JP6865149B2 - Blockage prevention device and blockage prevention method for coal gasification equipment - Google Patents

Description

The present invention relates to a blockage prevention device and a blockage prevention method for preventing blockage of coal gasification equipment.

If blockage occurs due to slugging due to the adhesion of scattered chars in the gasification furnace of a coal gasification facility, stable operation of not only the gasification furnace but also the entire gasification facility cannot be performed.

As a technique for preventing slugging of a gasification furnace, for example, Patent Document 1 describes a slugging prevention device in which a steam injection nozzle is provided in a reducer on the upper part of the gasification furnace. In this device, when the gasification operation is started, the valve is opened and steam is injected from the steam injection nozzle along the gasification furnace wall to prevent molten slag and char from adhering to the gasification furnace wall.

Further, in Patent Document 2, nitrogen gas is charged into the wall surface of the reducer in the upper part of the gasification furnace, and the oxygen concentration in the generated gas is adjusted to 23 to 54 vol%, whereby the outlet gas temperature of the reducer (gasification reaction end temperature). Describes a coal gasification method that controls the operation of the coal to an optimum temperature of 1000 to 1100 ° C. in terms of both promotion of chargasification in the reducer and prevention of fouling due to ash adhesion and accumulation in the heat recovery steam generator in the wake. Has been done.

On the other hand, in Non-Patent Document 1, since fine carbon (C) particles in char act as a dispersant, carbon in char is required to suppress sintering of partially melted slag particles. It is described that if the carbon concentration in the char is equal to or higher than a predetermined concentration (wt%), sintering of slag particles can be prevented.

Japanese Unexamined Patent Publication No. 6-313537 Japanese Unexamined Patent Publication No. 7-41776 Akio Ueda, 1 outside, "Sintering characteristics of scattered slag powder in airflow layer coal gasifier", Proceedings of the Japan Society of Mechanical Engineers (B), Vol. 63, No. 609 (1997-5), Paper No. 96-1063, p. 303-309

In order to improve the efficiency of operation in the apparatus described in Patent Document 1, it is preferable that the steam from the steam injection nozzle is not always continuously injected during the gasification operation, but the steam is intermittently injected. Setting a long time for stopping the injection (injection stop time) contributes to the efficiency of operation.

However, while the steam injection is stopped, the char is allowed to adhere to the gasification furnace wall, and the char adhering to the gasification furnace wall is gasified and the carbon concentration in the char (C concentration in the char) decreases. As described in Non-Patent Document 1, when the C concentration in the char is reduced to less than a predetermined concentration (C concentration in the char that prevents sintering of partially melted slag particles: C concentration in the char that prevents sintering), the slag particles are separated from each other. If the char that adheres to the gasification furnace wall exists for a long time and the C concentration in the char is reduced to less than the sintering prevention C concentration, the slugging prevention effect is reduced. Since the anti-sintering C concentration differs depending on the type of coal to be tested, the temperature and pressure of the gas in the gasification furnace, the concentration of various components, etc., the operation is performed while reliably preventing the sintering of slag particles. It is difficult to improve efficiency.

Further, in the method described in Patent Document 2, nitrogen gas is charged into the reducer, and the amount of gas produced in the reducer is large, so that the carbon monoxide and hydrogen concentrations are low, and as a result, the cold gas efficiency is low. There is a risk of becoming. Further, the gas temperature at the outlet of the reducer is as high as 1000 to 1100 ° C., and it is considered that the gasification reaction of the char continues to occur, and there is a possibility that the C concentration in the char necessary for preventing sintering cannot be sufficiently secured.

Therefore, an object of the present invention is to provide a blockage prevention device and a blockage prevention method for gasification equipment capable of improving the efficiency of operation while reliably preventing slugging.

In order to achieve the above object, the device according to the first aspect of the present invention is a blockage prevention device provided in a coal gasification facility including a gasification furnace, which includes a gasifier medium injection nozzle and an injection stop time calculation. A means and an injection control means are provided.

The gasification furnace is a gasification unit that converts coal into a gas containing carbon monoxide and hydrogen as the main components by putting it into the furnace together with an oxidizing agent and heating it, and also converts the ash in the coal into molten slag. It has a heat recovery unit that is arranged above the gasification unit and communicates with the gasification unit.

The gasifier medium injection nozzle can inject a predetermined medium into the heat recovery unit. The detection means detects the temperature, carbon dioxide concentration, and pressure of the gas containing carbon monoxide and hydrogen as main components flowing through the heat recovery unit.

The injection stop time calculation means sets the char of the heat recovery unit to the minimum value of the carbon concentration in the char (C concentration in the char) that prevents the molten slag from adhering to each other and sintering in the heat recovery unit. The time until the medium carbon concentration decreases is calculated as the maximum shutdown time of the gasifier medium injection nozzle using the temperature, carbon dioxide concentration, and pressure detected by the detecting means.

