CA2184531C

CA2184531C - Method for producing hydrogen-carbon monoxide mixed gas, and apparatus thereof

Info

Publication number: CA2184531C
Application number: CA 2184531
Authority: CA
Inventors: Fumihiko Kiso; Norio Arashi; Atsushi Morihara; Shuntaro Koyama
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1995-08-31
Filing date: 1996-08-30
Publication date: 1999-10-12
Anticipated expiration: 2016-08-30
Also published as: AU6206496A; DE19634857C2; JPH0967582A; CN1152021A; AU694052B2; DE19634857A1; CA2184531A1; CN1066186C

Abstract

A method and apparatus for producing methyl alcohol with high efficiency and low cost involve producing an H2-CO mixture that is used for synthesizing methyl alcohol, using coal, natural gas, steam, and an oxidizing agent, such as oxygen, as raw materials. At least one of the ratios of natural gas/coal, oxygen/coal, and steam/natural gas are controlled to generate the H2-CO mixture in which the ratio of H2/CO is equal to 2, which is suitable for synthesizing the methyl alcohol.
In producing the H2-CO mixture, coal and oxygen are reacted to generate CO, CO2, H2O, H2, and heat, and the heat is utilized to react the natural gas and steam for generating the H2-CO
mixture. In comparison with conventional methods for producing methyl alcohol from natural gas, and by coal gasification, the conversion ratio from the raw material to methyl alcohol can be improved by about 10 - 15 %.

Description

A METHOD FOR PRODUCING HYDROGEN-CARBON
MONOXIDE MIXED GAS, AND APPARATUS THEREOF

The present invention relates to a method for producing hydrogen (H2)-carbon monoxide (CO) mixed gas, which is used as a raw material for synthesizing organic compounds, such as methyl alcohol and/or as fuel for power generation, from coal, and/or natural gas, and a method for producing methyl alcohol using the hydrogen-carbon monoxide mixture produced by a method of the present invention.
A method for producing methyl alcohol using natural gas as a raw material, and a method using coal as a raw material are well known to the public.
Regarding using natural gas (main component: CH4), the method can be roughly divided into two kinds: one uses a catalyst and the other uses no catalyst. The method using a catalyst, such as the one disclosed in JP-A-51-29408 (1976), is mainly used. In accordance with a method using natural gas, the natural gas is first treated in desulfurizing equipment for removing hydrogen sulfide (H2S) contained in the natural gas. Subsequently, the desulfurized natural gas and steam are introduced into a natural gas reforming equipment for obtaining H2-CO mixture by a reaction of natural gas and steam indicated by the following equation (1):

CH4 + H2O ~ 3H2 + CO ... (1) When a catalyst is used, a nickel-based catalyst comprising a carrier, such as heat resistant alumina, is used, and a temperature of 800 ~ 900C is necessary for the reaction condition. The reaction expressed by equation (1) is an endothermic reaction, and heat must be supplied continuously in order to maintain the necessary temperature for the reaction, i.e. 800 ~ 900C. Generally, the heat of combustion of natural gas, which is expressed by the following equation (2), is utilized as a heat source.

CH4 + 2O2 ~ 2H2O + CO2 ... (2) In the case when a catalyst is not used, a high temperature in the range of 1000 ~ 1600C is necessary to produce the reaction expressed by equation (1), and the high temperature can be obtained by the reaction expressed by equation (2) in the reactor vessel. In this case, the reaction expressed by equation (3) also proceeds in the equipment.

CH4 + CO2 ~ 2H2 + 2CO ... (3) The generated H2-CO mixture is introduced into methyl alcohol synthetic equipment for synthesizing methyl alcohol by the reaction expressed by equation (4).

2H2 + CO ~ CH30H ... (4) The composition of the H2-CO mixture obtained from natural gas by the reaction of equation (1) is stoichiometrically [H2]/[CO] = 3, while the composition of the H2-CO mixture suitable for synthesizing methyl alcohol by the reaction of equation (4) is [H2]/[CO] = 2. Therefore, the composition of the H2-CO mixture must be adjusted in order for the reaction to proceed effectively. Generally, a shift reaction expressed by an equilibrium equation (5) is used for converting H2 to CO.

CO + H20 ~ CO2 + H2 Because the reaction proceeds to convert the composition of the H2-CO mixture obtained from the natural gas from [H2]/[CO] = 3 to [H2]/[CO] = 2, a part of the H2 must be converted to CO by adding CO2. One of the general methods for obtaining CO2 on a commercial scale is pyrolysis of lime stone (CaCO3). However, the pyrolysis of lime stone is not effective only for the production of CO2. It is economical only when, 2~84~311 -for instance, calcium hydroxide (Ca (OH) 2) iS produced concurrently.
Accordingly, the shift reaction, wherein CO2 is added, is seldom utilized in a methyl alcohol production plant, except when a CO2 production plant is located nearby. Generally, the excess hydrogen at the methyl alcohol synthesis is separated with other residual gases from methyl alcohol, and utilized as fuel for steam heating equipment. That means, the energy of the excess hydrogen is converted to thermal energy, and transferred to the energy of steam via a heat exchanger.
Accordingly, a large loss of energy cannot be avoided.
For the reason explained above, the converting efficiency, which is the rate of energy converted to methyl alcohol from the natural gas, by the method of producing methyl alcohol from natural gas, is approximately 70~, and significant improvement in the converting efficiency cannot be expected theoretically.
In accordance with a method using coal as a raw material, coal and an oxidizing agent are introduced into a gasifier for gasification, as disclosed in U.S. Patent 4,773,917. The gas generated by the gasification of coal also can be used for electric power generation, as disclosed in JP-A-59-196391 (1984). Coal itself is an organic compound composed of oxygen, sulfur, nitrogen, and ashes, in addition to carbon and hydrogen. However, if it is simplified as CH, the gasification reaction of coal is essentially expressed by equation (6).

