報告書番号

U97010

タイトル（和文）

石炭の生物加工－１２－連続石炭脱硫装置の試作とその性能評価

タイトル（英文）

BIOPROCESSING OF COAL-12- -PRELIMINARY CONTINUOUS COLUMN FLOTATION SYSTEM FOR MICROBIAL DESULFURIZATION OF COAL-

概要 （図表や脚注は「報告書全文」に掲載しております）

当所では安価かつ簡便な石炭の燃焼前脱硫法として微生物浮遊選炭法を提案してきた。これまで，回分式の脱硫実験を行ってきたが，今後，実用化を図る際には，石炭の処理量を増大させる必要があるため，脱硫装置の大型化および連続化が不可欠となる。今回，連続石炭脱硫装置（培養槽５０Ｌ，カラム浮選機内径８ｃｍ，高さ１．５ｍ）を試作し，模擬高硫黄炭と高硫黄炭（原炭）の連続脱硫実験を行った。その結果，模擬炭を用いた場合，微生物無添加では，精炭中の全硫黄分は約７％に止まるのに対し，微生物を添加することにより，全硫黄を約１％に低減することができた。また高硫黄炭として，Ｐｉｔｔｓｂｕｒｇ炭（黄鉄鉱硫黄分：２．９９ｗｔ％）を用いて，連続脱硫実験を行った結果，微生物を添加することにより，１時間に渡り硫黄分１％の精炭を安定して連続的に得ることができた。その際の可燃分回収率は８０％程度であった。

概要 （英文）

COAL COMBUSTION RELEASES SULFUR DIOXIDE INTOTHE ENVIRONMENT. TO SOLVE THIS PROBLEM, WE HAVE BEEN DEVELOPING A MICROBIAL FLOTATION TECHNIQUE FOR DESULFURIZING COAL. IN CONVENTIONAL FLOTATION, REMOVAL OF PYRITIC SULFUR IN COAL WAS IMPOSSIBLE, BECAUSE THE SURFACE PROPERTIES OF PYRITE AS WELL AS COAL ARE HYDROPHOBIC. ON THE OTHERHAND, MICROBIAL FLOTATION CAN REMOVE THE PYRITE BY CHANGING THE SURFACE PROPERTIES OF PYRITE BY BACTERIAL ADHESION. WE HAVE DEVELOPED A FLOTATION BATCH SYSTEM SO FAR. THIS REPORT INVESTIGATES A CONTINUOUS DESULFURIZATION SYSTEM. WE CONSTRUCTED EXPERIMENTAL FACILITIES FOR CONTINUOUS MICROBIAL DESULFURIZATION OF COAL, COMPRISING A CULTIVATION JAR FERMENTER (WORKING VOLUME 50 L) AND COLUMN FLOTATION EQUIPMENT (RADIUS 8 CM, HEIGHT 1.5 M). THE REMOVAL OF PYRITIC SULFUR FROM HIGH-SULFUR IMITATION COAL AND RAW COAL WERE INVESTIGATED AS FOLLOWS: (1)THIOBACILLUS FERROOXIDANS WAS CULTIVATED IN CONTINUOUS CULTURE AT A RATE OF 1.8 **11 CELLS/H FOR 20 DAYS WITHOUT PRODUCTION OF JAROSITE PRECIPITATE. (2)DESULFURIZATION OF HIGH-SULFUR IMITATION COAL WAS PERFORMED IN THIS CONTINUOUS MICROBIAL COLUMN FLOTATION SYSTEM. 4.4 10**9 CELLS/G-COAL WAS ADDED TO THE FLOTATION COLUMN; THE SULFUR CONTENT WAS REDUCED FROM 10.1% IN THE FEED TO 1.2% IN THE FROTH. THE COMBUSTIBLE RECOVERY WAS ABOUT 85%. (3)FOR RAW HIGH-SULFUR COAL, THE SULFUR CONTENT WAS REDUCED FROM 2.99% IN THE FEED TO 1.2% IN THE FROTH BY ADDITION OF 7.7 10**9 CELLS/G-COAL. THE COMBUSTIBLE RECOVERY WAS ABOUT 80%. THESE RESULTS SHOW THAT THIS CONTINUOUS FLOTATION SYSTEM WORKS EFFECTIVELY.

報告者

キーワード