AU694052B2

AU694052B2 - A method for producing hydrogen-carbon monoxide mixed gas, and apparatus thereof

Info

Publication number: AU694052B2
Application number: AU62064/96A
Authority: AU
Inventors: Norio Arashi; Fumihiko Kiso; Shuntaro Koyama; Atsushi Morihara
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1995-08-31
Filing date: 1996-08-14
Publication date: 1998-07-09
Anticipated expiration: 2016-08-14
Also published as: DE19634857A1; JPH0967582A; CN1152021A; AU6206496A; CN1066186C; DE19634857C2; CA2184531A1; CA2184531C

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): Hitachi, Ltd.

ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

INVENTION TITLE: A method for producing hydrogen-carbon thereof monoxide mixed gas, and apparatus The following statement is a full description of this invention, including the best method of performing it known to me/us:- ~,a Ii.

ii I I

CI

4 i~ 1 I C It I ~C C V C- C C C C IC C 114* S CCCI C 0 Backgr.yoUu of. theL .InveL1L.on The present invention relates to a method for producing hydrogen (H 2 -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 mixed gas produced by the 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 to a method using natural gas (main component: CHO), the method can be roughly divided into two kinds: the one is the method using catalyst and another is the method using no catalyst. However, the method using catalyst, such as the one disclosed in JP-A-51--29408 (1976), is mainly used. In accordance with the method using natural gas, the natural gas is treated first with a desulfurizing equipment for removing hydrogen sulfide

(H

2 S) contained in the natural gas. Subsequently, the natural gas, which is desulfurized, and steamn are 2 introduced into a natural gas reforming equipment for obtaining H 2 -CO mixed gas by a reaction of natural gas and steam indicated by the following equation

CH

4

H

2 0 3H 2 CO (1) In a case when catalyst is used, a nickel based catalyst comprising a carrier, such as heat resistant alumina, is used, and a temperature of 800-900 'C is necessary as the reaction condition. The reaction expressed by the equation is an endothermic reaction, and heat must be supplied continuously in order to maintain the necessary temperature for the reaction, i.e.

800 900 OC. Generally, heat of combustion of natural gas, which is expressed by the following equation is utilized as a heat source.

CH

4 202 2H 2 0 CO 2 (2) 20 In a case when catalyst is not used, a high temperature 4 in a range of 1000 1600 OC is necessary for proceeding the I reaction expressed by the equation and the high temperature is obtained by the reaction expressed by the equation in the reactor vessel. In this case, a reaction expressed by the equation also proceeds in the natural gas reforming equipment.

V ,C5 SI tc c

I

3

CH

4 +CO-2H 2 +2CO (3) The generated H 2 -CO mixed gas is introduced into a methyl alcohol synthetic equipment for synthesizing methyl alcohol by the reaction expressed by the equation 2H 2 CO CH 3 OH (4)

C..

''CC

C C( CC C

CCC

C C Where, the composition of the H 2 -CO mixed gas obtained from the natural gas by the reaction expressed by the equation is stoichiometrically [H 2 3, while the composition of the H 2 -CO mixed gas suitable for synthesizing methyl alcohol by the reaction expressed by the equa-ion is 2. Therefore, the composition of the H 2 -CO mixed gas must be adjusted in order to proceed effectively the reaction. Generally, a shift reaction expressed by an equilibrium equation is used for converting H 2 to CO.

CO H2O CO 2

H

2 Here, because the reaction proceeds in order to convert the composition of the H 2 -CO mixed gas obtained 25 from the natural gas from [H 2 3 to 2, a part of H 2 must be converted to CO by adding CO 2 One of the general methods for obtaining CO 2 in a commercial K 4 scale is a pyrolysis of lime stone (CaCO 3 However, the pyrolysis of lime stone is not effective only for production of CO0, but economical only when, for instance, 4 calcium hydroxide (Ca (OH) 2 is produced concurrently.

Accordingly, the shift reaction, wherein C0 2 is added, is scarcely utilized in the methyl alcohol production plant except a case when a CO 2 production plant locates nearby. Generally, the excess hydrogen at the methyl alcohol synthesis is separated with other residual H 10 gases from methyl alcohol, and utilized as fuel for a steam heating equipment. That means, energy of the excess 1P hydrogen is once converted to thermal energy, and transferred to energy of steam via a heat exchanger.

Accordingly, a large loss of energy can not be avoided. In accordance with the reason explained above, a converting efficiency, which is a 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 20 converting efficiency can not be expected theoretically.

*A 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 *ISI organic compound composed of oxygen, sulfur, nitrogen, Ii 1 and ashes in addition to carbon and hydrogen. However, if it is simplified as CH, the gasification reaction of coal is essentially expressed by the equation 2CH 02 2CO H 2 (6) In order to gasify coal, the coal gasification reactor must be maintained at a temperature in a range of 900 1600 0 C, but no heat source is necessary, because the reaction expressed by the equation is an exothermic reaction. However, if the exhaust heat is not utilized, an energy utilization efficiency can not be improved. The gas exhausted from the coal gasification reactor contains fly ash and H 2 S. The fly ash is recovered by a dust removal equipment, and H 2 S is moved by a desulfurization equipment. The composition of H 2 -CO mixed gas obtained from coal by the reaction expressed by the i equation is stoichiometrically [H 2 0.5. The composition suitable for synthesizing methyl alcohol from H 2 -CO mixed gas is [H 2 2 as expressed by the Sequation and the value is larger than the ratio of

[H

2 3/[CO] in the H 2 -CO mixed gas obtained by the coal gasification. Therefore, the composition of the H 2

-CO

mixed gas obtained by the coal gasification must be 25 converted in order to produce methyl alcohol. The shift reaction expressed by the equation is used for the conversion. In this case, a part of CO is converted to conversion. In this case, a part of CO is converted to 6

H

2 by adding H 2 0. Temperature drop in the system can not be avoided in accordance with addition of H 2 0, 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 cover a& methyl alcohol. Theoretically, the exhaust heat at the coal gasification can not be reduced to approximately less than 20 of energy of the coal, nor can the exhaust heat at producing methyl alcohol from

H

2 CO mixed gas be reduced to approximately less than 15 of energy of the H 2 -CO mixed gas. In accordance with the above reason, a ratio of energy converted to methyl alcohol to the total energy of the coal, that is, a 15 conversion ratio is approximately 65 and a significant improvement to more than 65 can not be expected theoretically.

In accordance with the conventional producing method of methyl alcohol using natural gas or coal as a 20 raw material, a significant increase in efficiency was theoretically impossible even if the most extensive improvement was performed for increasing the conversion ratio to methyl alcohol from the raw material. One of the reason is that the composition of the H 2 -CO mixed gas suitable for production of methyl alcohol must have the ratio of [H 2 while the H 2 -CO mixed gas obtained from natural gas has the ratio of [H 2 3 and the i..

