AU2011241999B2

AU2011241999B2 - Coal gasifier

Info

Publication number: AU2011241999B2
Application number: AU2011241999A
Authority: AU
Inventors: Masumi Itonaga; Katsushi Kosuge; Hiroyuki Kozuru; Yasuki Namiki; Yoshiyuki Saiwai; Suguru Takeda; Hideaki Yabe
Original assignee: Nippon Steel and Sumikin Engineering Co Ltd
Current assignee: Nippon Steel Engineering Co Ltd
Priority date: 2010-04-16
Filing date: 2011-04-11
Publication date: 2013-12-19
Anticipated expiration: 2031-04-11
Also published as: CN104479748B; CN102892870A; JP5552157B2; JPWO2011129302A1; WO2011129302A1; CN104479748A; AU2011241999A1

Abstract

Disclosed is a coal gasification furnace comprising: a reaction vessel (12) formed in a cylindrical shape extending upwards, equipped with an outlet at the upper end thereof; and a plurality of cylindrical burner units (17) disposed on a reference plane (P1) parallel to a horizontal plane and lower than the outlet, and in a circumferential direction with gaps left therebetween on an inside surface of the reaction vessel, which supply coal and an oxidising agent to the inside of the reaction vessel; and coal is burned inside the reaction vessel to produce at least hydrogen gas and carbon monoxide gas. When seen from above, the axes (C1) of the burners are oriented in the same direction as and touch an imaginary circle centred on a central axis with a diameter less than the inside diameter of the reaction vessel, where the axes are parallel to a horizontal plane or where the tips of the burner units are oriented downwards.

Description

1 DESCRIPTION COAL GASIFIER 5 TECHNICAL FIELD [0001] This present invention relates to a coal gasifier in which coal is gasified with an oxidizing agent such as oxygen gas or water vapor and which produces combustible gas. Priority is claimed on Japanese Patent Application No. 2010-095496, filed April 10 16, 2010, the content of which is incorporated herein by reference. BACKGROUND ART [0002] For example, in the related art, as a gasification furnace (a coal gasifier) which 15 produces combustible gas from pulverized coal or the like, the gasification furnace disclosed in Patent Document I is known. In this gasification furnace, four combustor burners in a plan view are disposed at equal distances on a circumference in a predetermined plane in a pressure vessel (reaction vessel). In addition, two sets of combustor burners, which are disposed at symmetrical positions while interposing a 20 center axis of the circumference, are disposed so as to face each other. [0003] The combustor burner includes a light oil burner for starting the gasification furnace that is provided in the center portion and an air nozzle, a char nozzle, a coal nozzle for fuel, and a secondary air nozzle that are disposed in this order from the inner 25 side to the outer side concentrically with the light oil burner.

2 After being rotated in the respective nozzles, air, char (non-gasification coal residues or pyrolysis residues), and the coal for fuel are fired by the light oil burner and ejected into the pressure vessel. Citation List Patent Document [0004] [Patent Document 1] Japanese Patent No. 3595404 [0005] However, in the gasification furnace disclosed in Patent Document 1, when the gas or the like that is rotated and flows from each combustor burner is ejected, since the combustor burners are disposed at positions which face each other, the gases or the like that are ejected from the combustor burners collide, and there is a problem in that a flow of the gas or the like in the gasification furnace is not stable. In addition, the inner circumferential surface of the gasification furnace is exposed to a high temperature environment due to partial oxidation (hereinafter, referred to as "gasification") of the coal. However, if slag having a constant thickness is not stably attached to an inner circumferential surface of the gasification furnace, heat loss increases, which leads to a deterioration in performance and there is a concern that the inner circumferential surface is subjected to the influence of the heat and may be damaged. Moreover, the gas or the like which is generated due to the gasification rises in the gasification furnace. However, if there is nonuniformity in the rising flow of the gas or the like in the gasification furnace, carbon (char) in the coal flows out of the gasification furnace before being sufficiently subjected to the gasification reaction, and a reaction rate (a rate at which the carbon in the coal is converted to gas) may be decreased.