The injection control means intermittently injects the medium from the gasifier medium injection nozzle so that the medium injection stop does not continue beyond the maximum stop time of the gasifier medium injection nozzle calculated by the injection stop time calculation means. ..

The method according to the first aspect of the present invention is a method for preventing blockage in a coal gasification facility including a gasification furnace, which includes a detection step, an injection stop time calculation step, and an injection control step.

The gasification furnace is a gasification unit that converts coal into a gas containing carbon monoxide and hydrogen as the main components by putting it into the furnace together with an oxidizing agent and heating it, and also converts the ash in the coal into molten slag. It has a heat recovery unit that is arranged above the gasification unit and communicates with the gasification unit. The coal gas facility is provided with a gasifier medium injection nozzle capable of injecting a predetermined medium into the heat recovery unit.

In the detection step, the temperature, carbon dioxide concentration, and pressure of the gas containing carbon monoxide and hydrogen as main components flowing through the heat recovery unit are detected.

In the injection stop time calculation step, the carbon concentration in the char of the heat recovery unit decreases to the minimum value of the carbon concentration in the char that prevents the molten slag from adhering to each other and sintering in the heat recovery unit. The time until is calculated as the maximum shutdown time of the gasifier medium injection nozzle using the temperature, carbon dioxide concentration, and pressure detected in the detection step.

In the injection control step, the medium is intermittently injected from the gasifier medium injection nozzle so that the injection stop does not continue beyond the maximum stop time of the gasifier medium injection nozzle calculated in the injection stop time calculation step.

The gasifier medium injection nozzle injects the medium along the inner wall surface of the heat recovery unit, for example.

_{The maximum downtime of the gasifier medium injection nozzle is determined by using the temperature, carbon dioxide concentration (CO 2} concentration), and pressure of the gas (produced gas) containing carbon monoxide and hydrogen as the main components flowing through the heat recovery section. The reaction rate of carbon in char (C in char) is calculated, and the reaction time at which the carbon concentration in char (C concentration in char) becomes the anti-sinter carbon concentration (anti-sinter C concentration) from the obtained reaction rate. Can be obtained by calculating. Since the value of the anti-sintering C concentration differs depending on the coal type, the anti-sintering C concentration of the coal to be gasified (test coal) is set (memorized) in advance.

For intermittent injection control so that the injection stop does not continue beyond the maximum stop time, control is performed at intervals of the longest stop time, for example, to repeat injection for a predetermined time and injection stop for the longest stop time. included.

In the above configuration or method, the gasification section of the gasification furnace gasifies the combustible component in coal and converts it into a gas (produced gas) containing carbon monoxide and hydrogen as main components. The generated gas contains char, scattered ash and some molten slag. If char, scattered ash, and molten slag adhere to the inner wall surface (furnace wall surface) of the heat recovery section at the top of the gasification furnace and stay on the furnace wall surface for a long time, the char gasifies and the C concentration in the char decreases. To do. When the C concentration in the char is reduced, the ash in the char is sintered, and the molten slags are bonded to each other for slugging (ash melted by combustion adheres to the furnace wall surface to reduce heat collection and increase the pressure loss in the furnace. There is a risk of causing a phenomenon). Further, when a heat recovery boiler is provided in the wake of the heat recovery section, chars having a low C concentration in the chars adhering to the furnace wall surface of the heat recovery section are scattered and flow into the heat recovery boiler from the gasification furnace. Fowling (volatile components such as sodium in ash evaporate and adhere to the heat transfer tube by adhering to and accumulating on the heat transfer tube of the heat recovery boiler, causing inhibition of heat transfer and an increase in pressure loss. Phenomenon) may occur. If slugging or fouling occurs in the heat recovery section or heat recovery boiler at the top of the gasification furnace, the flow path may be blocked, making it difficult to operate the gasification equipment.

In order to deal with such slugging and fouling, in the above configuration and method, the char adhering to the furnace wall surface of the heat recovery part of the gasifier is within the maximum stop time due to the injection of the medium from the gasifier medium injection nozzle. It is blown periodically at intervals of 1 to ensure that it is removed from the furnace wall surface before the C concentration in the char becomes less than the anti-sintering carbon concentration (anti-sintering C concentration). That is, the C concentration in the char can be maintained (secured) at or higher than the anti-sintering C concentration, slugging can be reliably prevented, and fouling can be suppressed. Therefore, it is possible to prevent the gasification equipment from being blocked by scattered ash and char, realize stable operation of the gasification equipment, and improve reliability.

Further, since the medium is not always continuously injected from the gasification furnace medium injection nozzle during the gasification operation but intermittently, the operation efficiency can be improved.

The device according to the second aspect of the present invention is the blockage prevention device of the first aspect, and includes a boiler medium injection nozzle. The coal gasification facility is equipped with a heat recovery boiler installed in the wake of the gasification furnace. The boiler medium injection nozzle can inject a predetermined medium into the heat recovery boiler.

