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What is effect of Pressure, temperature, LHSV and H2/Feed ratio on gas oil sulfur removal?
 
Answers
25/10/2016 A: Sridhar Balakrishnan, Bharat Oman Refineries Limited , laksrid@yahoo.com
Effect of temperature and pressure on gas oil sulphur removal are increase in temperature increases hydrogenation , but can decrease the active sites of catalyst. Increase in pressure increase in hydrogen partial pressure and increase the severity of hydrogenation reactions.


25/10/2016 A: utkarsh mishra, Ingenero Technologies, utkarsh1612mishra@gmail.com
Generally speaking following is the dependence between variables, if one of the variable is changed keeping all other variables constant:
1) Pressure: as you increase reactor pressure (keeping constant H2 purity in recycle gas), catalyst coking rate decreases & you require lesser inlet temperature for same amount of S removal.
2) Temperature: as you increase reactor inlet temperature, more amount of S removal takes place but catalyst coking rate also increases.
3) LHSV : as you increase LHSV, you need higher inlet temperature & more H2 flow to maintain same spec of S in reactor product. catalyst coking also increases marginally.
4) H2/feed ratio: Typically higher H2/feed ratio means you may have lesser catalyst coking rate & you require lesser inlet temperature for same amount of S removal.
25/10/2016 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
The first four are called interrelated variables. If you change the value of one of them, you can change one or more of the others and achieve the same sulfur and nitrogen removal. For a unit being designed, the selection of the value of each can be optimized. One of the exercises in one of my workshops is to do exactly that.
24/10/2016 A: Saleh Daryabari, Senior Process Engineer of RCD and RFCC, Arak Refinery, daryabari@gmail.com
Higher Hydrogen partial pressure, higher temperature, lower LHSV and higher Hydrogen to Hydrocarbon ratio in hydrotreating reactors, improve sulfur removal reactions.