3 Object of the Invention [0006] It is the object of the present invention to substantially overcome or at least ameliorate one or more of the foregoing disadvantages. Summary of the Invention [0007] A coal gasifier disclosed in the present application includes a reaction vessel which is formed in a cylindrical shape which extends upward and in which an outlet is provided on the upper end side, and a plurality of cylindrical burner portions that are provided with an interval in the circumferential direction on an inner circumferential surface of the reaction vessel in a reference plane that is parallel to a horizontal surface and is positioned downward from the outlet and that supplies coal and oxidizing agent to the reaction vessel, wherein at least hydrogen gas and carbon monoxide gas are produced by gasifying the coal in the reaction vessel, and when each of the burner portions is viewed from above, each burner portion is disposed so that an axis line thereof contacts around the same direction on a virtual circle that has a diameter smaller than an inner diameter of the reaction vessel and has the center axis line as the center thereof, and the axis line thereof is parallel to the horizontal surface or is inclined downward as the axis line approaches the tip of the burner portion. That is, in the present invention, a coal gasifier in which at least hydrogen gas and carbon monoxide gas are produced by gasifying coal in a reaction vessel includes: a reaction vessel that is formed in a cylindrical shape that extends upward; an outlet that is provided on the upper end side of the reaction vessel; and a plurality of cylindrical burner portions that supply the coal and oxidizing agent to the reaction vessel, wherein the plurality of burner portions are provided with an interval toward the circumferential direction of an inner circumferential surface of the reaction vessel on a reference plane that is parallel to a horizontal surface positioned downward from the outlet, when the reaction vessel is viewed from above, each of the burner portions is disposed so that an axis line 4 of each burner portion contacts around the same direction on a virtual circle that has a diameter smaller than an inner diameter of the reaction vessel that has a center axis line of the reaction vessel as the center, and the burner portion is disposed so that the axis line of the burner portion is parallel to the horizontal surface or is inclined downward as the axis line approaches the tip of the burner portion. Moreover, in the coal gasifier, when mass flow rates of the coal and the oxidizing agent that are supplied to the reaction vessel from each of the burner portions are represented by ml (kg/s) and m2 (kg/s) respectively, and flow speeds of the coal and the oxidizing agent in each of the burner portions are represented by VI (m/s) and V2 (m/s) respectively, it is more preferable that a mean flow speed Va (m/s) according to Equation (1) be set to 10 (m/s) or more and 50 (m/s) or less. Va=(ml x V1+ m2 x V2) /(ml + m2) ... (1) [0008] According to an embodiment of this invention, when the burner portion supplies the coal and the oxidizing agent to the cylindrical reaction vessel, a flow of fluid that rotates around the center axis line of the reaction vessel can be generated. Thereby, the flow of fluid in the vicinity of the inner circumferential surface of the reaction vessel is stable regardless of the position in the circumferential direction, and the thickness of a molten slag which is generated due to the gasification of the coal and is attached to the inner circumferential surface of the reaction vessel can be substantially uniform. In addition, the burner portion is disposed so that the axis line thereof is parallel to the horizontal surface or is inclined downward as the axis line approaches the tip of the burner portion. Since the coal, which is gasified and expanded and rises while rotating in the reaction vessel, temporarily flows horizontally or toward the lower portion from the burner portion, the time for which the coal flows in the reaction vessel is increased, and the coal can be sufficiently gasified in the reaction vessel before being discharged from the outlet.

5 Further, due to the fact that the mean flow speed Va is 50 (m/s) or less, the peeling away of the slag, which is attached to the inner circumferential surface of the reaction vessel, from the inner circumferential surface is suppressed, and thereby, the heat loss that is transmitted from the reaction vessel to the outside can be decreased. In addition, due to the fact that the mean flow speed Va is 10 (m/s) or more, the transportation of the coal through the oxidizing agent can be stably performed in the burner portions. [0009] In addition, in the coal gasifier, it is more preferable that the burner portions be disposed at equal intervals around the center axis line of the reaction vessel. According to this feature, the flows of the coal and the oxidizing agent which are supplied from the burner portions and the fluid which includes the gas generated due to the combustion of the coal can be further stabilized in the reaction vessel. [0010] Moreover, in the coal gasifier, it is more preferable that a ratio of the diameter of the virtual circle with respect to the inner diameter of the reaction vessel be set to 1/10 or more and 1/3 or less. According to this feature, due to the fact that the ratio (hereinafter, also referred to as a "diameter ratio") of the diameter of the virtual circle with respect to the inner diameter of the reaction vessel is 1/3 or less, the speed gradient of the fluid in the inner circumferential surface of the reaction vessel is decreased and peeling away of the slag, which is attached to the inner circumferential surface of the reaction vessel, from the inner circumferential surface is suppressed. Therefore, a decrease in performance due to an increase of heat loss or damage to the inner circumferential surface, which are generated due to exposure of the inner circumferential surface of the reaction vessel to high temperature, can be prevented. Moreover, due to the fact that the diameter ratio is 1/10 or more, the coal, the oxidizing agent, and the like supplied from the burner portions are prevented from direct colliding, the flow that 6 rotates around the center axis line of the reaction vessel is securely generated, the gasification reaction time is lengthened, and the reaction rate can be improved. Paragraph [0011] has been intentionally deleted. [0012] Moreover, in the coal gasifier, it is more preferable that an angle of the axis line of each of the burner portions with respect to the horizontal surface be set to 00 or more and 100 or less. According to this feature, due to the fact that the angle 0 is 0* or more and 10* or less, since the coal particles which are blown from the burner portions can be present at a high temperature field in the vicinity of the burner portion for a long time, a gasification reaction of char is promoted, and the reaction rate can be increased. [0013] In addition, in the coal gasifier, similar to the burner portions, it is more preferable that a char burner be disposed on a second reference plane parallel to the reference plane immediately above the burner portions in the reaction vessel. According to this feature, since unreacted char that is recovered from the char burner of the reaction vessel is recycled to the coal gasifier and is subjected to a gasification reaction, the gasification reaction rate of carbon in the coal can be 99% or more. [0014] According to the coal gasifier in an embodiment of the present invention, coal sufficiently reacts in a compact reaction vessel and slag can be stably attached to the inner circumferential surface of the reaction vessel.

