阅读说明：本技术 一种生物质自热热解及生物油原位脱氧的方法与装置 (Method and device for biomass self-heating pyrolysis and bio-oil in-situ deoxidation ) 是由 李斌 刘东京 赵立军 于 2020-06-11 设计创作，主要内容包括：本发明公开了一种生物质自热热解及生物油原位脱氧的方法与装置,生物质在二氧化碳气氛下热解并引入氧化钙基吸附剂；所述氧化钙基吸附剂与二氧化碳反应生成碳酸钙释放出大量热量为热解过程供热；所述氧化钙与热解挥发分中的类二氧化碳组分反应生成碳酸钙实现生物油原位脱氧；所述碳酸钙与生物质焦经旋风分离送入煅烧炉在空气气氛下煅烧分解生成氧化钙后送入热解炉循环利用；生物质热解温度为500-700℃；碳酸钙煅烧分解温度为800-950℃。本发明将生物质热解过程与氧化钙碳酸化反应有机结合,利用氧化钙碳酸化反应为生物质热解过程供热以实现自热热解,且氧化钙还可将生物油中的氧以二氧化碳的形式原位脱除,从而提升生物油品质。(The invention discloses a method and a device for biomass self-heating pyrolysis and bio-oil in-situ deoxidation, wherein biomass is pyrolyzed in a carbon dioxide atmosphere and a calcium oxide-based adsorbent is introduced; the calcium oxide-based adsorbent reacts with carbon dioxide to generate calcium carbonate, and a large amount of heat is released to supply heat for the pyrolysis process; the calcium oxide reacts with the carbon dioxide-like component in the pyrolysis volatile component to generate calcium carbonate so as to realize in-situ deoxidation of the bio-oil; the calcium carbonate and the biomass coke are separated by cyclone, sent into a calcining furnace, calcined and decomposed in air atmosphere to generate calcium oxide, and then sent into a pyrolysis furnace for recycling; the biomass pyrolysis temperature is 500-700 ℃; the calcination decomposition temperature of the calcium carbonate is 800-950 ℃. According to the invention, the biomass pyrolysis process and the calcium oxide carbonation reaction are organically combined, the calcium oxide carbonation reaction is utilized to supply heat to the biomass pyrolysis process so as to realize self-heating pyrolysis, and the calcium oxide can also remove oxygen in the bio-oil in situ in the form of carbon dioxide, so that the quality of the bio-oil is improved.)

1. The device for biomass self-heating pyrolysis and bio-oil in-situ deoxidation is characterized by comprising a pyrolysis furnace (3), wherein a solid inlet end of the pyrolysis furnace (3) is connected with a storage bin, and a gas outlet end of the pyrolysis furnace (3) is connected with a cyclone separator (4); the solid outlet end of the cyclone separator (4) is connected with the solid inlet end of the calcining furnace (5), the gas outlet end of the cyclone separator (4) and the flue gas outlet end of the calcining furnace (5) are respectively connected with a heat exchanger, and CO is arranged in the heat exchanger₂A channel and an air channel; the CO is₂The outlet ends of the channel and the air channel are respectively connected with the air inlet end of the pyrolysis furnace (3) and the air inlet end of the calcining furnace (5); the biomass is pyrolyzed by supplying heat to the biomass through the carbonation reaction of calcium oxide in the pyrolyzing furnace (3), and the carbon dioxide-like substances generated by the pyrolysis of the biomass are absorbed in situ by the calcium oxide to realize the deoxidation of the bio-oil.

2. The device for the autothermal pyrolysis of biomass and the in-situ deoxygenation of bio-oil according to claim 1, wherein the pyrolysis furnace (3) is a fluidized bed pyrolysis furnace, and the solid inlet ends of the pyrolysis furnace (3) are respectively connected to the biomass silo (1) and the calcium oxide silo (2).

