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(2015) Question 48: What is your experience bringing hydrocracking catalyst online without ammonia attenuation? Are there alternative methods or technologies to temper catalyst activity without adding ammonia?

Hydrocracking catalyst needs to be passivated during sulfiding to avoid potential temperature runaway as temperatures are increased to complete the sulfiding process. In our experience, there are four different ways that we attenuate the catalyst activity. The first is to inject ammonia prior to the high temperature sulfiding to passivate the catalyst.
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(2015) Question 49: Each hydroprocessing unit has an optimum strategy for full load-catalyst replacement: oxidized versus presulfided. How does the strategy change for a partial reload (e.g., top-bed skim or replacement)? Are there other situations when pre-activation is justified?

Use of either oxidized or presulfided catalysts can work fine. It depends on safety approach, cost allowance, time goals, and handling the processing preference. The main point is safely carrying out this skimming operation, whether or not it is oxidized catalyst or presulfided catalyst.
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(2015) Question 51: What is your best method for monitoring salt level in a diesel salt dryer? What are your current guidelines for salt usage and capacity? What are your best practices for loading and monitoring salt dryer performance?

We prefer not to use salt dryers in new ULSD designs. In recent ULSD designs, we will put in a vacuum dryer, or we will re-boil the stripper to meet the low water specs. If there are less stringent water specs, using a coalescer can be sufficient. One of our most recent new units will have a coalescer followed by a vacuum dryer.
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(2015) Question 52: What approaches are effective for you to reduce aromatic levels in the ULSD product streams?

To reduce aromatic levels, we definitely need to assess the unit’s capabilities. Is it a high hydrogen partial pressure unit with psig greater than 800, and does it have a higher than 4.0 hydrogen availability ratio (HAR)? If both answers are greater than those reference points, then full loading of NiMo catalyst can be employed to give higher hydrogenation and very good aromatic saturation results.
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(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.
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(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.
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(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.
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(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.
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(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. 
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