JP2015025091A - Operation method of gasifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve stable discharge of a crushed water cooled slag by flowing down a molten slag discharged from a gasification furnace in water.SOLUTION: There is provide the operational method of a gasification furnace 5 for gasifying coal 41 which includes in a lower part of the gasification furnace 5, a quench part 13 for pooling water, and which melts a gasification residue of the coal 41 in the gasification furnace 5 to obtain a molten slag 59, and separates a water cooled slag obtained by flowing down the molten slag 59 in water of the quench part 13 from water, In the operational method, a degree of basicity of an ash content of the coal 41 obtained by dividing a total weight ratio of CaO, FeO, MgO, MnO, NaO, Kby a total weight ratio of at least SiO, AlO, PO, TiOof basic oxide is set to 0.21 or more so that a generation ratio of a filamentous slag contained in the water cooled slag is set to equal to or lower than a setting ratio of the weight ratio of total water cooled slag. If the degree of basicity of the ash in the coal is less than 0.21, basic oxide is added to and mixed with the coal.

Description

  The present invention relates to an operation method of a gasifier, and in particular, a molten gas slag discharged from a coal gasifier is crushed by flowing it into water, and the crushed water-cooled slag is separated from the water. About.

  A gasification furnace that gasifies coal supplies finely pulverized coal together with an oxidizing agent such as oxygen or air into a high-temperature furnace maintained at a temperature equal to or higher than the melting temperature of the ash contained in the coal, and controls the combustible content. It is converted into a gas mainly composed of carbon oxide and hydrogen, and ash is converted into molten slag.

  This type of gasification furnace includes a quench unit, a gasification unit, and a heat recovery unit from below in a pressure vessel. An oxidizer and pulverized coal are supplied to the gasification section via a burner, and the furnace temperature equal to or higher than the melting temperature of ash is maintained. Therefore, the ash content in the coal becomes molten slag in the gasification section, flows down to the furnace wall of the gasification section, and flows down to the quench section through a slag tap opened at the bottom of the gasification section. Water is stored in the quench section, and the molten slag falling into the water is rapidly cooled to become water-cooled slag. This water-cooled slag becomes a granular material of about several millimeters by being crushed by receiving a thermal shock in water. Hereinafter, the operation of crushing the molten slag in water is referred to as water granulation, and a granular material of about several millimeters of water-cooled slag obtained by the water granulation is referred to as granulated slag. Underwater granulated slag is extracted from the quenching section together with water, and is crushed to a predetermined particle size and collected.

  By the way, in order to stably operate this type of gasification furnace, it is important to reliably convert molten slag into granulated slag. In this respect, if the molten slag stays in the gasification section or the molten slag adheres to the slag tap and the discharge of the molten slag is impeded, the operation of the gasification furnace must be stopped.

  In patent document 1, in order to prevent a slag tap being obstruct | occluded with molten slag, the technique which heats the vicinity of a slag tap with an auxiliary burner and improves the fluidity | liquidity of the molten slag which passes a slag tap is disclosed.

  Moreover, in patent document 2, according to the CaO density | concentration in the ash content of the coal to be used, this coal is mixed with a calcium compound, and by adjusting the CaO concentration of the molten slag to a predetermined range, the flow state of the molten slag is changed. A stabilizing technique is disclosed.

  However, some of the molten slag may be converted into a thread-like water-cooled slag (hereinafter referred to as a thread-like slag as appropriate) having a property that the slags are entangled without being crushed in water. When this type of water-cooled slag is discharged from the quenching section, for example, it may become entangled at the line branching section of the slag discharge system, etc., and the discharge line may be blocked, and this will cause the stable discharge of the water-cooled slag. This water-cooled slag threading may occur even when the fluidity of the molten slag is increased by the techniques of Patent Document 1 and Patent Document 2.

In Patent Document 3, in order to prevent clogging of the slag discharge system due to water-cooled slag, the basicity of the molten slag (weight ratio obtained by dividing CaO by SiO ₂ ) is in the range of 0.3 to 1.2. Describes adding a regulator to raw coal. According to this, since the production | generation ratio of filamentous slag can be reduced, it is supposed that the clogging of the water-cooled slag in a slag discharge system can be suppressed.

Japanese Patent No. 3924224 JP 2005-126629 A JP 2012-193246 A

Incidentally, in Patent Document 3, and we evaluated the form of the form and a water-cooled slag when molten slag flows down in the basicity of the two oxides of CaO and SiO _2. However, the ash content of coal, other CaO and SiO _2, includes _{Al 2 O 3, Fe 2 O} 3, MgO, MnO, Na 2 O, K 2 O, and a number of oxides _TiO 2, _{P 2} 0 Even if coal having the same basicity required from two kinds of oxides of CaO and SiO ₂ is used, there are cases where most of the granulated slag is granulated and a relatively large amount of filamentous slag is generated.

