WO2011129192A1 - Coal gasification system and coal gasification method - Google Patents

Abstract

Disclosed are a coal gasification system and a coal gasification method, comprising a drying apparatus which turns subbituminous coal or brown coal into moisture-regulated coal by drying until same contain a specified moisture content; and a coal gasification reaction furnace which produces at least hydrogen gas and carbon monoxide gas by burning the moisture-regulated coal. The specified moisture content is set to a quantity such that when the moisture vapour emitted from the moisture-regulated coal and tar are chemically reacted, the tar does not stick inside through holes.

Description

Coal gasification system and coal gasification method

The present invention relates to a coal gasification system and a coal gasification method for producing a product such as methane using coal as a raw material.
Priority is claimed on Japanese Patent Application No. 2010-095497, filed April 16, 2010, the content of which is incorporated herein by reference.

Conventionally, coal having coal gasification reactors of various configurations such as fixed bed type, fluidized bed type, and fluidized bed type (jet bed) type to gasify coal and efficiently produce combustible gas etc. Gasification systems are being considered.
As one of them, for example, a coal gasification system disclosed in Patent Document 1 is known. This coal gasification system comprises a pyrolysis gasification reactor (upper reaction vessel) for pyrolyzing coal, a heat exchanger for recovering sensible heat from gas etc. generated from the pyrolysis gasification reactor, the gas, etc. And a desulfurizer that removes sulfur from the gas from which the char has been separated to purify the gas.

The pyrolysis gasification reactor is in communication with the high temperature gasification furnace (lower reaction vessel) on the lower side. The high temperature gasifier is supplied with coal, an oxygen-containing gas such as oxygen or oxygen-enriched air, and water vapor. The high temperature gasification furnace generates a high temperature gas mainly composed of hydrogen gas and carbon monoxide gas.
The pyrolysis gasification reactor is provided with a coal blowing nozzle for blowing coal into the pyrolysis gasification reactor, and a steam nozzle for adding water vapor in the pyrolysis gasification reactor. From the coal supplied from the coal blowing nozzle into the pyrolysis gasification reactor, char and volatile gas are generated by the pyrolysis reaction. The char generated here is decomposed into various gases by the following chemical reaction formula.

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

Patent Document 1 describes that, among the above chemical reaction formulas, the reaction rate of the chemical reaction formula (1) is about several times faster than the reaction rate of the chemical reaction formula (2). Supplying steam to make the inside of the pyrolysis gasification reactor a steam-enriched atmosphere is said to be extremely effective in decomposing char.
On the other hand, generally, the pyrolysis of coal generates a tar mainly composed of carbon and adheres to the inside of the pyrolysis gasification reactor. If the deposition amount of tar increases, finally, a part of the pyrolysis gasification reactor may be clogged with tar, and the pyrolysis gasification reactor may not be able to operate normally. However, this tar is also gasified by the chemical reaction of the above-mentioned chemical reaction formulas (1) and (2). Here, the deposition of tar includes the deposition of carbonaceous material derived from tar.

Japanese Patent Application Laid-Open No. 2002-155289

However, when the amount of water vapor supplied to the pyrolysis gasification reactor increases, the temperature in the pyrolysis gasification reactor decreases and the reaction rate of the above-mentioned chemical reaction becomes slow. In addition, in order to supply steam to the pyrolysis gasification reactor, a certain device such as a steam nozzle or a steam supply pump is required, and there is a problem that the coal gasification system is upsized.

The present invention has been made in view of such problems, and it is possible to control the amount of water vapor inside the upper reaction container without requiring an apparatus for supplying water vapor to the upper reaction container. The purpose is to provide a system and a coal gasification method.

In order to achieve the above object, a coal gasification system according to one aspect of the present invention comprises drying a coal to dry a moisture-adjusting coal having a predetermined moisture content; and burning the moisture-adjusting coal And a coal gasification reactor for producing hydrogen gas and carbon monoxide gas. The coal gasification reactor is provided with a lower reaction vessel; an upper reaction vessel provided above the lower reaction vessel and in communication with the lower reaction vessel; the moisture control coal and the oxygen-containing gas in the lower reaction vessel. A burner unit for supplying and burning the moisture control coal; and a nozzle unit for supplying the moisture control coal to the upper reaction vessel.

According to the above coal gasification system, the coal is dried by the drying device to an extent having a predetermined water content to obtain the water content adjusting coal. When the moisture control coal is supplied to the lower reaction vessel together with the oxygen-containing gas and burned in the burner unit, a high temperature gas mainly composed of carbon monoxide gas is generated inside the lower reaction vessel. The high temperature gas generated inside the lower reaction vessel flows into the upper reaction vessel. Furthermore, the water content adjusting coal is supplied to the upper reaction container through the nozzle unit separately from the amount supplied to the lower reaction container, and is heated by the high temperature gas flowing into the upper reaction container. When the moisture control coal is heated from the high temperature gas, the pyrolysis generates carbon-based tar and char. The tar and char chemically react with a predetermined amount of water left in the moisture control coal to gasify (see Formula (1)).
In general, coal such as subbituminous coal and lignite contains water of about 30 to 60% (weight%). Therefore, in the process of drying these, it is adjusted so that a predetermined amount of water remains, and the remaining water is used to generate water vapor to promote the gasification of tar. As a result, it is possible to prevent tar from adhering to the inside of the gasification reaction furnace without supplying steam to the upper and lower reaction vessels as in the prior art. As a result, it is possible to improve the temperature decrease in the furnace accompanying the increase in the amount of water vapor supplied to the gasification reactor, and the delay in the reaction rate of the chemical reaction resulting from the temperature decrease. In addition, since it is not necessary to provide equipment for supplying water vapor to the gasification reactor, downsizing of the coal gasification system can be realized.

The above-mentioned coal gasification system is a pressure measurement part which measures the difference between the pressure in the furnace below the nozzle part and the pressure in the furnace above the upper reaction vessel; and the pressure difference measured by the pressure measurement part And a controller configured to control the drying device based on the above to adjust the amount of water contained in the coal.

