BACKGROUND ART Korean Pat. No. 155189 discloses a method of carbonization industrial wastes and apparatus thereof granted to the inventor of the present invention.

Since a hot blast provides indirect and direct heat to the space of the heat- resolving chamber, a large amount of nitrogen, carbon dioxide, carbon monoxide, etc. are contained in the heat-resolved flammable gas. Accordingly, if the impurities are desired to be separated from the heat-resolved flammable gas, excessive costs are required for it.

The inventor develops a resource recovery process that changes wastes into oxygen-free wastes and resolves the oxygen-free wastes into flammable gas and carbon, differently from the conventional burning-up process.

In the present invention, the direct heat is referred to as heat generated while oxygen is supplied to wastes and the wastes are oxidized, while the indirect heat is referred to as heat generated while flammable gas is heat-

resolved and coal powder is burnt.

The indirect heat can be obtained by means of the change of structure by stopping up the heat discharge opening of a fire rod that is means for transmitting direct heat, or by substituting an electric heat rod for the fire rod.

In addition, the indirect heat is obtained by adding pressurized conveying means for controlling air contained the wastes that flow into the space of the heat- resolving chamber of a third step S3.

Furthermore, the indirect heat process is obtained in such a way that coal powder is moved by means of means for passing only carbon between the lower end portion of the third step S3 and the upper end portion of the fourth step S4, coal powder re-powdering and air flow control units 86 and 87 and coal powder crushing units 126 and 127, and air flow is suppressed by means of the movement of coal power by filling the space passage of the third and fourth steps S3 and S4 through a coal storage passage. Since expansion coefficient generated the heat-resolution of the wastes in the heat-resolving chamber by means of indirect heat is increased, a system for controlling the suction force of a fifth step S5 by the measurement of the coefficient and controlling the flammable gas of being sucked to and discharged from the fifth step is operated.

The present invention improves the level of its technology from the conventional burning-up process to an energy extracting and storing process by combining Korean Pat. No. 155189 entitled a method for carbonization-burning industrial wastes and Korean Pat. No. 251891 entitled an auxiliary burning furnace of a burning apparatus with a process for extracting flammable gas.

Of internationally recognized waste burning-up and carbonization processes, the OGADORA carbonization process and the KINSI carbonization process are to input wastes into the interior of a resolving furnace and urge the

heat-resolution of the wastes to be performed by supplying indirect heat from the outside, and the thermo-select carbonization process is to carbonize wastes by heating the outside of pressurizing conveying means. Additionally, the thermo- select process is a process of extracting natural gas by synthesizing pure oxygen and flammable gas while passing the flammable gas through the upper portion of the carbon furnace for burning up carbon. In this process, there is a danger in which toxic oxide such as dioxin may be synthesized.

In the burning-up and carbonization processes, since flammable gas and carbon are burned up in the same burning furnace in a complex manner, an oxidizing action occurs in a furnace and the synthesis of toxic material is performed.

On the other hand, in Korean Pat. No. 155189, since an oxygen-free hot blast is continuously supplied to the wastes, nitrogen, carbon dioxide, carbon monoxide, etc. contained in the direct hot blast flow into a furnace.

Accordingly, since the impurities are mixed with flammable gas, the flammable gas can be burnt up by adding extra energy.

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 method and apparatus for extracting flammable gas from wastes, which does not need an apparatus for separating impurities, such as nitrogen, carbon dioxide, carbon monoxide, etc. from the flammable gas.

The object of the present invention provides is achieved by providing a method of obtaining pure flammable gas in a heat-resolving chamber by

preventing air except for the pure wastes from flowing into the space of the heat- resolving chamber.

In order to achieve the object, the apparatus of the present invention employs a process in which the air contained in the wastes are separated using pressurizing conveying means 104 so as to prevent air from flowing into a heat- resolving furnace of a third step and only pure wastes are input to the heat- resolving furnace, in the process of the wastes flowing into the heat-resolving furnace through first and second steps.

In order to uniformly distribute indirect heat, a plurality of indirect fire conduits are uniformly arranged in the space of the third step, airflow is controlled in the boundary positions B, C and B of third and fourth steps, and air circulation is controlled by means of airflow controls 86 and 87 in the circumferential area of a plate member 85 so as to pass only carbon.

