Abstract:
The coal deactivation apparatus including: a separating device that separates out a portion of the beneficiated coal deactivated in the main treatment apparatus; a main evaluation apparatus into which the sample of the beneficiated coal separated out by the separating apparatus is supplied; a blower and heater that supply air at the evaluation temperature to the main evaluation apparatus; a temperature sensor that detects the temperature of the air that has heat-treated the sample in the main evaluation apparatus; and a control unit that, when the temperature of the air is at or below the lower limit on the basis of information from the temperature sensor, determines whether or not the temperature of the process gas is at or below the lower limit and if the process gas temperature exceeds the lower limit, controls the heater to reduce the temperature of the process gas by a prescribed value.

Description:
TECHNICAL FIELD 
     The present invention relates to a coal inactivation system configured to inactivate coal by heating the coal with a treatment gas containing oxygen. 
     BACKGROUND ART 
     Low rank coals (low grade coals), coals having a high moisture content such as lignite and sub-bituminous coals, are abundant. However, the heating value per unit weight is small, and the transportation efficiency is low. Accordingly, such coal is heated and dried to increase the heating value per unit weight, and also compression-molded to improve the handling. 
     Meanwhile, the low grade coal thus heated is likely to adsorb water. In addition, a carboxyl group and the like are released from the surface, and radicals and the like are generated on the surface. This increases the surface activity, promoting a reaction with oxygen in air. As a result, spontaneous combustion may occur due to a reaction heat generated by the reaction. 
     For this reason, for example, the following inactivation treatment is carried out. Specifically, low grade coal is dried and pyrolyzed. After tar is separated from the pyrolyzed coal, the pyrolyzed coal is heated (approximately 150 to 170° C.) in a low oxygen atmosphere (oxygen concentration: approximately around 10%) to partially oxidize the surface of the pyrolyzed coal, thereby decreasing the surface activity of the pyrolyzed coal. By such an inactivation treatment, the coal is reformed to prevent spontaneous combustion of the coal (see, for example, the following Patent Literature 1, etc.). 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: Japanese Patent Application Publication No. Hei 11-310785 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     Meanwhile, the composition of coal varies, depending on the mining site where the coal is extracted. 
     Accordingly, in the inactivation treatment as described above, various treatment conditions such as an oxygen concentration in an atmosphere, a temperature of the atmosphere, and a treatment period are set so that coals of any composition can be inactivated sufficiently. As a result, a coal which can be inactivated sufficiently under relatively wide treatment conditions is also inactivated under relatively strict treatment conditions; hence, the treatment cost is increased wastefully. 
     Accordingly, an object of the present invention is to provide a coal inactivation system capable of readily inactivating coals of various compositions under necessary and sufficient conditions. 
     Solution to Problem 
     In order to achieve the above-described object, a coal inactivation system according to a first invention is a coal inactivation system configured to inactivate coal by heating the coal with a treatment gas containing oxygen, characterized in that the coal inactivation system comprises: a treatment apparatus body, to inside of which the coal is supplied; treatment gas-supply means configured to supply the treatment gas to the inside of the treatment apparatus body; treatment gas-oxygen concentration-adjustment means configured to adjust an oxygen concentration Oc in the treatment gas; treatment gas-temperature-adjustment means configured to adjust a temperature Tc of the treatment gas; fractionation means configured to fractionate a portion of the coal inactivated in the treatment apparatus body; an evaluation apparatus body, to inside of which a sample of the coal fractionated by the fractionation means is supplied; test gas-supply means configured to supply a test gas having an evaluation temperature Tt to the inside of the evaluation apparatus body; test gas-temperature-detection means configured to detect a temperature Te of the test gas having heated the sample in the evaluation apparatus body; and control means configured to, based on information from the test gas-temperature-detection means, when the temperature Te of the test gas is equal to or higher than a higher limit value Teh, judge whether or not the oxygen concentration Oc of the treatment gas is equal to or higher than a higher limit value Oh, if the oxygen concentration Oc of the treatment gas is lower than the higher limit value Oh, control the treatment gas-oxygen concentration-adjustment means in such a manner as