JP2014193798A - Method and apparatus for converting garbage incineration ash into cement raw material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convert garbage incineration ash into resources as a cement raw material while suppressing equipment cost and operation cost to a low level.SOLUTION: An apparatus 1 for converting garbage incineration ash into a cement raw material comprises: a first reaction tank 3 for producing an incineration ash slurry S by mixing garbage incineration ash BA and water W; an acidic gas introduction device 4 for introducing an acidic gas G1 into the first reaction tank; a specific gravity difference classifier for performing specific gravity difference classification using a bubble flow of acidic gas in the first reaction tank; a classifier 6 for classifying an incineration ash slurry S2 having a small specific gravity classified by specific gravity difference classification into a slurry S3 comprising coarse particles and a slurry S4 comprising fine particles; a second reaction tank 8 for reserving the slurry comprising fine particles; an acidic gas introduction device for introducing an acidic gas G2 into the second reaction tank; and a solid-liquid separator 9 for performing solid-liquid separation of the slurry S5 resulting from the second reaction tank.

Description

  TECHNICAL FIELD The present invention relates to a method and apparatus for recycling waste incineration ash (main ash) generated when municipal waste or the like is incinerated as a cement raw material.

  Most of the incineration ash (hereinafter referred to as “waste incineration ash”) generated when incinerating municipal waste has been landfilled at the final disposal site, but in view of the danger of depletion of the final disposal site, In recent years, it has been effectively used as a cement raw material.

  Waste incineration ash contains about 1.2% of chlorine on average, and this chlorine prevents deterioration of cement quality and stable operation of cement manufacturing equipment. There is a need.

  Therefore, for example, in Patent Document 1, a crushing step in which water is added to incineration ash to crush particles in the incineration ash to agitate the incineration ash slurry, and the incineration ash slurry is passed through a screening sieve. An incineration ash having a foreign matter removal process for removing excessive solids, a dehydration process for dewatering the incinerated ash slurry that has passed through the screening sieve with a sieve for draining, and a rinse washing process for rinsing and washing the incinerated ash that has passed through the dehydration process. A cleaning method and the like are described.

  In addition to soluble salts, there are also sparingly soluble Friedel's salts in the main ash, so after pulverizing the entire amount of the main ash, Friedel's salt is decomposed with acid and effectively used as a raw material for cement. (See Patent Document 2).

JP 2012-166170 A JP 2006-326462 A

  However, in the cement raw material conversion method as described in Patent Document 1, a large amount of water is consumed in the crushing process and the rinsing and cleaning process, so that the operation cost and the equipment cost increase.

  In addition, as described in Patent Document 2, in order to pulverize the total amount of main ash received and treat with acid, the scale of the pulverization equipment and the like increase in size and energy cost, and the operating cost and equipment cost are reduced. There was a problem of soaring.

  Therefore, an object of the present invention is to turn waste incineration ash into a cement raw material while keeping facility costs and operation costs low.

  In order to achieve the above object, the present invention is a method for converting waste incineration ash into a cement raw material, wherein an acid gas is introduced into an incineration ash slurry in which waste incineration ash and water are mixed, and a bubble flow of the acid gas is used. The incinerated ash slurry having a small specific gravity classified by the specific gravity differential class is classified into a slurry containing coarse particles and a slurry containing fine particles, and the slurry containing the classified fine particles is solid-liquid. The cake obtained by the separation is used as a cement raw material.

  According to the cement raw material production method according to the present invention, without pulverizing the entire amount of the refuse incineration ash, in parallel with the specific gravity difference class and the classification treatment, acid gas is introduced to form the hardly soluble salt. Because it decomposes, waste incineration ash can be used as a cement raw material while keeping facility costs and operation costs low.

  In the above cement raw material production method, the solid-liquid ratio of the incinerated ash slurry can be adjusted to 1: 1 or more and 1 to 5 or less, whereby a hardly soluble salt in the slurry containing fine particles having a high chlorine content. Can be effectively decomposed.

  Moreover, the hardly soluble salt contained in refuse incineration ash can be decomposed | disassembled more effectively by introduce | transducing acidic gas or an acid into the slurry containing microparticles | fine-particles.

  In the cement raw material conversion method, as the acid gas, exhaust gas from a cement kiln or / and exhaust gas from a chlorine bypass facility can be used, and exhaust gas from the cement firing step can be effectively used.

  Furthermore, the maximum particle size of the fine particles can be adjusted to 1 mm or less, whereby the hardly soluble salt in the slurry containing fine particles having a high chlorine content can be effectively decomposed.

