In-situ and ex-situ catalytic pyrolysis device with movable heating area and pyrolysis method

Abstract

The invention relates to an in-situ and ex-situ catalytic pyrolysis device with a movable heating area and a pyrolysis method. The in-situ and ex-situ catalytic pyrolysis device comprises a rack; the reaction tube is axially and horizontally arranged on the rack; the left end of the reaction tube is communicated with a nitrogen cylinder through a rotary joint, a flow meter and a pressure reducing valve; the first end of the three-way pipe is connected with the right end of the reaction pipe through a rotary joint, the second end of the three-way pipe is connected in series with the first condenser and the first gas storage bag through a first stop valve, and the third end of the three-way pipe is connected in series with the second condenser and the second gas storage bag through a second stop valve; the tubular heating furnace is horizontally arranged on the rack in a sliding manner along the axial direction of the reaction tube, and a first heating area and a second heating area which are different in temperature are arranged in the tubular heating furnace; according to the device, on the basis that the in-situ catalytic reaction and the ex-situ catalytic reaction are carried out in the same device, the influence of the heating rate on the rapid pyrolysis of the raw materials is avoided, the full contact between different raw materials in the co-pyrolysis process and the maximum production of target products are ensured, and a catalyst evaluation function is also considered.

Description

Technical Field

[0001] This invention relates to the field of catalytic pyrolysis, and in particular to in-situ and non-in-situ catalytic pyrolysis apparatus and methods with movable heating zones. Background Technology

[0002] Resource utilization technologies for organic solid waste (agricultural and forestry waste, plastic waste, etc.) have the dual benefits of alleviating energy shortages and promoting environmental protection, and have become a current research hotspot. Bio-oil prepared by co-pyrolysis of biomass and plastics has high calorific value, low oxygen content, and high hydrocarbon content, making it an effective means of directional thermal conversion to produce high-value chemicals. The key to the synergistic effect between biomass and waste plastics lies in the overlapping thermal weight loss temperature ranges of the different components after mixing, allowing the primary products generated by pyrolysis to come into contact with each other. This often requires the addition of a catalyst during co-pyrolysis. In-situ catalysis (direct contact between raw materials and catalyst) allows for effective control at the pyrolysis source, resulting in good catalyst performance; however, the raw materials and catalyst cannot be separated, and the catalyst is prone to coking and deactivation. In non-in-situ catalysis (where the raw materials and catalyst do not come into direct contact), the catalyst can be recovered and reused multiple times, but it is mainly used for directional reforming of primary pyrolysis products from co-pyrolysis, with poor source control effects. In experiments, it is often necessary to compare in-situ and non-in-situ catalysis to find the experimental method that maximizes the preparation of the target product, and the catalyst lifetime needs to be evaluated. Furthermore, the heating rate is a crucial factor affecting the pyrolysis reaction. Current fixed-bed pyrolysis devices typically have a heating rate of 0-20℃ / min, while rapid pyrolysis for oil production usually requires reaction conditions of 500-700℃. A slower heating rate means that the volatiles in the feedstock have already partially decomposed before reaching the target reaction temperature, which significantly affects the efficiency of the catalytic co-pyrolysis reaction, resulting in a lower yield of the target product. In addition, feedstocks such as biomass usually need to undergo drying pretreatment before the pyrolysis reaction to remove moisture; the reactor also needs to be insulated in the direction of gaseous bio-oil outflow to prevent the bio-oil from condensing into a liquid state and clogging the pipeline at low temperatures.

[0003] In summary, how to achieve in-situ and ex-situ catalysis in the same reaction device, effectively eliminate the influence of thermal decomposition of raw materials on the target product during the process of heating to the target reaction temperature, and take into account the function of catalyst evaluation has become an urgent problem for researchers in this field. Summary of the Invention

[0004] To address the aforementioned issues, this application discloses a two-stage movable heating zone biomass and plastic in-situ / non-in-situ catalytic pyrolysis device. This device, while ensuring thorough mixing between different raw materials and between the raw materials and the catalyst, enables in-situ and non-in-situ catalysis to occur simultaneously within the same reaction unit. It effectively eliminates the impact of raw material thermal decomposition on the target product during the heating process to the target reaction temperature, while also accommodating catalyst evaluation. Furthermore, raw material drying and pyrolysis can be carried out within the same reaction unit, and the waste heat from drying can be recovered and used to insulate the pipelines.

