Spherizone process

Application To produce polypropylene-based polymers, including homopolymer polypropylene, random, heterophasic impact and specialty dual composition copolymers, using Spherizone process technology. 

Description The Spherizone process is Basell s new proprietary gas-loop reactor technology based on a Multi-Zone Circulating Reactor (MZCR) concept. Inside the reactor (1) the growing polymeric granule is continuously recirculating between two interrelated zones, where two distinct and different fluodynamic regimes are realized. 

Despite the success of the Spheripol process, Basell continue research aimed at improving product characteristics, widening the range of grades and developing the next generation of PP technology, the Spherizone process. 

The Spherizone process, using Basell s high yield/high selectivity catalysts, produces spherical polymer particles with an outstanding morphology control directly in the reactor. 

Product-wise, the versatility of the Spherizone process is demonstrated by the high-quality product range that includes all standard polypropylene grades, as well as many unique, special products. One key to this versatility is, as mentioned above, the unique design and operation of the MZCR, which, with a very broad range of feasible process conditions, allows for many kinds of polymer structures as well as intimately mixed polymer compositions to be produced. 

The next scale-up phase was the construction of a IGOktpa reactor that retrofitted the existing, two-loop reactor Spheripol plant with one MZCR (Spherizone process) in Brindisi, Italy (Figure 17.6). The remainder of the plant remained unchanged. Of course, even at that time, there were no counter indications to building an entirely new plant. However, this choice allowed the industrial demonstration of the new technology with the minimum investment cost. 

This industrial demonstration of the Spherizone process prompted commercialization of the technology, which was then made available for licensing to third parties. The development of units with capacities of up to 450 kta, presently under construction, represents a world-scale size for PP plants Spherizone maintains industry cost leadership with the capacity of the Spheripol technology. Up to the end of2007, nine Spherizone licenses, for a total capacity near 3 million ton per year, have been granted. 

The design can be made for homopolymer, random copolymer or heterophasic impact copolymer. The modular structure of the process is such that a Spherizone process plant can be upscaled in successive stages, starting with a basic setup for monomodal operations and later adding the barrier recovery section and a fluid bed gas-phase reactor for the production of bimodal and impact copolymer, respectively. 

Therefore, the Spherizone process can be designed to meet the particular requirements of individual licensees, yet it is flexible enough to be easily expanded to meet future needs as business develops. New entrants to the polypropylene business might want to build a plant producing only homopolymers and random copolymers as these are the least expensive, are easy to operate and their products... 

Figure 17.10 shows the capability, in terms of product characteristics, of the Spherizone process. 

Features of the Spherizone process help to reduce both resource consumption and emissions (Figure 17.11). These include use of high yield, highly stereospecific catalysts, recovery and recycle of umeacted monomers, the absence of undesired byproducts from the reaction and the low energy consumption. Owing to the MZCR concept, in the polymerization section of the process the overall energy consumption may be reduced by 0-30%, depending on the type of polymer produced. 

Basell has recently developed the Spherizone process using the circulating-bed reactor, already depicted in Figure 2.36. Other than the different reactor configuration, the Spherizone process is essentially the same as the Spheripol process. 

The Borstar PP process developed by Borealis can operate at temperatures above the critical temperature of the reaction medium. This process uses a loop reactor and gas-phase reactor in series for the production of homopolymer. Additional gas-phase reactors are required for the production of impact copolymers. The first commercial scale plant using this process started in 2000. Basell has announced the development of the Spherizone process using a recirculating gas-phase reactor (Covezzi paper). The reactor contains two zones that can be operated under different conditions, enabling the production of multiphase specialty copolymers in a single reactor. This reactor was first used in a commercial scale plant in 2002. 

A recent development in this technology is the multizone circulating reactor (MZCR) developed by Basell ( Spherizone process), in which a given polymer particle flows back and forth between two reaction zones of a loop reactor, in each of which the conditions are different... 

Fluidized-bed gas-phase reactor, in Spherizone technology, 20 543-544 Fluidized-bed incinerators, 13 176-177 Fluidized-bed process technology, butane-based, 15 502-504... 

Spherizone A development of the Spheripol process for making polypropylene. A special zone is established in the continuous circulating reactor in which additional monomer or a comonomer can be introduced in order to make polymers with different properties. The copolymers can be monomodal, bimodal, random, or twin-random. Nine licenses had been issued in 2006. 

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