Abstract:
A gasifying apparatus including a variable gasifier and used as both a power generator and a combustion boiler and a method of driving the same are disclosed. A combustion boiler and a generator engine, driven with synthesis gas, are associated with a single gasifier, and the gasifying apparatus produces synthesis gas proper to a technical field of the gasifier by selectively applying an upflow gasifier and a downflow gasifier according to the technical field of the gasifier.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from Korean patent application no. 10-2012-0068800 filed Jun. 26, 2012, all of which is incorporated herein by reference in its entirety for all purposes. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a gasifying apparatus including a variable gasifier and used as both a power generator and a combustion boiler and a method of driving the same, and more particularly to a gasifying apparatus in which a combustion boiler and a generator engine, driven with synthesis gas, are associated with a single gasifier, and for producing synthesis gas proper to a technical field of the gasifier by selectively applying an upflow gasifier and a downflow gasifier according to the technical field of the gasifier. 
         [0004]    2. Description of the Prior Art 
         [0005]    Gasification is a technology that produces synthesis gas containing carbon monoxide (CO) and hydrogen (H 2 ) from carbon in fuel consisting of hydrocarbons through an endothermic reaction of carbon using partial oxidation heat, carbon dioxide (CO 2 ), and water (H 2 O). 
         [0006]    Various gasifying apparatuses, to which the gasification technology is applied, are developed to be suitable for various fuels, oxidants, and purposes thereof. 
         [0007]    If air and water vapor are used as gasifying agents in a fixed bed gasifier employed in a small-sized system, low calorie gas of 1,000 kcal/Nm 3  to 2,000 kcal/Nm 3  may be produced. 
         [0008]    In general, a downflow-type fixed bed gasifying apparatus is used to generate distributed power for the purpose of reducing produced tar. 
         [0009]    However, since the downflow-type gasifying apparatus has slightly difficult starting-up conditions, the easily operable upflow-type gasifying apparatus is recommended for use when the product synthesis gas is burnt itself or with oil. 
         [0010]    That is, the upflow-type gasifier has merits in higher thermal efficiency, easier control, and higher compatibility of fuel conversion than the downflow-type gasifier, but has also drawbacks such as high quantity of product tar, high costs for filtering the synthesis gas, and most of all, removal of the tar from the product synthesis gas. 
         [0011]    Meanwhile, the downflow-type gasifier may produce synthesis gas containing less tar and grains, but can sustain a stable process only when moisture is 20% or less within in a fuel. 
         [0012]    Most enterprises and facility farms have different seasons of demanding electric power and using heat. Thus, since gasifiers, which use electric power or heat respectively, must be used to generate electric power or to burn synthesis gas by using synthesis gases produced through the gasifiers, facility costs increase. 
       SUMMARY OF THE INVENTION 
       [0013]    Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a gasifying apparatus with a variable gasifier using a power generator and combustion boiler and a method of driving the same such that a proper quality of synthesis gas, produced by selectively applying upflow gasifcation or downflow gasification with a single gasifier, is supplied to be suitable for the purpose. 
         [0014]    In order to accomplish this object, there is provided a gasifying apparatus with a variable gasifier using a power generator and combustion boiler, including: a variable gasifier varied such that fuel such as coal, biomass, RDF, and RPF is fed to perform upflow gasification or downflow gasification; a filtration device filtering synthesis gas produced by the variable gasifier; a feed controller controlling feeding direction of the synthesis gas filtered by the filtration device; and a combustion boiler and a gas engine driven with the synthesis gas selectively fed by the feed controller. 
         [0015]    The gasifier includes: an introduction chamber having a fuel feeder formed at a top through which fuel is introduced; a gasification chamber positioned under the introduction chamber and a rotary grate formed on the bottom thereof to accumulate the fuel such that gasification is performed and to discharge ash after combustion is completed through the lower side; an outer chamber enclosing the gasification chamber, separated from the introduction chamber by a partition, and having an ash discharging hole formed on the bottom; a first gasification agent injection hole inserted into the outer chamber to communicate with the gasification chamber and inject gasification agent during the downflow gasification; a second gasification agent injection hole communicating to the lower side of the outer chamber and injecting the gasification agent during the upflow gasification; and a passage opening/closing unit including three directional passages as discharging apertures through which the synthesis gas is discharged from a side of the partition to the introduction chamber, the outer chamber, and the outside, communicating to the outer chamber with the synthesis gas discharging hole during the downflow gasification and communicating to the introduction chamber with the synthesis gas discharging hole during the upflow gasification for the discharge of the synthesis gas. 
