Benzene Reduction in Reformate via Combined Stabilizer and Naphtha Splitter
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Solution Overview
Problem
Current catalytic reforming processes face challenges in efficiently removing and concentrating benzene from reformate streams to meet stringent gasoline blending requirements, as benzene is a product that needs to be limited in gasoline due to environmental regulations.
Innovation Solution
A process involving a combined stabilizer-naphtha splitter system that separates a heart cut stream to remove benzene, followed by concentration in a side stripper bottoms stream, and subsequent benzene saturation using a hydrogenation reactor, allowing for the recycling of valuable hydrocarbons and reduction of benzene in the reformate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If catalytic reforming is used to increase octane rating, then higher octane gasoline is produced, but benzene concentration increases which violates environmental regulations
Solution Approach 1:
The reformate stream is divided into multiple fractions through fractional distillation in the stabilizer-naphtha splitter, separating benzene-containing heart cut from other components. This segmentation allows selective removal of benzene while retaining valuable hydrocarbons for blending
Solution Approach 2:
Benzene is extracted from the reformate stream by isolating the heart cut fraction through distillation, then concentrating it in the side stripper. The extracted benzene is subsequently saturated in the hydrogenation reactor, effectively removing it from the gasoline pool
2Object-affected harmful factors
If benzene is removed from reformate through conventional separation, then benzene concentration is reduced, but valuable hydrocarbons are lost
Solution Approach 1:
The distillation column separates reformate into distinct fractions (overhead, side cut, heart cut, bottoms), allowing selective withdrawal of the benzene-rich heart cut while returning other valuable hydrocarbon fractions to the blending pool
Solution Approach 2:
Only the specific heart cut fraction containing benzene is discarded for saturation, while other fractions are recovered and returned to the gasoline blending pool, maximizing hydrocarbon utilization
3Object-affected harmful factors
If multiple separation units are used to remove benzene, then benzene concentration is reduced, but process complexity increases
Solution Approach 1:
The stabilizer and naphtha splitter are combined into a single distillation column that performs both stabilization (removing light ends) and naphtha splitting (separating C5-C6 from C7+), simultaneously producing the benzene-rich heart cut fraction
Solution Approach 2:
The combined column serves multiple functions: stabilizing reformate, splitting naphtha fractions, and concentrating benzene in the heart cut, replacing what would traditionally require multiple separate units
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
Effectively reduces benzene concentration in the reformate, enabling the recovery and saturation of benzene, thus meeting environmental standards and optimizing gasoline blending components.
Implementation Method 1
separating the reformate in a combined stabilizer naphtha splitter to remove benzene in a heart cut stream
Implementation Method 2
concentrating the benzene from the heart cut stream in a side stripper bottoms stream
Implementation Method 3
saturating the benzene in the side stripper bottoms stream
Implementation Method 4
saturating the benzene in the side stripper bottoms stream
Data Source
AI summary
A process and system for separating and saturating benzene from a reforming reactor effluent begins with introducing the reforming reactor effluent to a combined stabilizer and naphtha splitter. An overhead stream comprising light ends, a sidecut stream comprising C4− C5 compounds, a bottoms stream comprising C7+ compounds and a heart cut stream comprising C4, C5, C6 compounds including benzene are all removed from the combined stabilizer and naphtha splitter. The heart cut stream is introduced to a side stripper to produce a side stripper overhead stream reduced in benzene and a side stripper bottoms stream enriched in benzene. At least a portion of the side stripper bottoms stream enriched in benzene is introduced into a hydrogenation zone to saturate benzene and generate a hydrogenation zone effluent reduced in benzene. The side stripper overhead stream may be recycled to the combined stabilizer and naphtha splitter.