That is, since the form of the granulated slag varies depending on the composition and content of oxides other than CaO and SiO ₂ , the basicity of the molten slag is determined by the method of Patent Document 3, Even if the form of slag is evaluated, it is difficult to achieve stable discharge of water-cooled slag.

  An object of the present invention is to realize stable discharge of water-cooled slag by more accurately evaluating the form of the water-cooled slag.

  The inventors of the present invention conducted a molten slag flow-down / water-cooling test using a laboratory scale test apparatus. The molten slag flow-down / water-cooling test method involves heating a sample (coal ashed sample or slag) above the melting temperature to form molten slag, and dropping this molten slag into a water tank that simulates the quenching section of a gasification furnace. Rapid cooling was performed by observing the flow of molten slag at that time and the appearance of the water-cooled slag in the water tank. As samples, coal having a high ash melting temperature and coal having a low ash melting temperature were used, and the coal having a high ash melting temperature was heated to a temperature higher than that of the coal having a low ash melting temperature and melted. As a result, in any case of coal, water-cooled slag (granulated slag) that has been granulated and granulated as shown in FIG. 1 (c) and not granulated as shown in FIGS. 1 (a) and 1 (b). Both water-cooled slag (hereinafter abbreviated as thread-like slag) was confirmed.

From this result, the present inventors speculated that whether the water-cooled slag is granulated or thread-formed is due to factors other than the temperature and fluidity of the molten slag. The coal ash contains various oxides such as SiO ₂ , Al ₂ O ₃ , and CaO. The present inventors paid attention to the oxides constituting these ash contents, and examined the relationship between the formation of water-cooled slag thread and the ash composition. Specifically, multiple samples with different compositions of various oxides in ash were prepared, and each sample was subjected to a molten slag flow / water cooling test using a laboratory-scale test device to determine the production rate of filamentous slag. investigated. The production rate of the filamentous slag was obtained by recovering the water-cooled slag from the water tank and drying it, and then passing it through a sieve with a certain mesh size to obtain the weight ratio on the sieve based on the total amount of the water-cooled slag.

As a result of evaluating the relation between the generation rate of the filamentous slag and the ash composition, the generation of the filamentous slag using the CaO concentration of the coal ash and the basicity of the ash shown in the formula (1) (hereinafter simply referred to as basicity). It was found that the tendency of granulation and threading of water-cooled slag can be clearly distinguished by organizing the ratio. Further, in addition to the basicity and CaO concentration of ash, the concentration of each oxide shown in the molecule of the formula (1), CaO / SiO ₂ , SiO ₂ concentration of ash, Al ₂ O ₃ concentration of ash are evaluated in the same manner. However, it was possible to better represent the tendency of the molten slag to become filamentous by arranging by the basicity of the ash and the CaO concentration.
Basicity = total weight ratio (wt%) of at least CaO, Fe ₂ O ₃ , MgO, MnO, Na ₂ O, K ₂ O among basic oxides / at least SiO ₂ , Al ₂ O ₃ among acidic oxides , P ₂ O ₅ , TiO ₂ total weight ratio (wt%) (1)

  Next, the present inventors examined whether the basicity or CaO concentration of coal ash can be used as an index for granulation or filamentation of water-cooled slag from the test results. FIG. 2 shows the relationship between the generation ratio (wt%) of the filamentous slag with respect to the total slag and the basicity (wt% / wt%) of coal ash, and FIG. %) And the CaO concentration (wt%) of coal ash. As shown in FIGS. 2 and 3, when the basicity of ash and the CaO concentration are increased, the generation rate of filamentous slag is rapidly reduced. Then, molten slag having different ash basicity and CaO concentration was caused to flow from the gasification furnace to quench water, water-cooled slag having different filamentous slag generation rates was generated, and the discharge status of each water-cooled slag was confirmed. When the production rate of thread-like slag with respect to slag is 10 wt% as a boundary, the tendency of water-cooled slag to be fibrillated and granulated (hydrocracked) can be clearly distinguished. It was confirmed that slag discharge was stable.

  Therefore, as a standard for stabilizing the discharge of the water-cooled slag, the production rate of the filamentous slag was set to 10 wt% or less. As a result, the basicity of coal ash content is 0.21 from FIG. 2, and the CaO concentration of coal ash content is 6 wt% from FIG. That is, if the basicity of the ash content of coal supplied to the gasification furnace is 0.21 or more, the production rate of filamentous slag with respect to the total water-cooled slag of the coal can be kept low, and stable discharge of slag becomes possible. . And, in addition to the basicity being 0.21 or more, if the CaO concentration in the ash of coal is 6 wt% or more, the production rate of filamentous slag to the total water-cooled slag of coal is further stable in the range of 10 wt% or less. Therefore, stable discharge of the water-cooled slag can be realized more reliably.

