CN113684064B - Fluidized bed gasification furnace - Google Patents

Abstract

The invention relates to the technical field of gasifiers, and discloses a fluidized bed gasifier which comprises a gasifier body and an air inlet, wherein the air inlet is positioned at the bottom of the gasifier body, an air cavity is formed in the side wall of the bottom of the gasifier body, an air inlet pipeline is arranged at the bottom of the air cavity, and the other end of the air inlet pipeline is communicated to one side of the air inlet. According to the invention, the air cavity and the air inlet pipeline are arranged in the furnace body, the temperature change of the oxidation area is checked through the temperature control device on the air inlet pipeline, when the temperature of the oxidation area exceeds the melting point of most ash, the air inlet pipe is opened through the change of the state of the phase change substance in the piston cavity, so that the gasifying agent originally in the bottom oxidation area is divided into two parts, the occurrence of bottom oxidation reaction is slowed down, the heat release of the oxidation area is reduced, and meanwhile, the low-temperature gasifying agent is utilized to absorb heat outside the oxidation area, so that the temperature of the oxidation area is reduced, the adhesion of ash is avoided, and the probability of coking at the bottom of the furnace is reduced.

Description

A fluidized bed gasifier

Technical field

The invention relates to the technical field of gasifiers, specifically a fluidized bed gasifier.

Background technique

The fluidized bed gasifier mainly uses the cone-shaped air distribution at the bottom of the furnace body to blow the pulverized coal inside the furnace body so that it is suspended in the air flow. The oxygen-rich air gasification agent and the pulverized coal are oxidized to make it The gas used for combustion is generated. The oxidation reaction mainly occurs at the bottom of the furnace body. The air flow goes up, driving the pulverized coal to circulate upward, producing combustible gas and semi-coke. The semi-coke returns to the furnace body for secondary reaction through the return device. Combustible gases must be dusted before use.

In a fluidized bed gasifier, large particles of semi-coke are generally produced at the bottom of the furnace body, and the ash content is high. The bottom is a high-temperature area. Once the oxidation reaction at the bottom is excessive, it is easy to cause the ash to reach the melting point, causing the ash content to reach the melting point. Coking adheres to the bottom of the furnace. At the same time, the product in the upper part of the furnace is small particles of semi-coke. Due to its small size and light weight, the small particles of semi-coke are easily discharged with the combustible gas and will not return to the return device, causing Pulverized coal is wasted.

Contents of the invention

In view of the shortcomings in the use of the existing fluidized bed gasifier proposed in the background technology, the present invention provides a fluidized bed gasifier, which has the characteristics of reducing the probability of coking at the bottom of the gasifier and reducing small particle semi-coke. It has the advantages of reducing waste and improving the utilization rate of pulverized coal, and solves the problems raised in the above background technology.

The present invention provides the following technical solution: a fluidized bed gasifier, including a furnace body and an air inlet. The air inlet is located at the bottom of the furnace body. A gas chamber is provided on the side wall of the bottom of the furnace body. There is an air inlet pipe at the bottom of the cavity. The other end of the air inlet pipe is connected to one side of the air inlet. An air outlet pipe is installed on one side of the top of the air cavity. The connection between the air inlet pipe and the air inlet is A temperature control device is provided, and the temperature control device is located in the air inlet pipe and cuts off the air inlet pipe;

The gas outlet pipe includes a nozzle. One end of the nozzle is fixedly connected to the top of the air chamber and communicates with the inside of the air chamber. There are six nozzles in total, and the six nozzles are along the axis of the furnace body. Evenly distributed in the circumferential direction, the inside of the nozzle is divided into three pipes by partitions. The angle between the vertical line of the nozzle and the air cavity is the first pipe, the second pipe, and the second pipe from the bottom up. The third pipe, the volume ratio of the three pipes from the bottom up is 1:3:3. The other end of the first pipe is connected to the first branch pipe, and the first branch pipe is perpendicular to the vertical line of the air inlet. , the other end of the second pipe is connected to the second branch pipe, the angle between the second branch pipe and the vertical line of the air chamber is degrees, the other end of the third pipe is connected to the third branch pipe, The third branch pipe is installed along the ray of the third channel.