Additionally, a plurality of mills 116,126,127 and 134 are provided to uniformly distribute coal powder. Coal powder storage conduits 90A and 100B are provided to be utilized as intercepting curtains. A system for controlling the suction force of a fifth step S5 by the measurement of the coefficient that is increased due to the generation of flammable gas in a heat-resolving chamber.

Fig. 4 shows"C"and"D"portions of Fig. 1 that serve to move coal powder between the third step and control the fourth step and the movement of air and gas.

The present invention is constructed to allow the total steps of the flammable gas extracting process to be operated individually. The first step S 1 of feeding wastes to the sixth step of conveying and storing ashes are connected to one another through the circulation passages of air. The suction force reaches the space of drying the wastes, the heat-resolving furnace of the third

step S3, the fire plates 37,38 and 39, the upper portion of the fourth step S4, the lower portion of the third step, the first burner, the second gas burner, the third gas burner, the air suction openings 110 and 111 in the form of circulation furnace.

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 taken in conjunction with the accompanying drawings, in which: Fig. 1 is a diagram showing an entire method for extracting flammable gas from waste; Fig. 2 is an enlarged view of"A"portion of Fig. 1 showing an air removing unit and a heat control state; Fig. 3 is an enlarged view of"B"portion of Fig. 1 showing a coal powder discharging apparatus and a gas flow control state; Fig. 4 is an enlarged view of"C"portion of Fig. 1 showing an air suction apparatus and a coal powder flow state; Fig. 5a and 5b is enlarged views of"D"portion of Fig. 1 showing an coal powder re-powdering and air flow control state; Fig. 6 is a diagram showing the flow of heat-resolved material in the apparatus for extracting flammable gas; Fig. 7 is a diagram showing the flow of heat in the apparatus for extracting flammable gas; and Fig. 8 is a diagram showing the flow of flammable gas in the apparatus for extracting flammable gas.

BEST MODES FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention is described with reference to the accompanying drawings, hereinafter.

A flammable gas extracting apparatus of the present invention shown in Figs. 1 to 3 undergoes a first step Sl of initial drying in which fed wastes are initially dried. The apparatus includes means for discharging moisture. Thereafter, the apparatus undergoes a second step S2 of drying and oxygen-free air separation in which the wastes dried in the first step S2 are conveyed by conveying means and dried again and oxygen-free air is separated from the wastes. The apparatus includes a pressurized conveyance means 104 for preventing air from flowing into a heat-resolving chamber of a third step S3 by squeezing air contained the wastes that is being conveyed to undergo the third step S3. A cool water conduit 22 and an agitator 23 are rendered to constitute a heat absorbing unit to change a carbon dioxide gas hot blast 21 greater than 300°C to a dry blast lower than 100°C. The wastes conveyed to the central portion of the heat-resolving furnace is heat-resolved and separated by indirect heat. Heat is continuously accumulated on the wastes. Flammable gas heat- resolved by indirect heat supply means 85,37,38 and 39 is sucked and discharged by a plurality of porous sucking pipes 43. The gas is collected and conveyed by a gas conveying conduit 143. Since the flammable gas and the carbon are discharged from the space of the heat-resolving chamber of the third step, a vacant state is maintained in the interior of the heat-resolving chamber of the third step S3.

The input of the exterior air is minimized through a coal discharge conduit by means of controls 86 and 87, mills 126 and 127, a guide plate 125,

coal powder storage conduits 90 and 100 and bottle neck type coal powder outlets 135 and 136.

The flammable gas is discharged by means of a sucking manifold 43 connected to a second suction unit 55 and carbon is discharged to the fourth step, thereby maintaining the heat-resolving chamber of the third step at a continuous vacant state.

The carbon discharged to the fourth step passes through inner and outer coal powder storage conduits 90A and 100B and the burning furnaces 140 and 141 that fly stored coal powder and completely burn the powder. Heat moved from the burning furnace is indirectly supplied to the heat-resolving furnace.

