CN105087071B - A kind of air powder feeding gasifying agent rotates by force coal dust gasification method - Google Patents

Abstract

The utility model relates to a pulverized coal gasification method with strong rotation of an air-feeding powder gasification agent, which relates to a pulverized coal gasification method. The invention aims to solve the problems of uneven slag hanging on the wall surface of the existing gasification furnace and high cost of gas used for transporting pulverized coal. Device: The gasification furnace is installed in the gasification furnace body, the pulverized coal burner is installed on the upper end of the gasification furnace body and communicated with the gasification furnace body, the synthesis gas channel is sealed and plugged in the lower part of the gasification furnace body, and the slag pool is located in the gasification furnace body. At the bottom of the furnace body, the gasification agent nozzle is sealed and inserted in the upper part of the gasification furnace along the tangential direction, and the pulverized coal burner is provided with an annular pulverized coal channel, and the swirl blade is installed at the near fire end of the pulverized coal channel; method : Step 1: Setting the parameters of the gasification furnace; Step 2: The dry coal powder is carried by the air into the gasification furnace; Step 3: The coal powder forms slag; Step 4: The gasification reaction between the air flow and the slag layer occurs strongly; Step 5: Slagging. The invention is suitable for pulverized coal gasification.

Description

A method of strong rotary pulverized coal gasification with air-feeding powder gasification agent

technical field

The invention relates to a pulverized coal gasification method, in particular to a pulverized coal gasification method with strong rotation of an air-feeding powder gasification agent.

Background technique

Coal gasification technology is an efficient and clean clean coal technology. The current coal gasification technology is mainly divided into four categories: moving bed gasification, fluidized bed gasification, entrained flow gasification and molten bed gasification. Among them, entrained bed gasification technology has become the main development direction of coal gasification technology due to its advantages of high gasification intensity, large production capacity and high carbon conversion rate. Entrained bed gasification has two main features. One is the high operating temperature, about 1300-1600 ° C. The ash and slag formed in the furnace is liquid, and the slag discharge method is liquid slag discharge; "Technology to protect the furnace wall and reduce heat loss. The problems existing in the entrained bed gasification furnace are: (1) The inner wall surface of the gasification furnace is easy to burn. The burning problem of the inner wall of the gasifier causes the gasifier to stop frequently. As the production source of the chemical enterprise, once the gasifier is stopped, the entire production line will be shut down, and the shutdown of the entire production line once will cause huge economic losses to the enterprise. For example, if a coal gasification production line with a coal consumption of 1000t/d is out of service, the economic loss will be more than 40 million yuan. (2) The cost of gas for transporting pulverized coal is high.

Contents of the invention

The object of the present invention is to solve the problem of uneven slag hanging on the wall surface of the existing gasification furnace and the high cost of gas for transporting pulverized coal, and further provide a pulverized coal gasification method with strong rotation of an air-feeding pulverized gasification agent.

Technical scheme of the present invention is:

The invention provides a gasification method using an air-feeding gasification agent strong rotary pulverized coal gasification device. Furnace body, gasification furnace, synthesis gas channel, slag pool, gasification agent nozzle and swirling blades, the gasification furnace is installed in the gasification furnace body, and the pulverized coal burner is installed on the upper end of the gasification furnace body and connected with the gasification furnace The gasification furnace of the furnace body is connected, the synthesis gas channel is sealed and plugged in the lower part of the gasification furnace body, the slag pool is located at the bottom of the gasification furnace body, and the gasification agent nozzle is inserted in the upper part of the gasification furnace along the tangential direction. There is an annular pulverized coal channel in the pulverized coal burner, and the swirl blade is installed near the fire end of the pulverized coal channel. The pulverized coal is carried by the air and sent into the furnace through the pulverized coal channel. The gasification method is realized through the following steps:

Step 1: Setting the parameters of the gasification furnace;

Set the internal pressure of the gasification furnace to 0.1-4MPa, and the operating temperature of the gasification furnace to be 1250-1600°C;

Step 2: The dry coal powder is carried by the air into the gasification furnace;

Dry pulverized coal at a temperature of 25-100°C is carried by the air and sent into the gasification furnace through the pulverized coal channel on the pulverized coal burner in a swirling flow, forming a rotating downward pulverized coal-air mixed flow in the furnace top area;

Step 3: pulverized coal forms slag;

