A control method based on a split type coal water slurry gasification combined nozzle

Abstract

The application discloses a control method based on a split type coal water slurry gasification combined nozzle, and belongs to the field of coal gasification equipment. The control method comprises the following steps: S1, an ignition nozzle executes ignition, and ignition results are determined based on flame signal stability; S2, a main nozzle dries a furnace in a segmented temperature rising mode, and whether to switch to coal feeding is determined through multi-point temperature detection; S3, external oxygen is kept stable, and the supply amount of coal slurry and fuel gas is regulated at a set rate to realize smooth switching; S4, coal feeding results are determined based on furnace pressure and effective gas components, and when the coal feeding fails, the coal feeding is automatically restored and returns to S2; S5, after the coal feeding succeeds, the ignition nozzle is switched to a waste gas introduction channel to realize functional reuse; and S6, the cooling state of a main water cooling jacket and a secondary water cooling jacket is monitored in the whole process, and a graded response is given. The application realizes automatic control of the whole process of ignition, furnace drying and coal feeding, and has the advantages of reliable ignition, smooth switching, automatic recovery in an abnormal situation, graded protection of cooling and the like.

Description

Technical Field

[0001] This invention relates to the field of coal gasification equipment, and in particular to a control method based on a split-type coal-water slurry gasification combined nozzle. Background Technology

[0002] Pressurized coal-water slurry gasification is one of the mainstream technologies in the coal chemical industry. Traditional gasifier ignition involves a step-by-step operation of preheating burners and process burners: first, the preheating burners are used to preheat the furnace; once the furnace temperature reaches the conditions for spontaneous combustion of the coal slurry, the preheating burners are removed and the process burners are installed before coal slurry and oxygen are introduced. This method is cumbersome, labor-intensive, and poses significant safety risks when replacing burners at high temperatures. Furthermore, the drop in furnace temperature during replacement can easily lead to ignition failure or even explosion. This step-by-step operation mode has been used in industrial practice for a long time, but it has significant efficiency and safety issues. For example, after ignition, only a single flame core forms near the burner outlet. For large furnaces, the heating capacity of a single flame core is limited, and the flame propagation distance is insufficient, easily leading to a severely uneven temperature distribution within the furnace. The area opposite the burner has a lower temperature, while the area near the burner is overheated due to direct flame impact. This uneven temperature distribution not only prolongs the furnace drying time and increases energy consumption, but more seriously, it causes uneven thermal expansion of the refractory lining material within the furnace, resulting in thermal stress concentration. Secondly, the determination of whether ignition and coal feeding are successful mainly relies on indirect signals such as gasifier pressure and furnace temperature, which are highly subjective and have low accuracy. Furthermore, when the cooling water flow rate decreases or the temperature increases, only an alarm signal is issued. If the operator does not respond in time, the burner may already be damaged at high temperatures. The heat load on the burner head varies greatly under different operating conditions (initial ignition, high-temperature furnace drying stage, and normal operation stage). The existing cooling system uses a uniform monitoring threshold, which cannot meet the protection requirements of each stage. Summary of the Invention

[0003] To address the aforementioned deficiencies, this application adopts the following technical solution: A control method based on a split-type coal-water slurry gasification combined nozzle includes a combined nozzle comprising a main nozzle and an ignition nozzle. The main nozzle is provided with a central oxygen channel, a first coal slurry / fuel gas channel, and an external oxygen channel. The ignition nozzle is provided with an igniter, an ignition oxygen channel, and a second fuel gas channel. The method further includes the following steps: S1: The ignition nozzle performs ignition, and the ignition result is determined based on the stability of the flame signal over a continuous time period. If it fails, the fuel gas and oxygen are cut off and the test is repeated. When the limiting conditions are met, the test is locked. S2: After the ignition flame stabilizes, the fuel gas in the main nozzle is ignited, and the furnace is baked in a segmented heating manner. The furnace temperature is monitored by multi-point temperature detection. The decision to switch to S3 is based on whether the average temperature reaches the preset coal feeding temperature threshold and the temperature uniformity. When the average temperature exceeds the preset safety upper limit, the temperature is automatically reduced and the ignition nozzle is withdrawn. S3: Maintain a stable external oxygen supply, regulate the coal slurry supply at the first preset rate and the fuel gas supply at the second preset rate, so that the heat load fluctuation during the switching process does not exceed the preset allowable fluctuation range, until the fuel gas is withdrawn and the coal slurry meets the standard. S4: The coal feeding result is determined based on the continuous compliance of furnace pressure and effective gas components within the preset continuous compliance time: if the compliance is met, the coal feeding is successful; if the compliance is not met and the duration exceeds the preset allowable limit, the coal feeding is determined to be unsuccessful, the coal feeding is terminated, the fuel gas heating is restored, and the process returns to S2. S5: After successful coal feeding, shut off the ignition nozzle and oxygen supply, and switch the second fuel gas channel to the exhaust gas inlet channel to achieve functional reuse. S6: Monitors the cooling medium flow rate and temperature rise of the main water cooling jacket and auxiliary water cooling jacket throughout the entire process, and responds in stages based on temperature rise: it issues an early warning when the preset alarm temperature rise value is reached, and triggers protection when the preset safe temperature rise value is reached or the cooling medium flow rate is lower than the preset minimum safe flow rate, and then stops the emergency and purges with nitrogen.