High temperature oxygen-free exhaustion gas 21 moved from the third step to the second step absorbs heat of high temperature by means of the cooling conduit 22 and the agitator 23 into a dry blast 21 lower than 100°C, is directly supplied to the wastes and dries the wastes. The flammable gas undergoes a pressurizing process of a fifth step. Impurities such as moisture, ashes and tar (including oil) are removed from the flammable gas, thereby producing pure flammable gas. The coal powder is completely burnt in the fourth step.

Ashes produced in the fourth step are collected and conveyed in a sixth step.

In the flammable gas extracting method as described above, the wastes are fed and moisture is removed from the wastes and discharged in the first step, wasted dried and surrounded by oxygen-free air in the second step is input to be fully accumulated in the heat-resolving furnace of the third step S3, the wastes are rapidly heat-resolved into flammable gas and carbon due to rapid heat accumulation by indirect heat transmitting means, the flammable gas is separated by the suction force of the gas purifying chamber of the fifth step S5, and the carbon is discharged to the carbon furnace of the fourth step S4 by the

screw 75 of the top plate of the plate member 85 of the third step S3.

As a result, the heat-resolving chamber of the third step S3 is maintained at a continuous vacant state, and the circulation of the wastes is smoothly performed.

In Fig. 2, a compressing unit 104 for removing air contained in the wastes conveyed from the second step S2 to the third step S3 is illustrated. gas contained in the wastes is squeezed by pressurizing wastes moved from the second step to the third step by means of the pressurizing conveying means 104 including an air discharging outlet 115, a cylinder 95 and a step type conical piston 105 reduced from its front portion to its rear portion, and the flow of air is controlled between the second and third steps.

In Fig. 3, a plate member 85 is mounted between the third step S3 and the fourth step S4. A plurality of fire conduits 38 that are passages for transmitting indirect heat are radially formed. In its center, a fire conduit having a big hole and heat-resolving plate member 85 are formed. A plurality of bi-stage conveying screw 75 are mounted on the one side of the radial fire conduits 38. On the exterior of the conveying screw, coal powder outlet 86, a coal powder control and gas flow control 87 and mill apparatuses 126,127,116 and 134 for re-powdering and uniformly distributing coal powder and controlling the flow of air are placed.

The mill apparatus comprises a rotating upper mill stone 126 disposed between the third and fourth steps, in which a plurality of coal powder storage conduits 128 are formed on the upper inner portion to crush into coal powder and a gear 129-1 is formed in the exterior portion, a power unit consisting of a gear engaged with the gear 129-1 and a motor M driving the gear 129-1, a fixed lower mill stone engaged with and situated under the rotating upper mill stone

126, and a plurality of bearings mounted around the rotating upper mill stone so as to reduce friction by the rotation of the rotating upper mill stone and seal the rotating upper mill stone, a circular ring mounted around the lower portion of the rotating upper mill stone, an outer prop constituting the lower end of the rotating upper mill stone and an inner prop ring for powdering the coal powder, and inner and outer coal powder storage conduits 90 and 100 for distributing.

The coal powder combustion chamber is formed to fully surround the coal powder storage conduits 90A and 100B with the coal powder.

The fourth step S4 of completely burning coal powder shown in Fig. 4 is performed by a coal powder discharge unit 75 radially disposed on the upper plate of the plate member under the third step S3, a coal powder re-powdering unit and air flow controls 86 and 87, a guide plate 125 for guiding coal powder dropped by the mill apparatus 126 and 127 for uniformly distributing coal powder and controlling air flow and the wicker tray 41 having a tilt angle for separating coal powder depending upon its size. A porous distributing plate 41 is formed on its one side. Under the distributing plate 41, there are formed an inner coal powder storage conduit 90A for storing the coal powder of small particles, an outer coal powder storage conduit 100B for storing the coal powder of big particles and air suction openings 110 and 111 positioned under the two coal powder storage conduits A and B. The coal powder discharged from the hopper type coal powder outlets 135 and 136 and air and coal powder entering from air inlets 110 and 111 falls down and are burnt through carbon burning porous member 80 and 81, the top of the combustion chamber is formed as a disc type lid to conduct direct heat, and the direct heat and the conducted heat of the disc lid are transmitted upward through a heat distributing opening 151.

