KR20100091513A - Treatment apparatus for food waste by microwave heating - Google Patents

Abstract

PURPOSE: A food garbage treatment apparatus using microwave heating is provided to maximize drying efficiency by adjusting the input of energy according drying sections. CONSTITUTION: A food garbage treatment apparatus using microwave heating comprises an oscillator, a waveguide(40), a drying case(50), and a drying chamber(10). The oscillator generates microwaves. The waveguide smoothly supplies microwave to the drying chamber. The drying case receives the amount of the food waste. The microwave can easily penetrate through the drying case. The drying chamber induces the resonance of the microwave irradiated from the waveguide. A door is installed in the drying chamber for the incoming and outgoing of the load.

Description

Food waste disposal system using microwave heating {TREATMENT APPARATUS FOR FOOD WASTE BY MICROWAVE HEATING}

The present invention relates to a food waste treatment apparatus containing a large amount of water, and more particularly, to a treatment apparatus for efficiently drying food waste by using microwave heating.

Food wastes are classified as food wastes, which are generated during the preliminary stages of food processing and those left after being eaten and processed. These food wastes contain a large amount of water with a water content of 50 to 95%. If you want to recycle, the loss of moisture is very important. Weight loss treatment of food waste is called a drying treatment method. In general, drying means gasifying liquid moisture to separate it from the material. In this process, the important thing is the input of drying energy. Even in the technical field of the food waste drying treatment apparatus, heat sources for drying are classified into hot air, warm air, and conductive heating pulverization. The present invention is in the technical field using microwave heating as a heat source for drying food waste.

In general, food wastes emitted from homes or restaurants contain a large amount of water, and food wastes are mainly composed of cereals, vegetables, fruits, meats, and fish. An important element of the composition of the substance, at least about 50% of the moisture of the substance is in the form of bound water. In addition, carbonization phenomenon occurs at a temperature of more than 140 ℃ because of the organic structure of the food material. Of course, in the drying of food waste, the generation of carbonization after drying may not be regarded as an important harmful phenomenon. However, odor generation during carbonization during drying affects the pleasant environment and thus is considered as an important design factor of the drying device configuration. For this reason, it is not possible to apply a high temperature heat source for drying food waste, which takes a very long time to dry. The selection of a suitable heat source has been considered an important technique for the efficient drying of food waste.

Food waste is sometimes emitted as a single food, but in most cases it consists of a mixture of foods. These mixed states are different in water content of each material and have a very different form of water present in each material. The choice of heat source and the application process are very important for the constant drying of these mixed materials to the target moisture content.

Food waste has a common odor due to the inherent odor of the food state and corruption caused by delay in storage. In the drying of such a substance, the outflow of odor due to the behavior of odor particles generated in the drying process is expected. In order to solve the environmental hazards caused by the release of odors, the treatment technology of dry exhaust humid air should be carefully considered in food waste drying treatment.

In general, the term "drying" refers to vaporizing and removing moisture of a liquid contained in a material, and latent heat of evaporation is essential. It is inevitable that energy costs are incurred for drying. The ultimate technology of any drying machine results in improved drying efficiency.

Based on the review of the basic technology related to food waste drying treatment, a significant problem is inherent in various sectors. The heat source of the conventional food waste drying apparatus adopts hot air, hot air, and some conductive heat transfer methods, and the treatment of the dry wet air is mainly exhausted, and some use the synergistic effect of the heat transfer area during drying by using a stirrer or a pulverizer. Thus, the drying time is shortened and the efficiency is increased. The food waste drying apparatus to which the conventional technology is applied exhibits the following problems due to the characteristics resulting from the heat transfer mechanism of the indirect heating method.

Firstly, food waste is a substance containing a large amount of water (at least 55% or more), and about 50% or more of its moisture composition has a binding water structure, so that the limit function ratio that distinguishes ease of drying process is relatively high. For reference, the maximum moisture content is about 60% for radish and watermelon with high moisture content, and about 35% for rice. Food waste is a macromolecular organic material that contains a large amount of water. When moisture is less, the thermal conductivity is relatively low. Therefore, the drying time is delayed when heat is transferred from the outer surface of the material to heat through the heat conduction. And because the heat loss to the outside is large, the drying efficiency is very low. Of course, in the case of using a stirrer or a pulverizer, it is expected that the drying time and the efficiency are improved by increasing the heat transfer area during the stirring or grinding process, but the heat loss is increased due to the characteristics of the material used in the stirrer or the pulverizer. have. In the case of currently used food waste dryers, the drying efficiency is very low at 10-27%.