[0005] Specifically, the technical solution adopted by this invention is as follows: This invention relates to an in-situ and non-in-situ catalytic pyrolysis device with a movable heating zone, comprising: a frame; a reaction tube, which is horizontally mounted on the frame and rotates about its axis by a rotating assembly; a nitrogen cylinder, the left end of which is connected to the nitrogen cylinder via a rotary joint, a flow meter, and a pressure reducing valve; a three-way pipe, the first end of which is connected to the right end of the reaction tube via a rotary joint, the second end of which is connected in series with the first condenser and the first gas storage bag via a first shut-off valve, and the third end of which is connected in series with the second condenser, a moisture removal device, and the second gas storage bag via a second shut-off valve; a tubular heater, which is horizontally slidably mounted on the frame along the axis of the reaction tube, the reaction tube passing horizontally through the tubular heater, and the tubular heater containing a first heating zone and a second heating zone with different temperatures; and a temperature controller mounted on the tubular heater for controlling the heating temperature of the first heating zone or the second heating zone.

[0006] Furthermore, a catalyst addition device is provided on the side of the reaction tube near the right end of the reaction tube, and the catalyst addition device is filled with catalyst.

[0007] This application also discloses a pyrolysis method using an in-situ and non-in-situ catalytic pyrolysis device with a movable heating zone. When in-situ experiments are required, the method includes the following steps: S1: Mix the raw materials formed from biomass and waste plastics with the catalyst in a certain proportion and then put them into the reaction tube; S2: Nitrogen gas is introduced into the reaction tube from the nitrogen cylinder to purge the air from the reaction tube; S3: A mobile tubular heater that heats and dehydrates the raw material in the first heating zone located inside the reaction tube. The first shut-off valve is opened and the second shut-off valve is closed. The generated gas enters the first gas storage bag from the first condenser, while the steam continuously insulates the pipeline. S4: A mobile tubular heater is used to pyrolyze the raw material in the second heating zone inside the reaction tube. The second shut-off valve is opened and the first shut-off valve is closed. The generated gas is condensed from the second condenser to obtain the bio-oil ratio. The gas is collected by the second gas storage bag to obtain the biomass gas ratio. The difference between the raw material before and after the reaction is used to obtain the biochar ratio. S5: Move the tubular furnace to a non-raw material location and turn off the heating. Cool the raw material in the reaction tube to room temperature. The reaction is then complete.

[0008] This application also discloses a pyrolysis method using an in-situ and non-in-situ catalytic pyrolysis device with a movable heating zone. When a non-in-situ experiment is required, the method includes the following steps: A1: After mixing biomass and waste plastics in a certain proportion, the raw materials are put into the reaction tube. The catalyst is then filled into the catalyst addition device and installed on the right side of the reaction tube. A2: Nitrogen gas is introduced into the reaction tube from the nitrogen cylinder to purge the air from the reaction tube; A3: A mobile tubular heating furnace, which heats and dehydrates the raw material in the first heating zone inside the reaction tube, opens the first shut-off valve and closes the second shut-off valve, and at the same time, the generated gas enters the first gas storage bag from the first condenser, while the steam continuously insulates the pipeline. A 4: A mobile tubular heater is used to pyrolyze the raw material in the second heating zone inside the reaction tube. The second shut-off valve is opened and the first shut-off valve is closed. The generated gas is condensed in the second condenser to obtain the bio-oil ratio. The gas is collected by the second gas storage bag to obtain the biomass gas ratio. The difference between the raw material before and after the reaction is used to obtain the biochar ratio. A5: Move the tubular furnace to a non-raw material location and turn off the heating. Cool the raw material in the reaction tube to room temperature. The reaction is then complete.

[0009] The beneficial effects of this invention are as follows: This invention is an in-situ and non-in-situ catalytic pyrolysis device and method with a movable heating zone. This device can achieve in-situ and non-in-situ catalytic reactions in the same device, while avoiding the influence of heating rate on the rapid pyrolysis of raw materials. It ensures sufficient contact between different raw materials and maximizes the production of target products during co-pyrolysis, and also takes into account the function of catalyst evaluation. The drying and pyrolysis of raw materials can be carried out in the same reaction device, and the waste heat from drying can be recovered and the pipeline can be insulated. In addition, by making full use of organic solid waste (agricultural and forestry waste, plastic waste) and combining in-situ / non-in-situ catalytic pyrolysis with two-stage movable heating zones (first heating zone and second heating zone), the product distribution of pyrolysis oil can be directionally controlled to achieve the resource and energy utilization of organic solid waste. Attached Figure Description

[0010] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0011] Figure 1 This is a schematic diagram of the structure of the present invention and an enlarged view of the catalyst addition device. Detailed Implementation