2CH + 2 ~ 2CO + H2 ... (6) In order to gasify the coal, the gasification reactor must be maintained at a temperature in the range of 900 ~ 1600C, but no heat source is necessary, because the reaction expressed by equation (6) is exothermic. However, if the exhaust heat is not utilized, the energy utilization efficiency cannot be improved. The gas exhausted from the coal gasification reactor contains fly ash and H2S. The fly -ash is recovered by dust removal equipment, and the H2S is removed by desulfurization equipment. The composition of H2-CO
mixture gas obtained from coal by the reaction of equation (6) is stoichiometrically [H2]/[CO] = 0.5. The composition suitable for synthesizing methyl alcohol from H2-CO mixed gas is [H2]/[CO] = 2, as expressed by equation (4), and the value is larger than the ratio of [H2]/[CO] in the H2-CO mixture obtained by the coal gasification. Therefore, the composition of the H2-CO mixture obtained by the coal gasification must be converted in order to produce methyl alcohol. The shift reaction expressed by equation (5) is used for this conversion. In this case, a part of the CO is converted to H2 by adding H2O. A temperature drop in the system cannot be avoided with the addition of H2O, and consequently the addition of water is a disadvantage for effective utilization of exhaust heat at the coal gasification. The exhaust heat at the coal gasification can be recovered as electric power, but it is impossible to recover it as methyl alcohol.
Theoretically, the exhaust heat at the coal gasification cannot be reduced to less than about 20~ of the energy of the coal, nor can the exhaust heat when producing methyl alcohol from the H2-CO mixture be reduced to less than about 15~ of the energy of the H2-CO mixture. For the above reason, the ratio of the energy converted to methyl alcohol to the total energy of the coal, that is, the conversion ratio is approximately 65~, and a significant improvement to more than 65~ cannot be expected theoretically.
In accordance with the conventional method of producing methyl alcohol using natural gas or coal as the raw material, a significant increase in the efficiency has been theoretically impossible, even if the most extensive improvement was obtained for increasing the conversion ratio to methyl alcohol from the raw material. One of the reasons is that the composition of the H2-CO mixture suitable for the production of methyl alcohol must have the ratio of [H2]/[CO] = 2, while the H2-CO mixture obtained from natural gas has the ratio of [H2]/[CO] = 3, and the H2-CO mixture - 21~45~ - 5 -obtained from coal has the ratio of [H2]/[CO] = 0.5. Another reason is that the exhaust heat cannot be reduced theoretically to less than 20~ when coal is used as the raw material, nor can the exhaust heat be recovered as methyl alcohol.
One of the objects of the present invention is to provide a method to produce an H2-CO mixture having an arbitrary ratio of [H2]/[CO] in the range of 0.5 ~ 3.
Another object of the present invention is to provide a novel method for producing methyl alcohol using the above method to produce the H2-CO mixture, which can overcome the above-mentioned limit of the prior art, and provide a method for producing methyl alcohol realizing a significantly higher efficiency and lower cost than the prior art.
Further, another object of the present invention is to provide an integrated energy system that is capable of using the above novel method for producing methyl alcohol, and of responding to variations of power demand in maintaining the load on the H2-CO mixture production plant stable in concurrent production of methyl alcohol and electric power.
In accordance with the present invention, an H2-CO mixture having a suitable composition for producing methyl alcohol can be produced by using both hydrogen-rich natural gas and carbon-rich coal as raw materials, and controlling the supply ratio of the natural gas and the coal. The heat efficiency can be improved and the need for a heat exchanger can be avoided by reacting the coal with oxygen, and the natural gas with steam in the same reactor.
The theoretical background for determining the operating conditions of the preferred system is explained in detail hereinafter.
When coal, natural gas, oxygen, and steam are fed into a reactor simultaneously, a reaction with the coal does not proceed, because the natural gas, oxygen, and steam are in a gaseous condition, while only the coal is solid. Comparing the reactivity of oxygen and steam with natural gas, the reactivity of the oxygen with the natural gas is larger than that of steam. Accordingly, a combustion reaction expressed by equation (8), wherein the natural gas is combined with oxygen, proceeds prior to the steam reforming the reaction expressed by equation (7), wherein the natural gas reacts with steam to generate carbon monoxide.

CH4 + H2O ~ 3H2 + CO ... (7) CH4 + 2O2 ~ 2H2O + CO2 ... (8) When the reaction of equation (8) occurs, the generated H2O and CO2 must be reduced to H2 and CO. Therefore, the reactions of equations (9) and (10), that is, reactions of H2O
and CO2 with char (carbon component, coal without volatiles can be used.

C + H20 ~ H2 + CO . . . ( 9 ) C + CO2 ~ 2CO ... (10) However, the char is utilized and consumed for reducing the CO2, which is usually contained in volatile coal, and the H2O and CO2 are generated by the oxidation of H2 and CO, which are contained in the volatile coal. Therefore, the char cannot be utilized for reducing H2O and CO2 generated by the reaction of equation (8).
For this reason when coal and natural gas react in the same reactor a suitable designing of the reactor and an adequate setting of the operating condition become necessary, so that the natural gas does not cause the combustion reaction of equation (8), but only the steam reforming reaction of equation (7) proceeds.
First, the reaction with coal is now explained. An example of coal composition, for instance pacific ocean coal, is indicated in Table 1.

21 ~4531 -Composition of Coal (Pacific Ocean Coal) Industrial analysis Wt.
Moisture 2.8 Ashes 14.4 Volatiles 45.2 Fixed Carbon 37.6 Element analysis daf Carbon 77.82 Hydrogen 6.73 Nitrogen 1.09 Sulfur 0-05 Oxygen 14.32 The reaction of coal with oxygen can be expressed by a model shown in FIG. 4. In order to indicate the reaction conditions and others in detail, a molecular formula of coal is expressed as CaHbOCNdSe, and coal is taken as being composed of moisture, volatiles, fixed carbon, and ashes in accordance with the above industrial analysis. The moisture is evaporated by heating the coal, and the volatiles and char, of which the main component is carbon, are separated by pyrolysis. The industrial analysis is performed at atmospheric pressure, but the reaction proceeds under a pressurized condition. Therefore, the amount of volatile, V
[~ by weight: wt. ~], generated by the pyrolysis of coal can be calculated from the value under one atmosphere, V 1 atm [wt. ~], obtained by the industrial analysis by the following mathematical equation (1):
V = V 1 atm (1-0.066-ln Pt) (Math. 1) where, Pt: Pressure in the reactor [atm]
The pressure in the reactor is preferably set at 30 [atm]. The volatiles react with oxygen to generate CO2 and 21 84~311 H2O. This reaction can be expressed by the following equation (11):
CaHbcNdSe + ~ 2 ~ fC(Char) + (b - 2e)/2 H2O + e H2S + d/2 N2 + (2 (a-f) - c - 2 ~ + (b - 2e)/2) CO
+ (c + 2~ - (b - 2e)/2 - (a - f)) CO2 ... (11) Steam reforming of natural gas is preferably concurrently performed in the same reactor by supplying natural gas and steam. However, the reforming reaction is an endothermic reaction, and in the case when a large amount of natural gas is supplied, the heat generated only by the reaction of equation (11) becomes insufficient. In this case, the supply amount of oxygen is increased to burn a part of carbon monoxide as shown by equation (12) to supply additional heat:

2CO + 2 ~ 2C2 ..................................... (12) The above reactions can be assumed to proceed instantaneously. The residual char is solid, and the char is gasified by the reaction with H2O and CO2 which are generated by the combustion of the volatiles, as indicated by the following equations (13) and (14):

C (Char) + H2O ~ H2 + CO ... (13) C (Char) + CO2 ~ 2CO ... (14) However, these reactions cannot be assumed to proceed instantaneously, and a part of the char will remain ungasified if a sufficient residence time is not available. Therefore, in designing the reactor, the relationship between the carbon conversion ratio of carbon in the char and the reaction time must be considered. The relationship between the carbon conversion ratio, Xchar [-] of carbon in the char and the reaction time, ~ [s], can be expressed by a model shown by the following mathematical equations (2), (3), and (4):

