Device for separating biochar and heat carrier in biomass thermal conversion process

Abstract

The present invention belongs to the field of resource carbon neutrality, and specifically discloses a device for separating biochar and heat carrier in the process of biomass thermal conversion, aiming to solve the problem of how to effectively separate heat carrier and biochar. The fluidized bed separation system of the device is mainly composed of a separation outer tube, a lifting inner tube and a baffle outlet gas component. The baffle of the baffle outlet gas component can block the particle mixture sprayed out of the gas outlet to guide most of the particle mixture to the annular bubbling chamber, and then the particle size and density difference between biochar and heat carrier can be used, combined with the fluidizing wind sent in by the outer tube inlet pipe, to control the gas-solid flow structure in the annular bubbling chamber, so that particles with particle size and density differences show different descending distances in the process, and the lighter biochar particles are suspended on the bed surface and transported out from the upper overflow pipe, and the heavier heat carrier settles to the lower side of the biochar particles and is transported out from the lower overflow pipe, thereby achieving the purpose of efficient separation of particles in the dense phase area.

Description

Technical Field

[0001] The present invention belongs to the field of resource carbon neutrality, and specifically relates to a device for separating biochar and heat carrier in the process of biomass thermal conversion. Background Art

[0002] Under the goal of carbon neutrality, the future development path is to transform from fossil energy to renewable energy. As an important substitute for fossil resources, biomass is the world's most abundant renewable resource, the only renewable resource that can replace fossil resources on a large scale, and the only zero-carbon fuel among internationally recognized renewable energy sources.

[0003] Biomass refers to various organisms formed through photosynthesis, including plants, animals and microorganisms. Biomass can be converted into traditional solid, liquid and gaseous fuels through thermochemical methods such as gasification and pyrolysis, which significantly increases the efficiency of biomass energy utilization and effectively replaces fossil fuels.

[0004] In order to improve the quality of pyrolysis / gasification products, many processes use catalysts or heat carriers to improve the efficiency of reaction and heat transfer. Most catalysts and heat carriers need to be recycled in the reaction system, so the separation of pyrolysis / gasification products and catalysts / heat carriers needs to be considered. If the biochar particles produced by pyrolysis / gasification inside the reactor cannot be removed quickly, the carbon particles in the reactor will reduce the yield of bio-oil. If the carbon particles accumulate in the reactor, it will cause fluidization problems and cause the reaction to stop.

[0005] To avoid the above problems, one can choose to burn biochar, and the heat generated by the combustion of biochar is used to heat the heat carrier and then recycled back to the reactor. However, under this reactor configuration, solid ash may return to the reactor, which may lead to unnecessary ash accumulation in the system, thereby reducing the bio-oil yield. In addition, biochar used for combustion heating is also a widely used material that can be used to make adsorbents, catalyst carriers, energy storage materials, fertilizers, etc. If the larger carbon particles remaining in the reactor can be selectively separated, not only can the yield and quality of bio-crude oil be improved, but also higher value biochar can be recovered.

[0006] In order to separate carbon particles, the journal Agricultural Mechanization Research (Xu Shizhen, Yi Weiming, Li Zhihe, Zhang Deli. Study on the separation characteristics of heat carrier and biomass semi-coke particles [J]. Agricultural Mechanization Research, 2011, 33 (12): 191-194 + 199.) disclosed a process for separating biomass semi-coke particles and heat carrier. The process proposed to use inertia to separate biomass semi-coke particles and heat carrier, and further screen them using a screen. However, in the process, the heat carrier has a significant carrying effect on the biomass semi-coke particles, which reduces the separation efficiency, and the screen is prone to cause coking and blockage of the bed.

[0007] In order to reduce the collision between particles and improve the separation efficiency, the Chinese invention patent application with the publication number CN106269508A discloses an annular fluidized bed separator for a particle mixture, in which the upper end of the central riser extends into the annular fluidized bed to a certain height, so that the annular fluidized bed is divided into a lower annular area and an upper cylindrical area; an air inlet and an air distribution plate are provided at the bottom of the central riser and the annular fluidized bed, respectively; a feed port is provided at the bottom of the central riser, and a heavy particle outlet is provided at the bottom of the annular area of ​​the annular fluidized bed to connect with the heavy particle collection tank, and the airflow outlet at the top of the annular fluidized bed is connected to the light particle collection tank via a cyclone separator. The particle mixture is rapidly fluidized in the central riser and dispersed once; then it rises with the airflow into the annular fluidized bed for secondary dispersion.

[0008] Although the annular fluidized bed separator for the above-mentioned particle mixture can continuously and quickly separate the light and heavy particle mixture with high efficiency under normal temperature or high temperature conditions, and solves the problem of insufficient dispersion of particle groups and violent collisions between particles in traditional air classifiers, resulting in low separation efficiency, but because it uses a gravity field and generates drag between gas and solid through a cyclone separator for separation in the dilute phase region, there is still the problem that the larger the particle size of the light particles, the easier it is to be carried by the heavy particles, resulting in difficulty in separating heat carriers with high specific gravity and small particle size and biochar particles with low specific gravity and large particle size, and the separation efficiency of light particles is low. Summary of the invention

[0009] The present invention provides a device for separating biochar from a heat carrier in a biomass thermal conversion process, aiming to solve the problem of how to effectively separate the heat carrier from the biochar.