After the mixed air flow of pulverized coal and air comes into contact with the high-temperature synthesis gas sucked back from the central recirculation zone, it is ignited by it and burns at the top of the furnace to form slag;

Step 4: A strong gasification reaction occurs between the gas flow and the slag layer;

The gasification agent with a temperature of 20-400°C is sprayed tangentially into the gasification furnace through the gasification agent nozzle at a speed of 100-200m/s. Under the action, 70%-90% of the molten slag is thrown to the furnace wall surface to form a slag layer with a thickness of 5-7mm. The slag layer is uniform, and the swirling airflow continuously scours the slag layer on the furnace wall surface, and has a strong gasification reaction with it;

Step five: slag discharge;

The crude coal gas produced by gasification flows out of the gasification furnace through the synthesis gas channel, and the generated ash flows into the slag pool along the wall surface, and after cooling, it is discharged out of the gasification furnace through the slag outlet at the bottom.

Compared with the prior art, the present invention has the following effects:

One, the slag layer in the present invention is formed by centrifugal force. As shown in Figure 3, in the prior art, both the pulverized coal and the gasification agent are sprayed into the furnace from the top of the gasifier, and after the pulverized coal enters the furnace, a slag is formed at a high temperature, and the slag and the gasification agent flow together in the same direction It flows to the bottom of the furnace in a direct current. During the flow process, only a small amount of slag near the wall sticks to the wall to form a slag film due to air flow pulsation; however, in the present invention, coal powder is injected from the top of the gasifier, and coal powder enters the furnace to form slag at high temperature , the gasification agent sprayed tangentially into the furnace at a speed of 100-200m/s forms a strong swirling airflow in the furnace, and the slag and the gasification agent flow down at a high speed in the near wall area, and about 80% of the slag The centrifugal force generated by the strong rotation is continuously thrown to the wall to form a slag layer.

Two, in the present invention, the amount of slag adhered to the furnace wall is large, and the thickness of the slag layer is large. In the prior art, both the pulverized coal and the gasification agent are sprayed into the furnace from the top of the gasifier, and after the pulverized coal enters the furnace, slag is formed at high temperature, and the slag and the gasification agent flow together in the same direction and generally flow to the furnace in a straight-flow manner bottom. During the flow process, only a small amount of slag near the wall sticks to the wall to form a slag film due to airflow pulsation, and the slag far away from the wall cannot stick to the wall, so only about 10% of the slag can stick to the wall. A slag film is formed on the wall, and the slag film on the wall is thinner due to the small amount of slag adhering to the furnace wall. Generally, the thickness of the slag film is 2 to 3 mm; Spray into the furnace 3 at a speed of 100-200m/s to form a strong swirling airflow, and the centrifugal force generated is enough to throw the slag to the wall to form a slag layer. About 80% of the slag is thrown to the wall during the gasification process. A slag layer is formed on the wall surface. Due to the large amount of slag adhered to the furnace wall, the slag layer on the wall surface is relatively thick, and the thickness of the slag layer can reach 5-6mm.

3. The thickness of the slag layer on the wall surface is relatively uniform in the present invention. In the prior art, both the pulverized coal and the gasification agent are sprayed into the furnace from the top of the gasifier, and after the pulverized coal enters the furnace, slag is formed at high temperature, and the slag and the gasification agent flow together in the same direction and generally flow to the furnace in a straight-flow manner bottom. During the flow process, only a small amount of slag near the wall sticks to the wall to form a slag film due to airflow pulsation, and the slag far away from the wall cannot stick to the wall, so only about 10% of the slag can stick to the wall. The slag film is formed on the wall surface. Due to the small amount of slag adhered to the furnace wall, when the gas volume distribution along the circumferential direction of the gasifier is uneven, the slag adhesion on the wall surface along the circumferential direction is uneven, resulting in the thickness of the slag film on the wall surface in the circumferential direction. uneven. However, in the present invention, the coal powder is injected from the top of the gasifier, and after the coal powder enters the furnace, slag is formed at a high temperature, and the gasification agent injected at a tangential velocity of 100-200 m/s forms a strong rotation in the furnace. The gas flow, slag and gasification agent rotate and flow downward at a high speed near the wall. In the invention, the air velocity is high and the turbulence intensity is high, which is beneficial to the mixing of the gasification agent and the molten slag. The slag and gasification agent are mixed evenly along the circumferential direction, and then thrown to the wall under the centrifugal force generated by the strong rotation to form a slag layer, and the thickness of the slag layer on the wall is relatively uniform.

