a process for improving tobacco raw material according to an embodiment of the invention comprises conducting extraction from tobacco raw material used in cigarette industry by solvent , removing harmful components and backfilling with the feed liquid to obtain the improved tobacco raw material . the process specifically comprises the following steps : 1 ) mixing stalks or cut stems ( tobacco raw material ) with a mixed solvent containing 65 % of purified water and 35 % of ethanol at a mass ratio of 1 : 6 ( tobacco raw material : solvent ), and then conduct an extraction at a temperature of 80 ° c . for 1 minute ; 2 ) conducting a solid - liquid separation for the tobacco raw material after extraction by means of squeezing until the dryness of tobacco raw material reaches 20 %; 3 ) loosening the tobacco raw material after solid - liquid separation to a sufficiently loose status , with the extract liquor after solid - liquid separation being used for manufacturing fertilizer but not in this process ; 4 ) preparing a backfilling feed liquid by the following steps : firstly , diluting by purified water 10 parts by mass of aqueous extract of natural tobacco and 15 parts by mass of alcohol extract of natural tobacco which are prepared by other extract liquor than in the present process , and mixing them uniformly , then removing the harmful components by nanofiltration membrane with a cut - off molecular - weight of 2000 dalton , and subsequently adding humectant or other functional agents allowed to be added in the tobacco production so as to obtain the backfilling feed liquid with a concentration thereof being controlled by 50 %; 5 ) adjusting the dryness of the tobacco raw material after solid - liquid separation to 40 %, spraying uniformly and backfilling the backfilling feed liquid to the tobacco raw material after solid - liquid separation with a backfilling mass ratio of 10 %, stirring the tobacco raw material and simultaneously squeezing them so as to have the tobacco raw material uniformly absorb the backfilling feed liquid , and then loosening the tobacco raw material ; 6 ) pre - drying by microwave the tobacco raw material after the backfilling until the dryness of the tobacco raw material reaches 70 %, followed by reducing the moisture to 11 % in an inflation process , thus obtaining the end products . the extraction operation in step 1 ) and the solid - liquid separation in step 2 ) are cycled twice before going to step 3 ). in step 3 ), using the extract liquor after solid - liquid separation of stalks or cut stems for manufacturing fertilizer comprises purifying and concentrating the extract liquor , adding therein one or several kinds of microbial agent such as bacteria , actinomycetes , fungus to ferment them in the extract liquor to obtain liquid organic fertilizer after fermentation . as shown in fig1 , an apparatus for the process for improving tobacco raw material in the first embodiment is a system composed of a plurality of interconnected independent devices comprising a material room , a solvent room , an extractor , a solid - liquid separator , a secondary material room , an extract producer , an extract room , a feed liquid preparing device , a room for collecting harmful substance , a room for distributing additional materials , a room for collecting fertilizer raw materials , a moisture content regulator , a feed liquid backfiller and a dryer , wherein the outlet of the material room and the liquid outlet of the solvent room are communicated with the inlet of the extractor , the outlet of the extractor is communicated with the inlet of the solid - liquid separator , the liquid outlet of the solid - liquid separator is communicated at one branch with the liquid inlet of the extract producer and at the other branch with the room for collecting fertilizer raw materials , the outlet of the extract producer is communicated with the inlet of the extract room , the outlet of the solid - liquid separator is communicated at one branch with the inlet of the secondary material room and at the other branch with the inlet of the moisture content regulator , the outlet of the secondary material room is communicated with the inlet of the extractor , the outlet of the moisture content regulator is communicated with the inlet of the feed liquid backfiller , the outlet of the extract room is communicated with the inlet of the feed liquid preparing device , the room for distributing additional material is communicated with the inlet of the feed liquid preparing device , the liquid outlet of the feed liquid preparing device is communicated with the liquid inlet of the feed liquid backfiller , the harmful substance outlet of the feed liquid preparing apparatus is communicated with the room for collecting harmful substance , the outlet of the feed liquid backfiller is communicated with the inlet of the dryer , and the outlet of the dryer is communicated with a production room . the connection between two of the above independent devices may be provided with , as necessary , a conveyer belt , a spiral propeller , an infusion pump , a delivery pipe , a detector or a delivery metering controller , etc . the solid - liquid separator is a squeezing dryer . the feed liquid preparing apparatus