         [0016]    In accordance with another aspect of the present invention, there is provided a method of driving the gasifying apparatus including the steps of: introducing fuel through a fuel feeder to be accumulated in a gasification chamber of a gasifier while blocking oxygen from being introduced; determining whether the synthesis gas, which is produced by gasifying the fed fuel, is used for power generation or for a combustion boiler; communicating a synthesis gas discharging hole of a passage opening/closing unit with the introduction chamber or the outer chamber according to the determination; performing upflow gasification or downflow gasification by feeding gasification agent through a first or a second gasification agent injection hole according to the determination; producing the synthesis gas by performing the upflow gasification or the downflow gasification according to the performance of the upflow gasification or the downflow gasification; filtering foreign matter contained in the product synthesis gas; and generating electric power by feeding the synthesis gas filtered in the filtration into the gas engine or recovering heat by feeding the filtered synthesis gas into the combustion boiler. 
         [0017]    According to the gasifying apparatus with a variable gasifier using a power generator and combustion boiler and a method of driving the same in accordance with the present invention, the gasifying apparatus further includes a passage opening/closing unit provided in the front side of a synthesis gas discharging hole to selectively communicate an upper space and a lower space in the gasifier partitioned by the gasification chamber and to change an injection position of the gasification agent such that upflow gasification and downflow gasification can be selectively performed. 
         [0018]    Especially, when the synthesis gas is used for generating electric power or the combustion boiler, gasification suitable for the purpose is performed such that the synthesis gas is produced and fed so that unnecessary filtration can be omitted and thermal efficiency can be improved. Therefore, easy control can be achieved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0020]      FIG. 1  is a schematic view illustrating a gasifying apparatus for generating electric power and providing heat using a variable gasifier according to an embodiment of the present invention; 
           [0021]      FIG. 2  is a schematic sectional view illustrating a gasifier according to an embodiment of the present invention; 
           [0022]      FIGS. 3A ,  3 B, and  3 C are schematic sectional views illustrating a passage opening/closing unit according to an embodiment of the present invention; 
           [0023]      FIGS. 4 and 5  are schematic sectional views illustrating a gasifying agent inflow adjustor of a first gasifying agent injection hole according to an embodiment of the present invention; 
           [0024]      FIG. 6  is a block diagram illustrating a method of driving a gasifying apparatus according to an embodiment of the present invention; 
           [0025]      FIGS. 7 and 8  are schematic views illustrating driving in which upflow gasification and downflow gasification are carried out in the gasifier according to the embodiment of the present invention; 
           [0026]      FIGS. 9 and 10  are graphs illustrating components of synthesis gas produced during the upflow driving and the downflow driving of the gasifier according to the embodiment of the present invention; and 
           [0027]      FIG. 11  is a schematic view illustrating a measuring device collecting tar contained in the synthesis gas produced in the gasifier according to the embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following description and drawings, the same reference numerals are used to designate the same or similar components, and so repetition of the description on the same or similar components will be omitted. 
         [0029]      FIG. 1  is a schematic view illustrating a gasifying apparatus for generating electric power and providing heat using a variable gasifier according to an embodiment of the present invention. 
         [0030]    As illustrated, a gasifying apparatus  1  according to an embodiment of the present invention includes a variable gasifier  10  varying such that fuel such as coal, biomass, RDF, and RPF is fed to perform upflow gasification or downflow gasification, a filtration device  20  filtering synthesis gas produced by the variable gasifier  10 , a feed controller  30  controlling feeding direction of the synthesis gas filtered by the filtration device  20 , and a combustion boiler  40  and a gas engine  50  driven with the synthesis gas selectively fed by the feed controller  30 . 
