CN117089372A - Preparation method of coal gas for shaft furnace direct reduction - Google Patents
Preparation method of coal gas for shaft furnace direct reduction Download PDFInfo
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- CN117089372A CN117089372A CN202311269675.1A CN202311269675A CN117089372A CN 117089372 A CN117089372 A CN 117089372A CN 202311269675 A CN202311269675 A CN 202311269675A CN 117089372 A CN117089372 A CN 117089372A
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- gas
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- molten iron
- dust removal
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- 239000003034 coal gas Substances 0.000 title claims abstract description 76
- 230000009467 reduction Effects 0.000 title claims abstract description 32
- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 239000007789 gas Substances 0.000 claims abstract description 251
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 112
- 229910052742 iron Inorganic materials 0.000 claims abstract description 55
- 239000003245 coal Substances 0.000 claims abstract description 49
- 239000002893 slag Substances 0.000 claims abstract description 46
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 26
- 239000001301 oxygen Substances 0.000 claims abstract description 26
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 24
- 238000001816 cooling Methods 0.000 claims abstract description 20
- 239000007921 spray Substances 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 18
- 238000010438 heat treatment Methods 0.000 claims abstract description 9
- 229910000805 Pig iron Inorganic materials 0.000 claims abstract description 8
- 238000002844 melting Methods 0.000 claims abstract description 6
- 230000008018 melting Effects 0.000 claims abstract description 6
- 238000005507 spraying Methods 0.000 claims abstract description 5
- 230000006698 induction Effects 0.000 claims abstract description 4
- 239000000428 dust Substances 0.000 claims description 68
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 38
- 238000002407 reforming Methods 0.000 claims description 28
- 239000003345 natural gas Substances 0.000 claims description 20
- 238000004519 manufacturing process Methods 0.000 claims description 10
- 230000005484 gravity Effects 0.000 claims description 9
- 230000000630 rising effect Effects 0.000 claims description 9
- 239000000498 cooling water Substances 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 7
- 238000007791 dehumidification Methods 0.000 claims description 6
- 238000004062 sedimentation Methods 0.000 claims description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 abstract description 11
- 229910052717 sulfur Inorganic materials 0.000 abstract description 11
- 239000011593 sulfur Substances 0.000 abstract description 11
- 230000008569 process Effects 0.000 abstract description 9
- 239000002817 coal dust Substances 0.000 abstract description 5
- 230000003009 desulfurizing effect Effects 0.000 abstract description 2
- 230000001174 ascending effect Effects 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- 229910002091 carbon monoxide Inorganic materials 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 238000006477 desulfuration reaction Methods 0.000 description 3
- 230000023556 desulfurization Effects 0.000 description 3
- 238000002309 gasification Methods 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000003749 cleanliness Effects 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000006057 reforming reaction Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/46—Gasification of granular or pulverulent flues in suspension
- C10J3/48—Apparatus; Plants
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/72—Other features
- C10J3/82—Gas withdrawal means
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/72—Other features
- C10J3/82—Gas withdrawal means
- C10J3/84—Gas withdrawal means with means for removing dust or tar from the gas
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J2300/00—Details of gasification processes
- C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
- C10J2300/0913—Carbonaceous raw material
- C10J2300/093—Coal
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]
Abstract
The invention discloses a preparation method of coal gas for direct reduction of a shaft furnace, belongs to the technical field of direct reduction of a coal gas shaft furnace, and solves the problems of long process flow, high sulfur removal cost, high difficulty in heating coal gas and the like caused by cooling, desulfurizing and heating the coal gas prepared by the coal gas in the prior art. The preparation method comprises the steps of sequentially connecting an intermediate frequency furnace and a gas making furnace, wherein the gas making furnace is arranged above the intermediate frequency furnace; filling pig iron into an intermediate frequency furnace, melting the pig iron into molten iron through induction heating, and forming a molten iron pool in the intermediate frequency furnace; pulverized coal, slag former and O 2 Spraying molten iron into a molten iron pool through an oxygen coal spray gun; s in the pulverized coal reacts with a slag former on the surface of a molten iron bath, S is fixed in molten iron and slag, O 2 And coal dust react on the surface of the molten iron bath to generate coal gas, ash in the coal dust reacts with a slag former on the surface of the molten iron bath to generate coal gasSlag is formed, and gas is generated. The invention can be used for coal gas of a shaft furnace.
