CN113429992A

CN113429992A - Method for smelting coke by adding coke powder into hazardous solid waste tar residues

Info

Publication number: CN113429992A
Application number: CN202110633023.6A
Authority: CN
Inventors: 江鑫
Original assignee: Baotou Iron and Steel Group Co Ltd
Current assignee: Baotou Iron and Steel Group Co Ltd
Priority date: 2021-06-07
Filing date: 2021-06-07
Publication date: 2021-09-24

Abstract

The invention discloses a method for smelting coke by adding coke powder to hazardous solid waste tar residues, which solves the defect of the theory of coke making by adding coke powder to the waste tar residues, determines the theory of coke making by adding coke residues, defines a method using a carbon-hydrogen ratio and an active-inert ratio as core parameters in the coke making by adding coke residues, adds the coke residues and the coke powder on the premise of ensuring the coke quality, fully utilizes the coking coal blending to treat the hazardous tar residues, explores an optimal treatment mode and treatment way for the treatment of hazardous wastes, promotes the green, environment-friendly and sustainable development of the production of coking enterprises, and protects the ecological environment.

Description

Method for smelting coke by adding coke powder into hazardous solid waste tar residues

Technical Field

The invention relates to the technical field of detection, in particular to a method for smelting coke by using hazardous solid waste tar residues and adding coke powder.

Background

The coking industry plays an important role in national economy, is a main consumption user of the coal industry, and provides high-quality metallurgical coke and coking byproducts for steel, chemical industry, pharmaceutical industry and the like. About 0.18-0.22% of the tar residue is produced during the tar production process, plus the total amount of petroleum residue per year across the country is about a million tons. The tar slag is viscous and easy-to-bond waste slag generated in the coking production process, and mainly comprises coke powder, dust, coal tar and asphalt. The tar residue contains benzene, has anesthetic effect on human central nervous system, damages to human hematopoietic system, and also contains many fused ring aromatic hydrocarbon substances such as phenol, naphthalene, benzopyrene, anthracene, carbazole, etc., has high carcinogenicity, and can cause great harm to human body. In 2016, 6, 14 months, the regulation of "coal tar residues produced in the gas purification process in the gas production industry" in the book of national hazardous wastes issued by the national environmental protection ministry belongs to hazardous wastes. In recent years, with the force of national environmental protection policies, the influence of coking coal markets and the profits of coking industries, people continuously adopt technical countermeasures to blend tar residues into blended coal for coking, and good social benefits and economic benefits are obtained. The coking coke powder is a necessary product in the metallurgical coke smelting process and the transportation process, the yield of the coke powder is huge every year when the coke powder is used as a large metallurgical coke production country in China, and the coke powder is mainly used as a sintering fuel of a steel and iron combined enterprise and is added into pellets in a small amount at present.

As a world with great steel production and consumption, the metallurgical coke is a key raw material for the production of the metallurgical coke. Meanwhile, the coking coal resources in China are relatively deficient, and the precious disposable non-renewable energy is continuously exploited, so that the resource exhaustion is always continued. The coking resources are continuously researched and developed to be expanded, so that the coking resources are continuously and healthily developed, and the high-quality development of national economy is supported. The production waste is fully utilized by effective means, so that the production waste is efficiently utilized, the production environmental protection problem is solved, and the production can be promoted to improve the economic benefit of enterprises.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide a method for smelting coke by using hazardous solid waste tar residues and adding coke powder.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for smelting coke by using hazardous solid waste tar residues and adding coke powder, which comprises the following steps,

firstly, analyzing and determining a mechanism of adding coke powder into the tar residue and a coal blending theory, and determining the coking theory of adding coke powder into the tar residue as the comprehensive application of a co-carbonization principle, an interchangeability principle and a colloid layer overlapping principle;

secondly, combining with coal blending theory analysis research to determine the main functional role of the tar residue as a binder for improving the coke quality in coal blending coking, wherein the functional roles are embodied in a volume function, a binding function and a hydrogen supply function; the main function of the coke powder in coal blending and coking is a thinning agent, and the strength and the granularity of the coke are improved.

