RU2792812C1 - Blend for the production of metallurgical coke - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: blend composition for production of metallurgical coke and its application. The blend includes: a mixture of coal concentrates in the amount of 60-98% by weight, petroleum coke with a mass fraction of volatile substances from 8 to 12% in the amount of 1-20% by weight and a petroleum sintering additive in the amount of 1-20% by weight. Moreover, petroleum coke is obtained by delayed coking of heavy oil residues, and petroleum sintering additive is obtained by deep vacuum distillation of the tar visbreaking and has a softening temperature according to the softening point determination by ring-and-ball procedure of at least 105°C and a mass fraction of volatile substances from 45 to 65%.

EFFECT: reduction of the ash content of coke, expansion of the range of plasticity of the coal blend, increasing the value of hot strength (CSR) and reduction of the reactivity (CRI) of the obtained coke.

2 cl, 6 tbl, 24 ex

Description

Technical field

The present invention relates to the composition of the charge for the production of metallurgical coke.

State of the art

From the patent of the Russian Federation No. 2663145, a charge is known containing:

70-90 wt. % coal grades KS, and/or KSN, and/or KO, and/or TS, and/or OS,

1-30 wt. % oil sintering additive, which is the residue of oil refining with the following characteristics:

ash content Ad - no more than 2.5%;

the yield of volatile Vdaf - no more than 90%;

sulfur content Sd - no more than 5%;

softening temperature according to KiSh - not less than 40°С.

The description of this patent says that the specified mixture can be used to produce metallurgical coke without mixing with other grades of coal.

According to the results shown in Table 6 of the said patent, the reactivity indices (CRI) and post-reaction strength (CSR) obtained from batches consisting of KO coals and a sintering additive (mixtures 2, 3, 4) and consisting of KS coals and a sintering additive (mixture 6 , 7, 8) of coke are within CRI 27.9-30.2 and CSR 52.4-64.0, while coke obtained from monocomponent charges, consisting of 100% KO coals (charge 1) is similar and 100% KS coals (charge 5) were CRI - 32.2 and 31.8 and CSR - 55.1 and 47.3.

In table 6, there is a tendency to reduce the reactivity (CRI) of the obtained coke with an increase in the content of sintering additives with a softening temperature of 115°C in the range of 5-20 wt. % added to coals KO or KS.

The effect of increasing the content of the sintering additive with a softening temperature of 115°C in the range of 5-20 wt. % on post-reaction strength (CSR) is non-linear, since with a slight increase in the content of the additive, the indicated indicator increases, but then begins to decrease. The authors of the patent attribute this effect to the overfatting of coal, which occurs for different coals at different contents of the sintering additive.

Characteristics of coke obtained with a sintering additive with a softening temperature not equal to 115°C are absent in the patent of the Russian Federation No. softening below 40°C is impractical due to the decrease in the effect of improving the plastic properties and the appearance of signs of coal caking, which makes it impossible to store it in a pile.

The disadvantage of this invention is that it does not investigate the effect of sintering additives on multicomponent coal charge, ie coal charge containing more than one coal.

In addition, when adding a sintering additive, it is necessary to limit its content for each selected coal in order to prevent overfatting of the coal, which leads to a decrease in the strength of the resulting coke.

Also, in the above invention, there is no technology for supplying components in a liquid state to the coal charge and, as a result, the impossibility of applying the invention on an industrial scale.

The closest analogue of the claimed invention is a charge for the production of metallurgical coke, disclosed in RF patent No. 2627425, consisting of:

40.0-98.0 wt. % coal mixture,

1.0-30.0 wt. % petroleum coke, which is characterized by an ash content Ad not more than 2.5%, a volatile matter Vdaf not more than 25%, a sulfur content Sd not more than 5%,

1.0-30.0 wt. % of oil residues, which are characterized by an ash content Ad of not more than 2.5%, a volatile matter Vdaf of not more than 90%, a sulfur content of Sd of not more than 5%, an Horn index (IR) of at least 10.

The disadvantage of this mixture is that, according to the results presented in the above patent in table 2, with an increase in the content of petroleum coke and oil residues in the mixture, a decrease in the hot strength value (CSR) and an increase in the reactivity (CRT) of the coke occurred.