Description
Technical Field
The invention belongs to the technical field of direct reduction of a coal gas shaft furnace, and particularly relates to a preparation method of coal gas for direct reduction of the shaft furnace.
Background
Existing coal-to-gas technologies typically include Texaco coal gasification technology, shell coal gasification technology, lurgi gasification technology, etc., which typically convert pulverized coal to carbon monoxide and hydrogen by steam or oxygen in the pulverized coal.
The carbon monoxide and the hydrogen prepared by the method can contain more impurities (such as sulfides), a desulfurization device is additionally arranged to purify the cooled coal gas, and the desulfurized coal gas is required to be reheated when the cooled coal gas is subsequently used for direct reduction of the gas-based shaft furnace.
However, the difficulty of heating the coal gas is high, so that the whole process flow of the coal gas is complex, and the cost is high.
Disclosure of Invention
In view of the analysis, the invention aims to provide a preparation method of coal gas for direct reduction of a shaft furnace, which solves the problems of long process flow, high sulfur removal cost, high difficulty in heating the coal gas and the like caused by cooling, desulfurizing and heating the coal gas prepared from the coal gas in the prior art.
The aim of the invention is mainly achieved by the following technical scheme.
The invention provides a preparation method of coal gas for direct reduction of a shaft furnace, which comprises the following steps:
step 1: the intermediate frequency furnace and the gas making furnace are connected in sequence, and the gas making furnace is arranged above the intermediate frequency furnace;
step 2: filling pig iron into an intermediate frequency furnace, melting the pig iron into molten iron through induction heating, and forming a molten iron pool in the intermediate frequency furnace;
step 3: pulverized coal, slag former and O 2 Spraying molten iron into a molten iron pool through an oxygen coal spray gun;
step 4: s in the pulverized coal reacts with a slag former on the surface of a molten iron bath, S is fixed in molten iron and slag, O 2 And the ash in the pulverized coal reacts with a slag former on the surface of the molten iron bath to generate slag, so that the coal gas is generated.
Further, the step 4 further comprises the following steps:
step 5: and (3) carrying out post-treatment on the coal gas prepared in the step (4).
Further, the post-treatment includes dust removal and reforming performed sequentially.
Further, the dust removal includes the steps of:
step a: introducing the gas prepared in the step 4 into a gas rising pipe, wherein part of dust in the gas falls on the side wall of the gas rising pipe under the action of gravity and moves downwards to return to a gas making furnace, so that primary dust removal is completed;
step b: introducing the gas subjected to primary dust removal into the bottom of the first settling chamber through a gas descending pipe, then, enabling the gas subjected to primary dust removal to move upwards along the space between the gas descending pipe and the inner wall of the first settling chamber, and enabling part of dust in the gas to fall to the bottom of the first settling chamber under the action of gravity so as to finish secondary dust removal;
step c: and enabling the gas subjected to secondary dust removal to enter the second sedimentation chamber from the side surface of the second sedimentation chamber, and performing cyclone dust removal to finish tertiary dust removal.
Further, the reforming comprises the steps of:
respectively introducing the dedusted coal gas and natural gas into a coal gas reformer;
in the gas reforming furnace, the dedusted gas reacts with natural gas to react CO in the dedusted gas 2 Converted to CO.
Further, the step 5 further comprises the following steps:
step 6: the gas after post-treatment is divided into two parts, wherein one part is directly connected into the shaft furnace to be used as reducing gas, and the other part is connected into a daily gas user pipeline.
Further, in the step 6, the other part of the gas is introduced into the daily gas user pipeline, and the method further comprises the following steps:
and cooling, dehumidifying and dedusting the other part of the gas in sequence.
Further, a venturi is adopted for cooling, a dehydrator is adopted for dehumidification, and a filter is adopted for dust removal.
Further, the cooling, dehumidifying and dedusting of the other part of the coal gas sequentially comprises the following steps:
step 61: the other part of the coal gas is fed into a venturi tube, cooling water is introduced into the venturi tube, and the coal gas is subjected to wet cooling by adopting the cooling water to obtain cooled coal gas;
step 62: the cooled coal gas is dehydrated in sequence through a dehydrator and is dedusted through a filter.