7 Brief Description of the Drawings [0015] FIG. 1 is a block diagram of a coal gasification synthesis gas manufacturing system in which a coal gasifier of an embodiment of the present invention is used. FIG. 2 is a longitudinal cross-sectional view of a main portion of the coal gasifier. FIG. 3 is a plan cross-sectional view taken along a line A-A in FIG. 2.

8 FIG 4 is a view showing flow speed distribution in a reference plane of FIG 3. FIG. 5 is a view showing a relationship between a heat loss ratio and a reaction rate with respect to a diameter ratio in a partial oxidation portion of the coal gasifier. FIG 6 is a view showing the relationship of the heat loss ratio with respect to the 5 mean flow speed of coal and oxidizing agent in the coal gasifier. BEST MODE FOR CARRYING OUT THE INVENTION [0016] Hereinafter, an embodiment of a coal gasifier according to the present invention 10 is described with reference to FIGS. 1 to 6. The coal gasifier is used incorporated in a portion of a coal gasification system, and is an apparatus in which at least hydrogen gas and carbon monoxide gas are produced by combusting coal in the inner portion of the furnace. As shown in FIG 1, a coal gasification synthesis gas manufacturing system I is 15 plant equipment in which a synthesis gas composed primarily of hydrogen gas and carbon monoxide gas is produced using coal as a raw material. The produced synthesis gas is supplied to a chemosynthetic facility or the like as a raw material, and finally, methane, methanol, ammonia, and the like can be produced. The coal gasification synthesis gas manufacturing system 1 includes coal 20 pulverizing and drying equipment 2, coal supplying equipment 3, a coal gasifier 4 of the present embodiment, heat recovery equipment 5, char recovery equipment 6, shift reaction equipment 7, gas purification unit 8, and air separation equipment 9. [0017] Generally, the outer diameter of coal is not uniform, and according to the kind 25 thereof coal may contain more than a desired value of water. Therefore, first, in the coal 9 pulverizing and drying equipment 2, coal is pulverized so that approximately 75% is 200 mesh or less and a mean particle diameter is approximately 30 to 60 (gm), and the coal is dried to a predetermined water content, preferably, a total amount of water of 10% or less. Thereafter, the coal is supplied to the coal supplying equipment 3. In addition, the coal 5 is moved in a sealed space from the coal pulverizing and drying equipment 2 to the coal gasifier 4 so that the water content of the dried coal is not changed. Subsequently, in order to supply the coal to the coal gasifier 4, the pressure of the coal is increased to a predetermined pressure in the coal supplying equipment 3 due to a carrier gas or the like, thereafter, a predetermined weight of the coal is quantitatively 10 supplied to the coal gasifier 4 due to airflow transportation. An operation pressure of the coal gasifier is not particularly limited. However, from the viewpoints of improving reaction efficiency due to compactification of the gasification furnace and decreasing equipment and utilities costs, it is preferable that the operation pressure be 2 MPaG or more and 5 MIPaG or less. 15 Meanwhile, in the air separation equipment 9, air is compressed and is liquefied, and dried oxygen gas, nitrogen gas, and the like are separated from the air that becomes liquid due to the difference of boiling points. The oxygen gas that is separated through the air separation equipment 9 is supplied to the coal gasifier 4 at a predetermined flow rate. 20 [0018] As shown in FIG 2, the coal gasifier 4 includes at least a partial oxidation portion (reaction vessel) 12 at the upper portion DI, and a preheating portion 15 is provided at the lower portion D2 of the partial oxidation portion 12. The partial oxidation portion 12 and the preheating portion 15 communicate with each 25 other in a vertical direction D.

