WO2005015083A2

WO2005015083A2 - System for incinerating waste

Info

Publication number: WO2005015083A2
Application number: PCT/KR2004/001999
Authority: WO
Inventors: Kwang-Nam Choi
Original assignee: Kwang-Nam Choi
Priority date: 2003-08-12
Filing date: 2004-08-09
Publication date: 2005-02-17
Also published as: WO2005015083A3

Abstract

Disclosed is a waste incineration system. Since air nozzle are installed in a bottom wall of a combustion chamber of a primary incinerator to directly inject combustion air into waste, imcomplete combustion of waste is avoided. Because air nozzles for supplying burnt gas into combustion chamber of a secondary incinerator are located along a spiral path to create vortex flow of combustion air and are installed such that they are inclined toward a proceeding direction of the spiral path, noxious subtances are evenly mixed with combustion air and naturally agglomerates into an aggregate, whereby complete combustion of noxious subtances can be ensured. Noxious substances contained in burnt gas discharged from the secondary incinerator and heat of burnt gas are separated and recovered through two stages including a water-cooled type heat exchanger and a cylone separator, whereby heat recovery efficiency is improved and discharge of noxious substances is minimized.

Description

SYSTEM FOR INCINERATING WASTE

Technical Field

The present invention relates- in general, to a waste incineration system and, more particularly, to a waste incineration system which creates a condition (including even mixing of waste with air and a high temperature) appropriate for ensuring complete combustion, to improve waste incineration efficiency and suppress generation of noxious substances to the minimum, filters noxious substances a multitude of times to significantly reduce the emission of noxious substances to the atmosphere, and recovers the heat of burnt gas to provide a supply of steam.

Background Art Recently, with the improvement of living standards, a great number of disposable goods have appeared on markets, as a result of which there is an increase in consumption and waste production. Also, in conformity with changes in customers' tastes and desires, in order to mass- produce and distribute various goods including food items, those goods have been packed in boxes or containers . Moreover, in addition to the original purpose of maintaining freshness of goods and safely delivering goods to customers, unnecessary packaging of goods has increased as a marketing technique, and goods packed in cans, bottles and other convenient disposable containers have become popular, as a consequence of which a huge amount of waste is generated. Meanwhile, as waste material has changed from natural substances to industrial products or by-products made of paper, synthetic resin, glass, metal, etc., limitations necessarily exist in the natural treatment of waste. In order to cope with the serious problems related to the treatment of waste, many countries of the world have established and put in _ force regulations which define responsibility for treatment of waste and strictly restrict manufacture and marketing of products proven to cause environmental pollution. Also, from a technological viewpoint, various attempts have been made to reuse waste as resources for creating energy and treat waste in a safe and efficient manner. So far, incineration and landfill are well established as means to dispose of waste effectively. In Korea, the landfill waste treating method is the most widely used method. However, the landfill method may cause serious environmental problems such as water pollution due to waste landfill leachate. In particular, since it is difficult to secure a wide area to be used for a landfill and obtain the consent of area residents, it is the norm that the landfill method is planned and studied as a matter of national business . For this reason, a reduction in use of the landfill waste disposal means is desired. In response to this demand, recently, the incineration method capable of remarkably reducing the amount of waste and efficiently using heat become more popular than the landfill method. Nevertheless, in the case of the incineration method, since burnt gas contains a substantial amount of noxious substances (such as dioxin, carbon monoxide, soot, dust, and so forth) , various environmental problems such as air pollution are still caused by the incineration method. Various solutions have been disclosed in the art to address the problems caused by the incineration method. A typical solution among them is an incinerator in which combustion air at a high temperature is supplied when incinerating waste, to create combustion conditions including a high temperature and thereby induce complete combustion of waste, so that incomplete combustion under a low temperature condition is avoided, and in which a combustion chamber is divided into two spaces such that waste can be incinerated in one space and noxious substances produced during the incineration of waste can be incinerated a second time in the other space. These days, an integral incinerator system which includes a waste supplier for automatically supplying waste to an incinerator, heat recovery facilities, a cyclone separator for purifying burnt gas, and so on, has been disclosed in the art. Hereafter, in order to help clear understanding of characterizing features of the present invention, the conventional art will be described with reference to the drawings . FIG. 24 is a cross-sectional view illustrating an incinerator of a conventional waste incineration system. As shown in FIG. 24, the conventional incinerator 10 has an incinerator body 11, first and second burners 12 and 13, and a plurality of air nozzles 14. A space defined in the incinerator body 11 is divided by a partition wall lid into two chambers, that is, a lower main combustion chamber 11m in which waste is incinerated and an upper sub combustion chamber llv in which noxious substances contained in burnt gas are incinerated, to provide a double combustion structure. The first and second burners 12 and 13 function to fire the waste in the main combustion chamber 11m and noxious substances in the sub combustion chamber llv, respectively. The plurality of air nozzles 14 supply air from an air chamber 11a, which is heated by combustion heat, into the main combustion chamber 11m and the sub combustion chamber llv. Here, the unexplained reference numeral Hi designates an outside air inlet for introducing outside air into the air chamber 11a, which is connected to a blower for forcibly sucking and supplying forced drafts of outside air. Further, the reference numeral He designates an exhaust port, and the reference numeral lip designates a passage which is defined through the partition wall lid to allow burnt gas produced in the main combustion chamber 11m to flow into the sub combustion chamber llv. However, the conventional incinerator 10 suffers from defects in that, since combustion air supplied to the main combustion chamber 11m cannot be evenly distributed through and deeply mixed with the pile of waste, incomplete combustion frequently results, and it is difficult to thoroughly suppress the production of noxious substances. Of course, combustion efficiency is also worsened. These defects are caused due to the fact that, while waste is concentrated on a bottom wall of the main combustion chamber 11m, the air nozzles 14 are installed on a side wall of the main combustion chamber 11m. That is to say, combustion air is not directly injected into the waste, but is injected into the main combustion chamber 11m to pass over the waste at best. By the fact that noxious substances are incinerated in the sub combustion chamber llv, emission of noxious substances to the atmosphere can be reduced to a certain extent. However, because it is the best way to simply fire and burn noxious substances and supply forced drafts of combustion air into the sub combustion chamber llv, mixing efficiency between noxious substances and combustion air is poor and complete combustion of noxious substances cannot be ensured. That is to say, it is difficult to efficiently incinerate and remove unevenly dispersed noxious substances which enter the sub combustion chamber llv. Therefore, considerable reduction in the emission of noxious substances cannot be anticipated. Also, since the side wall of the main combustion chamber 11m is flat, heat expansion is substantial. For this reason, when the incinerator 10 is used for extended periods of time, the side wall cannot bear the heat of the main combustion chamber 11m, reaching 1, 800~2, 000°C, so that the side wall deforms into an irregularly waved shape or cracks are formed in the side wall to weaken the incinerator 10. Further, while the conventional incinerator 10 is operated, internal pressure is increased to a fairly high value due to a high temperature in the inside of the incinerator 10. In the conventional art, since a measure for reducing pressure is not provided, the likelihood of the incinerator 10 exploding is increased. FIG. 25 is a cross-sectional view illustrating a waste supplier of the conventional waste incineration system. As shown in FIG. 25, the waste supplier 25 comprises a hopper 21, a drum 22 for connecting the hopper 21 to the incinerator 10, a screw 23 installed in the drum 22 and driven to feed waste into the incinerator 10, and a motor