Preferably, the air chamber is divided into a cavity and an inner folding wall, the inner folding wall is located on the side of the cavity close to the axis of the furnace body, and the cavity is wavy.

Preferably, the temperature control device includes a piston cavity, which is located at the interface between the air inlet pipe and the air inlet, and the piston cavity blocks the flow of the air inlet pipe, and an upper channel is provided on the top of the piston cavity. The other end of the upper channel is connected to the oxidation zone in the furnace. A piston is movably installed inside the piston cavity. A first through hole is provided on the piston. The inclination angle of the first through hole is consistent with the angle of the air inlet pipe. The inclination angles are the same, a spring is installed at the bottom of the piston, and the other end of the spring is fixedly installed at the bottom of the piston cavity. The piston cavity is located inside the air intake pipe and has a second through hole. The second through hole is The hole has the same inclination angle as the first through hole, and a phase change material is placed above the piston. The phase change material is in a solid state below 1000 degrees Celsius and in a gaseous state above 1000 degrees Celsius.

Preferably, the diameter of the air inlet pipe is smaller than the diameter of the air inlet.

The invention has the following beneficial effects:

1. The present invention sets an air chamber and an air inlet pipe inside the furnace body, and uses a temperature control device on the air inlet pipe to check the temperature change of the oxidation zone. When the temperature in the oxidation zone exceeds the melting point of most ash, the piston cavity The change in the state of the internal phase change material opens the air inlet pipe, causing the gasification agent originally in the bottom oxidation zone to be divided into two parts, slowing down the occurrence of the bottom oxidation reaction, reducing the heat release in the oxidation zone, and at the same time using the low-temperature gasification agent to The outside of the oxidation zone absorbs heat to reduce the temperature of the oxidation zone, avoid reducing ash adhesion, and reduce the probability of coking at the furnace bottom.

2. The present invention sets an air outlet pipe at the top of the air chamber and divides the air outlet pipe into three branch pipes with different inclination angles, so that the air flow in the branch pipes forms three air flow layers: high, middle and low, which are the middle and upper layers of pulverized coal. And the air flow provides continuous upward wind energy, which also compensates the temperature of the middle and upper parts of the furnace, provides oxidants for the small particles of semi-coke in the middle and upper parts, accelerates the oxidation reaction of small particles of semi-coke, reduces the carbon content of small particles of semi-coke, and reduces coal At the same time, the lower air flow layer slows down the rising speed of coal powder and gas, increases the residence time of coal powder in the oxidation zone, and improves the oxidation reaction efficiency.

Description of drawings

Figure 1 is a schematic structural diagram of the present invention;

Figure 2 is a schematic structural diagram of position A in Figure 1 of the present invention;

Figure 3 is a schematic structural diagram of position B in Figure 1 of the present invention.

In the picture: 1. Furnace body; 2. Air inlet; 3. Air cavity; 31. Cavity; 32. Inner folding wall; 4. Air inlet pipe; 5. Air outlet pipe; 51. Pipe mouth; 52. First branch pipe ; 53. Second branch pipe; 54. Third branch pipe; 6. Temperature control device; 61. Piston chamber; 62. Upper channel; 63. Piston; 64. First through hole; 65. Spring; 66. Second through hole .

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

Please refer to Figure 1-3. A fluidized bed gasifier includes a furnace body 1 and an air inlet 2. The air inlet 2 is located at the bottom of the furnace body 1. A gas chamber 3 is provided on the side wall of the bottom of the furnace body 1. The cavity 3 is divided into a cavity 31 and an inner folding wall 32. The inner folding wall 32 is located on the side of the cavity 31 close to the axis of the furnace body 1. The cavity 31 is wavy, which increases the distance between the gas inside the cavity 31 and the inside of the furnace body. The heat exchange efficiency of pulverized coal and gas increases the contact time between pulverized coal and the bottom. When the semi-coke hits the wavy inner folding wall 32, the pulverized coal will rebound to the lower part, increasing the contact time between the pulverized coal and the gasification agent. During the contact time, the bottom of the air chamber 3 is provided with an air inlet pipe 4. The other end of the air inlet pipe 4 is connected to one side of the air inlet 2. An air outlet pipe 5 is installed on one side of the top of the air cavity 3. The air inlet pipe 4 is connected to A temperature control device 6 is provided at the connection point of the air inlet 2. The temperature control device 6 is located in the air inlet pipe 4 and cuts off the air inlet pipe 4.

