Abstract:
A small-scale scrapped tire boiler system for heating a small-scale facility using heat generated by burning scrapped tires. The system includes a scrapped tire burner furnace, a heat exchanger for heating a cool heat transfer medium from the facility by the combustion gas from the furnace and supplying the heated medium to the facility, and an exhaust gas purifier for purifying sulfurous acid gas and carbon dust contained in exhaust gas. The purifier includes an exhaust gas tower having a vertical path to discharge the combustion gas, a water sprayer for spraying water from the upper side of the tower so that the sulfurous acid gas is made to melt to water and the carbon dust is made to adsorb to fall down, a neutralizer for precipitating sulfurous acid gas components into alkali salts in a sulfurous acid aqueous solution to thereby neutralize water, and a tank containing the solution and water. The precipitated alkali salts are removed from the bottom of the tank and the floating carbon dust is removed from the upper portion of the tank.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a small-scale boiler system using scrapped tires, and more particularly, to a small-scale scrapped tire fired boiler system in which a high temperature combustion gas generated at the time of incinerating scrapped tires can be used for heating a small-scale facility such as a vinyl plastic hothouse, and the combustion gas can be effectively purified to thereby prevent an air pollution in advance. 
     2. Description of the Related Art 
     As automobile cars increase sharply, scrapped tires also increase in geometrical progression. Meanwhile, a scrapped tire usually consists of eight components having high energy including rubber, carbon, textile and steel. Since the energy included in a scrapped tire is above 8,000 kcal/kg higher than 6,000 kcal/kg which is the amount of heat of coal, the scrapped tire is of very high value as fuel. 
     When a tire is pyrolyzed, middle-classed oil between light oil and hard heavy oil and gas can be extracted at a ratio of five to one. Thus, the scrapped tire has been noted as industrial energy. As a result, various methods and apparatuses have been developed to utilize scrapped tires. 
     For example, scrapped rubber extracted from scrapped tires can be used as a mix when paving a road with asphalt. Also, energy generated at the time of incinerating scrapped tires is collected as a thermal source, to sharply reduce an energy cost. Further, when scrapped tires are pyrolyzed, middle-classed oil between gasoline and light oil is collected and used as fuel for a heat exchanger. At the same time, carbon black is separated from the scrapped tire and recycled at the time of manufacturing tires. 
     Here, when noxious, combustion gas containing sulfurous acid gas, nitrogen carbon monoxide, carbon dust, etc., which is generated at the time of obtaining thermal energy and other extracts from burning scrapped tires is leaked into atmosphere, severe air pollution may be caused. 
     Therefore, to prevent the air pollution, the combustion gas generated during burning the scrapped tires should be refired for perfect combustion. Otherwise, sulfurous acid gas (SO 2 ) is made to react to water (H 2 O), to separate the sulfurous acid gas (SO 2 ) from the combustion gas, and to then be discharged in the air, using the characteristic that the former melts well by the latter. 
     However, in the case of the above wet removal method, combustion gas should pass through a large-scale charging material layer in order to make the combustion gas generated in a burning furnace react well to water. Thus, since it is not easy to develop a small-scale wet apparatus, the wet removal method has not been appropriate for a small-scale heating. 
     Also, a dry removal method using adsorption of a solid state of noxious gas requires a facility such as a very expensive air purifier. Thus, the dry removal method has not been developed for small-scale equipment. 
     SUMMARY OF THE INVENTION 
     To solve the above problems, it is an object of the present invention to provide a small-scale boiler system having an exhaust gas purifier which can effectively purify sulfurous acid gas, carbon dust, etc., contained in combustion gas (exhaust gas) when high temperature combustion gas generated by burning scrapped tires is applied to a small-scale heating. 
     It is another object of the present invention to provide a small-scale boiler system which quickly performs perfect combustion of nitrogen carbon monoxide which is increasingly generated at the last stage of the combustion, to then reduce an amount of discharged nitrogen carbon monoxide and shorten an ash processing period. 
     To accomplish the above object of the present invention, there is provided a small-scale scrapped tire boiler system for heating a small-scale facility to be heated using heat generated during burning scrapped tires, the small-scale boiler system comprising: a scrapped tire burner furnace for burning the scrapped tires and producing high-temperature combustion gas; a heat exchanger for heating a heat transfer medium by the high-temperature combustion gas generated in the burner to perform heat exchange with the cooled heat transfer medium fed back from the facility to be heated and supplying the heated heat transfer medium to the facility to be heated; and an exhaust gas purifier for purifying sulfurous acid gas and carbon dust contained in exhaust gas discharged in the air via the heat exchanger. 