Further, the preparation method adopts a coal gas system; the coal gas making system comprises an intermediate frequency furnace and a gas making furnace, a molten iron molten pool is arranged in the intermediate frequency furnace, the gas making furnace comprises a gas making furnace body and an oxygen coal spray gun, and a gas outlet of the oxygen coal spray gun is positioned in the gas making furnace body and faces the molten iron molten pool.
Compared with the prior art, the invention can realize at least one of the following beneficial effects.
A) The invention provides a method for preparing coal gas for shaft furnace direct reduction, which adopts O 2 The process combined with coal dust injection gas making and molten iron bath slag making can obtain coal gas with lower sulfur content through on-line desulfurization while coal gas making. Specifically, the gas making furnace is arranged above the intermediate frequency furnaceA molten iron pool O is arranged in the frequency furnace 2 And the pulverized coal is sprayed into a molten iron bath, sulfur in the pulverized coal is absorbed by molten iron and slag, and sulfur in the pulverized coal is solidified in the molten iron and slag, so that high-temperature coal gas with lower sulfur content can be obtained.
B) The method for preparing the coal gas for the direct reduction of the shaft furnace provided by the invention has the advantages that the ash content (for example, siO 2 And Al 2 O 3 ) The slag former is sprayed into a molten iron bath through an oxygen coal spray gun 5, ash content reacts with the slag former to generate slag with lower melting point, and the slag floats on the surface of the molten iron in a liquid state, so that the slag is conveniently discharged from the intermediate frequency furnace 1.
In the invention, the technical schemes can be mutually combined to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the embodiments of the invention particularly pointed out in the written description and drawings.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, like reference numerals being used to refer to like parts throughout the several views.
FIG. 1 is a flow chart of a method for producing gas for direct reduction of a shaft furnace according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a coal gas system used in a method for preparing coal gas for direct reduction of a shaft furnace according to an embodiment of the present invention;
fig. 3 is a diagram of a natural gas nozzle in a coal gas system according to an embodiment of the present invention.
Reference numerals:
1-an intermediate frequency furnace; 2-a iron adding port; 3-gas making furnace; 4-slag hole; 5-oxygen coal spray gun; 6-oxygen top lance; 7-a gas rising pipe; 8-a manhole; 9-a gas down pipe; 10-a first settling chamber; 11-a second settling chamber; 12-reforming a furnace body; 13-a three-way pipeline; 14-a gas outlet for the shaft furnace; 15-a gas connecting pipe; a 16-venturi; 17-dehydrator; 18-a filter; 19-a blow-off valve; 20-a water outlet; 21-a sewage outlet; 22-natural gas nozzles; 23-connecting flanges; 24-air duct.
Detailed Description
The following detailed description of preferred embodiments of the invention is made in connection with the accompanying drawings, which form a part hereof, and together with the description of the embodiments of the invention, are used to explain the principles of the invention and are not intended to limit the scope of the invention.
Example 1
The embodiment provides a method for preparing coal gas for direct reduction of a shaft furnace, referring to fig. 1 to 2, comprising the following steps:
step 1: the intermediate frequency furnace 1 and the gas making furnace 3 are connected in sequence, and the gas making furnace 3 is arranged above the intermediate frequency furnace 1;
step 2: pig iron is filled into the intermediate frequency furnace 1, melted into molten iron through induction heating, and a molten iron pool is formed in the intermediate frequency furnace 1;
step 3: pulverized coal, slag former and O 2 Spraying molten iron into a molten iron pool through an oxygen coal spray gun 5;
step 4: s in the pulverized coal reacts with a slag former on the surface of a molten iron bath, S is fixed in molten iron and slag, O 2 And the ash in the pulverized coal reacts with a slag former on the surface of the molten iron bath to generate slag with lower melting point, so as to generate high-quality coal gas with lower sulfur content.
