KR100537112B1 - Manufacturing method of adsorbent made of coal or cokes - Google Patents

Abstract

By repeatedly performing the operations of the following (1) and (2) alternately, an adsorbent is produced using coal or coke as a raw material.

(1) coal or coke is immersed in an aqueous solution of sulfuric acid,

(2) The said coal or coke or these mixtures are heat-processed in atmosphere of inert gas or weak oxidizing gas.

Description

Manufacturing method of adsorbent based on coal or coke {MANUFACTURING METHOD OF ADSORBENT MADE OF COAL OR COKES}

The present invention relates to a method for producing adsorbents at low cost or simply by using coal and coke having a small specific surface area as raw materials.

Carbon materials having a large specific surface area and strong adsorption properties are called activated carbon or activated coke. Generally, activated carbon and activated coke are produced by carbonizing carbon materials such as palm husks and coal in an inert gas atmosphere at 400 to 900 ° C, and then reactivating with water vapor or carbon dioxide at 900 to 1100 ° C. As the industrial production method (first conventional example), for example, coal is pulverized to a diameter of 1 mm or less, dried at a low temperature at 350 to 450 ° C. in a fluidized-flow drying furnace, and then molded. The method is carried out at a high temperature and dried at a temperature of C, and at a temperature of 920 to 930 C in the regeneration furnace (see, for example, "Activated Carbon Readings (Daily Industry Newspaper, 1976) page 128, Figures 4 and 10)).

However, in the first conventional example, since the carbon material is carbonized at high temperature after carbonization, the manufacturing process is complicated, and there is a disadvantage that the fuel cost required for the carbonization and reactivation process increases.

In addition, as a method of improving the nitrogen oxide removal performance of the molded activated coke after the carbonization and reactivation treatment, a sulfuric acid treatment is carried out on the molded active coke after the carbonization and reactivation treatment, and a phenolic hydroxyl group and a carboxyl group are increased on the surface of the active coke. 2 conventional example) (for example, refer to Unexamined-Japanese-Patent No. 58-122042).

In order to obtain the molded activated coke used in the second conventional example, first, a semi-active coke having high activity is produced from coal, which is used as a main raw material, and a binder is added to a mixed coal in which various kinds of coal are mixed as a secondary raw material. To form a molding raw material. Next, the logger index of the said molding material is adjusted so that it may become 20 to 30% of range, and the molded object which shape | molded the said molding material is dried at low temperature. Subsequently, the molded product is dried at high temperature and dried to obtain activated molded coke. The specific surface area of such shaped activated coke is in the range of 100 to 400 m 2 / g. In the second conventional example, sulfuric acid treatment is performed on the activated molded coke to increase active groups such as phenolic hydroxyl groups and carboxyl groups of the molded coke, thereby improving the ability to remove nitrogen oxides.

Moreover, as a manufacturing method of the desulfurization denitrification molding active coke with high nitrogen oxide removal performance, after molding and reactivation, shaping | molding activated coke is made into SO at the temperature of 100-300 degreeC, More preferably, 150-250 degreeC in dry atmosphere. _A method of performing heat treatment at a temperature of 300 to 600 ° C. under a nitrogen atmosphere after reacting with contact with ₃ gases (a third conventional example is disclosed (see, for example, JP-A 4-219308).

In order to obtain the shaping | molding activated coke used by this 3rd prior art example, pulverized coal is used as a main raw material, it adds a caking additive, shape | molds, and performs drying and activation process. As another method for obtaining the molded activated coke, firstly, coal is dried and semi-coke is used as the main raw material, and then pulverized coal is added as coal and a binder to form the secondary raw material. Next, the carbonaceous material is again dried and reactivated to obtain a porous carbonaceous material as shaped activated coke. The specific surface area of such shaped activated coke is in the range of 100 to 300 m 2 / g. In the third conventional example, the amount of oxygen-containing functional groups on the surface of the molded active coke is increased by contacting the molded active coke with SO ₃ gas, thereby greatly improving the ammonia adsorption capacity and the oxidation activity of NO.

Therefore, conventional methods for producing activated carbon and activated coke require high production cost of activated activated coke as a raw material and require processes such as dry distillation and reactivation at a high temperature. Therefore, the process is complicated and fuel costs are high. There are several problems.

