# US 6,294,498 B1 · Protection of catalysts by deposition of a protective layer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,294,498 B1 - Document ID: US6294498B1 - Status: Granted - Kind: B1 - Application number: 09/132,517 - Filed: 1998-08-11 - Granted: 2001-09-25 - Earliest claimed: 1997-08-11 - Assignees: Europeenne de Retraitement de Catalyseurs Eurecat - Inventors: Joan Darcissac; Franck Labruyere; Nilanjan Brahma; Pierre Dufrense - Web page: https://patentgrep.com/patent/US6294498B1 ## CPC - B01J 23/888: Tungsten - B01J 23/882: and cobalt - B01J 23/883: and nickel - B01J 33/00: Protection of catalysts, e.g. by coating - B01J 37/0219: {the coating containing organic compounds} - B01J 37/20: Sulfiding - C10G 49/02: characterised by the catalyst used - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES ## Abstract Process for passivation of a heterogenous catalyst of refining reactions or hydrocarbon hydroconversion reactions, characterized in that the external surface of the particles of said heterogeneous catalyst is coated with a protective layer that is made of a particularly inert material which can be eliminated in the reaction zone under the conditions of the reaction. ## Claims ### Claim 1 A process comprising: a) providing an inert coating material capable of functioning as a protective layer against oxygen and water and also being removable during refining or a hydrocarbon conversion reaction; b) applying said coating material on heterogeneous porous hydrocarbon conversion catalyst particles, said catalyst comprising a support and a pair of catalyst metals selected from the group consisting of CoMo, NiMo and NiW under conditions wherein the coating material is present in a quantity corresponding to less than about half of the catalyst pore volume; c) wherein said coating material is 1. atomized or dispersed on the catalyst by continuously stirring the catalyst and keeping it at a temperature that is below the crystallization point of the coating material, or 2. a solution that contains the material is atomized, sprayed or dispersed by continuously stirring the catalyst at a temperature that is above the boiling point of the solvent of said solution; and d) wherein the coating on the particle exhibits a concentration gradient which decreases from the periphery of the particle towards the center of the particle. ### Claim 2 (depends on 1) A process according to claim 1, further comprising eliminating the inert coating material in a reaction zone under the conditions of a refining or hydroconversion reaction. ### Claim 3 (depends on 1) A process according to claim 1, the inert coating material is a natural or synthetic petroleum. ### Claim 4 (depends on 3) A process according to claim 3, wherein the coating material is selected from the group consisting of paraffins, waxes, heavy hydrocarbons, lubricating bases, light polymers, resins, acrylic esters; polyvinyl acetate, copolymers. ### Claim 5 (depends on 1) A process according to claim 1, wherein the inert coating material is a vegetable or animal fat, or a sugar or polysaccharide, used alone or in combination, or diluted in a solvent. ### Claim 6 (depends on 1) A process according to claim 1, wherein inert coating material is in the form of a dilute solution or suspension in a solvent, the inert coating material having a molecular size larger than 10 nm. ### Claim 7 (depends on 1) A passivated catalyst produced according to the process of claim 1. ### Claim 8 (depends on 6) A process according to claim 6, wherein the molecular size is larger than 100 nm. ### Claim 9 (depends on 1) A process according to claim 1, wherein the coating material is polyethylene wax. ### Claim 10 (depends on 1) A process according to claim 1, wherein the coating material is in the form of a solution of an acrylic polymer in ethyl acetate and the coating is applied by spraying the solution onto the catalyst under conditions wherein the solvent is essentially completely vaporized prior to reaching the particles of catalysts. ### Claim 11 (depends on 1) A process according to claim 1, wherein the inert coating material is a polyethylene wax. ### Claim 12 (depends on 1) A process according to claim 1, wherein the inert coating material is an oil and said oil is applied by spraying under an inert atmosphere. ### Claim 13 (depends on 1) A process according to claim 1, wherein the support is alumina. ### Claim 14 (depends on 1) A process according to claim 1, wherein the coating material is in the form of a compound selected from the group consisting of solution of an acrylic polymer in ethyl acetate, a polyethylene wax, and an oil applied by spraying under an inert atmosphere. ### Claim 15 A process comprising: a) providing an inert coating material capable of functioning as a protective layer against oxygen and water and also being removable during refining or a hydrocarbon conversion reaction; b) applying said coating material on heterogeneous porous hydrocarbon conversion catalyst particles, said catalyst comprising a support and a pair of catalyst metals selected from the group consisting of CoMo, NiMo and NiW under conditions wherein the coating material is present in a quantity corresponding to less than 30% by weight relative to the catalyst; c) wherein said coating material is 1. atomized or dispersed on the catalyst by continuously stirring the catalyst and keeping it at a temperature that is below the crystallization point of the coating material, or 2. a solution that contains the material is atomized, sprayed or dispersed by continuously stirring the catalyst at a temperature that is above the boiling point of the solvent of said solution; and d) wherein the coating on the particle exhibits a concentration gradient which decreases from the periphery of the particle towards the center of the particle. ### Claim 16 (depends on 15) A process according to claim 15, wherein a coating material is applied to the catalyst particles at a quantity corresponding to less than 25% by weight relative to the catalyst. ### Claim 17 (depends on 1) A process according to claim 1, wherein said coating material is a paraffin and is applied by heating the catalyst at a temperature below the crystallization of the paraffin and then atomizing the paraffin onto the catalyst whereby the paraffin crystallizes upon contact with the catalyst. ### Claim 18 (depends on 1) A process according to claim 1, wherein said coating material is a polyethylene wax and is applied by heating the catalyst at a temperature below the crystallization of the polyethylene wax and then atomizing the polyethylene wax onto the catalyst whereby the polyethylene wax crystallizes upon contact with the catalyst. ### Claim 19 (depends on 1) A process according to claim 1, wherein said coating material is a liquid heavy hydrocarbon which is applied by atomization whereby the temperature of the catalyst causes the viscosity of the liquid heavy hydrocarbon to increase thereby slowing transport of the coating material into the core of the catalyst. ### Claim 20 (depends on 1) A process according to claim 1, wherein the coating material is applied by diluting or suspending the coating material in a solvent to form a solution or a suspension, applying the resultant solution or suspension onto the catalyst by atomization, spraying or dispersion at a temperature greater than the boiling point of the solvent, whereby the solvent is eliminated by vaporization upon contact with the catalyst. ### Claim 21 (depends on 9) A process according to claim 9 wherein the polyethylene wax is atomized onto the catalyst.