[0004] Preferably, in step S1, the continuous time period is 5-15 seconds, and the limiting condition is that the cumulative number of failures reaches 3.

[0005] Preferably, in step S2, the segmented heating method is as follows: The first heating rate is used when the average furnace temperature is below 800℃. When the average furnace temperature reaches 800℃ and is lower than the coal feeding temperature threshold, a second heating rate is adopted. The first heating rate is greater than the second heating rate. The coal feeding temperature threshold is 1050℃-1200℃.

[0006] Preferably, in step S2, the temperature uniformity is the difference between the highest and lowest temperatures among multiple temperature points, and the temperature field uniformity meets the requirement that the difference between the highest and lowest temperatures does not exceed 50℃-80℃, and the safety upper limit is 1350℃-1400℃.

[0007] Preferably, in step S3, the ratio of the first preset rate to the second preset rate is determined based on the conversion factor between the calorific value of fuel gas and the calorific value of coal slurry. The conversion factor ranges from 1.2 to 2.5, and the allowable fluctuation range is ±5%.

[0008] Preferably, in step S4, the effective gas component is the sum of the volume percentages of carbon monoxide and hydrogen, with a compliance value of 80%, the continuous compliance time is 60-180 seconds, and the allowable limit is 10-30 seconds; the rate of restoring fuel gas heating is a third preset rate, which is greater than the second preset rate.

[0009] Preferably, in step S6, the temperature rise is the difference between the outlet and inlet water temperatures of the main water cooling jacket and the auxiliary water cooling jacket; the alarm temperature rise value is 10℃-20℃, the safe temperature rise value is 30℃-40℃, the minimum safe flow rate is 2-4 tons / hour, and the safe temperature rise value is greater than the alarm temperature rise value.

[0010] Preferably, the present invention also provides a split-type coal-water slurry gasification combined nozzle for implementing the above-mentioned control method, comprising a main nozzle and an ignition nozzle, wherein: the main nozzle is composed of a nozzle flange, a central oxygen channel, a first coal slurry / fuel gas channel, an external oxygen channel, a main water cooling jacket, and flanges of each main combustion port; the ignition nozzle is composed of an igniter, an ignition oxygen channel, a second fuel gas channel, a secondary water cooling jacket, and flanges of each ignition port; the ignition nozzle and the main nozzle are separately and independently configured.

[0011] Preferably, a separate fuel gas inlet is provided on the first coal slurry / fuel gas channel, and the fuel gas inlet is directly connected to the fuel gas pipeline, so that the fuel gas supply is independent of the coal slurry supply.

[0012] Preferably, the main water cooling jacket is provided with a water jacket, which divides the main water cooling jacket into an inlet channel and an outlet channel. The end of the inlet channel is provided with a water distribution plate and a throttling port. The head of the main water cooling jacket is provided with a cooling ring cavity around the main nozzle outlet. The outlet of the cooling ring cavity is provided with a flow limiting port. A water distribution ring is also provided in the cooling ring cavity. Cooling water enters through the inlet channel, is distributed circumferentially by the water distribution plate, and is accelerated into the cooling ring cavity through the throttling port. After being evenly distributed by the water distribution ring, it exchanges heat with the head of the main nozzle. The cooled water after heat exchange flows back to the other side of the water distribution plate through the flow limiting port and flows out through the outlet channel.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention achieves automated closed-loop control of the entire process of ignition, furnace drying, and coal feeding by determining the continuous stability of the flame signal, segmented heating control, dual judgment of multi-point temperature and temperature uniformity, smooth switching of calorific value conversion relationship, and comprehensive judgment of dual conditions of furnace pressure and effective gas composition. It ensures that the heat load fluctuation during the switching process does not exceed ±5%, and avoids the risks of flameout and overheating.

