KR101469166B1 - Food trash drying method - Google Patents

Abstract

The present invention relates to a food waste drying method capable of drying food waste using waste heat. The food waste drying method comprises: a first step of generating combustion gas by primary combustion of waste fuels in a combustor (100); a second step of putting the combustion gas into the front end part of a mixing chamber, performing secondary combustion of the combustion gas at 850 to 980°C to stabilize the combustion gas and supplying food wastewater and cooling air to the rear end part of the mixing chamber to adjust the temperature between 350 and 400°C; a third step of drying the food waste supplied into a food dryer (300) by putting the combustion gas (300) into the food dryer (300); a fourth step of discharging the completely dried food waste out of the food dyer (300); and a fifth step of purifying air existing inside the food dryer (300) in the process of drying the food waste. Therefore, the present invention can prevent the waste of resources by enabling food waste to be dried completely via waste heat using waste plastic solid fuels to recycle resources, and can protect the natural environment by disposing of food waste after drying the food waste completely to prevent malodors or the contamination of soil induced by the food waste.

Description

{FOOD TRASH DRYING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drying food waste, and more particularly, to a method for drying food waste using a waste plastic solid fuel to completely dry and treat the food waste to protect the natural environment.

As households become increasingly urbanized and grouped, the treatment of residues (food waste) emitted by households and businesses is becoming one of the biggest problems to be solved by local governments. In the case of waste such as residues, Causing serious environmental pollution problems.

In the case of food waste, the processing site is limited and the amount of treatment is also limited. Therefore, an efficient treatment method for vast amounts of food waste discharged every day is urgently required.

There have been many discussions on how to manufacture compost or alternative fuels using food waste in accordance with such a demand, but such measures have been widely discussed such as air pollution during manufacturing process and side effects It is difficult to realize the current situation because the issues are not resolved.

In addition to such food wastes, wastes such as sewage sludge and various kinds of functional sludge generated in a sewage end treatment plant and the like are very troublesome, and conventionally, sludge has been treated using a method such as ocean dumping or incineration .

However, since the sludge contains a large amount of water (80% in average moisture content), its volume is large, it incurs a considerable cost for incineration, and a problem of treating a large amount of leachate prior to incineration of the sludge It is not possible to efficiently treat leachate. However, if the sludge is incinerated without removing the leachate, it consumes a lot of fuel for incineration, and a large amount of dioxins, which are fatal to the environment in the incineration process, I can not help it.

In addition, the marine dumping of sludge will be prohibited systematically due to the environmental pollution problem, so it may be considered to dispose of the sludge in disposal, but when the sludge is directly buried, the volume of the sludge becomes a problem, It is necessary to appropriately and efficiently treat not only food wastes but also sludge.

It is an object of the present invention, which has been devised in view of the above, to provide a method of completely drying food wastes by waste heat using waste plastic solid fuel to prevent waste of resources and completely dry food wastes And a method for drying food garbage that can protect the natural environment by preventing odor or soil pollution caused by food garbage by disposal.

To achieve the above object, the present invention provides a method of drying food waste, comprising: a first step of combusting waste fuel in a combustor 100 to generate combustion gas;

The combustion gas is injected into the front end of the mixing chamber to be stabilized by secondary combustion at 850 ° C to 980 ° C, and then the waste water and cooling air are supplied at the rear end of the mixing chamber to adjust the temperature to 350 to 400 ° C A second step;

A third step of putting the combustion gas into the food drier 300 and drying the food waste supplied into the food drier 300;

A fourth step of discharging the dried food waste to the outside of the food drier 300;

And a fifth step of purifying the air existing in the food drier 300 in the course of drying the food waste.

In the third step, the food waste introduced into the center of the food drier is conveyed in a zigzag form upward and downward along the height direction of the food drier, thereby drying the food waste.

In the fifth step, the air is introduced into the cyclone to remove the debris contained in the air, and the air removed from the debris is introduced into the filter, thereby removing particles contained in the air And removing the deodorized air by injecting the air from which the particles have been removed into the deodorizing absorber.

