JPH07278565A - Modification of tar in formed coke production process - Google Patents

Abstract

PURPOSE:To provide a process for producing formed metallurgical coke effective for improving the profitability and reducing the installation cost by directly heating briquette with a heat medium gas in a vertical shaft furnace. CONSTITUTION:Briquette formed by adding a binder to powdered coal and molding the mixture is carbonized in a vertical shaft furnace to produce formed metallurgical coke. In this process, the generated tar is modified to tar having high specific gravity by spraying the tar into the carbonization chamber and heating with a heat medium gas of 800-1000 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is generated in a process for producing a coke for metallurgy in which a coal obtained by kneading coal and a binder and pressure-molding is heated and carbonized by a heating medium gas in a vertical shaft furnace. It relates to a method for modifying tar.

[0002]

2. Description of the Related Art As a method for producing a metallurgical coke from coal, a production method using a chamber furnace type coke oven having a coal carbonization chamber and a fuel gas combustion chamber separately has been generally adopted.

However, the high temperature (about 9
There is a problem that the thermal efficiency is low because coal is indirectly heated and carbonized by discharging coke of 0 to 1,000 ° C.) to the outside and heat transferred through a wall made of silica brick. Therefore, usually, a large amount of energy of 520 to 630 Mcal per ton of coal was required for the carbonization of coal. In addition, there is concern about environmental pollution due to external leakage of by-products generated during coal carbonization and generation of dust during coal charging, and low productivity due to the batch type operation mode and a large amount of stickiness. The disadvantage is that it requires coalescence.

However, in recent years, a method for producing a forming coke for metallurgy has been developed which solves these problems, and the forming coal containing a large amount of non-fine coking coal is directly heated in a vertical shaft furnace by heating gas. A metallurgical molding coke manufacturing method has been implemented in which a metallurgical molding coke is heated and directly heated by a heating medium gas in a vertical shaft furnace to be carbonized (for example, JP-B-60-38437). Gazette).

With this method, complete sealing is possible,
In addition, it is possible to use a large amount of non-caking coal by the continuous production method and the pre-press molding of coal to produce the forming coal. By heating the charcoal, which is a process with high thermal economy, for example, a molded coke is produced using an apparatus having a configuration as shown in FIG.

[0006] Preliminarily finely pulverized coal is mixed with a binder to agglomerate to form formed coal, which is then charged into the dry distillation furnace from the formed coal charging device 1 at the upper part of the dry distillation furnace. The forming coal at the time of charging is at room temperature (10 to 30 ° C). Low temperature heat medium gas heater 1
The low temperature heating medium gas is blown into the dry distillation furnace from the tuyere 6 while heating medium gas heated to 600 to 700 ° C. in 1 is blown,
The heating medium gas heated to 800 to 1,100 ° C. by the high temperature heating medium gas heater 12 is blown into the carbonization furnace from the high temperature heating medium gas blowing tuyere 7 to heat the shaped coal, whereby the shaped coal is carbonized. Make it coke. The molded coke after dry distillation is cooled to about 100 to 150 ° C. by a cooling gas and then discharged from the molded coke discharge port 4 to the outside of the system. Tar produced during the production of molded coke is a binder during the production of molded coal,
It is also used as a raw material for manufacturing an electrode pitch or a chemical raw material.

As the kind of binder used for producing shaped coal, tar generated during carbonization, soft pitch obtained by distilling the tar, petroleum heavy oil, etc. can be used. From the viewpoint of economy, tar generated in the system or soft pitch obtained by distilling the tar is inexpensive and preferable.

However, tar generated in the forming coke manufacturing process (hereinafter, forming coke tar) is discharged to the outside of the system without passing through the high temperature atmosphere temperature as compared with the chamber furnace type coke manufacturing method, so that thermal decomposition is not possible. Since it is sufficient and has not undergone secondary decomposition and thermal polymerization, specific gravity, as shown in Table 1,
Since the fa (aromatic carbon content) and the TI (toluene-insoluble content) are low and the resin is softened, the molded coke tar cannot be a good quality binder. Since there are few heavy fractions in the molded coke tar, if the tar is distilled and the heavy fraction is extracted as soft pitch, the yield of the product tar that is taken out as a by-product to the outside of the system after soft pitch is approx. It is very small, less than 2%. Moreover,
The property of the product tar is mainly a light fraction with less heavy fraction.

[0009]

[Table 1]

Therefore, the product tar cannot be a material for a good electrode pitch.