3. The device for the autothermal pyrolysis of biomass and the in-situ deoxygenation of bio-oil according to claim 1, wherein the heat exchanger comprises a first heat exchanger (6) and a second heat exchanger (7), the inlet end of the pyrolysis gas flow of the first heat exchanger (6) is communicated with the gas outlet end of the cyclone separator 4, and the flue gas of the second heat exchanger (7) isThe inlet end is communicated with the smoke outlet end of the calcining furnace (5); respectively utilizing pyrolysis gas and flue gas to react with CO₂The air stream and air are preheated.

4. The apparatus for autothermal pyrolysis of biomass and in-situ deoxygenation of bio-oil of claim 3, wherein the calciner (5) is a Loop-seal type furnace, a fixed bed or a fluidized bed type furnace.

5. The apparatus for autothermal pyrolysis of biomass and in-situ deoxygenation of bio-oil of claim 3 or 4, wherein the first heat exchanger (6) and the second heat exchanger (7) are shell and tube heat exchangers.

6. A method for biomass self-heating pyrolysis and bio-oil in-situ deoxidation is characterized in that biomass is pyrolyzed in a carbon dioxide atmosphere and a calcium oxide-based adsorbent is introduced; the calcium oxide-based adsorbent reacts with carbon dioxide to generate calcium carbonate, and a large amount of heat is released to supply heat for the pyrolysis process; the calcium oxide-based adsorbent reacts with the carbon dioxide-like component in the pyrolysis volatile component to generate calcium carbonate so as to realize in-situ deoxygenation of the bio-oil; the calcium carbonate and the biomass coke are separated by cyclone, sent into a calcining furnace, calcined and decomposed in air atmosphere to generate calcium oxide, and then sent into a pyrolysis furnace for recycling; the biomass pyrolysis temperature is 500-700 ℃; the calcination decomposition temperature of the calcium carbonate is 800-950 ℃.

7. The method for autothermal pyrolysis of biomass and in-situ deoxygenation of bio-oil of claim 6, wherein the carbon dioxide atmosphere is a pure carbon dioxide atmosphere or a carbon dioxide rich atmosphere; the carbon dioxide reacted with the calcium oxide-based adsorbent is carbon dioxide in the atmosphere and carbon dioxide generated during pyrolysis of the biomass.

8. The method for autothermal pyrolysis of biomass and in-situ deoxygenation of bio-oil of claim 6, wherein the ratio of the addition amount of the carbon dioxide and the calcium oxide-based sorbent to the biomass is adjusted according to pyrolysis conditions to meet the requirement of thermal self-sustaining in the pyrolysis process.

9. The method for autothermal pyrolysis of biomass and in-situ deoxygenation of bio-oil of claim 6, wherein the calcium oxide-based sorbent is calcium oxide, quicklime, calcined limestone or calcined dolomite.

10. The method for autothermal pyrolysis of biomass and in-situ deoxygenation of bio-oil of claim 6, wherein the pyrolysis coke is calcined with the generated calcium carbonate, and heat is provided for the calcium carbonate calcination regeneration process by its combustion exotherm.

Technical Field

The invention belongs to the technical field of biomass energy, and particularly relates to a method and a device for biomass self-heating pyrolysis and in-situ deoxygenation of bio-oil.

Background

The biomass pyrolysis process is an endothermic reaction process, usually an external heat source is required to continuously supply heat to maintain the biomass to be pyrolyzed at a certain stable temperature, and particularly, the biomass fast pyrolysis liquefaction process using bio-oil as a target product requires a fast temperature rise rate of biomass particles. On the one hand, the heating rate of the biomass can be increased by reducing the particle size of the biomass, and on the other hand, ensuring rapid supply and efficient transfer of heat are also essential factors.

However, in the conventional indirect heating type pyrolysis furnace, the external heat needs to be transferred through the wall of the pyrolysis reactor facing the inside of the reactor, and how to transfer the heat transferred from the external heat source to the wall of the reactor to the inside or the center of the reactor is further effectively transferred, especially after the technology is enlarged, the volume of the reactor is greatly increased, which directly affects the temperature distribution inside the reactor and the composition and quality of the pyrolysis product. At present, the rapid and efficient supply of heat in the pyrolysis process has become an important bottleneck limiting the scale-up of the pyrolysis technology.