10 [0019] As shown in FIGS. 2 and 3, the partial oxidation portion 12 is cylindrically formed of heat-resistant refractory or the like so as to extend in the vertical direction D, and eight burner portions 17a to 17h which are formed in a cylindrical shape which 5 extends along an axis line CI are provided on the inner circumferential surface of the partial oxidation portion 12 (hereinafter, when these burner portions 17a to 17h are shown without particular discrimination, these are collectively referred to as a "burner portions 17"). In addition, the number of the burner portions 17 that are provided in the partial 10 oxidation portion 12 is not limited, and there may be any numbers of the burner portions 17 if there are provided more than two burner portions 17. However, according to an increase in the dimensions of the partial oxidation portion 12, it is preferable that the number is increased to four, six, eight, and so on, and portions of an even number be provided. However, there are no problems if portions of an odd number are provided. 15 Eight burner portions 17 are provided on a reference plane P1 parallel to a horizontal surface, and are disposed at equal intervals around a center axis line C2 of the partial oxidation portion 12. [0020] As shown in FIG. 3, when the burner portions 17 are viewed from the upper 20 portion D1, the burner portions 17 are disposed so that the axis line C1 of the burner portion 17 contacts around the same direction F1 on a virtual circle E which has a diameter smaller than an inner diameter RI of the partial oxidation portion 12 and has the center axis line C2 as the center. Here, contacting around the same direction F1 means that the axis line Cl contacts around the direction F1 with respect to the virtual circle E 25 when it is assumed that the axis line C1 of each burner portion 17 extends from the tip of 11 the burner portion 17. In addition, the axis line CI of each burner portion 17 may be disposed so as to contact around a direction F2 which is a direction*opposite to the direction F1 on the virtual circle E. Moreover, a diameter ratio which is a ratio (the diameter R2 of the virtual circle 5 / the inner diameter RI of the reaction vessel) of the diameter R2 of the virtual circle with respect to the inner diameter RI of the partial oxidation portion 12 is set so as to be 1/10 or more and 1/3 or less. The diameter ratio is more preferably 1/5 or more and 3/10 or less. In addition, as shown in FIG. 2, an angle e of the axis line Cl of the burner 10 portion 17 with respect to the horizontal surface is set so as to be 00 or more and 100 or less. That is, the tip of the burner portion 17 is preferably inclined so as to be 0* or more and 100 or less with respect to the horizontal surface toward the lower portion of the partial oxidation portion 12, and is more preferably inclined so as to be 0* or more 15 and 20 or less. [0021] In the coal pulverizing and drying equipment 2, the pulverized and dried finely-powdered coal is supplied to each burner portion 17 at a predetermined flow rate from the coal supply portion 20. Oxygen gas that is separated in the air separation 20 equipment 9 and water vapor that is supplied from the heat recovery equipment 5 described below are supplied to each burner portion 17 at a predetermined flow rate from an oxidizing agent supply portion 21. When described in more detail, the mass flow rates of the coal and the oxidizing agent (oxygen gas and water vapor) that are supplied to the partial oxidation portion 12 12 from the burner portions 17 are represented by ml (kg/s) and m2 (kg/s) respectively, and the flow speeds of the coal and the oxidizing agent in the burner portions 17 are represented by VI (m/s) and V2 (m/s) respectively. At this time, the flow rates of the coal and oxidizing agent are regulated by the coal supply portion 20 and oxidizing agent 5 supply portion 21 so that the mean flow speed Va (m/s) according to the following Equation (2) is 10 (m/s) or more and 50 (m/s) or less. Va = (ml x VI + m2 x V2) / (m] + m2) ... (2) That is, the mean flow speed Va is a mean flow speed of the fluid that is discharged from a raw material ejection port of the burner portion 17. 10 However, the oxygen gas in the oxidizing agent is appropriately set at an oxygen to coal (oxygen/coal) weight ratio of 0.7 to 0.9, and the water vapor is appropriately set at a water vapor to coal (water vapor/ coal) weight ratio of 0.05 to 0.3 according to the kind of the coal or a planned operation temperature. Moreover, the flow speed VI (m/s) of the oxidizing agent in the burner portions 17 is the flow speed in a state where the 15 oxygen gas and the water vapor are mixed. The differences in the kind of the coal can be shown due to an industrial analysis value and an element analysis value of the coal, ash composition, and the like. In addition, the mean flow speed Va is more preferably 10 (m/s) or more and 30 (m/s) or less. 20 [0022] A cooling wall conduit 22 for cooling the partial oxidation portion 12 is disposed in the outer circumferential surface of the partial oxidation portion 12, and a pump 23 for flowing water or saturated water (boiler water) into the inner portion of the conduit is connected to the cooling wall conduit 22. The water and saturated water 25 which flow in the cooling wall conduit 22 may circulate through the cooling wall conduit 13 22, the water and saturated water are heated using the partial oxidation portion 12 as a boiler and become high temperature vapor, and thereafter, the water vapor may be recovered and used as steam. [0023] 5 The coal and oxidizing agent, which are pulverized and in which the pressure is increased, are supplied from the above-described burner portions 17 to the partial oxidation portion 12 at the mean flow speed Va. Since eight burner portions 17 are disposed as shown in FIG 3, at first, as shown FIG 2, the coal and the oxidizing agent that are supplied from the burner portions 17 are ejected downward or so as to flow on 10 the same horizontal surface while rotating around the center axis line C2 of the partial oxidation portion 12. The inner portion of the partial oxidation portion 12 is at a high temperature and pressure (for example, the temperature is 1,200'C or more and 1,800 0 C or less and the pressure is 2 MPa or more). The temperature of the coal is increased in this environment and the coal is subjected to thermal decomposition, char and volatile 15 gas including tar, water vapor, and the like are separated, the coal is gasified, and high temperature carbon monoxide gas, carbon dioxide gas, hydrogen gas, and slag (ash) are generated according to the following Chemical Equations (1) to (3). [0024] 2C + O2 -> 2CO .-. (1) 20 C + 0 2 -> C02 ... (2) C + H 2 0 -> CO + H 2 --- (3) [0025] At this time, flow speed distribution of the hydrogen gas, the carbon monoxide gas, and the like in each portion in the partial oxidation portion 12 is shown in FIG. 4. 25 FIG 4 shows a flow speed v with respect to positions in a direction r from the center axis 14 line C2 on the reference plane P2 that includes the center axis line C2 of the partial oxidation portion 12 shown in FIG 3. Here, the reference plane P2 is the surface which is perpendicular to the reference plane P1 parallel with the horizontal surface. In the partial oxidation portion 12, fluid such as the hydrogen gas or the carbon monoxide gas 5 rises while rotating in the same direction (for example, the direction Fl) from the center axis line C2 toward the radial direction (r direction). In FIG 4, the change (distribution) of the flow speed v of the fluid in the r direction in the position of a certain height of the reference plane P2 is shown. Here, the position of a certain height may be any place along the height direction of the partial oxidation portion 12, and it is preferable that the 10 position be above the burner portions 17a. In FIG. 4, the longitudinal axis represents the positions in the r direction with respect to the center axis line C2, and the vertical axis represents the flow speed v. Moreover, in actual fact, at the side in which the position in the r direction is positive (the burner portion 17a side with respect to the center axis line C2 in FIG. 3) and the side in which the position in the r direction is negative (the burner 15 portion 17e side with respect to the center axis line C2 in FIG. 3), the directions of the flow speed v are different from each other. However, FIG 4 shows only the size without considering the direction of the flow speed v. Moreover, in FIG. 4, the thickness of a slag (described below) that is attached to the inner circumferential surface of the partial oxidation portion 12 is not considered. 20 [0026] In FIG 4, the burner portions 17 are installed to the partial oxidation portion 12 so that the diameter ratio of the virtual circle with respect to the inner diameter of the partial oxidation portion (reaction vessel) 12 is 1/5 or more and 3/10 or less, and the model of the flow speed v when the mean flow speed Va is 10 (m/s) or more and 30 (m/s) 25 or less is shown by a solid line.