to increase the oxygen concentration Oc of the treatment gas by a given value Ofu, and if the oxygen concentration Oc of the treatment gas is equal to or higher than the higher limit value Oh, further judge whether or not the temperature Tc of the treatment gas is equal to or higher than a higher limit value Th, and control the treatment gas-temperature-adjustment means in such a manner as to increase the temperature Tc of the treatment gas by a given value Tfu if the temperature Tc of the treatment gas is lower than the higher limit value Th, and when the temperature Te of the test gas is equal to or lower than a lower limit value Tel, judge whether or not the temperature Tc of the treatment gas is equal to or lower than a lower limit value Tl, if the temperature Tc of the treatment gas is higher than the lower limit value Tl, control the treatment gas-temperature-adjustment means in such a manner as to decrease the temperature Tc of the treatment gas by a given value Tfd, if the temperature Tc of the treatment gas is equal to or lower than the lower limit value Tl, further judge whether or not the oxygen concentration Oc of the treatment gas is equal to or lower than a lower limit value Ol, and control the treatment gas-oxygen concentration-adjustment means in such a manner as to decrease the oxygen concentration Oc of the treatment gas by a given value Ofd if the oxygen concentration Oc of the treatment gas is higher than the lower limit value Ol. 
     A coal inactivation system according to a second invention is the coal inactivation system according to the first invention, characterized in that, when the temperature Te of the test gas is equal to or lower than the lower limit value Tel, the control means controls the treatment gas-oxygen concentration-adjustment means and the treatment gas-temperature-adjustment means in such a manner as to set the oxygen concentration Oc and the temperature Tc of the treatment gas at the lower limit values Ol and Tl, respectively, if the temperature Tc of the treatment gas is equal to or lower than the lower limit value Tl while the oxygen concentration Oc of the treatment gas is equal to or lower than the lower limit value Ol. 
     A coal inactivation system according to a third invention is the coal inactivation system according to any one of the first and the second inventions, characterized in that, when the temperature Te of the test gas is higher than the lower limit value Tel but lower than the higher limit value Teh, the control means controls the treatment gas-oxygen concentration-adjustment means and the treatment gas-temperature-adjustment means in such a manner as to maintain the oxygen concentration Oc and the temperature Tc of the treatment gas as they are. 
     A coal inactivation system according to a fourth invention is the coal inactivation system according to any one of the first to the third inventions, characterized in that the coal inactivation system further comprises test gas-carbon dioxide concentration-detection means configured to detect a carbon dioxide concentration Ce of the test gas having heated the sample in the evaluation apparatus body, and when the temperature Te of the test gas is higher than the lower limit value Tel but lower than the higher limit value Teh, the control means, based on information from the test gas-carbon dioxide concentration-detection means, if the carbon dioxide concentration Ce in the test gas is equal to or higher than a higher limit value Ceh, judges again whether or not the oxygen concentration Oc of the treatment gas is equal to or higher than the higher limit value Oh, and if the carbon dioxide concentration Ce in the test gas is equal to or lower than a lower limit value Cel, judges again whether or not the temperature Tc of the treatment gas is equal to or lower than the lower limit value Tl. 
     A coal inactivation system according to a fifth invention is the coal inactivation system according to the fourth invention, characterized in that, when the temperature Te of the test gas is higher than the lower limit value Tel but lower than the higher limit value Teh, the control means controls the treatment gas-oxygen concentration-adjustment means and the treatment gas-temperature-adjustment means in such a manner as to maintain the oxygen concentration Oc and the temperature Tc of the treatment gas as they are if the carbon dioxide concentration Ce in the test gas is higher than the lower limit value Cel but lower than the higher limit value Ceh based on the information from the test gas-carbon dioxide concentration-detection means. 
     Advantageous Effects of Invention 
     Even when the composition of coal supplied to the treatment apparatus body varies from time to time, the coal inactivation system according to the present invention is capable of readily inactivating coals of such compositions under necessary and sufficient conditions. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic configuration diagram of a main embodiment of a coal inactivation system according to the present invention. 
         FIG. 2  is a control flowchart of the coal inactivation system in  FIG. 1 . 
