A rapid start-up method for pulverized coal gasification device

Abstract

The application discloses a kind of quick start method for pulverized coal gasification device, comprising the following steps: S1, preparation stage, all system is adjusted to ignitable state;S2, ignition stage: oxygen is introduced to gasifier front, after oxygen is introduced, ignition condition is provided, and then ignition sequence control is started;S3, start stage: control gasifier boost rate, so that gasifier reaches coal injection pressure;S4, coal injection stage: after reaching initial coal injection pressure, first coal line is input, after first coal line is stabilized, other coal lines are sequentially input;S5, boost stage: after all coal lines are input, adjust pulverized coal conveying system pressure, ensure that it is synchronous with gasifier boost and pressure difference remains stable, so that synthesis gas temperature, pressure is stably promoted to working pressure;S6, gasifier completes start, the application can achieve the purpose of quick start by controlling the cooperation of each system in each stage of start, avoid the problems of long duration, high material and energy consumption, high start cost and the like in start process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pulverized coal gasification, in particular to a rapid start-up method for a pulverized coal gasification device. BACKGROUND

[0002] Pulverized coal gasification is a method of using air or oxygen and steam to spray coal powder into a gasification furnace for gasification to produce coal gas.

[0003] For the coal gasification process production device in service in the current industry, each start-up is a heavy systematic work, a large amount of preliminary preparation work is required in the initial start-up, there are many uncertainties in the start-up process, the duration is long, the material consumption and energy consumption are high, and the start-up cost is large. Therefore, it is crucial to realize rapid start-up and solve the problem of high material consumption and energy consumption during start-up. SUMMARY

[0004] The purpose of the present application is to provide a rapid start-up method for a pulverized coal gasification device to solve the problems raised in the background.

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] A rapid start-up method for a pulverized coal gasification device, the pulverized coal gasification device comprising a coal grinding system, a pulverized coal pressurized conveying system, a gasification system, and a washing system, comprising the following steps:

[0007] S1, preparation stage, adjusting all systems to a ignitable state;

[0008] S2, ignition stage: introducing oxygen in front of the gasification furnace, after the oxygen introduction is completed, starting the ignition sequence control under the conventional ignition conditions, and then increasing the flow of ignition fuel gas and plant air to improve the flame stiffness and ensure the success of the ignition;

[0009] S3, start-up stage: adjusting the fuel gas / oxygen ratio in time after the start-up fuel gas and oxygen are put in, controlling the gasification furnace pressure rise rate, and making the gasification furnace reach the coal injection pressure;

[0010] S4, coal injection stage: after the initial coal injection pressure is reached, the first coal line is put in, and then the other coal lines are put in in turn after the first coal line is stabilized, and the next coal line can be put in after each coal line is stabilized;

[0011] S5, pressure rise stage: after all the coal lines are put in, adjusting the pressure of the pulverized coal conveying system to ensure that it rises synchronously with the gasification furnace and the pressure difference remains stable, and controlling the washing water amount of the syngas washing system at each position to make the syngas temperature and pressure stable and rise to the working pressure;

[0012] S6, the gasification furnace completes the start-up.

[0013] As a further solution of the present invention: the increased flow rates of the ignition fuel gas and the factory air in S2 are increased by 5-20% compared to the flow rates of the ignition fuel gas and the factory air when the ignition fire detection initially occurs.

[0014] As a further solution of the present invention: in S2, the fuel-oxygen ratio is controlled between 4.0 and 5.4, and the oxygen flow rate is increased to more than 1700 Nm3 / h.

[0015] As a further solution of the present invention: in S2, the gasifier pressure increase rate should be controlled according to the time required to complete the oxygen line leak detection program. After the oxygen line leak detection program is completed, the gasifier reaches the coal feeding pressure, which is 0.5-1.0 MPaG, shortening the waiting time.

[0016] As a further solution of the present invention: after successful start-up, all coal lines begin to circulate pulverized coal, and during the circulation stage, the pulverized coal flow rate, speed and density are controlled at a flow rate of 10-15t / h, a speed of 5-12m / s and a density of 100-300kg / m3.

[0017] As a further solution of the present invention: During the process of putting the coal line into operation in S4, the key parameters of the pressure increasing rate, the flow rates of the coal line and oxygen line, and the temperature of the annular space are controlled, and the fluctuations of the pressure increasing rate, the flow rate of the coal line and the flow rate of the oxygen line are controlled within 8%, and the temperature of the annular space is controlled within 15%. The pressure increasing rate is controlled by the opening size of the pressure regulating valve.

