WO2005080874A1

WO2005080874A1 - Waste fusion treatment method utilizing powdery biomass

Info

Publication number: WO2005080874A1
Application number: PCT/JP2004/017821
Authority: WO
Inventors: Hirokazu Tanaka; Yasuhiko Kato; Takeshi Nishi; Hideharu Shibaike; Yasusuke Hoshizawa; Yoshihiro Ishida
Original assignee: Nippon Steel Corporation
Priority date: 2004-02-24
Filing date: 2004-11-24
Publication date: 2005-09-01
Also published as: JP2005241054A; JP4486377B2

Abstract

A waste fusion treatment method utilizing biomass resource as a fusion heat source of a waste fusion furnace in place of coke and utilizing powdery biomass capable of suppressing production of CO2 resulting from fossil fuel. In the method for drying, thermally decomposing, combusting, and fusing waste by inputting waste into a waste fusion furnace of a shaft furnace type having a plurality of air supply tuyeres together with coke and limestone, supplying air from the upper tuyere (2) and supplying oxygen-rich air from the lower tuyere (3), combustion is performed by blowing powdery biomass from the lower tuyere (3).

Description

Waste melting method using powdered pyomas

Technical field

The present invention relates to a method for melting waste such as general waste and industrial waste, and more particularly to a method for melting waste using powdery pyomas.

Background art

General waste, industrial waste, or processed materials obtained by drying, incineration, crushing, etc., and landfilling these once, then reclaiming landfill waste including sediment reclaimed As a method, waste is melted and recycled as slag and metal.

Shaft furnace waste melting furnaces are used to directly melt waste (see JP-A-2001-90923). As shown in Fig. 2, the furnace body 1 is composed of a shaft la and a lower bosh section 5, and a lower tuyere 3 for the combustion melting zone is provided at the lower end of the bosh section 5. Above is a plurality of upper tuyeres 2 for the pyrolysis zone. Oxygen or oxygen-enriched air is supplied from the lower tuyere 3, and air is supplied from the upper tuyere 2 as a combustion supporting gas.

At the upper part of the furnace body, there is provided a charging inlet 11 for charging waste to be treated, coke as a combustion aid, limestone as a basicity adjusting agent, etc. into the furnace. The section is provided with a slag and metal tap 13 after the waste is melted.

In the above configuration, the charged waste 1 b is placed on the melting furnace body 1 From the layer, it passes through the drying zone 6, the thermal decomposition zone 7, and the combustion melting zone 8, and is melted.

The coke 4 and the pyrolysis residue 14 are burned at a high temperature by the oxygen or oxygen-enriched air supplied from the lower tuyere 3 and used as a heat source for melting, while air is supplied from the upper tuyere 2 and mainly disposed. Combustion of thermal decomposition residue 14 of wastes, and drying and thermal decomposition of waste with generated gas. The molten waste is discharged from the slag port 13 as slag and metal.

The high-temperature flue gas raises and melts the packed bed of waste in the shaft furnace as countercurrent, and is recovered as combustible gas from the flue gas pipe 12 at the top of the furnace body, or to the combustion chamber. Supplied. Combustion air is supplied to the combustion chamber via an air supply pipe, and is burned in the chamber. The flue gas is introduced into the boiler through an exhaust gas pipe, and after the waste heat is recovered, the temperature is adjusted in a cooling tower and passed through a dust collector, and after removing pollutants in a catalytic reaction tower, Emitted from the chimney.

On the other hand, because of the C0 ₂ reduction from the viewpoint of preventing global warming, C0 ₂ circulating in the short term service Ital, development related to utilization of biomass resources that can be immobilized has been promoted.