The detecting means detects at least the temperature of the gas containing carbon monoxide and hydrogen as main components flowing through the heat recovery boiler. The injection stop time calculation means reduces the carbon concentration in the char of the heat recovery boiler to the minimum value of the carbon concentration in the char that prevents the molten slag from adhering to each other and sintering in the heat recovery boiler. The time until is calculated as the maximum stop time of the boiler medium injection nozzle by using the temperature, the carbon dioxide concentration, and the pressure detected by the detecting means. The injection control means intermittently injects the medium from the boiler medium injection nozzle so that the injection stop of the medium does not continue beyond the maximum stop time of the boiler medium injection nozzle calculated by the injection stop time calculation means.

The method according to the second aspect of the present invention is the blockage prevention method of the first aspect, and the coal gasification equipment includes a heat recovery boiler in the wake of the gasification furnace. The coal gasification facility is provided with a boiler medium injection nozzle capable of injecting a predetermined medium inside the heat recovery boiler.

In the detection step, at least the temperature of the carbon monoxide and hydrogen-based gas flowing through the heat recovery boiler is detected. In the injection stop time calculation step, the carbon concentration in the char of the heat recovery boiler is reduced to the anti-sintering carbon concentration, which is the minimum value of the carbon concentration in the char that prevents the molten slag from adhering to each other and sintering in the heat recovery boiler. The time until is calculated as the maximum stop time of the boiler medium injection nozzle using the temperature, carbon dioxide concentration, and pressure detected in the detection step. In the injection control step, the medium is intermittently injected from the boiler medium injection nozzle so that the injection stop does not continue beyond the maximum stop time of the boiler medium injection nozzle calculated in the injection stop time calculation step.

The boiler medium injection nozzle injects a medium toward, for example, a heat transfer tube of a heat recovery boiler.

The maximum stop time of the boiler medium injection nozzle is the reaction rate of C in the char using _{the temperature, CO 2} concentration and pressure of the gas (produced gas) containing carbon monoxide and hydrogen as the main components flowing through the heat recovery boiler. It can be obtained by calculating and calculating the reaction time from the obtained reaction rate until the C concentration in the char becomes the anti-sinter C concentration.

In the above configuration and method, the char adhering to the heat transfer tube of the heat recovery boiler is periodically blown at intervals within the maximum stop time by the injection of the medium from the boiler medium injection nozzle, and the C concentration in the char is prevented from sintering. It is surely removed from the heat transfer tube before it becomes less than C concentration. That is, the C concentration in the char can be maintained (secured) at or higher than the anti-sintering C concentration, and the occurrence of fouling can be prevented.

Further, since the medium is not always continuously injected from the boiler medium injection nozzle during the gasification operation but intermittently, the operation efficiency can be improved.

According to the present invention, it is possible to improve the efficiency of operation while surely preventing slugging.

It is a schematic diagram which shows the schematic structure of the coal gasification equipment and the blockage prevention device which concerns on one Embodiment of this invention. It is a figure which shows the relationship between the C concentration in char and the degree of sintering. It is a figure which shows the change of the C concentration in char with respect to the residence time, (a) shows by comparing two coals of a different kind, and (b) shows by comparing the case where the same kind of coal has a different gas temperature. There is. It is a flowchart which shows the process which the injection control unit executes.

The coal gasification equipment and the blockage prevention device according to the embodiment of the present invention will be described with reference to FIG. The coal gasification facility of the present embodiment is, for example, a jet bed coal gasification facility used in a multipurpose coal gas production technology (EAGLE: coal Energy Application for Gas, Liquid and Electricity).

As shown in FIG. 1, the coal gasification facility includes a gasification furnace 1 and a heat recovery boiler 2 provided in the wake of the gasification furnace 1.

The internal space of the gasification furnace 1 is roughly divided into a gasification section 3, a heat recovery section 4, and a quench section 5, and is partitioned by a refractory material lined on the inner surface of the steel container. The upper part and the lower part of the gasification part 3 communicate with the lower part of the heat recovery part 4 and the upper part of the quench part 5, respectively, and in the lower part of the gasification part 3, the area of the communication passage with the quench part 5 (flow path cross-sectional area). ) Is reduced.

The gasification section 3 is provided with a pulverized coal burner 7 and a char burner 8. The pulverized coal (coal) carried by the airflow from the fuel supply facility (not shown) is charged from the pulverized coal burner 7 into the gasification section 3 in a high temperature and high pressure state together with an oxidizing agent (for example, air or oxygen). The gasification unit 3 gasifies the combustible component of the input coal, converts it into a gas (produced gas) containing carbon monoxide and hydrogen as main components, and converts the ash component into molten slag. The generated gas flows to the heat recovery unit 4 above the gasification furnace 1, and the temperature of the generated gas drops due to heat exchange with a medium flowing through a heat transfer tube (not shown) arranged around the gasification furnace 1. ..

