Caustic Sulfur Extraction Control Using Rich Stream Sensing

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Solution Overview

Problem

Current sulfur removal processes in petroleum refining and petrochemicals face challenges in accurately monitoring and adjusting operations due to reliance on off-line laboratory analysis and qualitative manual tests, which are inefficient and prone to interference from contaminants, particularly when focusing on the lean caustic stream.

Innovation Solution

A process that obtains and compares data from both the rich and lean caustic streams to recommend adjustments in operating conditions, such as caustic flow rates, catalyst amounts, and oxidation unit temperatures, using sensors and a controller to ensure effective sulfur removal from hydrocarbon streams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If off-line laboratory analysis is used to measure mercaptide concentration in lean caustic stream, then measurement can be performed, but the analysis is difficult to run and may be done too infrequently

Engineering Contradiction:

Improvemercaptide concentration measurementVSAvoidanalysis frequency

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces complex off-line laboratory mechanical/chemical analysis methods with an optical measurement system using a probe that transmits light through the caustic stream and detects mercaptide concentration based on light absorption characteristics, enabling rapid in-line measurement

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an optical probe as an intermediary device that interacts with the caustic stream to extract measurement information without requiring direct chemical analysis, allowing for frequent and easy measurements

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If manual test is used to measure mercaptide concentration, then the test can be performed at the unit, but the results are very qualitative

Engineering Contradiction:

Improvetest availabilityVSAvoidconcentration measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces subjective manual testing with an optical measurement system that provides quantitative concentration data based on light absorption spectra, transforming qualitative observations into precise numerical measurements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If electrode system is used to measure mercaptide concentration, then measurement can be performed, but it has limitations and only applies to mercaptides

Engineering Contradiction:

Improvemercaptide measurement capabilityVSAvoidmeasurement applicability range

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal optical measurement system that can detect multiple sulfur species including mercaptides, disulfides, and other sulfur compounds by analyzing their distinct optical absorption characteristics, replacing the specialized electrode system with a multi-functional probe

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If data from lean caustic stream is used to monitor operations, then current processes can operate, but the data is susceptible to interference from contaminants

Engineering Contradiction:

Improveprocess monitoring capabilityVSAvoiddata accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent inverts the traditional monitoring approach by measuring mercaptide concentration in the rich caustic stream (before oxidation) rather than in the lean caustic stream (after oxidation), where the measurement is less susceptible to interference from contaminants and oxidation byproducts

Inventive Principle:

Principle #13The other way round (Inversion)

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 allows for more accurate and efficient adjustments to sulfur removal processes by minimizing interference from contaminants and providing real-time data for optimizing caustic stream operations, leading to improved sulfur extraction efficiency.

Implementation Method 1

extracting sulfur compounds with a caustic stream from a hydrocarbon feed stream to provide a treated hydrocarbon stream and a rich caustic stream

Methodology Applied

Scientific EffectLiquid-liquid extraction: Liquid-Liquid Extraction

Implementation Method 2

oxidizing the sulfur compounds in the rich caustic stream in the presence of a catalyst to provide a lean caustic stream

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11898103B2Systems and process for controlling a sulfur extraction from a hydrocarbon stream

Publication Date: 2024.02.13 UOP LLC

AI summary

Systems and processes for removing sulfur compounds from a hydrocarbon stream. Sulfur compounds are extracted from a hydrocarbon feed stream with a caustic stream to provide a treated hydrocarbon stream and a rich caustic stream. The sulfur compounds in the rich caustic stream are oxidized in the presence of a catalyst to provide a lean caustic stream. The lean caustic stream is returned to extract sulfur from the hydrocarbon stream. Data such as a concentration of sulfurs species and degree of caustic saturation with the sulfur species in the rich caustic stream may be provided by a sensor, compared against other real-time or historical data and used to provide a recommended adjustment to process conditions associated with an extraction unit, or an oxidation unit, or both.