Turbidimetric-Refractive Index Method for Asphaltene Stability
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Solution Overview
Problem
Existing methods for determining solubility parameters of streams containing asphaltenes are inaccurate, particularly for light crude oils with low asphaltene content and heavy refinery residuals, and fail to accurately assess the impact of fluxants like refinery distillates on solubility parameters.
Innovation Solution
A method combining turbidimetric detection of asphaltene flocculation with refractive index measurements to determine solubility blending and insolubility numbers, allowing for direct and accurate assessment of stability reserve in various process streams, including those with low asphaltene content, by measuring refractive index at flocculation onset and redispersing precipitated asphaltenes in a solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional solubility parameter determination methods are used, then the measurement process is simple, but the accuracy is insufficient especially for light crude oils with low asphaltene content and heavy refinery residuals
Solution Approach 1:
The patent combines turbidimetric detection method and refractive index measurement method into a joint measurement system. The turbidimetric method detects asphaltene flocculation onset while the refractive index provides solubility parameter data, and their results are integrated to determine both solubility blending number and insolubility number simultaneously, improving measurement accuracy for diverse stream types without requiring separate complex procedures
Solution Approach 2:
The patent introduces a turbidimetric detection system as an intermediary to identify the precise flocculation onset point, which then guides the refractive index measurements. This intermediary detection mechanism enables accurate determination of solubility parameters by establishing the exact point where asphaltene precipitation begins, serving as a critical reference for subsequent solubility calculations
2Measurement precision
If refractive index alone is used to measure solubility parameter, then the measurement is straightforward, but it cannot directly and accurately estimate the stability of thermally cracked streams
Solution Approach 1:
The patent merges refractive index measurement with turbidimetric flocculation detection to create a comprehensive stability assessment system. The refractive index provides solubility blending number while turbidimetric detection identifies flocculation onset, and combining these measurements enables direct calculation of stability reserve (SB/IN ratio) for thermally cracked streams, maintaining operational simplicity while significantly improving accuracy
3Adaptability or versatility
If classic techniques are used for solubility parameter determination, then the procedure is well-established, but they are limited and inaccurate for certain stream types such as light crude oils and heavy refinery residuals
Solution Approach 1:
The patent develops a universal measurement system that functions across diverse stream types including light crude oils, heavy refinery residuals, and thermally cracked streams. The joint turbidimetric-refractive index method adapts to different asphaltene contents and stream compositions, providing accurate solubility and insolubility number determination for all these varied applications through a single integrated approach
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides improved reliability and accuracy in determining solubility parameters, extending their determination to a wider range of streams and enabling precise measurement of stability reserve, even in thermally cracked streams, with reduced errors and enhanced sensitivity.
Implementation Method 1
measuring the refractive index of the process stream, RI and the refractive index at the flocculation onset of the asphaltenes (RIo), wherein the flocculation onset is determined via turbidimetric titration
Implementation Method 2
The refractive index parameter at the flocculation onset, RIo is utilized as a direct measurement of the insolubility number, IN. The refractive index parameter of the stream containing asphaltenes, RI, is utilized as a direct measurement of the solubility blending number, SBo
Data Source
Figure 1
AI summary
A method is provided for determining the solubility parameters for a process stream via the joint use of turbidimetric detection of asphaltenes flocculation, which is used to determine and detect the onset flocculation of asphaltenes of the process stream, and a refractive index to determine the process stream solubility parameters such as the solubility blending number and insolubility number.