A semi-coke and a preparation method thereof

Abstract

The application provides a kind of semi-coke and its preparation method, belongs to semi-coke production technical field, the preparation method includes: selecting coal washing with first set parameter, the first parameter includes: ash component characteristic value R, Hardgrove grindability index and specific surface area;The coal washing is broken according to the set particle size and is handled;After breaking treatment, pyrolysis treatment is carried out under the second set parameter, and semi-coke particles are obtained, the second set parameter includes: back to the stove gas / air flow ratio, coke pushing speed and dry distillation temperature.The method starts from the raw material and process used in semi-coke production, can effectively improve the porosity of semi-coke, increase the specific surface area of semi-coke, and then improve the grindability index of semi-coke.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semi-coke production, and particularly relates to semi-coke and a preparation method thereof. BACKGROUND

[0002] Under the background of strict limitation of carbon quota of steel control enterprises and continuous rise of blast furnace fuel price, reducing total carbon consumption and optimizing blast furnace fuel structure have become important means for cost reduction and benefit increase of ironmaking process. Semi-coke injection into blast furnace is an important technical means for optimizing blast furnace fuel structure and meeting carbon quota requirements.

[0003] However, during the process of using semi-coke for injection, steel enterprises find many problems such as increase of powdering energy consumption, serious pipeline wear, and decrease of economic and technical indexes of blast furnace. The reason is that the existing low-temperature dry distillation process semi-coke has the disadvantage of poor grindability (HGI is generally 40-52) compared with traditional injection coal. SUMMARY

[0004] Embodiments of the present application provide a semi-coke and a preparation method thereof, to solve the technical problem of poor grindability of semi-coke prepared by the existing process.

[0005] In a first aspect, embodiments of the present application provide a preparation method of semi-coke, and the preparation method comprises:

[0006] selecting washed coal with first set parameters, wherein the first parameters comprise: ash component characteristic value R, Hardgrove grindability index, and specific surface area;

[0007] crushing the washed coal according to a set particle size;

[0008] performing pyrolysis treatment on the crushed washed coal under second set parameters to obtain semi-coke particles, wherein the second set parameters comprise: blast furnace gas / air flow ratio, coke pushing speed, and dry distillation temperature.

[0009] Further, the ash component characteristic value R of the washed coal is 0.60-1.10, the Hardgrove grindability index of the washed coal is 55-64, and the specific surface area of the washed coal is not less than 3.5 m 2 / g.

[0010] Further, the ash component characteristic value R of the washed coal is obtained through expression 1.

[0011] Expression 1:

[0012] wherein, SiO2 content in ash, Al2O3 content in ash, m CaO CaO content in ash, Fe2O3 content in ash.

[0013] Further, the dry basis volatile matter of the washed coal is not less than 33%, and the dry basis hydrogen element content of the washed coal is not less than 4.2%.

[0014] Further, the set particle size of the washed coal is 10-50mm.

[0015] Further, the gas / air flow ratio of the return is 1.82-2.23.

[0016] Further, the pushing speed is 520-740r / min.

[0017] Further, the dry distillation temperature is 630-660℃.

[0018] Further, the method further comprises screening the semicoke particles, and the screening particle size is 0-12mm.

[0019] In a second aspect, the embodiment of the present application provides a semicoke, which is prepared by the preparation method of the semicoke according to the first aspect.

[0020] Compared with the prior art, the above technical solution provided by the embodiment of the present application has the following advantages:

[0021] The embodiment of the present application provides a preparation method of semicoke, selects washed coal with specific components by specific gray component characteristic value R, breaks the washed coal to a set particle size by specific Hardgrove grindability index, selects washed coal with loose structure by specific specific surface area, and thus prepares semicoke with loose structure, necessary gray components and high specific surface area by selecting raw materials with specific components, loose structure and abundant pores; controls the surface burning loss of particles by specific gas / air flow ratio of the return, reduces the thermal polycondensation reaction in the pyrolysis process by specific pushing speed, inhibits the development of carbon chemical structure ordering and reduces the microscopic irregularity of particles, and improves the porosity of semicoke and increases the specific surface area of semicoke by specific dry distillation temperature. Therefore, the method can effectively improve the porosity of semicoke and increase the specific surface area of semicoke, and thus improve the grindability index of semicoke. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and serve to explain the principles of the present application together with the specification.

