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What are the major modifications are required for processing Light kero in DHDS unit in place of Diesel ?
 
Answers
05/04/2015 A: Sarath Konda, DuPont India, sharathsatya@gmail.com
Kerosene feed will result in Higher Vaporization which could increase reactor pressure drop. Unit pressure can be optimized for adequate aromatic saturation to meet sulfur and smoke point of the product. DHDS catalyst should work fine for Kero service and also unit should not require any modifications
30/12/2014 A: Ganesh Maturu, Self, maturu.ganesh@gmail.com
Following changes in both reactor and separation sections
1. First of all you will select the catalyst which suits to kerosene applications. Contacting any catalyst vendor will give more details about the available latest catalysts
2. Required reactor pressure in DHDS is high compared to kero hydrotreater. You need to reduce the reactor pressure to optimum level by contacting catalyst vendor. Reduction in pressure is mainly for utility savings.
3. Required gas/oil ratio also decreases in kero hydrotreater. Maintaining optimum value improves catalyst stability with less utility costs. Make sure that recycle gas compressor is not in surge limit for lower recycle gas flows.
4. Also kerosene is lighter component, more vapors may be observed in reactor effluent-feed exchangers and hence requires detailed adequacy of the exchangers mainly vibration issues due to velocity.
5. Separators and stripper may be adequate as no major changes in vapor-liquid loads.
29/12/2014 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
You will want to make sure that you don't hit a dry point in the reactor. That can lead to coking and/or color issues on the kerosene. You would also want to check the inlet distributor design on your reactor to make sure it is ok for the new feed conditions.
Kero is easier to hydrotreat than diesel. The biggest change that happens with the feed switch is that the kero is more volatile, so you will get more vaporization of the feed. Naphtha hydrotreaters are normally vapor phase, and diesel hydrotreaters are mostly liquid phase, but with kero being between the two it can go either way depending on your conditions.
29/12/2014 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
There may be no major modifications required. Calculate a heat and material balance for the new operation and compare the figures with the equipment data sheets. Check key line pressure drops using the new flowing properties.