  Based on the above results, in the present invention, in order to solve the above-mentioned problem, a quenching section for storing water is provided at the lower part of the gasification furnace for gasifying coal, and the gasification residue of coal is melted in the gasification furnace. In the operation method of the gasification furnace that separates the water-cooled slag obtained by letting the molten slag flow into the water of the quenching section from the water, the production rate of the filamentous slag contained in the water-cooled slag is the weight of the whole water-cooled slag. In order to make the ratio less than the set ratio, the basicity of coal ash calculated by the following formula is 0.21 or more.

  According to this, since the production | generation ratio of the thread-like slag contained in water-cooled slag can be suppressed to 10 wt% or less, the stable discharge of water-cooled slag is attained, and the stable operation | movement of a gasification furnace is realizable.

  In this case, when the basicity of the ash content of the coal is less than 0.21, the basic oxide is mixed with the coal and the basicity of the ash content of the mixed powder after mixing is adjusted to 0.21 or more. The adjusted mixed powder is put into a gasifier.

  In this way, the same effect as when coal having a basicity of 0.21 or more is introduced into the gasifier by introducing the mixed powder prepared by mixing the basic oxide into the coal into the gasifier. Can be obtained. As the basic oxide, calcium carbonate can be used in addition to each oxide of the molecule of the formula (1).

  Moreover, it can replace with a basic oxide and can use adjustment coal. That is, when the basicity of the ash content of coal is less than 0.21, the adjustment coal having a basicity of 0.21 or more is mixed to adjust the basicity of the mixed coal after mixing to 0.21 or more. Even if the mixed coal thus adjusted is charged into the gasifier, the same effect as when coal having an ash content of 0.21 or more is charged into the gasifier can be obtained.

  Moreover, in addition to setting the basicity of coal ash to 0.21 or more, by making the CaO concentration of coal ash to 6 wt% or more, it is possible to stabilize the production rate of filamentous slag within a range of 10 wt% or less. It is possible to stably discharge the granulated slag more reliably. Here, when the CaO concentration of coal ash is less than 6 wt%, this coal is mixed with a calcium compound such as calcium carbonate or calcium hydroxide to form a mixed powder, or mixed with coal for adjustment. As a result, the CaO concentration of mixed powder or ash of mixed coal is adjusted to 6 wt% or more. Even if the mixed powder and mixed coal thus adjusted are introduced into the gasifier, coal having an ash content of 0.21 or more and a CaO concentration of 6 wt% or more is introduced into the gasifier. The same effect as that obtained can be obtained.

  According to the present invention, since the form of the water-cooled slag can be more accurately evaluated, stable discharge of the water-cooled slag can be realized.

It is a figure which shows the form of water-cooled slag, (a) and (b) are filamentous slag, (c) represents the granulated slag. It is a figure which shows the relationship between the basicity (wt% / wt%) of the ash content of coal, and the production | generation ratio (wt%) of the filamentous slag with respect to granulated slag. It is a figure which shows the relationship between the CaO density | concentration (wt%) in the ash of coal, and the production | generation ratio (wt%) of the filamentous slag with respect to water-cooled slag. It is a schematic system diagram of the coal gasifier applied to the first and third embodiments of the present invention. It is a figure explaining a mode that molten slag is converted into granulated slag. It is a flowchart explaining the operation | movement procedure of the operating method of the gasifier applied to the 1st and 2nd embodiment of this invention. It is a schematic system diagram of the coal gasifier applied to the second and fourth embodiments of the present invention. It is a flowchart explaining the operation | movement procedure of the operating method of the gasifier applied to the 2nd and 4th embodiment of this invention.

(First embodiment)
Hereinafter, a first embodiment to which an operation method of a coal gasification furnace according to the present invention is applied will be specifically described with reference to the drawings.

  FIG. 4 shows a schematic system diagram of a coal gasifier suitable for carrying out the operation method of the gasifier of the present invention. The coal gasifier includes a gasification furnace 5 including pulverized coal burners 1a and 1b and char burners 3a and 3b, a pulverized coal supply device 7, and an oxide supply device 9.

  The gasification furnace 5 includes a pressure vessel 11 disposed with its axis line oriented in the vertical direction as a main body of the furnace, and includes a quenching unit 13, a gasification unit 15, and a heat recovery unit 17 in order from the bottom in the pressure vessel 11. The pulverized coal burners 1 a and 1 b and the char burners 3 a and 3 b are all provided in the gasification unit 15 and arranged so that the ejection direction is in contact with the virtual circle diameter of the gasification unit 15. With this arrangement, the pulverized coal and char ejected from the pulverized coal burners 1 a and 1 b and the char burners 3 a and 3 b form a swirling flow in the gasification unit 15.