     It is preferable that the exhaust gas purifier comprises: an exhaust gas tower having a vertical path to discharge the combustion gas having passed through the heat exchanger; a water sprayer for spraying water from the upper side of the exhaust gas tower in such a manner that the sulfurous acid gas contained in the discharged combustion gas is made to melt to water and the carbon dust is made to adsorb to fall down; and a neutralizer for precipitating sulfurous acid gas components into alkali salts in a sulfurous acid aqueous solution where the sulfurous acid gas is dissolved to thereby neutralize water. 
     It is also preferable that the exhaust gas purifier comprises: an exhaust gas tower having a vertical path to discharge the combustion gas having passed through the heat exchanger; a water tank communicating with the bottom side of the exhaust gas tower and containing a certain amount of purifying water; a water sprayer for circulating the purifying water and spraying water from the upper side of the exhaust gas tower; a reaction accelerator disposed at the upper side of the exhaust gas tower, lengthening a reaction time between the combustion gas and the water in such a manner that sufficient time and contact area are kept so that the sulfurous acid gas contained in the discharged combustion gas is made to be dissolved to the sprayed water; and a limestone charging layer for precipitating the sulfurous acid produced from the sulfurous acid gas dissolved while having passed through the reaction accelerator into gypsum. 
     According to the present invention, the burner furnace comprises: a housing forming a combustion chamber in which scrapped tires are loaded; a first light oil inlet disposed in the upper portion of the combustion chamber, for injecting a combustible material; an air heating induction pipe disposed in the inner circumferential surface of the housing; a burner disposed in a connection path connected with a heat exchanger; and a return means for returning the air heated by the burner to the combustion chamber. 
     It is also preferable that the burner furnace further comprises a second injection inlet disposed in the lower portion of the combustion chamber, for injecting a combustible material, and a fan for injecting the input combustible material into the inside of the combustion chamber together with the external air. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The objects and other advantages of the present invention will become more apparent by describing in detail the structures and operations of the present invention with reference to the accompanying drawings, in which: 
     FIG. 1 is a schematic perspective view showing a scrapped tire boiler system according to the present invention; 
     FIG. 2 is a sectional view showing the internal structure of the scrapped tire boiler system shown in FIG. 1; 
     FIG. 3 is an enlarged perspective view showing an example of a charging unit to be used in an exhaust gas purifier; 
     FIG. 4 is a graphical view showing the change of the pH values of a combustion gas G 1  before passing through the charging units and a combustion gas G 2  after having passed through the charging units, according to time, in the exhaust gas purifier; 
     FIG. 5 is a schematic sectional view of a water tank having a sulfurous acid reaction accelerating structure using a rotary stirrer in the exhaust gas purifier; 
     FIG. 6 is a schematic sectional view of a water tank having a sulfurous acid reaction accelerating structure using a chemical material in the exhaust gas purifier; 
     FIG. 7 is a graphical view showing the change of the pH values according to time in the cases that the sulfurous acid reaction accelerating structure has been employed or not employed; 
     FIG. 8 is a sectional view showing a detailed structure of the scrapped tire burner furnace shown in FIG. 1; and 
     FIG. 9 is a graphical view showing an amount of nitrogen carbon monoxide generated in the cases of a general burner furnace and the present invention burner furnace. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     Referring to FIGS. 1 and 2, a scrapped tire boiler system includes a burner furnace  10  for burning scrapped tires  15  and producing high-temperature combustion gas  100 , a heat exchanger  20  for heating an internal cooled water by the high-temperature combustion gas  100 , and an exhaust gas purifier  30  for removing a pollutant contained in the combustion gas  100  heat-exchanged in the heat exchanger  20  and discharging an exhaust gas in the air. The warm or hot water heat-exchanged in the heat exchanger  20  circulates a heating pipe  41  of a facility to be heated such as a gardening facility house or a vinyl plastic hot house  40  to perform a heat exchange, in which a supply pipe  21  and a return pipe  23  are connected to the heat exchanger  20 . 