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced here. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0024] Figure 1 A flowchart of a preparation method of semi-coke provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0025] The advantages and various effects of the present application will be more clearly presented by the following specific embodiments and examples. Those skilled in the art should understand that these specific embodiments and examples are used to illustrate the present application, rather than limit the present application.

[0026] Throughout the specification, unless otherwise specifically indicated, the terms used herein are to be understood as having the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. If there is a conflict, the present specification takes precedence.

[0027] Unless otherwise specifically indicated, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0028] Under the background of strict limitation of carbon quota of steel control enterprises and continuous rise of blast furnace fuel price, reducing the total amount of carbon consumption and optimizing the structure of blast furnace fuel have become important means for cost reduction and benefit increase of ironmaking process. Blast furnace injection of semi-coke is an important technical means to optimize the structure of blast furnace fuel and meet the requirements of carbon quota.

[0029] However, during the use of semi-coke in the steel enterprise, many problems such as increase of powdering energy consumption, serious pipeline wear and tear, and decline of economic and technical indicators of blast furnace were found. The reason is that the existing low-temperature dry distillation process semi-coke has the disadvantage of poor grindability (HGI is generally 40-52) compared with traditional injection coal.

[0030] The technical scheme provided by the embodiment of the present application is to solve the above technical problems, and the general idea is as follows:

[0031] In a first aspect, the embodiment of the present application provides a preparation method of semi-coke, which comprises:

[0032] Selecting washed coal with first set parameters, wherein the first parameters include ash content characteristic value R, Hardgrove grindability index and specific surface area;

[0033] Crushing the washed coal according to a set particle size;

[0034] After the crushing treatment, pyrolysis treatment is carried out under second set parameters to obtain semi-coke particles, wherein the second set parameters include the ratio of recycled coal gas to air flow, coke pushing speed and dry distillation temperature.

[0035] The embodiment of the present application provides a preparation method of semi-coke, the coal washing with specific component is selected by specific ash component characteristic value R, the coal washing is broken to a set particle size by specific Hardgrove grindability index, the coal washing with loose structure is selected by specific specific surface area, so that the semi-coke with loose structure, necessary ash component and high specific surface area is prepared by selecting raw materials with specific component, loose structure and rich porosity; the particle surface burning loss is controlled by specific recycled gas / air flow ratio, the thermal condensation reaction in the pyrolysis process is reduced by specific coke pushing speed, the development of carbon chemical structure ordering is inhibited, and the particle microscopic irregularity is reduced, and the porosity of the semi-coke is improved and the specific surface area of the semi-coke is increased by specific dry distillation temperature. Therefore, the method can effectively improve the porosity of the semi-coke, increase the specific surface area of the semi-coke, and further improve the grindability index of the semi-coke.

[0036] As an embodiment of the present application, the ash component characteristic value R of the coal washing is 0.60-1.10, the Hardgrove grindability index of the coal washing is 55-64, and the specific surface area of the coal washing is not less than 3.5 m 2 / g.

[0037] In the present application, the lower ash component characteristic value R of the coal washing can reduce the distribution number of the hard grid node structure of the semi-coke product; the Hardgrove grindability index of the coal washing is controlled to provide the semi-coke product with a more loose structure and reduce the Mohs hardness; and the larger specific surface area of the coal washing can ensure that the semi-coke product has rich porosity and crack structure. By controlling the parameters of the raw material coal washing for producing the semi-coke, the Hardgrove grindability index of the semi-coke can be effectively improved.