.4" I I:: Q:\OPRMJC\=06-96.SPE- 11/3/9 -7-

H

2 -CO mixed gas obtained from coal has the ratio of

[H

2 Another reason is that the exhaust heat can not 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.

Summary of the Invention One of the preferred objects of the present invention is to provide a method to produce H 2 -CO mixed gas having an arbitrary ratio of [H 2 in a range of 0.5 3. Another preferred object of the present invention is to provide a novel method for producing methyl alcohol using the above method to produce H 2 -CO mixed gas, which can break 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.

oo" Further, another preferred object of the present H invention is to provide an integrated energy system, which is 20 capable of using the above novel method for producing methyl s alcohol, and of responding to variation of power demand in maintaining the load to the H 2 -CO mixed gas production plant So: stable in concurrent production of methyl alcohol and electric I power.

25 Accordingly the present invention provides a method for producing hydrogen (H2) -carbon monoxide (CO) mixed gas comprising the steps of: S pulverising coal, and S supplying pulverised coal into a first zone of a reactor with an oxidizing agent for generating hydrogen and carbon monoxide, wherein 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 mixed gas from the reactor, Q:\OPER\MC62064-96.SPE 1/319 7A Swherein a generating ratio of Hydrogen to carbon monoxide is controlled to a specified value within the range of 0.5 to 3 by adjusting supplying amounts of said coal and said natural gas into the reactor.

In another aspect the present invencion provides an apparatus for producing hydrogen (H 2 )-carbon monoxide (CO) mixed gas comprising: a raw materials supplying equipment comprising a pulveriser, storage tanks for respective of coal, oxygen, natural gas, and water a steam generator, and control valves for regulating the supplying amounts of respective of coal, oxygen, natural gas, and steam, a reactor comprising a first zone, which comprises at least one inlet respectively for supplying each of pulverized coal and oxygen, a second zone, which comprises 20 at least one inlet respectively for supplying each of natural gas and steam, and an outlet for discharging the generated H 2 -CO mixed gas, a heat recovery device, a desulfurization equipment, and 25 a dust removal equipment, wherein the generating ratio of hydrogen to carbon monoxide in the generated H 2 -CO mixed gas S' is controlled to a specified value within the range of 0.5 to t |3 by regulating the supplying amount of coal and natural gas, respectively, by said control valves.

S. i QA\OPERNMJC\62O64.96.SPE -11308 i \t I r t. C Furthermore, the heat efficiency is capable of being improved and the heat exchanger was omitted by reacting the coal with oxygen, and the natural gas with steam in the same reactor.

Theoretical background for determining operating conditions of the system is explained in detail hereinafter.

When coal, natural gas, oxygen, and steam are supplied into a reactor simultaneously, the reaction with 10 the coal does not proceed. Because, natural gas, oxygen, and steam are in a gaseous condition, while only the coal is solid. In comparison of reactivity of oxygen and steam with natural gas, the reactivity of oxygen with the natural gas is larger than that of steam. Accordingly, 15 a combustion reaction expressed by the equation wherein the natural gas is combined with oxygen, proceeds prior to the steam reforming reaction expressed by the equation wherein the natural gas reacts with steam to generate carbon monoxide.

CH

4

H

2 0 3H 2

CO

CH

4 202 2H 2 0 CO 2 (7) (8) When the reaction expressed by the equation (8) occurs, generated H 2 0 and CO 2 must be reduced to H 2 and 9 CO. Therefore, the reaction expressed by the equations and that is, reactions of H 2 0 and COz 2 with char (carbon component, coal without volatile) can be used.

C H20 H 2 CO. (9) C CO 2 2CO However, the char is utilized and consumed for reducing C0 2 which is usually contained in volatile of coal, and H 2 0 and CO 2 generated by oxidation of H 2 and CO, which are contained in the volatile of coal. Therefore, the char can not be utilized for reducing H 2 0 and CO 2 generated by the reaction expressed by the equation In accordance with the above reason, when coal and natural gas react in the same reactor, a suitable designing of the reactor and an adequate setting of the S. operating condition become necessary so that the natural (i gas does not cause the combustion reaction expressed by the equation but only the steam reforming reaction S' 20 expressed by the equation proceeds.

First, the reaction with coal is explained i" hereinafter. An example of coal composition, for instance pacific ocean coal, is indicated in Table 1.

r r Ki '4.

t 4 4 Table 1 Composition of coal (Pacific ocean coal) Industrial analysis Wt. Moisture 2.8 Ashes 14.4 Volatile 45.2 Fixed carbon 37.6 Element analysis daf Carbon 77.82 Hydrogen 6.73 Nitrogen 1.09 Sulfur 0.05 Oxygen 14.32 11 S* 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, volatile, fixed carbon, and ashes in accordance with the above industrial analysis. The moisture is evaporated by heating the coal, and the volatile and char, of which main component is carbon, are separated by pyrolysis. The industrial analysis is performed under an atmosphere, but the I 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 an atmosphere, V 1 atm [wt. obtained by the industrial analysis by the following mathematical equation SV=V 1 atm (-0.0661ln Pt) (Math. 1) where, fc. Pt: Pressure in the reactor [atm] In accordance with the present invention, the pressure in the reactor is set at 30 [atm] The volatile react with oxygen to generate C0 2 and H 2 0. This reaction can be expressed by the following equation (11):

I

~I

*4tU tt 14< 4' (7 12 CaHbOcNdSe (Y 02 f C (Char) (b-2e) /2 H 2 0 e H 2 S d/2 N 2 (2 -c 2 (b -2e) CO (c 2 CZ- (b -2e) /2 C0 2 (11) In accordance with the present invention, steam reforming of natural gas is concurrently performed in the same reactor~ by supplying natural gas and steam. However, the reforming reaction is an endothermic reaction, and in a case when a large amount of natural gas is supplied, the heat generated only by the reaction expressed by the equation (11) becomes insufficient. At that case, the supplying amount of oxygen is increased to burn a part of carbon monoxide as shown by the equation (12) to supply additional heat: 02 -+2CC 2 (12) The above reactions can be regarded to proceed 20 instantaneously. The residual char is solid, and the char is gasified by the reaction with H 2 0 and C0 2 which are generated by combustion of the volatile, as indicated by the following equations (13) and (14): C (Char) H 2 0 H 2

CO

C (Char) C0 2 "2C0 (13) (14) 12 CaHbOcNdSe (b-2e)/2 (2 (a-f) 2 a a 02 fC(Char) H20 e H 2 S d/2 N 2 c 2 a (b 2e)/2) CO (b 2e) /2 C02 "Itr I r (11) In accordance with the present invention, steam reforming of natural gas is concurrently performed in the same reactor by supplying natural gas and steam. However, the reforming reaction is an endothermic reaction, and in a case when a large amount of natural gas is supplied, the heat generated only by the reaction expressed by the equation (11) becomes insufficient. At that case, the supplying amount of oxygen is increased to burn a part of carbon monoxide as shown by the equation (12) to supply additional heat: 2CO 02 2C0 2 (12) The above reactions can be regarded to proceed 20 instantaneously. The residual char is solid, and the char is gasified by the reaction with H 2 0 and CO 2 which are generated by combustion of the volatile, as indicated by the following equations (13) and (14): C (Char) H20 H 2

CO

C (Char) CO 2 2CO (13) (14) 1 i 13 However, these reactions can not be deemed to proceed instantaneously, and a part of the char will remain ungasified if a sufficient residence time can not be available. Therefore, in designing the reactor, a relationship between carbon conversion ratio of carbon in the char and reaction time must be grasped. The relationship between the carbon conversion ratio, Xchar of carbon in the char and the reaction time, 0 can be expressed by a model shown by the following mathematical equations and r, i t *1 t ~rr "cce c 4'r.