Tar tends to concentrate and adhere to the upper reaction vessel inner surface above the nozzle portion. Therefore, according to the coal gasification system of the present invention, the pressure measuring unit measures the difference between the pressure in the furnace below the nozzle and the pressure in the furnace above the upper reaction vessel. Then, when a pressure difference at which tar adhesion is recognized is detected, the drying device is controlled to increase the amount of water contained in the coal. When the water amount adjustment coal with increased water amount is heated from the high temperature gas, tar and char mainly composed of carbon are generated by thermal decomposition, and the water is vaporized to be water vapor. Tar and char chemically react with part of the generated water vapor and are gasified. Furthermore, the tar deposited on the inner surface of the reaction vessel chemically reacts with the remaining water vapor and is gasified. Thereby, it can suppress that tar adheres to the upper reaction container inner surface.

Further, a coal gasification system according to one aspect of the present invention is a drying apparatus for drying subbituminous coal or lignite containing 20% or more of moisture by mass ratio so as to contain a predetermined amount of moisture to obtain moisture-adjusted coal. And a coal gasification reactor for producing at least hydrogen gas and carbon monoxide gas by burning the moisture-regulated coal. The coal gasification reactor has a lower reaction vessel in which a storage space is formed, and an upper reaction vessel provided above the lower reaction vessel. The lower reaction vessel has a burner unit that supplies the moisture-adjusting coal and the oxygen-containing gas at a predetermined ratio without supplying water vapor to the lower reaction vessel and burns the moisture-adjusting coal. The upper reaction vessel supplies only the water content adjusting coal without supplying water vapor to the upper reaction vessel, and a through hole extending in the vertical direction in communication with the storage space of the lower reaction vessel via the reduced diameter portion It has a nozzle part that The predetermined amount is set such that the water does not adhere to the through holes by chemical reaction with the tar generated from the water amount adjusting coal.

Subbituminous coal and lignite contain water of about 30 to 60% (weight%). According to the present invention, first, the subbituminous coal or the lignite is dried by the drying apparatus to be the moisture control coal, and the moisture control coal is controlled so as to contain water higher than the residual moisture in the conventional coal gasification system. Specifically, in the upper reaction vessel, the chemical reaction between a predetermined amount of water of the moisture control coal and the tar generated from the moisture control coal causes a moisture control such that the tar does not adhere to the through holes. Adjust the amount of water in the coal.
Then, the moisture control coal and the oxygen-containing gas are supplied at a predetermined ratio without supplying water vapor from the burner unit to the storage space in the lower reaction container to burn the moisture control coal, and Only moisture regulation coal is supplied to the through hole without supplying water vapor from the nozzle portion.

Both carbon and water supplied into the upper reaction vessel are contained in the moisture control coal. By the thermal decomposition of the moisture control coal, tar and char mainly composed of carbon are formed. Moisture Content The moisture in the coal is heated in the upper reaction vessel to become water vapor. The tar, char and water vapor immediately after being produced from the moisture control coal are mixed. When these tar, char and water vapor are supplied from separate nozzles, the tar and char and the water vapor may be incapable of reacting due to their separated positions. However, according to the above aspect, since the tar, char and water vapor are mixed, it is possible to prevent them from becoming unreactive.
At this time, the amount of water contained in the amount-of-water control coal supplied into the upper reaction vessel is controlled by the drying device, and the tar and steam generated by the thermal decomposition of the amount-of-water control coal react with each other to cause through holes. There is an amount that tar does not stick inside. Therefore, the amount of tar adhering to the inside of the through hole does not increase and the through hole is not clogged. In this way, the steam and the tar and char mixed in the upper reaction vessel can be reacted more reliably. Therefore, it is possible to reduce or eliminate the water vapor supplied into the upper reaction vessel in order to prevent tar from adhering to the upper reaction vessel.

Moreover, in said coal gasification system, the said predetermined | prescribed water content may be set to mass ratio 15%-40% by content in the said water content adjustment coal.
In this case, by setting the water content in the water control coal to 15% or more by mass ratio, the reaction between tar and water vapor in the upper reaction vessel is further promoted, and tar does not adhere to the through holes. can do.

Further, in the above coal gasification system, the coal gasification reaction furnace is an internal pressure of a portion below the nozzle portion in the through hole of the upper reaction container or an internal pressure of a storage space of the lower reaction container, and the through hole The pressure measurement unit may be configured to measure a pressure difference between the pressure at the upper end portion of In this case, the coal gasification system may include a control unit that controls the drying device to adjust the water content of the coal based on the pressure difference measured by the pressure measurement unit.
In this case, even if tar generated by thermal decomposition of coal adheres to the upper reaction vessel, the tar is concentrated at a position vertically above the nozzle portion in the through hole of the upper reaction vessel. Adhere to. Therefore, by setting one of the positions at which the pressure difference is measured as the lower portion in the vertical direction from the nozzle portion in the through hole of the upper reaction container or the storage space of the lower reaction container, the other is the upper end of the through hole, The pressure difference can be reliably measured by preventing the tar from clogging the portion where the pressure difference is measured.
In addition, when tar adheres to the inside of the through hole, the pressure difference measured by the pressure measurement unit becomes large. At this time, the control unit can promote the chemical reaction between the tar and the steam by increasing the amount of water in the moisture control coal, and can gasify the tar deposited in the through holes of the upper reaction vessel .

The coal gasification method according to an aspect of the present invention implements the following steps using the coal gasification system described in any of the above. A drying step of drying the sub bituminous coal or lignite so as to have a predetermined water content to obtain the water content adjusting coal. The water content adjusting coal and the oxygen-containing gas are supplied to the lower reaction container without supplying steam from the burner part, and the water content adjusting coal is burned, and the upper reaction container is fed with the water from the nozzle part. A chemical reaction process in which only the water amount adjusting coal is supplied to cause a chemical reaction of the water amount adjusting coal.

In the above-described coal gasification method, in the chemical reaction step, at least the tar generated from the water amount adjusting coal and the water vapor generated by heating the water contained in the water amount adjusting coal are chemically reacted, Carbon monoxide gas and hydrogen gas may be produced.

In the coal gasification method according to one aspect of the present invention, the coal is dried to obtain a moisture control coal containing a predetermined moisture content; and the water control coal in the lower reaction vessel of the coal gasification reactor. And a step of supplying an oxygen-containing gas; a step of burning the moisture-regulating coal to generate a high-temperature gas; and an upper reaction vessel communicating with the lower reaction vessel of the coal gasification reactor with the moisture-regulating coal. And supplying the moisture-regulated coal supplied to the upper reaction vessel with the high-temperature gas flowing from the lower reaction vessel to the upper reactor.