[0012] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0013] See Figure 1 This application discloses a pyrolysis apparatus, comprising: a frame 1; a reaction tube 2 axially and horizontally mounted on the frame 1, and controlled by a rotating assembly to rotate around its axis. During the reaction, the raw materials and catalyst are rotated along with the rotation of the reaction tube 2, improving the efficiency of drying and pyrolysis; the left end of the reaction tube 1 is connected to the nitrogen cylinder 6 through a rotary joint 3, a flow meter 4, and a pressure reducing valve 5. Before the reaction, nitrogen is continuously introduced into the reaction tube 2 to purge other gases from the reaction tube 2; during the reaction, nitrogen is continuously introduced into the reaction tube 2 to ensure that no other gases participate in the reaction. The first end of the three-way pipe 7 is connected to the right end of the reaction pipe 2 via a rotary joint 3. The second end of the three-way pipe 7 is connected in series with the first condenser 82 and the first gas storage bag 83 via a first shut-off valve 81. The third end of the three-way pipe 7 is connected in series with the second condenser 92, the moisture removal device 93, and the second gas storage bag 94 via a second shut-off valve 91. When nitrogen enters the reaction pipe 2 for purging or when the raw material is dried, the gas generated during drying is collected by the first gas storage bag 83 via the first end, the second end of the three-way pipe 7, and the first condenser 82. When the raw material is pyrolyzed, the generated gas is collected by the second gas storage bag 94 via the first end, the third end of the three-way pipe 7, and the second condenser 92. Experimental data are obtained by measuring the mass difference of the pyrolyzed raw material, the content of the gas collected by the second gas storage bag 94, and the mass difference of the second condenser 92. A tubular heating furnace 10 is horizontally slidably mounted on the frame 1 along the axial direction of the reaction tube 2. The reaction tube 2 passes horizontally through the tubular heating furnace 10. The tubular heating furnace 10 is provided with a first heating zone 11 and a second heating zone 12 with different temperatures. A temperature controller 13 is mounted on the tubular heating furnace 10 and is used to control the heating temperature of the first heating zone 11 or the second heating zone 12. When it is necessary to dry the raw material, the first heating zone 11 is moved to the raw material to dry it. When it is necessary to pyrolyze the raw material, the second heating zone 12 is moved to the raw material to pyrolyze it. In this way, the device can achieve both in-situ and ex-situ catalytic reactions in the same device, while avoiding the impact of heating rate on the rapid pyrolysis of raw materials. This ensures sufficient contact between different raw materials during co-pyrolysis and maximizes the production of the target product, while also taking into account the catalyst evaluation function. In addition, the gas generated during the drying of raw materials can insulate the pipeline, preventing the gas generated during the pyrolysis drying process from condensing with the pipeline and causing blockage.

[0014] See Figure 1 When the device needs to perform a non-in-situ reaction, a catalyst addition device 21 is provided on the side of the reaction tube near the right end of the reaction tube, and the catalyst addition device 21 is filled with catalyst. In this embodiment, since the raw materials do not come into contact with the catalyst during non-in-situ reactions, the gas generated by pyrolysis passes through the catalyst addition device 21 filled with catalyst to catalyze the pyrolysis of the raw materials. The outer diameter of the catalyst addition device 21 is sealed to the inner diameter of the reaction tube 2, and the catalyst addition device 21 is a hollow cylinder with several holes on the left and right sides. The diameter of the holes is smaller than the diameter of the raw materials and the catalyst.

[0015] This application also discloses the following embodiments; Example 1: During the in-situ reaction, biomass and plastic are thoroughly mixed in a 1:1 ratio to form the raw material. The raw material and catalyst are then thoroughly mixed in a 1:5 ratio. The biomass, plastic, and catalyst are evenly placed in the reaction tube 2, ensuring uniformity along the entire length of the tube and a height exceeding one-third of the tube's diameter. Nitrogen gas is introduced for 20 minutes to purge air from the tube furnace. At the start of the reaction, the first heating zone 11 is raised to 105°C and moved to completely cover the raw material, which is then positioned within the first heating zone 11 for dehydration and drying. The first shut-off valve 81 is opened, and the second shut-off valve 91 is closed. The airflow generated during drying heats and maintains the temperature of the pipeline through the reaction tube 2. Set the heat preservation time to 12 hours; close the first heating zone 11, raise the temperature of the second heating zone 12 to 600℃, open the second shut-off valve 91, close the first shut-off valve 81, and the second heating zone 12 completely covers the raw material position, and at this time the raw material is located in the second heating zone 12. Adjust the rotation speed of the reaction tube 2 to 5 r / min by rotating the component, and react for 30 minutes to carry out the pyrolysis reaction. After the reaction is completed, turn off the power switch, move the tubular heater 10 to a position where no raw material is covered, and cool it to room temperature. The reaction ends. The biochar yield is 28.86%, the biomass gas yield is 15.12%, the bio-oil yield is 56.02%, and the aromatic hydrocarbon content in the bio-oil is 24.36%.