Also in direct melting furnaces, since use of coke made from fossil fuels as melting heat source, techniques for reducing the Kotasu usage to reduce the C0 ₂ loading on the environment is proposed. For example, combustible dust (char) discharged from the furnace top is collected as a means to reduce the coke as a fuel source as much as possible and to efficiently burn and melt the object to be treated. ^ A method of charging the melting furnace body through a tuyere (see JP-A-8-285250 and JP-A-2001-21123). Also, waste plastic is crushed. There is a method of loading from the top (see Japanese Patent Application Laid-Open No. 11-153309). Disclosure of the invention

Of the biomass resources, food waste, livestock manure, sewage sludge, and human waste sludge require proper disposal, but composting by fermentation has been mainly performed due to odor problems and transportation efficiency problems. . However, in the case of composting, from the viewpoint of transportation limitations, it is necessary that the source and the source are located close to each other, and that there is a balance between supply and demand. I have.

On the other hand, new technologies such as fermentation gasification and pyrolysis gasification power generation are being developed to utilize these biomass resources, but not only new capital investment is required, but also in the process It is necessary to secure the processing destination of the residue after fermentation and the carbide after thermal decomposition. Attempts have been made to use carbide as a fuel in private or commercial power plants as a treatment destination.However, when biomass resources are used for power generation, the amount of phosphorus and phosphorus concentration in combustion ash It is necessary to use only a very small amount because of the high cost and the problem of trouble due to the adhesion of the boiler tube.

In the waste melting furnace, coke consumption has been reduced by collecting combustible dust scattered from the melting furnace and blowing it together with oxygen from the lower tuyere. However, there was a problem that the amount of waste needed to replace the coke could not always be obtained because it increased or decreased depending on the composition of the waste.

Accordingly, the present invention is both when used as a melting heat source for the biomass resource waste melting furnace U one replacement task cost, waste utilizing powdery Paiomasu capable of suppressing the C0 ₂ generation of fossil fuel melting It provides a processing method.

According to the present invention, waste is charged together with coke and limestone into a shaft furnace type waste melting furnace having a plurality of blowing tuyeres, air is blown from an upper blowing tuyere and oxygen-rich from a lower blowing tuyere. Blowing the bubbling air In the waste melting treatment method for drying, pyrolyzing, burning, melting and melting the waste, the method is characterized in that the powdered biomass is blown into the furnace from the lower blast tuyere and burned. The summary is as follows.

(1) Waste is charged together with coatas and limestone into a shaft furnace waste melting furnace with multiple stages of tuyere and air is blown from the upper tuyere and from the lower tuyeres. In the waste melting method, which blows oxygen-enriched air to dry, pyrolyze, burn, and melt the waste,

A method for melting waste using powdery biomass, wherein powdery biomass is blown into a furnace from a lower-stage tuyere and burned.

(2) The powdery biomass is characterized by being livestock manure such as chicken dung and cow dung, food waste, sewage sludge, night soil sludge or residue after methane fermentation, dried matter such as construction waste material, or carbonized carbonized. A waste melting method using the powdered biomass as described.

(3) The powdered biomass described in (1) or (2) is characterized in that the volatile content of the powdered biomass is 5% by mass or more, the water content is 25% by mass or less, and the particle size is 10mm or less. Waste melting method.

(4) providing a blowing viewed mouth of the combustion supporting gas in the gas fuel and 0 ₂ such as LPG inside tuyere, and wherein the combusting by blowing powdery Paiomasu into the furnace (1) to (3) 13. The waste melting treatment method according to any one of the above items.

(5) The reaction molar ratio (oxygen ratio) between the amount of combustibles blown from the lower blast tuyere and the amount of coats charged into the furnace is 0.5 to the amount of oxygen supplied from the lower blast tuyere. : The amount of oxygen supplied from the lower blast tuyere or the amount of combustible material blown from the lower blast tuyere is adjusted so as to be in the range of 1.0. (1) to (4) Any Item 6. The waste melting treatment method according to item 1. Brief Description of Drawings

FIG. 1 is a diagram showing a process of waste melting treatment according to the present invention. FIG. 2 is a diagram showing a conventional waste melting process. BEST MODE FOR CARRYING OUT THE INVENTION

Biomass is classified by FA0 (International Food and Agriculture Organization), and in the present invention, woody biomass such as forest residue, thinned wood, unused 榭, sawmill residue, construction waste, rice straw, rice husk, etc., or papermaking Utilize unused biomass resources such as biomass, agricultural residues, livestock manure, food waste, etc., or charcoal after their carbonization.

