Institut Francais Du Pe'trole

Michel Bloch

Jean Cosyns

Slavik Kasztelan

Samuel Mignard

Ren&eacute; Genin

Guena&euml;l Drouglazet

The invention concerns a process for purifying naphthalene. The process comprises selective hydrotreatment corresponding to hydrodesulphuration and/or hydrodenitrogenation and/or hydrodehydroxylation and/or hydrogenation of olefins while limiting naphthalene hydrogenation. The catalyst used comprises a matrix, at least one group VIII metal, at least one group VI metal and optionally phosphorous. It has a specific surface area of at most 220 m,/g, a pore volume of 0.35-0.7 ml/g and an average pore diameter of over 10 nm. The process is carried out at 150-325&deg; C. at a pressure of 0.1-0.9 MPa, with an HSV of 0.05-10 h,, and a H,/naphthalene ratio of 0.1-1.3 mole/mole. The effluent, freed of H,S, NH,and water, undergoes a naphthalene separation process by distillation or, as is preferable, by crystallisation. Further, recycling the separated tetralin to the hydrotreatment step can substantially increase the naphthalene yield. In this case, the tetralin/naphthalene ratio at the reactor inlet is in the range 0.005 to 0.08.

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Rueil-Malmaison, France

Michel Bloch