         [0031]    The gasifying apparatus  1  is configured to selectively enable upflow gasification and downflow gasification using a single gasifier such that synthesis gas is produced through downflow gasification, driving conditions of which are complicated when synthesis gas with low foreign matter content such as tar is used to drive a gas engine while such that the synthesis gas is produced through upflow gasification easily driven when the synthesis gas is fed to a combustion boiler burning the synthesis gas as a fuel regardless of the content of tar. 
         [0032]      FIG. 2  is a schematic sectional view illustrating a gasifier according to an embodiment of the present invention. 
         [0033]    As illustrated, the gasifier  10  of the present invention is a vertical type in which an introduction chamber  11 , a gasification chamber  12 , and an outer chamber  13  are sequentially installed from top to bottom, wherein the outer chamber  13  encloses the gasification chamber  12  so that the outer chamber  13  communicates with the introduction chamber  11  via the gasification chamber  12 . 
         [0034]    The introduction chamber  11  is provided with a fuel feeder  111  on top. The fuel feeder  111  is configured such that two layer gate valves (slide gates)  113  are installed under a hopper  112  serving as a fuel supplying unit to be sequentially opened such that fuel only is introduced therein and air is prevented from being introduced therein. 
         [0035]    The gasification chamber  12  has an upper side communicating with the introduction chamber  11  and a lower side communicating with the outer chamber  13  and includes a porous plate, that is, a grate  121  installed at the lower side to discharge ash which is already burnt or gasified. The grate  121  may be a circular plate in which a plurality of pins protrude from the upper side thereof or in which has multi-layer thin circular plates, and includes a rotary shaft, rotated by a driving force, coupled to the lower side to scrape ash accumulated on the gasification chamber  12  during the rotation to be easily discharged. 
         [0036]    Next, the outer chamber  13  encloses the gasification chamber  12  and has upper sides divided by the introduction chamber  11  and a partition  17 . The outer chamber  13  is provided with an ash discharging hole  131  formed at the lower side to collect and discharge the ash discharged from the gasification chamber  12 . In this case, the ash discharging hole  131  includes a collector  132  and a screw conveyor  133  such that the ash discharged from the ash discharging hole  131  can be continuously discharged out of the gasifying apparatus  1 , wherein the screw conveyor  133  has an upward slope from the collector  132  such that the ash and a screw block a passage to prevent gas from being discharged through the ash discharging hole  131  from the outer chamber  13 . 
         [0037]    As described above, the gasifier  10  including the introduction chamber  11 , the gasification chamber  12 , and the outer chamber  13  further includes a first gasification agent injection hole  14  and a second gasification agent injection hole  15  to feed a gasification agent consisting of air or a mixture of air and water vapor. The first gasification agent injection hole  14  communicates with the gasification chamber  12  by penetrating the outer chamber  13  such that the gasification agent is injected during the downflow gasification, while the second gasification agent injection hole  15  communicates with the lower side of the outer chamber  13  such that the gasification agent is injected during the upflow gasification. 
         [0038]    Valves are mounted on lines of the first and second gasification agent injection holes  14  and  15  such that the gasification agent may be selectively injected. For the upflow gasification in the gasification chamber  12 , the gasification agent may be fed through the second gasification agent injection hole  15  and a forced draft fan (FD fan)  70  may be installed at a front line of the second gasification agent injection hole  15  such that forced blowing toward the gasification chamber  12  can be carried out. For the downflow gasification, an induced draft fan (ID fan)  60  is installed at a rear line connected to a later-described synthesis gas discharging hole  163  such that blowing is carried out by suctioning by the gasifier  10 , resulting in a fluid stream throughout the gasifying apparatus  1 . 
         [0039]    A passage opening/closing unit  16  is installed at a side of the partition  17  partitioning the upper side of the outer chamber  13  enclosing the gasification chamber  12  and the lower side of the introduction chamber  11 . The passage opening/closing unit  16  has three directional passages such as a synthesis gas discharging hole  163  communicated with the outside of the gasifier  10 , a passage  164  communicated with the introduction chamber  11 , and a passage  165  communicated with the outer chamber  13  and closes any one of the two passages  164  and  165  that are communicated with the introduction chamber  11  and the outer chamber  13  such that only one of the two passages  164  and  165  communicated with the introduction chamber  11  and the outer chamber  13  the synthesis gas communicates with the synthesis gas discharging hole  163  to discharge the synthesis gas. 