Thirdly, comprehensively analyzing the components of the tar residues, wherein the main analysis technical performance indexes comprise porosity, fixed carbon, toluene insoluble substances, quinoline insoluble substances, volatile matters, ash content, moisture content, carbon-hydrogen ratio and the like;

fourthly, comprehensively analyzing the technical quality of the coking coal, wherein the main analysis indexes comprise technical parameters such as moisture, ash content, volatile matter, sulfur content, bonding index, maximum thickness of a colloidal layer, shrinkage, Gibber fluidity, Australian expansion degree and the like;

fifthly, integrating technical performance indexes of the tar residue, the coke powder and the coking coal, determining the blending proportion of the tar residue and the coke powder, and calculating the coal activity-inertia ratio and the carbon-hydrogen ratio of the blended coal according to a tar residue blending coking theory;

and sixthly, carrying out a test based on a small coke oven test and comprehensively analyzing the coke quality index.

Compared with the prior art, the invention has the beneficial technical effects that:

the method for smelting coke by adding coke powder to the waste coke tar residues solves the theoretical defect of coke tar residue adding coking, determines the coke tar residue adding coking theory, defines a method using a carbon-hydrogen ratio and an active-inert ratio as core parameters in the coke tar residue adding coking, adds the coke tar residues and the coke powder on the premise of ensuring the coke quality, fully utilizes coking coal blending to treat the coke tar residue hazardous waste, explores an optimal treatment mode and treatment approach for the treatment of the hazardous waste, promotes the green, environment-friendly and sustainable development of the production of coking enterprises, and protects the ecological environment. The implementation of the patent technology can generate considerable economic benefit and good social benefit, and particularly has special action and significance under the economic background of the new period of the national deep propulsion of the green development concept.

Detailed Description

A method for determining the optimal blending proportion of tar residues by using multiple technical parameters of a coal blending and coking principle comprises the following steps:

sixthly, carrying out a test based on a small coke oven test and comprehensively analyzing coke quality indexes;

the present invention will be described in detail by the following specific examples, and it will be understood by those skilled in the art that the following examples are only for the understanding of the present invention and are not intended to limit the present invention.

Example (b):

1. discussion of coal blending theory and tar residue blending mechanism

The coking mechanism of coal blending coking is generally summarized into three types at present. The first is that the colloid body which is generated in the process of bituminous coal pyrolysis and has three phases of gas, solid and liquid coexists has cohesiveness, can be adhered and bonded with surrounding solid coal particles, the mechanism is called plastic coking mechanism, the second is the basic theory of rock-phase coal blending, the coking process is considered to be the action between active substances and inert substances, and the coke strength is related to the form and content of the active substances and the form and content of the inert substances. The third is the mesophase coking theory, which considers that anisotropic substance mesophase is generated in the coal pyrolysis process and is melted and solidified along with the coking process. Three coal blending principles are considered by the three coking mechanisms: namely the co-carbonization principle, the interchangeability principle and the colloidal layer overlapping principle.

The principle of overlapping the colloidal layer is that in order to ensure the uniformity of the coke structure and improve the coal caking and coking processes, the intervals of the conversion temperature intervals of the colloidal substances, in which gas, solid and liquid phases coexist, of each single coal of the coking raw materials in the pyrolysis process are overlapped with each other, and the time of the plastic intervals of the coal in the pyrolysis process is prolonged. The common tar slag is lower than coking coal in softening and melting initial temperature, so that when tar slag is added into the blended coal, the plastic interval of the blended coal can be effectively widened, the plastic interval of the blended coal and the plastic interval of the coking coal are greatly overlapped, the yield of a colloid body can be effectively increased, the surfaces of decomposed coal particles are more fully wetted and filled with gaps of the coal particles, the coke quality is ensured, and meanwhile, the tar slag is from basic components of coke powder and tar in coking production, so that the yield of coking byproducts such as coal gas, tar and other coal chemical downstream products can be improved to a certain extent.

According to the coal petrography principle and the plastic coking mechanism, the coking process is the action between active substances and inert substances. The caking capacity of the coal in the pyrolysis process of the bituminous coal is determined by the shape and the quantity of the active substances, and the strength of the coke is determined by the formation and the quantity of the inert substances, so that the active substances and the inert substances are combined in a certain ratio in the coal blending process in order to ensure the quality of the coke. The tar residue has strong caking property in a softened and molten state, so when the tar residue is added into the blended coal, the effect of the active component can be effectively enhanced, and the strength of the inert component is relatively reduced. Under the condition, weakly caking coal, non-caking coal or lean coal can be added to effectively enhance the skeleton action of the inert components and ensure the quality of coke. Therefore, the tar residues are added into the blended coal for blending and coking, on one hand, the plasticity interval of the blended coal is widened, the colloidal substance appears in advance, the colloidal substance and the inert substance are soaked and wrapped more fully, and finally the coke quality is improved. On the other hand, the tar slag and the coal have great similarity, and a colloid body can be generated in a plastic zone of the coal, namely, more colloid bodies can be generated under the same condition, so that a proper amount of weakly caking coal, non-caking coal and pure inert substances can be added into the blended coal, and the coking coal source is enlarged on the premise of ensuring the quality of coke.

