JP3462608B2 - Coal gasifier - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a combustor for burning coal to generate high-temperature gas, and a reducer for gasifying coal with the high-temperature gas generated by the combustor. The present invention relates to an operation method of a coal gasifier and a coal gasifier. 2. Description of the Related Art In a coal gasifier, a flux is injected together with coal into the furnace to lower the melting point of coal combustion ash and improve the ash dischargeability of the combustor. The conventional method will be described with reference to FIG. In FIG. 4, reference numeral 1 denotes a reducer. In the reducer 1, coal is gasified by a high-temperature gas generated by burning coal in a lower combustor 2. [0003] Reference numeral 6 denotes a coal mill, which pulverizes and mixes the supplied coal 7 and flux 8 and supplies them to the pulverized coal hopper 3 for the reducer and the pulverized coal hopper 5 for the combustor. Reference numeral 9 denotes a char recovery cyclone for recovering the char from the coal gasified gas discharged from the reducer 1, and the recovered char is recycled from the recycle chahopper 4 to the combustor 2. [0004] The coal gasifier of FIG. 4 is configured as described above, and the flux 8 supplied to the coal gasifier is supplied to the coal mill 6 and mixed with pulverized coal in the coal mill 6. After passing through hoppers 3 and 5, they are put into the reducer 1 and the combustor 2. [0005] In a conventional coal gasifier, a flux for lowering the melting point of coal ash is supplied to both the reducer 1 and the combustor 2 as described above. By introducing the flux, the melting and discharging of the ash in the combustor 2 is improved, but the melting point of the ash is also reduced in the reducer 1 and the area where the ash changes from a solid phase to a liquid phase is expanded. This is shown in FIG. FIG. 3 shows the relationship between the distribution of the gas temperature in the axial distance of the coal gasifier and the area where the ash adheres frequently. The transition temperature at which the coal ash changes from a solid phase to a liquid phase when no flux is added to the coal gasifier is b. Correspondingly, a region where much ash is deposited in the coal gasifier is C. [0007] On the other hand, when flux is added to the coal gasifier, the transition temperature of the ash decreases to a, and the area where the ash adheres much in the coal gasifier expands to d in response. . The temperature e at the bottom of the furnace is determined by adding flux.
Is the temperature of the ash flow zone and the ash discharge is stable. In the region where the ash changes from the solid phase to the liquid phase as shown in FIG.
Since the ash easily adheres to the wall surface in the coal gasification furnace, a large amount of ash adheres to the entire furnace wall surface, causing a problem. [0008] The present invention relates to a coal gasification furnace in which a flux is added to lower the melting point of ash and improve its dischargeability.
The task is to provide a furnace . SUMMARY OF THE INVENTION The present invention relates to a coal gasifier having a combustor for burning coal to generate a high-temperature gas, and a reducer for gasifying coal with the high-temperature gas generated by the combustor. In order to solve the above-mentioned problem in the furnace , a coal supply line to the combustor,
Recycler supply line to the star, and the reducer
Of the coal supply line to the
Providing coal gasifier connected the flux supply line made from a sheet line and recycling tea supply line only alkaline earth series metal. [0010] In the reductor section of the coal gasifier, the temperature of the high-temperature gas from the combustor rapidly drops at an early stage due to the mixing of the coal introduced by the reducer and the pyrolysis reaction of volatiles in the coal, and thereafter the gasification reaction. Gently lowers the temperature. FIG. 2 shows this state. FIG. 2 shows FIG.
Similarly to the above, the relationship between the axial distance of the coal gasifier and the gas temperature is shown. It can be seen that the gas temperature decreases at the reducer. By adding a flux into the coal gasifier in such a state, the melting point of the coal ash is lowered by about 50 ° C. to 200 ° C., depending on the type of coal. That is, the transition temperature range of coal ash due to the addition of flux shifts to a temperature range in which the gas temperature gradually decreases, and as a result, the area where ash adheres becomes wider than before, causing a problem. As you did. In the present invention, by adding the flux to part or all of the fuel injected into the combustor,
