報告書番号

U94008

タイトル（和文）

石炭の生物加工９．－微生物浮遊選炭の連続化への基礎的検討－

タイトル（英文）

BIOPROCESSING OF COAL 9. -DESULFURIZATION OFSIMULATED HIGH-SULFUR COAL BY CONTINUOUS COLUMN FLOTATION USING IRON-OXIDIZING BACTERIA-

概要 （図表や脚注は「報告書全文」に掲載しております）

鉄酸化細菌を用いた微生物浮遊選炭の連続化を目的として，本菌の連続大量培養と濾過膜を用いた培養液中の菌体の濃縮について検討し，この菌体の濃縮液を用いた模擬高硫黄炭の連続脱硫を試みた。連続培養により，培養容量１ｍｌあたり１時間に２．０×１０７個の鉄酸化細菌を生産できることがわかった。また，生産した培養液は，１時間の濾過により菌体回収率９０％で細胞濃度を２０倍まで濃縮できた。この菌体濃縮液を用いた微生物浮遊選炭により，１時間安定して１０％の黄鉄鋼を含む模擬高硫黄炭を４％まで連続的に脱硫でき，最終的に７８％の黄鉄鋼除去率で６５％の石炭回収率が得られた。

概要 （英文）

COAL IS EXPECTED TO BE AN ALTERNATIVE ENERGYSOURCE FOR OIL. HOWEVER,COAL CONTAINS SULFUR AND ITS COMBUSTION RELEASES SULFUR DIOXIDE INTO THE ENVIRONMENT CAUSING ACID DEPOSITION. SULFUR-REMOVAL TECHNOLOGY FOR COAL IS READED. WE HAVE DEVELOPED MICROBIAL FLOTATION AS COST-EFFECTIVE DESULFURIZATION TECHNOLOGY. MICROBIAL FLOTATIONIS SUPERIOR TO CONVENTIONAL LEACHING FOR A SHORT DESULFURIZATION PERIOD. HOWEVER,DESULFURIZATION HAS ONLY BEEN PROVED FOR BATCH SYSTEMS AND ACONTINUOUS SYSTEM MUST BE DEVELOPED. DESULFURIZTION OF SIMULATED HIGH-SULFUR COAL BY COLUMN FLOTATION USING T.FERROOXIDANS WAS INVESTIGATED IN A CONTINUOUS SYSTEM. T.FERROOXIDANS (T-4 STRAIN) WAS CULTIVATED BY CONTINUOUS CULTURE IN A 600-ML JAR FERMENTER. THE CULTURE PRODUCED BACTERIA AT THE RATE OF 2.0 107 CELLS/H/ML OF CULTURE MEDIUM FOR 1 MONTH. THE BACTERIA PRODUCED IN 1 DAY BY CONTINUOUS CULTURE CAN REMOVE 58 G OF PYRITE FROM SIMULATED HIGH-SULFUR COAL BY MICROBIAL FLOTATION. THE BACTERIA IN THE CONTINUOUS CULTURE MEDIUM WERE CONCENTRATED BY CROSS-FLOW FILTRATION USING A HOLLOW-FIBER FILTER. THE BACTERIA WERE CONCENTRATED TWENTY TIMES TO DENSITY OF 2.3 109 SELLS/ML IN 1 HOUR 90% RECOVERY. BATCH MICROBIAL FLOTATION WAS USED TO DECIDE THE OPTIMUM CELL DENSITY FORPYRITE REMOVAL. PYRITE REMOVAL INCREASED WITH INCREASED CELLS AND BECAUSE SATURATED AT A CELL DENSITY OF 5.0 108 CELLS/G COAL,WHICH WAS THEOPTIMUM CONDITION. CONTINUOUS MICROBIAL FLOTATION WAS CARRIED OUT AT THE OPTIMUM CELL DENSITY OF 5.0 108 CELLS/G COAL. THE PYRITE CONTENT OF THE FROTH WAS REDUCED CONTINUALLY FROM 10% OF THE FEED TO 4% IN 1 HOUR. AFTER 1 HOUR OF OPERATION,78% OF THE TOTAL ADDED PYRITE IN THE SIMULATED HIGH-SULFUR COAL WAS REMOVED AND 65% OF THE TOTAL ADDED CARBON WASRECOVERED AS FROTH.

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