     Referring to FIG. 2, the structure of the scrapped tire burning apparatus will be described below in more detail. First, the burner furnace  10  is provided with a charging inlet  13  for putting scrapped tires therein, a spacing chamber  10   a  for charging the scrapped tires therein, and a burner  11  for heating the scrapped tires  15  on the bottom side thereof. 
     In order to transfer a high-temperature and high-pressure combustion gas  100  generated during burning the scrapped tires  15  to a heating pipe  25  in the heat exchanger  20 , a first gas transfer pipe  17  is connected between the upper side of the burner furnace  10  and one end of the heating pipe  25  installed in the heat exchanger  20 . A second gas transfer pipe  19  is connected between the other end of the heating pipe  25  and the central portion of an exhaust gas tower  31 . A blower BI is installed in somewhere along the second gas transfer pipe  19  in order to smoothly transfer and discharge the combustion gas  100 . 
     Meanwhile, the heating pipe  25  in the heat exchanger  20  is heated by the passage of the high-temperature combustion gas  100 . Accordingly, cool water charged in the heat exchanger  20  is changed into warm water. Also, in order to transfer the warm water heated in the heat exchanger to the heating pipe  41  in a vinyl plastic hothouse, the supply pipe  21  communicates between the upper side of the heat exchanger  20  and one end of the heating pipe  41  of the vinyl plastic hothouse  40 . Also, in order to recirculate the cooled water which has been heat-exchanged via the heating pipe  41  to the heat exchanger  20 , the return pipe  23  communicates between the other end of the heating pipe  41  and the bottom side of the heat exchanger  20 . A circulation pump P 1  is installed in somewhere along the return pipe  23  in order to effectively circulate the recirculated water between the heating pipe  41  of the vinyl plastic hothouse  40  and the heat exchanger  20 . 
     Meanwhile, the exhaust gas purifier  30  includes the exhaust gas tower  31 . A plurality of charging units  50  of approximately 4 meters high are installed in the inner central portion of the exhaust gas tower  31 , in order to increase a contact area and time between the combustion gas  100  input via the second gas transfer pipe  19  and the water  80 . It is preferable that the second gas transfer pipe  19  is positioned to communicate with the bottom side of the charging units  50  so that a contact time between the combustion gas  100  input into the charging units  50  and the plurality of charging units  50  is lengthened. Also, a limestone charging layer  60  for removing sulphuric components S of the sulfurous acid gas (SO 2 ) by precipitation is disposed on the bottom side of the charging units  50 , so that the limestone charging layer  60  is spaced by a predetermined distance from a water tank  33  communicating with the bottom side of the exhaust gas tower  31 . 
     Meanwhile, a water spraying pipe  35  protrudes to spray water downwards from the upper side of the exhaust gas tower  31 , that is, toward the charging units  50 . Also, the other end of the water spraying pipe  35  extends to communicate with the central portion of the water tank  33 . A circulation pipe P 2  for recirculating water  80  charged to the water tank  33  into the inside of the exhaust gas tower  31  via the water spraying pipe  35  is disposed in the lower side of the water spraying pipe  35 . 
     Each of the plurality of charging units  50  filled in the exhaust gas tower  31  is made of a cylindrical vessel  51  having a plurality of contact opening pieces  52  formed on the lateral surface of the cylindrical vessel  51  and made of a solid fire-resistant material, in order to lengthen a contact time between the combustion gas  100  and the water  80  sprayed from the upper side of the charging units  50  during discharging the combustion gas  100  via a chimney  37  of the exhaust gas tower  31 , that is, in order to increase a contact area, e.g., between the combustion gas  100  and the water  80  as shown in FIG.  3 . 
     It is also possible to form the charging units  50  to have a rectangular shape or a polygonal shape. It is also possible to use a fire-resistant plastic, ceramic, or a gravel, for example, a fire-resistant material having a certain shape as a material of the charging units  50 . 
     Meanwhile, on the upper portion of the water tank  33  is formed a first discharging outlet  33   a  having a predetermined diameter in order to remove carbon dust floating on the upper side of the water. On the lower portion of the water tank  33  is formed a second discharging outlet  33   b  in order to remove gypsum sunk in the purifying water. 
     The effect and function of the present invention as constructed above will be described below in more detail. 
     First, a plurality of scrapped tires on the whole or in pieces are charged into the spacing  10   a  of the burning furnace  10 , via the charging inlet  13  of the burning furnace  10 , and then the burner  11  is turned on to operate to heat the scrapped tires  15 . 
