KR20190115626A - Sludge Drying Method and Device Using Conductive Heat Energy - Google Patents

Abstract

The present invention relates to a sludge drying method for treating food waste, livestock excretions and a large amount of sludge generated in the industrial production process. According to the present invention, a method for drying sludge by using conductive thermal energy comprises the steps of: mixing sludge with a plurality of metal-pretreated materials including at least one of aluminum, iron and copper and having sizes different from each other; injecting high temperature dry air into sludge having the metal-pretreated materials mixed therewith; vibrating a dryer to allow the sludge and the metal-pretreated materials to be collided with each other; injecting high temperature dry air into the sludge and the metal-pretreated materials which have been collided with each other; discharging the sludge and the metal-pretreated materials; and separating the metal-pretreated materials from the dried sludge. According to the present invention, the method can complement convection heat and radiant heat through conductive heat of metal materials injected into sludge, increases an effect of raising the temperature of drying objects from a heat source positioned in the upper part, and can shorten drying time and increase drying effect by sequentially transferring the drying objects. Further, the method can increase drying effect by circulating a large amount of dry external air into a drying chamber, thereby rapidly evaporating water of the drying objects.

Description

Sludge drying method and device using conducting heat energy {OMITTED}

The present invention relates to a sludge drying method and apparatus using not only convective heat energy and radiant heat energy but also conductive heat energy.

Due to industrial development and urban concentration, wastes containing a large amount of water (hereinafter referred to as sludge) are generated in large quantities, and many problems are generated in the treatment of such sludge.

That is, organic sludge is generated from the processing of large amounts of food waste, food waste or related wastewater from dense dwellings in cities, sludge from food processing or paper mills, and livestock farms. Livestock manure.

These sludges are wastes containing a lot of water, and they usually contain about 80% water even if they are compressed to remove some of the water. As such organic sludge contains a lot of water, it is difficult to treat the sludge in a general incineration facility, but the incineration effect is extremely small and environmental pollution such as smoke or odor occurs. In addition, when the sludge is buried in the ground, groundwater may be contaminated by the leachate, the ground may be weakened, and it is difficult to secure the landfill itself. Sludge was dumped at sea, but dumping of sludge was legally prohibited by the London Convention on the Prevention of Marine Pollution.

Therefore, in order to solve this problem, the present invention studies a method of drying and using a humid organic sludge as a fuel, and techniques related to these drying apparatuses have been developed and patented.

"Multi-stage screw dryer" of Korean Patent Laid-Open Publication No. 10-2002-0005917 is composed of a screw up and down in the dryer housing to gradually transfer the sludge supplied from the inlet, and the moisture on the surface of the dried material is heated by convective heat and radiant heat, This is how it is evaporated. At this time, since the hot air supplied from the lower hot air inlet to dry the sludge loaded on the screw of the multi-stage, it is limited to the drying function by the hot air, and it takes a long time to dry the sludge containing 60% or less of water, and thermal efficiency There is a problem that the processing efficiency is low and the maintenance cost is high because it is not high. In addition, the Republic of Korea Patent Publication No. 10-2003-0079397 "Food Waste and Shaft Drying Device" is a method of using the convection heat drying method and the near-infrared lamp that generates a lot of convective heat by rotating the waste supplied into the gas It consists of a drying device that heats food waste. This device has the disadvantage of not being able to carry out a large amount of drying. The devices described in these patents have a problem of low throughput and high maintenance cost due to limited throughput of sludge since drying is performed in a state where sludge is stacked, and particularly in the case of applying a screw method, it is a technology focused on sludge transportation. There is a problem that the inner part of the sludge cannot be dried and the positions thereof cannot be changed and the problem of being limited to drying of the surface and the grinding action are almost unexpected.

Korean Patent No. 10-0539413 discloses a plurality of screws and sludge supplied to the screw which are rotated in parallel so that the pitch of the rotary blades are alternately arranged so that the sludge to be dried is transferred to the other end by the rotary blades of the screw. The surface of the sludge was crossed by stirring and mixing to increase the drying effect. Therefore, there is an advantage that a large amount of sludge can be processed, while the highly viscous sludge agglomerates with each other, causing a phenomenon in which the sludge is biased in one direction, and the sludge is crushed, stirred, and transported due to the sludge biased. There is a problem that some of the thermal efficiency is lowered properly.

