Q & A > Alkylation
Date  Replies
19/07/2013 Q: Can someone please help me with information on any recent advances in the alkylation process in a petroleum refinery and differences in the action of solid acid catalyst and liquid acid catalyst. (3)
22/05/2013 Q: Can propylene be used as a co-feed to H2SO4 Alkylation plant? The plant is designed for C4= with iso-C4 case only. What are the pros and cons of co-feeding? (1)
17/06/2012 Q: Excuse my ignorance; I am neither a chemist, nor an engineer. My question revolves around RVP and RON properties of aklylate and refomrate.
From what I have read (obviously not enough), my logic dictates:
1) Unsaturated hydrocarbon molecules are more volatile than that saturated ones, thus will have higher RVP
2) Lighter hydrocarbon molecules are more volatile than longer chains, thus will have a higher RVP.
Questions that are driving me nuts:
1) How can a naphtha feed (with more saturated content) going into a catalytic reformation can have a higher RVP, than the resulting reformate which has more aromatics (unsaturated, cyclical = more volitile) content?
2) Why does alkylate which has more saturated molecules than reformate have lower RON and higher RVP?
3) Which is the most important contributor to RVP of a gasoline blendstock - the length of the hydrocarbon chain or it being un/saturation with hydrogen atoms? In other words, which has higher RVP - an unsaturated aromatic benzene molecule or a saturated paraffin pentane?
(4)
13/05/2012 Q: Basic differences between AFQRJOS Issue 25 v Issue 26 may please be explained. (1)
01/05/2012 Q: Over past 5 months, we have suffered from increased (by 25%, 30 ton/day) sulfuric acid consumption of our alkylation unit.
Now, we doubt increased non-regenerated alkyl sulfate formed by butadiene and / or increased acid soluble oil formed by olefin polymerization.
1. Actually, the butadiene content of C4 olefin feed has widely been ranged from 0.2 to 1.0% according to our lab analysis (thru PONA analysis), and apparently there is no tend that the butadiene content has been increased. Are there any methods to analyze the butadiene content more precisely. It's known that the butadiene makes non-regenerated alkyl sulfate by strong reaction with sulfuric acid and goes to acid phase, which reduces acid concentration. Are there any methods to analyze the alkyl sulfate content in the spent acid?
2. The C4 olefin feed comes from our RFCC unit which uses ZSM-5 as an additive to boost propylene production as other RFCC's. Can ZSM-5 increase the butadiene content in the C4 olefin feed? Actually, we have used ZSM-5 for a long time in the RFCC unit, and recently we changed the brand of ZSM-5 at the end of last year. Can the butadiene content in the C4 olefin feed be much affected by the type and vendor of ZSM-5?
3. Are there any methods to analyze the acid soluble oil content in the spent acid? Can higher iC4/Olefin ratio reduce the acid soluble oil content in the spent acid?
(4)
02/03/2012 Q: How to keep the pH in neutralization pit neutra? Alkylation unit uses HF and in the neutralization pit we use KOH. The pH is very erratic ranging from 8-14. (2)
30/10/2011 Q: With regard to application of catalysts in Isomerisation process, I would like to know about the overall comparison between tradition catalyst i.e. Aluminium Chloride and novel catalysts based on platinium element. In point of view of economical criteria which case has been suggested? (3)
01/11/2010 Q: I am interested in knowing more about the options of value addition to C4 stream produced in FCC / CDU.
C4 produced consists of a mixture of N-Butane, Iso-Butane and Butylenes.
Following value addition routes exist:
a) Recover Butylenes and convert them to Propylene using OCT (Olefins conversion technology).
b) Recover Butylenes, Isobutane and convert them to Alkylate in Alkylation.
c) Recover Iso-butane and use as a feed to Alkylation.
I would like to know if there are other routes of value addition available or any synergy with a Petrochemical complex. What are the options for N-Butane for value addition?
(4)
09/07/2010 Q: What is odorless kerosene? And how is it processed? (2)
21/05/2010 Q: I am working on CDU as a field operator.
I want to know why NH3 or NH3H2O is injected in overhead line of distillation column?
Why dont we use NAOH for nutralization there? Even NAOH is cheaper then Ammonical water.
(5)
11/09/2009 Q: What are the typical benefit one could expect from APC implementation in Alky (sulphuric acid based) unit? Also, has anyone used early event system to forewarn operator on reaction section operation? (1)
12/05/2009 Q: I read that most of the existing alkylation units use HF in their process and the newer ones sulfuric acid. How is the flow of HF measured - and the H2SO4?  
01/05/2008 Q: What are the conditions leading to brine production in a Catalyst cooler?  
03/12/2007 Q: Would you please share experiences of C4/C5 alkylation?
We are adding C5 alkylation to existing C4 alkylation.
It has a SAR (Sulfuric Acid Regeneration) unit.
Do they usually feed C4 and C5 mixture?
1. Is there any existing unit which is fed C4 and C5 separately?
C5 segregation cause any problem? Licensor says we consume less Sulfuric Acid than mixed feed.
2. With segregated C5 feed, spent acid strength will be 87wt%. Are there any critical reliability issues due to lower spent acid strength?
- reactor corrosion
- spent acid disposal and regeneration unit (SAR)
(1)
29/11/2007 Q: What is the present global alkylation capacity? And the largest alkylation unit? (5)
16/09/2007 Q: If my gasoline pool is not limited by Rvp, then is it advisable to go for a isomerization unit if I have iso pentane availability. Iso pentane RON is 83.5 and isomerate is 87.5 (2)
11/09/2007 Q: Can anybody share experiences of using high efficiency trays in an isostripper column? (1)
05/09/2007 Q: What is the status of the first commercialization projects using solid alkylation catalysts? (3)
17/08/2007 Q: In our naphtha hydrotreating unit, iron contents in stripper overhead boot are being reported on higher side for the last month. So far we have tried the following:
1. Increased corrosion inhibitor injection from 3 wt ppm (design) to 7 wt ppm.
2. Replaced the corrosion inhibitor
3. Cold condensate injection in reactor effluent increased from 3 to 5.5% of feed.
But iron contents are still high (2~3 ppm).
What could be the possible cause and what is the solution?
(4)
22/07/2007 Q: Are there any recent alkylation projects that you can comment on where mass transfer efficiency improvements showed significant reductions in required acid consumption? Also, what recent improvements have resulted in reduced water wash or caustic wash requirements? (5)