[0038] As an embodiment of the present application, the ash component characteristic value R of the coal washing is obtained by expression 1.

[0039] Expression 1:

[0040] wherein, SiO2 content in ash, Al2O3 content in ash, m CaO CaO content in ash, Fe2O3 content in ash.

[0041] In the present application, the clay-like substances formed by SiO2 and Al2O3 and their combinations in the coal washing will be partially transformed in the dry distillation process, and due to the high hardness and high tightness of combination with the carbon matrix, the clay-like substances play a hindering role in the semi-coke grinding process. On the contrary, CaO and Fe2O3 generally present a discrete distribution in the coal, have low hardness and loose combination with the carbon matrix, and play a promoting role in the semi-coke grinding process. The ratio R of the two kinds of actions can quantitatively judge whether the raw coal can provide necessary ash component composition for high grindability semi-coke.

[0042] As an embodiment of the present application, the dry basis volatile matter of the washed coal is not less than 33%, and the dry basis hydrogen content of the washed coal is not less than 4.2%.

[0043] In the present application, the higher volatile matter and hydrogen content of the washed coal can ensure a higher yield of coal tar in the dry distillation process.

[0044] As an embodiment of the present application, the set particle size of the washed coal is 10-50 mm.

[0045] In the present application, the 10-50 mm block material can ensure the stability of the product quality and performance of the semicoke, and reduce the difference in grindability between different particles.

[0046] As an embodiment of the present application, the ratio of the recycled gas / air flow rate is 1.82-2.23.

[0047] In the present application, by controlling the ratio of the recycled gas / air flow rate, the content of the oxidizing atmosphere in the dry distillation gas can be optimized, so that the surface burning loss of the particles is in a reasonable range, and the crushing performance of the particles and the ash content of the semicoke can be considered.

[0048] As an embodiment of the present application, the pushing speed is 520-740 r / min.

[0049] In the present application, by controlling the pushing speed, the residence time of the semicoke in the dry distillation furnace is preferably controlled, the thermal polycondensation reaction in the pyrolysis process is reduced, the mechanical strength of the semicoke is reduced, the development of the ordered structure of the carbon chemical structure is inhibited, and the degree of irregularity of the particles is reduced.

[0050] As an embodiment of the present application, the dry distillation temperature is 630-660℃.

[0051] In the present application, by controlling the dry distillation temperature, not only the porosity of the semicoke can be improved, the specific surface area of the semicoke is increased, and thus the grindability and combustion performance of the semicoke are improved, but also the secondary reaction of the tar can be inhibited, and a higher yield of coal tar in the pyrolysis process can be ensured.

[0052] As an embodiment of the present application, the semicoke particles are further screened, and the screened particle size is 0-12 mm.

[0053] In the present application, the semicoke particles with a particle size in the range of 0-12 mm not only have a higher grindability, but also have a higher fixed carbon and calorific value.

[0054] In a second aspect, the present application provides a semicoke prepared by the preparation method of the semicoke of the first aspect.

[0055] In the application, the grindability index of the semi-coke is 60-65, the problem that the semi-coke made of the pulverized coal for blast furnace injection is difficult to be ground is solved, the post-processing cost is reduced, and the applicability and stability of the semi-coke are improved.

[0056] The application will be further described in connection with specific examples. It should be understood that the examples are only used for illustrating the application but not for limiting the scope of the application. The experimental methods not specified in the following examples are generally determined according to the national standards. If there is no corresponding national standard, the general international standards, conventional conditions, or the conditions suggested by the manufacturers are used.

