JPH11169815A - Method for briquetting waste incineration ash - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the briquette having a necessary strength in handling without being aged and having a sufficient strength against the mechanical and thermal impact when charged into a melting furnace by admixing oil with an incineration ash in a specified ratio and briquetting the admixture by a briquetting machine. SOLUTION: The incineration ash of waste is briquetted and then melted in a vertical melting furnace. In this case, 100 pts.wt. of incineration ash is admixed with 1-20 pts.wt. of oil, and the admixture is briquetted by a briquetting machine. The oil is selected from mineral oil, vegetable oil, grease, heavy oil, waste lubricant and waste edible oil. Such oil acts as a binder for the incineration ash, hence the viscosity should be high, and the kinematic viscosity at 40 deg.C is preferably controlled as 100 cSt. Besides, the oil may contain such harmful matter as heavy metals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is carried out before melting and solidifying incinerated ash generated mainly by incinerating waste such as municipal solid waste and sewage sludge for volume reduction and detoxification. And a method for briquetting incinerated ash.

[0002]

[Prior Art] When municipal waste and sewage sludge are incinerated,
Furnace ash and fly ash are generated. The combined incineration ash is often landfilled at a final disposal site. However, incinerated ash often contains harmful substances such as heavy metals, which may cause secondary pollution.
In recent years, the number of places that can be landfilled has decreased,
It is difficult to secure for the future.

[0003] Therefore, attempts have been made to melt incinerated ash to reduce its volume. For the melting treatment of such incinerated ash,
Various methods have been proposed. Apparatuses developed to date have generally high initial and running costs and are suitable for large-scale implementations, and have been difficult to adopt unless installed in waste incineration plants in large cities.

[0004] Under such circumstances, a vertical melting furnace is considered to be promising as an incineration ash melting apparatus suitable for relatively small-scale implementation. The main components of the incineration ash are SiO ₂ , Al ₂ O ₃ and CaO.
If it is kept at a high temperature of about 500 ° C., it melts, and the solidified melt can be used as an artificial aggregate.

[0005] In order to melt incineration ash in a vertical melting furnace, it is necessary to make the incineration ash into a mass such as briquettes, tablets or pellets before charging the furnace. It is needless to say that the ventilation in the furnace is made uniform and the generation of fly ash in the melting furnace is minimized.
In addition, since this lump must not collapse and become powdered by mechanical and thermal shock when charged into a furnace, it is required to have a certain degree of thermal shock resistance. You.

The first method of forming a lump was to add slaked lime to incinerated ash, knead it with a little water, knead it, and cure it for several hours to several days to increase the strength by hydration. Expression. However, curing requires equipment and complicates the treatment process.
As a problem before that, there is a problem that the molded body until the strength is obtained by curing is easily broken. Therefore,
There has been a demand for a molding technique capable of immediately obtaining the required strength without curing after molding.

[0007] As a molding technique responding to this, it has been attempted to use a glue as a binder and knead it with incineration ash together with water. By this method, the strength of the incinerated ash compact reached a certain level, and it became possible to omit curing as far as handling of the compact was concerned. However, the incinerated ash compact using the glue as a binder tends to be ruptured and powdered by thermal shock when put into a melting furnace. Along with that, the obstruction of the ventilation of the furnace mentioned above,
The problem of increasing the amount of fly ash generated in the melting furnace is inevitable. If a sufficient amount of the gluing agent is used, the cost will be greatly affected, and further cost reduction is required.

[0008]

SUMMARY OF THE INVENTION The main object of the present invention is to provide a briquette prior to melting incineration ash.
To provide a briquetting method capable of obtaining briquettes having sufficient strength in handling without curing and having sufficient strength against mechanical shock and thermal shock when put into a melting furnace. is there.

A secondary object of the present invention is to provide a method for harmlessly treating various waste oils, which are also wastes to be treated, in the melting treatment of incinerated ash.

