Patent EA-000650-B1 (EA)
Title: Method and system for the treatment of a well stream from an offshore oil field
Inventor: LEGRAID TRYGVE
IPC: C10G2/00
Filed: 1996-09-25
Abstract: 1. A process - for being carried out offshore on a vessel, a platform or other installation - for conversion of a natural gas, especially an associated natural gas, to a synthetic crude oil and/or wax in two stages, wherein (1) the natural gas is converted to a synthesis gas consisting of a mixture of carbon monoxide, hydrogen and carbon dioxide in a synthesis gas unit, and (2) the synthesis gas is converted to a synthetic crude oil and/or wax in a Fischer-Tropsch synthesis, characterized in that the synthesis gas from stage (1) for the carrying out of a Fischer-Tropsch synthesis is introduced, in a slurry consisting of liquid products, finely divided catalyst particles and synthesis gas, into a reaction zone in a slurry bubble column reactor (SBCR reactor) wherein an internal separation of the liquid products from the remaining part of the slurry is effected. 2. A process according to Claim 1, characterized in that the synthesis gas from stage (1), after cooling and separation of water, is introduced into the bottom of the reaction zone in the slurry bubble column reactor, said reaction zone being arranged to accommodate for the slurry consisting of liquid products, finely divided catalyst particles and supplied synthesis gas, and to accomodate for a volume of gas above the slurry phase; that liquid product is separated from the remaining part of the slurry by means of a filtration section including a housing and a filter element which together define a filtrate zone having an outlet for the product filtrate, said filter element being arranged to be in contact with the slurry in the reaction zone; that fluid communication is established between the filtrate zone and the portion of the reaction zone containing the gas volume above the slurry phase; and that a mean pressure differential is established across the filter element. 3. A process according to Claim 1 or 2, characterized in that the conversion of natural gas to a synthesis gas in stage (1) is effected by partial oxidation. 4. A plant for conversion of a natural gas, especially an associated natural gas, to a synthetic crude oil and/or wax in two stages, wherein (1) the natural gas is converted to a synthesis gas consisting of a mixture of carbon monoxide, hydrogen and carbon dioxide in a synthesis gas unit, and (2) the synthesis gas from said unit is converted to a synthetic crude oil and/or wax in a Fischer-Tropsch unit, characterized in that the Fischer-Tropsch unit comprises one or more slurry bubble column reactors (SBCR reactors) each comprising a reactor zone arranged to contain a slurry consisting of liquid products, finely divided catalyst particles and synthesis gas, and in that the reactor(s) is/are arranged for internal separation of liquid products from the remaining part of the slurry. 5. A plant according to Claim 4, characterized in that each slurry bubble column reactor comprises: a vessel defining a reaction zone arranged to accommodate both the slurry phase and a volume of gas above the slurry phase; means for introducing the synthesis gas in the slurry phase in the lower region of the vessel; a filtration section arranged to separate liquid products from the slurry phase, including a housing which at least partially surrounds the vessel, and a filter element which together with said housing defines a filtrate zone having an outlet for the product filtrate, said filter element being arranged to be in contact with the slurry in the slurry zone; means establishing fluid communication between the filtrate zone and that part of the reaction zone which in use is to be occupied by the volume of gas above the slurry phase; and means for establishing a mean pressure differential across the filter element. 6. A plant according to Claim 5, characterized in that it is located on skids which can be secured easily exchangeably to a vessel, an offshore platform or other offshore installation. 7. A plant according to Claim 6, characterized in that it is adapted for installation on a FPSO vessel (FPSO = "Floating Production, Storage and Offloading").