Emulsion Styrene Butadiene Rubber Production

The process under analysis comprises three major sections: (1) Polymerization; (2) Monomers recovery; and (3) Coagulation,drying and finishing.

Polymerization. Styrene and butadiene are mixed with emulsifier and demineralized water to form the emulsion that will be fed to the polymerization. Polymerization is comprised of jackted CSTR-type reactors connected in series. To keep the low reaction temperature, all reactors are cooled using ammonia refrigeration. Downstream, a shortstop agent is mixed with the emulsion in order to stop reaction at the desired conversion, avoiding gel formation. The shortstopped latex is sent to monomers recovery section.

Monomers recovery. The latex generated in polymerization reactors is directed to blow down tanks and subsequently flashed to recover unreacted butadiene. Residual butadiene vapors are sent to a butadiene recovery step, while the degassed latex is pumped to a steam stripping column. In butadiene recovery, water is removed from the stream and recovered butadiene is recycled to the Butadiene Plant for butenes separation, so the recovered butadiene can be reused in the eSBR plant. In the steam stripping column, residual styrene monomer is stripped by contacting the latex with steam entering the column bottom. Stripped styrene is recycled to the polymerization, while the latex is transferred to the coagulation.

Coagulation, drying and finishing. In the coagulation step, the latex coagulates and becomes small crumbs suspended in water. The coagulated crumb is then dried in continuous belt dryers. After drying, the rubber is pressed into bales, weighted, film-wrapped, and boxed.