JP5169662B2 - Caking filler for coke production with excellent grindability and its production method - Google Patents

Description

  The present invention relates to a caking additive for coke production having excellent grindability and a method for producing the same.

  In blast furnace operation, high-strength coke is required as a reducing material in order to ensure air permeability in the furnace and maintain stable operation. In order to produce high-strength coke, high-quality strong caking coal is required as coking coal. Many methods for producing high-strength coke using non-caking coal or non-caking coal as raw coal have been proposed (see Patent Documents 1 to 3).

  As a method of producing coke using low-quality coal as raw coal, conventional low-quality coal is pulverized and dried, classified into pulverized coal and coarse coal, and kneaded by adding a caking additive to pulverized coal. In addition, there is known a method of blending pulverized coal and pulverized coal that have been granulated or pseudo-particulated into particles or pseudo-particles into coarse coal and charging them into a coke oven (see Patent Documents 4 to 7). ).

  By adding a caking agent to pulverized coal and making it into particles or pseudo-particles, while suppressing dust generation during coal transportation, it supplements the low caking properties of low quality coal when dry coal blending, Coke strength can be improved. A caking agent may be added to the coarse coal along with the pulverized coal from the viewpoint of improving the caking property of the low quality coal and improving the coke strength.

  Conventionally, coal-based binders (tar, pitch, etc.), petroleum-based binders and the like have been used as binders for improving the caking properties of low-quality coal (Patent Document 8). To 11 and Non-Patent Document 1, for example).

  Coke ovens not only improve coke strength, but also generate dust during coal transportation and charging into the coke oven, generation of adhering carbon on the coke oven wall, and coke extrusion load, depending on the type and amount of binder. As a result, the properties of the caking additive added to the blended coal for the purpose of improving coke strength, working environment, and stabilizing the operation of the coke oven, and the setting conditions for the amount added have been studied. It has been.

In order to stably produce high-strength (DI ¹⁵⁰ ₁₅ , 84.5 or more) coke by effectively utilizing petroleum-based heavy residues (residues obtained by removing light components from crude oil). And the manufacturing method of the high intensity | strength coke which adds a petroleum-type heavy residue to a coal blend as a caking additive was proposed (refer patent documents 12-15).

  Petroleum heavy residue is a caking filler with a large allowance for improving coke strength, but it has a softening point of 70 ° C or higher and is in a solid state at room temperature, but the temperature immediately softens during pulverization with a pulverizer. There is a problem that the grindability is poor, that is, it is softened by rising above the point, adheres to the grinder, and the working efficiency of the grinder decreases (see Patent Document 16).

  So far, from the viewpoint of improving the properties of coal and increasing the coke strength, a technology for improving the properties of coal using heavy oil has been proposed (see Patent Document 17). There is a limit to improving the coke strength equal to or greater than that of petroleum heavy residues. On the other hand, no attempt has been made to improve the properties of petroleum heavy residues from the viewpoint of improving grindability.

  In order to use inexpensive low-quality coal and improve blast furnace productivity and stabilize blast furnace operation, further improvement in coke strength is required, as well as efficient coal pretreatment and coke operation. Therefore, the role excellent in the grindability of the caking filler is important. Therefore, when using petroleum heavy residues as a caking additive, there is a need to improve the grindability of petroleum heavy residues that have a high margin for improving coke strength.

JP 2003-226879 A JP 2006-283008 A JP 2007-002052 A JP-A-10-183136 Japanese Patent Laid-Open No. 11-116970 JP 2001-072982 A JP 2003-226879 A JP-A 48-074011 JP 59-179586 A JP 09-241653 A JP 2006-291190 A JP 2006-291190 A JP 2007-009016 A JP 2007-009030 A JP 2007-321076 A JP-A-10-076170 Japanese Patent Application Laid-Open No. 07-233380 Coal chemistry and industry (Sankyo Publishing Co., Ltd., 1977 edition, p.315)

  The present invention recognizes that the role of petroleum heavy residues is important as a caking filler material with high coke strength improvement in terms of improving coke strength. The objective is to improve the efficiency of coal pretreatment and coke oven operation. An object of the present invention is to provide a petroleum heavy residue-based caking filler capable of solving the above-described problems and a method for producing the same.

  The present inventors diligently studied a method for improving the pulverization property of petroleum heavy residues used as a caking filler. As a result, it was found that a caking filler with excellent grindability can be produced by adding and mixing pulverized coal to molten petroleum heavy residue.