         FIG. 3  is a control flowchart continued to  FIG. 2 . 
         FIG. 4  is a control flowchart continued to  FIG. 2 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of a coal inactivation system according to the present invention will be described based on the drawings. However, the present invention is not limited to the following embodiments explained based on the drawings. 
     &lt;Main Embodiment&gt; 
     A main embodiment of the coal inactivation system according to the present invention will be described based on  FIGS. 1 to 4 . 
     As shown in  FIG. 1 , a nitrogen gas supply source  112 , which is an inert gas supply source, is connected to a lower portion of a treatment apparatus body  111  via a blower  113  and a heater  114 . Pyrolyzed coal  1 , coal obtained by drying and pyrolyzing low grade coal, is supplied to the inside of the treatment apparatus body  111  through an upper portion thereof. A blower  115  configured to supply air  102  is connected between the blower  113  and the heater  114 . 
     In other words, operating the blowers  113  and  115  makes it possible to heat a treatment gas  103  with the heater  114  and supply the treatment gas  103  to the inside of the treatment apparatus body  111 , the treatment gas  103  being a mixture of a nitrogen gas  101  from the nitrogen gas supply source  112  with the air  102  from the outside. Here, the oxygen gas concentration in the treatment gas  103  can be adjusted by adjusting amounts of the nitrogen gas  101  and the air  102  supplied from the blowers  113  and  115 , while the temperature of the treatment gas  103  can be adjusted by adjusting the heater  114 . 
     A filter  116  is connected to the upper portion of the treatment apparatus body  111 . The filter  116  is configured to remove dust in the treatment gas  103  used in and discharged from the inside of the treatment apparatus body  111 . 
     A fractionation device  117  is disposed to the lower portion of the treatment apparatus body  111 . The fractionation device  117  is fractionation means configured to fractionate only a small portion of reformed coal  2  inactivated in and discharged from the treatment apparatus body  111 . Most of the reformed coal  2  not fractionated by the fractionation device  117  is collected into an unillustrated vessel such as a container. A sample  3  of the small portion of the reformed coal  2  fractionated by the fractionation device  117  is supplied to the inside of an evaluation apparatus body  121  of an evaluation apparatus  120  through an upper portion thereof. The evaluation apparatus  120  is configured to evaluate the inactivation state of the sample  3 . 
     A blower  122  configured to supply an air  102 , a test gas, is connected to a lower portion of the evaluation apparatus body  121  via a heater  123 . A filter  124  is connected to the upper portion of the evaluation apparatus body  121 . The filter  124  is configured to remove dust in the air  102  used in and discharged from the inside of the evaluation apparatus body  121 . The reformed coal  2  evaluated in the inside of the evaluation apparatus body  121  is discharged from the lower portion thereof. 
     Between the evaluation apparatus body  121  and the dust removal filter  124 , a temperature sensor  125  and a CO 2  sensor  126  are provided. The temperature sensor  125  is test gas-temperature-detection means configured to detect a temperature of the air  102 , and the CO 2  sensor  126  is test gas-carbon dioxide concentration-detection means configured to detect a carbon dioxide concentration in the air  102 . Each of these sensors  125 ,  126  is electrically connected to an input section of a controller  130  that is control means. Further, a control board  131  that is input means is electrically connected to the input section of the controller  130 . An output section of the controller  130  is electrically connected to each of the blowers  113 ,  115 ,  122 , the heaters  114 ,  123 , and the fractionation device  117 . The controller  130  is capable of controlling the operation of each of the blower  122 , the heater  123 , and the fractionation device  117  based on information from the control board  131 , and is also capable of controlling the operation of each of the blowers  113 ,  115  and the heater  114  based on information from the control board  131  and information from the sensors  125 ,  126  (the details will be described later). 
