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In this page you will find free data about Polypropylene, including:
- What is Polypropylene
- How to make Polypropylene
- Polypropylene uses and applications
This page presents brief synopsis of Polypropylene production technology, describing, in a concise way, relevant technical and economic aspects. Each manufacturing process description will consist of:
- Major process steps
- Simplified, schematic flow diagram & key equipment
- Important safety or environmental considerations
- Economic perspective, comprising capital expenditures and/or operating expenses
Polypropylene Manufacture via Gas-Phase Technology (Fluidized-Bed Reactor)
Polypropylene (PP) is one of the world’s most widely used polymers, second only to polyethylene in terms of global demand. The global market for polypropylene is over 60 million metric tons per year, and it is utilized in a broad and diverse range of end-uses — from injection-molding applications to films and sheets, as well as synthetic raffia and other fibers, among others. Traditionally, the most representative types of propylene polymerization are the following: hydrocarbon slurry or suspension, bulk (or bulk slurry), gas phase and hybrid (uses bulk- and gas-phase polymerization reactors).
The Unipol PP process, a leading gas-phase process technology, was recently offered for sale by Dow Chemical Co. (Midland, Mich.; www.dow.com). The company is looking to focus on high-margin areas, and is seeking buyers for its polypropylene licensing and catalyst business.
PP is a thermoplastic material formed by the polymerization of propylene, resulting in a macromolecule that contains from 10,000 to 20,000 monomer units. The production of a polypropylene homopolymer via a gas-phase process similar to Dow Unipol is depicted in the flowsheet. The process shown is capable of producting homopolymer and random copolymer PP. For impact copolymer production, a secondary reaction loop is required. In this process, gaseous propylene contacts a solid catalyst in a fluidized-bed reactor. The process can be separated into three different areas: purification and reaction; resin degassing and pelletizing; and vent recovery.
Purification and Reaction
Fresh polymer grade (PG) propylene is sent to fixed-bed dryers to remove water and other polar impurities. The purified propylene, a recycle stream from the vent recovery system and comonomers (in case of copolymer production) are then fed continuously to the reactor. A gas compressor circulates reaction gas upward through the reactor, providing the agitation required for fluidization, backmixing and heat removal. No mechanical stirrers or agitators are required in the process reactor. The overhead gas from the reactor passes through a cooler for reaction heat removal. Catalyst is continuously fed to the reactor.
Resin Degassing and Pelletizing
Resulting granular polypropylene is removed from ...
An economic evaluation of the process was conducted for ...
Polypropylene Manufacture via Bulk-Phase Technology
Polypropylene (PP) is a thermoplastic polymer formed by the polymerization of 10,000–20,000 monomers of propylene. With a global market of about 60 million metric tons per year, PP is the second most-used polymer globally.
More than 35% of the world’s total PP is produced using LyondellBasell’s (Houston; www.lyondellbasell.com) Spheripol technology.
In Spheripol technology, polymerization is carried out in liquid propylene (a bulk-slurry process) in tubular loop reactors. This type of reactor has a high heat-removal capacity and avoids polymer deposition on reactor walls.
A polypropylene homopolymer production process via a bulk-slurry process similar to LyondellBasell Spheripol is depicted in the flowsheet. The process shown is capable of producing both homopolymer and random copolymer PP. For impact copolymer production, the addition of a gas-phase reactor is required. In this process, liquid propylene contacts a solid catalyst inside a loop reactor. The process can be separated into three main areas: purification and reaction; polymer degassing and pelletizing; and monomer recovery.
Reaction and Purification
In this stage, fresh polymer grade ...
Polypropylene Manufacture via Gas-Phase Technology (Stirred-Bed Reactor)
Since 1956, polypropylene has been commercially produced using catalysts and technology that were developed from independent research by Karl Ziegler and Giulio Natta. Their namesake catalysts have enabled the widespread use of this polymer in the decades since. Polypropylene has become a major part of the modern plastics-resin market because of its unique physical properties, and is now employed in a wide range of applications from food packaging to automotive plastics.
Historically, polypropylene has been produced at industrial scale by three main polymerization approaches: hydrocarbon slurry or suspension processes, bulk-phase processes and gas-phase processes. Two leading technologies for gas-phase polypropylene production are Unipol, a fluidized-bed reactor process offered by the Dow Chemical Co. (Midland, Mich.; www.dow.com), and Novolen, a stirred-bed reactor process developed by Lummus Novolen, now a part of Chicago Bridge and Iron Co. N.V. (The Hague, The Netherlands; www.cbi.com). Here, the flowsheet depicts a gas-phase process similar to Lummus Novolen’s stirred-bed reactor technology.
Propylene conversion to polypropylene is achieved through the use of a Ziegler-Natta catalyst. This process occurs in a continuous vertical stirred reactor at mild temperatures (about 80°C). The overall yields are typically >99 wt.%. The process can be divided in three main areas: purification and reaction; resin degassing and pelletizing; and vent recovery.
Purification and Reaction
The polymerization catalysts are sensitive to several ...