, and the carbonized tail gas from the carbonization zone is then used to provide heat energy for the drying zone, thereby reducing the total energy consumption of the system;

[0051] (3) The gaseous products (drying tail gas) from the drying, carbonization and activation processes are used for catalytic decoking, deoxygenation combustion and activation combustion to generate high-temperature and high-humidity flue gas, which provides thermal energy for the activation zone and realizes energy self-supply;

[0052] (4) The circulation of the self-contained water vapor in the raw materials is utilized to provide an atmosphere with a high water vapor content for the activation zone, thus saving the use of water vapor. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0055] Figure 1 This is a process flow chart of the two-stage combustion method adopted in the present invention.

[0056] Figure 2 It is a schematic diagram of the recycling of self-contained water vapor in the present invention.

[0057] Figure 3 This is a process flow chart of the single-stage combustion method adopted in the present invention.

[0058] Figure 4 The present invention provides a schematic diagram of the structure of a device implemented by the method.

[0059] Among them: integrated rotary kiln 1, rotary kiln body 1-1, feeder 1-2, coke gas outlet 1-3, feed end 1-4, carbon discharge cabinet 1-5, carbon discharge cooler 1-6, activation zone 1-7, carbonization zone 1-8, drying zone 1-9, steam pipeline 1-10, rotary joint 1-11, steam inlet 1-12, steam valve 1-13, catalytic decoking device 2, high temperature shell 2-1, high temperature flue gas inlet 2-2, coke gas inlet 2-3, decoking outlet 2-4, mixer 2-5, catalyst partition 2-6, high temperature valve 2-7, solid-gas distributor 3, distribution air inlet 3-1 , gas outlet 3-2, decoking air outlet 3-3, spring-type pipeline 3-4, decoking air induced draft fan 4, gas combustion furnace 5, gas inlet 5-1, combustion air distribution fan 5-2, waste heat outlet 5-3, decoking outlet 5-4, activation outlet 5-5, waste heat boiler 5-6, deoxygenation burner 6, oxygen-containing inlet 6-1, fuel inlet 6-2, activation air outlet 6-3, mixing chamber 6-4, combustion chamber 6-5, outer shell 6-6, inner tube body 6-7, oxygen regulating valve 6-8, fuel valve 6-9, activation gas induced draft fan 7, activation burner 8, activation air distribution fan 8-2. DETAILED DESCRIPTION

[0061] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] Example 1

[0063] In this embodiment, a bamboo piece with a moisture content of 45% is taken as an example. Figure 1 , a two-stage burning process in an integrated drying, carbonization and activation method for preparing bamboo activated carbon is further described, including:

[0064] (1) Moisture content feeding: Take bamboo chips with a moisture content of 45% as raw material, without drying, and directly put the raw material into the integrated rotary kiln;

[0065] (2) Catalytic decoking: the drying tail gas of the integrated rotary kiln is introduced, and the temperature of the drying tail gas in this embodiment is 200°C; at the same time, the high-temperature flue gas of the combustion furnace is also introduced synchronously, and the temperature of the high-temperature flue gas in this embodiment is 1000°C; by controlling the decoking temperature, the drying tail gas is mixed and heated to 300-600°C; the drying tail gas includes about 55% of self-contained water vapor; Ni-CaO is preferably used as a catalyst to further crack the contained tar to form decoked gas; in this embodiment, the temperature of the decoked gas is 350°C;

[0066] (3) Gas distribution: The 350°C decoked gas is divided into two parts, one part of the decoked gas is used for activation combustion, and the other part of the decoked gas is used as fuel gas for high-temperature combustion. In this embodiment, about 60% of the decoked gas is used for activation combustion, and the remaining 40% of the decoked gas is used as fuel gas for high-temperature combustion.

[0067] (4) High-temperature combustion: The gas is fully burned with oxygen in a gas combustion furnace. In this embodiment, the combustion temperature is controlled to generate high-temperature flue gas of 1000°C. In this embodiment, 10% of the high-temperature flue gas is used for catalytic decoking, 15% of the high-temperature flue gas is used for activated combustion, and the remaining 75% of the high-temperature flue gas is led to the waste heat boiler to be converted into water vapor for energy recovery. The boiler tail gas is treated by environmental protection equipment and discharged after meeting the standards.