When the water amount adjusting coal supplied to the upper reaction vessel is heated by the high temperature gas, the carbon-based tar and char are generated by thermal decomposition. The tar and char chemically react with a predetermined amount of water left in the moisture control coal to be gasified. As a result, it is possible to prevent tar from adhering to the inside of the gasification reaction furnace without supplying steam to the upper and lower reaction vessels as in the prior art. As a result, it is possible to improve the temperature decrease in the furnace accompanying the increase in the amount of water vapor supplied to the gasification reactor, and the delay in the reaction rate of the chemical reaction resulting from the temperature decrease. In addition, since it is not necessary to provide equipment for supplying water vapor to the gasification reactor, downsizing of the coal gasification system can be realized.

According to the coal gasification system and the coal gasification method of the present invention, the amount of water vapor in the upper reaction container can be adjusted without requiring an apparatus for supplying water vapor to the upper reaction container.

It is a block diagram of a coal gasification system concerning a 1st embodiment of the present invention. It is the figure which fractured a part of principal part of the same coal gasification system. It is sectional drawing of the drying apparatus of the same coal gasification system. It is a figure which shows the change of the content of the water | moisture content in moisture content adjustment coal with respect to the exit temperature of the crushing part of the same coal gasification system. It is a figure which shows the relationship of the increase rate of the adhesion amount of tar in a through-hole with respect to the moisture content in the moisture content adjustment coal in the same coal gasification system. It is the figure which fractured a part of principal part of a coal gasification system concerning a 2nd embodiment of the present invention. It is a figure which shows the relationship between the pressure difference measured with the pressure measurement apparatus of the same coal gasification system, and the water content in water content adjustment coal required in order to return the pressure difference to a normal value.

First Embodiment
Hereinafter, a first embodiment of a coal gasification system according to the present invention will be described with reference to FIGS. 1 to 5. As shown in FIG. 1, the coal gasification system 1 synthesizes a synthesis gas containing hydrogen gas and carbon monoxide gas as main components using coal as a raw material, and from this synthesis gas, finally, methane, methanol, ammonia and the like are produced. It is a plant facility that manufactures products. As coal used by coal gasification system 1 of this embodiment, subbituminous coal or lignite containing 20% or more of moisture by weight can be used.
The coal gasification system 1 includes a coal drying and pulverizing facility (drying apparatus) 2, a coal supply facility 3, a coal gasification reactor 4, a heat recovery facility 5, a char recovery facility 6, and a shift reaction facility 7. , Gas purification equipment 8, chemical synthesis equipment 9, and air separation equipment 10.

As shown in FIG. 2, the coal drying and crushing facility 2 has a drying unit 13 for heating coal and a crushing unit 14 for crushing coal to a predetermined particle diameter (outer diameter).
In general, coal has an uneven particle size, and subbituminous coal and brown coal contain a large amount of water of, for example, about 30 to 60% by mass ratio. Therefore, the sub-bituminous coal or lignite has a predetermined moisture content by grinding the sub-bituminous coal or lignite heated in the drying unit 13 into particles having a particle diameter of, for example, about 10 μm to 100 μm in the crushing unit 14. Adjust as. In this manner, a moisture-regulated coal having a predetermined moisture content is produced from coal having a moisture content of about 30 to 60% by mass ratio. Since moisture is evaporated from the coal by making the heated coal into particles, the moisture content in the moisture content adjustment coal is determined when the moisture content adjustment coal comes out of the grinding unit 14. Thus, the drying unit 13 and the crushing unit 14 both function as a drying apparatus for drying coal.
The moisture content of granular moisture control coal produced by the coal drying and pulverizing facility 2 is set to be 15% or more and 40% or less by mass ratio, which is lower than the moisture content of coal before drying.
The measurement of the moisture content of coal before drying and the measurement of the moisture content of dried and pulverized water can be performed using, for example, an infrared moisture meter. For example, by adjusting the heating temperature or heating time in the drying unit 13 or the particle size of coal after crushing in the crushing unit 14, it is possible to adjust the water content of the water amount adjusting coal.

As shown in FIG. 3, the drying unit 13 is configured by a double-pipe structure of an inner cylinder 15 and an outer cylinder 16 coaxially disposed. The inner cylinder 15 and the outer cylinder 16 are disposed such that the tip end side is inclined downward at a constant angle with respect to the horizontal plane. A hopper 17 for introducing coal B into the inner cylinder 15 is connected to the base end side (the obliquely upper side in the vertical direction) of the inner cylinder 15. In the inner cylinder 15, a delivery mechanism 18 for delivering the coal B to the tip side (obliquely lower side in the vertical direction) is disposed.
At the tip of the outer cylinder 16, a flow rate adjusting valve 19 is connected between the outer cylinder 16 and the inner cylinder 15 to supply water vapor at a constant temperature by adjusting the flow rate. The steam supplied between the inner cylinder 15 and the outer cylinder 16 flows so as to face the direction in which the coal B is sent, and is discharged from the discharge pipe 20 connected to the outer cylinder 16.
At the outlet of the pulverizing unit 14 shown in FIG. 2, a temperature sensor for measuring the outlet temperature of the pulverizing unit 14 is provided.

The drying unit 13 configured as described above operates the flow rate adjusting valve 19 while measuring with the temperature sensor of the crushing unit 14 to adjust the amount of water vapor flowing between the inner cylinder 15 and the outer cylinder 16. And, while conveying the coal B to the tip side inside the inner cylinder 15, the coal B is heated by the steam. Thereby, the amount of water contained in coal B is adjusted.
In addition, the method of drying coal in a drying part will not be specifically limited if the amount of moisture in coal can be adjusted. For example, as in the present embodiment, a method of heating coal with steam may be used, or a method of heating using a heater or the like may be used. By using the drying unit 13 of the present embodiment shown in FIG. 3, it is possible to simultaneously carry out the grinding and drying of coal with one device, and it is possible to make the equipment compact and reduce the cost.

