JPH05116902A - Method for enriching hydrogen of combustible gas - Google Patents

Abstract

PURPOSE:To obtain an H2-enriched combustible gas by blowing gaseous hydrocarbons and O2 in the amt. sufficient to convert the hydrocarbons into H2 and CO into a melting and gasifying furnace and simultaneously blowing steam into the furnace to specify the gas temp. at the furnace outlet. CONSTITUTION:Reduced iron is charged into a melting and gasifying furnace 1 from a duct 9, and coal and coke are added from a feed port 5. O2 is blown in from a gas blowing port 11 to partially oxidize the generated gas, hence a combustible gas consisting essentially of CO and H2 is obtained, and the reduced iron is melted and reduced. The gaseous hydrocarbons, e.g. natural gas, shown by the formula CmHn (n/m=2.5) is introduced from a duct 12 and O2 is introduced from a duct 13 in the amt. sufficient to convert the gas into H2 and CO. Steam is introduced from a duct 14 to control the gas temp. to 900-1100 deg.C at the furnace outlet. The H2-enriched combustible gas is blown into a prereducing furnace 3 through a cyclone 2 to reduce the iron ore from a feed port 20, then discharged from a duct 21 and used as a crude raw gas for methanol synthesis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method capable of simultaneously producing pig iron and a raw material for synthesizing methanol, and more particularly to a hydrogen enrichment method for combustible gas generated from a melting gasifier used in the molten pig iron method.

[0002]

2. Description of the Related Art Up to now, an industrial method for simultaneously producing a raw material for synthesizing methanol at the same time as the production of pig iron has not been established.

Most of the production of pig iron depends on the blast furnace method, but as is well known, the blast furnace method requires high-quality coking coal and iron ore. As an alternative method, the molten iron making method has been attracting attention. As is well known, in the molten ironmaking method, coal is added to a melting gasifier, and this is partially combusted with oxygen to generate a combustible gas containing carbon monoxide and hydrogen as main components. Is a method for producing molten pig iron and reducing iron ore with a combustible gas generated in the gasification furnace to produce the reduced iron.

The molten ironmaking method can use low-quality iron ore,
Moreover, this is an epoch-making ironmaking method that does not require the coke production and iron ore sintering that are required in the blast furnace method, but the flammable gas generated during ironmaking becomes enormous and its effective use is It affects the economy. For this reason, inconveniences have arisen such as restrictions on the use of steam coal having a large amount of volatile matter, as well as restrictions on the setting of operating conditions such as the amount of coal supplied.

On the other hand, from the viewpoint of suppressing the generation of carbon dioxide, which is the cause of global warming, the removal of carbon dioxide and the appearance of clean energy with a low carbon content have become social needs.

As is well known, the components of the raw material gas for synthesizing methanol are hydrogen, carbon monoxide and carbon dioxide gas, and the composition thereof must satisfy the condition of H ₂ / (3CO ₂ + 2CO) = 1. That is, it is necessary to increase the hydrogen content in the raw material gas, but the gas generated in pig iron has a low hydrogen content because the source is coal. In order to use a gas with a low hydrogen content as a raw material gas for methanol,
A so-called CO shift reaction operation for converting CO into H ₂ is required, and the smaller the hydrogen content, the larger the amount of conversion, and accordingly the less the amount of methanol obtained.

In a complex plant for producing a methanol synthesis raw material from a combustible gas generated in molten pig iron, the flammable gas generated in the molten pig iron interferes with the operation of the pig iron production from the viewpoint of increasing the amount of methanol synthesis raw material to be obtained. It is a good idea to generate as much hydrogen-enriched combustible gas as possible within a range that does not cause it.

From the above object, as a conventional means for enriching hydrogen, as shown in JP-A-58-171510, steam is blown for the purpose of controlling the temperature of the melting gasification furnace,
As a result, it is introduced that hydrogen can be enriched. However, when steam is blown into the melting gasifier,
Water formation reaction of carbon _{(C + H 2 O = H} 2 + CO), reforming reaction of hydrocarbons _{{Cm Hn + mH 2 O =} (m + n / 2) H 2 +
Hydrogen can be enriched with mCO}, etc., but hydrogen enrichment due to these can only be expected at reaction temperatures of 900 ° C or higher, preferably 1000 ° C or higher, and both reactions are endothermic reactions, so flammability due to steam injection At present, there is a limit to the hydrogen enrichment of gas and many cannot expect it.