Pulverized coal and O ejected from the oxygen-coal lance 5 2 The following reaction with molten iron in the intermediate frequency furnace 1 occurs:
2C+O 2 (g)＝2CO(g)
C+O 2 (g)＝CO 2 (g)
3Fe+C＝Fe 3 C
2Fe 3 C+O 2 ＝6Fe+2CO(g)
compared with the prior artCompared with the technology, the preparation method of the coal gas for the direct reduction of the shaft furnace provided by the embodiment adopts O 2 The process combined with coal dust injection gas making and molten iron bath slag making can obtain coal gas with lower sulfur content through on-line desulfurization while coal gas making. Specifically, the gas making furnace 3 is arranged above the intermediate frequency furnace 1, a molten iron pool, O, is arranged in the intermediate frequency furnace 1 2 And the pulverized coal is sprayed into a molten iron bath, sulfur in the pulverized coal is absorbed by molten iron and slag, and sulfur in the pulverized coal is solidified in the molten iron and slag, so that high-temperature coal gas with lower sulfur content can be obtained.
At the same time, due to ash content (e.g., siO 2 And Al 2 O 3 ) The slag former is sprayed into a molten iron bath through an oxygen coal spray gun 5, ash content reacts with the slag former to generate slag with lower melting point, and the slag floats on the surface of the molten iron in a liquid state, so that the slag is conveniently discharged from the intermediate frequency furnace 1.
In order to perform post-treatment such as dust removal and dehumidification on the produced gas, the preparation method further comprises the following steps after the step 4:
step 5: the gas produced in step 4 is subjected to a post-treatment, which illustratively includes dust removal and reforming in sequence.
Wherein, the dust removal specifically comprises the following steps:
step a: introducing the gas prepared in the step 4 into a gas ascending pipe 7 and a gas descending pipe 9 which are connected in sequence, wherein part of dust in the gas falls on the side wall of the gas ascending pipe 7 under the action of gravity in the gas ascending pipe 7 and moves downwards to return to the gas making furnace 3, so that primary dust removal is completed;
step b: introducing the gas subjected to primary dust removal into the bottom of the first settling chamber 10 through a gas descending pipe 9, then enabling the gas subjected to primary dust removal to move upwards along the space between the gas descending pipe 9 and the inner wall of the first settling chamber 10, and enabling part of dust in the gas to fall to the bottom of the first settling chamber 10 under the action of gravity so as to finish secondary dust removal;
step c: the gas after secondary dust removal enters the second sedimentation chamber 11 from the side surface of the second sedimentation chamber 11 to carry out cyclone dust removal, and the tertiary dust removal is completed.
Here, it is emphasized that in the coal gas system of the present embodiment, before being fed into the shaft furnace, both the tank (for example, the reforming furnace body 12, the first settling chamber 10 and the second settling chamber 11) and the pipeline (for example, the gas rising pipe 7 and the gas falling pipe 9) are adopted for the gas dust removal and the reforming, the dust removal is achieved by utilizing the gravity of the dust itself and the change of the movement state, the gas is not required to be cooled, the effective dust removal can be achieved on the basis that the temperature is not required, and the gas after the dust removal and the reforming can be directly used for the shaft furnace.
The reforming specifically comprises the following steps:
respectively introducing the dedusted coal gas and natural gas into a coal gas reformer;
in the gas reforming furnace, the dedusted gas reacts with natural gas to react CO in the dedusted gas 2 Converted to CO.
This is because, in the gas making furnace 3, pulverized coal and O 2 Oxidation reaction occurs, and CO is inevitably generated in the whole process 2 CO in high-temperature gas through the arrangement of a gas reformer 2 With CH in natural gas 4 The reaction can produce CO and H 2 (CO 2 +CH 4 ＝2CO+2H 2 ) Reducing CO in hot gas 2 The content of the gas is increased, and the reduction potential of the gas is improved, so that the gas can be reformed and regulated by the gas reformer, and the reformed gas does not need to be cooled, desulfurized and heated, and can be directly used for direct reduction of the shaft furnace.
Here, it is emphasized that in the coal gas system of the present embodiment, before being fed into the shaft furnace, both the tank (for example, the reforming furnace body 12, the first settling chamber 10 and the second settling chamber 11) and the pipeline (for example, the gas rising pipe 7 and the gas falling pipe 9) are adopted for the gas dust removal and the reforming, the dust removal is achieved by utilizing the gravity of the dust itself and the change of the movement state, the gas is not required to be cooled, the effective dust removal can be achieved on the basis that the temperature is not required, and the gas after the dust removal and the reforming can be directly used for the shaft furnace.
