報告書番号

U93015

タイトル（和文）

石炭の生物加工－７－鉄酸化細菌を適用したカラム浮遊選炭による石炭の脱硫

タイトル（英文）

BIOPROCESSING OF COAL-7- DESULFURIZATION OF COAL BY MICROBIAL COLUMN FLOTATION WITH IRON-OXIDIZING BACTERIUM

概要 （図表や脚注は「報告書全文」に掲載しております）

微生物浮遊選炭における脱硫効果の検証とその向上を目指し，鉄酸化細菌のカラム浮遊選炭への適用について検討した。微生物処理により黄鉄鉱硫黄の除去率は増加したが，それにともない石炭の回収率が低下した。しかしながら，ケロシンの添加により，石炭の回収率は増加し，高い脱硫率を得ることができた。また，カラム浮選器の太さと長さの比を改善することにより，ケロシンの添加なしに高い石炭の回収率と脱硫率が得られ，同時に脱硫に要する微生物量も低減できた。この微生物カラム浮遊選炭により，ピッツバーグ炭中に含まれる単体あるいは石炭粒子表面に露出した形態で含まれる黄鉄鉱硫黄が脱硫され石炭の回収率７０％で黄鉄鉱硫黄を２．９％から１．１％まで低減できた。

概要 （英文）

COAL HAS PROMISE AS AN ALTERNATIVE ENERGY SOURCE TO OIL.HOWEVER,COAL COMBUSTION RELEASES SO2 INTO THE ENVIRONMENT ACOST-EFFECTIVE DESULFURIZATION TECHNIQUE IS NEEDED TO USE HIGH-SULFUR COAL.WE HAVE RESEARCHED MICROBIAL FLOTATION USING PYRITE,AND SUGGESTED THAT THE DESULFURIZATION PERIOD CAULD BESHATERED FROM WEEKS BY CONVENTIONAL LEACHING TO MINUTES.AS A NEXT STEP,DESULFURIZATION OF PULVERIZED COAL BY MICROBIAL FLOTATION SHOULD BE PROVED EXPERIMENTALLY. T.FERROOXIDANS T-4 STRAIN WAS APPLIED TO COLUMN FLOTATION TO REMOVE PYRITIC SULFURFROM IMITATION COAL.INCREASED CELL DENSITY IN MICROBIAL FLOTATION RESULTED IN INCREASED REJECTION OF PYRITE,BUT DECREASED COAL RECOVERY.THE ADDITION OF KEROSENE TO THE MICROBIAL FLOTATION INCREASED THE RECOVERY FROM 55% (WITHOUT KEROSENE) TO 80%(WITH 50 MU L/L KEROSENE)WITH A REDUCTION OF THE PYRITIC SULFUR CONTENT FROM 11.5%(FEED COAL)TO 4%(PRODUCT COAL).KEROSENE ADDITION COULD REDUCE THE PYRITIC SULFUR CONTENT BY INCREASING THE COAL RECOVERY.HOWEVER,ADDITION DID NOT ENHANCE SEPARATION OF PYRITE FROM IMITATION COAL.EXCELLENT SEPARATION WAS OBTAINED BY MICROBIAL FLOTATION WITH A LONG COLUMN HAVING A LARGE L/D (LENGTH/DIAMETER)RATIO.MICROBIAL FLOTATION REDUCED THE PYRITIC SULFUR CONTENT FROM 11.5%(FEED COAL)TO 2%(PRODUCT COAL)AND 80% OF THE FEED COAL WAS RECOVERED WITHOUT KEROSENE.A MICROBIAL FLOTATION COLUMN WITH A LARGE L/D RATIO ALSO CUTTHE NUMBER OF CELLS FOR DESULFURIZATION TO LESS THAN 10% OF THE REPORTED ONE. MICROBIAL FLOTATION WITH A LARGE L/D RATIO COLUMN WAS USED TO DESULFURIZE PULVERIZED PITTS BURG COAL.THE COLUMN FLOTATION REJECTED THEPYRITE WHICH WAS WERE LIBERALIZED COMPLETELY OR REMAINED AT THE SURFACE OF COAL PARTICLES.THE PYRITIC SULFUR CONTENT WAS REDUCED FROM 2.9%(FEED COAL)TO 1.%(PRODUCT COAL)WITH 70% RECOVERY.

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