[0010] The technical solution adopted by the present invention to solve the technical problem is: a device for separating biochar and heat carrier in the process of biomass thermal conversion, comprising an entrained bed separation system, a feeding system and a pneumatic conveying system;

[0011] The entrained bed separation system comprises a vertically arranged separation outer tube and a lifting inner tube whose upper end extends into the separation outer tube, wherein the lifting inner tube divides the inner cavity of the separation outer tube into an upper exhaust cavity and a lower annular bubbling cavity;

[0012] The upper and lower ends of the separation outer tube are both closed structures, and the lower end is provided with an outer tube air inlet pipe connected to the annular bubbling cavity, and a lower overflow pipe is obliquely provided on the side wall of the separation outer tube, and the upper end feed port of the lower overflow pipe is connected to the annular bubbling cavity;

[0013] The upper end of the lifting inner tube is provided with a gas outlet, and the lower end thereof is provided with a lifting air inlet; a feed pipe is provided on the pipe section of the lifting inner tube that does not extend into the separation outer tube;

[0014] The feeding system comprises a feeding bin, the outlet of which is connected to the feeding port of the feeding pipe;

[0015] The air outlet of the pneumatic conveying system is respectively connected to the air inlet of the outer tube air inlet pipe and the lifting air inlet;

[0016] An upper overflow pipe is obliquely arranged on the side wall of the separation outer pipe, the upper overflow pipe is located on the upper side of the lower overflow pipe, and the upper end feed port of the upper overflow pipe is connected to the annular bubbling chamber;

[0017] The fluidized bed separation system further comprises a flow-blocking gas outlet component; the flow-blocking gas outlet component comprises a baffle plate arranged in the exhaust cavity and directly above the gas outlet, and a gas outlet pipe extending into the exhaust cavity at the lower end;

[0018] An exhaust gas inlet is arranged on the pipe section of the air outlet pipe extending into the exhaust cavity. The exhaust gas inlet is located on the upper side of the baffle. An exhaust gas outlet is arranged at the upper end of the air outlet pipe.

[0019] Furthermore, an annular gas distributor is provided in the annular bubbling chamber, and the annular gas distributor is located at the lower side of the upper end feed port of the lower overflow pipe;

[0020] The upper edge of the annular gas distributor is provided with at least two fluidizing air outlet holes evenly distributed along its circumference. The annular gas distributor is also provided with a fluidizing air inlet, which is connected to the outlet of the outer tube inlet pipe.

[0021] Furthermore, the device also includes a collection system and a dust removal system;

[0022] The feeding system also includes a feeding control valve arranged on the feeding pipe;

[0023] The collection system includes a biochar collection tank and a heat carrier collection tank;

[0024] The feed inlet of the biochar collection tank is connected to the lower end outlet of the upper overflow pipe;

[0025] The feed inlet of the heat carrier collection tank is connected to the lower end outlet of the lower overflow pipe;

[0026] The exhaust gas outlet is connected to the air inlet of the dust removal system through a transfer tube.

[0027] Furthermore, a guide groove is provided on the bottom surface of the baffle;

[0028] The lower end of the air outlet pipe is connected to the top surface of the baffle;

[0029] There are at least two exhaust gas inlets, which are evenly distributed along the circumference of the exhaust pipe;

[0030] The dust removal system comprises a dust removal tank, in which dust removal liquid is contained, and a dust removal air inlet pipe and a dust removal air outlet pipe are arranged on the dust removal tank;

[0031] The air inlet of the dust removal air inlet pipe is the air inlet of the dust removal system, and the air outlet of the dust removal air inlet pipe is immersed in the dust removal liquid;

[0032] The dust removal air outlet pipe is communicated with the inner cavity of the dust removal tank and is located above the liquid level of the dust removal liquid.

[0033] Further, the pneumatic conveying system includes a gas source, a gas purifier and a gas pressure reducer;

[0034] The gas outlet of the gas source is connected to the gas inlet of the gas purifier;

[0035] The gas outlet of the gas purifier is connected to the gas inlet of the gas pressure reducer;

[0036] The gas outlet of the gas pressure reducer is the gas outlet of the pneumatic conveying system, and the gas outlet of the gas pressure reducer is connected to the lifting wind inlet through a first gas pipeline with a first gas flow meter. The gas outlet of the gas pressure reducer is also connected to the gas inlet of the outer tube inlet pipe through a second gas pipeline with a second gas flow meter.

[0037] Furthermore, the height-to-diameter ratio of the separation outer tube is 8-25:1, and the ratio of the inner diameter of the lifting inner tube to the inner diameter of the separation outer tube is 1:1.5-6.

[0038] Furthermore, the inner diameter of the separation outer tube is 8 to 16 cm and the length is 1.5 to 2 m;

[0039] The inner diameter of the lifting inner pipe is 3 to 5 cm and the length is 1.5 to 2.5 m;

[0040] The distance between the gas outlet and the bottom surface of the baffle is 30 to 50 cm.

[0041] Furthermore, the distance between the upper end feed port of the upper overflow pipe and the bottom surface of the separation outer tube is 1 / 3 to 2 / 3 of the length of the separation outer tube, and the angle between the central axis of the upper overflow pipe and the central axis of the separation outer tube is 30° to 60°;

[0042] The distance between the upper feed port of the lower overflow pipe and the bottom surface of the separation outer pipe is 1 / 25 to 1 / 10 of the length of the separation outer pipe, and the angle between the central axis of the lower overflow pipe and the central axis of the separation outer pipe is 30° to 60°.

[0043] The present invention also provides a method for effectively separating heat carriers with high specific gravity and small particle size from biochar particles with low specific gravity and large particle size. The method uses the above-mentioned device for separating biochar and heat carriers in the process of biomass thermal conversion as a separation device to separate biochar and heat carriers in the process of biomass thermal conversion.

[0044] The biomass includes but is not limited to one of wine dregs, straw and sawdust, and the heat carrier includes but is not limited to one of aluminum oxide, quartz sand and ceramic balls;

[0045] The ratio of the biochar to the heat carrier is 1:30-60.

[0046] Further, the method includes an intake air flow rate control step;

[0047] Inlet flow rate control steps: During the operation of the separation equipment, the inlet flow rate of the lift air inlet is controlled to U1, U1 = 2.5 ~ 3m / s; the inlet flow rate of the air inlet of the outer tube inlet pipe is controlled to U2, U2 = 1 ~ 1.40U mf <U1;

[0048] U mf It indicates the minimum fluidization velocity of the bed layer at which the particle mixture can be fluidized in the annular bubbling chamber to form a bubbling fluidized bed;

[0049] The particle mixture includes gas, heat carrier and biochar.

[0050] The beneficial effects of the present invention are:

[0051] 1) The device does not need to use a cyclone separator to perform gas-solid separation again during the separation process. Compared with the prior art, the device has a simpler structure, lower manufacturing and use costs, and is easy to apply industrially.