On the other hand, in the method of performing sulfuric acid treatment or SO ₃ gas treatment on the molded active coke, it is possible to increase the functional group content of the surface of the molded active coke by using the molded active coke having a large specific surface area as a raw material and performing the treatment. It is for the purpose.

In order to solve the above problems, the present invention does not require a process such as carbonization and drying at a high temperature after carbonizing a carbon material, and produces an adsorbent from coal or coke that can suppress raw material costs and fuel consumption in a simple process. It is an object to provide a method.

The inventors of the present invention adsorb sulfuric acid or SO ₃ containing gas to coal or coke, and then conduct heat treatment in an atmosphere of inert gas or weak oxidizing gas, and oxidation reaction of carbon represented by the following formula (1) or formula (2) occurs. It was found that pores were formed in the coal or coke.

C + 2H ₂ SO ₄ → CO ₂ + 2SO ₂ + 2H ₂ O (1)

C + 2SO ₃ → CO ₂ + 2SO ₂ (2)

The inventors of the present application have repeatedly reviewed the above-described findings, and as a result, the process of adsorbing sulfuric acid or SO ₃ -containing gas to coal or coke and the process of heating coal or coke after adsorption are alternately repeated. It was found that the specific surface area of was increased and the formation of pores with a pore radius of 10 nm or less was promoted.

This invention is based on the said knowledge, The summary is as follows.

(1) A method for producing an adsorbent based on coal or coke, characterized in that the operations of (1) and (2) are repeated alternately.

① After immersing coal or coke or a mixture thereof in an aqueous sulfuric acid solution,

(2) Heat the coal or coke or a mixture of these in an atmosphere of inert gas or weak oxidizing gas.

(2) A method for producing an adsorbent based on coal or coke, characterized in that the operations of (1) and (2) are repeated alternately.

(1) contact coal or coke or a mixture thereof with a gas containing SO ₃ or a gas containing SO ₂ and oxygen,

(2) Heat the coal or coke or a mixture of these in an atmosphere of inert gas or weak oxidizing gas.

(3) A method for producing an adsorbent using coal or coke as a raw material, and using the flue gas desulfurization equipment of activated coke having an adsorption tower and a regeneration tower, the operations of the following operations (1) and (2) are repeated. Method of producing an adsorbent.

(1) In the adsorption tower of the above equipment, after adsorbing SO ₂ in exhaust gas to coal or coke or a mixture thereof,

(2) In the regeneration tower of the equipment, the coal or coke or a mixture thereof is heated in an inert gas or combustion exhaust gas atmosphere to remove the adsorbed SO ₂ .

(4) The above (1) to (3), wherein the coke is carbonized by adding at least one kind selected from the group consisting of an alkali metal compound, an alkaline earth metal compound and a transition metal compound to coal and coking in a coke oven. The manufacturing method of the adsorbent which used the coal or coke of any one of) as a raw material.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Examples of coal used in the present invention include lignite, bituminous coal, anthracite coal and the like. Examples of the coke used in the present invention include substances obtained by distilling coal, coal pitch or petroleum pitch, and examples thereof include blast furnace coke, casting coke, coal pitch coke and petroleum pitch coke (petroleum coke). Coke and coal may be used individually, respectively, and may mix and use several types. However, activated carbon and activated coke with an enlarged specific surface area for activating treatment are not included in the coal and coke used in the present invention. Moreover, it is preferable that the specific surface area of the coal or coke used by this invention is 0.01-10 m <2> / g. If the specific surface area is less than 0.01 m 2 / g, the formation of pores becomes difficult. If the specific surface area is more than 10 m 2 / g, the effect of sulfuric acid treatment or SO ₃ containing gas treatment is reduced.

Further, after adding at least one kind of a compound of an alkali metal, a compound of an alkaline earth metal, and a compound of a transition metal to the coal as coke, in a coke furnace, for example, at a temperature of 1100 to 1500 DEG C and a drying time of 10 to 30 hours. by using a coke obtained by dry distillation, the efficiency of the sulfate process or the SO ₃ containing process gas is remarkably improved. When the dry distillation conditions are separated from the said temperature range and time range, a process efficiency may not improve. Therefore, it is preferable to make dry conditions into the said range. In addition, it is possible to further improve the efficiency of sulfuric acid treatment or SO ₃ -containing gas treatment by mixing and using these cokes.

