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本设计由许春华老师指导，他提出了许多宝贵的意见来帮助我完成了可发性聚苯乙烯聚合工段工艺的设计，在此我衷心感谢他。
由于可发性聚苯乙烯聚合工段工艺设计的知识交叉面很广，而我的知识和经验有限，设计错误和不妥之处，恳请批阅老师批评指正。
Illustration
Styrene-based resin according to the structure can be divided into more than 20 categories, there are general purpose polystyrene (GPPS), expanded polystyrene (EPS), high impact polystyrene (HIPS) and so on. Expandable Polystyrene (Expandable Polystyrene, referred to as EPS) commonly known as the Department of polystyrene and styrene copolymer is a kind of mixture with resin the physical blowing agent and other additives mixture. It has a lightweight, inexpensive price, low thermal conductivity, low water absorption, good electrical insulation properties, excellent long-lasting thermal insulation, a unique cushioning and shock resistance, aging resistance and water resistance, thus it has been widely applied in many fields.
According to assigned design task book, the design is about of Expandable Polystyrene polymerization process section that the annual production capacity is 200,000 tons. Through access to a lot of literature and research internships, can be made of polystyrene for general performance and process performance are summarized, the production technology of Expandable Polystyrene and production equipment are scientific proofed and designed.
Currently industrialized production methods are mainly suspension polymerization and bulk polymerization. Expandable polystyrene is a typical product of aqueous suspension process, a suspension polymerization with high purity, low cost, easy to remove the heat of polymerization, the viscosity increases with the amount of change elements is small, easy to control the temperature, and particle size can be controlled in a smaller amplitude range and so on. Polystyrene in industrial pipeline can be made of by one-step impregnation (one-step), two-step impregnation method (two-step). With a simple process, and the advantages of low investment costs, the most companies now generally dominated by one step process.
The factors that impact polystyrene products can be water quality, dispersing agent, initiator, blowing agent, the reaction temperature, the reaction vessel and stirred forms. For the technical requirements of the production of Expandable Polystyrene, the design in accordance with international standards, select the appropriate formulation and production process conditions. The reaction mechanism in my design is free radical polymerization，suspension polymerization process used in styrene monomer, water as suspension medium, low temperature suspension polymerization step production process. Pentane as blowing agents, calcium phosphate dispersant, organic peroxides (dibenzoyl peroxide, t-butyl peroxybenzoate), respectively as low and high temperature initiators, alkanes with hexabromocyclododecane, dicumyl peroxide as a flame retardant, and other additives. With stirring, a styrene monomer in the form of droplets suspended in water and polymerized by free radical reaction mechanism reaction, then add the foaming agent (pentane). When blowing at a certain temperature and pressure, the foaming agent penetrate into the beads.After washing, centrifugation and drying, screening, coating, packaging, prepared products can be made of polystyrene beads.
Originally, the design is about of Expandable Polystyrene polymerization process section that the annual production capacity is 200,000 tons. Combining the producing craft and the products, the balance of materials and energy has been calculated. According to calculations, there are three classes in the daily in the frequency of continuous production. The products divide into 466 batches to produce. So each batch of the production yield is 431450 kg. The set of basic equipment can be. According to an annual output of 200,000 tons of the Expandable Polystyrene polymerization process section, a workshop is designed. The workshop adopts rectangular and double layer. The size of workshop is (length × width × height) 30m×24m×16m. During the design of workshop, the rectangular workshop is advantaged to design the whole workshop, and advantage to arrange equipments and save areas, and also easy to adopt the light and ventilate well. Plant sitting，according to the natural geographical features, transportation, water and power supply conditions, construction conditions and worker housing conditions were optimized selected.