JP2988397B2 - Operating the blast furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a blast furnace, and more particularly, to a heat treatment of waste containing synthetic resin and the like, and gas generated at this time is blown as auxiliary fuel from a tuyere of the blast furnace to be used as fuel. The present invention relates to a method for operating a blast furnace.

[0002]

2. Description of the Related Art Conventionally, in a blast furnace, as an auxiliary fuel for coke, heavy oil or pulverized coal has been blown from a tuyere of the furnace to produce pig iron or the like.

In recent years, as this auxiliary fuel, synthetic resin waste (waste) such as plastic has been pulverized into granular or powdery form and injected into heavy oil, or has been directly blown into tuyeres to treat municipal waste. Technologies for effective use of resources have been developed. (Example: JP-A-7-228905, JP-B-51-33493) FIG. 3 is a conceptual diagram showing a method of operating a blast furnace using this plastic waste as an auxiliary fuel for pulverized coal. The plastic waste as a raw material is put into the receiving hopper 1, where drying is also performed to remove moisture. This receiving hopper part 1
The plastic waste supplied from is crushed in the crushing unit 2,
In the sieving section 3 in the next step, the particles are sieved to a preset particle size, and the particles having the set particle size are sent to the plastic powder supply hopper 4 and stored. Particles larger than the set particle size are returned from the sieving unit 3 to the crushing unit 2 again, and crushed again. The plastic powder stored in the supply hopper 4 is sent to the transport pipe 6 via the flow rate adjusting unit 5.

On the other hand, pulverized coal is stored in a hopper 7 for pulverized coal, and is sent to a transport pipe 6 via a flow rate adjusting unit 8. The carrier air is supplied to the carrier pipe 6 from the pneumatic pressure source 9 at a predetermined air volume and speed, and the plastic powder is mixed with the pulverized coal and the powder is distributed to each tuyere by the powder distributor 10. Then, a plurality of nozzles 13 inserted into the blast furnace air blow pipe 12 through the transfer pipe 11 are blown into the blast furnace 14 at high speed through tuyeres 15 provided in the blast furnace 14, and are burned in the combustion zone of the blast furnace. .

[0005]

In order to supply a synthetic resin to a blast furnace as an auxiliary fuel, as a pre-treatment, the synthetic resin is separated from waste and pulverized so that air can be conveyed. It is necessary to process it so that it can be blown from the mouth. For example, it is necessary to pulverize and granulate to a granular form (0.5 to 5 mm) or a powder form (less than 5 mm), and the processing requires a large-scale machine and the work is complicated.

Since the temperature of the tuyere is considerably high, the fine synthetic resin may melt and block the tuyere. In order to prevent this, it is necessary to supply at a considerably high pressure and at a high speed, and a very large supply means is required.

[0007] On the other hand, in the case of effective use of garbage such as municipal waste, the municipal garbage is generally discharged from households and offices in addition to industrial waste. However, there is a problem that it is troublesome because the synthetic resin must be selected.

Accordingly, an object of the present invention is to provide a technology in which waste containing combustible municipal waste other than plastics is subjected to heat treatment without sorting, and the gas generated at this time can be used as auxiliary fuel for a blast furnace. Is what you do.

[0009]

Means for Solving the Problems Municipal garbage is generally discharged as waste from ordinary households and offices and is mainly combustible. This combustible waste contains a wide variety of chemicals, for example, plastics that contain a lot of vinyl chloride resin and substances that contain large amounts of chlorine, such as chlorine bleach for office paper. It is mixed.

[0010] Therefore, it is impossible to heat-treat these wastes as they are and to use the combustion gas generated during the heat treatment as fuel for the blast furnace.

As a method of dechlorinating the combustion gas generated during the heat treatment, the generated gas is treated by various means.
For example, although emphasis is placed on cleaning treatment such as adsorption treatment with a filter or the like, it is difficult to completely remove it.

Therefore, the inventor of the present application has sought a treatment method in which a chlorine component is not discharged in a simple heat treatment facility, and as a result of a number of experimental investigations, the waste material reacts with the chlorine component at a predetermined temperature in a closed tank. It was found that this can be achieved by filling the tank with a heating source and filling the tank with a heating source.

