Processes overview

The process of producing polystyrene requires one reactor or a series of reactors controlled by a set of parameters such as temperature, pressure, and conversion rate. The process requires the addition of several raw materials, i.e. solvent, initiator (optional), and chain transfer agents, into the reactors under well-defined conditions. The reaction heat is removed by transfer to the new incoming feed and/or by the evaporation of solvent and/or by heat transfer medium, i.e. circulating oil. 

The crude product coming out of the reactor train has a solid content of between 60 and 90 %. To remove the unconverted monomer and solvent from the crude product, it is heated to about 220 - 260 °C and led through a high vacuum. This is called the devolatilisation step and can have one or two stages. Finally, the cleaned, high purity pol5mier is granulated. The monomer and solvent are stripped in the devolatilisation section and recycled within the process. 

When styrene is polymerised, polyst5rene is formed. The polymerisation of styrene is a chain growth reaction and it is induced by any known initiation techniques such as heat, free radical, anionic or cationic addition. The product polystyrene is a white polymer with high clarity and good physical and electrical properties. 

During polymerisation, the vinyl bond of the styrene molecule disappears and 710 kJ/kg heat is released (equivalent to the heat of hydrogenation of the double bond). The density increases from 0.905 g/cm of the pure monomer to 1.045 g/cm of the pure polymer and is a linear function to the conversion. The molecular weight increases from 104 g/mole of the monomer to values between 200000 and 300000 g/mole of the polymer. 

Five different chemical reactions are responsible for converting a monomer to a polymer. These steps are  

Rich Sponge oil (returned to main Overhead naphtha frac.) 

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The contract or other agreements can establish responsibility for the necessary training. This can range from basic safety training at the toller s site to the toll specific process overview and job specific procedure training. 

Development is the phase in which the modules, such as process overview training or safety training modules, are physically con-... 

Process Overview The process overview includes topics related to the equipment configuration, chemical and physical changes achieved in the specific toll, and special safe work practices related to the operations, maintenance and materials. Emphasis should be given to any new equipment and chemical hazards the startup team will encounter. 

Outline work to date (meetings with colleagues, fact-finding, etc.) Recommend establishment of task team (membership, responsibilities) Present process overview ... 

PSM Action Plan —Task team formation Process overview —Benefits... 

FIGURE 2.1 Iron and steel manufacturing process overview. (From U.S. EPA, Development Document for the Proposed Effluent Limitations Guidelines and Standards for the Iron and Steel Manufacturing Point Source Category, EPA-821-B-00-011, U.S. EPA, Washington, DC, 2000.)... 

B. Process overview or summary Provides a brief description of the process with an emphasis on the major hazards in the operation. 

The aim has been to include all those processes that are known by special names, of whatever origin. Of course, only a minority of industrial chemical processes are distinguished by the possession of special names, so this book does not attempt to include all of even the more important processes. Overviews of the industry are provided by other books, notably the encyclopaedias listed below. Many named processes are included in such works, but only a fraction of the names in the present compilation are to be found in them. 

For a process overview, see Chapter 13. The entire process is detailed in Part V. 

Chapter 13, Process Overview, is an overview of the development process, its objectives, and the typical structure of a project. This chapter introduces a set of process patterns that can be customized to different approaches and routes through the method. 

The value chain management processes are presented in a process overview initially and then further detailed with respect to process characteristics and compared within the framework. 

Flowcharts are used for process overview analysis of causes and consequences, lines of defense, and testing data requirements and review of hazard checklist, schedule, and followup on recommendations. 

Fig. 2.9.10. Interdependences of temperature and ions examined in the APCI-FIA-MS(+) process. Overview spectra of AP blend ionised at source temperatures ((a) 400°C and (b) 200°C) resulting in [M + NH4]+ and [M + H]+ ions and [M + NH4P ions of PPG...

Carpena, J., Audubert, F Bernache, D., Boyer, L., Donazzon, B., Lacout, J. L. Senamaud, N. 1998. Apatitic waste forms Process overview. Materials Research Society Symposium Proceedings, 506, 543-549. 

W.C. White, Butadiene production process overview, Chem. Biol. Interact., 166(1-3) 10-14, March 2007. 

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