| 摘要 |
PROBLEM TO BE SOLVED: To obtain a low-sulfur gas oil having a high lubricity by oxidizing a gas oil fraction contg. at least a specified amt. of naphthalenes with naphthalenes-oxidizing bacteria to thereby bring the sulfur content and alkali extractable content each into a specified range. SOLUTION: Naphthalenes-oxidizing bacteria are planted in a multiplication medium contg. specified amts. of glucose, ammonium sulfate, sodium phosphate hydrate, disodium phosphate heptahydrate, MgCl2 , KCl, FeSO4 , MnCl2 .2H2 O, CaCl2 , and naphthalene and are cultured under specified conditions. The medium is then centrifuged, and the resultant precipitate is suspended in a phosphoric acid buffer soln. to give a bacteria suspension. The suspension is added to a gas oil fraction produced at a petroleum refinery, contg. 0.005mass% naphthalenes represented by the formula (wherein R<1> to R<8> are each H, a 1-8C alkyl, etc.), and having a b.p. of about 150-360 deg.C. The fraction is then put into a container and is shaked at about 30 deg.C for about a day, and a gas oil layer formed is separated. Thus is obtd. a low-sulfur gas oil contg. up to 0.05wt.% sulfur and 0.005-1wt.% alkali extractables. |