Further, if pig iron and a methanol synthesis raw material are to be produced at the same time, it is necessary to make the production amount of the pig iron constant and increase the production amount of the methanol synthesis raw material, or to secure the flexibility of the entire plant. That is, in response to a request to increase or decrease the production amount of the methanol synthesis raw material, it is necessary to be able to adjust the amount of gas generated in the melting gasifier without hindering the operation of molten pig iron. In the conventional method, it is conceivable to increase the amount of coal input to the melting gasifier and increase the amount of oxygen and steam injected accordingly. However, as described above, there is a limit to the hydrogen enrichment of the gas generated from the dissolution gasification furnace by injecting water vapor, so the combustible gas obtained by this method has a high carbon monoxide content, and this gas is used as the methanol synthesis raw material. In order to do so, it is necessary to take a CO shift reaction operation and take measures against load fluctuations in the entire methanol production system.

[0010]

DISCLOSURE OF THE INVENTION An object of the present invention is to meet the social needs of improving the economical efficiency of pig iron production and suppressing carbon dioxide emission by producing a methanol synthesis raw material from a combustible gas generated in the molten pig iron production operation. In order to make it possible, the flammable gas generated in the molten pig iron operation is a hydrogen-enriched gas suitable for methanol synthesis without disturbing the molten pig iron operation,
In addition, it is to provide a method capable of adjusting the generation amount.

[0011]

According to the present invention, coals are added to a melting gasifier, and the coals are partially combusted and gasified with oxygen to generate a combustible gas containing carbon monoxide and hydrogen as main components. Along with this, reduced iron is added to the melting gasifier to produce molten pig iron, and iron ore is reduced with a part or all of the combustible gas generated in the melting gasifier and added to the melting gasifier. A method comprising a combination of a molten pig iron operation for producing the reduced iron and an operation of using at least a part of a flammable gas generated in the molten pig iron operation as a raw material gas for methanol synthesis, wherein the dissolved gas A gaseous hydrocarbon having a chemical molecular formula of Cm Hn (n / m ≧ 2.5) and oxygen sufficient to convert the hydrocarbon into hydrogen and carbon monoxide are blown into the gasification furnace and the melting gasification furnace The temperature of flammable gas at the outlet is 900 It is a method for enriching hydrogen in a combustible gas generated in a melting gasifier for simultaneously producing pig iron and a raw material for synthesizing methanol, which is characterized in that steam is blown so as to be adjusted to a range of 1100 ° C.

The term "coal" as used in the present invention means not only coal but also coke, and reduced iron is not only completely perfected but also partially reduced iron ore. It is used in the meaning including.

That is, a feature of the present invention is that a coal and oxygen necessary for performing molten ironmaking are charged into a melting gasifier, and a gaseous hydrocarbon compound such as natural gas containing a large amount of hydrogen component and the compound. Is blown with oxygen sufficient to convert it into hydrogen and carbon monoxide, most of the compound is converted into hydrogen and carbon monoxide, and steam is added so that the gas temperature at the outlet of the melting gasifier is 900 ° C to 1100 ° C. It is to blow hydrogen gas to convert hydrogen components contained in water vapor into hydrogen, and to enrich the combustible gas generated in the melting gasifier with hydrogen.

[0014]

[Function] As is well known, in order to stably perform the molten ironmaking operation, the temperature in the melting gasification furnace must be maintained at the temperature necessary for the smelting reduction, and the melting gasification furnace needs the temperature for the smelting reduction. It is necessary that a large amount of carbon is always retained, and that the combustible gas generated in the melting gasifier has the reduction potential necessary for reducing iron ore.

According to the present invention, while maintaining the melting gasification furnace in such a state, the flammable gas generated in the melting gasification furnace can be enriched with hydrogen and the amount of the flammable gas generated can be adjusted. Is what you are trying to do.