[0052] 2) The fluidized bed separation system of the device is mainly composed of a separation outer tube, a lifting inner tube and a baffle outlet gas component. The heat carrier and the biochar are separated by the fluidized bed formed by the separation outer tube and the lifting inner tube extending into the separation outer tube at the upper end. During the separation process, the lifting air is sent in from the lifting air inlet to make the mixed material fluidized quickly at a high gas velocity and form a particle mixture. The baffle of the baffle outlet gas component can block the particle mixture sprayed out of the gas outlet to guide most of the particle mixture to the annular bubbling chamber. Since an upper overflow pipe for conveying biochar and a lower overflow pipe for conveying heat carrier are simultaneously arranged on the side wall of the separation outer tube, the biochar is used to separate the heat carrier from the heat carrier. The gas-solid flow structure in the annular bubbling chamber is controlled by combining the particle size and density difference of the heat carrier and the fluidizing air sent in by the outer tube air inlet pipe, so that the bubbles and cavities in the bed of the bubbling fluidized bed are constantly moving and exchanging. Particles with different particle sizes and densities show different descending distances in the process. The lighter biochar particles are suspended on the bed surface and transported out from the upper overflow pipe, and the heavier heat carrier settles to the lower side of the biochar particles and is transported out from the lower overflow pipe, thereby achieving the purpose of efficient separation of particles in the dense phase area. Ultimately, the biochar with small specific gravity and large particle size can be effectively separated from the heat carrier with large specific gravity and small particle size in the process of biomass thermal conversion, thereby improving the separation efficiency of light particles.

[0053] 3) The device can continuously and quickly separate the mixture of biochar and heat carrier with high efficiency and achieve a high processing capacity.

[0054] 4) By controlling the air inlet velocity of the lifting air inlet to 2.5-3m / s, the air inlet velocity of the outer air inlet pipe is controlled to U2, U2 = 1-1.40U mf <U1, which can achieve the purpose of effectively regulating the gas-solid two-phase flow structure, making the bubble effect in the bubbling fluidized bed most obvious, greatly improving the separation efficiency of biochar particles with small specific gravity and large particle size. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a schematic diagram of the implementation structure of the present invention;

[0056] Figure 2 It is a schematic diagram of the implementation structure of the entrained bed separation system of the present invention;

[0057] Figure 3 It is a schematic diagram of the implementation structure of the annular gas distributor in the present invention;

[0058] Figure 4 It is a schematic diagram of the implementation structure of the outflow blocking gas component in the present invention;

[0059] Figure 5 It is a working principle diagram of the entrained bed separation system in the present invention;

[0060] Figure 6 is a graph showing the influence of the intake air velocity at the intake port of the outer tube intake pipe on the axial distribution of the carbon particle mass fraction in Example 1;

[0061] Figure 7 is a graph showing the influence of the intake air velocity at the intake port of the outer intake pipe on the axial distribution of the logarithm of the carbon particle mass fraction in Example 1;

[0062] Figure 8 is a graph showing the influence of the intake air velocity at the air inlet of the outer air intake pipe on the axial distribution of the carbon particle mass fraction in Example 2;

[0063] Fig. 9 is a graph showing the influence of the intake air velocity at the intake port of the outer intake pipe on the axial distribution of the logarithm of the carbon particle mass fraction in Example 2;

[0064] Marked in the figure are: fluidized bed separation system 1, feed pipe 11, separation outer pipe 12, exhaust chamber 121, annular bubbling chamber 122, lifting inner pipe 13, gas outlet 131, lifting air inlet 132, annular gas distributor 14, fluidizing air outlet hole 141, fluidizing air inlet 142, outer pipe inlet pipe 15, upper overflow pipe 16, lower overflow pipe 17, flow blocking gas outlet component 18, baffle 181, guide groove 1811, gas outlet pipe 182, waste gas inlet 1821, waste gas outlet 1822, transfer pipe 183, feed bin 2, feed control valve 3, biochar collection tank 4, heat carrier collection tank 5, dust removal tank 6, dust removal inlet pipe 61, dust removal outlet pipe 62, gas source 71, gas purifier 72, gas pressure reducer 73, first gas flow meter 74, second gas flow meter 75. DETAILED DESCRIPTION

[0065] The present invention will be further described below in conjunction with the accompanying drawings.

[0066] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention; the term "multiple" refers to two or more; the expression "mainly composed of..." is interpreted as also containing structural components not mentioned in the sentence; "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships, for example: A and / or B, which can indicate: A exists alone, A and B exist at the same time, and B exists alone; the symbol " / " is a separator, which means "or" when it separates two optional or convertible items, and means "and" when it separates two items forming a pair. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0067] Combination Figure 1 and Figure 2 As shown, the device for separating biochar and heat carrier in the process of biomass thermal conversion comprises an entrained bed separation system 1, a feeding system and a pneumatic conveying system;

[0068] The entrained flow separation system 1 is the main component of the device, which is used to form an entrained flow bed to separate biochar and heat carrier in the process of biomass thermal conversion; the entrained flow separation system 1 includes a vertically arranged separation outer tube 12 and a lifting inner tube 13 whose upper end extends into the separation outer tube 12, and the lifting inner tube 13 divides the inner cavity of the separation outer tube 12 into an upper exhaust cavity 121 and a lower annular bubbling cavity 122; the annular bubbling cavity 122 can be a variety of annular structures, preferably a circular ring structure that can improve the separation effect;

[0069] The upper and lower ends of the separation outer tube 12 are both closed structures, and the lower end is provided with an outer tube air inlet pipe 15 connected to the annular bubbling cavity 122, and a lower overflow pipe 17 is obliquely provided on the side wall of the separation outer tube 12, and the upper end feed port of the lower overflow pipe 17 is connected to the annular bubbling cavity 122; the lower overflow pipe 17 is mainly used to transport the separated heat carrier out;