In addition, the main product of the rapid biomass pyrolysis, namely the bio-oil, is a high-oxygen-content organic mixture, has the defects of low quality grade, strong acidity, high viscosity, low heat value, poor thermal stability and the like, greatly limits the further popularization and utilization of the bio-oil, and becomes an important direction for the high-value utilization of the bio-oil by carrying out deoxidation and upgrading on the bio-oil.

Disclosure of Invention

The invention provides a method and a device for biomass self-heating pyrolysis and bio-oil in-situ deoxidation according to the problems in the prior art.

The technical scheme adopted by the invention is as follows:

a device for biomass self-heating pyrolysis and bio-oil in-situ deoxidation comprises a pyrolysis furnace, wherein a solid inlet end of the pyrolysis furnace is connected with a storage bin, and a gas outlet end of the pyrolysis furnace is connected with a cyclone separator; the solid outlet end of the cyclone separator is connected with the solid inlet end of the calcining furnace, the gas outlet end of the cyclone separator and the flue gas outlet end of the calcining furnace are respectively connected with a heat exchanger, and CO is arranged in the heat exchanger₂A channel and an air channel; the CO is₂The outlet ends of the channel and the air channel are respectively connected with the air inlet end of the pyrolysis furnace and the calcining furnaceAn inlet end of the furnace; the self-heating pyrolysis of the biomass is realized by supplying heat for the biomass pyrolysis through the carbonation reaction of calcium oxide in the pyrolysis furnace, and the carbon dioxide-like substances generated by the biomass pyrolysis are absorbed in situ by the calcium oxide to realize the deoxidation of the bio-oil

Further, the pyrolysis furnace adopts a fluidized bed pyrolysis furnace, and the solid inlet end of the pyrolysis furnace is respectively connected with a biomass bin and a calcium oxide bin;

further, the heat exchanger comprises a first heat exchanger and a second heat exchanger, wherein the pyrolysis airflow inlet end of the first heat exchanger is communicated with the gas outlet end of the cyclone separator, and the flue gas inlet end of the second heat exchanger is communicated with the flue gas outlet end of the calcining furnace; respectively utilizing pyrolysis gas and flue gas to react with CO₂Preheating the airflow and the air;

further, the calcining furnace is a Loop-seal type combustion furnace, a fixed bed or fluidized bed type combustion furnace;

further, the first heat exchanger and the second heat exchanger are shell-and-tube heat exchangers.

A method for biomass self-heating pyrolysis and bio-oil in-situ deoxidation is disclosed, wherein biomass is pyrolyzed in carbon dioxide atmosphere and calcium oxide-based adsorbent is introduced; the calcium oxide-based adsorbent reacts with carbon dioxide to generate calcium carbonate, and a large amount of heat is released to supply heat for the pyrolysis process; the calcium oxide-based adsorbent reacts with the carbon dioxide-like component in the pyrolysis volatile component to generate calcium carbonate so as to realize in-situ deoxygenation of the bio-oil; the calcium carbonate and the biomass coke are separated by cyclone, sent into a calcining furnace, calcined and decomposed in air atmosphere to generate calcium oxide, and then sent into a pyrolysis furnace for recycling; the biomass pyrolysis temperature is 500-700 ℃; the calcination decomposition temperature of the calcium carbonate is 800-950 ℃.

Further, the carbon dioxide atmosphere is pure carbon dioxide atmosphere or carbon dioxide-rich atmosphere; the carbon dioxide reacted with the calcium oxide-based adsorbent is carbon dioxide in the atmosphere and carbon dioxide generated during pyrolysis of the biomass.

Further, the ratio of the addition amount of the carbon dioxide and the calcium oxide-based adsorbent to the biomass can be adjusted according to pyrolysis working conditions to meet the requirement of self-sustaining heat in the pyrolysis process.