2 1 ~453~
-g P CharDP 1 -- ( 1 -- Xchar ) + XChar S PCO + PH o kreact 3kGas ...(Math. 2) kreaCt = 247exp(- T ) 100 ... (Math. 3) k = 8 725 x 10-5 .
Gas P~DP 2000 ... (Math. 4) Where PCO2 : Partial pressure of CO2 pH2O : Partial pressure of H2O
Pchar: Density of char Dp : Particle size of the char kreaCt: Reaction rate constants of the reactions (13) and (14) kGaS: Diffusion coefficient In accordance with the relationship expressed by the above equations, when oxygen and coal are loaded at a mass ratio of oxygen/coal of at least 0.8, the residence time of the coal and the oxygen in the reactor needs to be a few seconds in order to obtain a gasification ratio of the coal of at least 0.9. The relationship between the gas generated by the gasification of coal under the above condition and the mass ratio of oxygen/coal loaded into the reactor is indicated in FIG. 5.
As explained above, natural gas and steam are loaded into the reactor under a condition wherein the reactions of equations (11), (12), (13), (14) have sufficiently proceeded.
Therefore, the combustion of natural gas expressed by equation (15) does not occur.

21845~

.

CH4 + 2O2 ~ 2H2O + CO2 ... (15) Accordingly, an equilibrium of the steam reforming reaction of natural gas expressed by equation (16) and the shift reaction expressed by equation (17) must be considered at the top of the reactor.

CH4 + H2O ~ 3H2 +CO ... (16) CO + H2O ~ H2 + CO ... (17) If the partial pressures of the respective gases at the top of the reactor are expressed as hydrogen p [atm], carbon dioxide q [atm], steam r [atm], carbon monoxide s [atm], and methane t [atm], and the equilibrium constant of the steam reforming reaction of methane of equation (16) is expressed as K1, and the equilibrium constant of the shift reaction of equation (17) is expressed as K2, the equilibriums can be expressed by the following mathematical equations (5) and (6).
p x s = K1 t x r ... (Math. 5) r x s = K2 p x q ... (Math. 6) Where, the equilibrium constants at various temperature are shown in Table 2. The values shown in Table 2 were calculated by the following mathematical equations (8) ~ (11), because thermodynamic theory indicates that the equilibrium constant of a chemical reaction expressed by the mathematical equation (7) can be calculated by the mathematical equations (8) ~ (11).

~Vi Ai =
... (Math. 7) where, Ai : Chemical formula of component I

vi : A stoichiometric coefficient of the component I [-] (It is defined as positive for the raw group and negative for the product group).

Equilibrium constant Temperature (K) Kl K2 800 3.07E-02 2.43E-Ol 900 1.27E+00 4.47E-Ol 1000 2.55E+01 7.17E-Ol 10 1100 3.01E+02 1.05E+OO
1200 2.36E+03 1.42E+OO
1300 1.36E+04 1.82E+OO
1400 6.08E+04 2.24E+OO
1500 2.23E+05 2.67E+OO
15 1600 6.94E+05 3.lOE+OO
1700 1.89E+06 3.52E+OO
1800 4.60E+06 3.93E+OO

InK298 = -RT ~ Gfi ... (Math. 8) (K298) R(To T) (~Vi/~Hfi + ~Lvi - ~I)i Ii(T )) + 1 ~ ~i-(Ji(T) - Ji(To)) ... (Math. 9) Ii~T) = ai-T + 2i T2 + 3i T3 + 4i T4 ... (Math. 10) Ji(T) = ai-InT + 2i T + 6i T2 + 12 T3 ... (Math. 11) Where, K298 Equilibrium constant [-] at 298.15 [K]
KT Equilibrium constant [-] at a temperature T [K]
To The standard temperature (= 298.15 [K]) T: Temperature [K]
~Gfi: Standard Gibbs energy of formation of a component i [J/mol]
~Hfi: Standard heat of formation of a component i [J/mol]
LVi: Heat of vaporization of a component i at To [K]
ai, bi, ci, di: A coefficient of heat capacity at a constant pressure of a component i [J/(mol)-Kn)]

The relationship between the oxygen/coal ratio and the gas concentration at the outlet of the reactor, which is calculated based on the above equations, is shown in FIG. 6.
In the above calculation, the ratio [mass of natural gas]/[mass of coal] was taken as 1, and the ratio [mass of steam]/[mass of natural gas] was taken as 2.
In the above case, the conditions for reacting coal, natural gas, oxygen, and steam in a reactor to generate an H2-CO mixture having a ratio [H2]/[CO] equal to 2, and synthesizing methyl alcohol, are shown in FIG. 7. The loaded mass ratio of oxygen/coal is taken as 1.2. In accordance with the above reactions, a reacted gas having a composition of [H2] = 20%, [H2O] = 15%, [CO] = 43%, [CO2] = 21%, at 1500C can be obtained. By adding natural gas 1 and steam to the reacted gas, a reacted gas having a composition of [H2] = 48%, [H2O] = 19%, [CO] = 24%, [CO2] = 6%, at 1000C can be obtained.
This composition of the gas is suitable for synthesizing methyl alcohol.
In order to recover the exhaust heat downstream from the reactor, the mass of steam loaded into the reactor is 2~ 84~3~

preferably small. When making the ratio of [mass of steam]/[mass of natural gas] = 1.5, a mixture having a composition of [H2]/[CO] = 2 can be obtained by making the ratio [mass of natural gas]/[mass of coal] = 1.3, and the ratio [mass of oxygen]/[mass of coal] = 1.6.
A mixture having a composition of [H2]/[CO] equal to a value other than 2 can be obtained by selecting the values of the ratio [mass of natural gas]/[mass of coal] and the ratio [mass of oxygen]/[mass of coal] from a region shown in FIG. 8, and adjusting the amount of steam.
Power generating equipment can be installed in parallel with the methyl alcohol producing equipment at the downstream region of the H2-CO mixture producing equipment. With the above system, the rate of operation of the equipment producing the H2-CO mixture of gases was kept to a constant rate, and the supply proportion of the H2-CO mixture fed to the methyl alcohol producing equipment and the power generating equipment was varied corresponding to the variations in power demand.
Depending on the availability factor of the system, that is, the rates of operation of the power generating equipment and the methyl alcohol producing equipment, the most economical amounts of supplying coal, natural gas, oxygen, and steam were calculated, and the supply amounts of the raw material were controlled to be the same as the calculated values.
Practically, the adjustment was performed as follows:
When only methyl alcohol production is performed, the supply amounts of the raw materials are controlled to obtain a mixed gas having the ratio [H2]/[CO] = 2, and methyl alcohol is produced. When both methyl alcohol production and power generation are performed concurrently, unreacted gas generated at the methyl alcohol synthesizing equipment is not returned to the methyl alcohol synthesizing equipment, but is supplied to the power generating equipment as fuel for power generation. When only power generation is performed, the supply of natural gas is stopped, and power is generated using gas generated from the coal and oxidizing agents.