The generated gas flows from the heat recovery unit 4 to the heat recovery boiler 2, and after the temperature drops due to heat exchange with the medium (water) flowing through the heat transfer tube 9 in the heat recovery boiler 2, it flows out from the heat recovery boiler 2. The dust removal gas 12 and the char are separated by the cyclone 10 (partly the cyclone 10 and the char filter 11), and the dust removal gas 12 is supplied to the outside of the system. Although not shown, the bypass line 29 is provided with a valve, and when the equipment is started or stopped, the bypass line 29 uses all or part of the combustion gas with less dust for heat-up or the nitrogen gas for purging. To protect the char filter. The char separated from the generated gas is stored in the hopper 13, transported via the char transport pipe 14, is charged from the char burner 8 into the gasification furnace 1, and is reused. Further, the molten slag in the gasification furnace 1 flows down from the throttle portion 6 at the lower part of the gasification portion 3 to the quench portion 5, and is discharged to the outside of the system together with the quench water 15. The quench portion 5 is provided with an auxiliary burner 16.

The generated gas flowing through the heat recovery unit 4 of the gasification furnace 1 contains a solid char composed of carbon (C) and ash and molten ash. These chars and molten ash adhere to the wall surface of the heat recovery unit 4, but in the present embodiment, as will be described later, the molten ash is prevented from adhering to each other due to the dispersion action of carbon (C in the char) in the char. , The heat recovery unit 4 is designed so as not to cause slugging. The C concentration in the char that does not cause slugging differs depending on the coal type.

FIG. 2 shows the relationship between the C concentration in char and the degree of sintering for each of the two types of coal (coal A and coal B). When the C concentration in the char is high, the sintering degree of the molten ash decreases, and when the C concentration in the char reaches a predetermined C concentration, the sintering degree becomes 0. The C concentration in char when the degree of sintering becomes 0 is the lowest value of the C concentration in char that prevents molten slag from adhering to each other and sintering, and this concentration is defined as the anti-sintering carbon concentration (anti-sintering). C concentration). If the C concentration in the char of the char adhering to the furnace wall surface of the heat recovery unit 4 of the gasification furnace 1 is equal to or higher than the anti-sintering C concentration, the molten ash is not sintered due to the dispersion action of C in the char, and the heat recovery unit It is possible to prevent slugging on the wall surface of 4. The anti-sintering C concentration differs depending on the coal type, and in the example shown in FIG. 2, the anti-sintering C concentration of coal A (indicated by the solid line in the figure) is 20 wt%, and the anti-sintering C concentration is 20 wt%, and the coal B (indicated by the alternate long and short dash line in the figure). ) Sintering prevention C concentration is 30 wt%.

As shown in FIG. 1, the blockage prevention device includes an injection nozzle (gasifier medium injection nozzle) 17 on the gasifier side, an injection nozzle (boiler medium injection nozzle) 18 on the boiler side, and a thermocouple on the gasifier side. It includes a pair 19, a sampling pipe 20, an analyzer 21, a pressure gauge 22, a thermocouple 23 on the boiler side, and an injection control unit 30.

The injection nozzle 17 on the gasification furnace side is provided in the gasification furnace 1 to blow off and remove the adhering char (char adhering to the furnace wall surface), and injects a predetermined medium 28 into the heat recovery unit 4. The predetermined medium 28 may be an inert gas such as nitrogen gas or a gas refined gas (= recycled gas) for removing corrosive gas such as chlorine and sulfur from the dust removal gas 12. The injection direction of the injection nozzle 17 on the gasification furnace side is set to include the direction along the furnace wall surface of the heat recovery unit 4. The injection nozzle 18 on the boiler side is provided in the heat recovery boiler 2 in order to blow off and remove the adhering char (char adhering to the heat transfer tube 9), and a predetermined medium 28 is used in the internal space of the heat recovery boiler 2 (of the generated gas). Inject into the distribution space). The injection nozzle 18 on the boiler side is arranged on the inflow side (gas inlet side) of the generated gas, and the injection direction thereof is set to include the direction toward the heat transfer tube 9 in the boiler. In the example of FIG. 1, the injection nozzle 17 on the gasifier side is provided on one side of the heat recovery unit 4 in three upper and lower stages, one for each stage, but the number of stages to be set is arbitrary and each. A plurality of injection nozzles 17 may be installed concentrically in the stage. Similarly, although one injection nozzle 18 on the boiler side is provided on one side of the heat recovery boiler 2, a plurality of injection nozzles 18 may be installed concentrically. The medium 28 to be injected from each of the injection nozzles 17 and 18 is not particularly limited, and may be nitrogen gas, or may be recycled gas that has been refined by removing solids such as char from the produced gas.

A gasifier that individually executes and stops the injection of the medium 28 from each injection nozzle 17 (controls the supply of the injection medium to the injection nozzle 17) in the medium supply pipe 24 of each injection nozzle 17 on the gasification furnace side. A control valve 26 on the side is provided. Similarly, the control valve 27 on the boiler side executes and stops the injection of the medium 28 from the injection nozzle 18 (controls the supply of the injection medium to the injection nozzle 18) in the medium supply pipe 25 of the injection nozzle 18 on the boiler side. Is provided.

