Q&A

(2013) Question 27: What options are refiners considering addressing upcoming Tier 3 Fuel Standards [10 wppm (weight parts per billion) annual average sulfur in gasoline]?

Tier 3 fuel is lowering sulfur yet again in gasoline. The crude oil sulfurs have been coming down also with the tight oil, so some people have asked the question: Is processing more tight oil actually going to get us on-spec on Tier 3? The answer is no, not really. It is not going to have that significant of an impact on your gasoline sulfurs, obviously, without other processing.

(2013) Question 28: Is the changing quantity of pentanes and pentenes in refinery streams and tightening gasoline regulations leading to operators considering different processing strategies in order to maintain gasoline blend pool specifications? Comment on increased pentene alkylation, decreased pentane isomerization, or other disposition sources.

The pentenes, also called amylenes, can be fed to the alkylation unit and be alkylated. However, you make a lot of ASO (acid-soluble oil) and the yield is not that great; so, most people prefer not to do it. We do not alkylate our amylenes at the moment.

(2013) Question 29: What are the industry practices to take samples around high-pressure equipment which contain light hydrocarbon and H2S? How do you ensure the samples are handled safely and representative of sample stream?

Our Corpus Christi and Pine Bend refineries had standardized on Texas Sampling Incorporated samplers. They provide a variety of closed loop captured sample systems. We have a Sampler Selection Procedure Flowchart that helps us walk through ‘yes’ or ‘no’ decisions considering high RVP (Reid vapor pressure) material, high-pressure material, high temperature material, high H2S (hydrogen sulfide) options, and plugging potential.

(2013) Question 30: What are your design practices for reactor skin thermocouple requirements in a hydrotreater and a hydrocracker for startups and safe operation?

Our minimal requirement for a hydrotreater is three skin thermocouples at the top and bottom heads of the reactors and a full skin thermocouple at the bottom shell of the reactor just about at the tangent line. The option now is a full skin thermocouple at the top of the shell and the middle of the shell.

(2013) Question 74: How effective are the following decoke methods in a delayed coker furnace: online spalling, mechanical pigging, and steam air decoking?

The way the panel decided to answer this question was for me to give an overview of the different methods and a few of the pros and cons. Then one of the other panelists will present his actual experience. The mechanical method employs metal studded pigs which are pushed in water.

(2013) Question 75: What are the potential problems or negative impacts of utilizing FCC slurry/decant oil as coke drum OH (overhead) line quench oil?

Again, FCC slurry/decant oil has a similar distillation range to HCGO but a higher endpoint. Although it could possibly be used as just overhead quench, we caution that if the slurry/decant oil is not be filtered properly, it will contain catalyst fines that could accelerate the coke deposition by settling in equipment or piping.

(2013) Question 76: What has been the industry experience in mitigating the impact of solids in the feed or coke fines in the fractionator side draws and recycled cutting water?

We use settling mazes in the water section to minimize fines without chemical injection, and then we vacuum out individual cells on a periodic frequency to recover the fines.

(2013) Question 77: What are the consequences associated with continuing to operate the FCC without main fractionator bottoms cooling circulation?

We considered this question as three parts: What is the action to follow in the event of a loss of bottoms’ cooling? What is the consequence if you lose the net slurry product? What are the operational possibilities if you have a well-planned outage of the slurry circuit? In situations one and two where you have lost circulation or you have lost the net bottoms’ product in the system here, we expect that you would shut down the unit consistent with your licensure’s emergency shutdown procedures.

(2013) Question 78: What procedures (maintenance and operational) are being used to minimize risk when swinging the blind between the reactor/main fractionator?

There are two scenarios to consider: shutdown and startup. I will address the shutdown scenario first. For the shutdown scenario, catalyst is de-inventoried from the reactor and regenerator systems, and the main column and reactor are cooled down to 350°F. There are certain operational conditions that must be satisfied before the blind is installed.

(2013) Question 79: How do you mitigate the risk of falling coke deposits from the reactor plenum chamber and vapor line during initial vessel entry?

We have not had the experience of falling coke deposits on vessel entry. We usually experience difficulty in removing the coke deposits, and we do this by mechanical means. Prior to entry into the reactor, a visual inspection is made from the manway. It is typical to see stalactites from the reactor plenum.

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