Patent ID: 8404888

Claim:
A process for producing acrylic acid from propane as the starting material, characterized by comprising the following steps (a)-(f): (a) an oxidative dehydrogenation step of passing a gaseous starting mixture containing propane and molecular oxygen through a propylene synthesis zone to form a first flow containing propylene, wherein the supply source of the molecular oxygen has an oxygen concentration higher than 21% by volume; (b) a first oxidation step of passing the first flow through an acrolein synthesis zone to form a second flow containing acrolein; (c) a second oxidation step of passing the second flow through an acrylic acid synthesis zone to form a third flow containing acrylic acid; (d) an acrylic acid recovery step of separating the third flow to a liquid flow containing acrylic acid and a gaseous fourth flow containing unreacted propane and carbon dioxide; (e) a carbon dioxide-removing step of selectively eliminating at least a part of the carbon dioxide from the fourth flow to form a fifth flow containing unreacted propane; and (f) a recycling step of re-using at least a part of the fifth flow as a recycling gas.