In addition, the air having been removed from the particles may be introduced into the deodorizing absorption tower after the drying reaction process is performed before the deodorization absorption tower is charged.

In addition, in the drying reaction step, the drying reaction may proceed inside the drying reactor by introducing the air with the particles removed into the drying reactor together with the activated carbon and the slaked lime.

After the progress of the fifth step is completed, the air may be supplied to the stack by a separate discharge fan and then discharged to the outside.

In addition, it is preferable that the cooling air includes odor supplied from a duct connected to the food processing plant.

In addition, the water content of the sludge after drying in the food drier is preferably 30% or less.

In addition, it is preferable that the waste fuel supplied to the combustor is a waste plastic solid fuel (RPF).

According to another aspect of the present invention, there is provided a system for drying food waste,

A combustor (100) for primary combustion of waste fuel;

A front end for secondary combustion of the combustion gas generated in the combustor at 850 ° C to 980 ° C, and a combustion gas, negative wastewater, and contaminated cooling air passing through the front end to control the temperature of the combustion gas to 350 to 400 ° C A mixing chamber (200) including a rear end portion where the negative wastewater is evaporated and the odor of the cooling air is removed; And

And a food drier (300) in which food waste is introduced and the food waste is dried by the combustion gas.

At this time, it is preferable that an outer wall of the mixing chamber is provided with a heat exchanger which is supplied with process water and generates heat by heat exchange with the heat radiated to the outside.

As described above, the method for drying food garbage according to the present invention has the effect of preventing waste of resources by recycling resources by completely drying food waste with waste heat using waste plastic solid fuel.

In addition, there is an effect that the natural environment can be protected by preventing the smell or the contamination of the soil caused by the food waste by drying the food waste to compost and feed.

FIG. 1 is a flowchart sequentially illustrating a method of drying food garbage according to an embodiment of the present invention,
2 is a schematic view schematically showing the structure of a food waste drying system for performing a method of drying food waste according to an embodiment of the present invention.

Hereinafter, a method of drying food waste according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a flowchart sequentially illustrating a method of drying food waste according to an embodiment of the present invention. FIG. 2 is a schematic view illustrating a structure of a system for drying food waste, which performs a method of drying food waste according to an embodiment of the present invention. Fig.

First, the structure of the food waste drying system using the method of drying food waste according to an embodiment of the present invention will be described as follows.

2, the food waste drying system according to the present invention includes a combustor 100 in which a waste plastic solid fuel (RPF: Refused Plastic Fuel) is injected by a conveyor to dry food waste, A mixing chamber 200 connected to the combustion chamber and including a front end for performing secondary combustion and a rear end for supplying and mixing the wastewater and the cooling air and a mixing chamber 200 connected to the mixing chamber 200 through the communication pipe 110, A food drier 300 for introducing the combustion gas heated by the burner 100 into the inside and drying the introduced food wastes, a purifier 300 for purifying the air existing in the inside of the food drier 300 in the course of drying the food wastes, And a processing unit.

The combustor 100 serves to generate a combustion gas and transfer it to the front end of the mixing chamber 200. To this end, one side of the combustor 100 is provided with a separate It is connected to conveyor. The internal temperature of the combustor is burned at a high temperature of 1000 ° C or higher, and the outlet temperature of the combustor is maintained at 850 ° C to 980 ° C.

At the front end of the mixing chamber 200, the secondary combustion of the combustion gas flowing after combustion in the combustor proceeds, and at the rear end, the combustion gas in which the secondary combustion proceeds, the mixed wastewater and the cooling air are mixed, And then flows into the food drier 300 in a lowered temperature state.

The gas generated after the primary combustion in the combustor 100 by the secondary combustion proceeding at the front end of the mixing chamber 200 stays in the mixing chamber 200 for a certain period of time and a substance such as CO contained in the gas The gas can be stabilized by further burning.

At the rear end of the mixing chamber 200, the cooling air and the liquor wastewater, which is liquid generated from the food, are introduced. The cooling air and the negative wastewater lower the temperature of the combustion gas to below 400 ° C.