  Further, the present invention is a cement raw material conversion apparatus, a reaction tank for mixing waste incineration ash and water to produce an incineration ash slurry, an acid gas introduction apparatus for introducing an acid gas into the reaction tank, In the reaction tank, a specific gravity differential classifier that performs a specific gravity differential class using the bubbly flow of the acid gas, an incineration ash slurry having a small specific gravity classified by the specific gravity differential class, a slurry containing coarse particles, and a fine particle A classification device for classifying the slurry containing the slurry, and a solid-liquid separation device for solid-liquid separation of the slurry containing the classified fine particles.

  According to the present invention, as in the case of the above-described invention, in parallel with performing the specific gravity difference class and the classification process, by introducing the acidic gas and decomposing the hardly soluble salt, the facility cost and the operation cost are kept low. Waste incineration ash can be used as a raw material for cement.

  Furthermore, this invention is a cement raw material conversion apparatus, Comprising: The 1st reaction tank which mixes refuse incineration ash and water and produces | generates an incineration ash slurry, and introduce | transduces acidic gas into this 1st reaction tank In the gas introduction device, in the first reaction tank, a specific gravity differential classifying device that performs a specific gravity differential class using a bubbly flow of the acidic gas, and an incineration ash slurry having a small specific gravity classified by the specific gravity differential class, A classifying device for classifying into a slurry containing particles, a slurry containing fine particles, a second reaction tank for storing the slurry containing fine particles, and a second acid gas introducing device for introducing acid gas into the second reaction tank; And a solid-liquid separator for solid-liquid separation of the slurry from the second reaction tank.

  ADVANTAGE OF THE INVENTION According to this invention, the hardly soluble salt contained in refuse incineration ash can be decomposed | disassembled more effectively by introduce | transducing acidic gas into the 2nd reaction tank which stores the slurry containing microparticles | fine-particles.

  As described above, according to the present invention, waste incineration ash can be used as a cement raw material while keeping facility costs and operation costs low.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows one Embodiment of the cement raw material production apparatus concerning this invention.

  Next, an embodiment of a cement raw material producing apparatus according to the present invention will be described with reference to FIG. In FIG. 1, a broken arrow indicates a liquid flow, an alternate long and short dash arrow indicates a gas flow, and a solid arrow indicates a solid (including slurry) flow.

  FIG. 1 shows an embodiment of a cement raw material production apparatus according to the present invention. This cement raw material production apparatus 1 is a main ash tank 2 for storing received refuse incineration ash (hereinafter referred to as “main ash”) BA. And the main ash BA and water W etc. are mixed to produce the main ash slurry S, and the specific gravity from the first reaction tank 3 and the first reaction tank 3 in which the acid gas G1 is introduced to perform the specific gravity differential class. Draining device 5 for dehydrating main ash slurry S1 having a large particle size, and classifying device 6 for classifying main ash slurry S2 having a small specific gravity from first reaction tank 3 into slurry S3 containing coarse particles and slurry S4 containing fine particles. A second reaction tank 8 for reacting the slurry S4 containing fine particles from the classifier 6 with the acid gas G2, and an acid gas introduction apparatus for introducing the acid gases G1 and G2 into the first reaction tank 3 and the second reaction tank 8. 4 and slurry S from the second reaction tank 8 The solid-liquid separation comprised of solid-liquid separator 9 and the like.

  The first reaction tank 3 is provided to mix the main ash BA, water W, and the filtrate F1 and the waste water W2 from the solid-liquid separator 9 to generate the main ash slurry S and react with the acid gas G1. The solid-liquid ratio is preferably 1: 1 to 1: 5. The first reaction tank 3 also has a function as a specific gravity differential classifier that performs a specific gravity differential class using the bubbly flow of the acid gas G1, and has a large specific gravity main ash slurry S1 containing particles having a particle diameter exceeding 2 mm. And main ash slurry S2 having a small specific gravity and containing particles having a particle size of 2 mm or less.

The acid gas introduction device 4 is provided to introduce the acid gases G1 and G2 into the first reaction tank 3 and the second reaction tank 8, and as the introduced acid gas, exhaust gas from a cement kiln containing a large amount of CO ₂ or SO The exhaust gas from the chlorine bypass facility containing a large amount of ₂ can be used.

  The classifier 6 is provided for classifying the main ash slurry S2 having a small specific gravity from the first reaction tank 3 into a slurry S3 containing coarse particles and a slurry S4 containing fine particles, and 0.7 mm is defined as a classification point. A sieve is built in, and classification and draining are performed using the air from the air blowing device 7.