15 As shown by the solid line in FIG 4, the flow speed v is greatest in the vicinity of the position in which the position in the r direction which becomes the position on the axis line C1 of the burner portion 17c is R2/2 and in the vicinity of the position in which the position in the r direction which becomes the position on the axis line Cl of the 5 burner portion 17g is -R2/2. In addition, the flow speed v approaches 0 and the absolute value of the inclination (speed gradient) of the curve of the flow speed v is decreased in the position in which the position in the r direction which becomes the position on the inner circumferential surface of the partial oxidation portion 12 is Rl/2 and in the position in which the position in the r direction is -RI/2. 10 When it is assumed that the hydrogen gas, the carbon monoxide gas, and the like are Newton fluid, since a force (shearing force) with which the fluid peels away the slag becomes (pt (dv/dr)) which multiplies the speed gradient of the flow speed v of the fluid by a coefficient of viscosity p, it is found that the shearing force in this case is relatively small. 15 [0027] On the other hand, in Comparative Example in which the mean flow speed Va according to Equation (2) exceeds 50 (m/s), as shown by a dotted line in FIG 4, the position in which the flow speed v becomes the maximum value is not changed, and the maximum value of flow speed v increases. Therefore, the absolute value of the 20 inclination of the curve of the flow speed v increases, the shearing force that acts on the slag increases, and the slag is easily peeled away. In addition, with respect to the configuration of the partial oxidation portion 12 which shows the flow speed distribution of the fluid shown by the solid line, in Comparative Example in which the axis line C1 of the burner portion 17b is separated 25 from the center axis line C2 of the partial oxidation portion 12 and the diameter ratio 16 exceeds 1/3, the flow speed distribution of the fluid becomes distribution as shown by a two-dot chain line in FIG 4. That is, in this case also, the absolute value of the inclination of the curve of the flow speed v at the position, in which the position in the r direction which becomes the position of the inner circumferential surface of the partial 5 oxidation portion 12 is R1/2 and -RI/2, increases, the shearing force which acts on the slag increases, and thereby, the slag is easily peeled away. [0028] As shown in FIG 2, the gas, the slag, and the like which are generated in the partial oxidation portion 12 are moved to the outside in the diameter direction while 10 rotating around the center axis line C2 of the partial oxidation portion 12, the temperatures of the gas, the slag, and the like increase, and the gas, the slag, and the like expand. Thereby, the gas, the slag, and the like are subjected to a lifting force due to buoyancy and rise in the inner circumferential surface side of the partial oxidation portion 12. The slag that is generated in the partial oxidation portion 12 is melted. 15 However, a portion of the slag S is cooled on the inner circumferential surface of the partial oxidation portion 12 and is attached to the inner circumferential surface, and the remaining portion of the slag falls into a slag tap 24 that is provided at the lower portion D2 of the partial oxidation portion 12, flows out in the preheating portion 15, and is recovered. 20 In addition, the thicker the slag S that is attached to the inner circumferential surface of the partial oxidation portion 12, the greater the insulation effect due to the slag S, and thereby, the more the partial oxidation portion 12 is protected from high heat, and the quantity of heat (hereinafter, referred to as "heat loss") which is transmitted from the partial oxidation portion 12 to the water and the like in the cooling wall conduit 22 is 25 decreased.