[0068] (5) Deoxygenated combustion: 40% of the decoked gas is drawn from the gas distribution link; then, the high-temperature flue gas is used as an oxidant and the decoked gas is used as a fuel for combustion; this combustion does not require additional air and is aimed at consuming the oxygen in the high-temperature flue gas; in this embodiment, the deoxygenated combustion temperature is controlled to be 600°C to 650°C, and activated gas of about 600°C is generated;

[0069] (6) Activated combustion: In this embodiment, activated gas at about 600°C is used as fuel, and air accounting for about 20% of the activated gas is added to carry out incomplete combustion. In this embodiment, high-humidity flue gas at 850°C is generated through activated combustion control, and the content of water vapor (self-contained water vapor) in the high-humidity flue gas is about 45%.

[0070] (7) Integrated activation: In this embodiment, high-humidity flue gas is introduced into the integrated rotary kiln to provide a high-temperature and high-humidity atmosphere with a temperature of more than 800°C and a water vapor content of more than 40% for the activation zone; in this embodiment, the carbonized material is retained under the atmosphere for about 2 hours to undergo a high-temperature activation reaction, thereby achieving a bamboo activated carbon with an iodine value of about 600 g / L; the bamboo activated carbon is cooled to room temperature and can be packaged; in this embodiment, the temperature of the activated tail gas of the activation reaction is about 600°C;

[0071] (8) Integrated carbonization: In this embodiment, the activated tail gas with a temperature of about 600°C enters the carbonization zone, providing an atmosphere of 600°C to 350°C for the carbonization zone; the dehydrated raw material gradually heats up under the atmosphere, is converted into carbonized material through carbonization reaction, and finally enters the activation zone; in this embodiment, the combustible components (mainly CO, H2, CH4 and tar) produced by the carbonization reaction are all contained in the carbonized tail gas, and the temperature of the carbonized tail gas is about 350°C;

[0072] (9) Integrated drying: In this embodiment, the carbonized tail gas with a temperature of about 350°C enters the drying zone, providing an atmosphere of 350°C to 200°C for the drying zone; the water-containing raw material is largely dehydrated under the atmosphere conditions and becomes a dry dehydrated raw material; the water in the raw material evaporates into self-contained water vapor, which is mixed into the carbonized tail gas to form a drying tail gas. In this embodiment, the drying tail gas has a temperature of 200°C, contains about 55% of self-contained water vapor, and has a combustion calorific value of about 10 MJ / m3.

[0073] In this embodiment, combined with the attached Figure 2 , the process of recycling the self-contained water vapor and the process of temperature change are further described in detail, including:

[0074] (1) Outside the integrated rotary kiln, the water vapor contained in the drying tail gas is at a temperature of 200°C; after passing through the catalytic decoking stage, the temperature rises to 350°C and gas distribution is carried out;

[0075] (2) Outside the integrated rotary kiln, the water vapor contained in the decoking gas has a temperature of 350°C; after passing through the deoxygenation combustion stage, the temperature rises to 600°C;

[0076] (3) Outside the integrated rotary kiln, the water vapor contained in the activated gas has a temperature of 600°C; after flowing through the activation combustion stage, the temperature rises to 850°C;

[0077] (4) Inside the integrated rotary kiln, the water vapor is contained in the high-humidity flue gas with a temperature of 850°C; after flowing through the integrated activation link, the temperature drops to 600°C;

[0078] (5) Inside the integrated rotary kiln, the water vapor contained in the activated tail gas has a temperature of 600°C; after flowing through the integrated carbonization stage, the temperature drops to 350°C;

[0079] (6) Inside the integrated rotary kiln, the self-contained water vapor is contained in the carbonization exhaust gas, and the temperature is 350°C; after flowing through the integrated drying stage, the temperature drops to 200°C; finally, the self-contained water vapor is re-contained in the decoking gas, and this cycle is repeated, forming a recycling process and a temperature cycle.

