AU2014202252A1

AU2014202252A1 - Coal gasification system and coal gasification combined cycle system

Info

Publication number: AU2014202252A1
Application number: AU2014202252A
Authority: AU
Inventors: Takuya Ishiga; Fumihiko Kiso; Fumihiko Nagaremori
Original assignee: Babcock Hitachi KK
Current assignee: Mitsubishi Power Ltd
Priority date: 2013-04-26
Filing date: 2014-04-24
Publication date: 2014-11-13
Anticipated expiration: 2034-04-24
Also published as: AU2014202252B2; JP2014214257A; JP6162468B2

Abstract

- 63 {Abstract} A coal gasification system comprising: a dryer for drying coal by combustion exhaust gas and permitting the combustion exhaust gas to contain moisture in the 5 coal; a gasifier for generating syngas that the coal is gasified; a dust remover for removing small particles in the syngas of the gasifier; a condensed heat exchanger for cooling the combustion exhaust gas after the coal is dried by the dryer and converting moisture 10 in the combustion exhaust gas to a liquid; a water recovery tower for leading the combustion exhaust gas via the condensed heat exchanger and the condensed water and recovering water from the combustion exhaust gas; a water feed system for leading the water 15 recovered from the combustion exhaust gas by the water recovery tower to the condensed heat exchanger, raising temperature by indirect heat exchange, and feeding it to the gasifier; and a shift reaction unit for leading the syngas with small particles removed by the dust 20 remover and steam, permitting carbon monoxide and steam in the syngas to perform a shift reaction, and converting them to carbon dioxide and hydrogen. z -ABSORPTION Lo 0 i. < coc U- L 0zo w

Description

Australian Patents Act 1990 - Regulation 3.2 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title Coal gasification and coal combined cycle system The following statement is a full description of this invention, including the best method of performing it known to me/us:- - la {DESCRIPTION} {Technical Field} The present invention relates to a coal gasification system for gasifying coal to obtain gas 5 containing carbon monoxide and hydrogen as main components and a coal gasification combined cycle system for generating power by a gas turbine using syngas produced by gasification of coal as fuel. {Background Art} 10 Coal is formed from ancient plants carbonized underground and is classified according to the carbonization degree (fixed carbon quantity) and volatile matter quantity. At present, most of coal used for coal-fired power 15 generation are classified as bituminous coal. The moisture contained in coal, although different from each other depending on the habitat even in the same bituminous coal, is mostly 10 wt% or lower. The coal kind lower in carbonization degree than 20 bituminous coal is called brown coal. The brown coal is more in the moisture content than bituminous coal and may contain about 50% of moisture depending on the coal kind. To perform high efficiency power generation in a 25 power generation plant using coal as fuel, it is - 2 necessary to pulverize coal by using a mill, though coal containing much moisture cannot be pulverized by the mill unless it is dried. When using coal containing much moisture such as 5 brown coal as fuel for a power generation plant after drying it, due to heat loss resulting from coal drying, the power generation efficiency of the power generation plant is reduced, so that even though brown coal is larger in the amount of reserves and lower in cost than 10 bituminous coal, brown coal was less used as fuel for a coal power generation plant. Therefore, for a coal-fired power generation plant using coal containing much moisture such as brown coal as fuel, various measures have been proposed to improve 15 the power generation efficiency. The technology described in Japanese Patent Laid open No. 2011-214814 (Patent Literature 1) shows a method of drying coal containing much moisture by a fluidized bed dryer. The fluidized bed is fluidized by 20 steam and to the fluidized bed, the heat for drying coal is fed via a heat exchanger tube. In the technology described in Patent Literature 1, even when feeding steam at about 200'C as a flow medium, the heat feed via the heat exchanger tube is necessary 25 because the quantity of heat necessary to vaporize - 3 moisture in coal is large and if no heat is fed via the heat exchanger tube, the temperature of the steam fed as a flow medium is reduced and the moisture is condensed. 5 In the Patent Literature 1, the moisture in coal can be converted to steam by the fluidized bed dryer, so that the converted steam is discharged from the fluidized bed dryer along with the steam used for fluidization and fed to a steam turbine, resulting in 10 that part of the heat used for drying can be collected as power. Further, since the steam discharged from the fluidized bed includes small particles of coal, dust removal is necessary before feeding the steam to the steam turbine. 15 The technology described in Japanese Patent Laid open No. 2010-106722 (Patent Literature 2) shows a high-efficiency power generation method using coal including much moisture as fuel by a coal gasification combined cycle system. 20 The coal gasification combined cycle system gasifies coal and uses syngas including the obtained carbon monoxide and hydrogen as fuel for a combined cycle system made up of a gas turbine and a steam turbine. 25 The coal-fired power generation widespread at - 4 present is coal boiler power generation where coal is completely burned by a boiler, the heating value is collected as steam, and then the steam turbine is driven by this steam to generate power. By contrast, 5 the coal gasification combined cycle system feeds the syngas generated from coal by the gasifier to the gas turbine as fuel, and the combustion temperature of the syngas at the gas turbine entrance is increased, thus a higher efficiency than the coal boiler power generation 10 can be realized. The technology described in the Patent Literature 2 collects the sensible heat of exhaust gas at the exit of the gas turbine as steam by the exhaust heat collection boiler and then uses it to dry coal 15 including much moisture. The temperature of the exhaust gas after the exhaust heat is collected by the exhaust heat collection boiler is approximately 100'C and in the conventional thermal power generation plant, the 20 exhaust gas has not been used effectively and if coal can be dried only by this exhaust gas, the power generation efficiency can be improved. However, only the quantity of heat possessed by the exhaust gas after the exhaust heat collection is 25 insufficient as the quantity of heat to dry the coal, - 5 so that the exhaust gas of the gas turbine before the exhaust heat collection is required to use and the improvement effect of the power generation efficiency is limited. 5 The syngas obtained by gasification of coal is not only used for power generation but also used as a raw material of synthesis of methanol, synthesized oil, and dimethyl ether. Depending on individual synthesis processes, 10 suitable hydrogen/carbon monoxide ratio in the syngas is different, so it is a widespread practice that a water gas shift reactor for permitting the carbon monoxide and steam contained in the syngas to react each other and promoting the shift reaction for 15 converting to carbon dioxide and hydrogen is installed so as to adjust the suitable hydrogen/carbon monoxide ratio in the syngas. The shift reaction requires a catalyst and the water gas shift reactor mentioned above is filled with 20 a shift reaction catalyst. Although depending on the property of the shift reaction catalyst, to progress the shift reaction, steam 1.2 to 2 times the carbon monoxide in the syngas is necessary, and steam must be produced by heating industrial water. 25 Further, even when burning the syngas obtained by - 6 gasifying coal as fuel and using it for power generation of the gas turbine, to reduce the carbon dioxide discharge rate and prevent the global warning, before burning the syngas by the gas turbine, it is 5 necessary to convert carbon monoxide and steam to carbon dioxide and hydrogen by the shift reaction, remove the converted carbon dioxide, then feed the syngas including the hydrogen to the gas turbine as fuel, and then burn it. 10 To increase the collection rate of carbon dioxide included in the syngas obtained by gasifying coal to 90% or higher, although depending on the coal kind, to feed steam used for the shift reaction, industrial water on the same level as the coal weight is necessary. 15 {Citation List} {Patent Literaturel {Patent Literature 11 Japanese Patent Laid-open No. 2011-214814 {Patent Literature 2} Japanese Patent Laid-open No. 20 2010-106722 {Summary of Invention} {Technical Problem} To adjust the hydrogen/carbon monoxide ratio of the syngas obtained by gasification of coal, a shift 25 reaction for permitting the carbon monoxide and steam in the syngas to react and converting them to carbon dioxide and hydrogen is necessary and a problem arises that to obtain steam necessary to the shift reaction, a large quantity of industrial water is required. 5 The technology disclosed in the Japanese Patent Laid-open No. 2011-214814 collects the heat used to dry coal by the steam turbine. However, this technology must feed heat for vaporizing the moisture discharged from the coal to an overheat state from the outside. 10 The steam temperature at the exit of the fluidized bed dryer for drying coal is about 200'C at its maximum and even if the steam is fed to the steam turbine, the conversion efficiency to the electric power by the steam turbine is low, so that a problem arises that the 15 heat loss is increased. Further, in the technology disclosed in the Japanese Patent Laid-open No. 2010-106722, the exhaust gas of the gas turbine after the exhaust heat collection which is not used is used to dry the coal, 20 thus a certain degree of improvement effect of the power generation efficiency is obtained, though only by the exhaust gas after the exhaust heat collection, the quantity of heat necessary to dry coal cannot be obtained, so that the exhaust gas of the gas turbine 25 before the heat collection must be added.

