Fluidized gasification-pyrolysis conveying coupled reaction device
By coupling the bubble fluidized bed with the two-stage conveyor, the fluidized wind speed and feed volume are controlled, and the problem of difficult to take into account the residence time and flow rate of the materials in the gas-solid fluidized bed reactor is achieved, and efficient and economical integration of material pyrolysis and transportation is achieved, and it is suitable for compact gasification reaction devices.
Patent Information
- Application Number
- CN202510936062.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-08
- Publication Date
- 2025-08-15
AI Technical Summary
The prior art is difficult to simultaneously control the residence time and flow rate of materials in gas-solid fluidized bed reactors, resulting in unstable reactors, high investment and large energy consumption, and it is impossible to achieve efficient, economical and safe pyrolysis and transportation of materials.
The bubble fluidized bed is coupled with the two-stage conveyor. By controlling the fluidized wind speed and feed quantity, fine particles enter the conveyor I, coarse particles enter the conveyor II, adjust the gas-solid ratio, control the residence time and flow rate of the material in the reactor, and realize the integration of pyrolysis and transportation.
Effectively control the flow rate and residence time of solid materials, the structure is simple and compact, which reduces initial investment, improves gas-solid contact efficiency, enhances pyrolysis effect, and is suitable for compact and efficient gasification reactions.
Smart Images
Figure CN120479313A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a fluidized bed device in an energy chemical process, and in particular to a fluidized gasification-pyrolysis-transport coupled reaction device. Background Art
[0002] The bubbling fluidized bed reactor is a classic gas-solid two-phase fluidized bed reactor widely used in industry. It is valued for its sufficient gas-solid contact, long particle residence time, and strong heat and mass transfer properties. Material flow rate is typically controlled by adjusting the screw feeder speed, which increases the screw feeder's size, leading to increased construction costs and the risk of instability. Pneumatic conveying systems, on the other hand, operate at higher gas velocities. During operation, the material within the pneumatic conveying system is rapidly carried out of the bed at high gas velocities, eliminating particle accumulation at the bottom of the bed. Pneumatic conveying systems offer high external recirculation flow rates and minimal gas-solid backmixing, and have recently been applied in fields such as coal gasification and chemical looping combustion. However, they also have several drawbacks: Due to the high operating air velocity, the reactor is typically tall to ensure sufficient material residence time, resulting in a less compact layout and high initial investment. Furthermore, the high air velocity throughout the entire height of the pneumatic conveying system results in high fan energy consumption, reducing the economic efficiency of the reactor operation. Whether using a bubbling fluidized bed, a circulating fluidized bed, or other gas-solid fluidized beds derived from these, it's difficult to achieve both a high residence time and a high material flow rate. Reactors with longer residence times often have lower material flow rates, while reactors with higher material flow rates often have insufficient particle residence time. To date, no technology has been reported that can simultaneously control the residence time of the material within the reactor, adjust the reactor's circulation flow rate, enhance char pyrolysis, and ensure efficient, economical, and safe operation. Summary of the Invention
[0003] The purpose of the present invention is to provide a fluidized gasification-pyrolysis transport coupled reaction device, which can grade the semi-coke produced by the bubbling fluidized bed into a pneumatic conveyor according to its size, thereby improving the flow rate and reactivity of the semi-coke.
[0004] To achieve the above-mentioned object, the technical solution adopted by the present invention is: a fluidized gasification-pyrolysis conveying coupled reaction device, the reaction device comprising a wind chamber, an air distribution plate, a bubbling fluidized bed reactor, a transition section, a conveyor I, a screw feeder, a conveyor II and a gasifier;
[0005] The material outlet of the spiral feeder is connected to one side end of the bubbling fluidized bed reactor, the other side end of the bubbling fluidized bed reactor is connected to the conveyor I through the conveyor II, the bottom end of the bubbling fluidized bed reactor is connected to the top of the wind chamber, the air distribution plate is arranged between the bubbling fluidized bed reactor and the wind chamber, the top of the bubbling fluidized bed reactor is connected to the conveyor I through the transition section, and the end of the conveyor I is connected to the inlet of the gasifier.