FIG. 4 shows an example of the result of drying the coal B by the coal drying and crushing facility 2. In addition, in FIG. 4, coal B is primarily dried and the water content in coal B is supplied to the drying unit 13 in a state of being dried to 25%. The horizontal axis in FIG. 4 indicates the outlet temperature of the grinding unit 14 measured by the temperature sensor, and the vertical axis indicates the water content in the moisture-adjusting coal after leaving the grinding unit 14. According to this test result, when the outlet temperature of the crushing unit 14 is 75 ° C., the moisture content of the moisture adjustment coal is 5%, and when the outlet temperature of the crushing unit 14 is 50 ° C., the moisture content in the moisture adjustment coal is 18 %Met.
As the flow rate of the water vapor flowing between the inner cylinder 15 and the outer cylinder 16 increases, the outlet temperature of the crushing unit 14 becomes higher. Then, when the outlet temperature of the crushing part 14 becomes high, it is understood that the coal B is heated to a higher temperature in the inner cylinder 15, and the water content in the water amount adjusting coal discharged from the outlet of the crushing part 14 decreases. .

As shown in FIG. 2, the water amount adjusting coal pulverized in the pulverizing unit 14 is mixed with the carrier gas in the coal supply facility 3 in order to be able to be supplied into the coal gasification reactor 4. The carrier gas containing the moisture content adjusting coal is pressurized to a predetermined pressure and supplied to the coal gasification reaction furnace 4. In addition, the moisture content adjustment coal which evaporated the fixed amount of water | moisture content of the inside after leaving the drying part 13 is filled with the dry nitrogen so that a moisture content may not change, and moves in the sealed space.
The air separation equipment 10 shown in FIG. 1 compresses and liquefies air, and separates oxygen gas, nitrogen gas, and the like which are dried from the air that has become a liquid due to the difference in boiling point. The oxygen gas separated by the air separation facility 10 is supplied to the coal gasification reactor 4.

As shown in FIG. 2, the coal gasification reaction furnace 4 is an apparatus for producing at least hydrogen gas and carbon monoxide gas by burning moisture control coal inside. The coal gasification reaction furnace 4 includes a partial oxidation unit (lower reaction vessel) 26 and a thermal decomposition unit (upper reaction vessel) 28 provided on the upper side D 1 in the vertical direction of the partial oxidation unit 26. The partial oxidation portion 26 has a storage space 26 a formed therein. The thermal decomposition section 28 has a through hole (tubular section) 27 extending in the up-and-down direction D in communication with the accommodation space 26 a of the partial oxidation section 26 via the reduced diameter section 28 a. The coal gasification reaction furnace 4 is formed of a heat-resistant brick or the like.
By providing the diameter-reduced portion 28a between the through hole 27 and the housing space 26a, it is possible to operate the partial oxidation portion 26 and the thermal decomposition portion 28 under independent reaction conditions.
A slag cooling water tank 29 is provided below the partial oxidation unit 26 at D2. The partial oxidation portion 26 and the slag cooling water tank 29 communicate with each other in the vertical direction (vertical direction) D. A small diameter portion whose diameter is reduced is formed at a connection portion between the partial oxidation portion 26 and the slag cooling water tank 29.

The partial oxidation portion 26 is formed in a substantially cylindrical shape extending in the vertical direction D. A plurality of gasification burners (burner units) 30 formed in a cylindrical shape extending along the axis C1 are provided on the inner peripheral surface of the partial oxidation unit 26. The gasification burner 30 is connected to the coal supply facility 3 and the air separation facility 10, and the partial oxidation unit 26 is a moisture control coal and an oxygen-containing gas, and (hereinafter referred to as "moisture control coal etc." Can be supplied at a predetermined rate. The gasification burner 30 is disposed such that its tip end side is directed obliquely downward with respect to the horizontal plane, and its axis C 1 is at a position of twist with respect to the central axis C 2 of the partial oxidation portion 26. Thereby, the gasification burner 30 is arranged such that the flow of the gas to be jetted becomes a swirling flow that swirls about the central axis C2 of the partial oxidation unit 26.
Further, a cooling means (not shown) is provided on the outer peripheral surface of the partial oxidation portion 26, and the partial oxidation portion 26 heated by the combustion of the moisture content adjusting coal can be cooled.

The thermal decomposition section 28 is formed in a tubular or cylindrical shape extending in the up-down direction D. The inner diameter of the through hole 27 is smaller than the inner diameter of the accommodation space 26 a of the partial oxidation portion 26.
A plurality of nozzle portions 31 for supplying only the moisture content adjusting coal to the thermal decomposition portion 28 is provided in the middle portion of the thermal decomposition portion 28 in the vertical direction D. The nozzle portion 31 is connected to the coal supply facility 3.
The thermal decomposition unit 28 is not provided with a steam nozzle for supplying water vapor to the thermal decomposition unit as in the conventional thermal decomposition unit. Further, the number of the gasification burner 30 and the number of the nozzle portion 31 is not limited, and may be any number.
The end portion 27 a of the upper portion D 1 of the through hole 27 of the thermal decomposition section 28 is connected to the heat recovery facility 5.

Further, in the present embodiment, the coal gasification system 1 is provided with a pressure measurement device (pressure measurement unit) 33 that measures the pressure difference in the through holes 27 of the thermal decomposition unit 28. The pressure measuring device 33 has a first pipe 34, a second pipe 35, and a main body 36. The first pipe 34 is connected to the accommodation space 26 a of the partial oxidation portion 26, and the second pipe 35 is connected to the end 27 a of the through hole 27. The main body 36 measures a pressure difference between the internal pressure of the first pipe 34 and the internal pressure of the pipe of the second pipe 35.
A predetermined amount of water W is accommodated in the slag cooling water tank 29, and as described later, the slag flowing from the partial oxidation unit 26 is cooled.

