A reaction system and method for producing CO-rich gas by catalytic cracking of biomass

Abstract

The present application relates to the field of biomass conversion, and particularly relates to a reaction system and method for preparing CO-rich gas by catalytic cracking of biomass. The reaction system comprises a cracking reactor, a catalytic reactor, a settler, a fast separator and a cyclone separator. The lower part of the catalytic reactor is connected with the cracking reactor, the upper part of the catalytic reactor is connected with the settler, the fast separator and the cyclone separator are arranged inside the settler, the fast separator is connected with the catalytic reactor, the lower part of the cyclone separator is arranged in the settler, the oil gas outlet is arranged in the upper part of the settler, the upper part of the cyclone separator is connected with the oil gas outlet, the upper part of the cyclone separator is provided with a solid phase outlet, and the solid phase outlet is arranged inside the settler. The lower part of the settler is provided with a spent catalyst outlet, and the lower part of the cracking reactor is provided with a biomass raw material inlet, a regenerated catalyst inlet and a lifting steam inlet. The reaction system can realize continuous and stable operation, has no pollution, has wide applicability, and has high CO content of the gas.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass thermochemical conversion, and in particular to a reaction system and method for producing CO-rich fuel gas through catalytic cracking of biomass. Background Art

[0002] Biomass is a renewable resource that can be directly burned or converted on a large scale to produce clean energy in liquid or gaseous forms. The development and utilization of biomass energy is a major topic of concern both domestically and internationally. Vigorously developing and utilizing biomass resources will contribute to the diversification of energy structures and the achievement of carbon peak and carbon neutrality.

[0003] Biomass thermochemical conversion technologies include dry distillation, pyrolysis gasification, and liquefaction, which aim to produce biochar, fuel gas, and pyrolysis oil, respectively. Pyrolysis gasification refers to the process by which the macromolecular structures in biomass undergo decomposition, fragmentation, or reformation at high temperatures to produce a lightweight, combustible gaseous fuel. Currently, pyrolysis gasification technologies mostly use air or steam as the gasifying agent, with gasification temperatures typically exceeding 800°C. The resulting gas has a calorific value of approximately 20% of that of natural gas and is used for power generation or heating, resulting in low added value. Choosing the right catalyst can not only effectively lower the gasification reaction temperature and reduce the manufacturing cost of the reaction unit, but also accelerate the reaction rate, resulting in better product selectivity, further improving the economic viability of pyrolysis gasification technology and expanding its application scenarios. Traditional biomass gasification systems suffer from high reaction temperatures and low product added value.

[0004] At present, how to convert biomass resources into higher value-added chemical products at low cost and high efficiency is the research focus and difficulty of many companies and research institutions at home and abroad. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a reaction system and method for producing CO-rich fuel gas by catalytic cracking of biomass.

[0006] In a first aspect, the present application provides a reaction system for preparing CO-rich gas by catalytic pyrolysis of biomass, comprising: a pyrolysis reactor 1, a catalytic reactor 2, a settler 3, a fast separator 5 and a cyclone separator 6; the lower part of the catalytic reactor 2 is connected to the pyrolysis reactor 1, the upper part of the catalytic reactor 2 is connected to the settler 3, the fast separator 5 and the cyclone separator 6 are arranged inside the settler 3, the fast separator 5 is connected to the catalytic reactor 2, the lower part of the cyclone separator 6 is arranged in the settler 3, an oil gas outlet 11 is arranged in the upper part of the settler 3, the upper part of the cyclone separator 6 is connected to the oil gas outlet 11, the upper part of the cyclone separator 6 is provided with a solid phase outlet, and the solid phase outlet is arranged inside the settler 3; the lower part of the settler 3 is provided with a spent catalyst outlet 7, and the lower part of the pyrolysis reactor 1 is provided with a biomass raw material inlet 8, a regenerated catalyst inlet 9 and a steam inlet 10. The reaction system of the present application can realize continuous and stable operation, is convenient to maintain, and mainly produces CO-rich gas, which can be used for hydrogen production, methanol production and the like, and the production process does not produce waste residue, waste water and waste gas. Moreover, the reaction system can process various types of biomass raw materials, has wide applicability, the CO content in the obtained CO-rich gas is not less than 30%, and the like. The biomass catalytic pyrolysis reaction is carried out in two reactors respectively, the pyrolysis reactor mainly undergoes rapid pyrolysis, the catalytic reactor realizes the best catalytic conditions, and the raw material pyrolysis efficiency and product selectivity can be improved; the deactivated catalyst is first separated from the reaction oil gas by the fast separator, the catalytic reaction is terminated in time, and the load of the cyclone separator is reduced; the settler is arranged at the upper part of the catalytic reactor, the operation speed is further reduced, the catalyst particles leaving the fast separator rely on gravity to move downward in the settler, the loss of the catalyst with the oil gas is reduced, and the production cost is reduced.