The thermocouple 19 on the gasifier side measures the temperature of the produced gas flowing through the heat recovery unit 4, and the thermocouple 23 on the boiler side measures the temperature of the produced gas flowing in the internal space of the heat recovery boiler 2. The sampling pipe 20 communicates with the heat recovery unit 4 at the wake of the temperature measurement position by the thermocouple 19 on the gasifier side, and the analyzer 21 communicates with the carbon dioxide of the generated gas flowing from the heat recovery unit 4 into the sampling pipe 20. Measure the concentration (CO ₂ concentration). The pressure gauge 22 measures the pressure inside the gasification furnace 1 (the pressure of the heat recovery unit 4). That is, the thermocouple 19, the analyzer 21, and the pressure gauge 22 on the gasifier side _{detect the temperature, CO 2} concentration, and pressure of the gas containing carbon monoxide and hydrogen as main components flowing through the heat recovery unit 4. The thermocouple 23 on the boiler side functions as a detection means for detecting the temperature of a gas containing carbon monoxide and hydrogen as main components flowing in the internal space of the heat recovery boiler 2. As the pressure gauge 22, one provided for controlling the gasifier 1 may be used.

In the present embodiment, the sampling pipe 20 is communicated with the gas outlet side of the heat recovery unit 4, and the CO ₂ concentration of the generated gas is measured on the gas outlet side of the heat recovery unit 4, so that the gas inlet side of the heat recovery boiler 2 is measured. The measurement of the CO ₂ concentration in the above is omitted, and the CO ₂ concentration measured by the analyzer 21 on the gasifier side is also used as _{the CO 2} concentration of the generated gas on the heat recovery boiler 2. An analyzer for measuring the CO ₂ concentration may be separately provided. Similarly, regarding the pressure, the pressure measured by the pressure gauge on the gasifier side is also used as the pressure on the heat recovery boiler 2, but a pressure gauge may be provided separately on the boiler side.

The injection control unit 30 controls the opening and closing of the control valves 26 and 27 while the gasification operation is being executed, and intermittently injects the medium 28 from the injection nozzles 17 and 18 on the gasification furnace side and the boiler side.

The char adhering to the furnace wall surface of the heat recovery unit 4 of the gasification furnace 1 during the execution of the gasification operation is generated as shown in the following equation (1) until it is removed by the medium injection from the injection nozzle 17. It is gasified by CO _{2 in the} gas and converted to CO. Further, this CO is converted into _{CO 2} and H ₂ by the reaction with _{H 20} as shown in the following formula (2).

C + CO → 2CO ... (1)
CO + H ₂ O → CO ₂ + H ₂ ... (2)

Therefore, the C concentration in the char is reduced by the residence time of the char adhering to the wall surface of the gasification facility (the wall surface of the gasification furnace 1 or the surface of the heat transfer tube 9 of the heat recovery boiler 2). The gasification reaction rate of C in the char is generally expressed by the following equation (3).

k = P _CO2・ A ・ exp (-E / (RT)) ・ ・ ・ (3)
Here, k: reaction rate of char, P _CO2 : CO ₂ partial pressure of _{produced gas (= CO 2} concentration × pressure P), A: frequency factor, E: activation energy, R: gas constant, T: gas temperature. Is.

FIG. 3 is a diagram showing the change in the C concentration in the char with respect to the residence time, and the change in the C concentration in the char with respect to the residence time was obtained by the equation (3) under the condition that the gasifier load was constant. FIG. 3A is an example of a change in the C concentration in the char in an atmosphere having a gas temperature of 1200 ° C., and FIG. 3B is an example of a change in the C concentration in the char due to a difference in the gas temperature in the coal A. .. As shown in FIG. 3A, the C concentration in the char gradually decreases due to the reactions of the formulas (1) and (2). The decreasing tendency of C concentration in char differs depending on the coal type, and the time to anti-sintering C concentration (maximum stop time of injection nozzles 17 and 18) tb is the condition of gas temperature 1200 ° C., and coal A prevents sintering. TbA (tbA1) = 10 minutes up to the C concentration (20 wt%), and tbB = 7 minutes up to the anti-sintering C concentration (30 wt%) for coal B. As shown in FIG. 3B, the time required for the coal A to reach the anti-sintering C concentration (20 wt%) under the condition of a gas temperature of 1000 ° C. is 30 minutes (tbA2 = 30 minutes). It can be seen that the higher the gas temperature, the higher (faster) the gasification reaction rate of C in the char, and the shorter the time is up to the anti-sintering C concentration.

