Q & A > Question Details
Currently Chloride content in our straight run Heavy Naphtha (HN) feed is 800 PPM. So, please tell me the maximum limit of Chloride content in HN is acceptable for NHT unit to minimize the chloride corrosion and salt formation in the system (for Naphtha Hydrotreating Unit).
 
Answers
27/03/2017 A: Virendra Kapoor, Petroleum Refining Consultants, vkkapoor9@yahoo.com
I appreciate the comments of Mr. Ganesh Maturu. It may be 800 ppb.
22/03/2017 A: Virendra Kapoor, Petroleum Refining Consultants, vkkapoor9@yahoo.com
800 ppm is very high. It should be minimised by managing slops & other methods. Selection of crude is important. Chlorinated solvents are used in crude production that lead to more chloride in Naphtha cut. So high chloride is source of corrosion. Selection of metallurgy is very important. Washing water is necessary. Try to follow recommendation of process licensor & catalyst vendor.
21/03/2017 A: Ganesh Maturu, Self, maturu.ganesh@gmail.com
It seems u mentioned 800ppb. No crude in the world contains 800ppm chloride in it HN stream. If it is 800ppb, calculate nh4cl sublimation temperature and if it is higher than temperature at wash water injection point, you still have margin. You may have ro change intermittent to continuous wash water injection if chloride limit exceeds 1-2 ppm.
20/03/2017 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Most people try to maintain <1ppm of Chloride in their naphtha. The actual amount your system can tolerate without forming salts also depends on the hydrogen flow rate, the amount of nitrogen present, the amount of Chloride in the make up hydrogen, and water wash practices (if a water wash is used or not and where that water wash is located). 800 ppm sounds extremely high and is very likely to lead to ammonium chloride salt fouling and/or corrosion. Performance of salt point calculations is an easy way to estimate how tolerant your system will be of chlorides in the feed.
20/03/2017 A: Eric Hennings, Technip Stone & Webster, EHennings@technip.com
800 ppm is a very high organic chloride content in naphtha. Try to eliminate sources. Sources can be machine shop solvents in slop, paraffin dispersants in crude or other chemicals. Often, organic chlorides will also show up as low pH in CDU overhead.