- 8 However, this technology discharges the exhaust gas after coal drying into the atmosphere, so that the heat used for drying cannot be collected and the power generation efficiency improvement effect is possibly 5 limited. Furthermore, the moisture included in coal is discharged into the atmosphere and is not used effectively, so that the heat collection and moisture recovery from the exhaust gas after coal drying are problems to be solved. 10 An object of the present invention is to provide a coal gasification system and a coal gasification combined cycle system capable of adjusting the carbon monoxide-hydrogen ratio in the syngas generated by the gasifier due to the shift reaction of the shift 15 reaction unit and improving the plant efficiency. {Solution to Problem} A coal gasification system of the present invention comprising: a dryer for drying coal by combustion exhaust gas and permitting the combustion exhaust gas 20 to contain moisture in the coal in a gas state, a gasifier for feeding the coal dried by the dryer and an oxidizing agent, permitting the coal to react with the oxidizing agent, and generating gasified syngas, a dust remover installed on a downstream side of the gasifier 25 for removing small particles in the syngas fed from the - 9 gasifier, a condensed heat exchanger installed on the downstream side of the dryer for cooling the combustion exhaust gas after the coal is dried by the dryer and converting moisture in the combustion exhaust gas to a 5 liquid, a water recovery tower installed on a downstream side of the condensed heat exchanger for leading the combustion exhaust gas via the condensed heat exchanger and water condensed by the condensed heat exchanger and recovering the water from the 10 combustion exhaust gas, a water feed system arranged so as to lead the water recovered from the combustion exhaust gas by the water recovery tower to the condensed heat exchanger, permit indirect heat exchange with the combustion exhaust gas to raise temperature, 15 and feed the water raised in temperature by the condensed heat exchanger to the gasifier or a downstream side of the gasifier, and a shift reaction unit installed on a downstream side of the dust remover for leading the syngas removed the small particles by 20 the dust remover and steam, permitting carbon monoxide and steam in the syngas to perform a shift reaction, and converting them to carbon dioxide and hydrogen. A coal gasification combined cycle system of the present invention comprising: a dryer for drying coal, 25 a gasifier for permitting the coal dried by the dryer - 10 and an oxidizing agent to react and generating gasified syngas, a shift reaction unit installed on a downstream side of the gasifier for permitting carbon monoxide and steam in the syngas generated by the gasifier to 5 perform a shift reaction and converting them to carbon dioxide and hydrogen, a gas cleanup unit installed on a downstream side of the shift reaction unit for removing a sulfur compound and others from the syngas after the shift reaction, and a gas turbine unit for burning the 10 syngas cleaned-up by the gas cleanup unit as fuel to generate power, characterized in that, the dryer is structured so as to feed combustion exhaust gas discharged from a gas turbine of the gas turbine unit, dry the coal in the dryer, permit the combustion 15 exhaust gas to contain moisture in the coal, and feed the dried coal to the gasifier which is gasified by permitting the dried coal to react with an oxidizing agent, a first dust remover is installed on a downstream side of the gasifier for removing small 20 particles in the syngas fed from the gasifier, a second dust remover is installed on a downstream side of the dryer for removing small particles included in the combustion exhaust gas discharged from the dryer, and a condensed heat exchanger is installed on a downstream 25 side of the dust remover for drying the coal by the - 11 dryer, then cooling the combustion exhaust gas, and converting moisture in the combustion exhaust gas to a liquid, a water recovery tower is installed on a downstream side of the condensed heat exchanger for 5 leading the combustion exhaust gas via the condensed heat exchanger and the water condensed by the condensed heat exchanger and recovering the water from the combustion exhaust gas, a first water feed system is arranged so as to lead the water recovered from the 10 combustion exhaust gas by the water recovery tower to the condensed heat exchanger, perform indirect heat exchange with the combustion exhaust gas to raise temperature, and feed the water raised in temperature by the condensed heat exchanger to a unit positioned on 15 the downstream side of the gasifier, a second water feed system is arranged so as to branch the water recovered from the combustion exhaust gas by the water recovery tower from the first water feed system and feed it to a humidifier for humidifying air which is 20 pressurized by a gas turbine compressor of the gas turbine unit and is fed to a gas turbine combustor, and a shift reaction unit is installed on the downstream side of the dust remover for leading the syngas removed the small particles by the dust remover, permitting 25 carbon monoxide and steam in the syngas to perform the - 12 shift reaction, and converting them to carbon dioxide and hydrogen. Further, A coal gasification combined cycle system of the present invention comprising: a dryer for drying 5 coal, a gasifier for permitting the coal dried by the dryer and an oxidizing agent to react and generating gasified syngas, a shift reaction unit installed on a downstream side of the gasifier for permitting carbon monoxide and steam in the syngas generated by the 10 gasifier to perform to a shift reaction and converting them to carbon dioxide and hydrogen, a gas cleanup unit installed on a downstream side of the shift reaction unit for removing a sulfur compound and others from the syngas after the shift reaction, and a gas turbine unit 15 for burning the syngas cleaned-up by the gas cleanup unit as fuel to generate power, characterized in that, the dryer is structured so as to feed the combustion exhaust gas discharged from a gas turbine of the gas turbine unit, dries the coal in the dryer, permit the 20 combustion exhaust gas to include moisture in the coal, and feed the dried coal to the gasifier which is gasified by permitting the dried coal to react with an oxidizing agent, a first dust remover is installed on a downstream side of the gasifier for removing small 25 particles in the syngas fed from the gasifier, a second - 13 dust remover is installed on a downstream side of the dryer for removing small particles included in the combustion exhaust gas discharged from the dryer, a first condensed heat exchanger is installed on a 5 downstream side of the second dust remover for drying the coal by the dryer, then cooling the combustion exhaust gas, and converting moisture in the combustion exhaust gas to a liquid, a first water recovery tower is installed on a downstream side of the first 10 condensed heat exchanger for leading the combustion exhaust gas via the first condensed heat exchanger and water condensed by the first condensed heat exchanger and recovering water from the combustion exhaust gas, a first water feed system is arranged so as to lead 15 the water recovered from the combustion exhaust gas by the first water recovery tower to the first condensed heat exchanger, perform indirect heat exchange with the combustion exhaust gas to raise temperature, and feed the water raised in temperature by the first condensed 20 heat exchanger to a cooling tower installed on the downstream side of the gasifier for cooling the syngas generated by the gasifier, a second condensed heat exchanger for branching and leading the combustion exhaust gas discharged from the gas turbine of the gas 25 turbine unit on an upstream side of the dryer, cooling - 14 the branched and led combustion exhaust gas, and converting the moisture in the combustion exhaust gas to a liquid, a second water recovery tower is installed on a downstream side of the second condensed heat 5 exchanger for recovering water from the combustion exhaust gas via the second condensed heat exchanger, a second water feed system is arranged so as to lead the water recovered from the combustion exhaust gas by the second water recovery tower to the second condensed 10 heat exchanger, perform indirect heat exchange with the combustion exhaust gas to raise temperature, and feed the water raised in temperature by the second condensed heat exchanger to a humidifier for humidifying air which is pressurized by the gas turbine compressor of 15 the gas turbine unit and is fed to the gas turbine combustor, and a shift reaction unit is installed on the downstream side of the first dust remover for leading the syngas removed the small particles by the first dust remover and steam , permitting carbon 20 monoxide and steam in the syngas to perform the shift reaction, and converting them to carbon dioxide and hydrogen. {Advantageous Effects of Invention} According to the present invention, a coal 25 gasification system and a coal gasification combined - 15 cycle system including the coal gasification system capable of adjusting the carbon monoxide and hydrogen ratio in the syngas generated by the gasifier due to the shift reaction of the shift reaction unit and 5 improving the plant efficiency can be realized. {Brief Description of Drawings} {Fig. 11 Fig. 1 is a schematic block diagram showing a coal gasification system, which is a first embodiment of the present invention, having a 10 constitution of feeding moisture recovered from coal to the gasifier, which is a gasification system for gasifying coal including much moisture. {Fig. 2} Fig. 2 is a schematic block diagram showing a coal gasification system, which is a second 15 embodiment of the present invention, having a constitution of feeding moisture recovered from coal to the cooling tower on the downstream side of the gasifier, which is a gasification system for gasifying coal including much moisture. 20 {Fig. 31 Fig. 3 is a schematic block diagram showing a coal gasification combined cycle system, which is a third embodiment of the present invention, for generating power by the gas turbine using syngas obtained by gasifying coal including much moisture as 25 fuel.