As described above, while the reduced iron is charged into the melting gasification furnace at a constant rate, a controlled amount of coal and oxygen for melting and reducing the reduced iron is charged to stabilize the molten pig iron manufacturing operation. Gasified hydrocarbon compounds such as natural gas whose molecular formula can be expressed in the gasification furnace as Cm Hn and whose hydrogen component / carbon component ratio (n / m value) is 2.5 or more Then, by blowing an amount of oxygen {m / 2 mol of oxygen to 1 mol of Cm Hn} sufficient to convert the hydrocarbon compound into hydrogen and carbon monoxide, most of the hydrocarbon compound undergoes the following reaction. It is converted to hydrogen and carbon monoxide as shown in the formula. Cm Hn + m / 2O ₂ = n / 2H ₂ + mCO For example, when the hydrocarbon compound is natural gas containing methane as a main component, the value of n / m is about 4, which is a flammable gas obtained by injecting natural gas. The molar ratio (H ₂ / CO ratio) between the hydrogen component of the volatile gas and carbon monoxide is about 2.

The flammable gas temperature of the melting gasification furnace is 9
At 00 ° C. or higher, preferably at 1000 ° C. or higher, the following reaction occurs due to the injection of steam, and the flammable gas can be enriched with hydrogen. Hydrolysis reaction of carbon C + H ₂ O = H ₂ + CO Reforming reaction of hydrocarbon Cm Hn + mH ₂ O = (m + n /
2) H ₂ + mCO

The blowing of the hydrocarbon compound and oxygen and the blowing of the steam under the above conditions do not hinder the operation of the hot metal in the melting gasifier. This is because the hydrocarbon compound blown into the dissolution gasification furnace is partially combusted into gas by the separately injected oxygen, and the steam has a generated gas temperature of the dissolution gasification furnace of 900 ° to 110 ° C.
Since the temperature is adjusted to 0 ° C. and blown in, the temperature in the melting gasifier and the reduction potential of the combustible gas can be maintained, and the carbon hydrogenation reaction in the gas phase of the melting gasifier is small. Therefore, it does not impair the possession of carbon necessary for smelting reduction.

Therefore, a hydrocarbon compound and a chemical equivalent amount of oxygen for converting the compound into hydrogen and carbon monoxide are blown, and the temperature of the combustible gas at the outlet of the melting gasifier is 900 ° C.
By injecting water vapor to ~ 1100 ° C, the flammable gas generated in the melting gasifier is enriched with hydrogen without hindering the operation of molten pig iron. The amount of generated gas can be adjusted freely.

Further, the hydrogen and carbon monoxide consumed for the reduction of the iron ore are almost equal in amount, and are generated in the dissolution gasification furnace except for steam and carbon dioxide in the flammable gas after the reduction of the iron ore. Needless to say, the combustible gas described above, that is, the combustible gas enriched with hydrogen, can be obtained and used as a crude raw material for methanol synthesis.

Further, the gas obtained by partial combustion of the hydrocarbon compound is hydrogen-enriched as described above. For example, when methane is used, the H ₂ / CO ratio is about 2, and the gas is injected by the hydrocarbon compound. It is not necessary to increase the amount of CO shift reaction.

[0022]

EXAMPLES The present invention will now be described in more detail based on the embodiment shown in FIG. FIG. 1 is a system diagram showing an embodiment of the present invention. In FIG. 1, 1 is a melting gasification furnace, 2 is a high temperature cyclone, 3 is a preliminary reduction furnace, and 4 is a cyclone for a preliminary reduction furnace.

In the melting gasification furnace 1, a molten metal phase a,
A molten slag phase b having a gas phase interface is formed on the molten slag phase b, and a coal charging port 5 is provided near the furnace top of the melting gasifier 1.
A lance 6 for injecting an oxygen-containing gas toward the molten slag phase b and a conduit 7 for taking out a combustible gas generated in the melting gasifier 1 are provided.