The cooling air serves to regulate the temperature of the high-temperature dry combustion gas injected into the food drier (300). That is, by mixing the cooling air and the combustion gas generated in the mixing chamber 200 at an appropriate ratio, the temperature of the combustion gas is controlled to 400 ° C or less.

At this time, the cooling air introduced into the mixing chamber 200 can use contaminated air connected from the duct of the food waste treatment plant. That is, the odor of the contaminated air is injected into the chamber 200, and the odor of the food waste can be removed efficiently at a high temperature.

The negative wastewater means contaminated liquid wastewater generated from food wastes. The negative wastewater generated in the food wastewater treatment plant is supplied to the rear end of the mixing chamber to lower the temperature. In addition, It is possible to effectively treat the waste water.

It is effective that the cooling gas and the negative wastewater are injected in a spraying manner so that the evaporation can be rapidly performed by widening the contact area with the hot combustion gas.

On the other hand, a heat exchanger is installed on the outer wall of the mixing chamber, and the process water is introduced into the mixing chamber 200 to be heat-exchanged with heat generated from the outer wall of the mixing chamber 200, thereby being used as steam. These process numbers may or may not be used as needed.

The food drier 300 serves to dry the food waste introduced into the inside of the mixing chamber 200. To this end, one side of the food drier 300 is connected to the inside of the combustion chamber 300, And one end communicates with the communicating tube 110 connected to the rear end of the mixing chamber 200.

The communicating tube 110 communicates with a central region of one side of the food drier 300. In the inside of the food drier 300, food waste put into the dryer 300 flows upward and downward along the height direction of the food drier 300 in a zigzag shape It is preferable that a plurality of conveyors are stacked so that sufficient drying can be performed by increasing the time during which the food waste is retained in the food drier 300. [

A part of the food garbage is dried while moving in a zigzag direction on the basis of the central area of the food dryer 300 by the plurality of conveyors, and the remaining food garbage is dried by the center of the food dryer 300 And moves in the zigzag direction to the lower side so as to be dried.

The purifier may purify contaminants contained in the air generated by drying the food waste in the food drier 300. To this end, the purifier may include a cyclone 400 for removing the debris contained in the air, A dust collector 500 for removing particles (dust) contained in the air from which debris is removed, and an odor elimination absorption tower 600 for removing the odor of air from which particles have been removed.

The cyclone 400 is a member formed in an inverted conical shape. When the air is introduced from the upper side of the cyclone 400, the cyclone 400 has a relatively smaller diameter than the upper side of the cyclone 400 due to the centrifugal force 400 so that the debris contained in the air is collected and discharged to the outside.

The dust collector 500 is configured such that air having a relatively large size residue removed from the cyclone 400 is injected to collect particles (dust) having a relatively smaller size than the residue contained in the air, It also removes small contaminants contained in the air.

The air that has been completely removed from the air while passing through the cyclone 400 and the dust collector 500 is introduced into the deodorizing absorber 600 to completely remove the bad odor contained in the air, The air is finally discharged to the outside after moving to the stack 800.

A drying reactor 700 is provided between the cyclone 400 and the dust collector 500. The drying reactor 700 is operated to remove the dioxins and acidic gases generated by drying the food waste in the food drier 300, , Smell, etc., and reacts with activated carbon and calcium hydroxide to neutralize.

To this end, one side of the drying reactor 700 is connected to a conveyor supplied with activated carbon and slaked lime from an activated carbon supplier 710 and a slaked lime feeder 720, respectively, so that activated carbon and lime are supplied to the inside thereof.

Activated carbon is strongly adsorbed and most of the constituent material is carbonaceous material. It is used to absorb gas or moisture with adsorbent, or used as a decolorizer, and treated with chemicals such as zinc chloride to dry wood and lignite.

The activated carbon has a large surface area, a perfect processing structure, excellent adsorption power, high physical and mechanical strength, strong durability by long-term use, and does not cause secondary pollution.

Hydrated lime is a hydroxide formed by the reaction of quicklime with water. It has a low solubility in water. The strength of alkali is intermediate between calcium oxide and quicklime. When it is left in the air, it absorbs carbon dioxide and turns into calcium carbonate to remove carbon dioxide Is used.