Secondly, since the flow method of the drying air mainly takes the exhaust method, it is very disadvantageous for the odor treatment generated during drying. Currently, the commonly used method is to apply a filter to solve this problem, and the filter is mainly composed of activated carbon particles, which is a life-long component that causes replacement costs during the use of the drying equipment and activated carbon waste after replacement. As a result, the generation of malignant waste rather than food waste causes other social and environmental problems. In order to improve this, Patent Publication No. 10-0706919 discloses a method of decomposing and discharging odor particles by burning exhaust gas generated during drying at a high temperature, but due to excessive energy input of a high temperature odor processor, the overall efficiency is low, resulting in a low consumer efficiency. There is a problem that the cost burden is increased.

The above is to identify the problems of the conventional food waste drying technology using hot air or conduction, which is an indirect heating method of the drying heat source, and to improve the problem, a drying apparatus using microwave heating, which is a heat source that can be directly heated to a dry object, is used. Several techniques have been invented, but this also poses a very serious problem in the practical use of drying of food waste.

For example, U.S. Patent No. 5,174,042 has been invented to some extent related to the vessel for microwave heating and the path of water and gas discharge during heating, but the odor removal of exhaust gas is caused by excessive input of energy by using a high temperature decomposition method using a heater. It is expected to lead to lower overall drying efficiency.

In general, microwave heating refers to a phenomenon in which microwaves are absorbed by a material from a material having a high dielectric constant and a dielectric loss meter to generate heat by itself. When the dry matter is present in the microwave environment, the temperature of the material is increased by the absorbed microwaves, and the moisture present in the water is separated from the dry water in the form of vapor when the latent heat of vaporization is obtained. At this time, if microwave energy is supplied above the latent heat of evaporation of moisture, evaporation of moisture takes place, and the remaining energy induces the temperature rise of the dry body, and if the temperature rises excessively, the dry matter is carbonized during drying. It can also cause. In other words, when drying using microwave heating, it is important to supply microwave energy corresponding to the evaporation rate of moisture. It is also very important to stop the supply of microwave energy when the target function rate is reached.

In this aspect, the US Patent No. 5,174,042 and the Korean Patent Publication No. 10-2006-0111104 are controlled by a temperature sensor installed in and outside the microwave drying chamber, but this is the temperature of the steam generated during drying and the sensible heat of the dry body. Detects the temperature caused by radiation and convection in accordance with the increase, which is very inaccurate to detect the temperature rise of the actual to-be-dried body, which causes a malfunction of the drying apparatus, and causes a harmful defect. Microwave energy control suggests the periodic control of ON-OFF, which causes the delay of drying time and the supply of maximum microwave energy in the ON state to suppress the carbonization phenomenon at the end of the period of low moisture drying in the subject. Below, the problem which is inadequate is shown.

Korean Patent Laid-Open Publication No. 10-0244389 proposes a drying chamber configuration using a kind of paddle-shaped stirrer in the construction of a food waste drying apparatus using microwave heating, but considering the drying treatment of dry steam and the characteristics of drying of food waste. As there is no specific technology on the microwave energy operation plan, it is considered to have no practical meaning.

In general, a technique using microwave heating as a drying heat source that induces direct heating of a material in the drying of a material having a solid state or a volume of a mixed state of a gel and a sol may increase drying efficiency and drying. This technique is very well known in terms of expecting a shortening time. What is important in drying using microwave heating is the structure of the microwave operation according to the drying characteristics of the dry matter, in particular, the drying characteristics of the food waste to be handled in the present invention, and the structure of the accessory device that can cope with it, and the odor during drying. It is a technique for practical use to constitute an environmental response element of the generated exhaust gas.

Accordingly, an object of the present invention is to use a microwave heating as the main heat source in the drying treatment of food waste composed of various kinds of foods, and in order to efficiently configure a gas flow atmosphere suitable for a drying environment using microwave heating It is to provide a food waste treatment apparatus to dry the composite.