24 for generating driving force to rotate the screw 23. The drum 22 is formed, at an upper wall portion and one end thereof, with an entrance 22i and an exit 22o, respectively. At the entrance 22i, the hopper 21 is connected to the drum 22, and at the exit 22o, the drum 22 is connected to the incinerator 10. The screw 23 comprises a shaft 23s and a blade 23w which is affixed to a circumferential outer surface of the shaft 23s to have a spiral configuration. In the waste supplier 20, as waste is put into the hopper 21 and the motor 24 is operated to rotate the screw 23, the waste is fed through the exit 22o into the incinerator 10 by the driving force of the screw 23. Notwithstanding, the conventional waste supplier 20 is problematic in that, since the screw 23 is installed in the drum 22, if waste having a size larger than a radial distance Di' between the shaft 23s and an inner surface of the drum 22 is introduced into the drum 22, that waste is jammed between the shaft 23s and the drum 22 to hinder the feeding of other waste into the incinerator 10. The problem is worsened due to a narrow pitch Pi' of the blade 23w. Accordingly, in the case of bulky waste, it is necessary to perform an operation of cutting the bulky waste into pieces before incinerating the waste, incurring additional time and expense. In addition, since the exit 22o of the drum 22 always communicates with the incinerator 10, heat generated in the incinerator 10 may enter the drum 22 through the exit 22o, whereby the screw 23 is likely to be deformed by heat and waste in the drum 22 is likely to burn, causing a fire in the drum 22. FIG. 26 is a cross-sectional view illustrating a cyclone separator of the conventional waste incineration system. As shown in FIG. 26, the conventional cyclone separator 26 comprises a separator body 31, a plurality of cyclone units 32, an exhaust pipe 33, a water jacket 34, a water supply pipe 35 and a water discharge . pipe 36. The cyclone body 31 defines a separation chamber 31s into which burnt gas discharged from the incinerator 10 flows. The plurality of cyclone units 32 are arranged at an upper end of the separation chamber 31s to purify the burnt gas. The exhaust pipe 33 is installed above the separator body 31 to discharge purified gas to the atmosphere. The water jacket 34 is formed around the separator body 31 to accommodate water therein. The water supply pipe 35 functions to supply water into the water jacket 34. The water discharge pipe 36 functions to discharge water heated in the water jacket 34 to a desired place. The separator body 31 is defined at a lower end thereof with a noxious substance outlet port 31e. Below the noxious substance outlet port 31e, there is positioned a collection box 37 for collecting noxious substances passing through the noxious substance outlet port 31e. In the cyclone separator 30, burnt gas flowing into the separation chamber 31s is guided to and purified by the cyclone units 32, and then discharged to the atmosphere. Noxious substances separated from the burnt gas fall and pass through the noxious substance outlet port 31e, and then collect in the collection box 37. Water supplied into the water jacket 34 through the water supply pipe 35 receives the heat of the burnt gas through a wall of the separator body 31, is converted into warm water, and then discharged through the water discharge pipe 36. Nonetheless, the conventional cyclone separator 30 is not free from shortcomings in that, because water accommodated in the water jacket 34 receives the heat of the burnt gas through the wall of the separator body 31, it takes a long time to heat water to a predetermined temperature. In other words, due to the fact that the surface area for heat transfer is insufficient compared to the amount of water accommodated in the water jacket 34, heat recovery efficiency is low. Thus, only tepid water, rather than hot water, can be supplied and it is impossible to provide steam. Further, since the water jacket 34 is formed around the separator body 31, the cyclone separator 30 occupies a large volume and a wide installation space is required. Also, in the conventional cyclone separator 30, when it is used for extended periods of time, soot and the like, contained in the burnt gas, adheres to an inner surface of the separator body 31 to block heat transfer, further deteriorating heat transfer efficiency. This defect also serves as a main reason for the fact that it takes a long time to heat water accommodated in the water jacket 34 to a predetermined temperature. In the meanwhile, in the conventional waste incineration system, because the incinerator 10, the cyclone separator 30, and the other component elements constitute a single waste incineration system, a path through which burnt gas is finally discharged to the atmosphere is lengthened, and thereby, internal pressure in the waste incineration system is likely to be excessive.

Disclosure of the Invention

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a waste incineration system wherein a waste incineration procedure is divided into primary and secondary procedures for incinerating waste and noxious substances contained in burnt gas, respectively, such that combustion air is directly supplied to waste during primary incineration, and combustion air creates a vortex flow when secondarily incinerating noxious substances, and wherein a heat recovery procedure for recovering heat from burnt gas produced by waste incineration and separating noxious substances still remaining in the burnt gas is divided into primary and secondary procedures, whereby the generation of noxious substances and the discharge of noxious substances to the atmosphere can be maximally suppressed. Another object of the present invention is to provide a waste incineration system wherein a wall of a combustion chamber is formed to have an embossed portion so that heat deformation and crack formation can be avoided. Another object of the present invention is to provide a waste incineration system wherein a waste supplier is constructed to push waste into an incinerator so that an entire inside space of a drum can be used as a passage for feeding waste, whereby it is possible to supply waste in large volumes. Another object of the present invention is to provide a waste incineration system wherein a waste supplier is constructed such that a waste outlet of a drum can be opened and closed as desired, whereby it is possible to prevent heat from an incinerator from entering into the drum. A further object of the present invention is to provide a waste incineration system wherein a water pipe is directly installed on an inner surface of a separator body of a cyclone separator to allow water to flow through the water pipe, whereby a volume of the cyclone separator can be reduced, and, since the water pipe serves as a medium for transferring heat of burnt gas to the water, the heat transfer area between water and the burnt gas is increased to improve heat recovery efficiency. Yet another object of the present invention is to provide a waste incineration system wherein particles and soot which adhere to the water pipe and hinder heat transfer are removed by the injection of steam, whereby it is possible to prevent heat transfer efficiency from deteriorating. Still another object of the present invention is to provide a waste incineration system wherein a measure for maintaining constant internal pressure is provided in an incinerator, whereby it is possible to avoid explosion due to an increase in internal pressure. Yet still another object of the present invention is to provide a waste incineration system wherein discharge of burnt gas is facilitated so that the burnt gas can be quickly discharged to the atmosphere, whereby it is possible to keep internal pressure of the entire system constant. In order to accomplish the above objects, according to one aspect of the present invention, there is provided a waste incineration system, comprising: a waste supplier for supplying waste in a manner such that the waste is pushed by the waste supplier; a primary incinerator defined therein with a primary combustion chamber for receiving waste from the waste supplier and having an air chamber defined around the primary combustion chamber, to incinerate waste while air supplied in the air chamber and heated by the heat of the primary combustion chamber is injected into the primary combustion chamber; a secondary incinerator defined therein with a secondary combustion chamber into which burnt gas produced in the primary combustion chamber flows, to incinerate noxious substances contained in the burnt gas while receiving air from the air chamber and supplying received air to the secondary combustion chamber; a water- cooled type heat exchanger for primarily recovering heat by passing burnt gas flowing therein from the secondary incinerator through metal tubes which are installed through a heat exchange chamber filled with water and for primarily separating noxious substances contained in the burnt gas by causing the noxious substances to drop by a difference in specific gravity into a noxious substance collection chamber defined below the heat exchange chamber; and a cyclone separator for secondarily separating, by centrifugal force, noxious substances contained in burnt gas which flows from the water-cooled type heat exchanger into a separation chamber defined therein and then discharging the burnt gas through an exhaust pipe to the atmosphere, and secondarily recovering heat through a water pipe which is installed in the separation chamber and receives water from the heat exchange chamber, wherein the primary incinerator includes a plurality of first air nozzles which are installed in a bottom wall of the primary combustion chamber to receive and inject air supplied from the air chamber and the secondary incinerator includes a plurality of second air nozzles which are installed in a side wall of the second combustion chamber to receive and inject air supplied from the air chamber, and wherein the second air nozzles are obliquely installed such that their injection holes are directed toward an exhaust port of the secondary incinerator to promote the discharge of burnt gas, are located along a spiral path to create a vortex flow in the secondary combustion chamber, and are inclined toward a proceeding direction of the spiral path. According to another aspect of the present invention, an embossed portion is formed in the shaft of a coil on a side wall of the primary combustion chamber such that a valley portion is also formed on the side wall of the primary combustion chamber. According to another aspect of the present invention, an anti-explosion port for reducing a pressure of the primary combustion chamber is defined in the primary incinerator; and anti-explosion port opening and closing means is installed in the anti-explosion port to open the anti-explosion port when a pressure of the primary combustion chamber is greater than a predetermined value 5 and close the anti-explosion port when a pressure of the primary combustion chamber is less than the predetermined value. According to another aspect of the present invention, the waste supplier comprises a waste input hopper; a waste

10 feeding drum defined on an upper wall thereof with a waste inlet at which the waste input hopper is connected to the waste feeding drum and at one end thereof with a waste outlet at which the waste feeding drum is connected to the primary incinerator; a waste pusher installed in the waste

15. feeding drum such that it can be slidably reciprocated, to push waste into the primary incinerator; and pusher driving means for moving the waste pusher forward to push waste into the primary incinerator and backward to its original position.

20 According to another aspect of the present invention, a waste outlet opening and closing plate for opening and closing the waste outlet is installed through the waste feeding drum such that it can be pushed into and pulled out of the waste feeding drum to close and open the waste

25 outlet, and an air injection mechanism is installed between the waste outlet opening and closing plate and the primary incinerator to inject air and thereby form an air curtain in the waste feeding drum. According to another aspect of the present invention, a burnt gas inlet pipe for introducing burnt gas from the water-cooled type heat exchanger into the separation chamber of the cyclone separator is connected to an upper end of the cyclone separator in a tangential direction; and the water pipe is also installed in the burnt gas inlet pipe to extend from the separation chamber toward the burnt gas inlet pipe. According to another aspect of the present invention, at least one first soot blower is installed at an upper end of the separation chamber to inject steam downward to thereby clean the water pipe. According to still another aspect of the present invention, the burnt gas inlet pipe is defined at one end thereof with an opening which is to be opened and closed by an opening and closing door; and a second soot blower is installed outside the opening to inject steam through the opening to thereby clean the water pipe installed in the burnt gas inlet pipe. According to yet still another aspect of the present invention, an air injection pipe is installed through a wall of the exhaust pipe to inject air supplied from an ejector blower toward an outlet of the exhaust pipe, to thereby facilitate discharge of burnt gas. Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: FIG. 1 is a systematic diagram illustrating a waste incineration system according to the present invention; FIG. 2 is a cross-sectional view illustrating a waste supplier of the waste incineration system shown in FIG. 1; FIG. 3 is a cross-sectional view illustrating an operating state of the waste supplier shown in FIG. 2; FIG. 4 is a cross-sectional view taken along the line A-A of FIG. 2; FIG. 5 is a perspective view illustrating a waster pusher of the waste supplier shown in FIG. 2; FIG. 6 is a cross-sectional view taken along the line B-B of FIG. 2; FIG. 7 is a perspective view illustrating a waste outlet opening and closing plate of the waste supplier shown in FIG. 2; FIG. 8 is a cross-sectional view illustrating a primary incinerator of the waste incineration system shown in FIG. 1; FIG. 9 is a perspective view illustrating a primary combustion chamber of the primary incinerator shown in FIG. 8; FIG. 10 is a perspective view illustrating another example of the primary combustion chamber shown in FIG.. 9; FIG. 11 is a cross-sectional view taken along the line C-C of FIG. 8; FIG. 12 is an enlarged view for the part ^ΛD' of FIG. 8; FIG. 13 is an enlarged view for the part E' of FIG.