[0080] Example 2

[0081] In this embodiment, a bamboo piece with a moisture content of 30% is taken as an example. Figure 3 , a single-stage burning process in an integrated drying, carbonization and activation method for preparing bamboo activated carbon is further described, including:

[0082] (1) Moisture content feeding: Take bamboo chips with a moisture content of 30% as raw materials, without drying, and directly put the raw materials into the integrated rotary kiln;

[0083] (2) Catalytic decoking: The process is similar to the catalytic decoking process in Example 1, except that in this embodiment, the drying tail gas contains about 40% of self-contained water vapor;

[0084] (3) Gas distribution: the same as the gas distribution process in Example 1;

[0085] (4) High temperature combustion: the same as the high temperature combustion step in Example 1;

[0086] (5) Activated combustion: In this embodiment, decoking gas at about 350°C is used as fuel, and air accounting for about 30% of the activated gas is added to carry out incomplete combustion. In this embodiment, activated combustion control is carried out to generate high-humidity flue gas at 850°C, in which the content of water vapor (self-contained water vapor) is about 35%.

[0087] (6) Integrated activation: This step is similar to the integrated activation step in Example 1, except that in this embodiment, the water vapor content in the activation zone atmosphere is about 30% or more, and the carbonized material is retained under this atmosphere for about 2.5 hours;

[0088] (7) Integrated carbonization: the same as the integrated carbonization step in Example 1;

[0089] (8) Integrated drying: This step is similar to the integrated drying step in Example 1, except that in this embodiment, the drying exhaust gas contains about 40% of self-contained water vapor, and its combustion calorific value is about 15 MJ / m3.

[0090] Example 3

[0091] The present invention provides a drying, carbonization, and activation integrated method for preparing bamboo activated carbon, which can be achieved through a specific device; a drying, carbonization, and activation integrated device for preparing bamboo activated carbon, this embodiment is combined with the attached Figure 4 To further elaborate:

[0092] An integrated rotary kiln 1, the integrated rotary kiln 1 has a rotary kiln shape, including: a rotary kiln body 1-1, a feeder 1-2, a coke gas outlet 1-3, a feed end 1-4, a charcoal discharge cabinet 1-5, and a charcoal discharge cooler 1-6; the feeder 1-2 is in the form of a spiral feeder, with an outer dimension of Φ0.5m×3m, installed on the feed end 1-4. The raw material is bamboo chips with a moisture content of 45%, which enter the rotary kiln body 1-1 from the feeder 1-2 at a feeding rate of 3t / h; the rotary kiln body 1-1 is a rotary kiln with an outer dimension of Φ2m×18m, and is wrapped with 100mm insulation cotton on the outside; the coke gas outlet 1-2 is a circular opening of Φ0.6m, which is opened just above the feed end 1-4 to discharge the coke gas. The coke-containing gas here is the drying tail gas described in the present invention; the feed end 1-4 is a cavity arranged on the feeding side of the rotary kiln body 1-1, and is a cone with an outer dimension of Φ2m×1m, which is used to collect gaseous products; the carbon discharging cabinet 1-5 uses a square cabinet of 2.5m×2.5m×1m, which is arranged on the discharging side of the rotary kiln body 1-1; the carbon discharging cooler 1-6 uses a U-shaped spiral discharging device with double water cooling of the outer shell and the central axis, with an outer dimension of Φ0.7m×4m, which is arranged at the bottom of the carbon discharging cabinet 1-5, and is used to cool and discharge the prepared activated carbon; the inside of the rotary kiln body 1-1, the temperature above 800℃ is the activation zone 1-7, the temperature of 450℃~800℃ is the carbonization zone 1-8, and the temperature of 250℃~450℃ is the drying zone 1-9; the internal gas of the rotary kiln body 1-1 flows from the activation zone 1-7 to the drying zone 1-9. In this embodiment, the temperature of the coke-containing gas is 200°C and is drawn out from the coke-containing gas outlet 1-3. On the outside of the rotary kiln body 1-1, there are also 8 parallel water vapor pipes 1-10 with an axial diameter of 6 inches; the above-mentioned water vapor pipes 1-10 are all interconnected and connected to the waste heat boiler 5-6 through a 1-inch rotary joint 1-11; each of the water vapor pipes 1-10 is provided with 10 evenly distributed steam inlets 1-12, all of which are inserted into the activation zone 1-7; in order to control the amount of water vapor replenishment, each of the water vapor pipes 1-10 is provided with an electromagnetic steam valve 1-13. When the moisture content of the raw material is lower than 30%, the steam valve is opened to replenish water vapor;