2184~31 -The composition of the H2-CO mixture for synthesizing methyl alcohol can be controlled without performing the shift reaction, and accordingly an effective utilization of energy can be realized. In a case where the coal and the natural gas are treated in the same reactor, a heat exchanger to supply heat for reforming the natural gas becomes unnecessary, and simultaneously a decrease in the cost for producing methyl alcohol can be realized by decreasing the number of members keeping a high energy utilization factor. The efficiency of producing methyl alcohol can be increased by 10 ~ 15~ in absolute value from the theoretical limit of conventional methyl alcohol production by producing methyl alcohol from a mixed gas having the ratio [H2]/[CO] = 2 generated by a method of the present invention.
Furthermore, in a system wherein power generating equipment is installed in parallel with the methyl alcohol producing equipment, the load for coal gasification can be kept stable, corresponding to the variations in power demand.
Depending on the availability factor of the system, that is, the rates of operation of the power generating equipment and the methyl alcohol producing equipment, the most economical amounts of supply coal, natural gas, oxygen, and steam can be calculated, and the supply amounts of the raw material are controlled to be the same as the calculated values.
A high efficiency methyl alcohol producing system using coal and natural gas according to the present invention can realize a significant energy saving when the energy is transported by sea for a long distance.
That means, in comparison with the transportation of solid coal, and the transportation of the natural gas that is required to liquefy the gas, when the above materials are converted to methyl alcohol, the handling becomes easy, and mass transportation by tankers that are used in the conventional transportation of oil, becomes possible.

In the drawing:
FIG. 1 is a schematic illustration of an integrated energy system comprising H2-CO mixture producing equipment using natural gas and coal as raw materials in accordance with an embodiment of the present invention, methyl alcohol producing equipment, and power generating equipment;
FIG. 2 is a schematic cross section of an embodiment of a reactor for realizing the H2-CO mixture using natural gas and coal as raw materials;
FIG. 3 is a schematic cross section of another embodiment of a reactor for realizing the H2-CO mixture using natural gas and coal as raw materials;
FIG. 4 is an illustration for explaining a mechanism of gasification of coal;
FIG. 5 is a graph indicating the relationship between the ratio of oxygen/coal loaded into the H2-CO mixture producing equipment and the gas composition at a lower level of the reactor;
FIG. 6 is a graph indicating the relationship between the ratio of oxygen/coal loaded into the H2-CO mixture producing equipment and the gas composition at an upper level of the reactor;
FIG. 7 is an illustration indicating optimum operating conditions of the methyl alcohol producing equipment;
FIG. 8 is a graph indicating the relationship between the composition of loaded raw material and the composition of H2-CO
mixture;
FIG. 9 is a graph for explaining a method for effectively operating the integrated energy system that comprises methyl alcohol producing equipment using natural gas and coal as raw materials, and power generating equipment;
FIG. 10 is a schematic illustration of a methyl alcohol producing equipment using a H2-CO mixture, using natural gas and coal as raw materials; and FIG. 11 is a schematic cross section of another embodiment of the present invention.

21 8453 !

(Embodiment 1) FIG. 1 indicates an integrated energy system in accordance with an embodiment of the present invention. The system comprises a raw material supply division 100, a H2-CO
mixture producing division 200, a gas distributing division 500, a methyl alcohol producing division 300, and a power generation division 400. The raw material supply division 100 supplies coal 10, natural gas 20, oxygen 11, and steam 22 to the H2-CO mixture producing division 200. The H2-CO mixture is distributed to the methyl alcohol producing division 300 and the power generating division 400 by the gas distributing division 500 in order to supply both methyl alcohol and electric power.
The structures of the above divisions are now explained in detail.
The raw material supply division 100 comprises a coal supply section, an oxygen supply section, a natural gas supply section, and a steam supply section.
The coal supply section comprises a hopper 110 and a coal supply control valve 111. The hopper 110 is an apparatus to store coal pulverized to under-100 mesh 90~, from which coarse cohesive materials are eliminated, and to pressurize the atmosphere inside the hopper with nitrogen 12 which is a by-product from an oxygen producing apparatus 130. The coal supply control valve 111 controls the amount of the raw coal supplied, depending on the operating condition of the system.
The oxygen supply section comprises an oxygen producing apparatus 130 and an oxygen supply control valve 131. The apparatus 130 is an apparatus to pressurize and liquefy air by a compressor, and to distill the liquefied air for separating oxygen and nitrogen, the main component of air. The oxygen supply control valve 131 controls the amount of the oxygen, an oxidizing agent, depending on the operating condition of the system.
The natural gas supply section comprises a natural gas storage tank 120 and a natural gas supply control valve 121.
The natural gas is supplied directly through a pipe line.

2184~3~

However, the natural gas storage tank is a facility to store extra natural gas for ensuring stable operation of the methyl alcohol producing apparatus with a predetermined load, if the supply of the natural gas through the pipe line becomes unstable. The natural gas supply control valve 121 is a valve to control the supplied amount of the natural gas depending on the operating condition of the system.
The steam supply section comprises a cooling water storage tank 140 and a steam supply control valve 141. The liquid cooling water 21 stored in the cooling water storage tank 140 is heated by being supplied to a heat recovery portion 213 of a reactor 210 to generate steam 22 at a high temperature. A part of the steam 22 is supplied to the reactor 210 through the steam supply control valve 141, which is a valve to control the supplied amount of the steam depending on the operating condition of the system.
The H2-CO mixture producing division 200 comprises the reactor 210, a dust removal apparatus 240, and a desulfurizing apparatus 2 50.
The reactor 210 comprises a lower stage burner 211 for supplying the coal 10 and the oxygen 11, an upper stage burner 212 for supplying the natural gas 20 and the steam 22, the heat recovery portion 213 for cooling the reacted gas, and a slag cooling tank 221 for collecting slag generated by fusing the ash components of the coal.
The dust removal apparatus 240 iS an apparatus for collecting solid dust in the reacted gas, and in practice a cyclone, or a ceramic filter, can be used.
The desulfurizing apparatus is for removing H2S gas in the reacted gas, and, for instance, the so-called selexol process can be utilized. In accordance with the selexol process, H2S
gas is absorbed once into an organic solvent, the absorbed H2S
is extracted from the solution when the concentration of the H2S in the solution becomes high. The extracted H2S gas having a high concentration is oxidized to SO2, and the SO2 is removed by fixing as gypsum by reacting with a slurry of calcium carbonate, which is a conventional method used in coal fired 21~4~3 power plants. A dry desulfurizaton method can also be used, wherein H2S gas is directly fixed with fine particles of calcium carbonate, zinc oxide, or the like.
The methyl alcohol producing division 300 comprises a 5 methyl alcohol synthesizing apparatus 310, a methyl alcohol distillation section, and heat exchangers. The methyl alcohol synthesizing apparatus 310 is for synthesizing methyl alcohol from the H2-CO mixture, and a catalyst, such as a ZnO group catalyst, can be utilized. The reaction condition is about 300C at 100 atmosphere. The reaction generating methyl alcohol is an exothermic reaction, and the reaction heat is recovered and utilized in a rear stage in order to increase the heat efficiency of the whole system. In order to recover the reaction heat, heat exchangers 340, 350, 360, are used.
The methyl alcohol distillation section is for obtaining purified methyl alcohol by removing impurities from crude methyl alcohol, which comprises a first distillation column 320 and a second distillation column 330. The exhaust heat of the methyl alcohol synthesizing process recovered by the heat exchanger 350 can be utilized as the energy necessary for the distillation.
The power generation division 400 comprises a gas turbine 410, a heat recovery steam generator 420, and a steam turbine 430, which is used for combined cycle power generation.
The gas turbine 410 burns the H2-CO mixture with air 60 pressurized by a compressor, the turbine being driven by the combustion gas to generate electric power. The heat recovery steam generator 420 recovers heat energy from the combustion exhaust gas 65 of the gas turbine 410 in the form of steam 67.
The steam turbine 430 is driven by the steam 67 to generate electric power.
The operating conditions of the system in the present embodiment are now explained.
The operation conditions must be determined so that the coal and natural gas can react in a same reactor. If coal, natural gas, oxygen, and steam are mixed together and supplied into the reactor at the same time, the reaction of coal cannot 21~4~3~

