| 摘要 |
PURPOSE:To separate and concentrate carbon dioxide and further reduce it to methane, methanol, etc., and recycle it as fuel by bringing waste gas containing carbon dioxide and sulfur oxide gas into contact with absorbents containing alkaline earth compounds. CONSTITUTION:Waste gas containing sulfur dioxide and dioxide obtained by treating at a denitration device 3, as required, combustion flue gas produced by burning fossil fuel 1 at a boiler 2 is led to an absorption column 10, where the waste gas is contacted with slurry of calcium carbonate as absorbent so that nitrous acid gas and carbon dioxide are absorbed into the absorbent. The gas free from these gases is discharged out of the column 10. The absorption liquid is separated to calcium sulfite, in the form of solid, and a solution of calcium bicarbonate at a solid-liquid separation tank 12, whereby the solution of calcium bicarbonate is sent to a decomposition tank 15 to be decomposed to carbon dioxide and calcium carbonate. The carbon dioxide of high concentration produced at the tank 15 is sent to a reduction column 4, where it is reduced to methane, methanol, etc., using hydrogen produced at a water electrolytic cell 5 by water electrolysis using power of a solar battery 6. |