[0070] The lifting inner tube 13 is mainly used as a conveying bed of the fluidized bed separation system 1; the upper end of the lifting inner tube 13 is provided with a gas outlet 131, and the lower end thereof is provided with a lifting air inlet 132; the pipe section of the lifting inner tube 13 that does not extend into the separation outer tube 12 is provided with a feed pipe 11;

[0071] The feeding system is mainly used to feed the mixed material to be separated into the entrained bed separation system 1, wherein the mixed material includes biochar and heat carrier; the feeding system includes a feeding bin 2, and the discharge port of the feeding bin 2 is connected to the feeding port of the feeding pipe 11;

[0072] The pneumatic conveying system is mainly used to convey lifting air and fluidizing air to the fluidized bed separation system 1, so as to fluidize the mixed material, form a particle mixture and convey it into the annular bubbling chamber 122 at a high speed, and then fluidize the particle mixture at a low gas speed to form a bubbling fluidized bed; the air outlet of the pneumatic conveying system is respectively connected to the air inlet of the outer tube air inlet pipe 15 and the lifting air inlet 132;

[0073] An upper overflow pipe 16 is obliquely arranged on the side wall of the separation outer tube 12. The upper overflow pipe 16 is located on the upper side of the lower overflow pipe 17, and the upper end feed port of the upper overflow pipe 16 is connected to the annular bubbling chamber 122; the upper overflow pipe 16 is mainly used to transport the separated biochar;

[0074] The entrained bed separation system 1 further includes a flow blocking gas outlet component 18; the flow blocking gas outlet component 18 includes a baffle 181 disposed in the exhaust cavity 121 and directly above the gas outlet 131, and a gas outlet pipe 182 with a lower end extending into the exhaust cavity 121;

[0075] The baffle 181 is mainly used to return most of the particle mixture sprayed from the gas outlet 131 to the annular bubbling chamber 122, so as to save the cyclone separator and facilitate the continuous movement and exchange of bubbles and cavities in the particle mixture in the annular bubbling chamber 122, so that particles with different particle sizes and densities present different falling distances, thereby effectively separating the biochar; a baffle structure for improving its baffle effect is usually provided on the bottom surface of the baffle 181, such as an inverted "V" shaped structure, an arc-shaped baffle groove, etc.;

[0076] The gas outlet pipe 182 is mainly used to discharge excess waste gas in the separation outer pipe 12 to control the pressure in the fluidized bed separation system 1 and ensure continuous and efficient separation of biochar and heat carrier; a waste gas inlet 1821 is provided on the pipe section of the gas outlet pipe 182 extending into the exhaust chamber 121, and the waste gas inlet 1821 is located on the upper side of the baffle 181, and a waste gas outlet 1822 is provided at the upper end of the gas outlet pipe 182.

[0077] The fluidized bed separation system 1 of the device is mainly composed of a separation outer tube 12, a lifting inner tube 13 and a baffle outlet component 18. The fluidized bed formed by the separation outer tube 12 and the lifting inner tube 13 extending into the separation outer tube 12 at the upper end is used to separate the heat carrier and the biochar. During the separation process, lifting air is introduced from the lifting air inlet 132 to fluidize the mixed material quickly at a high gas velocity, and the baffle 181 of the baffle outlet component 18 can block the particle mixture sprayed out of the gas outlet 131, so that most of the particle mixture is guided and transported to the annular bubbling chamber 122. Since an upper overflow pipe 16 for transporting out the biochar and a lower overflow pipe 17 for transporting out the heat carrier are simultaneously provided on the side wall of the separation outer tube 12, it can The difference in particle size and density between biochar and heat carrier is utilized, and combined with the fluidizing air introduced by the outer tube air inlet pipe 15, to control the gas-solid flow structure in the annular bubbling chamber 122, so that the particle mixture is fluidized at a low gas velocity to form a bubbling fluidized bed. In the bed, bubbles and cavities are constantly moving and exchanging, and particles with particle size and density differences show different falling distances in this process. The lighter biochar particles are suspended on the bed surface and transported out from the upper overflow pipe 16, and the heavier heat carrier settles to the lower side of the biochar particles and is transported out from the lower overflow pipe 17, thereby achieving the purpose of efficient separation of particles in the dense phase region, and ultimately the biochar with small specific gravity and large particle size and the heat carrier with large specific gravity and small particle size generated in the biomass thermal conversion process can be effectively separated.

[0078] Considering that the height-to-diameter ratio of the separation outer tube 12 and the ratio of the inner diameter of the lifting inner tube 13 to the inner diameter of the separation outer tube 12 are too large or too small, they may lead to uneven distribution of gas flow in the bed, and then lead to two more serious abnormal fluidizations, surging and channeling, which cause serious wear of the vessel wall and reduce the separation efficiency; therefore, it is preferred to control the height-to-diameter ratio of the separation outer tube 12 to 8-25:1, and control the ratio of the inner diameter of the lifting inner tube 13 to the inner diameter of the separation outer tube 12 to 1:1.5-6. The height-to-diameter ratio of the separation outer tube 12 refers to the ratio of the length of the separation outer tube 12 to the inner diameter of the separation outer tube 12.

[0079] More preferably, the inner diameter of the separation outer tube 12 is 8 to 16 cm and the length is 1.5 to 2 m;

[0080] The inner diameter of the lifting inner pipe 13 is 3 to 5 cm and the length is 1.5 to 2.5 m;

[0081] After the separation outer tube 12 and the lifting inner tube 13 of the above-mentioned size are matched, the particle mixture can be more evenly dispersed in the annular bubbling cavity 122 to ensure the separation effect and avoid the adverse effects on particle separation caused by problems such as the feeding position and size; the thickness of the lifting inner tube 13 is usually 1 / 10 to 1 / 5 of its inner diameter;

[0082] The distance between the gas outlet 131 and the bottom surface of the baffle 181 is 30 to 50 cm; in this way, the continuity of separation of the entire device can be guaranteed and the separation efficiency can be guaranteed; if the distance is too large, it is easy for more particles to be carried by the gas or brought out from the exhaust gas inlet 1821 through inertia, reducing the separation efficiency; if the distance is too small, it is easy to cause the particle mixture to be sprayed out poorly, increasing the energy consumption of the device and reducing the separation speed.