proceed, because the natural gas, oxygen, and steam are gases, but coal is solid. Compared to the reactivity of natural gas and water with that of natural gas and oxygen, the reactivity of natural gas and oxygen is high. That means, the combustion reaction expressed by equation (19), wherein natural gas combines with oxygen, proceeds first before the steam reforming reaction expressed by equation (18), wherein the natural gas combines with steam to generate carbon monoxide, occurs.

CH4 + H2O ~ 3H2 + CO ................................ (18) CH~ + 2O2 ~ 2H2O + CO2 ... (19) Therefore, when making coal and natural gas react in the same reactor, the operating condition must be controlled so that the natural gas does not cause the combustion reaction expressed by equation (19), but proceeds with the steam reforming reaction expressed by equation (18).
In accordance with the present embodiment of the invention, the coal and the oxygen are fed into a lower portion of the reactor, while the natural gas and the steam are supplied to an upper portion of the reactor. The shapes of the reactor portions, the methods for supplying raw materials, and the ratio of supplied coal and oxygen are controlled so that the coal and the oxygen supplied from the lower portion into the reactor react sufficiently. If it is expressed by the ratio of gaseous carbon to total carbon in the coal, the ratio is at least 0.9, before contacting the natural gas, and the steam is supplied from the upper portion into the reactor. Practical compositions and functions of the reactor are explained in detail in embodiments 2 and 3.
In order to form whirl flows of coal and natural gas in the reactor, upper burners and lower burners are arranged oriented in a direction tangential to the inner wall of the reactor. In accordance with the method explained above, an H2-CO mixture having a ratio, [H2]/[CO], of 2 was produced, and methyl alcohol was prepared from the H2-CO mixture.

2~84~33 When methyl alcohol is prepared from the raw materials of coal (Pacific ocean coal) 100 ton/day, oxygen 120 ton/day, natural gas 100 ton/day, and steam 200 ton/day, 260 ton/day of methyl alcohol can be prepared, and the conversion ratio of energy of the raw materials to the methyl alcohol becomes about 80~. In comparison with the conventional method for producing methyl alcohol, a significant increase in the conversion ratio, such as 10 ~ 15~ in absolute value becomes possible with this system.
An example of operation of the system is now explained.
Pulverized coal 10 is supplied from a hopper 110 into the reactor 210 of the H2-CO mixture producing division 200 through the coal supply control valve 111 and the lower stage burner 211. Oxygen 11 is produced in the oxygen producing apparatus 130 and is supplied to the reactor 210 of the division 200 through the oxygen supply control valve 131 and the lower stage burner 211.
Pressurized nitrogen 12, which is also obtained at the oxygen producing apparatus 130 by distillation of liquefied air, is used for pressurizing the pulverized coal 10. Both the natural gas 20 stored in the natural gas storage tank 120 of the division 100, and the steam 22 heated by heat recovered from the reactor 210 by the heat recovery portion 213, are supplied to the reactor 210 of the division 200 through the natural gas supply control valve 121 or the steam supply control valve 141. The reactor 210 shown in FIG. 2 is provided with the lower stage burner 211 and the upper stage burner 212 at places separated by a long distance, so that a certain retention time can be ensured before contacting the reacted gas of the coal and the oxygen with the natural gas and the steam. Another reactor shown in FIG. 3, which has a constriction at a middle portion of the reactor 210, can also be useful.
Slag, which is fused from coal in the reactor, can be recovered at a slag cooling tank 221. Exhaust heat from the reactor is recovered by the heat recovery portion 213 as the steam 22. The reacted gas 30 from the reactor 210 is treated 2 1 8 ~

by a dust removal apparatus 240 for removing dust, and a desulfurizing apparatus 250 for removing H2S.
The cleaned H2-CO mixture 40 is distributed by a gas distributor 500 to the methyl alcohol producing division 300 5 and the power generating division 400.
At the methyl alcohol producing division 300, crude methyl alcohol 50 is synthesized from the H2-CO mixture 40 by the methyl alcohol synthesizing apparatus 310. The crude methyl alcohol is purified by distillation at the first distillation column 320 and the second distillation column 330 to become purified methyl alcohol 51. At the methyl alcohol producing division 300, unreacted gas 52 separated from the crude methyl alcohol at the first distillation column 320 is heated in the heat exchanger 340, and returned to the methyl alcohol synthesizing apparatus 310. When electric power is generated concurrently, the unreacted gas is supplied to the power generation division 400. Exhaust heat at the methyl alcohol synthesis is recovered by the heat exchanger 350, and is utilized at the second distillation column 330 using the heat exchanger 360.
At the power generation division 400, the H2-CO mixture 40 is burnt with compressed air 60 to drive the gas turbine 410 and generate electric power. Exhaust gas of the gas turbine 410 is recovered by the heat recovery generator 420 as steam 67, and the steam 67 is used for driving the turbine 430.
A method for supplying raw materials to the system is now explained.
When only methyl alcohol is produced, the H2-CO mixture gas 40, having a ratio [H2]/[CO] of 2 suitable for producing methyl alcohol, is produced at the division 200 using coal 10, an oxidizing agent such as oxygen 11, natural gas 20, and steam 22. All of the H2-CO mixture is supplied to the methyl alcohol producing division 300 through the apparatus 500, and crude methyl alcohol 51 is produced. When only electric power is generated, the natural gas is not supplied to the reactor, and the H2-CO mixture 40 is produced at division 200 using coal 10, which is cheaper than natural gas, an oxidizing 21~4`5~.1 agent, such as oxygen 11, and steam 22. The generated H2-CO
mixture is supplied to the power generation division 400 through the distribution apparatus 500, and power is generated. In this case, the amount of coal supplied can be increased by making the upper stage burner changeable from a natural gas supply to a coal supply, and vice versa. When both methyl alcohol and electric power are produced, the ratio of the natural gas 20 supply to the coal 10 supply is decreased to be smaller than the case when only methyl alcohol is produced, in order to decrease the cost of the power generation. In this case, the composition of the H2-CO mixture 40 has a ratio [H2]/[CO] smaller than 2, and unreacted CO gas 52 is generated in the methyl alcohol synthesis. The unreacted CO gas 52 is separated from the methyl alcohol at the first distillation column 320, and is supplied to the power generation division 400 after being heated by the heat exchanger 340 to be utilized for power generation. Therefore, the energy utilization efficiency of the whole system does not decrease. The above relationship is summarized in FIG. 9 as a graph indicating the relationship of the operating ratio of the methyl alcohol producing apparatus and the electric power generation apparatus to the supplied amounts of raw materials (natural gas/coal, oxygen/coal).
(Embodiment 2) An embodiment of the reactor 210 of the H2-CO mixture gas producing apparatus, using natural gas and coal as raw materials, is indicated in FIG. 2. The whole reactor 210 is composed of refractory material 216 surrounded by a vessel 217, and the reactor is divided into three zones, an upper zone 218, an intermediate zone 219, and a lower zone 215.
Upper stage burners 212 are installed in the upper zone, and lower stage burners 211 are installed in the lower zone. A
slag trap 220 is provided at the lower zone, and a slag cooling tank 221 is located beneath the slag trap. A
constriction 222 is located at the outlet portion of the intermediate zone. The upper stage burners 212 and the lower stage burners 211 are directed in a tangential direction to ~l8~