Among them, the gas outlet pipe 5 includes a nozzle 51. One end of the nozzle 51 is fixedly connected to the top of the air chamber 3 and connected to the inside of the air chamber 3. There are six nozzles 51 in total, and the six nozzles 51 are along the furnace body 1. The axis of the pipe is evenly distributed in the circumferential direction, and the interior of the nozzle 51 is divided into three pipes by a partition. The angle between the nozzle 51 and the vertical line of the air chamber 3 is 45 degrees. From the bottom up, there are the first pipe and the third pipe. The volume ratio of the second pipe and the third pipe from the bottom up is 1:3:3. The other end of the first pipe is connected to the first branch pipe 52. The first branch pipe 52 is perpendicular to the vertical line of the air inlet 2. , the other end of the second pipe is connected to the second branch pipe 53, the angle between the second branch pipe 53 and the vertical line of the air chamber 3 is 60 degrees, the other end of the third pipe is connected to the third branch pipe 54, The three-section pipe 54 is installed along the ray of the third channel. Due to the existence of the third branch pipe 54, the second branch pipe 53 and the first branch pipe 52, the three pipes respectively form three intersection points on the axis of the furnace body, of which six One branch pipe 52 will form a low-level air flow at the bottom layer. The low-level laminar flow is perpendicular to the axis of the furnace body 1. The low-level air flow collides and intersects at point M. Half of the air flow flows upward and half flows downward. A second branch pipe 53 will be formed in the middle layer. There is an upward trend between the middle airflow and the axis line, and there is an intersection point P on the axis line. The middle airflow hits at point P. Most of the airflow flows upward, and a small amount of airflow flows downward. The third branch pipe 54 will form a high-level airflow in the upper part. People with high-level airflow have a greater tendency to tilt upward, and most of the airflow is upward, and a very small amount of airflow is downward. The downward airflow in the upper level is driven upward by the upward airflow in the middle level, and the downward airflow in the middle level is in the lower level. Driven by the upward airflow, it moves upward. The downward airflow in the lower layer will create resistance to the oxygen-rich oxidizing agent at the bottom of the furnace and the upward airflow of pulverized coal, causing the residence time of the pulverized coal in the oxidation zone and the lower airflow to increase, allowing the large particles of semi-coke to react. As time increases, the degree of reflection intensifies. At the same time, due to the non-acceleration zone between the low-level air flow and the middle-level air flow, the reaction time of the pulverized coal and the gasifying agent will also increase. Due to the existence of air flow resistance, in order to avoid the air flow in the middle and upper layers of the furnace body, the reaction time will increase. Insufficient, affecting the circulation, at this time, the air flow of the second branch pipe 53 and the third branch pipe 54 is used to provide wind energy for the upward movement of the pulverized coal and the air flow.