  This invention was made | formed based on the said knowledge, and the summary is as follows.

(1) In a method for producing a caking additive for coke production comprising a petroleum heavy fraction and pulverized coal,
(A) Add pulverized coal having a particle size of 90% or more to 3 mm or less to the melted petroleum heavy fraction, then mix,
(B) A method for producing a coking filler for coke production, which is excellent in grindability, characterized by cooling at a cooling rate of 20 ° C./min or higher to a temperature below the softening point of the petroleum heavy fraction.

  (2) The method for producing a caking additive for coke production as described in (1) above, wherein the heavy petroleum fraction is solvent deasphalted asphalt.

  (3) The method for producing a caking additive for coke production having excellent grindability according to the above (1) or (2), wherein the softening point of the petroleum heavy fraction is 70 ° C. or higher. .

  (4) The grindability according to any one of (1) to (3) above, wherein 10 to 200 parts by mass of pulverized coal is added to and mixed with 100 parts by mass of the petroleum heavy fraction. The production method of the caking filler for coke manufacture excellent in the.

  (5) Coke production excellent in grindability according to any one of (1) to (4) above, wherein after the cooling, the caking filler is pulverized to a particle size of 3% or less of 70% or more. Method for caking filler.

  (6) The caking for coke production excellent in grindability, which is produced by the method for producing a caking additive for coke production excellent in grindability according to any one of the above (1) to (5). Supplementary material.

  According to the present invention, pulverized coal can be used to modify a petroleum heavy residue having a high cost for improving coke strength, and a caking filler for coke production having excellent crushability can be produced. The coking strength can be improved by adding the caking filler to the low-quality coal and dry distillation, and the efficiency of the pretreatment of the raw coal and the operation of the coke oven can be greatly increased.

  The present invention will be described with reference to the drawings. In FIG. 1, the manufacturing process of the caking filler of the present invention (the present invention process, FIG. 1 (b)) is compared with the manufacturing process of the conventional caking filler (the conventional process, FIG. 1 (a)). Show.

  In the conventional process, the petroleum heavy fraction Z supplied in a molten state from the reactor 1 is cooled by the cooling device 2 to a temperature below the softening point of the petroleum heavy fraction Z, and then the crude heavy fraction Z It conveys to the grinding | pulverization apparatus 3, and coarsely grind | pulverizes, and caking filler Zb is obtained.

  As shown in FIG. 2, this caking filler Zb is transported and deposited on the deposited caking filler 6a in the raw material yard 5, and stored in the hopper 7a as appropriate. The coal supplied from the deposited coal 6 via the hopper 7 and the caking filler Zb supplied from the hopper 7a are mixed on the belt conveyor, pulverized by the pulverizer 8, and charged into the coke oven 9.

  Since the caking filler Zb is obtained by solidifying a petroleum heavy fraction generated by petroleum refining, it is originally poorly pulverizable, has a softening point of 70 ° C. or higher, and is in a solid state at room temperature. However, when the caking filler is pulverized, if the temperature of the caking filler rises due to the frictional heat generated, there is a problem that the caking filler softens easily and adheres to the pulverizer, making it more difficult to grind. It was.

  In the process of the present invention, the petroleum heavy fraction Z supplied in a molten state and the pulverized coal X having a particle size of 3 mm or less are mixed by the mixing device 4 from the reactor 1. After mixing, the mixture in a molten state is cooled at a cooling rate of 20 ° C./min or more to a temperature below the softening point of the petroleum heavy fraction Z with the cooling device 2, and then conveyed to the coarse pulverization device 3. And coarsely pulverized to obtain a caking filler material Za composed of a petroleum heavy fraction and pulverized coal.

  As shown in FIG. 2, the caking filler material Za is conveyed and deposited on the deposited caking filler material 6a in the raw material yard 5, and is stored in the hopper 7a as appropriate. The subsequent steps are the same as the conventional steps.

Thus, the manufacturing method of the caking filler for coke production of the present invention (the method of the present invention)
(A) Add pulverized coal having a particle size of 90% or more to 3 mm or less to the melted petroleum heavy fraction, then mix,
(B) It is characterized by cooling at a cooling rate of 20 ° C./min or more to a temperature below the softening point of the petroleum heavy fraction.

