WO2007066988A1

WO2007066988A1 - Apparatus and method for producing energy and manufacturing organic fertilizer by using excretions, waste water and slurry

Info

Publication number: WO2007066988A1
Application number: PCT/KR2006/005273
Authority: WO
Inventors: Yeonggil Ha; Yunha Kim
Original assignee: Korea Environment Technology Co., Ltd.
Priority date: 2005-12-08
Filing date: 2006-12-07
Publication date: 2007-06-14
Also published as: KR20050120618A; KR100704272B1

Abstract

Disclosed is an apparatus for producing energy and an organic fertilizer using livestock excreta, wastewater and slurry. The apparatus includes; a foreign material removal unit removing foreign materials from raw materials input into a charge tank; a fermentation unit supplied with the raw materials from the foreign material removal unit and with high-temperature clean air and heat, and fermenting the raw materials; a slurry dry and transfer unit supplied with the fermented raw materials from the fermentation unit, drying the raw materials using heat, and removing harmful components from the raw materials; a heater unit supplied with methane fermentation gas (MFG) from the fermentation unit, oxygen, and an auxiliary fuel, and burning the supplied mixture to generate heat; an MFG collection tank provided between the fermentation unit and the heater unit so as to collect the MFG produced from the fermentation unit; a boiler unit installed at a rear end of the heater unit, and generating steam; a heat exchanger supplied with waste heat from the boiler unit, exchanging heat with external clean air, and supplying the high-temperature clean air to the fermentation unit; and a separator separating the foreign materials from the raw materials transferred from the slurry dry and transfer unit.

Description

APPARATUS AND METHOD FOR PRODUCING ENERGY AND

MANUFACTURING ORGANIC FERTILIZER BY USING

EXCRETIONS, WASTE WATER AND SLURRY

Technical Field

[1] The present invention relates to an apparatus and method for producing energy and manufacturing an organic fertilizer using excretions, waste water and slurry. More particularly, the present invention relates to an apparatus and method for producing energy using livestock excreta, wastewater, and slurry, not only capable of producing electricity by charging the excreta, wastewater, and slurry, which are used as raw materials into a fermentation tank by indirectly supplying heat to the fermentation tank, fermenting the raw materials at a high speed to generate methane fermentation gas (MFG), mixing the generated MFG with liquefied natural gas (LNG) or liquefied petroleum gas (LPG), operating a heater and a boiler using the mixture to produce steam, and driving a steam turbine using the produced steam, but also for producing an organic fertilizer using livestock excreta, wastewater, and slurry, capable of manufacturing organic fertilizer by drying the fermented raw materials at a high speed using heat.

[2]

Background Art

[3] Generally, when sprayed with Penac-G, the livestock excreta including feces and urine are completely ripened to liquid fertilizer after the fermentation caused by microbes for about two months, which is thereby used as manure. However, livestock wastewater is rich in antibiotics, germicides, and insecticides which are added to fodder, and takes about three months for natural fermentation.

[4] In the case of large-scale livestock farms, the livestock wastewater exceeds 40% of the expenditure for environmental management. The burden on the environmental management expenditure shows a tendency toward gradual increase in the future. In order to treat this wastewater, a method of building a concrete tank underground, storing the wastewater in the concrete tank, and fermenting the wastewater or transferring the wastewater to another place is employed. In the case of the concrete tank, the water-proofing of a concrete structure can prevent the wastewater from leaking. However, because the livestock wastewater has strong corrosiveness, the corrosion of the concrete tank and the resulting cracks are accelerated. In this case, it is almost difficult to repair the cracked concrete tank. When the wastewater flows underground through these cracks, it is not easy to find the wastewater. Furthermore, the soil is contaminated, and it is almost impossible to restore the contaminated soil.

[5] As is well known, water pollution refers to the state where contaminated water beyond natural purification capacity flows into sound water, thereby artificially making the sound water unsuitable for its use. The sources of the water pollution can be generally classified as domestic sewage, industrial wastewater, and an agro- livestock wastewater. Among them, the industrial wastewater is treated through pollution reduction equipment installed according to the water environmental perseverance law, and the domestic sewage is treated through sewage treatment equipment or is released to a public water area such as a river, or, in another method, a sea.

[6] However, the countermeasures against the livestock wastewater leave much to be desired in spite of continuous increase in the demand for domestic animals together with economic growth, and thus the relevant institutes are increasing their efforts to treat this livestock wastewater.

[7] When this livestock wastewater is released without proper treatment because a pollutant load is relatively greater than a wastewater discharge, it causes the water degradation of a river, the eutrophication of a lake, and so on, thereby contaminating a water supply or irrigation water as well as producing offensive odors and harmful insects, and ultimately damaging the environment.

[8] Further, there is difficulty in treating sewage slurry. Thus, in order to minimize these pollution sources, the government launched comprehensive measures for a clean water supply with an enormous investment every year.

[9] However, a livestock wastewater treatment plant has a limitation to the treatment of the livestock wastewater because it is studded with the livestock farms around. In order to overcome this limitation and activate the environmental conservation organic farming, the present invention proposes to rapidly ferment these raw materials such as the livestock excreta, and thereby use the fermented raw materials for the organic farming as well as energizing the fermented raw materials.

[10]

Disclosure of Invention

Technical Problem

[11] The present invention has been made to solve the above problem occurring in the prior art, and an object of the present invention is to provide an apparatus and a method for producing energy and an organic fertilizer using livestock excreta, wastewater and slurry, capable of eliminating the environmental pollution, using the livestock excreta, wastewater and slurry as the raw materials, fermenting the raw materials to obtain the MFG, and energizing methane fermentation gas (MFG) to return to a resource and si- multaneously producing the organic fertilizer to increase farm income.

[12]

Technical Solution

[13] In order to accomplish the above objects, according to one aspect of the present invention, there is provided an apparatus for producing energy and an organic fertilizer using livestock excreta, wastewater and slurry. The apparatus includes; a foreign material removal unit removing foreign materials from raw materials input into a charge tank; a fermentation unit supplied with the raw materials from the foreign material removal unit and with high-temperature clean air and heat, and fermenting the raw materials; a slurry dry and transfer unit supplied with the fermented raw materials from the fermentation unit, drying the raw materials using heat, and removing harmful components from the raw materials; a heater unit supplied with methane fermentation gas (MFG) from the fermentation unit, oxygen, and an auxiliary fuel, and burning the supplied mixture to generate heat; an MFG collection tank provided between the fermentation unit and the heater unit so as to collect the MFG produced from the fermentation unit; a boiler unit installed at the rear end of the heater unit, and generating steam; a heat exchanger supplied with waste heat from the boiler unit, exchanging heat with external clean air, and supplying the high-temperature clean air to the fermentation unit; and a separator separating the foreign materials from the raw materials transferred from the slurry dry and transfer unit.

[14] Here, the fermentation unit may include: a plurality of fermentation tanks

fermenting the raw materials; a heating chamber integrally installed in an outer wall, partitions, and a bottom of the fermentation unit in order to supply the raw materials with heat; and a plurality of fermentation agitator pipes installed in the respective fermentation tanks in order to supply the high-temperature clean air to the respective fermentation tanks from the heat exchanger, and having a plurality of injection nozzles.

[15] Further, the fermentation tanks may include the first fermentation tank, the second fermentation tank, and the third fermentation tank, and communicate therebetween at a predetermined height.

[16] Also, the heating chamber may be connected with a waste heat supply pipe, which is connected with the heat exchanger, on one side thereof, and a water heat discharge pipe, which is connected with a waste heat suction fan, on the other side thereof.

[17] Meanwhile, the heater unit may have a closed structure, and include a plurality of burners that are connected with the MFG collection tank, an oxygen generator, and an auxiliary fuel supply at a front end thereof, and communicate with the boiler unit at the rear end thereof.

[18] Further, the MFG collection tank may be connected with an MFG transfer pipe, which communicates with a closed upper wall of the third fermentation tank. The MFG transfer pipe may be provided with an MFG suction fan on one side thereof in order to draw the MFG; and the MFG collection tank is provided thereabove with an MFG supply pipe.

[19] Also, the slurry dry and transfer unit may be installed across the heater unit, and include: a cylindrical wall provided with a raw material inlet on one side thereof and a raw material outlet on the other side thereof, and having a long, hollow shape in a longitudinal direction; a screw conveyor installed in the cylindrical wall in order to transfer the raw materials; a heat transmitter surrounding around the cylindrical wall in order to transmit the heat from the heater unit to the slurry dry and transfer unit, and being integrally formed with a plurality of gas discharge nozzles that communicate with the cylindrical wall at an upper portion thereof; and a humidity controller is attached to an inner portion of one side of the slurry dry and transfer unit in order to control a speed of the slurry dry and transfer unit according to proper humidity of the raw materials.

[20] Furthermore, the raw material inlet may be connected with a slurry supply pipe, which is connected to a slurry transfer pump in the third fermentation tank in order to supply the raw materials to the slurry dry and transfer unit, and the raw material outlet is connected to the separator.

[21] In addition, the boiler unit may further include a steam storage tank on one side of an upper portion thereof in order to storage steam generated therefrom.

[22] Here, the apparatus may further include a steam turbine, which is connected with the steam storage tank in order to be supplied with steam to thereby produce electricity.

[23] Further, the heat exchanger may include a main body, and a plurality of heat

exchanging pipes in the main body; and the main body may be connected to a waste heat inflow pipe, which communicates with the boiler unit, on one side of an upper portion thereof; the heat exchanging pipes may be connected to one side of the upper portion of the main body, be wound in the main body, and be connected to the other side of the upper portion of the main body; and the main body may be connected with the waste heat supply pipe, which supplies the waste heat to the heating chamber, on the other side of the upper portion thereof; and the main body is provided with an external air inlet at a lower portion thereof, and is connected with a high-temperature clean air supply pipe on the other side thereof.

[24] Also, the apparatus may further include an excipient injector, which is connected to an inlet of the slurry dry and transfer unit to add excipients to the raw materials in order to remove various harmful ingredients contained in the raw materials.

[25] According to another aspect of the present invention, there is provided a method for producing energy and an organic fertilizer using livestock excreta, wastewater and slurry. The method includes the steps of: removing foreign materials from raw materials including livestock excreta, wastewater and slurry; supplying a fermentation unit having a plurality of fermentation tanks with the raw materials from which the foreign materials are removed, and fermenting the raw materials; supplying a heating chamber of the fermentation unit with waste heat; supplying high-temperature clean air through a plurality of fermentation agitator pipes in the fermentation unit in order to facilitate agitating and fermenting the raw materials; storing methane fermentation gas (MFG) generated from the fermentation unit in an MFG collection tank, and supplying a heater unit with the stored MFG; supplying oxygen together with an auxiliary fuel such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG) in order to overcome incomplete combustion, a drawback, of the MFG to effectively burn the MFG; driving the heater unit, a boiler unit, and a steam turbine using the collected MFG, the oxygen, and the auxiliary fuel to thereby produce energy; passing the fermented raw materials through the heater unit, drying the raw materials to produce an organic fertilizer; and exchanging heat through a heat exchanger in order to supply heat required for the fermenting step.

[26]

Advantageous Effects

[27] As described above, the present invention can eliminate environmental pollution, use the livestock excreta, wastewater and slurry as the raw materials, ferment the raw materials to obtain the MFG, and energize the MFG to return to a resource, and simultaneously produce the organic fertilizer to increase the farm income.

[28]

Brief Description of the Drawings

[29] FIG. 1 is a schematic layout view illustrating an apparatus for producing energy as well as manufacturing organic fertilizer using livestock excreta, wastewater, and slurry in accordance with the present invention;

[30] FIG. 2 is a detailed view illustrating the fermentation unit of FIG. 1 ;

[31] FIG. 3 is a detailed view illustrating the heater unit fermentation unit of FIG. 1 ;

[32] FIG. 4 is a detailed view illustrating the slurry dry and transfer unit of FIG. 1 ;

[33] FIG. 5 is a detailed view illustrating the heat exchanger of FIG. 1; and

[34] FIG. 6 is a schematic view illustrating the separator and packing unit of FIG. 1.

[35]

Mode for the Invention

[36] Hereinafter, preferred embodiments according to the present invention will be

described with reference to the accompanying drawings. The terms or words used in the present invention may not be limited to the meanings defined in the dictionary, but can be variously defined by the inventors of this application matching with the scope of the present invention.

[37] Thus, the description and the claim of the present invention will be made with

reference to certain preferred embodiments thereof, and it will be understood by those skilled in the art that various changes in form and details may be made therein.

[38] FIG. 1 is a schematic layout view illustrating an apparatus for producing energy as well as manufacturing organic fertilizer using livestock excreta, wastewater, and slurry in accordance with the present invention.

[39] Herein, the livestock excreta, wastewater and slurry are used as raw materials for producing energy as well as manufacturing organic fertilizer, and thus are referred to as "raw materials."

[40] As illustrated in FIG. 1, the apparatus for producing energy as well as manufacturing organic fertilizer generally includes a foreign material removal unit 10, a fermentation unit 20, a slurry dry and transfer unit 30, a heater unit 40, a boiler unit 50, a heat exchanger 60, and a separator 70.

[41] Further, a methane fermentation gas (MFG) collection tank 80 for collecting MFG produced from the fermentation unit 20 is provided between the fermentation unit 20 and the heater unit 40. The heater unit 40 is provided, at the front thereof with an oxygen generator 90, which enhances combustion efficiency of the MFG, and supplies oxygen so as to obtain higher temperature with a low air ratio. The boiler unit 50 is provided, at the rear thereof, with a steam turbine 100, which is supplied with steam from the boiler unit 50 to thereby produce electricity.

[42] The foreign material removal unit 10 functions to remove foreign materials from raw materials that are charged into a charge tank 11 in order to obtain energy and organic fertilizer. The foreign material removal unit 10 has a combination structure of a rotary roller and a mesh, which is well known to the related art.

[43] As illustrated in FIGS. 1 and 2, the raw materials passing through the foreign

material removal unit 10 is transferred to the fermentation unit 20. The fermentation unit 20 includes a first fermentation tank 230, a second fermentation tank 240, and a third fermentation tank 250. Partitions 215 are mounted between the first fermentation tank 230 and the second fermentation tank 240, and between the second fermentation tank 240 and the third fermentation tank 250. Each partition 250 has a predetermined height.

[44] A heating chamber 220 is installed in an outer wall, the partitions, and a bottom of the fermentation unit 20 in order to supply heat for fermenting the raw materials at a high speed. The heating chamber 220 is supplied with high-temperature heat from the heat exchanger 60. The high-temperature heat is supplied to the fermentation tanks while circulating through the outer wall, the partitions, and the bottom of the fermentation unit 20, and then is discharged from the fermentation unit 20. Further, the first, second and third fermentation tanks 230, 240 and 250 are provided therein with first, second and third fermentation agitator pipes 223, 224 and 225 respectively, and thereby being supplied with high-temperature clean air from the heat exchanger 60. The first, second and third fermentation agitator pipes 223, 224 and 225 are connected to the heat exchanger 60 through a clean air supply pipe 222. The clean air supply pipe 222 is provided with a turbo fan 227 for supplying the high-temperature clean air on one side thereof.

[45] The fermentation agitator pipes 223, 224 and 225 disposed in the fermentation tanks

230, 240 and 250 respectively are each provided with a plurality of air injection nozzles 253, so that the air injection nozzles 253 supply the high-temperature clean air to the fermentation tanks 230, 240 and 250, and thus facilitating agitation and fermentation of the raw materials.

[46] The supply of the high-temperature clean air or heat can accelerate the fermentation of livestock excreta including feces and urine or livestock slurry to remarkably shorten a fermentation period.

[47] The fermentation tanks, the fermentation agitator pipes, and the clean air supply pipe are made of corrosion-resistant material such as SUS316L in order to prevent the raw materials from flowing out by means of corrosion caused by salt or moisture.

[48] Further, in order to process the raw materials in the first, second and third fermentation tanks 250 in that order, the fermentation tanks are mutually connected in series at a proper height. Therefore, when the first fermentation tank 230 is completely filled with the raw materials, the raw materials run over the partition between the first and second fermentation tanks 230 and 240 to flow into the second fermentation tank 240. Subsequently, when the second fermentation tank 240 is completely filled with the raw materials, the raw materials run over the partition between the second and third fermentation tanks 240 and 250 to flow into the third fermentation tank 250. The flow path of the raw materials is shown in FIG. 2.

[49] The heating chamber 220 is connected with a waste heat supply pipe 238, which is connected with the heat exchanger 60, on one side thereof, and a water heat discharge pipe 244, which is connected with a waste heat suction fan 242, on the other side thereof. The waste heat supply pipe 238 supplies waste heat from the heat exchanger 60 to the heating chamber 220, whereas the waste heat suction fan 242 induces suction of the waste heat for the fermentation, and simultaneously supplies gas accompanied with the waste heat after the fermentation to an air pollution protection system, thereby processing the gas into clean gas and then discharging the clean gas into the air.

[50] The heater unit 40 is supplied with MFG from the collection tank 80, and oxygen from the oxygen generator 90, and then heats the MFG and oxygen through burners. At this time, the MFG collection tank 80 is connected with an MFG transfer pipe 261, which communicates with a closed upper wall of the third fermentation tank 250. The MFG transfer pipe 261 is provided with an MFG suction fan 263 on one side thereof in order to draw the MFG. Further, the MFG collection tank 80 is provided thereabove with an MFG supply pipe 265, thereby supplying the collected MFG to the burners of the heater unit 40.

[51] The reason the burners of the heater unit 40 are supplied with oxygen is for

increasing combustion efficiency of the MFG and obtaining high temperature with a low air ratio.

[52] As illustrated in FIG. 3, the heater unit 40 has a closed structure, and includes a plurality of burners 270. Further, the heater unit 40 is connected with the MFG collection tank 80, the oxygen generator 90, and an auxiliary fuel supply 276 at a front end thereof, and communicates with the boiler unit 50 at a rear end thereof.

[53] Subsequently, in order to overcome incomplete combustion, a drawback, of the

MFG to effectively burn the MFG, the burners 270 of the heater unit 40 can be supplied with a mixture of the MFG and liquefied natural gas (LNG) or liquefied petroleum gas (LPG) when supplied with the MFG.

[54] As illustrated in FIGS. 1 and 4, the slurry dry and transfer unit 30 is installed across the heater unit 40. The slurry dry and transfer unit 30 simultaneously performs a drying step of eliminating moisture from the fermented raw materials and a transferring step of transferring the raw materials, thereby producing raw materials of an organic fertilizer.

[55] The slurry dry and transfer unit 30 includes a cylindrical wall 311 having a long, hollow shape in a longitudinal direction, and a screw conveyor 313 in the cylindrical wall 311 in order to transfer the raw materials. The cylindrical wall 311 is integrally formed with a raw material inlet 320 at a front upper portion thereof, and a raw material outlet 330 at a rear lower portion thereof. Further, the cylindrical wall 311 is surrounded by a heat transmitter 340 for transmitting the heat from the heater unit 40 to the slurry dry and transfer unit 30. The heat transmitter 340 is integrally formed with a plurality of gas discharge nozzles 345 communicating with the cylindrical wall 311 at an upper portion thereof.

[56] Further, a humidity controller 315 is attached to an inner portion of one side of the slurry dry and transfer unit 30, so that it can control a speed of the slurry dry and transfer unit 30 according to proper humidity of the raw materials.

[57] The heat transmitter 340 is employed to capture and retain the heat generated from the heater unit 40, and is made of high-strength refractory material containing chrome and nickel. The cylindrical wall 311 of the slurry dry and transfer unit 30 which is surrounded by the heat transmitter 340 is made of stainless steel such as SUS310 having high heat resistance and corrosion resistance, and the screw conveyor 313 in the cylindrical wall 311 is also made of stainless steel such as SUS310 having high heat resistance and corrosion resistance.

[58] The screw conveyor 313 of the slurry dry and transfer unit 30 is closed to protect ingredients of the fermented raw materials. The raw materials transferred by the slurry dry and transfer unit 30 contain gases accompanied with moisture. The moisture contained in the raw materials is removed by heat, and the gases are discharged into the heater unit 40 through the gas discharge nozzles 345. Each gas discharge nozzle 345 is made of stainless steel such as SUS310 having high heat resistance and corrosion resistance.

[59] Some of the burners 270 are automatically ignited or extinguished by the humidity controller 315, which checks the humidity of the raw materials transferred by the slurry dry and transfer unit 30, so that it can ultimately control temperature in the heater unit 40.

[60] Here, the heat transmitter 340 indirectly transmits heat to the slurry dry and transfer unit 30, and the moisture of and gases in the raw materials transferred to the slurry dry and transfer unit 30 are expanded by the heat, and then are discharged through the humidity controller 315. The discharged gases and moisture are burned at the boiler unit 50. The gases and moisture are converted into energy by the combustion, and encounter the heat energized from the MFG to produce more heat.

[61] Further, in order to supply the raw materials to the slurry dry and transfer unit 30, the raw material inlet 320 is connected with a slurry supply pipe 287, which is connected to a slurry transfer pump 286 in the third fermentation tank 250. The raw material outlet 330 is connected to the separator 70 through a separate line.

[62] In addition, in order to remove various harmful ingredients contained in the raw materials, the slurry dry and transfer unit 30 is connected, on an inlet side thereof, with an excipient injector 390, which is used for adding excipients to the raw materials.

[63] The raw materials dried by the slurry dry and transfer unit 30 are discharged to the raw material outlet 330 of the slurry dry and transfer unit 30. The raw materials, which are discharged through the raw material outlet 330 of the slurry dry and transfer unit 30, are packed after their foreign materials are removed by the separator 70.

[64] Further, the boiler unit 50 is installed on the other side of the heater unit 40, and is driven using the heat obtained from the heater unit 40. The boiler unit 50 is connected to a steam storage tank 55 at an upper portion thereof. The steam storage tank 55 is supplied with steam from the boiler unit 50, and sends the steam to the steam turbine 100, so that the steam turbine 100 produces electricity. The steam turbine 100 is well known to those skilled in the art, and so a detailed description thereof will be omitted. [65] Meanwhile, as illustrated in FIG. 5, the heat exchanger 60 includes a main body 61, and a plurality of heat exchanging pipes 65 in the main body 61. The main body 61 is connected to a waste heat inflow pipe 371, which communicates with the boiler unit 50, on one side of an upper portion thereof. The heat exchanging pipes 65 are connected to one side of the upper portion of the main body 61, are wound in the main body 61, and are connected to the other side of the upper portion of the main body 61. The main body 61 is connected with the waste heat supply pipe 238, which supplies the waste heat to the heating chamber 220, on the other side of the upper portion thereof. Further, the main body 61 is provided with an external air inlet 63 at a lower portion thereof, so that external clean air can be introduced into the main body 61. Further, the main body 61 is connected with the high-temperature clean air supply pipe 222, so that high-temperature clean air can be distributed to the first, second and third fermentation tanks 230, 240 and 250.

[66] As to the operation of the heat exchanger 60, the high-temperature waste heat

flowing through the heat exchanging pipes 65 are heat-exchanged with external air introduced into the main body 61. Thereby, the high-temperature clean air is injected into the first, second and third fermentation tanks 230, 240 and 250, and the high- temperature waste heat is supplied to the heating chamber 220 to the heating chamber 220 through the waste heat supply pipe 238.

[67] FIG. 6 illustrates a schematic flow along which an organic fertilizer is produced and packed through a separator in accordance with the present invention.

[68] Hereinafter, the method for producing energy and an organic fertilizer using

livestock excreta, wastewater, and slurry in accordance with the present invention will be described in detail.

[69] Foreign materials are removed from raw materials constituted of livestock excreta, wastewater, and slurry.

[70] The raw materials from which the foreign materials are removed are input into and primarily fermented in the first fermentation tank 230. The raw materials primarily fermented in the first fermentation tank 230 are smoothly transferred to and

secondarily fermented in the second fermentation tank 240. The raw materials secondarily fermented in the second fermentation tank 240 are smoothly transferred to and tertiarily fermented in the third fermentation tank 250.

[71] In the fermentation process, in order to facilitate fermentation by applying the

supplied waste heat to the wall and bottom of each fermentation tank, the waste heat is supplied through the heating chamber 220. Further, high-temperature clean air is supplied into each fermentation tank in order to accelerate agitation and fermentation of the raw materials.

[72] The MFG generated from the third fermentation tank 250 is stored in the MFG collection tank 80, and then is supplied to the heater unit 40.

[73] In order to overcome incomplete combustion, a drawback, of the MFG to effectively burn the MFG, the heater unit 40 is additionally supplied with oxygen, or an auxiliary fuel such as LNG or LPG.

[74] The heater unit 40, the boiler unit 50, and the steam turbine 100 are driven using the collected MFG, the oxygen, and the auxiliary fuel, thereby producing energy.

[75] The fermented raw materials are allowed to pass through the heater unit 40, and thus are dried to produce an organic fertilizer.

[76] In order to supply heat required for the fermentation process, a heat exchanging process of producing high-temperature clean air through the heat exchanger 60 is performed.

[77] The gas used in the present invention is referred to as MFG for the sake of

convenience. The MFG will be described in detail below.

[78] The MFG is a kind of bio gas, which is produced by anaerobic digestion of organic wastes or biomass in the aspect of production. The MFG has a composition of CO , O , N , etc. including CH as a fuel ingredient, and a calorie ranging from about 3,000 to about 6,000 kcal/Nm , so that it may be considered as a low calorific fuel worth sufficient availability. The MFG has not yet been efficiently used. Further, the collected MFG is burnt or left as it is, and thus acting as a pollution factor. There are three plans of taking efficient advantage of the MFG, as follows: a first one of using only the MFG itself as a fuel, wherein there is a limitation in effectively using a large quantity of MFG due to low combustion stability and a limited range of utility; a second one of using a proper mixture of the MFG and existing LNG, wherein the mixture fuel has a calorie lower than that of the LNG, but can remarkably improve incomplete combustion, a drawback, of the MFG, and thus this MFG mixture fuel can be effectively used for a large plant, a large power plant, a district heating and cooling apparatus, and so on; and a third one of using a proper mixture of the MFG and existing LPG, wherein the LPG has twice as high a calorie per unit volume as the main ingredient of urban gas, CH , has, and thus the mixture fuel can be supplied to a gas line in compatibility with the urban gas (Wobbe Index (WI)= 13A), or can be used as an alternative fuel of the urban gas in compatibility with the urban gas (WI=IOA). Table 1 below is a gas composition table.

[79]

[80]

[81]

Claims

[1] An apparatus for producing energy and an organic fertilizer using livestock

excreta, wastewater and slurry, the apparatus comprising:

a foreign material removal unit (10) removing foreign materials from raw materials input into a charge tank (11);

a fermentation unit (20) supplied with the raw materials from the foreign material removal unit (10) and with high-temperature clean air and heat, and fermenting the raw materials;

a slurry dry and transfer unit (30) supplied with the fermented raw materials from the fermentation unit (20), drying the raw materials using heat, and removing harmful components from the raw materials;

a heater unit (40) supplied with methane fermentation gas (MFG) from the fermentation unit (20), oxygen, and an auxiliary fuel, and burning the supplied mixture to generate heat;

an MFG collection tank (80) provided between the fermentation unit (20) and the heater unit (40) so as to collect the MFG produced from the fermentation unit (20);

a boiler unit (50) installed at the rear end of the heater unit (40), and generating steam;

a heat exchanger (60) supplied with waste heat from the boiler unit (50), exchanging heat with external clean air, and supplying the high-temperature clean air to the fermentation unit (20); and

a separator (70) separating the foreign materials from the raw materials transferred from the slurry dry and transfer unit (30).

[2] The apparatus as claimed in claim 1, wherein the fermentation unit (20) includes:

a plurality of fermentation tanks (230, 240, 250) fermenting the raw materials; a heating chamber (220) integrally installed in an outer wall, partitions, and a bottom of the fermentation unit in order to supply the raw materials with heat; and

a plurality of fermentation agitator pipes (223, 224, 225) installed in the respective fermentation tanks (230, 240, 250) in order to supply the high- temperature clean air to the respective fermentation tanks (230, 240, 250) from the heat exchanger (60), and having a plurality of injection nozzles (253).

[3] The apparatus as claimed in claim 2, wherein the fermentation tanks include the first fermentation tank (230), the second fermentation tank (240), and the third fermentation tank (250), and communicate therebetween at a predetermined height. [4] The apparatus as claimed in claim 2, wherein the heating chamber (220) is connected with a waste heat supply pipe (238), which is connected with the heat exchanger (60), on one side thereof, and a water heat discharge pipe (244), which is connected with a waste heat suction fan (242), on the other side thereof.

[5] The apparatus as claimed in claim 1, wherein the heater unit (40) has a closed structure, includes a plurality of burners (270) that are connected with the MFG collection tank (80), an oxygen generator (90), and an auxiliary fuel supply (276) at a front end thereof, and communicates with the boiler unit (50) at the rear end thereof.

[6] The apparatus as claimed in claim 2, wherein: the MFG collection tank (80) is connected with an MFG transfer pipe (261), which communicates with a closed upper wall of the third fermentation tank (250); the MFG transfer pipe (261) is provided with an MFG suction fan (263) on one side thereof in order to draw the MFG; and the MFG collection tank (80) is provided thereabove with an MFG supply pipe (265).

[7] The apparatus as claimed in claim 1, wherein the slurry dry and transfer unit (30) is installed across the heater unit (40), and includes:

a cylindrical wall (311) provided with a raw material inlet (320) on one side thereof and a raw material outlet (330) on the other side thereof, and having a long, hollow shape in a longitudinal direction;

a screw conveyor (313) installed in the cylindrical wall (311) in order to transfer the raw materials;

a heat transmitter (340) surrounding around the cylindrical wall (311) in order to transmit the heat from the heater unit (40) to the slurry dry and transfer unit (30), and being integrally formed with a plurality of gas discharge nozzles (345) that communicate with the cylindrical wall (311) at an upper portion thereof; and a humidity controller (315) is attached to an inner portion of one side of the slurry dry and transfer unit (30) in order to control the speed of the slurry dry and transfer unit (30) according to proper humidity of the raw materials.

[8] The apparatus as claimed in claim 7, wherein the raw material inlet (320) is connected with a slurry supply pipe (287), which is connected to a slurry transfer pump (286) in the third fermentation tank (250) in order to supply the raw materials to the slurry dry and transfer unit (30), and the raw material outlet (330) is connected to the separator (70).

[9] The apparatus as claimed in claim 1, wherein the boiler unit (50) further includes a steam storage tank (55) on one side of an upper portion thereof in order to storage steam generated therefrom.

[10] The apparatus as claimed in claim 9, further comprising a steam turbine (100) connected with the steam storage tank (55) in order to be supplied with steam to thereby produce electricity.

[11] The apparatus as claimed in claim 1, wherein:

the heat exchanger (60) includes a main body (61), and a plurality of heat exchanging pipes (65) in the main body (61); and

the main body (61) is connected to a waste heat inflow pipe (371), which communicates with the boiler unit (50), on one side of an upper portion thereof; the heat exchanging pipes (65) are connected to one side of the upper portion of the main body (61), are wound in the main body (61), and are connected to the other side of the upper portion of the main body (61); and the main body (61) is connected with the waste heat supply pipe (238), which supplies the waste heat to the heating chamber (220), on the other side of the upper portion thereof; and the main body (61) is provided with an external air inlet (63) at a lower portion thereof, and is connected with a high-temperature clean air supply pipe (222) on the other side thereof.

[12] The apparatus as claimed in claim 1 or 7, further comprising an excipient injector

(390) that is connected to an inlet of the slurry dry and transfer unit (30) to add excipients to the raw materials in order to remove various harmful ingredients contained in the raw materials.

[13] A method for producing energy and an organic fertilizer using livestock excreta, wastewater and slurry, the method comprising the steps of:

removing foreign materials from raw materials including livestock excreta, wastewater and slurry;

supplying a fermentation unit (20) having a plurality of fermentation tanks with the raw materials from which the foreign materials are removed, and fermenting the raw materials;

supplying a heating chamber (220) of the fermentation unit (20) with waste heat; supplying high-temperature clean air through a plurality of fermentation agitator pipes in the fermentation unit in order to facilitate agitating and fermenting the raw materials;

storing methane fermentation gas (MFG) generated from the fermentation unit in an MFG collection tank (80), and supplying a heater unit (40) with the stored MFG;

supplying oxygen together with an auxiliary fuel such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG) in order to overcome incomplete combustion, a drawback, of the MFG to effectively burn the MFG; driving the heater unit (40), a boiler unit (50), and a steam turbine (100) using the collected MFG, the oxygen, and the auxiliary fuel to thereby produce energy; passing the fermented raw materials through the heater unit (40), drying the raw materials to produce an organic fertilizer; and

exchanging heat through a heat exchanger (60) in order to supply heat required for the fermenting step.