  Between the quench part 13 and the gasification part 15 arrange | positioned above it, the slag tap 19 opened to the bottom part of the gasification part 15 and the top part of the quench part 13 is provided, respectively. A slag discharge line 21 is connected to the bottom of the quench unit 13, and quench water 23 is stored inside the quench unit 13. In the slag discharge line 21, a crusher 25 and a slag discharge valve 27 are arranged in this order from the upstream side. An auxiliary burner 29 for heating the vicinity of the slag tap 19 is provided on the wall surface above the water surface of the quench water 23 of the quench unit 13.

  In FIG. 4, the quench unit 13 is provided in the pressure vessel 11 of the gasification furnace 5, but is provided below the pressure vessel 11 separated from the pressure vessel 11 and in the lower part of the gasification furnace. It may be done. The crusher 25 may be provided below the quench water 23 stored in the quench unit 13.

  A gas discharge line 31 is connected to the top of the pressure vessel 11. The gas discharge line 31 is connected to gas purification equipment such as a dust removal device, a water washing tower, and a desulfurization device (not shown).

  The pulverized coal supply device 7 includes a coal pulverizer 33, a pulverized coal hopper 35, a rotary feeder 36, and a distributor 37. The coal pulverizer 33, the pulverized coal hopper 35, the rotary feeder 36 and the distributor 37 are connected to each other via a pulverized coal supply line 39. The pulverized coal supply line 39 is connected to the pulverized coal burners 1a and 1b, respectively. Yes. Coal crusher 33 is supplied with coal 41 and air 43. The coal 41 supplied to the coal pulverizer 33 is pulverized into pulverized coal, and then air-flowed to the pulverized coal hopper 35 via the pulverized coal supply line 39 and temporarily stored. The pulverized coal cut out by the rotary feeder 36 from the pulverized coal hopper 35 is accompanied by the supplied nitrogen 45, passes through the distributor 37, passes through the pulverized coal supply line 39, and flows into the pulverized coal burners 1a and 1b. Be transported.

  The oxide supply device 9 includes an oxide hopper 47, a rotary supply 48, and a distributor 49. The oxide hopper 47, the rotary feeder 48 and the distributor 49 are connected to each other via an oxide supply line 51, and one end of the oxide supply line 51 is connected to the pulverized coal supply line 39. The oxide hopper 47 stores a powdery basic oxide. The basic oxide cut out from the oxide hopper 47 by the rotary feeder 48 is accompanied by the supplied nitrogen 53, passes through the oxide supply line 51 via the distributor 49, and goes to the pulverized coal supply line 39. Airflow is conveyed. Thereby, the mixed powder in which the pulverized coal and the oxide are mixed is supplied to the pulverized coal burners 1 a and 1 b through the pulverized coal supply line 39. The pulverized coal burners 1a and 1b are supplied with oxygen 55 as an oxidant from a pulverized coal supply line 39 and a separate supply line.

  Next, a basic operation method of the pulverized coal supply device 7 and the gasification furnace 5 of the coal gasifier configured as described above will be described.

  The pulverized coal of the coal 41 supplied to the pulverized coal burners 1 a and 1 b through the pulverized coal supply line 39 is injected into the high-temperature gasification unit 15 together with the oxygen 55. The pulverized coal and oxygen 55 injected into the gasification unit 15 form a swirling flow in the gasification unit 15, and a reaction time for gasification is secured. In the gasification part 15, the furnace temperature more than the melting temperature of the ash content of pulverized coal is maintained.

  In the gasification part 15, the combustible part of the pulverized coal put into the furnace is converted into a gas mainly composed of carbon monoxide and hydrogen. The generated gas generated here is discharged out of the furnace through the gas discharge line 31 through the heat recovery unit 17 provided above the gasification unit 15. The generated gas discharged to the outside of the furnace is used as fuel for power generation equipment after being subjected to processing such as dedusting and desulfurization. The char 57 in the product gas is collected by a cyclone or char filter (not shown) and returned to the furnace again through the char burners 3a and 3b.

  On the other hand, the ash content of the pulverized coal charged into the furnace becomes molten slag 59, flows along the furnace wall of the gasification unit 15, and flows down to the quench unit 13 through the slag tap 19. As shown in FIG. 5, the molten slag 59 that has flowed down to the quench unit 13 falls into the quench water 23 and becomes a water-cooled slag 61. The water-cooled slag 61 is extracted out of the furnace together with the quench water 23 through the slag discharge line 21 when the slag discharge valve 27 is opened. The water-cooled slag 61 extracted outside the furnace is crushed to a predetermined particle size by the crusher 25 and then discharged from the coal gasifier.

