2020 AFPM Summit: Is it time to redefine performance to improve operations and profit?
Is it time to redefine performance to improve operations and profit?
JEFFREY ZURLO, SUEZ – Water Technologies & Solutions
It is unfortunate that several important factors influencing the ease of processing a crude oil—or more commonly a mixture of several crude oils in an often-changing matrix of composition—are not measured as part of an oil’s specification. Factors such as level and type of contaminants, blended asphaltene compatibility, solids and more, are either not considered at all, or are determined either by observation in the moment or lab testing where results are available only after the moment of processing. Further, the volatility in crude and product prices and demand are making even the most current production planning, models and operations far from optimized. Our experience with hydrocarbons throughout the oil and gas industry (upstream, midstream and downstream) shows that events like treatments, blending and comingling along the complex path from the oil well to the refinery can often change these factors throughout the production and transport process.
However, using modern equipment, sensors and techniques to measure factors affecting the processing of crude oils in ways not available even a decade ago, along with a willingness to look at performance differently, opens the door to challenging the traditional definitions of good performance and extends safe operating limits.
Changing the look of crude overhead corrosion control. Consider crude distillation column overhead corrosion control. As a result of traditional, relatively infrequent, manual and long lead-time measurements, overhead system operations are often managed using fixed and broad safety margins to ensure natural (but mostly unmeasured) operating variation does not adversely impact corrosion. Not only does this leave profits on the table, but this approach is not very successful in many cases: an analysis report by NACE International states that in the U.S. alone, annual profit losses due to refinery corrosion may be as high as $12 B.
Developments in online sensors/controllers, rigorous and rapid amine measurements tested at the local site, and advancements in data handling and analytics enable dynamic determination of system corrosion potential and current safe operating margin in near real time. FIG. 1 charts the overhead salting potential of a crude unit during two separate operating periods at the same overhead temperature. The green region represents the safe operating window, the red is unsafe, and the yellow is the safety margin for that time period.
FIG. 1. Crude column overhead salting potential.
The left-hand chart shows a period of unsafe operation; it is only in the safe operating window 16% of the time and has wide operating variation (the spread of data points). This leads to a wide safety margin required to ensure safe operation (yellow band). The right-hand chart shows much better performance with tighter operational control and, subsequently, can operate safely with a narrower safety margin. This allows improved operating state visibility and operating closer to the optimum for improved profit potential.
As a result of using this different definition of safe performance, a refiner was able to reduce its overhead column top operation by approximately 25°F (FIG. 2) to increase distillate yield without sacrificing reliability. Due to favorable distillate margins, captured profit was estimated at $1.5 MM/yr.
FIG. 2. Crude column overhead temperature reduction.
Processing opportunity crude oils while improving performance. A U.S. refiner was looking to take advantage of lower-priced opportunity light tight oil (LTO) crude oils to replace a light, sweet crude that made up a significant portion of their blend, but had a rising price tag. The refiner was concerned with possible negative impacts of the new unfamiliar crude oil, as there were already crude unit fouling-related issues. An average of six hot preheat exchanger cleanings during the crude run were required to maintain target production rate, in addition to full hot train cleaning each scheduled unit shutdown.
To help determine the impact of substitution on processing, a recently commercialized technique was deployed using two new tests coupled with advanced analytics to quantify blend compatibility and fouling potential. The tests both quickly “fingerprint” crude oils using IR spectroscopy and separately measure organic and inorganic solids that lead to fouling to develop quantified results previously not measured. It was determined that replacing the traditional crude oil with the LTO would markedly increase both blend compatibility and fouling-related issues (FIG. 3), and identified a significant root cause of fouling related to organic solids deposition. Coupling the current operating challenges related to fouling with this new data, an action plan was developed using chemical treatment mitigation and managed with continued monitoring. A crude preheat anti-foulant program was initiated and the frequency of crude stabilizer injection was increased. Changes in blend compatibility and fouling potential were used to manage injection type and rates.
FIG. 3. Compatibility and fouling test results.
As a result of the new treatment and monitoring programs, the opportunity LTO crude oil was able to completely replace the traditional baseline crude oil blend. At the same time, system performance was markedly improved. Over 95% of fouling in the crude unit was avoided (FIG. 4) and, importantly, preheat exchanger cleanings between unit shutdowns were eliminated. Based on the lower crude oil price, higher heat transfer efficiency, elimination of cleaning cost and avoided rate reductions, the net profit increase was estimated at almost $6 MM/yr after accounting for increased treatment and monitoring costs.
FIG. 4. Effect of treatment on preheat fouling rate.
Takeaway. Progressive refiners are adopting new approaches that combine technology, chemistry and analytics, along with a shift on how performance is measured and defined to expand their operating window, improve reliability and, ultimately, profits. The methods and approaches describe here, while relatively new, have proven effective in the industry over the last several years at multiple refinery locations. SUEZ believes that the answer to the question posed at the start is yes, it is the right time for many refiners to redefine performance to capture the operational and profit advantages.
For more information, visit https://www.suezwatertechnologies.com/products/hydrocarbon-processing/integrated-solutions-refining.
ABOUT THE AUTHOR
JEFFREY A. ZURLO is a Senior Marketing and Commercialization Lead for SUEZ – Water Technologies & Solutions. He has more than 30 years of experience across several hydrocarbon processing technologies in process engineering, technical sales and services, subject matter expertise and strategic marketing. Prior to joining SUEZ – Water Technologies & Solutions in 1997, Mr. Zurlo held various process engineering positions at Sunoco Inc., Koch Refining and Hercules Incorporated. He holds a BE (ChE) degree from Stevens Institute of Technology.