- 16 {Fig. 4} Fig. 4 is a schematic block diagram showing a coal gasification combined cycle system, which is a fourth embodiment of the present invention, having a constitution of feeding moisture recovered 5 from coal to the cooling tower on the downstream side of the gasifier, which is a coal gasification combined cycle system for generating power by the gas turbine using the syngas obtained by gasifying coal including much moisture as fuel. 10 {Fig. 51 Fig. 5 is a schematic block diagram showing a coal gasification combined cycle system, which is a fifth embodiment of the present invention, having a constitution that the system for recovering moisture from the exhaust gas of the gas turbine as a 15 liquid is made up of two systems of a system for drying coal and then leading it to condensed heat exchange and a system for leading to another condensed heat exchange, which is a coal gasification combined cycle system for generating power by the gas turbine using the syngas 20 obtained by gasifying coal including much moisture as fuel. {Fig. 6} Fig. 6 is a schematic block diagram showing a coal gasification combined cycle system, which is a sixth embodiment of the present invention, 25 having a constitution that two or more coal dryers are - 17 installed, which is a coal gasification combined cycle system for generating power by the gas turbine using the syngas that coal including much moisture is gasified as fuel. 5 {Description of Embodiments} The coal gasification system and coal gasification combined cycle system which are embodiments of the present invention will be explained by referring to the drawings. 10 {Embodiment 11 The coal gasification system which is the first embodiment of the present invention will be explained by referring to Fig. 1. In the coal gasification system of this embodiment 15 shown in Fig. 1, coal 1 including moisture as fuel is dried by a dryer 40 of a type of direct contact with combustion exhaust gas 14 discharged from the gas turbine (not shown). The coal 1 dried by the dryer 40 is fed to a 20 gasifier 50 installed on the downstream side of the dryer 40, and the coal 1 is permitted to react with an oxidizing agent 2 such as oxygen fed to the gasifier 50 from the outside, and the gasifier 50 generates syngas 20 having main components of carbon monoxide and 25 hydrogen.

- 18 Here, the combustion exhaust gas 14 fed to the dryer 40 dries the coal 1, then becomes exhaust gas 14a discharged from the exit of the dryer 40, and is fed to the gasifier 50, though moisture 14d recovered by the 5 dryer 40 is also fed from the dryer 40 to the gasifier 50. Further, the dryer 40 dries the coal 1 and in the exhaust gas 14a discharged from the exit of the dryer 40, the moisture included in the coal 1 is included as 10 steam 14c. Therefore, the exhaust gas 14a including the steam 14c is led to the condensed heat exchanger 70 installed on the downstream side of the dryer 40 and is cooled, and part of the steam 14c in the exhaust gas 14a is 15 condensed and is led to a water recovery tower 65 installed on the downstream side of the condensed heat exchanger 70 and is recovered. Furthermore, the residual steam 14c in the exhaust gas 14a which was not condensed by the condensed heat 20 exchanger 70 is led to the water recovery tower 65 together with the exhaust gas 14a and liquid water 10 fed from the outside is sprayed into the water recovery tower 65, and a large part of residual steam 14c in the exhaust gas 14a is condensed and is recovered by the 25 water recovery tower 65 as liquid water 14b.