  The caking filler produced by the production method of the present invention (the caking filler of the present invention) is produced by adding and mixing pulverized coal having a particle size of 3% or less of 90% or more to a molten petroleum heavy fraction. Therefore, the pulverized coal is contained in a dispersed state in the petroleum heavy fraction, and the pulverized coal in the petroleum heavy fraction becomes the starting point of destruction when the caking filler is pulverized. Compared with the filler (petroleum heavy fraction), the grindability is remarkably increased.

  Moreover, since the caking filler of the present invention contains pulverized coal in the petroleum heavy fraction, it has a lower viscosity than the petroleum heavy fraction, and contains pulverized coal in a dispersed state. Even when heated, the viscosity remains low.

  For this reason, when crushing the caking filler of the present invention, even if the temperature of the caking filler rises due to frictional heat generated inside the crusher, the amount of adhesion to the crusher due to softening becomes extremely small, and crushing The decline in sex is suppressed.

  The effect of improving the pulverization property of the caking filler of the present invention is that the particle size of the pulverized coal added to the molten petroleum heavy fraction is 3 mm or less and 90% or more, and the pulverized coal is dispersed in the petroleum heavy fraction. It is demonstrated by making it contain in a state.

  When the particle size of the pulverized coal is coarser than the above particle size range, it becomes difficult for the pulverized coal to be present in a dispersed state in the heavy petroleum fraction, suppressing softening due to frictional heat during pulverization and reducing caking properties. It is impossible to obtain a sufficient effect of maintaining the above.

  The molten mixture obtained by adding pulverized coal with a particle size of 90% or more to 3 mm or less to the melted petroleum heavy fraction is cooled to a temperature below the softening point of the petroleum heavy fraction, cooling rate: 20 ° C./min or more. Cooled by.

  Due to this rapid cooling, non-uniform strain is accumulated in the solidified caking filler material, and this non-uniform strain is caused by a synergistic action with pulverized coal having a particle size of 90% or more of 3 mm or less existing in a dispersed state. The grindability of the is improved.

  When the particle size of the pulverized coal is coarser than the above particle size, it becomes difficult for the pulverized coal to be present in a dispersed state in the petroleum heavy fraction, and softening due to frictional heat during pulverization is suppressed and viscosity reduction is maintained. A sufficient effect cannot be obtained.

  If the cooling rate when cooling the molten mixture to a temperature below the softening point of the petroleum heavy fraction is slower than 20 ° C./min, it becomes difficult to introduce non-uniform strain into the solidified caking filler, The effect of improving the grindability of the caking filler due to non-uniform strain cannot be obtained sufficiently.

  As described above, the caking filler of the present invention contains pulverized coal in a dispersed state in the petroleum heavy fraction and accumulates non-uniform strain by the above (a) and (b). When the heavy system fraction is modified and the caking filler is pulverized, the amount of adhesion to the pulverizer can be remarkably reduced, and the grindability can be remarkably improved as compared with the petroleum heavy fraction.

  In addition, the petroleum heavy fraction has a high coke strength improvement allowance, and the pulverized coal added to improve the petroleum heavy fraction can use raw coal for coke production, The addition of pulverized coal does not reduce the coke improvement effect of petroleum heavy fractions.

  The brand and properties of the pulverized coal added to the petroleum heavy fraction are not particularly limited in order to express the effect of improving the grindability of the caking filler.

  The petroleum heavy fraction is not limited in terms of components and / or properties, but a petroleum heavy fraction having a softening point of 70 ° C. or higher is preferable because it is easy to handle. In particular, it is preferable to use solvent deasphalted asphalt generated in the petroleum refining process as the petroleum heavy fraction.

  Here, the solvent deasphalting asphalt is a residue obtained by subjecting asphalt to a solvent desulfurizing treatment.

  Furthermore, according to the present invention, pulverized coal of 0.5 mm or less that causes dust generation, and further pulverized coal of 0.3 mm or less contained in the pulverized coal having a particle size of 90% or more of 3 mm or less Since it is confined in the filler, it suppresses the generation of dust when transporting to the coke oven and when charging the coke, reduces the amount of carbon adhering to the furnace wall due to dust generation when charging the coke oven, and An increase in coke extrusion load due to generation can be suppressed.

  The mixing ratio of the pulverized coal added to the petroleum heavy fraction is not particularly limited as long as the crushability of the caking filler can be secured.

