JPS58101798A - Dehydrating method for muddy material - Google Patents

Abstract

PURPOSE:To decrease moisture content down to levels at which self-burning is possible by adding dehydration aids to primarily dehydrated muddy-materials and granulating the same to suitable grain sizes and further subjecting the granules to secondary dehydration. CONSTITUTION:Muddy materials contg. org. components are dehydrated with dehydrators such as gravity dehydrators, vacuum dehydrators, centrifugal dehydrators, belt presses or filter presses down to about 82% moisture content. The primarily dehydrated sludge materials are charged into a rotary cylindrical mixer or the like and are crushed; at the same time dehydrating aids consisting of >=1 king among diatomaceous earth, slaked lime, calcium carbonate, incineration ashes, finely grained coal, sawdust, dry pulp and soil are added thereto; thereafter the mixture is granulated to suitable grain sizes. The dehydration (secondary dehydration) of the granules is performed with the above-mentioned dehydrators to reduce moixture content down to <=60%.

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 industry, 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 in the form of cellulose, and has a combustible content of 3000 to 4500 (Kcal
A.It has a calorific value of organic content) and is comparable to that of coal.Nevertheless, more than 90% of the total amount of sludge produced is 1, which ultimately relies on dumping into the earth or the ocean. There is,
However, untreated sludge contains a large amount of water and is highly salable.
Due to the foul odor it produces, there are restrictions on dumping due to environmental hygiene reasons, and large-scale disposal sites in and around large cities are now saturated.

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 kind of conditioning agent is added to the sludge, and after conditioning, equipment such as gravity dehydration, vacuum dehydration, centrifugal dehydration, belt press, Lyruta press, etc. is used alone or in combination. However, due to dehydration interference such as capillarity between water-containing powders and clogging of the i-cloth, the water content after dehydration was 70 to sag.
It has not been possible to dehydrate it to a state where self-combustion is possible in various incinerators, including multistage furnaces. 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% or less. For this reason, conventionally, after dehydration and solidification of muddy substances, drying is carried out in the sun or by circulation of combustion gas for the purpose of evaporating water.

However, the conventional method requires 30 to 401 parts of external fuel per %'ton of sludge cake, is uneconomical, and has 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, and then this is granulated to an appropriate particle size, and this granulated material is further dehydrated for a second time to reduce the water content to 60ts.
It is characterized by the following:

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

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

In the primary dehydration of the present invention, muddy materials containing organic components collected from waterways, rivers, sedimentation ponds, etc. are processed using a dehydrator such as gravity dehydration, vacuum dehydration, centrifugal dehydration, belt press, or filter press. Reduce moisture content to below 82-. Here, it is preferably 82% to 75%. For example, if you use a belt press, 2 to 3 kli/
With an operating pressure of DI, it is possible to dehydrate up to a moisture content of 75% by gravity and squeezing action, and a centrifugal dehydrator can dewater up to 2000~30% water content.
It is possible to dehydrate to the same water content <751 by centrifugal force at an operating pressure of 00G. However, what you should be careful about here is to choose an appropriate operating pressure for each dehydrator. However, unnecessarily increasing the operating pressure will promote the compaction of sludge, which will have the opposite effect, such as making it impossible to drain water and clogging the f-cloth.

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 lO to 100 g based on the dry weight of the original sludge solids, and then granulated to an appropriate particle size. Among the dehydration aids, incineration ash is relatively easy to obtain, such as sewage treatment sludge ash, bed urine treatment sludge ash, industrial wastewater treatment sludge ash, municipal waste incineration ash, and industrial waste incineration ash. It is desirable to use materials with low reuse value. 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 type, a scree set, or a vibrating type, so that the drying aid mentioned above does not sink into the sludge, and
Knead as if stirring. The particle size after granulation should be 20 degrees or less in diameter, especially 7096 in weight ratio for suspensions with a diameter of 1 to 1 degrees.
It is desirable that the above particles are distributed.

When the sludge material is granulated after adding the dewatering aid as in this invention, the dewatering aid is uniformly mixed into the sludge material.

This granular sludge material is again dehydrated (
By performing secondary dehydration, the water content can be reduced to 60 inches or less, and the capacity can be reduced to 50% or less compared to the initial one. In addition, this secondary dehydration is carried out 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.