- 19 The water 14b recovered from the exhaust gas 14a by the water recovery tower 65 is fed to the condensed heat exchanger 70 from the water recovery tower 65, is raised in temperature by indirect heat exchange with 5 the exhaust gas 14a, and is fed to the gasfier 50 through a water feed system 15 via the condensed heat exchanger 70, though it is heated to steam by the sensible heat of syngas 20 generated by the gasifier 50. And, the syngas 20 including the steam is fed to a 10 dust remover 53 installed on the downstream side of the gasifier 50, becomes the syngas 20 cleaned up by removing non-reacted coal particles included in the syngas 20 by the dust remover 53, and is fed to a shift reactor 55 installed on the downstream side of the dust 15 remover 53. The shift reactor 55 permits carbon monoxide and steam 12 in the syngas 20 to perform the shift reaction

(H

2 0 + CO -+ CO 2 + H 2 ) to convert them to carbon dioxide and hydrogen. 20 Here, when the steam-carbon monoxide ratio in the syngas 20 is smaller than the value necessary to obtain the target carbon monoxide conversion ratio, on the entrance side of the shift reactor 55, the steam 12 is fed into the syngas 20 so that the steam-carbon 25 monoxide ratio in the syngas 20 reaches the target - 20 value. In the coal gasification system for generating power using coal including much moisture as fuel, the heat loss for drying coal is large, though according to 5 the coal gasification system of this embodiment, the heat used for coal drying can be recovered as sensible heat of the syngas in the gasifier or at the exit of the cooling tower. Further, when adjusting the hydrogen/carbon 10 monoxide ratio in the syngas in the coal gasification system, to realize the shift reaction of the syngas, though depending on the property of the shift reaction catalyst, a large quantity of industrial water on the same level as the mass of the carbon in the coal is 15 necessary, while according to the coal gasification system of this embodiment, the moisture possessed by the coal can be given to the syngas, so that the industrial water becomes unnecessary and the running cost can be reduced extensively. 20 As mentioned above, according to this embodiment, a coal gasification system capable of adjusting the carbon-monoxide and hydrogen ratio in the syngas generated by the gasifier due to the shift reaction of the shift reaction unit and improving the plant 25 efficiency can be realized.

- 21 {Embodiment 2} Next, the coal gasification system which is the second embodiment of the present invention will be explained by referring to Fig. 2. 5 The coal gasification system of this embodiment shown in Fig. 2 is the same in the basic constitution as the coal gasification system of the first embodiment shown in Fig. 1, so that the explanation of the constitution common to the two is omitted and only the 10 different constitution will be explained below. In the coal gasification system of the first embodiment shown in Fig. 1, the liquid water recovered from the combustion exhaust gas is fed to the gasifier 50, whereas the coal gasification system of this 15 embodiment shown in Fig. 2 is so structured that a cooling tower 52 is installed in a position on the downstream side of the gasifier 50 and on the upstream side of the dust remover 53, the syngas 20 generated in the gasifier 50 is fed to this cooling tower 52, and 20 the syngas 20 is cooled by the cooling tower 52. The coal gasification system of this embodiment is structured so that the water 14b recovered from the exhaust gas 14a by the water recovery tower 65 is fed to the condensed heat exchanger 70 from the water 25 recovery tower 65, is raised in temperature by indirect - 22 heat exchange with the exhaust gas 14a, and is fed to the cooling tower 52 on the downstream side of the gasifier 50 through a water feed system 17 via the condensed heat exchanger 70, and by the cooling tower 5 52, the syngas 20 fed from the gasifier 50 is cooled. And, the syngas 20 cooled by the cooling tower 52 is fed to the dust remover 53, and by the dust remover 53, non-reacted coal particles included in the syngas 20, which are fed from the gasifier 50 via the cooling 10 tower 52, are removed and cleaned up, and the cleaned up syngas 20 is fed to the shift reactor 55 installed on the downstream side of the dust remover 53. And, the system is structured so that the steam 12 is also fed to the shift reactor 55 from the outside. 15 The liquid water 14b fed to the cooling tower 52 from the water recovery tower 65 through the water feed system 17 via the condensed heat exchanger 70, similarly to the case of the liquid water 14b fed to the gasifier 50 from the water recovery tower 65 of the 20 coal gasification system of the first embodiment through the water feed system 15 via the condensed heat exchanger 70, becomes steam due to the sensible heat of the syngas 20 by the cooling tower 52. In the coal gasification system for generating 25 power using coal including much moisture as fuel, the - 23 heat loss for drying coal is large, though according to the coal gasification system of this embodiment, the heat used for coal drying can be recovered as sensible heat of the syngas in the gasifier or at the exit of 5 the cooling tower. Further, when adjusting the hydrogen/carbon monoxide ratio in the syngas in the coal gasification system, to realize the shift reaction of the syngas, though depending on the property of the shift reaction 10 catalyst, a large quantity of industrial water on the same level as the mass of the carbon in the coal is necessary, while according to the coal gasification system of this embodiment, the moisture possessed by the coal can be given to the syngas, so that the 15 industrial water becomes unnecessary and the running cost can be reduced extensively. As mentioned above, according to this embodiment, a coal gasification system capable of adjusting the carbon-monoxide and hydrogen ratio in the syngas 20 generated by the gasifier due to the shift reaction of the shift reaction unit and improving the plant efficiency can be realized. {Embodiment 31 Next, the coal gasification combined cycle system 25 which is the third embodiment of the present invention - 24 will be explained by referring to Fig. 3. In the coal gasification combined cycle system of this embodiment shown in Fig. 3, the coal 1 including moisture as fuel is fed to and dried by the dryer 40 of 5 a type of direct contact with the combustion exhaust gas 14 discharged from the gas turbine 62 composing the gas turbine unit. The coal 1 dried by direct contact with the combustion exhaust gas 14 discharged from the gas 10 turbine 62 by the dryer 40 is finely pulverized by a mill not drawn, then is transported by nitrogen N 2 which is coal transport gas 3, and is fed to the gasifier 50. In the gasifier 50, the fed coal 1 is permitted to react with the oxidizing agent 2 such as oxygen which 15 is fed to the gasifier 50 from the outside and is gasified and the syngas 20 having main components of carbon-dioxide and hydrogen is generated. Here, the gasifier 50 is operated at high temperature and the ash included in the coal 1 is 20 discharged outside from the gasifier 50 as melting slag 5. The combustion exhaust gas 14 used to dry the coal 1 by the dryer 40 is discharged from the exit of the dryer 40 on the downstream side of the dryer 40 as 25 exhaust gas 14a, and the moisture 14d recovered from - 25 the exhaust gas 14 by the dryer 40 is fed to the gasifier 50 together with the nitrogen N 2 of the coal transport gas 3. In the coal gasification combined cycle system of 5 this embodiment, on the downstream side of the dryer 40, the water recovery tower 65 for recovering water from the combustion exhaust gas 14a is installed, and the steam 14c included in the combustion exhaust gas discharged from the exit of the dryer 40 is cooled by 10 the condensed heat exchanger 70 installed on the downstream side of the dryer 40 and is led to the water recovery tower 65, and the liquid water 10 fed to the water recovery tower 65 from the outside is sprayed, and a large part of residual steam 14c in the exhaust 15 gas 14a is condensed and is recovered by the water recovery tower 65 as liquid water 14b. The water 10 feed rate to the water recovery tower 65 for feeding the water 10 to the water recovery tower 65 from the outside is adjusted by measuring the water 20 surface level of the water recovery tower 65 by a level gauge 91 and on the basis of the measured value measured by the level gauge 91, by operating the switching of a flow rate adjustment valve 81 for feeding the water 10 to the water recovery tower 65. 25 Gas generated by the water recovery tower 65 is - 26 discharged from a chimney 66 into the atmosphere. In the coal gasification combined cycle system of this embodiment, the water 14b included in combustion exhaust gas 20a is recovered by the water recovery 5 tower 65 and from the water recovery tower 65 and through the water feed system 15, the water 14b is fed to a heat collection portion 51 of the gasifier 50, though the water 14b fed from the water recovery tower 65 through the water feed system 15 is sprayed and fed 10 at several stages to the heat collection portion 51 which is positioned on the downstream side of the reaction portion of the gasifier 50 and is integrated with the gasifier 50, and in the heat recovery portion 51, the syngas 20 generated in the gasifier 50 and the 15 water 14b sprayed at several stages make direct contact with each other. In the coal gasification system provided in the coal gasification combined cycle system of this embodiment, a coal gasification system having the same 20 basic constitution as that of the first embodiment shown in Fig. 1 is used. The feed rate of the water 14b fed from the water recovery tower 65 through the water feed system 15 to the heat collection portion 51 of the gasifier 50, in 25 the water gas shift reactor 55 installed on the - 27 downstream side of the gasifier 50 and the dust remover 53, is adjusted so that the steam/carbon monoxide ratio in the syngas 20 is set within the range necessary to obtain the target carbon monoxide conversion ratio. 5 Namely, a plant information-operation target 87 such as the coal feed rate and oxygen feed rate to the gasifier 50, the performance of the shift reaction catalyst filled in the shift reactor 55, and the target carbon monoxide conversion ratio is inputted into a 10 control unit 86 and the control unit 86 calculates respectively the flow rate and the steam/carbon monoxide ratio of the exit gas of the gasifier 50 and the steam concentration /carbon monoxide ratio necessary at the entrance of the water gas shift 15 reactor 55, obtains the necessary feed rate of the water 14b using these calculated values, and so as to be able to feed the feed rate of the water 14b to the heat collection portion 51 of the gasifier 50, on the basis of an operation signal outputted from the control 20 unit 86, the switching of a flow rate adjustment valve 80 installed in the water feed system 15 is controlled, and the feed rate of the water 14b fed from the water recovery tower 65 through the water feed system 15 to the heat collection portion 51 of the gasifier 50 is 25 adjusted.