From the article Kovalchik R.V., Tomash A.A. Theoretical assessment of the effect of hot strength of CSR coke on its specific consumption in blast-furnace smelting // Priazovsky State Technical University. 2008. No. 18-1 it is known that an increase in the hot strength of CSR coke by 1% reduces the degree of direct reduction of iron R _d by 0.24% and reduces the consumption of coke by 1.05 kg/t of pig iron or by 0.22%.

Thus, a decrease in hot strength (CSR) results in an increase in coke consumption.

The object of the present invention is to overcome the above disadvantages.

Disclosure of the essence of the invention

The technical result of the claimed invention is to reduce the ash content of coke, expand the range of plasticity of the coal charge, increase the value of hot strength (CSR) and reduce the reactivity (CRI) of the obtained coke.

To solve the above problem and achieve the technical result, a charge for the production of metallurgical coke is proposed, including, wt %: a mixture of coal concentrates 60-98, petroleum coke with a mass fraction of volatile substances from 8 to 12% 1-20, oil sintering additive 1-20, moreover, petroleum coke is obtained by delayed coking of heavy oil residues, and petroleum sintering additive is obtained by deep vacuum distillation of the tar visbreaking residue and has a softening temperature according to the KiSh method of at least 105 ° C and a mass fraction of volatile substances from 45% to 65%.

Also, to solve the above problem and achieve a technical result, it is proposed to use the above charge for the production of metallurgical coke.

The oil sintering aid disclosed in the present invention is obtained by deep vacuum distillation of the tar visbreaking residue, which allows the selection of fractions boiling up to 520-540 ° C, respectively, such an oil sintering aid includes only the highest boiling tar visbreaking residue fractions.

The softening temperature of an oil sintering additive according to the R&S method (ring and ball) is determined in accordance with GOST 11506-1973 PETROLEUM BITUMES. Method for determining the softening point by ring and ball.

Due to the synergistic effect from the interaction of the indicated petroleum sintering additive and petroleum coke with a low content of volatile substances (up to 12%), the ash content of the coke decreases, the plasticity range of the coal charge expands, the hot strength value (CSR) increases, and the reactivity (CRT) of the obtained coke decreases.

Implementation of the invention

To check the possibility of achieving the claimed technical result, experimental coking of charge variants for the production of metallurgical coke was carried out, including, wt %:

a mixture of coal concentrates 60-98, petroleum coke with a mass fraction of volatile substances from 8 to 12% 1-20, petroleum sintering additive 1-20, moreover, petroleum coke is obtained by delayed coking of heavy oil residues, and petroleum sintering additive is obtained by deep vacuum distillation tar visbreaking residue and has a softening point according to the KiSh method of at least 105°C and a mass fraction of volatile substances from 45% to 65%.

To achieve satisfactory performance, the softening temperature of the oil sintering additive should be at least 105°C. volatile substances from 45% to 65%.

Were formed the following compositions of the coal charge (options No. 1-8), indicated in Tables 1, 2 and compared the quality of the obtained experimental coke with the quality of the coke from the base charge.

Within the framework of the experiment, in charge variants Nos. 1-8, petroleum coke and petroleum sintering additive with the following quality characteristics were used:

Petroleum coke - mass fraction of volatile substances 12.0%, mass fraction of sulfur 3.92%, ash content 0.20%;

Oil sintering additive - mass fraction of volatile substances 63.5%, mass fraction of sulfur 4.32%, ash content 0.26%, softening point according to the KiSh method 118°C.