[0016] The biochar yield is obtained from the mass difference of the pyrolysis feedstock, the biomass gas yield is obtained from the content of the gas collected in the second gas storage bag 94, the bio-oil yield is obtained from the mass difference of the second condenser 92, and the proportion of aromatic hydrocarbons in the bio-oil is obtained by subsequent detection components. Specifically, the gas released from the pyrolysis of the feedstock is condensed in the second condenser 93, and the non-condensable gas enters the second gas storage bag 94. After the furnace body is separated from the feedstock, the collection of gas and liquid is stopped, and nitrogen is continued to be introduced until the temperature of the tubular heater 10 drops to room temperature. The biochar yield is determined by the weight of biomass and waste plastics before and after the reaction, the bio-oil yield is calculated from the weight of the second condenser 93 before and after the reaction, and the gas yield is calculated using the difference method.

[0017] Example 2: When performing an in-situ reaction, the catalyst is placed in the catalyst addition device and filled with it. The catalyst-to-raw material ratio is 5:1, and the biomass-to-plastic ratio is 1:1. The biomass and plastic are thoroughly mixed to form the raw material. The biomass and plastic are evenly placed on the left side of the reaction tube 2, ensuring uniformity along the entire length of the reactor, with a height exceeding 1 / 3 of the reaction tube diameter. The catalyst is placed on the right side of the reaction tube. After sealing the system, nitrogen gas is introduced for 20 minutes to purge the air from the reaction tube 2. The reaction begins, and the first heating zone 11 is raised to 105°C and moved to a position that completely covers the raw material. At this time, the raw material is located in the first heating zone 11, and a dehydration and drying reaction is carried out. The first shut-off valve 81 is opened, and the second shut-off valve 91 is closed. The dried product... The gas flow heats and maintains the temperature of the pipeline through reaction tube 2 for 12 hours. The first heating zone 11 is then closed, and the temperature of the second heating zone 12 rises to 600℃. The second shut-off valve 91 is opened, and the first shut-off valve 81 is closed, ensuring the second heating zone 12 completely covers the raw material. The raw material is then positioned within the second heating zone 12. The rotating assembly adjusts the rotation speed of reaction tube 2 to 5 r / min, and the reaction proceeds for 30 minutes to complete the pyrolysis reaction. After the reaction is complete, the power switch is turned off, and the tubular furnace 10 is moved to a location where no raw material is covered, allowing it to cool to room temperature. The reaction is then complete. The biochar yield is 29.52%, the biogas yield is 14.96%, and the bio-oil yield is 55.52%, with aromatic hydrocarbons comprising 20.53% of the bio-oil.

[0018] Example 3: The catalyst is placed in the catalyst addition device and filled with a catalyst:raw material ratio of 5:1. Biomass:plastic is thoroughly mixed in a 1:1 ratio to form the raw material. The biomass and plastic are evenly placed in the reaction tube 2, ensuring uniformity along the entire length of the reactor, with a height exceeding 1 / 3 of the reaction tube diameter. Nitrogen gas is introduced for 20 minutes to purge air from the reaction tube. The reaction begins, and the first heating zone 11 is raised to 105°C and moved to completely cover the raw material, with the raw material now located in the first heating zone 11, for dehydration and drying. The first shut-off valve 81 is opened, and the second shut-off valve 91 is closed. The airflow generated during drying heats and maintains the temperature of the pipeline through the reaction tube 2 for 12 hours. The first heating zone 11 is closed, and the temperature of the second heating zone 12 is raised to 600°C. The second shut-off valve 91 is opened, and the first shut-off valve 81 is closed. The second heating zone 12 completely covers the raw material, and the raw material is now located in the first heating zone 12. The material was located at position 12 in the second heating zone. The rotating component adjusted the rotation speed of the reaction tube to 5 r / min, and the reaction was carried out for 30 minutes for pyrolysis. After the reaction was completed, the power switch was turned off, and the tubular heater 10 was moved to a position where no raw material was covered to cool down to room temperature. The reaction ended. Multiple experiments were conducted under completely identical experimental conditions without replacing the catalyst. After the first reaction, the proportion of aromatic hydrocarbons in the bio-oil was 20.53%, after the second reaction, the proportion of aromatic hydrocarbons in the bio-oil was 9.32%, and after the third reaction, the proportion of aromatic hydrocarbons in the bio-oil was 2.96%, which is close to the catalytic co-pyrolysis of biomass and plastic without catalyst. This indicates that the catalyst is basically deactivated after being reused for the third time, thus realizing the function of catalyst evaluation. Non-in-situ catalytic reaction can also take into account the function of catalyst evaluation, that is, the catalyst is added and the device is not moved. Multiple experiments are carried out under the same experimental conditions, and the number of times the catalyst can be reused is examined from the product distribution.