8; FIG. 14 is a cross-sectional view illustrating a secondary incinerator of the waste incineration system shown in FIG. 1; FIG. 15 is an enlarged view for the part ^λF' of FIG.

14; FIG. 16 is a partially cut-away perspective view illustrating the secondary incinerator shown in FIG. 14; FIG. 17 is a cross-sectional view taken along the line G-G of FIG. 14; FIG. 18 is a cross-sectional view illustrating a water-cooled type heat exchanger of the waste incineration system shown in FIG. 1; FIG. 19 is a cross-sectional view illustrating a cyclone separator of the waste incineration system shown in FIG. 1; FIG. 20 is a cross-sectional view illustrating an operating state of the cyclone separator shown in FIG. 19; FIG. 21 is a front view illustrating an opening and closing door of the cyclone separator shown in FIG. 19 and driving means thereof; FIG. 22 is a cross-sectional view taken along the line H-H of FIG. 21; FIG. 23 is an exploded perspective view illustrating a second soot blower of the cyclone separator shown in FIG. 19 and its related component elements; FIG. 24 is a cross-sectional view illustrating an incinerator of a conventional waste incineration system; FIG. 25 is a cross-sectional view illustrating a waste supplier of the conventional waste incineration system; and FIG. 26 is a cross-sectional view illustrating a cyclone separator of the conventional waste incineration system. <Description of Reference Numerals for Main Component Elements of the Drawings> 100: waste supplier

110: waste input hopper 120: waste crusher 121: shaft 122: circular cutter

123: shaft rotation means 123g: gears 123m: gear driving motor 130: waste cutter 131: lower cutter 132: upper cutter 140: waste feeding drum 140e: waste outlet

140t: waste inlet 150: waste pusher

151: waste pushing plate

152 : waste inlet opening and closing plate 153: reinforcing plate 155: pusher driving means

160: waste outlet opening and closing plate

161: refractory layer 170: air injection mechanism

200: primary incinerator

210e: exhaust port of the primary incinerator 210h: anti-explosion port

211: primary combustion chamber 211e: embossed portion

211f: bottom of primary combustion chamber

211v: valley portion

211w: side wall of the primary combustion chamber 212: first combustion air supply chamber

215: air chamber 240: first air nozzles

240i: suction hole of first air nozzle

240j : injection hole of the first air nozzle

250: anti-explosion port opening and closing means 260: exhaust promotion mechanism

300: secondary incinerator

310e: exhaust port of the secondary incinerator

311: secondary combustion chamber

311w: wall of the secondary combustion chamber 312: second combustion air supply chamber

330: second air nozzles 330i: suction hole of second air nozzle

330j : injection hole of the second air nozzle

400: air-cooled type heat exchanger

411: heat exchange chamber 412: collection chamber 420: metal tubes

500: cyclone separator

501: ejection blower 502: air injection pipe

511: separation chamber

511w: wall of separation chamber 520: burnt gas inlet pipe

52Ow: wall of the burnt gas inlet pipe

521: opening

522 : opening and closing door

540: exhaust pipe 540o: outlet of the exhaust pipe

550: water pipe 560: first soot blower

570: second soot blower

580: soot blower moving means

590: soot blower rotating means 591: rotation plate 592: rotation plate driving motor

Best Mode for Carrying Out the Invention

Reference will now be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components . As shown in FIG. 1, a waste incineration system according to the present invention comprises a waster supplier 100, a primary incinerator 200 for incinerating waste received from the waste supplier 100, a secondary incinerator 300 for incinerating various noxious substances contained in burnt gas produced in the primary incinerator 200, and a water-cooled type heat exchanger 400 and a cyclone separator 500 for twice separating noxious substances still remaining in the burnt gas discharged from the secondary incinerator 300 and recovering heat to provide steam. FIGs. 2 and 3 are cross-sectional views illustrating an entire structure of the waste supplier 100 before and during operation, respectively. As shown in FIG. 2, the waste supplier 100 comprises a waste input hopper 110, a waste crusher 120, a waste cutter 130, a waste feeding drum 140, a waste pusher 150, and pusher driving means 155. The waste input hopper 110 has a funnel-shaped configuration. The waste crusher 120 and waste cutter 130 function to crush and cut into pieces waste put into the waste input hopper 110. The waste feeding drum 140 defines a feeding passage 140p for feeding waste without loss into the primary incinerator 200, which waste is crushed and cut into pieces to be reduced in its volume. The waste pusher 150 is installed in the waste feeding drum 140 such that it can be slidably reciprocated in the feeding passage 140p, to push and supply waste into the primary incinerator 200. The pusher driving means 155 functions to move the waste pusher 150 forward to thereby push waste into the primary incinerator 200 and backward to its original position. The waste feeding drum 140 comprises an elongate linear duct (see FIG. 6) which defines the feeding passage 140p having a rectangular cross-sectional shape. The waste feeding drum 140 is defined at an upper wall thereof with a waste inlet 140t which opens upward, and at one end thereof with a waste outlet 14Oe, in a manner such that the waste input hopper 110 is connected to the waste feeding drum 140 at the waste inlet 140t and the waste feeding drum 140 is connected to the primary incinerator 200 at the waste outlet 140e. FIG. 4 is a cross-sectional view taken along the line A-A of FIG. 2, illustrating a structure of the waste crusher 120. The waste crusher 120 cooperates with the waste cutter 130 to crush and cut bulky waste into pieces so that the waste can be properly fed through the waste feeding drum 140. As shown in FIG. 4, the waste crusher 120 comprises a pair of shafts 121, a plurality of circular cutters 122, and shaft rotation means 123. The pair of shafts 121 are installed in the waste input hopper 110 in a direction perpendicular to a waste input direction and aligned parallel to each other. The plurality of circular cutters 122 are secured to the shafts 121 such that the circular cutters secured to the respective shafts 121 are alternated with each other in a staggered manner. The shaft rotation means 123 rotates the pair of shafts 121 in opposite directions so that waste is drawn between the circular cutters 122 secured to the respective shafts 121 and crushed by the shearing force of the circular cutters 122. The circular cutters 122 are eccentrically secured to their respective shafts 121 in a manner such that, when viewed in a cross-section, each two-dot chain line ^λW' , which runs in an axial direction of each shaft 121 and connects outer edges of the circular cutters 122 secured to the same shaft 121, defines a wave-shaped contour. For this reason, the circular cutters 122 can be smoothly and naturally rotated in a state wherein they are alternated with each other in a staggered manner, to crush waste. Meanwhile, in order to ensure that waste is properly guided to be drawn between the circular cutters 122 and effectively crushed, while not shown in the drawings, hook elements each having a pointed end can be fastened to a circumferential outer surface of the circular cutter 122. The shaft rotation means 123 comprises a pair of gears 123g, each of which is secured to one end of each of the shafts 121 outside the waste input hopper 110 to be meshed with each other, and a gear driving motor 123m for rotating one of the gears 123g. At this time, the gear driving motor 123m can be installed to directly transmit its power to the gear 123m. Alternatively, as shown in FIG. 3, the gear driving motor 123m can be installed to transmit its power to the gear 123g by way of a chain transmission constituted by a sprocket wheel 123s and a chain 123c. The waste cutter 130 comprises a pair of cutters for cutting, through their shearing function, long pieces of waste which are caught between the waste input hopper 110 and the waste feeding drum 140, among waste which is to pass through the waste inlet 140t and drop into the waste feeding drum 140 in a state crushed by the waste crusher 120. That is to say, the waste cutter 130 comprises a lower cutter 131 which is mounted to an upper end of the waste pusher 150 such that an edge of the lower cutter 131 is directed forward, to be integrally reciprocated with the waste pusher 150, and an upper cutter 132 which is installed at one edge of the waste inlet 104t of the waste feeding drum 140 such that the upper cutter 132 is positioned in opposition to the lower cutter 131, to be passed by the lower cutter 131 to thereby cut waste into pieces. FIGs. 5 and 6 illustrate the waste pusher 150. FIG. 5 is a perspective view and a FIG. 6 is a cross-sectional view taken along the line B-B of FIG. 2. As shown in FIGs. 5 and 6, the waste pusher 150 comprises a waste push plate 151, a waste inlet opening and closing plate 152, and a pair of reinforcing plates 153. The waste push plate 151 has a cross-sectional shape which corresponds to that of the feeding passage 140p of the waste feeding drum 140 and is slidably driven to push waste into the primary incinerator 200. The waste inlet opening and closing plate 152 is connected to an upper end of the waste push plate 151 to extend therefrom rearward so that it closes the waste inlet 140t when it is moved forward integrally with the waste push plate 151. The pair of reinforcing plates 153 are connected to both side edges of the waste push plate 151 and the waste inlet opening and closing plate 152 to support the waste inlet opening and closing plate 152 with respect to the waste push plate 151. The lower cutter 131 is fastened to an upper end of the waste push plate 151 to be flush with an upper surface of the waste inlet opening and closing plate 152. The pusher driving means 155 for driving the waste pusher 150 structured as mentioned above comprises a cylinder housing 155h and a piston 155r. That is to say, the pusher driving means 155 is installed rearward of the waste pusher 150 and comprises a hydraulic cylinder having the piston rod 155r which is connected at a distal end thereof to a rear surface of the waste push plate 151. Meanwhile, a waste outlet opening and closing plate 160 for opening and closing the waste outlet 140e is installed through the waste feeding drum 140 such that it can be pulled out of and pushed into the waste feeding drum 140 to open and close the waste outlet 140e to prevent heat of the primary incinerator 200 from entering the waste feeding drum 140 through the waste outlet 140e. An air injection mechanism 170 is installed between the waste outlet opening and closing plate 160 and the primary incinerator 200 to inject air and thereby form an air curtain in the waste feeding drum 140. Therefore, the waste outlet opening and closing plate 160 can be cooled by the presence of the air curtain, and, when the waste outlet opening and closing plate 160 is opened, heat of the primary incinerator 200 is prevented from entering the waste feeding drum 140 by the presence of the air curtain. The waste outlet opening and closing plate 160 is driven by driving means 165 which comprises a hydraulic cylinder, to be reciprocated along a straight path. As shown in FIG. 7, a refractory layer 161 which is formed of castable refractories is attached to a front surface of the waste outlet opening and closing plate 160 to prevent the waste outlet opening and closing plate 160 from being deformed by heat of the primary incinerator 200. At this time, it is sufficient that the refractory layer 161 is attached only to the surface which is directly exposed to heat, as shown in the drawing. The air injection mechanism 170 comprises a plurality of nozzles. In the present embodiment, the nozzles are installed in a circumferential direction of the waste feeding drum 140 to be spaced apart one from another at a predetermined interval, so that a powerful air curtain can be created in the waste feeding drum 140. In FIGs. 2 through 7, the unexplained reference numeral 180 designates a hopper opening and closing plate for opening and closing a passage of the waste input hopper 110, which is installed below the waste crusher 120 to be pushed into and pulled out of the waste input hopper 110. The reference numeral 185 designates driving means for driving the hopper opening and closing plate 180, which comprises a hydraulic cylinder. The reference numeral 190 designates casings for accommodating and protecting the driving means 155, 165 and 185 for the waste pusher 150, waste outlet opening and closing plate 160 and hopper opening and closing plate 180, respectively. FIG. 8 is a cross-sectional view illustrating a structure of the primary incinerator 200. As shown in FIG. 8, the primary incinerator 200 comprises a primary incinerator body 210, a first burner 220, blower means 230, and a plurality of first air nozzles 240. The primary incinerator body 210 is installed in a longitudinal direction and defines therein a primary combustion chamber 211 for receiving waste from the waste supplier 100 and incinerating the waste. An air chamber 215 is defined in the primary incinerator body 210 around and above the primary combustion chamber 211. The first burner 220 functions to fire and burn the waste supplied to the primary combustion chamber 211 of the primary incinerator body 210. The blower means 230 and plurality of first air nozzles 240 function to suck air of the air chamber 215 which is heated by combustion heat via a side wall 211w of the primary combustion chamber 211 and forcibly supply sucked air into the primary combustion chamber 211. Further, the primary incinerator body 210 is defined with a waste inlet opening 210s for receiving waste, an exhaust port 210e for discharging burnt gas, and an outside air inlet hole 210i for allowing flow of outside air into the air chamber 215. The waste feeding drum 140 of the waste supplier 100 is connected to the waste inlet opening 210s, and a first discharge guide pipe PI for guiding the flow of burnt gas into the secondary incinerator 300 is connected to the exhaust port 210e. FIG. 9 is a perspective view schematically illustrating a structure of the primary combustion chamber 211. As shown in FIG. 9, the primary combustion chamber 211 is formed to have a cylindrical configuration. An embossed portion 211e is formed on an inner surface of the side wall 211w of the primary combustion chamber 211 to define a spiral winding configuration in the shape of a coil extending in an axial direction of the primary incinerator body 210. A valley portion 211v is defined on the inner surface of the side wall 211w of the primary combustion chamber 211 due to the presence of the embossed portion 2He. Due to a configurational characteristic of the embossed portion 211e and the valley portion 211v which are formed on the side wall 211w of the primary combustion chamber 211, heat resistance of the primary combustion chamber 211 is improved, and ^' heat expansion of the primary combustion chamber 211 is minimized. FIG. 10 is a perspective view illustrating another example of the primary combustion chamber 211. Due to the fact that the embossed portion 211e can also be formed on an outer surface of the side wall 211w of the primary combustion chamber 211, advantages can be accomplished due to reinforced configurational characteristic of the embossed portion 211e. A first combustion air supply chamber 212 is defined below the primary combustion chamber 211. in the primary incinerator 210 to receive from the blower means 230 air of the air chamber 215. The first air nozzles 240 are installed in a bottom wall 211f of the primary combustion chamber 211 to receive air from the first combustion air supply chamber 212 and inject received air into the primary combustion chamber 211. FIGs. 11 and 12 illustrate a configuration, an arrangement, an installation structure, etc. of the first air nozzles 240. FIG. 11 is a cross-sectional view taken along the line C-C of FIG. 8, and FIG. 12 is an enlarged view for the part ^λD' of FIG. 8. As shown in FIGs. 11 and 12, the first air nozzles

