JP2003334599A - Dehydration and drying method for slurry - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dehydration and drying method for a slurry capable of efficiently excluding/reducing moisture by a reduced quantity of energy. <P>SOLUTION: In the dehydration and drying method for the slurry, the moisture of the slurry 1 in a dehydration and drying process is excluded by the gravitational action on moisture and the forcible passage of air through the slurry without using pressurization or compression in a dehydration and drying apparatus 2 and, in order to renew the surface of the slurry and to expand the surface area of the slurry, the slurry is continuously loosened or loosened and crushed by rollers provided under a substrate 3 and/or a screw (not shown in Fig) provided above the substrate 3 so as to obtain strength not showing a lumpy state. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dehydrating and drying a slurry for removing water from the slurry.

[0002]

2. Description of the Related Art Methods for dewatering slurries produced from industrial activities and sewage / wastewater treatment are known to be methods such as pressurization, squeezing, filtration by suction, compression separation by centrifugal force, and the like. The water content of the dehydrated cake thus obtained is about 75 to 85% by weight in the case of an organic slurry. Further, in order to reduce this high water content, further drying is required, and for the drying, indirect drying with a heat source or direct drying is performed. However, conventionally, these dehydration and drying are performed separately and independently, and in this case, a dehydration method and a drying method that are suited to the properties and characteristics of the slurry are not used, and energy and economical efficiency are not achieved. It was bad.

[0003]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for dehydrating and drying a slurry which can efficiently remove and reduce water with a small amount of energy.

[0004]

Means for Solving the Problems As a result of diligent studies, the present inventor has found that one device has a function of dehydration and drying as will be described later.
The present inventors have obtained the knowledge that water can be efficiently removed with a small amount of energy by providing a mechanism, and have arrived at the present invention.

That is, according to the first aspect of the present invention, the water content of the slurry in the dehydration and drying process is eliminated by gravity action on the water content and forced aeration in the slurry instead of pressurization or compression, and the surface of the slurry is renewed. This is a method for dehydration and drying of a slurry, characterized by performing continuous disentangling of a strength not exhibiting lumps or disintegrating and disintegrating to expand the surface area. The invention of claim 2 is the method of dehydrating and drying a slurry according to the invention of claim 1, wherein heated air, waste heat gas or dehumidified air is used for forced aeration in order to promote evaporation of water to be removed. A third aspect of the present invention is the method for dehydrating and drying a slurry according to the first aspect of the present invention, wherein warm air or waste heat gas is used for forced aeration in order to promote a decrease in viscosity and evaporation of removed water. In the invention of claim 4, in any one of the inventions of claims 1 to 3, in order to enhance the gas renewal in contact with the surface of the slurry, the gas flow velocity near the gas-solid interface between the slurry and the gas is forcibly increased. This is a method for dehydrating and drying a slurry that creates an environment. A fifth aspect of the present invention is the method for dehydrating and drying a slurry according to any one of the first to fourth aspects, in which the slurry to be dehydrated and dried is heated in advance in order to promote a decrease in viscosity and evaporation of the removed water.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. FIG. 1 is a schematic cross-sectional view of a dehydration / drying apparatus for explaining the forced ventilation method. In FIG. 1, dewatering and drying device 2
Inside, a slurry 1 containing water is deposited on a substrate 3. The base 3 is made of a material such as a breathable film or net, and the lower side of the base 3 is sucked by a pump or a fan to have a weak negative pressure. Gas such as waste heat gas or the like is forcibly supplied, the water drops along with the gas passing through the slurry 1 below the base 3, and a large amount of water vapor is also sucked below the base 3. At this time, the difference between the pressure below the substrate 3 and the pressure above the slurry is preferably about 0.001 to 0.01 MPa. Further, for example, a roller 4 is provided below the base 3, and the rotation and movement of the roller 4 and the movement of the base 3 on the roller 4 cause the base 3 to vibrate lightly as shown in FIG. The slurry 1 in the form of lumps on the base 3 is loosened.