[0093] A catalytic decoking device 2, the catalytic decoking device 2 comprises: a high-temperature shell 2-1, a high-temperature flue gas inlet 2-2, a coke-containing gas inlet 2-3, and a decoking outlet 2-4; the high-temperature shell 2-1 is a Φ1.5m×3m stainless steel cylinder, and the outside is wrapped with thermal insulation cotton; the high-temperature flue gas inlet 2-2 is built with high-temperature refractory bricks, with an inner cross-section of 0.4m×0.4m, and is opened on the side of the high-temperature shell 2-1; the coke-containing gas inlet 2-3 is a Φ0.6m circular hole, which is opened at the bottom of the high-temperature shell 2-1; the decoking outlet 2-4 adopts a conical design, with an outer size of Φ1.5m×1m, and a cone top opening The outlet is Φ0.5m; a mixer 2-5 is also provided in the high-temperature shell 2-1; the mixer 2-5 is a hollow circular tube of Φ0.7m×1m, and 16 propeller blades are evenly arranged between the outside of the circular tube and the high-temperature shell 2-1, and an array of 500 Φ20mm nozzles is provided on the surface of the circular tube for fully mixing the coke-containing gas and the high-temperature flue gas; a 100mm thick catalyst partition is also provided on the outlet side of the high-temperature shell 2-1, which is made of Ni-CaO catalyst material, and the catalyst partition is provided with an array of more than 1000 honeycomb pores with a diameter less than Φ10mm. A high-temperature valve 2-7 with a temperature resistance of more than 1000°C and an inner cross-section of 0.5m×0.5m is provided outside the high-temperature flue gas inlet 2-2 to control the proportion of the high-temperature flue gas entering and adjust the temperature of the decoked gas. In this embodiment, the temperature of the decoked gas is 350°C;

[0094] A solid-gas distributor 3, the solid-gas distributor 3 comprises: a distribution air inlet 3-1, a fuel gas outlet 3-2, and a decoking air outlet 3-3; in this embodiment, the solid-gas distributor 3 adopts a spring-type pipeline 3-4 structure, the inner cross-section of the pipeline is Φ0.6m, the outer diameter of the spring is Φ2m, and a total of 10 layers are arranged; the inlet of the spring-type pipeline 3-4 is the distribution air inlet 3-1 for introducing decoking gas, and its diameter is Φ0.6m; the outlet is the decoking air outlet 3-3 for activated combustion, and its diameter is also Φ0.6m; in the spring-type pipeline 3-4, 100 Φ0.05m pores are evenly opened on the inner wall of each layer; the central area of ​​the spring-type pipeline 3-4 is closed, and an outlet with a diameter of Φ0.6m is set as the fuel gas outlet 3-2 for high-temperature combustion; in this embodiment, the temperature of the decoking gas and the fuel gas is 350°C;

[0095] A decoking air induced draft fan 4, which is a 304 stainless steel centrifugal fan with a flow rate of 20000m3 / h, a total pressure of 2000Pa, and a temperature resistance of 400°C; the decoking air induced draft fan is placed between the decoking air outlet 2-4 and the distribution air inlet 3-1;

[0096] A gas combustion furnace 5, wherein the gas combustion furnace 5 adopts a cylindrical furnace structure with an outer size of Φ2.5m×6m, a layer of high-temperature resistant bricks and a layer of insulation bricks are laid inside, and a layer of 100mm thick body temperature cotton is wrapped around the outer shell; the gas combustion furnace 5 comprises: a gas inlet 5-1, a combustion air distribution fan 5-2, a waste heat outlet 5-3, a decoking outlet 5-4 and an activation outlet 5-5; the gas inlet 5-1 is a 304 stainless steel pipe with a diameter of Φ0.6m, and is connected to the gas outlet 3-2; the waste heat outlet 5-3, the decoking outlet 5-4 and the activation outlet 5-5 are all built with high-temperature refractory bricks, and the inner cross-section is 0.5m×0.5m; wherein the waste heat outlet 5-3 is connected to a 6t / h, 0.8MPa waste heat boiler 5-6, which generates 8 kg of high-pressure steam for users; the decoking outlet 5-4 is connected to the high-temperature flue gas inlet 2-2;