[0006] Furthermore, the upper part of the bubbling fluidized bed reactor body is a dilute phase zone, the lower part is a dense phase zone, and the lower part of the dense phase zone is an air distribution plate.
[0007] Furthermore, a fluidizing air inlet is provided on the bottom wall of the wind chamber, and the fluidizing air introduced is one or more of air, oxygen, water vapor and carbon dioxide.
[0008] Furthermore, the fluidizing air is a mixed gas of CO2 and O2, wherein the air equivalence ratio is 0.1 to 0.4 and the carbon dioxide concentration is 20% to 50%.
[0009] Furthermore, the head end of the conveyor I is connected to the transition section at the top, and then the conveyor I moves downward along one side of the bubbling fluidized bed reactor, and finally the tail end is connected to the inlet of the gasifier; the outlet end of the conveyor II is connected to the descending section of the conveyor I.
[0010] Furthermore, the material outlet height of the screw feeder is higher than the inlet height of the conveyor II.
[0011] Furthermore, the conveyor II is tilted downward by 5 to 60 degrees, and the inlet height of the conveyor II is higher than the initial bed material accumulation height in the bubbling fluidized bed reactor; the initial bed material is one or more of quartz sand, dolomite and olivine.
[0012] Furthermore, the conveyor I and the conveyor II are pipes lined with a high-temperature wear-resistant coating, and the pipe diameters of the conveyors I and II are smaller than the pipe diameter of the bubbling fluidized bed reactor.
[0013] Furthermore, the wind speed in the conveyor I is 5-20 m / s, the temperature is 400-600° C., the particle speed is 5-25 m / s, the gas-solid ratio is 15-30, and the gas-solid ratio in the conveyor II is 0-15.
[0014] Furthermore, the fluidization wind speed of the bubbling fluidized bed reactor is 1 to 3.5 m / s, the temperature is 700 to 1000° C., and the operating pressure is a slight positive pressure of 40 to 60 kPa or a pressurized pressure of 0 to 4 MPa.
[0015] Furthermore, the bubbling fluidized bed reactor adopts a bubbling bed or turbulent bed operation mode, and the conveyor I adopts a pneumatic conveying or fast fluidized bed operation mode.
[0016] Compared with the prior art, the present invention has the following beneficial effects:
[0017] (1) Effectively control the flow rate of solid materials and the residence time of materials in the reactor. Compared with the traditional gas-solid fluidized bed reactor, the present invention couples the bubbling fluidized bed and the two-stage conveyor, thereby having the advantages of the long residence time of particles in the bubbling fluidized bed and the characteristics of the large particle flow rate of the pneumatic conveying device. The residence time of fine particles in the bubbling fluidized bed reactor is greater than 40s, and coarse particles enter the conveyor through the pressure difference and back mixing. In the device of the present invention, the fluidizing air enters the bubbling fluidized bed reactor from the wind chamber through the air distribution plate, and then enters the conveyor I through the transition section. The diameter of the high-temperature wear-resistant coating pipe of conveyors I and II is smaller than the diameter of the fluidized bed reactor, so that the wind speed in conveyors I and II is greater than the wind speed in the fluidized bed reactor section. The material enters the bubbling fluidized bed reactor from a screw feeder. The terminal velocity of particles with smaller particle sizes (the final velocity at which particles freely settle in the airflow) is much lower than the fluidizing wind speed, so they will be entrained by the fluidizing wind into conveyor I. The terminal velocity of particles with larger particle sizes is higher than the fluidizing wind speed and cannot be carried away by the fluidizing wind. They will enter conveyor II due to the back mixing and pressure difference of the fluidized bed.
[0018] The minimum fluidizing velocity is determined based on the bed pressure drop. By reducing the feed rate and increasing the velocity to achieve the entrainment velocity, the fluidizing velocity is adjusted to a level between the terminal velocities of smaller and larger particles, allowing fine semi-coke to be blown from the top of the bubbling fluidized bed reactor into conveyor I. Therefore, while maintaining a constant oxygen concentration in the oxidation reaction, by controlling the feed rate of the screw feeder and the velocity of the fluidizing air entering the fluidized bed to a range of 1 to 3.5 m / s, the flow rate of the solid material in the device and the residence time of the material within the reactor can be flexibly and effectively controlled.
