Sealing technology manual for the process industry

Processing inorganic basic chemicals In the field of inorganic chemistry, nu- merous completely different applica- tions occur. In addition to manufactur- ing, processing, separation, and many other process steps, particularly ex- treme parameters always prevail when handling inorganic basic chemi- cals. In addition to aggressive, to some extent also toxic media, high pres- sures are prevalent. The seals used here must have a broad operating temperature range. Corresponding to the multifaceted applications, high-quality, robust and chemically- resistant materials are required. To meet the high standards of the statu- tory emission values for these pro- cesses, the seal must make a signifi- cant contribution to this. Handling petrochemicals and deriva- tives A typical application in the petrochem- ical industry is so-called steam crack- ing. In addition to being resistant to aggressive chemicals, seals must with- stand high temperatures and pres- sures. In a convection-capable furnace for heating the bottom product, for ex- ample, there are temperatures of up to +600 °C (+1,112 °F) with simultaneous pressure and vaporization. During the subsequent cracking of the resulting gas, the temperatures increase further to +850 °C (+1,562 °F). The real chal- lenge for seals is, however, in the in- tense temperature changes that occur during the subsequent cooling of the gas. The seal must also withstand the pressure increase during the compres- sion of the cracked gas to about 30 bar. The absorption of gases requires the use of chemicals, in particular caustic solution. Polymer production During the handling of polymers (plas- tics), no particularly high demands in terms of pressure and temperature resistance prevail most of the time. Only in some cases, for example, dur- ing the termination of a reaction, tem- peratures as low as –80 °C (–112 °F) may occur, requiring the use of spe- cially developed sealing solutions. In addition, the use of solvents can at- tack conventional sealing materials. Fine and specialty chemicals In the handling of fine and specialty chemicals, seals with an especially high thermal and chemical resistance are required. In addition to the use of harsh and sometimes toxic media, temperatures from +300 °C (+572 °F) down to the low-temperature range are not uncommon in crystallization processes. The material and the seal made from it must be able to cope with this. Production of detergents and per- sonal care products The production of detergents and per- sonal care products, whose require- ments are similar to those of the pharmaceutical industry, makes espe- cially high demands in terms of the purity and hygiene of all process me- dia used. In addition to the lack of dead space of the sealing point, the sealing materials must have the prev- alent approvals and clearances of the pharmaceutical industry and be able to withstand the sophisticated CIP/SIP cleaning media and processes. APPENDIX PRODUCT PORTFOLIO MATERIALS RESISTANCE & PURITY ENGINEERING PLASTICS ELASTOMERIC MATERIALS TECHNICAL FUNDAMENTALS INTRODUCTION 19

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