[0010]

The basic aspect of the method for briquetting waste incinerated ash of the present invention is a method for briquetting waste incinerated ash prior to melting it in a vertical melting furnace. 1 to 20 parts by weight of oil are added to 100 parts by weight of incinerated ash, and the mixture is briquetted by a briquetting machine.

A preferred embodiment of the method for briquetting waste incinerated ash of the present invention is a method for briquetting waste incinerated ash prior to melting it in a vertical melting furnace, wherein the incinerated ash is dried and dried. Oil 1-2 for 100 parts by weight of incinerated ash
0 parts by weight and 1 to 15 parts by weight of water are added and mixed, and the mixture is briquetted by a briquetting machine.

[0012]

DETAILED DESCRIPTION OF THE INVENTION Oils include mineral oils, vegetable oils, animal oils,
What was selected from grease, heavy oil, waste lubricating oil, and waste cooking oil may be used. Since this oil plays a role of a binder for the incineration ash, it is preferable that the oil has a high viscosity, and it is preferable to use an oil having a kinematic viscosity at 40 ° C of 100 cSt or more. Since the oil is burned by being exposed to the high temperature of the melting furnace together with the incineration ash, it may contain harmful substances such as heavy metals. Even if heavy metals are contained, they migrate into the molten slag and are rendered harmless together with harmful substances in the incineration ash.

In order to function as a binder, it is necessary to add at least 1 part by weight of oil to 100 parts by weight of incinerated ash. If the amount becomes large, the briquette is immediately burned when the briquette is put into the melting furnace, and the temperature of the exhaust gas is unnecessarily increased. Therefore, it is desirable to limit the amount to 20 parts by weight and to minimize the amount as much as possible. Usually, 3 to 10 parts by weight is appropriate.

After the incinerated ash is taken out of the incinerator, it is generally subjected to treatment such as spraying with water, and its water content usually reaches about 10% by weight. When briquetting using oils according to the present invention, it has been found that the addition of an appropriate amount of moisture gives better performance. In order to reliably obtain the effect of adding water, it is necessary to control the amount of water to be added as accurately as possible. For this purpose, the incinerated ash is once dried to substantially eliminate the water, and then the prescribed amount is determined. It is the preferred embodiment described above that the way of adding water is selected.

For drying the incinerated ash, the heat of the exhaust gas from the melting furnace can be used. Normally, this exhaust gas is used to exchange heat with the air supplied to the furnace and preheat it, but since it has a sufficient amount of heat thereafter, it is dried by direct contact with incineration ash, for example. Can be done. By drying, the incinerated ash easily has a water content of 1% by weight or less.

The addition or mixing of oil or oil and water to the incineration ash can be performed using any kneading apparatus.
Briquetting of the mixture can also be performed utilizing any briquetting machine. If a briquetting machine having a high pressing force is used, briquettes having higher strength can be obtained, but a conventional one, that is, a roll type having a linear pressure of about 3 to 4 t / cm is sufficient.

Ingredients to be added to the incinerated ash are also useful in addition to oil and water, as well as alkaline substances. Specifically, sodium carbonate, sodium hydrogen carbonate, and caustic soda are added in an amount of 2 parts by weight or less per 100 parts by weight of incinerated ash. Of course, the potassium salt may be used, but the sodium salt is lower in cost, and soda ash (mainly sodium carbonate) is the cheapest. The alkaline substance may be added as a solid powder or in the form of an aqueous solution, and a part or all of the water to be added may be supplied from this aqueous solution.

It is understood that the action of the alkali substance causes a saponification reaction when the oil is glyceride, but it is not limited to the saponification because the effect of addition can be seen even when the oil is glyceride. That is, details are unknown. Even if the alkali substance is added in an excessively large amount, an effect corresponding thereto cannot be obtained. Therefore, an appropriate addition amount is selected within the above 5 parts by weight.

As described above, slaked lime has been added to incinerated ash when molding is performed on the premise of curing briquettes in the prior art. This utilizes a reaction between incinerated ash and components of the incinerated ash, and is a mechanism that cannot be expected in the present invention that omits curing, but slaked lime itself is briquette. In view of utilizing this aptitude, it is an advantageous embodiment to add slaked lime to incinerated ash in the sense of utilizing this aptitude.