[0007] As preferred, a spent catalyst circulation pipe 4 is further included, one end of the spent catalyst circulation pipe 4 is connected to the lower part of the settler 3, and the other end of the spent catalyst circulation pipe 4 is connected to the catalytic reactor 2.

[0008] As preferred, the spent catalyst circulation pipe 4 is used for conveying the spent catalyst into the catalytic reactor 2. Further preferably, the connection position of the spent catalyst circulation pipe 4 to the catalytic reactor 2 is adjustable, and the spent catalyst circulation pipe 4 is preferably used for controlling the catalytic reaction space velocity. When the catalytic reaction depth control requirement is different due to different raw material compositions, the reaction depth can be adjusted by the spent catalyst circulation pipe to control the catalytic reaction space velocity. The present application finds that the above problems can be better solved by using the structure and connection mode of the spent catalyst circulation pipe 4.

[0009] Preferably, the cracking reactor 1 and the catalytic reactor 2 are both upward fluidized bed reactors, and the cracking reactor 1 and the catalytic reactor 2 are vertically connected structures.

[0010] Further preferably, the cracking reactor 1 is an ascending high space velocity fluidized bed reactor in which the raw material and the catalyst are mixed and lifted; the catalytic reactor 2 is an ascending low space velocity fluidized bed reactor in which the cracking gas, the catalyst and the circulating catalyst are mixed and lifted.

[0011] Further preferably, the settler 3 disposed above the catalytic reactor 2 is a container that meets the height requirements for gravity settling separation of catalyst particles. The settler 3 allows catalyst particles entrained in the oil and gas to be separated by gravity. The gas velocity in the settler is preferably no greater than 0.2 m / s.

[0012] Preferably, the quick separator 5 is a T-shaped quick separator.

[0013] More preferably, the T-shaped structure of the T-shaped quick separator has both ends pointing vertically downward. In the present invention, the quick separator is a T-shaped structure with both ends pointing vertically downward, which can quickly achieve gas and solid phase separation with a separation efficiency greater than 85%.

[0014] Preferably, the invention further comprises a regeneration catalyst inclined tube connected to the regeneration catalyst inlet 9, wherein the angle between the regeneration catalyst inclined tube and the vertical direction is not greater than 30 degrees.

[0015] Further preferably, the regenerated catalyst circulation pipe 4 is provided with an inclined pipe section, which is located at the connection with the catalytic reactor 2 and the settler 3, and the angle between the inclined pipe section and the vertical direction is no greater than 30 degrees. The present invention has found that when the angle between the inclined pipe sections of the regenerated catalyst inclined pipe and the regenerated catalyst circulation pipe and the vertical direction is no greater than 30 degrees, the effect is better.

[0016] Preferably, the rear end of the oil and gas outlet 11 is connected to a product separation system to collect carbon monoxide-rich gas products and liquid products; the lifting steam inlet 10 is arranged at the bottom of the cracking reactor 1, the regeneration catalyst inlet 9 is arranged above the lifting steam inlet 10, and the biomass raw material inlet 8 is arranged above the regeneration catalyst inlet 9.

[0017] According to the present invention, it can be understood that in addition to the main static equipment such as cracking reactor, catalytic reactor, settler, rapid separator, etc., the system of the present invention can also be equipped with dynamic equipment such as pumps, compressors, fans, etc. that are conventionally set in the art.

[0018] In a second aspect, the present invention provides a method for producing CO-enriched fuel gas by catalytic cracking of biomass, which uses the aforementioned reaction system for producing CO-enriched fuel gas by catalytic cracking of biomass.

