JP2001294414A - Manufacturing method of activated coke having high strength and high adsorpability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of activated coke having high strength and high adsorpability and excellent desulfurization and denitration performance. SOLUTION: Coalite obtained by heating coal having above 25% volatile matter and the fluidity of <=1.0 to 400-600 deg.C at 3 to <30 deg.C/min temperature rising rate in a heating atmosphere of <5% oxygen concentration is used as a main raw material, many formed material particles are obtained by adding a coal based heavy oil material heated to 80-200 deg.C as a binder into mixed pulverized material particles, which is obtained by adding caking coal having <=25% volatile matter and the fluidity of >1.0 to the main raw material as an auxiliary raw material, and kneading and each formed material particle is carbonized and activated.

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 adsorptivity used as an adsorbent in a dry desulfurization and denitration process.

[0002]

2. Description of the Related Art Conventionally, wet methods have been the main method for removing sulfur oxides and nitrogen oxides from various exhaust gases, but dry methods do not require wastewater treatment facilities which are complicated and difficult to maintain and manage. This method has the advantage of requiring a small installation area, and is a method that is becoming popular in recent years. Conventionally, as a carbonaceous adsorbent used in the dry method, a conventional activated carbon is mainly used, and a granulated or molded product thereof has been used. In addition, there is a problem that the strength such as abrasion resistance and impact resistance is low, the abrasion is large when the adsorption and regeneration are repeatedly used, and the economic efficiency is poor.

[0003] Various studies have been carried out to solve such drawbacks of the activated carbon-based adsorbent. Coal is used as a raw material, and various binders are added thereto. The resulting mixture is formed by dry distillation and activation under specific conditions. Molding activated coke suitable for desulfurization and denitration has been developed. For example, Japanese Patent Publication No. Sho 62-51885 discloses that a semi-active coke having a high activity is produced from coal, and this is used as a main raw material, and several kinds of coal and a binder are added thereto to increase the log index to 20 to 30%. A method of carbonizing and activating after adjusting the strength has been developed. However, the log index is an index indicating strength such as abrasion resistance. Although this method can produce activated coke excellent in abrasion resistance, it cannot improve the desulfurization and denitration performance. Also, Japanese Patent Application Laid-Open
The 1-555 JP, air, nitrogen and oxygen, the oxygen concentration 5-30% in the gas, such as CO ₂ + oxygen, preferably 10 to
A method of improving the activity by oxidizing using an oxidizing gas of 21% has been developed. However, in the oxidation and activation by such a high-concentration oxidizing gas, the oxidation proceeds to the inside of the pores. Although the effect of improving the denitration performance is recognized, the strength of the obtained activated coke is reduced, and there is a problem that it cannot withstand repeated use in a moving bed type desulfurization and denitration apparatus.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems and to provide a method for producing activated coke having high strength, high adsorption capacity and excellent desulfurization and denitration performance. It is.

[0005]

Means for Solving the Problems To solve the above-mentioned problems, the method of the present invention for producing activated coke having high strength and high adsorptivity has a volatile content of more than 25% and a fluidity of 1.0 or less. The coal is heated at a heating rate of 3 to 30 ° C./min.
The main raw material is semi-coke in a heated atmosphere having an oxygen concentration of less than 5% by raising the temperature to 0 ° C. The coking coal having a volatile content of 25% or less and a fluidity of more than 1.0 is used as a secondary raw material. Is added to the mixed pulverized material particles, and a coal-based heavy oil substance heated to 80 to 200 ° C. is added as a binder and kneaded to form a large number of molded product particles, and then each of the molded product particles is carbonized and activated. It is characterized by the following. In addition, it is desirable from the viewpoint of cost reduction that the heating rate of coal for obtaining semi-coke as the main raw material is set to 6 to 20 ° C./min.
The average particle size of the mixed and crushed particles of the main raw material and the auxiliary raw material is 10
It is desirable that the thickness be 0 μm or less. Further, the processing temperature of carbonization and activation of each of the molded product particles is preferably 800 to 900 ° C. in terms of performance.

The fluidity is defined as the maximum fluidity measured by the fluidity test method described in JIS-M-8801-1993. That is, 5 g of a sample pulverized to 425 μm or less was placed in a cylindrical crucible and placed in a lead-tin alloy bath at 3 ° C. /
Heat at a heating rate of 1 min and apply a torque of 0.010 N · m. Measure the rotation speed of the stirring rod, and determine the fluidity when the movement of the stirring rod reaches the maximum as the maximum fluidity.