[0019] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An in-situ and non-in-situ catalytic pyrolysis device with a movable heating zone, characterized in that, include: frame; The reaction tube is horizontally mounted on the frame and rotates about its axis by a rotating assembly. A nitrogen cylinder is connected to the left end of the reaction tube via a rotary joint, a flow meter, and a pressure reducing valve. The three-way pipe has its first end connected to the right end of the reaction tube via a rotary joint, its second end connected in series with the first condenser and the first gas storage bag via a first shut-off valve, and its third end connected in series with the second condenser, the moisture removal device, and the second gas storage bag via a second shut-off valve. A tubular heating furnace is horizontally slidably mounted on the frame along the axial direction of the reaction tube. The reaction tube passes horizontally through the tubular heating furnace, and the tubular heating furnace is provided with a first heating zone and a second heating zone with different temperatures. A temperature controller is installed on the tubular furnace and is used to control the heating temperature of the first heating zone or the second heating zone.

2. The in-situ and non-in-situ catalytic pyrolysis device with a movable heating zone according to claim 1, characterized in that, A catalyst addition device is provided on the side of the reaction tube near the right end of the reaction tube, and the catalyst addition device is filled with catalyst.

3. A pyrolysis method, comprising an in-situ or non-in-situ catalytic pyrolysis apparatus with a movable heating zone as described in any one of claims 1-2, characterized in that, When in-situ experiments are required, the following steps are included: S1: Mix the raw materials formed from biomass and waste plastics with the catalyst in a certain proportion and then put them into the reaction tube; S2: Nitrogen gas is introduced into the reaction tube from the nitrogen cylinder to purge the air from the reaction tube; S3: A mobile tubular heater that heats and dehydrates the raw material in the first heating zone located inside the reaction tube. The first shut-off valve is opened and the second shut-off valve is closed. The generated gas enters the first gas storage bag from the first condenser, while the steam continuously insulates the pipeline. S4: A mobile tubular heater is used to pyrolyze the raw material in the second heating zone inside the reaction tube. The second shut-off valve is opened and the first shut-off valve is closed. The generated gas is condensed from the second condenser to obtain the bio-oil ratio. The gas is collected by the second gas storage bag to obtain the biomass gas ratio. The difference between the raw material before and after the reaction is used to obtain the biochar ratio. S5: Move the tubular furnace to a non-raw material location and turn off the heating. Cool the raw material in the reaction tube to room temperature. The reaction is then complete.

4. A pyrolysis method, comprising an in-situ or non-in-situ catalytic pyrolysis apparatus with a movable heating zone as described in any one of claims 1-2, characterized in that, When non-in-situ experiments are required, the following steps are included: A1: After mixing biomass and waste plastics in a certain proportion, the raw materials are put into the reaction tube. The catalyst is then filled into the catalyst addition device and installed on the right side of the reaction tube. A2: Nitrogen gas is introduced into the reaction tube from the nitrogen cylinder to purge the air from the reaction tube; A3: A mobile tubular heating furnace, which heats and dehydrates the raw material in the first heating zone inside the reaction tube, opens the first shut-off valve and closes the second shut-off valve, and at the same time, the generated gas enters the first gas storage bag from the first condenser, while the steam continuously insulates the pipeline. A 4: A mobile tubular heater is used to pyrolyze the raw material in the second heating zone inside the reaction tube. The second shut-off valve is opened and the first shut-off valve is closed. The generated gas is condensed in the second condenser to obtain the bio-oil ratio. The gas is collected by the second gas storage bag to obtain the biomass gas ratio. The difference between the raw material before and after the reaction is used to obtain the biochar ratio. A5: Move the tubular furnace to a non-raw material location and turn off the heating. Cool the raw material in the reaction tube to room temperature. The reaction is then complete.

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