The activated carbon and the slaked lime are introduced into the drying reactor 700 together with the air to react to remove dioxin, acidic gas, odor and carbon dioxide contained in the air.

The temperature suitable for each process step shown in FIG. 1 is as follows. The temperature is preferably 850 to 980 캜 in G1, 350 캜 to 400 캜 in G2, 110 캜 to 150 캜 in G3, 110 캜 to 120 캜 in G4 and 90 캜 to 120 캜 in G5 to G8.

G1 is a temperature of the outlet of the combustor, preferably 850 to 980 DEG C. If the temperature is less than 850 DEG C, secondary combustion in the mixing chamber is not performed well. If the temperature exceeds 980 DEG C, There is a possibility that However, the internal temperature of the combustor may be 1000 ° C or higher.

And G2 is a temperature between the mixing chamber and the food drier of from 350 to 400 deg. The temperature of the air is adjusted by mixing the cooling air with the high-temperature and dry combustion gas generated in the mixing chamber 200 at an appropriate ratio. The temperature of the air introduced into the food drier 300 is in the range of 350 ° C. to 400 ° C. Within the above range.

If the temperature of the air is lower than 350 ° C, the food waste is not dried quickly. If the temperature of the air exceeds 400 ° C, carbonization of the food waste occurs.

G3 and G4 are the temperature at the front and rear of the cyclone, G5 and G6 are the temperature at the front and rear of the dust collector, G7 is the temperature after the deodorizing absorber, and G8 is the discharge temperature of the stack. After G3, the temperature of the air is gradually lowered without supplying a separate heat source as the process progresses, and the process is completed by flowing into the final stage 800 of the food drying system.

Example

FIG. 3 is a table summarizing data of temperature and pressure for each process by operating the food waste drying system according to the present invention. FIG.

stream number G1 G2 G3 G4 G5 G6 G7 G8 유율 Nm3 / hr.wet 11,534 32,812 37,210 37,210 37,372 37,372 37,372 37,372 온도 ℃ 972 350 120 115 110 105 105 105 pressure mmAq -20 -40 -140 -240 -290 -490 -590 50

The method for drying food waste using the system for drying food waste according to the present invention having such a configuration will now be described.

First, the waste plastic solid fuel is introduced to the combustor 100 by a separate conveyor, and the foreign substance generated by burning the waste plastic solid fuel is discharged to the outside by a separate foreign matter discharge conveyor connected to the combustor 100.

The combustion gas generated while the waste plastic solid fuel is firstly combusted in the combustor 100 has an outlet temperature of 850 ° C. to 980 ° C. The combustion gas is injected into the front end of the mixing chamber 200 to be secondarily combusted, The temperature of the hot and dry air mixed with the cooling air and the negative wastewater and introduced into the food drier 300 forms a temperature of 350 to 400 ° C.

At this time, the air having been firstly combusted in the combustor 100 stays at the front end of the mixing chamber 200, and the secondary combustion is performed, thereby stabilizing the gas such as CO contained in the air.

In addition, negative wastewater and cooling air are injected into the rear end of the mixing chamber 200, and the wastewater is evaporated and the odor of the cooling air is removed. Also, after the temperature inside the mixing chamber 200 is controlled by the cooling air, the combustion gas is supplied to the food drier 300 side in the mixing chamber 200 and is contacted with the food (dehydrated cake) sludge coming into the dryer inlet, do.

In the mixing chamber 200, the heat source is introduced into the food drier 300 through the communicating pipe 110. In the food drier 300, the heat source is introduced into the food drier 300 by a separate conveyor moving in a zigzag shape So that the food garbage is allowed to stay in the food drier 300 for a longer time to complete drying of the food garbage.

The food waste that has been dried by the above-described process is sludge having a water content of 30% or less and is discharged to a separate discharge conveyor. The air generated as the food waste is dried is introduced into the cyclone 400.

The air introduced into the cyclone 400 is removed by the cyclone 400 from the relatively large residue contained in the air, and the air from which the residue is removed is further introduced into the dust collector 500.