  Next, an operation method of the oxide supply device 9 will be described. First, as shown in FIG. 2, in the water-cooled slag 61, the production rate (wt%) of the filamentous slag contained in the water-cooled slag 61 changes according to the basicity (wt% / wt%) of the ash content of the coal 41. . That is, when the basicity of the ash content of the coal 41 is lowered, the generation rate of the ring-like thread slag shown in FIG. 1A and the needle-like thread slag shown in FIG. This water-cooled slag has a tendency that the production rate of the thread-like slag is divided into a fiber form and a granulation at the boundary of 10 wt%, and the discharge rate of the water-cooled slag is stable if the production rate of the thread-like slag is 10 wt% or less. ing.

  For this reason, in this embodiment, the production | generation ratio of a filamentous slag is set to 10 wt% or less as a reference | standard for discharging | emitting the water-cooled slag 61 stably. Thereby, according to FIG. 2, it becomes possible to determine in advance the shape of the water-cooled slag using the basicity of the ash content of the coal 41 supplied to the gasification furnace 5 as a threshold value. That is, if the basicity of the ash of coal 41 is 6 wt% or more, most of the water-cooled slag 61 of the coal becomes granular granulated slag and the properties of the granulated slag become stronger, so that stable discharge of slag is possible. It becomes. On the other hand, if the CaO concentration in the ash of the coal 41 is less than 6 wt%, the water-cooled slag 61 of the coal is not crushed and mostly becomes thread-like slag, and the properties of the thread-like slag become stronger. This causes the branching section and the narrow section of the line 21 to be blocked, and the slag cannot be discharged stably.

Therefore, in this embodiment, the basicity of the ash content of the coal 41 is confirmed before the coal 41 is input to the gasification furnace 5. Here, the basicity of ash is the total weight ratio (wt%) of at least CaO, Fe ₂ O ₃ , MgO, MnO, Na ₂ O, and K ₂ O among basic oxides. It is a value divided by the total weight ratio (wt%) of SiO ₂ , Al ₂ O ₃ , P ₂ O ₅ , and TiO ₂ .

  FIG. 6 shows an example of a method for confirming and adjusting the basicity of the ash content of coal 41. First, in step S1, the composition of the ash content of the coal is analyzed either when the coal to be tested for the gasifier is received or at the planning stage for selecting the coal. When the result of the ash composition analysis of the analyzed coal comes out, in the subsequent step S2, it is evaluated whether or not the basicity of the ash content in the coal is 0.21 or more. As a result, if the basicity of the ash is 0.21 or more, it is determined in step S3 that it is not necessary to adjust the CaO concentration of the coal ash, and the coal is used as a raw coal without adding additives. Is done.

On the other hand, if the basicity of the ash is less than 0.21, the process proceeds to slap S4, and in order to adjust the basicity of the ash of the coal, either the basic oxide or the separately prepared coal for adjustment is added. Selected. This embodiment is applied when a basic oxide is selected. If a basic oxide is selected, it will progress to step S5 and a predetermined amount of basic oxide will be mixed with coal. As the basic oxide, a calcium compound such as calcium carbonate can be used in addition to any oxide (for example, Fe ₂ O ₃ or MgO) of the molecule of the formula (1).

  Subsequently, in step S6, the basicity of the ash content of the mixed powder in which the coal and the basic oxide are thus mixed is analyzed. As a result, if the basicity of the ash is 0.21 or more, the process proceeds to step S3, and this mixed powder is supplied to the gasifier as raw coal, and if the basicity of the ash is less than 0.21, the ash The adjustment with the basic oxide is repeated until the basicity of is 0.21 or more.

  In this embodiment, in FIG. 4, the basicity of the ash content of the coal 41 supplied to the pulverized coal supply device 7 is analyzed. If the basicity of the ash content is less than 0.21, the coal supply 41 from the oxide supply device 9. Is mixed with a basic oxide. The basic oxide is introduced into the pulverized coal supply line 39 through which the pulverized coal is conveyed through the oxide supply line 51, and is mixed with the pulverized coal to be mixed powder. The basic oxide is supplied so that the basicity of the ash content of the mixed powder is 0.21 or more. For example, the basicity of the ash content of the coal 41, the target basicity of the ash content of the coal 41, and the supply of the coal 41 The supply amount is set based on the amount. The supply amount of the coal 41 by the pulverized coal supply device 7 and the supply amount of the basic oxide by the oxide supply device 9 are the control devices not shown in the figure according to the set supply amount, etc. It is prepared by controlling with.

  Thus, by putting the mixed powder prepared so that the basicity of the ash content of the coal 41 is 0.21 or more into the gasification furnace 5, most of the molten slag 59 is crushed in the quench water 23 of the quench section 13. Most of the water-cooled slag 61 is granular granulated slag. That is, the generation ratio of the filamentous slag is suppressed to 10 wt% or less of the entire water-cooled slag.