[0013] As a result of the experimental investigation, when an additive which easily reacts with a chlorine component at a predetermined temperature is mixed in the waste, the chlorine component is securely fixed to the treated ash, and the gas generated during the carbonization contains the chlorine component. It was found that they were not contained, and that an alkali-based substance and / or silicate was suitable as an additive that easily reacted with a chlorine component at a predetermined temperature.

The present invention has been made based on these findings, and is intended to fill a closed tank with waste and an additive which reacts with a chlorine component at a predetermined temperature, and put the whole tank into a heating source and heat it. The waste is subjected to dry distillation, and the generated gas can be used as it is as fuel for the blast furnace.

That is, by mixing an appropriate amount (5 to 30% by weight) of an alkaline substance and / or a silicate which easily reacts with the chlorine component in the tank, the chlorine component is securely fixed to the treated ash (residue). Therefore, there is no chlorine component to be gasified, and the gas can be used as it is.

As a specific means, a chlorine-containing waste is mixed with an additive which reacts with the chlorine component, and a degassing-treated heated gas is obtained by dry distillation, and the gas is used as an auxiliary fuel. It is a method of operating a blast furnace without emitting dioxin from the blast furnace tuyeres.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual diagram for explaining a method of operating a blast furnace according to the present invention. The present invention is characterized in that a waste treatment system is applied instead of the conventional plastic waste supply system, and other blast furnaces and pulverized coal supply to the blast furnace are almost the same. The same or corresponding portions are denoted by the same reference numerals, and detailed description will be omitted.

In FIG. 1, reference numeral 20 denotes a tank, which is made of, for example, an iron-based material (preferably a magnetic material) and has an openable and closable lid 21. Reference numeral 22 denotes a heating coil, which is formed in a cylindrical or rectangular tube shape and constitutes a heating source by induction heating;
The tank 20 is inserted into the cylindrical shape of the heating coil 22. Then, the tank 20 is induction-heated by supplying AC power to the heating coil 22. 23 is an exhaust pipe with a valve, 24 is a valve, 25 is a pump, and 26 is a gas amount adjusting means.

Reference numeral 22 'denotes a heating coil provided on the bottom side of the tank 20, which is appropriately installed according to the size of the tank, the amount of waste disposal, and the like.

Reference numerals 27 and 28 denote valves, and reference numeral 29 denotes a gas storage tank.

In the heat treatment of the waste, the waste and the additive are filled in a tank, sealed with a sealing lid to shut off the outside air, and the tank is placed in a heating source (heating coil) installed in advance. Insert and supply electric power to the heating coil to heat the entire tank and subject the waste to carbonization. Then, after the heat treatment for a predetermined time, the tank is taken out of the heating source and cooled, the gas in the tank is taken out, and the residue (processed ash) in the tank is taken out.

When the gas is extracted directly from the pulverized coal hopper 7, the gas is mixed with the pulverized coal from the pulverized coal hopper 7 by closing the valve 28, opening the valves 24 and 27, and operating the pump 25 when supplying the gas directly to the blast furnace as auxiliary fuel. , A feed pipe 11, a nozzle 13, and a blast furnace air pipe 12 to supply the blast furnace 14 from the tuyere 15.

The gas may be supplied to the transfer pipe 11 through a gas supply pipe 30 shown by a two-dot chain line.

When the gas is temporarily stored in the gas storage tank 29, the valve 27 is closed, the valves 24 and 28 are opened, the pump 25 is operated, the gas is stored in the storage tank 19, and the valve is appropriately operated after the storage. (Opened 27 and 28) to supply as auxiliary fuel in the same manner as above.

The gas may be extracted from the tank by immediately removing the tank from the heating source and then cooling it, or by cooling while heating with the heating source.

It has been found that alkali- and / or silicate-based substances are suitable as additives which are mixed with waste and easily react with a chlorine component at a predetermined temperature, as described later.
In the present invention, this additive is mixed with waste and filled in a closed tank, and the entire tank is heated to subject the waste to dry distillation.

By performing the carbonization in this manner, the chlorine component is completely fixed to the treated ash (residue), and there is no chlorine component to be gasified. This gas is a flammable gas (CnH
m, etc.), it is a new fuel containing no chlorine component.