  However, if the amount of pulverized coal is too much for the amount of heavy petroleum fractions, the viscosity of the molten mixture will drop sharply when mixed with molten heavy petroleum fractions, making handling difficult, In addition, if the amount of pulverized coal is too small relative to the amount of heavy petroleum-based fraction, naturally, the effect of improving the pulverization of the caking filler is not sufficiently exhibited.

  Therefore, in order to produce a caking filler excellent in grindability while maintaining good handling of the molten mixture, 10 to 200 parts by mass of pulverized coal is added to 100 parts by mass of petroleum heavy fraction. It is preferable to add and mix. When the amount of pulverized coal is less than 10 parts by mass with respect to 100 parts by mass of the petroleum heavy fraction, the effect of improving the pulverization of the caking filler is not sufficiently exhibited.

  In addition, when the amount of pulverized coal exceeds 200 parts by mass with respect to 100 parts by mass of the petroleum heavy fraction, the viscosity of the molten mixture is rapidly reduced, and handling becomes difficult.

  The caking filler of the present invention is pulverized after cooling and charged into a coke oven together with raw coal. The particle size after pulverization is not particularly limited, but from the viewpoint of achieving uniform mixing with the raw coal, it is preferable to pulverize the caking filler to a particle size of 3% or less and 70% or more.

  In the present invention, the pulverizability of the caking filler can be evaluated by the following method.

  In general, HGI (Hard Grove Index) measured by the method described in JIS M8801 is known as an index for evaluating coal pulverizability.

  However, the HGI (hard glove index) measured by this method is an index for coal, and is a method for evaluating the grindability of a caking filler having a much lower softening point than coal. Not suitable.

  In the present invention, as a method for evaluating the crushability of the caking filler, for example, the caking filler is treated at a rate of 200 kg / h using a small crusher (hammer crusher) having a crushing capacity of 50 to 500 kg / h. After crushing at a speed for 2 hours, the caking filler adhering to the inside of the crusher (hammer and casing) is collected, and the crushability of the caking filler is evaluated based on the measured amount of adhesion.

  The evaluation criteria for the crushability of the caking filler in this evaluation method are prepared in advance by preparing a plurality of coal samples in which moisture is adjusted to change the adhesion of the crusher, and a plurality of coals having different adhesion properties by the above method. The upper limit (0.5 kg) of the amount of deposit that pulverizes the sample and enables continuous operation of the pulverizer (corresponding to the amount of deposit when pulverizing a 15% moisture coal sample in the experiment) is evaluated for grindability The standard.

  That is, the evaluation of the crushability of the caking filler in the present invention, after crushing the caking filler material by the above method, when the adhesion amount inside the grinder is less than the adhesion amount of the crushability evaluation criteria, The pulverization property of the caking filler is considered to be good. When the adhesion amount exceeds the evaluation standard, the pulverizing property of the caking filler is evaluated to be poor.

  Next, examples of the present invention will be described. The conditions of the examples are one example of conditions adopted for confirming the feasibility and effects of the present invention, and the present invention is limited to this one example of conditions. Is not to be done. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

Example 1
As the petroleum heavy fraction, the residue (solvent deasphalted) after separation of the light oil by solvent extraction of the heavy petroleum fraction (asphalt) with the softening point shown in Table 1 is used to remove this solvent. Asphalt was heated to a temperature of about 250 ° C. and dissolved, pulverized coal was added, and after the caking filler was produced under the production conditions shown in Table 1, the grindability of the obtained caking filler was evaluated.

  The results are also shown in Table 1. In addition, the coal blend used the volatile matter amount (VM): 28% and total expansion coefficient (TD): 50%.

  The crushability of the caking filler was evaluated by crushing the caking filler at a processing rate of 200 kg / h for 2 hours using a small crusher (hammer crusher) having a crushing capacity of 50 to 500 kg / h. The caking filler material adhering to the inside of the pulverizer (hammer and casing) was collected, and the caking filler material was evaluated based on the measured value of the adhering amount.

  The evaluation criteria for the crushability of the caking filler material are prepared in advance by preparing a plurality of coal samples whose moisture is adjusted to change the adhesion of the crusher, and crushing a plurality of coal samples having different adhesion properties by the above method. The upper limit (0.5 kg) of the amount of adhesion that enables continuous operation of the pulverizer (corresponding to the amount of adhesion in the case of pulverizing a 15% moisture coal sample in the experiment) was used as an evaluation standard for pulverization.