Here, compounds of alkali metals, compounds of alkaline earth metals and compounds of transition metals not only become nuclei when pores are formed in the treatment, but also promote the formation of pores by promoting the oxidation reaction of carbon by the catalytic action. .

Alkali metal is a general term of Li, Na, K, Rb, Cs, and Fr belonging to Group 1 of the periodic table. In addition, an alkali metal compound is hydroxide, peroxide, hydroxide, nitride, carbide, salt (for example, halide, nitrate, carbonate, sulfate, acetate, oxalate, etc.), double salt, etc. of alkali metal.

Alkaline earth metal is a generic term for Be, Mg, Ca, Sr, and Ba belonging to Group 2 of the periodic table. In addition, the compounds of alkaline earth metals include hydroxides, oxides, peroxides, hydroxides, nitrides, carbides, salts (for example, halides, nitrates, carbonates, sulfates, acetates, oxalates, etc.) of alkaline earth metals, and double salts. to be. Representative alkaline earth metal compounds include quicklime and limestone, and these are conventionally used industrially in steelmaking processes. In addition, quicklime and limestone exist as abundant resources in the natural world and are readily available at low cost.

Transition metals are incompletely filled atoms with d angles or elements that generate such cations, and elements from Groups 3 to 11 of the periodic table (Sc, Y, Ti, Zr, V, Nb, Cr, Mo , Mn, Tc, Fe, Ru, Co, Rh, Ni, Pd, Cu, Ag, etc.). In addition, transition metal compounds are transition metal hydroxides, oxides, peroxides, hydroxides, nitrides, carbides, salts (for example, halides, nitrates, carbonates, sulfates, acetates, oxalates, etc.), double salts, and the like. The mixture of the transition metal and the transition metal compound is a mixture containing one or more kinds of the transition metal and the transition metal compound, respectively. The mixture of transition metal compounds is a mixture containing two or more kinds of transition metal compounds.

Representative transition metals include iron. In the case of using an iron compound, a slurry containing low quality iron, iron oxide and iron or iron oxide can be used in consideration of reuse as a resource in the steelmaking process. These low quality resources have the advantage of being readily available and cheap.

Here, it is preferable that the compounding ratio of alkali metal, alkaline earth metal, or transition metal compound (metal compound) with respect to coal is 0.1 mass% or more and 20 mass% or less. When the blending ratio is less than 0.1% by mass, the effect is less by adding a metal compound, and when the blending ratio exceeds 20% by mass, the strength of the coke is large and lowers. Moreover, it is preferable that the particle size of a metal compound is 10 micrometers or more and 5 mm or less. When the particle size is less than 10 µm, industrial handling as powder is difficult to mix and dry into coal, and when the particle size exceeds 5 mm, dispersion in coke is insufficient, and the effect is small by adding a metal compound.

As coal or coke used for this invention, the thing whose particle diameter (diameter) was adjusted to 5-20 mm is preferable. When the particle diameter is less than 5 mm, the pressure loss becomes too large when used in the gas adsorption apparatus, while when the particle diameter exceeds 20 mm, the sufficient sulfuric acid treatment to the inside becomes difficult because the diameter is too large.

(Sulfuric acid treatment)

Next, the sulfuric acid treatment of this invention is demonstrated. In sulfuric acid treatment, coal, coke or a mixture thereof is first immersed in an aqueous sulfuric acid solution as carbonaceous material. The amount of the sulfuric acid aqueous solution may be any amount such that the carbonaceous material can be immersed, and the mass ratio of the carbonaceous material and the sulfuric acid aqueous solution is preferably 1 or more. As for the density | concentration of the said sulfuric acid aqueous solution, 1-96 mass% is preferable. If the sulfuric acid aqueous solution concentration is less than 1% by mass, the treatment time is long and not economical. If one sulfuric acid aqueous solution concentration is more than 96% by mass, the sulfuric acid concentration is too high, and coal or coke is refined.

