How to address optimization constraints without shutting down

The industry’s brightest engineers are adopting process optimization strategies to solve refinery and chemical plants’ costliest challenges.

Image: NARL Refinery

The start of 2019 was a rough start for the refining industry. Poor gasoline cracks were driving margins into negative while favorable distillates were helping to stay close to or a bit better than break-even.

Refining margins

Cracking margins for making gasoline along the U.S. Gulf Coast alone hit their lowest levels since 2014 in February before recovering a bit in early March, the U.S. Energy Information Administration (EIA) said.

The gasoline crack spread is the difference between the spot prices of gasoline and crude.

In such a challenging time, maintaining up-time for a refinery is crucial. At the same time, refiners cannot afford high value product yield deterioration.

This necessitates interim solutions and online fixes that maintain or improve distillates yields.

Unplanned outages are challenging and can easily overrun a refinery’s annual budget by millions.

Process optimization case study

When a plant has a known problem that will need a shutdown to fix, implementing a low-cost project that can reduce the severity of the problem can minimize economic impact significantly while waiting for right opportunity to fix the root cause.

This strategy helped North Atlantic Refining (NARL) regain its high value distillates yield at a refinery by ~2% which is equivalent to $12.8 million, Jaydip Bhadaliya, Manager of Business Optimization for NARL Refining explained.

“It is important to analyze process constraints closely before concluding if those are real constraints,” Bhadaliya said. “Possibly there are a few unexplored process optimization solutions that can help reduce the severity of the process problem.”

At North Atlantic Refining, the team was challenged by deteriorating performance of its crude atmospheric distillation tower that mainly affected Diesel – AGO separation, Heavy Straight Run Naphtha and Kero separation leading to loss of distillates yield and increased front end in the hydro-cracker feed.

The root cause of the problem was fouling of the naphtha splitter reboiler which is run by Diesel pump-around.

“The solution was obvious, clean the reboiler. But this required shutting down of either entire crude unit or part of the crude unit with significant slops generation,” Bhadaliya said.

Until turnaround of the crude unit or the earliest available opportunity to clean the reboiler, NARL Process Tech Services worked out an interim alternative of recovering diesel.

“Quality of Atmospheric Gas Oil (AGO) could be adjusted in the crude distillation tower and same could be then routed into the Diesel Hydro-Treater (DHT)” Bhadaliya said.

The refinery didn’t have readily available piping to route AGO into the DHT. However, the team figured out that installing piping online was feasible and in fact was a small project.

It took two weeks for the projects team to engineer, construct and commission the new piping.

“This helped the refinery restore high value distillates yield by ~2% which is equivalent to $12.8 million a year in savings or margin boost,” Bhadaliya said.

This was accomplished without shutting down the unit.

“If the decision to shutdown would have been the shortlisted option, refinery could have incurred exorbitant cost of about $14 million in maintenance and lost processing opportunity,” Bhadaliya said.

For facilities like a petroleum refinery, up time and optimized runs are critical.

“The optimization ideas and opportunities which can only be implemented during shutdowns/turnarounds are important for long term sustainability,” Bhadaliya said. “But at the same time, addressing constraints while maintaining up time of the processing units not only prevents losses but helps maximize profitability.”

Sharing Experiences

Every refinery is unique and process engineers come up with variety of simple to complex solutions to troubleshoot optimization constraints and get the most out of their kit. It is quite possible that one plant may be working to resolve something that would have already been history for the other one. Therefore, collaboration and sharing of experience can help save time and efforts. The same is true when it comes to the application of new concepts in the refining industry.

“More references of successful implementation drive others to follow the trend as the risk factor is then minimized,” Bhadaliya said. “Therefore, sharing of success stories on a common platform will help overcome process engineering challenges.”

New challenges

For refinery process engineering trends, the processing of shale crudes and limited industry experience with the potential impact on the process equipment is another challenge the industry is grappling with. But in sharing these success stories, Bhadaliya believes the industry can be much more effective.


Another area where engineers can work together on is technology. Refineries already have some level of digitalization, automation and data analytics implemented for basic functioning, but this can be improved.

“Refineries generate massive data from their day to day operations, control systems, laboratory analysis, planning and scheduling, and maintenance planning functions,” Bhadaliya said.

Environmental regulations

Historically, environmental regulations have driven innovations in the refining industry.

“Changes in fuel specifications is a good example. We expect to witness the same with the IMO 2020 low sulfur bunker fuel specs implementation,” Bhadaliya said.

The refining industry is faced with an uncertain and volatile market. New challenges as well as new opportunities will be posing itself time to time.

“We can overcome all of these challenges by building process experience and sharing the same with peers,” Bhadaliya said.

  By Heather Doyle

Overcoming and solving major engineering, construction, supply chain and workforce challenges will be a key theme of the Downstream 2019 event.

In its 4th year and bigger than ever, the Downstream 2019 event will be held June 11 and 12 at the George R Brown Convention Center in Houston, Texas.

The conference team is expecting more than 7,000 exhibition visitors, 3,000 conference visitors, 350 exhibition booths, alongside hundreds of strategy panel sessions and technical sessions.

This year, Downstream 2019 adds two new sections to its list of dedicated conference tracks. Process Engineering and Workforce Development will be added to the traditional tracks: Major Projects, Small to Midsize Projects, Shutdowns and Turnarounds, and Reliability and Maintenance.

Visit the conference website to discover more today!