WO2024155212A1

WO2024155212A1 - Petroleum additive for production of metallurgical coke and coke produced using such additive

Info

Publication number: WO2024155212A1
Application number: PCT/RU2024/050003
Authority: WO
Inventors: Dmitrii Sergeevich VIUKOV; Anton Valerievich GRAKHOVSKII; Elena Viktorovna DENISENKO; Andrei Andreevich PRUS; Anton Vasilievich ROSHCHIN
Original assignee: Public Joint-stock Company "Novolipetsk Steel"
Priority date: 2023-01-20
Filing date: 2024-01-09
Publication date: 2024-07-25

Abstract

The invention relates to the coke industry, namely, to the production of metallurgical coke, production method thereof, and additives that improve the properties of the produced coke. The proposed petroleum additive to a blend for the production of metallurgical coke comprises a heavy petroleum residue processing product, comprising (wt.%): total carbon from 85 to 98, sulfur not exceeding 5, volatiles at least 50, and ash not exceeding 1.5, wherein the petroleum additive has toluene insoluble content (Tl) of 5 to 40 wt. %, quinoline insoluble content (QI) of 0.5 to 20 wt.%, wherein (Tl)/ (QI) exceeds 1, ring and ball (R&B) softening temperature of 80 to 200°C, ring and rod (R&R) softening temperature of 70 to 180°C, and the difference between R&B and R&R softening temperatures of 4 to 20°C. The invention further comprises use of a petroleum additive, a blend for the production of metallurgical coke comprising the petroleum additive, a method for producing metallurgical coke using the petroleum additive, and metallurgical coke produced from the blend comprising the petroleum additive. The technical effect of the invention is to develop a method for producing metallurgical coke from a blend of a certain composition using a petroleum additive that has a controllable balance of necessary and sufficient features to provide a high-quality product (metallurgical coke).

Description

PETROLEUM ADDITIVE FOR PRODUCTION OF METALLURGICAL COKE AND COKE PRODUCED USING SUCH ADDITIVE

The invention relates to the coke industry, namely, production of metallurgical coke, a production method thereof, and additives that improve the properties of the produced coke.

Currently, the main problem of the coke industry is to resolve the issue of maximizing the inclusion of cheaper coals of lower quality, in particular coals with low caking ability, in the initial coal blend, while ensuring the production of coke of the required quality.

A well-known way to solve this problem is to supplement the blend with organic additives of petroleum origin, so-called petroleum caking additives.

In general, the term “caking” with respect to coal means filling the pores of a material with a substance and eliminating them at high temperatures due to the spontaneous compaction of a dispersed porous body. The coking ability of coal is understood as its ability to transform into a plastic state at high (over 350°C) temperatures without air access, resulting in the formation of a continuous viscous mass, which after hardening (coking) turns into coke. The caking and coking of non-caking or poorly caking coals use petroleum caking additives, which main purpose is to act as a low-viscosity adhesive that fills the pores in the porous caked material (coal blend) and binds small particles of components into larger ones, while providing the necessary after curing features inherent in cokes as heat sources, drainage additives, and metal reducers in metallurgical processes. Thus, to perform its function, a caking additive should have the following properties:

- adhesive properties when heated, sufficient for “gluing” coal particles (plasticity when heated);

- necessary mechanical features (strength, fractional composition of particles, etc.) sufficient for use in existing technological processing schemes;

In general, the coal blend additives comprise various organic additives such as solid waste from coke production, petcoke, non-caking coals, and other additives, which use ensures the coke strength features and reduces the production costs thereof.

According to various references, coke manufacturers prescribe the following standard requirements for additives:

- ash content;

- total sulfur content; - volatile content;

- water content;

- caking ability; and

- softening temperature.

The sulfur content is a parameter limited by coke consumers (metallurgical industry) to a level not exceeding 5% (sulfur pass into coke and then to metal, whereby additional purification costs are required). Thus, the sulfur content of the additive severely limits the amount of additive that can be added to the coke to meet the coke requirements of various application fields.

The volatile content is a parameter that has a dual effect. On the one hand, its increase negatively affects the consumption coefficient of the coking process (decrease in coke yield due to the removal of volatiles from it during the heating process), an increase in capital and operating costs due to the need to increase the weight of materials moved along the process chain and subjected to preliminary preparation, and then loaded into the coking chamber; An increase in gas yield also leads to an increase in the size of auxiliary equipment for capturing and neutralizing coke oven gas, as well as to the likelihood of deterioration in coke strength due to cracking and increased porosity. On the other hand, a positive effect of the proportion of volatile substances on caking and coking properties is noted for the additives based on petroleum products.

The amount of ash (ash content) of an additive is a negative parameter, which increase leads to a decrease in the carbon content in the coke, an increase in coke consumption and an increase in the yield of slag in the blast furnace, in some cases, to the need to introduce additives into the blast furnace in order to adjust the slag basicity (CaO/SiCh ratio), and, in general, to a decrease in productivity and an increase in the cost of the blast furnace process. However, there is a certain minimum level of minerals (ash) that are concentrated in heavy petroleum products.

The water content (moisture) is a parameter that is not decisive for the process of producing or using the additive, however, excess water content in the coal blend comprising the additive has a negative impact on heat consumption both due to heat loss via water evaporation and by lengthening the coking period ( coal blend layer temperature would not rise above 100°C until the moisture has completely evaporated, which delays the transfer of heat to the deeper layers of the coal blend). Another negative effect is the larger volume of steam, which increases the volume of coke oven gas leaving the coking chamber before the bulk of the moisture has evaporated. Furthermore, high moisture creates difficulties during storage and transportation of material in winter. The caking ability is the main feature that determines the quality of caking components, which depends mainly on the composition and morphology of the initial products.