In the present invention, biomass is dried to form a powder, or carbonized powder after carbonization is used.

For example, in the case of woody biomass, charcoal is produced by carbonizing woody biomass and subjecting it to sieve screening, or carbonizing the woody biomass for screening and pulverizing. Usually, it is easier to grind the carbonized material because the strength is weaker, and it requires less power. It is manufactured by carbonization in a patch furnace, rotary kiln or fluidized bed, or a shaft furnace as a carbonization furnace. In addition, a dust collector such as a cycle mouth is installed at the latter stage of the carbonization furnace, and the dust collected there can be used as it is as powdered carbide. Furthermore, in order to decompose the tar component contained in the exhaust gas from the carbonization furnace, it is conceivable to partially oxidize at 800 to 1200 ° C, but undecomposed dust and soot are also converted to powdery carbides. Available.

FIG. 1 is a diagram showing the steps of the waste melting treatment according to the present invention. The same components as those of the waste melting furnace shown in Fig. Is omitted. In FIG. 1, powdery biomass is blown from the lower tuyere 3.

Powder blown into the lower tuyeres, at a water content 25 wt% or less of the dry matter and child, moisture drying heat in a furnace feathers mouth, the water gas reaction endotherm _{(C + H 2 0 → C0} + H 2 ), And contributes as a heat source alternative heat source. If the volatile content is 5% by mass or more, the powder is blown at room temperature in the furnace, and if there is no volatile content, the ignition time is long and it does not contribute to the furnace bottom as a substitute for coke. It is.

The particle size of lOmin or less is the size required for airflow transport to the tuyere. In addition, by forming a flame at the tuyere and combusting it, it reacts with oxygen before the coat and is the size necessary to replace the coat.

Pulverized biomass, such as charcoal of woody biomass, has almost no inorganic components and high calorific value.However, such as dry sludge and powdered biomass containing a little water, And low flammability. In order to use such carbides as substitutes for coats in the waste melting furnace, it is necessary to improve the flammability at the tuyere. Therefore, by providing a gas fuel such as LPG and a combustion support gas such as O ₂ inside the tuyere, it is possible to use the flame of LPG ZO ₂ as the ignition source. Low-leakage biomass fuel can be used as a substitute for coke.

In addition, as a result of experiments, it was found that there is an optimum value for the amount of combustible material blown from the tuyere when the waste melting furnace is effectively used as a substitute for the coater. That is, the reaction molar ratio (oxygen ratio) of the amount of combustible material blown from the lower blast tuyere and the amount of coke charged into the furnace with respect to the amount of oxygen supplied from the lower blast tuyere is 0. The range is from 5 to 1.0. If the oxygen ratio is lower, the amount And it becomes difficult to maintain operation at a low coatas ratio of about 2%. When the oxygen ratio is higher than that, C and H in the combustibles blown cause an endothermic reaction to lower the slag temperature. In the case of excessive blowing, C that is not consumed in the furnace re-scatters, and the amount of dust collected by the dust remover increases rapidly, making it impossible to process in the melting furnace.

When the ratio was experimentally determined, it was found that when the oxygen ratio was 0.5 to: L. 0, it was possible to perform lotus rotation with a stable slag temperature while keeping the coke ratio low. Example 1

In this example, municipal solid waste with an ash content of 15% to 20% was melted and used as carbonaceous biomass as powdered biomass. The properties of the carbide at that time were as follows: carbon: 90%, calorie: 7000 Kcal / kg, average particle size: 40 μm. The amount of injected carbohydrate was 35 _kg h. The waste disposal rate was 850 kgZh.

The blowing conditions were as follows: lower air volume ΖδΟΝιη ³ / h, oxygen volume 60 Nm ³ Z h, and upper air volume 350 Nm ³ / h. At this time, the amount of coke added as auxiliary material was 2% to the refuse and limestone was added to 5%. The slag and metal carried out of the melting furnace are carried out at an average temperature of about 1500 ° C. There is no deterioration in the fluidity, and the lead content in the slag is 0 or less. Was not detected. This was achieved by injecting biomass with a coke addition amount of about 2%, compared to the case where no nomas were injected from the tuyere.