240 are located on the bottom wall 211f of the primary combustion chamber 211 to be uniformly distributed over an entire area of the bottom wall 211f in a radial direction. Each first air nozzle 240 is installed in the bottom wall 211f of the primary combustion chamber 211 such that its suction hole 240i and injection hole 24Oj are respectively exposed to the first combustion air supply chamber 212 and the primary combustion chamber 211. In order to prevent waste from clogging the injection hole 240j, a plurality of injection holes 240j are defined on a circumferential portion of each first air nozzle 240. Meanwhile, an anti-explosion port 210h is defined at a center portion of an upper wall of the primary incinerator 210 so that the primary combustion chamber 211 can be directly communicated with the outside as occasion demands. Anti-explosion port opening and closing means 250 is installed in the anti-explosion port 210h to open and close the anti-explosion port 210h. The anti-explosion port opening and closing means 250 comprises a pressure reducing valve for opening the anti- explosion port 210h when a pressure of the primary combustion chamber 211 rises over a predetermined temperature due to the expansion of burnt gas while incinerating waste and for closing the anti-explosion port 210h when a pressure of the primary combustion chamber 211 decreases below the predetermined temperature. In the anti- explosion port opening and closing means 250, force is applied to the valve by a spring, a diaphragm, or the like, to close the anti-explosion port 210h. In this state, if a pressure of the primary combustion chamber 211 increases over the predetermined temperature, the pressure biases the valve to allow the discharge of burnt gas, and if a pressure of the primary combustion chamber 211 decreases below the predetermined temperature, the force for closing the anti-explosion port 21Oh overcomes the pressure of the primary combustion chamber 211 to allow the anti-explosion port 210h to be closed. The blower means 230 comprises a blower 231, a combustion air suction pipe 232, and a first combustion air supply pipe 233. The blower 231 is composed of a casing and an impeller, and so forth, installed in the casing. The combustion air suction pipe 232 connects the blower 231 to the air chamber 215 so that the blower 231 can suck air from the air chamber 215. The first combustion air supply pipe 233 connects the blower 231 to the first combustion air supply chamber 212 so that air sucked by the blower 231 can be supplied to the first combustion air supply chamber 212. FIG. 13 is an enlarged view for the part Ε^f of FIG. 8. As shown in FIG. 13, an exhaust promotion mechanism 260 is installed in the exhaust port 210e of the primary incinerator 200. The exhaust promotion mechanism 260 functions to inject air toward the location where burnt gas is discharged, so that the burnt gas can be forcibly discharged out of the primary incinerator 200 by virtue of air injection force from the exhaust promotion mechanism

260. The exhaust promotion mechanism 260 comprises at least one nozzle. Of course, an injection hole 260j of the nozzle is directed toward the discharge location of the burnt gas. FIG. 14 is a cross-sectional view illustrating the secondary incinerator 300 of the waste incineration system. As shown in FIG. 14, the secondary incinerator 300 comprises a secondary incinerator body 310, a second burner