After the char adheres to the furnace wall surface of the heat recovery unit 4, or after the char adheres to the heat transfer tube 9 of the heat recovery boiler 2, the injection nozzle 17 is every time tb when the C concentration in the char reaches the anti-sintering C concentration. By blowing off and removing the char attached by the injection medium (injected medium 28) from 18 and 18, the slugging and fouling in the furnace wall of the heat recovery unit 4 and the heat transfer tube 9 of the heat recovery boiler 2 are prevented. It becomes possible. Further, the char blown off by the heat recovery unit 4 flows together with the generated gas to the heat recovery boiler 2 which is the wake of the heat recovery unit 4. By surely keeping the C concentration in the char at the anti-sintering C concentration or higher in the heat recovery unit 4, even if the char adheres to the heat transfer tube 9 of the heat recovery boiler 2, the char accumulated by the injection nozzle 18 can be easily removed. , It can contribute to the prevention of fouling in the heat recovery boiler 2.

The injection control unit 30 is composed of, for example, a computer, and functions as a storage unit 31, a calculation unit (injection stop time calculation means) 32, and a control unit (injection control means) 33, as shown in FIG.

In the storage unit 31, the anti-sintering C concentration of the test coal is set and stored by input from the operator or the like.

The calculation unit 32 uses the thermoelectric pair 19 on the gasifier side, the gas temperature, CO ₂ concentration and pressure of the produced gas measured by the analyzer 21 and the pressure gauge 22, and the heat recovery unit 4 using the equation (3). The gasification reaction rate of C in the char is calculated, and the time until the carbon concentration in the char (C concentration in the char) of the heat recovery unit 4 decreases to the anti-sinter carbon concentration stored in the storage unit 31 (gas). The maximum stop time) tb of the injection nozzle 17 on the conversion furnace side is calculated from the gasification reaction rate obtained above. _{Similarly, the heat recovery boiler using the gas temperature, CO 2} concentration and pressure of the produced gas measured by the thermocouple 23 on the boiler side, the analyzer 21 on the gasifier side and the pressure gauge 22, and the equation (3). The gasification reaction rate of C in the char in No. 2 is calculated, and the time until the carbon concentration in the char of the heat recovery boiler 2 decreases to the anti-sinter carbon concentration stored in the storage unit 31 (injection nozzle 18 on the boiler side). (Maximum stop time) tb is calculated from the gasification reaction rate obtained above. If an analyzer and / or pressure gauge is installed on the boiler side, the CO ₂ concentration and / or pressure measured by the analyzer and / or pressure gauge on the boiler side is used in the heat recovery boiler 2. Calculate the gasification reaction rate of C in the char.

The control unit 33 controls the control valve 26 so that the injection stop does not continue beyond the maximum stop time tb of the injection nozzle 17 on the gasifier side obtained by the calculation unit 32, and the injection nozzle 17 on the gasifier side. The medium 28 is intermittently ejected from. Similarly, the control valve 27 is controlled so that the injection stop does not continue beyond the maximum stop time tb of the injection nozzle 18 on the boiler side obtained by the calculation unit 32, and the medium 28 is intermittently transmitted from the injection nozzle 18 on the boiler side. To inject. In the present embodiment, control is executed in which injection is performed at intervals of the longest stop time so as to repeat injection for a predetermined time and injection stop for the longest stop time. The injection time (predetermined time) is set in advance to a certain time during which the adhered char can be reliably blown off.

Next, the process executed by the injection control unit 30 will be described with reference to the flowchart of FIG.

When this process is started, first, the anti-sintering C concentration of the test coal in the heat recovery unit 4 and the heat recovery boiler 2 is set and stored (step S1). Since the test coals in the heat recovery unit 4 and the heat recovery boiler 2 are of the same type, a common anti-sintering C concentration is set.

After setting the anti-sintering C concentration, the gas temperature, CO ₂ concentration and pressure of the produced gas are detected, respectively (step S2). Specifically, the gas temperature measured by the thermocouples 19 and 23 on the gasifier side and the boiler side, the CO ₂ concentration measured by the analyzer 21, and the pressure measured by the pressure gauge 22 are acquired, respectively.

Next, using the thermoelectric pair 19 on the gasifier side, the gas temperature, CO ₂ concentration and pressure of the produced gas measured by the analyzer 21 and the pressure gauge 22, and the equation (3), the heat recovery unit 4 is used. The gasification reaction rate of C in the char is calculated, and the time until the carbon concentration in the char of the heat recovery unit 4 decreases to the anti-sinter carbon concentration stored in step S1 (the longest stop of the injection nozzle 17 on the gasification furnace side). Time, injection interval time) tb is calculated from the gasification reaction rate obtained above (step S3). _{Similarly, the heat recovery boiler using the gas temperature, CO 2} concentration and pressure of the produced gas measured by the thermocouple 23 on the boiler side, the analyzer 21 on the gasifier side and the pressure gauge 22, and the equation (3). The gasification reaction rate of C in the char in step 2 is calculated, and the time until the carbon concentration in the char of the heat recovery boiler 2 decreases to the anti-sintering carbon concentration stored in step S1 (the longest of the injection nozzle 18 on the boiler side). The stop time (injection interval time) tb is calculated from the gasification reaction rate obtained above (step S3). Since the processes after step S2 are executed independently (in parallel) on the gasifier side and the boiler side in the same manner, the gasifier side and the boiler side will be described below without distinguishing them.