The softening temperature means that, for successful caking, an additive should have low viscosity and good adhesion at the process temperature in order to fill quickly the pores between the coal blend particles during the heating process. But an addition of a low-viscosity component into the coking coal blend at temperatures below 100°C can lead to rapid flow of this component into the lower part of the coking chamber and a decrease in the quality of the coke produced in the upper part, as well as cause problems during transportation and storage, especially in summer due to possible sticking of the material. At the same time, if the additive begins to soften at a temperature significantly higher than the coal caking onset temperature (350°C), then during the heating process its effective operation area decreases since the coal blend forms a skeleton and loses its caking ability at a temperature over 550°C.

Thus, one can state that not a single individual feature allows predicting the quality of the caking additive and providing the necessary balance of caking and strength properties of the additives as determined by the specific use of coke, or providing the full information about the ways to improve the processes of producing and using these objects, but a large volume of experimental work should be carried out to study other factors that influence the properties of caking additives and to search for non-obvious solutions to ensure the required set of properties.

Prior Art

RU No. 2355729 discloses use of petroleum coke with a volatile yield in the range of more than 14% and less than 25% as a coking additive to coal blends used for the production of metallurgical coke. When used, this additive allows replacing grade K coal with a cheap byproduct (petroleum coke), recycling of petroleum coke, and reducing the cost of the coking process.

RU No. 2411283 discloses use of a delayed semi-coking product of heavy petroleum residues with a volatile content of 12 to 25% and a plasticity temperature range of at least 120°C as an additive to coal blends used for the production of metallurgical coke with improved properties when using mixtures of different coals.

The above-mentioned patents do not disclose any information about the influence of other additive factors on the properties of the produced coke. RU No. 2637965 discloses an petrolium coking additive comprising a product of delayed semi-coking of heavy petroleum residues, characterized in that the product of delayed semicoking of heavy petroleum residues is produced by holding for 14 to 24 hours at a temperature of 450 to 500°C with the coking chamber recirculation coefficient of 1.05 to 1.2 and characterized by a volatile content of 14 to 28% and a Gray-King coke typenot lower than G.

RU No. 2455337 discloses a method for producing a petroleum additive in a coking coal blend, comprising visbreaking of the petroleum residue to produce a carbonaceous residue having an R&B (ring and ball) softening temperature above 80°C, which is granulated to form the target product, characterized in that visbreaking is carried out at a temperature of 440 to 490°C, visbreaking products are fed into a distillation column, into the inlet flow of which a cooler is supplied to maintain the temperature of visbreaking products not higher than 400°C, the visbreaking residue from the distillation column is sent to a vacuum evaporator to produce a vacuum residue having an R&B softening temperature above 80°C.

RU No. 2452760 discloses a method for producing a petroleum caking additive into a coking coal blend, comprising visbreaking of tar to produce a visbreaking residue, vacuum distillation of the visbreaking residue to produce a vacuum visbreaking residue with an R&B softening temperature of 60 to 90°C, characterized in that the vacuum visbreaking residue subjected to deasphalting to produce asphalt as the target product.

RU No. 2735742 discloses a method for producing a coal blend for coking using a petroleum caking component and coal concentrates/coals, characterized in that the product produced by oxidizing the vacuum residue of visbreaking tar with a volatile yield in the range of 30-70% is used as a petroleum caking component, which is introduced into the coal blend at the following ratio of components, wt.%: petroleum caking component: 5 to 40, coal concentrates/coals: balance rest.

RU No. 2769188 discloses a coal blend composition for producing metallurgical coke, comprising a mixture of coals of caking grades G (gas), and/or GF (gas fat), and/or GFL (gas fat lean), and/or F (fat) and lean grades CLC (coking low-caking) and/or LC (lean caking) in a weight ratio of 1:1.15 in an amount of 60 to 93.5 wt.% and petroleum coke produced by delayed coking of heavy petroleum residues, with a caking index of 75 to 100 units in an amount of 6.5 to 40.0 wt.%

RU No. 2627425 discloses a coal blend for producing metallurgical coke, comprising a mixture of coal and a special additive, characterized in that the special additive comprises petroleum residues and petroleum coke with the following ratio of the mixture components, wt.%: petroleum coke from 30.0 to 1.0, petroleum residues from 30.0 to 1.0, coal mixture from 40.0 to 98.0, wherein, petroleum residues are characterized by an ash content not exceeding 2.5%, a volatile yield not exceeding 90%, a sulfur content not exceeding 5%, a Roga index of at least 10, and petroleum coke is characterized by an ash content not exceeding 2.5%, a volatile yield not exceeding 25%, sulfur content not exceeding 5%, and coke produced from this blend has CRI (coke reactivity index) of 31.4 to 36.3% and CSR (coke strength after reaction) of 47.9 to 52.4%.

JP 2006269494 (A) discloses a coke produced by delayed coking using coal-based tar or petroleum-based heavy oil having a quinoline insoluble content of 0.1% or less, which is used for the manufacture of electrodes. The application provides the information relating only to electrode coke, which has a high degree of anisotropy, but does not teach anything about the effect of the quinoline insoluble content not exceeding 0.1% on the quality of metallurgical coke with increased requirements for mechanical strength.