         [0040]    As illustrated in  FIGS. 3A and 3B , the passage opening/closing unit  16  may include an opening/closing chamber  161  elongated horizontally and an opening/closing piston  162  inserted into the opening/closing chamber  161 . 
         [0041]    The opening/closing chamber  161  may be elongated in the longitudinal direction including the vertical direction in addition to the horizontal direction as depicted in the drawings, wherein the synthesis gas discharging hole  163  communicates with the center of the opening/closing chamber  161  and the upper passage  164  communicated with the upper introduction chamber  11  and the lower passage  165  communicated with the outer chamber  13  are formed at both lateral sides. 
         [0042]    The opening/closing piston  162  come in close contact with the inner surface of the opening/closing chamber  161  for creating an air-tight seal and is pushed and pulled by a piston rod  166  to open and close the passages communicated with the introduction chamber  11  and the outer chamber  13 . 
         [0043]    A plurality of opening/closing pistons  162  is provided to open and close the passages  164  and  165  communicated with the introduction chamber  11  and the outer chamber  13 , respectively, and includes respective piston rods  166  extending out, as illustrated in  FIGS. 3A and 3B , to work individually or includes a connector bar  167  connecting the two opening/closing pistons  162  to each other as shown in  FIG. 3C  to integrate the two opening/closing pistons  162  and the connecting rod  166  extending from any side thereof such that the opening/closing pistons  162  may move. When the two opening/closing pistons  162  are integrated with each other, the three passages of the opening/closing chamber  161  are arranged in the same interval such that the length of the connector bar may correspond to the interval between the passages of the opening/closing chamber  161  so that one passage is opened when another passage is closed. 
         [0044]    The first gasification agent injection hole  14  may be configured to control the feed of the gasification agent. 
         [0045]    Referring to  FIG. 4 , the first gasification agent injection hole  14  according to the present invention includes an outer tube  141  with a flange formed at an outwardly protruding end, an inner tube  142  inserted in the outer tube  141 , a seal  144  sliding within the inner tube  142  to open and close gasification agent introduction holes formed in the inner tube  142 , and a cylinder  146  moving the seal  144  and controls the feed of the gasification agent introducing into the gasifier. 
         [0046]    The outer tube  141  has an outwardly protruding closed end, a closed end connected to the gasification chamber  12 , and a plurality of axial or ring-shaped gasification agent introduction holes  143  formed on the outer surface. 
         [0047]    The inner tube  142  is inserted into the outer tube  141 , has an end located within the gasification chamber  12 , the outwardly protruding end, and a plurality of axial or ring-shaped gasification agent introduction holes  143  formed on the outer surface. 
         [0048]    Thus, the gasification agent, that is, air is introduced into the outer tube  141  via the gasification agent introduction holes  143  of the outer tube  141 , is further introduced into the inner tube  142  through the gasification agent introduction holes  143  of the inner tube  142 , and is finally fed into the gasification chamber  12 . 
         [0049]    The seal  144  installed in the inner tube  142  is moved in the axial direction to control the feed of the gasification agent to be introduced. For example, the seal  144  has a length in the inner tube  142  to close all the gasification agent introduction holes  143  elongating in the axial direction and moves forward or backward from the cylinder  146  by a seal rod coupled to the rear side of the seal  144  to sequentially open and close the gasification agent introduction holes  143  such that the feed of the introduced gasification agent can be controlled according to the degree of opening the gasification agent introduction holes  143 . 
         [0050]    In this configuration, the cylinder  146 , as shown in  FIG. 4 , may be installed in the same axial direction as that of the first gasification agent injection hole  14  or in the different axial direction from that of the first gasification agent injection hole  14  as shown in  FIG. 5 , and the seal rods  145  are connected to the cylinder  146  with a joint  147  so that width of the apparatus can be minimized. 