When the coal gasification reaction furnace 4 configured as described above is operated, the chemical reaction process described below is performed.
First, the moisture control coal and the like are supplied from the gasification burner 30 into the partial oxidation unit 26 at a predetermined flow rate. Each gasification burner 30 is arrange | positioned so that the flow of the gas to blow off may turn into a swirling flow as mentioned above. Therefore, the water content adjusting coal or the like jetted from the gasification burner 30 becomes a swirling flow rotating around the central axis C2 of the partial oxidation unit 26 while advancing downward D2. At this time, the inside of the partial oxidation portion 26 is high temperature and high pressure (for example, the temperature is 1300 ° C. or more and 1700 ° C. or less, and the pressure is 2 MPa or more and 3 MPa or less). Under this environment, moisture control coal becomes high temperature and is pyrolyzed. In this process, char and volatile gases including tar and water vapor are generated separately. In addition, the combustion of the water content adjusting coal generates high temperature carbon monoxide gas, carbon dioxide gas, hydrogen gas and slag (ash) according to the following chemical reaction formulas (3) to (5).

2C + O ₂ → 2CO (3)
C + O ₂ → CO ₂ (4)
C + H ₂ O → CO + H ₂ (5)

The gas, slag and the like generated in the partial oxidation portion 26 expand at high temperature and expand by receiving a force in the upward direction D1 by buoyancy, and ascends in the partial oxidation portion 26 while turning.
The slag generated in the partial oxidation portion 26 is in a molten state. A part of the slag is cooled by the above-mentioned cooling means on the inner peripheral surface of the partial oxidation portion 26 and adheres to the inner peripheral surface, and the other portion is provided inside the slag cooling water tank 29 provided below the partial oxidation portion 26. It is dropped into water W, cooled, and recovered.

Gas such as water vapor generated in the partial oxidation unit 26, tar, char and the like are sent out from the partial oxidation unit 26 and rise in the through holes 27 of the thermal decomposition unit 28. The temperature in the partial oxidation portion 26 is adjusted to 1000 ° C. or more, and the pressure is adjusted to 1 MPa or more.
The nozzle portion 31 supplies the moisture control coal to the inside of the through hole 27. The moisture control coal is dried by the coal drying and grinding facility 2 and adjusted to have the above-mentioned predetermined moisture amount.
The water amount adjustment coal supplied from the nozzle unit 31 generates tar by thermal decomposition. In addition, a predetermined amount of water contained in the water amount adjusting coal is heated to become water vapor. The tar and water vapor generated from the water amount adjusting coal supplied from the nozzle 31 are mixed with the tar and water vapor rising from the inside of the partial oxidation portion 26, and carbon monoxide gas and carbon monoxide gas are obtained according to the following chemical reaction formula (6). It is decomposed into hydrogen gas.
In addition, a part of carbon in the water amount adjustment coal supplied to the thermal decomposition unit 28 reacts with carbon dioxide gas in the thermal decomposition unit 28 and becomes carbon monoxide gas by the following chemical reaction formula (7) .

C (tar) + H ₂ O → CO + H ₂ (6)
C + CO ₂ → 2 CO (7)

Here, FIG. 5 shows the relationship between the rate of increase of the amount of deposition of tar in the through holes 27 and the amount of water in the moisture control coal. The horizontal axis in FIG. 5 represents the amount of water in the moisture-regulating coal, and the vertical axis represents the rate of increase in the amount of attached tar.
Water content control As the water content in the coal increases, the reaction between tar and water vapor is promoted, and the rate of increase in the amount of tar attached decreases. Specifically, if the amount of water in the water amount adjusting coal is smaller than 15%, the amount of adhesion of tar increases and tar adheres in the through holes 27. On the other hand, if the water content in the moisture control coal is greater than 15%, tar will not adhere in the through hole 27 and even if tar adheres in the through hole 27 for some reason, the tar will It is decomposed into gas and disappears.
Incidentally, even if the coal having a water content of about 60% is crushed in the crushing part 14 without heating in the drying part 13, the water is evaporated from the crushed coal, so the water content in the water amount adjustment coal is 40 It does not exceed%. Thus, when the water content in the water amount adjusting coal is 40% or less by mass ratio, it is possible to prevent the above-mentioned chemical reaction from being delayed by the water vapor generated from the water amount adjusting coal.
By the above procedure, the chemical reaction process is completed.

Then, as shown in FIG. 1, a high temperature synthesis gas containing hydrogen gas and carbon monoxide gas as main components is transported from the thermal decomposition unit 28 together with char and is supplied to the heat recovery facility 5.
In the heat recovery facility 5, the temperature of the steam rises due to the heat exchange between the synthesis gas transported from the thermal decomposition unit 28 and the steam outside. This water vapor is supplied to the aforementioned drying unit 13 and the like for the purpose of drying coal etc.
The synthesis gas cooled by the heat recovery facility 5 is supplied from the heat recovery facility 5 to the char recovery facility 6, and the char recovery facility 6 recovers the char contained in the synthesis gas.
The synthesis gas that has passed through the char recovery facility 6 is supplied to the shift reaction facility 7. Then, in order to increase the ratio of hydrogen gas to carbon monoxide gas in the synthesis gas to a certain value, steam is supplied into the shift reaction facility 7. In the shift reaction equipment 7, carbon dioxide gas and hydrogen gas are generated from carbon monoxide gas and water vapor in synthesis gas by the shift reaction represented by the following chemical reaction formula (8).

CO + H ₂ O → CO ₂ + H ₂ (8)

The synthesis gas whose components have been adjusted in the shift reaction equipment 7 is supplied to the gas purification equipment 8, and carbon dioxide gas contained in the synthesis gas, a gas containing sulfur as a component, and the like are recovered.
The synthesis gas purified by the gas purification facility 8 is supplied to the chemical synthesis facility 9 to produce products such as methane and methanol.

Next, in the coal gasification system 1 configured as described above, the operation method in the case where tar adheres to the through holes 27 due to some factor is described with emphasis on the drying unit 13 and the coal gasification reactor 4 Do.
As shown in FIG. 4, when the temperature of the temperature sensor of the crushing part 14 is T0, it is assumed that the water content of the water content adjustment coal obtained is X0. The case where the coal gasification reaction furnace 4 is operated without the tar adhering to the through holes 27 by supplying the moisture control coal from the nozzle part 31 of the coal gasification reaction furnace 4 will be described.
It is assumed that tar adheres in the through hole 27 and the pressure difference measured by the pressure measuring device 33 becomes larger than the set value. At this time, the driver reduces the flow rate of the water vapor flowing through the drying unit 13 by a predetermined amount using the flow rate adjustment valve 19 of the drying unit 13. As a result, the temperature of the temperature sensor is lowered to T1 and the water content of the moisture control coal obtained by the drying unit 13 is increased from X0 to X1.
By supplying the water amount adjusting coal having the water amount increased to X1 from the nozzle portion 31 into the through hole 27, more water vapor is generated from the water amount adjusting coal. Then, the reaction between the tar attached to the through hole 27 and the water vapor is promoted by the chemical reaction formula (6), and the attached tar gasifies and disappears.

