Single nozzle gasifier and gasification method

Abstract

The present invention discloses a single-nozzle gasifier and a gasification method. It includes a furnace body and a nozzle located at the top of the furnace body; the furnace body includes a furnace body shell and a furnace from outside to inside, and the furnace is divided into a furnace arch section and a furnace straight section from top to bottom; the nozzle outlet extends into the furnace; the gasifier also includes a first electromagnetic coil and a second electromagnetic coil, which are wound around the furnace straight section with the central axis of the gasifier as the axis; the first electromagnetic coil and the second electromagnetic coil are used to generate two magnetic fields in the same direction; the vertical spacing between the first electromagnetic coil and the outlet of the nozzle is 0.25 to 0.5 times the diameter of the furnace straight section; the vertical spacing between the second electromagnetic coil and the outlet of the nozzle is 1.5 to 2.5 times the diameter of the furnace straight section. The single-nozzle gasifier overcomes the defect that solid materials such as refractory bricks cannot constrain gasification flames at high temperatures, thereby improving the reaction intensity per unit volume of the high-temperature flame area; and improving the carbon conversion rate.

Description

Technical Field

[0001] The invention relates to a single-nozzle gasifier and a gasification method. Background Art

[0002] As one of the core technologies of clean coal technology, coal gasification technology is the foundation for the development of coal-based chemicals, coal-based liquid fuels, advanced IGCC power generation, polygeneration systems, hydrogen production, fuel cells and other process industries. It is the common technology, key technology and leading technology of these industries, and its application fields and products are extremely wide. Entrained-flow coal gasification technology, especially high-pressure and large-capacity entrained-flow coal gasification technology, has good economic and social benefits and is the most mature and widely used clean coal utilization technology.

[0003] The entrained-bed coal gasification technology adopts a gasification temperature of 1300-1700℃ and liquid slag discharge, which makes the gasification process jump from chemical reaction control at about 900℃ (fixed bed) and chemical reaction and transfer control at about 1100℃ (fluidized bed) to transfer control. As the core equipment of the entrained-bed gasification process, the gasifier operates at high temperature and high pressure, which can improve the carbon conversion rate and avoid the production of tar and phenols. The top-mounted single nozzle structure is one of the most commonly used structures of gasifiers. Due to its simple structure, convenient operation and relatively low investment cost, it has been widely used. However, its nozzle is top-mounted, the flow field characteristics of the axial downward jet and the high-temperature flame area under the nozzle are not easy to control, and the particle residence time in the gasifier is relatively short, resulting in a relatively low carbon conversion rate of the gasifier. The gasification effect is obviously inferior when the gasifier is large-scale, thus limiting the development of this technology.

[0004] In the existing technology, high temperature flames (above 2200℃), such as the flames in gasifiers, are mostly controlled by refractory materials to confine them in a certain space. Due to the high temperature of high temperature flames, on the one hand, the requirements for refractory materials are very high; on the other hand, the refractory materials are also highly corrosive, which increases the cost of the factory and wastes manpower and material resources.

[0005] Therefore, there is an urgent need for a device and method that can increase or restrict the high temperature area in the gasifier. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the defect that solid material structures such as refractory bricks cannot constrain the gasification flame at high temperature (the outer flame temperature of the flame is greater than 2200°C), resulting in low reaction intensity per unit volume in the high-temperature flame area, and thus low gasification intensity, and to provide a single-nozzle gasification furnace and a gasification method.

[0007] The present invention solves the above technical problems through the following technical solutions:

[0008] A single-nozzle gasification furnace comprises a furnace body and a nozzle located at the top of the furnace body;

[0009] The furnace body comprises a furnace shell and a furnace from outside to inside, and the furnace is divided into a furnace arch section and a furnace straight section from top to bottom;

[0010] The outlet of the nozzle extends into the furnace;

[0011] The gasifier further comprises a first electromagnetic coil and a second electromagnetic coil which are wound around the straight section of the furnace with the central axis of the gasifier as the axis; the first electromagnetic coil and the second electromagnetic coil are used to generate two magnetic fields in the same direction;

[0012] The vertical distance between the first electromagnetic coil and the outlet of the nozzle is 0.25 to 0.5 times the diameter of the straight section of the furnace;

[0013] The vertical distance between the second electromagnetic coil and the outlet of the nozzle is 1.5 to 2.5 times the diameter of the straight section of the furnace.