4. The present invention can more effectively protect the inner wall surface of the gasifier. The main component of the slag layer on the wall is silica. The thermal conductivity of silica is about 7.6W/mk. The thermal conductivity of commonly used refractory bricks is about 20-28W/mk. The thermal conductivity of the slag layer is much smaller than that of refractory bricks, so the thermal conductivity of the slag layer Good insulation effect. In the prior art, the slag film on the wall surface is relatively thin, and the thickness of the slag film is generally 2 to 3 mm. Moreover, the thickness of the slag film along the circumferential direction is uneven, and the problem that some inner walls are not covered by the slag film is prone to occur. The inner wall of the gasifier is exposed to high-temperature smoke. In the air environment, it is easy to overheat and be burned. The gas in the gasification furnace contains 60% to 70% carbon monoxide, and high-temperature carbon monoxide is a corrosive gas. The inner wall of the gasification furnace is exposed to a high-temperature and carbon monoxide-rich environment, which is prone to chemical corrosion. In the present invention, the slag layer on the wall surface is thick, and the thickness of the slag layer is as high as 5-6mm, which is 2-3 times that of the prior art. At the same time, the thickness of the slag layer is relatively uniform, and the inner wall of the gasifier is not exposed to the high-temperature flue gas, which can effectively protect The inner wall of the gasifier will not be burned by the high-temperature gas; and the thicker slag layer will separate the inner wall of the gasifier from the gas (containing 60% to 70% of carbon monoxide) in the gasifier, which can protect the inner wall of the gasifier from Chemical corrosion of carbon monoxide gas.

5. The oxygen consumption of the present invention is small. In the prior art, the slag hanging on the wall surface is thin and uneven, and the thickness of the slag film is generally 2 to 3 mm; in the present invention, the slag hanging on the wall surface is thick and uniform, and the thickness of the slag layer is as high as 5 to 6 mm, which is 2 to 3 times that of the prior art. The thermal conductivity of the slag layer is small and the thermal insulation is good, so the invention can reduce the heat loss of the wall surface. The reaction of carbon and oxygen to generate carbon monoxide releases heat of 112.1kJ/mol, and the reaction of carbon and oxygen to generate carbon dioxide releases heat of 395kJ/mol. Obviously, the heat release of carbon and oxygen to generate carbon dioxide is 3.52 times that of carbon monoxide. Pulverized coal gasification needs to be reacted rapidly at a relatively high temperature (1250-1600°C). Although the desired coal gasification product is carbon monoxide, in order to maintain a relatively high furnace temperature, excess oxygen must be introduced to generate carbon dioxide to increase the temperature. In the prior art, the heat loss on the wall surface is relatively large. When the equivalent ratio of oxygen atoms to carbon atoms is adjusted to 1.05-1.1 during actual operation, that is to say, 5%-10% more oxygen is introduced to generate carbon dioxide to maintain the furnace temperature. In the present invention, the slag layer is thick and the heat loss on the wall is small, and the same high temperature in the furnace can be maintained by adjusting the equivalent ratio of oxygen atoms to carbon atoms to 1.01-1.05, and the oxygen consumption is reduced by about 5% compared with the prior art. Oxygen is separated from the air, and the separation process consumes a lot of electricity. The present invention reduces the consumption of a large amount of oxygen and correspondingly saves a large amount of electric energy.

Six, the coal type of the present invention has strong applicability. If the slag gasifier wants to achieve the technical route of "resisting slag with slag" to protect the water-cooled wall, it must ensure that there is a thick slag layer on the water-cooled wall surface. In the prior art, the formation of the slag film at the water-cooled wall surface only relies on the slag adhering to the wall surface, and the amount of slag adhering to the wall surface is extremely small. Under the condition that the amount of slag adhering to the wall is very small, in order to achieve a certain thickness of slag layer, strict requirements must be placed on the viscosity-temperature characteristics of coal ash: within the range of gasification temperature, the viscosity of coal ash should not be too low Or too high. If the viscosity of coal ash is too low, the fluidity of slag will be good, and the slag film will be thin, which cannot protect the water wall; if the viscosity of coal ash is too high, the fluidity of slag will be weakened, and the flow at the slag outlet will be slow and the slag discharge will not be smooth. Strict requirements on the viscosity-temperature characteristics of coal ash mean that the applicability of existing gasifier coal types is poor, and proper coal types must be selected for normal operation. In the present invention, 80% of the molten slag is thrown to the wall, and a slag layer with a certain thickness is formed on the water-cooled wall surface. The thickness of the slag layer is not sensitive to the viscosity-temperature characteristics of coal ash, so the coal type of the present invention has strong applicability. In the period of market coal price fluctuations, the "non-critical" coal type of gasifier can provide multiple choices for production enterprises and greatly improve the profitability of enterprises.