     Note that, as the treatment apparatus body  111 , any of various types that have heretofore been utilized for inactivation treatment can be employed; examples thereof include those for batch processing, those for continuous processing such as sintering machine type (mesh conveyor type) and circular grate type described in Patent Literature  1  above, etc., and other similar types. Moreover, as the evaluation apparatus body  121  of the evaluation apparatus  120 , any type can be employed, including those for batch processing, continuous processing such as sintering machine type (mesh conveyor type) and circular grate type having a similar structure to that of the treatment apparatus body  111  but smaller than the treatment apparatus body  111 , and other types, as long as the supplied sample  3  can be exposed to an atmosphere at a predetermined temperature for a predetermined period. Further, as the fractionation device  117 , any type can be employed such as a movable gate or a movable constant-volume cylinder, as long as it can fractionate a portion of the reformed coal  2  discharged from the treatment apparatus body  111 . 
     In the present embodiment as described above, the nitrogen gas supply source  112 , the blowers  113 ,  115 , and so forth constitute treatment gas-supply means; the blowers  113 ,  115 , and so forth constitute treatment gas-oxygen concentration-adjustment means, the heater  114  and so forth constitute treatment gas-temperature-adjustment means; and the blower  122 , the heater  123 , and so forth constitute test gas-supply means. 
     Next, description will be given of the operations of the coal inactivation system  100  described above. 
     When pyrolyzed coal  1  is supplied to the inside of the treatment apparatus body  111  and the control board  131  receives operation-starting information, the controller  130  controls the blowers  113 ,  115  and the heater  114  in such a manner that the inside of the treatment apparatus body  111  is supplied with the treatment gas  103  having an oxygen concentration Oc of a standard value Os (for example, 10%) and a temperature Tc of a standard value Is (for example, 150° C.) on the basis of the information from the control board  131  (S 1  in  FIG. 2 ), and also controls the blower  122  and the heater  123  in such a manner that the inside of the evaluation apparatus body  121  is supplied with the air  102  (oxygen concentration: approximately 20%) having an evaluation temperature Tt (for example, 150° C.) (S 2  in  FIG. 2 ). 
     The surface of the pyrolyzed coal  1  supplied to the inside of the treatment apparatus body  111  is partially oxidized with the treatment gas  103 , and the activity is decreased. Thus, the reformed coal  2  is formed. The reformed coal  2  having been subjected to such an inactivation treatment for a predetermined period (for example, 20 minutes) is discharged from the lower portion of the treatment apparatus body  111 , and is collected into the vessel. In this event, the controller  130  controls the fractionation device  117  based on the treatment period and so forth in such a manner that only a small portion of the reformed coal  2  discharged from the treatment apparatus body  111  is fractionated as the sample  3  for each predetermined period or continuously and is supplied to the evaluation apparatus body  121  for each predetermined period or continuously (S 3  in  FIG. 2 ). 
     The sample  3  supplied to the evaluation apparatus body  121  is heated by the air  102  for a given period (for example, 10 minutes). The temperature and the carbon dioxide concentration of the air  102  heated by the sample  3  are measured by the sensors  125 ,  126  (S 4  in  FIG. 2 ). 
     Based on the information from the temperature sensor  125 , the controller  130  judges whether a temperature Te of the air  102  is equal to or lower than a lower limit value Tel (for example, 150° C.) (Te≦Tel), equal to or higher than a higher limit value Teh (for example, 200° C.) (Teh≦Te), or higher than the lower limit value Tel but lower than the higher limit value Teh (Tel&lt;Te&lt;Teh) (S 5  in  FIG. 2 ). 
     If the temperature Te (for example, 160° C.) is higher than the lower limit value Tel but lower than the higher limit value Teh (Tel&lt;Te&lt;Teh), the controller  130  successively judges whether a carbon dioxide concentration Ce in the air  102  is equal to or lower than a lower limit value Cel (for example, 0.1%) (Ce≦Cel), equal to or higher than a higher limit value Ceh (for example, 2%) (Ceh≦Ce), or higher than the lower limit value Cel but lower than the higher limit value Ceh (Cel&lt;Ce&lt;Ceh) based on the information from the CO 2  sensor  126  (S 6  in  FIG. 2 ). 
