Abstract:
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 m2/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° C. at a pressure of 0.1-0.9 MPa, with an HSV of 0.05-10 h−1, and a H2/naphthalene ratio of 0.1-1.3 mole/mole. The effluent, freed of H2S, NH3 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.
Abstract:
A slurry hydroprocessing process for upgrading a hydrocarbon feedstock containing nitrogen and sulfur using bulk multimetallic catalyst comprised of at least one Group VIII non-noble metal and at least two Group VIB metals wherein the ratio of Group VIB metal to Group VIII metal is about 10:1 to about 1:10.
Abstract:
A process is described that can limit pressure drops during a catalytic hydrotreatment process carried out in a fixed bed reactor. The liquid feed and gaseous reactant are injected into the reactor either side of the bed and flow as a counter-current. Pressure drops are limited by homogeneously mixing solid catalytic and/or inert particles of different diameters in the bed.