Process engineers face many technical challenges and, while we can solve some of these problems, others must simply be managed safely. My first technical project was to determine a solution to a liquified natural gas (LNG) plant’s slop-oil disposal problem.
The facility’s slop-oil tank was overflowing, causing environmental damage. The original design called for slop-oil incineration, but the incinerator was not functioning, so the slop-oil was trucked to a nearby crude-oil loading facility. This method was unreliable and the tank sometimes overflowed.
During this project, I learned some valuable lessons, which I share here. I continue to revisit these same lessons as I face more-complex problems.
First, look to past solutions
In a meeting with the operations team, an engineer raised the idea of spiking slop-oil into the LNG condensate as an alternative disposal method that would be reliable and safe. Spiking slop-oil into condensate could also generate additional revenue, as it could then be sold at the price of condensate. The team decided to explore this alternative, and I volunteered to determine how much slop-oil we could add while still meeting the condensate specifications.
The engineer who proposed this solution knew it had been used in a similar facility. Before spending time to engineer solutions to technical problems, find out if such problems have occurred in the past at your facility or at similar sites, as well as the solutions that were explored. Adapting ideas from past experience is faster and easier than engineering new ones. However, ensure that the adaptation meets current regulatory and operational requirements.
Seek to optimize cost
First, I estimated the total annual amount of slop-oil and condensate produced by the facility. Next, I estimated the maximum slop-oil concentration in the condensate if all of the slop-oil produced was added to the condensate. I worked with the lab personnel to obtain samples and run tests on varying concentrations of slop-oil in condensate. It turned out that we could spike all the slop-oil into the condensate and still meet the condensate sales specifications.
This was an economical solution that also reliably and safely solved the problem. A good solution should either be the least expensive, generate the most revenue, or save the most money, while meeting the technical and safety specifications.
Maintain good interdisciplinary relationships
I was excited by the results of my investigations, and my boss and I decided to share the findings with the facility’s sales team. The sales team informed us that meeting the formal condensate specifications was not the only concern. The condensate was typically sold to refineries and chemical plants that used it to produce precursors for plastics production.
Any trace heavy metals contaminants from the lube oil could poison the catalysts and cold-box heat exchangers of our customers’ crackers over time. While a few cargos might be sold because the condensate met the specifications, the long-term relationship with the buyers could be compromised.
While I did my portion of the work, input from the sales team was required to truly determine whether the solution was viable. Process engineers have to work in multidisciplinary teams that require us to maintain good working relationships. Not only does this help to expedite the problem-solving process, it helps to produce robust solutions.
Document everything
Document everything, even “failures.” I was disappointed when I realized my proposal would not work. However, my boss helped me to see that it was not a failure. We learned that a solution was not feasible in our facility — information we didn’t have before. The company would keep a report on this investigation, precluding a repeat investigation and saving the organization time and effort in the future.
No technical investigation to solve a problem is a failure. While my research did not produce an implementable solution, it did produce valuable knowledge for the organization, which may prevent a future engineer from pursuing an unviable option. Process engineers must learn from solutions that are feasible as well as solutions that are not, and documentation of all options is critical to this process.
Find the root cause
I was still bothered that the original problem had not been solved. If no solution was found and implemented, the slop-oil tank would overflow again. I returned to the problem definition and discovered that the real problem was not the slop-oil tank overflowing, but the unreliability of the slop-oil evacuation. I dug even deeper to discover the root cause included inadequate communication and scheduling with the crude oil facility receiving the slop-oil. Before attempting to solve any technical problem, process engineers should first define the problem and its root causes.
I recommended improving communication between our facility and the crude oil facility to enhance the reliability of the evacuation process. I also recommended that our facility not spike slop-oil into condensate. I prepared my report and properly closed out the technical investigation.
This article originally appeared in the Career Connections column in the July 2019 issue of CEP. Members have access online to complete issues, including a vast, searchable archive of back-issues found at aiche.org/cep.