This technology has a problem that the drying effect is not increased due to insufficient agitation and grinding function of sludge, the drying effect is deteriorated because the sludge cannot be replaced up and down or inside and outside, and the moist sludge with high moisture content and high cohesion between organisms In case of drying, there is a problem that the power means is overloaded due to the sticking phenomenon formed by the sludge agglomeration with each other, the problem of deterioration of the drying effect due to lack of air permeability, and the problem of elimination and discharge of odor caused by drying are not improved at all. will be.

Domestic Patent Publication No. 10-0539413

Technical problem of the present invention is to dry the sludge with high water content and strong cohesion between organisms such as food waste, sewage sludge, food residue, food processing by-products, livestock manure.

Another technical problem of the present invention is to prevent a large mechanical load from being strengthened by cohesion between sludges, and to improve drying efficiency by eliminating deficiency of breathability due to shrinkage of sludges in a drying process.

Another technical problem of the present invention is to apply a complex heating method using conduction heat as well as convection heat and radiant heat by mixing various kinds of metal materials having different sizes so that conduction heat can be transferred to the inside of the building.

According to one aspect of the invention, the sludge drying method using the conductive thermal energy

Incorporating at least one of aluminum (Al), iron (Fe), copper (Cu) in the sludge and mixing different metal pretreatment materials of different sizes, the step of introducing hot dry air into the sludge mixed with the metal pretreatment material Vibrating a dryer to collide the sludge with the metal pretreatment material to crush the sludge, injecting hot dry air into the collided sludge and the metal pretreatment material, and discharging the sludge and the metal pretreatment material. And separating the metal pretreatment material from the dried sludge.

The present invention can compensate for convection and radiation through the conductive heat of the metal material introduced into the sludge.

According to the present invention, it is possible to increase the warming effect of the to-be-dried product from the heat source of the upper part, shorten the drying time by sequential transfer, and increase the drying effect. Due to this, the drying effect can be increased.

1 is a flowchart showing an example of a sludge drying method according to the present invention.
2 is a view illustrating a process of drying the sludge according to the present invention.
3 illustrates an example of a vibration and a compressor for vibrating or compressing sludge with a metal pretreatment material according to an example of the present invention.
Figure 4 shows an example of a device that is supplied, agitated and vibrated pretreatment material according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In addition, in order to clearly disclose the present invention, parts not related to the present invention are omitted, and the same or similar reference numerals denote the same or similar elements in the drawings.

The objects and effects of the present invention may be naturally understood or more apparent from the following description, and the objects and effects of the present invention are not limited only by the following description.

The objects, features and advantages of the present invention will become more apparent from the following detailed description. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, the drying refers to a process of removing moisture from the dried body. Generally, to-be-dried bodies such as sludge are removed by steaming water using heating or reduced pressure. At this time, water vaporization usually occurs only on the surface of the to-be-dried body and is dried by the difference between the vapor pressure of the surface of the to-be-dried body and the vapor pressure of the air.

In the initial stage of drying, the moisture contained in the surface of the to-be-dried is first vaporized, the water in the to-be-dried is intact, and the rate of water removal is constant because the surface is evaporated, so that the drying rate is constant.

Then, when the surface of the to-be-drying body dries, the to-be-drying body, such as organic sludge, shrinks and is tacky, thus delaying the rate at which the internal moisture is transferred to the surface and gradually decreasing the surface moisture removal rate, which is referred to as rate reduction drying.

In summary, the higher the specific gravity drying rate in the drying process, the higher the drying effect. The larger the surface area of the dry matter, the closer to the rate drying.

If a metal material having a high thermal conductivity is mixed inside the to-be-contained body and thermal energy is rapidly conducted to the inside of the to-be-contained body, heat transfer to the inside of the to-be-contained body will be good and the heat will dry faster. . The present invention provides a drying method and apparatus which achieves high drying efficiency based on this idea. In addition, during drying, the drying shrinkage of the drying body creates voids between the metal material and the drying body, and the voids extend to the inside of the drying body, thereby increasing the surface area of the dry body, so that convective heat energy and radiant thermal energy are also supplied between the pores. The drying efficiency is higher. For reference, the thermal conductivity of the materials is equal to dry air 0.02, plastic 0.16, wood (organic) 0.17, glass 0.81, brick 1.00, concrete 1.40, iron 80, aluminum 237, gold 317, copper 401, silver 429 (where the unit is J / msK, J = calorie, m = meter, s = time, K = temperature)

On the other hand, organic or inorganic base metals, which are the main components of the sludge to be dried, have a thermal conductivity of 0 to 2 J / m.s.K, so that thermal energy is not transferred to the inside of the drying body, and thus drying inside the drying body is difficult and the drying efficiency is low. On the other hand, ferrous or non-ferrous metals have a thermal conductivity of 80 to 400 J / m.s.K, so they can conduct 40 to 200 times more thermal energy than organic or inorganic nonmetals, which will increase the drying effect.