RU No. 2663145, which is the closest prior art of the claimed invention discloses a method for preparing a coking blend to produce a coking ready product in the form of a singlecomponent charge or as part of a multi-component blend, which method comprises mixing a petroleum caking additive with low-caking coal grades CC (coking low-caking), and/or CLCLM (coking low-caking low metamorphosed), and/or CL (coking lean), and/or LL (lean low-caking), and/or LC (lean caking) at the following ratio of components, wt.%:

- petroleum caking additive (1 to 30),

- coal grades CC, and/or CLCLM, and/or CL, and/or LL, and/or LC (99 to 70), wherein, the petroleum caking additive is a petroleum refining residue with the following features: ash content not exceeding 2.5%; volatile yield not exceeding 90%; sulfur content - not exceeding 5%; R&B softening temperature at least 40°C. Coke produced from the claimed blend has CRI of 28 to 32% and CSR of 54 to 60%.

The analysis of the cited prior art references demonstrated that they solve only narrow particular problems of using specific additives introduced into the blend for coke production. The prior art discloses no technical solutions that offer tools for influencing the coke production process as a whole by changing an individual key feature, in particular related to the properties of the caking additive. Both the prior art and our research show a non-obvious influence of the composition and properties of the additive on the process of producing metallurgical coke and final features thereof. On the one hand, there are data in literature on the influence of individual parameters of a certain type of additive on the production of coke and final properties thereof. However, the prior art does not allow making any conclusions about the resulting effect of a set of different additive parameters. Some prior art references disclose some additive components as having a negative effect and recommend eliminating them completely, while others show that some content of the same component has a positive effect. Apparently, the multiple-valued influence of one or another parameter is associated with the complex and often unpredictable composition and properties of additives being a by-product of oil production, where the variable feedstock and processing parameters thereof can affect the by-product composition and properties in a multiple-valued manner. Both research and production activity of the authors allowed noticing that different batches of additives, even from the same manufacture, can behave differently in the blend. Often, the same component/parameter can have a positive effect on some blend processes and a negative effect on others, while the content of some substances can offset the negative impact of such a component/parameter.

In view of the above information, we can conclude that there is still no solution for the problem of creating a petroleum caking additive with a controllable balance of features, necessary and sufficient to ensure the production of metallurgical coke with the necessary balance of properties based on cheap available coal and petroleum raw materials.

The objective of the invention is to develop a petroleum additive for coking a certain blend composition that would allow producing metallurgical coke of improved quality using inexpensive available coal and petroleum raw materials.

The technical effect of the invention is to develop a method for producing metallurgical coke from a certain blend composition using a petroleum additive that has a controllable balance of necessary and sufficient features to provide a high-quality product: metallurgical coke.

During the present work, the authors discovered that the specified solution to the problem and achievement of the technical effect can be provided by using for production of metallurgical coke a petroleum additive with specific properties, which distinctive feature is that the additive has a controllable toluene and quinoline insoluble content and ratio with a certain volatile content and R&B (ring and ball) and R&R (ring and rod) softening temperatures. The authors discovered that additives with certain toluene and quinoline insoluble content and ratio have a positive effect if the volatile content in this additive is 50 to 85 wt.%, and the R&B and R&R softening temperatures are 80 to 200°C and 70 to 180°C, respectively.

In particular, the authors found that the toluene insoluble content of 5 to 40 wt.% and quinoline insoluble content of 0.5 to 20 wt.% in such a petroleum additive leads to a higher coke caking ability and improves the strength properties thereof

There are no precise literature data or studies on the effect of the toluene and quinoline insoluble content on the caking properties of certain petroleum additives in the process of metallurgical coke production. Only few references comprise the conflicting data on the effect of such substances on the properties of pitch. For example, “Carbonaceous Structural Materials”, Moscow, 1975, pages 117-120) discloses the ambiguous influence of quinoline insoluble content in the coal tar pitch on the formation of the properties of hydrocarbon materials. In particular, on the one hand, quinoline insolubles (ai) are considered as contaminants in pitch, and therefore it is proposed to remove them from products used for the pitch production; on the other hand, it is proposed to improve the properties of pitch by supplementing the raw materials for production thereof with insoluble fine powders of soot or graphite. The work experimentally confirmed the different effects of the ai fraction on the properties of pitches having different particle size distributions: a higher content of the ai fraction led to worsening properties for fine-grained materials, whereas coarse-grained materials showed improved strength properties of the produced coke up to a certain content due to the fact that the ai fraction acted as a fine surfactant filler, which reduced porosity and increased the strength of the material.

The above-mentioned document notes that there is a fundamental possibility of targeted regulation of the properties of carbonaceous materials used for coke production by changing the content of the ai fraction therein. However, the document does not disclose that the metallurgical coke quality is affected by the content of the ai fraction in certain blend composition formed from a mixture of coals in the presence of a caking additive with a controllable content of the ai fraction.

Other prior art documents have also failed to provide a consistent approach to assessing the effects of quinoline insolubles on the various mixtures of carbonaceous materials used to produce metallurgical coke.