[0014] This invention constructs a complete automatic recovery and graded safety system for anomalies by locking cumulative ignition failures, automatically restoring fuel gas heating and returning to the furnace drying state after coal feeding failures, and implementing graded control of cooling water temperature rise and redundant protection of low flow limits. This effectively prevents burner cooling failures and significantly improves the safety and reliability of system operation.

[0015] This invention significantly improves ignition reliability and cooling efficiency by independently setting the ignition nozzle and through the synergistic effect of the water distribution plate, throttling orifice, water distribution ring, cooling ring cavity, and flow limiting orifice inside the water cooling jacket. The ignition nozzle is not affected by the scouring of the main nozzle, and the cooling water is efficiently heat-exchanged after being throttled and accelerated and evenly distributed by the water distribution ring. This effectively prevents the cooling water from short-circuiting, reduces stress corrosion and sulfur corrosion, and extends the service life of the nozzle under harsh working conditions. Attached Figure Description

[0016] Figure 1 This is a flowchart of the control method of the present invention; Figure 2 This is a three-dimensional structural schematic diagram of the combined nozzle of the present invention; Figure 3 This is a cross-sectional view of the combined nozzle of the present invention; Figure 4 This is a schematic diagram of the main structure of the combined nozzle of the present invention; Figure 5 This is a side view of the combined nozzle structure of the present invention; Figure 6 This is a top view of the combined nozzle structure of the present invention; Figure 7 This is a bottom view of the combined nozzle structure of the present invention; Figure 8 for Figure 3 Enlarged structural diagram of section B in the middle; In the diagram: 1-Main nozzle, 1-1-Nozzle flange, 1-2-Central oxygen channel, 1-3-First coal slurry / fuel gas channel, 1-4-External oxygen channel, 1-5-Main water cooling jacket, 1-6-Main combustion pipe flange, 1-7-Fuel gas port, 2-Ignition nozzle, 2-1-Igniter, 2-2-Ignition oxygen channel, 2-3-Second fuel gas channel, 2-4-Secondary water cooling jacket, 2-5-Ignition pipe flange, 3-Flame detection assembly, 4-Water jacket, 4-1-Inlet channel, 4-2-Outlet channel, 4-3-Water distribution plate, 4-4-Flow restrictor, 4-5-Throttle port, 4-6-Water distribution ring and 4-7-Cooling ring cavity. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0019] Example 1:

[0020] See Figure 1 A control method based on a split-type coal-water slurry gasification combined nozzle includes a combined nozzle comprising a main nozzle 1 and an ignition nozzle 2. The main nozzle 1 is provided with a central oxygen channel 1-2, a first coal slurry / fuel gas channel 1-3, and an external oxygen channel 1-4. The main nozzle 1 is connected to the gasifier flange via a nozzle flange 1-1. The central oxygen channel 1-2 is located at the innermost layer of the nozzle and is used to introduce central oxygen. The first coal slurry / fuel gas channel 1-3 is located at the outer layer of the central oxygen channel 1-2. During the start-up and heating phase, fuel gas is introduced; during the coal feeding and switching phase, coal slurry and fuel gas coexist; and during normal operation, coal slurry is introduced. The external oxygen channel 1-4 is located at the outer layer of the first coal slurry / fuel gas channel 1-3 and is used to introduce external oxygen to react with the coal slurry in the furnace. A main water cooling jacket 1-5 is also included. Located on the outermost layer, used for cooling and protecting the nozzle head, the ignition nozzle 2 is equipped with an igniter 2-1, an ignition oxygen channel 2-2, and a second fuel gas channel 2-3. The ignition nozzle 2 is located next to the main nozzle 1 and is a separate, independent structure from the main nozzle 1. The igniter 2-1 is a high-energy electric spark igniter, located at the center of the head of the ignition nozzle 2. The ignition oxygen channel 2-2 and the second fuel gas channel 2-3 supply oxygen and fuel gas to the head of the ignition nozzle 2, respectively. After mixing at the head of the ignition nozzle 2, they are ignited by the igniter 2-1 to form an ignition flame. The flame detection component 3 is located next to the main nozzle 1 and is used to monitor the combustion status of the ignition flame and the main flame in real time. The flame detection component 3 and the ignition nozzle 2 can be arranged at 180° opposite each other or at 90°. The ignition nozzle 2 also includes the following steps: S1: Ignition nozzle 2 performs ignition, and the ignition result is determined based on the stability of the flame signal over a continuous time period. If it fails, the fuel gas and oxygen are cut off and the test is repeated. When the limiting conditions are met, the test is locked. S2: After the ignition flame stabilizes, the fuel gas in the main nozzle 1 is ignited, and the furnace is baked in a segmented heating manner. The furnace temperature is monitored by multi-point temperature detection. The decision to switch to S3 is based on whether the average temperature reaches the preset coal feeding temperature threshold and the temperature uniformity. When the average temperature exceeds the preset safety upper limit, the temperature is automatically reduced and the ignition nozzle 2 is shut down. S3: Maintain a stable external oxygen supply, regulate the coal slurry supply at the first preset rate and the fuel gas supply at the second preset rate, so that the heat load fluctuation during the switching process does not exceed the preset allowable fluctuation range, until the fuel gas is withdrawn and the coal slurry meets the standard. S4: The coal feeding result is determined based on the continuous compliance of furnace pressure and effective gas components within the preset continuous compliance time: if the compliance is met, the coal feeding is successful; if the compliance is not met and the duration exceeds the preset allowable limit, the coal feeding is determined to be unsuccessful, the coal feeding is terminated, the fuel gas heating is restored, and the process returns to S2. S5: After successful coal feeding, shut off the ignition function of the ignition nozzle 2 and the oxygen supply, and switch the second fuel gas channel 2-3 to the exhaust gas inlet channel to achieve functional reuse. S6: Monitors the cooling medium flow rate and temperature rise of the main water cooling jacket 1-5 and the auxiliary water cooling jacket 2-4 throughout the entire process, and responds based on temperature rise levels: when the preset alarm temperature rise value is reached, an early warning is issued; when the preset safe temperature rise value is reached or the cooling medium flow rate is lower than the preset minimum safe flow rate, protection is triggered, emergency stop is initiated, and nitrogen purging is performed.

[0021] Specifically, before starting work, confirm that all channel valves are closed, and introduce cooling water into the main water cooling jacket 1-5 and the auxiliary water cooling jacket 2-4. The cooling water flow rate is 5 to 10 tons / hour, and the inlet water temperature does not exceed 40℃.

[0022] S1: Ignition nozzle 2 initiates ignition, introducing fuel gas into the second fuel gas passage 2-3. The fuel gas composition is approximately 60% H2, 30% CO, and 10% CH4, with a calorific value of approximately 12.5 MJ / Nm³. 3 Flow control is 50 to 100 Nm 3 / h, introduce oxygen into ignition oxygen channel 2-2, with the flow rate controlled at 25 to 50 Nm³. 3 / h, igniter 2-1 is started, generating an electric spark to ignite the mixture of fuel gas and oxygen, forming an ignition flame.

[0023] The flame detection component 3 monitors the flame signal intensity in real time and outputs a current signal of 4 to 20 mA. Ignition is considered successful when the flame signal remains stable over a continuous period. If ignition fails, the system automatically cuts off the fuel gas and oxygen supply, and automatically retryes after purging. The system automatically locks and alarms when the cumulative number of ignition failures reaches a certain limit. In this embodiment, the continuous period is 10 seconds, and the limit is 3 cumulative failures.

[0024] S2: After the main nozzle 1 furnace heating process is completed and the ignition flame stabilizes, the main nozzle 1 furnace heating program is initiated. Fuel gas is introduced into the first coal slurry / fuel gas channel 1-3, with the flow rate controlled at 500 to 1000 Nm³. 3 / h. Oxygen is introduced into the external oxygen channels 1-4, and the molar ratio of oxygen flow rate to fuel gas flow rate is controlled at 0.3 to 0.5. The fuel gas and oxygen mixture ejected from the main nozzle 1 are ignited by the ignition flame in the furnace to form the main flame, and the gasifier is heated up by baking.

[0025] During the furnace heating process, a total of six thermocouples located in the gasifier dome, cylinder, and slag outlet areas collect temperature values ​​at each point in real time. The system calculates the arithmetic mean of all measuring points as the average furnace temperature and identifies the difference between the highest and lowest temperatures as the temperature uniformity.