     Then, if the carbon dioxide concentration Ce (for example, 1%) is higher than the lower limit value Cel but lower than the higher limit value Ceh(Cel &lt;Ce &lt;Ceh), the controller  130  determines that the fractionated sample  3  is not burnt with the air  102  having the evaluation temperature Tt, in other words, the reformed coal  2  is sufficiently inactivated in the treatment apparatus body  111  under the above conditions. The controller  130  controls the blowers  113 ,  115  and the heater  114  in such a manner as to maintain the oxygen concentration Oc and the temperature Tc of the treatment gas  103  as they are (S 7  in  FIG. 2 ), and checks whether or not an operation-ending signal is inputted (S 8  in  FIG. 2 ). Then, the processing is returned to step S 5  above, and the temperature Te of the air  102  is measured again for a sample  3  newly supplied to the evaluation apparatus body  121  by the fractionation device  117 . 
     Meanwhile, in step S 5  above, if the temperature Te (for example, 200° C.) is equal to or higher than the higher limit value Teh (Teh≦Te), the controller  130  determines that the sample  3  is with burnt with the air  102  having the evaluation temperature Tt, and judges whether or not the oxygen concentration Oc (for example, 10%) of the treatment gas  103  is equal to or higher than a higher limit value Oh (for example, 16%) (Oh≦Oc) (S 9  in  FIG. 3 ). If the oxygen concentration Oc is lower than the higher limit value Oh (Oc&lt;Oh), the controller  130  controls the blowers  113 ,  115  in such a manner as to increase the oxygen concentration Oc of the treatment gas  103  by a given value Ofu (for example, 2%) (S 10  in  FIG. 3 ). 
     Then, the processing is returned to step S 5  above, and the temperature Te of the air  102  is measured again for a sample  3  which is inactivated in the treatment apparatus body  111  under the above conditions, and which is newly supplied to the evaluation apparatus body  121  by the fractionation device  117 . 
     Meanwhile, in step S 9  above, if the oxygen concentration Oc (for example, 16%) is equal to or higher than the higher limit value Oh (for example, 16%) (Oh≦Oc), the controller  130  judges whether or not the temperature Tc (for example, 150° C.) of the treatment gas  103  is equal to or higher than a higher limit value Th (for example, 170° C.) (Th≦Tc) (S 11  in  FIG. 3 ). If the temperature Tc is lower than the higher limit value Th (Tc&lt;Th), the controller  130  controls the heater  114  in such a manner as to increase the temperature Tc of the treatment gas  103  by a given value Tfu (for example, 10° C.) (S 12  in  FIG. 3 ). 
     Then, the processing is returned to step S 5  above, and the temperature Te of the air  102  is measured again for a sample  3  which is inactivated in the treatment apparatus body  111  under the above conditions, and which is newly supplied to the evaluation apparatus body  121  by the fractionation device  117 . 
     Note that, in step S 6  above, if the carbon dioxide concentration Ce (for example, 2%) is equal to or higher than the higher limit value Ceh (for example, 2%) (Ceh Ce), the controller  130  determines that the fractionated sample  3  is also burnt with the air  102  having the evaluation temperature Tt. Then, the processing is moved to step S 9  above, and steps S 10  to S 12  above as well as step S 9  are executed. 
     On the other hand, in step S 5  above, if the temperature Te (for example, 150° C.) is equal to or lower than the lower limit value Tel (Te≦Tel), the controller  130  determines that the reformed coal  2  is inactivated excessively with the treatment gas  103 , and judges whether or not the temperature Tc (for example, 170° C.) of the treatment gas  103  is equal to or lower than a lower limit value Tl (for example, 150° C.) (Tc≦Tl) (S 13  in  FIG. 4 ). If the temperature Tc is higher than the lower limit value Tl (Tl&lt;Tc), the controller  130  controls the heater  114  in such a manner as to decrease the temperature Tc of the treatment gas  103  by a given value Tfd (for example, 10° C.) (S 14  in  FIG. 4 ). 
     Then, the processing is returned to step S 5  above, and the temperature Te of the air  102  is measured again for a sample  3  which is inactivated in the treatment apparatus body  111  under the above conditions, and which is newly supplied to the evaluation apparatus body  121  by the fractionation device  117 . 