[0057] Example 1:

[0058] A semi-coke and a preparation method thereof, the features of which include the following steps:

[0059] (1) raw material selection: a dry distillation coal washing with ash component characteristic value R of 0.74, Hardgrove grindability index of 58, and specific surface area of 4.2 m 2 / g is selected as the raw material; wherein the ash component characteristic value R is calculated by , SiO2 content in the ash content, Al2O3 content in the ash content, m CaO CaO content in the ash content, Fe2O3 content in the ash content; (the industrial analysis results of the coal washing are shown in Table 1, and the ash component analysis results of the coal washing are shown in Table 2)

[0060] (2) semi-coke preparation: the raw material is crushed into particles with a particle size of 20 mm, and then dry distillation is performed; wherein the flow ratio of the recycled coal gas to the air entering the furnace in the burner of the dry distillation furnace is controlled to be 2.10, the coke pushing speed of the coke pushing machine is controlled to be 670 r / min, the maximum temperature of the inner wall of the dry distillation furnace is controlled to be 655 ℃, and the particles with a particle size of less than 12 mm in the screened semi-coke products are selected as the semi-coke for blast furnace injection, and the tar yield is 8.92%;

[0061] (3) semi-coke performance index: as shown in Table 3.

[0062] Table 1 Industrial analysis results of coal washing / %

[0063] M t ]]> M ad ]]> A d ]]> V daf ]]> FC ad ]]> [SA t,d ]]> [C d ]]> H d ]]> <![CDATA[N d ]]> O d ]]> 13.5 1.82 6.9 34.21 60.14 0.33 75.15 4.48 0.87 12.28

[0064] Table 2 Ash component analysis results of coal washing

[0065] SiO2 / % Al203 / % CaO / % Fe203 / % R 17.98 12.80 35.06 6.41 0.74

[0066] Table 3 Performance index of semi-coke

[0067] M t / %]]> M ad / %]]> A d / %]]> V daf / %]]> FC ad / %]]> [SA t,d / %]]> Q gr.d / kcal / kg]]> HGI 17.2 2.02 9.82 10.32 80.14 0.29 7289 60

[0068] Example 2

[0069] A green coke and a preparation method thereof, the features comprising the following steps:

[0070] (1) raw material selection: selecting a dry distillation coal washing with ash component characteristic value R of 1.00, Hardgrove grindability index of 56, specific surface area of 4.4 m 2 / g as raw material; wherein the ash component characteristic value R is calculated as follows: SiO2 content in ash, Al2O3 content in ash, m CaO CaO content in ash, Fe2O3 content in ash; (industrial analysis results of the coal washing are shown in Table 4, and ash component analysis results of the coal washing are shown in Table 5)

[0071] (2) green coke preparation: crushing the raw material into particles with a particle size of 10 mm, and then dry distillation; wherein the flow ratio of recycled coal gas to air entering the furnace in the dry distillation furnace burner is controlled to be 2.21, the coke pushing speed of the coke pushing machine is controlled to be 720 r / min, the highest temperature of the inner wall of the dry distillation furnace is controlled to be 650℃, and particles with a particle size of less than 12 mm in the screened green coke product are selected as green coke for blast furnace injection, and the tar yield is 8.74%;

[0072] (3) green coke performance index: as shown in Table 6.

[0073] Table 4 Industrial analysis results of the coal washing / %

[0074]

[0075] Table 5 Ash component analysis results of the coal washing

[0076] SiO2 / % Al203 / % CaO / % HGI CaO / % HGI CaO / % HGI CaO Fe203 / % R 19.04 18.40 32.06 5.41 1.00

[0077] Table 6 Performance index of the green coke

[0078]

[0079] Example 3

[0080] A green coke and a preparation method thereof, the features comprising the following steps:

[0081] (1) raw material selection: selecting a dry distillation coal washing with ash component characteristic value R of 1.00, Hardgrove grindability index of 56, specific surface area of 4.4 m 2 / g, dry basis volatile matter of 33%, and dry basis hydrogen content of 4.2% as raw material; wherein the ash component characteristic value R is calculated as follows: SiO2 content in ash,​​ m is the content of Al2O3 in ash, CaO m is the content of CaO in ash, m is the content of Fe2O3 in ash;