         [0051]    Meanwhile, the synthesis gas produced in the gasifier  10  is filtered by the filtration device  20 . As illustrated in  FIG. 1 , the filtration device  20  includes a cyclone  21  separating solid particles from the synthesis gas discharged from the gasifier, a scrubber  22  spraying washing water to the synthesis gas discharged from the cyclone  21  to remove foreign matter from the synthesis gas, a filter  23  filtering fine particles contained in the synthesis gas passing through the scrubber  22 , and a bypass  24  bypassing the synthesis gas passing through the cyclone  21  directly to the feed controller  30  during the upflow gasification reaction. 
         [0052]    The cyclone  21  is a device that separates large-sized solid particles and is basically used to filter the synthesis gas produced during the upflow or downflow gasification. 
         [0053]    The synthesis gas passing through the cyclone  21  is directly fed into the feed controller  30  via the bypass  24  or to the scrubber  22 . That is, the synthesis gas produced during the upflow gasification is fed into the feed controller  30  through the bypass  24  to be used only for the combustion boiler  40 , while the synthesis gas produced during the downflow gasification passes through the scrubber  22  and the filter  23  and is finally fed into the gas engine  50  through the feed controller  30  such that electric power is generated. In this case, feed of the synthesis gas discharged from the cyclone  21  to the bypass  24  and the scrubber  22  may be controlled by a distribution valve installed on a transfer pipe, and the passage line passing through the distributed bypass or the scrubber may be directly communicated with the feed controller  30  or combined into one by a combination valve before the communication with the feed controller. 
         [0054]    Moreover, the synthesis gas fed into the gas engine  50  by the feed controller  30  may be temporally reserved in a tank  51  and surplus synthesis gas is fed into the combustion boiler  40  to generate heat with water steam when the reservation of the synthesis gas exceeds a limit. In addition, the combustion boiler  40 , as described above, includes oil substitute in a wide sense in addition to a boiler. 
         [0055]    Coolant of the gas engine  50  is utilized as reactive water of the combustion boiler  40  so that an arrangement of the gas engine can be utilized. 
         [0056]    As illustrated in  FIG. 6 , the method of driving a gasifying apparatus according to an embodiment of the present invention includes the steps of: introducing fuel through a fuel feeder to be accumulated in a gasification chamber of a gasifier while blocking oxygen from being introduced; determining whether synthesis gas, which is produced by gasifying the fed fuel, is used for power generation or for a combustion boiler; communicating a synthesis gas discharging hole of a passage opening/closing unit with an introduction chamber or an outer chamber according to the determination; performing upflow gasification or downflow gasification by feeding a gasification agent through a first or a second gasification agent injection hole according to the determination; producing the synthesis gas by performing the upflow gasification or the downflow gasification according to the performance of the upflow gasification or the downflow gasification; filtering foreign matter contained in the product synthesis gas; and generating electric power by feeding the synthesis gas filtered in the filtration into the gas engine or recovering heat by feeding the filtered synthesis gas into the combustion boiler. 
         [0057]    Moreover, in the synthesis gas production, the method may further include the sub-step of moving the seal into the inner tube to adjust the number of first gasification agent injection apertures such that the feed of the gasification agent is controlled in the first gasification agent injection hole  14  having the inner tube and the outer tube, which are formed with a plurality of first gasification agent injection apertures on the outer surface, when the downflow gasification is performed. 
         [0058]    Moreover, in the filtration, the synthesis gas produced during the downflow gasification passes through the cyclone, the scrubber, and the filter and is fed into the feed controller so that the synthesis gas may be used in power generation, while the synthesis gas produced during the upflow gasification passes through only the cyclone and is fed into the feed controller so that the synthesis gas may be used in heat recovery by the combustion boiler. 
         [0059]    Operations during the upflow gasification will be described with reference to  FIGS. 1 and 7 . 
         [0060]    First, fuel is fed through the fuel feeder  111  such that the fuel is accumulated in the gasification chamber  12  of the gasifier  10 , the gasification agent is forcibly injected into the second gasification agent injection hole  15  through the FD fan  70 , and at the same time, the passage opening/closing unit  16 , as shown in  FIG. 3B , blocks the passage  165  communicated with the outer chamber  13  and opens the passage  164  communicated with the introduction chamber  11  such that the synthesis gas discharging hole  163  communicates with the introduction chamber  11 . 