     Accordingly, the scrapped tires are burnt to generate a high-temperature and high-pressure combustion gas  100 . The combustion gas  100  passes through the first gas transfer pipe  17  and then passes through a wrinkled heating pipe  25  in the heat exchanger  20 . 
     The water  27  charged in the inside of the heat exchanger  20  is heated by the heating pipe  25  so that the temperature rises up to a predetermined temperature. The temperature-risen water, that is, warm water passes through the supply pipe  21  according to operation of the circulation pump P 1 , to move along the heating pipe  41  installed under and/or on the ground of the vinyl plastic hothouse  40 , and to heat the air under and/or on the ground of the vinyl plastic hothouse  40 . 
     Thereafter, the warm water having passed through the low-temperature underground or ground heating pipe  41  falls down in temperature, and circulates to the heat exchanger  20  via the return pipe  23  by the circulation pump P 1 . In this case, it is possible to regulate the temperature of the vinyl plastic hothouse  40  by setting an operation time of the circulation pump P 1 . 
     Meanwhile, the combustion gas  100  whose temperature has been lowered via a heat-exchange process in the heating pipe  25  is transferred to the exhaust gas tower  31  of the exhaust gas purifier  30  along the second gas transfer pipe  19  by the blower B 1 , and then smeared from the bottom side rising up to the upper side in the charging units  50 . The combustion gas  100  sufficiently contacts to water sprayed from the water spraying pipe  35  when the combustion gas  100  rises up via the plurality of charging units  50 . At this time, the sulfurous acid gas (SO 2 ) contained in the combustion gas  100  is dissolved in the water. Then, the water in which the sulfurous acid gas (SO 2 ) has been dissolved passes through a limestone CaCO 3  in the limestone charging layer  60  and flows downwards. 
     Then, the sulfurous acid gas (SO 2 ) dissolved in the water H 2 O passes through the limestone  60   a  and reacts with the limestone  60   a  to form gypsum  90  CaSO 4 . Since the gypsum from which humidity is not removed is soluble to a degree, it is charged into the water tank  33  formed in communication with the lower side of the exhaust gas tower  31 . In this case, part of the gypsum CaSO 4  clings to the surface of the limestone CaCO 3  according to lapse of time. Thus, when the purifier is used for a long time, a reaction capability of the sulfurous acid SO 2 . H 2 O remarkably deteriorates by the gypsum coated on the surface of the limestone. Thus, a countermeasure for preventing a reaction capability from lowering while keeping a small-scale boiler system is needed. 
     For this purpose, it is crucial that the gypsum CaSO 4  is consistently removed from the surface of the limestone  60   a  by a proper water pressure prior to being dried. It is also important that the flow of the water is kept at the state where the limestone  60   a  is not exposed in the air from the water charged in the water tank  33 . 
     Meanwhile, the purifying water  80  from which acidity has been removed by reaction with the limestone is sprayed via spraying holes  35   a  of the water spray pipe  35  by the circulation pump P 2  connected on the bottom side of the water spray pipe  35 , and is circulated in the exhaust gas tower  31 . 
     At the same time, the carbon dust  70  contained in the combustion gas  100  flows into the water tank  33  by the water sprayed in the water spray pipe  35  and floats on the water  80  charged in the water tank  33 . Thus, the carbon dust  70  floating on the water is collected via the first discharging outlet  33   a  installed in the level similar to the water level at an appropriate time, and the gypsum CaSO 4  sunk on the bottom surface of the water tank  33  is removed via the second discharging outlet  33   b  at an appropriate time. 
     As described above, the combustion gas  100  purified during the above repetitive process is discharged in the air via the chimney  37  of the exhaust gas tower  31 . 
     Meanwhile, the structure for solving the phenomenon that a reaction capability with the sulfurous acid SO 2 . H 2 O due to the gypsum coated on the surface of the limestone is shown in FIG.  5 . As depicted, a rotary stirrer  200  is inserted and rotated into the purifying water in the water tank  430 , in which a limestone  60   a  is charged in the inside of the rotary stirrer  200 . In this case, gypsum CaSO 4  coated on the surface of the limestone  60   a  is removed according to lapse of time. 
