Q&A

(2016) Question 83: What are the variables you consider which impact slurry oil pump life? What is the typical slurry oil pump life that you experience in normal service?

Slurry oil pump life can be influenced by a number of factors including catalyst carryover from the reactor (which is indicated by BS&W measurements) and the design of the pump itself.

(2016) Question 84: What effects, if any, have you observed concerning slurry pump-around exchanger fouling when processing shale oil/tight oil feeds?

Our expectation would be that there could be issues on both the slurry side (tube side) of the exchangers and the shell side in FCC feed preheat service. Of the two, we would expect fouling on the feed side of a slurry/feed exchanger to be most impacted due to the waxy nature of shale oils with the propensity of paraffins to undergo thermal cracking to form coke in high temperature services.

(2015) Question 67: The industry continues to experience process safety incidents associated with FCC electrostatic precipitators. What are you doing to prevent these incidents?

Phillips 66 has six ESPs (electrostatic precipitators) in service. We have not been immune to serious incidents on our ESPs. In 1994, we had an ESP explosion, which led to a fatality. So, in order to minimize the likelihood of these kinds of incidents happening again, the company has a standard that all of the refineries are required to follow.

(2015) Question 68: How does your organization share operational and process safety information to foster an environment of continuous improvement?

MPC utilizes the AFPM Safety Portal to communicate and share experiences and knowledge within our FCC Advisory Group. It is a vital component of our goal to improve process safety performance. We also have a Process Safety Advisory Program to learn from external industry and internal MPC process safety events, significant near misses, and high value learning events.

(2015) Question 69: What criteria do you follow to decide installation of remote-operated isolation valves to arrest loss of containment from vessels, column bottoms, etc.? Do you recommend any safeguards to avoid spurious activation of these remote-operated valves?

Remotely operated isolation valves are used to isolate systems during loss of primary containment to prevent further leakage that can lead to pool fires or vapor cloud explosions. They are manual valves, which are activated by pushing a button on the local panel that is located at a safe distance from the valve.

(2015) Question 70: With environmental regulations becoming more stringent on FCC stack emissions, what are your available options to achieve the required level of SOx (sulfur oxide) and NOx (nitrogen oxide) emissions?

From both the SOx and NOx perspective, there is a cat feed hydrotreater that will reduce both your sulfur and nitrogen compounds in the feed to your cat cracker, which will produce lower SOx and NOx emissions. It will reduce your metals in the feed and increase the hydrogen content of the feed, which will improve FCC unit conversion.

(2015) Question 71: Describe your practices for minimizing flaring and flue gas emissions during startup, shutdown, and malfunction operations?

Our Marathon FCCs all have a flareless startup procedure, but the type of equipment we have at our different FCCs varies somewhat. I pulled together an overview of what we have at our different plants and some licensor recommendations I learned through discussions I have had with them. I think we all agree that it makes sense, from a financial standpoint, to recover that material enough, whether or not the environmental stance is compelling us. It is just a part of being a good neighbor to the community in which we operate.

(2015) Question 72: The FCC is LPG-constrained, and the refinery is octane short. What are your suggested options to increase FCC gasoline octane while minimizing any associated increase in LPG yield?

When the FCC is constrained in LPG and short on octane, the feed is one of the most important parameters for yields and quality of the yields. So, if you can, blend in more aromatic feeds. Or if you have feed pretreat, backing off from it will help improve your gasoline octane.

(2015) Question 73: Octane may become an issue as refiners increase severity on the FCC gasoline post-treatment units. What are your options available to address octane debits?

When you want to reduce the sulfur in gasoline, one of the first options you can do is undercut the gasoline. The sulfur distribution in gasoline is typically exponential. If you reduce the cutpoint of your gasoline, you will reduce the amount of sulfur in your gasoline. Sulfur exhibits an exponential distribution.

(2015) Question 74: For a unit targeting low vapor pressure gasoline, which variables have the greatest impact on isopentane production?

While the question asks specifically about isopentane production, other C5 hydrocarbons also have significant vapor pressure. Isopentane has a Reid Vapor Pressure (RVP) of 20 psi (pounds per square inch); n-pentane has an RVP of 16 psi; and, the C5 olefins have RVPs between 14 and 26 psi9. For refineries desiring to minimize RVP, it is also important to minimize the quantity of C4s in the gasoline pool since C4s have even higher vapor pressures than C5s.

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