Food waste has a difference in moisture content before drying due to its constituent properties, and it is important to achieve uniformity of the dry state after drying as a material having a difference in drying characteristics according to the organizational binding properties of the constituent materials. That is, after drying at the complex moisture content before drying, drying each of the constituent materials below the target moisture content is the first core of the technology of the present invention. The statistical value of the equilibrium moisture content due to climate during the year in Korea is 10-15%, the target moisture content in the present invention is set to 9% or less in consideration of the recycling concept after drying treatment of food waste.

Food waste has its own inherent odor and odor due to corruption in storage. Such liquid malodorous particles are evaporated by the temperature rise during drying, and when exposed to the external environment, an environmental discomfort is created, and thus a treatment technique thereof is required during drying. Accordingly, another object of the present invention is to provide a food waste treatment apparatus for condensing and liquefying exhaust gas generated during drying, and in this process, malodorous particles are collected in the condensate to suppress its behavior to discharge the condensate to the drain.

In general, when a substance is to be dried, the progress stage is divided into a material preheating section, a constant drying section, and a reduction rate drying section. Changes in drying speed, temperature rise of the material, etc. in this progress step are referred to as drying properties of the material. The main characteristic of this drying progress step is that as the drying proceeds, especially after the limit function period, the moisture remaining in the material decreases, and the drying speed is slowed, so that the energy participating in the drying decreases and the energy of the material is reduced. The rise in temperature leads to the generation of oil-solvents such as carbonization and energy efficiency. For this reason, the present invention detects the change in the drying characteristics of each section according to the drying progress using microwave heating of food waste by using a series of means and calculates the microwave output to be input by appropriately adjusted by drying section to supply drying Find ways to maximize efficiency. The concept of microwave power control of the present invention is not an ON-OFF periodic control concept, but means that the energy input corresponding to the result detected in each drying section is linearly varied.

In the waste disposal apparatus of the present invention, the oscillation device for generating microwaves and the waveguide for smoothly supplying the generated microwaves to the drying chamber (resonant cavity), can contain a certain amount for the drying treatment of food waste and the permeation of microwaves Drying chamber (resonant cavity) for easy loading of drying container and drying container and inducing resonance of microwaves irradiated from waveguide. Drying room is equipped with door for entrance and exit of load, and device including door and drying room is outside of microwave It is composed of a metallic object that microwaves do not penetrate to prevent leakage, and the basic configuration is that a structure for preventing electromagnetic leakage is installed around the door in the part where the door is in contact with the drying chamber in the closed state of the door.

In addition to the basic configuration of the drying chamber, condensate exhaust gas generated during drying and non-condensing wet air is reheated using a heater to enter the drying chamber, and a condenser and condenser that induces condensation in the dry exhaust gas flowing through the circulation blower. Condenser to induce external cooling Stores the cooling blower and condensate from the condenser, and the non-condensing wet air compensates the thermal condition of the condensate reservoir and the flowing air to the hot air generating unit to compensate for the thermal condition of the flowing air. It is installed in the flow environment of dry exhaust.

On the inside and outside walls of the condenser, there is a temperature and humidity sensor that detects the condition of the drying exhaust, analyzes the characteristics of the drying progress section, controls the microwave output and controls the operating status of the entire equipment. Is equipped with a temperature sensor that limits the output of the heater to maintain the set temperature of the flowing air.

Outside the condensate reservoir, a pump is installed to discharge condensate that has collected odor particles during drying to the outside faster and safer than natural discharge by gravity.At the end of the pump, when a certain amount of condensate is stored in the condensate reservoir, the flow is dried and exhausted. A valve is installed to block the flow path to prevent the flow of water to the outside. The outside of the condensate reservoir is connected to the drying chamber so that water is discharged to the outside when the condensate generated in the drying chamber and the water inside the drying chamber are washed. A level sensor is installed inside the condensate reservoir to detect the level of condensate.The valve opens when the top dead center is reached and the pump operates to discharge the condensate.When the bottom dead center is reached, the pump stops to prevent the dry exhaust from flowing out. And close the valve.