[0007]

FIG. 1 shows an embodiment of the present invention.
Will be described together with the process chart of the embodiment shown in FIG. In FIG.
No. 1 has a volatile content of more than 25%, a fluidity of 1.0 or less, and a particle size of 50
mm or less semi-coke coal.
Is charged into the preliminary carbonization furnace 2 and heated to 400 to 600 ° C. at a heating rate of less than 3 to 30 ° C./min and carbonized at a low temperature in a heating atmosphere having an oxygen concentration of less than 5%. 30% of the semi-coke has disappeared. This semi-coke is introduced into the pulverizer 3 as a main raw material and pulverized. At this time, a coking coal 4 having a volatile content of 25% or less and a fluidity of more than 1.0 is used as an auxiliary raw material.
Into the pulverizer 3 to be pulverized to obtain mixed and pulverized particles of the main raw material and the auxiliary raw material. Next, the mixed and crushed particles of the main raw material and the auxiliary raw material are transferred to the kneader 7, in which, in addition to the soft pitch of the coal-based heavy oil substance heated to 80 to 200 ° C. as the binder 5, If necessary, a molding aid 6 such as water is added and kneaded. The kneaded product is introduced into a molding machine 8 and formed into a large number of molded particles having a diameter of 5 to 20 φ and a length of 5 to 20 mm. Then, each of the molded particles is quantitatively transferred to a dry distillation furnace 9 such as a rotary kiln. 1 to 3 kg per 1 kg
kg of steam 10 together with nitrogen gas 11
Carbonization at a temperature of 0 to 900 ° C. and a residence time of 1 to 2 hours,
By activating, it is possible to obtain the product 12, that is, activated coke having high strength and high adsorptivity.

In the present invention, the coal used as semi-coke as a main raw material has a volatile content of more than 25% and a fluidity of 1.0 or less. The reason is that the volatile content is 25%.
Hereinafter, coal having a fluidity of more than 1.0 is expensive, and therefore, coal obtained at relatively low cost is used.
The coal is heated at a heating rate of 3 to 30 ° C./min.
The reason for raising the temperature to 600 ° C. to obtain semi-coke is that if the rate of temperature rise is less than 3 ° C./min, it is not possible to suppress the formation of graphite crystals that reduce the activity of the coal temperament. When the temperature rise rate is 30 ° C./min or more, the inside of the coke has a large pore size such as mesopores and macropores due to rapid gas generation due to rapid heating, and ammonium sulfate is generated in these pores during desulfurization and denitration. This facilitates the destruction of the powder and facilitates powdering. In addition, it is necessary to provide a large heating device. Accordingly, the heating rate is set to be less than 3 to 30 ° C./min, but desirably, the heating rate of the coal is set to be 6 to 20 ° C./min. By setting the heating rate in this range, semi-coke having a pore structure mainly composed of micropores of 20 ° or less can be obtained quickly without providing a large heating device. Further, the reason why the oxygen concentration in the heating atmosphere is set to less than 5% together with the above-mentioned heating rate is that when the oxygen concentration in the heating atmosphere is 5% or more, the oxidation proceeds to the inside of the pores. This is because the strength and wear resistance of the formed coke are reduced. Further, the heating temperature is set to 40 under the heating rate.
The reason for setting the heating temperature to 0 to 600 ° C. is that if the heating temperature is lower than 400 ° C., it is difficult to obtain a semi-coke having a high strength because the effect of improving the desulfurization and denitration ability is small and the amount of volatile components lost is small. If the temperature exceeds 600 ° C., the loss of semi-coke due to combustion increases.

[0009] In order to secure the cohesion of the activated coke, the volatile components are 25% or less and the fluidity is 1.
Although caking coal of more than 0 is used, the mixing ratio is approximately 30% caking coal to 70% semi-cooked coke. Further, in the production of the mixed and pulverized material particles of the main raw material and the auxiliary raw material, a lump of the main raw material and the auxiliary raw material may be mixed and then pulverized into mixed and pulverized material particles, or the pulverized main raw material and the auxiliary raw material may be preliminarily pulverized. The raw material and the auxiliary raw material may be mixed, but in any case, it is desirable that the mixed and crushed material particles occupy 50% or more of the particles having a particle size of 100 μm or less. It has a particle size of 10
If the particles having a size of 0 μm or less are less than 50% of the total, the binder component of the main raw material and the auxiliary raw material is unevenly distributed in the mixed and pulverized product particles, or the moldability is deteriorated and the strength of the molded product is reduced. This is because it becomes difficult to obtain activated coke having strength.

