| American Fuel & Petrochemical Manufacturers

Question 72: Recent drone technology advancements have enabled refiners and contractors to improve the efficiency of maintenance and inspection activities. With this, how are your hot work permits and general safety policies evolving to sustain adequate asset and personnel protection at all times? For instance, what additional safety permits or considerations would apply for drone use and aerial inspections?

In June 2016, the Federal Aviation Administration (FAA)announced that it had finalized the first operational rules for routine commercial use of small, unmanned aircraft systems (UASs) including “drones”. According to industry estimates, the rule could generate more than $82 billion for the U.S. economy and create more than 100,000 new jobs over the next 10 years.

Question 71: In your experience, what factors affect NOx emissions for a partial-burn FCC with a CO boiler? How do you achieve 50 ppm CO emissions while simultaneously minimizing NOx emissions through the stack?

Combustor-or incinerator-style CO boilers can produce lower NOx emissions than direct burning CO boilers (COBs). COBs with cold planes where the CO is combusted (package boilers, as an example) require high firing rates to combust the CO to acceptable levels, thereby increasing the liberation and NOx contribution.

Question 70: What is your method for measuring naphthenic acid [TAN (total acid number)] in FCC feed? Is this method affected by VABP (volume average boiling point) or Concarbon (Conradson carbon) content? Do you have data that validates an appropriate integrity operating window (IOW) trigger level? If above the trigger level, what is your recommended corrective action (extra inspection, change crude/slate, etc.)?

In terms of TAN number, we typically recommend the standard test method UOP 565, which can be found through the ASTM (American Society for Testing and Materials) website.

Question 69: Our FCC unit is limited by coke burn and high regenerator temperatures. What catalyst and operational changes have you implemented to maximize the conversion of heavy feeds and increase the amount of resid we can process without running into our regenerator limits and increasing dry gas production?

Considering the stated goals and constraints, particularly being limited by regenerator temperature and coke-burning capacity, it will be necessary to reduce delta coke without significantly increasing the reactor heat demand.

Question 68: What is your experience with processing raw crude in the FCC? What types of crude have you tried to process in the FCC? What are the yield impacts? Any corrosion issues associated with this mode of operation? What additional corrosion monitoring is needed?

I have not had any experience running raw crude directly into an FCC unit; however, I know there are refiners out there that do. Many refiners who are running a high percentage of tight oils into their crude units have found that there is typically a shortage of FCC feed, which has led to some of them charging tight oils straight into the FCC.

Question 67: As distillate demand has decreased, current economics favor maximizing gasoline and octane. What operating and catalyst changes do you recommend for increasing octane barrels?

An FCC unit contributes to the gasoline pool through both cracked gasoline production and C4s production, which is used to generate high octane alkylate for blending.

Question 66: In your experience, how does changing the feed cutpoints impact FCC conversion and product yields? How does the LP (liquefied petroleum) determine where to make these cutpoints?

Deeper cuts will not have as high a conversion as will lighter cuts. For example, an FCC charge API gravity of 22 may have a conversion of 83%, while a lighter gravity of 23 will show conversion one point higher at 84%.

Question 65: Please comment on which FCC feed types you are currently processing and what chemicals you are using for gas plant corrosion prevention. Is waterwashing sufficient to sustain adequate unit reliability?

Our refinery typically runs Western Canadian Crudes, SYN, and some conventional heavy crudes.

Question 64: What are your typical operating guidelines to prevent compressor surge episodes? How closely do your FCCU operators approach the actual surge line of a compressor before adjusting operation?

[United Refining Company (URC)] The unit engineer/compressor manufacturer should be able to provide guidelines to prevent surge episodes. These guidelines may include safe windows of operation for air rates, discharge pressures, and discharge temperatures.

Question 63: What are your current methods used for regenerator cyclone temperature control? Do you use water sprays or steam injection?

In the early days of FCC, the normal bed and dilute-phase operating temperatures –being less than 1100°F –did not support CO combustion. These units operated with high levels of carbon on catalyst and about 10 vol% CO in the flue gas with almost no excess oxygen in the flue gas.