[0083] More preferably, the distance between the upper end feed port of the upper overflow pipe 16 and the bottom surface of the separation outer tube 12 is 1 / 3 to 2 / 3 of the length of the separation outer tube 12, and the angle between the central axis of the upper overflow pipe 16 and the central axis of the separation outer tube 12 is 30° to 60°;

[0084] The distance between the upper feed port of the lower overflow pipe 17 and the bottom surface of the separation outer tube 12 is 1 / 25 to 1 / 10 of the length of the separation outer tube 12, and the angle between the central axis of the lower overflow pipe 17 and the central axis of the separation outer tube 12 is 30° to 60°.

[0085] Controlling the upper overflow pipe 16 and the lower overflow pipe 17 at the above-mentioned angular position can ensure the smoothness of the discharge and avoid bridging blockage; since the biochar mass fraction at the top of the bed is the highest and the heat carrier mass fraction at the bottom of the bed is the highest, installing the upper overflow pipe 16 and the lower overflow pipe 17 at the above-mentioned height positions respectively can ensure that the upper overflow pipe 16 and the lower overflow pipe 17 correspond to the top of the bed and the bottom of the bed respectively, so as to further improve the separation efficiency of the particles.

[0086] Specific, combined Figure 2 and Figure 3 As shown, an annular gas distributor 14 is provided in the annular bubbling chamber 122, and the annular gas distributor 14 is located at the lower side of the upper end feed port of the lower overflow pipe 17;

[0087] The upper edge of the annular gas distributor 14 is provided with at least two fluidizing air outlet holes 141 evenly distributed along its circumference. The annular gas distributor 14 is also provided with a fluidizing air inlet 142 , and the fluidizing air inlet 142 is connected to the outlet of the outer tube inlet pipe 15 .

[0088] The annular bubbling chamber 122 is mainly used to allow the fluidizing air delivered by the outer tube air inlet pipe 15 to blow upward uniformly in the annular bubbling chamber 122 to form a uniform and stable bubbling fluidized bed, which is beneficial to improving the separation effect of biochar and heat carrier.

[0089] In order to improve the effect of flow blocking and exhaust gas discharge, combined with Figure 2 and Figure 4As shown, a guide groove 1811 is provided on the bottom surface of the baffle 181; the guide groove 1811 is mainly used to guide the flow downward, and it can be a variety of structures, such as: an inverted "V"-shaped structure, a "⌒"-shaped structure, an arc-shaped retaining groove, etc.;

[0090] The lower end of the air outlet pipe 182 is connected to the top surface of the baffle 181;

[0091] There are at least two exhaust gas inlets 1821, which are evenly distributed along the circumference of the exhaust pipe 182; this facilitates the exhaust gas to be discharged evenly, helps to ensure the flow stability of the fluidized bed, and improves the separation effect of the bubbling fluidized bed.

[0092] Specifically, Figure 1 As shown, the device also includes a collection system and a dust removal system;

[0093] The feeding system further comprises a feeding control valve 3 arranged on the feeding pipe 11, and the feeding control valve 3 is mainly used to control the feeding amount and feeding speed to ensure the separation effect; the feeding control valve 3 can be of various types, preferably a ball valve;

[0094] The collection system is mainly used to collect the separated biochar and heat carrier; the collection system includes a biochar collection tank 4 and a heat carrier collection tank 5;

[0095] The feed port of the biochar collection tank 4 is connected to the lower end discharge port of the upper overflow pipe 16;

[0096] The feed inlet of the heat carrier collection tank 5 is connected to the lower end outlet of the lower overflow pipe 17;

[0097] The dust removal system is mainly used to remove a small portion of fine powder particles carried by gas or through inertia. The dust removal system can be of various types, such as bag dust collector, spray tower, etc.

[0098] The exhaust gas outlet 1822 is connected to the air inlet of the dust removal system through a transfer tube 183; the transfer tube 183 is mainly used to connect the exhaust gas outlet 1822 to the air inlet of the dust removal system, and it can be a variety of structures, preferably a bent pipe connected to the upper end of the outlet pipe 182 through a flange.

[0099] Preferably, Figure 1 As shown, the dust removal system includes a dust removal tank 6, in which dust removal liquid is contained, and a dust removal air inlet pipe 61 and a dust removal air outlet pipe 62 are provided on the dust removal tank 6;

[0100] The air inlet of the dust removal air inlet pipe 61 is the air inlet of the dust removal system, and the air outlet of the dust removal air inlet pipe 61 is immersed in the dust removal liquid;

[0101] The dust removal outlet pipe 62 is connected to the inner cavity of the dust removal tank 6 and is located above the liquid surface of the dust removal liquid. The dust removal liquid can be of various types and can be specifically prepared according to the composition of the exhaust gas and the substances to be removed.

[0102] The dust removal system has a simple structure, is easy to use, has a good dust removal effect, and has low manufacturing and use costs.

[0103] Preferably, Figure 1 As shown, the pneumatic conveying system includes a gas source 71, a gas purifier 72 and a gas pressure reducer 73;

[0104] The gas source 71 is mainly used to provide a gas medium for generating lifting wind and fluidizing wind, which can be various, such as: a gas tank, a compressor, a fan, etc.; the gas outlet of the gas source 71 is connected to the gas inlet of the gas purifier 72;

[0105] The gas purifier 72 is mainly used to remove impurities in the gas medium or substances that are not conducive to the separation of the mixed materials; the gas outlet of the gas purifier 72 is connected to the gas inlet of the gas pressure reducer 73;

[0106] The gas pressure reducer 73 is mainly used to regulate the pressure and flow rate of the gas medium for easy use; the gas outlet of the gas pressure reducer 73 is the gas outlet of the pneumatic conveying system, and the gas outlet of the gas pressure reducer 73 is connected to the lifting wind inlet 132 through a first gas pipeline with a first gas flowmeter 74, and the gas outlet of the gas pressure reducer 73 is also connected to the gas inlet of the outer tube air inlet pipe 15 through a second gas pipeline with a second gas flowmeter 75.

