Institut Francais Du Pe'trole

Befs Prokem S.a.

Ren&eacute; Genin

Guena&euml;l Drouglazet

Jean Cosyns

Slavik Kasztelan

Samuel Mignard

Edouard Schwartzman

Michel Bloch

The present invention pertains to a process for the purification of an organic product by fractionated crystallization, characterized in that the organic product is purified by circulation in filled tubes by varying the circulation rate at each purification and concentration stage. The invention also pertains to an apparatus for the purification of an organic product by fractionated crystallization designed for the implementation of said process.

Process for the purification of organic products by fractionated crystallization at a variable circulation rate

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.

Process for purifying naphthalene by selective hydrotreatment followed by separation

Growing community of inventors

Mulhouse, France

René Genin

Growing community of inventors

Mulhouse, France

Ren&eacute; Genin

René Genin