The air passing through the cyclone 400 is introduced into the drying reactor together with activated carbon and slaked lime supplied from the activated carbon supplier and the slaked lime feeder, respectively, before the air is introduced into the dust collector 500. [ And reacts with activated carbon and slaked lime to remove moisture, odor and carbon dioxide contained in the air.

Thereafter, the gas introduced into the dust collector is adsorbed to and removed from the filter by the reaction of the activated carbon and the slaked lime, and particles (dust) having a relatively small volume are removed as compared with the residue.

The air having been removed from the particles is supplied to the deodorizing absorber 500 for removing the odor in the second stage to remove the odor contained in the air and then supplied to the stack 800 by a separate discharge fan 810 So that the drying process of the food waste is completed.

Since the food is dried by the above-mentioned process, it is possible to prevent the waste of resources by recycling the resources and to completely dry and dispose of the garbage so that no wastewater is generated at all. Thus, odor or contamination caused by food waste It is possible to protect the natural environment.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It is to be understood that both the technical idea and the technical spirit of the invention are included in the scope of the present invention.

100: mixing chamber 110: communicating tube
200: Combustor 300: Food Dryer
400: Cyclone 500: Dust collector
600: Deodorizing absorption tower 700: Drying reaction furnace
710: Activated carbon feeder 720: Slurry feeder
800: Stack 810: Discharge fan

Claims (11)

A first step of combusting the waste fuel in the combustor (100) to generate a combustion gas;
The combustion gas is injected into the front end of the mixing chamber 200 to be stabilized by secondary combustion at 850 to 980 ° C. and the odor supplied from the duct connected to the waste water and the food processing plant is supplied to the rear end of the mixing chamber 200 A second step of controlling the temperature of the combustion gas to 350 to 400 DEG C by supplying cooling air containing the cooling air;
The flue gas is introduced into the food drier 300 so that the food waste introduced into the center of the food drier 300 is conveyed in a zigzag form upward and downward along the height direction of the food drier 300, Step 3;
A fourth step of discharging the dried food waste to the outside of the food drier 300;
Removing the debris contained in the combustion gas by injecting the combustion gas into the cyclone 400 and injecting the combustion gas from which the debris has been removed into the filter 500 to remove the particles contained in the combustion gas A step of injecting the combustion gas from which the particles have been removed into the drying reactor 700 together with the activated carbon and the slaked lime to neutralize the combustion gas and the neutralized combustion gas into the deodorization absorption tower 600 to remove the odor A fifth step of purifying the flue gas present in the food drier (300), including the step And
And the purified combustion gas is supplied to the stack (800) by a separate discharge fan (810) and then discharged to the outside. delete delete delete delete delete delete The method according to claim 1,
Wherein the water sludge after drying in the food drier has a water content of 30% or less. 9. The method of claim 8,
Wherein the waste fuel supplied to the combustor is a waste plastic solid fuel (RPF). A combustor (100) for primary combustion of waste fuel;
The front end of the combustion gas generated in the combustor is secondarily combusted at 850 to 980 ° C, and the combustion gas, the wastewater and the contaminated cooling air passing through the front end are supplied to adjust the temperature of the combustion gas to 350 to 400 ° C A mixing chamber 200 including the rear end portion where the negative wastewater is evaporated and the odor of the cooling air is removed; And
And a food drier (300) including a food processor (300) including a food purifier, a food purifier (300) for purifying contaminants contained in the air generated by drying the food purifier ,
And a heat exchanger provided in the outer wall of the mixing chamber 200 for generating steam by heat exchange with heat radiated to the outside by supplying process water,
And a duct for supplying contaminated cooling air from a food waste treatment plant connected to a rear end of the mixing chamber 200,
The purifier of the food drier 300 includes a cyclone 400 for removing debris contained in the air, a dust collector 500 for removing particles contained in the debris-removed air, an activated carbon feeder 710, A drying reactor 700 connected to the slak lime feeder 720 to neutralize the air from which the particles have been removed and an odor removal absorber 600 for removing the odor of the neutralized air. system.

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