Ordinarily a company building such a plant would either have a research laboratory or production facility that can provide the correct formula and operating conditions, or it would purchase this information. For this case study a compromise between the two mixes of Table 3E-2 was made. The actual numbers are given in Figures 4E-1, 4E-2, and 4E-3.
SCOPE SUMMARY
Product
90,000 lb/yr of general-purpose polystyrene 30,000 lb/yr of medium-impact polystyrene 30,000 lb/yr of high-impact polystyrene
Product Purity
Given in Table 3E-1
Product Package Size
50 lb bags (30% of each product)
200 lb fiber drums (15% of each product)
1,000 lb cardboard cartons, plastic-lined (15% of each product) Bulk shipments by truck or hopper car (40% of each product)
Product Color
100% colorless product
Product Storage
60 days for bags, drums, and cartons 25 days for bulk storage
Raw Materials & Purity
Styrene (see Table 3E-3)
Hydroxy apatite (tricalcium phosphate) (tech grade) Dodecylbenzene sulfonate (tech grade)
Benzoyl peroxide containing 50% water (see safety section) Polybutadiene (polymer grade)
Hydrochloric acid
Raw Material Storage
Styrene - 17 days
Benzoyl peroxide - 15 days Hydrochloric acid - 30 days All other materials - 60 days
Raw Material Obtained in the Following Size Containers
Styrene by barge in 2,200,OOO lb shipments Hydroxyl apatite in 50 lb bags
Dodecylbenzene sulfonate in 5 gal cans Benzoyl peroxide in 300 lb drums Polybutadiene in 50 lb bales
Hydrochloric acid in tank truck shipments
Table 3E-3 Polymerization-Grade Styrene Styrene 99.6% Polymer (none) Aldehydes as CHO 10 ppm Peroxides as 5 ppm Chlorides as Cl 10 ppm Sulfur as S 10 ppm p-tert butylcatechol (TBC) 12 ppm
Source: Bikales, N.M. (ed.): Kirk-Othmer Encyclopedia of Chemical Technology, Wiley, New York, 1970, vol. 13, p. 144.
Byproduct
The 3% of the material which will be offgrade will be sold to toy manufacturers.
Waste Disposal Requirements
A primary and secondary treatment plant to handle all process water. Any solid waste that cannot be sold will be used for landfill. All air laden with polystyrene dust will be sent through bag filters before it is discharged to the atmosphere.
Utilities Requirements
Power will be purchased from a nearby company. (One of the major reasons for locating here was the presence of low-cost, plentiful power.) A gas-fired plant for
125 psig steam will be built. This must be able to supply enough power to operate agitators and cooling-water pumps associated with the reactors when there is a power failure. Gas will be purchased from a local company. Drinking water will be purchased from the community of Martins Ferry, Ohio. Process and cooling water will be obtained from the Ohio River. Both will require treatment before they can be used in the plant.
Future Expansions
A 50% expansion 5 years after startup is expected because of rapid growth in the
Scope Summary 77
Plant Location
Martins Ferry, Ohio, on the Ohio River
Operating Hours Per Year
8,300
Completion Date
October 1974
Shipping Requirements
1. Railroad spur into the plant
2. Road into the plant (plant within a block of a paved road) 3. Barge dock capable of handling one barge
4. Ground level warehouse
Laboratory Requirements
1. for testing tensile strength, stress, strain, and creep characteristics 2. Injection molding machine for testing products
3. Impact testing machine (notched IZOD)
4. Ultracentrifuge for obtaining average molecular weight from viscosity mea- surement in 90% toluene
5. Extruder for testing products
Safety Considerations
The human threshold limit value for styrene vapor in air is 100 ppm. It was set by the American Conference of Governmental Industrial Hygienists. Repeated con- tact with the monomer can produce skin
Styrene liquid and vapor are flammable. At room temperature styrene does not have a large enough vapor pressure to form an explosive mixture. However, above 86” F it can be explosive. Since polymerization can occur and create heat in a storage vessel, a refrigeration system should be used for bulk storage vessels when temperatures regularly exceed 80° F. The reactor area where styrene will be at elevated temperatures should be properly isolated from the rest of the plant to prevent possible fires or explosions. All equipment in that area should be grounded and explosion-proof motors should be used. All open flames should be banned in the styrene reactor and storage
Organic peroxides have a low toxicity. The diacetyl peroxides are sensitive to heat, friction, and shock and may detonate upon the slightest mechanical distur- bance. Benzoyl peroxide dust may explode easily by friction. Anyone designing
this plant should obtain and use the publication Properties and Essential Informa- tion for the Safe Handling and Use of Benzoyl Peroxide.
Benzoyl peroxide as a pure solid is classified as a deflagration hazard. When it is a solid containing about 30% water it is an intermediate fire hazard. As a paste (50% peroxide) it is a low fire or negligible hazard. See reference 18 for a definition of hazard classifications. Benzoyl peroxide containing 50% water will be purchased. It should be stored in a separate cool area, since all peroxides have short half-lives.
References
1. “Containers Cut Shipping Costs for Small Loads,” Chemical Week, Dec. 23, 1970, p. 43.
2 . J a n e ’ s F r e i g h t C o n t a i n e r s , Sampson Low Marston, L o n d o n , p u b l i s h e d p e r i o d i c a l l y .
3. Raymus, G.J.: “Evaluating the Options for Packaging Chemical Products,” Chemical Engineering,
Oct. 8, 1973, p. 67.
4. “Bell Tolls for Little Plants,” Chemical Week, Oct. 28, 1967, p. 127. 5. “Market News Letter,” Chemical Week, May 17, 1969, p. 99. 16. “Chementator,” Chemical Engineering, Aug. 28, 1967, p. 56.
7. “Huge Plants Add to Insurers’ Anxiety,” Chemical and Engineering News, Oct. 23, 1967, p. 30. 8. “Chementator,” Chemical Engineering, Mar. 13, 1967, p. 86.
9. Oil, Paint and Drug Reporter, Apr. 18, 1966, p. 9.
10. Smith, W.M.: Manufacture of Plastics, Reinhold, New York, 1964, pp. 21, 424, 435.
11. Kirk-Othmer Encyclopedia of Chemical Technology, Ed. 2, Wiley, New York, vol. 19, p. 110. 12. Deland, D.L., Purdom, J.R., Schoneman, D.P.: “Elastomers for High Impact Polystyrene,”
Chemical Engineering Progress, July 1967, p. 118.
13. Hay, W.H.: An Introduction to Transport Engineering, Wiley, New York, 1961. 14. Church, J.M.: “Suspension Polymerization, ” Chemical Engineering, Aug. 1, 1966, p. 79.
15. Anderson, E.V., Brown, R., Belton, C.E.: “Styrene - Crude Oil to Polymer,” Industrial and Engineering Chemistry, July 1960, p. 550.
16. Kirk-Othmer Encyclopedia of Chemical Technology, op. cit., p. 72.
17. Chemical Safety Data Sheet SD81, Manufacturing Chemists Association, Washington, D.C., 1960. 18. Noller, D.C., et al., “A Relative Hazard Classification of Organic Peroxides,” I n d u s t r i a l a n d