[0019] As preferred, the method for preparing CO-rich gas by catalytic pyrolysis of biomass comprises the following steps: biomass raw material is mixed with catalyst in the lower part of a pyrolysis reactor 1 to carry out a pyrolysis reaction, and the pyrolysis reaction product is introduced into a catalytic reactor 2 to carry out a catalytic reaction, and the catalytic product is introduced from the top of a settler 3 into a product separation system after passing through a rapid separator 5 and a cyclone 6, and the product separation and collection are carried out, and the solid phase is discharged from the bottom of the settler 3; preferably, the solid phase is introduced into a regenerator to carry out a coking regeneration, and the regenerated catalyst is mixed with the biomass raw material in the lower part of the pyrolysis reactor 1 to carry out a pyrolysis reaction. The operation method of the biomass pyrolysis reaction system provided by the present application is as follows: the biomass raw material is mixed with catalyst to carry out a pyrolysis reaction, the pyrolysis reaction product is introduced into a catalytic reactor to carry out a catalytic reaction, the catalytic product is introduced from the top of a settler after passing through a rapid separator and a cyclone into a subsequent product separation system, and the product separation and collection are carried out; the solid phase including deactivated catalyst is discharged from the bottom of the settler and introduced into a regenerator to carry out a coking regeneration, and the regenerated catalyst is lifted from the lower part of the pyrolysis reactor by lifting steam and uniformly mixed with the biomass raw material to carry out a pyrolysis reaction again.

[0020] As preferred, when the depth of catalytic reaction is required to be controlled due to different raw material compositions, the depth of reaction is adjusted by a circulating pipe of the spent catalyst to control the space velocity of the catalytic reaction.

[0021] Further preferably, the biomass raw material is in the form of particles, and the water content of the particles is less than 15wt%, and preferably, more than 70% of the particles have a particle size of 150-250 microns. It is found by the present application that the structure, particle size and water content of the biomass raw material as described above can make the subsequent reaction more effective.

[0022] According to the method for preparing CO-rich gas by catalytic pyrolysis of biomass, the operating pressure in the pyrolysis reactor and / or the catalytic reactor is 0.1-0.5MPa, the operating temperature is 400-650℃, the average operating gas velocity is 2-22m / s, the pyrolysis reaction time is 1-3s, the catalytic reaction time is 3-6s, the pyrolysis reaction weight hourly space velocity is 160-250h -1 , the catalytic reaction zone weight hourly space velocity is 60-100h -1 , the raw material feeding linear velocity is 0.5-1.5m / s, and the mass ratio of the biomass raw material to the regenerated catalyst is 1:2-1:10; the temperature of the regenerated catalyst introduced into the pyrolysis reactor is not less than 590℃.

[0023] As preferred, the reaction temperature and reaction time need to be controlled during the cracking reaction, and the reaction time is mainly controlled in the catalytic reaction, and the preferred reaction conditions are further controlled: the mass ratio of the biomass raw material to the catalyst is 1:5-7, and the reaction time is 2±1s; the mass ratio of the oil gas to the catalyst in the catalytic reactor 2 is 1:9-11, and the reaction time is 4±1s. Under the above operation conditions, the biomass raw material is better to perform the catalytic cracking reaction under the action of the catalyst. The reaction product enters the rapid separator 5 to separate the oil gas and the catalyst, more than 85wt% of the deactivated catalyst is separated from the oil gas, and the rest enters the cyclone separator 6 with the oil gas to be further separated. The settler 3 makes the catalyst perform the settling separation in the space with the operation gas speed lower than 0.2m / s, so as to reduce the loss amount of the catalyst with the oil gas. The reaction oil gas leaves the reaction system from the outlet 11 at the top of the settler, and enters the system product separation to obtain the carbon monoxide-rich gas.

[0024] Further preferably, in the cracking reactor and / or the catalytic reactor, the operation pressure is 0.25MPa, the operation temperature is 400-550℃, the average operation gas speed is 13-15m / s, the cracking reaction time is 2.0s, the catalytic reaction time is 4.0s, the cracking reaction weight hourly space velocity is 170h -1 , the catalytic reaction zone weight hourly space velocity is 60h -1 , the raw material feeding linear speed is 1.2m / s, and the mass ratio of the biomass raw material to the catalyst is 1:6.