[0026] The segmented heating method is as follows: when the average furnace temperature is below 800℃, the heating rate is controlled at 6℃ / min; when the average furnace temperature reaches 800℃ and is below the coal feeding temperature threshold, the heating rate is controlled at 4℃ / min. In this embodiment, the coal feeding temperature threshold is set to 1100℃. When the average furnace temperature reaches the coal feeding temperature threshold of 1100℃ and the temperature uniformity (the difference between the highest and lowest temperatures) does not exceed 60℃, it is allowed to switch to S3. When the average temperature exceeds the safety upper limit of 1380℃, the fuel gas and oxygen flow rate is automatically reduced to cool down. After the ignition nozzle 2 completes its ignition mission, it exits, and the second fuel gas channel 2-3 remains in standby mode.

[0027] S3: Switching between coal and fuel gas, while maintaining the oxygen supply through external oxygen channels 1-4, the oxygen flow rate is kept at 1000 to 1500 Nm³. 3 The coal slurry supply is increased at a first preset rate per hour, while the fuel gas supply is decreased at a second preset rate. The coal slurry is a 62% water-coal slurry with a calorific value of approximately 7.8 MJ / kg; the fuel gas has a calorific value of approximately 12.5 MJ / Nm³. 3 The ratio of the first preset rate to the second preset rate is determined based on the conversion factor between the calorific value of fuel gas and the calorific value of coal slurry. In this embodiment, the conversion factor is 1.67. During the switching period, the furnace heat load fluctuation is controlled within ±5%. The switching continues until the fuel gas is completely shut off and the coal slurry reaches the rated supply.

[0028] S4: Coal Feeding Result Judgment and Anomaly Handling. During the coal feeding process, the system simultaneously monitors the pressure inside the gasifier and the content of effective gas components in the syngas. The design pressure is 4.0 MPa, and the preset stable pressure range is 3.6 MPa to 4.4 MPa. The effective gas component is the sum of the volume percentages of carbon monoxide and hydrogen, measured in real time by an online infrared analyzer, with a target value of 80%. The coal feeding result is determined based on the furnace pressure and the continuous compliance of the effective gas components in the syngas within a preset continuous compliance time: if the target is met, the coal feeding is confirmed as successful; if the target is not met and the duration exceeds the preset allowable limit, the coal feeding is determined to be a failure, the coal slurry is automatically cut off, and fuel gas heating is restored at a third preset rate, returning to S2 for reheating the furnace. In this embodiment, the continuous compliance time is 120 seconds, the allowable limit is 20 seconds, and the third preset rate is greater than the second preset rate.

[0029] S5: Normal operation and ignition nozzle function conversion. After successful coal feeding, the ignition function of ignition nozzle 2 and the supply of ignition oxygen channel 2-2 are turned off. The second fuel gas channel 2-3 is switched to the exhaust gas inlet channel and the flash vapor discharged from the gasifier flash tank is introduced into it. It mainly contains H2 and CO and is treated for co-combustion, so as to realize the function reuse of ignition nozzle 2 in the normal operation stage.

[0030] S6: Full-process cooling water safety interlock, monitoring the cooling medium flow rate and temperature rise of the main water cooling jacket 1-5 and the auxiliary water cooling jacket 2-4 throughout the process, with a graded response based on temperature rise. The temperature rise is the difference between the outlet and inlet water temperatures of the main water cooling jacket 1-5 and the auxiliary water cooling jacket 2-4.

[0031] An alarm is triggered when the alarm temperature rise value is reached. An emergency stop is executed and nitrogen purging protection is activated when the safe temperature rise value is reached or the cooling medium flow rate is lower than the minimum safe flow rate.

[0032] In this embodiment, the inlet water temperature is 32℃, the alarm temperature rise is 15℃, the safe temperature rise is 35℃, and the minimum safe flow rate is 3 tons / hour. The nitrogen flow rate is 200 to 500 Nm³. 3 / h, continue purging for 5 to 10 minutes.

[0033] In some preferred embodiments, in step S1, the continuous time period is 5-15 seconds, and the limiting condition is that the cumulative number of failures reaches 3. The continuous time period during which the flame signal remains stable is 5-15 seconds, avoiding misjudgments caused by momentary flame flickering or signal interference. Ignition is only determined to be successful when the flame signal remains stable for a sufficiently long time window, significantly improving the accuracy of ignition determination. At the same time, setting the system to lock when the cumulative number of failures reaches 3 avoids infinite loop attempts caused by system failures, improving system security. In some preferred embodiments, in step S2, the segmented heating method is as follows: The first heating rate is used when the average furnace temperature is below 800℃. When the average furnace temperature reaches 800℃ and is below the coal feeding temperature threshold, a second heating rate is adopted, where the first heating rate is greater than the second heating rate. The coal feeding temperature threshold is 1050℃-1200℃. The temperature dividing point for the segmented heating method is set at 800℃, and different heating rates are used in different temperature ranges. A faster first heating rate is used below 800℃ to shorten the furnace drying time, and a slower second heating rate is switched after reaching 800℃ to avoid excessive thermal stress on the lining material in the high-temperature range. This ensures furnace drying efficiency, effectively protects the furnace lining refractory material, and extends the service life of the gasifier.