Now, a sludge drying method for treating various kinds of sludge generated in a large amount in food waste, livestock manure, and industrial production according to the present invention will be described.

1 is a flowchart showing an example of a sludge drying method according to the present invention.

Referring to FIG. 1, a metal material having various sizes is mixed in a sludge (S110). The metal material is made of aluminum (Al), iron (Fe), copper (Cu), and the like, in particular, thermal conductivity. It is preferable that this material is 80 J / msK or more. In summary, the metal pretreatment material may be a metal piece, a metal wire, a metal coil, or a metal bead, and the above metal pieces, metal wires, metal coils, and metal plates may be appropriately combined. The metal pretreatment material is not limited to the above example and can be modified as many as those skilled in the art. In addition, the present specification describes a metal pretreatment material consisting of the metal beads to help a clear understanding of the invention as an example.

Subsequently, dry and high temperature air is introduced into the sludge mixed with the metal (S120). At this time, dry, high temperature air evaporates moisture from the sludge surface due to convection, and moisture inside the sludge moves to the sludge surface due to capillary action. It rapidly increases conduction heat energy to the inside of the sludge due to the conduction of the metal, and the pores are formed by the drying and shrinkage of the sludge due to the transfer of heat energy to the sludge and the metal contact area, and the dry and high temperature is maintained between the pores where the sludge surface area becomes wider. Air is distributed.

Subsequently, the sludge is crushed by causing the sludge to collide with the metal material by the vibration of the dryer (S130). Due to the vibration, the crushing size of the sludge is broken by various kinds of metal materials. Finely crushed sludge is subjected to continuous heat transfer, which is dried and crushed more continuously.

At this time, the dried sludge and discharge the metal material of various types (S140). Separation of various types of metal materials from the dried sludge (S150)

In addition, the separated metal material may be mixed in the sludge again and continuously dried (S160).

2 is a view illustrating a process of drying the sludge according to the present invention. For example, it will be described that drying takes place in the first drying furnace and the separated metal material is recycled in another drying furnace (second drying furnace).

Referring to FIG. 2, incorporation 210 of metal pretreatment materials having different sizes (eg, aluminum, iron, and copper) is uniformly mixed in a sludge containing a large amount of water (210). In the pretreatment of the metal pretreatment material, the sludge and the pretreatment material are mixed or agitated to mix metal materials having different sizes and volumes. 3 shows an example of a vibration and a compressor for vibrating or compressing sludge with a metal pretreatment material according to an example of the present invention. Referring to FIG. 3, after the metal pretreatment material and the sludge are mixed or mixed, the metal pretreatment material is moved as the vibration and the compressor vibrate clockwise, counterclockwise or various other directions at predetermined cycles to move or circulate the contents. And sludge are stirred and compressed. In this case, the stirrer may further include a separate propeller to stir the sludge.

At this time, the hot dry air evaporates the moisture of the sludge surface due to the convection phenomenon (212). That is, drying by convective heat is performed in a 1st drying furnace.

As the sludge surface dries, moisture inside the sludge moves to the sludge surface (214).

At the same time, the heat of the metal pretreatment material is transferred 216 to the interior of the sludge, ie drying by conduction heat in the first drying furnace is performed. Metal materials with different sizes and volumes, which are metal pretreatment materials, are introduced into the sludge and heat energy is conducted to the inside of the sludge and dried.

Repeated drying and shrinkage inside the sludge creates voids (218)

Hot dry air flows between these pores (220)

For example, the sludge and the metal material may be collided by vibrating the drying apparatus of the first drying furnace (230). When the drying apparatus is vibrated, the sludge is secondary mixed with metal materials having different sizes and volumes, which are metal pretreatment materials. When the sludge is dried, it becomes sticky at first, and then aggregates. When the water content of the sludge becomes 30% or less, the sludge disappears and dries as it is. As an example, FIG. 4 shows an example of an apparatus in which a pretreatment material is supplied, stirred, and vibrated according to an example of the present invention. Referring to FIG. 4, when the drying apparatus vibrates while the sludge has no adhesiveness and is agglomerated, the metal material remains intact and the sludge is finely pulverized due to the difference in strength due to the collision between the dried sludge and the metal pretreatment material (232). The finely crushed sludge is broken into smaller pieces when dried by hot dry air (234).