When affinity between coal, coke or these mixtures and aqueous sulfuric acid solution is poor, it is preferable to add an appropriate amount of alcohol to the aqueous sulfuric acid solution. Specific examples of the alcohol used herein include methyl alcohol and ethyl alcohol. Moreover, as quantity to add, about 0.1-10 mass% is preferable. If the added amount is less than 0.1% by mass, the wettability between the alcohol and the carbonaceous material does not improve. If the added amount exceeds 10% by mass, the adsorption of alcohol on the surface of the carbonaceous material cannot be ignored and the amount of sulfuric acid adsorbed is lowered.

The time for immersing the carbonaceous material in the sulfuric acid aqueous solution is preferably 1 to 60 minutes. If the immersion time is less than 1 minute, sulfuric acid does not sufficiently penetrate into the carbonaceous material and the treatment is insufficient. On the other hand, when the immersion time exceeds 60 minutes, the processing time becomes long and it is not economical. As the immersion method, either a method of moving in an aqueous sulfuric acid solution or a batch method can be used. Moreover, the adsorption performance of sulfuric acid improves by using agitation and ultrasonic cleaning together as an auxiliary means.

Moreover, as for the liquid temperature range of aqueous sulfuric acid solution, 20-190 degreeC is preferable. If the liquid temperature is less than 20 ° C, the reaction rate of the sulfuric acid aqueous solution and the surface of the carbonaceous material decreases, the reaction time becomes long, and it is not economical. When liquid temperature exceeds 190 degreeC, reaction speed will go up too much and coal or coke refinement will progress.

The sulfuric acid mass ratio in the aqueous solution to the mass of coal or coke is preferably adjusted to be 0.01 to 1. If the mass ratio is less than 0.01, the reaction rate of sulfuric acid and the carbonaceous material surface is lowered, the reaction time is long, and it is not economical. When the mass ratio is over 1, the reaction rate is excessively increased, and the fineness of coal or coke proceeds.

Then, after the sulfuric acid treatment as described above, coal, coke or a mixture thereof and an aqueous sulfuric acid solution are separated and dried. Thereafter, heat treatment is performed in an atmosphere of inert gas or weakly oxidizing gas.

In the separation of coal, coke or a mixture of these and sulfuric acid aqueous solution, it is not necessary to strictly remove the sulfuric acid aqueous solution adhering to coal or coke. For this reason, for example, in a sulfuric acid treatment, coal or coke is drained out in advance (for example, in a non-corrosive basket or the like in sulfuric acid solution), soaked in an aqueous sulfuric acid solution, and taken out for each container drained after a predetermined time. It is possible to easily separate the sulfuric acid aqueous solution by the method. In addition, a forced method such as centrifugal separation is preferable from the viewpoint of controlling the amount of sulfuric acid deposition and recovering the sulfuric acid aqueous solution.

The purpose of drying is to remove the aqueous solution of sulfuric acid attached to coal or coke after separating the aqueous sulfuric acid solution. For this reason, as for drying temperature, 100-150 degreeC is preferable. If the drying temperature is less than 100 ° C., the moisture is sufficiently removed and not broken. If the drying temperature is more than 150 ° C., there is a risk of combustion due to oxidative heat storage of coal and coke. In addition, when a sulfuric acid aqueous solution is forcibly separated by a centrifugal separator etc., it is not necessary to necessarily dry.

The heat treatment is performed in an atmosphere of inert gas or weakly oxidizing gas. Nitrogen, argon, helium, etc. are mentioned as said inert gas. As the weak oxidizing gas, for example, carbon dioxide or combustion exhaust gas can be used. Carbon dioxide is used as pure gas or mixed with inert gas. However, when used in combination with an inert gas, the concentration thereof is not particularly limited. As combustion exhaust gas, the exhaust gas at the time of burning any fuel of a gaseous fuel, a liquid fuel, and a solid fuel can be used. However, in order to suppress abnormal heat generation by oxidation, it is preferable to control the oxygen concentration in combustion flue gas to 10 volume% or less.

In addition, an inert gas or a weakly oxidizing gas is continuously passed in order to remove SO ₂ released from the carbonaceous material around the carbonaceous material. In addition, the temperature during the heat treatment is preferably not more than 300 ℃ below 500 ℃ to sufficiently react with each other due to the sulfuric acid (H ₂ SO ₄₎ and carbon (C). If the temperature is lower than 300 ° C, the chemical reaction is insufficient. On the other hand, if the temperature exceeds 500 ° C., the chemical reaction takes place sufficiently, but it is not economical. In addition, it is preferable to make heating time into 1 to 8 hours. If the heating time is less than 1 hour, the chemical reaction is insufficient. On the other hand, if the heating time exceeds 8 hours, there is no problem in departure time, but it is not economical.