[0025] The present application has at least the following beneficial effects:

[0026] 1. The biomass catalytic cracking reaction system can be used for treating agricultural wastes such as straw and rice husk, garden wastes, forestry processing residues and various types of biomass raw materials, and can also be used for treating mixtures of various biomass raw materials, and has wide applicability. The carbon monoxide content in the obtained carbon monoxide-rich gas is not less than 30%.

[0027] 2. The biomass catalytic cracking reaction is performed in two reactors respectively, the cracking reactor mainly performs the rapid cracking reaction, and the catalytic reactor mainly realizes the best catalytic conditions by reducing the space velocity, so as to improve the cracking efficiency of the raw material and the product selectivity.

[0028] 3. The deactivated catalyst is first separated from the reaction oil gas through the T-shaped rapid separator, the catalytic reaction is timely terminated, and the load of the cyclone separator is reduced.

[0029] 4. The settler is arranged at the upper part of the catalytic reactor, the operation speed is further reduced, the catalyst particles leaving the rapid separator are lowered by gravity in the settler, the loss amount of the catalyst with the oil gas is reduced, and the production cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 This is a schematic diagram of the reaction system for producing CO-rich fuel gas by catalytic cracking of biomass according to the present invention.

[0032] Reference numerals:

[0033] 1- cracking reactor; 2- catalytic reactor; 3- settler;

[0034] 4-regenerated catalyst circulation pipe; 5-quick separator; 6-cyclone separator;

[0035] 7-export of catalyst to be regenerated; 8-inlet of biomass raw materials; 9-inlet of regenerated catalyst;

[0036] 10- Lifting steam inlet; 11- Oil and gas outlet. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0038] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0039] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "first" and "second" are used to clearly illustrate the numbering of product components and do not represent any substantial difference. "Up," "down," "inside," etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0040] Example 1

[0041] like Figure 1As shown, this embodiment provides a reaction system for producing CO-rich fuel gas through catalytic cracking of biomass. Its main static equipment includes: a cracking reactor 1, a catalytic reactor 2, a settler 3, a rapid separator 5, and a cyclone separator 6. The rapid separator 5 is a T-shaped rapid separator, with both ends of the T-shaped structure pointing vertically downward. The lower portion of the cracking reactor 1 is equipped with: a biomass feedstock inlet 8, a regenerated catalyst inlet 9, and a lift steam inlet 10. The catalytic reactor 2 is connected to the cracking reactor 1 at the bottom and to the settler 3 and the rapid separator 5 at the top. The settler 3 includes the rapid separator 5 and the cyclone separator 6. The lower portion of the settler 3 is equipped with an outlet 7 for regenerated catalyst and an outlet 4 for regenerated catalyst circulation pipe. The top of the settler 3 is equipped with an oil and gas outlet 11. A regenerated catalyst inclined pipe is connected to the regenerated catalyst inlet 9, and the angle between the regenerated catalyst inclined pipe and the vertical direction is no more than 30 degrees. The catalyst circulation pipe 4 to be regenerated is provided with an inclined pipe section, which is provided at the connection between the catalytic reactor 2 and the settler 3 , and the angle between the inclined pipe section and the vertical direction is not greater than 30 degrees.

[0042] This embodiment also provides an operating method for producing carbon monoxide-rich fuel gas using biomass as a raw material using the reaction system as follows:

[0043] The biomass is crushed into biomass raw material particles, wherein more than 70 wt% of the particles have a particle size within the range of 150 to 250 microns; and the water content of the biomass raw material is reduced to less than 15 wt% by drying.