the inner wall of the reactor so as to form whirl flows as indicated in FIG. 2. Generally, a plurality of the upper stage burners and the lower stage burners are provided circumferentially around the reactor. In FIG. 2, although the upper stage and the lower stage burners are each shown as only a single row, they can be arranged in plural rows.
The coal and the oxidizing agent supplied into the intermediate portion of the reactor from the lower stage burners form a whirl flow, their reaction being enhanced by the whirl flow. Similarly, the natural gas and the steam supplied into the reactor from the upper stage burners form a whirl flow, their reaction also being enhanced by the whirl flow.
The function of the present embodiment is now explained.
The coal 10 and the oxidizing agent such as oxygen 11 are supplied to the reactor from the lower stage burner 211, and the natural gas 20 and the steam 22 are supplied to the reactor from the upper stage burner 212. Reacted gas ascends from the intermediate zone 219 of the reactor to the upper zone 218, and slag, which is molten ashes of the coal, descends from the zone 219 to the lower zone 215. The upper stage burner 212 and the lower stage burner 211 are installed with an interval between them sufficient for making the coal 10 and the oxygen 11, which are supplied from the lower stage burner 211, contact the natural gas 20 and the steam, which are supplied from the upper stage burner, after the coal 10 and the oxygen 11 have reacted sufficiently with each other.
Accordingly, a lower stage reacting zone 223, wherein the gasification reaction of coal 10 mainly proceeds, is formed at a lower location inside the reactor, and an upper stage reacting zone 224, wherein the steam reforming reaction of natural gas mainly proceeds, is formed at an upper location inside the reactor. A mass ratio of oxygen/coal supplied from the lower stage burner 211 is made higher than in the case when only coal is supplied for the gasification, in order to ensure a sufficient quantity of heat for steam reforming of the natural gas 20 supplied from the upper stage burner 212.

2i84~3 The heat energy generated by the gasification of coal in the reacting zone 223 can be utilized for the steam reforming reaction of the natural gas in the reacting zone 234 without using any heat exchanger.
The slag trap 220 allows slag to travel into the slag cooling tank 221 to be released from the reactor. The slag 31 released from the reactor is cooled in the cooling tank 221 with water to become solid.
The constriction 222 provided at the outlet portion of intermediate zone 219 of the reactor suppresses release of unburned char from the zone 219 to outside the reactor. The suppression of release of the unburned char and the returning of the char into the zone 219 can prevent a decrease of the gasification ratio of the coal. Furthermore, the constriction decreases the downstream release of solids from the reactor 210, and hence the capacity of the dust removal apparatus 240 can be decreased. Particularly, when a ceramic filter is used as the dust removal apparatus 240, clogging of this filter can be prevented by providing the constriction. Hence the service time of the ceramic filter can be extended, so that a decrease in production costs can be realized.
(Embodiment 3) Another embodiment of the reactor 210 of the H2-CO mixture producing apparatus, using natural gas and coal as raw materials, of the present invention is indicated in FIG. 11.
The whole reactor is composed of refractory material 216 surrounded by the vessel 217, and the reactor is divided into three zones, such as an upper zone 218, an intermediate zone 219 and a lower zone 215. The upper stage burner 212 is installed above the lower stage burner 211. An oxygen supply burner 213 for supplying oxygen is provided between the lower burner 211 and the upper burner 212. A slag trap 220 is located at the lower zone, and a slag cooling tank 221 is located beneath the slag trap. A constriction 222 iS provided at the outlet of intermediate zone. The upper stage burner 212, the lower stage burner 211, and the oxygen supply burner 213 are directed in a tangential direction to the inner wall 21~4~

