Catalytic pyrolysis device and catalytic pyrolysis method

Abstract

The invention relates to the technical field of chemical catalysis, and discloses a catalytic pyrolysis device and a catalytic pyrolysis method. The catalytic pyrolysis device comprises a feeding assembly, a reaction assembly, a condensation absorption assembly and a tail gas treatment assembly. The feeding assembly comprises a powder sample injector or a liquid phase injector, the powder sample injector comprises a stepping motor, a rotating shaft of the stepping motor is connected with a sample injection screw rod, and the stepping motor is electrically connected with a sample injection controller; a sample introduction controller is used for carrying out pulse trace control on sample introduction of the catalytic pyrolysis device, or a liquid phase injector is used for carrying out continuous trace control on the sample introduction of the catalytic pyrolysis device, so that a gas component generated after the pretreated biomass raw material is pyrolyzed is lower than the upper airspeed limit and passes through a catalyst, and the catalytic performance is ensured; components higher than the saturated vapor pressure of the catalytic pyrolysis product are collected through primary condensation, and components lower than the saturated vapor pressure of the catalytic pyrolysis product are collected through secondary absorption liquid. According to the catalytic pyrolysis device and the catalytic pyrolysis method provided by the invention, monocyclic aromatic hydrocarbon products with the pressure lower than the saturated vapor pressure in catalytic pyrolysis reaction products can be efficiently recovered under a low airspeed condition, and the reactant recovery efficiency is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of chemical catalysis, and particularly to a catalytic pyrolysis device and a catalytic pyrolysis and product recovery method. Background Art

[0002] As an effective way to convert biomass into high-value chemicals and fuels, biomass catalytic pyrolysis technology has received extensive attention in recent years. Through catalytic hydrodeoxygenation (HDO) technology, the oxygen-containing components in biomass can be effectively removed to produce liquid fuels with higher energy density. However, this process usually requires relatively low mass space velocity (the mass of reactants passing through the mass of unit catalyst per unit time). In a catalytic reaction, the size of the space velocity directly affects the contact time between the reactants and the catalyst, thereby affecting the reaction efficiency.

[0003] Most of the existing biomass catalytic pyrolysis devices and processes adopt high space velocity conditions and conventional condensation methods, which are not suitable for HDO catalysts. High space velocity often leads to incomplete HDO reaction, increased oxygen-containing products, and reduced yield of fully HDO products (such as benzene, toluene, ethylbenzene, etc.). However, the condensation of monocyclic aromatic hydrocarbon products is difficult at low space velocity because the partial pressure of these components in the pyrolysis gas is relatively low under low space velocity conditions, often lower than their saturated vapor pressure, and the conventional condensation method cannot effectively recover these valuable products, reducing the economic efficiency. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a catalytic pyrolysis device and a catalytic pyrolysis method, which can efficiently extract monocyclic aromatic hydrocarbon products with a partial pressure lower than their saturated vapor pressure in the products of catalytic pyrolysis reaction under low space velocity conditions.

[0005] To solve the above technical problems, an embodiment of the present application provides a catalytic pyrolysis device, which includes a feeding component, a reaction component, a condensation absorption component, and a tail gas treatment component. The feeding component includes a powder injector or a liquid-phase injector. The powder injector includes a stepping motor, the rotation shaft of the stepping motor is connected to a sampling screw, and the stepping motor is electrically connected to a sampling controller; the sampling of the catalytic pyrolysis device is controlled in a pulsed micro amount through the sampling controller, or the sampling of the catalytic pyrolysis device is controlled continuously in a micro amount through the liquid-phase injector, so that the gas components generated after the pyrolysis of the pretreated biomass raw material pass through the catalyst below the upper limit of the space velocity, ensuring the catalytic performance; the reaction component includes a reaction tube communicated with the feeding component, and the reaction tube includes a pyrolysis section close to the feeding component and a catalytic section far from the feeding component; the condensation absorption component includes a first condensation tube communicated with the reaction component, and a collection bottle communicated with the first condensation tube. A side wall of the collection bottle is communicated with an absorption bottle, a side wall of the absorption bottle is communicated with a second condensation tube, and an absorption liquid is provided in the absorption bottle to absorb the gas components with a vapor pressure lower than the saturation vapor pressure generated by the catalytic pyrolysis reaction; the tail gas treatment component is used to treat the tail gas overflowing from the absorption bottle; the biomass raw material undergoes a pyrolysis reaction in the pyrolysis section, the gas generated by the pyrolysis reaction undergoes a catalytic reaction in the catalytic section, the gas components with a vapor pressure higher than its saturation vapor pressure in the product gas after the catalytic reaction are recovered in the collection bottle, and the gas components with a vapor pressure lower than its saturation vapor pressure are collected in the absorption bottle.