FIG. 3 is a diagram showing an example of a method for loosening and crushing slurry by a screw. In FIG. 3, a screw 5 is provided above the base plate 3,
The screw 5 is buried in the accumulated slurry 1, and when the screw 5 rotates, the slurry 1 is loosened and crushed as the screw 5 rotates. As the screw 5, FIG.
3A may be provided with spiral disk-shaped blades, or may be provided with blade-shaped blades as shown in FIG. 3B. Further, a roller may be provided below the base and a screw may be provided above the base to loosen and crush the slurry. As described above, when the lumped slurry on the substrate is loosened or loosened / crushed, the surface of the slurry in contact with the gas is renewed, and the surface area is increased, so that the water removal effect is enhanced. .

As a gas supplied for drying the slurry, it is preferable to use warm air, waste heat gas or dehumidified air in order to promote evaporation of water to be removed, and particularly, viscosity of water to be removed. In order to promote the reduction and evaporation, it is preferable to use warm air or waste heat gas.

Further, gas such as air and waste heat gas is forcibly supplied onto the slurry 1 by a weak negative pressure below the substrate 3, in order to enhance the renewal of gas contacting the slurry surface at that time. In addition, as shown in FIG. 4, it is preferable to create an environment in which the gas flow velocity near the gas-solid interface between the slurry and gas is forcibly increased, and the strength of the wind supplied at this time is such that the petals and confetti soar. Is preferred. Also,
It is preferable to preheat the slurry to be dehydrated and dried in order to accelerate the decrease in the viscosity and the evaporation of the removed water.

As described above, in the present invention, the slurry is subjected to continuous loosening, or loosening and crushing, so that the slurry does not form a lump by the roller or screw, and the water content in the slurry is efficiently fed by gravity and forced aeration. Will be eliminated. Further, by using warm air, waste heat gas or dehumidified air for forced ventilation, preheating the slurry, or increasing the gas flow velocity on the slurry surface, the efficiency of water removal can be further enhanced. INDUSTRIAL APPLICABILITY The present invention can be applied regardless of the type or property of the slurry, and since the dehydrating and drying functions / mechanisms are provided in one device, it is possible to efficiently remove water with a small amount of energy.

[0011]

According to the present invention, the water in the slurry can be efficiently removed with a small amount of energy. Further, according to the present invention, since a slurry having a significantly reduced water content can be obtained, the amount of waste at the time of disposing of the slurry can be significantly reduced, and the processing and reforming for recycling can be facilitated and the community Can be supplied to and returned to. Furthermore, the manifestation of these effects also contributes to the solution of global environmental problems.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a dehydration / drying device for explaining a forced ventilation method of the present invention.

FIG. 2 is a diagram showing an example of a method for loosening slurry by a roller.

FIG. 3 shows an example of a method for loosening and disintegrating a slurry with a screw. (A) shows a disk-shaped blade provided as a screw, and (b) shows a blade-shaped one provided as a screw. FIG.

FIG. 4 is a diagram showing an example of a state in which the gas flow velocity near the gas-solid interface is forcibly increased.

[Explanation of symbols]

1 slurry 2 Dehydrator / dryer 3 foundation 4 roller 5 screws

Claims (5)

[Claims] 1. The water in the slurry being dehydrated and dried is removed by gravity action on the water and forced aeration in the slurry instead of pressurization or compression, and at the same time, the lumps are formed to renew the surface of the slurry and expand the surface area. A method for dewatering and drying a slurry, characterized in that continuous disintegration having a strength not exhibiting, or disintegration and disintegration is performed. 2. The method for dehydrating and drying a slurry according to claim 1, wherein warm air, waste heat gas or dehumidified air is used for forced aeration in order to promote evaporation of water to be eliminated. 3. The method for dehydrating and drying a slurry according to claim 1, wherein warm air or waste heat gas is used for forced aeration in order to promote reduction in viscosity and evaporation of water to be eliminated. 4. An environment in which the gas flow velocity near the gas-solid interface between the slurry and the gas is forcibly increased in order to enhance the renewal of the gas in contact with the surface of the slurry. Method for dehydration and drying of slurry of. 5. The method for dehydrating and drying a slurry according to any one of claims 1 to 4, wherein the slurry to be dehydrated and dried is heated in advance in order to promote a decrease in the viscosity of the removed water and evaporation.