P Char D P sP +P

CO

2 H20 1 1 -Xc r k react XChar 3kGas (Math. 2) k rt=247exp(-21 0 6 0 100 T1 (Math. 3) ct t C( 14 T 0. k a=8.725X1 P1D0 k 2000 GasP D (Math. 4) Ii> l.

CL

S. S

C

*4LC C C Where, pCO 2 Partial pressure of CO2 pH20 Partial pressure of H 2 0 P char Density of char Dp Particle size of the char kreat Reaction rate constants of the reactions (13) and (14) koas Diffusion coefficient In accordance with a 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 20 time of the coal and the oxygen in the reactor requires a few seconds in order to obtain a gasification ratio of the coal of at least 0.9. A 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. As explained above, natural gas and steam is loaded into the reactor under a condition wherein the reactions expressed by the equations (14) have been sufficiently proceeded. Therefore, the combustion of natural gas expressed I the equation (15) does not occur.

CH

4 202 4~ 2H 2 0 CO Accordingly, an equilibrium of the steam reforming reaction of natural gas expressed by the equation (16) and the shift reaction expressed by the equation (17) must be considered at the top of the reactor.

CH

4

H

2 0 3H 2 CO (16) CO H 2 0 H2 CO (17) If a partial pressure of respective gas at the top i. of the reactor is expressed as hydrogen p [atm], carbon dioxide q [atm] steam r [atm] carbon monoxide s [atm] and methane t [atm], an equilibrium constant of the steam 20 reforming reaction of methane expressed by the equation (16) is expressed as K1, and an equilibrium constant of "..the shift reaction expressed by the equation (17) is expressed as K2, the equilibrium can be expressed by the following mathematical equations and pXs tXr =K1 (Math. r X s (Math. 6) K2 Where, the equilibrium constants at various temperature are shown in Table 2. The values shown in Table 2 were calculated by the following equations (8) S(11), because a thermodynamic theory indicates that an equilibrium constant of a chemical reaction expressed by the mathematical equation can be calculated by the mathematical equations (11) V i Ai 0 (Math. 7) 20 where, Ai Chemical formula of component I V A stoichiometric coefficient of the component I (It is defined as positive for the raw group and negative for the product group) r~or 1 17 Table 2 Equilibrium constant Temperature K1 K(2 800 3.07E-02 2.43E-01 900 1.27E+00 4.47E-01 1000 2.55E+01 7.17E-01 1100 3.01E+02 1.05E+00 1200 2.36E+03 1.42E+00 1300 1.36E+04 1.82E+00 1400 6.08E+04 2.24E+00 1500 2.23E+05 2.67E+00~ 1600 6.94E+05 3.1OE+0L.

1700 1.89E+06 3.52E+00 1800 4.60E+06 3.93E+00

LA

C

*.tC

C

tilt 4s*~ I nK 2 n RT f (Math. 8) n(KT=- I( i .(Zv-Aj Hf j' i(TZ -v (J i(T)-J j To) 1 (Math. 9) I a 3 T+ t C V (Math. J I n T T 2 -T 3 2 6 +12 (Math. 11) Where,

K

2 98 Equilibrium constant II)at 298.15 [K] KT:Equilibrium constant H)at a temperature T I

S

4E To The standard temperature 298.15 T Temperature [K] A Gfi' Standard Gibbs energy of formation of a component i [J/mol] A Hfi Standard heat of formation of a component i [J/mol] Lvi Heat of vaporization of a component i at To [K] aj, bi, ci, di A coefficient of heat capacity at a constant pressure of a component i [J/(mol'K)] A relationship between the oxygen/coal ratio and 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, conditions for reacting coal, 20 natural gas, oxygen, and steam in a reactor to generate

H

2 -CO mixed gas having a ratio [H 2 equal to 2, and synthesizing methyl alcohol are shown in FIG. 7. The loaded mass ratio of oxygen/coal is making as 1.2. In accordance with the above reactions, a reacted gas, having 25 a composition of [H 2 20 [H 2 0] 15 [CO] 43 [CO2] 21%, at 1500 OC can be obtained. By adding natural gas 1 and steam to the reacted gas, a reacted gas, having Cr 'i a composition of [H 2 48 [H 2 0] 19 [CO] 24

[CO

2 6 at 1000 cC can be obtained. This composition of the gas is suitable for synthesizing methyl alcohol.

In order to recover exhaust heat of the downstream from the reactor, the mass of steam loaded to the reactor is preferably small. When making the ratio of [mass of steam]/[mass of natural gas] 1.5, a mixed gas having a composition of [H 2 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.

In order to obtain a mixed gas having a composition of [H 2 equal to 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.

In accordance with the present invention, a power g.e 'generating equipment was installed in parallel with the 4 methyl alcohol producing equipment at the downstream region of the H 2 -CO mixed gas producing equipment. With the above system, a rate of operation of the H 2 -CO mixed gas producing equipment was kept at a constant rate, and a supplying proportion of the H 2 -CO mixed gas to the methyl l t alcohol producing equipment and the power generating equipment was varied corresponding to the variation in power demand. Depending on the availability factor of the system, that is, rates of operation of the power h'- 21 generating equipment and the methyl alcohol producing equipment, most economical amounts of supplying coal, natural gas, oxygen, and steam were calculated, and the supplying amount of the raw material was controlled to be as same as the calculated values. Practically, the adjustment was performed as follows: When only methyl alcohol production is performed, the supplying amount of the raw materials are controlled so as to obtain the mixed gas having the ratio [H 2

J

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 supplied to the power generating equipment as fuel for power generation. When only power generation is performed, supplying the natural gas is stopped, and power is generated using a gas generated from coal and oxidizing agents.

In accordance with the present invention, the composition of the H 2 -CO mixed gas for synthesizing methyl alcohol can be controlled without performing the shift reaction, and accordingly, effective utilization of energy can be realized. In a case when the coal and the natural gas are treated in the same reactor, any heat exchanger to supply heat for reforming the natural gas becomes unnecessary, and simultaneously, decreasing cost 1 22 for producing methyl alcohol can be realized by decreasing the number of members in keeping a high energy utilization factor. The efficiency of producing methyl alcohol can bu increased by 10"-15 in absolute value from a theoretical limit of conventional methyl alcohol production by producing methyl alcohol with the mixed gas having the ratio [H 2 2 generated by the method of the present invention.