The inner coal powder storage conduit 90A for storing the coal powder

of small particles and the outer coal powder storage conduit 100B for storing the coal powder of big particles that are positioned under the fourth step S4 serves as an intercepting curtain that intercepts the space between the third and fourth steps S3 and S4. The heat transmitting means 150 of the heat-resolving chamber of the fourth step S3 is positioned on the central portion of the fourth step S4 so that a heat distributing opening 151 is utilized as a heat passage, thereby supplying indirect heat to the heat-resolving chamber. The oxygen-free exhaustion gas 21 having passed through the heat-resolving chamber of the third step passes through an exhaustion gas outlet 152 and the conduit 22 and the agitator 23 in the intermediate space ("A"portion of Fig. 1) between the third and second steps into the dry air lower than 100°C, is supplied to the drying chamber of the second step S2, dries the wastes and produces oxygen-free wastes.

Additionally, heat-resolving separation is rapidly achieved by heating the upper plate of the plate member 85 of the third step S3, uniformly distributing the heat of the fourth step to the indirect heat fire plate 38 and 39 and providing indirect heat providing conduit 37 around the outer tank.

In order to extract flammable gas, a plurality of flammable gas sucking pipes are uniformly arranged to extend from the heat-resolving chamber of the third step S3 to the top plate of the plate member 85. The suction force 55 conveys gas to the gas purifying chamber of the fifth step S5. In the heat- resolving chamber of the third step S3 under the step S3 and over the fourth step S4, a first burner 15, the second gas burner 25 and the third gas burner 35 and carbon heat distributing means 151 are positioned. The carbon is changed into coal powder, the coal powder is passed through the wicker tray 41 and fills the inner coal powder storage conduit 90A and the outer coal powder storage

conduit 100B. A plurality of teeth-like through holes are formed on the lower end portion of the coal powder storage conduits 90A and 100B of circular conduit. Air and coal powder flow through the top plate of the combustion plates 80 and 81 and fall down through a plurality of holes and are burnt.

The ashes are positively ionized by the strong electric field by means of an ion generator 61 and are drawn by a negatively charged electric charge needle 62, thereby suppressing the rising of the ashes.

Figs. 5a and 5b show the flow of the wastes in the flammable gas extracting apparatus in the form of circulation in the heat-resolving furnace.

The wastes is dehumidified and dried in the first step, is dried and surrounded by the oxygen-free air in the second step, and is heat-resolved, the flammable gas is drawn by the suction force of the third step and the carbon is discharged to the fourth step in the third step.

Next, the suction force of the first step S 1 reaches the fourth step S4, the third step S3, the indirect heat transmitting means 37, 38 and 39, the first burner 15, the second gas burner 25 and the third gas burner 35 to suck the exterior air. The carbon heat of the fourth step S4 burns the carbon together with sucked air 110 and 111 by means of the suction force of the first step S 1.

The wastes are heat-resolved by means of heat provided in the third step. The wastes are changed to the materials that are suitable for being heat-resolved in the process of passing through the second and first steps.

The present invention allows the total steps of the flammable gas extracting process to be operated individually. That is, the first step S1 of feeding wastes, the second step S2, the third step S3, the fourth step S4 of carbon combustion and the fifth step S5 are performed individually.

Accordingly, the steps are connected to one another by air circulation. The

suction force reaches the space of drying the wastes, the heat-resolving furnace of the third step S3, the fire plates 37,38 and 39, the upper portion of the fourth step S4, the lower portion of the third step, the first burner, the second gas burner, the third gas burner and the air suction openings 110 and 111 in the form of circulation furnace.

The technical problem solved by the present invention is to obtain only flammable gas of high quality among heat-resolved materials. In the third step of extracting flammable gas is required to suppress the input of unnecessary air.

Heat produced in the fourth step is accumulated on the wastes of the third step, thereby achieving rapid heat-resolution. Additionally, oxygen-free exhaustion gas is drawn by the first suction force 11 and dries and surrounds the wastes.

The boiler heat surrounding the circumference of the fourth step serves to dry the wastes of the first step S 1. In addition, the movement of the wastes and the flow of air are formed in opposite orders.

