Oxygenated Gasoline Certification via BOB Empirical Modeling
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Solution Overview
Problem
The challenge in manufacturing ethanol-containing gasoline is the variability in properties due to ethanol's water solubility, leading to regulatory compliance issues and increased manufacturing costs, as precise control over blending is difficult when ethanol is added at a distant location from the refinery.
Innovation Solution
A method using online process analyzers to establish an empirical relationship between the properties of the BOB stream and the final oxygenated gasoline, allowing for certification based on predicted values and reducing the need for complex chemometric models, ensuring compliance and minimizing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ethanol is blended at a distant location from the refinery, then water contact is avoided during transport, but precise manufacturing control is lost and specification compliance becomes difficult
Solution Approach 1:
The patent establishes an empirical relationship between BOB properties and final oxygenated gasoline properties before blending occurs. This preliminary modeling allows the refinery to predict final product specifications based on BOB measurements, enabling precise control even when ethanol is blended at a distant terminal location.
Solution Approach 2:
The patent uses measured BOB properties as feedback to adjust blending operations. By continuously monitoring BOB composition and using the empirical relationship to predict final product properties, the system can provide feedback control to ensure specification compliance despite the distributed blending approach.
2Reliability
If BOB specifications include a margin for error to accommodate oxygenate variability, then specification compliance is improved, but manufacturing costs increase due to wasted expensive blendstocks
Solution Approach 1:
The patent changes the approach from using fixed specification margins to using dynamic predictions based on measured BOB properties. By adjusting the predicted final product properties based on actual BOB composition, the system optimizes blending to meet specifications precisely without requiring excessive margins that would waste expensive blendstocks.
Solution Approach 2:
The patent replaces the mechanical approach of adding fixed specification margins with a predictive modeling system. Instead of physically adjusting blend compositions with built-in safety buffers, the system uses empirical relationships and measurements to predict final properties, allowing for more efficient use of blendstocks while maintaining compliance.
3Measurement precision
If complex chemometric models are used to predict finished gasoline properties, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses simple, robust empirical relationships rather than complex chemometric models. These simpler models are easier to implement and maintain, and the patent accepts slightly reduced precision in exchange for significantly reduced complexity, making the system more practical for routine industrial use.
Data Source
AI summary
A method for controlling the manufacture and certification of an oxygenated gasoline product is carried out by manufacturing a gasoline Basestock for Oxygenate Blending (BOB) at a refinery site in accordance with an empirical relationship, valid for at that site under typical manufacturing conditions, between (i) a property value of the BOB stream such as octane as determined by an on-site online process analyzer and (ii) the corresponding instantaneous value or FPAPV property value as determined by the test method mandated by the product specification for the final gasoline stream when blended with the required proportion of oxygenate. The quality of fit of this empirical relationship is calculated according to the standard deviation of the residuals of the relationship and a confidence level is fixed so that the final oxygenated gasoline formulated with the BOB will meet the required property specification when measured by the test method mandated by the specification. The final oxygenated gasoline blend is certified as having a property value conforming to the required specification based on the predicted property value for the finished gasoline.