[0082] (2) Preparation of blue coal: the raw material is crushed into particles with a particle size of 50 mm, and then dry distillation is performed; wherein the flow ratio of recycled coal gas / air entering the furnace in the dry distillation furnace burner is controlled to be 2.23, the coke pushing speed of the coke pushing machine is controlled to be 740 r / min, the highest temperature of the inner side wall of the dry distillation furnace is regulated to be 630°C, and the particles with a particle size of less than 12 mm in the blue coal product are screened as blue coal for blast furnace injection, and the tar yield is 9.55%;

[0083] (3) Performance index of blue coal: the Hardgrove grindability index of blue coal is 60.

[0084] Example 4:

[0085] A kind of blue coal and its preparation method, its characteristics include the following steps:

[0086] (1) Raw material selection: select the washed coal for dry distillation with ash component characteristic value R of 1.10, Hardgrove grindability index of 64, specific surface area of 5.2 m 2 / g, dry basis volatile matter 37%, and dry basis hydrogen content 4.9%; wherein the ash component characteristic value R is calculated as , m is the content of SiO2 in ash, m is the content of Al2O3 in ash, CaO m is the content of CaO in ash, m is the content of Fe2O3 in ash;

[0087] (2) Preparation of blue coal: the raw material is crushed into particles with a particle size of 30 mm, and then dry distillation is performed; wherein the flow ratio of recycled coal gas / air entering the furnace in the dry distillation furnace burner is controlled to be 1.82, the coke pushing speed of the coke pushing machine is controlled to be 520 r / min, the highest temperature of the inner side wall of the dry distillation furnace is regulated to be 660°C, and the particles with a particle size of less than 12 mm in the blue coal product are screened as blue coal for blast furnace injection, and the tar yield is 9.08%;

[0088] (3) Performance index of blue coal: the Hardgrove grindability index of blue coal is 65.

[0089] Example 5:

[0090] A kind of blue coal and its preparation method, its characteristics include the following steps:

[0091] (1) Raw material selection: select the washed coal for dry distillation with ash component characteristic value R of 0.7, Hardgrove grindability index of 61, specific surface area of 3.8 m 2 / g, 35% of dry basis volatile matter, 4.4% of dry basis hydrogen content, as the raw material; wherein the characteristic value R of ash component is The calculation results are as follows, SiO2 content in the ash, Al2O3 content in the ash, m CaO CaO content in the ash, Fe2O3 content in the ash;

[0092] (2) Preparation of the blue coal: the raw material is crushed into particles with a particle size of 30 mm, and then dry distillation is performed; wherein the flow ratio of the recycled coal gas to the air entering the furnace in the burner of the dry distillation furnace is controlled to be 1.82, the coke pushing speed of the coke pushing machine is controlled to be 520 r / min, the maximum temperature of the inner side wall of the dry distillation furnace is controlled to be 660℃, and the particles with a particle size of less than 12 mm in the screened blue coal product are used as the blue coal for blast furnace injection, and the tar yield is 9.08%;

[0093] (3) Performance index of the blue coal: the Hardgrove grindability index of the blue coal is 63.

[0094] Comparative Example 1

[0095] In the example 1, the raw material is replaced by: using the washed coal with a characteristic value R of ash component of 1.50, a Hardgrove grindability index of 50, and a specific surface area of 3.0 m 2 / g for dry distillation as the raw material, and the rest is the same as in the example 1.

[0096] The grindability index of the blue coal prepared by the method is 44.

[0097] Comparative Example 2

[0098] In the example 1, the crushing of the raw material in step (2) is replaced by: crushing the raw material into particles with a particle size of 80 mm, and the rest is the same as in the example 1.

[0099] The grindability index of the blue coal prepared by the method is 53.

[0100] Comparative Example 3

[0101] In the example 1, the coke pushing speed control in step (2) is replaced by 400 r / min, and the rest is the same as in the example 1.

[0102] The grindability index of the blue coal prepared by the method is 46.