The mesophase theory considers that the coking process of bituminous coal is the formation process of mesophase. According to the theory of mesophase, the addition of tar residue and coal blending for coking can generate more isotropic colloids in the early stage and then form more polymerization liquid products, so that the isotropic colloids have more collision opportunities in the same space and are easier to mutually fuse, and the viscosity of the mother liquid matrix is increased to the extent that the spheres cannot bear, so that the coke with higher degree of optical anisotropy is formed.

2. Determining the main function of tar residue in coal blending and coking

The main functions of combining the coal blending theory tar residue as a binder for improving the coke quality in coal blending coking are represented as a volume function, improving the melting effect of the binder on coal, improving the intermediate formation process, being beneficial to the rearrangement of a molecular structure and improving the flow function of the coal pyrolysis process. Secondly, the tar slag has better thermal stability and forms a large amount of stable liquid phase in the plasticity stage, thereby improving the contact among coal particles and improving the caking property. And thirdly, the tar residue has a hydrogen supply function, contains a large amount of aromatic hydrocarbon substances, mainly takes hydrocarbon as a main component, and the tar residue serving as a binder in the coal pyrolysis process provides hydrogen which can be combined with partial oxygen-containing functional groups, so that the free radicals in the pyrolysis process can be saturated, the crosslinking among low-carbon network structures is reduced to a certain extent, the cohesiveness of a system is improved, and the formation process of an intermediate phase is improved.

3. Analysis of the major Components of Tar residue

The property characteristics of the tar residue as the blending coal binder are fully understood in the blending process, and the main performance indexes are shown in table 1.

TABLE 1 Tar residue Performance index

As can be seen from Table 1, the tar residue contains a large amount of fixed carbon and volatile polycyclic aromatic hydrocarbons, which can be decomposed into CO2 and H2O by combustion at high temperature. The tar residue is used as a binder and added into the coking coal, so that the number of the colloids in the cracking and melting process of the coking coal can be increased, the coking coal with weak caking property and non-caking property in the coal blending can be properly increased, the aim of expanding the coking coal source is fulfilled, and the hazardous waste is comprehensively utilized to be beneficial to environmental protection.

4. Feasibility analysis of the test

According to the characteristics of the tar residues, in the pyrolysis process of coking, because the volatile matter of the coke powder is low, the basic form is not changed during pyrolysis, the generated liquid can be converted into a colloidal state, but the tar residues can form a large amount of gas and colloidal substances in the process, so that the solid substances with larger molecular weight are surrounded to form the colloidal substances with coexisting gas, liquid and solid phases, and the defect of no caking property of the coke powder is counteracted. In the process of forming the semi-coke, the outer surface of the liquid-phase membrane begins to solidify, the middle part of the liquid-phase membrane is still provided with the colloid, the inner part of the liquid-phase membrane is the unchanged mixture of the lean coal and the colloid, the mixture flows out after the semi-coke shell cracks, the colloid is solidified again to form a new semi-coke layer, and finally the semi-coke layer is converted into the semi-coke. In the semicoke shrinkage process, the volatile components of the tar residues are high, the shrinkage is relatively large, the volatile components of the lean coal are low, the number of the colloidal substances is very small, the semicoke shrinkage process is mild, and the shrinkage is very low, so that in the coal blending coking process, the coke powder and the tar residues can mutually make up for the defects in each coking process, and the influence on the coke strength is greatly reduced. Therefore, when blending coal for coking, proper amount of tar residue and coke powder is feasible. The coke residue is added for coking by fully considering (1) the function of coke powder as a thinning agent so as to ensure that the active components and the inert components in the coking process have proper proportion and have the optimal active-inert ratio, thereby ensuring the lumpiness of the coke and the sufficient mechanical strength and thermal strength of the coke. (2) The addition proportion of the tar residue is proper, so that not only is the binder fully exerted, but also the excessive quantity of the colloidal substances and coal particles dilution in the cracking process of the coking coal are prevented, and the addition proportion is not proper because the softening and decomposition temperature of the tar residue is lower and the colloidal substances are thinner.