Without being limited to any theory, the authors have put forward the assumption that toluene insolubles in the specified weight range act as an additional plasticizer for the coal components of the blend during the high-temperature coke production process, and, having good adhesion, wet the solid particles of the blend and thereby improve the caking of the blend as a whole, and quinoline insolubles, if used in strictly controlled quantities, when the temperature rises, act as centers that increase internal friction in the additive mass and do not allow the molten mass to flow down and, furthermore, upon further heating (above the caking region), quinoline insoluble particles act as reinforcing fillers during the coking process, whereby an increase in the strength of metallurgical coke is achieved. Thus, by changing the quinoline and toluene insoluble content, it is possible to control the set (balance) of the features of the petroleum additive, ensuring the required quality of the coke produced.

Summary of the Invention

Thus, the aforementioned problem is solved and the achievement of the technical effect is provided through the use of a petroleum additive to the blend for the production of metallurgical coke, the additive comprising a heavy petroleum residue processing product comprising (wt.%): total carbon from 85 to 98, sulfur not exceeding 5, volatiles at least 50, ash not exceeding 1.5, characterized in that the petroleum additive has toluene insoluble content (a) from 5 to 40 wt.%, quinoline insoluble content (ai) from 0.5 to 20 wt.%, wherein (a)/(ai) exceeds 1, and R&B softening temperature from 80 to 200°C, R&R softening temperature from 70 to 180°C, wherein the difference between the R&B and R&R softening temperatures ranges from 4 to 20°C.

Preferably, the heavy petroleum residue product is substantially amorphous.

Preferably, the volatile content is preferably 60 to 85 wt.%, more preferably 65 to 80 wt.%.

Preferably, the sulfur content is preferably less than 3 wt.%, more preferably 1 to 3 wt.%.

Preferably, the water content does not exceed 5 wt.%, preferably does not exceed 2 wt.%, more preferably is less than 1 wt.%.

Preferably, the ash content does not exceed 1 wt.%, more preferably does not exceed 0.5 wt.%. Preferably, the toluene insoluble content (a) is 10 to 35 wt.%, more preferably is 15 to 30 wt.%, and the quinoline insoluble content (ai) is preferably 0.5 to 15 wt.%, more preferably is 0 to 10 wt.%.

Preferably, (a)/(ai) exceeds 2, more preferably (a)/(ai) exceeds 5.

Preferably, the petroleum additive comprises particles, wherein the sum of the length, width and height dimensions is 3 to 600 mm, preferably it is 15 to 200 mm, more preferably it is 15 to 100 mm.

Preferably, the R&B softening temperature is at least 100°C, and more preferably it is at least 115°C.

Preferably, the R&R softening temperature is at least 90°C, and more preferably it is at least 105°C.

Furthermore, to solve the above problem and achieve the technical effect, it is proposed to use the above petroleum additive as an additive to the blend for the production of metallurgical coke.

Furthermore, to solve the above problem and to achieve a technical effect, a blend for the production of metallurgical coke is proposed, comprising: a caking component from 6.0 to 47.0 wt.%, a coke component from 10.0 to 35.5 wt.%, and a lean component from 37.5 to 65 wt.%, wherein the caking component comprises a petroleum additive according to any of claims 1-11 or a mixture thereof with caking coals, the coke component comprises coke coals or a mixture thereof with petroleum coke, the lean component comprises leaning coals or mixtures thereof with other lean carbonaceous substances, over 50% petroleum additive particles have a fraction of 3 mm or less.

Preferably, said mixture comprises components in the following ratio, wt.%: the caking coals from 5.0 to 22.0, the coke coals from 5.0 to 20.5, the leaning coals from 37.5 to 65, the petroleum coke from 5.0 to 15.0 the petroleum additive from 1.0 to 25.0 Preferably, in said mixture, preferably more than 65% particles in the petroleum additive, and more preferably more than 70% particles in the petroleum additive have the fractional composition of 3 mm or less.

Furthermore, to solve the above problem and to achieve the technical effect, a method for producing metallurgical coke is proposed, comprising the steps of:

(a) forming a blend by mixing 6.0 to 47.0 wt.% caking component comprising the petroleum additive according to claim 1 or a mixture thereof with caking coals, 10.0 to 35.5 wt.% coke component, 37.5 to 65 wt.% lean component, wherein the coke component comprises coke coals or a mixture thereof with petroleum coke, and the lean component comprises lean coals or their mixtures with other lean carbonaceous substances;

(b) producing metallurgical coke from the blend formed in step (a).

Preferably, before step (a), the parameters of the petroleum additive are adjusted to the values specified in claim 1 by selecting the petroleum additive composition via mixing the required amount of heavy petroleum residue processing products with different parameter values.

Preferably, the heavy petroleum residue processing products are mixed in a separate mixer before forming the blend.

Preferably, the resulting petroleum additive is granulated.

Preferably, step (a) includes adjusting the parameters of the petroleum additive to the values specified in claim 1 by selecting the composition of the petroleum additive via mixing the required amount of heavy petroleum residues with different parameter values.

Preferably, the heavy petroleum residue processing products are mixed while grinding the blend.

Preferably, the heavy petroleum residue processing products comprise products of vacuum stripping and/or thin film evaporation of heavy residues from advanced petroleum refining.

Preferably, in step (a), the blend components are ground in such a way that preferably over 65% particles, and more preferably over 70% particles comprise the fractional composition of 3 mm or less.

Preferably, the petroleum additive may be ground together with other components of the blend or separately, followed by mixing in the ground form. Preferably, in step (a), the coals, petroleum coke and petroleum additive are mixed in the following ratio of components, wt.%: caking coals from 5.0 to 22.0, coke coals from 5.0 to 20.5, lean coals from 37.5 to 65, the petroleum coke from 5.0 to 15.0, the petroleum additive from 1.0 to 25.0.

