ITW Services - Ethylene furnace run length increase (Naphtha Cracker)

Ethylene Furnace Run Length Increase (Naphtha Cracker)

The Ethylene Unit runs at very high temperature conditions, say among 820-860 °C (1530-1605 °F), depending on the feed type. In general, the liquid feed Crackers have a higher transfer line temperature than the gas ones. Under such very severe conditions the feed is cracked in the presence of steam. Although the cracking is performed under high velocity conditions, coke builds up into the furnace coils and limits furnace run length.

Coke formation is particularly severe with liquid feedstocks (e.g. naphtha) and leads to furnace stoppage and decoking of the same. A typical run length of a naphtha furnace is around 40 days or even less. ITW has developed and patented a novel chemistry which is capable of preventing coke formation even at very high temperature conditions.

The patented chemistry is added directly into the liquid feed by means of a dosing pump. Achieved increased furnace run length range from 50% to 70% (i.e. from 40 days to 60-68 days). Additional benefits of the technology are, among the others:

  • More stable furnace operation and reduced delta P
  • Reduced dilution steam/feed ratio
  • Reduced TLX fouling

Not any single detrimental effect has been noticed during any application in the field.