Heavy Residue Upgrading via Segmented Hydrocracking
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Solution Overview
Problem
Conventional processes for upgrading refinery heavy residues to petrochemicals face inefficiencies due to high capital costs, hydrogen consumption, and difficulties in processing heavy crude oil cuts, leading to suboptimal yields of light olefins and aromatics, and result in significant production of low-value by-products.
Innovation Solution
A process involving the separation of hydrocarbon feedstocks into mono-aromatic and poly-aromatic streams, with subsequent processing in a gasoline hydrocracker and ring-opening reaction area, optimized to minimize coke formation and maximize BTX production, while integrating hydrogen management for cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heavy crude oil cuts are processed via conventional steam cracking, then light olefins and aromatics are produced, but substantial quantities of heavy by-products (C9+ aromatics and condensed aromatics) are generated reducing overall process efficiency
Solution Approach 1:
The process segments the heavy crude oil feedstock into different boiling point ranges through distillation, separating it into lighter cuts (naphtha, gas oils) and heavier residua. Each segment is then routed to appropriate processing units - lighter cuts to steam crackers and heavier cuts to hydrocrackers - optimizing product yields from each segment while minimizing heavy by-product formation.
Solution Approach 2:
The invention changes the processing parameters by introducing hydrocracking conditions (lower temperature, higher hydrogen pressure) for heavy residua instead of conventional steam cracking conditions. This parameter change converts the heavy aromatic species into lighter, more valuable products with significantly reduced formation of C9+ and condensed aromatics by-products.
2Productivity
If hydrocracking is used to upgrade heavy residues, then valuable light products are obtained, but capital costs increase significantly
Solution Approach 1:
The invention segments the crude oil processing into two parallel pathways: a steam cracking pathway for lighter cuts and a hydrocracking pathway for heavier residua. This segmentation allows each unit to be optimized for its specific feedstock, improving overall efficiency while distributing capital investment across two smaller, specialized units rather than one large, complex facility.
Solution Approach 2:
Instead of applying hydrocracking to all heavy crude oil feeds (excessive action), the invention applies it only to the heavier residua fraction that would otherwise produce excessive heavy by-products in steam crackers (partial action). This selective application optimizes the balance between product value and processing cost.
3Productivity
If high pressure and temperature are used for heavy stream hydrocracking, then conversion is achieved, but hydrogen consumption increases and light molecules such as methane are over-produced
Solution Approach 1:
The invention optimizes hydrocracking parameters by operating at lower temperatures (300-450°C) and moderate pressures compared to conventional heavy stream hydrocracking. This parameter change, combined with specific catalyst selection, achieves adequate conversion of heavy aromatics while significantly reducing hydrogen consumption and minimizing over-cracking to methane.
Solution Approach 2:
The invention applies different processing conditions to different feedstock segments: lighter cuts receive steam cracking treatment while heavier residua receive hydrocracking. This local quality approach ensures each segment receives the most appropriate treatment, avoiding the excessive hydrogen consumption and methane production that would result from uniform high-severity hydrocracking of all feeds.
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 enhances the yield of light olefins and BTX, reduces hydrogen consumption, and lowers operational costs by optimizing the hydrocracking process to handle heavy residues more efficiently, thereby improving carbon efficiency and hydrogen integration.
Implementation Method 1
separating a hydrocarbon feedstock in a distillation unit into a overhead stream and a bottom stream
Implementation Method 2
hydro-cracking (whereby the hydro-cracker feed is exposed to a suitable catalyst under conditions which result in some fraction of the feed molecules being broken into shorter hydrocarbon molecules with the simultaneous addition of hydrogen)
Implementation Method 3
steam cracking in which the hydrocarbon feed stream is evaporated and diluted with steam and then exposed to a very high temperature (800° C. to 860° C.) in short residence time
Data Source
AI summary
The present invention relates to a process for upgrading refinery heavy residues to petrochemicals, comprising the following steps of:(a) separating a hydrocarbon feedstock in a distillation unit into a to overhead stream and a bottom stream(b) feeding said bottom stream to a hydrocracking reaction area(c) separating reaction products, which are generated from said reaction area of step (b) into a stream rich in mono-aromatics and in a stream rich in poly-aromatics(d) feeding said stream rich in mono-aromatics to a gasoline hydrocracker (GHC) unit,(e) feeding said stream rich in poly-aromatics to a ring opening reaction area.