7. Under the same volume and pressure, the residence time in the pulverized coal furnace of the present invention is long, the gasification time is long, and the gasification rate is high. (1) Under the same furnace volume and pressure, compared with the gasification furnace of the prior art, the residence time of pulverized coal in the furnace is longer and the gasification time is longer in the present invention. The running track of pulverized coal and gasification agent in the prior art is shown in Figure 3. The pulverized coal is carried by the gasification agent and flows directly from the top to the bottom of the gasifier. Since the pulverized coal particles are generally smaller than 75 microns, the airflow will not carry the pulverized coal. The capacity is extremely strong, and the residence time of the pulverized coal in the furnace is the time when the gasification agent carrying the pulverized coal flows directly from the top of the gasifier to the bottom, and the residence time is very short, about 4-6s; Under the action, about 80% of the slag is thrown to the wall to form a slag layer, and the residence time of the pulverized coal in the furnace is the time for the liquid slag to slowly flow from the top of the gasifier along the wall to the bottom. Since the gasification agent is sprayed into the furnace along the tangential direction and rotates in the furnace, the gasification agent has a weak ability to carry the liquid slag flowing downward along the wall, and the liquid slag has a high viscosity and slowly flows along the wall. Down flow, which greatly prolongs the residence time of pulverized coal in the gasifier, the residence time is about 12-16s, and the residence time of pulverized coal under the same furnace volume and pressure is 2-4 times that of the prior art. (2) The gasification reaction rate of the present invention is high. The temperature in the gasifier is high, and the gasification reaction belongs to the diffusion control zone. The diffusion control zone means that at a high temperature, the reaction rate is extremely fast, so that any gas will immediately react with the carbon element as soon as it reaches the surface of the coal char particles. And quickly exhausted. At this time, the diffusion through the boundary becomes the controlling factor, and the diffusion through the boundary layer is determined by the relative velocity of coal powder and gasification agent, so the relative velocity of coal powder and gasification agent in the gasifier determines the gasification rate. rate of the chemical reaction. In the prior art, after coal powder and gasification agent are sprayed out from the burner, about 10% of the total slag adheres to the wall to form a slag film, and the remaining slag and gasification agent flow together in the same direction. About 90% of the total amount of molten slag and gasification agent flow in the same direction at a relatively low speed, the flow speed is about 0.4-0.6m/s, and the relative speed of the two is lower, about 0.08-0.12m/s. The slag forming the slag film on the wall undergoes a gasification reaction with the gasification agent flow close to the wall, and the relative velocity of the two is similar to the flow velocity of the gasification agent flow, which is about 0.4-0.6m/s. The relative velocity is relatively low, and the gas Diffusion to the particle surface is slow, and the gasification reaction rate is low. In the present invention, due to the effect of strong swirling air flow, about 80% of the total slag forms a slag layer on the wall surface, and the remaining slag rotates and flows in the furnace with the gasification agent. The slag layer flows downward along the wall, while the gasification agent rotates at high speed to wash away the slag layer. The tangential velocity of the gasification agent flow at the gasification agent inlet is 100-200m/s. The attenuation of tangential velocity of gasification agent airflow is 50-100m/s, and the average tangential velocity of gasification agent is about 75-150m/s. The relative velocity of the slag on the wall surface and the gasification agent is close to the tangential velocity of the gasification agent, with an average of 75-150m/s, which is 900-1200 times of the prior art. The molten slag, which accounts for about 20% of the total, rotates and flows with the gasifying agent in the furnace. The average velocity of the gasifying agent is 75-150m/s. The speed of the gasifying agent is high, the turbulence intensity is high, and the gasification reaction rate is high. It can be seen that the velocity of the gasification agent in the present invention is high, the relative velocity between the pulverized coal and the gasification agent is high, and the speed at which the gas diffuses to the particle surface is high, so the gasification efficiency of the present invention is much higher than that of the prior art gasifier.