of the reactor to form whirl flows. Particularly, the oxygen supply burner 213 is arranged so that the whirl flow it forms descends toward the lower part of the reactor. The upper stage burner 212, the lower stage burner 211, and the oxygen supply burner 213 are indicated only as a single row in FIG. 11, but a plurality of these burners can be installed in plural rows.
The coal 10 and the oxidizing agent such as oxygen 11 are supplied into the reactor from the lower stage burner 211 to form a whirl flow, their reaction being enhanced by the whirl flow. Similarly, the natural gas 20 and the steam 22 are supplied into the reactor from the upper stage burner 212 to form a whirl flow, their reaction being enhanced by the whirl flow.
When a sufficient amount of oxygen, whereby the mass ratio of oxygen/coal exceeds 1, is supplied to the reactor, if the whirl flow generated by the lower stage burner is weak, the temperature in the vicinity of the lower stage burner is elevated locally by the combustion reaction of the coal.
Therefore, the oxygen, the amount of which exceeds 1 in the mass ratio of oxygen/coal, is supplied through the oxygen supplying burner 213, so that the region in which the combustion reaction of coal occurs readily, is divided into two zones, respectively in the vicinity of the lower stage burner, and the vicinity of the oxygen supplying burner. In accordance with this improvement, local heating of the inside the reactor to a high temperature can be avoided, so that the load on the materials that form the reactor can be decreased.
Because the oxygen supplied from the oxygen supplying burner forms a whirl flow moving toward the lower stage burner, the oxygen hardly reacts with the natural gas supplied from the upper stage burner, and the reaction of the natural gas with the steam is not disturbed. Other functions of the reactor are the same as the reactor shown in embodiment 2.
(Embodiment 4) Another embodiment of the reactor 210 of the H2-CO mixture producing apparatus, using natural gas and coal as raw 218~53~
-materials, of the present invention is indicated in FIG. 3.
The whole reactor is composed of refractory material 216 surrounded by the vessel 217, and the reactor comprises a coal gasification chamber 231 and a natural gas reforming chamber 232, which are partitioned by a constriction. The coal gasification chamber 231 and the natural gas reforming chamber 232 are respectively provided with a lower stage burner 211 and an upper stage burner 212 for supplying raw materials, which are directed in a tangential direction to the inner wall of the reactor. A slag trap 220 is provided at the lower portion of the reactor, and a slag cooling tank 221 is provided beneath the slag trap. A constriction 222 is provided at the outlet portion of the reactor. The coal and the oxidizing agent supplied into the reactor through the lower stage burner form a whirl flow along the inner wall of the reactor and descend because of the existence of a central constriction 230 located at the middle of the reactor, and turn into an upward stream at the slag trap area.
Accordingly, the retention time of the coal and the oxidizing agent can be ensured, so that the gasification reaction proceeds. Similarly, the natural gas and the steam supplied into the reactor through the upper stage burner form a whirl flow along the inner wall of the reactor and descends because of the existence of the constriction 222 and turn into a straight upward stream at the central constriction 230.
The coal 10 and the oxidizing agent, such as oxygen 11, are supplied to the reactor from the lower stage burner 211 in the coal gasification chamber 231, and the natural gas 20 and the steam 22 are supplied to the reactor from the upper stage burner 212 in the reforming chamber 232. In this situation, if it is desired to decrease the size of the reactor, sufficient distance between the lower stage burner 211 and the upper stage burner 212 could not be obtained. Therefore, in accordance with the present embodiment, the central constriction 230 is provided to effectively separate the chamber 231 where the coal gasification reaction mainly proceeded from the chamber 232 where the natural gas reforming reaction mainly proceeded.
The mass ratio of oxygen/coal supplied from the lower stage burner was selected to be higher than the case when only coal is supplied for gasification, in order to ensure a sufficient amount of heat for reforming the natural gas supplied from the upper stage burner. The reactor shown in the present embodiment can also utilize the heat energy generated by the coal gasification reaction at the lower stage reaction area 223 for the steam reforming reaction of the natural gas proceeding in the upper stage reaction area 224 without using any heat exchanger. It can also use the method shown in embodiment 3.
The functions of the slag trap 220, the slag cooling tank 221 and the constriction 222 are as the same as in embodiment 3.
(Embodiment 5) FIG. 10 illustrates schematically an embodiment of a methyl alcohol producing apparatus, using natural gas and coal as raw materials. The apparatus comprises a coal gasification reactor 280, a dust removal apparatus 240, a desulfurization apparatus 250, a natural gas reforming apparatus 260, and a methyl alcohol synthesizing apparatus 310, which are arranged in the order listed above.
Raw materials are supplied to the coal gasification reactor from a coal supply section and an oxygen supply section. The coal supply section comprises a hopper 110 and a coal supply control valve 111. The hopper 110 stores coal pulverized to under-100 mesh 90~, from which coarse cohesive materials have been eliminated. The atmosphere inside the hopper is pressurized with nitrogen 12 that is a by-product from the oxygen producing apparatus 130. The coal supply control valve 111 controls the supply amount of the raw coal depending on the operating condition of the system.
The oxygen supply section comprises an oxygen producing apparatus 130 and an oxygen supply control valve 131. The oxygen producing apparatus 130 is an apparatus to pressurize 2184~31 and liquefy air by a compressor, and to distill the liquefied air for separating oxygen and nitrogen, the main component of air. The oxygen supply control valve 131 controls the supply amount of the oxygen depending on the operating condition of the system.
The coal gasification reactor 280 comprises a lower stage burner 211 and an upper stage burner for supplying the coal 10, and an oxidizing agent such as oxygen 11, and steam 22, the heat recovery portion 213 for cooling the reacted gas, and a slag cooling tank 221.
The dust removal apparatus 240 uses a dry process for collecting solid dust in the reacted gas, in order not to decrease the temperature of the gas supplied from the coal gasification reactor to a level lower than 900C, which is a necessary temperature for producing the steam reforming reaction of the natural gas in the natural gas reforming apparatus 260, which is installed in the downstream part of the reactor. A cyclone or a ceramic filter can be utilized.
The desulfurizing apparatus 250 uses a dry process, the same as the dust removal apparatus, in order not to decrease the temperature of the gas. The dry process is a method for fixing H2S gas directly by a fine powder of calcium carbonate or zinc oxide.
The methyl alcohol producing division 300 is as the same as the conventional one.
The steam reforming reaction of the natural gas 20 requires a high temperature of 1600C if no catalyst is used.
In accordance with the method shown in embodiment 1, this high temperature is obtained by operating the reactor with a high ratio of oxygen/coal in the coal gasification reactor 280.
However, in this case, the high temperature sometimes exceeds a suitable temperature for the gasification depending on the kind of coal. In accordance with the present embodiment, a catalyst is used in the natural gas reforming apparatus, and the reforming reaction of the natural gas proceeds at about 9oOC. Accordingly, if a temperature about 1000C can be obtained by the coal gasification apparatus, it is sufficient 2~845~1 for the reforming reaction of the natural gas. In this case, although the production cost is high, because respective reactors for the coal and the natural gas must be provided, a high efficiency operation in accordance with the nature of the coal becomes possible. Furthermore, although the coal in the natural gas are not reacted in the same reactor as in embodiment 1, the use of a heat exchanger can be made unnecessary by arranging the coal gasification reactor 280 and the natural gas reforming apparatus 260 in series, so that effective utilization of heat as in embodiment 1 becomes possible.
In accordance with the present embodiment, the conversion ratio of the raw materials to methyl alcohol is approximately 80~. Accordingly, in comparison with the conventional method, an improvement of the conversion ratio by 10 ~ 15~ in absolute value is realized as in embodiment 1.
In embodiments 1 ~ 4, a slurry of coal and water can be used as the raw material for producing the H2-CO mixture instead of coal, and a combination of the coal-water slurry, natural gas, steam, and an oxidizing agent, such as oxygen, can be used as the raw material for producing the H2-CO
mixture. Using the coal-water slurry instead of coal facilitates the handling of the raw materials.

Claims

1. A method for producing a hydrogen (H2)-carbon monoxide (CO) mixture comprising the steps of:
pulverizing coal, and supplying pulverized coal into a first zone of a reactor, located in a downstream region of gas flow from said first zone, with an oxidizing agent for generating hydrogen and carbon monoxide, and further comprising the steps of:
supplying natural gas into a second zone of the reactor with steam for generating hydrogen and carbon monoxide concurrently with supplying said pulverized coal and said oxidizing agent, and discharging generated H2-CO mixture from the reactor.

2. A method as claimed in claim 1, wherein said first zone in the reactor is maintained at a temperature in a range of 900 ~ 1600°C, and. said second zone in the reactor is maintained at a temperature in a range of 800 ~ 900°C with a catalyst, or of 1000 ~ 1600°C without a catalyst.

3. A method as claimed in claim 1, wherein a generating ratio of hydrogen to carbon monoxide is controlled by adjusting supplied amounts of said coal and said natural gas into the reactor.