Furthermore, in accordance with the system wherein the power generating equipment is installed in parallel with the methyl alcohol producing equipment, the load for coal gasification can be kept stable with corresponding to the variation in power demand.

Depending on the availability factor of the system, that is, rates of operation of the power generating equipment and the methyl alcohol producing equipment, 41 most economical amounts of supplying coal, natural gas, oxygen, and steam can be calculated, and the supplying amount of the raw material is controlled to be as same as the calculated values.

The high efficiency methyl alcohol producing system using coal and natural gas according to the present invention can realize a significant energy Saving effect when the energy is transported by sea for a long distance.

That means, in comparison with transportation of solid coal, rind transportation of natural gas, which is necessitated to liquefy the gas, when the above materials 23 are converted to methyl alcohol, handling becomes easy and mass transportation by tankers, which are practically used in conventional transportation of oil, becomes possible.

Brief Description of the Drawings These and other objects, features and advantages of the present invention will be understood more clearly from the following detailed description with reference to the accompanying drawings, wherein, FIG. 1 is a schematic illustration indicating a composition of an integrated energy system comprising a

H

2 -CO mixed gas producing equipment using natural gas and i coal as raw materials relating to the present invention, a methyl alcohol producing equipment, and a power generating equipment, FIG. 2 is a schematic cross section indicating an embodiment of a reactor for realizing the H2-CO mixed gas 20 producing equipment using natural gas and coal as raw materials, FIG. 3 is a schematic cross section indicating another embodiment of a reactor for realizing the H 2 A CO mixed gas producing equipment using natural gas and coal as raw materials, ji FIG. 4 is an illustration for explaining a mechanism of gasification of coal, 24 FIG. 5 is a graph indicating a relationship between a ratio of oxygen/coal loaded into the H 2 -CO mixed gas producing equipment of the present invention and a gas composition at a lower step of the reactor, FIG. 6 is a graph indicating a relationship between a ratio of oxygen/coal loaded into the H2-CO mixed gas producing equipment of the present invention and a gas composition at an upper step of the reactor, FIG. 7 is an illustration indicating an optimum operating conditions of the methyl alcohol producing equipment of the present invention, FIG. 8 is a graph indicating a relationship between a composition of loaded raw material and a composition of H 2 -CO mixed gas at the H2-CO mixed gas producing equipment of the present invention, FIG. 9 is a graph for explaining a method for 04. effectively operating the integrated energy system which I comprises a methyl alcohol producing equipment using natural gas and coal as raw materials relating to the jI> 20 present invention, and a power generating equipment, I FIG. 10 is a schematic illustration indicating a composition of a methyl alcohol producing equipment using a H 2 -CO mixed gas producing equipment relating to the 4..

present invention, which uses natural gas and coal as raw materials, and FIG. 11 is a schematic cross section indicating another embodiment of the relating to the present 1 -UYIIIIII.

invention.

Description of the Preferred Embodiments Hereinafter, an embodiment of the present invention is explained referring to drawings.

(Embodiment 1) FIG. 1 indicates an integrated energy system in accordance with the present invention. The system comprises a raw material supply division 100, a H 2

-CO

mixed gas 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 110 supplies coal 10, natural gas oxygen 11, and steam 22 to the H 2 -CO mixed gas producing division 200. The produced H 2 -CO mixed gas is distributed to the methyl alcohol producing division 300 and the power tIt generating division 400 by the gas distributing division 20 500 in order to supply both methyl alcohol and electric power.

The structures of the above divisions are explained respectively in detail, hereinafter.

It The raw material supply division 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 -uo YI~-UP c a coal supply control valve 11. 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 atmosphere inside the hopper with nitrogen 12 which is a by-product from an oxygen producing apparatus 130. The coal supply control valve 111 is a valve to control a supplying 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 and liquefy air by a compressor, and to distill the liquefied air for separating oxygen and nitrogen, a main component of air. The oxygen supply control valve 131 is a valve to control a supplying 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 naturally supplied directly through a piping line. However, the natural gas storage tank is a facility to store extra natural gas for preparing a stable operation of the methyl alcohol producing apparatus with a predetermined load when supply of the natural gas through the pipe line becomes unstable. The natural gas supply control valve 121 is a valve to control a supplying amount of the natural gas t~ r tr~ L

I

L

I

si 1 27 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 a supplying amount of the steam depending on the operating condition of the system.

The H 2 -CO mixed gas producing division 200 comprises the reactor 210, a dust removal apparatus 240, and a desulfurizing apparatus 250.

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 tap 221 for collecting slag which is generated by fusing ashes component of the coal.

The dust removal apparatus 240 is an apparatus for collecting solid dust in the reacted gas, and practically, a cyclone, or a ceramic filter can be used.

The desulfurizing apparatus is an apparatus for removing H 2 S gas in the reacted gas, and, for instance, a method of so-called selexol process can be utilized.

In accordance with the selexol process, H 2 S gas is

A

28 41.

U

absorbed once into an organic solvent, the absorbed H 2

S

is extracted from the solution when concentration of H 2

S

in the solution becomes high, the extracted H 2 S gas having a high concentration is oxidized to SO 2 and the S02 is removed by fixing as gypsum by reacting with a slurry of calcium carbonate, which is a conventional method used in coal fired power plants. A dry desulfurization method wherein H 2 S gas is directly fixed with fine particles of calcium carbonate, zinc oxide, or the like.

The methyl alcohol producing division 300 comprises a methyl alcohol synthesizing apparatus 310, a methyl alcohol distillation section, and a heat exchanger. The methyl alcohol synthesizing apparatus 310 is apparatus for synthesizing methyl alcohol from the H 2 -CO mixed gas, and a catalyst such as ZnO group catalyst can be utilized.

The reaction condition is about 300 OC 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 a 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 an apparatus 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 a

I

I t 29 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 H 2 -CO mixed gas with air 60 pressurized by a compressor, and a turbine is driven by the combustion gas to generate electric power. The heat recovery steam generator 420 is an apparatus to recover heat energy from the combustion exhaust gas 65 of the gas turbine 410 in a form of steam 67. The steam turbine 430 is driven by the steam 67 obtained from the heat recovery steam generator 420, and generates electric power.

Operating conditions of the system in the present embodiment are explained hereinafter.

The operation conditions must be determined so that .II coal and natural gas can react in a same reactor. If coal, E~t natural gas, oxygen, and steam are mixed together and supplied into the reactor at a same time, the reaction of coal can not proceed, because natural gas, oxygen, and steam are gases, but only coal is solid body. In comparison of reactivity of natural gas and water with that of natural gas and oxygen, the reactivity of natural gas and oxygen is high. That means, a combustion reaction expressed by the equation wherein natural gas combines with oxygen, proceeds first before a steam reforming reaction expressed by the equation (18), wherein natural gas combines with steam to generate carbon monoxide, occurs.