17 [0029] Here, the heat loss will be described with reference to FIG 5. If the amount of heat loss when the diameter ratio is 1/3 is set to I (reference) and percentage with respect to the amount of heat loss of other conditions is given as a heat 5 loss ratio, the heat loss ratio (LI) is rapidly increased when the value of the diameter ratio exceeds 1/3. Therefore, the distance between the axis line C1 of the burner portion 17 and the inner circumferential surface of the partial oxidation portion 12 is decreased. That is, the fluid that is discharged from the burner portions 17 is easily directed to the inner circumferential surface not the center portion of the partial oxidation portion 12. 10 Accordingly, the slag that is attached to the inner circumferential surface of the partial oxidation portion 12 is easily peeled away. Moreover, since the diameter of the rotating flow in the inner portion of the partial oxidation portion 12 is rapidly decreased if the diameter ratio is less than 1/10, required reaction time cannot be secured, and a reaction rate (L2) is rapidly decreased. The reaction rate as used herein means percentage with 15 respect to the reaction rate of other conditions when the reaction rate when the diameter ratio is 1/3 is set to I (reference). Moreover, as shown in FIG. 6, if the value of the mean flow speed Va exceeds 50 (m/s), as described above, the slag is easily peeled away, and the heat loss ratio is rapidly increased. In addition, if the mean flow speed Va is less than 10 (m/s), the airflow 20 transportation of the coal from the coal supplying equipment 3 into the coal gasifier 4 through the burner portions 17 is unstable or cannot operate due to blockage, and the amount of the coal supplied to the partial oxidation portion 12 is changed. [0030] Moreover, as shown in FIG 1, the char is accompanied by high temperature 25 synthesis gas that is composed primarily of the hydrogen gas and the carbon monoxide 18 gas from above the coal gasifier 4 and is supplied to the heat recovery equipment 5. In the heat recovery equipment 5, heat exchange is generated between the synthesis gas that is transported from the coal gasifier 4 and the boiler water, and thereby, water vapor is produced. This water vapor is supplied to the above-mentioned coal 5 pulverizing and drying equipment 2 and the like in order to dry the coal or the like. The synthesis gas that is cooled in the heat recovery equipment 5 is supplied from the heat recovery equipment 5 to the char recovery equipment 6, and the char that is included in the synthesis gas is recovered at the char recovery equipment 6. Here, the recovered char can be used separately as a fuel or the like. However, the char is 10 recycled to the coal gasifier 4 and can be gasified. The synthesis gas that passes through the char recovery equipment 6 is supplied to the shift reaction equipment 7. In order to increase the percentage of the hydrogen gas with respect to the carbon monoxide gas in synthesis gas to a constant value, water vapor is supplied to the shift reaction equipment 7, and a shift reaction using the catalyst 15 shown in the following Chemical Equation (4) is performed. According to this shift reaction, the carbon monoxide gas is consumed, and thereby, the hydrogen gas is generated. [0031] CO + H 2 0 -+ CO 2 + H 2 ... (4) 20 [0032] The synthesis gas, in which the component is adjusted in the shift reaction equipment 7, is supplied to the gas purification unit 8, and gas and the like that includes carbon dioxide gas and sulfur contained in the synthesis gas as component are recovered, The synthesis gas that is purified through the gas purification unit 8 and is 25 produced is supplied to the chemosynthetic facility or the like, and thereby, methane, 19 methanol, ammonia, and the like are produced. [0033] As described above, in the coal gasifier 4 of the present embodiment, the burner portions 17 supply the coal and the oxidizing agent in the cylindrical reaction vessel 12, 5 and thereby, the flow which rotates around the center axis line C2 of the reaction vessel 12 can be generated. Therefore, the flow of fluid in the vicinity of the inner circumferential surface of the reaction vessel 12 is stable regardless of the position in the circumferential direction, and the thickness of the molten slag which is generated due to the gasification of the coal and is attached to the inner circumferential surface of the 10 reaction vessel 12 can be substantially uniform. In addition, the burner portions 17 is disposed so that the axis line C1 thereof is parallel to the horizontal surface or is inclined toward the lower portion D2 as the axis line approaches the tip of the burner portion. According to this configuration, the combusting coal, which is gasified and expanded and rises while rotating in the partial 15 oxidation portion 12, can temporarily flow horizontally or toward the lower portion D2 from the burner portions 17 before moving to the heat recovery equipment 5. Accordingly, since the coal particles which are blown from the burner portions 17 can be present at a high temperature field in the vicinity of the burner portion 17 for a long time and the time for which carbon (char) in the coal flows in the partial oxidation portion 12 20 can be increased, the gasification in the partial oxidation portion 12 can be sufficiently performed. [0034] Moreover, since the burner portions 17 are disposed at equal intervals around the center axis line C2 of the partial oxidation portion 12, the flows in the partial oxidation 25 portion 12 of the coal and the oxidizing agent which are supplied from the burner 20 portions 17 and the fluid which includes the gas generated due to the gasification of the coal can be further stabilized. In addition, the burner portion 17 is disposed so that the diameter ratio of the virtual circle with respect to the inner diameter of the reaction vessel is 1/10 or more and 5 1/3 or less. Due to the fact that the diameter ratio is 1/3 or less, the speed gradient of the fluid in the inner circumferential surface of the partial oxidation portion 12 is decreased, peeling away of the molten slag or the like, which is