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Relief device sizing for ethylene decompositions—high pressure polyethylene industry
Author(s) -
Shan David I
Publication year - 2008
Publication title -
process safety progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.378
H-Index - 40
eISSN - 1547-5913
pISSN - 1066-8527
DOI - 10.1002/prs.10214
Subject(s) - polyethylene , ethylene , sizing , materials science , separator (oil production) , decomposition , thermal decomposition , autoclave , high pressure , polymer chemistry , chemical engineering , forensic engineering , thermodynamics , chemistry , composite material , engineering , organic chemistry , metallurgy , catalysis , physics
This paper discusses revisions to a method previously used for sizing relief devices (rupture disks) for vessels in high pressure polyethylene processes. The Re‐evaluation was forced by an unexpectedly high peak pressure in a product separator (high pressure separator, HPS) when an ethylene decomposition occurred. A method, based on revised equations for calculating the rate of pressure rise, is presented for determining relief requirements for ethylene decomposition in a confined space. The method applies to both HPSs and polyethylene autoclave reactors. Causes of decompositions and effect of comonomers are also discussed. Simulations for other events at different operating conditions, not shown, indicate a good match for peak pressures. Therefore, the described equations provide a good estimate of ethylene decomposition peak pressures given the initial conditions. Although these methods were derived specifically for ethylene decompositions, the methods could be used for other decompositions. © 2007 American Institute of Chemical Engineers Process Saf Prog 2007