  Next, the operation of the cement raw material producing apparatus according to the present invention will be described with reference to the drawings.

  First, in the first reaction tank 3, the main ash BA is mixed with water W to make a slurry, and the acid gas G1 is introduced into the main ash slurry S from the acid gas introducing device 4, and the Friedel contained in the main ash BA. Decompose Mr. salt. At the same time, the specific gravity differential class of the main ash slurry S is performed using the bubbly flow of the acid gas G1.

In addition, Friedel's salt is 3CaO · Al ₂ O ₃ · CaCl ₂ · 10H ₂ O in chemical formula, and trilime aluminate (3CaO · Al ₂ O ₃ ) is hydrated as described below. It is a salt produced by taking in chloride ions during the reaction.
3CaO.Al ₂ O ₃ + CaCl ₂ + 10H ₂ O → 3CaO.Al ₂ O ₃ .CaCl ₂ .10H ₂ O

When exhaust gas of cement kiln is blown into the slurry as acidic gas G1, Friedel's salt can be decomposed as shown in the following formula.
_{3CaO · Al 2 O 3 · CaCl} 2 · 10H 2 O + 3CO 2 → 3CaCO 3 + 2Al (OH) 3 + CaCl 2 + 7H 2 O

Further, when the exhaust gas of the chlorine bypass facility is blown into the slurry as the acidic gas G1, Friedel's salt can be decomposed as shown in the following formula.
_{3CaO · Al 2 O 3 · CaCl} 2 · 10H 2 O + XSO 4 2- → 3CaO · Al 2 O 3 · 3CaSO 4 · 32H 2 O + YCl -

  By this specific gravity difference class, the main ash slurry S is separated into a main ash slurry S1 having a large specific gravity containing particles having a particle size of more than 2 mm and a main ash slurry S2 having a small specific gravity containing particles having a particle size of 2 mm or less. Slurry S1 is dehydrated by draining device 5, and cake C1 after dehydration is used as cement raw material R in a calcining furnace of cement firing device 10. Further, the water W4 separated by dehydration is supplied to the second reaction tank 8.

  On the other hand, the main ash slurry S2 having a small specific gravity and containing particles having a particle size of 2 mm or less is introduced into the classifying device 6 and is classified and drained using the air from the air blow device 7 to obtain a particle size of 0.7 mm. Slurry S3 containing excess coarse particles remains on the sieve, and slurry S4 containing fine particles having a particle size of 0.7 mm or less is guided to the second reaction tank 8. Since the slurry S3 containing the classified coarse particles has a certain amount of moisture removed, it is directly fed into the calcining furnace of the cement firing device 10 as the cement raw material R together with the cake C1 from the draining device 5.

  Next, in the 2nd reaction tank 8, acidic gas G2 is introduce | transduced from the acidic gas introduction apparatus 4 with respect to slurry S4 containing microparticles | fine-particles, and Friedel's salt contained in slurry S4 is further decomposed | disassembled. The reason why the slurry S4 containing the fine particles is subjected to the reaction with the acid gas G2 is that the particles having a small particle size contain a large amount of chlorine. At this time, the pH in the second reaction tank 8 is adjusted to 4 to 10.5.

  The slurry S5 that has finished the reaction with the acid gas G2 is introduced into the solid-liquid separator 9, and after being washed with the cake washing water (new water) W1, or dehydrated while being washed. The dehydrated cake C2 is fed as a cement raw material R into the calcining furnace of the cement firing apparatus 10. Moreover, the waste water W3 of the solid-liquid separator 9 is discharged after the waste water treatment, and a part of the waste water W2 is returned to the first reaction tank 3 for circulation. Further, the filtrate F1 separated by the solid-liquid separator 9 can also be returned to the first reaction tank 3 and reused. At this time, it is preferable to determine the circulation amount of the waste water W2 while measuring the electrical conductivity of the filtrate F1 and managing the chlorine concentration of the filtrate F1.

  In the above embodiment, the main ash slurry S is generated from the main ash BA and water W in the first reaction tank 3, and the specific gravity difference class is obtained using the bubbly flow of the acid gas G 1 in the first reaction tank 3. However, the slurrying of the main ash BA and the specific gravity difference class device using the bubbly flow of the acid gas G1 can also be performed in separate devices.