When slaked lime is added, its amount is optional, but the amount of the effect that becomes clear is 5 parts by weight or more based on 100 parts by weight of incinerated ash. Although the addition of a large amount increases the amount of molten slag, as described above, the main components of the incinerated ash are SiO ₂ and Al ₂ O ₃ , and in order to make the basicity of the melt within an appropriate range, In any case, separately C
Since it is necessary to add the aO component, if slaked lime is added as the CaO source, the amount of slag does not increase separately. Therefore, the appropriate amount of slaked lime depends on the composition of the incinerated ash, that is, the ratio of the acid component / base component, but the upper limit is 60 parts by weight of slaked lime with respect to 100 parts by weight of the incinerated ash. Usually 10-20
Parts by weight are appropriate.

[0021]

Next, the present invention will be described in more detail by way of examples.

As the objects to be treated, three types of incinerated ash of A, B and C were taken up. The chemical analysis values are shown in Table 1, and the particle size distribution is shown in Table 2.

Table 1 (% by weight) Ash ig-los SiO ₂ Fe ₂ O ₃ Al ₂ O ₃ CaO MgO PS CO ₂ CK ₂ O Na ₂ O A 7.62 29.40 6.70 31.80 10.19 3.88 1.868 0.376 1.51 3.27 1.71 2.25 B 5.60 27.63 1.38 44.14 14.44 3.89 0.120 0.241 0.40 2.56 0.71 0.59 C 8.26 40.46 2.91 27.03 4.22 1.95 3.500 0.210 0.70 1.18 1.63 0.58 Table 2 (mm) Gray +2.0 1.70 1.00 0.60 0.35 0.15 0.075 0.045 -0.045 A 5.5 1.7 4.5 5.8 8.3 17.7 18.1 11.3 27.1 B 0 0.3 4.3 5.3 7.9 19.3 21.3 12.2 29.4 C 0 0.2 2.9 3.6 3.8 12.3 21.1 15.6 40.5 The oil absorption and the water absorption of the incinerated ash were measured according to the oil absorption measurement method of "Pigment measurement method" defined in JIS K5101. The results are as shown in Table 3 below.

Table 3 (Weight%) Incinerated ash Oil absorption Water absorption A 56.0 63.6 B 91.6 94.0 C 91.4 101.0 Test Examples 1 to 9 The ash composition was prepared, filled in a circular die having an inner diameter of 40 mm, and pressed uniaxially under various pressures, and the density of the obtained 12.5 mm thick disc-shaped briquettes (tablets) was measured. The results are shown in Table 4.

Table 4 Mixing ratio (parts by weight) Tap forming pressure (t / cm ² ) No. Incinerated ash Slaked lime Water Soda ash Filled with C heavy oil 0.5 1.0 2.0 3.0 1 A100----1.18 1.48 1.48 1.62 1.62 2 A100 10 10 − − 0.97 1.70 1.83 1.90 1.98 3 A100 10 6 19 9 0.82 1.78 1.84 1.96 2.03 4 B100 − − − − 0.64 1.34 1.49 1.50 1.53 5 B100 10 10 − − 0.63 1.65 1.69 1.81 1.81 6 B100 10 6 1 9 0.65 1.58 1.75 1.83 1.93 7 C100----0.74 1.15 1.25 1.42 1.47 8 C100 10 10--0.76 1.30 1.45 1.62 1.68 9 C100 10 6 19 9 0.74 1.46 1.66 1.78 1.84 [Test Examples 10 to 49] Take incineration ash A, and weigh 100 weight. The parts shown in Table 5 were added and mixed to each part, and the mixture was filled in the same circular die as in Test Examples 1 to 9 and press-formed uniaxially at a pressure of 0.8 t / cm ² . Two kinds of the same composition were prepared, one was mixed at room temperature, and the other was mixed by warming all components to 70 ° C. In the latter case, the temperature often rises to about 70 ° C. in an operation in actual briquetting, and therefore, it is to know what result will be obtained in that case.