It should be noted that, the following steps may be further included after the step 5:
step 6: the gas after post-treatment is divided into two parts, wherein one part is directly connected into the shaft furnace to be used as reduction gas, and the other part is connected into a daily gas user pipeline to be used for daily gas consumption of gas users.
In practical application, for daily gas consumption of a gas user, the requirement on the cleanliness of the gas is generally high, and the high-temperature gas needs to be cooled, so in the step 6, after the gas after post-treatment is divided into two parts, the following steps are further included before the gas after post-treatment is introduced into a pipeline of the daily gas user:
the gas after post-treatment is sequentially cooled, dehumidified and dedusted, wherein a venturi tube 16 is adopted for cooling, a dehydrator 17 is adopted for dehumidification, and a filter 18 is adopted for dedusting.
Correspondingly, the method for sequentially cooling, dehumidifying and dedusting the coal gas after the post-treatment comprises the following steps of:
step 61: the gas after the post-treatment is fed into a venturi tube 16, cooling water is introduced into the venturi tube 16, and the high-temperature gas is subjected to wet cooling by adopting the cooling water to obtain cooled gas;
step 62: the cooled gas is dehydrated by a dehydrator 17 (e.g., centrifugal dehydrator 17) in turn, and is dedusted by a filter 18.
The method for preparing the gas for direct reduction of the shaft furnace adopts a coal gas system with the following structure, as shown in fig. 2, and comprises an intermediate frequency furnace 1 and a gas making furnace 3 which are sequentially connected, wherein the gas making furnace 3 is arranged above the intermediate frequency furnace 1, the top end of the intermediate frequency furnace 1 is provided with an opening, the bottom end of the gas making furnace 3 is provided with an opening, the opening is connected with the opening to realize that the gas making furnace 3 is communicated with the top end of the intermediate frequency furnace 1, a molten iron molten pool is arranged in the intermediate frequency furnace 1, the gas making furnace 3 comprises a gas making furnace body and an oxygen coal spray gun 5, the gas outlet of the oxygen coal spray gun 5 is positioned in the gas making furnace and faces the molten iron molten pool, and the oxygen coal spray gun 5 is used for spraying mixed powder of coal dust and a slag former and O 2 To iron (Fe)A water bath.
The oxygen-coal spray gun 5 may be a sleeve-type oxygen-coal spray gun, the pulverized coal and the slag former are sprayed into a molten iron bath from a central spray hole of the oxygen-coal spray gun 5, the oxygen is sprayed into the molten iron bath from a circumferential seam of the oxygen-coal spray gun 5, and the pulverized coal is wrapped by the oxygen for combustion, so that the combustion efficiency of the pulverized coal and the oxygen is improved, and the coal gas with high CO content is generated.
It is to be understood that, in order to load pig iron into the intermediate frequency furnace 1, a tap hole 2 is formed in the furnace body of the intermediate frequency furnace 1, and the tap hole 2 is located at the top end of the intermediate frequency furnace 1 and at the junction of the intermediate frequency furnace 1 and the gas making furnace 3.
Similarly, in order to facilitate the discharge of the slag, the furnace body of the gas making furnace 3 is provided with a slag hole 4, and the slag hole 4 is positioned at the bottom end of the gas making furnace 3, so that the slag hole 4 is close to the bottom end of the gas making furnace 3, and is beneficial to regularly discharging the slag. Considering that slag is usually discharged by taking the slag to a certain height, the distance between the center line of the slag hole 4 and the bottom end of the gas making furnace 3 is 5-10 cm, for example.
In order to supplement oxygen to the intermediate frequency furnace 1 and improve the reaction rate of C, the gas making furnace 3 further comprises an oxygen top lance 6, wherein the oxygen top lance 6 is arranged in the gas making furnace 3 and is connected with the top of the gas making furnace 3 through a lifting assembly. In this way, in the process of preparing the gas by the coal, the oxygen top lance 6 is lowered to the lower part of the gas making furnace 3 by the lifting component, the oxygen top lance 6 can intensively supply oxygen to the central area of the molten iron pool, and the oxygen top lance reacts with C in the molten iron to generate the gas, so that the reaction rate of C and the gas preparing efficiency of the coal are improved.