[0006] In addition, an embodiment of the present application also provides a catalytic pyrolysis method using the above catalytic pyrolysis equipment, and the catalytic pyrolysis method includes the following steps:

[0007] S11: Pretreat the biomass raw material at a high temperature to remove free water and pyrolyze part of the cellulose;

[0008] S12: Install a spacer and a catalyst in the reaction tube;

[0009] S13: Load an appropriate amount of biomass raw material into the feeding component;

[0010] S14: Control the heating of the catalytic section to a set temperature by programmed heating to activate the catalyst;

[0011] S15: Introduce a reaction gas into the reaction tube, start the powder injector or the liquid-phase injector, and perform micro-sampling control;

[0012] S16: Control the heating of the pyrolysis section and the catalytic section to a set temperature by programmed heating to complete the catalytic pyrolysis reaction;

[0013] S17: Recover the gas components with a vapor pressure higher than its saturation vapor pressure in the product gas after the catalytic reaction in the collection bottle;

[0014] S18: Collect the gas components with a vapor pressure lower than its saturation vapor pressure in the product gas after the catalytic reaction in the absorption bottle.

[0015] The catalytic pyrolysis device and the catalytic pyrolysis method provided by the embodiments of the present application perform pulsed micro-control on the sample injection of the catalytic pyrolysis device through a sample injection controller, or perform continuous micro-control on the sample injection of the catalytic pyrolysis device through a liquid-phase syringe, so that the gas components generated after the pyrolysis of the pretreated biomass raw material pass through the catalyst at a space velocity lower than the upper limit, ensuring the catalytic performance. Then, the gas components with a product component higher than its saturated vapor pressure are collected through the first condenser tube, and finally, the non-condensable components lower than the saturated vapor pressure generated by the catalytic pyrolysis reaction are absorbed by the absorbent liquid in the absorption bottle. Therefore, it is possible to efficiently recover the monocyclic aromatic hydrocarbon products lower than their saturated vapor pressures in the catalytic pyrolysis reaction products under low space velocity conditions, improving the recovery efficiency of the reactants.

[0016] In some embodiments, the feeding assembly further includes a feeding pipe. One end of the feeding pipe is connected to a feed pipe, and the other end is connected to the reaction pipe. The feed pipe is connected to a hopper, and a feeding screw is arranged in the feed pipe. The hopper is filled with biomass raw materials.

[0017] In some embodiments, the reaction pipe is connected to a gas pipeline, and nitrogen or hydrogen can be provided according to the requirements of specific reactions. A branch pipe is connected between the hopper and the feeding pipe.

[0018] In some embodiments, a closed end is provided at one end of the catalytic section away from the feeding assembly. Isolation members are respectively provided at the middle position between the pyrolysis section and the catalytic section and at the closed end. A first heat-insulating sleeve is arranged around the pyrolysis section in a circle, and a second heat-insulating sleeve is arranged around the catalytic section in a circle. Electric heating wires are arranged on the inner walls of the first heat-insulating sleeve and the second heat-insulating sleeve.

[0019] In some embodiments, the side wall of the absorption bottle is connected to a second condenser tube. The tail gas treatment assembly includes a bubbler connected to the outlet of the second condenser tube.

[0020] In some embodiments, the condensed water of the first condenser tube and the second condenser tube is connected in series through a pipeline, and the isolation member is quartz wool.

[0021] In some embodiments, the absorption bottle includes an internal transfer pipe and an external containing bottle. One end of the transfer pipe is connected to the collection bottle, and the other end is connected to a sintered glass filter.

[0022] In some embodiments, the containing bottle includes a long cylindrical bottle at the lower end and a spherical bottle at the upper end. An absorbent liquid is placed in the long cylindrical bottle, and the spherical bottle is connected to the second condenser tube.

[0023] In some embodiments, the biomass raw material is coconut shell, the catalyst is molybdenum carbide, ethanol needs to be injected during the activation of the catalyst, the reaction temperature of the pyrolysis section is set at 550 °C, and the reaction temperature of the catalytic section is set at 350 °C.

[0024] In some embodiments, the injection rate of the powder injector is 35 mg / min, and the absorption bottle is placed in a constant temperature water bath. Description of the Drawings

[0025] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements. Unless otherwise stated, the drawings in the figures do not constitute a scale limitation.

[0026] Figure 1 is a schematic diagram of the variation of the saturated vapor pressure of some substances with temperature;

[0027] Figure 2 is a schematic diagram of the connection structure when the catalytic pyrolysis device provided by some embodiments of the present application uses a powder injector;

[0028] Figure 3 is a schematic diagram of the connection structure when the catalytic pyrolysis device provided by some embodiments of the present application uses a liquid-phase syringe;

[0029] Figure 4 is a cross-sectional view of the reaction tube structure in the catalytic pyrolysis device provided by some embodiments of the present application;

[0030] Figure 5 is a cross-sectional view of the absorption bottle structure in the catalytic pyrolysis device provided by some embodiments of the present application;

[0031] Figure 6 is a flowchart of the catalytic pyrolysis method provided by some embodiments of the present application.