     Alternatively, a method for dissolving gypsum is shown in FIG.  6 . As shown, a chemical transfer pipe  350  is installed in one side of the water tank  530 . A plurality of partition walls  300  of which one end is fixed in the inside of the water tank  530  alternately up and down are formed in the water tank  530 . A predetermined limestone  60   a  is charged between the partition walls  300 . In this case, hydrogen peroxide H 2 O 2  is added in the water tank  530  as a solvent for dissolving the gypsum. 
     Also, in the inner lower portion of the water tank  530  is formed a screen filter  330  for separating gypsum in order to precipitate the gypsum produced after the sulfurous acid aqueous solution has reacted with the limestone on the bottom floor of the water tank. On the bottom surface of the water tank are formed a plurality of gypsum removal holes  310  for removing the gypsum and precipitant. Thus, the purified water while passing through the inside of the water tank is circulated into the water spray pipe  35  in the exhaust gas tower  31 . 
     FIG. 7 is a graphical view showing the measured results of the pH values according to reaction time in the cases that A 1 ) the limestone is stirred, A 2 ) the hydrogen peroxide is added in the sulfurous acid gas aqueous solution, and A 3 ) the limestone is not stirred. As shown in these graphs, a reaction velocity in the case A 3  that the limestone is not stirred is remarkably lowered compared with the case A 1  that the limestone is stirred. In the case A 2  that the hydrogen peroxide is added in the water tank, an efficient chemical reaction can be obtained without a mechanical stirring operation. 
     Meanwhile, scrapped tires of 500 Kg are charged into the burner furnace  10  to heat them for 15 hours in order to test a sulfurous acid gas removal capability of the exhaust gas purifying apparatus  30  and a reduction reaction result of the limestone according to lapse of time. At this time, it can be seen from FIG. 4 that the changes of the pH value with respect to the combustion gas G 1  taken before passing through the charging units  50 , that is, from the lowest portion of the charging units  50 , and the combustion gas G 2  after passing through the charging units  50 , that is, taken from the upper portion of the charging units  50  differ from each other remarkably. That is, the combustion gas G 1  before passing through the charging units appears as a strong acidity, and the combustion gas G 2  after having passed through the charging units appears as a weak acidity. It can be seen that the sulfurous acid gas (SO 2 ) can be effectively removed from the exhaust gas having passed through the exhaust gas purifying apparatus  30 . 
     Also, the pH value of the combustion gas becomes a strong acidity as combustion reaches the last stage of combustion. Since combustion gas is not generated any more if combustion finishes, the pH value of the combustion gases G 1  and G 2  are same. 
     In the present invention, the content of the sulfurous acid gas in the combustion gas discharged in the air is detected lower than an environmental standard reference value of 800 ppm. Also, it can be seen that the carbon dust has been almost removed. 
     Meanwhile, when the scrapped tires are burnt, the fuel gas is extracted by rubber components in the scrapped tires to generate a large amount of sulfurous acid gases. However, in the last stage when the rubber components are dried by distillation and thus the fuel gas is not extracted any more, that is, in the ash processing period for the last three to five hours, the scrapped tires&#39; ashes remain and thus the content of the sulfurous acid gases in the combustion gas is sharply reduced. However, the content of the hydrogen carbon monoxide is increased in geometrical progression referring to FIG.  9 . 
     In the above ash processing period, it is not possible to extract the fuel gas, and thus heating power cannot be supplied to the boiler system. In this case, since the hydrogen carbon monoxide being a pollutant is discharged in the exhaust gas, the shorter ash processing period the better. It is not possible to remove the hydrogen carbon monoxide by the wet purifying method, differently from the sulfurous acid gas. Also, the concentration of the hydrogen carbon monoxide is high and the discharge time thereof is long. 
     FIG. 8 shows a scrapped tire burner furnace which can reduce a discharge time and discharge amount of the hydrogen carbon monoxide. 
     The burner furnace  10  according to the present invention is comprised of a housing  1  forming a combustion chamber  10   a  in which scrapped tires  15  are charged, a first light oil inlet  2  disposed in the upper portion of the combustion chamber  10   a , for injecting a combustible material, for example, light oil, an air heating induction pipe  4  disposed in the inner circumferential surface of the housing, a burner  5  disposed in a first gas transfer pipe  17  connected with a heat exchanger  20 , a return fan  6  for returning the air heated by the burner  5  to the combustion chamber  10   a , and a return pipe  7 . 
     Also, the burner furnace  10  further includes a second light oil inlet  3  disposed in the lower portion of the combustion chamber  10   a  and a fan  8  for injecting the input light oil into the combustion chamber  10   a  together with the cool air. 