Furthermore, to solve the above problem and to achieve a technical effect, metallurgical coke is proposed as produced from a blend comprising the petroleum additive according to claim 1, wherein the sulfur content does not exceed 5%, CRI does not exceed 40%, and CSR value is at least 40%.

Detailed Description

The present application discloses a petroleum caking additive (1) for use in a blend comprising readily available inexepensive grades of coal so that said blend can be used in the metallurgical coke production processes.

To perform its function, the petroleum additive should satisfy a number of requirements, in particular, have the following features:

The total carbon content is 85 to 98 wt.%. The total carbon in the context of the claimed invention means the total content of carbon atoms in the additive, including both carbon itself (for example, coal, graphite, soot, etc.) and those included in the hydrocarbon molecules that form petroleum products (aliphatic, aromatic, cyclic homo- and heterocompounds, etc.). When the carbon content is below 85% the content of other elements (nitrogen, oxygen, hydrogen, sulfur, heavy metals) that are not valuable for the use of additives in the metallurgical coke production increases, and the carbon content over 98% will deteriorate economy of production of the additive.

The sulfur content in the additive is preferably kept at the level below 5 wt.%. A higher sulfur content is also possible, but this would limit the amount of additive used in the blend and reduce the amount of caking coal replaced by the additive. Sulfur can enter the additive composition from the original petroleum feedstock and be present in the form of elemental sulfur and various sulfur compounds, including metal sulfides, hydrogen sulfides, mercaptans, etc. Furthermore, an increase in sulfur content can cause accelerated corrosion of equipment. In some cases, the petroleum caking additive according to the invention may have a sulfur content of preferably less than 3 wt.%, more preferably 1 to 3%, since reducing its content below 1% is possible, but requires a complex purification process, which complicates and increases the cost of additive production.

Volatile compounds (substances) may comprise both inorganic compounds (hydrogen, oxygen, carbon dioxide, nitrogen oxides, sulfur, etc.) and organic compounds (aromatic, aliphatic, cyclic, etc., in particular, benzene, toluene, xylenes, ethylene, propylene, cyclohexane, etc.). The volatile content in the additive should be at least 50 wt.%. The volatile content below 50 wt.% worsens the caking properties of the additive, and further leads to an increase in capital and operating costs in the production of the additive. However, a further increase in the volatile content can negatively affect the consumption coefficient of the coking process, since the volatile components of the additive during the coking process are almost completely converted into gas and tar, reducing the yield of metallurgical coke. In some cases, the petroleum additive may preferably comprise 60 to 85 wt.% volatiles, more preferably 65 to 80 wt.%.

The ash content should not exceed 1.5 wt.%. The ash content over 1.5 wt.% leads to a decrease in the efficiency of using the additive in the coking process due to a decrease in the content of active components in the coking blend, as well as to a decrease in the total carbon content in the coke and, ultimately, to a decrease in the efficiency of the blast furnace process. In some cases, the petroleum additive may preferably comprise no more than 1 wt.% ash, more preferably no more than 0.5 wt.% ash.

The toluene insoluble content (a) is 5 to 40 wt.%, preferably 10 to 35 wt.%, more preferably 15 to 30 wt.%. The toluene insoluble content below 5% leads to a decrease in the caking ability of the additive and, accordingly, a decrease in the caking ability of the blend, which requires a higher caking coal content in the composition, and the toluene insoluble content over 40 wt.% leads to a decrease in the strength of coke and a decrease in the yield thereof, because some of these substances will be removed with the tar and coke oven gas during the coking process.

The quinoline insoluble content (ai) comprises particles of carbon (soot, coke), metals and insoluble metal salts, complex polynuclear aromatic resins, etc. The quinoline insoluble content is 0.5 to 20 wt.%. The quinoline insoluble content below 0.5 wt.% can negatively affect the viscosity of the additive during heating, its drainage and uneven distribution in the volume of the blend during heating in the coking chamber, and, as a result, lead to a decrease in the quality of coke, and the quinoline insoluble content over 20 wt.% will lead to a deterioration in the blend caking ability, as well as to an excessive number of mechanical stress concentration centers in the coke and an increased yield of coke fines. In some cases, the petroleum additive may preferably comprise 0.5 to 15 wt.% quinoline insolubles, more preferably 0.5 to 10 wt.%. In the claimed invention, the ratio (a)/(ai) exceeds 1. If (a)/(ai) does not exceed 1, the petroleum additive will not have sufficient caking properties. In some embodiments, preferably (a)/(ai) exceeds 2, more preferably (a)/(ai) exceeds 5.

The R&B or R&R softening temperature is a feature characterizing the plastic “adhesive” properties of the additive, which affects the ability of the additive to pass into a viscous-flow state, to glue particles of non-caking coals, and to fill the pores therebetween. Meanwhile, a point was made of the fact that the numerical values of the R&B and R&R softening temperatures for the same additive may differ from each other. Without being limited to any theory, an assumption was made that such a difference is due to the peculiarity of the measurement objects, namely, the R&B softening temperature is more accurate for flowing liquid mixtures (for example, tar), which are closer to Newtonian liquids, while the R&R softening temperature, which is measured by the method using a device in a penetration process, is more accurate for non-Newtonian liquids (for example, pitch). In the claimed invention, the petroleum caking additive is a mixture of various substances, therefore, to ensure greater correctness, both temperatures are disclosed in the claims. In accordance with the present invention, the R&B softening temperature is 80 to 200°C, the R&R softening temperature is 70 to 180°C, and the difference between the R&B and R&R softening temperatures should range from 4 to 20°C.