In order to perform post-treatment such as dust removal and dehumidification on the produced coal gas, the coal gas system further comprises a post-treatment utilization unit, wherein the post-treatment unit comprises a dust removal assembly, a coal gas reformer and a three-way pipeline 13 which are sequentially connected, and an air inlet of the dust removal assembly is connected with an air outlet of the gas making furnace 3.
The gas reformer comprises a reforming furnace body 12 and a plurality of natural gas nozzles 22 which are uniformly arranged, referring to fig. 3, the natural gas nozzles 22 are communicated with the inner cavity of the reforming furnace body 12, a three-way pipeline 13 is provided with a three-way air inlet, a gas outlet for users and a gas outlet 14 for shaft furnaces, the air outlet of the reforming furnace body 12 is connected with the three-way air inlet, the gas outlet for users is connected with gas users, daily gas for the gas users can be used, the gas outlet 14 for shaft furnaces is directly connected with the shaft furnaces, and the gas can be directly used for the direct reduction of the shaft furnaces without cooling the gas.
This is because, in the gas making furnace 3, pulverized coal and O 2 Oxidation reaction occurs, and CO is inevitably generated in the whole process 2 CO in high-temperature gas through the arrangement of a gas reformer 2 With CH in natural gas 4 The reaction can produce CO and H 2 (CO 2 +CH 4 ＝2CO+2H 2 ) Reducing CO in hot gas 2 The content of the gas is increased, and the reduction potential of the gas is improved, so that the gas can be reformed and regulated by the gas reformer, and the reformed gas does not need to be cooled, desulfurized and heated, and can be directly used for direct reduction of the shaft furnace.
Illustratively, along the gas flow direction, the reforming furnace body 12 comprises an expanding section, a constant diameter section and a reducing section which are sequentially connected, so that the gas enters the reforming furnace body 12 from the expanding section, the gas and the natural gas are convenient to uniformly mix, the reforming reaction is facilitated, the constant diameter section provides enough reaction space for the gas to react with the natural gas, the necking section can improve the flow velocity of the reformed gas, and the gas is convenient to be discharged out of the gas reforming furnace; the natural gas nozzle 22 is positioned at the expanding section of the lower part of the reforming furnace body 12, the distance between the natural gas nozzle 22 and the bottom of the reforming furnace body 12 is 15-20 cm, the included angle between the gas outlet angle of the natural gas nozzle 22 and the tangential direction of the reforming furnace body 12 is 15-50 degrees, and natural gas enters the reforming furnace body 12 in a rotational flow manner, so that the natural gas is convenient to be uniformly mixed with gas, the flow path of the natural gas and the gas can be prolonged, and the reaction time is prolonged.
In practical application, for the daily gas consumption of gas user, the requirement on the cleanliness of gas is higher generally, and need to cool down to high temperature gas, therefore, above-mentioned coal gas system still includes cooling unit, dehumidification unit and the dust removal unit that connects gradually, and the air inlet of cooling unit passes through gas connecting pipe 15 and is connected with user gas outlet, and the gas outlet of dust removal unit is connected with gas user.
Illustratively, the cooling unit is selected as a venturi 16, the dehumidifying unit is selected as a dehydrator 17, a drain 21 and a drain outlet 20 are provided at the bottom of the dehydrator 17, and the dust removing unit is selected as a filter 18. Correspondingly, the specific process of cooling, dehumidifying and dedusting the high-temperature coal gas discharged by the user through the gas outlet is as follows:
the high-temperature gas is discharged from a gas outlet for users, is supplied into a venturi tube 16 through a gas connecting pipe 15, cooling water is introduced into the venturi tube 16, and the high-temperature gas is subjected to wet cooling by adopting the cooling water to obtain cooled gas; the cooled gas is dehydrated in turn by a dehydrator 17 (for example, a centrifugal dehydrator 17), and is dedusted by a filter 18, thereby completing the purification of the high-temperature gas. The venturi tube 16 has the dual functions of hot gas cooling and gas purifying, the dehydrator 17 is used for reducing moisture in the gas, the filter 18 is used for dedusting, and the high-temperature gas is cooled and purified and then is output to a gas user for use.
In order to improve the gas safety of the gas user, the gas system further comprises a gas release valve 19, and the filter 18 is connected with the gas user through the gas release valve 19, that is, the gas outlet of the filter 18 is connected with the gas inlet of the gas release valve 19, and the gas outlet of the gas release valve 19 is connected with the gas inlet of the gas user. This is because the bleed valve 19 itself has an auto-ignition function, and when an emergency occurs, it can ignite and bleed the gas, thereby ensuring the operation safety of the gas system.