     Meanwhile, in step S 13  above, if the temperature Tc (for example, 150° C.) is equal to or lower than the lower limit value Tl (for example, 150° C.) (Tc≦Tl), the controller  130  judges whether or not the oxygen concentration Oc of the treatment gas  103  (for example, 10%) is equal to or lower than a lower limit value Ol (for example, 6%) (Oc≦Ol) (S 15  in  FIG. 4 ). If the oxygen concentration Oc is higher than the lower limit value Ol (Ol&lt;Oc), the controller  130  controls the blowers  113 ,  115  in such a manner as to decrease the oxygen concentration Oc of the treatment gas  103  by a given value Ofd (for example, 2%) (S 16  in  FIG. 4 ). 
     Then, the processing is returned to step S 5  above, and the temperature Te of the air  102  is measured again for a sample  3  which is inactivated in the treatment apparatus body  111  under the above conditions, and which is newly supplied to the evaluation apparatus body  121  by the fractionation device  117 . 
     Meanwhile, in step S 15  above, if the oxygen concentration Oc of the treatment gas  103  (for example, 6%) is equal to or lower than the lower limit value Ol (for example, 6%) (Oc≦Ol), the controller  130  controls the blowers  113 ,  115  and the heater  114  in such a manner as to set the oxygen concentration Oc and the temperature Tc of the treatment gas  103  at the lower limit values Ol and Tl, respectively (S 17  in  FIG. 4 ). 
     Then, the processing is returned to step S 5  above, and the temperature Te of the air  102  is measured again for a sample  3  which is inactivated in the treatment apparatus body  111  under the above conditions, and which is newly supplied to the evaluation apparatus body  121  by the fractionation device  117 . 
     Note that, in step S 6  above, if the carbon dioxide concentration Ce (for example, 0.1%) is equal to or lower than the lower limit value Cel (for example, 0.1%) (Ce≦Cel), the controller  130  determines that the reformed coal  2  is also inactivated excessively with the treatment gas  103 . Then, the processing is moved to step S 13  above, and steps S 14  to S 17  above as well as step S 13  are executed. 
     Hence, even when the composition of the pyrolyzed coal  1  supplied to the treatment apparatus body  111  varies from time to time, the coal inactivation system  100  according to the present embodiment is capable of readily inactivating pyrolyzed coal  1  of such compositions under necessary and sufficient conditions. 
     Thus, the coal inactivation system  100  according to the present embodiment is capable of inactivating pyrolyzed coals  1  of various compositions at low cost. 
     Incidentally, in the present embodiment, the result of evaluating, by the evaluation apparatus  120 , the sample  3  fractionated as a portion of the reformed coal  2  inactivated in the treatment apparatus body  111  is reflected in inactivation conditions for pyrolyzed coal  1  newly supplied to the treatment apparatus body  111 . Accordingly, the reformed coal  2  inactivated insufficiently may be formed in some cases. 
     Nevertheless, the amount of the reformed coal  2  formed by insufficient inactivation in such an event is quite small in comparison with the amount of the reformed coal sufficiently inactivated under almost the same treatment conditions, that is, the amount of treated low grade coal extracted from the same mining site. Accordingly, the amount is hardly problematic. In this respect, for example, the above reformed coal  2  inactivated insufficiently is supplied once more to and inactivated again in the treatment apparatus body  111  whose inactivation conditions are re-set to reflect the evaluation result by the evaluation apparatus  120 , so that sufficiently-inactivated reformed coal  2  can be formed. 
     &lt;Other Embodiments&gt; 
     Note that, in the above-described embodiment, the evaluation apparatus  120  is provided with the temperature sensor  125  and the CO 2  sensor  126 , and the controller  130  makes judgments again on the oxygen concentration Oc and the temperature Tc of the treatment gas  103 , according to the carbon dioxide concentration Ce in the air  102  on the basis of the information from the CO 2  sensor  126  (step S 6  above), when the temperature Te of the air  102  is higher than the lower limit value Tel but lower than the higher limit value Teh based on the information from the temperature sensor  125 . Nevertheless, as another embodiment, for example, the CO 2  sensor  126  is omitted, and when the temperature Te of the air  102  is higher than the lower limit value Tel but lower than the higher limit value Teh based on the information from the temperature sensor  125 , the blowers  113 ,  115  and the heater  114  are controlled in such a manner as to maintain the oxygen concentration Oc and the temperature Tc of the treatment gas  103  as they are, regardless of the carbon dioxide concentration Ce in the air  102 . To put it differently, step S 6  above may be omitted. 