         [0061]    When the passages are formed as described above, the gasification agent injected through the second gasification agent injection hole  15  is fed toward the introduction chamber  11  through the lower side of the gasification chamber  12  so that air stream becomes an upflow. The accumulated fuel in the gasification chamber  12  has a combustion layer, a gasification layer, a thermal decomposition layer, and a dry layer from the lowest layer to the uppermost layer such that heat transfer may be performed. In this case, the combustion gas in the combustion layer moves upward and carbon in the fuel reacts with carbon dioxide (CO 2 ) and water vapor to produce synthesis gas, and the product synthesis gas is discharged out of the synthesis gas discharging hole  163  through the passage opening/closing unit  16 . 
         [0062]    The synthesis gas discharged from the synthesis gas discharging hole  163  is fed into the feed controller  30  through the bypass  24  after large-sized grains contained in the synthesis gas are separated while passing through the cyclone  21 , and the feed controller feeds the synthesis gas to the combustion boiler  40  to generate heat. 
         [0063]    Operations during the downflow gasification will be described with reference to  FIGS. 1 and 8 . 
         [0064]    First, the fuel is fed by the fuel feeder  111  to be accumulated in the gasification chamber  12  of the gasifier  10 , and the passage opening/closing unit  16 , as illustrated in  FIG. 3A , opens the passage  165  communicated with the outer chamber  13  and blocks the passage  164  communicated with the introduction chamber  11  such that the synthesis gas discharging hole  163  communicates with the outer chamber  13  and closes the second gasification agent injection hole  15 . 
         [0065]    When the ID fan  60  installed at the rear end of the filtration device  20  is driven, air stream becomes a downflow such that the gasification agent (air) is introduced from the first gasification agent injection hole  14  by the suctioning force of the ID fan  60 , is fed to the middle portion of the gasification chamber  12 , and moves to the outer chamber  13  through the lower side of the gasification chamber  12 , while the seal  144  in the first gasification agent injection hole  14  moves to adjust the number of opened gasification agent introduction holes  143  such that the quantity of the gasification agent fed in the form of introducing downflow can be controlled. 
         [0066]    Moreover, the fuel accumulated in the gasification chamber  12 , to the middle portion of which the gasification agent is introduced, forms the combustion layer, the lower side of the combustion layer to which maximum combustion heat is supplied forms the gasification layer, the upper side of the combustion layer to which heat of the combustion layer is transferred forms the thermal decomposition layer, and the upper side of the thermal decomposition layer forms the dry layer. The synthesis gas discharged through the lower end of the gasification chamber moves upward along the inner wall of the outer chamber  13  and is discharged out through the synthesis gas discharging hole of the passage opening/closing unit  16 . 
         [0067]    The synthesis gas discharged through the synthesis gas discharging hole  163  passes through the cyclone  21  while separating large-sized grains contained therein, passes through the scrubber  22  and the filter  23  sequentially such that foreign matter is removed as much as possible, and is fed into the feed controller  30 . 
         [0068]    The feed controller  30  feeds the synthesis gas into the gas engine  50  such that power generation is performed. In this case, the tank  51  is installed between the feed controller  30  and the gas engine  50  such that the synthesis gas can be steadily fed to the gas engine  50 . Further, when the synthesis gas produced for the gas engine is excessively produced, the surplus thereof may be fed to the combustion boiler  40  to generate heat. 
         [0069]    Hereinafter, the present invention will be described through preferred embodiments in detail. 
       Embodiment 
       [0070]    As illustrated in  FIG. 1 , in the gasifying apparatus according to the embodiment of the present invention, the position and direction of injecting air are controlled to restrict the generation of tar and flow of the synthesis gas is changed by the opening/closing piston in the passage opening/closing unit  16  of the gasifier, as shown in  FIGS. 3A and 3B , for the purpose of generating heat and electric power. 
         [0071]    Fuel fed to the gasifier has compositions and calories as listed in Table 1, operating conditions of the gasifier are listed in Table 2, compositions and calories of the synthesis gas produced by injection the fuel and by operating the gasifier are listed in Table 3, and graphs exhibiting operation results of the upflow gasifier and the downflow gasifier are illustrated in  FIGS. 9 and 10 . 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 Proximate analysis (wt %) 
                   