Here, fa (aromatic carbon content) is a dictionary for technical terms on coal utilization (Fuel Association of Japan) p. 293
As shown in, the ratio of aromatic carbon Car to total carbon C that constitutes the organic component of coal (fa = Car
/ C).

[0012] In Japanese Patent Application No. 01-294793, 150-500 is obtained after the molding coke tar is discharged from the system.
A tar reforming method has been proposed, in which an oxidizing gas at 0 ° C. is blown to a molded coke tar to cause catalytic reforming to make it heavy, thereby producing a binder having excellent hot load resistance. The modified tar obtained by this method has a high performance as a binder, but the equipment cost has increased because an air blowing device for tar modification is installed outside the system.

As a technique for heating a by-product with a heating medium gas in a shaft furnace in a method for producing coke, as disclosed in Japanese Patent Laid-Open No. 59-21987,
300 ~ in the cooling zone installed at the top of the vertical shaft furnace
By making contact with the circulating gas at 500 ° C, the sensible heat of the circulating gas is used to heat the tar to improve the caking property of the tar, and the heated tar is used as a heat medium to generate sensible heat in the heat exchanger. A method of collecting is proposed. However, this method has a problem that the equipment cost increases because the tar is reformed outside the system.

In Japanese Patent Laid-Open No. 59-53590, a heavy coal-based oil of 700 to 1 is used as a technique for applying a submerged combustion method in which combustion exhaust gas is directly blown into a liquid for quenching to reform coal tar. Gas at 500 ° C and 0.1 sec-1
A method of reforming petroleum heavy oil by contacting for 20 minutes has been proposed. When this method is applied to the forming coke production process, the operating cost of the forming coke production plant is increased by about 7% due to the submerged combustion equipment cost and the running cost of the equipment.

[0015]

As described above, it has been desired to develop a method for economically modifying the low temperature carbonization tar generated in the molding coke for metallurgy.

An object of the present invention is to provide a reforming method which is excellent in the economical efficiency of tar generated in a molding coke manufacturing process.

[0017]

The feature of the present invention resides in that pulverized coal is added with a binder consisting of one kind or two or more kinds of coal tar, pitch, and petroleum heavy oil and pressurized. In the process of carbonizing the formed coal in a vertical shaft furnace to produce a molding coke for metallurgy, tar generated during carbonization of the molding coke is blown into the vertical shaft furnace to generate a heat transfer gas of 800 to 1,000 ° C. It is characterized by heating at.

Here, the heat medium gas is a coke oven gas generated when carbonized forming coke is subjected to carbonization in a vertical shaft oven.

[0019]

The operation will be described below in detail.

FIG. 1 is a view showing an example of a forming coke manufacturing process for metallurgy using a vertical shaft furnace according to the present invention. 1 is a forming charcoal charging device, 2 is a shaft furnace upper distillation distillation chamber,
3 is a shaft furnace lower cooling chamber, 4 is a forming coke discharge port,
Reference numeral 5 is a furnace top circulating gas extraction duct, 6 is a low temperature heating medium gas blowing tuyere, 7 is a high temperature heating medium gas blowing tuyere, 8 is a temperature rising gas extraction duct, 9 is a cooling gas blowing tuyere, 1
0 is a circulating gas cooler, 11 is a low temperature heat medium gas heater, 12
Is a high temperature heat medium gas heater, 13 is a tar decanter, 14
Is a tar pump, 15 is a tar intermediate tank inlet side sluice valve, 16 is a tar intermediate tank, 17 is a hydrometer, 18 is a tar tank inlet side sluice valve, 19 is a tar blowing pump, 20 is a tar tank, 21 is a tar blowing vane Each mouth is shown.

The present inventors investigated the properties of molded coke tar. As a result, as shown in Table 1, the molded coke tar had a higher specific gravity, TI and fa than those of the chamber furnace coke tar.
Is low and soft. Therefore, in order to use the above-mentioned molded coke tar as a binder or a pitch material for electrodes during the production of molded coke, it is necessary to carry out a modification treatment to make it heavy.

For this reason, the inventors of the present invention used a compact carbonization furnace capable of simulating the thermal conditions of the molding coke during carbonization, and contacted the molding coke tar with the heating medium gas in the coke layer in the carbonization furnace. Then, the properties after heat treatment were investigated. As a result, as shown in FIGS. 3, 4, and 5, as compared with the method in which the molded coke tar is not heat-treated, the specific gravity, TI and fa of the molded coke tar are increased by heat-treating the molded coke tar. 8
It has been found that when heat treatment is performed at 00 to 1,000 ° C., the molded coke tar is improved to have a specific gravity, TI and fa of tar that are almost the same as those of the chamber furnace coke tar.