The furnace body in contact with the hot metal phase a of the melting gasifier 1 is provided with a hot metal and slag discharge port 8, and the furnace body in contact with the molten slag phase b is charged with reduced iron. The conduit 9, the conduit 10 for refluxing the solids mainly composed of the char collected by the high temperature cyclone 2 to the melting gasifier 1, and the stirring of the molten slag phase b and the coal and char floating in the slag phase b An oxygen-containing gas blowing port 11 for gasifying is provided.

In the upper furnace body of the molten slag phase b, a conduit 12 for injecting a gaseous hydrocarbon compound, an oxygen-containing gas injecting conduit 13 for partial combustion gasification of the hydrocarbon compound, and steam injection. A conduit 14 is provided.

A cyclone 4 is provided side by side with a preliminary reduction furnace 3 for producing reduced iron to be supplied to the dissolution gasification furnace 1.
The preliminary reduction furnace 3 cyclone 4 is connected by a conduit 15 and a conduit 16, and a conduit 17 for introducing the combustible gas generated in the dissolution gasification furnace 1 is provided in the lower portion of the preliminary reduction furnace 3, and the conduit 17 is connected to the conduit 17. Is a conduit 18 for extracting a part of the combustible gas generated in the melting gasification furnace 1 as necessary and a conduit for cold reducing gas injection for adjusting the temperature of the combustible gas injected into the preliminary reduction furnace 3 as necessary 19 are provided.

The iron ore is charged into the preliminary reduction furnace 3 through the iron ore supply port 20, and the flammable gas used after the reduction of the iron ore is extracted through the conduit 21.

The melting gasification furnace 1 is operated by adjusting the basicity and fluidity of the coal and slag from the coal charging port 5 according to the amount of powdered granular reduced iron supplied from the conduit 9. Slag agent (limestone, etc.) is added. The coal charged into the smelting gasifier 1 is partially carbonized in the gas phase portion of the smelting gasifier 1, and is suspended and stays in the molten slag phase b together with the powdered granular iron and the char refluxed from the conduit 10, Oxygen blown from the lance 6 and the oxygen-containing gas blowing port 11 is partially combusted into gas to reduce reduced iron by melting.
The hot metal produced in the slag phase b is stored in the hot metal phase a and is discharged together with the slag from the discharge port 8 at a predetermined interval.

The flammable gas generated in the melting gasification furnace is introduced into the high temperature cyclone 2 through the conduit 7, and after separating solids mainly composed of char accompanying the gas, the conduit 17
Is blown into the preliminary reduction furnace 3. The char separated by the high temperature cyclone 2 is returned from the conduit 10 to the slag phase b of the melting gasifier 1 and is gasified together with coal.

The preliminary reduction furnace 3 has a fluidized bed system,
The iron ore charged from the supply port 20 has the cyclone 4 and is circulated from the conduit 16 to the preliminary reduction furnace while being reduced by the combustible gas supplied from the conduit 17. Further, a part of the reduced iron ore is charged into the dissolution gasification furnace 1 through the conduit 9, and the amount of this charging is adjusted by adjusting the amount circulated from the conduit 16 to the preliminary reduction furnace 1.

The flammable gas after reducing the iron ore is in the conduit 2
1 is used as a raw material gas for methanol synthesis. That is, the flammable gas taken out from the conduit 21 is introduced into the methanol synthesis column through a cooling / washing operation, a desulfurization operation, a CO shift reaction operation, and a decarbonation gas operation, and methanol is synthesized, but it is dissolved gasification. When only coal is supplied as the fuel to the furnace 1, the hydrogen content in the combustible gas generated in the dissolution gasification furnace 1, and further in the gas taken out from the conduit 21 as the raw material gas for methanol synthesis, is small. Therefore, in order to satisfy the condition of H ₂ / (3CO ₂ + 2CO) = 1 which is the condition of the raw material for methanol synthesis, the CO shift reaction (CO + H ₂ O = H ₂ + C
As described above, it is necessary to increase the conversion amount of carbon monoxide to hydrogen by O ₂ ), and if it is attempted to increase the acquisition amount of methanol, the operation condition changing operation becomes tedious. ..