8. In the present invention, the high-temperature synthesis gas ignited by refluxing is stable. In the prior art, after the pulverized coal is sprayed into the furnace, it flows downward together with the gasification agent. During the downward flow, the pulverized coal is continuously radiated by the high-temperature synthesis gas, and the temperature gradually rises. When the temperature rises above its When ignited, it is ignited. Due to the disturbance of the flow field and the fluctuation of the temperature field in the furnace, the ignition position and ignition time of pulverized coal fluctuate accordingly, and the ignition is unstable. In the present invention, since the swirling air flow flows in the area near the wall surface, the pressure in the center of the furnace is relatively low, and the high-temperature syngas at the bottom of the furnace is entrained to flow upwards in the center of the furnace, forming a stable high-temperature central recirculation zone, and the high-temperature syngas in the high-temperature central recirculation zone is refluxed to The root of the pulverized coal burner is mixed with the pulverized coal airflow to ignite the pulverized coal, which can ensure the stable ignition of the pulverized coal.

Nine, the present invention saves investment. From advantage seven, it can be seen that the residence time of pulverized coal in the furnace and the gasification reaction rate of the present invention are much higher than those of the prior art, and the gasification intensity is high. Therefore, under the same pressure and the same gas production capacity, the gasifier equipment in the present invention is much smaller than that of the prior art, and the gasification intensity is comparable to or even better than that of the prior art. Thereby saving a lot of equipment investment.

10. The pulverized coal of the present invention is fully mixed with air, so that it catches fire early. In the prior art, there is a water-cooled jacket between the pulverized coal channel and the gasification agent channel of the pulverized coal burner. The water-cooled jacket is composed of an outer wall, a water inlet channel, an interlayer, a water outlet channel, and an outer wall. About 75mm. The pulverized coal channel and the gasification agent channel are small, with a thickness of about 10mm. The pulverized coal is transported by nitrogen or carbon dioxide, which are inert gases. The distance between the pulverized coal flow and the gasification agent flow at the outlet of the burner is 7.5 times the thickness of the pulverized coal flow, which is not conducive to the rapid separation of pulverized coal and gasification agent. Mixed, not in time for fire. In the invention filed at the same time as the present invention, in the invention of using nitrogen or carbon dioxide to transport pulverized coal, since the pulverized gas used is an inert gas, the pulverized coal needs to flow for a certain distance before it can be mixed with the oxygen in the gasification agent after being sent into the furnace. There is also the problem of not being on fire in time. In the present invention, the air is used to convey the coal powder, and the air contains 21% oxygen, and a small amount of oxygen enters the furnace together with the coal powder to provide oxygen for the initial combustion of the coal powder. Compared with the prior art, it catches fire earlier.

11. The present invention uses air to feed the powder, and the air can be used to obtain local materials, saving investment. In the prior art, nitrogen or carbon dioxide is used to transport pulverized coal, and the consumption of nitrogen or carbon dioxide is relatively large. An atmospheric pressure gasifier with a gas production capacity of 40,000Nm3/h needs about ^1500Nm3 /h of nitrogen or carbon dioxide to transport pulverized coal. Nitrogen is separated from air, and the separation process consumes a lot of electrical energy. Carbon dioxide is generally a by-product of certain chemical processes, and its source is easily restricted. In the present invention, air is used to transport coal powder, which saves a large amount of electric energy compared with nitrogen gas powder delivery. In addition, air can be used to obtain local materials, which is convenient to use and is not limited by other processes.

12. The present invention reduces oxygen consumption and saves operating costs. In the prior art, nitrogen or carbon dioxide is used to transport pulverized coal. Nitrogen is an inert gas and does not participate in the reaction; while carbon dioxide participates in the endothermic reduction reaction. In order to maintain the furnace temperature, the more carbon dioxide used for powder transport, the more oxygen needs to be added The combustion reaction is exothermic to maintain the furnace temperature. The oxygen used for gasification reaction mainly comes from the oxygen in the gasification agent. The oxygen consumption of a gasifier with a coal consumption of 1000t/d is about 750t/d. In the present invention, air is used to feed the powder, and the cost is low, and the oxygen content in the air for transporting the coal powder accounts for 10% to 40% of the total oxygen content of the gasification. When the total amount of oxygen consumed by gasification is constant, the amount of oxygen used by the gasification agent of the present invention is about 10%-40% less than that of the prior art. Oxygen is separated from the air, and the separation process consumes a lot of electricity. The present invention reduces the consumption of a large amount of oxygen and correspondingly saves a large amount of electric energy.