Among them, the temperature control device 6 includes a piston cavity 61. The piston cavity 61 is located at the interface of the air inlet pipe 4 and the air inlet 2, and the piston cavity 61 blocks the flow of the air inlet pipe 4. The top of the piston cavity 61 is provided with an upper channel. 62. The other end of the upper channel 62 is connected to the oxidation zone in the furnace. A piston 63 is movably installed inside the piston chamber 61. A first through hole 64 is provided on the piston 63. The inclination angle of the first through hole 64 is consistent with the inlet pipe 4. The inclination angle is the same, which facilitates the airflow from the air inlet 2 to the air inlet duct 4, and avoids the restriction of the shape to form airflow resistance, resulting in a slowdown of the airflow speed. A spring 65 is installed at the bottom of the piston 63, and the other end of the spring 65 is fixedly installed. At the bottom of the piston chamber 61, the piston chamber 61 is located inside the air intake pipe 4 and has a second through hole 66. The second through hole 66 has the same inclination angle as the first through hole 64. A phase change material is placed above the piston 63. , the phase change material is in a solid state below 1000 degrees Celsius, and in a gaseous state above 1000 degrees Celsius. In order to ensure heat transfer and avoid the inconvenience of heating the phase change material, and the gaseous phase change material entering the furnace, the outlet end of the upper channel 62 can be sealed. At the same time, a high-temperature resistant thermal conductive layer is provided inside the upper channel 62, and the other end of the thermal conductive layer is connected to the furnace. Therefore, when the temperature of the oxidation zone in the furnace does not reach below 1000 degrees Celsius, the phase change material is solid. At this time, the gravity of the phase change material acts on on the piston 63, causing the piston 63 to move down and compress the spring. At this time, the first through hole 64 and the second through hole 66 are not connected, the air inlet pipe 4 is not connected, and the air flow can only enter the furnace from the air inlet 2. At 1000 degrees Celsius, the furnace has a normal reaction temperature, and the probability of coking is low. When the temperature exceeds 1000 degrees Celsius, it exceeds the melting point temperature of most of the ash inside, causing the ash to melt, bond, and coke. Therefore, when the temperature inside exceeds 1000 degrees, at this time The phase change material is affected by temperature and changes from solid to gas. The gravity of the piston 63 disappears. The piston 63 moves upward under the elastic force of the spring 65 until it perfectly fits between the second through hole 66 and the first through hole 64. The temperature control device 6 cannot Block the air inlet pipe 4, and the air flow forms two paths. The gasification agent is sprayed at the bottom and middle and upper parts of the furnace body 1 through the air inlet 2 and the air inlet pipe 4 respectively. When the temperature of the oxidation zone exceeds the limit temperature, the temperature at this time The control device 6 is opened to form two air flow paths, which reduce the molecular weight of the gasifying agent in the oxidation zone, slow down the occurrence of the oxidation reaction, reduce the heat release of the oxidizing gas, and slow down the temperature rise. At the same time, the air inlet pipe 4 is used to transfer the lower temperature The gasifying agent is guided into the gas chamber 3, and through the temperature exchange in the oxidation zone, the temperature of the oxidation zone is lowered, reducing ash melting. At the same time, the oxygen in the gas chamber 3 is preheated, so that the gasifying agent with a certain temperature is mixed in the furnace. The upper layer causes the oxidation reaction of the small particle semi-coke to increase the reaction degree of the small particle semi-coke and reduce the carbon content inside the small particle semi-coke. At the same time, because the temperature in the middle and upper layers of the furnace is low, the gasification agent also has the function of supplementing the temperature. The reaction of small-particle semi-coke is complete, the content of small-particle semi-coke is reduced, and the waste of pulverized coal caused by small-particle semi-coke being taken away by the combustible gas furnace body is avoided.

Among them, the diameter of the air inlet pipe 4 is smaller than the diameter of the air inlet 2. The diameter ratio of the air inlet pipe 4 to the air inlet 2 can be experimentally found according to the specific situation, so that the overall gas production efficiency is the highest, and the It will affect the occurrence of oxidation reaction in the oxidation zone.

The usage method of the present invention is as follows:

