Predictive model for maximum feedstock flexibility (ERTC 2023)
Challenge of crude oil variability. Current market conditions are driving refineries towards a permanent diversification in crudes. Crude oil is a complex mixture containing many compounds with a variety of structures.
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Asphaltenes, high molecular weight cyclical polar compounds, are usually not soluble in crude at a molecular level. They exist as micelles in solution. Resins, having a highly polar end with an alkane tail, are adsorbed onto the asphaltene micelles, creating a stable colloidal solution.
Changes in pressure, temperature, and composition may affect the asphaltene-to-resin ratio of a crude blend, depleting the compounds that help keep asphaltenes dispersed. Precipitation of asphaltenes and high molecular weight aliphatics from these phenomena is commonly referred to as ‘incompatibility’. It can increase the stability of emulsions at the desalter, as well as contribute to downstream fouling.
What is CrudePLUS?
The CrudePLUS Service is a refinery sustainable service to grow profitability, increase reliability, improve safety, and enhance environmental compliance. From the time crudes are purchased through their processing in a refinery, CrudePLUS provides actionable insights to improve successful crude processing.
The CrudePLUS Service provides processing insights that traditional crude assays or typical traditional titrating stability tests can not. It utilises the power of advanced in-the-field rapid-response analytical testing via an Oil Fingerprinting & Solids Testing System coupled with proprietary predictive modelling software (see Figure 1).
Within minutes, important information on crude and crude blends can be attained, providing operations with the feed-forward information necessary to reduce the risk of downstream upsets, to control desalter interface build-up, mitigate the risk of desalter effluent contaminants impacting the wastewater plant, and minimise energy demand by reducing fouling of heat exchange equipment.
The system accurately and reliably predicts the instability/incompatibility and fouling potential of crude oils, slop oils, other refinery fluids and their blends.
CrudePLUS Core Characteristics
The major elements of CrudePLUS are:
● Relative Instability Index (RIX): RIX is a key parameter that quantifies the potential capacity of a fluid to self-destabilise or to destabilise other fluids in a blend (incompatibility) relative to a stable and proprietary benchmark. It classifies the tested fluid into severity regions
● Crude Precipitant Index (CPI): CPI provides a measure of the relative potential precipitant amount upon destabilisation of asphaltenes and other related colloids in the fluid. CPI is a function of RIX and the level of available precipitants (asphaltenes and other colloids)
● Blending order: The order in which two or more fluids are blended has a direct impact on the actual degree of incompatibility and precipitant amount.
● Fouling Potential Index (FPX): FPX quantifies fluid fouling potential and classifies it Into one of five severity regions.
While the paths, phases, and strategies to ultimately mitigate and capture maximum value from all identified opportunities will vary from refinery to refinery, there are three possible, not mutually exclusive scenarios under which a refiner may decide to use CrudePLUS to maximise value generation (see Figure 2).
Working towards and attaining the point of maximum value requires the engagement and support from other refinery groups beyond operations and process engineering, such as economics planning and scheduling and crude purchasing.
CrudePLUS is a trademark of Veolia and may be registered in one or more countries.
This short article originally appeared in the 2023 ERTC Newspaper, which you can VIEW HERE
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