The lower limit of the R&B and R&R softening temperature is determined by the possibilities of transportation and storage of the caking additive, including the risks associated with the sticking of material in cars and bunkers, sticking to equipment (conveyors, dispensers, etc.) due to heating of the equipment, for example, in the sun, as well as the risk of intensive drainage of the molten additive formed under the influence of high temperatures during the process of coking into the lower part of the coking chamber, which can lead to the production of coke having different properties in the upper and lower parts of the chamber and cause the risk of insufficient caking of the blend in the upper part. At softening temperatures above the maximum values, the additives will not have the necessary caking properties. In some cases, the R&B softening temperature is preferably at least 100°C, more preferably at least 115°C, and the R&R softening temperature is preferably at least 90°C, more preferably at least 105 °C. The petroleum caking additive of the invention is substantially amorphous. It may exist in the form of pieces or particles whose sum of dimensions in length, width and height is 3 to 600 mm, preferably 15 to 200 mm, more preferably 15 to 100 mm.

The water content does not have a significant effect on the coking process, but, in general, a high water content can cause a slight increase in heat loss due to water evaporation and prolongation of the coking period, as well as create problems during storage and transportation of material in winter. The petroleum additive of the invention may generally comprise no more than 5 wt.% water, preferably no more than 2 wt.%, more preferably less than 1 wt.%.

The petroleum caking additive according to the invention can be used to form a blend for the production of metallurgical coke.

The blend for producing metallurgical coke in accordance with the claimed invention is a coking mixture, comprising: a caking component from 6.0 to 47.0 wt.%, a coke component from 10.0 to 35.5 wt.%, and a lean component from 37.5 to 65 wt.%, wherein:

- the caking component comprises a petroleum additive according to the present invention or a mixture thereof with caking coals,

- the coke component comprise coke coals or a mixture thereof with petroleum coke, and

- the lean component comprises leaning coals or mixtures thereof with other leaning carbonaceous substances.

It is more preferable to use a blend with the following ratio of components, wt.%:

- the caking coals from 5.0 to 22.0,

- the coke coals from 5.0 to 20.5,

- the lean coals from 37.5 to 65,

- the petroleum coke from 5.0 to 15.0, and

- the petroleum caking additive from 1.0 to 25.0.

Moreover, more than 50 wt.% of the blend particles have a fraction composition of 3 mm or less, that is, the size of 50 wt.% blend particles is 3 mm or less. If less than 50 wt.% blend particles have the fraction composition of 3 mm or less, this would worsen the blend component mixing uniformity and further decrease the produced coke quality. In some applications, the petroleum caking additive may have a particle size distribution with the fraction of 3 mm or less comprising preferably over 65% particles, more preferably over 70% particles.

The blend in accordance with the claimed invention is used to produce metallurgical coke. The specification discloses the overall process, comprising the feedstock processing and the production of petroleum caking additives, the formation of a blend and the production of the final product (metallurgical coke). See below a detailed description of the process (method) features.

The feedstock for the production of petroleum caking additives is not limited within the scope of the claimed invention. In particular, it may comprise heavy residues from advanced petroleum refining, for example, products of vacuum distillation of unconverted residue from hydrocracking of tar, visbreaking, heavy pyrolysis resin, etc. In accordance with the claimed invention, further feedstock processing can be carried out by vacuum distillation, and also using film evaporation. For the avoidance of doubt, it is clarified that the scope of protection of the claimed invention covers both the implementation of each of the specified operations separately and combined use thereof. The caking additive produced in step (a) can be subjected to granulation, crushing or other process operations to form additive particles with a fractional composition determined by the process features of metallurgical coke production. Preferably, the blend additive particle size does not exceed 200 mm.

To form the blend in step (b), the blend components are ground and mixed in a mixer, which design is not limited within the scope of the claimed invention. The usable coals comprise, without limitation, caking coals, coking coals, and lean coals. The petroleum coke can use, in particular, without limitation, products produced from the coking of residual straight-run, cracking, pyrolysis products of petroleum refining and oil production extracts. Coke, graphite, dust from gas treatment facilities of coke production plants, etc. can be used as waste carbonaceous substances.

In some cases, the petroleum caking additive can be ground in a separate apparatus and an already ground additive can be introduced into the blend, wherein over 50 wt.% resulting particles, preferably over 65, more preferably 70 wt.% particles, will have the fractional composition of 3 mm or less.

A distinctive feature of the method is the need to ensure the presence of additive in the blend during the coking process, wherein the additive is characterized by a set of features according to claim 1, in particular by the specific toluene and quinoline insoluble content as well as the volatile content and R&B and R&R softening temperatures, since said values provide a solution to the technical problem and achievement of the technical effect of the claimed invention. The main obstacle in this case is the inability to influence this set of additive features when using a ready-made additive from the outside. Therefore, either in step (a) or before, the input control and regulation of these additive parameters is carried out by selecting the additive composition by mixing the required amount of heavy petroleum residue processing products with different values of these parameters. In this case, the additives can be mixed via grinding of the blend.

Next, the formed blend is sent for coking to produce metallurgical coke. The process conditions and the used equipment, including control and measuring instruments, are not limited in the terms of the claimed invention and are determined by the features of the raw materials and the specific coke manufacturing processes.

