Maximizing Benefits through Advanced Process Control (APC) in Gasoline Blending


Advanced process control (APC) plays a crucial role in real-time analysis and recipe control for optimizing gasoline blending operations. However, to harness the full potential of these systems, users must be aware of key considerations. This article will explore three important caveats when implementing APC in gasoline blending: configuring the objective function, ensuring accurate parameters and constraints, and establishing a robust performance review process. By addressing these aspects, refineries can unlock the benefits of precise process control, automation, and financial advantages while adapting to lean operational environments.


Table of content:

Configuring the Objective Function

Parameters and Constraints

Performance Review Process

Benefits of a Well-Configured APC System



Configuring the Objective Function:

To achieve optimal results, configuring the APC system’s objective function is essential. Refineries must customize the solution to align with their specific refinery posture and economic goals. Often, default settings from initial installation are utilized without considering individual circumstances. Refineries should assess and update these settings regularly to maximize performance and value delivery.


Parameters and Constraints:

The accuracy and timeliness of data feeding into the APC system are critical for effective gasoline blending. Refineries must ensure that data sources are up-to-date, reflecting daily operations and incorporating the latest lab data. Careful attention should be given to the calibration and accuracy of the data. Additionally, refining the constraints is vital to strike the right balance. Overly flexible constraints can lead to excessive fluctuations during adjustments, while overly tight constraints may hinder the system’s ability to provide optimized solutions.


Performance Review Process:

Regular performance reviews are essential to ensure that the APC system remains up-to-date and continuously improves. Refineries should establish a robust review process to assess the system’s configuration and identify additional optimization opportunities. By periodically evaluating system performance and exploring new features, refineries can enhance their operational efficiency, identify potential areas for improvement, and capitalize on emerging technologies.


Benefits of a Well-Configured APC System:

A well-configured APC system in gasoline blending brings numerous benefits. It enables precise process control, ensuring the production of optimal-quality gasoline within specifications. The high level of automation reduces manual intervention and empowers process control engineers and operators. In lean operational environments, a well-configured APC system can generate significant financial benefits, potentially amounting to tens of millions of dollars annually.



Maximizing the benefits of APC in gasoline blending requires careful attention to key considerations. Configuring the objective function to align with refinery goals, ensuring accurate parameters and constraints, and implementing a robust performance review process are crucial steps. By addressing these caveats, refineries can achieve precise process control, automation, and substantial financial advantages in an increasingly lean operational landscape.

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How to Establish a Good Ethanol Uplift Model?

“How to establish a good ethanol uplift model?” has been a common question when it comes to gasoline blending. With the addition of 10% ethanol to a majority of gasoline products, accurate prediction of the final fuel properties is critical to mitigate margin erosion. With years of experience in blending optimization projects, at Trindent we have developed specific expertise in this area, and here are some insights:


Ethanol Uplift Model Best Practices

Each refinery has its configurations that are developed as a result of the molecules they are making. Therefore, picking the right independent variables to start the development of the model is critical. It starts with understanding the principle of what Octane Number (ON) is, and how this property is related to the chemical molecules inside the gasoline. Typically, a refinery can use as much as 7-8 independent variables, and around 10-15 iterations before finding the perfect model which is not only accurate but also intuitive. The complexity of the model is also important as you want to make it sophisticated enough to provide the accuracy you want, but also simple enough to integrate into the existing system with ease.


Managing Component Distribution

Once a model is developed – the next question would be – how do we optimize it? In addition to adjusting the ON of the neat blend stock (which is often the only approach most refineries take), refineries may take advantage of other property and compositional requirements between to maximize the overall benefit of ON uplift.


Going Beyond ON

While a lot of focus on the ethanol model is about ON, it is imperative to consider other properties that are also affected by ethanol. Therefore, a mature ethanol model system would consider other key properties such as RVP, distillation, and V/L. A good ethanol model system would allow a refinery to achieve method repeatability level giveaway for all their constrained parameters and maximize the benefit from production cost management.


This article was written by KAI Y. WAN, an Associate Principal at Trindent Consulting. Dr. Wan has collaborated closely with multiple business partners in the energy sector across North America and Asia-Pacific, including some of the world’s largest refineries, and has delivered > $300 MM in financial improvements, with typical project ROIs at 500%–1,500% during the first year after implementation.

How Does Butane Affect Gasoline Blending?

Butane is one of the most important components in gasoline blending and arguably one that could provide the most economic benefit to the bottom line of more and more skinny refinery margins. Butane has a high octane and high RVP which makes it the ideal component to improve the quality of gasoline blends, especially in Winter months. Along with its properties, it has a relatively low cost compared with other components making it the go-to ingredient when blending gasoline. Moreover, it could help companies to reduce the product quality giveaway, i.e. the difference between the specification and the actual product properties. It is estimated that each barrel of butane added to the gasoline blend represents an uplift of $40-50 of the final product.


Factors Influencing Butane Utilization

The management of butane is as important as the product itself considering the relatively large amount of product that is required during blending. To improve how well the butane is utilized, the following factors should be considered:

  • Inventory capacity
  • Sourcing: Internal production vs. external supply
  • Product monitoring


The goal is to have enough butane available when blending in order to optimize the gasoline recipe, minimize giveaway and improve margins.


Inventory capacity: Consider doing a mass balance of butane not only for each blend but for an entire season (mainly Winter) to understand the total amount that will be required. It is recommended to include all the available tanks (accumulation), estimated gasoline production and butane percentage (out) and product sourcing (in). For perspective, butane represents about 10% of the total gasoline volume in wintertime, which is 4-5 times more than in summer.

Sourcing: After the total requirement of butane is determined, an important question has to be asked regarding its source: Is the refinery able to produce the total amount needed? Or does an external supplier need to be involved? If so, how often can you get the product? How soon in advance does the request need to be placed? How feasible is it to have an additional volume? How is the quality of the product and how to monitor it? Planning for the butane sourcing is recommended prior to the season to avoid last-minute pitfalls and secure steady availability through the season.

Product monitoring: This is one of the most critical factors to consider when managing butane – to be able to know the product location, quantity and quality at any given time. The information should be transparent and encompass all the stakeholders including butane storage levels, requirements for blending and other processes, internal movement of product, etc. so that decisions can be made promptly without bottlenecks. Data visualization tools are very important in order to convey information in the most efficient way possible. It is recommended to generate automated data without any additional effort.


Once the analysis is done all stakeholders must come up with a plan to address the weak points, generate solutions, and implement and track them. They can use this analysis to evaluate the outcomes for future seasons or expand to other processes or locations as needed. A combination of technical and managerial expertise is fundamental for excellent butane management in order to understand common problems, physical limitations, product specifications/components properties, and data manipulation. This further helps in engaging with the multi-function teams at different levels, motivating and coaching employees, and providing tools to effectively track results.