Although the melting point of the ash in the combustor section is lowered, the flux is not added to the coal in the reducer section, thereby reducing the area where the ash adheres much in the reducer section without impairing the ash discharge performance in the combustor section. That is, in FIG. 2, in the case of the conventional method in which the flux is supplied to both the reducer and the combustor, the area where much ash adheres is d, but the coal gas of the present invention in which the flux is not supplied to the reducer is used. For furnaces ,
The area where the ash adheres is reduced to f. On the other hand, the temperature g of the ash at the bottom of the furnace is in the fluidized region due to the introduction of the flux into the combustor, and the discharge of the ash is stabilized. [0015] The coal gasification furnace according to the present invention described above
The coal feed line to the combustor, recycle tea supply line to the combustor, and among the coal supply lines to the reductor, an alkali earth-based metal only recycle tea supply line to the coal supply lines and combustor to the combustor It can be easily implemented by the coal gasifier of the present invention connected to a flux supply line. According to the above-described coal gasifier of the present invention, flux is added only to the combuster so that the ash can be melted and discharged while reducing the ash adhesion area in the coal gasifier. It can be performed stably. [0018] EXAMPLES The following specifically described based on the embodiment shown in FIG. 1 for coal gasifier that by the present invention. In addition,
In the embodiment of FIG. 1, the same components as those of the conventional apparatus shown in FIG. 4 are denoted by the same reference numerals for the sake of simplicity of description, and redundant description thereof will be omitted. In the coal gasifier according to the present embodiment, as shown in FIG. 1, fuel is supplied to the combustor unit by supplying flux through the line of the recycle cha hopper 4 to the combustor and the pulverized coal hopper 5 for the combustor. Flux was supplied only to In this case, the flux is an alkaline earth metal, specifically, calcium, potassium, iron, N
a etc. can be input. In this embodiment, limestone (C
aCO ₃ ) is injected into a combustion field at about 900 ° C. to oxidize
The flux was CaO (calcium oxide). Although the melting point of the ash depends on the amount of the flux contained in the combustion ash, the melting point of the ash was lowered at about 200 ° C. in this example. Although the present invention has been described in detail with reference to the illustrated embodiments, the present invention is not limited to these embodiments, and various modifications may be made within the scope of the present invention as set forth in the appended claims. Needless to say, For example, in the above-described embodiment, the flux 8 is added to both the recycle cha hopper 4 for the combustor and the pulverized coal hopper 5 for the combustor, but the flux 8 is added to only one of the two. The flux may be supplied. As described above, according to the present invention, the ash discharge at the bottom of the gasification furnace is stabilized by introducing the flux composed of the alkaline earth metal into only the combustor, and the flow to the reducer is reduced. By not supplying flux to the pulverized coal to be charged, the area where ash was attached could be made smaller than in the conventional method.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a flux charging system according to an embodiment of the present invention. FIG. 2 is a diagram showing a state of a region where slag adheres much in a furnace according to the present invention and a region where slag adheres much in a conventional method. FIG. 3 is a diagram showing a relationship between a gas temperature distribution in a coal gasifier and a region where a large amount of ash adheres. FIG. 4 is a configuration diagram of a conventional flux input system in a coal gasifier. [Description of Signs] 1 Reductor 2 Combustor 3 Pulverized coal hopper for reductor 4 Recycled char hopper 5 Pulverized coal hopper for combustor 6 Coal mill 7 Flux input device

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tomoki Koyama 5-717-1 Fukahoricho, Nagasaki-shi, Nagasaki Research Laboratory, Mitsubishi Heavy Industries, Ltd. (56) References JP-A-4-136093 (JP, A) 60-104188 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C10J 3/46

Claims (1)

(1) A coal gasifier having a combustor for burning supplied coal to generate a high-temperature gas, and a reducer for gasifying coal with the high-temperature gas generated by the combustor. In, the coal supply line to the combustor, the recycler supply line to the combustor, and the coal supply line to the reducer, from the alkaline earth metal only to the coal supply line to the combustor and the recycler supply line A coal gasifier characterized by connecting a flux supply line.