[0032] Description of the Reference Numerals in the Drawings: 11 - feeding assembly; 111 - powder injector; 1111 - stepping motor; 1112 - injection screw; 112 - liquid-phase syringe; 113 - blanking pipe; 114 - feed pipe; 115 - hopper; 116 - gas pipeline; 117 - branch pipe; 12 - reaction assembly; 121 - reaction tube; 1211 - pyrolysis section; 1212 - catalytic section; 1213 - closing end; 122 - spacer; 123 - first heat-insulating sleeve; 124 - second heat-insulating sleeve; 125 - electric heating wire; 13 - condensation absorption assembly; 131 - first condenser; 132 - collection bottle; 133 - absorption bottle; 1331 - transfer pipe; 1332 - receiving bottle; 1333 - long-neck bottle; 1334 - spherical bottle; 1335 - sintered filter; 134 - second condenser; 14 - tail gas treatment assembly; 141 - bubbler. Detailed Embodiments

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will elaborate on the various embodiments of this application in conjunction with the accompanying drawings. Those of ordinary skill in the art can understand that in the various embodiments of this application, many technical details are presented to help readers better understand this application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in this application can still be implemented. The division of the following embodiments is for convenience of description and should not constitute any limitation to the specific implementation of this application. The various embodiments can be combined and cross-referenced with each other on the premise of not being contradictory.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description of the specification, claims, and the above drawings of this application are intended to cover non-exclusive inclusion.

[0035] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "a plurality of" is more than two, unless otherwise specifically defined.

[0036] In the description of the embodiments of this application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0037] As an effective way to convert biomass into high-value-added chemicals and fuels, biomass catalytic pyrolysis technology has received extensive attention in recent years. Through catalytic hydrodeoxygenation (HDO) technology, the oxygen-containing components in biomass can be effectively removed to produce liquid fuels with higher energy density. However, this process usually requires relatively low space velocity (the mass of reactants passing through the mass of the catalyst per unit time). In a catalytic reaction, the magnitude of the space velocity directly affects the contact time between the reactants and the catalyst, thereby affecting the reaction efficiency.

[0038] Most of the existing biomass catalytic pyrolysis devices and processes adopt high space velocity conditions and conventional condensation methods, which are not applicable to HDO catalysts. High space velocity often leads to incomplete HDO reactions, increased oxygen-containing products, and reduced yields of fully HDO products (such as benzene, toluene, ethylbenzene, etc.). However, the condensation of monocyclic aromatic hydrocarbon products is difficult at low space velocity because the partial pressure of these components in the pyrolysis gas under low space velocity conditions is relatively low, often lower than their saturation vapor pressure, and conventional condensation methods cannot effectively recover these valuable products, reducing economic efficiency.

[0039] Therefore, in order to efficiently recover monocyclic aromatic hydrocarbon products with a partial pressure lower than their saturation vapor pressure in the catalytic pyrolysis reaction products under low space velocity conditions. Some embodiments of the present application provide a catalytic pyrolysis device and a catalytic pyrolysis method. The sampling of the catalytic pyrolysis device is controlled in a pulsed microamount manner through a sampling controller, or the sampling of the catalytic pyrolysis device is continuously controlled in a microamount manner through a liquid-phase syringe, so that the gas components generated after the pyrolysis of the pretreated biomass raw material pass through the catalyst with a partial pressure lower than their saturation vapor pressure to ensure catalytic performance. The part with a product component higher than its saturation vapor pressure (polycyclic aromatic hydrocarbons) is collected through the first condenser tube, and finally the difficult-to-condense components with a partial pressure lower than the saturation vapor pressure generated by the catalytic pyrolysis reaction are absorbed by the absorbent liquid in the absorption bottle. Thus, monocyclic aromatic hydrocarbon products with a partial pressure lower than their saturation vapor pressure in the catalytic pyrolysis reaction products can be efficiently extracted under low space velocity conditions.

[0040] The following combines Figures 1 to 6 to illustrate the catalytic pyrolysis device and the catalytic pyrolysis method provided by some embodiments of the present application.

[0041] Such as Figure 2 、 Figure 3 and Figure 4As shown in the figure, the catalytic pyrolysis device provided by some embodiments of the present application includes a feeding component 11, a reaction component 12, a condensation absorption component 13, and a tail gas treatment component 14. The feeding component 11 includes a powder injector 111 or a liquid-phase injector 112. The powder injector 111 includes a stepping motor 1111. The rotating shaft of the stepping motor 1111 is connected to a sampling screw 1112. The stepping motor 1111 is electrically connected to a sampling controller. The sampling of the catalytic pyrolysis device is controlled in a pulsed micro mode through the sampling controller, or the sampling of the catalytic pyrolysis device is continuously controlled in a micro mode through the liquid-phase injector 112, so that the target gas components generated after the pyrolysis of the pretreated biomass raw materials pass through the catalyst at a low partial pressure, meeting the requirement of the low space velocity of the catalyst, ensuring the catalytic performance, and being lower than the upper limit of the catalyst space velocity. The reaction component 12 includes a reaction tube 121 communicated with the feeding component 11. The reaction tube 121 includes a pyrolysis section 1211 close to the feeding component 11 and a catalytic section 1212 far from the feeding component 11. The condensation absorption component 13 includes a first condensation tube 131 communicated with the reaction component 12, and a collection bottle 132 communicated with the first condensation tube 131. A side wall of the collection bottle 132 is communicated with an absorption bottle 133. A side wall of the absorption bottle 133 is communicated with a second condensation tube 134. An absorption liquid is provided in the absorption bottle 133 for absorbing the gas components with a vapor pressure lower than the saturation vapor pressure generated by the catalytic pyrolysis reaction. The tail gas treatment component 14 is used for treating the tail gas overflowing from the absorption bottle 133. The biomass raw materials undergo a pyrolysis reaction in the pyrolysis section 1211. The gas generated by the pyrolysis reaction undergoes a catalytic reaction in the catalytic section 1212. The gas components with a vapor pressure higher than their saturation vapor pressure in the product gas after the catalytic reaction are recovered in the collection bottle 132, and the gas components with a vapor pressure lower than their saturation vapor pressure are collected in the absorption bottle 133.