In the present invention, the above-described sulfuric acid treatment and heat treatment are alternately repeated one or more times to increase the specific surface area of coal, coke or a mixture thereof and to form pores, and to form pores having a predetermined diameter to form a predetermined ratio. Activated carbon or coke having a surface area can be obtained.

The number of repetitions is preferably about 3 to 20 times. More preferably, it is about 5-10 times. If the number of repetitions exceeds 20 times, it is not industrially established. If the number of repetitions is less than 3 times, the formation of pores is not sufficient. 1 shows an outline of the relationship between the number of repetitions, the specific surface area, and the average pore diameter. As the number of repetitions increases, the specific surface area increases, and the average pore diameter decreases. This shows that fine pores are increased by sulfuric acid treatment.

Coal or coke subjected to the sulfuric acid treatment and the heat treatment alternately can be suitably used as an adsorbent if the specific surface area is 50 m 2 / g or more or the average pore diameter is 0.5 to 5 nm.

(SO ₃ processing)

Next, the SO ₃ process of the present invention will be described. In the SO ₃ treatment, first, coal, coke or a mixture thereof as the carbonaceous material is exposed in an atmosphere of a gas containing SO ₃ or an atmosphere of a mixed gas containing SO ₂ and oxygen, and the gas component is adsorbed onto the carbon material. The concentration of SO ₃ gas in the SO ₃ containing gas is preferably 100 vol ppm or more. If the SO ₃ gas concentration is less than 100 vol ppm, the amount of adsorption is small and the treatment is insufficient. For the mixed gas containing SO ₃ and oxygen, the SO ₂ concentration is preferably 100 vol. Ppm to 10 vol.%, And the oxygen concentration is preferably at least 10 times the SO ₂ concentration by volume ratio. If the SO ₂ concentration is less than 100 ppm by volume, the amount of adsorption is small and the treatment is insufficient. When the SO ₂ concentration exceeds 10% by volume, the oxygen concentration inevitably becomes less than 10 times the SO ₂ concentration, and the amount of oxygen for oxidizing SO ₂ to SO ₃ is insufficient and the efficiency is lowered.

As an adsorption method, the method of distributing gas to the container filled with coal, coke, or these mixtures, and the method of enclosing gas are mentioned. At this time, since the adsorption phenomenon is exothermic, the amount of adsorption is increased at lower temperatures, and efficient treatment is performed. Therefore, it is preferable to make adsorption temperature 100-200 degreeC. When adsorption temperature is less than 100 degreeC, reaction rate falls, reaction time becomes long and it is not economical. When adsorption temperature exceeds 200 degreeC, reaction rate will go up too much and coal or coke consumption will increase.

The time of the adsorption treatment is SV (hr ^-1) and, SO ₂ or SO ₃ volume concentration (the proportion of the total gas SO ₂ or SO ₃ occupies, unit: dimensionless) multiplication of at least 30 and the processing time (hours) It is preferable to set as possible. Here, SV is a value obtained by dividing the gas volume flow rate by the treatment layer volume by the space velocity. For example, the SV 3000 hr ^-1, SO ₃ concentration was 1% by volume (volume ratio: 0.01) When the treatment time h is preferably 1 hour or more in the following formula (1).

(One)

After the SO ₃ treatment as described above, heat treatment is performed in an atmosphere of an inert gas or weakly oxidizing gas as in the case of sulfuric acid treatment.

At this time, the temperature during the heat treatment is preferably 300 ° C. or more and 500 ° C. or less in order to reduce the adsorbed SO ₃ and detach it from the carbonaceous material. If the temperature is less than 300 ° C, the reduction and removal of the adsorbed SO ₃ becomes insufficient. On the other hand, if the temperature exceeds 500 ° C., there is no problem in the departure temperature, but it is not economical. Moreover, it is preferable to make heating time into 1 to 8 hours. If the heating time is less than 1 hour, the reduction and removal of the adsorbed SO ₃ becomes insufficient. On the other hand, if the heating time exceeds 8 hours, the time is sufficient but not economical.