     In the above burner furnace  10 , the rubber components in the charged scrapped tires  15  are all burnt. Thus, if light oil is injected at the time when the fuel gas supplied from the burner furnace  10  to the heat exchanger  20  is interrupted, the housing  1  of the burner furnace  10  and the first gas transfer pipe  17  have been already heated up to a high temperature. Accordingly, the light oil vaporizes. The vaporized light oil is transferred toward the heat exchanger  20  together with the hydrogen carbon monoxide generated during imperfect combustion. 
     At this time, if the burner  9  positioned in the inlet side of the heat exchanger, that is, the first gas transfer pipe  17  is ignited, the light oil vapor is ignited, and thus the hydrogen carbon monoxide is oxidized into hydrogen carbon dioxide. Thus, there is no hydrogen carbon monoxide in the exhaust gas. As described above, when light oil is injected in the processing of the ash, the injection amount of cool air can be increased to thereby largely shorten the ash processing period. 
     By experiment, the ash processing time which is taken five hours or so in the case that the scrapped tires of 500 Kg are charged can be shortened less than one hour by injecting light oil. As the air inlet amount increases, the light oil vapor is diluted. Accordingly, the combustion state of the burner  5  gets worse and the content of the hydrogen carbon monoxide increases in the exhaust gas. Also, since the ash processing period is lengthened if the air inlet amount becomes smaller, the amount of the light oil needed in the ash processing period increases. Thus, it is preferable that the air inlet amount and the light oil injection amount are optimized according to the scale of the apparatus. 
     In the case of injection of the light oil, the light oil can be injected via the second light oil inlet  3  together with cool air, or can be injected over the ash via the first light oil inlet  2  irrespective of the cool air. By the experimental results, the case that light oil is injected over the ash via the first light oil inlet  2  can save the amount of light oil needed for the ash processing, when compared with the case that the light oil is injected together with cool air from the bottom via the second light oil inlet  3  by the fan  8 , which is however not effective for removal of the hydrogen carbon monoxide. 
     Meanwhile, in the case that warm air produced by the burner  5  is made to return to the combustion chamber  10   a  via the return pipe  7  by operation of the fan  6 , instead of the cool air, the thermal efficiency of the boiler  70  is enhanced and the ash processing time and the amount of the light oil needed for the ash processing can be effectively reduced. In each case, the change of time with respect to the amount of the hydrogen carbon monoxide generated is shown in FIG.  9 . 
     In the above embodiment, the height of the charging material layer in the exhaust gas tower  31  is made to be  4  meters or so, to be adapted for a small-scale heating boiler system. However, as the structure of the charging units  50  is optimally made to have an exhaust gas to be smoothly discharged and the contact time of the water is lengthened and the height of the exhaust gas tower  30  is increased, it is possible to furthermore enhance a capability of removing a pollutant. Also, as the burner furnace  10 , the heat exchanger  20  and the exhaust gas purifying apparatus  30  are enlarged in scale, it is possible to use the present invention as an industrial medium-sized boiler system. 
     Therefore, although the scrapped tires require a facility investment such as an expensive air purifier for processing the sulfurous acid gas and the carbon dust, the present invention can use cheap scrapped tires as a fuel resource and secure the thermal source of the heat exchanger. Also, the present invention can prevent an air pollution due to the pollutant. The heat exchanger is appropriate for heating of a small-scale area of 15,000 m 2  or so, in particular, for heating a gardening vinyl plastic hothouse. In view of the size of the apparatus, the size of the exhaust gas tower is minimized by using the charging units material of the appropriate shape. 
     In addition, the water circulated in the water tank which is obtained as a by-product in the purifier according to the present invention can be used for preventing or curing powdery mildew fatal to roses. The finite carbon powder is mixed with a plastic material for home appliances to be used for generating a color. The gypsum also can be used as a multiple purpose. The present invention can solve the environmental problem and enable the application of the by-product. 
     Thus, the boiler system according to the present invention can be effectively applied to a small-scale heating apparatus such as a vinyl plastic hothouse using cheap scrapped tires as fuel without discharging pollutants. 
     As described above, the present invention has been described as particularly preferred embodiments. However, the present invention is not limited in the above embodiments and various modifications and changes are possible by one skilled in the art within the scope without departing from the spirit of the present invention.