  According to the present embodiment, even when the basicity of the ash content of the coal 41 is less than 0.21, the basicity of the gasifier 5 is always reduced to 0.00 by mixing the basic oxide with the coal 41. The mixed powder prepared to 21 or more is supplied. Therefore, by performing the operation of the gasification furnace 5 in this way, the generation rate of the filamentous slag with respect to the total water-cooled slag can be suppressed to 10 wt% or less, and the water-cooled slag can be continuously discharged. Continuous operation of the furnace can be achieved, and the reliability of the gasifier can be improved.

(Second Embodiment)
Next, a second embodiment to which the operation method of the gasification furnace of the present invention is applied will be specifically described with reference to the drawings. FIG. 7 shows a schematic configuration of the coal gasifier of the present embodiment. This coal gasifier differs from the first embodiment in that the oxide supply device 9 of FIG. 4 is an adjustment coal supply device 63. Note that this embodiment will be described with respect to differences from the first embodiment, and the description of the configuration common to the first embodiment will be omitted.

  The coal gasifier according to the present embodiment includes a gasifier 5, a pulverized coal supply device 7, and a preparation coal supply device 63. The adjustment coal supply device 63 includes a coal pulverizer 65, a pulverized coal hopper 67, a rotary feeder 68, and a distributor 69. The coal pulverizer 65, the pulverized coal hopper 67, the rotary feeder 68 and the distributor 69 are connected to each other via a pulverized coal supply line 71, and the pulverized coal supply line 71 is connected to the pulverized coal supply line 39.

  Coal crusher 65 is supplied with adjustment coal 73 and air 75. The pulverized coal pulverized to a predetermined size by the coal pulverizer 65 is air-flowed to the pulverized coal hopper 67 via the pulverized coal supply line 71 and temporarily stored.

  This embodiment is applied when a basic oxide is selected in step S4 of FIG. If a basic oxide is selected in step S4, it will progress to step S7 and a predetermined amount of adjustment coal will be mixed with coal. Coal having a basicity of 0.21 or more is used for the preparation coal. Subsequently, in step S8, the basicity of the ash content of the mixed powder in which the coal and the coal for preparation are mixed in this way is analyzed. As a result, if the basicity of the ash is 0.21 or more, the process proceeds to step S3, and this mixed coal is supplied to the gasifier 5, and if the basicity of the ash is less than 0.21, The adjustment with the coal for preparation is repeated until the degree becomes 0.21 or more. In addition, the coal for preparation may be the same type of coal as the coal whose basicity is adjusted, or may be a different type of coal.

  In FIG. 7, the basicity of the ash content of the coal 41 supplied to the pulverized coal supply device 7 is analyzed. If the basicity of the ash content is less than 0.21, the preparation coal is supplied from the preparation coal supply device 63 to the coal 41. 73 is mixed. Preparation coal 73 is introduced into pulverized coal supply line 39 through pulverized coal supply line 71 and mixed with coal 41 to form mixed coal. The coal for preparation 73 is supplied so that the basicity of the ash content of the mixed coal becomes 0.21 or more. For example, the basicity of the ash content of the coal 41, the basicity of the ash content of the coal for preparation 73, the ash content of the coal 41 The supply amount is set based on the target basicity and the supply amount of coal 41. The supply amount of the coal 41 by the pulverized coal supply device 7 and the supply amount of the adjustment coal 73 by the preparation coal supply device 63 are the control devices (not shown) of the rotational speeds of the rotary feeders 36 and 68 according to the set supply amount. It is prepared by controlling with.

  According to the present embodiment, even if the basicity of the ash content of the coal 41 is less than 0.21, the basicity of the gasification furnace 5 is always reduced to 0.00 by mixing the adjustment coal 73 with the coal 41. The mixed coal prepared to 21 or more is supplied. Therefore, by operating the gasification furnace 5 in this way, the production rate of the filamentous slag with respect to the total water-cooled slag can be suppressed to 10 wt% or less, and the water-cooled slag can be continuously discharged as in the first embodiment. Therefore, continuous operation of the gasifier can be achieved, and the reliability of the gasifier can be improved.

  In the first and second embodiments, the example in which the basicity of the mixed powder and the ash content of the mixed coal supplied to the gasifier is adjusted to 0.21 or more has been described. If too much basic oxide is used, the melting temperature of the ash may increase. In this case, the furnace temperature must be very high in order to increase the gasification of coal and the fluidity of molten slag. Therefore, it is preferable to adjust the basicity of ash in the range of 0.21 to 1.3 from the viewpoint of equipment life and equipment maintenance.

(Third embodiment)
Next, a third embodiment to which the operation method of the gasification furnace of the present invention is applied will be specifically described with reference to the drawings. Although this embodiment is common to the first embodiment in that the coal gasifier of FIG. 4 is used, in addition to the basicity of the ash content of the coal 41 supplied to the gasification furnace 5, the CaO content of the coal 41 is CaO. This is different from the first embodiment in that the density is adjusted. In addition, this embodiment demonstrates only a different point from 1st Embodiment, and abbreviate | omits description about the structure which is common in 1st Embodiment.