Further, the calcium oxide-based adsorbent is calcium oxide, quicklime, calcined limestone or calcined dolomite.

Further, the pyrolytic coke is calcined together with the generated calcium carbonate, and heat is provided for the calcium carbonate calcination regeneration process through the combustion heat release of the pyrolytic coke.

The invention has the beneficial effects that:

according to the method and the device for biomass self-heating pyrolysis and bio-oil in-situ deoxidation, the biomass pyrolysis process and the calcium oxide carbonation reaction are organically combined, and heat released by the calcium oxide carbonation reaction is supplied to the biomass pyrolysis process in situ to absorb heat, so that the biomass self-heating pyrolysis is realized. Meanwhile, the calcium oxide can also absorb the carbon dioxide-like substances generated in the biomass pyrolysis process in situ, and the biological oil is promoted to be deoxidized and upgraded so as to realize high-quality utilization of the biological oil.

Drawings

FIG. 1 is a schematic diagram of an apparatus for autothermal pyrolysis of biomass and in-situ deoxygenation of bio-oil according to the present invention.

In the figure, 1, a biomass bin, 2, a calcium oxide bin, 3, a pyrolysis furnace, 4, a cyclone separator, 5, a calcining furnace, 6, a first heat exchanger, 7 and a second heat exchanger.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1, the apparatus for autothermal pyrolysis of biomass and deoxygenation of bio-oil designed by the present invention comprises: biomass silo 1, calcium oxide silo 2, pyrolysis furnace 3, cyclone 4, calciner 5, first heat exchanger 6 and second heat exchanger 7. In the present embodiment, the pyrolysis furnace 3 of biomass is a fluidized bed pyrolysis furnace; wherein, the solid inlet end of the pyrolysis furnace 3 is respectively connected with the solid outlets of the biomass bin 1, the calcium oxide bin 2 and the calcining furnace 5; the gas outlet end at the top of the pyrolysis furnace 3 is connected with the inlet end of the cyclone separator 4; rotary wrenchThe solid outlet end of the air separator 4 is connected with the solid inlet end of the calcining furnace 5, and the flue gas outlet end of the calcining furnace 5 is connected with the flue gas inlet end of the second heat exchanger 7; the gas outlet end of the cyclone 4 is connected to the pyrolysis gas flow inlet end of the first heat exchanger 6. The first heat exchanger 6 and the second heat exchanger 7 are connected in series through two gas paths, and CO is respectively arranged in the two gas paths₂Gas flow (CO)₂Or CO₂+N₂) And air; CO in two gas paths₂The airflow and the air enter the first heat exchanger 6 and the second heat exchanger 7 in sequence, and the flue gas of the pyrolysis gas and the calcining furnace 5 is fully utilized to carry out CO treatment₂The air stream and air are preheated. The preheated air enters the calcining furnace 5, and the preheated CO₂The gas stream enters the pyrolysis furnace 3. In the present embodiment, the first heat exchanger 6 and the second heat exchanger 7 employ shell-and-tube heat exchangers; the calciner 5 is a Loop-seal type furnace or other fixed bed or fluidized bed type furnaces.

Based on the biomass self-heating pyrolysis and bio-oil deoxidation device provided by the invention, the invention also designs a biomass self-heating pyrolysis and bio-oil in-situ deoxidation method, and the specific process of the method is as follows:

the calcium oxide-based adsorbent is added into the fluidized bed pyrolysis furnace 3 as fluidized bed materials in advance, and carbon dioxide and air enter the pyrolysis furnace 3 and the calcining furnace 5 respectively after being preheated by the first heat exchanger 6 and the second heat exchanger 7 respectively. The biomass is fed into the pyrolysis furnace 3 at a certain speed, the temperature of the pyrolysis furnace 3 is controlled at 500-700 ℃, the biomass thermally absorbs heat in the carbon dioxide atmosphere (namely pure carbon dioxide atmosphere or carbon dioxide-rich atmosphere), and the calcium oxide reacts with the introduced carbon dioxide gas flow to release heat. The heat absorption capacity in the biomass pyrolysis process is generally 0.8-1.6MJ/kg according to the difference of biomass raw materials, the average value is 1.2MJ/kg, namely the heat required by biomass pyrolysis per kilogram is 1.2 MJ. Calcium oxide reacts with carbon dioxide to produce calcium carbonate (CaO + CO)₂→CaCO₃) A great deal of heat (178.3kJ/mol) is released, and the heat release of the carbonation reaction of the calcium oxide is 3.18MJ/kg after conversion, namely 3.18MJ of heat can be released by each kilogram of calcium oxide through the carbonation reaction. According to this calculation, theoretically, 1kg of calcium oxide can be supplied per 0.38kg of carbonated calcium oxideThe heat required by the biomass pyrolysis process realizes the self-sustaining operation of the biomass pyrolysis process. The carbonation reaction of calcium oxide and the heat release thereof can be controlled by controlling the amount of carbon dioxide introduced into the pyrolysis furnace 3, thereby regulating the reaction temperature of the pyrolysis furnace 3.

Pyrolysis volatile components, pyrolysis coke and calcium carbonate generated by reaction generated by biomass pyrolysis are separated by the cyclone separator 4, and the obtained pyrolysis volatile components enter the heat exchanger 6 for condensation and cooling to generate pyrolysis gas and bio-oil. The separated solid pyrolytic coke and calcium carbonate enter a calcining furnace 5 to be calcined at the temperature of 800-950 ℃ in the air atmosphere, and the calcium oxide formed by regeneration is returned to the pyrolyzing furnace for recycling (CaCO)₃→CaO+CO₂). The calcium carbonate calcination decomposition is a strong endothermic reaction, and the heat required for the calcination decomposition of the calcium carbonate generated in the pyrolysis furnace is the same as the heat released in the previous carbonation process. According to the pyrolysis of 1kg of biomass, 0.38kg of calcium oxide is required for carbonation to provide heat, 0.68kg of calcium carbonate is generated, and 1.2MJ of heat is also required for calcination and decomposition of the calcium carbonate. Under the condition that the calcium oxide carbonation supplies heat for biomass pyrolysis in situ, the biomass is pyrolyzed to generate pyrolysis gas, pyrolysis coke and bio-oil, and the typical yield of biomass pyrolysis products is as follows: 25 wt.% pyrolysis gas, 25 wt.% pyrolysis coke, 50 wt.% bio-oil. At this time, the calorific value of the pyrolysis coke generated by the pyrolysis of 1kg of biomass is about 0.25kg × 26MJ/kg ═ 6.5MJ, which is much larger than 1.2MJ of the heat required for the calcination decomposition of calcium carbonate. Therefore, the heat released by the partial combustion of the pyrolysis coke may be sufficient to supply the heat required for the calcination decomposition process of calcium carbonate. In the actual production process, the addition amount of the carbon dioxide and the calcium oxide-based adsorbent and the proportion of the biomass can be adjusted according to the pyrolysis working condition so as to meet the requirement of self-sustaining heat in the pyrolysis process.

The calcium oxide-based adsorbent used in the invention is calcium oxide from various sources, as well as quicklime, calcined limestone or calcined dolomite.

The biomass self-heating pyrolysis method provided by the invention can realize the self-sustaining of energy in the biomass pyrolysis process, and the calcium oxide-based adsorbent can absorb carbon dioxide and other carbon dioxide substances generated by biomass pyrolysis in situ, such as carboxylic acid components and the like, so that the oxygen in the bio-oil is promoted to be removed in the form of carbon dioxide, and the high-quality utilization of the bio-oil is realized.

The above embodiments are only used for illustrating the design idea and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and implement the present invention accordingly, and the protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes and modifications made in accordance with the principles and concepts disclosed herein are intended to be included within the scope of the present invention.