[0014] In the present invention, preferably, the nozzle is identical to the central axis of the furnace body.

[0015] In the present invention, as required, the nozzle may be a conventional multi-channel nozzle in the art, for example, the nozzle may be a dual-channel nozzle, a triple-channel nozzle, a quad-channel nozzle or a quintuple-channel nozzle.

[0016] Preferably, the nozzle is a dual-channel nozzle, and the dual-channel nozzle includes a channel for conveying an oxidant and a channel for conveying a fuel. The ratio of the inner diameter of the channel for conveying an oxidant to the inner diameter of the channel for conveying a fuel can be conventional in the art, preferably 1:2 to 1:6.

[0017] The channel for conveying the oxidant may be the inner channel or the outer channel in the dual-channel nozzle. The channel for conveying the fuel may also be the inner channel or the outer channel in the dual-channel nozzle. When the inner channel and the outer channel are used to convey the fuel and the oxidant respectively, a positive diffusion flame is generally formed after ignition at the outlet of the nozzle. Among them, when the inner channel and the outer channel are used to convey the oxidant and the fuel respectively, a reverse diffusion flame is generally formed after ignition at the outlet of the nozzle.

[0018] When the double-channel nozzle forms a positive diffusion flame, the oxidant and the fuel enter the nozzle from the outer channel of the nozzle and the inner channel of the nozzle respectively, and are ejected from the outlet of the nozzle. The ejection direction is vertically downward along the axis of the nozzle, and a high-temperature flame is generated after ignition.

[0019] Preferably, a nozzle cooling water inlet and a nozzle cooling water outlet are provided at different positions of the nozzle. The cooling water in the nozzle enters the cooling water channel from the nozzle cooling water inlet, cools the nozzle, and then flows out along the nozzle cooling water outlet.

[0020] In the present invention, preferably, the outside of the nozzle is also provided with a nozzle protection jacket.

[0021] Preferably, cooling water inlets and cooling water outlets are provided at different positions of the nozzle protection jacket. The cooling water in the nozzle protection jacket enters the cooling water channel from the cooling water inlet, cools the jacket, and then flows out along the cooling water outlet.

[0022] Since there is a high temperature environment of over 1300°C inside the gasifier, the nozzle may cause its surface material to be damaged if it works at high temperature for a long time, thus affecting the normal operation of the gasifier. Therefore, the nozzle protection jacket can provide redundant water cooling protection. Even if the nozzle protection jacket is damaged in a high temperature environment, the furnace body can still be kept sealed after the cooling water circulation is shut down, thereby greatly extending the working life of the nozzle in the gasifier.

[0023] Preferably, the outlet diameter of the nozzle protection jacket is 1.2 to 1.5 times the outlet diameter of the nozzle.

[0024] The connection between the nozzle and the nozzle protection jacket can be conventional in the art, preferably realized by a wafer ball valve. The wafer ball valve can be conventional in the art.

[0025] When the nozzle and the nozzle protection jacket are connected through a clamped ball valve, the nozzle can be replaced online under high temperature conditions inside the gasifier, and the nozzle can be taken out when needed as long as the nozzle and the nozzle protection jacket are matched; the airtight valve is closed, and the new nozzle can be inserted when replacing a nozzle with a different structure. By exchanging the inner and outer channels of the nozzle to form a positive diffusion flame or a reverse diffusion flame, or replacing the double-channel nozzle with a three-channel nozzle or a multi-channel nozzle to meet different operating needs, the flexibility of the gasifier operation is improved.

[0026] In the present invention, a refractory lining is generally provided between the furnace shell and the furnace.

[0027] Preferably, the front end of the nozzle protection jacket is flush with the top inner wall of the refractory lining.