  FIG. 8 shows a method for confirming and adjusting the coal 41 according to the present embodiment. First, in step S11, the composition of the ash content is analyzed either when the coal to be used for the gasification furnace 5 is received or at the planning stage for selecting the coal. If the result of the composition analysis of the analyzed coal comes out, in the following step S12, the basicity of coal ash and the CaO concentration of the ash will be evaluated. As a result, if the basicity is 0.21 or more and the CaO concentration is 6 wt% or more, the process proceeds to step S13, and the coal is used as raw coal without adding an additive.

  On the other hand, when the basicity is 0.21 or more and the CaO concentration does not satisfy the condition of 6 wt% or more, the process proceeds to step S14, and either an additive of calcium carbonate or separately prepared coal is selected. Is done. This embodiment is applied when calcium carbonate is selected. When calcium carbonate is selected, the process proceeds to step S15, and a predetermined amount of calcium carbonate is mixed with coal so as to satisfy the conditions of basicity and CaO concentration.

  In subsequent step S16, the basicity and CaO concentration of the ash content of the mixed powder in which coal and calcium carbonate are mixed are analyzed. As a result, if the basicity is 0.21 or more and the condition that the CaO concentration is 6 wt% or more is satisfied, the process proceeds to step S13, and the mixed powder of coal 41 and calcium carbonate is fed to the gasifier as raw coal. Supplied. On the other hand, when the basicity is 0.21 or more and the condition that the CaO concentration is 6 wt% or more is not satisfied, the adjustment is repeated until this condition is satisfied.

  In the present embodiment, in the coal gasifier of FIG. 4, calcium carbonate is stored in the oxide hopper 47 of the oxide supply device 9 instead of the basic oxide. And when the basicity of the ash content of the coal 41 is 0.21 or more and the CaO concentration does not satisfy the condition of 6 wt% or more, the calcium carbonate supplied from the oxide supply device 9 is mixed with the coal 41. The The supply amount of calcium carbonate is set so that the basicity of the ash of the mixed powder after mixing with the coal 41 is 0.21 and the CaO concentration is 6 wt% or more. The supply amount of the coal 41 by the pulverized coal supply device 7 and the supply amount of the adjustment coal 73 by the oxide supply device 9 are the same as those of the rotary feeders 36 and 48 according to the set supply amount, as in the first embodiment. It is adjusted by controlling the rotation speed.

  According to this embodiment, even if the basicity of the ash content of the coal 41 is 0.21 or more and the CaO concentration does not satisfy the condition of 6 wt% or more, the coal 41 is always gasified by mixing the calcium carbonate with the coal 41. The furnace 5 is supplied with the mixed powder prepared so that the basicity of ash is 0.21 and the CaO concentration is 6 wt% or more. By performing the operation of the gasification furnace 5 in this way, compared to the first embodiment, the production rate of the filamentous slag with respect to the total water-cooled slag can be further stabilized in a low state of 10 wt% or less. Slag discharge can be further stabilized, continuous operation of the gasifier can be achieved, and the reliability of the gasifier can be improved.

  In the present embodiment, an example in which calcium carbonate is used as an additive for adjusting the basicity and CaO concentration of the ash content of coal 41 has been described. However, the present invention is not limited to this example. For example, calcium hydroxide or CaO is used. Other calcium compounds may be used such as substances that contain them.

(Fourth embodiment)
Next, a fourth embodiment to which the operation method of the gasification furnace of the present invention is applied will be specifically described with reference to the drawings. This embodiment is common to the second embodiment in that the coal gasifier of FIG. 7 is used. However, in addition to the basicity of the ash content of the coal 41 supplied to the gasifier, the ash content of the coal 41 is used. The second embodiment is different from the second embodiment in that the CaO concentration is adjusted. Note that this embodiment will be described only with respect to differences from the second embodiment, and description of the configuration that is common to the second embodiment will be omitted.

  This embodiment is applied when adjustment coal is selected in step S14 of FIG. That is, when the basicity of the ash content of the coal 41 is 0.21 or more and the CaO concentration does not satisfy the condition of 6 wt% or more, the preparation coal supplied from the preparation coal supply device 63 in FIG. 73 is mixed with the coal 41. The supply amount of the adjustment coal 73 is set so that the basicity of the ash of the mixed coal after mixing with the coal 41 is 0.21 or more and the CaO concentration is 6 wt% or more.

  According to this embodiment, even if the basicity of the ash content of the coal 41 is 0.21 or more and the CaO concentration does not satisfy the condition of 6 wt% or more, by mixing the adjustment coal 73 with the coal 41, The gasification furnace 5 is always supplied with a mixed coal having an ash content of 0.21 and a CaO concentration of 6 wt% or more. By performing the operation of the gasification furnace 5 in this manner, the generation rate of the filamentous slag with respect to the total water-cooled slag can be further stabilized in a low state of 10 wt% or less as compared with the second embodiment. Similarly to the embodiment, the discharge of the granulated slag can be further stabilized, the continuous operation of the gasifier can be achieved, and the reliability of the gasifier can be improved.