Next, about 20% by weight of a coal-based heavy oil substance such as soft pitch heated to 80 to 200 ° C. is added as a binder to the mixed and crushed material particles. If the temperature of the substance is lower than 80 ° C., the viscosity of the coal-based heavy oil increases, and the uniform mixing with the auxiliary material decreases,
As a result, the coal-based heavy oily substance is unevenly distributed in the molded product of the mixed and pulverized particles, so that the function as a binder is reduced and the strength of the activated coke is reduced. On the other hand, 200
If the temperature exceeds ℃, there is no problem in the uniform mixing during kneading, but the temperature of the molded particles also rises, and the coal-based heavy oil is too soft, causing impact during the transportation process with insufficient strength of the molded particles. This is because if they are received, they will collapse. Therefore, the temperature of coal-based heavy oil as a binder is 80 to 200 ° C.
Is appropriate.

[0011] If necessary, the mixed pulverized material particles may further include:
Water is used as a binding aid in a weight ratio of 15% to the mixed and ground particles
Knead with a kneading machine. The kneaded product was introduced into a molding machine and formed into a cylindrical shape having a diameter of 5 to 20 φ and a length of 5 to 20 mm. The molded product was quantitatively charged into a dry distillation furnace such as a rotary kiln, and 1 to 1 kg of the molded product was obtained. 3 kg of steam is mixed with nitrogen gas at a ratio of 1: 1 and blown, and 800 to 9
By activating and carbonizing at a temperature of 00 ° C. for a residence time of 1 to 2 hours, an activated coke having the desired high strength and high adsorption capacity can be obtained.

[0012] activated coke obtained by the method of this manner, the present invention is worn intensity 95% or higher, SO _x adsorption amount 30 mg / g or more, denitrification of 30% or more, less powdering rate of 0.1% with ammonium sulfate product It has a high strength and a high adsorptivity that can sufficiently withstand repeated use in a large-scale desulfurization and denitration apparatus of the moving bed type. Incidentally, logger strength, SO _x adsorption amount, the denitration rate, the measurement of the powdering ratio by ammonium sulfate product was performed by the following method.

<Logger strength> The sieve on the screen sieved at 5.66 mm was dried at 120 ° C. for 3 hours, 30 g of the sample was collected, placed in a rotating cylinder, and the rotating cylinder was rotated 1000 times (50 rpm). Was sieved at 3 mm and expressed as a percentage of the initial sample weight of the sample of 3 mm or more.

<SO_xAdsorption capacity> Dry at 120 ° C for 3 hours
425 g of the sample was filled in a container, and the activated coke packed bed was filled.
Is heated to 120 ° C._Two1000 ppm, O_Two5
%, H_TwoO 10%, remaining N _TwoGas mixture at 26Nl / min
Vent for 5 hours, SO_TwoIs adsorbed. After adsorption, N _Twogas
Is heated to 400 ° C. in an airflow of 5 Nl / min and maintained for 3 hours.
And detach. The desorbed gas was replaced with 2 liters of 3% hydrogen peroxide solution.
Collect with a twin-type absorption bottle with a tor, and write in JIS-K-O103.
Total SO absorbed by the above neutralization method_TwoAnalyze the amount and
From the analysis value, SO per 1 g of activated coke_TwoCalculate the adsorption amount,
SO_xAdsorption capacity.

<Denitration rate> Active in a 50 mm diameter cylindrical column.
100 g of coke, and heat this sample to 90 ℃
And SO_Two135 ppm, NO 160 ppm, NH_Three
450 ppm, O _Two10%, H_TwoO 10%, remaining N_TwoBlend of
The combined gas is aerated at 2 Nl / min for 20 hours. After the end of ventilation
Measure the NO concentration at the packed bed entrance side and the packed bed exit side, and calculate
From this, the denitration rate was calculated. DeNOx rate = ｛1-(NO concentration on the outflow side of the packed bed) / (inlet side of the packed bed)
NO concentration)｝ × 100

<Powderation rate due to production of ammonium sulfate> A circle having a diameter of 50 mm
A column was filled with 100 g of activated coke, and this sample was
Heated to 90 ° C._Two135 ppm, NO 160p
pm, NH_Three450 ppm, O _Two10%, H_TwoO 10%,
N remaining_TwoIs passed through the mixture gas at a rate of 2 Nl / min for 100 hours.
You. After the aeration is complete, the activated coke is extracted from the cylindrical column.
Then, it was impregnated with water in a beaker and stirred.
Filtrate through a wire gauze.
Into pellets. Activated coke pellets with N_TwoMoth
In a 5Nl / min airflow, the temperature was raised to 400 ° C and held for 3 hours.
After regenerating, sieved with 3mm sieve, 3mm or less
The weight of the active
The powdering rate by ammonium sulfate formation by dividing
I did.