[0044] The crushed and dried biomass particles enter the lower portion of the cracking reactor 1 through biomass feed inlet 8, with a feed velocity of 0.5-1.5 m / s. The operating pressure of the cracking reactor 1 is 0.1-0.5 MPa (gauge pressure), the operating temperature is 550°C, and the average operating gas velocity is 13-15 m / s. The regenerated catalyst enters the lower portion of the cracking reactor 1 through inlet 9, with a temperature of no less than 590°C upon entry. The biomass feedstock to catalyst mass ratio is 1:6, and the reaction time is 2 seconds. The cracked oil and gas to catalyst mass ratio in the catalytic reactor 2 is 1:10, and the reaction time is 4 seconds. Under these operating conditions, the feedstock undergoes a catalytic cracking reaction under the action of the catalyst. The reaction products enter the rapid separator 5 for separation of the oil and gas from the catalyst. More than 85 wt% of the deactivated catalyst is separated from the oil and gas, with the remainder entering the cyclone separator 6 for further separation. The function of the settler 3 is to allow the catalyst to settle and separate in a space with an operating gas velocity below 0.2 m / s, thereby reducing catalyst loss with the oil and gas. The reaction oil and gas leave the reaction system from the outlet 11 at the top of the settler, and are separated into carbon monoxide-rich fuel gas after system product separation, with a carbon monoxide content higher than 30%.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for producing CO-rich fuel gas by catalytic cracking of biomass, characterized in that: The following steps are involved: The biomass raw material is mixed with the catalyst in the lower part of the cracking reactor to undergo cracking reaction to obtain cracking reaction products. The cracking reaction products enter the catalytic reactor for catalytic reaction. The catalytic products pass through the rapid separator and cyclone separator and enter the product separation system from the top of the settler for product separation and collection. The solid phase is discharged from the bottom of the settler. The solid phase enters the regenerator for char regeneration to obtain a regenerated catalyst, and the regenerated catalyst is mixed with the biomass raw material from the lower part of the cracking reactor to undergo cracking reaction; When the requirements for catalytic reaction depth control vary due to different raw material compositions, the reaction depth is adjusted through the regenerated catalyst circulation tube to control the catalytic reaction space velocity; The biomass raw material is in the form of particles, the moisture content of the particles is less than 15 wt %, and more than 70% of the particles have a particle size of 150 to 250 microns; The mass ratio of the biomass raw material to the catalyst is 1:5-7, and the cracking reaction time is 1-3s; the mass ratio of the cracked oil and gas to the catalyst in the catalytic reactor is 1:9-11, and the catalytic reaction time is 4±1s; in the cracking reactor and / or the catalytic reactor, the operating pressure is 0.25MPa, the operating temperature is 400-550°C, the average operating gas velocity is 13-15m / s, the cracking reaction time is 2.0s, the catalytic reaction time is 4.0s, and the cracking reaction weight hourly space velocity is 170h -1 , the weight hourly space velocity in the catalytic reaction zone is 60h -1 , the feed linear velocity of the raw material was 1.2 m / s, and the mass ratio of the biomass raw material to the catalyst was 1:6; The biomass catalytic cracking reaction system for producing CO-rich fuel gas includes: a cracking reactor, a catalytic reactor, a settler, a rapid separator and a cyclone separator; The lower part of the catalytic reactor is connected to the cracking reactor, the upper part of the catalytic reactor is connected to the settler, the quick separator and the cyclone separator are arranged inside the settler, the quick separator is connected to the catalytic reactor, the lower part of the cyclone separator is arranged in the settler, the oil and gas outlet is arranged at the upper part of the settler, the upper part of the cyclone separator is connected to the oil and gas outlet, the upper part of the cyclone separator is provided with a solid phase outlet, and the solid phase outlet is located inside the settler; the lower part of the settler is provided with an outlet for regenerated catalyst, and the lower part of the cracking reactor is provided with a biomass raw material inlet, a regenerated catalyst inlet and a lifting steam inlet; it also includes a regenerated catalyst inclined pipe connected to the regenerated catalyst inlet, the angle between the regenerated catalyst inclined pipe and the vertical direction is not greater than 30 degrees; the regenerated catalyst circulation pipe is provided with an inclined pipe section, the inclined pipe section is provided at the connection with the catalytic reactor and the settler, and the angle between the inclined pipe section and the vertical direction is not greater than 30 degrees; The biomass catalytic cracking reaction system for producing CO-rich fuel gas further includes a circulating pipe for a catalyst to be generated, one end of which is connected to the lower part of the settler, and the other end of which is connected to the catalytic reactor. Both the cracking reactor and the catalytic reactor are upward fluidized bed reactors, and the cracking reactor and the catalytic reactor are vertically connected in an upper and lower direction. The quick separator is a T-type quick separator, and both ends of the T-type structure of the T-type quick separator are vertically downward.

Images