Next, whether or not the elapsed time (injection stop time) t from the previous injection stop has reached the maximum stop time tb (whether or not the count value of the injection stop time measurement timer (internal timer) has reached tb). (Step S4), when the injection stop time t reaches the maximum stop time tb (step S4: Yes), the control valves 26 and 27 are controlled to inject the medium 28 from the injection nozzles 17 and 18. It starts, resets the count value of the injection stop time measurement timer (t = 0), and starts counting the injection time by the injection time measurement timer (internal timer) (step S5).

The injection strength and the amount of gas (injection amount) do not have to be constant from beginning to end during the injection time, and the strength and the amount of gas may be changed in a pulsed manner, and the injection method is not particularly limited.

Further, the determination in step S4 described above is determined as to whether or not the elapsed time (injection stop time) t from the previous injection stop has reached ts, with an arbitrary time ts shorter than the longest stop time tb as a set value. It may be that.

Next, it is determined whether or not the injection time has reached the predetermined time set in advance (whether or not the count value of the injection time measurement timer has reached the predetermined time) (step S6), and the injection time reaches the predetermined time. When it reaches (step S6: Yes), the control valves 26 and 27 are controlled to stop the injection of the medium 28 from the injection nozzles 17 and 18, reset the count value of the injection time measurement timer, and measure the injection stop time. The timer starts counting the injection time (step S7).

The determination of whether or not the count value of the injection stop time measurement timer has reached tb (step S4) is repeated until the count value tb is reached, and whether or not the count value of the injection time measurement timer has reached a predetermined time. (Step S6) is repeated until the count value reaches a predetermined time. As a result, the injection for a predetermined time and the injection stop for the longest stop time tb are repeatedly executed.

Next, it is determined whether or not to stop the injection (step S8), and if it is not stopped (step S8: No), the process proceeds to step S2 and the processes of steps S2 to S8 are repeated. On the other hand, when stopping (step S8: Yes), this process ends. The processes of steps S2 to S8 are always and repeatedly executed during the execution of the gasification operation. For example, when the gasification operation is terminated, it is determined in step S8 that the injection is stopped, and this process is terminated.

As described above, according to the present embodiment, the char adhering to the furnace wall surface of the heat recovery unit 4 of the gasification furnace 1 is periodically generated at intervals within the maximum stop time by the injection of the medium 28 from the injection nozzle 17. It is blown and surely removed from the furnace wall surface before the C concentration in the char becomes less than the anti-sintering C concentration. That is, the C concentration in the char can be maintained (secured) at or higher than the anti-sintering C concentration, slugging can be reliably prevented, and fouling in the heat recovery boiler 2 can be suppressed. Therefore, it is possible to prevent the gasification equipment from being blocked by scattered ash and char (blockage of the gas flow path), realize stable operation of the gasification equipment, and improve reliability.

Further, also in the heat recovery boiler 2, the char adhering to the heat transfer tube 9 is periodically blown at intervals within the longest stop time by the injection of the medium 28 from the injection nozzle 18, and the C concentration in the char is prevented from sintering. It is surely removed from the heat transfer tube 9 before it becomes less than C concentration. That is, the C concentration in the char can be maintained (secured) at or higher than the anti-sintering C concentration, and the occurrence of fouling can be reliably prevented.

Further, since the injection of the medium 28 from the injection nozzles 17 and 18 is not always continuously performed during the gasification operation but is performed intermittently, the operation efficiency can be improved.

The present invention is not limited to the above-described embodiment and modification described as an example, and is not limited to the above-described embodiment and the like as long as it does not deviate from the technical idea of the present invention. , Various changes are possible depending on the design and the like.

For example, the injection nozzles 17 and 18 may not be provided on both the gasifier side and the boiler side, and the injection nozzles 17 may be provided only on the gasifier side. Further, the injection nozzles 18 on the boiler side may be provided in a plurality of stages.

1: Gasification furnace 2: Heat recovery boiler 3: Gasification section 4: Heat recovery section 5: Quenching section 6: Squeezing section 7: Microcarbon burner 8: Char burner 9: Heat recovery boiler heat transfer tube 10: Cyclone 11: Char filter 12: Dust removal gas 13: Hopper 14: Char transport pipe 15: Quench water 16: Auxiliary burner 17: Gasifier side injection nozzle (gasifier medium injection nozzle)
18: Boiler side injection nozzle (boiler medium injection nozzle)
19: Thermocouple on the gasifier side (detection means)
20: Sampling pipe 21: Analyzer (detection means)
22: Pressure gauge (detection means)
23: Thermocouple on the boiler side (detection means)
24, 25: Control signal line or valve operating medium supply pipe 26, 27: Control valve 28: Predetermined medium 29: Bypass line 30: Injection control unit 31: Storage unit 32: Calculation unit (injection stop time calculation means) )
33: Control unit (injection control means)

