Dual-Riser FCC Unit for Co-Processing Vegetable Oil

Solution Overview

Problem

The challenge lies in economically justifying the processing of vegetable oil in Fluid Catalytic Cracking (FCC) units due to limited supply, which results in reduced yields and increased complexity when co-processed with petroleum-based feedstocks, necessitating a method to efficiently co-process these streams while maintaining acceptable diesel fuel production.

Innovation Solution

The method involves cracking two hydrocarbon streams at different process conditions using separate risers within an FCC unit, with one stream being vegetable oil processed at lower severity, and combining the catalysts and effluents to optimize diesel fuel production, allowing for a single reactor and fractionation zone to service both risers, thereby reducing capital and operating costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If vegetable oil is co-processed with vacuum gas oil in a single FCC unit, then renewable fuel production is achieved, but yields are reduced due to different processing severity requirements

Engineering Contradiction:

Improveability to process renewable feedstocksVSAvoiddiesel fuel yield

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The FCC unit is divided into two separate risers: a first riser for processing vacuum gas oil at higher severity conditions, and a second riser for processing vegetable oil at lower severity conditions. This segmentation allows each feedstock to be processed under its optimal conditions, maximizing diesel fuel yields from both streams while maintaining the ability to co-process renewable and petroleum-based feedstocks.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If a single FCC unit is used for both vegetable oil and petroleum feedstocks, then capital costs are reduced, but operational complexity increases due to different processing requirements

Engineering Contradiction:

Improvecapital costVSAvoidprocess operational complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The FCC unit is divided into two separate risers: a first riser for processing vacuum gas oil at higher severity conditions, and a second riser for processing vegetable oil at lower severity conditions. This segmentation allows each feedstock to be processed under its optimal conditions, maximizing diesel fuel yields from both streams while maintaining the ability to co-process renewable and petroleum-based feedstocks.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Both risers share common infrastructure including a single fractionation zone, catalyst handling system, and regenerator. This multi-functional design allows the system to process different feedstocks simultaneously while avoiding the need for completely separate processing units, thereby controlling capital costs while managing operational complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If vegetable oil is processed at lower severity to maximize diesel fuel production, then cetane number is improved, but overall productivity decreases when co-processed with vacuum gas oil

Engineering Contradiction:

Improvediesel fuel qualityVSAvoidoverall fuel production

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The FCC unit is divided into two separate risers: a first riser for processing vacuum gas oil at higher severity conditions, and a second riser for processing vegetable oil at lower severity conditions. This segmentation allows each feedstock to be processed under its optimal conditions, maximizing diesel fuel yields from both streams while maintaining the ability to co-process renewable and petroleum-based feedstocks.

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 enables efficient co-processing of vegetable oil and petroleum-based feedstocks, enhancing diesel fuel production with improved cetane numbers and reducing operational complexities, thus making it economically viable to utilize renewable resources while maintaining high yields.

Implementation Method 1

Hydrocarbons are cracked with a catalyst in a riser in an FCC unit

Methodology Applied

Scientific EffectCatalytic cracking: Catalysis

Implementation Method 2

the coke is burned in a regenerator to regenerate the catalyst

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS9527054B2Apparatuses and methods for cracking hydrocarbons

Publication Date: 2016.12.27 UOP LLC

AI summary

Methods and apparatuses are provided for cracking a hydrocarbon. The method includes contacting a first hydrocarbon stream with a first cracking catalyst at a first cracking temperature in a first riser to produce a first riser effluent and a first spent catalyst. A second hydrocarbon stream is contacted with a second cracking catalyst at a second cracking temperature in a second riser to produce a second riser effluent and a second spent catalyst, where the second cracking temperature is less than the first cracking temperature. The first riser effluent and the second riser effluent are combined to produce a mixed riser effluent, and the mixed riser effluent is fractionated in a fractionation zone to produce a light cycle oil. The first spent catalyst and the second spent catalyst are combined in a reactor to produce a mixed spent catalyst.