Description of drawings

Fig. 1 is the whole structure schematic diagram of the present invention (the downward arrow at pulverized coal burner place represents the direction that pulverized coal and air enter, and label 10 is the slag layer, and label 11 is the syngas of backflow, and label 15 is the center reflow boundary, label 16 pulverized coal air flow); Fig. 2 is a sectional view along the A-A place of Fig. 1; Fig. 3 is a schematic structural view of an existing pulverized coal gasification device.

detailed description

Specific Embodiment 1: This embodiment is described in conjunction with Fig. 1 and Fig. 2. A kind of air-feeding powder gasification agent strong rotary pulverized coal gasification device in this embodiment includes a pulverized coal burner 1, a gasification furnace body 2, a gasification Furnace 3, synthesis gas channel 5 and slag pool 6, gasification furnace 3 is installed in gasification furnace body 2, pulverized coal burner 1 is installed on the upper end of gasification furnace body 2 and connected with the gasification furnace body of gasification furnace body 2 3 connected, the synthesis gas channel 5 is sealed and plugged in the lower part of the gasification furnace body 2, and the slag pool 6 is located at the bottom of the gasification furnace body 2, and it also includes a gasification agent nozzle 7 and a swirl blade 8, and the gasification agent The nozzle 7 is sealed and inserted in the upper part of the gasification furnace 3, the pulverized coal burner 1 is provided with an annular pulverized coal channel 9, and the swirl blade 8 is installed at the near fire end of the pulverized coal channel 9, and the pulverized coal is carried by the air through the Pulverized coal channel 9 is sent in the furnace.

Specific Embodiment 2: This embodiment is described with reference to FIG. 1 and FIG. 2 . The gasification furnace 3 of this embodiment is a revolving body surrounded by water-cooled walls. Such an arrangement is convenient to be arranged in the gasification furnace body 2 and matches with the inner cavity structure of the gasification furnace body 2 . Other compositions and connections are the same as in the first embodiment.

Specific Embodiment 3: This embodiment is described with reference to FIG. 1 and FIG. 2 . The water-cooled wall of this embodiment includes a plurality of circular tubes 4 arranged vertically to form a water-cooled wall. Such arrangement facilitates cooling of the gasification furnace body 2 . Other compositions and connections are the same as those in the second embodiment.

Embodiment 4: This embodiment is described with reference to FIG. 1 and FIG. 2 . The gasification agent nozzle 7 of this embodiment is sealed and inserted in the gasification furnace 3 along the tangential direction. Such setting facilitates the formation of a strong swirling flow field in the gasifier. Other compositions and connections are the same as those in Embodiment 2 or 3.

Embodiment 5: This embodiment is described with reference to FIG. 1 and FIG. 2 . The axis of the pulverized coal burner 1 of this embodiment coincides with the axis of the gasification furnace 3 . Such setting facilitates the uniform distribution of pulverized coal airflow in all directions in the gasifier. Other compositions and connections are the same as in Embodiment 4.

Specific embodiment six: This embodiment is described in conjunction with Fig. 1 and Fig. 2, and the gasification method of the strong rotary pulverized coal gasification device using air-feeding powder gasification agent in this embodiment is realized through the following steps:

Step 1: Setting parameters of gasification furnace 3;

Set the internal pressure of the gasification furnace 3 to 0.1-4MPa, and the operating temperature of the gasification furnace 3 to be 1250-1600°C;

Step 2: The dry coal powder is carried by the air into the gasification furnace 3;

Dry pulverized coal at a temperature of 25-100°C is carried by the air in a swirling flow through the pulverized coal channel 9 on the pulverized coal burner 1 and sent into the gasification furnace 3, forming a rotating downward pulverized coal-air mixture in the furnace top area. airflow;

Step 3: pulverized coal forms slag;

After the mixed air flow of pulverized coal and air comes into contact with the high-temperature syngas entrained in the central recirculation zone, it is ignited by it, and burns at the top of the furnace 3 to form slag;

Step 4: A strong gasification reaction occurs between the gas flow and the slag layer;

The gasification agent with a temperature of 20-400°C is sprayed tangentially into the gasification furnace 3 through the gasification agent nozzle 7 at a speed of 100-200m/s. Under the action of the slag, 70%-90% of the slag is thrown to the furnace wall to form a slag layer with a thickness of 5-7mm. The slag layer is uniform, and the swirling airflow continuously scours the slag layer on the furnace wall and undergoes a strong gasification reaction with it;

Step five: slag discharge;

The crude coal gas produced by gasification flows out of the gasification furnace 3 through the syngas passage 5, and the generated ash flows into the slag pool 6 along the wall, and is discharged out of the gasification furnace through the bottom slag outlet after cooling.