[0034] In some preferred embodiments, in step S2, the temperature uniformity is the difference between the highest and lowest temperatures among multiple points. The temperature field uniformity meets the requirement that the difference between the highest and lowest temperatures does not exceed 50℃-80℃. The safety upper limit is 1350℃-1400℃. When the average furnace temperature exceeds this upper limit, the flow rate of fuel gas and oxygen is automatically reduced to cool down, effectively preventing the softening and erosion of the lining material caused by furnace overheating and ensuring the long-term safe operation of the gasifier.

[0035] In some preferred embodiments, in step S3, the ratio of the first preset rate to the second preset rate is determined based on a conversion factor between the calorific value of fuel gas and the calorific value of coal slurry. The conversion factor ranges from 1.2 to 2.5, and the allowable fluctuation range is ±5%. This achieves a constant calorific value transition during the switching process between fuel gas and coal slurry, effectively avoiding flameout caused by a sudden drop in heat load and overheating caused by a sudden increase in heat load.

[0036] In some preferred embodiments, in step S4, the effective gas component is the sum of the volume percentages of carbon monoxide and hydrogen, with a compliance value of 80%. The duration of compliance is 60-180 seconds, and the allowable limit is 10-30 seconds. The rate at which fuel gas heating is restored is a third preset rate, which is greater than the second preset rate. Using syngas quality as a direct criterion for successful coal feeding is more accurate and reliable than traditional methods that rely on indirect signals such as temperature and pressure. By setting the duration of compliance to 60-180 seconds, misjudgments caused by instantaneous fluctuations are avoided, thus improving the reliability of successful coal feeding determination.

[0037] In some preferred embodiments, in step S6, the temperature rise is the difference between the outlet and inlet water temperatures of the main water cooling jacket 1-5 and the auxiliary water cooling jacket 2-4; the alarm temperature rise value is 10℃-20℃, the safe temperature rise value is 30℃-40℃, the minimum safe flow rate is 2-4 tons / hour, and the safe temperature rise value is greater than the alarm temperature rise value.

[0038] Example 2:

[0039] The present invention also provides a split-type coal-water slurry gasification combined nozzle for implementing the above-mentioned control method, comprising a main nozzle and an ignition nozzle, wherein: the main nozzle 1 is composed of a nozzle flange 1-1, a central oxygen channel 1-2, a first coal slurry / fuel gas channel 2-3, an external oxygen channel 1-4, a main water cooling jacket 1-5, and various main combustion port flanges 1-6; the ignition nozzle 2 is composed of an igniter 2-1, an ignition oxygen channel 2-2, a second fuel gas channel 2-3, a secondary water cooling jacket 2-4, and various ignition port flanges 2-5; the ignition nozzle 2 and the main nozzle 1 are separately and independently configured.

[0040] In some preferred embodiments, a separate fuel gas inlet 1-7 is provided on the first coal slurry / fuel gas channel 1-3. The fuel gas inlet 1-7 is directly connected to the fuel gas pipeline, allowing the fuel gas supply to be independent of the coal slurry supply. It is connected to both the fuel gas pipeline and the sewage pipeline, with switching control achieved via a three-way switching valve. During start-up and furnace drying, the fuel gas inlet 1-7 is connected to the fuel gas pipeline, supplying fuel gas to the first coal slurry / fuel gas channel 1-3. During normal production, the fuel gas inlet 1-7 is connected to the sewage pipeline, enabling the gasifier to co-process organic wastewater. The organic wastewater, after being pressurized and atomized, is injected into the furnace through the first coal slurry / fuel gas channel 1-3, where it undergoes oxidative decomposition at high temperatures, achieving co-processing.