In the present invention, by repeating the aforementioned SO ₃ treatment and heat treatment alternately one or more times, increase in specific surface area and formation of pores of coal, coke or a mixture thereof are promoted, and pores having a predetermined diameter are formed and predetermined Activated carbon or activated coke having a specific surface area of can be obtained.

In addition, the repeating frequency is preferably about 3 to 20 times. More preferably, it is about 5-10 times. If the number of repetitions exceeds 20 times, it is not industrially established. Moreover, if the number of repetitions is less than 3, the formation of pores is not sufficient. The relationship between the number of repetitions, the specific surface area and the average pore diameter shows the same tendency as in the case of the sulfuric acid treatment as shown in FIG.

Coal or coke subjected to the SO ₃ treatment and the heat treatment alternately can be suitably used as an adsorbent if the specific surface area is 50 m 2 / g or more or the average pore diameter is 0.5 to 5 nm.

(SO ₂ treatment using activated coke flue gas desulfurization equipment)

Next, the SO ₂ treatment using the activated coke flue gas desulfurization plant of the present invention will be described. 2 shows a schematic of a typical activated coke flue gas desulfurization plant.

The activated coke flue gas desulfurization facility is provided with the adsorption tower 1 and the regeneration tower 2. In the adsorption tower 1, SO ₂ is adsorbed in the exhaust gas of 100-200 degreeC by active coke. On the other hand, in the regeneration tower ₂ , the activated coke which adsorbed SO2 is heated to 350 to 500 in an inert gas or combustion exhaust gas atmosphere. As a result, the adsorbed SO ₂ is released and the activated coke is regenerated.

Then, SO ₂ is continuously removed from the exhaust gas by circulating active coke between the adsorption tower 1 and the regeneration tower 2. The residence time of the activated coke depends on various conditions but is 20 to 100 hours in the rough adsorption tower and 2 to 10 hours in the regeneration tower.

In the present invention, coal, coke, or a mixture thereof is charged into the activated coke flue gas desulfurization plant, the flue gas desulfurization operation is performed, and SO ₂ adsorption and heat treatment are alternately repeated. As a result, SO ₂ is adsorbed to the carbonaceous material in the adsorption tower 1. Next, by heating the carbonaceous material on which SO ₂ is adsorbed in the regeneration tower 2, SO ₂ is released from the carbonaceous material and the carbonaceous material becomes an adsorbent corresponding to activated carbon or activated coke. In this way, an adsorbent corresponding to activated carbon or activated coke can be obtained. Moreover, it can be used as an adsorbent in this installation as it is.

In addition, the repetition frequency is preferably 10 or more times. More preferably, it is 15 times or more. If the number of repetitions is less than 10, the formation of pores is not sufficient. In the case of using a desulfurization facility, the adsorbent thus prepared is used in this facility as it is, so there is no particular upper limit. The relationship between the number of repetitions, the specific surface area and the average pore diameter shows the same tendency as in the case of the sulfuric acid treatment as shown in FIG.

Coal or coke subjected to SO ₂ treatment and heat treatment alternately using the flue gas desulfurization facility can be suitably used as an adsorbent if the specific surface area is 50 m 2 / g or more or the average pore diameter is 0.5 to 5 nm.

(Example)

Next, the Example of this invention is described. However, the present invention is not limited to various conditions shown in the following examples.

(Example 1)

The particle size of the coal ash (bituminous coal, anthracite coal, blast furnace coke, petroleum coke) was adjusted to 5-10 mm, it filled into the basket of 3 mm of mesh size, and immersed in 96 mass% sulfuric acid aqueous solution of 50 degreeC of liquid temperature for 1 hour. The amount of the sulfuric acid aqueous solution was used 10 times the carbonaceous material by mass ratio.

After immersion, the sulfuric acid aqueous solution and the carbonaceous material were centrifuged and heat-treated at 400 degreeC and nitrogen stream for 8 hours. Table 1 shows the relationship between the number of repetitions of sulfuric acid treatment and heat treatment and the specific surface area of the carbonaceous material. Here, the specific surface area is the BET specific surface area calculated by nitrogen adsorption isotherm.

