Antifoulant Additive for Caustic-Induced Fouling in Delayed Coking Furnaces
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Solution Overview
Problem
Delayed coking unit furnaces experience reduced run length and fouling due to caustic carryover from desalter units, leading to unscheduled shutdowns and decreased refinery profitability, as existing antifoulants do not effectively prevent caustic-induced fouling without reducing operational severity.
Innovation Solution
An antifoulant additive comprising naphthenic acid, petroleum sulphonate, phosphate ester, and gasoil is used to neutralize caustic compounds, converting them into a benign naphthenate form and reducing fouling tendencies, preventing furnace tube fouling without reducing operational severity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If caustic compounds are dosed in the desalter unit, then desalting effectiveness is improved, but caustic carryover into the crude oil increases causing furnace tube fouling
Solution Approach 1:
Naphthenic acid acts as an intermediary substance that reacts with caustic compounds to form benign naphthenate salts. This mediator approach allows the desalter to continue using caustic for effective desalting while the naphthenic acid neutralizes any caustic that carries over into the crude oil, preventing furnace tube fouling.
Solution Approach 2:
The naphthenic acid is dosed in advance to preemptively neutralize caustic compounds before they can cause fouling in the furnace. This preliminary anti-action occurs in the feedstock preparation stage, preventing the harmful effect before it manifests in the furnace system.
2Object-affected harmful factors
If operational severity of the delayed coker unit is reduced, then furnace tube fouling is decreased, but product yield and refinery profitability deteriorate
Solution Approach 1:
The harmful caustic compounds that cause fouling are converted into beneficial naphthenate salts through neutralization with naphthenic acid. This transformation allows the system to maintain high operational severity for maximum product yield while the converted harmless substances prevent fouling, effectively turning the fouling problem into a benefit.
3Object-affected harmful factors
If conventional antifoulants are used, then general fouling is reduced, but they do not effectively prevent caustic-induced fouling
Solution Approach 1:
The invention changes the chemical parameter of the feedstock by introducing naphthenic acid, which specifically targets and neutralizes caustic compounds. This parameter change approach differs from conventional antifoulants that address general fouling mechanisms, providing specialized protection against caustic-induced fouling while maintaining effectiveness against other fouling types.
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
The additive effectively prevents caustic-induced fouling by neutralizing caustic compounds, maintaining operational severity, and reducing coke deposition, thereby extending furnace run length and maintaining product yield and quality.
Implementation Method 1
The additive comprising naphthenic acid, petroleum sulphonate, phosphate ester and gasoil provides an effective remedy for caustic induced furnace fouling by neutralizing and converting the caustic compound to naphthenate form
Data Source
AI summary
The furnace of a delayed coking unit which is utilized for heating residue feeds to high temperatures can suffer from decrease in run length and fouling caused by caustic carryover from the upstream desalter unit. An antifoulant additive for preventing caustic induced fouling of thermal cracker furnace tubes is disclosed. The described antifoulant additive acts by converting the inorganic caustic compound such as NaOH to naphthenate salt of the metal as well as by reducing the fouling tendency of the whole feedstock, thereby making it ineffective in causing coking reaction. The additive finds application in thermal residue upgradation furnaces such as delayed coking unit, visbreaker, etc.