When the pressure difference is reduced to about the pressure difference during normal operation, the flow control valve 19 is used to control the flow rate of the steam flowing through the drying unit 13 in order to maintain the reaction speed in the thermal decomposition unit 28 at a predetermined value or more. The flow rate may be increased. Thereby, the temperature of the temperature sensor may be raised to, for example, T0 or T2, and the water content of the water content adjusting coal may be reduced to X0 or X2.

As described above, according to the coal gasification system 1 of the present embodiment, first, the sub-bituminous coal or the lignite containing 20% or more of moisture by weight ratio is dried by the coal drying and grinding facility 2. Then, a moisture control coal having a predetermined moisture amount larger than the residual moisture amount in the conventional coal gasification system is manufactured. Specifically, in the thermal decomposition portion 28, the predetermined amount of water contained in the water amount adjusting coal chemically reacts with the tar generated from the water amount adjusting coal so that the tar does not adhere to the through holes 27 As such, adjust the amount of water in the coal.
Then, the moisture control coal and the oxygen-containing gas are supplied at a predetermined ratio without supplying steam from the gasification burner 30 to the storage space 26 a in the partial oxidation unit 26 to burn the moisture control coal. At the same time, only moisture content adjustment coal is supplied to the through holes 27 in the thermal decomposition section 28 without supplying water vapor from the gasification burner 30. Here, the oxygen-containing gas refers to a gas containing oxygen, and includes not only oxygen gas but also air and oxygen-enriched air. However, in order not to reduce the calorific value of the synthesis gas generated in the thermal decomposition section 28, it is preferable to use a high concentration oxygen gas having an oxygen content of 85% or more as the oxygen-containing gas.

Both carbon and water supplied into the thermal decomposition section 28 are contained in the moisture control coal, and from the moisture control coal, tar and char mainly composed of carbon are generated by thermal decomposition. Further, the moisture in the moisture control coal is heated in the thermal decomposition section 28 to become steam. The tar, char and water vapor immediately after being produced from the moisture control coal are mixed. Therefore, as in the case where they are supplied from separate nozzles, water vapor is supplied to a position away from tar and char, which prevents them from becoming unresponsive.
At this time, the amount of water in the water amount adjusting coal supplied to the inside of the thermal decomposition portion 28 is adjusted to such an amount that the tar and the steam chemically react with each other by the coal drying and grinding facility 2 and tar does not adhere in the through holes 27 It is done. Therefore, the amount of tar adhering to the through hole 27 does not increase and the through hole 27 is not clogged. Then, the steam supplied from the outside into the thermal decomposition unit 28 from the outside is prevented in the prior art in order to prevent the tar from adhering by reacting the steam, tar and char in the mixed state in the thermal decomposition unit 28 more reliably. The chemical reaction in the thermal decomposition section 28 can be promoted by reducing or eliminating the need.

Further, the moisture is supplied to the thermal decomposition section 28 in a state of being contained in the moisture control coal. Therefore, a device for supplying steam to the thermal decomposition unit 28 such as a steam nozzle is not necessary, and the manufacturing cost of the coal gasification system 1 can be reduced.
In order to dry the coal in the coal drying and grinding facility 2, a certain amount of energy is required to heat the coal. In the present embodiment, coal having a high water content is supplied to the thermal decomposition unit 28 without being dried to the residual water content of coal in a conventional coal gasification system. And, by causing the water in the moisture control coal to react effectively in the thermal decomposition section 28, it is possible to reduce part of the energy that was conventionally required to dry the coal.

Furthermore, by setting the amount of water in the water amount adjusting coal to 15% or more, the reaction between tar and water vapor in the thermal decomposition portion 28 can be further promoted, and tar can be prevented from adhering to the through holes 27. .

In addition, depending on the conditions, tar generated by thermal decomposition of the moisture control coal may be attached. In such a case, based on the test results, the inventors have determined that the predetermined position D1 above the nozzle portion 31 in the through hole 27 of the thermal decomposition portion 28 (for example, several hundred mm in the upper portion D1 above the nozzle portion 31) It was found that tar was attached intensively at the position). That is, the first pipe 34 of the pressure measuring device 33 is connected to the accommodation space 26 a of the partial oxidation unit 26, and the second pipe 35 is connected to the end 27 a of the upper D 1 of the through hole 27. By configuring the pressure measuring device 33 in this manner, it is possible to prevent the pipes 34 and 35 from being clogged by tar and to reliably measure the pressure difference.
Since it is known that tar does not easily adhere to the portion D2 lower than the nozzle portion 31 in the through hole 27 of the thermal decomposition portion 28, the first pipe 34 may be connected to this portion.

Further, in the present embodiment, when the adhesion amount of tar in the through hole 27 of the coal gasification reaction furnace 4 can be measured by another means such as an industrial endoscope, the pressure measurement device 33 is not provided. It is also good.
It is not necessary for the water contained in the moisture control coal supplied to the partial oxidation unit 26 and the water contained in the moisture control coal supplied to the thermal decomposition unit 28 to be the same. For example, by preparing two lines of coal drying and crushing and supply system equipment, it is possible to supply moisture-regulating coal having different moisture amounts to the partial oxidation unit 26 and the thermal decomposition unit 28. Water content adjustment coal supplied to the partial oxidation unit 26 will be reduced if the amount of water in the coal is too high, leading to a decrease in efficiency, and water contained in the water amount adjustment coal supplied to the thermal decomposition unit 28 will be large because it leads to adhesion prevention Is preferred.

Second Embodiment
Next, a second embodiment of the present invention will be described. The same parts as those in the first embodiment described above are denoted by the same reference numerals, and descriptions thereof will be omitted. Only differences from the first embodiment will be described.
As shown in FIG. 6, the coal gasification system 41 of the present embodiment has the water content based on the pressure difference measured by the pressure measurement device 33 in addition to the components of the coal gasification system 1 of the first embodiment. The control unit 42 is provided to adjust the amount of water in the adjustment coal.