[0028] The refractory lining is used to isolate the high heat generated by the flame. Under the action of the refractory lining to constrain the flame and flow field, the magnetic field generated by the first electromagnetic coil and the second electromagnetic coil can further enhance the effect of constraining the flame. The refractory lining can be conventional in the art, such as conventional refractory bricks in the art.

[0029] Preferably, refractory wool is filled between the furnace shell and the refractory lining, and the refractory wool may be conventional in the art.

[0030] In the present invention, the furnace shell may be a steel shell.

[0031] In the present invention, the means of generating voltage by using an electromagnetic coil is known to those skilled in the art.

[0032] In the present invention, the number of turns of the first electromagnetic coil and / or the second electromagnetic coil is preferably 50 to 200 turns.

[0033] In the present invention, preferably, the first electromagnetic coil is connected to the output end of the first voltage regulator. Preferably, the second electromagnetic coil is connected to the output end of the second voltage regulator.

[0034] The voltage regulator is generally provided with a voltage regulator input terminal. The voltage regulator can convert external alternating current into direct current, and output it to the positive output terminal and the negative output terminal of the voltage regulator after voltage regulation.

[0035] More preferably, the output terminal voltage of the first voltage regulator is equal to the output terminal voltage of the second voltage regulator.

[0036] The present invention also provides a gasification method for a single-nozzle gasifier, wherein the gasification method uses the gasifier as described above, forms a flame with an outer flame temperature of more than 2200° C. at the outlet of the nozzle, and performs gasification.

[0037] In the present invention, when the nozzle is a dual-channel one, the oxygen-to-carbon ratio in the oxidant and the fuel is preferably 0.6 to 1.5.

[0038] In the present invention, the intensity of the gasification reaction during the gasification is achieved by adjusting the intensity of the magnetic field between the first electromagnetic coil and the second electromagnetic coil.

[0039] The magnetic field strength is generally adjusted by the output voltage of the voltage regulator. The greater the output voltage of the voltage regulator, the greater the magnetic field strength, the more significant the flame restraint effect, and thus the greater the gasification reaction during gasification, and the higher the carbon conversion rate; conversely, the lower the carbon conversion rate.

[0040] That is, the voltage regulator can change the magnetic field strength formed by the first electromagnetic coil and the second electromagnetic coil, thereby changing the magnetic field strength distribution of the magnetic mirror and producing different effects of improving the carbon conversion rate of the gasifier. However, the effect of improving the carbon conversion rate has a limit, that is, when the plasma in the high-temperature flame moves to the second electromagnetic coil, its movement speed exceeds the limit speed that the magnetic mirror can constrain the plasma, and plasma escape will occur. The carbon conversion rate under this condition is the maximum carbon conversion rate that the gasifier can achieve. The maximum carbon conversion rate has an extreme value of 99%.

[0041] The gasification method is mainly realized by the magnetic mirror principle: two sets of electromagnetic coils are used to generate two sets of magnetic fields under the action of electromagnetic induction, wherein the direction of the magnetic field generated by the first electromagnetic coil is consistent with the direction of the magnetic field generated by the second electromagnetic coil, and together form a magnetic field structure with strong ends and weak middle - a magnetic mirror; a considerable amount of plasma is generated in the high-temperature flame formed by the nozzle during the gasification process, and the plasma enters the magnetic mirror formed by the magnetic field when passing through the inner ring of the first electromagnetic coil. The plasma is constrained by the magnetic field in the magnetic mirror and shuttles in the space formed by the two sets of electromagnetic coils and the furnace, thereby shortening the axial length of the high-temperature zone of the flame and increasing the reaction intensity per unit volume of the high-temperature flame area, thereby achieving the purpose of improving the carbon conversion rate.

[0042] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0043] The reagents and raw materials used in the present invention are commercially available.

[0044] The positive and progressive effects of the present invention are:

[0045] 1) The single-nozzle gasifier overcomes the defect that solid materials such as refractory bricks cannot constrain the gasification flame at high temperatures, thereby increasing the reaction intensity per unit volume in the high-temperature flame area and improving the carbon conversion rate.