is provided with a separator having a ultrafiltration membrane for the separation of the harmful components . the feed liquid backfiller is provided with stirring and squeezing mechanism . the solid - liquid separator and the feed liquid backfiller , at the connection portion of the outlet thereof , are provided with a loosening means for conducting loosening operation . the moisture content regulator uses a heating evaporator or a humidifier , etc . the room for distributing additional material is a metering distribution system for various additional materials . a process for improving tobacco raw material according to an embodiment of the invention comprises conducting extraction from tobacco raw material used in cigarette industry by solvent , removing harmful components and backfilling with the feed liquid to obtain the improved tobacco raw material . the process specifically comprises the following steps : 1 ) mixing tobacco leaves or flakes ( tobacco raw material ) with a mixed solvent containing 97 % of purified water and 3 % of propanediol at the mass ratio of 1 : 30 ( tobacco raw material solvent ), and then conduct an extraction at a temperature of 50 ° c . for 80 minutes ; 2 ) conducting a solid - liquid separation for the tobacco raw material after extraction by means of centrifugation until the dryness of the tobacco raw material reaches 40 %; 3 ) using the extract liquor after the solid - liquid separation of the tobacco leaf or flake for preparing an extract of natural tobacco that can be used in this process ; 4 ) preparing a backfilling feed liquid by the following steps : firstly , diluting with purified water 5 parts by mass of aqueous extract of natural tobacco prepared by the extract liquor in the present process and 1 part by mass of the alcohol extract of natural tobacco prepared by an extract liquor obtained from other process , mixing them uniformly , and then removing the harmful components by using a combination of a nanofiltration membrane with a cut - off molecular - weight of 2000 dalton and an ultrafiltration membrane with a cut - off molecular - weight of 50000 dalton , and subsequently adding humectant or other functional agents allowed to be added in the tobacco production so as to obtain the backfilling feed liquid with a concentration thereof being controlled by 40 %; 5 ) adjusting the dryness of the tobacco raw material after the solid - liquid separation to 60 %, and then backfilling uniformly the backfilling feed liquid into the tobacco raw material after solid - liquid separation by means of immersion , in which the mass ratio of the backfilling is 120 %. 6 ) pre - drying by microwave the tobacco raw material after backfilling until the dryness of the tobacco raw material reaches 60 %, followed by reducing the moisture to 13 % by inflation process , thus obtaining the end product . as shown in fig2 , an apparatus for the process for improving tobacco raw material in the second embodiment is a system composed of a plurality of interconnected independent devices comprising a material room , a solvent room , an extractor , a solid - liquid separator , an extract producer , an extract room , a feed liquid preparing device , a room for collecting harmful substance , a room for distributing additional material , a room for collecting fertilizer raw materials , a moisture content regulator , a feed liquid backfiller and a dryer , wherein the outlet of the material room and the liquid outlet of the solvent room are communicated with the inlet of the extractor , the outlet of the extractor is communicated with the inlet of the solid - liquid separator , the liquid outlet of the solid - liquid separator is communicated at one branch with the liquid inlet of the extract producer and at the other branch with the room for collecting fertilizer raw materials , the outlet of the extract producer is communicated to with the inlet of the extract room , the outlet of the solid - liquid separator is communicated at one branch with the inlet of the secondary material room and at the other branch with the inlet of the moisture content regulator , the outlet of the secondary material room is communicated with the inlet of the extractor , the outlet of the moisture content regulator is communicated with the inlet of the feed liquid backfiller , the outlet of the extract room is communicated with the inlet of the feed liquid preparing device , the room for distributing additional material is communicated with the inlet of the feed liquid preparing device , the liquid outlet of the feed liquid preparing device is communicated with the liquid inlet of the feed liquid backfiller , the harmful substance outlet of the feed liquid preparing apparatus is communicated with the room for collecting harmful substance , the outlet of the feed liquid backfiller is communicated with the inlet of the dryer , and the outlet of the dryer is communicated with a production room . the connection between two independent devices may be provided with , as necessary , a conveyer belt , a spiral propeller , an infusion pump , a delivery pipe , a detector or a delivery metering controller , etc . the solid - liquid separator is a centrifugal machine . the feed liquid preparing apparatus is provided