JPS58101797A - Dehydrating method for muddy material - Google Patents

Abstract

PURPOSE:To decrease moisture content down to levels at which self-burning is possible by adding dehydrating aids to primarily dehydrated muddy-like materials, granulating the same to suitable grain sizes and subjecting the granules to secondary dehydration. CONSTITUTION:Muddy-materials contg. org. components are dehydrated down to about 82% moisture content with dehydrators such as gravity dehydrators, vacuum dehydrators, centrifugal dehydrators, belt presses or filter presses. The primarily dehydrated materials are charged into a rotary cylindrical mixer or the like and are crushed; at the same time >=1 kind among diatomaceous earth, slaked lime, calcium carbonate, incineration ashes, finely grained coal, sawdust, dry pulp and soil are added thereto as dehydrating aids. In this case, the aids are added at 10-100wt% based on the dry weight of the original sludge solids and the mixture is rolled to granulate the same to suitable grain sizes. Thereafter the tranules are dehydrated (secondary dehydration) with the above-described dehydrators down to <=60% moisture content.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for dewatering muddy water materials with high water content, such as sewage sludge.

Currently, with the enhancement of water quality in public water bodies and the development and transformation of the industrial world, the amount of water purification is increasing, and as a result, the amount of sludge as a byproduct is steadily increasing. Generally, the combustible content of organic sludge is
Shows cellulose form, 3000-4500 (KCal
/ has a calorific value of 9@organic content), comparable to coal.
Despite this, 90% of the total amount of sludge generated
The above methods ultimately rely on dumping into the ground or the ocean. However, because untreated sludge contains a large amount of water, is putrefactive, and produces a foul odor, there are restrictions on dumping it for environmental hygiene reasons, and land disposal sites in large cities and surrounding cities11 have now reached saturation. .

Therefore, when it comes to processing and disposing of sludge materials, effective use and reuse are being advocated from the perspective of resource conservation, and both local governments and manufacturers are working hard to develop such methods, but there is no definitive solution yet. Conventionally, in order to dehydrate and solidify sludge containing organic components, some type of conditioning agent is added to the sludge, and after conditioning, gravity dehydration, vacuum dehydration, centrifugal dehydration, belt press muffler dehydration, etc. are performed independently. Alternatively, dehydration and solidification were performed in combination, but due to dehydration interference such as capillarity between water-containing powders and clogging of the three cloths, the moisture content after dehydration was in the 70 to 80% range, and a multi-stage furnace was used. It was not possible to dehydrate the water to a state where it could be self-combusted in various incinerators such as . Dehydration of muddy substances to the self-combustible range is also important from the perspective of resource conservation. Here, the moisture content in the self-combustion region needs to be about 65 inches or less. Therefore, conventionally, after dehydrating and assimilating muddy materials, drying is carried out in the sun or by circulation of combustion gas for the purpose of evaporating water. However, in the conventional method, the sludge removal rate, t
It required 30 to 401 external fuel per turn, which was uneconomical and caused many problems in terms of equipment.

The present invention solves the above-mentioned problems and provides a dewatering method that can reduce the moisture content until self-combustion is possible, and furthermore, can dewater the sludge material until energy can be produced.

Therefore, in the dehydration method of the present invention, a dehydration aid is added to the dehydrated slurry material, granulated to an appropriate particle size, and the granulated material is further dehydrated to reduce the water content to 60% or less. It is characterized by:

In a preferred implementation of the present invention, secondary dehydration is performed under pressure to reduce the water content to 50% or less.

The present invention will be explained in detail step by step.

In the primary dewatering process 2 of the present invention, muddy materials containing organic components collected from waterways, rivers, sedimentation ponds, etc. are processed into muddy form using a dewatering machine such as gravity dehydration, vacuum dehydration, centrifugal dehydration, belt press, or filter press. Reduce the moisture content of the material to below 82-. The moisture content is preferably 82% to 75%.

For example, if you use a belt press, it will weigh 2 to 3 kg/c.
At an operating pressure of Id, gravity and squeezing action can dehydrate up to a water content of 75 eIb, and a centrifugal dehydrator can dehydrate up to 2000 eIb.
At an operating pressure of ~3,000 G, centrifugal force can dehydrate the water up to a water content of 75°. However, care should be taken here to select an appropriate operating pressure for each dehydrator. However, unnecessarily increasing the operating pressure will promote compaction of the sludge, which will lead to no way to drain water, and even cause clogging of the r-cloth, which will have the opposite effect.