That is, according to the present invention, the tar generated during the production of the forming coke in the vertical shaft furnace is blown into the heating medium gas at 800 to 1,000 ° C. in the vertical shaft furnace to produce the chamber furnace coke. It is characterized in that it is modified to a property equivalent to.

In this method, as shown in FIG. 1 by way of example, tar blowing tuyere 2 above high temperature heating medium gas blowing tuyere 7
800 ~ by blowing tar into the vertical shaft furnace from 1
Since the heat treatment is performed with the heating medium gas of 1,000 ° C., the tar can be reformed by the heat treatment at a uniform temperature.
Tar with stable properties can be obtained.

Table 2 shows an example of the components of the heating medium gas. The flow rate of the heat transfer gas is 1,700 to 3,000 per 1 t of forming coal.
Nm ³ / Hr, that is, 17 to 5 per 1 ton of tar
It is 0 Nm ³ / Hr.

[0026]

[Table 2]

The tar discharged from the tar decanter 13 contains 2 to 5 wt% of water. Therefore, the present inventors also investigated the influence of the water content on the solution loss reaction of the molding coke in the carbonization process of the molding coke production process.

In the temperature range of 800 to 1,100 ° C., oxidizing components such as H ₂ O and CO ₂ in the atmospheric gas in the carbonization furnace are used.
There is a problem that not only the yield of coke products is reduced due to the reaction between the coke in the dry distillation furnace and the coke, but also the strength of the product coke is reduced. As shown in FIG. 8, an increase in the amount of solution loss reaction of coke was observed with an increase in water content, but at a reaction temperature of 1,000 ° C. or less, the amount of solution loss reaction of coke was less than 2%, and there was no particular problem. I understood it.

Therefore, in order to suppress the solution loss reaction of the coke and prevent the decrease of the coke strength, tar is blown into the shaft furnace at a temperature of 1,000 ° C. or less to bring it into contact with the atmospheric gas. Can be modified by

Further, the present inventors have examined an operation method for obtaining tar having stable properties during the operation of a molding coke manufacturing plant. Specific gravity of tar and fa and T
As a result of investigating the relationship of I, as shown in FIGS. 6 and 7, there is a good correlation between the specific gravity of tar and fa, and the specific gravity of tar and the amount of TI component in tar.

Therefore, the present inventors have completed the present invention in which a stable tar reforming effect is obtained while measuring the specific gravity of tar with an on-line hydrometer during the operation of the molding coke manufacturing process. .

When producing molded coke coal, it is necessary to add one or more of coal tar, pitch, and heavy petroleum oil as a binder to pulverized coal.
The addition ratio of the binder is preferably 5 to 10% by weight based on the pulverized coal.

Molding charcoal is produced by pressure molding at 15 to 25 t / cm ² .

The temperature of the top of the vertical shaft furnace during carbonization is 20
The temperature of the heating medium gas blown from the low temperature tuyere blowing is 0 to 350 ° C., and the temperature of the heating medium gas blown from the high temperature gas blowing tuyere is 900 to 1,100 ° C.

In the present specification, pulverized coal is coal having a size of 3 mm or less. The blending ratio of the slightly caking coal in the pulverized coal is limited to 10 to 50% by weight in order to suppress swelling and cracking during carbonization of the molded coke and to secure the caking property. The mixing ratio of caking coal is 50 to 90% by weight.

The effects of the present invention will be described below with reference to examples.

[0037]

【Example】

(Example 1) In the conventional method, the carbonization device shown in FIG.
8 wt% of soft pitch was added to 92 wt% of pulverized coal, and the temperature and flow rate of the heat medium gas blown from low temperature heat medium gas blowing tuyere 6 were 660 ° C. and 16,200 Nm ³ / Hr. The temperature and flow rate of the heating medium gas blown from the high temperature heating medium gas blowing tuyere 7 are 900 ° C., 3,200 Nm ³ / Hr, and the furnace top temperature is 230.
Dry distillation was performed at ℃. The tar 23 obtained at this time is subjected to specific gravity separation with a tar decanter 13 to obtain a tar tank 2
Collected to 0. As a result, the properties of the tar obtained are shown in Table 1.
As shown in (4), the specific gravity, TI and fa were lower than those of the chamber furnace coke tar.