  Evaluation of the crushability of the caking filler shown in Table 1 after crushing the caking filler by the above method, when the adhesion amount inside the pulverizer is less than the adhesion amount of the crushability evaluation criteria, The pulverizing property of the caking filler was determined to be good. When the adhesion amount exceeded the evaluation standard, the pulverizing property of the caking filler was evaluated to be poor.

  From Table 1, Invention Examples 1 to 5 implemented under conditions in which the particle size, cooling temperature, and cooling rate of the coal added to the caking filler are within the range specified in the present invention enable continuous operation of the pulverizer. It is below the upper limit (0.5 kg) of the adhesion amount, and the crushability of the caking filler is improved.

  On the other hand, Comparative Examples 1 to 4 carried out under conditions where the particle size, cooling temperature and cooling rate of the coal added to the caking filler deviate from the range defined in the present invention have an adhesion amount of 1.0 to 4.0. And the upper limit (0.5 kg) of the adhesion amount that enables continuous operation of the pulverizer, the caking property of the caking filler is inferior.

(Example 2)
The caking filler produced in Invention Example 1 and Invention Example 4 was pulverized to a particle size of -3 mm and 80%, and then pulverized to -3 mm and 80% (VM): 28%, total expansion coefficient (TD): 50 The coke was produced by adding 6% to the coal blend of 5% and dry-distilling in a coke oven. Note that the ratio of the total solvent degassed pitch to the blended coal is half, 3%.

The coke is produced by charging into a coke oven at a charging bulk density of 0.85 t / m ³ , subjecting the oven to a dry distillation time of 18.5 h under the condition of a furnace temperature of 1250 ° C., and a drum strength of the obtained coke. The index DI ¹⁵⁰ ₁₅ was measured.

As a comparative example, only the same blended coal (conditions in which no caking filler was added) was subjected to dry distillation in a coke oven under the same conditions, and coke strength was measured. As a result, the DI ¹⁵⁰ ₁₅ of coke was 85.0.

On the other hand, the DI ¹⁵⁰ ₁₅ of coke when the caking filler produced in Invention Example 1 is added is 86.0, and the coke when the caking filler produced in Invention Example 4 is added. DI was 86.2, and high strength coke could be produced in any case.

  As described above, according to the present invention, it is possible to produce a coking filler for coke production that is excellent in pulverization using pulverized coal. The efficiency can be greatly increased. Therefore, the present invention has great applicability in the coke manufacturing industry and the steel industry.

It is a figure which shows the process of manufacturing caking filling material. (A) shows a conventional process, and (b) shows a process of the present invention. It is a figure which shows the process of preparing raw coal and charging it into a coke oven.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reactor 2 Cooling device 3 Coarse crusher 4 Mixing device 5 Raw material yard 6 Deposited coal 6a Deposited caking filler 7, 7a Hopper 8 Crusher 9 Coke oven X Coal coal Z, Zb Caking filler (conventional)
Za caking filler (present invention)

Claims (6)

In the method of producing a caking filler for coke production comprising a petroleum heavy fraction and pulverized coal,
(A) Add and mix pulverized coal having a particle size of 3% or less of 90% or more to the melted petroleum heavy fraction,
(B) A method for producing a coking filler for coke production, which is excellent in grindability, characterized by cooling at a cooling rate of 20 ° C./min or higher to a temperature below the softening point of the petroleum heavy fraction.   The method for producing a caking additive for coke production with excellent grindability according to claim 1, wherein the petroleum heavy fraction is solvent-desulfurized asphalt.   The method for producing a caking filler for coke production having excellent grindability according to claim 1 or 2, wherein the softening point of the petroleum heavy fraction is 70 ° C or higher.   The coke excellent in grindability according to any one of claims 1 to 3, wherein 10 to 200 parts by mass of pulverized coal are added to and mixed with 100 parts by mass of the petroleum heavy fraction. A method for producing a caking filler for production.   The caking additive for coke production having excellent grindability according to any one of claims 1 to 4, wherein after the cooling, the caking filler is pulverized to a particle size of 70% or more of 3 mm or less. A method of manufacturing the material.   A caking additive for coke production excellent in grindability, produced by the method for producing a caking additive for coke production excellent in grindability according to any one of claims 1 to 5.

Images