The sludge that has been primarily dehydrated in this way is put into a rotary cylindrical mixer, etc., and crushed, and at least one of diatomaceous earth, slaked coal, calcium carbonate, incinerated ash, pulverized coal, sawdust, dried pulp, and soil is used as a dehydration aid. is added in an amount of 10 to 100 g based on the dry weight of the original sludge solids. Among the dehydration aids, incineration ash is relatively easy to obtain, such as sewage treatment sludge ash, urine treatment sludge ash, industrial wastewater treatment sludge ash, municipal waste incineration ash, industrial waste incineration ash, etc., and has industrial reuse value. It is desirable to use a thin one. In particular, it is most desirable to circulate and use a portion of the incineration ash produced by incinerating the dehydrated product produced in the practice of the present invention.

The granulation method uses a mixer such as a rotary set, a screw set, or a vibrating mixer, and mixes the above-mentioned drying aid so that it does not sink into the sludge and excavates it, and the particle size after granulation is adjusted to the diameter. 20w
The weight ratio should be 7 or less, especially if the diameter is in the range of 1 to 10 mm.
It is desirable that 0% or more of the particles are distributed.

By dewatering this granular sludge again using the dewatering machine ('secondary dehydration), the water content can be reduced to 60% or less, and its capacity can be reduced to 50% or less compared to the initial one. In addition, this secondary dehydration is performed by compression, and the initial pressure and pressurization are performed separately, and by performing two-stage compression, the water content is reduced to 50% or less, and the volume is reduced to 60% or less. .

This initial pressure is 301c! ? /crl or less, preferably 15
It is desirable that the amount is 25 kg/cI/l and the time is 2 minutes or less. The main pressure is 50 to 100 #/d, preferably 59 to 80 #/CI! t and squeeze for 1 to 3 minutes.

Next, the present invention will be explained in detail based on experimental examples.

Sludge containing concentrated organic matter and having a moisture content of approximately 98 cm is collected by a pump and supplied to a belt press. At this time, the water content of the muddy material B was approximately 96 cm, as the water content decreased slightly during the collection.

This muddy substance B is subjected to primary dehydration using a belt press.
It was dehydrated under pressure and condensed into a disk shape with a thickness of IQIIm or less. Take out the solid mud substance C.

This solid mud substance C is crushed in a rotating cylindrical mixer, and the incinerated ash in the incinerator is added in a range of 200% from O, and the mixing time for blending is about 20 to 40 seconds. be. During this time, the muddy material C is divided into quarters each time it is turned over in the mixer, mixed with the incinerated ash, and rolled, resulting in a granular muddy material having a dry outer shell and having a diameter of 511I or less.

This granular slurry material is collected in a pressing device for secondary dehydration, and a pressing operation is performed by initially applying a pressure of 20Ac9/d for 1 minute. Then pressurize and apply 70 liters of pressure for 2 minutes. Through this operation, the granular mud material becomes mud material E with extremely low water content.

Furthermore, this muddy substance E is crushed by a crusher to form a solid muddy powder F. This solidified muddy powder F is completely burned in an incinerator, and a part of the resulting incinerated ash is used for addition. It can also be recycled back into the mixer as a drying aid.

In addition, the above-mentioned 96-chi water-containing muddy substance B was formed into a 70-chi water-containing muddy substance B using a filter press, and the amount of incineration ash added in the mixer was set to 30% or less to facilitate compression dehydration. It's okay.

Next, the experimental results of this experiment will be explained.

Figure 1 shows the relationship between the amount of cooling of incinerated ash and the water content of dehydrated sludge material when incinerated ash is added as a dehydration aid to the secondary dehydrated cake, mixed and granulated for secondary dehydration. , gura→a
As shown in Figure 2, when the water content before secondary dehydration is 68%, the water content after secondary dehydration remains constant until the amount of dehydration aid added exceeds 100%, and then rapidly decreases to around 150%. becomes stable.

This water content was 4 (l).Next, when the water content before secondary dehydration was 80% (graph b), the water content after secondary dehydration was 40%.
It became chi. When the amount of dehydration aid is 30-10%, the water content after secondary dehydration is stabilized. Next, the water content before secondary dehydration is 7
In the case of 5 inches (graph C), the process is almost the same as in the case of 80 inches of water content, but it can be seen that when the amount of additive is 20 inches, the water content drops to 40 inches.

