FCC Cycle Oil Recovery via Vacuum Separation and Hydrocracking

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Solution Overview

Problem

The FCC process generates clarified slurry oil (CSO) that is less valuable due to its heavy composition and high aromaticity, which degrades diesel quality and is not efficiently recovered, leading to operational challenges and product losses.

Innovation Solution

Integrating an FCC unit with a hydrocracking unit to separate and recover cycle oil from CSO, using a vacuum separator to refine this material, which is then fed back into the hydrocracking unit to produce higher-value diesel and petrochemical products.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LCO is withdrawn from the main fractionation column to prevent coking, then maintenance issues are reduced, but LCO is lost and cannot be recovered

Engineering Contradiction:

Improvemaintenance reliabilityVSAvoidLCO loss

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The invention extracts LCO from the CSO stream using a side draw in the main fractionation column. This allows LCO to be separated and recovered while the remaining CSO can be processed further, resolving the contradiction between preventing coking (by removing LCO) and recovering LCO (to avoid loss).

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of discarding LCO when withdrawing CSO to prevent coking, the invention recovers LCO through the side draw mechanism. This transforms the harmful waste stream into a recoverable valuable product, simultaneously addressing maintenance reliability and substance loss.

Inventive Principle:

Principle #34Discarding and recovering

2Temperature

If CSO is withdrawn with extra LCO to lower main fractionation column temperature, then coking is reduced, but valuable LCO is lost in the CSO stream

Engineering Contradiction:

Improvemain fractionation column temperatureVSAvoidLCO loss

Core Design Contradiction:

TemperatureVSLoss of substance

Solution Approach 1:

The side draw mechanism extracts LCO from the CSO stream at a specific point in the main fractionation column. This allows temperature control (by adjusting withdrawal rates) while simultaneously recovering LCO, preventing both coking and substance loss.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the operational parameters by introducing a side draw at a specific location and operating conditions. This enables independent control of temperature and LCO recovery, resolving the contradiction between lowering temperature (to reduce coking) and preventing LCO loss.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If CSO is processed as fuel without recovery, then operational simplicity is maintained, but valuable hydrocarbons are lost

Engineering Contradiction:

Improveoperational simplicityVSAvoidhydrocarbon loss

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The side draw mechanism provides a simple yet effective way to extract LCO from CSO without requiring complex additional processing units. This maintains operational simplicity while preventing hydrocarbon loss through recovery and reuse.

Inventive Principle:

Principle #2Taking out (Extraction)

4Quantity of substance

If LCO is sent to the diesel pool, then diesel volume is increased, but diesel quality is degraded due to high aromaticity and low cetane value

Engineering Contradiction:

Improvediesel volumeVSAvoiddiesel quality degradation

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

By extracting LCO from the CSO stream via side draw, the invention prevents LCO from degrading diesel quality while still allowing LCO to be recovered and used as a separate product or feedstock, thus avoiding both quality degradation and substance loss.

Inventive Principle:

Principle #2Taking out (Extraction)

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 process enables the recovery and upgrading of LCO and HCO from CSO, enhancing diesel quality and increasing the yield of lighter products like gasoline, kerosene, and aromatics, thereby improving the overall efficiency and value of the refining process.

Implementation Method 1

separating the slurry oil stream into a cycle oil stream and a heavy stream under vacuum pressure

Methodology Applied

Scientific EffectVacuum distillation: Vacuum Distillation

Implementation Method 2

Hydrocracking is a hydroprocessing process in which hydrocarbons crack at the carbon-carbon bonds in the presence of hydrogen and hydrocracking catalyst

Methodology Applied

Scientific EffectHydrocracking:

Implementation Method 3

contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream

Methodology Applied

Scientific EffectCatalytic cracking: Catalysis

Data Source

PatentUS9394496B2Process for fluid catalytic cracking and hydrocracking hydrocarbons

Publication Date: 2016.07.19 UOP LLC

AI summary

A process and apparatus for recovering cycle oil from FCC CSO is described. By feeding the additional cycle oil to a hydrocracking unit additional diesel, naphtha and petrochemical feedstock may be obtained. The additional cycle oil is obtained by vacuum separation of the CSO. The described process and apparatus can provide additional recovery for a refiner.