Initial pressure is less than 30kg/d, preferably 15-25kg
/cdL, and the time is preferably 2 minutes or less. The main pressurization is performed at 50 to 100 #I/cri, preferably 60 to 80 #/d, for 1 to 3 minutes.

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

It contains organic matter that has settled and concentrated in waterways, rivers, sedimentation ponds, etc., and has a water content of 98%, and is collected by a mud pump and supplied to a belt press. At this time, the water content of the muddy material B was approximately 96%, as the water content decreased slightly during the collection.

This muddy substance B is subjected to primary dehydration using a belt press.
A solid mud-like substance C condensed into a disk shape of 10 mm or less in thickness is taken out by pressure dehydration.

This solid slurry material C, which has been added to the incinerated ash in the incinerator in a range from O to j00%, is crushed in a rotary cylindrical mixer and blended. The crosstalk time is about 20 to 40 seconds. During this time, the muddy material C is divided into quarters and 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 grainy outer layer and having a diameter of 5 cm or less.

This granular slurry material is placed in a pressing device for secondary dehydration, and a pressing operation is performed by applying a pressure of 20#/d for 1 minute at the beginning. Thereafter, the pressure was increased to 70#/('d) for 2 minutes. Through this operation, the granular mud material became mud material E with extremely low water content.

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

The 969G water-containing mud material B may be formed into a 70% water-containing mud material B' using a filter press, and the amount of incineration ash added in the mixer may be set to 301 or less to facilitate compression dehydration.

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

FIG. 1 shows the relationship between the amount of incinerated ash added and the water content of the dehydrated sludge material when incinerated ash is added as a dehydration aid to the secondary dehydrated cake and mixed and granulated for secondary dehydration.

From this figure, as shown in graph a, when the water content before secondary dehydration is 98 cm, the water content after secondary dehydration remains constant until the amount of cooling of the dehydration aid reaches 100% or more, and then suddenly and stabilized at 15,096th place.

This moisture content was 40%. Next, when the water content before secondary dehydration is 8096 (graph B), the water content after secondary dehydration is 4096 when the amount of dehydration aid added is 30 inches or less.
It became. When the amount of dehydration aid is 30 to 50, the water content after secondary dehydration is stabilized. Next, the moisture content before secondary dehydration is 75%.
In the case of (graph C), almost the same progress as in the case of water content of 5 ots is followed, but it can be seen that the water content drops to 40 oz with the addition of auxiliary agent of 20 oz.

As you can see from the above, the drying aid is 130% in both cases.
% or more, the water content will be 60- or less.

However, if the water content before secondary dehydration is 98-1, it is 1501
Unless the above drying aid is added, the moisture content will not be lower than 50%. On the other hand, for 80% and -75%, the water content can reach 40% by simply adding 20 grams of dehydration aid. In this way, it is desirable to reduce water as much as possible through primary dehydration.1. is 82, considering the functions of a normal dehydrator.
-The following is considered sufficient. With this water content, the dehydration aid can 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 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 cm and 751 cm, respectively.
3091i, and FIG. 2 shows a comparison of their weights. For example, if the total weight of sludge with 98% water content is 1 kg at the beginning, after the second dewatering, the water content is 751, which is 80 g, and after the second dewatering, the weight of 10 g of the dehydrating agent is added. Moisture 30%
This reduces the total weight to 42g. Comparing the water content weights, the weights decrease to 980g, 60g, and 12g, respectively. The sludge material subjected to secondary dewatering in this manner has a water content of 50 to 50.

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 Figure 81, the sludge solids 1 are composed of sludge solids 12, interstitial water 131, capillary rising water 14, surface adhesion water 15, one internal water, and surrounding free water 17; everything except the sludge solids water, and of the above water, internal water 16
It exists inside the solid content 12 and has a strong binding force and is compressible, so it is difficult to dehydrate it mechanically. 15 etc.) can be relatively easily dehydrated by adding a dehydration aid or mechanical dehydration.

After the secondary dewatering, the sludge solids 12 and the sludge solids 12 are deformed into a flat shape (as shown in Figure b1), and the internal water 16
It is assumed that most of the bound water other than the above is excluded.

