Steam Cracker Naphthenic Acid Conversion

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Solution Overview

Problem

High Total Acid Number (TAN) crudes pose challenges in refining due to corrosion issues and reduced value, with existing methods requiring costly treatments or separate heating steps, which are inefficient and energy-intensive.

Innovation Solution

Directly introducing high TAN feedstreams into a steam cracker pyrolysis unit, where naphthenic acids are converted to CO, CO2, and low molecular weight acids, without the need for heat-soak or chemical treatments, and optionally flashing to remove heavies, allowing for efficient production of olefins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high TAN crudes are subjected to conventional refining treatments (desalting, distillation, chemical neutralization), then corrosion problems can be mitigated, but process complexity and treatment costs increase significantly

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidrefining process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes naphthenic acids from the crude oil feedstock before steam cracking through a specific treatment process. This separation of the harmful acidic component allows the remaining feedstock to be processed in the steam cracker without causing corrosion damage to equipment, thereby resolving the contradiction between corrosion resistance and process complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful naphthenic acids into a beneficial product stream by treating them in a separate unit where they are transformed into usable chemicals or fuels. This conversion turns the previously harmful acidic components into valuable products, eliminating the need for complex neutralization treatments while maintaining equipment integrity.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Quantity of substance

If separate heat-soak treatments are applied to reduce TAN before steam cracking, then acid content decreases, but energy consumption and processing time increase

Engineering Contradiction:
Improvenaphthenic acid contentVSAvoidenergy consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent merges the acid removal treatment with the existing steam cracking process by integrating a treatment unit that operates concurrently with the cracker. This combined approach allows acid removal and olefin production to occur in an integrated system, eliminating the need for separate sequential heat-soak treatments and reducing overall energy consumption.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the operational parameters of the treatment unit to operate at temperatures and residence times that are more efficient than conventional heat-soak methods. By optimizing these parameters, the process achieves effective acid removal with lower energy input and shorter processing time, resolving the contradiction between acid content reduction and energy consumption.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If chemical additives are used to neutralize acidity in steam cracked products, then corrosion is reduced, but additional processing steps and costs are required

Engineering Contradiction:
Improveequipment durabilityVSAvoidprocessing efficiency
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary treatment to the crude oil feedstock before it enters the steam cracker, removing naphthenic acids in advance. This preliminary action prevents corrosion from occurring in the first place, eliminating the need for subsequent chemical neutralization steps and additional processing equipment, thereby improving both reliability and processing efficiency.

Inventive Principle:
Principle #10Preliminary action

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 process effectively reduces naphthenic acid content in products, avoiding costly treatments and energy-intensive steps, while maintaining product quality, and allows for the production of valuable olefins from high TAN crudes without additional refining steps.

Implementation Method 1

feeding high TAN feedstreams to a steam cracker, whereby naphthenic acids in the feedstreams are substantially converted to CO, CO2, and low amounts of lower molecular weight acids

Methodology Applied
Scientific EffectPyrolysis: Pyrolysis

Data Source

PatentUS8277639B2Steam cracking of high TAN crudes
Publication Date: 2012.10.02 EXXONMOBIL CHEMICAL PATENTS INC

AI summary

The invention is directed to a process comprising feeding high TAN feedstreams to a steam cracker, whereby naphthenic acids in the feedstreams are substantially converted to CO, CO2, and low amounts of smaller acids (e.g., formic, acetic, propionic, and butyric acids). The feedstream is preferably a high TAN feedstream comprising crude or high TAN feedstream which has previously been subjected to a refinery process to remove resid.