The obtained tablet was dropped on a concrete plate from a height of 2 m, and the state of the damage was examined (n = 10). The results are shown in Table 5.

Table 5 No. Slaked lime C heavy oil NaOH aqueous solution Room temperature drop test 70 ° C drop test 10 10 10.5 (5% solution 4.5) ○ ○ 11 10 9.0 (6.0) ○ △ 12 10 7. 5 (7.5) ○ △ 13 10 6.0 (9.0) ○ ○ 14 10 4.5 (10.5) ○ ○ 15-10.5 (5% solution 4.5) ○ ○ 16-9 0.0 (6.0) ○ △ 17-7.5 (7.5) ○ △ 18-6.0 (9.0) × × 19-4.5 (10.5) × × 20 10 10.5 (25% solution 4.5) ○ ○ 21 10 9.5 (6.0) ○ ○ 22 10 7.5 (7.5) ○ ○ 23 10 6.0 (9.0) ○ ○ 24 10 4. 5 (10.5) ○ ○ 25-10.5 (25% solution 4.5) ○ ○ 26-9.0 (6.0) ○ ○ 27-7.5 (7.5) ○ ○ 28-6 0.0 (9.0) ○ ○ 29-4.5 ( 10.5) △ ○ ○: No damage △: 1% or more damage ×: Hot Mostly damaged.

From the results in Table 5, it can be seen that the addition of slaked lime is effective as far as the mechanical impact resistance is concerned, and that if the temperature at the time of blending is high, the molded article immediately after molding has a slightly low impact resistance. Recognize.

[Test Examples 30 to 44] In order to examine the effect of the amount of alkali substance on impact resistance, 10% of incinerated ash A was used.
0.5 parts by weight of soda ash or 1. parts by weight with respect to 0 parts by weight.
The same test was conducted when 0 parts by weight were added.
Table 6 shows the mixing ratio and the results of the drop test.

Table 6 No. Slaked lime C heavy oil Water soda ash Room temperature drop test 70 ° C drop test 30 10 10.5 4.5-○ 31 10 9.0 6.0-○ 32 10 7.5 7.5 -○ △ 33 10 6.0 9.0-× × 34 10 4.5 4.5-× × 35 10 10.5 4.5 0.5 ○ ○ 36 10 9.0 6.0 0.5 △ 37 37 10 7.5 7.5 0.5 △ 38 38 10 6.0 9.0 0.5 △ 39 10 4.5 10.5 0.5 × × 40 10 10.5 4.5 1. 0 ○ 41 41 10 9.0 6.0 1.0 ○ 42 42 10 7.5 7.5 1.0 ○ 43 43 10 6.0 9.0 1.0 △ 44 44 10 4.5 10.5 1.0 × ○ addition of soda ash is effective for improving impact resistance, it is also seen that it is highly effective towards 1.0 part and 0.5 part.

Test Examples 45 to 93 As shown in Table 7, grease ("Kranox" Nippon Oil Co., Ltd., extremely high viscosity) was used to determine how the viscosity of oil affected the impact resistance. C weight (Kinematic viscosity at 40 ° C is about 300 cSt),
Tablets similar to those described above were prepared using mineral oil (various viscosities in the range of 100-320 cSt) and waste tempura oil (35 cSt) and tested for impact resistance to drop. The results are shown in Table 7 together with the conditions.

