NOVELTY - Production of food-level liquid carbon dioxide comprises mixing carbon dioxide raw gas containing impurity with excess oxygen; heating and desorbing impurity; removing water from resurgent airflow or airflow returned from purifying process; sequentially compressing at 0.1-0.35 MPa, 0.8-1.2 MPa, and 2.3-2.8 MPa, respectively; desulfurizing carbon dioxide raw gas containing impurity with excess oxygen; and reacting methane and ethylene with excess oxygen at 480-520 degrees C and 2.3-2.8 MPa, with palladium and molybdenum as active components and alumina catalyst as carrier.    USE - Production of food-level liquid carbon dioxide used for recycling resurgent gases.    ADVANTAGE - The method reduces methane and ethylene contents of product, i.e. lower than international standard. It allows recovery of regeneration gas from purification tower, such that utilization rate of carbon dioxide raw gas with impurity is improved from 76% to 88%. It increases yield of food-level liquid carbon dioxide product, reduces production cost, and reduces discharge of greenhouse gas.    DETAILED DESCRIPTION - Production of food-level liquid carbon dioxide comprises mixing carbon dioxide raw gas containing impurity with excess oxygen; heating absorbent;, heating and desorbing impurity; removing mechanical water from resurgent airflow or airflow returned from purifying process by water separator; compressing at 0.1-0.35 MPa by first stage compressor; compressing at 0.8-1.2 MPa by secondary compressor; compressing at 2.3-2.8 MPa by third compressor; sending to desulfurizing process; desulfurizing carbon dioxide raw gas containing impurity with excess oxygen; chemically reacting methane and ethylene in impurity and excess oxygen at 480-520 degrees C and 2.3-2.8 MPa, with active components as palladium and molybdenum and carrier as alumina catalyst; generating carbon dioxide and water; removing methane and ethylene in carbon dioxide gas containing impurities; using temperature swing adsorption process, switching work of several purifiers, when certain or several purifiers are at absorbing state, and other purifiers are at reproduction state; absorbing impurities at normal temperature; desorbing impurities at high temperature; selectively absorbing ppm-level micro vapor and ppb-level micro benzene; purifying carbon dioxide gas containing impurity; sending to liquefying, distilling and purifying process, in which heating and desorption of impurities comprises heating adsorbent, heating and desorbing impurity absorbed by adsorbent, cooling adsorbent by airflow and returning it to carbon dioxide raw gas; liquefying carbon dioxide gas containing impurity; sending it together with uncondensed carbon dioxide gas and micro methane, ethylene and oxygen to distilling and purifying step; putting carbon dioxide containing uncondensed carbon dioxide gas and micro methane, ethylene and oxygen to distilling and purifying tower for distilling and purifying; and distilling methane, ethylene and oxygen and uncondensed carbon dioxide gas as flash vapor to obtain liquid carbon dioxide at lower part of tower.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of a process for producing food-level liquid carbon dioxide.