Butanediol Production from Acetylene

The process under analysis comprises three major sections: (1) Addition; (2) Hydrogenation; and (3) Purification.

Addition. Formaldehyde, pressurized acetylene, and caustic soda are fed to the Addition Reactor, along with catalyst and product streams recovered downstream, yielding a butynediol solution. The reactor effluent passes through a catalyst recovery area and then routed to a butynediol column to remove impurities. The bottom stream, containing butynediol, is sent to the hydrogenation section.

Hydrogenation. The butynediol solution is then fed to a fixed bed reactor, along with a pressurized hydrogen stream, where the main hydrogenation takes place, generating Butanediol. This reactor operates in hydrogen cycle gas mode. The unconverted butynediol is hydrogenated in another fixed-bed reactor, operating at slightly higher temperatures and without recirculating hydrogen. The reactor effluent is separated in a liquid stream, which is sent to a distillation train downstream, and a gas stream, comprising predominantly hydrogen, which is partly recycled, and partly disposed as off-gas.

Purification. In the first column of the distillation train, low boilers compounds are removed as overheads and discharged as waste. The bottom stream is directed to a drying column to remove water from the top and Butanediol as a bottom stream. The bottom is sent to a heavy ends removal, from where the top stream is sent to Butanediol purification, which generates a side stream of purified Butanediol that is sent to storage.