At this time, when the drying apparatus of FIG. 4 vibrates, among the finely broken sludge and the metal materials having different sizes and volumes, the metal material and sludge having a smaller size and volume and a relatively high specific gravity sink down (410), size and volume. The large metallic material is gathered upward by the small and bulky metallic material, and the large sludge is gathered upward 420. For example, a magnetic separator 430 may be provided on the sludge to separate and discharge the metal material, thereby separating the metal pretreatment material first.

The mixture of dried sludge and metal material thus collected in the first drying furnace is discharged (236), and metal materials having different sizes and volumes are separated from the dried sludge (238).

The separated metal material is added to the second drying furnace and mixed in the sludge to be dried (240). Metal materials of different sizes and volumes can be collected separately and mixed in undried sludge and subsequently dried.

In another example according to the present invention, the sludge drying apparatus includes: a mixing unit including at least one of aluminum (Al), iron (Fe), and copper (Cu) in a sludge and mixing a plurality of metal pretreatment materials having different sizes; An input unit for inputting hot dry air into the sludge mixed with the metal pretreatment material; A collision part vibrating a dryer to collide the sludge with the metal pretreatment material; A second input unit for inputting hot dry air into the sludge and the metal pretreatment material that collide; A discharge part for discharging the sludge and the metal pretreatment material; And a separating part separating the metal pretreatment material from the dried sludge by using magnetic and specific gravity. At this time, the input unit and the second input unit may be the same input unit.

Although the sludge rapid drying method by the apparatus according to the preferred embodiment of the present invention as described above has been shown in accordance with the above description and drawings, this is merely an example and within the scope not departing from the technical spirit of the present invention. It will be appreciated by those skilled in the art that various changes and modifications are possible.

Claims (6)

In the sludge drying method using the conductive heat energy,
Incorporating a plurality of metal pretreatment materials composed of at least one of aluminum (Al), iron (Fe), and copper (Cu) into the sludge and having different sizes from each other;
Injecting hot dry air into the sludge mixed with the metal pretreatment material;
Vibrating a dryer to collide the sludge with the metal pretreatment material;
Injecting hot dry air into the impacted sludge and the metal pretreatment material;
Discharging the sludge and the metal pretreatment material; And
Separating the metal pretreatment material from the dried sludge by using magnetic and specific gravity. The method of claim 1,
Drying and shrinking the sludge in the interior of the sludge, and causing hot air to flow between the pores;
Vibrating a drying apparatus to collide the sludge with the metal material to secondly mix the sludge with the metal treatment material;
Moisture of the sludge is less than 30% and dried in a state where the adhesiveness disappeared and finely pulverizing the sludge using a stirring and vibration device; And
And adding hot dry air to the finely crushed sludge. The method of claim 2,
Among the finely divided sludge and the metal materials having different sizes and volumes, the metal material having a smaller size and volume and a relatively high specific gravity and dry crushed sludge are separated from the bottom, and the size and bulky metal materials are The method of claim 1, further comprising the steps of collecting the large sludge from above and collecting the large sludge from the upper side by separating the metallic material with magnetic and specific gravity separators. The method of claim 3, wherein
Sludge drying method characterized in that the separated metal pretreatment material is mixed into the sludge again and continuously dried. The method of claim 1,
The metal pretreatment material is a sludge drying method, characterized in that the thermal conductivity is more than 80 J / msK. A mixing unit including at least one of aluminum (Al), iron (Fe), and copper (Cu) in the sludge and mixing a plurality of metal pretreatment materials having different sizes;
An input unit for inputting hot dry air into the sludge mixed with the metal pretreatment material;
A collision part vibrating a dryer to collide the sludge with the metal pretreatment material;
A second input unit for inputting hot dry air to the sludge and the metal pretreatment material that collide;
A discharge part for discharging the sludge and the metal pretreatment material; And
And a separator for separating the metal pretreatment material from the dried sludge by using magnetic and specific gravity.