As you can see from the above, the drying aid is 130% in both cases.
If more than 50% of water is added, the water content will be less than 60%.

However, if the water content before secondary dehydration is 98 cm, it is 1501
Unless the above-mentioned drying aid is added, the moisture content will not be lower than 50%. 'On the other hand, in the case of 80175%, the water content can reach as much as 40 g by simply adding 2 (l) of dehydration aid.In this way, it is desirable to reduce the water content as much as possible in the primary dehydration. Considering the functions of a normal dehydrator, 82-
The following is considered sufficient. With this water content,
A dehydration aid may be attached to the surface of the granulated powder.

If the water content is higher than this, the dehydration aid will be consumed during granulation and reduce the water content, so a large amount of the aid will be required.

Next, in this experiment, the conditions of the initial sludge material, the sludge material after the primary dewatering, and the sludge material after the secondary dewatering had a water content of 98% and 7%, respectively.
51 and 30%. FIG. 2 shows a comparison of the weights of these. For example, if the total weight of sludge with a water content of 98 g is initially 1ic9, after the second dehydration it becomes 80 g, which is 1/13 of the case where the water content is 75%, and after the second dehydration, the weight of the dehydrating agent is 10 g. Even if added, moisture 3
09g, the total weight is reduced to 42g. Comparing the water content weights, the weights decrease to 980g, 60g, and 12g, respectively.

The sludge material secondary-dehydrated in this way has a moisture content of 50 to 6.
(Since it is less than 1 liter, it becomes solid and has no surface moisture and has a weight of 2000 to 2500 Kcal 7 kg (7
) It has a calorific value.

Next, Figure 3 (a) shows the granular muddy material before the -th dehydration (b).
) is an imagined organization diagram of the combustible mud material after secondary dehydration.

In the figure (a), a bay-shaped substance 1 is composed of sludge solids 12, pore water 13, capillary rising water 14, surface adhesion water 15, internal water 1ii and surrounding free water 17,
Everything except solid sludge is water. Of the above-mentioned water, only internal water 16 exists inside the solid content 12 and has a strong binding force and is compressible, so it is difficult to mechanically remove water, but other water (pore water 13, capillary rising water
It is thought that the water adhering to the surface (15, etc.) can be relatively easily dehydrated by adding a dehydration aid or by mechanical dehydration. And the bay-shaped substance after secondary dehydration is (b)
As shown in the figure, it is assumed that both the sludge solids 12 are deformed into a flat shape, and that most of the bound water other than the internal water 16 is excluded.

The reason why the above results are obtained is that when the drying aid 1 added before secondary dehydration adheres to the outer skin of the dirt, the affinity of the surface adhering water 15 is first weakened, and then a squeezing action is added, causing the granular mud to become It is thought that this is because the outer shell of the sludge material is crushed and the solid sludge is crushed at the same time, and the bound water, etc., which has no place to escape, is drained to the outside through the voids between the particles.

Finally, FIG. 4 shows the moisture content of sludge materials in the conventional dehydration method and the dehydration method according to the present invention, and the thermal characteristics in each moisture content state. As shown in this figure, in the current multi-stage furnace, in order to dry the sludge material to the self-combustion range, the external combustion fuel is used at 30 to 40 kg per ton of sludge cake! is also spent.

Therefore, increasing the self-combustion level in various incinerators is being considered, but water-containing Cm6. ,．． 5'4 or more, it is difficult to build a self-combustible incinerator. By the dewatering method of the present invention, the moisture content of sludge is reduced to 60% or less, preferably 5% or less, so it is not only possible to burn the sludge as it is, but also to create energy. be.

As explained above, the present invention has succeeded in reducing the water content to a point where self-combustion is possible without wasting the high thermal properties of sludge containing organic components, and in addition, the sludge after dewatering has The volume of the substance was reduced to less than 50%. Additionally, the heat generated during combustion can be used to convert it into useful energy such as power generation.