320, and a plurality of second air nozzles 330. The secondary incinerator body 310 is installed in a transverse direction and defines therein a cylindrical secondary combustion chamber 311. The second burner 320 functions to fire and burn noxious substances contained in the burnt gas which is introduced into the secondary combustion chamber 311 of the secondary incinerator body 310 from the first incinerator 210. The plurality of second air nozzles 330 function to receive heated air from the air chamber 215 by the medium of the blower 231 and then inject the received air into the secondary combustion chamber 311. The secondary incinerator body 310 is defined at one end thereof with a burnt gas inlet 310i for allowing introduction of burnt gas from the primary combustion chamber 211 into the secondary combustion chamber 311. At the burnt gas inlet 310i, the first discharge guide pipe PI which is connected to the exhaust port 210e of the first incinerator 200 is connected to the second incinerator 300. The secondary incinerator body 310 is defined at the other end thereof with an exhaust port 310e where a second discharge guide pipe P2 for guiding the introduction of burnt gas into the water-cooled type heat exchanger 400 is connected to the secondary incinerator 300. In the secondary incinerator body 310, a second combustion air supply chamber 312 for receiving air from the air chamber 215 via the blower 231 is defined around the secondary combustion chamber 311. The second air nozzles 330 are installed in a side wall 311w of the secondary combustion chamber 311 to receive air from the second combustion air supply chamber 312 and inject the received air into the secondary combustion chamber 311. The second combustion air supply chamber 312 is connected to the blower 231 by the medium of a second combustion air supply pipe 340 to receive air from the blower 231. FIGs. 15 through 17 illustrate a configuration, an arrangement, an installation structure, etc. of the second air nozzles 330. FIG. 15 is an enlarged view of the part F' of FIG. 14, FIG. 16 is a partially cut-away perspective view illustrating the secondary incinerator 300, and FIG. 17 is a cross-sectional view taken along the line G-G of FIG. 14. The second air nozzles 330 are installed in the side wall 311w of the secondary combustion chamber 311. As shown in FIG. 15, each second air nozzle 330 is installed in the side wall 311w of the secondary combustion chamber 311 such that its suction hole 330i and injection hole 33j are respectively exposed to the second combustion air supply chamber 312 and the secondary combustion chamber 311. Each second air nozzle 330 is installed in a manner such that its injection hole 330j is inclined at a predetermined angle toward the exhaust port 310e of the secondary incinerator body 310 to promote discharge of the burnt gas through the exhaust port 31Oe. In addition, as shown in FIGs. 16 and 17, the second air nozzles 330 are located along a spiral path X' which extends in an axial direction of the secondary incinerator body 310, to create a vortex flow in burnt gas and combustion air and allow burnt gas and combustion air to evenly mix with each other. Further, the second air nozzles 330 are installed such that they are inclined by a predetermined angle toward a proceeding direction of the spiral path. For instance, the second air nozzle 330 is inclined by 30° toward the exhaust port 310e when measured from a vertical line (see FIG. 15) , and is also inclined toward the proceeding direction of the spiral path by 30° when measured between axes ^λY' of two adjoining air nozzles 330 (see FIG. 17) . FIG. 18 is a cross-sectional view illustrating a structure of the water-cooled type heat exchanger 400. The water-cooled type heat exchanger 400 functions to recover heat of burnt gas discharged from the secondary incinerator 300 and introduced therein and to separate noxious substances using a difference in specific gravity. As shown in FIG. 18, the water-cooled type heat exchanger 400 comprises a heat exchanger body 410 and a plurality of metal tubes 420. The inside space of the heat exchanger body 410 is divided into three spaces, that is, upper, middle and lower spaces . The upper space is divided again into left and right spaces . In the heat exchanger body 410, the middle space serves as a heat exchange chamber 411 in which water for recovering heat of burnt gas is accommodated, the lower space serves as a collection chamber 412 in which noxious substances contained in the burnt gas are collected, and the upper space serves as a burnt gas inlet chamber 413 and a burnt gas discharge chamber 414. The metal tubes 420 allows burnt gas discharged from the secondary incinerator 300 and introduced into the burnt gas inlet chamber 413 to be discharged to the cyclone separator 500 after sequentially passing through the heat exchange chamber 411, the collection chamber 412, the heat exchange chamber 411 and the burnt gas discharge chamber 414. To this end, the metal tubes 420 comprise a plurality of first metal tubes 421 which pass through the heat exchange chamber 411 and are connected at both ends thereof to the burnt gas inlet chamber 413 and the collection chamber 412 so that burnt gas can flow into the collection chamber 412 via the heat exchange chamber 411, and a plurality of second metal tubes 422 which pass through the heat exchange chamber 411 and are connected at both ends thereof to the collection chamber 412 and the burnt gas discharge chamber 414 so that the burnt gas introduced into the collection chamber 412 after passing through the first metal tubes 421 can flow into the burnt gas discharge chamber 414 via the heat exchange chamber 411. The heat exchanger body 410 is defined with a burnt gas inlet port 413i for introducing burnt gas into the burnt gas inlet chamber 413 and a burnt gas outlet port 414e for discharging burnt gas flowing into the burnt gas discharge chamber 414 toward the cyclone separator 500. The second discharge guide pipe P2 which is connected to the exhaust port 310e of the secondary incinerator 300 is connected to the burnt gas inlet port 413i, and a third discharge guide pipe P3 for introducing burnt gas into the cyclone separator 500 is connected to the burnt gas outlet port 414e. FIGs. 19 and 20 are cross-sectional views illustrating a structure of the cyclone separator 500 before and during operation, respectively. As shown in FIGs. 19 and 20, the cyclone separator 500 comprises a separator body 510, a burnt gas inlet pipe 520, a plurality of cyclone units 530, an exhaust pipe 540, and a water pipe 550. The separator body 510 defines a separation chamber 511. The burnt gas inlet pipe 520 connects the separator body 510 to the water-cooled type heat exchanger 400 to introduce burnt gas from the water- cooled type heat exchanger 400 into the separation chamber 511. The plurality of cyclone units 530 are installed at an upper end of the separation chamber 511 to separate noxious substances and thereby purify the burnt gas . The exhaust pipe 540 has an elongate shape and is installed above the separator body 510 to discharge burnt gas purified by the cyclone units 530 to the atmosphere. The water pipe 550 is installed on inner surfaces of the separation chamber 511 and the burnt gas inlet pipe 520. The separator body 510 has a cylindrical portion 510b and a frusto-conical portion 510r which is formed integrally at a lower end of the cylindrical portion 510b and has a gradually decreased diameter. At a lower end of the frusto-conical portion 510r, there is defined a noxious substance discharge opening 512 for discharging noxious substances such as dust, separated from the burnt gas. A rotary valve 513 is installed in the noxious substance discharge opening 512 to serve as opening and closing means . The burnt gas inlet pipe 520 is bent at a right angle. Both ends of the burnt gas inlet pipe 520 are connected to the third discharge guide pipe P3 which is connected to the burnt gas outlet port 414e of the water- cooled type heat exchanger 400, and the cylindrical portion 510b of the separator body 510, respectively. The burnt gas inlet pipe 520 is connected to an upper end of the cylindrical portion 510b of the separator body 510 in a tangential direction. The water pipe 550 is installed to extend from a lower end of the separation chamber 511 to the inner surface of the burnt gas inlet pipe 520. The water pipe 550 comprises a pipe member which has a desired diameter so that water flowing into the water pipe 550 can be heated by heat of the burnt gas to be capable of simultaneously providing hot water and steam. The water pipe 550 itself serves as a heat transfer medium to directly transfer heat of the burnt gas to water to thereby heat the water. Accordingly, since the water pipe 550 itself serves by itself as a heat transfer medium for transferring heat of burnt gas to water, a contact area between the heat transfer medium and the water is increased to improve heat recovery efficiency. The water pipe 550 is installed on the inner surface 511w of the separation chamber 511 and the inner surface 520w of the burnt gas inlet pipe 520, in the shape of a coil which is wound along a spiral path. Both ends of the water pipe 550 are exposed to the outside to receive water from the heat exchange chamber 411 of the water-cooled