[0107] Specifically, the gas source 71 is an air compressor, the gas purifier 72 is an air purifier, and the gas pressure reducer 73 is a pressure reducing valve.

[0108] Combination Figure 1 , Figure 2 and Figure 5As shown, the working principle of the fluidized bed separation system 1 for separating biochar and heat carrier is as follows: the mixed material is fed into the lifting inner pipe 13 through the feed pipe 11, and the lifting air entering from the lifting air inlet 132 makes the mixed material fluidized quickly to form a conveying bed of the particle mixture; the particle mixture rises with the air flow and is ejected from the gas outlet 131, a small part of the fine powder particles are carried by the gas or continue to rise by inertia, and then discharged into the dust removal system through the gas outlet pipe 182 for capture and treatment, and most of the particle mixture is blocked by the baffle 181 and enters under the action of gravity. into the annular bubbling chamber 122; the particle mixture in the annular bubbling chamber 122 is fluidized to form a bubbling fluidized bed due to the fluidizing wind entering from the outer tube air inlet pipe 15, in which bubbles and cavities continuously move and exchange, so that particles with different particle sizes and densities show different descending distances in the process, thereby separating the biochar from the heat carrier, and the lighter biochar particles are suspended on the bed surface, discharged from the upper overflow pipe 16 and collected by the biochar collecting tank 4, and the heavier heat carrier particles are discharged from the lower overflow port 17 and collected by the heat carrier collecting tank 5.

[0109] The present invention also provides a method for separating biochar from a heat carrier in a biomass thermal conversion process, wherein the method uses the above-mentioned device for separating biochar from a heat carrier in a biomass thermal conversion process as a separation device to separate the biochar from the heat carrier in the biomass thermal conversion process;

[0110] The biomass may be of various types, including but not limited to one of wine dregs, straw and sawdust, including but not limited to other substances with similar properties in addition to the listed example substances, for example: the biomass may also be coconut shells, rice shells, etc.; the heat carrier may also be of various types, including but not limited to one of aluminum oxide, quartz sand and ceramic balls;

[0111] The ratio of the biochar to the heat carrier is 1:30-60.

[0112] Preferably, the method comprises an intake air flow rate control step;

[0113] Inlet flow rate control step: During the operation of the separation device, the inlet flow rate of the lift air inlet 132 is controlled to U1, U1 = 2.5-3 m / s, at which the particle group can be stably and effectively transported to the annular bubbling chamber 122, and the fine powder particles can be prevented from being carried out by the air-solid drag force to the greatest extent;

[0114] The air intake velocity of the air intake port of the outer air intake pipe 15 is controlled to U2, U2 = 1 ~ 1.40U mf <U1, at this gas velocity, the bubble effect in the bubbling fluidized bed is most obvious, and the separation effect is better;

[0115] Umf represents the minimum fluidization velocity of the bed layer at which the particle mixture can be fluidized in the annular bubbling chamber 122 to form a bubbling fluidized bed;

[0116] The particle mixture includes gas, heat carrier and biochar.

[0117] Example 1

[0118] The device for separating biochar from heat carrier in the process of biomass thermal conversion provided by the present invention is used as a separation device to separate the biochar from the heat carrier in the binary particle mixture A;

[0119] In the above device, the inner diameter of the separation outer tube 12 is 85 mm and the tube length is 1.7 m, the inner diameter of the lifting inner tube 13 is 40 mm and the tube length is 2 m, and the distance between the gas outlet 131 and the bottom surface of the baffle 181 is 30 cm;

[0120] The mass flow rate of the binary particle mixture A is controlled by the feed control valve 3;

[0121] The binary particle mixture A is a mixture of biochar I and heat carrier in a ratio of 1:30. The separation principle of this embodiment is: the binary particle mixture A is added to the feed bin 2 and transported into the annular bubbling chamber 122. mf The fluidization is carried out at a gas velocity of , at which time the gas and solid in the bed are in intense turbulent fluidization, and the particles are fully mixed and then show different falling distances.

[0122] The specific separation process is as follows: the mixed material A is fed into the lifting inner tube 13 from the feed pipe 11, and the inlet flow rate of the lifting air inlet 132 is controlled to U1=2.56m / s. The lifting air entering from the lifting air inlet 132 causes the mixed material to be rapidly fluidized to form a conveying bed of the particle mixture; the particle mixture is ejected from the gas outlet 131 as the air flow rises, and a small part of the fine powder particles are carried by the gas or continue to rise by inertia, and then discharged into the dust removal system through the air outlet pipe 182 for capture and treatment, and most of the particle mixture is blocked by the baffle 181 and enters the annular bubbling chamber 122 under the action of gravity; the inlet flow rate of the air inlet of the outer tube inlet pipe 15 is controlled to U2, U2=1~1.40U mf , U mf=0.15m / s; the particle mixture in the annular bubbling chamber 122 is fluidized to form a bubbling fluidized bed due to the fluidizing wind entering from the outer tube air inlet pipe 15. In the bubbling fluidized bed, bubbles and cavities are constantly moving and exchanging, so that particles with different particle sizes and densities show different descending distances in the process, thereby separating the biochar from the heat carrier. The lighter biochar particles are suspended on the bed surface, discharged from the upper overflow pipe 16 and collected by the biochar collection tank 4, and the heavier heat carrier particles are discharged from the lower overflow port 17 and collected by the heat carrier collection tank 5.

[0123] In this embodiment, the properties of the particles involved and the properties of the binary particle mixture are shown in Table 1 and Table 2 below, respectively.

[0124] In this embodiment, five sampling points are evenly arranged axially on one side of the separation outer tube 12, and sampling is performed after the bed is separated to explore the axial distribution of the bed particles. Figure 6 and Figure 7 As shown, X represents the mass fraction of carbon particles, and X0 represents the mass fraction of carbon particles in the initial bed layer; it can be seen that for the device of the size of this embodiment, when the feeding rate of the binary particle mixture A is 20 kg / h, as the gas velocity at the inlet of the outer tube inlet pipe 15 increases, the separation degree of the entire bed layer gradually increases; the gas velocity is selected as U2 = 1.13 ~ 1.40U mf The separation efficiency of biochar and heat carrier can reach more than 95%. The separation efficiency of biochar separated by the device can reach up to 96%. The separation efficiency of biochar is defined as: the proportion of the mass of carbon particles obtained from the biochar collection tank 4 to the total mass of carbon particles entering the device. The separation efficiency of heat carrier can reach up to 98%. The separation efficiency of heat carrier is defined as: the proportion of the mass of heat carrier particles obtained from the heat carrier collection tank 5 to the total mass of heat carrier particles entering the device.