The control unit 42 includes a memory and an arithmetic unit (not shown). The control unit 42 is electrically connected to the pressure measuring device 33, the drying unit 13, and the temperature sensors of the crushing unit 14. In the memory, as shown in FIG. 7, the relationship between the temperature of the temperature sensor of the crushing unit 14 as shown in FIG. 4 and the amount of water in the moisture control coal after leaving the coal drying and crushing facility 2; A relational expression between the pressure difference measured by the pressure measuring device 33 and the water amount in the water amount adjusting coal necessary to return the pressure difference to a normal value is stored.
Further, the arithmetic unit can receive the signal from the pressure measurement device 33 and can control the drying unit 13 based on the above-described relational expression stored in the memory.

Next, in the coal gasification system 41 configured as described above, the operation method in the case where tar adheres to the through holes 27 due to some factor is focused on the drying unit 13, the coal gasification reactor 4 and the control unit 42. I will explain.
In addition, when the temperature of the temperature sensor of the crushing part 14 is T0 similarly to the driving | running method in said 1st Embodiment, it is assumed that the water content of the water content adjustment coal obtained is X0. By supplying the moisture control coal from the nozzle portion 31, the pressure difference measured by the pressure measuring device 33 becomes P0 (see FIG. 7), and the coal gasification reaction furnace 4 is operated without tar adhering to the through holes. The case where it is done is explained.
It is assumed that tar adheres in the through hole 27 and the pressure difference measured by the pressure measuring device 33 increases from P0 to P1 shown in FIG. At this time, the arithmetic unit of the control unit 42 detects that the pressure difference has become large by receiving the signal from the pressure measuring device 33. Then, the arithmetic unit calculates X1 of the water content corresponding to P1 of the pressure difference from the relational expression between the pressure difference of the pressure measuring device 33 and the water content adjustment coal shown in FIG. 7 stored in the memory. . Furthermore, the arithmetic unit calculates T1 of the temperature of the temperature sensor corresponding to X1 of the water content from the relational expression between the temperature of the temperature sensor and the water content adjustment in the moisture adjustment coal shown in FIG.
Subsequently, the arithmetic unit controls the drying unit 13 to adjust the temperature of the temperature sensor to T1. By controlling in this manner, the water amount adjusting coal whose water amount has increased to X1 is supplied from the nozzle portion 31 of the coal gasification reaction furnace 4 into the thermal decomposition portion 28. As a result, the reaction between the tar attached to the through hole 27 and the steam is promoted, and the attached tar is gasified and disappears.
If the pressure difference measured by the pressure measuring device 33 becomes too large, the time for gasifying and extinguishing the attached tar becomes long. Therefore, it is preferable that the control unit 42 start the above control when the pressure difference measured by the pressure measuring device 33 rises by 10 to 30% compared to that in the normal operation.

Here, it is assumed that the pressure difference measured by the pressure measuring device 33 is reduced to about the pressure difference during normal operation and becomes P0 or P2 (see FIG. 7). At this time, in order to maintain the reaction speed at a predetermined value or more, the arithmetic unit calculates T0 and T2 of the temperature corresponding to P0 and P2 of the pressure difference from both relational expressions, and sets the temperature of the temperature sensor to T0 or T2. The water content of the water control coal may be reduced to X0 or X2 by adjustment.

As described above, according to the coal gasification system 41 of the present embodiment, the amount of water supplied to the thermal decomposition unit 28 can be adjusted without requiring an apparatus for supplying water vapor to the thermal decomposition unit 28.
Furthermore, when tar adheres to the inside of the through hole 27, the pressure difference measured by the pressure measuring device 33 becomes large. At this time, the chemical reaction between tar and water vapor is further promoted by the arithmetic unit increasing the moisture content of the coal by adjusting the amount of moisture by the coal drying and grinding facility 2, and the tar adhering to the through holes 27 of the thermal decomposition section 28 Can be gasified.

The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and changes in the configuration without departing from the scope of the present invention are also included.
For example, in the first embodiment and the second embodiment, depending on the operating conditions of the coal gasification reaction furnace 4, the water amount adjusting coal to be supplied to the partial oxidation unit 26 from the amount of steam required for the partial oxidation unit 26 It is conceivable that the amount of water contained in the medium is higher. In this case, in the coal drying and crushing facility 2, two types of coal, one containing a water content suitable for supplying to the thermal decomposition part 28, and the coal for the partial oxidation part 26 having a water content smaller than that of coal. Manufacture. Then, the two types of coal may be supplied to each of the partial oxidation unit 26 and the thermal decomposition unit 28.

With the above coal gasification system 1, the temperature in the partial oxidation unit 26 is 1300 ° C., the water content adjustment coal supplied from the gasification burner 30 into the partial oxidation unit 26 is 18% water content adjustment coal, oxygen-containing gas The flow rates of oxygen gas (in the present embodiment) were 650 (kg / h) and 345 (Nm ³ / h), respectively. Water vapor is not supplied to the partial oxidation unit 26.
In addition, the drying apparatus used the apparatus which doubles as a grinder shown in FIG. 3, and dried and grind | pulverized coal so that it might become a granule of 10 micrometers or more and 100 micrometers or less.
Under this condition, tar is not attached to the through-hole 27 when 150 kg / h of water-regulating coal with a water content of 18% is supplied from the nozzle portion 31 to the thermal decomposition portion 28 and steam is not supplied. I found that.
Thus, in the coal gasification system 1 according to the embodiment of the present invention, tar can be prevented from adhering and stable operation can be performed without installing devices such as a steam nozzle and a steam supply pump. The equipment as a whole could be made into a compact equipment configuration.
As a comparative example, 561 (kg / h) of coal (water content 5%), 345 (Nm ³ / h) of oxygen-containing gas (oxygen gas in this comparative example), 89 of water vapor in the partial oxidation portion 26 (Kg / h) supply. Further, 130 (kg / h) of coal having a water content of 5% and 22 (kg / h) of steam are supplied from the nozzle unit 31 to the thermal decomposition unit 28. In this case, it was found that no tar adheres to the through holes 27. However, devices such as a steam nozzle and a steam supply pump are required, and the size of the entire device is increased as compared with Example 1, and the facility cost is also increased.