attached to the inner circumferential surface of the partial oxidation portion 12, from the inner circumferential surface is suppressed. Therefore, it is possible to prevent the inner circumferential 10 surface of the partial oxidation portion 12 from being exposed to high temperature and being damaged. Moreover, due to the fact that the diameter ratio is 1/10 or more, the coal, the oxidizing agent, and the like supplied from the burner portions 17 are prevented from directly colliding, the flow that rotates around the center axis line C2 of the partial oxidation portion 12 is securely generated, and it is possible to prevent the reaction rate 15 from being decreased. [0035] Moreover, due to the fact that the mean flow speed Va is 50 (m/s) or less, the peeling away of the slag, which is attached to the inner circumferential surface of the partial oxidation portion 12, from the inner circumferential surface is suppressed, and 20 thereby, the heat loss that is transmitted from the partial oxidation portion 12 to the outside can be decreased. On the other hand, due to the fact that the mean flow speed Va is 10 (m/s) or more, the transportation of the coal through the oxidizing agent can be stably performed in the burner portions 17. Moreover, due to the fact that the angle 0 of the axis line C1 of the burner 25 portion 17 with respect to the horizontal surface is 00 or more and 10 * or less, since the 21 coal particles which are blown from the burner portions 17 can be present at a high temperature field in the vicinity of the burner portion 17 for a long time, gasification reaction of carbon in the coal is promoted, and the reaction rate can be increased. [0036] 5 As described above, the embodiment of the present invention is described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiment and includes modifications and the like within the scope which does not depart from the gist of the present invention. For example, in the embodiment, the shape of the burner portion 17 is 10 cylindrical. However, the shape may be a flattened cylindrical shape or an angled tubular shape if having a shape that extends along a predetermined axis line. In addition, in the embodiment, since the flow of fluid in the partial oxidation portion 12 becomes the rotating flow even when the burner portion 17 is not disposed at equal intervals around the center axis line C2 of the partial oxidation portion 12, the 15 burner portion 17 may be not disposed at equal intervals around the center axis line C2. [0037] Moreover, in the coal gasifier, similar to the burner portions 17, a char burner may be disposed on a second reference plane parallel to the reference plane P1 immediately above the burner portions 17 in the partial oxidation portion 12. That is, 20 when the char burner is viewed from the upper portion DI, the char burner may be disposed so that the axis line of the char burner contacts around the same direction on a virtual circle which has a smaller diameter than the inner diameter RI of the partial oxidation portion 12 and has the center axis line C2 as the center. In addition, the char burner may be disposed so that the axis line of the char burner is parallel to the horizontal 25 surface or is inclined toward the lower portion as the axis line approaches the tip of the 22 char burner. Moreover, with respect to the recycle, the char burner is not used, the char and the coal are uniformly mixed, and the mixture may be supplied to the burner portions 17. In addition, in the embodiment, a thermal decomposition portion is provided on 5 the upper portion of the partial oxidation portion 12, the coal is blown into the synthesis gas composed primarily of high temperature hydrogen gas and carbon monoxide gas from the partial oxidation portion 12, and the heat of the synthesis gas may be used for thermal decomposition. 10 EXAMPLES [0038] In the partial oxidation portion 12 of the coal gasifier 4, the diameter of the inner circumferential surface was set to 0.65 (m), the height of the inner portion was 1.0 (m), and four burner portions 17 were provided in the partial oxidation portion 12 at equal 15 intervals. Moreover, tests were carried out using bituminous coal containing ash of 5% as the coal. The mean flow speed Va of the burner portion 17 was set to 30 (m/s) and the furnace was operated while the diameter ratio was changed from 1/3 to 1/5. As a result, compared to the case where the diameter ratio was set to 1/3, in the case where the 20 diameter ratio was set to 1/5, it was found that approximately 20% of the heat loss which was transmitted from the partial oxidation portion 12 to the water and the like in the cooling wall conduit 22 was decreased. In addition, the diameter ratio of the partial oxidation portion 12 was fixed to 1/3 and the furnace was operated while the mean flow speed Va of the burner portion 17 was 25 changed from 50 (m/s) to 30 (m/s). As a result, compared to the case where the mean 23 flow speed Va was set to 50 (m/s), in the case where the mean flow speed Va was set to 30 (m/s), it was found that approximately 10% of the heat loss was decreased. Moreover, when the furnace was operated while the diameter ratio was changed from 1/3 to 1/5 and the mean flow speed Va was changed from 50 (m/s) to 30 (m/s), 5 approximately 20% of the heat loss was decreased. [0039] In addition, in the coal gasifier 4 having the shape of the Example, the coal having the ash of 1% was gasified and the furnace was operated while the diameter ratio was set to 1/4 and the mean flow speed Va was set to 10 (m/s). As a result, it was found 10 that the slag attached to the inner circumferential surface of the partial oxidation portion 12 could be maintained so as to be a constant thickness. However, if the ash is 3% or more, the heat loss is the same as the case where the ash is 5%, and it is found that the heat loss when the ash is 5% is decreased approximately 30% more than the heat loss when the ash is 1%. 15 REFERENCE SIGNS LIST [0040] 4: coal gasifier 12: partial oxidation portion (reaction vessel) 20 17a to 17h: burner portion Cl: axis line C2: center axis line E: virtual circle P1: reference plane 25 0: angle 24

