In our Vacuum Unit we have 2 Identical Trains, Train -1 constructed in 1984 and 2 constructed in 1989. Our Vacuum system is Wet Vacuum with 2 Pre- Condensers in parallel and 3 Stage Ejector system, each having 3 no. of Vacuum Ejectors, with Condenser, with the cooling medium being Sea Water and the Sea Water entry is to the Pre-Condensers and it's return going to the other 3 Stage condensers simultaneously and also provided with a By-Pass to increase the flow to those condensers if and when required. Actually in the middle of May 2023, we experienced sudden break in vacuum in only Train - 1 and this phenomenon was continuing on & off, with this phenomenon occurring every 7-10 days and would resolve by switching the Ejectors and /or hammering the Pre-Condensers leg lines, till our Scheduled Biennial Turnaround in October 2023. And after Start-up of the unit on October 31, 2023, till December 30/31 2023 for about a couple of months the unit was running very smoothly, before the vacuum issue started cropping up again and this time the frequency of the drop/break in Vacuum was about 10-15 days, continuing upto March 2024. But, our Operation personnel thought this is due to the Pre-condensers leg line getting blocked due to Metal rust & corrosion and instructed to externally Hammer those leg lines twice in every shift from February upto Middle of March 2024., and by that that issue also resolved. And for a period of more than 6 months upto 2024 October first week, we did not face any issue except little increase in Vacuum twice or thrice when sea water flow was getting dropped, or more lighter in feed from Tankfarm. Also, as compared to the other Train, we were having 2 ejectors more online i.e.., 6 Ejectors with 2 each in all the 3 stages. But again we faced sudden break in Vacuum itself on October 5th at around 04:00 hrs, even with unit running on extremely low Throughput. So, I kindly request you to help with this issue. Note:- As per my observation, I have noticed 2 separate phenomenon happening with none being related to each other or happening together even once. 1. Pre-Condensers leg line temperatures getting low 2. 3rd Stage Condenser outlet temperature getting high which in turn increases the pressure of the non-condensible from the Hotwell increasing the back-pressure of the system irrespective of burning in our Heater or flaring it.

Currently, the refinery is processing crude oil with a high H2S content. How can this affect the distillation unit? Would it affect the cap and transfer lines? What do you recommend I apply?

We have a new hydrogen production unit designed by Haldor topsoe. The outside temperature of reformer skin exceeds 350c in some point especially in locations close to burners. The contractor cool it down by directing low pressure steam to the outside surface by flexible hoses. Here I have two questions:

1: Is it normal to have such a high temperature at the outside while it is designed based on Euro 5.

2: Is it accepted to cool it down using LPS? Will that damage the iron structure or not?

What’s the difference between the filming amine and corrosion inhibitors? Can we use corrosion inhibitors as a filming amine?

If anyone could help me in calculating Vapour Pressure of heavy hydrocarbon products such as fuel oil, base oil, vacuum residue etc... by any means of other physical properties like flash point, density, viscosity, etc..., I would be highly appreciated. That's for pump performance calculations!

What is needed to significantly increase production of bio-LPG, renewable marine diesel, and bio-aromatic hydrocarbons like BTX?

Integrated refinery and cracker plant, processing Naphtha, Ethane, Propane, LPG as feed, experiencing high Vinyl Acetylene in their Mixed C4 feed. Severity controlled, however, VA concentration is very high. We are interested in understanding the likely reasons for high Vinyl Acetylene formation? What are the parameter need to be checked to control Vinyl Acetylene concentration? What parameters should be monitored to maximize the throughput of the butadiene unit while limiting Vinyl Acetylene contamination?

Q1. I would like to understand the importance of Diesel feed introduction at 180degC as feed in VGO hydrotreating units before VGO gets replaced with diesel at 260-280degC?

Q2. What is the issue if VGO feed is introduced directly to the VGO hydrotreating reactor at 180degC?

Q3. Where does congealing in VGO units occur and why? It is often seen cold Straight VGO coming from storage tanks maintained at 80 degC flowing freely?

Q1. In Hydrotreating units(Diesel and VGO), why is that Feed introduction is not allowed above 200degC?

Q2. During Normal startup post maintanence work, having H2S in HP loop above 1000ppm, why feed introduction is done at 180degC only, what would be the issue if feed introduction is done at 230 or 240degC and why it is not generally not recommended?

I am facing a problem in vibration of control valve controlling atmospheric residue at 10 bar pressure,175 'C temperature and 620-630 m3/hr flow. Instrument team dropped the valve and found internals parts damaged and they explained that the reason of damaging the valve internals due to low opening of 15-16%.

The attended and fixed the valve but same vibrations still coming.

Can anyone explain the exact reason and solution for this?

How can hydroprocessing operators better manage the high heat release during O2 and olefin hydrogenation (for example, when processing lipid feeds)?

Why are some of the world’s best refineries more efficient than some of the world’s newest refineries?

What is needed for large-scale upcycling of plastic waste to valuable chemicals like polyethylene?

How are cross-functional teams achieving operational efficiency and process safety targets?

What areas of expertise are needed to mitigate constraints in plant/facility staffing levels?

How can fractionation upgrades be achieved without expensive metallurgical upgrades?

How can refiners overcome challenges during FCC fast pyrolysis bio-oils (FPBO) co-processing with vacuum gasoil (VGO)?

How to reduce sox emissions from FCC regenerator by changing which operating conditions..? Like Catalyst circulation reduction, combustor temperature reduction, ROT reduction etc.

Is it feasible to process slack wax in a delayed coker? If so, what are the potential benefits and operational challenges?

Regarding visual inspection of Vacuum Distillation Bottom Product of Used Oil Re-refining, the sample appears to be more viscous after heating, and less viscous on cooling! Is there an explanation for that?

What potential limitations might arise when attempting to reduce the coke drum pressure to the design values in Delayed Coker Units? Additionally, what types of investments might be necessary if we aim to further decrease the pressure?

How do you manage the pressure in the Fractionator within a Delayed Coker Unit? From what I understand, both the Fractionator and Coke Drum pressures are regulated by the inlet pressure of the Wet Gas Compressor. However, during drum switch operations, significant fluctuations in the Fractionator top pressure make it challenging to maintain stable control. Are there any control strategies or philosophies that could be applied to effectively manage the pressure in the Fractionator and Coke Drum in the Delayed Coker Unit in addition to inlet pressure control of WGC?

 How to prevent fouling in feed/effuent exchanger of sour water stripper unit?

How to decide the turndown of plant during design phase?

How to prevent fouling in feed / effluent exchanger of hydrotreatement unit in refinery?