阅读说明：本技术 一种煤的预处理方法 (Coal pretreatment method ) 是由 马丽荣 刘泽龙 董亚军 于 2020-11-13 设计创作，主要内容包括：本发明涉及煤加氢气化技术领域,具体公开了一种煤的预处理方法。所述预处理方法通过在煤粉制备过程中添加灰分含量≤2％且主要成分为碳水化合物的物质,降低了混合物料的灰分含量,并利用该物质在加氢气化过程中的分解产物,将混合物料加氢气化后所得半焦的灰分控制在炼铁高炉喷吹所需要的范围内。本发明所述预处理方法不仅扩大了加氢气化技术中煤种的适用范围,使得具有较高灰分的煤种也可适用于加氢气化技术,还同时控制了加氢气化产物中半焦的灰分,使其可用作炼铁高炉喷吹材料,提高了半焦的附加值,也进一步提高了加氢气化技术的整体经济性能。(The invention relates to the technical field of coal hydro-gasification, and particularly discloses a coal pretreatment method. The pretreatment method reduces the ash content of the mixed material by adding a substance with the ash content of less than or equal to 2 percent and the main component of carbohydrate in the preparation process of the coal powder, and controls the ash content of the semicoke obtained after the mixed material is hydro-gasified within the range required by the blast furnace blowing of iron making by utilizing the decomposition product of the substance in the hydro-gasification process. The pretreatment method provided by the invention not only expands the application range of coal types in the hydro-gasification technology, so that the coal types with higher ash content can be also suitable for the hydro-gasification technology, but also controls the ash content of the semicoke in the hydro-gasification product, so that the semicoke can be used as an injection material of an iron-making blast furnace, the additional value of the semicoke is improved, and the overall economic performance of the hydro-gasification technology is further improved.)

1. A coal pretreatment method is characterized in that a substance with ash content less than or equal to 2% and carbohydrate as a main component is added into a coal raw material in the preparation process of pulverized coal, so that the total ash content of the obtained mixed material is less than the ash content of the coal raw material.

2. The pretreatment method according to claim 1, wherein the total ash content of the mixed material is 7% or less by adding the substance.

3. The pretreatment method according to claim 2, wherein the substance is added to unmilled coal or fine-milled coal powder.

4. The pretreatment method of claim 3, wherein the substances include, but are not limited to, starch and corn meal.

5. The pretreatment method according to any one of claims 1 to 4, wherein the ash content of the coal raw material is 3% to 25%.

6. Use of the coal pretreatment method according to any one of claims 1 to 5 for any one of:

(1) the usable range of the coal raw material is expanded;

(2) the ash content of the semicoke in the coal hydro-gasification product is reduced;

(3) the yield of methane in the coal hydro-gasification product is improved.

7. A method for reducing the content of semicoke ash in a coal hydrogasification product, which is characterized in that a coal raw material is pretreated by the coal pretreatment method according to any one of claims 1 to 5, and the obtained mixture is ground and used as a coal hydrogasification raw material to perform a hydrogasification reaction.

8. The method according to claim 7, characterized in that the reaction temperature of hydro-gasification is controlled according to the ash content of the feedstock:

when the ash content of the hydro-gasification raw material is 3% -7%, controlling the reaction temperature of hydro-gasification to be 750-820 ℃;

or when the ash content of the hydro-gasification raw material is 0.5-3%, controlling the reaction temperature of hydro-gasification to be 850-950 ℃.

9. The method of claim 7 or 8, wherein the carbon conversion of the hydro-gasification reaction is 40-60%.

10. A preparation method of an iron-making blast furnace injection material is characterized in that the coal raw material is pretreated by the coal pretreatment method of any one of claims 1 to 5, the obtained mixed material is ground and then used as a coal hydro-gasification raw material to carry out hydro-gasification reaction, and carbocoal obtained in a reaction product is the iron-making blast furnace injection material.

Technical Field

The invention relates to the technical field of coal hydro-gasification, in particular to a coal pretreatment method.

Background

The coal hydrogasification technology is a process of reacting coal powder with hydrogen to generate methane-rich gas, aromatic oil products and clean semicoke. In order to improve the overall conversion performance of gasification, the ash content of coal is generally controlled within 10%, so that the application of many high-ash coal types in the hydro-gasification technology is limited, and the application range of the hydro-gasification technology is also reduced.

In addition, the ash content of the blast furnace injection material (coal) is required to be less than or equal to 12.5 percent. When the gasified semicoke is used as an injection material of an iron-making blast furnace to improve the added value of the semicoke for utilization, the effective utilization way of the semicoke is limited due to the higher ash content of the semicoke, and the requirement of the injection material of the blast furnace is met.