               
             
          
           
               
                   
                 Moisture 
                 Voltaile 
                   
                 Fixed carbon 
                 HHV 
               
               
                 Sample 
                 (M) 
                 matter (V.M) 
                 Ash 
                 (F.C) 
                 (kcal/kg) 
               
               
                   
               
             
          
           
               
                 Chinese coal 
                 0.81 
                 7.18 
                 12.44 
                 79.57 
                 7,280 
               
               
                 Wood chips 
                 21.6 
                 60.14 
                 3.85 
                 14.34 
                 4,130 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                 Feed of fuel 
                 Feed of air 
                 Max. temp. of 
               
               
                   
                 Fuel 
                 (kg/h) 
                 (Nm 3 /h) 
                 gasifier (° C.) 
               
               
                   
                   
               
             
             
               
                   
                 Chinese coal 
                 10-15 
                 20-30 
                 1,000-1,200 
               
               
                   
                 Wood chips 
                 40-50 
                 50-60 
                 700-800 
               
               
                   
                 (upflow) 
               
               
                   
                 Wood chips 
                 60-70 
                 75-85 
                 800-900 
               
               
                   
                 (downflow) 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                   
                   
                   
                 HHV 
               
               
                 Sample 
                 H 2  (%) 
                 CO (%) 
                 CO 2  (%) 
                 CH 4  (%) 
                 (kcal/Nm 3 ) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Chinese coal 
                 17.4 
                 20.7 
                 11.9 
                 1.6 
                 1,240 
               
               
                 (upflow) 
               
               
                 Wood chips 
                 7.8 
                 25.0 
                 8.9 
                 3.0 
                 1,213 
               
               
                 (upflow) 
               
               
                 Wood chips 
                 14.5 
                 17.3 
                 16.0 
                 2.2 
                 1,117 
               
               
                 (downflow) 
               
               
                   
               
             
          
         
       
     
         [0072]    As listed in Table 3, production of hydrogen and carbon dioxide in the downflow gasifier is higher than that in the upflow gasifier and the higher heating value (HHV) in the upflow gasifier is higher than that in the downflow gasifier. 
         [0073]    Moreover, the quantity of tar produced by variable operation of the gasifiers is compared and analyzed. 
         [0074]    Tar is collected from sampling ports installed to the synthesis gas discharging holes of the gasifiers by a method as illustrated in  FIG. 11 , based on Guideline for Sampling and Analysis of Tar and Particles in Biomass Producer Gases Version 3.3 proposed J. P. A. Neeft. 
         [0075]    Tar solution in an impinger is filtered with a paper filter and tar attached on the inner wall of the impinger is resolved with isopropanol collected solution distilled by a distiller. 
         [0076]    When matter remaining after the distillation is defined as tar and a concentration of the tar is obtained from a sampling gas flowrate, the quantity of tar produced by the gasifying apparatus according to the present invention ranges 100 to 150 g/Nm 3  of fuel fed in the upflow gasifier, while the quantity of tar produced by the downflow gasifier ranges 3.9 to 4.4 g/Nm 3 . The synthesis gas produced by the downflow gasifier could be used in the gas engine by reforming a catalyst or by performing wet filtration. 
         [0077]    Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.