Visbroken Residue Stability Prediction Method

Solution Overview

Problem

Current methods for predicting the stability of visbroken residue streams in refineries face challenges in ensuring adequate solvent power and critical solvent power, leading to potential asphaltene precipitation and fouling issues, especially when blending with cutter stocks.

Innovation Solution

A method is developed to predict the critical solvent power of visbroken residue streams by correlating it with the critical percentage titrant for asphaltene stability in atmospheric residue streams, using a conversion factor and density-based calculations, and adjusting refinery processes to maintain stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If visbreaking severity is increased to improve conversion efficiency, then lighter products yield increases, but asphaltene content increases and solvent power decreases leading to precipitation risk

Engineering Contradiction:

Improveconversion efficiencyVSAvoidasphaltene stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by calculating the P-value before blending operations occur. The method computes the predicted P-value using the formula that incorporates visbroken residue properties, cutter stock properties, and their blending ratios. This advance calculation allows refiners to predict asphaltene stability issues before they occur, enabling preventive measures to be taken rather than reacting to precipitation problems after they arise.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the calculated P-value to guide blending decisions and process adjustments. The method provides a quantitative metric that feeds back into the blending operation, allowing operators to adjust cutter stock selection, blending ratios, or visbreaking conditions to maintain adequate P-values and prevent asphaltene precipitation. This closed-loop approach ensures continuous stability monitoring and control.

Inventive Principle:

Principle #23Feedback

2Temperature

If cutter stocks with low solvent power are used to reduce viscosity, then fuel oil viscosity decreases, but the blend solvent power falls below critical level causing asphaltene precipitation

Engineering Contradiction:

ImproveviscosityVSAvoidblend stability

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by calculating the predicted P-value before blending operations occur. The method computes the predicted P-value using the formula that incorporates visbroken residue properties, cutter stock properties, and their blending ratios. This advance calculation allows refiners to predict asphaltene stability issues before they occur, enabling preventive measures to be taken rather than reacting to precipitation problems after they arise.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies partial or excessive action by requiring the P-value to exceed the minimum threshold of 0.05. Rather than merely meeting the stability requirement, the method encourages maintaining a sufficient margin above the threshold to account for uncertainties and variations in feedstock properties. This excessive action approach ensures robust stability even under varying operating conditions.

Inventive Principle:

Principle #16Partial or excessive action

3Temperature

If blending ratio of cutter stock is increased to meet viscosity specifications, then fuel oil viscosity improves, but solvent power decreases below critical solvent power threshold

Engineering Contradiction:

ImproveviscosityVSAvoidasphaltene precipitation

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by calculating the predicted P-value before blending operations occur. The method computes the predicted P-value using the formula that incorporates visbroken residue properties, cutter stock properties, and their blending ratios. This advance calculation allows refiners to predict asphaltene stability issues before they occur, enabling preventive measures to be taken rather than reacting to precipitation problems after they arise.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the calculated P-value to guide blending decisions and process adjustments. The method provides a quantitative metric that feeds back into the blending operation, allowing operators to adjust cutter stock selection, blending ratios, or visbreaking conditions to maintain adequate P-values and prevent asphaltene precipitation. This closed-loop approach ensures continuous stability monitoring and control.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10794891B2Fuel oil stability

Publication Date: 2020.10.06 BP CORP NORTH AMERICA INC

AI summary

A method for predicting the critical solvent power of a visbroken residue stream of interest, CSPVisRes(OI) comprises predicting CSPVisRes(OI) from the critical percentage titrant of an atmospheric residue stream, CPTAR, the atmospheric residue stream being derived from the same crude oil as the visbroken residue stream of interest. A method for predicting the solvent power of a visbroken residue stream of interest, SPVisRes(OI), comprises predicting SPVisRes(OI) from the critical solvent power of the visbroken residue stream, CSPVisRes, and the critical percentage titrant of the visbroken residue stream, CPTVisRes. CPTVisRes is derived from the critical percentage cetane of the visbroken residue stream, CPCVisRes, which, in turn, is calculated from the P-value of the visbroken residue stream. The methods may be used to predict the stability of a fuel oil containing the visbroken residue.