[0097] A deoxygenation burner 6, the deoxygenation burner 6 comprises: an oxygen-containing gas inlet 6-1, a fuel inlet 6-2, and an activated gas outlet 6-3; the oxygen-containing gas inlet 6-1 is made of high-temperature refractory bricks, and the inner cross-section is 0.5m×0.5m, connected to the activated gas outlet 5-5 to introduce high-temperature flue gas; the fuel inlet 6-2 is a 304 stainless steel pipe with a diameter of Φ0.6m, connected to the carbon-containing gas outlet 3-3; the deoxygenation burner 6 adopts a mixing chamber 6-4 and a combustion chamber The front and rear double chamber structure of 6-5 has an outer size of Φ1.5m×4m stainless steel cylinder, wherein the length of the mixing chamber 6-4 is 2m, and the length of the combustion chamber 6-5 is 2m; the mixing chamber 6-4 adopts an inner and outer double-layer structure: the size of the outer shell 6-6 is Φ1.5m×2m carbon steel cylinder, and the outside is wrapped with 100mm insulation cotton; the inner tube body 6-7 is a Φ0.8m×2m hollow round tube, with more than 500 Φ10mm pores evenly distributed on it, so that the high-temperature smoke The gas can enter the inner tube body 6-6 through the pores; the outer shell 6-6 is connected to the oxygen-containing inlet 6-1; the inner tube body 6-7 is connected to the fuel inlet 6-2 and inserted into the outer shell 6-6; in the inner tube body 6-7, the high-temperature flue gas and the carbon-containing gas are mixed and sprayed into the combustion chamber 6-5 for combustion; the combustion chamber 6-5 is a conical structure with an outer diameter of Φ1.5m and a cone height of 2m, and is cast with high-temperature refractory materials inside. An activated gas outlet 6-3 with an outer diameter of Φ0.6m is provided at the top of the cone; an oxygen regulating valve 6-8 with a temperature resistance of more than 1000°C and an inner cross-section of 0.5m×0.5m is provided outside the oxygen-containing inlet 6-1; a butterfly valve with a diameter of Φ0.6m is provided outside the fuel inlet 6-2 as a fuel valve 6-9; the temperature of the activated gas is adjusted by the opening of the oxygen regulating valve 6-8 and the fuel valve 6-9; in this embodiment, the temperature of the drawn activated gas is 600°C;

[0098] An activated air induced draft fan 7, which uses a 304 stainless steel high-temperature centrifugal fan with a flow rate of 30000m3 / h, a total pressure of 2000Pa, and a temperature resistance of 800°C; the air inlet of the activated air induced draft fan 7 is connected to the activated air outlet 6-3; the air outlet of the activated air induced draft fan 7 is connected to the activated burner 8 to provide fuel for the activated burner 8.

[0099] The activation burner 8 uses a 900,000 kcal gas burner, and the blower is equipped with a 10KW frequency converter for independent control; the activation burner 8 is installed in the middle of the charcoal cabinet 1-5, and the flame outlet is facing the center line of the rotary kiln body 1-1; the temperature of the high-humidity flue gas generated by the activation burner 8 is 850°C;