[0018] As a further solution of the present invention: the pressure difference between the pulverized coal conveying system in S5 and the gasifier is maintained at 0.6-1.5 MPaG.

[0019] As a further solution of the present invention: during the pressure boosting stage, the amount of washing water in various parts of the synthesis gas washing system is timely optimized and adjusted, and the washing water amount in various parts is controlled by a washing water flow regulation control loop to ensure that the synthesis gas temperature is steadily increased and the time required for synthesis gas temperature increase is shortened. The synthesis gas pressure is 3.0-4.0MpaG and the synthesis gas temperature is 180-210℃. Then, the gas can be guided in time according to downstream demand.

[0020] Compared with the prior art, the present invention has the following beneficial effects: by controlling the coordination of various systems at various stages of the start-up, the present invention can achieve the purpose of rapid start-up, thereby avoiding problems such as a long start-up process, high material and energy consumption, and high start-up costs. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] In an embodiment of the present invention, a rapid startup method for a pulverized coal gasification device is provided. The pulverized coal gasification device includes a coal grinding system, a pulverized coal pressurized conveying system, a gasification and scrubbing system, a slag removal system, and an ash water treatment system. The core equipment of the device is a gasifier, which includes an upper reaction chamber and a lower quench chamber. The quench chamber includes a downcomer and a bubble breaking device disposed around the downcomer. The scrubbing system includes a quench chamber, a Venturi scrubber, a cyclone separator, a scrubber, and associated piping systems. Its primary function is to perform preliminary scrubbing and cooling of the syngas produced by the gasifier.

[0023] The quick start method includes the following main operations:

[0024] S1. During the preparation phase, all systems are adjusted to a state where they can be ignited. During the preparation period for the start-up of the gasifier, the instrument indications are normal, the valves are operating normally, the pulverized coal reserves have met the start-up requirements, the pulverized coal pressurized conveying system, the slag removal system and the water transport system are operating normally, the gasifier-related systems are in hot standby and have conventional oxygen introduction and ignition conditions, the high-pressure nitrogen / carbon dioxide system is at normal operating pressure, and other public works and auxiliary facilities have been put into use normally.

[0025] S2. Ignition stage: After oxygen introduction is completed, the ignition sequence control is started when the ignition conditions are met. After the ignition fire detection occurs, the ignition fuel gas and factory air flow rates are appropriately increased. The increased ignition fuel gas and factory air flow rates are 5-20% higher than the ignition fuel gas and factory air flow rates when the ignition fire detection initially occurs, so as to improve the flame rigidity and ensure a successful ignition.

[0026] S3. Startup Phase: After the start-up fuel gas and oxygen are introduced, the fuel-oxygen ratio is promptly adjusted to ensure it remains within the normal range of 4.0-5.4. The oxygen flow rate is increased to above 1700 Nm³ / h. Based on the time required for the oxygen line leak detection procedure to complete (a sequential control program used to automatically detect leaks in the oxygen pipeline), the gasifier pressure increase rate is appropriately controlled. In this embodiment, the pressure increase rate can be controlled at a constant rate or a variable rate with a gradually decreasing pressure increase rate to ensure that the gasifier reaches the coal feeding pressure of 0.5-1.0 MPaG after the oxygen line leak detection procedure is completed, thereby shortening the waiting time. Pulverized coal circulation in each coal line should also be initiated immediately after successful startup, with the pulverized coal flow rate, velocity, and density controlled to 10-15 t / h, 5-12 m / s, and 100-300 kg / m³. During the circulation phase, the pulverized coal flow rate is controlled to 10-15 t / h.

[0027] S4, Coal Feeding Stage: After reaching the initial coal feeding pressure, the first coal line is introduced. Carefully control the pressure increase rate, coal and oxygen line flow rates, and annular space temperature. Fluctuations in these parameters should be kept within 8%, and the annular space temperature within 15%. Ensure that these parameters do not fluctuate significantly. The pressure increase rate is controlled by the opening of the pressure regulating valve. This is primarily controlled by the opening of the pressure regulating valve PV0080B. Once the first coal line stabilizes, the second and third coal lines can be introduced. Maintaining these parameters is crucial for each coal line.