[0125] Example 2

[0126] The device for separating biochar from heat carrier in the process of biomass thermal conversion provided by the present invention is used as a separation device to separate the biochar from the heat carrier in the binary particle mixture B;

[0127] In the above device, the inner diameter of the separation outer tube 12 is 15 cm and the tube length is 2 m, the inner diameter of the lifting inner tube 13 is 5 cm and the tube length is 2.5 m, and the distance between the gas outlet 131 and the bottom surface of the baffle 181 is 50 cm;

[0128] The mass flow rate of the binary particle mixture B is controlled by the feed control valve 3;

[0129] The binary particle mixture B is a mixture of biochar II and heat carrier in a ratio of 1:60. The separation principle of this embodiment is: the binary particle mixture B is added to the feed bin 2 and transported into the annular bubbling chamber 122. mf The fluidization is carried out at a gas velocity of , at which time the gas and solid in the bed are in intense turbulent fluidization, and the particles are fully mixed and then show different falling distances.

[0130] The specific separation process is as follows: the mixed material B is fed into the lifting inner tube 13 from the feed pipe 11, and the inlet flow rate of the lifting air inlet 132 is controlled to U1=3m / s. The lifting air entering from the lifting air inlet 132 makes the mixed material B fluidized quickly to form a conveying bed of the particle mixture; the particle mixture rises with the air flow and is ejected from the gas outlet 131, a small part of the fine powder particles are carried by the gas or continue to rise by inertia, and then discharged into the dust removal system through the gas outlet pipe 182 for capture and treatment, most of the particle mixture is blocked by the baffle 181 and enters the annular bubbling chamber 122 under the action of gravity; the inlet flow rate of the air inlet of the outer tube inlet pipe 15 is controlled to U2, U2=1~1.40U mf , U mf =0.15m / s; the particle mixture in the annular bubbling chamber 122 is fluidized to form a bubbling fluidized bed due to the fluidizing wind entering from the outer tube air inlet pipe 15. In the bubbling fluidized bed, bubbles and cavities are constantly moving and exchanging, so that particles with different particle sizes and densities show different descending distances in the process, thereby separating the biochar from the heat carrier. The lighter biochar particles are suspended on the bed surface, discharged from the upper overflow pipe 16 and collected by the biochar collection tank 4, and the heavier heat carrier particles are discharged from the lower overflow port 17 and collected by the heat carrier collection tank 5.

[0131] In this embodiment, the properties of the particles involved and the properties of the binary particle mixture are shown in Table 1 and Table 2 below, respectively.

[0132] In this embodiment, five sampling points are evenly arranged axially on one side of the separation outer tube 12, and sampling is performed after the bed is separated to explore the axial distribution of the bed particles. Figure 8 and Fig. 9 As shown, X represents the mass fraction of carbon particles, and X0 represents the mass fraction of carbon particles in the initial bed layer; it can be seen that for the device of the size of this embodiment, when the feeding rate of the binary particle mixture B is 20kg / h, as the gas velocity at the inlet of the outer tube inlet pipe 15 increases, the separation degree of the entire bed layer gradually increases; the gas velocity is selected as U2=1.00~1.40U mf The separation efficiency of biochar and heat carrier can reach more than 95%. The separation efficiency of biochar obtained by this device can reach up to 99%, and the separation efficiency of heat carrier can reach up to 98%.

[0133] Table 1: Properties of biochar and heat carrier

[0134] Particle name Raw material type <![CDATA[Particle density (kg / m 3 )]]> Screening particle size (um) Average particle size (um) Biochar I Lees 340 800～1000 900 Biochar Ⅱ Wood chips 450 600～800 700 Heat carrier Aluminum oxide 3900 280～320 300 ;

[0136] Table 2: Properties of binary particle mixtures

[0137] Biochar Heat carrier Quality Ratio Particle size ratio Density ratio A Lees Aluminum oxide 1:30 3 0.09 B Wood chips Aluminum oxide 1:60 2.33 0.12 .

Claims

1. A device for separating biochar from a heat carrier in a biomass thermal conversion process, comprising an entrained bed separation system (1), a feeding system and a pneumatic conveying system; The fluidized bed separation system (1) comprises a vertically arranged separation outer tube (12) and a lifting inner tube (13) whose upper end extends into the separation outer tube (12), wherein the lifting inner tube (13) divides the inner cavity of the separation outer tube (12) into an upper exhaust cavity (121) and a lower annular bubbling cavity (122); The upper and lower ends of the separation outer tube (12) are both closed structures, and the lower end is provided with an outer tube air inlet pipe (15) connected to the annular bubbling cavity (122); a lower overflow pipe (17) is obliquely provided on the side wall of the separation outer tube (12), and the upper end feed port of the lower overflow pipe (17) is connected to the annular bubbling cavity (122); The upper end of the lifting inner tube (13) is provided with a gas outlet (131), and the lower end thereof is provided with a lifting air inlet (132); a feed pipe (11) is provided on the pipe section of the lifting inner tube (13) that does not extend into the separation outer tube (12); The feeding system comprises a feeding bin (2), the discharge port of the feeding bin (2) being connected to the feeding port of the feeding pipe (11); The air outlet of the pneumatic conveying system is respectively connected to the air inlet of the outer tube air inlet pipe (15) and the lifting air inlet (132); Features: An upper overflow pipe (16) is obliquely arranged on the side wall of the separation outer pipe (12), the upper overflow pipe (16) is located on the upper side of the lower overflow pipe (17), and the upper end feed port of the upper overflow pipe (16) is connected to the annular bubbling chamber (122); The fluidized bed separation system (1) further comprises a flow-blocking gas outlet component (18); the flow-blocking gas outlet component (18) comprises a baffle (181) arranged in the exhaust chamber (121) and directly above the gas outlet (131), and a gas outlet pipe (182) whose lower end extends into the exhaust chamber (121); An exhaust gas inlet (1821) is provided on the pipe section of the exhaust pipe (182) extending into the exhaust chamber (121); the exhaust gas inlet (1821) is located on the upper side of the baffle (181); and an exhaust gas outlet (1822) is provided at the upper end of the exhaust pipe (182).