According to the results of experimental coking, the following results were recorded:

- decrease in the ash content of the coal charge by 3.4% (from 8.6% (base) to 5.2% (experimental charge Option 8), respectively, metallurgical coke by 4.2% (11.2% (coke from the base charge ) up to 7.0% (coke from the experimental charge of Option 8);

- an increase in the sintering properties of the charge in terms of the thickness of the plastic layer and dilatometric indicators in terms of the yield range of the charge. Thus, the maximum thickness of the plastic layer was recorded for the charge of Option 3, 5 (increase by 10 mm relative to the base: from 15 to 25 mm). The maximum increase in the yield range of the charge is fixed according to Option 7 (increase by 42°C relative to the base charge: from 85°C to 127°C);

- increase (improvement) in the values of hot strength (CSR) of metallurgical coke by a maximum of 3.1% (from 62.2% (coke from the base charge) to 65.3%) (coke from the experimental charge of Variant 8); by 3.3% (from 62.2% (coke from the base charge) to 65.5%) (coke from the experimental charge of Variant 7).

Increasing the range of plasticity of the coal charge allows adding weakly caking coals to it, which makes it possible to expand the choice of coals for coking and use less valuable grades of coal.

To check the applicability of the invention in the process of forming a charge for the production of metallurgical coke using petroleum coke and petroleum sintering additives, characterized by other properties, additional experimental coking were carried out.

For additional experimental coking according to charge options No. 9-16, petroleum coke and petroleum sintering additive with the following quality characteristics were used:

Petroleum coke - mass fraction of volatile substances 8.2%, mass fraction of sulfur 3.80%, ash content 0.22%;

Oil sintering additive - mass fraction of volatile substances 55.4%, mass fraction of sulfur 4.40%, ash content 0.31%, softening point according to the KiSh method 125°C.

The following compositions of coal mixtures were formed (options No. 9-16), indicated in Tables 3, 4. The quality of the obtained experimental coke was compared with the quality of coke from the base charge.

For additional experimental coking according to charge options No. 17-24, petroleum coke and petroleum sintering additive with the following quality characteristics were used:

Petroleum coke - mass fraction of volatile substances 10.1%, mass fraction of sulfur 3.88%, ash content 0.28%;

Oil sintering additive - mass fraction of volatile substances 45.5%, mass fraction of sulfur 4.31%, ash content 0.40%, softening point according to the KiSh method 165°C.

The following compositions of coal mixtures were formed (options No. 17-24), indicated in Tables 5, 6. The quality of the obtained experimental coke was compared with the quality of coke from the base charge.

Based on the results of additional experimental coking, the following results were recorded:

- decrease in the ash content of the coal charge by 3.4% (from 8.6% (base) to 5.0% (experimental charge Options 16 and 24), respectively, metallurgical coke by 4.8% (11.2% (coke from base charge) up to 6.4% (coke from the test charge of Options 16 and 24);

- an increase in the sintering properties of the charge in terms of the thickness of the plastic layer and dilatometric indicators in terms of the yield range of the charge. Thus, the maximum thickness of the plastic layer was recorded for the charge of Option 13, 14, 22, 23 (an increase of 5-10 mm relative to the base: from 15 mm to 20-25 mm). The maximum increase in the yield range of the charge was recorded according to Options 13-16 and 22 (increase by 42-63°C relative to the base charge: from 85°C to 127-148°C);

- increase (improvement) of hot strength values (CSR) of metallurgical coke by a maximum of 3.9% (from 62.2% (coke from the base charge) to 66.0%) (coke from the experimental charge of Option 15); by 3.4% (from 62.2% (coke from the base charge) to 65.6%) (coke from the experimental charge of Option 13).

The results of the experiments confirm that the use of the charge in accordance with the present invention made it possible to significantly improve the quality of the charge for coking in terms of ash content and sintering properties, as well as to increase the hot strength (CSR) values of the resulting coke.

The exemplary embodiments described are for illustrative purposes only. It will be obvious to the specialist that other embodiments are possible without changing the essence of the invention.

Claims (4)

1. Charge for the production of metallurgical coke, including, wt.%: mixture of coal concentrates 60-98 petroleum coke with a mass fraction of volatile substances from 8 to 12% 1-20 petroleum sintering agent 1-20, moreover, petroleum coke is obtained by delayed coking of heavy oil residues, and petroleum sintering additive is obtained by deep vacuum distillation of the tar visbreaking residue and has a softening temperature according to the KiSh method of at least 105 ° C and a mass fraction of volatile substances from 45 to 65%. 2. The use of the charge according to claim 1 for the production of metallurgical coke.