CH4 H 2 0 3H 2 CO (18)

CH

4 202 2HO 2 0 CO 2 (19) Therefore, when making coal and natural gas react in the same reactor, an operating condition must be controlled so that natural gas does not cause the combustion reaction expressed by the equation but proceeds the steam reforming reaction expressed by the equation (18) In accordance with the present invention, the coal and the oxygen were supplied into a reactor at a lower portion of the reacvor, and the natural gas and the steam were supplied into the reactor at an upper portion of the reactor. Shapes of the reactor, methods for supplying raw materials, and a ratio of supplied coal and oxygen were i considered so that the coal and the oxygen supplied from the lower portion into the reactor react sufficiently, if it is expressed by a ratio of gaseous carbon to total carbon in the coal, the ratio is at least 0.9, before contacting with the natural gas and the steam supplied from the upper portion into the reactor. Practical composition and function of the reactor are explained in detail in the embodiments 2 and 3.

In order to form swirl flows of coal and natural gas I I 31 in the reactor, upper burners and lower burners were arranged respectively so as to orient to a direction tangential to the inner wall of the reactor. In accordance with the method explained above, the H 2 -CO mixed gas having a ratio, [H 2 of 2 was produced, and methyl alcohol was prepared from the H 2 -CO mixed gas.

In accordance with the present invention, when methyl alcohol is prepared from 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 a 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 15 in an absolute value becomes possible.

An example of operation of the system is explained hereinafter.

Pulverized coal 10 is supplied from a hopper 110 into a reactor 210 of H 2 -CO mixed gas producing division 200 through a coal supply control valve 111 and a lower stage burner 211. Oxygen 11 is produced at an oxygenr producing apparatus 130 and supplied into the reactor 210 of the

H

2 -CO mixed gas producing division 200 through an 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 Sj 0r 32 liquefied air, is used for pressurizing the pulverized coal 10. Both natural gas 20 stored in a natural gas storage tank 120 of a raw material supply division 100, and steam 22 heated by heat recovered from the reactor 210 by a heat recovery portion 213, are supplied into the reactor 210 of the H 2 -CO mixed gas producing division 200 through a respective of a natural gas supply control valve 121 or a steam supply control valve 141, and an upper stage burner 212. The reactor 210 shown in FIG. 2 is used, which is provided with the lower stage burner 21 and the upper stage burner 212 respectively at places separated mutually with a long distance so that a certain retention time can be insured before contacting a 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 f. at a middle portion of the reactor 210, can also be useful.

Slag, which is fused from coal in the reactor, can I. be recovered at a slag tap 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 by a dust removal apparatus 240 for removing dust, and a desulfurizing apparatus 250 for removing H 2

S.

The cleaned H 2 -CO mixed gas 40 is distributed by a gas distributor 500 to the methyl alcohol producing division 300 and the electric power generating division 400.

At the methyl alcohol producing division 300, crude

L\

33 methyl alcohol 50 is synthesized from the H 2 -CO mixed gas 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 be 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 at a 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 electric power generation division 400. Exhaust heat at the methyl alcohol synthesis is recovered by a heat exchanger 350, and utilized at the second distillation column 360 using the heat exchanger 360.

,jj ,At the electric power generation division 400, the

H

2 -CO mixed gas 40 is burnt with compressed air -60 to drive a gas turbine 410 and generate electric power. Exhaust gas of the gas turbine 410 is recovered by a heat recovery steam generator 420 as steam 67, and the steam 67 is used for driving a steam turbine 430 to generate electric power.

Next, a method for supplying raw materials to the i system is explained hereinafter.

When only methyl alcohol is produced, the H 2 -CO mixed gas 40, having a ratio [H 2 of 2 suitable for producing methyl alcohol, is produced at the H 2 -CO mixed gas producing division 200 using coal 10, an oxidizing agent such as oxygen 11, natural gas 20, and steam 22.

All of the H 2 -CO mixed gas is supplied to the methyl alcohol producing division 300 through the gas distribution 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 H 2 -CO mixed gas is produced at the H 2 -CO mixed gas producing division 200 using coal 10, which is cheaper than natural gas, an oxidizing agent such as oxygen 11, and steam 22. The generated H 2 -CO mixed gas is supplied to the electric power generation division 400 through the gas distribution apparatus 500, and electric power is generated. In this case, the supplying amount of coal can be increased by making the upper stage burner changeable from natural gas supply to coal supply, and vice versa.

When both methyl alcohol and electric power are produced, a ratio of the natural gas 20 supply to the coal 10 supply is decreased to smaller than the case when only methyl 20 alcohol is produced in order to decrease cost of the electric power generation. In this case, composition of the H 2 -CO mixed gas 40 has a ratio [H 2 of smaller than 2, and unreacted CO gas 52 is generated in the methyl alcohol synthesis. The unreacted CO gas 52 is separated from methyl alcohol at the first distillation column 320, and supplied to the electric power generation division 400 after heated by the heat exchanger 340 to utilize for 4 i ;o -k electric 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 a relationship of an operation ratio of the methyl alcohol producing apparatus and the electric power generation apparatus to the supplying amount of raw materials (natural gas/coal, oxygen/coal) (Embodiment 2) An embodiment of the reactor 210 of the H 2 -CO mixed 4 gas producing apparatus, using natural gas and coal as raw materials, of the present invention is indicated in FIG. 2. The whole reactor 210 is composed of refractory materials 216 surrounded with vessel 217, and the reactor can be divided into three zones, such as an upper zone :t 218 of the reactor, an inside zone 219 of the reactor, and a lower zone 215 of the reactor. Upper stage burners 212 are installed at the upper zone, and lower stage 4C burners 211 are installed at the lower zone of the reactor.

A slag tap 220 is provided at the lower zone of the reactor 210, and a slag cooling tank 221 is provided beneath the slag tap. A constriction 222 is provided at the outlet portion of inside the reactor. The upper stage burners 212 and the lower stage burners 211 were arranged in a tangential direction to the inner wall of the reactor so as to form whirl flow as indicated in FIG. 2. Generally, plurality of the upper stage burners and the lower stage tC*' c r C burners are provided along circumferential of the reactor.

In FIG. 2, although respective of the upper stage burner and the lower stage burner is indicated only a single row, the respective of the upper stage burners and the lower stage burners can be arranged in plural rows.

The coal and the oxidizing agent supplied into inside the reactor from the lower stage burners form a whirl flow, and their reaction is 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, and their reaction is enhanced by the whirl flow.

Next, function of the present embodiment is explained hereinafter. The coal 10 and the oxidizing agent such as oxygen 11 are supplied into the reactor from the lower stage burners 211, and the natural gas 20 and the steam 22 are supplied into the reactor from the upper stage burners 212. Reacted gas ascends from the inside 219 of the reactor to the upper zone 218 of the reactor, and slag, which is molten ashes of the coal, descends from the inside 20 219 of the reactor to the lower zone 215 of the reactor.