[0046] 2) Compared with the case where only refractory bricks are used, the carbon conversion rate obtained by using magnetic field to enhance the gasification intensity can be increased by 0.5 to 2%.

[0047] 3) The high carbon conversion rate single nozzle gasifier greatly improves the practicality and flexibility of the present invention.

[0048] 4) By using the high carbon conversion rate single nozzle gasifier of the present invention, a high carbon conversion rate can be obtained without increasing the pressure inside the gasifier, so that the nozzle and the nozzle protection jacket can be connected by a wafer ball valve with weaker pressure resistance but convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a schematic structural diagram of a single-nozzle gasifier with high carbon conversion rate according to the present invention.

[0050] Explanation of the accompanying drawings: 1-furnace body shell, 2-refractory lining, 3-nozzle protection jacket, 4-cooling water inlet, 5-cooling water outlet, 6-nozzle, 7-nozzle cooling water inlet, 8-nozzle cooling water outlet, 9-nozzle feed outer channel, 10-nozzle feed inner channel, 11-first voltage regulator, 12-first electromagnetic coil, 13-second voltage regulator, 14-second electromagnetic coil, 15-direction of magnetic field generated by the first electromagnetic coil, 16-direction of magnetic field generated by the second electromagnetic coil, furnace 17, furnace arch section 18, furnace straight section 19. DETAILED DESCRIPTION

[0051] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0052] Example 1 Single nozzle gasifier

[0053] like Figure 1 The figure shows an embodiment of a high carbon conversion rate single nozzle gasifier of the present invention.

[0054] The gasifier comprises a furnace body and a nozzle located at the top of the furnace body and coaxial with the furnace body; the furnace body comprises a furnace shell 1, a refractory lining 2 and a furnace 17 from outside to inside; the furnace 17 is divided into a furnace arch section 18 and a furnace straight section 19 from top to bottom.

[0055] The nozzle structure includes a nozzle protection jacket 3 and a nozzle 6. The nozzle protection jacket 3 is provided with a cooling water inlet 4 and a cooling water outlet 5. The nozzle 6 is provided with a nozzle cooling water inlet 7, a nozzle cooling water outlet 8, an outer channel 9 and an inner channel 10. The nozzle protection jacket 3 and the nozzle 6 are connected by a sandwich ball valve. Through the sandwich ball valve, after closing the airtight valve, the nozzle matched with the nozzle protection jacket 3 can be replaced, and the inner and outer channels of the nozzle can be exchanged to form a positive diffusion flame or a reverse diffusion flame, or the double-channel nozzle can be replaced with a three-channel nozzle or a multi-channel nozzle to meet different operation needs, thereby improving the flexibility of the gasifier operation.

[0056] The first electromagnetic coil 12 is connected to the first voltage regulator 11, and the second electromagnetic coil 14 is connected to the second voltage regulator 13. The gasifier operates at normal pressure, and the gasification temperature is 1350°C.

[0057] The furnace shell 1 is a stainless steel shell with an inner diameter of 800mm and a thickness of 8mm. The inner layer is a corundum refractory lining 2 with an inner diameter of 300mm and a thickness of 80mm. A ceramic fiber insulation blanket is filled between the furnace shell 1 and the refractory lining 2. The nozzle protection jacket 3 with a water cooling channel extends into the furnace shell 1. The insertion section has a diameter of 120mm and a length of 600mm. The front end of the nozzle protection jacket 3 is basically flush with the inner surface of the top of the arch of the refractory lining 2. A small hole with a diameter of 5mm is opened at the front end. The cooling water of the nozzle protection jacket 3 enters from the cooling water inlet 4, and flows out along the cooling water outlet 5 after cooling the jacket. The inlet and outlet temperature difference of the cooling water under the normal working state of the gasifier is 5°C. Therefore, the nozzle protection jacket 3 can provide redundant water cooling protection. Even if the nozzle protection jacket 3 is damaged in a high temperature environment, it can still keep the furnace body sealed after closing its cooling water circulation, greatly extending the working life of the nozzle 6 in the gasifier. The nozzle protection jacket 3 and the nozzle 6 are both made of high temperature resistant materials.