type heat exchanger 400 and circulate water again into the heat exchange chamber 411. A first soot blower 560 is installed at the upper end of the separation chamber 511 to inject steam into the water pipe 550 arranged in the separation chamber 511 and thereby clean the water pipe 550. The burnt gas inlet pipe 520 bent at a right angle is defined with an opening 521 which is to be opened and closed by an opening and closing door 522. A second soot blower 570 is installed outside the opening 521 to inject steam through the opening 521 to thereby clean the water pipe 550 installed in the burnt gas inlet pipe 520. The first soot blower 560 functions to clear noxious substances such as soot which are accumulated on and adhere to a surface of the water pipe 550 while falling toward the noxious substance discharge opening 512 after being separated from burnt gas. In the present embodiment, a pair of first soot blowers 560 are installed at an upper end of the separator body 510. In a preferred embodiment, each first soot blower 560 is installed such that only a distal end thereof projects into the separation chamber 511 to prevent the soot blower 560 from being deformed by heat of the burnt gas. FIGs. 21 and 22 illustrate the opening and closing door 522 and its related component elements. FIG. 21 is a front view, and FIG. 22 is a cross-sectional view taken along the line H-H of FIG. 21. As shown in FIGs. 21 and 22, the opening and closing door 522 is installed by a pair of guide projections 523 which are formed on the burnt gas inlet pipe 520 at left and right sides of the opening 521, such that it can be slidably moved to open and airtightly close the opening 521. The opening and closing door 522 is operated by door driving means 600, to open and close the opening 521. While it is sufficient that the door driving means 600 has a construction capable of operating the opening and closing door 522, in the present embodiment, the door driving means 600 comprises a worm 601 which is installed at a side of the opening and closing door 522 in a parallel relationship to a moving direction of the opening and closing door 522 and has the shape of an elongate external thread, a worm wheel 602 which is installed on the burnt gas inlet pipe 520 to be meshed with the worm 601 and is composed of a gear, for example, a helical gear, and a worm wheel driving motor 603 for driving the worm wheel 602. FIG. 23 is an exploded perspective view illustrating the second soot blower 570 and its related component elements . Similarly to the first soot blower 560, the second soot blower 570 functions to clear noxious substances such as soot, which adhere to the surface of the water pipe 550. As can be readily seen from FIG. 23, the second soot blower 570 is moved forward by soot blower moving means 580 for moving the second soot blower 570 through the opening 521 into the burnt gas inlet pipe 520 along a straight path and injecting steam toward the water pipe 550. The soot blower moving means 580 comprises a hydraulic cylinder which is composed of a cylinder housing, a piston and a piston rod to convert hydraulic energy into linear kinetic energy. The reason why the second soot blower 570 is installed to be moved into and out of the burnt gas inlet pipe 520, unlike the first soot blower 570, is that a temperature of burnt gas in the burnt gas inlet pipe 520 reaches 1,800°C which can seriously deform the second soot blower 570, whereas a temperature of burnt gas in the exhaust pipe 540 adjacent to which the first soot blower 560 is installed is only about 400°C due to heat recovery by the water pipe 550. In this regard, a temperature of burnt gas when introduced into the separation chamber 511 reaches about 700°C. Soot blower rotation means 590 is installed between the second soot blower 570 and the soot blower moving means 580, to rotate the second soot blower 570 about an axis, so that steam injected from the second soot blower 570 can be evenly distributed over a wide area. The soot blower rotation means 590 comprises a rotation plate 591 on which the second soot blower 570 is eccentrically installed at a predetermined separation from a center thereof, and a rotation plate driving motor 592 which is installed at a distal end of a piston rod of the soot blower moving means (hydraulic cylinder) 580 to rotate the rotation plate 591. It is to be readily understood that the rotation plate 591 can be installed concentrically with a motor shaft of the rotation plate driving motor 592 as shown in the drawing or can be eccentrically installed in opposition to the second soot blower 570. The soot blower moving means 580 is locked by bolts to ends of a pair of first elongate brackets 585 which are vertically installed at both sides of the opening 521, to be supported by the first elongate brackets 585. The soot blower rotation means 590 is supported by a pair of second brackets 595 which are locked to each other by bolts while they surround both sides of the rotation plate driving motor 592. The second brackets 595 are formed with a pair of guide flanges 595g which are fitted into guide slots 585s defined in the pair of first brackets 585, respectively, in a lengthwise direction. An air injection pipe 502 is installed through a wall of the exhaust pipe 540 to receive air from an ejector blower 501 and inject received air toward an outlet 540o of the exhaust pipe 540, to thereby forcibly discharge burnt gas to the atmosphere and facilitate the discharge of burnt gas. In FIGs. 18 through 23, the unexplained reference numeral L0 designates a water supply pipe for supplying water into the heat exchange chamber 411, LI and L2 first and second circulation pipes for circulating water from the heat exchange chamber 411 through the water pipe 550 again into the heat exchange chamber 411, and L3 a drain pipe for discharging steam. Further, the reference numeral 514 designates a partition wall for partitioning the separation chamber 511 so that burnt gas newly introduced into the cyclone units 530 and burnt gas discharged toward the exhaust pipe 540 after being purified by the cyclone units 530 are prevented from being mixed with each other. The drawing reference numeral 505 designates a collection box for collecting noxious substances discharged through the noxious substance discharge opening 512. Hereafter, operations of the waste incineration system according to the present invention, constructed as mentioned above, will be described in detail. After supplying fuel into the first and second burners 220 and 320 of the primary and secondary incinerators 200 and 300, by operating the first and second burners 220 and 320, the primary and secondary combustion chambers 211 and 311 are heated so that temperatures rise. When temperatures of the primary and secondary combustion chambers 211 and 311 are sufficiently high (for example, 600°C in the case of the primary combustion chamber and 850°C in the case of the secondary combustion chamber) , the blower 231, the discharge promotion mechanism 260 and the ejector blower 501 are operated. Also, water is supplied into the water supply pipe L0 so that water is accommodated to a desired level in the heat exchange chamber 411 of the water-cooled type heat exchanger 400. At this time, water of the heat exchange chamber 411 flows into the water pipe 550 of the cyclone separator 500 through the first circulation pipe LI, and the water flowing in the water pipe 550 is circulated again into the heat exchange chamber 411 through the second circulation pipe L2. The waste pusher 150 of the waste supplier 100 is moved rearward to open the waste inlet 140t. The waste outlet opening and closing plate 160 and the hopper opening and closing plate 180 are operated to close the waste outlet 140e and the passage of the waste input hopper 110, respectively. The air injection mechanism 170 is handled to inject air, to thereby form the air curtain between the waste outlet opening and closing plate 160 and the primary incinerator 200. In a state wherein preparations for incinerating waste are completed as described above, waste is put into the waste input hopper 110 so that waste can be fully piled up on the crusher 120. Then, the corresponding driving means 185 is operated to pull the hopper opening and closing plate 180 out of the passage of the waste input hopper 110 so that the passage of the waste input hopper 110 is opened. Simultaneously, the gear driving motor 123m of the shaft rotation means 123 is operated. By this, power of the gear driving motor 123m is transmitted to the gears 123g to rotate the shafts 121 to which the gears 123g are secured. Accordingly, two grouped circular cutters 122 secured to the respective shafts 121 are rotated in opposite direction to each other. Thereby, waste is drawn between the two groups of circular cutters 122 to be crushed to a desired size, and then drops through the waste inlet 140t to be gathered in the waste feeding drum 140. In the above-described procedure, since the line ^λW' connecting the outer edges of the circular cutters 122 secured to the same shaft 121 defines a wave-shaped contour, the circular cutters 122 can be smoothly and naturally rotated. Moreover, by controlling a rotation speed of the shafts 121 to accelerate or decelerate a rotational speed of the circular cutters 122 or stop the circular cutters