Specific Embodiment 7: This embodiment is described in conjunction with Fig. 1 and Fig. 2. The temperature in step 2 of this embodiment is that the dry coal powder of 25-100°C is transported by air at a speed of 18-40m/s in the pipeline in a swirling flow. The method is to send the pulverized coal into the inside of the gasification furnace 3 through the pulverized coal channel 9 on the pulverized coal burner 1. Such setting is convenient to avoid choking and blockage of the pulverized coal pipeline, which hinders the transportation. Other compositions and connections are the same as those in Embodiment 6.

Embodiment 8: This embodiment is described with reference to FIG. 1 and FIG. 2 . The gasification agent in Step 4 of this embodiment is oxygen and water vapor. Other compositions and connections are the same as those in Embodiment 7.

Specific Embodiment Ninth: This embodiment is described with reference to FIG. 1 and FIG. 2 . In this embodiment, oxygen and water vapor are mixed at a mass ratio of 0-0.4:1 and sprayed into the gasification furnace 3 . Other compositions and connections are the same as those in Embodiment 8.

The working principle of the gasifier in this embodiment is shown in FIG. 1 . The air carries the pulverized coal and is blown into the pulverized coal channel 9 in the pulverized coal burner 1, flows through the swirl vanes 8 and then sprays into the gasification furnace 3 in rotation, and forms a rotating downward pulverized coal mixed with air at the top of the gasification furnace 3 airflow. The mixed gas flow of pulverized coal and air is mixed with the high-temperature synthesis gas sucked back from the central recirculation zone, and then ignited by it, and the pulverized coal and the oxygen in the air are combusted at the top of the gasification furnace 3 to form slag. The preheated gasification agent is sprayed tangentially into the gasification furnace 3 through the gasification agent nozzle 7 at high speed, and is restricted by the furnace wall in the gasification furnace 3 to form a strongly rotating gasification gas flow. Under the ejection of this strong rotating gasification agent flow, the remaining nitrogen in the air, the slag formed by the combustion of pulverized coal, and the entrained high-temperature synthesis gas and the gasification agent flow rotate and flow downward in the near-wall area; Due to the centrifugal force generated by the strong rotation, about 80% of the molten slag is thrown onto the wall, forming a uniform thick liquid slag layer 10 . The remaining 20% of the slag, entrained high-temperature syngas and gasification agent flow are mixed together and continue to rotate and flow downward near the wall. The slag layer slowly flows downward along the wall surface, and the strongly rotating mixed air flow continuously scours the slag layer on the wall surface. reaction. After the reaction, the slag layer on the wall surface continues to flow downward along the wall surface, enters the slag pool to cool, and is discharged from the slag outlet. The rotating downward mixed gas flow continuously undergoes gasification reaction, and becomes a high-temperature syngas flow when it reaches the bottom of the gasifier. Since the mixed gas flow rotates and flows near the furnace wall, the pressure in the center of the furnace is relatively low, and the synthesis gas at the bottom of the gasifier is entrained and flows upward in the center of the furnace, forming a stable high-temperature central recirculation zone. The high-temperature syngas entrained in the high-temperature central recirculation zone flows back to the top of the gasifier, ignites the pulverized coal gas flow injected by the pulverized coal burner 1, and then enters the near-wall zone again to rotate and move downward. Finally, the generated synthesis gas flows out of the synthesis gas channel 5 .

In this embodiment, a gasification furnace with a gas production capacity of 80,000Nm ³ /h of the present invention is expected to run for 4 years without burning of the water-cooled wall, and can ensure continuous operation for 4 years without stopping. Compared with other technologies, the economic loss is reduced by 1.6 billion. Numerical calculation and verification shows that the thickness of the slag layer on the wall surface of this gasifier is 6mm, the slag layer is thick and uniform, and the residence time in the pulverized coal furnace is 14s, which is relatively long. Compared with the existing technology, the oxygen consumption is reduced by about 10%. The average relative velocity of pulverized coal and gasification agent in the furnace is about 115m/s, the relative velocity of pulverized coal and gasification agent is high, the gas diffuses to the particle surface quickly, and the reaction rate is high.