Therefore, how to improve the coal type applicability of the hydro-gasification technology, so that the coal type with higher ash content is also suitable for the hydro-gasification technology, and simultaneously, the ash content of the semicoke can be controlled to be suitable for being used as an injection material of an iron-making blast furnace, so that the additional value of the semicoke is improved is a main technical problem to be solved urgently at present.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a coal pretreatment method.

In order to realize the purpose of the invention, the technical scheme of the invention is as follows:

in the first aspect, the invention provides a coal pretreatment method, wherein a substance with the ash content of less than or equal to 2% and the main component of carbohydrate is added into a coal raw material in the preparation process of pulverized coal, so that the total ash content of the obtained mixed material is less than the ash content of the coal raw material.

Preferably, the total ash content of the mixed material is less than or equal to 7 percent by adding the substances.

Preferably, the material is added to raw coal that has not been ground or coal fines that have not been finely ground.

Wherein the substance includes, but is not limited to, starch and corn flour.

The ash content of the coal raw material adopted by the invention can be 3-25%.

In a second aspect, the present invention provides the use of the aforementioned coal pretreatment process in any one of:

(1) the usable range of the coal raw material is expanded;

(2) the ash content of the semicoke in the coal hydro-gasification product is reduced;

(3) the yield of methane in the coal hydro-gasification product is improved.

The pretreatment method is utilized to pretreat the coal raw material, and the obtained mixed material is ground and used as the raw material of coal hydro-gasification to carry out hydro-gasification reaction.

Preferably, the reaction temperature of hydro-gasification is controlled according to the ash content of the feedstock:

when the ash content of the hydro-gasification raw material is 3% -7%, controlling the reaction temperature of hydro-gasification to be 750-820 ℃;

or when the ash content of the hydro-gasification raw material is 0.5-3%, controlling the reaction temperature of hydro-gasification to be 850-950 ℃.

Further, the carbon conversion rate of the hydro-gasification reaction is generally 40-60%.

The invention further provides a preparation method of the injection material of the iron-making blast furnace, which is characterized in that the pretreatment method is utilized to pretreat the coal raw material, the obtained mixed material is ground and then used as the raw material for coal hydro-gasification to carry out hydro-gasification reaction, and the carbocoal obtained from the reaction product is the injection material of the iron-making blast furnace.

Preferably, the method for reducing the content of semi-coke ash in the coal hydro-gasification product is adopted in the method for preparing the blast furnace injection material, and the reaction temperature of hydro-gasification is controlled according to the ash content of the raw material.

The percentage contents mentioned in the invention refer to the mass percentage contents unless specially stated; all the raw materials or reagents are common commercial products, and all the operations are conventional in the field unless otherwise specified.

The above-described preferred conditions may be combined with each other to obtain a specific embodiment, in accordance with common knowledge in the art.

The invention has the beneficial effects that:

the invention provides a coal pretreatment method, which is characterized in that a substance with ash content less than or equal to 2 percent and carbohydrate as a main component is added in the preparation process of coal powder to reduce the ash content of a mixed material, and the ash content of semicoke obtained after the mixed material is hydro-gasified is controlled within the range required by blast furnace injection by using the decomposition product of the substance in the hydro-gasification process.

The pretreatment method provided by the invention not only expands the application range of coal types in the hydro-gasification technology, so that the coal types with higher ash content can be also suitable for the hydro-gasification technology, but also controls the ash content of the semicoke in the hydro-gasification product, so that the semicoke can be used as an injection material of an iron-making blast furnace, the additional value of the semicoke is improved, and the overall economic performance of the hydro-gasification technology is further improved.

The method provided by the invention promotes the progress of the hydro-gasification technology, expands the energy utilization range, reduces the resource waste and has good economic and social benefits.

Detailed Description

The invention firstly provides a coal pretreatment method, and a substance with ash content less than or equal to 2% and carbohydrate as a main component is added into a coal raw material in the preparation process of pulverized coal, so that the total ash content of the obtained mixed material is less than the ash content of the coal raw material.

Further, in order to enable the semicoke ash content after coal hydro-gasification to meet the requirement of an iron-making blast furnace injection material, the total ash content of the mixed material is preferably less than or equal to 7% after the substances are preferably added according to the requirement of 40-60% of the carbon conversion rate of hydro-gasification. Therefore, the method not only can meet the requirement of coal hydro-gasification reaction on the ash content of the raw material, ensure the carbon conversion rate and the product yield of hydro-gasification, but also can ensure that the semi-coke product obtained after hydro-gasification meets the ash content requirement of the blast furnace injection material for iron making.

Wherein the substance includes, but is not limited to, starch and corn flour.

The starch is preferably starch with low ash content such as potato starch, corn starch, wheat starch, tapioca starch, etc., so that the ash content of the coal can be effectively reduced when the starch is added into the coal.

The ash content is less than or equal to 2%, the particle size of the substance with the carbohydrate as the main component is 2-100 micrometers, the particle size range of the substance meets the requirement of coal hydro-gasification on pulverized coal, and the grinding power consumption is not increased. Meanwhile, the substances (such as starch or corn flour and the like) have adsorption characteristics, and the specific surface area is 100-500 m²The water content of the coal dust can be well absorbed, the water content of the coal dust is reduced, and the drying and pneumatic conveying of the coal dust are facilitated.

Preferably, starch is added to raw coal that has not been ground or coal fines that have not been finely ground. In the specific implementation mode of the invention, the starch adding device is arranged at one side of a conveying belt before raw material coal is conveyed to the initial grinding equipment, starch is directly added on the belt for conveying the coal according to the proportion of the coal and the starch while coal powder is conveyed by the belt, a dynamic starch adding mode is adopted, the starch adding proportion is conveniently controlled, the coal and the starch entering the grinding equipment can be more conveniently and fully mixed, the problems that holes are possibly formed on the equipment and material pipelines are additionally arranged when the starch is selected to be added in the subsequent fine grinding equipment of the coal are avoided, and the adding way is simple and easy to operate.

The adding proportion of the starch is determined by calculating according to the ratio that (coal powder mass X coal powder ash content + starch mass X starch ash content)/(coal powder mass + starch mass) is less than or equal to 7%.

The ash content of the coal raw material adopted by the invention can be 3-25%. In the prior art, in order to improve the overall conversion performance of hydro-gasification, the ash content of coal is generally controlled within 10%, so that the application of a plurality of high-ash coal types in the hydro-gasification technology is limited, and the application range of the hydro-gasification technology is also reduced. The coal pretreatment method provided by the invention provides a feasible scheme for the application of high-ash coal in the hydro-gasification technology, and the usable range of hydro-gasification raw materials is expanded.

The invention also provides a method for reducing the content of semicoke ash in the coal hydro-gasification product, which is characterized in that the coal raw material is pretreated by using the pretreatment method, and the obtained mixed material is ground and used as the raw material of coal hydro-gasification for hydro-gasification reaction.

The decomposition products of substances with ash content less than or equal to 2 percent and carbohydrate as the main component in the process of isolating oxygen mainly comprise carbon, hydrocarbon, carbon-oxygen compound, water, oil and the like.

Taking starch as an example, the decomposition formula of starch in the absence of oxygen is:

(C₆H₁₀O₅)_n→H₂O+C₆H₈O+CO+CH₄+H₂+ C; wherein, C₆H₈O represents a liquid oil product.

After being mixed with coal, the starch and the coal are heated together to participate in the hydro-gasification, and the starch can be decomposed in a hydrogen atmosphere to generate water, liquid oil products, carbon monoxide, methane, hydrogen and carbon black, so that the yields of hydro-gasification product oil products and methane are improved. Particularly, in the reaction zone of hydro-gasification at the medium-high temperature of 400-900 ℃, starch mainly undergoes a carbonization reaction to generate carbon black. In the carbon black generation process, the activity is strong, the carbon black is easy to react with hydrogen to generate methane, and the yield of methane in the hydrogenation gasification product can be effectively improved. Meanwhile, the carbon black with low ash content which cannot participate in the hydrogenation reaction is mixed with the hydrogenated and gasified semicoke, so that the ash content in the semicoke is reduced.

The carbon conversion rate of the hydro-gasification reaction is generally 40-60%, so the ratio of the carbon black subjected to the hydrogenation reaction to the carbon black not subjected to the hydrogenation reaction is 4: 6-6: 4.