5. Procedure of test protocol

The test adopts a method of continuously adjusting different property types of the coal blending and the blending proportion of the tar residue and the coke powder, and verifying the coke quality by using a 40Kg test coke oven to determine the optimal coal blending technical scheme and the optimal tar residue blending proportion.

5.1 Properties of blending Single coal

The blended single coal is analyzed according to the category of coking coal and the performance index is detected and analyzed. The specific performance index is shown in Table 2.

TABLE 2 Single coal Performance index

TABLE 3 Gieseler fluidity index of single coal

5.2 coal blending technical scheme

After the main coking coal type is determined, the blending proportion of the tar residue is determined to be 2-6% according to the performance index of single coking coal and the performance of the tar residue, particularly the carbon-hydrogen ratio of the tar residue, the active-inert ratio of each single coal and the index of Gieseler fluidity, and the addition gradient is determined to be 1%. Different technical solutions were determined and are shown in table 4.

TABLE 4 technical scheme for distributing tar residue and blending coal

5.3 analysis of the Coke oven coking technique of the test coke oven

The coke oven is tested by using a 40Kg test coke oven, and the technical performance indexes are shown in Table 5 when the coke is smelted according to the technical scheme.

TABLE 5 coke Performance index of the samples

	A_d	V_daf	S_t,d	M40	M10	CRI	CSR	＞60mm
									Scheme 1	12.87	1.24	0.92	82.12	9.78	31.28	51.64	15.76
Scheme 2	12.81	1.31	0.93	85.62	9.27	29.84	53.21	18.94
									Scheme 3	12.78	1.29	0.92	86.14	8.87	28.78	54.34	19.32
Scheme 4	12.64	1.32	0.96	81.78	10.57	29.58	53.78	16.27
									Scheme 5	12.72	1.38	0.94	83.14	10.06	31.89	51.04	18.28
Scheme 6	12.68	1.39	0.97	78.87	12.47	35.23	47.29	14.32
									Scheme 7	12.59	1.31	0.98	73.58	14.98	38.29	46.12	14.12

5.4 analysis of test data

As can be seen from the table, in the scheme, under the condition of stable blending and coal quality, the blending amount of the tar residue is gradually increased, the block size of the refined coke is increased along with the increase of the adding amount of the tar residue, the block size basically becomes an increasing trend, and the crushing strength of the coke is also increased. When the amount of the tar residue added reaches 4%, the abrasion resistance of the obtained coke is much reduced compared with the basic scheme. Therefore, the addition amount of the tar residue and the coke powder is not more than 4%, and is preferably controlled within a range of 3-4%.

From the microstructure analysis of the coke, it can be seen from the photo that the coke made from the tar residue has more optical structures, because the tar residue contains various organic matters such as tar, coke powder and coal powder, and the organic matters form various optical structures through carbonization. The optical structure of the coke made of the tar residues is mainly granular mosaic, flaky structure and fibrous structure, and the structures are well combined. The coke obtained by carbonizing the tar residue has a large amount of mosaic structures, on one hand, the original coke grains in the tar residue have the mosaic structures, and on the other hand, part of mesophase spherules are newly generated in the gradual carbonization process, wherein the mesophase spherules generated by molecules with high reaction capacity are solidified to form the mosaic structures when the mesophase spherules do not grow in time.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.

Claims

1. A method for smelting coke by using hazardous solid waste tar residues and adding coke powder is characterized by comprising the following steps:

secondly, combining with coal blending theory analysis research to determine the main functional role of the tar residue as a binder for improving the coke quality in coal blending coking, wherein the functional roles are embodied in a volume function, a binding function and a hydrogen supply function; the main function of the coke powder in coal blending and coking is a thinning agent, so that the strength and granularity of the coke are improved;

thirdly, comprehensively analyzing the components of the tar residues, wherein the main analysis technical performance indexes comprise porosity, fixed carbon, toluene insoluble substances, quinoline insoluble substances, volatile matters, ash content, moisture content and carbon-hydrogen ratio;

and fourthly, comprehensively analyzing the technical quality of the coking coal, wherein the main analysis indexes comprise the following technical parameters: moisture, ash content, volatile matter, sulfur content, bonding index, maximum thickness of a colloidal layer, shrinkage, Gieseler fluidity and Australian expansion degree;