[0042] In some embodiments of the present application, the feeding component 11 further includes a blanking tube 113. One end of the blanking tube 113 is communicated with a feeding tube 114, and the other end is communicated with the reaction tube 121. The feeding tube 114 is communicated with a hopper 115. The sampling screw 1112 is arranged in the feeding tube 114. The hopper 115 is filled with biomass raw materials. After the biomass raw materials in the hopper 115 enter the feeding tube 114, they are squeezed into the blanking tube 113 driven by the sampling screw 1112 and then enter the reaction tube 121 to react.

[0043] In some embodiments of the present application, a closing end 1213 is arranged at one end of the catalytic section 1212 far from the feeding component 11. Partition members 122 are respectively arranged at the middle position between the pyrolysis section 1211 and the catalytic section 1212 and at the closing end 1213. A first heat preservation sleeve 123 is arranged around the pyrolysis section 1211 in a circle, and a second heat preservation sleeve 124 is arranged around the catalytic section 1212 in a circle. Electric heating wires 125 are arranged on the inner walls of the first heat preservation sleeve 123 and the second heat preservation sleeve 124.

[0044] In some embodiments of the present application, a second condenser 134 is connected to the side wall of the absorption flask 133, and the tail gas treatment assembly 14 includes a bubbler 141 connected to the outlet of the second condenser 134.

[0045] It should be noted that the feeding assembly 11, the reaction assembly 12, the condensation absorption assembly 13, and the tail gas treatment assembly are all connected by detachable connections, which is convenient for replacement and cleaning. The components and the internal parts are hermetically connected (when using quartz and glass components in the laboratory, standard ground glass joints can be used) to ensure the airtightness of the entire device. The pre-treated biomass raw material is loaded from the inlet of the hopper 115. Driven by the stepping motor 1111, the sampling screw 1112 rotates, and the raw material in the hopper 115 is extruded into the reaction tube 121 connected below. The sampling controller can set and control the sampling period and rotation speed of the stepping motor 1111, so as to adjust the amount of the sampled material and meet the catalytic pyrolysis conditions of different biomass raw materials. The pyrolysis reaction occurs in the pyrolysis section 1211, and the residue after the reaction is blocked in the pyrolysis section 1211 by the separator 122. The generated gas enters the catalytic section 1212 and undergoes a catalytic reaction under the action of a catalyst. The first heat-insulating sleeve 123, the second heat-insulating sleeve 124, and the internal electric heating wire 125, under the control of the temperature controller (up to 800 °C), provide suitable temperatures for the pyrolysis reaction and the catalytic reaction. The appearance of the closed end 1213 is the same as that of the overall reaction tube 121, and the internal flow channel is funnel-shaped, from thick to thin, and shrinks into a small hole, which is used in combination with the separator 122 to prevent the catalyst from leaking into the lower condensation absorption assembly 13. In the first condenser 131, the gas components of the reactant gas whose partial pressure is greater than its saturated vapor pressure are liquefied and concentrated in the collection flask 132. The absorption flask 133 absorbs polycyclic aromatic hydrocarbons and other gas components whose partial pressure is lower than its saturated vapor pressure, realizing the separation of different products and also improving the extraction efficiency of the reaction products. The tail gas after passing through the absorption flask 133 is absorbed in the bubbler 141 and then discharged into the fume hood or other tail gas collection devices.

[0046] In addition, by controlling the feeding amount through the sampling controller, the amount of catalytic pyrolysis products can be controlled. Since the outlet and the inlet of the entire device are at the same atmospheric pressure, the total pressure in the device is always approximately equal to the atmospheric pressure. The partial pressure of the gas can be controlled by controlling the amount of the gas product, meeting the requirement of being lower than the upper limit of the catalyst space velocity. At this time, some monocyclic aromatic hydrocarbon products have a partial pressure lower than their saturated vapor pressure, and conventional condensation is difficult. Figure 1It is a schematic diagram of the saturated vapor pressures of typical catalytic pyrolysis gas components at different temperatures. It can be seen from the figure that as the temperature decreases, the saturated vapor pressures of various substances gradually decrease, but the trends are inconsistent. By comparing the actual partial pressure (0.03 bar) with the saturated vapor pressure curve, it can be judged that at the given temperature of 300 K (room temperature), the saturated vapor pressures of the several substances shown in the figure: benzene and toluene are both above 0.03 bar and cannot be collected by conventional condensation; the vapor pressures of naphthalene and guaiacol are both below 0.03 bar and can be collected by the condensation method.