- 28 Further, if the syngas 20 generated by the gasifier 50 and the water 14b make direct contact with each other, the temperature of the syngas 20 is lowered. To prevent moisture from condensing at the dust remover 53 5 installed on the downstream side of the gasifier 50, the temperature of the dust remover 53 on the entrance side must be kept at the regulated value or higher, so that on the entrance side of the dust remover 53 installed on the downstream side of the gasifier 50, a 10 thermometer 90 is installed and the temperature of the syngas 20 on the entrance side of the dust remover 53 which is detected by the thermometer 90 is inputted to the control unit 86, and by the control unit 86, the switching of the flow rate adjustment valve 80 is 15 controlled, thus so that the temperature of the syngas 20 on the entrance side of the dust remover 53 which is detected by the thermometer 90 is maintained within the range not lower than the regulated value, the feed rate of the water 14b which is recovered by the water 20 recovery tower 65 and is fed to the heat collection portion 51 of the gasifier 50 from the water recovery tower 65 through the water feed system 15 is adjusted. As mentioned above, to the heat collection portion 51 which is positioned on the downstream side of the 25 reaction portion of the gasifier 50 and is integrated - 29 with the gasifier 50, the water 14b is sprayed at several stages and is fed into the syngas 20, thus the syngas 20 generated in the gasifier 50 is prevented from local reduction in temperature. 5 Further, a local low-temperature position is prevented from an occurrence in the syngas 20, thus the sprayed water 14b is gasified immediately and non reacted char in the syngas 20 is prevented from condensation due to existence of liquid water. 10 The water 14b fed to the heat collection portion 51 on the downstream side of the gasifier 50 from the water recovery tower 65 through the water feed system 15 at several stages becomes steam due to the sensible heat of the syngas 20. 15 Syngas 16 including this steam is fed to a knockout drum 57 installed on the downstream side of the heat collection portion 51 from the heat collection portion 51 on the downstream side of the gasifier 50 and after removing moisture remaining in a liquid state, is fed 20 to the dust remover 53 installed on the downstream side of the knockout drum 57. The dust remover 53 collects and removes non reacted coal particles called char 6 included in the syngas 16. The char 6 collected from the dust remover 25 53 is transported to the gasifier 50 by the nitrogen 4, - 30 so that the dust remover 53, as mentioned above, is structured so as to return the non-reacted coal particles to the gasifier 50, so that in the coal gasification combined cycle system of this embodiment, 5 the coal use efficiency can be improved. Here, a part of the liquid water 14b recovered by the water recovery tower 65, as mentioned above, is fed to the heat collection portion 51 on the downstream side of the gasifier 50 from the water recovery tower 10 65 via the condensed heat exchanger 70 through the water feed system 15, though the remainder of the liquid water 14b recovered by the water recovery tower 65 humidifies air compressed by a gas turbine compressor 61, so that through a water branch system 15 15b branching halfway the water feed system 15 for feeding the water 14b to the condensed heat exchanger 70 from the water recovery tower 65, a part of the water 14b is fed to a humidifying tower 64 installed on the downstream side of the gas turbine compressor 61. 20 And, the air compressed by the gas turbine compressor 61 which is humidified by feeding the water 14b to the humidifying tower 64, to perform indirect heat exchange with the combustion exhaust gas 14 discharged from a gas turbine 62, is led to a heat 25 exchanger 74 positioned on the downstream side of the - 31 humidifying tower 64 and on the upstream side of a gas turbine combustor 60, raises the air humidified by the heat exchanger 74 in temperature by the combustion exhaust gas 14 discharged from the gas turbine 62, then 5 is fed to the gas turbine combustor 60, is burned by the gas turbine combustor 60 together with the hydrogen fuel which is syngas 13 after the shift reaction by the water gas shift reactor 55, generates the high temperature combustion gas 14 and drives the gas 10 turbine 62. The gas turbine 62 drives the gas turbine compressor 61 and a gas turbine generator 63 and generates power by the gas turbine generator 63. The syngas 16 after dust removed by the dust 15 remover 53 is fed to a water washing tower 54 installed on the downstream side of the dust remover53 on the downstream side of the knockout drum 57 and by water 8 fed to the water washing tower 54 from the outside, halogen and others in the syngas 16 are washed and 20 removed, and the cleaned-up syngas 16 is raised in temperature via the heat exchanger 71 installed on the downstream side of the water washing tower 54 and then is fed to the shift reactor 55 installed on the downstream side of the water washing tower 54. 25 The syngas 16 generated by the gasifier 50 is - 32 removed dust by the dust remover 53 and then passes through the water washing tower 54, thus the temperature of the syngas 16 is lowered, though the syngas 16 washed by the water washing tower 54 is 5 permitted to flow down into a heat exchanger 71 as a heat source, and indirect heat exchange is performed between the syngas 16 before flowing into the water washing tower 54 and the heat exchanger 71 to raise the temperature, thus the heat loss of the syngas 16 is 10 reduced. The syngas 16 washed by the water washing tower 54 is raised in temperature by the heat exchanger 71 and then is fed to the shift reactor 55 installed on the downstream side of the water washing tower 54 and by 15 the shift reactor 55, the carbon monoxide and steam in the syngas 16 are performed a shift reaction and are converted to carbon dioxide and hydrogen. And, when the steam/carbon monoxide ratio in the syngas 16 at the entrance of the shift reactor 55 is 20 smaller than the value necessary to obtain the target carbon monoxide conversion ratio, the feed rate of the steam 12 fed into the syngas 16 from the outside on the entrance side of the shift reactor 55 is increased. The syngas 13 after the shift reaction by the shift 25 reactor 55 is fed to an absorption tower 56 composing a - 33 gas cleanup unit for removing a sulfur compound from the syngas 13 and in the absorption tower 56 installed on the downstream side of the shift reactor 55, the syngas 13 is made contact with an absorption liquid 11 5 having a main component, for example, methyl diethanol amine, and a sulfur compound such as hydrogen sulfide included in the syngas 13 and carbon dioxide are removed, thus the syngas 13 including hydrogen as fuel is generated. 10 The temperature of the syngas 13 at the exit of the shift reactor 55 is 200 to 300'C, while the operation temperature of the absorption tower 56 is approximately 40'C, and the syngas 13 passes through the absorption tower 56, thus the temperature of the syngas 13 is 15 lowered. Therefore, the syngas 13 at the exit of the shift reactor 55, by a heat exchanger 73 positioned on the downstream side of the shift reactor 55 and on the upstream side of the absorption tower 56, is subjected 20 to indirect heat exchange with the syngas 13 at the exit of the absorption tower 56 to lower the temperature, and the heat of the syngas 13 at the exit of the shift reactor 55 is given to the syngas 13 at the exit of the absorption tower 56, thus the heat loss 25 of the syngas 13 is prevented.