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drying, carbonization and activation integrated method for preparing bamboo activated carbon, characterized in that: include: (1) Feeding with water: Take biomass raw materials with a moisture content greater than 30%, and directly feed the raw materials with water into the integrated rotary kiln without drying; (2) Catalytic decoking: The drying tail gas of the integrated rotary kiln is introduced, and the high-temperature flue gas of the combustion furnace is also introduced simultaneously, and the decoking temperature is controlled at the same time, so that the drying tail gas is mixed and heated to a medium temperature; the tar contained in the drying tail gas is fully cracked under the action of the self-contained water vapor and the catalyst to form decoked gas; the drying tail gas is a gaseous product of the drying, carbonization and activation process, has a low temperature, is flammable and rich in tar and self-contained water vapor; the temperature of the decoked gas is medium temperature; (3) Gas distribution: the decoking gas is divided into two parts, one part of the decoking gas is used for activation combustion, and the other part of the decoking gas is used as fuel gas for high-temperature combustion. In principle, the activation combustion is first satisfied, and the excess is then distributed to the high-temperature combustion. (4) High-temperature combustion: The gas is fully burned with oxygen in a gas combustion furnace, and the combustion temperature is controlled to generate high-temperature flue gas; a portion of the high-temperature flue gas is used for catalytic decoking and activation combustion, and the excess high-temperature flue gas is led out to the waste heat utilization equipment for energy recovery, and its tail gas is discharged; (5) Activated combustion: converting the decoking gas distributed from the fuel gas into high-humidity flue gas; the high-humidity flue gas is a gaseous product of the activated combustion, has a high temperature, has an oxygen content of zero and contains a large amount of self-contained water vapor; (6) Integrated activation: The high-humidity flue gas is introduced into the integrated rotary kiln to provide a high-temperature, high-water vapor content atmosphere and heat source for the activation zone of the integrated rotary kiln; the carbonized material undergoes an activation reaction under the atmosphere conditions, the solid product is activated carbon, and the gaseous product is activated exhaust gas; the activated carbon is cooled to room temperature by a cooler and packaged. (7) Integrated carbonization: The activated tail gas then enters the carbonization zone of the integrated rotary kiln, providing a sub-high temperature atmosphere and heat source for the carbonization zone; the dehydrated raw material undergoes a carbonization reaction under the atmosphere, the solid product is the carbonized material, and the gaseous product is the carbonized tail gas; (8) Integrated drying: The carbonized tail gas then enters the drying zone of the integrated rotary kiln, providing a medium-temperature atmosphere and heat source for the drying zone; the water-containing raw material is dried and dehydrated under the atmosphere, the solid product is the dehydrated raw material, and the gaseous product is the drying tail gas.

2. The drying, carbonization and activation integrated method for preparing bamboo activated carbon according to claim 1, characterized in that: The activated combustion may adopt a single-stage combustion mode or a two-stage combustion mode; The single-stage combustion method refers to directly introducing the decoked gas into the burner, and then adding a small amount of air for incomplete combustion; at the same time, directly performing activation combustion control to generate high-temperature and high-humidity flue gas; The two-stage combustion method refers to adding deoxygenation combustion to the single-stage combustion method, that is, deoxygenation combustion is performed first and then activation combustion is performed; the deoxygenation combustion refers to combustion using the high-temperature flue gas as an oxidant and the decoking gas as fuel, with the goal of consuming the oxygen in the high-temperature flue gas; at the same time, deoxygenation combustion control is performed to make the combustion temperature sub-high temperature, and the combustion product is activated gas; the activated gas is an oxygen-free gas containing self-contained water vapor and combustible components; the activation combustion under the two-stage combustion method refers to using the activated gas as fuel and adding a small amount of air for incomplete combustion; at the same time, activation combustion control is performed to produce high-temperature and high-humidity flue gas.

3. The drying, carbonization and activation integrated method for preparing bamboo activated carbon according to claim 1, characterized in that: The high temperature is above 800°C, the sub-high temperature is between 450°C and 800°C, the medium temperature is between 250°C and 450°C, and the low temperature is below 250°C.

4. The drying, carbonization and activation integrated method for preparing bamboo activated carbon according to claim 1, characterized in that: The water vapor required for the integrated activation comes from the self-contained water vapor; the self-contained water vapor is the water vapor formed by the raw materials and the water carried therein.

5. The drying, carbonization and activation integrated method for preparing bamboo activated carbon according to claim 4, characterized in that: The self-contained water vapor is recycled.

6. The drying, carbonization and activation integrated method for preparing bamboo activated carbon according to claim 1, characterized in that: The high temperature required for the integrated activation comes from the combustible components in the drying exhaust gas.

7. The drying, carbonization and activation integrated method for preparing bamboo activated carbon according to claim 1, characterized in that: The self-contained water vapor is heated outside the integrated rotary kiln and cooled inside the integrated rotary kiln.

8. The drying, carbonization and activation integrated method for preparing bamboo activated carbon according to claim 1, characterized in that: The integrated drying, the integrated carbonization and the integrated activation are integrated in an integrated rotary kiln.

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