NOVELTY - Methanol production system of liquefied natural gas (LNG)-floating production storage and offloading (FPSO) or floating liquefied natural gas facility (FLNG) comprises an injection separator installed on top of LNG-FPSO or FLNG for separating natural gas mined from offshore oil into three phases, a methanol reactor for supplying gas and synthesizing methanol by catalytic reaction of carbon dioxide and methane, a methanol storage tank for storing and supplying synthesized methanol, and a membrane installed downstream of reactor for removing hydrogen and carbon monoxide.    USE - Used as methanol production system.    ADVANTAGE - The system maintains methanol in liquid state at room temperature, is economical, produces methanol as raw material for energy and chemical processes, and reduces production of LNG and carbon dioxide emissions.    DETAILED DESCRIPTION - Methanol production system of liquefied natural gas (LNG)-floating production storage and offloading (FPSO) or floating liquefied natural gas facility (FLNG) comprises an injection separator (1) installed on the upper side of LNG-FPSO or FLNG for supplying and separating the natural gas mined from the offshore oil into three phases, a methanol reactor (2) for supplying the gas separated from the injection separator and synthesizing methanol through catalytic reaction of carbon dioxide and methane contained in the gas, a methanol storage tank (3) for storing and supplying methanol synthesized from the reactor, and a membrane (4) installed downstream of the reactor for removing hydrogen and carbon monoxide contained in the gas and supplying gas from the reactor. The hydrogen and carbon monoxide removed gas is supplied into the LNG production system. An INDEPENDENT CLAIM is also included for producing methanol of LNG-FPSO or FLNG, comprising (a) separating the natural gas mined from the offshore oil into three phases, (b) synthesizing methanol by catalytic reaction of methane and carbon dioxide contained in the separated gas, (c) storing the synthesized methanol, (d) removing by separating hydrogen and carbon monoxide contained in the gas by using the membrane, and (e) producing LNG from hydrogen and carbon monoxide removed gas.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the methanol production system of FLNG.    Injection separator (1)    Methanol reactor (2)    Methanol storage tank (3)    Membrane (4)    Amine processing unit (5)