'Flourides are for Toothpaste'

摘要

The Quantum Morris Ethylene Plant is an NGL light cracker with a five stage cracked gas compresor. During the period from September 1992 through May 1993, the efficiencies of the first, second, and third stages of the cracked gas compressor decreased at an alarming rate with the second stage exhibiting a ten point decline. The first stage decline was mitigated with water injection along with high volume and continuous wash techniques, but similar techniques had no apparent impact on the other two stages. Pressure drop between the first and second stages was also increasign, indicating fouling of the tubes bundles in the interstange coolers. Wash oil was injected at the exchanger inlet in an attermpt to clear the flowpath, but to no avail. Ultimately, high radial vibration at the South end of the compressor's 'B' case (containing the second and third stages) necessitated a plant shutdown on 6/12/93. Excessive fouling of the first stage aftercoolers and the second and third stage compressore internals was found upon disassembly and inspection. This fouling was found to be associated with butane cracking as illustrated by Fig. 1. Tracking of flouride levels during the latter stages of fouling and analysis of foulant samples taken during the shutdown confirmed the presence of flourine within the polymer and a strong correlation to the foulign. Measured flouride level in the butane in May of 1993 varied from 13 to 98 PPM with two out f twelve feeding butane at lower levels of flouride and a single furnace at levels above 30 PPM.