[0028] S5. Pressure boosting stage: After all coal lines are put into operation, the pressure of the pulverized coal conveying system must be adjusted in time to ensure that it is pressurized synchronously with the gasifier and the pressure difference remains stable. The pressure difference between the pulverized coal conveying system pressure and the gasifier pressure is controlled at 0.6-1.5MPaG to prevent fluctuations. During the pressure boosting stage, the amount of washing water in various parts of the synthesis gas washing system should be optimized and adjusted in time to ensure that the synthesis gas temperature increases steadily and shorten the time required for synthesis gas temperature increase. The synthesis gas pressure and temperature are in place. The synthesis gas pressure is 3.0-4.0MpaG, and the synthesis gas temperature is 180-210℃. Then, the gas can be guided in time according to the downstream demand. At this point,

[0029] S6. The gasifier is started up.

[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0031] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A rapid start-up method for a pulverized coal gasification device, wherein the pulverized coal gasification device comprises a coal grinding system, a pulverized coal pressurized conveying system, a gasification system, and a washing system, characterized in that: The following steps are involved: S1, preparation stage, adjust all systems to the state ready for ignition; S2, ignition stage: Introduce oxygen into the front of the gasifier. After the oxygen is introduced, the ignition sequence control is started when the normal ignition conditions are met. After the ignition flame detection occurs, the ignition fuel gas and factory air flow are increased to improve the flame rigidity and ensure a successful ignition. The increased ignition fuel gas and plant air flow rates in S2 are 5-20% higher than the flow rates of the ignition fuel gas and plant air at the initial occurrence of the ignition fire detection; S3, Start-up phase: After the fuel gas and oxygen are added, the fuel-oxygen ratio is adjusted in time, and the gasifier pressure increase rate is controlled to make the gasifier reach the coal feeding pressure; S4, coal feeding stage: After the initial coal feeding pressure is reached, the first coal line is put into operation. After the first coal line is stable, other coal lines are put into operation in sequence. The next coal line can be put into operation only after each coal line is stable. During the S4 coal line operation, the key parameters of the pressure increase rate, coal line and oxygen line flow rates, and annular space temperature are controlled to keep fluctuations within 8% and within 15% of the annular space temperature, so that no significant fluctuations occur in the parameters. The pressure increase rate is controlled by the opening of the pressure regulating valve. S5, Pressure Boosting Stage: After all coal lines are put into operation, the pressure of the pulverized coal conveying system is adjusted to ensure that it is synchronized with the gasifier pressure boost and the pressure differential remains stable. At the same time, the amount of scrubbing water in each part of the syngas scrubbing system is controlled to ensure that the syngas temperature and pressure are stably raised to the operating pressure. S6. The gasifier is started up.

2. A rapid start-up method for a pulverized coal gasification device according to claim 1, characterized in that: In S3, the fuel-oxygen ratio is controlled between 4.0 and 5.4, and the oxygen flow rate is increased to 1700 Nm 3 / h or more.

3. The rapid start-up method for a pulverized coal gasification device according to claim 1, characterized in that: In S3, the gasifier pressure increase rate should be controlled according to the time required to complete the oxygen line leak detection program. After the oxygen line leak detection program is completed, the gasifier reaches the coal feeding pressure, which is 0.5-1.0 MPaG, shortening the waiting time.

4. The rapid start-up method for a pulverized coal gasification device according to claim 1, characterized in that: After the successful start of operation, all coal lines began to circulate pulverized coal. During the circulation stage, the flow rate, speed and density of pulverized coal were controlled at a flow rate of 10-15t / h, a speed of 5-12m / s and a density of 100-300kg / m 3 .

5. The rapid start-up method for a pulverized coal gasification device according to claim 1, characterized in that: The pressure difference between the pulverized coal conveying system in S5 and the gasifier is maintained at 0.6-1.5 MPaG.

6. The rapid start-up method for a pulverized coal gasification device according to claim 1, characterized in that: During the pressurization stage, the amount of washing water in various parts of the synthesis gas washing system is timely optimized and adjusted, and the amount of washing water in various parts is controlled by the washing water flow regulation control loop to ensure that the synthesis gas temperature is steadily increased and the time required for synthesis gas temperature increase is shortened. The synthesis gas pressure is 3.0-4.0MpaG and the synthesis gas temperature is 180-210℃. Then, the gas can be guided in time according to downstream demand.