122, it is possible to adjust a supply speed and an amount of waste which is introduced into the feeding drum 140. Next, the corresponding driving means 165 is operated to pull the waste outlet opening and closing plate 160 out of the waste feeding drum 140 so that the waste outlet 140e is opened, and the pusher driving means 155 is operated to extend the piston rod 155r from the cylinder housing 155h.

At this time, heat of the primary combustion chamber 21 is prevented from entering the waste feeding drum 140 through the waste outlet 14Oe through the blocking function of the air curtain which is formed by the air injection mechanism 170, and the waste pusher 150 is gradually moved forward toward the waste outlet 14Oe by energy of the moving piston rod 155r. As the waste pusher 150 is moved forward in this way, waste which is gathered in the waste feeding drum 140 is pushed by the waste push plate 151 to be fed toward the waste outlet 140e, and the waste inlet 140t is gradually closed by the waste inlet opening and closing plate 152. The lower cutter 131 of the waste cutter 130, which is mounted to the waste pusher 150, passes the upper cutter 132. By this, large pieces of waste which are caught between the waste input hopper 110 and the waste feeding drum 140, among waste which is to pass through the waste inlet 140t and drop into the waste feeding drum 140 in a state crushed by the waste crusher 120, are cut into pieces. Hence, since all of the waste put into the waste input hopper 110 is appropriately prepared to be fed through the feeding passage 14Op of the waste feeding drum 140, it is not necessary for a worker to perform an operation for crushing and cutting the waste into pieces in advance . Once the waste pusher 150 is completely moved forward, waste is discharged through the waste outlet 140e to be accumulated in the primary combustion chamber 211, and the waste inlet 140t is closed to keep waste from dropping into the waste feeding drum 140. Thereafter, if the movement of waste into the primary combustion chamber 211 is completed, the pusher driving means 155 is operated to return the pusher 150 to its original position, and the corresponding driving means 165 is operated to cause the waste outlet opening and closing plate 160 to close the waste outlet 140e. At this time, the waste inlet 140t is opened to allow waste to drop into the waste feeding drum 140. Heat of the primary combustion chamber 211 is prevented from entering the waste feeding drum 140 through two stages, that is, by the waste outlet opening and closing plate 160 and the air curtain formed by the air injection mechanism 170. The waste outlet opening and closing plate 160 is prevented from being deformed by the cooling function of the air curtain and the heat blocking function by the refractory layer 161. Waste accumulated in the primary combustion chamber 211 is fired by the first burner 220, and the air introduced into the air chamber 215 through the outside air inlet hole 210i receives and is heated by heat of the primary combustion chamber 211 by the medium of the side wall 211w of the primary combustion chamber 211. The blower 231 sucks heated air from the air chamber 215 through the combustion air suction pipe 232 and supplies the sucked air to the first combustion air supply chamber 212 through the first combustion air supply pipe 233. Therefore, air supplied to the first combustion air supply chamber 212 is injected into waste residing in the primary combustion chamber 211 through the first air nozzles 240 installed in the bottom wall 211f of the primary combustion chamber 211. The combustion air is directly injected into the waste accumulated on the bottom wall 211f of the primary combustion chamber 211 to evenly and deeply penetrate into the waste, whereby complete incineration of waste is ensured. By continuously incinerating waste, a temperature of the primary combustion chamber reaches 1, 800-2, 000°C. At this time, by the presence of the embossed portion 211e formed on the side wall 211w of the primary combustion chamber 211, the primary combustion chamber 211 is prevented from being deformed, and cracks are not formed in the side wall 211w. Also, if a pressure is excessively raised due to a high temperature, the pressure reducing valve 250 is operated to open the anti-explosion port 210h. Accordingly, the pressure is reduced, and then, the pressure reducing valve 250 is operated to close the anti-explosion port 210h again. Meanwhile, burnt gas produced in the primary combustion chamber 211 is discharged through the exhaust port 210e of the primary incinerator 200 and then introduced into the secondary combustion chamber 311 through the first discharge guide pipe PI which connects the first and second incinerators 200 and 300 to each other. At this time, burnt gas is forcibly discharged by air injected by the discharge promotion mechanism 260. Noxious substances contained in burnt gas introduced into the secondary combustion chamber 311 are burned by the second burner 320, and the blower 231 sucks air from the air chamber 215 and then supplies sucked air to the second combustion air supply chamber 312 through the second combustion air supply pipe 340. Thus, air supplied into the second combustion air supply chamber 312 is injected into the secondary combustion chamber 311 through the second air nozzles 330 which are installed on the side wall 311w of the secondary combustion chamber 311. At this time, due to the fact that the second air nozzles 330 are located along a spiral path and installed such that they are inclined toward the exhaust port 310e of the secondary combustion chamber 311 and toward a proceeding direction of the spiral path, a vortex flow is created toward the exhaust port 310e. For this reason, noxious substances are evenly mixed with combustion air and naturally agglomerates into an aggregate. As a consequence, complete combustion of noxious substances is ensured and combustion efficiency is improved. Burnt gas discharged through the exhaust port 310e of the secondary incinerator 300 is introduced into the burnt gas inlet chamber 413 through the second discharge guide pipe P2 which connects the secondary incinerator 300 and the water-cooled type heat exchanger 400. The burnt gas passes through the heat exchange chamber 411 via the first metal tubes 421 and is introduced into the collection chamber 412. Then, the burnt gas flows into the burnt gas discharge chamber 414 after passing through the heat exchange chamber 411 via the second metal tubes 422. Consequently, heat of burnt gas is transferred to water accommodated in the heat exchange chamber 411 while flowing in the first and second metal tubes 421 and 422 to pass through the heat exchange chamber 411. Noxious substances contained in burnt gas flowing toward the second metal tubes 422 cannot be introduced into the second metal tubes 422 due to a difference in specific gravity and therefore drop to be collected in the collection chamber 412. Next, burnt gas flowing into the burnt gas discharge chamber 414 is introduced into the separation chamber 511 of the cyclone separator 500 after sequentially passing through the third discharge guide pipe P3 for connecting the water-cooled type heat exchanger 400 to the cyclone separator 500 and the burnt gas inlet pipe 520. Since the burnt gas inlet pipe 520 is connected to the separator body 510 in a tangential direction, a vortex flow is created in the burnt gas introduced into the separation chamber 511 as described above, to cause the burnt gas to flow on the inner surface 511w of the separation chamber 511. While the burnt gas flows in the cyclone separator 500, the burnt gas is introduced into the cyclone units 530. At this time, the burnt gas is separated from remaining noxious substances by the centrifugal force of the cyclone units 530. For reference, as shown in FIG. 19, the cyclone unit 530 has a cylindrical part and a conical part. Burnt gas is supplied from a side wall of the cylindrical part in a tangential direction and rotatingly flows downward along an inner wall of the cylindrical part. Then, the burnt gas enters the conical part and continues to flow downward. After reaching a lower end thereof, it flows upward at a center portion to be discharged out of an exit. During this process, noxious substances remaining in the burnt gas are moved in a radial direction under the action of centrifugal force while being rotated, to become separated from the burnt gas and gather on a wall of the conical part. Then, the noxious substances are lowered on the wall of the conical part along a spiral path, and are discharged through an apex of a conical configuration. Thereafter, the burnt gas discharged from the cyclone units 530 flows into the exhaust pipe 540. At this time, the burnt gas purified as described above is quickly discharged to the atmosphere with the aid of air injected by the air injection pipe 502 through a blowing function of the ejector blower 501 toward the outlet 540o of the exhaust pipe 540. This discharge promotion function by the ejector blower 501 and the air injection pipe 502 is combined with provision of the anti-explosion part 210h and the discharge promotion mechanism 260, to maintain a constant pressure in the entire system including the primary and secondary incinerators 200 and 300, the water-cooled type heat exchanger 400 and the cyclone separator 500. On the other hand, noxious substances separated in the cyclone units 530 drop to be accumulated at the lower end of the separation chamber 511, that is, on the rotary valve 513. By operating the rotary valve 513, the noxious substances are discharged through the noxious substance discharge opening 512 to be collected in the collection box 505. In the above described procedure, water which is supplied into the water pipe 550 from the heat exchange chamber 411 (that is, which is heated to some extent in the heat exchange chamber) receives the heat of burnt gas flowing in the separation chamber 511, which approaches 700°C, by the medium of the water pipe 550 to be primarily heated and then receives heat of the burnt gas inlet pipe

520, which approaches about 1,800°C to be secondarily heated. Accordingly, since water flowing through the water pipe 550 is already heated once and the water pipe 550 itself serves as a heat transfer medium, a heat transfer area is significantly increased to quickly heat water to a high temperature. At this time, a part of water is vaporized into steam. Steam is discharged through the drain pipe L3. In the case that soot and the like is attached to the water pipe 550 and the water pipe 550 is polluted thereby, the wheel driving motor 603 of the door driving means 600 is operated. At this time, by the power of the wheel driving motor 603, the worm wheel 602 is rotated, and the worm 601 meshed with the worm wheel 602 is moved along a straight path. By this, the opening and closing door 522 to which the worm 601 is installed is moved while being guided by the guide projections 523 along a straight path in the same direction, to open the opening 521. Then, by operating the soot blower moving means 580, the second soot blower 570 is moved through the opening 521 into the burnt gas inlet pipe 520. Thereafter, the first and second soot blowers 560 and 570 and the rotation plate driving motor 592 of the soot blower rotation means 590 are operated. By this, the first soot blower 560 injects steam to the water pipe 550 located in the separation chamber 511, and the rotation plate driving motor 592 rotates the rotation plate 591 by its own power. The soot blower 570 which is eccentrically installed on the rotation plate 591 is rotated about a motor shaft of the rotation plate driving motor 592 to inject steam to the water pipe 550 located in the burnt gas inlet pipe 520. At this time, soot, etc. attached to the water pipe 550 is cleared by the cleaning function of the steam. When incineration of waste is completed, operations of component elements except the blower 231 and the ejector blower 501 are interrupted, and the first and second burners 220 and 230 run in an idle state such that the fuel supply is blocked to gradually reduce the temperatures of the primary and secondary combustion chambers 211 and 311. Then, when the temperatures of the primary and secondary combustion chambers 211 and 311 reach suitable terminal temperatures (for example, 100~150°C) , the first and second burners 220 and 320, the blower 231 and the ejector blower 501 are interrupted in their operations. By interrupting operations of the first and second burners 220 and 320, the blower 231 and the ejector blower 501 at a low temperature, it is possible to prevent damage or breakdown of the system, which is otherwise caused due to high temperatures of the primary and secondary combustion chambers 211 and 311. Industrial Applicability

As apparent from the above descriptions, the waste incineration system according to the present invention provides advantages in that, since air nozzles are installed in a bottom wall of a combustion chamber of a primary incinerator to directly inject combustion air into waste, incomplete combustion of waste can be avoided and generation of noxious substances can be kept at a minimum. Also, because air nozzles for supplying burnt gas into a combustion chamber of a secondary incinerator are located along a spiral path to create a vortex flow of combustion air and are installed such that they are inclined toward a proceeding direction of the spiral path, noxious substances contained in burnt gas which flow from the primary incinerator into the secondary incinerator are evenly mixed with combustion air and naturally agglomerates into an aggregate, whereby complete combustion of noxious substances can be ensured. In addition, due to the fact that noxious substances contained in burnt gas discharged from the secondary incinerator and heat of burnt gas are separated and recovered through two stages including a water-cooled type heat exchanger and a cyclone separator, heat recovery efficiency is improved and discharge of noxious substances to the atmosphere can be minimized. Meanwhile, in the primary incinerator, due to a configurational characteristic of an embossed portion formed on a side wall of the primary combustion chamber, heat resistance is improved and it is possible to prevent heat deformation of the side wall and crack formation in the side wall. Further, because an anti-explosion port is defined in the primary incinerator and anti-explosion port opening and closing means is provided to open the anti-explosion port when a pressure in the primary combustion chamber increases, explosion of the primary incinerator due to an increase in a pressure can be avoided. In a waste supplier, waste introduced into a feeding drum is supplied to the primary incinerator in a manner such that the waste is pushed by a pusher from a position which is opposite to a waste outlet of the feeding drum.

Therefore, since an entire space defined in the feeding drum serves as a passage for feeding waste, even bulky waste having a relatively large volume can be properly supplied to the primary incinerator. Further, because waste put into a hopper is crushed by a crusher and long pieces of waste are cut by a cutter, it is not necessary to perform an advance operation of cutting the waste into pieces and the long waste can be fed into the primary incinerator as it is, saving time and expense . Moreover, by controlling a rotation speed of circular cutters constituting the crusher, to rotate the circular cutters at a high speed or stop the circular cutters, it is possible to adjust a speed and an amount of waste which is introduced into the feeding drum. At this time, the circular cutters are secured to a pair of shafts so that outer edges of circular cutters secured to the same shaft define a wave-shaped contour. Thus, it is possible to smoothly and naturally rotate the circular cutters secured to the pair of shafts in an alternately staggered manner. Furthermore, since the waste outlet of the feeding drum can be opened and closed by an opening and closing plate, it is possible to prevent heat of the primary incinerator from entering the feeding drum and fire from occurring in the feeding drum due to the inflow of heat. Besides, due to a blocking function of an air curtain which is formed by an air injection mechanism, it is possible to more effectively prevent heat of the primary incinerator from entering the feeding drum, and, by a cooling function of the air curtain, a degree to which the waste outlet opening and closing plate is heated can be reduced. In a cyclone separator, in place of the conventional water jacket, since a water pipe is installed on an inner surface of a separation chamber defined in a separator body and an inner surface of a burnt gas inlet pipe, a volume of the cyclone separator can be reduced. Also, because heat of the burnt gas is transferred to and heats water flowing through the water pipe by the medium of the water pipe, a heat transfer area between water and the heat transfer medium is increased to improve heat recovery efficiency. Accordingly, water can be quickly heated to a high temperature to be converted into hot water, and a portion of water can be changed in its phase into steam to be supplied to a desired place. Also, the water pipe can be easily cleaned by a first soot blower which is installed at an upper end of the separation chamber and a second soot blower which is installed outside an opening defined through the burnt gas inlet pipe. Further, since an air injection pipe is installed through a wall of an exhaust pipe to inject air supplied from an ejector blower to thereby facilitate the discharge of burnt gas, a pressure of the entire system can be decreased.