When the food waste was dried by using the above-described means of the present invention, the water content after drying was maintained at 9% or less, which is the target water content, even when it was composed of various food mixtures. 80% of domestic food waste is classified as vegetables, grains, and fruits. In case of about 9% of moisture content, calorific value is known to be 3,700 (kcal / kg) on average, which is a value of fuel that is slightly weaker than wood. There is. Therefore, it is expected that if the food waste is dried to maintain a constant moisture content after drying with the drying apparatus according to the present invention, it can be used as an excellent fuel.

As a result of the drying using the means of the present invention, the drying time varies depending on the type of food waste, but the average time was 45 minutes on a 500g basis, which is at least 2 to 9 times the drying time compared to the drying apparatus to which the prior art is applied. Reduced time In addition, there was little odor during drying, and more than 98% of dry moisture was discharged to condensate. Compared to the application of the exhaust filter of the drying apparatus to which the prior art is applied, the drying apparatus of the present invention has an economical efficiency without additional additional costs during use.

As a result of drying using the means of the present invention, the drying efficiency is at least 40% or more, depending on the type of food waste. This improved the drying efficiency by at least 15-30% compared to the drying apparatus to which the prior art is applied.

Hereinafter, with reference to the accompanying drawings showing an embodiment of the present invention will be described in more detail the present invention.

1 is a diagram illustrating the organic operation relationship when drying food waste of the structure invented by the present invention. The flow circuit of exhaust generated during the drying process of food waste by microwave heating has no exposure to an external atmospheric environment. It is a closed circuit, and the dry steam is condensed and discharged to the outside as condensate.The temperature and humidity sensor installed inside and outside the condenser adjusts the microwave output for each drying period to input proper energy, and then determines the time of completion of drying. Features and details of each associated structure are as follows.

3, 4, 5, and 6 are a front view, a right side view, a left side view, and a rear view of the overall configuration of the drying apparatus of the present invention, and FIGS. 7, 8, and 9 are detailed views of important structures. It is shown.

The outer wall of the drying chamber (resonant cavity, 10) constituting the microwave environment except for the installation portion 140 of the front of the drying chamber (resonance cavity 10) is made of a metal material that microwaves can not penetrate and the drying container 50 is accessible to the front ( The part constituting one side of the six sides of the drying chamber is also made of metal, and the drying container 50 which induces microwave absorption by incorporating food waste is easy to permeate microwaves and is heat resistant to withstand temperature and temperature. 300 ℃ or more) is used. In the upper part of the drying chamber 10, there is an opening invented to satisfy the electromagnetic characteristics (impedance) of the microwave while allowing proper irradiation, and the invention allows the microwave to be properly transmitted from the microwave generator 20 to the microwave. The waveguide 40 is speeched, and one of the upper portions is provided with a porous part for exhausting the exhaust gas generated during drying, and a circulating blower 80 for circulating flow of the exhaust gas is speeched outside of the place. On the right side of the drying chamber 10, a porous part is installed so that the circulating flow wet air flows into a hot air (100-120 ° C.) state, and a hot air generating unit 120 that hot-airs the flow wet air is spoken outside. . Of course, the hot air inlet porous portion and the porous portion for exhaust gas discharge is known to be a well-known design structure of the electromagnetic leakage prevention structure. On the inner bottom surface of the drying chamber (10), a study (11) of circular shape is installed so that water is discharged to the outside when the condensate generated during drying and water inside the drying chamber are washed out, and the condensate reservoir (100) is speeched outside of this. The water discharged to the place is discharged to the outside via the pump 110 and the valve 111.

The interlock switch parts 60 and 61 which detect the opening of the door 140 during the operation of the drying device or before the start of the operation of the drying room 10 outside the upper left and right sides of the drying chamber 10 are exposed to the safety accident due to the microwave leakage when the door is opened. It is prevented from occurring.

The door portion 140 installed in the front of the drying chamber 10 to access the drying load is provided with a hook portion 141 in the form of a latch in order to pursue the firmness of the closed state in the interlock switch portions 60 and 61. In the closed state, a shielding structure for preventing electromagnetic leakage is installed around the door, and a sealing part 142 made of rubber material is inserted to prevent leakage of odorous exhaust gas during drying. Keeping up.

A circulating blower 80 is installed at an outer upper portion of the drying chamber 10 to inhale dry exhaust gas generated in the drying chamber during drying and to send it to the condenser 90 to induce an overall circulation flow. The circulating blower 80 communicates with the condenser 90 and has a structure in which the condenser 90 is assembled in an insert form, and an airtight rubber sealing material 81 is installed in the insert portion (see FIG. 7).

As shown in FIG. 7, the condenser 90 is divided into two parts 91 and 92 in consideration of the efficiency and assemblability of condensation, and mechanically assembled to form the condenser 90. Of course, the rubber sealing material for airtightness is inserted in the joining surface of these two parts. The upper part of the condenser 90 is communicated with the circulation blower 80 to introduce the dry steam, and the lower part is communicated with the condensate reservoir 100 so that the condensed water and the uncondensed wet air flow therein. In the condenser 90, a fin-shaped condensation heat exchanger 93 made of aluminum having a high thermal conductivity is in close contact with the condenser outer case 91 made of aluminum to increase condensation efficiency. The condensation heat exchanger 93 of the present invention, which is combined in a plurality of fin shapes, takes the form of three stages in the embodiment of the present invention, but it is clear that multiple stages or one stage having a heat transfer area is possible. The condenser cooling blower 70 for inducing the cooling of the condenser is installed outside the condenser 90. The condensation method of the present invention uses air cooling to reduce energy consumption and cost of parts.

On the outer surface where the condenser outer case 91 and the condensation heat exchanger 93 are in contact with each other, a surface temperature sensor 94 for detecting a surface temperature is installed, and a temperature and humidity sensor 95 inserted into the inside from the outside is installed. In these two places, the operation of the drying apparatus of the present invention is controlled by detecting a change in thermal characteristics of the exhaust gas discharged during drying. For example, when the same microwave energy is supplied when drying food waste, the generation of dry water vapor is slowed down by the slowing down of drying rate during the drying process, which means the reduction of the amount of heat introduced into the condenser. The temperature value in the temperature sensor 94 is lowered and the absolute humidity of the temperature and humidity sensor 95 is reduced, so that the proper drying can be performed only by lowering the microwave power input for drying. For example, a decrease of 1 (g / min) of steam generation per unit indicates a change of about 38 (W) in the latent heat capacity. In the present invention, although the embodiment is set to the condenser 90 to detect the change in the latent heat of evaporation, it includes all that can obtain the effect of the present invention anywhere in the humid air flow path in the drying apparatus.

8 shows a detailed configuration of the condensate reservoir 100, the left side is in communication with the condenser 90, the condensate flowing from the condenser 90 is stored in the lower center along the slope and the non-condensed wet air is on the right side along the inner passage It flows to the part which communicates with the hot air generating part 120. In order to guide the moisture discharged from the drain 11 installed in the lower part of the drying chamber 10 to the storage 100, there is a study 105 connected to the drying chamber, and the central storage unit is configured to discharge the stored condensate to the outside. There is a study 101 in communication with the pump 110, the lower portion of the bottom of the reservoir is formed of a U-shaped space 104 of a lower shape than the bottom reference plane when the foreign matter generated on the flow path is discharged to the outside ( 111) to collect a function to prevent malfunction. This portion 104 is structured to be externally disassembled and includes a structure that can be cleaned regularly.

In the center of the condensate reservoir 100, the water level sensor 103 is installed and when the condensate is stored to the top dead center, the drain valve 111 is opened and the drain pump 110 is operated so that the condensate is discharged to the outside and then the bottom dead center. When it reaches the operation of the drain pump 110 is stopped and the drain valve 111 is closed to block the discharge to the outside of the dry humid air including odor. Here, the bottom dead center of the water level sensor 103 is located at a somewhat higher position than the drain 100 of the reservoir 100 so that the condensate in the reservoir forms a water film, and the outflow of the dry wet air in the process of discharging the condensate until just before the drain valve 111 is blocked. This is a structure that is blocked. All the contact portions in communication with the condensate reservoir 100 includes a rubber-based sealing material is inserted for confidentiality.

Figure 9 shows a detailed view of the hot air generating unit 120 of the present invention is a square hole is installed in the lower portion is in communication with the condensate reservoir (100) to enter the uncondensed humid air flowing through the condensate reservoir (100). , The introduced humid air is heated to 100-120 ° C., which is the thermal reference temperature of the present invention, while passing through the heater 123 installed in the middle, and then passes through the upper square hole communicating with the drying chamber 10. It flows into the drying chamber 10. The rear end of the heater of the hot wind generating unit 120 is provided with a temperature sensor 124 for sensing the temperature of the hot wind to control the output of the heater. All the contact portions communicated with the hot air generating unit 120 includes a rubber-based sealing material is inserted for airtightness.

The detailed means for achieving the object of the present invention has been described in detail above, the control of the proper operation of these components in the drying of food waste using microwave heating using the operation unit 130 located in the main body and FIG. Shows the detailed composition of this

Although the preferred embodiments of the present invention have been described above, these are merely examples and are not intended to limit the present invention, and those skilled in the art to which the present invention pertains have various aspects without departing from the essential characteristics of the present invention. It will be appreciated that eggplant modifications and applications are possible.

Food waste treatment apparatus of the present invention to be efficiently dried to recycle the food waste generated in the home or restaurant.

1 is a schematic diagram of a microwave drying system of the present invention.

2 is a configuration diagram of a drying apparatus operating unit of the present invention.

Figure 3 is a front view of the drying apparatus of the present invention.

4 is a right side view of the drying apparatus of the present invention.

5 is a left side view of the drying apparatus of the present invention.

Figure 6 is a rear view of the drying apparatus of the present invention.

Figure 7 is a detailed view of the condenser of the drying apparatus of the present invention.

Figure 8 is a detailed view of the condensate reservoir of the drying apparatus of the present invention.

9 is a detailed view of the hot air generating unit of the drying apparatus of the present invention.

Claims (3)

In order to dry food waste, microwave heating is used as a main drying heat source, hot air is used as an auxiliary heat source for thermal stability of exhaust flow generated during drying, and the treatment of dry exhaust including odor is condensed and discharged. In the food waste treatment apparatus using microwave heating, the non-condensing dry humid air is circulated, There is a drying chamber (resonant cavity) equipped with a microwave generator and transmission means (waveguides), and can load a container for the composition of the microwave resonance environment and drying processing of food waste, and induces the entry and exit of the drying load into the drying chamber A latch-type door is installed, the door is provided with a shielding structure to prevent electromagnetic leakage in the closed state, and a safety device for blocking the operation of the device in the open state is installed. Pores for inflow and drainage for draining condensate in the drying chamber and water drainage are installed, and a circulating blower is installed outside the drying chamber to discharge and circulate the drying exhaust generated in the drying chamber. To the condensate for the environmental safety of the trapped odor particles of the gas and the dry wet steam discharge An induction air-cooled condenser is installed, and a condensate reservoir for storing and discharging condensate generated from the condenser is installed, and one side of the condensate reservoir is a drain pump for efficient discharge of condensate, and to prevent the discharge of dry wet air during condensate storage. A drainage valve is installed, food waste drying apparatus characterized in that by using the microwave heating is installed to increase the level of the thermal state of the non-condensed wet air to the hot air generating unit for re-introduction into the drying chamber.  According to claim 1, the inside of the condenser uses a high thermal conductivity of aluminum and a plurality of fin-shaped condensation heat exchanger is installed on one side, the outer wall surface is provided with a surface temperature sensing means and penetrated from the outside to the condenser Food waste treatment apparatus characterized by controlling the microwave output for each drying progression section by detecting the temperature change of the dry and wet steam using the two detection means or one by installing the temperature and humidity of the internal flow wet steam.   The condensate reservoir of claim 1 is provided with an inlet hole for introducing condensate and washing water generated in the drying chamber (cavity) to be discharged to the outside. It is installed in a structure that can be periodically disassembled and cleaned from the outside as it is recessed to prevent dust collection.In addition, when the sensor reaches the top dead center with the built-in water level sensor, the drain valve is opened and the drain pump is operated to store the condensate. Is discharged to the outside and the pump stops when the bottom dead center is reached and the drain valve is closed.The condensate level when reaching the bottom dead center is higher than the inlet of the drain pump. Characterized in that it is possible to block the external leakage of the dry humid air Food waste processing equipment.

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