The above results are obtained because the drying aid 18 added before the secondary dehydration adheres to the outer skin of the patterned material.
First, the affinity of the water 15 adhering to the surface weakens, and then a squeezing action is added, crushing the outer skin of the granular muddy material, and at the same time crushing the sludge solids, and the bound water, etc., which has no place to escape, passes through the gaps between the grains to the outside. This is thought to be because the water is drained away.

Finally, FIG. 4 shows the moisture content of sludge materials in the conventional dewatering method and the dewatering method according to the present invention, and the thermal characteristics in each water content state. As shown in this figure, in the current multistage furnace, in order to dry the sludge material to the self-combustion range, 30 to 40 liters of external combustion fuel is consumed per 1 ton of sludge cake. Therefore, increasing the level of self-combustion in various incinerators has been considered, but it is difficult to create incinerators that can self-combust when the water content is 65 Is or more. By the dewatering method of the present invention, the moisture content of sludge is reduced to 60% or less, preferably 50% or less, so that it is not only possible to burn the sludge as it is, but also to generate energy.

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 capacity 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 materials 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 drawings]

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 between the initial sludge material, after secondary dewatering, and after secondary dewatering. Figure 3 is an imagined organization diagram of sludge material before dewatering and after secondary dewatering, and Figures 4 (a) and (b) show the water content of sludge material in the conventional dewatering method and the dewatering method according to the present invention. , and thermal characteristics in each water-containing state. 1...Sludge substance 12...Sludge solid substance 13...
Pore water 614...Capillary rising water 15...Surface adhesion water Figure 3 (a) De-icing @ (b) After secondary de-lking Figure 4 Person performing supplementary Figure 11 1', U,',, 1SO8+ Hitachi Metals Co., Ltd. 10 Norio Kono Yoshihiro 1,: 14 "Detailed explanation of the invention in the subject specification of Supplement + E, 2-1-2 Marunouchi, Chiyoguchi 1-ku, Tokyo. Contents of the amendment "Invention The contents of "Detailed explanation of" have been amended as follows. L Page 9 Line S This solid muddy powder 1 is completely burnt +++
, IL line 9177 as a dehydration aid for addition. & Page 10, lines 4 to 6, 30- or less, 4041
0 Summer Line 11 Both are dehydration aid & 10 Tei Line 14 Add dehydration aid of 11sO% or more a Page 18 Line 8 Addition of dehydration aid or mechanical dehydration?
After the secondary dehydration from line 1ljjlo to line 11, the weight of the dehydration aid lO9 is greater than

Claims (1)

[Claims] 1. After dehydrating the muddy material and adding a dehydration aid to the dehydrated muddy material, this is granulated to an appropriate particle size, and then the granulated material is By performing secondary dehydration, the moisture content can be reduced to 60
A method for dehydrating muddy substances characterized by reducing the amount to 1 g or less. 2. A method for dehydrating a muddy material according to claim 1, characterized in that the secondary dehydration is performed under pressure to reduce the water content to 50% 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. Claims 1 to 3 provide 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 the dehydration aid. Characteristic dehydration method for muddy substances. 5.% Permissible A method for dehydrating a muddy substance according to claim 4, characterized in that incineration ash is used. 6. According to claim 5, the incinerated ash is any one of sewage treatment sludge ash, urine treatment sludge ash, industrial wastewater treatment sludge ash, municipal garbage incineration ash, and industrial waste incineration ash. A method for dewatering muddy substances characterized by using a mixture thereof. 7. A method for dewatering mud-like substances according to claim 1, characterized in that the amount of the dewatering aid added is 10 to 1009 G based on the dry weight of the original mud sludge solids. 8. A method for dewatering a slurry material according to claim 1, characterized in that the particle size after granulation is 201EII or less in diameter. 9. A method for dewatering a muddy substance according to claim 8, characterized in that particles having a weight ratio of 701 or more are distributed in a particle size band having a diameter of 1 to 1°. 10. Percentage of sludge according to claim 2, characterized in that the pressurization method is direct pressurization or indirect pressurization using either a vertical or horizontal dehydrator, and two-stage compression in which pressurization is applied after initial pressurization. Methods of dehydrating substances. 11. In claim 2, the pressurizing force and its holding time are characterized in that the initial pressure is 30 Jl/cr/ or less for 2 minutes or less, and the pressurizing is 50 to 100 kg/cII for 1 to 3 minutes. A method for dehydrating muddy substances.