HPNA Stripping via Split Shell Fractionation Vapor Reuse

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing catalytic hydroprocessing methods, particularly hydrocracking, face challenges with the accumulation of heavy polynuclear aromatics (HPNA) compounds, which lead to catalyst deactivation and require substantial stripping steam, increasing the size and energy consumption of fractionation columns.

Innovation Solution

A process that utilizes the vapor from the HPNA stripping section as the stripping medium for the bottom stripping zone of the product fractionation column, reducing the total stripping steam requirement and improving separation efficiency by optimizing the liquid-to-vapor ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If substantial stripping steam is used to strip lighter materials from HPNA's in the fractionation column, then the separation efficiency is improved, but the column size and energy consumption increase significantly

Engineering Contradiction:

Improveseparation efficiencyVSAvoidcolumn size

Core Design Contradiction:

Manufacturing precisionVSVolume of stationary object

Solution Approach 1:

The patent combines the stripping function for both compartments into a single integrated system. The stripping vapor generated in the second compartment (for HPNA stream) is reused to provide stripping action in the first compartment (for main feed), merging two separate stripping operations into one coordinated process that reduces overall steam requirements and column size.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The stripping vapor stream serves multiple functions: it strips lighter materials from the HPNA-containing stream in the second compartment, and then the same vapor is used to strip lighter materials from the main feed in the first compartment. This multi-functional use of the stripping vapor reduces the total steam requirement and allows for a more compact column design.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If substantial stripping steam is used to strip lighter materials from HPNA's in the fractionation column, then the separation efficiency is improved, but the energy consumption increases significantly

Engineering Contradiction:

Improveseparation efficiencyVSAvoidenergy consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by stationary object

Solution Approach 1:

The patent converts what would be waste vapor (enriched stripping vapor from the second compartment) into a useful resource by routing it to the first compartment to provide stripping action. This transforms a potential waste stream into a beneficial contribution to the overall separation process, reducing the need for additional steam and associated energy consumption.

Inventive Principle:

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

Solution Approach 2:

Instead of discarding the enriched stripping vapor from the second compartment, the patent recovers and utilizes it in the first compartment. This recovery approach eliminates the need to generate additional stripping steam for the first compartment, thereby reducing energy consumption while maintaining separation efficiency.

Inventive Principle:

Principle #34Discarding and recovering

3Manufacturing precision

If a split shell fractionator is used to concentrate HPNA's, then the HPNA removal efficiency is improved, but the device complexity increases

Engineering Contradiction:

ImproveHPNA removal efficiencyVSAvoidfractionation column configuration

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The fractionation column is divided into two distinct compartments: a first compartment for receiving and stripping the main hydrocarbon feed, and a second compartment for receiving and stripping the HPNA-containing stream. This segmentation allows each compartment to be optimized for its specific function while maintaining an integrated overall system.

Inventive Principle:

Principle #1Segmentation

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 significantly reduces the total stripping steam requirement, minimizes column diameter and overhead condenser system size, and enhances separation efficiency, achieving better product quality and energy efficiency.

Implementation Method 1

A stripping vapor is fed to the second compartment to strip lighter hydrocarbons from the hydroprocessed stream and provide a stripped hydroprocessed stream

Methodology Applied

Scientific EffectStripping: Distillation

Implementation Method 2

the enriched stripping vapor is passed to the first compartment in the fractionation column

Methodology Applied

Scientific EffectVapor flow: Convection

Data Source

PatentUS8574425B2Process for removing heavy polynuclear aromatic compounds from a hydroprocessed stream

Publication Date: 2013.11.05 UOP LLC

AI summary

The present invention is an improved process for stripping HPNA's from hydroprocessed streams in a fractionation column having a split shell configuration. Only one vapor stripping feed is required to the split shell of the fractionation column. The resulting reduction in steam requirement provides a superior fractionation in the column.