The upper stage burners 212 and the lower stage burners 211 are installed with an interval sufficient for making the coal 10 and the oxygen 11, which are supplied from the lower stage burners 211, contact with the natural gas 20 and the steam, which are supplied from the upper stage burners, after the coal 10 and the oxygen 11 has been reacted sufficiently each other.

Ai 37C I I 37 Accordingly, a lower stage reacting zone 223, wherein a gasification reaction of coal 10 proceeds mainly, is formed at a lower portion inside the reactor, and an upper stage reacting zone 224, wherein a steam reforming reaction of natural gas proceeds mainly, is formed at an upper portion inside the reactor. A mass ratio of oxygen/coal supplied from the lower stage burners 211 is made higher than 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 burners 212.

In accordance with the reactor 210 of the present embodiment, the heat energy generated by the gasification of coal in the lower stage reacting zone 223 can be utilized for the steam reforming reaction of the natural gas in the upper stage reacting zone 234 without using any heat exchanger.

The slag tap 220 installed at the lower zone of the reactor 210 leads slag, which is generated by melting ashes of the coal, into the slag cooling tank 221, which is installed beneath the slag tap, to release from the reactor. The released slag 31 from the reactor is cooled in the slag cooling tank 221 with water to be solid.

The constriction 222 provided at the outlet portion of inside the reactor suppresses release of unburned char from inside 219 to outside the reactor. The suppression of release of the unburned char and returning the char *t r r e r, r if s r r 1 a ,r r a E a;I((

L

I

FCSII

38 into inside 219 the reactor can prevent decrease of the gasification ratio of coal. Furthermore, the constriction decreases release of solid bodies from the reactor 210 to downstream, and accordingly, a capacity of the dust removal apparatus 240 which is install in the downstream can be decreased. Particularly, when a ceramic filter is used as the dust removal apparatus 240, clogging of the ceramic filter can be prevented by providing the constriction, and accordingly, a duration time of the ceramic filter can be extended, and an advantage to decrease production cost significantly can be realized.

(Embodirrment 3) Another embodiment of the reactor 210 of the H2 15 CO mixed gas 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 materials 216 surrounded with vessel 217, and the reactor can be divided into three zones, such as an 20 upper zone 218 of the reactor, an inside zone 219 of the reactor, and a lower zone 215 of the reactor. Upper stage burners 212 are installed at the upper zone, and lower stage burners 211 are installed at the lower zone of the reactor. Oxygen supply burners 213 for supplying oxygen 25 are provided between the lower stage burners 211 and the upper stage burners 212. A slag tap 220 is provided at the lower zone of the reactor 210, and a slag cooling tank i 39 221 is provided beneath the slag tap. A constriction 222 is pro ,ided at the outlet portion of inside the reactor.

The upper stage burners 212, the lower stage burners 211, and the oxygen supply burners 213 were arranged in a tangential direction to the inner wall of the reactor so as to form whirl flow. Particularly, the oxygen supply burners were arranged so that the formed whirl flow descends toward lower stage of the reactor. The upper stage burners 212, the lower stage burners 211, and the 4 oxygen supply burners 213 are indicated only a single row in FIG. 11, but plurality of the above burners can be installed in plural rows.

Next, function of the present embodiment is explained hereinafter. The coal 10 and the oxidizing agent such as oxygen 11 supplied into inside of the reactor from the lower stage burners 211 form a whirl flow, and their reaction is enhanced by the whirl flow. Similarly, the natural gas 20 and the steam 22 supplied into the reactcr from the upper stage burners 212 form a whirl flow, and their reaction is enhanced by the whirl flow.

When a sufficient amount of oxygen, whereby a mass .ratio of oxygen/coal exceeds 1, is supplied to the reactor, rL if the whirl flow generated by the lower stage burners is weak, the temperature in the vicinity of the lower stage burners is elevated locally by the combustion reaction of the coal. Therefore, the oxygen, of which amount exceeds 1 in the mass ratio of oxygen/coal, is supplied L I through an oxygen supplying burner 213, so that a region, wherein the combustion reaction of coal occurs readily, is divided into two zones such as the vicinity of the lower stage burners, and the vicinity of the oxygen supplying burners. In accordance with the above improvement, a local heating of inside the reactor to a high temperature can be avoided, and a load on the metals which compose the reactor can be decreased. Because the oxygen supplied from the oxygen supplying burners forms a whirl flow moving toward the lower stage burners, the oxygen hardly react with the natural gas supplied from the upper stage burners, 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 the embodiment 2.

(Embodiment 4) Another embodiment of the reactor 210 of the H 2 CO mixed gas producing apparatus, using natural gas and coal as raw materials, of the present invention is indicated in FIG. 3. The whole reactor is composed of refractory materials 216 surrounded with vessel 217, and the reactor comprises a coal gasification chamber 231 and a natural gas reforming chamber 232, which are partitioned by a constriction. Respective of the coal gasification chamber 231 and the natural gas reforming chamber 232 is provided with lower stage burners 211 and upper stage burners 212 for supplying raw materials, which are 1 .6 ~r tr ~4k *et.

41 arranged in a tangential direction to the inner wall of the reactor. A slag tap 220 is provided at the lower portion of the reactor, and a slag cooling tank 221 is provided beneath the slag tap. 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 burners forms a whirl flow along the inner wall of the reactor and descends downward because of the existence of a central constriction 230 located at the middle of the reactor, and turns to a stream upward at the slag tap portion. Accordingly, a retention time of the coal and the oxidizing agent can be ensured, and the gasification reaction proceeds. Similarly, the natural gas and the steam supplied into the reactor through the upper stage burners forms a whirl flow along the inner i wall of the reactor and descends downward because of the re existence of the constriction 222 located at the outlet portion of the reactor, and turns to a straight stream upward at the central constriction 230.

20 Next, function of the present embodiment is explained hereinafter. The coal 10 and the oxidizing "agent such as oxygen 11 are supplied into the reactor from the lower stage burners 211, which are provided at the coal gasification chamber 231, and the natural gas 20 and the steam 22 are supplied into the reactor from the upper stage burners 212, which are provided at the natural gas reforming chamber 232. Under the above situation, if the 42 size of the reactor is intended to decrease, a sufficient distance between the lower stage burners 211 and the upper stage burners 212 for contacting the coal 10 and the oxygen 11 with the natural gas 20 and the steam 22 after the coal 10 and the oxygen 11 react sufficiently each other, can not be obtained. Therefore, in accordance with the present embodiment, the central constriction 230 was provided at the middle of the reactor, the coal gasification chamber 231, wherein the coal gasification reaction proceeded mainly, was composed at the lower portion of the reactor, and the natural gas reforming chamber 232, wherein the natural gas reforming reaction proceeded mainly, was composed at the upper portion of the reactor.