Claims

1. A coal gasifier in which at least hydrogen gas and carbon monoxide gas are produced by gasifying coal in a reaction vessel, comprising: a reaction vessel that is formed in a cylindrical shape that extends upward; an outlet that is provided on the upper end side of the reaction vessel; and a plurality of cylindrical burner portions that supply the coal and oxidizing agent to the reaction vessel, wherein the plurality of burner portions are provided with an interval toward the circumferential direction of an inner circumferential surface of the reaction vessel on a reference plane that is parallel to a horizontal surface positioned downward from the outlet, when the reaction vessel is viewed from above, each of the burner portions is disposed so that an axis line of each burner portion contacts around the same direction on a virtual circle that has a diameter smaller than an inner diameter of the reaction vessel that has a center axis line of the reaction vessel as the center, the burner portion is disposed so that the axis line of the burner portion is parallel to the horizontal surface or is inclined downward as the axis line approaches the tip of the burner portion, and when mass flow rates of the coal and the oxidizing agent that are supplied to the reaction vessel from each of the burner portions are represented by ml (kg/s) and m2 (kg/s) respectively, and flow speeds of the coal and the oxidizing agent in each of the burner portions are represented by V I (m/s) and V2 (m/s) respectively, a mean flow speed Va (m/s) according to Equation (1) is set to 10 (m/s) or more and 50 (m/s) or less. Va = (ml x VI + m2 x V2) / (ml + m2) ... (1) 26

2. The coal gasifier according to claim 1, wherein the burner portion is disposed at equal intervals around the center axis line of the reaction vessel.

3. The coal gasifier according to claim 1, wherein a ratio of the diameter of the virtual circle with respect to the inner diameter of the reaction vessel is set to 1/10 or more and 1/3 or less.

4. The coal gasifier according to claim 1, wherein an angle of the axis line of each of the burner portions with respect to the horizontal surface is set to 0* or more and 100 or less.

5. The coal gasifier according to claim 2, wherein a ratio of the diameter of the virtual circle with respect to the inner diameter of the reaction vessel is set to 1/10 or more and 1/3 or less.

6. The coal gasifier according to claim 2, wherein an angle of the axis line of each of the burner portions with respect to the horizontal surface is set to 00 or more and 10' or less.

7. The coal gasifier according to claim 3, wherein an angle of the axis line of each of the burner portions with respect to the horizontal surface is set to 0* or more and 100 or less. 27

8. The coal gasifier according to claim 5, wherein an angle of the axis line of each of the burner portions with respect to the horizontal surface is set to 0* or more and 100 or less.

9. A coal gasifier substantially as hereinbefore described with reference to the accompanying drawings. Nippon Steel & Sumikin Engineering Co., Ltd. Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON