JPH10296078A - Method for manufacturing active coke with high strength and high adsorptive activity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength and the adsorptive performance by mixing fine coke dust with a specified moisture with coal dust obtained by adding a specified amount of coal heavy oil with a specific viscosity to the coal dust with a specified grain size, at a specified mixing ratio, when molding a mixed coal of a double layer structure with a specified average diameter to be pressed into a raw material with a specified diameter and further, activating the raw material through carbonization at a high temperature. SOLUTION: Several different types of coal 1 are crushed using a crusher 3 and the crushed coals are loaded into a coking furnace 4 and further, are carbonized upto such a state that no gas is generated. After that, the carbonized coals are loaded into a dry cooling tower 5 and then are quenched to recover underwater a fine coke duct with a grain diameter of 200 μm and classified to set its impregnation moisture to 10-20% in a moisture impregnating tank 6. In addition, several different types of coal duct crushed to the grain diameter of 50 μm or less using the crusher 3 are mixed so that the fluidity is 2-3. Further, a coal heavy oil 2 with a viscosity of 50 cp or less at 80 deg.C is added to the coal dust at an addition rate of 10-30% for the weight of carbon, and this mixture is introduced into a kneader 7. The fine coke dust and the coal dust are kneaded by a kneader 8 at a mixing ratio of (8:2)-(6:4) to obtain the molded mixed coal of a double structure with an average diameter of 0.5-2 mm which comprises a coal sticking to a coke surface layer. Further, this molding is formed into a column with a diameter of 10-20 mm under pressure using a molding machine 9 and is activated through carbonization at a high temperature at a heading furnace 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing activated coke having high strength and high adsorption capacity as an adsorbent in a dry desulfurization and denitration process.

[0002]

2. Description of the Related Art Recently, it has become indispensable from the viewpoint of the global environment to tighten the emission limits of sulfur oxides and nitrogen oxides. Along with this, conventional desulfurization and denitration have been carried out by the wet method.However, since the by-products of gypsum and ammonium sulfate must be reprocessed, and high efficiency and avoidance of restrictions on the installation location, dry methods such as carbon and metal catalysts have been used. And it is moving to the moving bed type fluidized bed type. The moving bed type desulfurization and denitration requires a high adsorption capacity that is inconsistent with abrasion resistance and impact strength, which is incomparable to the conventional fixed bed type. This activated carbon for dry desulfurization and denitration includes JP-B-62-51.
No. 885, in which a binder is added to coke having high activity and several kinds of coal to activate carbonization after adjusting the strength, and the oxygen concentration and temperature are controlled and preliminarily carbonized in JP-A-5-105415. Japanese Patent Application Laid-Open No. 4-219308 discloses a method in which semi-coke and caking coal are added to form dry distillation, and a method in which the temperature of the formed coke is increased to bring it into contact with a sulfurous acid gas to produce activated carbon with high denitration ability, as disclosed in Japanese Patent Application Laid-Open No. 4-219308 As described in JP-A-48294, a product molded to have a constant logarithmic strength, followed by treatment with sulfuric acid or the like to form a dry coke to produce activated coke has been put to practical use or developed.

[0003]

The above-mentioned activated carbon production process has the following problems. Perform pre-treatment and increase the logger strength by 20 to 30% to increase the surface area.
Even if the optimum value is used, it is difficult to manufacture activated carbon that has a high variability of the coal itself and a logarithmic strength that expresses rotational wear, and it is difficult to manufacture activated carbon that has performance that also has adsorption capacity. Activated carbon which can avoid a decrease in adsorptivity due to crystallization or precipitation of crystalline components could not be produced. In addition, in this preliminary carbonization, volatile components and fluidity often change even within the same coal type and within the same lot, and the state after preliminary carbonization may change depending on the elapsed processing time. In each process, there were cases where the above fluctuations could not be suppressed. In addition to this, there is a method of improving the pore diameter and the area of activated carbon by adsorbing sulfur and the like.
In places where there are severe wear collisions such as fluidized beds and moving beds for a long period of time, the amount of wear increases, the required amount increases and the economic efficiency decreases, and the handling of sulfur content complicates the process, and desulfurization and denitration Sulfur is discharged in the production of raw materials for use, and thus the above method is against the current trend of harmonizing with the global environment.

[0004]

As described above, even coals of the same brand have component fluctuations such as volatile matter, fluidity, and ash, and even a single type of coal, such as an index such as log strength,
It is difficult to get into the optimal value range. Especially in Japan, which relies on foreign materials for raw materials, it is very difficult to receive coal with limited coal types and components, and continuous analysis is not possible if feedback control is performed within a certain range in the preliminary carbonization furnace. There is also a time lag in the rotational wear test such as strong logger strength, and even from the current situation where changes occur even within the same coal type lot, when considering stable and mass production, it is not a sufficient control factor, and it is always stable It is currently difficult to ensure quality.

In the present invention, a coke differential of 200 μm or less generated when coal is completely dry-distilled and rapidly cooled in a coke oven for iron making is stirred in water, and the pores of the coke powder are impregnated with water sufficiently to the inside to impregnate. 10-20% moisture
Is used as a main raw material, and as a secondary raw material, one or more types of coal pulverized to 50 microns or less so as to have a fluidity of about 2 to 3 and coal-based heavy oil ( Preferably, specific gravity is 1.15 or more), and particularly, viscosity is 8
A substance obtained by removing light components such as benzene, toluene, and xylene in advance so as to be 50 cp or less at 0 ° C. is added in an amount of about 10 to 30% based on the weight of carbon, mixed at 80 ° C. or more, and sufficiently adhered to the coal surface. . The kneaded coal powder is added to and mixed with the main raw material in a weight ratio of 20 to 40%. The mixing temperature is about 60 ° C, and the viscosity of heavy coal oil is 10
It is desirable that the temperature be 0 to 500 cp. As a result, a mixed charcoal having a two-layer structure having an average diameter of 0.5 to 2 mm in which heavy oil charcoal is adhered to the surface of the main raw material and the pores is obtained. While maintaining the two-layer structure at 60 ° C., it is charged into a molding machine, and preferably molded into a shape having an average diameter of 5 to 10 mm by an extrusion molding machine. This forming raw material is heated to a temperature range of 800 to 900 ° C., and is charged into a heating furnace capable of continuous processing such as a rotary kiln in which a nitrogen atmosphere is applied and steam is applied within a range of 1 to 2 kg / kg-forming coal. Activated coke is produced by simultaneously performing the carbonization activation treatment.

In the present invention, as described above, completely dry-distilled coke having a cold strength (at a drum index of 50 rpm) of 80% or more is rapidly cooled by a dry method, and then fused as a main raw material and an auxiliary raw material of fine powder impregnated with water. By mixing coal with a heavy oil film formed on the surface of coal with a fluidity of 2 to 3 that can be easily dispersed, the high-strength portion of the main raw material can be uniformly dispersed, contributing to the improvement of the core strength, and the surface pores The auxiliary material covers the surface layer while retaining the water content, promoting the growth of pores inside the pores at the time of carbonization activation, and promoting the cross-linking between the pores in the weak part of the surface layer, thereby improving the internal adsorption capacity and the surface layer strength. can do. In the use of semi-cooked coke by conventional preliminary dry distillation, the variation in strength at the time of carbonization activation due to the variation in volatile components affects the yield,
In the simultaneous kneading of water and oil during kneading and molding, the coke is not sufficiently adhered to both of the added cokes due to the hydrophobicity of coal and water, making it impossible to sufficiently disperse the coke, resulting in a product with uniform quality and less variation. Production was difficult,
The present invention has remarkably improved such a point.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the configuration of a manufacturing process according to the present invention. In FIG. 1, coal 1 as a raw material is pulverized by a pulverizer 3, and coal containing 85% or more having a diameter of 3 mm or less is charged into a coke oven 4. A kneader 7 for kneading with the coal-based heavy oil 2 is charged with coal powder pulverized to about 50 microns. In the pulverization, it is desirable to adjust the water content to 10% or less. The coal charged into the coke oven 4 is blended and adjusted to several or more coal types so as to exhibit cold strength. In the dry distillation, the gas is completely exhausted and then discharged out of the system, put into a dry cooling tower 5 and rapidly cooled to about 200 ° C. to generate a differential coke powder of about 200 μm, and a water impregnation tank 6 and the impregnated moisture is 10-20
The residence time is controlled to be in the range of%. In addition, coal powder pulverized to 50 microns or less by the pulverizer 3 is blended with several types of coal or more so that the fluidity is in the range of 2 to 3. 10-30
%, And the coal powder and the coal-based heavy oil 2 are introduced into the kneader 7. At that time, the viscosity of the heavy oil is set to 50 cp or less, preferably 10 cp, so that the heavy oil is sufficiently familiar and impregnated on the coal surface, and the surface is uniformly coated and the temperature is maintained so that the surface is partially impregnated with oil. While maintaining a certain residence time. The mixture kneaded in the water impregnation tank 6 and the mixture kneaded sufficiently in the kneader 7 are guided to the kneader 8, and the viscosity of the heavy oil is adjusted to 100 to 500 cp so as to easily adhere.
Heat and knead so as to be in the range of The kneaded material is formed into a cylindrical shape having a diameter of 10 to 20 mm by an extruder 9 to produce a forming material. In order to perform carbonization activation of the forming raw material, the furnace temperature of the heating furnace 10 is set in the range of 800 to 900 ° C., and in order to further form a nitrogen atmosphere, nitrogen 12 and steam 11 serving as an activation accelerator are added in an amount of 1 to 2 kg / kg−. The mixed kneaded coal is simultaneously introduced into a heating furnace in the range of the kneading coal, and the forming raw material is introduced into the heating furnace. After the reaction of the moisture in the inside is promoted and the oil is solidified, it is kept in the heating furnace 10 for about 1 hour and then discharged out of the system as a product.

The activated coke obtained by the method of the present invention has an abrasion strength of 95% or more as measured by the method described below,
_Ox adsorption is 30 mg / g or more, denitration rate in the presence of ammonium sulfate is 30% or more, and powdering rate is 0.1% or more.

[0009]

【Example】

(Example) Coke cold strength (drum index) 83
% Coke powder is mixed with bituminous coal and sub-bituminous coal so as to obtain a coke powder having a mean diameter of 150 microns and a VM of 0.6%. Was charged into the water impregnation tank 6 shown in (1), and the material whose impregnated water content became 15% was used as the main raw material. In addition, bituminous coal was blended to have a fluidity of 2.5 and pulverized to 40 microns. A coal-based pitch heated to 80 ° C. is inserted into the pulverized coal powder in a kneading machine, preferably a screw kneader, and kneaded for about 15 minutes to reduce the average diameter to 0.5 to 2 mm, preferably 10 μm or less to 0. This was used as an auxiliary material. At that time, the kneading machine 7 is kept at 80 ° C. with steam or the like.
Kept. These main raw materials and auxiliary raw materials were introduced at a weight ratio of 60:40 into a kneader 8 kept at 60 ° C., preferably a pin-type kneader having a high stirring effect.
After securing a residence time of about 10 minutes so that 40 μm or less in mm disappeared, it was inserted into a molding machine 9, preferably a disk-type pelletizer, and the molded shape was adjusted to a diameter of 9 mm and a length of 15 mm. The formed coal was placed in a nitrogen atmosphere at a temperature of 850 ° C.
The steam was led to a rotary kiln in a state of 1 kg / kg-formed coal, and was retained for about 60 minutes to produce activated coke. The obtained activated coke had a very excellent performance as an activated coke for desulfurization and denitration having a desulfurization rate of 85%, a denitration rate of 40%, a powdering rate of 0.04%, and a wear strength of 97%. The processing yield in the carbonization activation furnace was 99.7%.

The wear strength, desulfurization and denitration rate, and powdering rate were measured by the following methods. <Wear strength> 30 g of a sample having a size of 3 mm or more was charged by using a logarithmic test method measuring apparatus described in JIS-M-8801, and the rotating drum was rotated 1000 times (50 rpm). It is shown in the ratio of <Desulfurization and denitration rate> A tubular glass tube (30 mm inner diameter) test apparatus was charged with 20 g of activated coke, and the temperature was 130 ° C and the SO _x
150ppm, NO _x 200ppm, 200ppm ammonia
, Oxygen 15%, moisture 10%, and the balance nitrogen were passed through at 1000 cc / min for 6 hours.
_x, removal rate from the concentration of NO _x, the measured amount of adsorption. <Powdering rate under ammonium sulfate> Activated coke was exposed for about 2 weeks using a test gas and a test device at the time of the above-mentioned desulfurization and denitration rate measurement, and after stirring in an aqueous solution, only activated coke was passed under nitrogen flow for 400 hours.
After regenerating and heating at ° C., the weight was measured with a 3 mm sieve and calculated from the amount under the sieve. (Comparative Example) The auxiliary raw material coal used in the examples was pulverized to 1000 microns and inserted into a heating furnace at 800 ° C. and 5% oxygen.
The raw material retained for about 5 seconds is used as the main raw material, and the co-kneaded strong coking coal, soft pitch and water are used as auxiliary raw materials so that the logarithmic strength index (JIS-M-8801-1957) becomes 25%. 35% was blended with respect to the weight of the raw material. This compound was formed into a cylindrical shape having a diameter of 10 mm and a length of 15 mm using a disk pelletizer, and was then heated at 850 ° C. using a rotary kiln.
After carbonization for 30 minutes, about 2 hours in a Nichols furnace which is a vertical heating furnace
Activated coke was produced by elevating the temperature, activating steam and cooling over time. The obtained activated coke has a desulfurization rate of 75% and a denitrification rate of 3
5%, powdering rate: 0.1%, wear strength: 95%, and the treatment yield in the carbonization activation furnace was 96.0%. It can be seen that the present invention is an activated coke that can exhibit a reduced process and higher performance than the conventional method.

[0011]

According to the method of the present invention, by using a solid coke which is completely carbonized and coke as a main raw material,
Maintains the basic strength of activated coke, enables sufficient adhesion to main raw materials by sufficient coating of coal-based heavy oil and coal fines, promotes internal pores, enhances surface layer strength, and changes coal properties The flexibility of the raw material has been greatly improved, and the carbonization activation process has been simplified, and capital investment has been greatly reduced.

[Brief description of the drawings]

FIG. 1 is an activated coke production process used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Raw material 2 ... Coal heavy oil 3 ... Crusher 4 ... Coke oven 5 ... Dry cooling tower 6 ... Water impregnation tank 7 ... Kneader 8 ... Kneader 9 ... Molding machine 10 ... Heating furnace 11 ... Steam 12 ... Nitrogen 13 ... Product

Claims (1)

[Claims] 1. Coarse and pulverized several or more types of coal, inserted into a coke oven, carbonized until no gas is generated, and then rapidly cooled in a dry system to collect only fine powder of 200 microns or less in classified water. 10 impregnating water impregnating fine powder
A coal-based heavy having a viscosity of 50 cp or less at 80 ° C. to coal powder obtained by grinding several kinds of coal to a particle size of 50 μm or less so that the coal fluidity is in a range of 2 to 3. By adding 10 to 30% of the oil to the carbon weight and mixing the mixture, the hydrated coke powder and the coke powder to which the coal-based heavy oil adheres are mixed at a ratio of 8: 2 to 6: 4, 2 with coal on the surface of coke
Forming a mixed coal having a layer structure having an average diameter of 0.5 to 2 mm, forming the mixed coal into a forming raw material having a diameter of 10 to 20 mm by pressure molding, and subsequently performing high-temperature dry distillation activation. For producing activated coke having high strength and high adsorption capacity.