Table 1

Sample Name Before treatment Number of iterations One 2 3 4 5 Bituminous coal 0.1 21 45 83 131 164 hard coal 1.4 15 25 40 65 92 Petroleum coke 0.04 11 19 30 50 73 Blast Furnace Coke 0.2 9 15 24 41 65

(Unit: ㎡ / g)

By performing sulfuric acid treatment and heat treatment, the specific surface area increased as compared with before treatment, and the specific surface area also increased as the number of treatments increased. Moreover, with respect to the radius of the pore, it was confirmed that the pore having a radius of several tens of nm decreased with increasing the specific surface area, and the pore having a few nm of the radius increased.

Next, using each carbonaceous material was repeated 5 times a sulfuric acid treatment and the heat treatment was subjected to the adsorption of SO _2. As the experimental conditions, SV was 1000 hr ⁻¹ , the gas temperature was 100 ° C., SO ₂ was 200 vol. Ppm, the oxygen concentration was 10 vol.%, And the balance was nitrogen. The average adsorption rate from the start of the experiment to 1 hour was 80% or more in any carbonaceous material. That is, it was confirmed that SO ₂ was adsorbed in all the carbon materials.

(Example 2)

The particle size of the carbonaceous material (bituminous coal, anthracite coal, blast furnace coke, petroleum coke) was adjusted to 5 to 10 mm and contacted with SO ₃ gas (concentration: 1% by volume, balance: nitrogen) at room temperature for 1 hour, and then 400 ° C. The heat treatment for 8 hours was performed in nitrogen stream. Table 2 shows the relationship between the number of repetitions of SO ₃ treatment and heat treatment and the specific surface area. Here, the specific surface area is also the BET specific surface area.

Table 2

Sample Name Before treatment Number of iterations One 2 3 4 5 Bituminous coal 0.1 17 42 79 128 171 hard coal 1.4 13 22 37 70 98 Petroleum coke 0.04 9 17 27 48 76 Blast Furnace Coke 0.2 6 10 20 37 70

(Unit: ㎡ / g)

By performing SO ₃ treatment and heat treatment, the specific surface area increased compared with before treatment, and the specific surface area also increased as the number of treatments increased. Moreover, with respect to the radius of the pore, it was confirmed that the pore having a radius of several tens of nm decreased with increasing the specific surface area, and the pore having a few nm of the radius increased.

Next, using each carbonaceous material was repeated five times to SO ₃ treatment, and heat treatment was subjected to the adsorption of SO _2. As the experimental conditions the SV 1000 hr ^-1, was the gas temperature at 100 ℃, 200 ppm by volume of SO _2, 10% by volume of oxygen, and the balance parts nitrogen. The average adsorption rate from the start of the experiment to 1 hour was 80% or more in any carbonaceous material. That is, it was confirmed that SO ₂ was adsorbed in all the carbon materials.

(Example 3)

An activated coke flue gas desulfurization test facility for sinter flue gas was charged with coke for blast furnace to perform flue gas desulfurization operation of SO ₂ adsorption and heat regeneration. As the adsorption conditions, the exhaust gas temperature was 120 ° C, the SO ₂ concentration was 200 vol. Ppm, the oxygen concentration was 15 vol.%, And the adsorption time was 20 hours. As heat regeneration conditions, atmosphere was made into nitrogen atmosphere, temperature was 400 degreeC, and heating time was 8 hours. Then, a part of the coke was extracted and the specific surface area was measured in the state where the number of repetitions (circulation cycles) of SO ₂ adsorption and heat regeneration was 5, 10, 15, and 20 times. Table 3 shows the relationship between the number of cycles and the specific surface area.

Table 3

Cycle count (times) 0 (before processing) 5 10 15 20 Specific surface area (㎡ / g) 0.5 15 35 93 107 Desulfurization Rate (%) 0.3 11 24 70 92

The specific surface area could be increased by carrying out the circulation treatment using the flue gas desulfurization plant. Moreover, about the radius of a pore, it was confirmed that the pore of several nm in radius tends to increase with the increase of a specific surface area.

In addition, when the adsorption experiment of SO ₂ of each carbon material was conducted, it was confirmed that the deactivation rate also improved with the increase in the number of cycles.