The following experimental investigation revealed that mixing of the waste in the tank with an alkaline and / or silicate additive reliably fixes the chlorine component.

In the experiment, first, the following simulated garbage that simulates standard city garbage is created.

20% by weight of plastic (PE, PP,
PS, PVDC) 50% by weight ・ Paper (tissue, newspaper, wrapping paper, box, beverage pack) 20% by weight ・ 10% by weight of cloth (waste, etc.) ・ Kitchen The simulated garbage is crushed and crushed into 8g of simulated garbage. 1 to 2 g of two kinds of powdered calcium silicate and calcium hydroxide are mixed, put in a tank 1, sealed with a sealing lid, heated with a heating coil, and heated to a hydrogen chloride gas concentration (pp.
m) was measured. The heating temperature is 200 ° C, 250 ° C, 3
00 ° C, 350 ° C, 400 ° C, 500 ° C, 600 ° C 7
The temperature was held at each temperature for 5 minutes, and the hydrogen chloride concentration (gas concentration) was measured. Measurement of gas concentration is based on JIS-
It was measured with a detector tube specified in K0804.

Table 1 shows the measurement results. The measured values shown in Table 1 are average values of the measured values in 10 experiments.

In the table, "*" indicates that no chlorine component was detected in any of the ten experiments.

[0034]

[Table 1]

From the above results, it was found that calcium silicate reacted with the chlorine component in the low temperature range and calcium hydroxide in the high temperature range, so that the chlorine was reliably immobilized.

From this, when waste containing chlorine components is subjected to dechlorination by dry distillation, one or both of calcium silicate and calcium hydroxide are mixed depending on the temperature of the heat treatment to produce waste. It can be seen that when added, the chlorine component can be effectively fixed, and the gas generated during the heat treatment does not contain the chlorine component.

Therefore, this gas became harmless even when burned, and could be effectively used as fuel.

The reason why the calcium hydroxide reacts with the chlorine component in the high temperature region and is fixed is that the waste gas-solid reacts with hydrogen chloride (HCL) generated at the time of thermal decomposition and alkali chloride @ Ca (CLO) ₂ 4H ₂ O · CaCL ₂ 4H ₂ O or the like is generated and the chlorine component is immobilized on the treated ash.

Therefore, it is clear that similar results can be obtained with alkaline substances other than calcium hydroxide.

The following can be used as the alkaline substance.

(A) Alkaline earth metal compounds: calcium hydroxide, calcium oxide, calcium carbonate magnesium hydroxide, magnesium oxide, magnesium carbonate barium hydroxide hydrate, barium oxide, barium carbonate strontium hydroxide, strontium carbonate dolomide ( (CaCO ₃ .MgCO ₃ ) (b) Alkali metal compound: sodium hydroxide, potassium hydroxide, lithium hydroxide hydrate sodium carbonate, potassium carbonate, potassium carbonate sodium sodium carbonate hydrate, lithium carbonate The reason for immobilization by reacting with chlorine components in the region is that calcium silicate hydrate is porous, has a large specific surface area and contains water, and contacts and adsorbs hydrogen chloride gas generated during thermal decomposition of waste. To fix the chlorine component in the treated ash The same operation and effect can be expected as long as the same operation is performed.

Therefore, it is clear that similar results can be obtained with silicates other than calcium silicate.

The following can be used as the silicate.

(A) Silicic acid hydrate: calcium silicate hydrate, magnesium silicate hydrate, dobamonide (5CaO
_{· 6Sio 2 · 5H 2 O)} (b) silicate compound: aluminum silicate, as a result of the sodium silicate above experimental investigation, the addition amount is preferably added 5-30 wt% of the waste to be treated, also It was found that when the temperature in the carbonization treatment step was in the range of 200 ° C. to 600 ° C., the chlorine component was reliably fixed.

Next, since the chlorine component is fixed in the treated ash taken out of the tank and cannot be discarded or burned as it is, it is necessary to perform a dechlorination treatment. Regarding this dechlorination treatment, the applicant of the present application has previously filed a patent application (Japanese Patent Application No. 7-319910).
As shown in FIG. 2, first, the treated ash (residue) is put into a water tank and stirred for a predetermined time (about 30 minutes) to dissolve the chlorine component in water. Next, this is dewatered and separated, and the chlorine component is removed from the treated ash, which is dried and solidified. Separated wastewater is dechlorinated separately by wastewater treatment means.