[0047] The catalytic pyrolysis device provided by some embodiments of the present application performs pulsed micro-control on the sample injection of the catalytic pyrolysis device through a sample injection controller, or performs continuous micro-control on the sample injection of the catalytic pyrolysis device through a liquid-phase syringe 112, so as to provide a small amount of suitable biomass raw material within a certain time period, making the monocyclic aromatic hydrocarbon gas product components generated after its catalytic pyrolysis lower than its saturated vapor pressure, meeting the requirements of the catalyst for a low space velocity. The part with a product component higher than its saturated vapor pressure (naphthalene, polycyclic aromatic hydrocarbons such as alkylnaphthalene) is collected through the first condenser 131, and finally the difficult-to-condense components lower than the saturated vapor pressure generated by the catalytic pyrolysis reaction are absorbed by the absorbent liquid in the absorption bottle 133. Thus, it is possible to efficiently recover the monocyclic aromatic hydrocarbon products lower than their saturated vapor pressures in the catalytic pyrolysis reaction products under low space velocity conditions, improving the recovery efficiency of the reactants.

[0048] In some embodiments of the present application, the reaction tube 121 is connected to a gas pipeline 116, a branch pipe 117 is connected between the hopper 115 and the feeding pipe 113, and the spacer 122 is quartz wool.

[0049] It should be noted that the upper opening of the reaction tube 121 can be connected to the gas pipeline 116, and a hydrogen or nitrogen gas pipeline can be provided through the gas pipeline 116 as the carrier gas for the pyrolysis reaction and to participate in the catalytic reaction. According to the different properties of the biomass raw materials, some raw materials only need to be pyrolyzed without catalysis, and in this case, only nitrogen is added as the carrier gas; while for other raw materials, both pyrolysis and catalysis are required, and in this case, hydrogen is provided as the carrier gas and reaction gas. The liquid-phase syringe 112 is connected to the feeding pipe 113 through a liquid-phase injection needle for injecting the liquid raw material into the reaction tube 121. The liquid-phase syringe 112 has a chamber for storing liquid, or is connected to a box that can store liquid, and the liquid sample is pumped into the reaction tube 121 through an injection pump. The liquid-phase syringe 112 can be connected to the feeding pipe 113, or the injection needle of the liquid-phase syringe 112 can be directly inserted into the upper port of the reaction tube 121. The branch pipe 117 is used to balance the pressures of the two parts of the feeding pipe 113 and the hopper 115.

[0050] In some embodiments of the present application, the condensed water of the first condenser 131 and the second condenser 134 is connected in series through a pipeline, and the spacer 122 is quartz wool.

[0051] It should be noted that the first condenser 131 is for condensing the part of the gas components in the reactants that is greater than the saturated vapor pressure, and the second condenser 134 is for condensing the absorbent that has volatilized into gas, improving the absorption yield of the product and making full use of the absorbent. The quartz wool has the properties of high temperature resistance, light weight and heat conduction, and is suitable as an isolator for the catalyst. The isolator 122 at the middle position of the reaction tube 121 is, on the one hand, to prevent the residue after the pyrolysis of biomass from entering the catalytic section 1212, and on the other hand, to isolate the catalyst at the lower end. The isolator 122 at the position of the closed end 1213 is to prevent the catalyst from flowing into the lower condenser.

[0052] In some embodiments of the present application, the absorption bottle 133 includes an internal conduit 1331 and an external receiving bottle 1332. One end of the conduit 1331 is connected to the collection bottle 132, and the other end is connected to a sand core 1335.

[0053] It should be noted that the conduction bottle conducts the gas after passing through the first condenser 131 into the receiving bottle 1332. The receiving bottle 1332 is filled with an absorbent such as anhydrous ethanol or dichloromethane. The sand core 1335 is a cylindrical porous object with a pore diameter of 40 - 80 microns. When the gas comes out from the sand core 1335, many small bubbles are generated in the absorbent, making the product fully contact with the absorbent and facilitating dissolution and absorption.

[0054] In some embodiments of the present application, the receiving bottle 1332 includes a lower long tube bottle 1333 and an upper spherical bottle 1334. The absorbent is placed in the long tube bottle 1333, and the spherical bottle 1334 is connected to the second condenser 134.

[0055] It should be noted that, as Figure 5 shown, the long tube bottle 1333 is shaped like a graduated cylinder and is filled with the absorbent to increase the residence time of the gas in the absorbent. The spherical bottle 1334 is to prevent the absorbent from overflowing under the impact of the bubbles and provides a larger storage space for the absorbent. The absorbent condensed by the second condenser 134 flows back into the long tube bottle 1333 from the spherical bottle 1334. The long tube bottle 1333 and the spherical bottle 1334 are an integrally formed whole, called the receiving bottle 1332.