4. A method as claimed in claim 1, wherein said first zone and said second zone are divided by giving the supplied pulverized coal and the oxidizing agent, and the supplied natural gas and the steam, a whirl flow in a circumferential direction in the reactor, respectively.

5. A method as claimed in claim 1, wherein said first zone and said second. zone in the reactor are divided by a partition having at least a constriction.

6. An apparatus for producing a hydrogen (H2)-carbon monoxide (CO) mixture comprising:
a raw materials supplying equipment comprising a pulverizer, storage tanks for coal, oxygen, natural gas, and water, a steam generator, control valves for regulating the supplied amounts of coal, oxygen, natural gas, and steam, and a reactor comprising a first zone, having at least one inlet for supplying each of the pulverized coal and oxygen, a second zone having at least one inlet for supplying each of the natural gas and steam, and an outlet for discharging the generated H2-CO mixture, a heat recovery device, desulfurization equipment, and dust removal equipment.

7. An apparatus as claimed in claim 6, wherein said second zone is located at a downstream region of gas flow from said first zone.

8. An apparatus as claimed in claim 6, wherein said first zone is provided with means for generating a whirl flow of the supplied pulverized coal, and oxygen streams around the inner circumference of a circular wall of the reactor and said second zone is provided with means for generating a whirl flow of the supplied natural gas, and steam streams around said inner circumference.

9. An apparatus as claimed in claim 8, wherein said means for generating a whirl flow in the first zone is at least one blow-out burner for supplying pulverized coal, and oxygen streams around said inner circumference to generate a whirl flow of a mixture of the pulverized coal and the oxygen in the reactor, and said means for generating a whirl flow in the second zone is at least one blow-out burner for supplying natural gas, and steam streams around said inner circumference to generate a whirl flow of a mixture of the natural gas and the steam in the reactor.

10. An apparatus as claimed in claim 6, wherein a partition having at least a constriction is provided between the first zone and said second zone.

11. An apparatus as claimed in claim 6, wherein the ratio of hydrogen to carbon monoxide in the generated H2-CO
mixture is controlled by regulating the supplied amount of coal and natural gas, respectively, by said control valves.

12. An apparatus as claimed in claim 6, further comprising:
a plurality of burners provided at side walls of the reactor in plural rows along the stream of generated gas, wherein said reactor is composed so that the generated gas flows in one direction, at least one row of said burners in plural rows in the downstream region being so arranged that supply of the coal with the oxidizing agent, and the natural gas with the steam can be varied, the remainder of the burners being so arranged that supply of only the coal with the oxidizing agent is possible, in order to make the reactor possible not only to gasify the coal, but also to perform the reaction of the natural gas with the steam concurrently with the gasification of the coal, and the ratio of hydrogen to carbon monoxide in the generated H2-CO mixture is controlled by regulating the supplied amount of coal and natural gas, respectively, in a case when both the coal and the natural gas are supplied to the reactor.

13. An apparatus as claimed in claim 6, further comprising:
a plurality of burners provided at side walls of the reactor in two rows along the stream of generated gas, wherein said reactor is composed so that the generated gas flows in one direction, the natural gas and the steam are supplied from said burners in a downstream region, and the coal and the oxidizing agent are supplied from said burners in an upstream region, wherein a plurality of oxygen supply nozzles are provided between said burners in the downstream region and said burners in the upstream region, and oxygen supplied into the reactor in an amount of more than 1 in an oxygen/coal ratio by weight is divided into two portions, one portion exceeding 1 in the oxygen/coal ratio by weight being supplied through said oxygen supplying nozzles, and the other portion equal to 1 in the oxygen/coal ratio by weight being supplied through said burners in the upstream region so as to prevent the lower portion of the reactor from local overheating.

14. A method for synthesizing methyl alcohol comprising the steps of:
producing an H2-CO mixture having a generated ratio of H2/CO equal to 2 in accordance with a method claimed in any one of claims 1-5, and synthesizing methyl alcohol from said H2-CO mixture.

15. An apparatus for synthesizing methyl alcohol comprising:
a methyl alcohol synthesizing apparatus for synthesizing methyl alcohol from an H2-CO mixture generated by apparatus claimed in any one of claims 6-12, installed at a rear stage of said apparatus for producing an H2-CO mixture.

16. An apparatus as claimed in claim 13, wherein means for removing hydrogen sulfide in the generated H2-CO
mixture is provided at a stage prior to introducing the H2-CO
mixture into said methyl alcohol synthesizing apparatus.

17. A method for producing methyl alcohol from coal, natural gas, steam, and an oxidizing agent, comprising the steps of:
producing a hydrogen (H2) - carbon monoxide (CO) mixture;
and synthesizing said methyl alcohol from said H2 - CO
mixture, wherein said H2 - CO mixture is produced by:
pulverizing coal; and supplying said pulverized coal into a first zone of a reactor with said oxidizing agent for generating H2 and CO; and supplying said natural gas into a second zone of the reactor, located in a downstream region of gas flow from said first zone, with said steam for generating H2 and CO
concurrently with supplying said pulverized coal and said oxidizing agent.

18. An integrated energy system, wherein production of methyl alcohol and electric power are performed concurrently by installing apparatus for synthesizing methyl alcohol from an H2-CO
mixture, and an electric power generator using the H2-CO mixture as fuel, located at a rear stage of the apparatus for producing said H2-CO mixture as claimed in claim 6.

19. An integrated energy system as claimed in claim 18, wherein means for desulfurization is provided between the apparatus for producing said H2-CO mixture and either one of said apparatus for synthesizing methyl alcohol from said H2-CO
mixture and said electric power generator using said H2-CO
mixture as fuel.

20. A method for operating an integrated system, wherein production of methyl alcohol and electric power generation are performed concurrently by installing apparatus for synthesizing methyl alcohol from an H2-CO
mixture, and an electric power generator using the H2-CO mixture as fuel, located at a rear stage from the apparatus for producing said H2-CO mixed gas, comprising the steps of:
controlling supply amounts of raw materials comprising coal, natural gas, steam, and an oxidizing agent to said apparatus for producing an H2-CO mixture so as to make the composition of the generated gas have a ratio of H2/CO of 2, and supplying said H2-CO mixture to said apparatus for synthesizing methyl alcohol from the H2-CO mixture, when only production of methyl alcohol is performed, controlling supply amounts of raw materials comprising coal, steam, and an oxidizing agent to said apparatus for producing an H2-CO mixture by only coal gasification, and supplying said H2-CO mixture to said electric power generator using the H2-CO mixture as fuel, when only electric power generation is performed, and, controlling supply amounts of coal and natural gas to said apparatus for producing an H2-CO mixture, and distributing an amount of the H2-CO mixture to said apparatus for synthesizing methyl alcohol from the H2-CO mixture and to said electric power generator using the H2-CO mixture as fuel, based on a ratio of methyl alcohol production and electric power generation such as to make the load on said apparatus for synthesizing methyl alcohol from the H2-CO mixture stable in accordance with variation of electric power demand, when both the methyl alcohol production and the electric power generation are performed.