[0041] In some preferred embodiments, a water jacket 4 is provided inside the main water cooling jacket 1-5, dividing the main water cooling jacket 1-5 into an inlet channel 4-1 and an outlet channel 4-2. A water distribution plate 4-3 and a throttling orifice 4-5 are provided at the end of the inlet channel 4-1. A cooling ring cavity 4-7 is provided around the outlet of the main nozzle 1 at the head of the main water cooling jacket 1-5. A flow limiting orifice 4-4 is provided at the outlet of the cooling ring cavity 4-7. A water distribution ring 4-6 is also provided inside the cooling ring cavity 4-7. Water enters through the inlet channel 4-1, is distributed circumferentially by the water distribution plate 4-3, and is accelerated into the cooling ring cavity 4-7 through the throttling port 4-5. After being evenly distributed by the water distribution ring 4-6, it exchanges heat with the head of the main nozzle 1. The cooled water after heat exchange flows back to the other side of the water distribution plate 4-3 through the flow limiting port 4-4 and flows out through the outlet channel 4-2. The structure of the auxiliary water cooling jacket 2-4 is the same as that of the main water cooling jacket 1-5. It is set on the outermost side of the ignition nozzle 2 and is used to cool and protect the head of the ignition nozzle 2.

[0042] The main water cooling jacket 1-5 has a special structure, primarily designed for harsh operating conditions such as high coal ash melting point (not lower than 1350℃), high sulfur content (not lower than 3%), or low coal slurry concentration (not higher than 58%). Cooling water enters through the inlet channel 4-1, first passing through the water distribution plate 4-3 for uniform circumferential distribution, and then through the throttling orifice 4-5 for speed increase, allowing the cooling water to enter the cooling ring cavity 4-7 at a high flow rate of not less than 2 m / s. The cooling ring cavity 4-7 is arranged around the high-temperature zone of the main nozzle 1 head, and the water distribution ring 4-6 further evenly distributes the water flow throughout the entire ring cavity. After sufficient heat exchange with the head of the main nozzle 1 within the annular cavity, the cooling water returns through the flow-limiting port 4-4, passes through the water distribution plate 4-3 again, and flows out from the outlet channel 4-2. The design of the throttling port 4-5 accelerates the cooling water before it enters the cooling annular cavity 4-7, increasing the turbulence intensity and convective heat transfer coefficient within the cavity. The design of the flow-limiting port 4-4 prevents the cooling water from short-circuiting within the cavity, i.e., from flowing out from the near end without sufficient heat exchange, ensuring uniform flow of the cooling water around the circumference of the cavity. The water distribution ring 4-6 further distributes the water flow evenly throughout the entire annular cavity. This structure ensures sufficient and uniform heat exchange between the cooling water and the head of the main nozzle 1, effectively reducing the metal wall temperature of the nozzle head, minimizing stress corrosion and sulfur corrosion at high temperatures, and extending the service life of the main nozzle 1 under harsh operating conditions.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A control method based on a split-type coal-water slurry gasification combined nozzle, comprising a combined nozzle, characterized in that, The combined nozzle includes a main nozzle and an ignition nozzle. The main nozzle is provided with a central oxygen channel, a first coal slurry / fuel gas channel, and an external oxygen channel. The ignition nozzle is provided with an igniter, an ignition oxygen channel, and a second fuel gas channel. The method also includes the following steps: S1: The ignition nozzle performs ignition, and the ignition result is determined based on the stability of the flame signal over a continuous time period. If it fails, the fuel gas and oxygen are cut off and the test is repeated. When the limiting conditions are met, the test is locked. S2: After the ignition flame stabilizes, the fuel gas in the main nozzle is ignited, and the furnace is baked in a segmented heating manner. The furnace temperature is monitored by multi-point temperature detection. The decision to switch to S3 is based on whether the average temperature reaches the preset coal feeding temperature threshold and the temperature uniformity. When the average temperature exceeds the preset safety upper limit, the temperature is automatically reduced and the ignition nozzle is withdrawn. S3: Maintain a stable external oxygen supply, regulate the coal slurry supply at the first preset rate and the fuel gas supply at the second preset rate, so that the heat load fluctuation during the switching process does not exceed the preset allowable fluctuation range, until the fuel gas is withdrawn and the coal slurry meets the standard. S4: The coal feeding result is determined based on the continuous compliance of furnace pressure and effective gas components within the preset continuous compliance time: if the compliance is met, the coal feeding is successful; if the compliance is not met and the duration exceeds the preset allowable limit, the coal feeding is determined to be unsuccessful, the coal feeding is terminated, the fuel gas heating is restored, and the process returns to S2. S5: After successful coal feeding, shut off the ignition nozzle and oxygen supply, and switch the second fuel gas channel to the exhaust gas inlet channel to achieve functional reuse. S6: Monitors the cooling medium flow rate and temperature rise of the main water cooling jacket and auxiliary water cooling jacket throughout the entire process, and responds in stages based on temperature rise: it issues an early warning when the preset alarm temperature rise value is reached, and triggers protection when the preset safe temperature rise value is reached or the cooling medium flow rate is lower than the preset minimum safe flow rate, and then stops the emergency and purges with nitrogen.