- 34 Further, the temperature of the syngas 13 at the exit of the shift reactor 55, even after passing through the heat exchanger 73, is higher than the operation temperature of the absorption tower 56, so 5 that the system is structured so as to cool the syngas 13 by the heat exchanger 73 and then permit it to pass through the absorption tower 56. The syngas 13 including the hydrogen, in which the sulfur compound included in the syngas 13 removed by 10 the absorbing liquid 11 in the absorption tower 56 is raised in temperature by the heat exchanger 72 positioned on the downstream side of the shift reactor 55 and on the upstream side of the absorption tower 56 from the absorption tower 56, is fed to the gas turbine 15 combustor 60 composing the gas turbine unit as fuel, is burned by the gas turbine combustor 60, generates the high-temperature combustion exhaust gas 14, and drives the gas turbine 62 by the combustion exhaust gas 14. The gas turbine 62 drives the gas turbine 20 compressor 61 and the gas turbine generator 63 and generates power by the gas turbine generator 63. In the gas turbine combustor 60, air 26 for burning the syngas 13 of fuel including the hydrogen fed to the gas turbine combustor 60 is taken in from the 25 atmosphere by the gas turbine compressor 61 and is - 35 pressurized. On the entrance side of the gas turbine compressor 61, liquid spray water 9 is sprayed into the air 26 and the heat generated when the air 26 is compressed by the 5 gas turbine compressor 61 is used to gasify the spray water 9, and the temperature rise of the air 26 is prevented, and the heat loss in correspondence with compression is prevented. The syngas 16 after dust removal by the dust 10 remover 53 removes halogen by the water washing tower 54 and is fed to the shift reactor 55. When the syngas 16 after dust removal passes through the water washing tower 54, the temperature of the syngas 16 is lowered, so that indirect heat exchange is performed between the 15 syngas 16 of the exit gas of the water washing tower 54 and the syngas 16 after removed dust by the dust remover 53 at the heat exchanger 71, thus the heat loss is reduced. When the steam/carbon monoxide ratio in the syngas 20 16 at the entrance of the shift reactor 55 is smaller than the value necessary to obtain the target carbon monoxide conversion ratio, at the entrance of the shift reactor 55, the steam 12 is fed from the outside at the entrance of the shift reactor 55. 25 The syngas 13 after the shift reaction by the shift - 36 reactor 55 is fed to the absorption tower 56 and is made contact with the absorption liquid 11 having a main component of, for example, methyl diethanol amine, thus a sulfur compound such as hydrogen sulfide and 5 carbon dioxide are removed. The temperature of the syngas 13 at the exit of the shift reactor 55 is 200 to 300'C, while the operation temperature of the absorption tower 56 is approximately 40'C, and the syngas 13 passes through the absorption 10 tower 56, thus the temperature of the syngas 13 is lowered, so that the syngas 13 at the exit of the shift reactor 55 is subjected to indirect heat exchange with the syngas at the exit of the absorption tower 56 and the heat of the syngas at the exit of the shift reactor 15 55 is given to the syngas at the exit of the absorption tower 56, thus the heat loss is prevented. Further, the temperature of the syngas at the exit of the shift reactor 55 is higher than the operation temperature of the absorption tower 56 even after 20 passing through the heat exchanger 73, so that the syngas is cooled by the heat exchanger 73 and then passes through the absorption tower 56. The syngas 13 in which the sulfur compound removed by the absorption tower 56 is fed to the gas turbine 25 combustor 60 as fuel. The air 26 for burning the syngas - 37 13 is pressurized by the gas turbine compressor 61. At the entrance of the gas turbine compressor 61, the liquid spray water 9 is sprayed and the heat generated when the air 26 is compressed by the gas 5 turbine compressor 61 is used for gasifying the spray water 9, so that the temperature rise of the air 26 is prevented and the heat loss in correspondence with compression is prevented. The coal gasification combined cycle system of this 10 embodiment is structured, in the dryer 40 for drying the coal 1 by using the combustion exhaust gas 14 of the gas turbine, regarding the recovery of the moisture included in the combustion exhaust gas 14a discharged from the exit of the dryer 40, so as to firstly lead 15 the exhaust gas 14a to a dust remover 41 installed on the downstream side of the dryer 40, remove small particles of coal scattered into the exhaust gas 14a, next lead the exhaust gas 14a to the condensed heat exchanger 70 installed on the downstream side of the 20 dust remover 41 and cool it, thereby condense a part of the steam in the exhaust gas 14a, furthermore, lead the exhaust gas 14a to the water recovery tower 65 installed on the downstream side of the condensed heat exchanger 70, permit the liquid water 10 sprayed from 25 the outside to the water recovery tower 65 and the - 38 exhaust gas 14a to make contact with each other by the water recovery tower 65, thus condense a large part of the residual steam in the exhaust gas 14a, and recover it as liquid water 14b. 5 Further, the water feed rate of the water 10 to the water recovery tower 65 which is fed the water 10 from the outside is controlled by measuring the water surface level of the water recovery tower 65 by a level gauge 91 and so that the measured value by the level 10 gauge 91 enters the regulated range, operating the switching of the flow rate adjustment valve 81 for feeding the water 10 to the water recovery tower 65. In the coal gasification combined cycle system for generating power using coal including much moisture as 15 fuel, the heat loss for drying coal is large, though according to this embodiment, the heat used for coal drying can be collected as sensible heat of the syngas in the gasifier or at the exit of the cooling tower. In the coal gasification combined cycle system of 20 this embodiment, the steam in the syngas, in the shift reactor on the downstream side, reacts with carbon monoxide and is converted to hydrogen and carbon dioxide, so that even when the gas is lowered in temperature and is cleaned up on the downstream side of 25 the shift reactor, the heat loss due to condensation of - 39 the steam is small and a large part of the heat used for coal drying can be given to the power generation by the gas turbine. And, the temperature of the combustion gas at the 5 gas turbine entrance can be set at 1300'C to 1500'C and at a higher temperature than the power generation by the steam turbine using steam at approximately 200'C, the thermal cycle can be driven, so that the efficiency is high and the heat loss can be reduced excessively. 