Claims (4)

A gasification unit that converts coal into a gas containing carbon monoxide and hydrogen as main components by putting it into a furnace together with an oxidizing agent and heating it, and also converts ash in coal into molten slag, and the gasification unit. An blockage prevention device provided in a coal gasification facility provided with a gasification furnace having a heat recovery unit communicating with the gasification unit, which is arranged above the coal gasification unit.
A gasifier medium injection nozzle capable of injecting a predetermined medium into the heat recovery unit,
A detection means for detecting the temperature, carbon dioxide concentration, and pressure of a gas containing carbon monoxide and hydrogen as main components flowing through the heat recovery unit.
The time until the carbon concentration in the char of the heat recovery section decreases to the anti-sintering carbon concentration, which is the minimum value of the carbon concentration in the char that prevents the molten slag from adhering to each other and sintering in the heat recovery section. As the maximum stop time of the gasifier medium injection nozzle, an injection stop time calculation means calculated by using the temperature, carbon dioxide concentration, and pressure detected by the detection means, and an injection stop time calculation means.
Injection control for intermittently injecting the medium from the gasifier medium injection nozzle so that the medium injection stop does not continue beyond the maximum stop time of the gasifier medium injection nozzle calculated by the injection stop time calculation means. A blockage prevention device for coal gasification equipment, characterized in that it is equipped with means. The blockage prevention device according to claim 1, which is provided in the coal gasification facility provided with a heat recovery boiler in the wake of the gasification furnace.
A boiler medium injection nozzle capable of injecting a predetermined medium is provided inside the heat recovery boiler.
The detection means detects at least the temperature of a gas containing carbon monoxide and hydrogen as main components flowing through the heat recovery boiler.
The injection stop time calculating means has the char carbon concentration in the char of the heat recovery boiler to the sintering prevention carbon concentration which is the minimum value of the char carbon concentration for preventing molten slags from adhering to each other and sintering in the heat recovery boiler. The time until the decrease is calculated as the maximum stop time of the boiler medium injection nozzle by using the temperature, the carbon dioxide concentration, and the pressure detected by the detection means.
The injection control means intermittently injects a medium from the boiler medium injection nozzle so that the injection stop of the medium does not continue beyond the maximum stop time of the boiler medium injection nozzle calculated by the injection stop time calculation means. A blockage prevention device for coal gasification equipment. A gasification unit that converts coal into a gas containing carbon monoxide and hydrogen as main components by putting it into a furnace together with an oxidizing agent and heating it, and also converts ash in the coal into molten slag, and the gasification unit. A gasification furnace medium injection nozzle capable of injecting a predetermined medium into the heat recovery unit is provided in a coal gasification facility provided with a gasification furnace having a heat recovery unit communicating with the gasification unit, which is arranged above the heat recovery unit. It is a method of preventing blockage in the provided coal gasification facility.
A detection step for detecting the temperature, carbon dioxide concentration, and pressure of a gas containing carbon monoxide and hydrogen as main components flowing through the heat recovery unit.
The time until the carbon concentration in the char of the heat recovery section decreases to the anti-sintering carbon concentration, which is the minimum value of the carbon concentration in the char that prevents the molten slag from adhering to each other and sintering in the heat recovery section. As the maximum stop time of the gasifier medium injection nozzle, an injection stop time calculation step calculated using the temperature, carbon dioxide concentration, and pressure detected in the detection step, and an injection stop time calculation step.
With the injection control step of intermittently injecting the medium from the gasifier medium injection nozzle so that the injection stop does not continue beyond the maximum stop time of the gasifier medium injection nozzle calculated in the injection stop time calculation step. A method for preventing blockage of coal gasification equipment, which is characterized by providing. A claim in the coal gasification facility in which the coal gasification facility provided with a heat recovery boiler in the wake of the gasification furnace is provided with a boiler medium injection nozzle capable of injecting a predetermined medium inside the heat recovery steam. The blockage prevention method according to 3.
In the detection step, at least the temperature of the gas containing carbon monoxide and hydrogen as main components flowing through the heat recovery boiler is detected.
In the injection stop time calculation step, the carbon concentration in the char of the heat recovery boiler is set to the sintering prevention carbon concentration which is the minimum value of the carbon concentration in the char that prevents the molten slags from adhering to each other and sintering in the heat recovery boiler. The time until the decrease is calculated as the maximum stop time of the boiler medium injection nozzle using the temperature, carbon dioxide concentration, and pressure detected in the detection step.
In the injection control step, the medium is intermittently injected from the boiler medium injection nozzle so that the injection stop does not continue beyond the maximum stop time of the boiler medium injection nozzle calculated in the injection stop time calculation step. A characteristic method for preventing blockage of coal gasification equipment.

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