Meanwhile, when the method is used for hydro-gasification reaction, the hydro-gasification reaction temperature needs to be controlled according to the principle that the ash content of the coal powder participating in hydro-gasification is higher and the hydro-gasification reaction temperature is lower, for example, the ash content of coal entering the gasification reaction is higher by 3-7%, the hydro-gasification reaction temperature is generally controlled to be 750-820 ℃, so that the carbon conversion rate of gasification is reduced, more carbon is retained in the semicoke, the yield of the semicoke is improved, and the ash content of the semicoke can meet the requirement of a blast furnace injection material. If the ash content of the coal entering the gasification reaction is lower by 0.5-3%, and the hydro-gasification reaction temperature can be controlled to be higher and reach 850-950 ℃, the carbon conversion rate of hydro-gasification can be further improved while the semicoke ash content is ensured to meet the ash content requirement of the injection material of the iron-making blast furnace, and the yield of gasification products can be further improved.

The invention also provides a preparation method of the injection material of the iron-making blast furnace, which is characterized in that the coal raw material is pretreated by utilizing the pretreatment method, the obtained mixed material is ground and then is used as a raw material for coal hydro-gasification to carry out hydro-gasification reaction, and the carbocoal obtained from the reaction product is the injection material of the iron-making blast furnace.

Preferably, the method for reducing the content of semi-coke ash in the coal hydro-gasification product is adopted in the method for preparing the blast furnace injection material, and the reaction temperature of hydro-gasification is controlled according to the ash content of the raw material.

In order that the above objects, features and advantages of the present invention may be more clearly understood, a solution of the present invention will be further described below. It should be noted that the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those described herein; it is to be understood that the embodiments described in this specification are only some embodiments of the invention, and not all embodiments.

Preferred embodiments of the present invention will be described in detail with reference to the following examples. It is to be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the present invention. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of this invention.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Example 1

1. Raw materials

Raw material coal powder with ash content of 8 percent and potato starch with ash content of 0.5 percent.

2. Pretreatment method

The addition ratio of starch was determined to be 154kg of starch per 1000kg of raw pulverized coal, calculated as (pulverized coal mass × pulverized coal ash + starch mass × starch ash)/(pulverized coal mass + starch mass) — 7%.

The starch is dynamically added according to the above proportion while the coal powder is conveyed by a belt.

And finely grinding the mixed material added with the starch to obtain the raw material for the coal hydro-gasification reaction.

Example 2

1. Raw materials

The raw material coal powder with the ash content of 6 percent and the corn starch with the ash content of 0.1 percent.

2. Pretreatment method

The addition ratio of starch was determined to be 204kg of starch per 1000kg of raw pulverized coal, calculated as (pulverized coal mass × pulverized coal ash + starch mass × starch ash)/(pulverized coal mass + starch mass) — 5%.

The starch is dynamically added according to the above proportion while the coal powder is conveyed by a belt.

And finely grinding the mixed material added with the starch to obtain the raw material for the coal hydro-gasification reaction.

Example 3

1. Raw materials

The raw material coal powder with the ash content of 4 percent and the cassava starch with the ash content of 0.2 percent.

2. Pretreatment method

The addition ratio of starch was determined to be 407kg of starch per 1000kg of raw pulverized coal, calculated as (pulverized coal mass × pulverized coal ash + starch mass × starch ash)/(pulverized coal mass + starch mass) — 2.9%.

The starch is dynamically added according to the above proportion while the coal powder is conveyed by a belt.

And finely grinding the mixed material added with the starch to obtain the raw material for the coal hydro-gasification reaction.

Example 4

The raw material obtained in example 1 was used to perform a coal hydro-gasification reaction, the reaction temperature was controlled to 780 ℃ and the reaction time was 13 seconds, and the obtained product was measured at a coal charge of 1000kg, and the results were as follows:

TABLE 1

Index (I)	Carbon conversion rate%	Methane production, Nm3	Oil yield, kg	Semicoke yield, kg	Semicoke ash content%
						Numerical value	40.2	407.13	109.76	673.17	12.0

Example 5

The raw material obtained in example 2 was used to carry out a coal hydro-gasification reaction, the reaction temperature was controlled at 820 ℃ for 12 seconds, and the product obtained when the coal charge was 1000kg was measured, with the following results:

TABLE 2

Index (I)	Carbon conversion rate%	Methane production, Nm3	Oil yield, kg	Semicoke yield, kg	Semicoke ash content%
						Numerical value	46.9	566.36	93.1	633.68	9.5

Example 6

The raw material obtained in example 3 was used to carry out a coal hydro-gasification reaction, the reaction temperature was controlled at 880 ℃ for 10 seconds, and the product obtained when the amount of coal was 1000kg was measured, with the following results:

TABLE 3

Index (I)	Carbon conversion rate%	Methane production, Nm3	Oil yield, kg	Semicoke yield, kg	Semicoke ash content%
						Numerical value	57.3	854.89	68.6	497.60	8.2

The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.