10 Further, when adjusting the hydrogen/carbon monoxide ratio in the syngas in the coal gasification system or in a carbon dioxide collection type coal gasification combined cycle system, to perform the shift reaction for the syngas, though depending on the 15 property of the shift catalyst, a large quantity of industrial water on the same level as the mass of carbon in the coal is necessary, while according to this embodiment, the moisture possessed by the coal can be given to the syngas, so that the industrial water is 20 unnecessary and the running cost can be reduced excessively. As mentioned above, according to this embodiment, a coal gasification combined cycle system capable of adjusting the carbon-monoxide and hydrogen ratio in the 25 syngas generated by the gasifier due to the shift - 40 reaction of the shift reaction unit and improving the plant efficiency can be realized. {Embodiment 4} Next, the coal gasification combined cycle system 5 which is the fourth embodiment of the present invention will be explained by referring to Fig. 4. The coal gasification combined cycle system of this embodiment shown in Fig. 4 is the same in the basic constitution as the coal gasification combined cycle 10 system of the third embodiment shown in Fig. 3, so that the explanation of the constitution common to the two is omitted and only the different constitution will be explained below. In the coal gasification combined cycle system of 15 the third embodiment shown in Fig. 3, the method of spraying and feeding the water 14d recovered from the exhaust gas 14a at the exit of the dryer 40 to a heat collection portion 51 on the downstream side of the reaction portion of the gasifier 50 at several stages 20 is shown, though the coal gasification combined cycle system of this embodiment shown in Fig. 4 is structured so as to install a cooling tower 52 in a position on the downstream side of the gasifier 50 and on the upstream side of the dust remover 53 and spray and feed 25 the water 14b recovered from the water recovery tower - 41 65 to the cooling tower 52 via the condensed heat exchanger 70 through the water feed system 15. In the coal gasification system provided in the coal gasification combined cycle system of this 5 embodiment, a coal gasification system having the same basic constitution as that of the second embodiment shown in Fig. 2 is used. In the coal gasification combined cycle system of this embodiment, the feed rate of the water 14b fed to 10 the cooling tower 52, similarly to the coal gasification combined cycle system of the third embodiment shown in Fig. 3, in the water gas shift reactor 55 installed on the downstream side of the gasifier 50 and the dust remover 53, so that the 15 steam/carbon monoxide ratio in the syngas 20 is set within the range necessary to obtain the target carbon monoxide conversion ratio, is adjusted. Namely, the system is structured such that a plant information-operation target 87 such as the coal feed 20 rate and oxygen feed rate to the gasifier 50, the performance of the shift reaction catalyst filled in the water gas shift reactor 55, and the target carbon monoxide conversion ratio is inputted into a control unit 86 and the control unit 86 calculates respectively 25 the flow rate and steam/carbon monoxide ratio of the - 42 exit gas of the gasifier 50 and the steam concentration/carbon monoxide ratio which is necessary at the entrance of the water gas shift reactor 55, obtains the necessary feed rate of the water 14b using 5 these calculated values, and so as to be able to feed the feed rate of the water 14b to the cooling tower 52 installed on the downstream side of the gasifier 50 in this embodiment in place of the heat collection portion 51 of the gasifier 50 of the third embodiment, on the 10 basis of an operational signal outputted from the control unit 86, controls the switching of a flow rate adjustment valve 80 installed in the water feed system 15, and adjusts the feed rate of the water 14b fed from the water recovery tower 65 through the water feed 15 system 15 to the heat collection portion 51 of the gasifier 50. In the coal gasification combined cycle system for generating power using coal including much moisture as fuel, the heat loss for drying coal is large, though 20 according to this embodiment, the heat used for coal drying can be collected as sensible heat of the syngas in the gasifier or at the exit of the cooling tower. In the coal gasification combined cycle system of this embodiment, the steam in the syngas, in the shift 25 reactor on the downstream side, reacts with carbon - 43 monoxide and is converted to hydrogen and carbon dioxide, so that even when the gas is lowered in temperature and is cleaned up on the downstream side of the shift reactor, the heat loss due to condensation of 5 the steam is small and a large part of the heat used for coal drying can be given to the power generation by the gas turbine. And, the temperature of the combustion gas at the gas turbine entrance can be set at 1300'C to 1500'C and 10 at a higher temperature than the power generation by the steam turbine using steam at approximately 200'C, the thermal cycle can be driven, so that the efficiency is high and the heat loss can be reduced excessively. Further, when adjusting the hydrogen/carbon 15 monoxide ratio in the syngas in the coal gasification system or in the carbon dioxide collection type coal gasification combined cycle system, to perform the shift reaction for the syngas, though depending on the property of the shift catalyst, a large quantity of 20 industrial water on the same level as the mass of carbon in the coal is necessary, while according to this embodiment, the moisture possessed by the coal can be given to the syngas, so that the industrial water is unnecessary and the running cost can be reduced 25 excessively.

