SBR

Factory for the production of synthetic rubber in Elemir near Zrenjanin began to work in late 1983, and since 1991 it has been a part of HIP-Petrohemija. The factory consists of three production plants.

Production of 1,3-butadiene, has been licensed by Nippon Zeon (Japan), and the designed capacity is 45,000 tons per year. Secondary product is raffinate-1 (butane-butene fraction). By the physical-chemical process of two-stage extractive rectification 1,3-butadiene of high purity (99.5% min) is obtained. C4 fraction from ethylene facilities is used as raw material.Extractive solvent is dimethylformamide (DMF). In the first section of the extractive distillation, C4 fraction is separated into two streams, of which one contains butanes and butenes which are less soluble in the solvent, while the other contains butadiene and acetylene, which are more soluble. Stream of butadiene and acetylene is suppressed into the second section of extractive distillation where separation into crude butadiene and acetylene is performed. Crude butadiene passes to the fractional distillation section, where purifying treatment is carried out to obtain the appropriate product purity. Butadieneas a final product is then transported by the pipelines into the storage tank or directly into the plant for the production of SBR. Stream of butane and butene produced by separation in the first section is, after separation of C3 components, as a secondary product raffinate-1 transported by pipelines into storage tanks and then used for the production of MTBE.

Butadieneis mainly used in the production of synthetic polymers such as synthetic rubber (SBR, polybutadiene rubber, nitrile rubber, neoprene, etc.), then thermoplastic (ABS acrylonitrile butadiene styrene, which is used in the electronic and automobile industry) and latex (styrene-butadiene copolymer latex, used in paper and carpet industry, etc.).

Licensor of this unit is Bunawerke Huls, Germany, and the project was developed by Lurgi, also from Germany. The product is emulsion styrene-butadiene rubber (SBR), with the annual capacity of 40.000 tons. Three different types of SBR are produced under the trade name HIPREN ®, as two types of series 1500 and one type of series 1700. SBR is obtained by low-temperature reaction of copolymerization of styrene and butadiene which takes place in water emulsion in the presence of initiators and modifiers. After necessary chemical preparations and cooling, reactants are continuously introduced into the first polymerization reactor. The reaction takes place in a series of eight serially connected flow reactors. Depending on the type of rubber that is produced, two types of emulsifiers are used. One is on the basis of resin soap, and the other on a mixture of fatty acids and resin soap. Reaction is stopped by addition of stopper at the desired degree of monomer conversion (about 60%). As an intermediate product latex is obtained, stable colloidal dispersion of polymer in water with non-reacted monomers.

By regeneration from latex, non--reacted butadiene latex and styrene are separated, which are re-used in the polymerization process. The resulting synthetic rubber is washed with water, dried and baled. Rubber bales are wrapped into a polyethylene foil and packed in wooden box palletes.

Emulsion SBR is broadly applied. Depending on the type of rubber, it is used in the production of car and truck tires, footwear, flooring, adhesives, hoses, conveyor belts, technical equipment of high hardness and other.

License and project are from the company Snam Progetti from Italy. The main product is methyl tertiary-butyl ether (MTBE), and the annual capacity is 35.000 tons. Secondary product is raffinate-2.
MTBE is obtained by catalytic reaction of esterification of isobutene (from raffinate-1) with methanol. The process takes place in two flow tube reactors, where in the first reactor the most of the reaction is done, while the other has only a final function. In the reactor, strictly selective catalyst is used which enables the reaction to be carried out only between isobutene and methanol, while other hydrocarbons go easily through the reactors. Obtained MTBE and non-reacted hydrocarbons are introduced into the distillation column where their separation is performed and MTBE is drained from the bottom of the column, and raffinate-2 (mixture of butene and butane) from the top of the column. As final products, they are transported by pipelines into the storage tanks.
MTBE is used as an additive for motor gasoline and raffinate-2 as an energy source or a very valuable petrochemical feedstock for further processing.