[0017]

Example: Volatile content 40%, flow rate 0.2, particle size 50mm
The following lignite-based coal is introduced into an externally heated rotary kiln, and is heated to 12 ° C / min in a heating atmosphere with an oxygen concentration of 2%, and carbonized to obtain semi-coke by carbonization so that the maximum temperature of coal particles reaches 500 ° C. , This semi-coke is 100
The main raw material was pulverized so that the ratio of particles having a particle diameter of μm or less became 95%. A bituminous coal having a volatile content of 20% and a fluidity of 1.2 was crushed by a pulverizer into particles having a particle ratio of 100 μm or less of 9%.
It was pulverized to 0% to obtain an auxiliary material. To a mixture of these main raw materials and auxiliary raw materials in a weight ratio of 7: 3, 20% of soft pitch at 120 ° C. as a binder and 15% of water as a bonding aid are added, and the mixture is kneaded. The kneaded product was formed into a cylindrical shape having a diameter of 10φ and a length of 10 mm by an extruder. The molded product is guided to an externally heated rotary kiln, and the oxygen concentration is 0.8% and the amount of steam blown is 1 kg.
Maximum temperature 850 of the molded product under the atmosphere of 1 kg per
Activated coke was produced by heating at 60 ° C. and a residence time of 60 minutes, carbonizing and activating. The obtained activated coke has a logarithmic strength of 98.8% and an SO _x adsorption amount of 50 mg /
g, a denitration rate of 50%, and a powdering rate of 0.02% due to the production of ammonium sulfate, indicating that the activated coke for desulfurization and denitration had extremely excellent performance.

<Comparative Example> The lignite-based coal used in the examples was introduced into an externally heated rotary kiln, and heated in a heating atmosphere with an oxygen concentration of 10% at a rate of 35 ° C./min. The semi-coke was dry-distilled so that the ratio of particles having a particle size of 100 μm or less was 95% in the crusher 3.
And crushed to obtain the main raw material. Further, the bituminous coal used in the examples was pulverized with a pulverizer so that the ratio of particles having a particle size of 100 μm or less became 90%, and used as an auxiliary material. A mixture of these main raw materials and auxiliary raw materials at a weight ratio of 7: 3 was mixed with a soft pitch of 120 ° C.
%, 15% water was added as a binding aid, and the mixture was kneaded with a kneading machine.
m. The molded product is guided to an externally heated rotary kiln, heated at an oxygen concentration of 0.8% and in an atmosphere with a steam injection rate of 1 kg per 1 kg of the molded product, at a maximum temperature of 850 ° C. and a residence time of 60 minutes. Coke was produced. The obtained activated coke has a logger strength of 9
Although it had a performance of 6.2%, an SO _x adsorption amount of 30 mg / g, and a denitration rate of 50%, the powdering rate due to the production of ammonium sulfate was 2.2%, which was high. It can be seen that the activated coke of the present invention has a higher strength and a higher adsorptivity than conventional activated coke.

[0019]

As described above, according to the present invention, coal is heated at a specific heating rate and heated in a low-oxidizing atmosphere to obtain semi-coke as a main raw material, and this is used to specify a secondary raw material. It can be mass-produced inexpensively and easily mass-produce activated coke with high strength and high adsorption properties such as desulfurization and denitration by forming into a mixture and pulverized material with caking coal, carbonizing and activating. It is of great value.

[Brief description of the drawings]

FIG. 1 is a process chart of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coal used as semi-coke 2 Preliminary dry distillation furnace 3 Crusher 4 Caking coal 5 Binder 6 Molding aid 7 Kneader 8 Molding machine 9 Dry distillation furnace 10 Steam 11 Nitrogen gas 12 Product

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10B 53/08 B01D 53/34 132Z 57/06 F-term (Reference) 4D002 AA02 AA12 BA04 CA07 DA41 GA01 GB12 4G046 AA01 CA06 CB02 CC01 HA05 HC12 HC23 4G066 AA04B AA14D AC06D AC08A BA20 BA35 CA23 CA28 DA02 FA18 FA23 FA28 FA34 4H012 KA02 KA03 PA04

Claims (2)

[Claims] 1. Coal having a volatile content of more than 25% and a fluidity of 1.0 or less is heated to 400 to 600 ° C. at a heating rate of 3 to 30 ° C./min and heated in an atmosphere having an oxygen concentration of less than 5%. The semi-coke is used as a main raw material, and as a secondary raw material, a mixed and crushed material obtained by adding a caking coal having a volatile content of 25% or less and a fluidity of more than 1.0 to 80-200 ° C as a binder. A method for producing activated coke having high strength and high adsorptivity, characterized in that heated coal-based heavy oily substance is added and kneaded to form a large number of molded particles, and then each molded particle is carbonized and activated. . 2. The method for producing activated coke having high strength and adsorptive capacity according to claim 1, wherein particles having a particle size of 100 μm or less occupy 50% or more of the whole of the mixed and crushed material of the main material and the auxiliary material. .