On the other hand, according to the present invention, using the apparatus shown in the schematic diagram of FIG. 1, 8 wt% of soft pitch was added to 92 wt% of pulverized coal, and the compacted coal was molded into a volume of 150 cc. The temperature and flow rate of the heating medium gas blown from the blowing tuyere 6 are 660 ° C. and 16,200 Nm ³ /
Hr, the temperature and flow rate of the heat carrier gas blown from the tuyere 7 at 900 ° C. and 3,200 Nm ³ / H
r, the furnace top temperature was set to 230 ° C., and dry distillation was performed. The tar 23 obtained at this time is fed from the tar blowing tuyere 21 using the tar blowing pump 19 to
After blown into a heat carrier gas of 1,000 ° C. at a flow rate of 1.5 m ³ / Hr for heat treatment, the mixture was fed to a tar intermediate tank, and the specific gravity was measured by an on-line hydrometer 17 to obtain a specific gravity of 1.
18 or more tars were sent to the tar tank, and the properties of the tar sampled from the tar tank were analyzed. The temperature of the heat medium gas was measured with a thermocouple.

As a result, as shown in FIG. 9, 800-1.
By heat treatment up to 000 ° C., the quality was improved to be almost equivalent to that of chamber furnace coke tar. Incidentally. At 750 ° C, tar having a specific gravity of 1.17 or more could not be stably obtained.

By the above method, the molded coke tar can be reformed at a low cost, and as a result, the manufacturing cost of the molded coke is reduced by about 7%.

[0041]

INDUSTRIAL APPLICABILITY As described above, the present invention relates to a method for reforming tar generated during the production of coke for metallurgy by contacting it with a heat medium gas in a carbonization furnace, and for obtaining stable tar. The reforming cost is reduced and the technical and economical effects of the present invention are very large.

[Brief description of drawings]

FIG. 1 is an overall flow diagram of a molded coke manufacturing process to which the present invention is applied.

FIG. 2 is an overall flow diagram of a conventional molded coke manufacturing process.

FIG. 3 is a diagram showing the relationship between the atmospheric gas temperature and the specific gravity of molded coke tar.

FIG. 4 is a view showing a relationship between an atmospheric gas temperature and a toluene insoluble matter in a molded coke tar.

FIG. 5 is a graph showing the relationship between the atmospheric gas temperature and the aromatic carbon content of molded coke tar.

FIG. 6 is a graph showing the relationship between the specific gravity of molded coke tar and the aromatic carbon content.

FIG. 7 is a diagram showing the relationship between the specific gravity of molded coke tar and the toluene insoluble content in tar.

FIG. 8 is a diagram showing the effect of the present invention, showing the effect of modifying the properties of a molded coke tar.

FIG. 9 is a diagram showing the relationship between the amount of water in atmospheric gas and the amount of solution loss reaction of coke.

[Explanation of symbols]

1 ... Forming charcoal charging device 2 ... Shaft furnace upper distillation chamber 3 ... Shaft furnace lower cooling chamber 4 ... Forming coke discharge port 5 ... Furnace top circulation gas extraction duct 6 ... Low temperature heat medium gas injection tuyere 7 ... High temperature heat medium gas Blown tuyere 8 ... Temperature rising gas extraction duct 9 ... Cooling gas blown tuyere 10 ... Circulating gas cooler 11 ... Low temperature heat medium gas heater 12 ... High temperature heat medium gas heater 13 ... Tar decanter 14 ... Tar pump 15 ... Tar Intermediate tank inlet-side sluice valve 16 ... Tar intermediate tank 17 ... Hydrometer 18 ... Tar tank inlet-side sluice valve 19 ... Tar blowing pump 20 ... Tar tank 21 ... Tar blowing tuyere 22 ... Sludge 23 ... Tar 24 ... Ansui

[Procedure amendment]

[Submission date] May 11, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012] In Japanese open flat 01-294793, JP-after discharging molded coke tar out of the system, 150-500
A tar reforming method has been proposed, in which an oxidizing gas at 0 ° C. is blown to a molded coke tar to cause catalytic reforming to make it heavy, thereby producing a binder having excellent hot load resistance. The modified tar obtained by this method has a high performance as a binder, but the equipment cost has increased because an air blowing device for tar modification is installed outside the system.

Claims (1)

[Claims] 1. A coal-metallurgical method in which a coal coal, pitch, and a binder consisting of one or more kinds of heavy petroleum oil are added to pulverized coal and pressure-molded, and the coal is pressure-distilled in a vertical shaft furnace to perform metallurgy. In a process for producing a molding coke, a tar generated during carbonization of the molding coke is blown into a vertical shaft furnace and heated with a heat medium gas of 800 to 1,000 ° C. Tar modification method.