In the present invention, a gaseous hydrocarbon compound such as natural gas is blown from the conduit 12 and a chemical equivalent amount of oxygen sufficient to convert the compound into hydrogen and carbon monoxide is blown from the conduit 13. Most of the hydrocarbon compounds are converted to hydrogen and carbon monoxide. In particular, in a high-temperature atmosphere in which the gas phase temperature of the melting gasification furnace 1 is 900 ° C. or higher, this reaction instantaneously progresses, the combustible gas in the melting gasification furnace 1 can be enriched with hydrogen, and the amount injected The amount of flammable gas generated can be adjusted without affecting the operation of the molten pig iron by adjusting. Further, steam is blown from the conduit 14 so that the temperature of the combustible gas becomes 900 ° C to 1100 ° C. If the amount of flammable gas generated by this operation exceeds the amount required for pre-reduction, the conduit 1
The excess gas is extracted from No. 8 and used as a raw material gas for methanol synthesis.

The temperature of the flammable gas blown into the preliminary reduction furnace 3 is adjusted by blowing cold reducing gas through the conduit 19,
As the cold reducing gas, a part of the gas extracted from the conduit 18 may be cooled and circulated, or the purge gas in the methanol synthesis step or the combustible gas extracted from the conduit 21 may be decarbonated gas. Etc. can be used.

Example The analytical values of the iron ore, coal, oxygen-containing gas and hydrocarbon compound used are as follows. Iron ore: All iron 68.8, FeO 2.8, others
1.7 wt% stone charcoal: industrial analysis value fixed carbon 51.5, volatile matter 33.
5, ash content 12.6, intrinsic water content 2.4% by weight Elemental analysis value C 72.9, H ₂ 4.8, O ₂ 7.
8, N ₂ 1.5, S 0.4, Ash 12.6 wt% Oxygen-containing gas: Oxygen 98.0, Nitrogen 2.0, other 0.0 vol% Hydrocarbon compound: CH ₄ 94.0, C ₂ H ₆ 3.5,
Other 2.5%

Initially, the method of the present invention, ie, the operation of injecting a hydrocarbon compound, is carried out in a state where the operation is stable by not performing injection of a hydrocarbon compound but using only coal as a gasification fuel and performing a molten pig iron operation. I went. The operation results are shown in Table 1.

[Table 1]

As is clear from the examples, according to the method of the present invention, a hydrogen-enriched combustible gas can be obtained without impairing the operation of molten pig iron, and the amount of the combustible gas obtained is greatly increased. be able to.

[0037]

EFFECTS OF THE INVENTION According to the method of the present invention, a hydrogen-enriched gas, which is advantageous for methanol synthesis in a plant for simultaneously producing pig iron and a methanol synthesis raw material, can be used to produce methanol without disturbing the operation of molten pig iron. Accordingly, it can be supplied arbitrarily, and the flexibility of the entire plant can be significantly improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Kaneda 4-6-22 Kannon-cho, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries Ltd. Hiroshima Works

Claims (1)

[Claims] 1. A coal gas is added to a melting gasification furnace, and the coals are partially combusted and gasified with oxygen to generate a combustible gas containing carbon monoxide and hydrogen as main components, and the melting gasification furnace. To produce molten pig iron by adding reduced iron to, to produce the reduced iron to be added to the melting gasifier by reducing iron ore with a part or all of the combustible gas generated in the melting gasifier A method comprising a combination of a molten pig iron operation and an operation of using at least a part of flammable gas generated in the molten pig iron operation as a raw material gas for methanol synthesis, which is represented by a chemical molecular formula in the melting gasifier. Cm Hn
A gaseous hydrocarbon having (n / m ≧ 2.5) and oxygen sufficient to convert the hydrocarbon into hydrogen and carbon monoxide are blown, and the combustible gas temperature at the outlet of the melting gasifier is set to 900.
A method for enriching hydrogen in a combustible gas generated in a melting gasification furnace for simultaneously producing pig iron and a raw material for synthesizing methanol, wherein steam is blown so as to be adjusted to a range of ˜1100 ° C.