with a separator having an ultrafiltration membrane for the separation of the harmful components . the moisture content regulator uses a heating evaporator or a humidifier etc . the room for distributing additional material is a metering distribution system for various additional materials . a process for improving tobacco raw material according to a further embodiment of the invention comprises conducting extraction from tobacco raw material used in cigarette industry by solvent , removing harmful components and backfilling with the feed liquid to obtain the improved tobacco raw material . the process specifically comprises the following steps : 1 ) mixing cut tobacco ( tobacco raw material ) with a mixed solvent containing 80 % of purified water and 20 % of ethanol at a mass ratio of 1 : 17 ( tobacco raw material solvent ), and then conduct an extraction at a temperature of 10 ° c . for 120 minutes ; 2 ) conducting a solid - liquid separation for the tobacco raw material after extraction by means of centrifugation until the dryness of tobacco raw material reaches 60 %; 3 ) using the extract liquor after the solid - liquid separation of the cut tobacco for preparing an extract of natural tobacco that can be used in this process ; 4 ) preparing a backfilling feed liquid by the following steps : firstly , diluting with purified water 1 part by mass of aqueous extract of natural tobacco prepared by the extract liquor in the present process and 0 . 1 part by mass of the alcohol extract of natural tobacco prepared by an extract liquor obtained from other process , mixing them uniformly , and then removing the harmful components by using a combination of a nanofiltration membrane with a cut - off molecular - weight of 2000 dalton and an ultrafiltration membrane with a cut - off molecular - weight of 100000 dalton , and subsequently adding humectant or other functional agents allowed to be added in the tobacco production so as to obtain the backfilling feed liquid with a concentration thereof being controlled by 30 %; 5 ) adjusting the dryness of the tobacco raw material after the solid - liquid separation to 40 %, then backfilling uniformly the backfilling feed liquid into the tobacco raw material after solid - liquid separation by means of immersion , in which the mass ratio of the backfilling is 80 %. 6 ) pre - drying by microwave the tobacco raw material after backfilling until the dryness of the tobacco raw material reaches 60 %, followed by reducing the moisture to 12 % by inflation process , thus obtaining the end product . as shown in fig1 , an apparatus for the process for improving tobacco raw material in the third embodiment is a system composed of a plurality of interconnected independent devices comprising a material room , a solvent room , an extractor , a solid - liquid separator , an extract producer , an extract room , a feed liquid preparing device , a room for collecting harmful substance , a room for distributing additional material , a room for collecting fertilizer raw materials , a moisture content regulator , a feed liquid backfiller and a dryer , wherein the outlet of the material room and the liquid outlet of the solvent room are communicated with the inlet of the extractor , the outlet of the extractor is communicated with the inlet of the solid - liquid separator , the liquid outlet of the solid - liquid separator is communicated at one branch with the liquid inlet of the extract producer and at the other branch with the room for collecting fertilizer raw materials , the outlet of the extract producer is communicated with the inlet of the extract room , the outlet of the solid - liquid separator is communicated at one branch with the inlet of the secondary material room and at the other branch with the inlet of the moisture content regulator , the outlet of the secondary material room is communicated with the inlet of the extractor , the outlet of the moisture content regulator is communicated with the inlet of the feed liquid backfiller , the outlet of the extract room is communicated with the inlet of the feed liquid preparing device , the room for distributing additional material is communicated with the inlet of the feed liquid preparing device , the liquid outlet of the feed liquid preparing device is communicated with the liquid inlet of the feed liquid backfiller , the harmful substance outlet of the feed liquid preparing apparatus is communicated with the room for collecting harmful substance , the outlet of the feed liquid backfiller is communicated with the inlet of the dryer , and the outlet of the dryer is communicated with a production room . the connection between two of the above independent devices may be provided with , as necessary , a conveyer belt , a spiral propeller , an infusion pump , a delivery pipe , a detector or a delivery metering controller , etc . the solid - liquid separator is a centrifugal machine . the feed liquid preparing device is provided with a separator having an ultrafiltration membrane for the separation of the harmful components . the moisture content regulator uses a heating evaporator or a humidifier etc . the room for distributing additional material is a metering distribution system for various additional materials .