Abstract: A CO2 separation/recover method in cement production exhaust gas has a step of harmful component removal that removes an acidic component and a harmful component from exhaust gas discharged from a cement production facility; and a step of CO2 separation and recover that separates and recovers CO2 by bringing the exhaust gas from which the acidic component and the harmful component are removed into contact with a CO2 absorption material, so that the acidic component and the harmful component are removed before separating and recovering CO2, resulting in deterioration of the absorbing ability of the CO2 absorption material being suppressed; and the cement production exhaust gas can be appropriately disposed.

Abstract: Generating methane by adding hydrogen to CO2 in exhaust gas discharged a from cement production facility or CO2 that is separated and recovered from the exhaust gas, and using the methane as an alternative fuel to fossil fuel such as coal, petroleum, natural gas and the like, by methanation of CO2 in the exhaust gas from the cement production facility that includes exhaust gas originated from lime stone not from the fossil oil and effectively utilizing it, it is possible to reduce usage of the fossil fuel, suppress CO2 originated from energy, and improve an effect of reducing greenhouse gas.