[0019] (2) Effectively realize the integration of material pyrolysis and transportation. Compared with traditional gasification devices, the device of the present invention realizes the integration of pyrolysis and transportation of semi-coke particles by coupling two sections of conveyors. It has the advantages of long residence time of particles in the bubbling fluidized bed and sufficient gas-solid contact, as well as high external circulation flow rate and sufficient pyrolysis of semi-coke particles. In the device of the present invention, the material undergoes pyrolysis reaction in the bubbling fluidized bed reactor, which effectively prolongs the gas-solid contact time and enhances the gas-solid contact efficiency; the material residue after pyrolysis is transported by the conveyor and transferred to the next stage high-temperature gasification furnace, which is more conducive to the gasification reaction. The gasification reaction temperature of the bubbling fluidized bed is 700-1000℃, and the reaction temperature of conveyors I and II is 500-800℃. Therefore, the effective pyrolysis of the material is achieved by the bubbling fluidized bed, and the pyrolysis residue is transported by the conveyor, which can effectively realize the integrated control of material pyrolysis and transportation.
[0020] (3) Simple and compact structure. The reaction device of the present invention consists of a wind chamber, an air distribution plate, a bubbling fluidized bed reactor, a transition section, a conveyor I, a cyclone separator, a conveyor II, and a high-temperature gasification furnace. It has a simple structure, a low overall height, a compact space layout, a small initial investment, and good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is a structural schematic diagram of the present invention.
[0022] Markings in the figure are: 1-wind chamber, 2-air distribution plate, 3-bubbling fluidized bed reactor, 4-transition section, 5-conveyor I, 6-screw feeder, 7-conveyor II, 8-gasifier. DETAILED DESCRIPTION
[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0024] like Figure 1 As shown, a fluidized gasification-pyrolysis transport-coupled reaction device of the present invention comprises a wind chamber 1, an air distribution plate 2, a bubbling fluidized bed reactor 3, a transition section 4, a conveyor I5, a screw feeder 6, a conveyor II7, and a gasifier 8. The material outlet of the screw feeder 6 is connected to one end of the bubbling fluidized bed reactor 3, and the other end of the bubbling fluidized bed reactor 3 is connected to the conveyor I5 via the conveyor II7. Material enters the bubbling fluidized bed reactor 3 through the screw feeder 6. Fine particles, under the influence of the fluidizing air, pass through the transition section 4 and enter the conveyor I5. Coarse particles, under the influence of the pressure difference, pass through the conveyor II7 and fall directly into the conveyor I5. The bottom end of the bubbling fluidized bed reactor 3 is connected to the top end of the wind chamber 1, and the top end of the bubbling fluidized bed reactor 3 is connected to the conveyor I5 via the transition section 4. The bubbling fluidized bed reactor 3 can operate in a bubbling bed or turbulent bed mode. The conveyor I5 can operate in a pneumatic conveying or fast fluidized bed mode. The air distribution plate 2 is connected between the bubbling fluidized bed reactor 3 and the wind chamber 1. A fluidizing air inlet is provided on the wall of the wind chamber 1. Fluidizing air enters the wind chamber 1 through the fluidizing air inlet and then passes through the air distribution plate 2 into the bubbling fluidized bed reactor 3.
[0025] Preferably, the flow rate of the bubbling fluidized bed reactor 3 is less than the flow rate of the conveyor I5, thereby increasing the particle speed in the conveyor I5 and facilitating it to achieve a state of pneumatic conveying or rapid fluidization.
[0026] Preferably, the material outlet height of the spiral feeder on the left side of the bubbling fluidized bed reactor 3 is higher than the inlet height of the conveyor II7, the conveyor II7 is inclined downward by 5 to 60 degrees, and the inlet height of the conveyor II7 is higher than the initial bed material accumulation height in the bubbling fluidized bed reactor, so that the material can enter the conveyor I5 under the action of back mixing and pressure difference after being pyrolyzed for a certain period of time in the bubbling fluidized bed reactor.