The coal caking temperature lies in the range of 350 to 550°C, where the heated coal transforms into a viscoplastic state. The introduction of petroleum additives with an intrinsic softening temperature below 200°C into the blend composition leads to an expansion of the caking temperature range not only due to the fact that the heated additive itself transforms into a plastic state much earlier, but also due to a decrease in the transition temperature of the caking components of coal partially dissolving in the additive that has passed into a viscoplastic state. Thus, during the heating process, the blend remains in a viscoplastic state for much longer, while both the number and strength of bonds between individual grains of the blend increase, and the conditions improve for heat and mass transfer throughout the blend bulk. In turn, this leads to an improvement in coke quality parameters determined after reaction with carbon dioxide to form carbon monoxide according to GOST R 54250 (or equivalent), namely: a decrease in the coke reactivity index (CRI), as well as an increase in the coke strength after reaction (CSR), which further allows reducing the consumption of such coke during blast furnace smelting.

The metallurgical coke produced according to the claimed method using the claimed petroleum additive and the formed blend has CRI not exceeding 40 wt.% and CSR of at least 40 wt.%. Decreasing CSR to below 40 wt.% and increasing CRI to above 40 wt.% will increase the amount of coke used in the blast furnace.

Description of Research Methods

Table 1 represents the used research methods.

Examples of practical use of the invention

NPA: no petroleum additive Table (continued)

Table (continued)

n the above table with examples, unprimed numerals refer to examples of a blend without a caking additive corresponding to claim 1, same primed numerals refer to a blend adjusted to take into account the input of petroleum additives corresponding to the parameters from claim 1. In comparative examples 5-7, the blend was supplemented with other petroleum additives that did not meet the entire set of criteria set out in claim 1. These examples are given to compare the behavior of additives that meet the entire set of criteria from claim 1 (“examples according to the invention”) and those that partially meet (“comparative examples”).

The first part of the table shows the criteria, including those from the claims, and the actually measured parameters of the additives, followed by variants of the blend composed in accordance with the claims and the quality parameters of the coke produced from such a blend. The arrows indicate, respectively, an improvement (j¹) or a deterioration (J,) of the value next to which the arrow is located, compared to the base one (in the blend without the additive that meets claim 1).

In view of the given examples, the following conclusions can be made.

1. The introduction of a petroleum additive into the blend that meets the entire set of features according to claim 1, makes it possible to reduce or completely replace the caking coals in the blend while simultaneously increasing the share of cheap lean coals. Meanwhile, there are obvious improvements in almost all coke quality parameters. The use of other petroleum additives that do not meet the entire set of properties according to claim 1, although it makes it possible to produce coke of comparable quality, but, firstly, does not allow eliminating or at least significantly reducing the share of caking coals and, secondly, to achieve coke of the same quality, the introduced additives 6 and 7 replace non-scarce and cheap lean coals, and additive 5 cannot be used on an industrial scale (see conclusion 4 below). Thus, there is only a partial solution to the invention problem (improving the quality of coke using cheap raw materials).

2. The introduction of a petroleum additive into the mixture according to claim 1 significantly improves the plastic features of the entire mixture, which is evident from the improvement in parameter Y, while other (A, B) petroleum additives do not affect this feature.

3. As it can be seen, different additives have different R&B and R&R values that make it possible to control these parameters by combining materials from different batches or from different suppliers to select the optimal values.

4. Example 5 shows the results of testing an additive that differs from the additives in examples 3-4 primarily in its significantly lower softening temperature. Comparing the composition of the blend and the quality of the coke produced in the experiment, it can be seen that it is possible to produce coke of comparable quality to examples 3-4, however, during the experiment, sticking of the additive during the preparation process was noted along with strong adhesion to the equipment used to carry out the study. It is impossible to operate the industrial equipment when using an additive with such properties.

5. An increased ratio (a)/(ai) with comparable other features (examples 3-5) allows significant reducing and even complete eliminating the caking coals, while with a larger (a)/(ai) (25 in the example 5 and 11 in example 4) the quality of the coke is better than the quality of the coke produced by introducing a 20% additive with the ratio (a)/(ai) = 8 (example 3). This allows maximizing the share of lean coals (53% in example 4" and 55% in example 5"), as well as producing coke with the best parameters in the entire series of examples for CSR (68.8%) and CRI (24.1%). The introduction of other additives (examples 6-7), even in combination with the caking additive according to claim 1 (in total up to 30% in example 2") does not allow achieving a similar quality of coke.

6. As can be seen from examples 6-7, the low volatile content in them leads to an increase in the temperature at which the additive begins to soften and does not allow producing a caking effect, and coke, comparable in quality to coke using additives that fully comply with claim 1, is produced by replacing only the least scarce and cheaper leaning group of coals in the blend. At the same time, the quality of coke at any consumption of additives is still somewhat lower than that in examples 4-5, and the use of additive 7 generally minimizes the quality parameters, despite the positive effect of using additives with such a quantity of volatiles stated in some references.

Thus, despite the fact that each parameter of the caking additive affects the quality of the final product (coke) and the composition and cost of the coking blend, only the correct (optimal) combination of features allows providing the best technical effect and best solution for the invention problem.

