According to Earl Crochet, director of engineering and operational optimization at Kinder Morgan Terminals, a discussion of how best to maximize storage tank space begins with one simple — or, perhaps, not so simple — question: How full is full?
“The answer quite often depends on how you ask the question,” Crochet said. “Are you talking about maximum working levels? If you tell business development you’ve got a 150,000-barrel tank, they’re going to sell at least 150,000 barrels to a customer.”
“The problem is, if you call a tank builder and say you want a 150,000-barrel tank, you’re not going to get a 150,000-barrel capacity,” Crochet observed.
Depending on how the individual tank is designed, he explained, “you may very well be down to 130 or 135, if you’re lucky.”
Fullness, Crochet said, may be defined as percentage of capacity, reaction time or “some arbitrary number.” Addressing delegates at the 11th annual National Aboveground Storage Tank Conference and Trade Show held recently in Galveston, Texas, Crochet shared that his company once bought a facility where there was a very high number of tanks — “into the triple digits.”
“Every tank was set at the exact same footage from the top, with no technical consideration of the flow rates and no consideration of anything,” he said. “I would not advise that.”
Risk is also a consideration when assessing fullness.
“Risk, like a lot of things, is very, very personal,” Crochet said. “You can create numbers, but the reality is it is a very personal thing. Different companies see risk differently. We’re talking about loss of money, loss of impacts and a whole lot of stuff.”
But how big is big?
A prime aspect of maximizing capacity, Crochet said, is knowing the tank’s fill rate and how quickly product is being transferred into the tank.
“From an optimization standpoint, it’s how fast the level is going up,” he said. “That may seem obvious to a lot of people but, again, a lot of people don’t get this. But if you think about it, it makes perfect sense. If you’ve got a skinny, tall tank, and you’ve got a big, fat, wide tank with the same volume, the same flow rate is a lot worse in the skinny, tall tank because it’s so many barrels per foot or gallons per inch.”
That consideration matters, Crochet explained, “because you can have two identical flow rate volume tanks, but depending on how they’re configured, your reaction and response time can be completely different. That’s what you’ve got to worry about.”
As the industry’s technology continues to advance and change, the possible loss of technology in operations must also be considered, Crochet said.
“If you can’t operate without technology, that’s OK, but your procedure needs to say that,” he said.
Procedures must be precise, detailed and understandable, Crochet said, warning against using vague terminology like the word “big.”
An experienced operator who has been with a company for many years, he said, may understand what his or her manager means by “big,” but not everyone will.
“Every company has its own history, culture and definitions. But what about the new guy you just hired?” he asked. “He has no idea what ‘big’ is.”
Ultimately, managers must consider all modes and situations, Crochet stressed, reminding conference attendees to consider abnormal operations at their facilities, accounting for factors like possible elevation differences and how that impacts tank levels.
Abnormal operations, he said, are often overlooked or are insufficient. Referring to Murphy’s Law, Crochet quipped, “Murphy was an optimist.”
“Things that can happen will happen,” he concluded. “You’ve got to figure out all the potential things that can go wrong and how to stop them.”
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