[0027] The working process of the fluidized gasification-pyrolysis conveying coupled reaction device of the above structure is: the material enters the bubbling fluidized bed reactor 3 from the screw feeder 6, the fluidizing air coming out of the wind chamber 1 enters the bubbling fluidized bed reactor 3 through the air distribution plate 22, and fluidizes the solid material in the bubbling fluidized bed reactor 3, so that it is in a bubbling fluidization or turbulent fluidization state, and the preliminary pyrolysis of the material is completed in the bubbling fluidized bed reactor 3; the bubbling fluidized bed reactor 3 is connected to the conveyor I5 through the transition section 4, and the fine particles in the material pass through the transition section 4 into the conveyor I5 section under the action of the fluidizing air, and the coarse particles in the material enter the conveyor II7 under the action of the pressure difference and the fluidized bed back mixing, and the conveyor I5 is in a pneumatic conveying or rapid fluidization state; the conveyor I5 is connected to the gasifier 8, and the next gasification reaction is completed in the gasifier.
[0028] The working principle of the fluidized gasification-pyrolysis transport coupled reaction device of the above structure is: when the device is in operation, by controlling the wind speed of the fluidizing air entering the bubbling fluidized bed reactor 3 and the feeding amount of the spiral feeder 6, the material is in a bubbling fluidized state and a turbulent fluidized state in the bubbling fluidized bed reactor 3, and under the action of pressure difference and back mixing, it enters the conveyor I5 from the conveyor II7 on the left side of the bubbling fluidized bed reactor 3.
[0029] The fluidized gasification-pyrolysis-transport coupling reaction device of this structure controls the amount of solid material entering the conveyor I5 from the bubbling fluidized bed reactor 3 by changing the wind speed of the fluidizing air and the feeding amount of the spiral feeder 6. The gas-solid ratio in the conveyor I5 is maintained in the range of 15-30 through the combined adjustment of the wind speed and the feeding amount. The wind speed of the fluidizing air is maintained between the minimum fluidization velocity and the entrainment velocity to ensure stable transportation without deposition, thereby effectively controlling the flow rate and residence time of the solid material in the gas-solid reaction device, and realizing the organic unity of pyrolysis and transportation, which is more conducive to the next gasification reaction.
[0030] An embodiment is listed below, in which the fluidized gasification-pyrolysis and transportation coupling reaction device of the present invention is applied to a disposal system for pyrolysis and transportation of organic solid waste formed particles, which includes a wind chamber 1, an air distribution plate 2, a bubbling fluidized bed reactor 3, a transition section 4, a conveyor I5, a screw feeder 6, a conveyor II7 and a gasifier 8. The material outlet of the screw feeder 6 is connected to the bubbling fluidized bed reactor 3 through the conveyor II7, and the bubbling fluidized bed reactor 3 is connected to the conveyor I5 through the conveyor II7. The formed particles (equivalent diameter <30mm) enter the bubbling fluidized bed reactor 3 through the screw feeder 6, and the fine particles (equivalent diameter <1000μm) enter the conveyor I5 through the transition section 4 under the action of fluidizing air. The coarse particles (equivalent diameter <2mm) fall directly into the conveyor I5 through the conveyor II7 under the action of pressure difference and back mixing. The bottom end of the bubbling fluidized bed reactor 3 is connected to the top end of the wind chamber 1. The top end of the bubbling fluidized bed reactor 3 is connected to the conveyor I5 via a transition section 4. The conveyor I5 is connected to the inlet of the gasifier 8. The bubbling fluidized bed reactor 3 can operate in either a bubbling bed or a turbulent bed mode. The conveyor I5 can operate in either a pneumatic conveying or a fast fluidized bed mode. An air distribution plate 2 is connected between the bubbling fluidized bed reactor 3 and the wind chamber 1. A fluidizing air inlet is provided on the wall of the wind chamber 1. The fluidizing air enters the wind chamber 1 through the fluidizing air inlet and then passes through the air distribution plate 2 into the bubbling fluidized bed reactor 3. The pyrolysis temperature of the bubbling fluidized bed reactor 3 is 700-1000°C. The operating temperatures of the conveyors I5 and II7 are 500-800°C. The operating temperature of the gasifier 8 is 1000-1600°C. The operating pressure of the bubbling fluidized bed reactor 3 is slightly positive pressure (40-60 kPa) or pressurized (-4 MPa).