[0058] The oxidant and the fuel enter the nozzle from the outer channel 9 and the inner channel 10 of the nozzle respectively and are ejected from the small hole at the front end of the nozzle protection jacket 3 at the front end of the nozzle. The ejection direction is perpendicular to the axis toward the furnace 17. The inner diameter ratio of the outer channel 9 and the inner channel 10 of the nozzle is 1:4. After ignition, a high-temperature flame is generated. In this embodiment, the material of the outer channel 9 of the nozzle is oxygen, and the material of the inner channel 10 of the nozzle is a water-coal slurry with a concentration of 60%. The oxygen flow rate is adjusted by a mass flow meter, and the water-coal slurry flow rate is adjusted by a calibrated screw pump. After the two streams of material enter the gasifier, they are ignited and form a flame. The maximum temperature at the center of the flame can reach above 2300°C, and a considerable amount of plasma is formed.

[0059] like Figure 1 As shown, the vertical distance between the first electromagnetic coil 12 and the outlet of the nozzle 6 is 0.25 times the inner diameter of the furnace straight section 19, and the vertical distance between the second electromagnetic coil 14 and the outlet of the nozzle 6 is 2 times the inner diameter of the furnace straight section 19. The two electromagnetic coils are powered by the first voltage regulator 11 and the second voltage regulator 13 respectively and generate two sets of corresponding magnetic fields under the action of electromagnetic induction. The inputs of the first voltage regulator 11 and the second voltage regulator 13 are both 380V AC.

[0060] Example 2 Gasification method of single nozzle gasifier

[0061] The gasification method of the high carbon conversion rate single-nozzle gasifier in this embodiment adopts the gasifier device in Example 1, and the gasification method is mainly implemented through the magnetic mirror principle: the two electromagnetic coils are powered by the first voltage regulator 11 and the second voltage regulator 13 respectively, and generate two sets of corresponding magnetic fields under the action of electromagnetic induction, and the inputs of the first voltage regulator 11 and the second voltage regulator 13 are both 380V alternating current; the magnetic field direction 15 generated by the first electromagnetic coil 12 and the magnetic field direction 16 generated by the second electromagnetic coil 14 are consistent, and together form a magnetic field structure with strong ends and weak middle - a magnetic mirror.

[0062] In this example, in this embodiment, the outer diameter of the double-channel nozzle 6 extending into the gasifier is 45 mm, and the O / C ratio of the oxygen input from the outer channel to the fuel input from the inner channel is 0.95. The magnetic field direction generated by the two sets of electromagnetic coils is from N pole to S pole from top to bottom, and the magnetic induction intensity is the largest near the center of the ring, which is about 0.08Wb / m 2 ; The magnetic flux density is the smallest at the midpoint of the center connecting line of the two sets of electromagnetic coils, and the magnetic induction intensity can be adjusted by adjusting the output voltage of the first voltage regulator 11 and the second voltage regulator 13. The nozzle 6 generates a considerable amount of plasma in the high-temperature flame formed during the gasification process, which enters the magnetic mirror formed by the magnetic field when passing through the inner ring of the first electromagnetic coil 12. The plasma is constrained by the magnetic field in the magnetic mirror and shuttles through the space formed by the first electromagnetic coil 12, the second electromagnetic coil 14 and the refractory lining 2, thereby reducing the axial length of the high-temperature zone of the flame and increasing the reaction intensity per unit volume of the high-temperature flame area, thereby achieving the purpose of improving the carbon conversion rate.

[0063] In this embodiment, by determining the composition of the inlet coal and measuring the components of the outlet synthesis gas, theoretical calculations show that the carbon conversion rate of the gasifier enhanced by electromagnetic field constraint is increased by 1.5% compared with the case without electromagnetic field constraint.