  In the third and fourth embodiments, an example of adjusting the CaO concentration to 6 wt% or more in addition to adjusting the basicity of the mixed powder and the ash content of the mixed coal to be introduced into the gasification furnace to 0.21 or more. However, depending on the ash composition of coal, when the CaO concentration increases, the melting temperature of the ash may increase. In this case, the furnace temperature must be very high in order to increase the gasification of coal and the fluidity of molten slag. Therefore, from the viewpoint of equipment life and equipment maintenance, it is preferable to adjust the CaO concentration of ash to a range of 6 wt% or more and 40 wt% or less. Furthermore, if the amount of additives such as calcium carbonate and adjustment coal is reduced, an economic effect can be expected. Therefore, the CaO concentration in the ash is more preferably adjusted to a range of 6 wt% or more and less than 8 wt%. Good.

  Moreover, in the 1st-4th embodiment mentioned above, although the additives, such as a basic oxide and adjustment coal, were introduce | transduced into the pulverized coal supply line 39 and the coal 41 was shown, these additions were shown. As a method of mixing the agent with the coal 41, for example, an additive may be mixed with the coal 41 in advance at the mountain where the coal 41 is stored to adjust the basicity or CaO concentration of the ash of the coal 41, An additive may be introduced into the gasification unit 15 from a burner separately installed in the gasification furnace 5, and the basicity of ash and the CaO concentration may be adjusted in the gasification unit 15.

In the first to fourth embodiments described above, the basicity is determined based on the total weight ratio (wt%) of at least CaO, Fe ₂ O ₃ , MgO, MnO, Na ₂ O, and K ₂ O among basic oxides. ) Is divided by the total weight ratio (wt%) of at least SiO ₂ , Al ₂ O ₃ , P ₂ O ₅ , and TiO ₂ among the acidic oxides. For example, when determining the basicity of coal, If it is possible to determine the total weight ratio (wt%) of the basic oxide in the ash and the total weight ratio (wt%) of the acidic oxide, the total weight ratio (wt%) of the basic oxide It is preferable to use a value divided by the total weight ratio (wt%) of the acidic oxide.

DESCRIPTION OF SYMBOLS 5 Gasification furnace 7 Pulverized coal supply apparatus 9 Oxide supply apparatus 13 Quench part 15 Gasification part 19 Slag tap 21 Slag discharge line 23 Quench water 33 Coal crusher 39 Pulverized coal supply line 59 Molten slag 61 Water-cooled slag 63 Coal for adjustment Supply device

Claims (6)

A quenching section for storing water in a lower part of a gasification furnace for gasifying coal is provided, and the gasification residue of the coal is melted into molten slag in the gasification furnace, and the molten slag is put into the water of the quenching section. In the operation method of the gasifier for separating the water-cooled slag obtained by flowing down from the water,
In order to make the production rate of the filamentous slag contained in the water-cooled slag equal to or less than the set proportion of the weight ratio of the total water-cooled slag, the basicity of the coal ash obtained by the following formula is 0.21 or more. How to operate the gasifier.
Basicity (wt% / wt%) = total weight ratio (wt%) of at least CaO, Fe ₂ O ₃ , MgO, MnO, Na ₂ O, K ₂ O of basic oxide / at least SiO of acidic oxide ₂ , Al ₂ O ₃ , P ₂ O ₅ , TiO ₂ total weight ratio (wt%)   When the basicity of the ash content of the coal is less than 0.21, the basic oxide is mixed with the coal, and the basicity of the ash content of the mixed powder after mixing is adjusted to 0.21 or more. The method for operating a gasifier according to claim 1, wherein the gasifier is charged into a gasifier.   When the basicity of the ash content of the coal is less than 0.21, the adjustment coal is mixed with the coal and the basicity of the ash content of the mixed coal after mixing is adjusted to 0.21 or more. The operation method of the gasifier according to claim 1, wherein the operation is performed in a gasifier.   The operation method of a gasifier according to claim 1, wherein the CaO concentration of the coal ash is 6 wt% or more.   When the CaO concentration of the coal ash is less than 6 wt%, the calcium compound is mixed with the coal, the CaO concentration of the mixed powder after mixing is adjusted to 6 wt% or more, and the mixed powder is sent to the gasifier. The operation method of the gasifier according to claim 4, wherein the operation is performed.   When the CaO concentration of the coal ash is less than 6 wt%, the coal for adjustment is mixed with this coal, and the CaO concentration of the mixed coal after mixing is adjusted to 6 wt% or more. The operation method of the gasifier according to claim 4, wherein the operation is performed.

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