Table 7 Oil normal temperature drop test 70 ° C drop test No. Slaked lime Type Quantity Water Soda ash Ash A Ash C Ash A Ash C 45-Grease 15--○ ○ ○ ○ 46-C heavy oil 15--○ ○ × × 47 − Mineral oil 320 cSt 15 − − △ △ × × 48 − 220 15 − − × △ × × 49 − 150 15 − − × × × × 50 − 100 15 − − × × × × 51 − Tempura oil 15 − − × × × × 52 − Grease 96 − ○ ○ 53 − Heavy fuel oil 96 − − × 54 − Mineral oil 320 cSt 96 − △ × 55 − 220 96 − − × 56 − 150 96 96 − × × 57 − 100 96 − × × 58 − Tempura oil 96 − × × 59 10 Grease 15 − − ○ ○ 60 10 Heavy fuel oil 15 − − ○ × 61 10 Mineral oil 320 cSt 15 − − ○ × 62 10 220 15 − − △ × 63 10 150 15 − - △ × 64 10 100 15 - - × × 65 10 cooking oil 15 - - × × 66 10 grease 9 6 ○ ○ 67 10 C heavy oil 9 6 - ○ ○ 68 10 mineral oil 320cSt 9 6 - ○ △ 69 10 220 9 6 - ○ △ 70 10 150 9 6 - × × 71 10 100 9 6 - × × 72 10 cooking oil 9 6 -× × 73 10 Grease 15-1 ○ ○ ○ ○ 74 10 C heavy oil 15-1 ○ ○ × × 75 10 Mineral oil 320cSt 15-1 ○ ○ × × 76 10 220 15-1 ○ ○ × × 77 10 150 15- 1 △ ○ × × 78 10 100 15-1 × △ × × 79 10 Tempura oil 15-1 × × × × 80 10 Grease 144 1 ○ ○ ○ ○ 81 10 C heavy oil 144 1 ○ ○ ○ ○ 82 10 Mineral oil 320 cSt 1441 ○ ○ ○ ○ 83 10 220 1441 ○ ○ ○ ○ 84 10 150 1441 ○ ○ ○ ○ 85 10 100 144 1 × ○ × △ 86 10 Tempura oil 1441 × × × × 87 10 Grease 961 ○ ○ ○ ○ 88 10 C heavy oil 961 ○ ○ ○ 89 10 mineral oil 320cSt 9 6 1 ○ ○ ○ ○ 90 10 220 9 6 1 ○ ○ ○ ○ 91 10 150 9 6 1 △ ○ ○ × 92 10 100 9 6 1 × × ○ × 93 10 cooking oil 9 6 1 × × × × From these data, it is clear that the higher the viscosity of the oil, the better. It can also be seen that the effect increases when water is added, and that the addition of soda ash is effective.

[Test Examples 94 to 99] Nos. 91 to 9 in Table 7
For No. 3, the molding pressure was from 0.8 t / cm ² to 1.0 t / cm ²
Alternatively, the pressure was increased to 1.5 t / cm ² , and the tablet was molded and dropped again. The results are as shown in Table 8.

Table 8 No. Temperature Slaked lime Type Amount Water Soda ash Pressure (t / m ² ) Drop test 94 Room temperature 10 Mineral oil 150 cSt 9.6 11.5 ○ 95 Room temperature 10 Mineral oil 100 cSt 9 6 1 1.5 ○ 96 Room temperature 10 Tempura waste oil 9 6 1 1.0 △ 97 70 ° C 10 Mineral oil 150 cSt 9 6 1 1.5 ○ 98 70 ° C 10 Mineral oil 100 cSt 9 6 1 1.5 ○ 99 70 ° C 10 Tempura waste oil 9 6 1 1.5 × molding pressure It was found that a high tablet yielded a strong tablet even with low viscosity oil.

[Comparative Examples 1 to 5] For incinerated ash A,
3 parts by weight or 5 parts by weight of starch is mixed with 10 parts by weight of water in incinerated ash together with 100 parts by weight, and kneaded at room temperature or 70 ° C., and a molding pressure of 0.8 t / cm ² or 1.5
Molded into tablets at t / cm ² . For each tablet, a drop test was performed in the same manner as in the above test example. Table 9 shows the results.

Table 9 No. Starch water Molding temperature Molding pressure (t / m ² ) Drop test comparative example 13 10 Room temperature 0.8 △ 23 10 70 ° C 0.8 △ 35 10 Room temperature 0.8 ○ 45 10 70 ° C. 0.8 Δ5 3 10 room temperature 1.5 × starch was found to have the effect of imparting strength to the tablet at room temperature at low pressure molding.