[0031] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the scope of protection of the present invention in any form. All technical solutions obtained by equivalent substitution, etc., fall within the scope of protection of the present invention. Parts not covered by the present invention are the same as the existing technology or can be implemented using existing technology.
Claims
1. A fluidized gasification-pyrolysis transport coupled reaction device, characterized in that: The reaction device comprises a wind chamber (1), an air distribution plate (2), a bubbling fluidized bed reactor (3), a transition section (4), a conveyor I (5), a screw feeder (6), a conveyor II (7) and a gasifier (8); The material outlet of the spiral feeder (6) is connected to one side end of the bubbling fluidized bed reactor (3), and the other side end of the bubbling fluidized bed reactor (3) is connected to the conveyor I (5) through the conveyor II (7). The bottom end of the bubbling fluidized bed reactor (3) is connected to the top end of the wind chamber (1). The air distribution plate (2) is arranged between the bubbling fluidized bed reactor (3) and the wind chamber (1). The top end of the bubbling fluidized bed reactor (3) is connected to the conveyor I (5) through the transition section (4), and the end of the conveyor I (5) is connected to the inlet of the gasifier (8).
2. The fluidized gasification-pyrolysis-transport coupled reaction device according to claim 1, characterized in that: The upper part of the bubbling fluidized bed reactor (3) body is a dilute phase zone, the lower part is a dense phase zone, and the lower part of the dense phase zone is an air distribution plate (2).
3. The fluidized gasification-pyrolysis-transport coupled reaction device according to claim 1, characterized in that: The bottom wall of the wind chamber (1) is provided with a fluidizing air inlet, and the fluidizing air introduced is one or more of air, oxygen, water vapor and carbon dioxide.
4. The fluidized gasification-pyrolysis-transport coupled reaction device according to claim 3, characterized in that: The fluidizing air is a mixed gas of CO2 and O2, wherein the air equivalent ratio is 0.1-0.4 and the carbon dioxide concentration is 20%-50%.
5. The fluidized gasification-pyrolysis-transport coupled reaction device according to claim 1, characterized in that: The head end of the conveyor I (5) is connected to the transition section (4) located at the top, and then the conveyor I (5) moves downward along one side of the bubbling fluidized bed reactor (3), and finally the tail end is connected to the inlet of the gasifier (8); the outlet end of the conveyor II (7) is connected to the descending section of the conveyor I (5).
6. The fluidized gasification-pyrolysis-transport coupled reaction device according to claim 1, characterized in that: The material outlet height of the screw feeder (6) is higher than the inlet height of the conveyor II (7).
7. The fluidized gasification-pyrolysis-transport coupled reaction device according to claim 1, characterized in that: The conveyor II (7) is tilted downward by 5 to 60 degrees, and the inlet height of the conveyor II (7) is higher than the initial bed material accumulation height in the bubbling fluidized bed reactor.
8. The fluidized gasification-pyrolysis-transport coupled reaction device according to claim 1, characterized in that: The conveyor I (5) and the conveyor II (7) are pipes lined with a high-temperature wear-resistant coating, and the pipe diameters of the conveyors I and II are smaller than the pipe diameter of the bubbling fluidized bed reactor.
9. The fluidized gasification-pyrolysis-transport coupled reaction device according to claim 1, characterized in that: The wind speed in the conveyor I (5) is 5-20 m / s, the temperature is 400-600°C, the particle speed is 5-25 m / s, the gas-solid ratio is 15-30, and the gas-solid ratio in the conveyor II (7) is 0-15.
10. The fluidized gasification-pyrolysis-transport coupled reaction device according to claim 1, characterized in that: The fluidization wind speed of the bubbling fluidized bed reactor (3) is 1-3.5 m / s, the temperature is 700-1000° C., and the operating pressure is a slight positive pressure of 40-60 kPa or a pressurized pressure of 0-4 MPa.