Plant #1 > PP
The PP plant produces PP (polymer polypropylene) by polymerizing the propylene separated in the naphtha cracking plant as raw material using a catalyst. PP has wide applications in our lives such as for industrial film, fishing net, injection moldings for automobiles, and general packaging material. The SPP plant, which began its commercial production in January 1988, has adopted the SPHERIPOL process of Italy’s MONTELL (currently known as BASELL) Corporation with its intensive characteristics displaying the transference of polymer by propylene as raw material without separate solvent and using highly active catalysts. Special grades are produced, such as random copolymer and random terpolymer with technology that is superior to that of other companies. Commencing commercial production in December 2001, the 3PP plant has introduced MCI Corporation’s HYPOL-II process, which produces the same grade as SPP. The integrated device loop reactor is the world’s largest. With the production of block copolymers with ethylene content of 6, 8, and 12%, the plant has been recognized for its excellent technological capability with improved operating skills. The PP4 plant, which began commercial production in May 2012, was built with LOTTE Chemical’s own technology and is currently engaged in the licensing business. It has an annual production capacity of 300 thousand tons and Homo and Random Grade are its main products.
■ Production process
01 Catalyst Making Process
The solid powdery catalyst is made from the catalyst mud together with a mixture of grease and oil and is transferred to the pre-contacting pot with promoter TAEL/DONOR. The liquid additive ‘Atmer’ is injected into the 2nd loop reactor discharge when starting up and shutting down the loop reactor to prevent plugging and when producing high-impact copolymers.
02 Integrated Process
The catalyst compound forms an active site in the precontacting pot and performs preliminary integration in the pre-poly reactor R-1200. The preliminarily integrated catalyst is transferred to the loop reactor (R-1201/R-1202) connected in series. To each reactor, PL monomer is continuously supplied to maintain constant solid concentration. HG is supplied to adjust the molecular weight of the polymer. To produce a range of products (random copolymers), PL, EL, and BU, are supplied to the reactor at the proper ratio and the heat of reaction generated at this time is eliminated by Jacket Circulation Water.
03 Monomer Separation and Recovery Process
The polymer slurry is sent to the flash drum, the first degassing sector, through a pipe line jacketed with steam to evaporate the monomer, and the PL gas coming from the flash drum is recycled for resupply to the reactor. When producing homo polymer, random copolymer, and random terpolymer, the polymer and the gas at the flash drum bottom are transferred to the recycled gas filter at 0.5 Kg/cm2.
04 Gas Integration Process
In producing a high-impact copolymer, the homopolymer at the flash drum bottom is transferred to the gas phase reactor; and in the reactor filled with EL/PL gas, it is bonded to the EL-PL rubber to produce impact-resistant polymer.
05 Granulation and Packaging Process
The powder issued from the dryer is mixed with a stabilizer, fed into the extruder to make pellets, and melted, extruded, and hydro-cut in the extruder before being made into the final PP pellets. The PP pellets are transferred to the storage silo, blended for uniform physical properties, packed, and forwarded to the automated warehouse.