The residual chlorine component of the solidified treated ash was measured by ion chromatography and found to be 1,000 pp.
However, almost none at 5 ppm or less.

Further, depending on the physical properties of the residue, it is possible to separate the residue into various substances by a separation means, and to dry and solidify the separated substance to use the fuel or other effectively.

[0048]

As described above, the present invention relates to a chlorine component which is mixed with an additive which reacts with the chlorine component in a waste containing the chlorine component, subjected to dry distillation, and the chlorine component is fixed to the residue and gasified. And the heated gas containing no chlorine component was blown from the tuyere of the blast furnace as auxiliary fuel.
The following effects are obtained.

(1) Since the gas contains no chlorine component and contains a combustible component, it is suitable for use as an auxiliary fuel in a blast furnace, and dioxin is not discharged from the blast furnace.

(2) Pretreatment (separation, fine powder processing) of waste is not required, which can contribute to reduction of production cost.

(3) General municipal waste can also be heat-treated, thus exhibiting the effect of two birds per stone.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of the configuration of the present invention.

FIG. 2 is a conceptual diagram of a dechlorination treatment of treated ash.

FIG. 3 is a conceptual diagram of a configuration of a conventional blast furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Receiving hopper part 2 ... Pulverizing part 3 ... Sieving part 4 ... Supply hopper 5 ... Flow rate adjusting part 6 ... Conveyance piping 7 ... Pulverized coal hopper 8 ... Flow rate adjusting part 9 ... Air generation source 10 ... Powder distributor 11 ... Conveying piping 12 ... Blast furnace blowing branch pipe 13 ... Nozzle 14 ... Blast furnace 15 ... Tuyere 20 ... Tank 21 ... Sealing lid 22 ... Heating coil 23 ... Exhaust pipe with valve 24 ... Valve 25 ... Pump 26 ... Gas control means 27, 28: Valve 29: Gas storage tank 30: Gas supply pipe

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C21B 5/00 320 B09B 3/00 C10J 3/00 C10L 3/00, 5/48

Claims (10)

(57) [Claims] Claims: 1. A chlorine component-containing waste is mixed with an additive that reacts with the chlorine component and dry-distilled, and a chlorine component to be gasified is fixed to treated ash to obtain a heated gas containing no chlorine component. This gas is blown from the blast furnace tuyere as an auxiliary fuel , and the additive reacts with chlorine components.
Mixing at least two additives with different temperature ranges
A method for operating a blast furnace, characterized in that: 2. The method according to claim 1, wherein one of the additives is selected from a simple substance or a mixture of alkaline substances which react easily in a high-temperature region, and the other additive is selected from silicates which react easily in a low-temperature region. the method of operating a blast furnace of claim 1 Symbol placement. 3. The amount of the additive is 5 to 5% of the waste to be treated.
Blast furnace method of operation of Claim 1 Symbol mounting is characterized by adding 30 wt%. 4. The alkaline material is an alkaline earth metal,
The method for operating a blast furnace according to claim 2 , wherein the blast furnace is made of any one of an alkaline earth metal compound, an alkali metal, and an alkali metal compound, or a mixture thereof. 5. The operating method for a blast furnace according to claim 2 , wherein the alkaline substance as the additive is calcium hydroxide. 6. The method according to claim 2, wherein the additive silicate is a silicate hydrate. 7. The method for operating a blast furnace according to claim 2 , wherein the silicate hydrate is calcium silicate. 8. The mixing ratio of the two kinds of additives is as follows: (A) reacting in a low temperature region and (B) reacting in a high temperature region.
When the claim is characterized in that the A ≧ B 1 or
2. The method for operating a blast furnace according to 2 . 9. When the ratio of A: B is A: B = (1.5-4.
9. The method for operating a blast furnace according to claim 8, wherein 0) is set to 1. 10. The temperature of the carbonization treatment step is from 200 ° to 6 °.
00 ° C. and then the method of operation according to claim 1 Symbol placement blast furnace, characterized in that the.