A chemical plant adopts a gasification furnace with a gas production capacity of 80,000Nm ³ /h of general technology. The residence time of pulverized coal in the furnace is about 5s, the relative velocity of gasification agent and slag is about 0.1m/s, and the slag on the water-cooled wall surface The thickness of the film is relatively thin, about 2mm, and the thickness of the slag film is uneven. Part of the inner wall surface is exposed to the high-temperature flue gas environment, and the inner wall surface is easy to be burned. On average, the car is shut down once a year due to the inner wall surface burnt, and the total economic loss is 4000 yuan per stopover. About ten thousand yuan.

Claims (4)

1. A method for gasification of pulverized coal with strong rotation of an air-sending gasification agent, the pulverized coal gasification device with a strong rotation of an air-sending gasification agent comprising a pulverized coal burner (1), a gasification furnace body (2 ), gasification furnace (3), synthesis gas channel (5), slag pool (6), gasification agent nozzle (7) and swirl blade (8), gasification furnace (3) is installed on the gasification furnace body (2), the pulverized coal burner (1) is installed on the upper end of the gasification furnace body (2) and communicates with the gasification furnace (3) of the gasification furnace body (2), and the syngas channel (5) is sealed and inserted In the lower part of the gasification furnace body (2), the slag pool (6) is located at the bottom of the gasification furnace body (2), and the gasification agent nozzle (7) is inserted in the gasification furnace (3) along the tangential direction. In the upper part, the pulverized coal burner (1) is provided with an annular pulverized coal channel (9), and the swirl vane (8) is installed near the fire end of the pulverized coal channel (9), and the pulverized coal is carried by the air through the pulverized coal channel ( 9) into the furnace, it is characterized in that: the gasification method is realized through the following steps: Step 1: Setting the parameters of the gasification furnace (3); Setting the internal pressure of the gasification furnace (3) to 0.1-4MPa, and the operating temperature of the gasification furnace (3) to 1250-1600°C; Step 2: The dry coal powder is carried by the air into the gasification furnace (3); Dry pulverized coal at a temperature of 25-100°C is carried by the air and sent into the interior of the gasification furnace (3) through the pulverized coal channel (9) on the pulverized coal burner (1) in a swirling manner, forming a rotating direction in the furnace top area. Under the pulverized coal air mixed flow; Step 3: pulverized coal forms slag; After the mixed air flow of pulverized coal and air comes into contact with the high-temperature synthesis gas sucked back from the central recirculation zone, it is ignited by it and burns at the top of the furnace (3) to form slag; Step 4: A strong gasification reaction occurs between the gas flow and the slag layer; The gasification agent with a temperature of 20-400°C is sprayed tangentially into the gasification furnace (3) through the gasification agent nozzle (7) at a speed of 100-200m/s, and the gasification agent airflow rushes into the furnace to form a strong Rotating air flow, under the action of centrifugal force, 70%-90% of the molten slag is thrown to the furnace wall to form a slag layer with a thickness of 5-7mm. The slag layer is uniform. Strong gasification reaction; Step five: slag discharge; The crude coal gas generated by gasification flows out of the gasification furnace (3) through the syngas passage (5), and the generated ash flows into the slag pool (6) along the wall surface, and is discharged out of the gasification furnace through the bottom slag outlet after cooling. 2. A method of air powder gasification gasification agent strong rotary pulverized coal gasification according to claim 1, characterized in that: the dry coal powder at a temperature of 25-100°C in step 2 is fed from the pipeline at 18-40m/ The air transport speed of s is sent to the inside of the gasification furnace (3) through the pulverized coal channel (9) on the pulverized coal burner (1) in a swirling flow. 3. The air-feeding powder gasification agent strong rotary pulverized coal gasification method according to claim 2, characterized in that: the gasification agent in step 4 is oxygen and water vapor. 4. A method of strong rotary pulverized coal gasification with air-feeding gasification agent according to claim 3, characterized in that: oxygen and water vapor are mixed at a mass ratio of 0-0.4:1 and sprayed into the gasification furnace ( 3) inside.