During normal use, the oxygen-rich oxidizing agent enters the bottom air distributor from the air inlet 2. The gasifying agent reacts with the pulverized coal in the oxidation zone under the action of the air distributor to generate combustible gas, semi-coke and high temperature. When the temperature of the oxidation zone Normally, the gravity of the phase change material acts on the piston 63 at this time, so that the second through hole 66 and the first through hole 64 are not connected, and the air inlet pipe 4 is blocked. When the temperature of the oxidation zone rises, the phase change material changes from a solid state to a solid state. When it changes to gaseous state, the weight of the gaseous phase change material is greatly reduced. At this time, the piston 63 moves upward under the elastic force of the spring 65, and the second through hole 66 and the first through hole 64 are opened. At this time, a part of the air flow enters the air inlet 2 of the cylinder. In the air distributor, another part passes through the air inlet pipe 4 to the air chamber 3. The gasification agent in the air chamber 3 exchanges heat with the gas in the oxidation zone. The gas with a certain temperature passes through the nozzle 51 to form three layers in the middle and upper part of the gasification furnace. The air flow layer provides wind energy, oxygen-rich oxidizing agent and compensation temperature for the gas in the middle and upper furnace and the semi-coke. After the temperature in the oxidation zone becomes normal, the temperature control device 6 will be reset again and the air inlet pipe 4 will be blocked.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations are mutually exclusive. any such actual relationship or sequence exists between them. Furthermore, the terms "comprises," "comprises," or any other variations thereof are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also those not expressly listed other elements, or elements inherent to the process, method, article or equipment.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art will understand that various changes, modifications, and substitutions can be made to these embodiments without departing from the principles and spirit of the invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (3)

1. A fluidized bed gasifier, including a furnace body (1), which is characterized in that: it includes a furnace body (1) and an air inlet (2), and the air inlet (2) is located in the furnace body (1) The bottom of the furnace body (1) is provided with an air chamber (3) on the bottom side wall. The bottom of the air chamber (3) is provided with an air inlet pipe (4). The other end of the air inlet pipe (4) Connected to one side of the air inlet (2), an air outlet pipe (5) is installed on the top side of the air cavity (3), and the connection between the air inlet pipe (4) and the air inlet (2) is provided with an air outlet pipe (5). Temperature control device (6), the temperature control device (6) is located in the air inlet pipe (4) and cuts off the air inlet pipe (4); The air outlet pipe (5) includes a nozzle (51). One end of the nozzle (51) is fixedly connected to the top of the air chamber (3) and communicates with the inside of the air chamber (3). The nozzle (51) There are six in total, and the six nozzles (51) are evenly distributed along the axis of the furnace body (1) in the circumferential direction. The inside of the nozzles (51) is divided into three pipes by partitions. The angle (45) degrees between (51) and the vertical line of the air cavity (3) is the first pipe, the second pipe, and the third pipe from the bottom up. The three pipes are from the bottom up. The volume ratio is 1:3:3. The other end of the first pipe is connected to the first branch pipe (52). The first branch pipe (52) is perpendicular to the vertical line of the air inlet (2). The other end of the two pipes is connected to the second branch pipe (53). The angle between the second branch pipe (53) and the vertical line of the air chamber (3) is (60) degrees. The other end is connected to the third branch pipe (54), which is installed along the ray of the third channel; The temperature control device (6) includes a piston chamber (61), which is located at the interface between the air inlet pipe (4) and the air inlet (2), and the piston chamber (61) blocks the air inlet. For the circulation of the pipe (4), an upper channel (62) is provided on the top of the piston cavity (61). The other end of the upper channel (62) is connected to the oxidation zone in the furnace. The inside of the piston cavity (61) A piston (63) is movably installed, and a first through hole (64) is provided on the piston (63). The inclination angle of the first through hole (64) is the same as the inclination angle of the air intake pipe (4), so A spring (65) is installed at the bottom of the piston (63), and the other end of the spring (65) is fixedly installed at the bottom of the piston chamber (61), which is located inside the air intake pipe (4) A second through hole (66) is provided at the position, and the second through hole (66) has the same inclination angle as the first through hole (64). A phase change material is placed above the piston (63). Substances are in a solid state below 1000 degrees Celsius and in a gaseous state above 1000 degrees Celsius. 2. A fluidized bed gasifier according to claim 1, characterized in that: the gas chamber (3) is divided into a cavity (31) and an inner folding wall (32), and the inner folding wall (32) Located on one side of the cavity (31) close to the axis of the furnace body (1), the cavity (31) is wavy. 3. A fluidized bed gasifier according to claim 1, characterized in that: the diameter of the air inlet pipe (4) is smaller than the diameter of the air inlet (2).