  Further, the acidic gas G2 from the acidic gas introduction device 4 was also introduced into the second reaction tank 8 to decompose the hardly soluble salt, but the chlorine content of the main ash BA received and the Friedel in the first reaction tank 3 Depending on the decomposition state of the salt, it is not always necessary to introduce the acidic gas G2 into the second reaction tank 8 to decompose the hardly soluble salt, and the slurry S4 from the classification device 6 is introduced into the solid-liquid separation device 9 as it is. Solid-liquid separation can also be performed.

  Moreover, although the classification point in the specific gravity difference class of the first reaction tank 3 is 2 mm and the classification point of the classification device 6 is 0.7 mm, these classification points are appropriately set according to the operation status of the cement raw material converting apparatus 1 and the like. Can be changed. However, the classification point of the classification device 6 is preferably 1 mm or less in order to effectively remove chlorine.

  In addition to adding the slurry S3 containing coarse particles to the calcining furnace of the cement baking apparatus 10, it can also be used as a raw material for preparation.

  Furthermore, an acid such as sulfuric acid, nitric acid, acetic acid, and formic acid may be added without introducing the acidic gas G2 into the second reaction tank 8.

Moreover, not only the acidic gas G and the acid but also an oxidizing gas such as O ₃ can be introduced into the second reaction tank 8 to reduce the COD, thereby reducing the load of the subsequent waste water treatment. Without introducing the oxidizing gas into the second reaction tank 8, the tank can be multi-staged, and the acidic gas G and the oxidizing gas can be introduced separately.

  Furthermore, although acidic gas G1 and G2 were introduce | transduced into the 1st reaction tank 3 and the 2nd reaction tank 8 from one unit | set of the acidic gas introduction apparatus 4, it separates into each of the 1st reaction tank 3 and the 2nd reaction tank 8. Of course, it is also possible to introduce the acid gas from the acid gas introduction apparatus.

DESCRIPTION OF SYMBOLS 1 Cement raw material production apparatus 2 Main ash tank 3 1st reaction tank 4 Acid gas introduction apparatus 5 Drainage apparatus 6 Classification apparatus 7 Air blow apparatus 8 2nd reaction tank 9 Solid-liquid separation apparatus 10 Cement baking apparatus

Claims (7)

Introducing acid gas into the incineration ash slurry, which is a mixture of waste incineration ash and water, and using the bubbly flow of the acid gas to perform a specific gravity differential class,
The incinerated ash slurry having a small specific gravity classified by the specific gravity differential class is classified into a slurry containing coarse particles and a slurry containing fine particles,
Solid-liquid separation of the slurry containing the classified fine particles,
A method for converting waste incinerated ash into a cement material, wherein the cake obtained by the solid-liquid separation is used as a cement material.   The solid-liquid ratio of the incineration ash slurry is adjusted to 1: 1 or more and 1 to 5 or less, The method for converting waste incineration ash into a cement raw material according to claim 1.   3. The method of converting waste incinerated ash into a cement raw material according to claim 1, wherein an acid gas or an acid is introduced into the slurry containing the fine particles.   The method for converting waste incinerated ash into a cement raw material according to claim 1, 2 or 3, wherein the acid gas is exhaust gas from a cement kiln or / and exhaust gas from a chlorine bypass facility.   The method for converting waste incinerated ash into a cement raw material according to any one of claims 1 to 4, wherein the maximum particle size of the fine particles is adjusted to 1 mm or less. A reaction tank for mixing incineration ash and water to produce an incineration ash slurry;
An acidic gas introduction device for introducing acidic gas into the reaction vessel;
In the reaction vessel, a specific gravity differential classifier that performs a specific gravity differential class using a bubbly flow of the acid gas;
A classification device for classifying the incinerated ash slurry having a small specific gravity classified by the specific gravity differential class into a slurry containing coarse particles and a slurry containing fine particles;
An apparatus for converting waste incinerated ash into a cement raw material, comprising: a solid-liquid separation device for solid-liquid separation of the slurry containing the classified fine particles. A first reaction tank for mixing incineration ash and water to produce an incineration ash slurry;
A first acidic gas introduction device for introducing acidic gas into the first reaction tank;
In the first reaction tank, a specific gravity differential classifier that performs a specific gravity differential class using the bubbly flow of the acid gas;
A classification device for classifying the incinerated ash slurry having a small specific gravity classified by the specific gravity differential class into a slurry containing coarse particles and a slurry containing fine particles;
A second reaction tank for storing a slurry containing the fine particles;
A second acid gas introduction device for introducing acid gas into the second reaction tank;
An apparatus for converting waste incinerated ash into a cement material, comprising: a solid-liquid separation device for solid-liquid separation of the slurry from the second reaction tank.

Images