Method for producing 1,3-butadiene

A method for continuously producing 1,3-butadiene from an ethanol feedstock containing ethanol, comprising:

• a gas preparation step of preparing an ethanol-containing gas from the ethanol feedstock;
• a conversion step of converting ethanol in the ethanol-containing gas to 1,3-butadiene in the presence of a catalyst;
• a purification step of purifying a crude gas containing the 1,3-butadiene obtained in the conversion step to obtain a purified 1,3-butadiene, a catalyst regeneration step of regenerating the catalyst through a line different from a line used in the conversion step, and a nitrogen purging step,
• wherein the gas preparation step comprises a step A1 of vaporizing the ethanol feedstock to obtain the ethanol-containing gas under a pressure of −1.0 to 1.0 MPaG and at a temperature of −100 to 200° C.,
• the conversion step uses two or more parallel reactors for at least a part of a conversion reaction of converting ethanol in the ethanol-containing gas to 1,3-butadiene in the presence of the catalyst, while being accompanied by generation of hydrogen,
• the purification step comprises at least one step selected from the group consisting of:
• a step C1 of converting butene in the crude gas into 1,3-butadiene by dehydrogenation reaction, a step C2 of separating hydrogen gas from the crude gas by gas-liquid separation to obtain a 1,3-butadiene-containing liquid, a step C3 of distilling a liquefied product of the crude gas or the 1,3-butadiene-containing liquid to separate the liquefied product or the 1,3-butadiene-containing liquid into an ethylene-containing gas, a 1,3-butadiene-containing effluent, and an acetaldehyde-containing liquid, and a step C4 of distilling the acetaldehyde-containing liquid to separate the acetaldehyde-containing liquid into an acetaldehyde-containing gas and a residual liquid containing water
• the catalyst regeneration step comprises supplying an oxygen-containing gas having an oxygen concentration of 0.01 to 100% by volume to at least one reactor of the two or more parallel reactors, which is different from that or those used in the conversion step, and discharging a carbon dioxide-containing gas from the reactor, to thereby regenerate the catalyst, while continuing the conversion step, and
• the nitrogen purging step comprises supplying nitrogen gas to the reactor after the conversion step, thereby replacing an atmosphere in the reactor with a nitrogen gas atmosphere.