To the structure of dust removal subassembly, specifically, it includes the dust removal pipeline that connects gradually, first settling chamber 10 and second settling chamber 11, is connected through high temperature resistant pipeline between first settling chamber 10 and the second settling chamber 11, and the air inlet of dust removal pipeline is connected with the gas outlet of gas making stove 3, and the gas outlet of second settling chamber 11 passes through flange 23 and is connected with the air inlet of gas reforming stove, and like this, gas can carry out secondary dust removal through first settling chamber, can carry out tertiary dust removal through the second settling chamber.
In order to achieve the dust removing function of the dust removing pipe, the dust removing pipe includes a gas rising pipe 7 and a gas falling pipe 9 connected in sequence along a gas flow direction, the gas rising pipe 7 is inclined upward, the gas falling pipe 9 is inclined downward, and the gas falling pipe 9 extends to a lower portion of the first settling chamber 10, for example. On the one hand, after the coal gas flowing out of the gas making furnace 3 enters the coal gas ascending pipe 7, dust with larger particles in the coal gas can fall on the side wall of the coal gas ascending pipe 7 under the action of gravity and move downwards to return to the gas making furnace 3 and finally fall into the intermediate frequency furnace 1, so that the coal gas can be dedusted once; on the other hand, the gas downcomer 9 is arranged to facilitate the gas transport.
In order to facilitate the overhaul of the gas ascending pipe 7 and the gas descending pipe 9, the joint of the two is provided with an overhaul hole 8, and the overhaul hole 8 can be opened to overhaul or clean the gas ascending pipe 7 and the gas descending pipe 9.
For the structure of the second settling chamber 11, specifically, the cyclone separation structure comprises a cyclone cone and an air duct 24, wherein a cyclone inlet is formed in the side face of the cyclone cone, the air outlet direction of the cyclone inlet is inclined relative to the radial direction of the cyclone cone, the cyclone inlet is connected with the air outlet of the first settling chamber 10, the bottom end of the cyclone cone is closed, the air duct 24 is arranged in the cyclone cone and is coaxially arranged with the cyclone cone, an airflow loop is arranged between the bottom end of the air duct 24 and the cyclone cone, and the top end of the air duct 24 is in sealing connection with the cyclone cone. Thus, the coal gas enters the cyclone cone from the cyclone inlet and flows downwards along the cyclone cone to the bottom end of the cyclone cone; because the bottom end of the cyclone cone is closed, the gas can only flow into the air duct 24 through an airflow loop, and moves upwards along the air duct 24 and flows out of the second settling chamber 11, and dust in the gas can be deposited at the bottom of the cyclone cone.
Illustratively, the air duct 24 is a high-temperature alloy air duct 24, that is, the material of the air duct 24 is a high-temperature alloy, the thickness of the high-temperature alloy air duct 24 is 20-40 mm, and the heat-resistant temperature is greater than or equal to 1150 ℃.
The first settling chamber 10 and the second settling chamber 11 are arranged in series, the middle is connected through a high temperature resistant pipeline, the gas descending pipe 9 extends to the lower part of the first settling chamber 10, the flow speed is greatly reduced after the gas passes through the gas ascending pipe 7 and the gas descending pipe 9, the dust correspondingly loses power, a part of dust with larger particles can be deposited at the bottom of the first settling chamber 10, the air flow upwards flows into the high temperature resistant pipeline along the space between the gas descending pipe 9 and the inner wall of the first settling chamber 10, and enters the second settling chamber 11 from the side surface (namely a cyclone inlet) of the second settling chamber 11 through the high temperature resistant pipeline, the gas downwards flows to the bottom of the second settling chamber 11 along the cyclone inner wall of the second settling chamber 11, the dust falls into the bottom of the second settling chamber 11, the gas flows upwards along the central line direction of the air guide drum 24 through the air flow loop after flowing to the bottom of the second settling chamber 11, and further enters the gas reforming furnace, dust is conveniently cleaned at the bottom of the first settling chamber 10 and the second settling chamber 11, and dust is discharged.
