Filters

(2012) Question 52: What is your recommended method for mitigating fouling in reforming unit recycle compressors? Has any technique proven successful? Is anyone using reformate to clean the compressor online?

The best method for reducing fouling in the compressor is to take the nitrogen out of the feed. In Valero, we have recently reviewed our naphtha hydrotreater performance. In a lot of cases, we found that the naphtha hydrotreaters can actually be pressure drop-limited versus activity-limited.
Read more

(2012) Question 53: What is the panel’s experience with addressing reforming unit stabilizer salting?

I actually have three examples that all apply to a reformer stabilizer. The first slide shows what we call our hot wash. By that, I mean we do not lower the temperatures. We will keep the bottoms re-boil temp in the 440°F to 480°F range. We then have two options on this hot wash. If we just see a high differential pressure on the overhead cooler, then we will put the water in front of that air cooler.
Read more

(2012) Question 54: Does the panel have experience chemically cleaning their reforming unit reactor circuit to minimize the lower explosive limit (LEL) when opening up equipment to the atmosphere in an effort to comply with environmental regulation? If so, is the chemical compatible with the catalyst?

HollyFrontier does not have experience using a chemical in this case. Our normal procedure involves coke burning prior to opening the reactor, and there has not been a problem with LEL in the system after that.
Read more

(2014) Question 82: Units operating with low main fractionator bottoms yield encounter a number of problems including coking and fouling in the slurry system and increased catalyst loading in the circulating slurry. What problems have you encountered and what practices have you done to manage these problems?

Units operating with low main fractionator bottoms yield encounter a number of problems including coking and fouling in the slurry system and increased catalyst loading in the circulating slurry. What problems have you encountered and what practices have you done to manage these problems?
Read more

(2014) Question 83: As the time between FCC unit turnaround events are continuously being extended, what areas have you identified as having a high likelihood of failure due to erosion and what preventive measures can be taken to avoid such failures?

Erosion due to catalyst impact is often a strong function of particle velocity. However overall operating conditions, such as superficial velocity, are often insufficient to predict local erosion characteristics in FCC equipment where the likelihood and severity of erosion is influenced by local catalyst acceleration and impact. The mass, velocity, angle of impact, surface material and other factors all influence this local erosion behavior.
Read more