Patent GB-689586-A (GB)
Title: Improvements in or relating to the refining of sulphur-containing mineral oil fractions
IPC: C10L1/06
Filed: 1950-05-25
Abstract: The crude isohexane or isoheptane cut of petroleum is refined by distilling the cut in a column of at least 50 theoretical plate operating equivalence, treating the appropriate distillation fraction (as indicated below) to reduce its sulphur content or to convert chemically the sulphur compounds contained therein, and p  then blending the treated fraction with an appropriate untreated distillation fraction (as indicated below).  In the case of isohexane, the distillation is carried out to remove approximately 20 per cent overhead, and it is this overhead fraction which is subjected to the sulphur-reduction or sulphur-conversion treatment; the treated fraction is blended either with the distillation residue or with an intermediate fraction (obtained from the distillation residue and constituting the bulk thereof).  In the case of isoheptane, the distillation is carried out to remove an intermediate fraction boiling in the range 77-88 DEG  C., and it is this intermediate fraction which is subjected to the sulphur reduction or sulphur-conversion treatment; the treated fraction is blended with the distillation overhead and/or residue fractions. Sulphur-reduction or sulphur conversion treatments mentioned are catalytic hydrogenation, cupric chloride treatment, catalytic desulphurization by splitting off hydrogen sulphide, acid treatment, and extraction, for example by caustic soda in the presence of potassium isobutyrate or alkyl phenols.  In examples: (1) crude isohexane is distilled to remove 20.2 per cent overhead, the overhead fraction is washed with strong sulphuric acid, the residue fraction of the distillation is re-run to remove 95 per cent overhead, and the acid-treated fraction is blended with the 95 per cent overhead; and (2) crude isoheptane is distilled to yield an overhead fraction (boiling range 68-76 DEG  C.), an intermediate fraction (boiling range 77-88 DEG  C.) and a residue fraction (boiling range 89-99 DEG C.), the 77-88 DEG  C. fraction is washed with strong sulphuric acid and then with soda and re-run to remove 90 per cent overhead, and this 90 per cent overhead is blended with the 68-76 DEG  C. and 89-99 DEG  C. fractions.ALSO:The crude isohexane or isoheptane cut of petroleum is refined by distilling the cut in a column of at least 50 theoretical plate operating equivalence, treating the appropriate distillation fraction (as indicated below), to reduce its sulphur content or to convert chemically the sulphur compounds therein (see Group IV(b)), and then blending the treated fraction with an appropriate untreated distillation fraction (as indicated below). In the case of isohexane, the distillation is carried out to remove approximately 20 per cent overhead, and it is this overhead fraction which is subjected to the sulphur-reduction or sulphur-conversion treatment; the treated fraction is blended either with the distillation residue or with an intermediate fraction (obtained from the distillation residue and constituting the bulk thereof).  In the case of isoheptane, the distillation is carried out to remove an intermediate fraction boiling in the range 77-88 DEG C, and it is this intermediate fraction which is subjected to the sulphur-reduction or sulphur-conversion treatment; the treated fraction is blended with the distillation overhead and/or residue fractions.  In examples, (1) crude isohexane is distilled batchwise through a 100 theoretical plate column operated under reflux ratio of 200 : 1 to remove 20.2 per cent overhead, the overhead fraction is washed with strong sulphuric acid, the residue fraction of the distillation is re-run to remove 95 per cent overhead, and the acid-treated fraction is blended with the 95 per cent overhead and (2) crude p  isoheptane is distilled batchwise through a 100 theoretical plate column operated under reflux ratio of 200:1 to yield an overhead fraction (boiling range 68-76 DEG C), an intermediate fraction (boiling range 77-88 DEG C), and a residue fraction (boiling range 89-99 DEG C), the 77-88 DEG C fraction is washed with strong sulphuric acid and then with soda and re-run to remove 90 per cent overhead, and this 90 per cent overhead is blended with the 68-76 DEG C and 89-99 DEG C fractions.