[0064] During normal operation of the gasifier, the three-channel nozzle with the same outer diameter can be replaced according to experimental needs. The inner channel of the three-channel nozzle transports 20% of the total oxygen, the middle channel transports 60% concentration of water-coal slurry, and the outer channel transports 80% of the total oxygen. After replacement, the gasifier does not need to be stopped. After the three-channel nozzle ejects the material in the furnace, it can be directly ignited at the high temperature in the furnace and the carbon conversion rate can be improved.

[0065] The present invention is not limited to the above-mentioned embodiments. Any changes in shape or structure are within the protection scope of the present invention.

Claims

1. A single nozzle gasifier, characterized in that: It includes a furnace body and a nozzle located at the top of the furnace body; The furnace body comprises a furnace shell and a furnace from outside to inside, and the furnace is divided into a furnace arch section and a furnace straight section from top to bottom; The outlet of the nozzle extends into the furnace; The gasifier further comprises a first electromagnetic coil and a second electromagnetic coil which are wound around the straight section of the furnace with the central axis of the gasifier as the axis; the first electromagnetic coil and the second electromagnetic coil are used to generate two magnetic fields in the same direction; The vertical distance between the first electromagnetic coil and the outlet of the nozzle is 0.25 to 0.5 times the diameter of the straight section of the furnace; The vertical distance between the second electromagnetic coil and the outlet of the nozzle is 1.5 to 2.5 times the diameter of the straight section of the furnace.

2. The single nozzle gasifier according to claim 1, characterized in that: The nozzle is aligned with the central axis of the furnace body; And / or, nozzle cooling water inlets and nozzle cooling water outlets are also provided at different positions of the nozzle; And / or, the nozzle is a two-channel nozzle, a three-channel nozzle, a four-channel nozzle or a five-channel nozzle.

3. The single nozzle gasifier according to claim 2, characterized in that: The nozzle is a dual-channel nozzle, which includes a channel for conveying an oxidant and a channel for conveying a fuel.

4. The single nozzle gasifier according to claim 3, characterized in that: The ratio of the inner diameter of the channel for conveying the oxidant to the inner diameter of the channel for conveying the fuel is 1:2 to 1:

6.

5. The single nozzle gasifier according to claim 1, characterized in that: The outside of the nozzle is also covered with a nozzle protection jacket.

6. The single-nozzle gasifier according to claim 5, characterized in that: The outlet diameter of the nozzle protection jacket is 1.2 to 1.5 times the outlet diameter of the nozzle; And / or, cooling water inlets and cooling water outlets are provided at different positions of the nozzle protection jacket; And / or, the connection between the nozzle and the nozzle protection jacket is achieved by a sandwich ball valve; And / or, the outlet of the nozzle and the bottom end of the nozzle protection jacket are flush with the inner top surface of the furnace.

7. The single nozzle gasifier according to claim 5, characterized in that: A refractory lining is provided between the furnace shell and the furnace.

8. The single-nozzle gasifier according to claim 7, characterized in that: Refractory wool is filled between the furnace shell and the refractory lining.

9. The single-nozzle gasifier according to claim 1, characterized in that: The number of turns of the first electromagnetic coil and / or the second electromagnetic coil is 50 to 200 turns.

10. The single-nozzle gasifier according to claim 1, characterized in that: The first electromagnetic coil is connected to the output end of the first voltage regulator; And / or, the second electromagnetic coil is connected to an output end of a second voltage regulator.

11. A gasification method for a single-nozzle gasifier, characterized in that: The gasification method adopts the single-nozzle gasification furnace as described in any one of claims 1 to 10, and forms a flame with an outer flame temperature of more than 2200° C. at the outlet of the nozzle to perform gasification.

12. The gasification method according to claim 11, characterized in that: When the first electromagnetic coil and the second electromagnetic coil are connected to the output end of the first voltage regulator and the output end of the second voltage regulator respectively, the output end voltage of the first voltage regulator is equal to the output end voltage of the second voltage regulator.

13. The gasification method according to claim 11, characterized in that: When the nozzle is a dual-channel one, the oxygen-to-carbon ratio in the oxidant and the fuel is 0.6 to 1.5.

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