Claims

1. A petroleum additive to a blend for the production of metallurgical coke comprising a heavy petroleum residue processing product, comprising (wt.%): total carbon from 85 to 98, sulfur not exceeding 5, volatile substances at least 50, ash not exceeding 1.5, characterized in that the petroleum additive has toluene insoluble content (a) from 5 to 40 wt.%, quinoline insoluble content (ai) from 0.5 to 20 wt.%, wherein (a)/(ai) exceeds 1, and

R&B softening temperature from 80 to 200°C, R&R softening temperature from 70 to 180°C, wherein the difference between the R&B and R&R softening temperatures ranges from 4 to 20°C.

2. The petroleum additive according to claim 1, wherein the heavy petroleum residue processing product is essentially amorphous.

3. The petroleum additive according to claim 1, wherein a content of the volatile substances preferably does not exceed 60 to 85 wt.%, more preferably 65 to 80 wt.%.

4. The petroleum additive according to claim 1, wherein a content of the sulfur preferably does not exceed 3 wt.%, more preferably 1 to 3 wt.%.

5. The petroleum additive according to claim 1, wherein a content of the water does not exceed 5 wt.%, preferably does not exceed 2 wt.%, more preferably does not exceed 1 wt.%.

6. The petroleum additive according to claim 1, wherein a content of the ash preferably does not exceed 1 wt.%, more preferably does not exceed 0.5 wt.%.

7. The petroleum additive according to claim 1, wherein the toluene insoluble content (a) is preferably 10 to 35 wt.%, more preferably 15 to 30 wt.%, and the quinoline insoluble content (ai) is preferably 0.5 to 15 wt., more preferably 0.5 to 10 wt.%.

8. The petroleum additive according to claim 1, wherein (a)/(al) exceeds 2, more preferably (a)/(al) exceeds 5.

9. The petroleum additive according to any one of claims 1 to 8, wherein particles of the petroleum additive have a sum of dimensions (length, width and height) of 3 to 600 mm, preferably 15 to 200 mm, more preferably 15 to 100 mm.

10. The petroleum additive according to claim 1, wherein the R&B softening temperature is preferably at least 100°C, more preferably at least 115°C.

11. The petroleum additive according to claim 1, wherein the R&R softening temperature is preferably at least 90°C, more preferably at least 105°C.

12. Use of a petroleum additive according to any one of claims 1 to 11 as an additive to a blend for the metallurgical coke production.

13. A blend for the metallurgical coke production, comprising: a caking component from 6.0 to 47.0 wt.%, a coke component from 10.0 to 35.5 wt.%, and a lean component from 37.5 to 65 wt.%, wherein:

- the caking component comprises the petroleum additive according to any of claims 1 to 11 or a mixture thereof with caking coals,

- the coke component comprises coke coals or their mixture with petroleum coke,

- the lean component comprises lean coals or their mixtures with other lean carbonaceous substances, more than 50% of particles of the petroleum additive have a fractional composition of 3 mm or less.

14. The blend according to claim 13, wherein the ratio of components, wt.%:

- the caking coals 5.0-22.0

- the coke coals 5.0-20.5

- the lean coals 37.5-65

- the petroleum coke 5.0-15.0

- the petroleum additive 1.0-25.0

15. The blend according to claim 13 and claim 14, wherein preferably more than 65% of the particles of the petroleum additive and more preferably more than 70% of the particles of the petroleum additive have the fractional composition of 3 mm or less.

16. A method for producing metallurgical coke, comprising steps of:

(a) forming a blend by mixing 6.0 to 47.0 wt.% caking component comprising the petroleum additive according to claim 1 or a mixture thereof with caking coals, 10.0 to 35.5 wt.% coke component, and 37.5 to 65 wt.% lean component, wherein the coke component comprises coke coals or a mixture thereof with petroleum coke, and the lean component comprises lean coals or mixtures thereof with other lean carbonaceous substances;

(b) producing metallurgical coke from the blend formed in step (a).

17. The method according to claim 16, wherein, before step (a), parameters of the petroleum additive are adjusted to the values specified in claim 1 by selecting the petroleum additive composition via mixing the required amount of heavy petroleum residue processing products with different parameter values.

18. The method according to claim 17, wherein the heavy petroleum residue processing products are mixed in a separate mixer before forming the blend.

19. The method according to claim 17, wherein the resulting petroleum additive is granulated.

20. The method according to claim 16, wherein step (a) includes adjusting the parameters of the petroleum additive to the values specified in claim 1 by selecting the composition of the petroleum additive via mixing the required amount of heavy petroleum residue processing products with different parameter values.

21. The method according to claim 20, wherein the mixing of heavy petroleum residue processing products is carried out during the process of grinding the blend.

22. The method according to any one of claims 17-21, wherein the heavy petroleum residue processing products comprise products of vacuum distillation and/or thin-film evaporation of heavy residues of advanced petroleum refining.

23. The method according to claim 16, wherein in step (a) the blend components are ground so that preferably more than 65% of particles and more preferably more than 70% of particles have the fractional composition of 3 mm or less.

24. The method according to claim 23, wherein the petroleum additive can be ground together with other blend components or separately and then mixed in geound form.

25. The method according to claim 16, wherein in step (a) the coals, the petroleum coke and the petroleum additive are mixed in the following ratio of components, wt.%:

- the caking coals from 5.0 to 22.0,

- the coke coals from 5.0 to 20.5,

- the lean coals from 37.5 to 65,

- the petroleum coke from 5.0 to 15.0,

- the petroleum additive from 1.0 to 25.0.

26. A metallurgical coke produced from a blend comprising the petroleum additive according to claim 1, wherein the sulfur content does not exceed 5%, CRI does not exceed 40%, and CSR is at least 40%.