In other words, the wastes moves from the first step to the fourth step in order, while the air exerts the suction force on the drying air of the first step, the first burner, the second gas burner, the third gas burner of the third step and the exterior air inlets 110 and 111 of the carbon combustion unit of the fourth step through the fire plate of the indirect heat providing means. The wastes flowing into the space of the third step S3 is heat-resolved by means of the indirect heat supplied from the indirect heat fire plate 37,38 and 39. The heat-resolved oxygen-free gas is drawn by the suction force of the gas purifying unit of the fifth step and utilized as different energy source.

In order to obtain pure gas among heat-resolved materials, prevent air from flowing into the central portion of the heat-resolution of the third step S3, and prevent air contained in the wastes of the second step S2 from moving to the

heat-resolving chamber of the third step, the wastes are squeezed by the pressurizing conveying means 104 and allows only air-free wastes to pass. The coal powder discharge unit 87, the multiple mills 126,127,134 and 116 for re- powdering coal powder, and the inner coal powder storage conduit 90A and the outer coal powder storage conduit 100B are placed in carbon moving passage between the third step and the fourth step, and bottle neck and hopper type coal powder outlets 135 and 136 for restraining the movement of gas and preventing the sucking force of the fifth step S 5 from reaching the hopper type coal powder outlets 135 and 136 are placed under the two coal powder storage conduits.

This construction is formed to allow the heat-resolving furnace of the third step to connect the second step and the fourth step, thereby allowing the input of the wastes and the discharge of carbon to be achieved and preventing the exterior air from flowing into the space.

Additionally, the sucking unit 55 of the fifth step S5 is constructed to measure the gas expansion coefficient of the heat-resolving furnace of the third step and control the sucking force.

In the present invention, the wastes of the third step is resolved into flammable gas and carbon by means of indirect heat supplied by the heat transmitting means 37,38 and 39, the flammable gas is separated by means of the suction force 55 through a plurality of manifolds 43 extending from the upper portion of the third step to the lower portion of the third step, the carbon is powdered by the screw 75 radially disposed on the top plate of the plate member 85, and the hot blast generated by the combustion of the coal powder is utilized as a heat source for the heat-resolving furnace of the third step. Further, the flammable gas is conveyed to the fifth step, and the conveyed flammable gas is sucked and compressed primarily and is purified by means of the third

pressurizing unit 56 into oxygen-free flammable gas of high quality.

The features of the present invention resides in that the movement of the wastes and the flow of air are performed in opposite directions, and in the process, drying and surrounding are performed by the allotment of rolls.

Additionally, the hot blast moving passages 37,38 and 39 serve to uniformly distribute indirect heat to the wastes.

Furthermore, another feature of the present invention resides in that a high output vibrator 33 and a vibration strip 34 are mounted to outer conduit 31, so that their vibrating force reaches the wastes of the third step, the carbon, the coal powder of the fourth step, coal powder distributing hoppers 135 and 136, the porous plate member 80 and 81 and the circular wicker tray 41 to make movement, distribution and falling movement smooth.

Additionally, in accordance with the present invention, the produced carbon and oxygen-free flammable gas has no danger of explosion due to ignition, and due to the expansion by the heat-resolution of the third step because the space of the heat-resolving furnace is maintained at a continuous vacant state. As a result, since the carbon is burnt at a high temperature greater than 700°C and oxygen-free flammable gas is burnt at a high temperature greater than 1,350°C, toxic oxygen compounds such as dioxin are not synthesized.

INDUSTRIAL APPLICABILITY As described above, the present invention provides a method apparatus for extracting oxygen-free flammable gas from wastes. The present invention provides an oxygen-free flammable gas of a high quality obtained from the wastes as an industrial energy source that can be utilized as energy for thermal-

power generation. In addition, the present invention provides a method of easily heat-resolving industrial wastes, urban wastes, asphalt peat, low quality coal, wood, husks and construction material, thereby obtaining, storing and using oxygen-free flammable gas. In particular, the present invention provides a method of resolving urban wastes and obtaining energy of high capacity.

Therefore, the present invention is useful in waste treatment industry and energy industry.