Nippon Shokubai Co., Ltd.

Elf Atochem S.a.

Other

Kazuya Hata

Hirokazu Itoh

Tetsushi Kawamura

Yoshihiro Arita

Toshifumi Hatanaka

Kazuaki Abe

Einosuke Jodo

Yoshiro Arita

Presulfurizing process and presulfurization promoter for a desulfurization catalyst to be used in a hydrodesulfurization unit of petroleum refinery of high molecular hydrocarbons, in which fresh metal oxide in said desulfurization catalyst is sulfurized with hydrogen sulfide produced from sulfur-containing compounds in a feed stream. In the invention, a compound having mercapto alkylthio group: HS&mdash;C,H,&mdash;S&mdash; (in which &ldquo;m&rdquo; is an integer of 2 to 4) is added as promoter at a proportion of 10 ppm to 0.5% by weight and presulfurization is promoted at 180 to 260&deg; C.

Process for presulfurizing a desulfurization catalyst used in a hydrodesulfurization unit of petroleum refinery and presulfurization promoter

Method for improving the yield of lighter components in heat-refining process of petroleum heavy oil, and additive used in the method. The heat-treatment in a heating unit is effected in the presence of at least one compound (I) having at least one mercapto alkylthio group: HS--C.sub.m H.sub.2m --S--, in which 'm' is an integer of 2 to 4.

Method for improving the yield of lighter components in heat-refining

Method for reducing deposition of cokes in heat-refining process of petroleum high-molecular hydrocarbons, characterized in that heat-treatment in a heating unit is effected in the presence of at least one compound (I) having at least one mercaprtoalkylthio group:

Method for reducing deposition of cokes in heat-refining process of

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Tokyo, Japan

Kazuya Hata