Example 2 In this example, sewage sludge carbide was used as powdery carbide. The properties of the carbide at that time were: C: 25%, Calorie: SOOOkcalZk ^ Average particle size: 1 mm. The amount of carbide injected was 100 kgZh. The waste disposal rate was 840 kg / h.

The blowing conditions were as follows: the lower air volume was 250Nm ³ // h, the oxygen volume was SONm ³ / h, and the upper oxygen volume was 350Nm ³ _ h. At this time, the amount of coke added could not be reduced by simply blowing, because the calories of the carbides were low and the particle size was large. Therefore, using a triple tube tuyere which may be added in the LPG and 0 ₂ in the internal tuyere, LPG and l Nm ³ / h, and the O ₂ and 5 Nm ³ Zh added. As a result, it has become possible to reduce the amount of the costas added by 2%.

Table 1 shows the operating conditions and results of Examples 1 and 2.

table 1

Example Base condition Example 1 Example 2 Treated material General waste

Ash content 15-20%, wet base

Processing speed ( _kg / h) 833 850 845 Biomass used None Building waste (pulverized carbide) Sewage sludge

C (%)-90 25 Calorific value (kcal / kg)-7000 2000 Average particle size (μm)-40 1000 Biomass injection-35 100 Coke consumption (kgZh) 40 17 17

LPG blowing amount (Nm ³ h) 0 0 1

0 ₂ Injection volume (Nm ³ Zh) 0 0 5 Slag temperature C) 1534 1547 1522 * Blowing conditions: lower blowing rate 250 Nm ³ / h, the lower the oxygen-flow quantity 60 Nm ³ Z h, the availability of the fixed industrial above stage blast volume 350 Nm ³ / h

The present invention provides a waste melting furnace, since the coke consumption Ri by the be combusted in a furnace by blowing powdery biomass from the lower air blowing tuyeres can be suppressed, by C0 ₂ generation of fossil fuel can be prevented Instead, it is possible to use biomass-derived fuel without reducing the amount of waste processed in the melting furnace. Et al is, Ri particular good performing vapor recovery power generation by boiler in a subsequent exhaust gas treatment system of a waste melting furnace, heat energy, upon conversion to electric energy, similarly C0 ₂ generation fossil fuels Origin Can be suppressed.

Claims

1. The waste is charged together with the coatus and limestone into a shaft-type waste melting furnace with multiple blast tuyeres, air is blown from the upper blast tuyeres, and oxygen-enriched air is blown from the lower blast tuyeres. To dry, pyrolyze, burn, and melt the waste.

hand,

A method for melting waste using powdery biomass, wherein the biomass is blown into a furnace through a lower tuyere and burned.

2. The powdery biomass is a livestock excrement such as chicken dung and cow dung, food waste, sewage sludge, human waste sludge or a residue after methane fermentation, or a dry matter such as construction waste material or a dry carbonized charcoal. Item 1. A waste melting treatment method using the powdered pyomasu according to Item 1.

3. Waste melting using powdered biomass according to claim 1 or 2, wherein volatile matter of the powdered biomass is 5% by mass or more, moisture is 25% by mass or less, and particle size is 10mm or less. Processing method.

4. An air inlet for gas fuel such as LPG and a combustion supporting gas such as O ₂ is provided inside the tuyere, and powdered pyomas is blown into the furnace for combustion. Or the waste melting method according to item 1.

5. The reaction molar ratio (oxygen ratio) between the amount of combustibles blown from the lower blast tuyere and the amount of coats charged into the furnace is set to 0.5 to 5 to the amount of oxygen supplied from the lower blast tuyere. The amount of oxygen supplied from the lower blast tuyere or the amount of combustible material blown from the lower blast tuyere is adjusted so as to fall within the range of L0. Or the waste melting method according to item 1.