- 44 As mentioned above, according to this embodiment, a coal gasification combined cycle system capable of adjusting the carbon monoxide and hydrogen ratio in the syngas generated by the gasifier due to the shift 5 reaction of the shift reaction unit and improving the plant efficiency can be realized. {Embodiment 51 Next, the coal gasification combined cycle system which is the fifth embodiment of the present invention 10 will be explained by referring to Fig. 5. The coal gasification combined cycle system of this embodiment shown in Fig. 5 is the same in the basic constitution as the coal gasification combined cycle system of the fourth embodiment shown in Fig. 4, so 15 that the explanation of the constitution common to the two is omitted and only the different constitution will be explained below. In the coal gasification system provided in the coal gasification combined cycle system of this 20 embodiment, similarly to the coal gasification system of the fourth embodiment, a coal gasification system having the same basic constitution as that of the second embodiment shown in Fig. 2 is used. In the coal gasification combined cycle system of 25 this embodiment, two water recovery systems for - 45 condensing and recovering the moisture contained in the combustion exhaust gas discharged from the gas turbine 62 are arranged. Among the two water recovery systems arranged to 5 condense and recover the moisture contained by the combustion exhaust gas 14 of the gas turbine, one side of the water recovery system 15a is structured so as to permit the combustion exhaust gas 14 discharged from the gas turbine 62 to be used to dry the coal 1 by the 10 coal dryer 40, then feed it to the water recovery tower 65 via a condensed heat exchanger 70a as combustion exhaust gas 14a, and feed the water 14b recovered from the combustion exhaust gas 14a by the water recovery tower 65 to the cooling tower 52 installed on the 15 downstream side of the gasifier 50 from the water recovery tower 65 through the water feed system 15a. Further, as shown in the coal gasification combined cycle system of the third embodiment shown in Fig. 3, as a feed destination of the water 14b recovered by the 20 water recovery tower 65, the water can be fed to the gasifier heat collection portion 51 on the downstream side of the reaction portion of the gasifier 50. In the coal gasification combined cycle system of this embodiment, among the two water recovery systems 25 arranged to condense and recover the moisture contained - 46 in the combustion exhaust gas 14 of the gas turbine, the other side of the water recovery system 16, as shown in the coal gasification combined cycle system of this embodiment shown in Fig. 5, is structured so as to 5 branch the combustion exhaust gas 14 discharged from the gas turbine 62 from the upstream side of the coal dryer 40 and feed it to a water recovery tower 67 installed separately from the water recovery tower 65 via a condensed heat exchanger 70b, recover the water 10 16b from the combustion exhaust gas 14 by the water recovery tower 67, and feed the water 16b recovered from the water recovery tower 67 to a humidifying tower 64 for humidifying air pressurized by the gas turbine compressor 61 through the water feed system 15b. 15 And, the air humidified by spraying the water 16a by the humidifying tower 64 is fed to the gas turbine combustor 60 and is used to burn fuel by the gas turbine combustor 60 to generate combustion gas, and the combustion gas is fed to the gas turbine 62 to 20 drive the gas turbine 62. As mentioned above, when arranging the water recovery system for recovering the moisture contained in the combustion exhaust gas 14 of the gas turbine as two systems of the water feed system 15a and the water 25 feed system 16b, the combustion exhaust gas 14a at the - 47 exit of the dryer 40 is not fed to the gas turbine 62, so that even when an fault occurs in the dust remove unit 41 installed on the exit side of the dryer 40 and minute particles are mixed in the combustion exhaust 5 gas 14a at the exit of the dryer 40, the minute particles are not fed to the gas turbine 62, so that the risk of damaging the blades of the gas turbine 62 rotating at high speed can be reduced. Further, even if the fault occurs in the dust 10 remove unit 41 and the minute particles are mixed into the combustion exhaust gas 14a discharged from the exit of the dryer 40 and flow into the water recovery tower 65, and even if, in correspondence with the liquid water 14b recovered by the water recovery tower 65, the 15 minute particles are fed into the cooling tower 52 installed on the downstream side of the gasifier 50, and on the downstream side of the cooling tower 52, the dust remover 53 for removing dust from the syngas 16 fed from the gasifier 50 is installed, so that the 20 minute particles can be removed by the dust remover 53, thus the minute particles do not reach the gas turbine 62. The coal gasification combined cycle system of this embodiment is structured so as to, by separating to the 25 combustion exhaust gas 14a (it is highly possible that - 48 minute particles are included) with the coal 1 dried by the dryer 40 and the combustion exhaust gas 14 discharged from the gas turbine 62 branching on the upstream side of the dryer 40, feed them respectively 5 to the water recovery towers 65 and 67 and recover the water 14b and 16b from the combustion exhaust gases 14a and 14, so that even when humidified air is fed to the gas turbine combustor 60 from the water recovery tower 67 via the humidifying tower 64, it can be avoided that 10 the minute particles are mixed into the humidifying tower 64 and are fed to the gas turbine 62 as humidified air, thus the damage risk of the blades of the gas turbine 62 rotating at high speed can be reduced. 15 As mentioned above, according to this embodiment, a coal gasification combined cycle system capable of adjusting the carbon monoxide and hydrogen ratio in the syngas generated by the gasifier due to the shift reaction of the shift reaction unit and improving the 20 plant efficiency can be realized. {Embodiment 6} Next, the coal gasification combined cycle system which is the sixth embodiment of the present invention will be explained by referring to Fig. 6. 25 The coal gasification combined cycle system of this - 49 embodiment shown in Fig. 6 is the same in the basic constitution as the coal gasification combined cycle system of the fifth embodiment shown in Fig. 5, so that the explanation of the constitution common to the two 5 is omitted and only the different constitution will be explained below. In the coal gasification system provided in the coal gasification combined cycle system of this embodiment, similarly to the coal gasification system 10 of the fifth embodiment, a coal gasification system having the same basic constitution as that of the second embodiment shown in Fig. 2 is used. In the coal gasification combined cycle system of this embodiment, as a coal drying method, when a method 15 of continuously drying coal, for example, a method of permitting the coal to make contact with the combustion exhaust gas by transferring the coal from the entrance of the dryer to the exit thereof by a belt conveyer is used, as for the dryer for drying the coal 1, by one 20 dryer, a system can be constructed. As a coal drying method, in a batch type, for example, in a method of fluidizing and drying coal by combustion exhaust gas with the dryer filled with a fixed amount of coal, for example, as shown in Fig. 6, 25 it is desirable to install two or more dryers for - 50 drying the coal 1 such as a dryer 40a and a dryer 40b in parallel. The reason is that if the feed of the water 14b recovered from the combustion exhaust gas 14a of the 5 gas turbine 62 by the water recovery tower 65 to the cooling tower 52 installed on the downstream side of the gasifier 50 is stopped, for the quantity, the feed of the steam 12 fed to the shift reactor 55 from the outside on the entrance side of the shift reactor 55 10 becomes necessary. When as a dryer for drying the coal 1, two dryers of the dryer 40a and the dryer 40b are installed, while the combustion exhaust gas 14 passes through one side of the dryer 40a from the gas turbine 62, the feed of 15 the combustion exhaust gas 14 to the other side of the dryer 40b from the gas turbine 62 is stopped, and the coal 1 in the other side of the dryer 40b is discharged to the coal feed system for feeding coal to the gaisifer 50. 20 When the coal discharge is finished, the other side of the dryer 40b is filled with the non-dried coal 1. And, at the stage when the drying of the coal 1 by one side of the dryer 40a is completed, the feed of the combustion exhaust gas 14 which is fed from the gas 25 turbine 62 to the one side of the dryer 40a is stopped - 51 and is switched to the feed of the combustion exhaust gas 14 to the other side of the dryer 40b from the gas turbine 62. And, after the feed destination of the combustion 5 exhaust gas 14 discharged from the gas turbine 62 is switched from one side of the dryer 40a to the other side of the dryer 40b, the dried coal 1 in one side of the dryer 40a is discharged to the coal feed system for feeding coal to the gasfier 50. 10 In the coal gasification combined cycle system of this embodiment, coal containing much moisture classified to brown coal and peat is gasified, and syngas having main components of carbon monoxide and hydrogen is produced, and it can be applied to the coal 15 gasification system for synthesizing chemical products such as methanol from the syngas and the coal gasification combined cycle system for generating power using the syngas as fuel by the gas turbine. As mentioned above, according to this embodiment, a 20 coal gasification combined cycle system capable of adjusting the carbon monoxide and hydrogen ratio in the syngas generated by the gasifier due to the shift reaction of the shift reaction unit and improving the plant efficiency can be realized. 25 Throughout this specification and the claims which - 52 follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps 5 but not the exclusion of any other integer or step or group of integers or steps. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as 10 an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavor to which this specification relates.