     Moreover, in the above-described embodiment, the description has been given for the case where the controller performs control in such a manner that a portion of the reformed coal  2  discharged from the treatment apparatus body  111  is fractionated as the sample  3  by the movable fractionation device  117  for each predetermined period or continuously and is supplied to the evaluation apparatus body  121  for each predetermined period or continuously. Nevertheless, as another embodiment, for example, a portion of the reformed coal  2  discharged from the treatment apparatus body  111  may be fractionated as the sample  3  by a stationary type (fixed type) of fractionation means such as a fixed gate or a fixed scraper without being controlled by the control means and supplied to the evaluation apparatus body  121 . 
     Further, in the above-described embodiment, the treatment gas  103  having a desired oxygen concentration Oc is generated by mixing the nitrogen gas  101  with the air  102 . Nevertheless, as another embodiment, for example, by mixing the nitrogen gas  101  with an oxygen gas, the treatment gas  103  having a desired oxygen concentration may be generated. Nonetheless, as in the above-described embodiment, it is particularly preferable to generate the treatment gas  103  having a desired oxygen concentration by mixing the nitrogen gas  101  with the air  102  because this eliminates the need to prepare the oxygen gas only for the purpose. 
     Furthermore, it is needless to say that the nitrogen gas cylinder and so forth prepared just to generate the treatment gas  103  are usable as the nitrogen gas supply source  112 ; besides, it is also possible, for example, to use a pyrolysis gas (main component: nitrogen gas) which is a nitrogen gas supplied to a pyrolyzer to pyrolyze low grade coal and discharged from the pyrolyzer, and from which a volatile component, dust, and the like are separated thereafter. In this case, thermal energy newly applied to the treatment gas  103  can be saved for an inactivation treatment. 
     Furthermore, in the above-described embodiment, the air  102  is utilized as the test gas. Nevertheless, as another embodiment, it is possible, for example, to utilize a test gas having an oxygen concentration Oc higher than the higher limit value Oh (for example,  16 %) by mixing the nitrogen gas  101  with the air  102  as in the case of the treatment gas  103 . As the nitrogen gas source in this case, the above-described pyrolysis gas is also usable in addition to, although needlessly to say, a nitrogen gas from the nitrogen gas cylinder, as in the case of the treatment gas  103 . 
     Furthermore, in the above-described embodiment, the description has been given of the case where the pyrolyzed coal  1  is inactivated. Nevertheless, the present invention is not limited thereto, and is applicable to any inactivation treatment on coals as in the case of the above-described embodiment. 
     INDUSTRIAL APPLICABILITY 
     Even when the composition of coal supplied to the treatment apparatus body varies from time to time, the coal inactivation system according to the present invention is capable of readily inactivating coals of such compositions under necessary and sufficient conditions. Therefore, the present invention is applicable to the industry very usefully. 
     REFERENCE SIGNS LIST 
     
         
           1  PYROLYZED COAL 
           2  REFORMED COAL 
           3  SAMPLE 
           100  COAL INACTIVATION SYSTEM 
           101  NITROGEN GAS 
           102  AIR 
           103  TREATMENT GAS 
           111  TREATMENT APPARATUS BODY 
           112  NITROGEN GAS SUPPLY SOURCE 
           113  BLOWER 
           114  HEATER 
           115  BLOWER 
           116  FILTER 
           117  FRACTIONATION DEVICE 
           120  EVALUATION APPARATUS 
           121  EVALUATION APPARATUS BODY 
           122  BLOWER 
           123  HEATER 
           124  FILTER 
           125  TEMPERATURE SENSOR 
           126  CO 2  SENSOR 
           130  CONTROLLER 
           131  CONTROL BOARD