A mass ratio of oxygen/coal, which are supplied from the lower stage burners, was selected to be higher than a case when only coal was supplied for the gasification, in order to ensure a sufficient amount of heat for reforming the natural gas supplied from the upper stage burners. The reactor shown in the present embodiment can also utilize the heat energy generated by the coal .gasification reaction at the lower stage reaction zone o 223 for the steam reforming reaction of the natural gas proceeding in the upper stage reaction zone 224 without rrer using any heat exchanger, as well as the method shown in the embodiment 3.

The functions of the slag tap 220 provided at the 43 lower portion of the reactor, the slag cooling tank 221 provided beneath the slag tap, and the constriction 222 provided at the outlet portion of the reactor are as same as the functions shown in the embodiment 3.

(Embodiment FIG. 10 illustrates schematically an embodiment of a methyl alcohol producing apparatus, using natural gas and coal as raw materials, of the present invention. The methyl alcohol producing apparatus comprises a coal gasification reactor 280, a dust removal apparatus 240, a desufurization apparatus 250, a natural gas reforming apparatus 260, and a methyl alcohol synthesizing apparatus 310, which are arranged in the order cited 'Iti S 5

CC,

above.

Raw materials are supplied to the cola gasification reactor from a coal sur.ply section and an oxygen supply section. The coal supply section comprises a hopper 110 and a coal supply control valve 111. The coal supply 20 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 atmosphere inside the hopper with nitrogen 12 which is a by-product from an oxygen producing apparatus 130. The coal supply control valve 111 is a valve to control a supplying amount of the raw coal depending on the 44 operating condition of the system.

The coal gasification reactor 280 comprises lower stage burners 211 and upper stage burners for supplying the coal 10, and an oxidizing agent such as oxygen 11, and steam 22, the heat recovery portion 213 for cooling 15 the reacted gas, and a slag tap 221 for collecting slag o0|€ I t which is generated by fusing ashes component of the coal.

L 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 20 the coal gasification reactor lower than 900 9C, which is a necessary temperature for proceeding the steam reforming reaction of the natural gas in the natural gas reforming apparatus 260, which is installed in the downstream of the reactor. Practically, a cyclone, or a 44 It C 25 ceramic filter can be utilized.

The desUlfurizing apparatus 250 uses a dry process as same as the dust removal apparatus, in order not to il rrrC- decrease the temperature of the gas. The dry process is a method for fixing H 2 S gas directly by fine powder of calcium carbonate or zinc oxide.

The methyl alcohol producing division 300 is as the same as the conventional one.

Next, function of the present embodiment is explained hereinafter. The steam reforming reaction of the natural gas 20 requires a high temperature as 1600 C if no catalyst is used. In accordance with the method shown 4 in the embodiment 1, the 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 the coal. In accordance with the present embodiment, a catalyst is used in the natural gas reforming apparatus, the reforming reaction of the natural gas proceeds at S~ about 900 0 C. Accordingly, if a temperature about 1000 C can be obtained by the coal gasification apparatus, it is sufficient 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 25 becomes possible. Furthermore, although the coal and the natural gas are not reacted in the same reactor as the embodiment 1, use of a heat exchanger can be unnecessary 46 by arranging the coal gasification reactor 280 and the natural gas reforming apparatus 260 in a series, and effective utilization of heat as same as the embodiment .i, r

I

Il It t

II

I Si

I

1 is possible.

In accordance with the present embodiment, a 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 an absolute value is realized as same as the embodiment 1.

In the embodiments 1-4, a slurry of coal and water can be used as a raw material for producing the H 2 -CO mixed gas instead of coal, and a combination of the coal-water slurry, natural gas, steam, and an oxidizing agent such 15 as oxygen can be used as the raw material for producing the H 2 -CO mixed gas. Using the coal-water slurry instead of coal facilitates the handling of the raw materials.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A method for producing hydrogen (Hz)-carbon monoxide (CO) mixed gas comprising the steps of: pulverising coal, and supplying pulverised coal into a first zone of a reactor with an oxidizing agent for generating hydrogen and carbon monoxide, wherein 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 Ead pulverized coal and said oxidizing agent, and discharging generated H 2 -CO mixed gas from the reactor, wherein a generating ratio of Hydrogen to carbon monoxide is controlled to a specified value within the range of 0.5 to 3 by adjusting supplying amounts of said coal and said natural gas into the reactor.

2. A method for producing H 2 -CO mixed gas as claimed in claim 1, wherein 20 said first zone in the reactor is maintained at a temperature in a range of 900 1600 0 C, and said second zone in the reactor is maintained at a temperature in a range of 800 900 0 C with catalyst, or of 1000 1600°C without catalyst.

3. A method for producing H 2 -CO mixed gas as claimed in claim 1, wherein said second zone is designated in a downstream region of gas flow from said first zone in the reactor.

4. A method for producing H 2 -CO mixed gas 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 swirl flow along a circumferential direction in the reactor, respectively.

Q:\OPER\MJC\62066-96.SPE 11 /98 -48- A method for producing H 2 -CO mixed gas 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 hydrogen (H 2 )-carbon monoxide (CO) mixed gas comprising: a raw materials supplying equipment comprising a pulveriser, storage tanks for respective of coal, oxygen, natural gas, and water a steam generator, and control valves for regulating the supplying amounts of respective of coal, oxygen, natural gas, and steam, a reactor comprising a first zone, which comprises f: at least one inlet respectively for supplying each of pulverized coal and oxygen, a second zone, which comprises at least one inlet respectively for supplying each 1of natural gas and steam, and an outlet for discharging the generated H 2 -CO mixed gas, a heat recovery device, a desulfurization equipment, and a dust removal equipment, wherein the generating ratio of hydrogen to carbon monoxide in the generated H 2 -CO mixed gas is controlled to a specified value within the range of 0.5 to 3 by regulating the supplying amount of coal and natural gas, respectively, by said control valves.

7. An apparatus for producing H 2 -CO mixed gas as claimed in claim 6, wherein said second zone is provided in a downstream region of gas flow from said first zone in the reactor.

8. An apparatus for producing H 2 -CO mixed gas as claimed in Q:\OPE\MJC\6 064-96.SPE 113/98 -49- claim 6, wherein said first zone is provided with a means for generating a swirl flow of the supplied pulverised coal, and oxygen streams, respectively, in a direction along the inner circumference of the circular wall of the reactor and said second zone is provided with a means for generating a swirl flow of the supplied natural gas, and steam streams, respectively, in a direction along the inner circumference of the circular wall of the reactor.

9. An apparatus for producing H 2 -CO mixed gas as claimed in claim 9, wherein said means for generating a swirl flow in the first zone are blow-out burners for supplying pulverized coal, and oxygen streams, respectively, in a direction along the inner circumference of the circular wall of the reactor to generate a swirl flow of a mixture of the pulverized coal and the C: oxygen in the reactor, and Ssaid means for generating a swirl flow in the second zone are blow-out burners for supplying natural gas, and steam St, streams, respectively, in a direction along the inner circumference of the circular wall of the reactor to generate S- a swirl flow of a mixture of the natural gas and the steam in the reactor.