[Test Examples 100 to 105 and Comparative Examples 6 to
8) In order to determine whether briquettes of incinerated ash can withstand the applied thermal shock when thrown into a high-temperature melting furnace,
For the three types of incinerated ashes A, B and C, tablets having the composition shown in Table 10 were produced at a molding pressure of 0.8 t / cm ² , and the tablets of the test example were prepared. Was placed in a furnace which had been heated to the temperature shown in FIG. For comparison, the same thermal shock test was performed on tablets manufactured in the same manner as in Comparative Examples 1 to 3 described above. Table 10 shows the results.

Table 10 Temperature (° C) No. Incinerated ash Slaked lime C heavy oil Water Soda ash 300 500 700 1000 Test example 100 A 100 10 961 ○ ○ ○ 101 101 B 100 10 996 1 ○ ○ 102 102 C 100 10 961 ○ ○ ○ 103 A 100 10 -10-○ ○ ○ 104 B 100 10 -10-○ ○ ○ 105 C 100 10 -10-○ ○ ○ 比較 Comparative Example 6 A 100 Starch 310- ○ × × 7 B 100 Starch 310-○ × × × 8 C 100 Starch 310-× × × ○ ：: Burned without collapse. X: Disintegrated powder immediately.

[0039]

According to the present invention, if the incinerated ash of waste, such as the incinerated ash of municipal solid waste and sewage sludge, is briquetted, the transportation and ash can be carried out immediately after briquetting and before being charged into a vertical melting furnace. Briquettes having sufficient strength for storage are obtained, and there is no need for a curing period. In the process from the briquetting to the introduction into the melting furnace, it is preferable to perform classification in order to avoid mixing of powder, but in practice, the amount of powder to be separated there and recirculated for briquetting is small, High product yield. There is virtually no powdering up to the melting furnace, and it withstands mechanical and thermal shocks when it is put into the furnace. Don't worry.

Among the raw materials used in the production, oil is an essential one, and various kinds of waste oils can be used, and even if they contain harmful substances such as heavy metals, they are used together with harmful substances in the incineration ash. Since it is detoxified and can be fixed in slag, it is also useful for simultaneous disposal of such waste.

In addition to the slaked lime used in a preferred embodiment, lime to be added for adjusting the basicity according to the components of the incinerated ash may be used therein, so that the amount of slag generated hardly increases. . When using an alkaline substance, an inexpensive material such as soda ash may be used.
In addition, since a small amount is sufficient, it does not cause a cost increase. Thus, briquetting of the incinerated ash according to the present invention can be performed at low cost.

[Brief description of the drawings]

FIG. 1 is a flowchart showing steps of a method for briquetting waste incineration ash of the present invention.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Takanobu Shiomachi 221-1-105 Tochimoto, Tanuma-cho, Anso-gun, Tochigi

Claims (5)

[Claims] 1. A method for briquetting waste incineration ash prior to melting it in a vertical melting furnace, comprising the steps of:
A method for briquetting waste incineration ash, comprising adding and mixing 1 to 20 parts by weight of oil with respect to 0 part by weight and briquetting the mixture by a briquetting machine. 2. A method of briquetting waste incineration ash prior to melting it in a vertical melting furnace, wherein the incineration ash is dried, and 1 to 20 parts by weight of oil is added to 100 parts by weight of the dried incineration ash. And 1 to 15 parts by weight of water and water, and the mixture is briquetted by a briquetting machine. 3. The briquetting method according to claim 1, wherein the incinerated ash is further added with 5 parts by weight or less of an alkali substance selected from sodium carbonate, sodium hydrogen carbonate and caustic soda. 4. The briquetting method according to claim 1, wherein slaked lime of up to 60 parts by weight is further added to the incinerated ash. 5. The method according to claim 1, wherein the oil is selected from mineral oil, vegetable oil, animal oil, grease, heavy oil, waste lubricating oil, waste industrial oil and waste edible oil. Briquetting method.