(Example 4)

Coking coal using a test coke oven having a furnace width of 425 mm, a furnace height of 400 mm, and a furnace length of 600 mm; The additive shown in Table 4 was added to the blended coal which is 65 mass% and back granular coal: 35 mass%. At this time, the particle size of the additive was set to 150 µm or less, and the blending ratio to the blended coal was 5 mass%. Thereafter, the coal briquettes and the additives were charged into a test coke oven at a charging density of 0.83 dry-t / m 3, the furnace was dried with 1250 ° C. and a drying time of 18.5 hours to produce test coke.

And the particle size of the produced coke was adjusted to 5-10 mm, the mesh size was filled into the basket of 3 mm, and it was immersed in 96 mass% sulfuric acid aqueous solution with a liquid temperature of 50 degreeC for 1 hour. The amount of the sulfuric acid aqueous solution was used 10 times the carbonaceous material by mass ratio.

After immersion, the sulfuric acid aqueous solution and the carbonaceous material were centrifuged and heat-treated for 8 hours in a 400 degreeC nitrogen stream. Table 4 shows the relationship between the number of repetitions of sulfuric acid treatment and heat treatment and the specific surface area of the carbonaceous material.

Table 4

Sample Name Before treatment Number of iterations One 2 3 4 5 No addition 0.2 9 15 24 41 65 Fe ₃ O ₄ 0.7 15 27 43 79 113 MnO ₂ 1.6 33 51 80 157 207 Na ₂ CO ₃ 1.3 37 59 87 174 221 Coal stone 0.8 11 18 33 60 95 MgO 5.0 25 42 69 121 153

(Unit: ㎡ / g)

By adding an alkali metal, an alkaline earth metal or a compound (metal compound) of a transition metal, the effect of increasing the specific surface area by sulfuric acid treatment was promoted.

Next, SO ₂ adsorption experiment was performed using each sample which repeated 5 times of sulfuric acid treatment and heat processing. As the experimental conditions the SV 1000 hr ^-1, was the gas temperature at 100 ℃, 200 ppm by volume of SO _2, 10% by volume of oxygen, and the balance parts nitrogen. The average adsorption rate from the start of the experiment to 1 hour was 90% or more in the coke to which the metal compound was added, relative to 80% when the metal compound was not added. That is, it was confirmed that the adsorption performance of SO ₂ is improved by the addition of the metal compound.

Industrial Applicability According to the present invention, it is possible to provide a method for producing an adsorbent using coal or coke, in which a raw material cost and fuel consumption are suppressed in a simple process without requiring a process such as drying and reactivation at a high temperature after carbonizing a carbon material. In addition, since it can be performed using an active coke flue gas desulfurization plant, industrial utility is high.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the outline | summary of the relationship of a repetition frequency, a specific surface area, and an average pore radius.

2 is a view showing an outline of a flue gas desulfurization plant using activated coke.

<Explanation of symbols for main parts of the drawings>

1: adsorption tower

2: regeneration tower

Claims (4)

delete The manufacturing method of the adsorbent which used coal or coke as a raw material characterized by repeating the operation of following (1) and (2) three times or more alternately. (1) after contacting coal or coke or a mixture thereof with a gas containing SO ₃ or a gas containing SO ₂ and oxygen, (2) The said coal or coke or these mixtures are heat-processed in atmosphere of inert gas or weak oxidizing gas. A method for producing an adsorbent using coal or coke as a raw material, and using the flue gas desulfurization facility of activated coke having an adsorption tower and a regeneration tower, the operations of (1) and (2) below are repeated 10 times or more. Or the manufacturing method of the adsorbent which used coke as raw material. (1) In the adsorption tower of the above equipment, after adsorbing SO ₂ in exhaust gas to coal or coke or a mixture thereof, (2) In the regeneration tower of the above equipment, the coal or coke or a mixture thereof is heated in an inert gas or combustion exhaust gas atmosphere to remove the adsorbed SO ₂ . 4. The coke according to claim 2 or 3, wherein the coke is coke obtained by adding at least one kind selected from the group consisting of alkali metal compounds, alkaline earth metal compounds and transition metal compounds to coal and carbonized in the coke oven. Method for producing an adsorbent based on coal or coke.