S 510. An apparatus for producing H 2 -CO mixed gas as claimed in claim 6, wherein a partition having at least a constriction is provided to the boundary of said first zone and said second zone in the reactor.

11. An apparatus for producing H 2 -CO mixed gas as claimed in claim 6, further comprising: plurality of burners are provided at side walls of the reactor in plural rows along the stream of generated gas, wherein Q:\OPER\MJC\62064-96,SPE -113/98 I I t I r 1h Lt 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 down stream region are composed so that supply of the coal with the oxidizing agent, and the natural gas with the steam can be changeable, and the rest of the burners are composed so 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 generating ratio of hydrogen to carbon monoxide in the generated H 2 -CO mixed gas is controlled by regulating the supplying amount of coal and natural gas, respectively, in a case when both the coal and the natural gas are supplied to the reactor.

12. An apparatus for producing H 2 -CO mixed gas as claimed in claim 6, further comprising: 20 plurality of burners are 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 25 burners in downstream regions, and the coal and the oxidizing agent are supplied from said burners in down stream region and said burners in upstream region, and an amount of oxygen supplied into the reactor more than 1 in an oxygen/coal ratio by weight is divided into two portions, the one portion exceeding 1 in the oxygen/coal ratio by weight is supplied though said oxygen supplying nozzles, and the other portion equal to 1 in the oxygen/coal ratio by weight is supplied through said burners in upstream region so as to prevent the lower portion of the reactor from local overheating. i I' i: i 1 I 1 i ii rcic 1 Irr~ tr Ir r r ritr Irri cirr t, iI I, r it El~ ii (I L Bi. I O ~I "4 Q:\oPSR\MJC\6206.96.S' -I I 19% -51

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

14. An apparatus for synthesizing methyl alcohol comprising: a methyl alcohol synthesizing apparatus for synthesizing methyl alcohol from H 2 -CO mixed gas generated by the apparatus for producing H 2 -CO mixed gas as claimed in claims 6-11, which is installed in a rear stage of said apparatus for producing H 2 -CO mixed gas.

15. An apparatus for producing methyl alcohol as claimed in claim 14, wherein: means for removing hydrogen sulfide in the generated H 2 CO mixed gas is provided at a stage prior to introducing the H 2 -CO mixed gas generated by the apparatus for producing H 2 -CO 20'mixed gas into said methyl alcohol synthesizing apparatus.

16. A method for producing methyl alcohol from coal, natural gas, steam, and oxidizing agent, wherein a natural gas reforming equipment is installed in a 25 downstream region of a coal gasification equipment, which produces hydrogen-carbon monoxide in accordance with a method according to any one of claims 1 to

17. An integrated energy system, wherein a production of methyl alcohol and electric power generation are performed concurrently by installing an apparatus for synthesizing methyl alcohol from H 2 -CO mixed gas, and an electric power generator using H 2 -CO mixed gas as fuel, 7 at a rear stage from the apparatus for producing said H2- p Q:\OPER\MC\62064-96.SPE 11/3/98 -52- CO mixed gas as claimed in claim 6.

18. An integrated energy system as claimed in claim 17, wherein means for desulfurization is provided between the apparatus for producing said H 2 -CO mixed gas and either one of said apparatus for synthesizing methyl alcohol from said H 2 -CO mixed gas and said electric power generator using said H 2 -CO mixed gas as fuel.

19. A method for operating an integrated system, wherein a production of methyl alcohol and electric power generation are performed concurrently by installing an apparatus for synthesizing methyl alcohol from H 2 -CO mixed gas, and an electric power generator using H 2 -CO mixed gas as fuel, at a rear stage from the apparatus for producing said H 2 -CO mixed gas as claimed in claim 6, comprising the steps I 20 of: S:controlling supplying amounts of raw materials comprising coal, natural gas, steam, and an oxidizing agent to said I apparatus for producing H 2 -CO mixed gas so as to make the <composition of the generated gas have a ratio of H,/CO of 2, and supplying said H,-CO mixed gas to said apparatus for synthesizing methyl alcohol from H 2 -CO mixed gas, when only production of methyl alcohol is performed, controlling supplying amounts of raw materials comprising coal, steam, and an oxidising agent to said apparatus for producing H 2 -CO mixed gas by proceeding only a coal gasification, and supplying said H 2 -CO mixed gas to said electric power generator using H 2 -CO mixed gas as fuel, when only electric power generation is performed, and, controlling supplying amounts of coal and natural gas to Q:\OPER\MJC\62064-96.SPE -11/3/98 -53 said apparatus for producing H 2 -CO mixed gas, and distributing amount of the H 2 -CO mixed gas generated by said apparatus for producing H 2 -CO mixed gas to said apparatus for synthesizing methyl alcohol from H 2 -CO mixed gas and said electric power generator using H 2 -CO mixed gas as fuel, based on a ratio of methyl alcohol production and electric power generation so as to make a load to said apparatus for synthesizing methyl alcohol from H 2 -CO mixed gas stable with corresponding to a variation of electric power demand, when both the methyl alcohol production and the electric power generation are performed. i

20. Method for producing H2-CO mixed gas and/or for producing methyl alcohol substantially as hereinbefore described with reference to any one of the embodiments illustrated in the i accompanying drawings.

21. Apparatus for producing H 2 -CO mixed gas and/or for producing methyl alcohol substantially as hereinbefore described with reference to any one of the embodiments illustrated in the accompanying drawings. 11

22. H 2 -CO mixed gas when produced by the method or apparatus I" claimed in any one of the preceding claims. S23. Methyl alcohol when produced by the method or apparatus T claimed in any one of the preceding claims. DATED this 11th day of March, 1998 Hitachi, Ltd. by DAVIES COLLISON CAVE Patent Attorneys for the Applicant Abstract of the Disclosure Object of the present invention is to provide a method and an apparatus for producing methyl alcohol with a high efficiency and a low cost. In producing H 2 -CO mixed gas, which 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 ratios of natural gas/coal, oxygen/coal, and steam/natural gas are controlled to generate the H 2 -CO mixed gas having a composition, wherein a ratio of H 2 /CO is equal to 2, which is suitable for synthesizing methyl alcohol, and methyl alcohol is synthesized from the H2-CO mixed gas. In producing the 15 H 2 -CO mixed gas, coal and the oxidizing ?gent are reacted to generate CO, CO 2 H 2 0, H 2 and heat, and the generated Iy heat is utilized to react natural gas and steam for t. {generating the H 2 -CO mixed gas. i. In comparison with conventional methods for "r 20 producing methyl alcohol from natural gas, and by coal gasification, a conversion ratio from the raw material "c to methyl alcohol can be improved by 10 15 in an absolute value.