The first settling chamber 10 and the second settling chamber 11 can remove more than 90% of dust in the hot coal gas, so as to meet the use requirement of the shaft furnace.
The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention.
Claims (10)
1. The preparation method of the gas for the direct reduction of the shaft furnace is characterized by comprising the following steps:
step 1: the intermediate frequency furnace and the gas making furnace are connected in sequence, and the gas making furnace is arranged above the intermediate frequency furnace;
step 2: filling pig iron into an intermediate frequency furnace, melting the pig iron into molten iron through induction heating, and forming a molten iron pool in the intermediate frequency furnace;
step 3: pulverized coal, slag former and O 2 Spraying molten iron into a molten iron pool through an oxygen coal spray gun;
step 4: s in the pulverized coal reacts with a slag former on the surface of a molten iron bath, S is fixed in molten iron and slag, O 2 And the ash in the pulverized coal reacts with a slag former on the surface of the molten iron bath to generate slag, so that coal gas is generated.
2. The method for producing a gas for direct reduction of a shaft furnace according to claim 1, characterized in that the step 4 is followed by the steps of:
step 5: and (3) carrying out post-treatment on the coal gas prepared in the step (4).
3. The method for producing a gas for direct reduction of a shaft furnace according to claim 2, wherein the post-treatment comprises dust removal and reforming performed sequentially.
4. A method for producing a gas for direct reduction of a shaft furnace according to claim 3, characterized in that the dust removal comprises the steps of:
step a: introducing the gas prepared in the step 4 into a gas rising pipe, wherein part of dust in the gas falls on the side wall of the gas rising pipe under the action of gravity and moves downwards to return to a gas making furnace, so that primary dust removal is completed;
step b: introducing the gas subjected to primary dust removal into the bottom of the first settling chamber through a gas descending pipe, then, enabling the gas subjected to primary dust removal to move upwards along the space between the gas descending pipe and the inner wall of the first settling chamber, and enabling part of dust in the gas to fall to the bottom of the first settling chamber under the action of gravity so as to finish secondary dust removal;
step c: and enabling the gas subjected to secondary dust removal to enter the second sedimentation chamber from the side surface of the second sedimentation chamber, and performing cyclone dust removal to finish tertiary dust removal.
5. A method for producing a gas for direct reduction of a shaft furnace according to claim 3, characterized in that the reforming comprises the steps of:
respectively introducing the dedusted coal gas and natural gas into a coal gas reformer;
in the gas reforming furnace, the dedusted gas reacts with natural gas to react CO in the dedusted gas 2 Converted to CO.
6. The method for producing a gas for direct reduction of a shaft furnace according to claim 2, characterized in that said step 5 is followed by the further step of:
step 6: the gas after post-treatment is divided into two parts, wherein one part is directly connected into the shaft furnace to be used as reducing gas, and the other part is connected into a daily gas user pipeline.
7. The method for preparing gas for direct reduction of shaft furnace according to claim 6, wherein in the step 6, the other part of the gas is introduced into a daily gas user pipeline, and further comprising the steps of:
and cooling, dehumidifying and dedusting the other part of the coal gas in sequence.
8. The method for producing a gas for direct reduction of a shaft furnace according to claim 7, wherein the cooling is performed by a venturi, the dehumidification is performed by a dehydrator, and the dust removal is performed by a filter.
9. The method for producing a gas for direct reduction of a shaft furnace according to claim 8, wherein the cooling, dehumidifying and dedusting of another part of the gas in this order comprises the steps of:
step 61: the other part of the coal gas is fed into a venturi tube, cooling water is introduced into the venturi tube, and the coal gas is subjected to wet cooling by adopting the cooling water to obtain cooled coal gas;
step 62: the cooled coal gas is dehydrated in sequence through a dehydrator and is dedusted through a filter.
10. The method for producing a gas for direct reduction of a shaft furnace according to any one of claims 1 to 9, characterized in that the production method employs a coal gas system;
the coal gas making system comprises an intermediate frequency furnace and a gas making furnace, wherein a molten iron molten pool is arranged in the intermediate frequency furnace, the gas making furnace comprises a gas making furnace body and an oxygen coal spray gun, and a gas outlet of the oxygen coal spray gun is positioned in the gas making furnace body and faces the molten iron molten pool.
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