2. The control method based on a split-type coal-water slurry gasification combined nozzle according to claim 1, characterized in that, In S1, the continuous time period is 5-15 seconds, and the limiting condition is that the cumulative number of failures reaches 3.

3. The control method based on a split-type coal-water slurry gasification combined nozzle according to claim 1, characterized in that, In S2, the segmented heating method is as follows: When the average furnace temperature is below 800℃, the first heating rate is used; when the average furnace temperature reaches 800℃ and is below the coal feeding temperature threshold, the second heating rate is used. The first heating rate is greater than the second heating rate. The coal feeding temperature threshold is 1050℃-1200℃.

4. The control method based on a split-type coal-water slurry gasification combined nozzle according to claim 1, characterized in that, In S2, the temperature uniformity is the difference between the highest and lowest temperatures among multiple temperature points. The temperature field uniformity meets the requirement that the difference between the highest and lowest temperatures does not exceed 50℃-80℃, and the safety upper limit is 1350℃-1400℃.

5. The control method based on a split-type coal-water slurry gasification combined nozzle according to claim 1, characterized in that, In step S3, the ratio of the first preset rate to the second preset rate is determined based on the conversion factor between the calorific value of fuel gas and the calorific value of coal slurry. The conversion factor ranges from 1.2 to 2.5, and the allowable fluctuation range is ±5%.

6. The control method based on a split-type coal-water slurry gasification combined nozzle according to claim 1, characterized in that, In step S4, the effective gas component is the sum of the volume percentages of carbon monoxide and hydrogen, with a compliance value of 80%. The duration of compliance is 60-180 seconds, and the allowable limit is 10-30 seconds. The rate at which the fuel gas heat supply is restored is a third preset rate, which is greater than the second preset rate.

7. The control method based on a split-type coal-water slurry gasification combined nozzle according to claim 1, characterized in that, In step S6, the temperature rise is the difference between the outlet and inlet water temperatures of the main water cooling jacket and the auxiliary water cooling jacket; the alarm temperature rise value is 10℃-20℃, the safe temperature rise value is 30℃-40℃, the minimum safe flow rate is 2-4 tons / hour, and the safe temperature rise value is greater than the alarm temperature rise value.

8. A split-type coal-water slurry gasification combined nozzle, used to implement the control method as described in any one of claims 1 to 7, characterized in that, It includes a main nozzle and an ignition nozzle, wherein: the main nozzle is composed of a nozzle flange, a central oxygen channel, a first coal slurry / fuel gas channel, an external oxygen channel, a main water cooling jacket, and flanges of each main combustion port; the ignition nozzle is composed of an igniter, an ignition oxygen channel, a second fuel gas channel, a secondary water cooling jacket, and flanges of each ignition port; the ignition nozzle and the main nozzle are separately and independently set.

9. The split-type coal-water slurry gasification combined nozzle according to claim 8, characterized in that, The first coal slurry / fuel gas channel is provided with a separate fuel gas port, which is directly connected to the fuel gas pipeline, so that the fuel gas supply is independent of the coal slurry supply.

10. The split-type coal-water slurry gasification combined nozzle according to claim 8, characterized in that, The main water cooling jacket is equipped with a water jacket, which divides the main water cooling jacket into an inlet channel and an outlet channel. The end of the inlet channel is equipped with a water distribution plate and a throttling port. The head of the main water cooling jacket is equipped with a cooling ring cavity around the main nozzle outlet. The outlet of the cooling ring cavity is equipped with a flow limiting port. A water distribution ring is also provided in the cooling ring cavity. Cooling water enters through the inlet channel, is distributed circumferentially by the water distribution plate, and is accelerated into the cooling ring cavity through the throttling port. After being evenly distributed by the water distribution ring, it exchanges heat with the head of the main nozzle. The cooled water after heat exchange flows back to the other side of the water distribution plate through the flow limiting port and flows out through the outlet channel.

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