2. The device for separating biochar and heat carrier in the process of biomass thermal conversion according to claim 1, characterized in that: An annular gas distributor (14) is provided in the annular bubbling chamber (122), and the annular gas distributor (14) is located at the lower side of the upper feed port of the lower overflow pipe (17); The upper edge of the annular gas distributor (14) is provided with at least two fluidizing air outlet holes (141) evenly distributed along its circumference. The annular gas distributor (14) is also provided with a fluidizing air inlet (142), and the fluidizing air inlet (142) is connected to the outlet of the outer tube inlet pipe (15).

3. The device for separating biochar and heat carrier in the process of biomass thermal conversion according to claim 1, characterized in that: It also includes collection systems and dust removal systems; The feeding system further comprises a feeding control valve (3) arranged on the feeding pipe (11); The collection system comprises a biochar collection tank (4) and a heat carrier collection tank (5); The feed inlet of the biochar collection tank (4) is connected to the lower end discharge port of the upper overflow pipe (16); The feed inlet of the heat carrier collection tank (5) is connected to the lower end discharge port of the lower overflow pipe (17); The exhaust gas outlet (1822) is connected to the air inlet of the dust removal system via a transfer tube (183).

4. The device for separating biochar and heat carrier in the process of biomass thermal conversion according to claim 3, characterized in that: A flow guide groove (1811) is provided on the bottom surface of the baffle (181); The lower end of the air outlet pipe (182) is connected to the top surface of the baffle (181); There are at least two exhaust gas inlets (1821), which are evenly distributed along the circumference of the exhaust pipe (182); The dust removal system comprises a dust removal tank (6), the dust removal tank (6) is filled with dust removal liquid, and the dust removal tank (6) is provided with a dust removal air inlet pipe (61) and a dust removal air outlet pipe (62); The air inlet of the dust removal air inlet pipe (61) is the air inlet of the dust removal system, and the air outlet of the dust removal air inlet pipe (61) is immersed in the dust removal liquid; The dust removal outlet pipe (62) is in communication with the inner cavity of the dust removal tank (6) and is located above the liquid surface of the dust removal liquid.

5. The device for separating biochar and heat carrier in the process of biomass thermal conversion according to claim 1, characterized in that: The pneumatic conveying system comprises a gas source (71), a gas purifier (72) and a gas pressure reducer (73); The gas outlet of the gas source (71) is connected to the gas inlet of the gas purifier (72); The gas outlet of the gas purifier (72) is connected to the gas inlet of the gas pressure reducer (73); The gas outlet of the gas pressure reducer (73) is the gas outlet of the pneumatic conveying system, and the gas outlet of the gas pressure reducer (73) is connected to the lifting air inlet (132) via a first gas pipeline with a first gas flow meter (74), and the gas outlet of the gas pressure reducer (73) is also connected to the gas inlet of the outer tube inlet pipe (15) via a second gas pipeline with a second gas flow meter (75).

6. The device for separating biochar and heat carrier in the biomass thermal conversion process according to any one of claims 1 to 5, characterized in that: The height-to-diameter ratio of the separation outer tube (12) is 8 to 25:1, and the ratio of the inner diameter of the lifting inner tube (13) to the inner diameter of the separation outer tube (12) is 1:1.5 to 6.

7. The device for separating biochar and heat carrier in the process of biomass thermal conversion according to claim 6, characterized in that: The inner diameter of the separation outer tube (12) is 8 to 16 cm and the length is 1.5 to 2 m; The inner diameter of the lifting inner pipe (13) is 3 to 5 cm and the length is 1.5 to 2.5 m; The distance between the gas outlet (131) and the bottom surface of the baffle (181) is 30 to 50 cm.

8. The device for separating biochar and heat carrier in the process of biomass thermal conversion according to claim 6, characterized in that: The distance between the upper feed port of the upper overflow pipe (16) and the bottom surface of the separation outer pipe (12) is 1 / 3 to 2 / 3 of the length of the separation outer pipe (12), and the angle between the central axis of the upper overflow pipe (16) and the central axis of the separation outer pipe (12) is 30° to 60°; The distance between the upper feed port of the lower overflow pipe (17) and the bottom surface of the separation outer pipe (12) is 1 / 25 to 1 / 10 of the length of the separation outer pipe (12), and the angle between the central axis of the lower overflow pipe (17) and the central axis of the separation outer pipe (12) is 30° to 60°.

9. A method for separating biochar from heat carrier in a biomass thermal conversion process, characterized in that: The device for separating biochar from heat carrier in the process of thermal conversion of biomass as claimed in any one of claims 1 to 8 is used as a separation device to separate biochar from heat carrier in the process of thermal conversion of biomass; The biomass includes one of wine dregs, straw and wood chips, and the heat carrier includes one of aluminum oxide, quartz sand and ceramic balls; The ratio of the biochar to the heat carrier is 1:30-60.

10. The method for separating biochar and heat carrier in the biomass thermal conversion process according to claim 9, characterized in that: The method includes an intake air flow rate control step; Inlet flow rate control step: During the operation of the separation device, the inlet flow rate of the lift air inlet (132) is controlled to U1, U1=2.5~3 m / s; the inlet flow rate of the air inlet of the outer tube inlet pipe (15) is controlled to U2, U2=1~1.40U mf <U1; U mf represents the minimum fluidization velocity of the bed layer at which the particle mixture can be fluidized in the annular bubbling chamber (122) to form a bubbling fluidized bed; The particle mixture includes gas, heat carrier and biochar.

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