[0056] Some embodiments of the present application also provide a catalytic pyrolysis method, using the catalytic pyrolysis device as described in any one of the above, as Figure 6 shown, including the following steps:

[0057] S11: Pretreat the biomass raw material at high temperature to remove free water and pyrolyze part of the cellulose;

[0058] It should be noted that the purpose of pretreatment is to eliminate the influence of water on the performance of the catalyst. During the catalytic pyrolysis of biomass, a large amount of water and acidic substances are generated in the hydrodeoxygenation reaction. Especially when the biomass contains a large amount of oxygen-containing compounds, these by-products will accumulate rapidly. Water and acid will poison the catalyst, leading to catalyst deactivation and directly affecting the efficiency and stability of the reaction. Removing the free water and partial pyrolysis products in the biomass at a temperature of 250 °C can reduce the generation of water and acid in the subsequent hydrodeoxygenation process, effectively reducing the poisoning effect on the catalyst.

[0059] Specifically, a two-stage heating method can be used to pretreat the biomass raw material. First, the biomass is calcined at 150 °C to remove the free water on the surface of the biomass, and then it is calcined at 250 °C to pyrolyze part of the cellulose and hemicellulose, that is, to release in advance the components that can generate water and acid. Thus, the generation of water and acid during the catalytic process is reduced, the poisoning effect on the catalyst is alleviated, and the service life and efficiency of the catalyst are improved.

[0060] S12: Install the spacer 122 and the catalyst in the reaction tube 121;

[0061] Specifically, first install the quartz wool of the spacer 122 at the bottom, i.e., the closed end 1213, of the reaction tube 121, and then install the catalyst. After the catalyst is installed close to the middle position of the reaction tube 121, stop installing the catalyst, and finally install quartz wool as the spacer 122.

[0062] S13: Load an appropriate amount of biomass raw material into the feeding assembly 11;

[0063] It should be noted that the solid powder raw material is loaded into the hopper 115, and the liquid biomass raw material, such as bio-oil, is loaded into the liquid injector 112. According to the different types of biomass, solid or liquid raw materials are reasonably selected.

[0064] S14: Control the heating of the catalytic section 1212 to the set temperature through programmed temperature rise to activate the catalyst;

[0065] It should be noted that when activating the catalyst, only the electric heating wire 125 (which can be a nickel-chromium resistance wire) of the catalytic section 1212 needs to be turned on, so that the catalytic section 1212 heats up and cools down according to the set program, and an appropriate amount of activator (such as ethanol is required for activating the molybdenum carbide catalyst) is injected.

[0066] S15: Introduce the reaction gas into the reaction tube 121, start the powder injector 111 or the liquid injector 112, and perform micro-injection control;

[0067] It should be noted that the powder injector 111 can achieve pulsed solid-phase micro-sampling control, while the liquid-phase syringe 112 adopts continuous micro-sampling control. These two different sampling modes can meet the sampling control requirements of different biomass raw materials. Whether it is solid phase or liquid phase, it is necessary to control the amount entering the reaction tube 121 to ensure that the low space velocity requirement of the catalyst is met.

[0068] S16: Through programmed temperature control, heat the pyrolysis section 1211 and the catalytic section 1212 to the set temperature to complete the catalytic pyrolysis reaction;

[0069] Generally speaking, the temperature of the pyrolysis section 1211 is higher than that of the catalytic section 1212. Programmed temperature control can not only control the temperature, but also control the heating rate and heating time, and complete the pyrolysis and catalytic reactions within a certain temperature and time.

[0070] S17: Recover the gas in the product gas after the catalytic reaction in the collection bottle 132 that is higher than its saturated vapor pressure;

[0071] S18: Collect the gas in the product gas after the catalytic reaction in the absorption bottle 133 that is lower than its saturated vapor pressure.

[0072] It should be noted that the part of the product components higher than their saturated vapor pressure is collected through the first condenser 131 (primary condensation), and the difficult-to-condense components lower than the saturated vapor pressure generated in the catalytic pyrolysis reaction are absorbed by the absorption liquid in the absorption bottle 133 (secondary absorption).

[0073] For the catalytic hydrodeoxygenation reaction, if the partial pressure of the pyrolysis gas components is too high, it will exceed the processing capacity of the catalyst, resulting in a poor catalytic effect. Therefore, pulsed micro-sampling is required to control the pyrolysis gas in a low partial pressure state to meet the requirement of being lower than the maximum space velocity of the catalyst and ensure the catalytic effect. After the pyrolysis gas undergoes catalytic hydrodeoxygenation, low-pressure target products are generated, and the saturated vapor pressures of these target products are often relatively high, making it difficult to collect them by condensation (when the partial pressure of the component is lower than the saturated vapor pressure, even if the dew point is reached, condensation cannot occur).

[0074] Therefore, the catalytic pyrolysis device and catalytic pyrolysis method proposed in this application present a baking pretreatment - sampling control - condensation absorption secondary recovery system. By high-temperature baking, the influence of water on the catalyst performance is eliminated. Through pulsed (or continuous) micro-sampling, it is ensured that the reaction proceeds within the processing range of the catalyst (the self-performance of the hydrodeoxygenation catalyst limits the space velocity to be small and the partial pressure of the components to be low); through condensation, components such as polycyclic aromatic hydrocarbons can be recovered, and through the absorption liquid, low-pressure monocyclic aromatic hydrocarbon components that cannot be effectively condensed by conventional condensation can be collected.