The pressure difference between the inside of the partial oxidation unit 26 and the thermal decomposition unit 28 was measured by the first pipe 34 and the second pipe 35 using the above-described coal gasification system 1. Then, coal 606 (kg / h) having a water content of 10% and oxygen-containing gas (oxygen gas in the present embodiment) 330 (Nm ³ / h) were supplied into the partial oxidation section 26. In addition, 136 (kg / h) of water content adjusting coal having a water content of 12% was supplied from the nozzle portion 31 into the thermal decomposition portion 28 and operated. In addition, the drying apparatus used the apparatus which served as the crusher of FIG. 3, and dried and grind | pulverized coal so that it might become a granular form of 10 micrometers or more and 100 micrometers or less.
As a result, the pressure difference between the inside of the partial oxidation unit 26 and the thermal decomposition unit 28 began to rise about 20 hours after the start of operation. The outlet gas temperature of the grinding unit 14 was lowered from 65 ° C. to 45 ° C. when the pressure difference rose about 20% before rising. As a result, the water content contained in the water content adjustment coal became 18% in mass ratio. And when this water content adjustment coal began to be introduced into the reactor, it was confirmed that the pressure difference between the inside of the partial oxidation unit 26 and the thermal decomposition unit 28 decreased, and the pressure almost returned to the level before the pressure difference rise.

As mentioned above, although the preferable embodiment of this invention was described, this invention is not limited to said embodiment. Additions, omissions, substitutions, and other modifications of the configuration are possible without departing from the spirit of the present invention. The invention is not limited by the foregoing description, but is only limited by the scope of the appended claims.

According to the coal gasification system and the coal gasification method, the amount of water vapor in the upper reaction container can be adjusted without requiring an apparatus for supplying water vapor to the upper reaction container.

1, 41 coal gasification system 2 coal drying and pulverizing equipment (drying device) 4 coal gasification reactor 26 partial oxidation part (lower reaction vessel) 26a accommodation space 27 through hole 28 thermal decomposition part (upper reaction vessel) 28a diameter reduction Unit 30 Gasification burner (burner unit) 33 Pressure measuring device (pressure measurement unit) 42 Control unit D Vertical direction

Claims (9)

1. A drying device for drying coal to obtain a moisture control coal having a predetermined moisture content;
   A coal gasification reactor which burns the moisture-regulating coal to produce hydrogen gas and carbon monoxide gas;
   The coal gasification reactor is
   Lower reaction vessel;
   An upper reaction vessel provided above the lower reaction vessel and in communication with the lower reaction vessel;
   A burner unit for supplying the moisture control coal and the oxygen-containing gas to the lower reaction vessel and burning the moisture control coal;
   A nozzle unit for supplying the moisture control coal to the upper reaction vessel;
   With coal gasification system.
2. A pressure measurement unit that measures a difference between the pressure in the furnace below the nozzle unit and the pressure in the furnace above the upper reaction vessel;
   A control unit that controls the drying device based on the pressure difference measured by the pressure measurement unit, and adjusts the amount of water contained in the coal;
   The coal gasification system according to claim 1, further comprising
3. A drying apparatus for drying subbituminous coal or lignite containing 20% or more of moisture by weight so that they have a predetermined moisture content to obtain moisture-adjusted coal;
   A coal gasification reactor that produces at least hydrogen gas and carbon monoxide gas by burning the moisture-regulating coal;
   Equipped with
   The coal gasification reactor is
   A lower reaction vessel in which a storage space is formed therein;
   An upper reaction vessel provided above the lower reaction vessel;
   Have
   The lower reaction vessel is
   It has a burner unit which supplies the moisture control coal and the oxygen-containing gas at a predetermined ratio without supplying steam to the lower reaction vessel, and burns the moisture control coal.
   The upper reaction vessel is
   A through hole which communicates with the storage space of the lower reaction vessel via a reduced diameter portion and extends in the vertical direction;
   A nozzle unit for supplying only the moisture control coal without supplying water vapor to the upper reaction vessel;
   Have
   The coal gasification system set to the quantity by which the steam and tar which generate | occur | produce from the said moisture content adjustment coal chemically react, and the said moisture content does not adhere in the said through-hole.
4. The coal gasification system according to claim 3, wherein the predetermined water content is 15% or more and 40% or less in mass ratio to the water content adjustment coal.
5. The coal gasification reactor is
   Pressure measurement for measuring the pressure difference between the internal pressure in the lower part of the through hole of the upper reaction vessel or the internal pressure in the accommodation space of the lower reaction vessel and the internal pressure of the upper end of the through hole Have a department,
   The coal gasification system according to claim 3 or 4 provided with a control part which controls said drying device and adjusts the amount of moisture which said coal has based on said pressure difference which said pressure measurement part measured.
6. A coal gasification method using the coal gasification system according to any one of claims 3 to 5,
   Drying the sub bituminous coal or lignite so as to have a predetermined water content to obtain the water content adjusting coal;
   The water content adjusting coal and the oxygen-containing gas are supplied to the lower reaction container without supplying water vapor from the burner part to burn the water content adjusting coal, and the water content from the nozzle part is supplied to the upper reaction container A chemical reaction process in which only the controlled amount of coal is supplied to chemically react the controlled amount of coal;
   Coal gasification method comprising.
7. In the chemical reaction process, at least carbon monoxide gas and hydrogen gas are produced by causing a chemical reaction between tar generated from the moisture control coal and steam generated by heating the moisture contained in the moisture control coal. The coal gasification method of Claim 6 which manufactures.
8. Drying the coal so as to contain a predetermined amount of water to obtain a moisture-regulating coal containing the predetermined amount of water;
   Supplying the moisture control coal and the oxygen-containing gas to the lower reaction vessel of the coal gasification reactor;
   Burning the moisture control coal inside the lower reaction vessel to generate a high temperature gas;
   Supplying the moisture controlled coal to an upper reaction vessel communicating with the lower reaction vessel of the coal gasification reactor;
   Heating the moisture regulating coal supplied to the upper reaction vessel with the high temperature gas flowing from the lower reaction vessel to the upper reactor;
   Coal gasification method comprising.
9. The coal gasification method according to claim 8, wherein at least one of sub bituminous coal and lignite is used as the coal.

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