Claims

1. A waste incineration system, comprising: a waste supplier for supplying waste in a manner such that the waste is pushed by the waste supplier; a primary incinerator defined therein with a primary combustion chamber for receiving waste from the waste supplier and having an air chamber defined around the primary combustion chamber, to incinerate waste while air supplied in the air chamber and heated by heat of the primary combustion chamber is injected into the primary combustion chamber; a secondary incinerator defined therein with a secondary combustion chamber into which burnt gas produced in the primary combustion chamber flows, to incinerate noxious substances contained in the burnt gas while receiving air from the air chamber and supplying received air into the secondary combustion chamber; a water-cooled type heat exchanger for primarily recovering heat by passing burnt gas flowing therein from the secondary incinerator through metal tubes which are installed through a heat exchange chamber filled with water and for primarily separating noxious substances contained in the burnt gas by causing the noxious substances to drop by a difference in specific gravity into a noxious substance collection chamber defined below the heat exchange chamber; and a cyclone separator for secondarily separating, by centrifugal force, noxious substances contained in burnt gas which flows from the water-cooled type heat exchanger into a separation chamber defined therein and then discharging the burnt gas through an exhaust pipe to the atmosphere, and secondarily recovering heat through a water pipe which is installed in the separation chamber and receives water from the heat exchange chamber, wherein the primary incinerator includes a plurality of first air nozzles which are installed in a bottom wall of the primary combustion chamber to receive and inject air supplied from the air chamber and the secondary incinerator includes a plurality of second air nozzles which are installed in a side wall of the second combustion chamber to receive and inject air supplied from the air chamber, and wherein the second air nozzles are obliquely installed such that their injection holes are directed toward an exhaust port of the secondary incinerator to promote discharge of burnt gas, are located along a spiral path to create a vortex flow in the secondary combustion chamber, and are inclined toward a proceeding direction of the spiral path.

2. The waste incineration system according to claim 1, wherein the waste supplier comprises: a waste input hopper; a waste feeding drum defined on an upper wall thereof with a waste inlet at which the waste input hopper is connected to the waste feeding drum and at one end thereof with a waste outlet at which the waste feeding drum is connected to the primary incinerator; a waste pusher installed in the waste feeding drum such that it can be slidably reciprocated, to push waste into the primary .incinerator; and pusher driving means for moving the waste pusher forward to push waste into the primary incinerator and backward to its original position.

3. The waste incineration system according to claim 2, wherein the waste supplier further comprises: a waste crusher for crushing waste which is put into the waste input hopper; and a waste cutter for cutting waste into pieces, which is crushed by the waste crusher.

4. The waste incineration system according to claim

3, wherein the waste crusher comprises: a pair of shafts rotatably installed in the waste input hopper; a plurality of circular cutters secured to the pair of shafts such that the circular cutters secured to the respective shafts are alternated with each other in a staggered manner, to cut waste into pieces; and shaft rotation means for rotating the pair of shafts in opposite directions.

5. The waste incineration system according to claim 4, wherein the circular cutters are eccentrically secured to the respective shafts so that outer edges of the circular cutters secured to the same shaft define a wave- shaped contour when viewed in a cross-section.

6. The waste incineration system according to claim 4, wherein the shaft rotation means comprises: gears respectively secured to one ends of the shafts to be meshed with each other; and a gear driving motor for rotating one of the gears.

7. The waste incineration system according to claim 3, wherein the waste cutters comprise: a lower cutter mounted to an upper end of the waste pusher such that an edge of the lower cutter is directed forward, to be integrally reciprocated therewith; and an upper cutter installed at an edge of the waste inlet of the waste feeding drum such that the upper cutter is positioned in opposition to the lower cutter, to be passed by the lower cutter to thereby cut waste.

8. The waste incineration system according to claim 2, wherein a waste outlet opening and closing plate for opening and closing the waste outlet is installed through the waste feeding drum such that it can be pushed into and pulled out of the waste feeding drum to close and open the waste outlet, and an air injection mechanism is installed between the waste outlet opening and closing plate and the primary incinerator to inject air and thereby form an air curtain in the waste feeding drum.

9. The waste incineration system according to claim 8, wherein a refractory layer is attached to a surface of the waste outlet opening and closing plate.

10. The waste incineration system according to claim 2, wherein the waste pusher comprises: a waste push plate driven by the pusher driving means to push waste into the primary incinerator; and a waste inlet opening and closing plate connected to an upper end of the waste push plate to extend therefrom rearward so that it closes the waste inlet when it is moved forward integrally with the waste push plate.

11. The waste incineration system according to claim 10, wherein a pair of reinforcing plates are connected to both side edges of the waste push plate and the waste inlet opening and closing plate to support the waste inlet opening and closing plate with respect to the waste push plate .

12. The waste incineration system according to claim 2, wherein the pusher driving means comprises a hydraulic cylinder.

13. The waste incineration system according to claim 1, wherein a first combustion air supply chamber is defined below the primary combustion chamber in the primary incinerator to receive air from the air chamber; and each first air nozzle is installed in the bottom wall of the primary combustion chamber such that its injection hole and suction hole are respectively exposed to the primary combustion chamber and the first combustion air supply chamber, to inject air supplied into the first combustion air supply chamber into the primary combustion chamber.

14. The waste incineration system according to claim

1, wherein an embossed portion is formed in the shape of a coil on a side wall of the primary combustion chamber such that a valley portion is also defined on the side wall of the primary combustion chamber due to the presence of the embossed portion.

15. The waste incineration system according to claim 1, wherein an anti-explosion port for reducing a pressure of the primary combustion chamber is defined in the primary incinerator; and anti-explosion port opening and closing means is installed in the anti-explosion port to open the anti- explosion port when a pressure of the primary combustion chamber is greater than a predetermined value and close the anti-explosion port when a pressure of the primary combustion chamber is less than the predetermined value.

16. The waste incineration system according to claim 15, wherein the anti-explosion port opening and closing means comprises a pressure reducing valve.

17. The waste incineration system according to claim 1, wherein a discharge promotion mechanism is installed in an exhaust port of the primary incinerator to inject air in a discharge direction of burnt gas to thereby promote discharge of the burnt gas.

18. The waste incineration system according to claim 1, wherein a second combustion air supply chamber for receiving air from the air chamber is defined in the secondary incinerator around the secondary combustion chamber; and each second air nozzle is installed in the side wall of the secondary combustion chamber such that its injection hole and suction hole are respectively exposed to the secondary combustion chamber and the second combustion air supply chamber, to inject air supplied into the second combustion air supply chamber into the secondary combustion chamber.

19. The waste incineration system according to claim 1, wherein a burnt gas inlet pipe for introducing burnt gas from the water-cooled type heat exchanger into the separation chamber of the cyclone separator is connected to an upper end of the cyclone separator in a tangential direction; and the water pipe is also installed in the burnt gas inlet pipe to extend from the separation chamber toward the burnt gas inlet pipe.

20. The waste incineration system according to claim

19, wherein the water pipe is installed on inner surfaces of the separation chamber and burnt gas inlet pipe to be wound in the shape of a coil.

21. The waste incineration system according to claims 1 or 19, wherein at least one first soot blower is installed at an upper end of the separation chamber to inject steam downward to thereby clean the water pipe.

22. The waste incineration system according to claim

19, wherein the burnt gas inlet pipe is defined at one end thereof with an opening which is to be opened and closed by an opening and closing door; and a second soot blower is installed outside the opening to inject steam through the opening to thereby clean the water pipe installed in the burnt gas inlet pipe.

23. The waste incineration system according to claim

22, wherein the second soot blower is driven by soot blower moving means to be moved into and out of the burnt gas inlet pipe through the opening.

24. The waste incineration system according to claim

23, wherein the soot blower moving means comprises a hydraulic cylinder for reciprocating the second soot blower along a straight path.

25. The waste incineration system according to claim

23, wherein soot blower rotating means is installed between the second soot blower and the soot blower moving means to rotate the second soot blower so that the second soot blower can inject steam in an evenly distributing manner while being rotated about an axis.

26. The waste incineration system according to claim 25, wherein the soot blower rotating means comprises: a rotation plate on which the second soot blower is eccentrically installed; and a rotation plate driving motor installed on the soot blower moving means to rotate the rotation plate.

27. The waste incineration system according to claim

1, wherein an air injection pipe is installed through a wall of the exhaust pipe to inject air supplied from an ejector blower toward an outlet of the exhaust pipe, to thereby facilitate discharge of burnt gas.