[0103] Comparative Example 4

[0104] In the example 1, the maximum temperature control of the inner side wall of the dry distillation furnace in step (2) is replaced by 760℃, and the rest is the same as in the example 1.

[0105] The grindability index of the blue coal prepared by the method is 53.

[0106] In summary, the embodiment of the present application provides a preparation method of semi-coke. The method first selects raw coal by determining the inorganic mineral composition of the raw coal, then adjusts the particle size of the raw coal by crushing, and further optimizes the coal coke pyrolysis conditions by adjusting the internal pyrolysis temperature and the flow rate of the hot carrier gas, so as to improve the porosity and specific surface area of the semi-coke product, finally improve the grindability of the semi-coke, ensure the high fixed carbon and calorific value of the semi-coke, and improve the applicability of the semi-coke for blast furnace injection.

[0107] When applied to surface treatment of metal products such as crystallizer copper plate, the coating composite material has the characteristics of high wear resistance, high hardness, good chemical stability at high temperature, and prolonging the service life of the crystallizer copper plate. Not only can it be applied to continuous casting crystallizer copper plate, but also can be applied to ladle, tundish, iron ladle and other high-temperature resistant industries, overcoming the problems of short service life and poor wear resistance of the crystallizer copper plate, and is expected to be widely produced and applied.

[0108] It should be understood that the endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and the values are approximate values which are understood to encompass values approximately the same as the stated values. For ranges, the endpoints are included within the range unless specifically stated otherwise. For numerical values, the endpoints are included within the range unless specifically stated otherwise. The ranges include the endpoints.

[0109] It should be noted that, in the present text, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variant thereof are intended to cover non-exclusive inclusions, so that a process, method, article, or apparatus that comprises a list of elements does not only include those elements, but also includes other elements not expressly listed, or further includes elements inherent in such process, method, article, or apparatus. In addition, the term "and / or" appearing in the present text only describes the association relationship between the associated objects, and represents that there can be three kinds of relationships, for example, A and / or B can represent the three cases of A alone, A and B together, and B alone.

[0110] The foregoing is considered as illustrative only of the principles of the application. Numerous modifications and changes will readily occur to those skilled in the art, and it is intended to embrace all such modifications and changes that fall within the scope of the application. Accordingly, the application is not to be restricted in scope to the specific embodiments disclosed herein but is to be accorded the full scope that the principles and novel features request appropriately granted.

Claims

1. A method for preparing semi-coke, characterized in that, The preparation method includes: Select washed coal with first set parameters, the first set parameters including: ash component characteristic value R, Hardgrove grindability index and specific surface area; The washed coal is crushed according to a set particle size; After crushing, the material is subjected to pyrolysis under the second set parameters to obtain semi-coke particles. The second set parameters include: the ratio of return gas to furnace air flow, the pushing speed of the coke pusher, and the dry distillation temperature. The ash content characteristic value R of the washed coal is 0.60~1.10, the Hardgrove grindability index of the washed coal is 55~64, and the specific surface area of ​​the washed coal is not less than 3.5 m². 2 / g; The ash component characteristic value R of the washed coal is obtained through expression 1; Expression 1: ; in, This refers to the SiO2 content in the ash. This refers to the Al2O3 content in the ash. This refers to the CaO content in the ash. This refers to the Fe2O3 content in the ash. The volatile matter content of the washed coal on a dry basis is not less than 33%, and the hydrogen content of the washed coal on a dry basis is not less than 4.2%. The set particle size of the washed coal is 10~50mm; The ratio of recycled gas to incoming air flow is 1.82 to 2.23; The focus pushing speed is 520~740 r / min; The distillation temperature is 630~660℃.

2. The preparation method according to claim 1, characterized in that, The method also includes screening the semi-coke particles to select particles with a size of 0-12 mm.

3. A type of semi-coke, characterized in that, The semi-coke is prepared by the preparation method described in claim 1 or 2.

Images