[0075] Example 1

[0076] The raw material is coconut shell oil obtained by pyrolysis at 550 °C (degrees Celsius). Molybdenum carbide with a particle size of 20 - 40 mesh is used as the catalyst, which is placed in the catalytic section 1212 of the reaction tube 121. The catalyst needs to be activated before the formal experiment. The activation temperature is 680 °C, and the catalytic temperature is 350 °C. After the catalyst activation is completed, coconut shell oil is injected at a rate of 25 μL / min using a liquid-phase syringe 112, and its vaporization temperature is 350 °C.

[0077] Among them, the primary condensation obtains a primary condensation product accounting for 33 wt% (weight percentage) of the raw material, and the secondary ethanol absorption device obtains a recovery product accounting for 17.5 wt% of the raw material mass. The proportion of substances in each stage of the recovery product is shown in Table 1 (the yield is the ratio of each stage of the product). This device can achieve the effect of almost completely converting oxygen-containing substances such as phenols in the raw material coconut shell oil.

[0078] Experimental data show that through the two-stage recovery system, the complete enrichment and recovery of non-oxygen-containing substances such as aromatic hydrocarbons have been achieved, and the product collection effect of the secondary device is very significant.

[0079] Table 1 Analysis of the collected products at each stage of the catalytic pyrolysis of coconut shell oil

[0080]

[0081]

[0082] Example 2

[0083] The raw material is coconut shell powder with a particle size of 40 - 60 mesh that has been pre-calcined at 250 °C. In the experiment, molybdenum carbide catalyst with a particle size of 20 - 40 mesh is used. The catalyst is placed at the lower part of the quartz reaction tube 121 and needs to be pre-activated at 680 °C. The catalytic reaction temperature is set at 350 °C. The coconut shell powder is placed in the powder injector 111, and the injector is driven by a stepper motor 1111 to feed at a constant speed. The pyrolysis section 1211 reacts under the condition of isothermal pyrolysis at 550 °C.

[0084] The product adopts a two-stage recovery system: the primary condensation device obtains a condensed oil accounting for 13.3 wt% of the raw material, and the secondary ethanol absorption device obtains a recovery product accounting for 28.5 wt% of the raw material mass. The proportion of substances in each stage of the recovery product is shown in Table 2 (the yield is the ratio of each stage of the product).

[0085] Compared with the primary condensation product, it is found that the secondary recovery device can completely collect alkylbenzene aromatic hydrocarbon products. Through the two-stage recovery device, the complete enrichment and recovery of non-oxygen-containing substances such as aromatic hydrocarbons have been achieved.

[0086] Table 2 Analysis of the collected products at each stage of the coconut shell catalytic pyrolysis

[0087]

[0088] In some embodiments of the present application, dry coconut shells with a mesh size of 40 - 60 are used as raw materials, and molybdenum carbide is used as the catalyst. 10 g of coconut shells are loaded into the hopper 115. Ethanol needs to be injected during the activation of the catalyst. The reaction temperature of the pyrolysis section 1211 is set at 550 °C, and the reaction temperature of the catalytic section 1212 is set at 350 °C.

[0089] In some embodiments of the present application, the injection rate of the powder injector 111 is 35 mg / min (milligrams per minute), and the absorption bottle 133 is placed in a constant temperature water bath.

[0090] It should be noted that the absorption of gas requires a certain temperature. The higher the temperature, the greater the solubility. The constant temperature water bath ensures that the temperature can be controlled during the secondary absorption, enabling the gas components generated in the catalytic pyrolysis reaction that are below their saturated vapor pressures to be more fully absorbed by the absorption liquid in the absorption bottle 133. However, a certain temperature causes serious volatilization of the absorption liquid, which needs to be condensed and collected through a secondary condenser. The control system of the stepper motor 1111 sets the speed at 100 rpm (revolutions per minute), and precise rotation is achieved through a drive signal of 160 pulses per revolution (i.e., one full rotation is completed for every 160 pulses received). The motor operates in a pulse mode and pauses for 30 s (seconds) after each full rotation, forming a periodic action of "rotation - delay". Under these parameters, the overall feeding rate of the system is approximately 35 mg / min.

[0091] In addition, it should be emphasized that the catalytic pyrolysis device provided in the embodiments of the present application can also be used only as a pyrolysis device to meet the needs of some biomass raw material reactions that do not require catalytic reactions. When catalytic pyrolysis is carried out, hydrogen is introduced into the gas pipeline 116. When there is only pyrolysis without catalysis, nitrogen is introduced into the gas pipeline 116 in the device.

[0092] In some embodiments of the present application, HZSM - 5 is used as the catalyst, and dry coconut shells with a mesh size of 40 - 60 are used as raw materials. 10 g of coconut shells are loaded into the hopper 115. The pyrolysis temperature is 550 °C, and the catalytic temperature is 500 °C.