As described above, the present invention is a very effective method for dewatering sludge substances in these days when there is a demand for effective use and reuse of industrial waste from the viewpoint of resource conservation.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the amount of incinerated ash added and the water content of dehydrated sludge material, and Figure 2 shows the weight ratio of water and sludge solids in the initial sludge material, after secondary dewatering, and after secondary dewatering. Figure 3 shows the imagined organization of the sludge material before dehydration and after secondary dehydration, and Figures 4 (a) and (b) show the water content of the sludge material in the conventional dehydration method and the dehydration method according to the present invention. FIG. 3 is a diagram showing thermal characteristics in each water-containing state. 1...Sludge substance 12...Sludge solid substance 13...
Pore water 14...Capillary rising water 15...Surface adhesion water 1
6...Internal water 17...Free water 18...Drying aid supplement Figure 3 (a) Before dehydration (6) After secondary dehydration Figure 4 Procedure amendment (voluntary) 57, 9.20 Showa year J I+ ・1 list (i (+) non-show 11
1156 fl-Request for permission No. 183490 Straddle i Yu 1
1 150g+, 1.11'/, Remaining Co., Ltd. Non/+I III Norio Yoro Person 1: III Higashi S; (Miyakochiyo Il1 Ward Marunouchi 2
Beak of the detailed explanation of the invention in the λ・1 elephant specification of Chome 1 Tsuri 2 Soi Yu 11. The content of the amendment "Detailed Description of the Invention" is revised as follows. 'L, page 5 line 18 Moisture content '1-50j or less and L 0
2, 8jj line 15 has agglomeration, solid muddy substance 0&
Line 9N9 Burn this solid muddy powder 1 4 1ajjl
Line 1 As a dehydration aid for addition 4 σ Page 16 Lines Supervise, facilitate press dehydration & 10 lines 7-8
30'% or less, 40% - 9, 10 pages line 15 All dehydration aids a io page 18 line 150% or more 1L
9. Add the weight of the dehydration aid xo9 on page 11, line 16, and add the weight of the dehydration aid xo9.

Claims (1)

[Scope of Claims] 1. In the dehydration of muddy materials, a dehydration aid is added to the dehydrated muddy material, the granules are granulated to an appropriate particle size, and the granulated material is subjected to secondary dehydration to reduce water content. A method for dehydrating muddy substances, characterized by reducing the water content to 60% or less. 2. A method for dehydrating a muddy material, as set forth in claim 1, characterized in that secondary dehydration is performed under pressure to reduce the water content to 501 or less. 3. A method for dehydrating a muddy material according to claim 1 or 2, characterized in that the water content of the muddy material is reduced to 82 cm or less in the second dehydration. 4. Permissible claims In items 1 to 3, it is specified that one or more of diatomaceous earth, slaked lime, calcium carbonate, incinerated ash, pulverized coal soil, bone meal, sawdust, and dried pulp is used as a dehydration aid. Characteristic dehydration method for muddy substances. 5. A method for dehydrating muddy substances according to claim 4, characterized in that incineration ash is used. 6. In claim 5, the incineration ash includes sewage treatment sludge ash, urine collection treatment sludge ash, industrial wastewater treatment sludge ash,
A method for dewatering muddy substances, characterized by using either municipal waste incineration ash, industrial waste incineration ash, or a mixture thereof. 7. A method for dewatering sludge as set forth in claim 1, characterized in that the amount of the dewatering aid added is 10 to 100 g based on the dry weight of the original sludge solid content. 8. A method for dewatering a slurry material according to claim 1, characterized in that the particle size after granulation is 20 u or less in diameter. 9. A method for dewatering a muddy substance according to claim 8, characterized in that 70% or more of the particles by weight are distributed in a particle size range of 1 to 10 mm in diameter. 10. Claim 2 is characterized in that the pressurization method is direct pressurization or indirect pressurization using either a vertical or horizontal dehydrator, and two-stage compression is performed in which pressurization is applied after initial pressure. Method for dewatering muddy substances. 11. In claim 2, the initial pressure is 30 sens d or less and the initial pressure is 2 minutes or less, and the pressurization is 50 ~
A method for dehydrating muddy substances, characterized by dehydrating 109 kg/Cd for 1 to 3 minutes. 12. In claim 1, the slurry material is primarily dehydrated to a water content of 82 or less, and incineration ash is added to the mud material in an amount of 10 to 50% based on the dry weight of the original sludge solid content. ,
The granules are granulated so that particles with a weight ratio of 70 mm or more are distributed in a particle size band with a diameter of 1 to 101,131 mm, and the granules are then compressed and dehydrated to an initial pressure of 15 to 25 JC9/(: 2 in d). 1. A method for dehydrating a muddy substance, characterized in that compression is carried out at a pressure of 60 to 80 minutes and 9/d for 1 to 3 minutes.