Fluidized Catalytic Cracking Disulfide Oil to BTX
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Solution Overview
Problem
The processing of disulfide oil (DSO) compounds and their derivatives poses challenges in their disposal and utilization due to their low value and environmental concerns, as they contain sulfur, which is problematic for refineries, and there is a need for an efficient method to convert them into valuable products like BTX (benzene, toluene, and xylene) to enhance their value and facilitate environmentally acceptable disposal.
Innovation Solution
Introducing DSO compounds into a fluidized catalytic cracking (FCC) unit, followed by selective naphtha hydrogenation and hydrotreating, and then processing the resulting hydrotreated naphtha stream in an aromatics unit to separate and produce BTX and other aromatic products, thereby converting low-value DSO into high-value BTX and other aromatics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If disulfide oil is directly disposed of or used as fuel blend stock, then disposal is simplified, but environmental compliance is violated due to high sulfur content
Solution Approach 1:
The patent converts the harmful sulfur-containing disulfide oil into valuable BTX aromatic products through fluidized catalytic cracking. The sulfur is removed during the cracking process, transforming a harmful waste stream into a beneficial chemical product stream that complies with environmental standards while generating revenue.
Solution Approach 2:
The patent fundamentally changes the chemical parameters of disulfide oil by subjecting it to high-temperature catalytic cracking conditions. This transforms the molecular structure from sulfur-containing compounds into sulfur-free aromatic hydrocarbons, altering both the composition and value of the material.
2Object-affected harmful factors
If disulfide oil is converted to BTX through fluidized catalytic cracking, then environmental compliance is achieved, but the process complexity increases
Solution Approach 1:
The patent integrates the disulfide oil cracking unit into the existing FCC refinery complex, allowing the same catalytic cracking infrastructure to handle both conventional vacuum gas oil and disulfide oil feedstocks. This multi-functionality approach converts a potentially complex standalone process into an integrated unit that leverages existing equipment and expertise.
3Productivity
If conventional FCC processes are used for disulfide oil cracking, then conversion to BTX is achieved, but excessive coke formation occurs reducing liquid hydrocarbon yield
Solution Approach 1:
The patent modifies the catalyst properties to create local quality differences in the cracking process. By using catalysts with specific acid distributions and metal compositions, the process achieves selective cracking of disulfide oil to BTX while minimizing excessive coke formation and maximizing liquid hydrocarbon yields in the desired product range.
4Speed
If high reaction temperatures are used to accelerate conversion, then cracking rate increases, but coke formation increases and liquid product yield decreases
Solution Approach 1:
The patent optimizes the reaction temperature parameter to a specific range (450-650°C) that balances cracking rate with product distribution. This optimized temperature parameter allows sufficient conversion of disulfide oil to BTX while preventing excessive coke formation that would occur at higher temperatures, thereby maintaining liquid hydrocarbon yield.
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 integrated process effectively converts DSO into valuable BTX and aromatic products, enhancing their value and enabling environmentally acceptable disposal, while reducing sulfur and nitrogen compounds to levels suitable for aromatics extraction, thus addressing the disposal and utilization challenges of DSO.
Implementation Method 1
Fluidized catalytic cracking (FCC) is a ubiquitous and very important process in hydrocarbon refinery operations. The FCC process catalytically converts, or cracks, hydrocarbon feedstocks
Implementation Method 2
Under these reaction temperatures, two competing cracking reactions occur, thermal cracking and catalytic cracking
Implementation Method 3
introducing the FCC liquid hydrocarbon products stream with an effective amount of hydrogen into a selective naphtha hydrogenation and hydrotreating zone to remove all or a substantial portion of diolefins, olefins, sulfur and nitrogen compounds
Implementation Method 4
processing the resulting hydrotreated naphtha stream in an aromatics unit to separate and produce BTX and other aromatic products
Data Source
AI summary
Relatively low value disulfide oil (DSO) compounds produced as by-products of the mercaptan oxidation (MEROX) processing of refinery hydrocarbon streams, and oxidized disulfide oils (ODSO), are economically converted to value-added BTX by introducing the DSO and/or ODSO compounds as the feed to a fluidized catalytic cracking (FCC) unit and recovering the liquid products. The liquid FCC products are introduced as the feedstream to a selective naphtha hydrogenation and hydrotreating process for desulfurization and are then further separated in an aromatics extraction process for the recovery of BTX.