[0093] In some embodiments of the present application, HZSM - 5 is used as the catalyst, and dry Enteromorpha prolifera with a mesh size of 40 - 60 is used as raw materials. 10 g of Enteromorpha prolifera are loaded into the hopper 115. The pyrolysis temperature is 550 °C, and the catalytic temperature is 500 °C.

[0094] Those of ordinary skill in the art can understand that the above - described embodiments are specific examples for implementing the present application, and in actual applications, various changes can be made in form and details without departing from the spirit and scope of the present application.

Claims

1. Catalytic pyrolysis device, characterized in that: include: A feeding assembly, comprising a powder injector or a liquid phase injector, wherein the powder injector comprises a stepper motor, a rotating shaft of the stepper motor is connected to an injection screw, and the stepper motor is electrically connected to an injection controller; The sample injection of the catalytic pyrolysis device is controlled by pulse micro-control through the sample injection controller, or the sample injection of the catalytic pyrolysis device is controlled by continuous micro-control through the liquid phase injector, so that the gas components generated by the pyrolysis of the pretreated biomass raw material pass through the catalyst at a speed lower than the upper limit, thereby ensuring the catalytic performance; A reaction assembly, comprising a reaction tube connected to the feed assembly, wherein the reaction tube comprises a pyrolysis section close to the feed assembly and a catalytic section far from the feed assembly; A condensation absorption component, comprising a first condensation tube connected to the reaction component, and a collection bottle connected to the first condensation tube, wherein the collection bottle is connected to an absorption bottle, and the absorption bottle contains an absorption liquid for absorbing gas components below the saturated vapor pressure generated by the catalytic pyrolysis reaction; An exhaust gas treatment component, used for treating the exhaust gas overflowing from the absorption bottle; The biomass raw material undergoes a pyrolysis reaction in the pyrolysis section, and the gas generated by the pyrolysis reaction undergoes a catalytic reaction in the catalytic section. The gas components in the product gas after the catalytic reaction that are higher than their saturated vapor pressure are recovered in the collecting bottle, and the gas components that are lower than their saturated vapor pressure are collected in the absorption bottle.

2. The catalytic pyrolysis device according to claim 1, characterized in that: The feeding assembly also includes a feed pipe, one end of which is connected to a feed pipe, and the other end is connected to the reaction tube. The feed pipe is connected to a hopper, the injection screw is arranged in the feed pipe, and the hopper is filled with the biomass raw material.

3. The catalytic pyrolysis device according to claim 2, characterized in that: The reaction tube is connected with a gas pipeline, and a branch pipe is connected between the hopper and the feed pipe.

4. The catalytic pyrolysis device according to claim 1, characterized in that: The catalytic section is provided with a closing end at one end away from the feeding assembly, and isolation pieces are respectively provided at the middle position of the pyrolysis section and the catalytic section and at the closing end. A first insulation sleeve is provided around the pyrolysis section, and a second insulation sleeve is provided around the catalytic section. Electric heating wires are provided on the inner walls of the first insulation sleeve and the second insulation sleeve.

5. The catalytic pyrolysis device according to claim 1, characterized in that: The side wall of the absorption bottle is connected to a second condenser, and the tail gas treatment component includes a bubbler connected to the outlet of the second condenser.

6. The catalytic pyrolysis device according to claim 5, characterized in that: The absorption bottle comprises an internal conduction tube and an external containing bottle. One end of the conduction tube is connected to the collecting bottle, and the other end is connected to a sand core.

7. The catalytic pyrolysis device according to claim 6, characterized in that: The containing bottle comprises a long cylindrical bottle at the lower end and a spherical bottle at the upper end, the absorption liquid is placed in the long cylindrical bottle, and the spherical bottle is connected to the second condenser.

8. Catalytic pyrolysis method, characterized in that: Using the catalytic pyrolysis device as described in any one of claims 1 to 7 comprises the following steps: The biomass raw materials are pretreated at high temperature to remove free water and pyrolyze part of the cellulose; placing the separator and the catalyst into the reaction tube; Loading an appropriate amount of biomass raw materials into the feeding assembly; The catalytic section is heated to a set temperature by controlling the temperature program so as to activate the catalyst; Introducing reaction gas into the reaction tube, starting the powder injector or the liquid phase injector, and performing micro-injection control; The pyrolysis section and the catalytic section are heated to a set temperature through programmed temperature control to complete the catalytic pyrolysis reaction; Recovering in the collecting bottle the gas having a pressure higher than the saturated vapor pressure of the product gas after the catalytic reaction; The gas below the saturated vapor pressure in the product gas after the catalytic reaction is collected in the absorption bottle.

9. The catalytic pyrolysis method according to claim 8, characterized in that: The biomass raw material is coconut shell, the catalyst is molybdenum carbide, ethanol needs to be injected when the catalyst is activated, the reaction temperature of the pyrolysis stage is set to 550°C, and the reaction temperature of the catalytic stage is set to 350°C.

10. The catalytic pyrolysis method according to claim 9, characterized in that: The powder injector has an injection rate of 35 mg / min, and the absorption bottle is placed in a constant temperature water bath.

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