Dual Catalyst Propylene Production from Butene

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Solution Overview

Problem

The demand for propylene has exceeded its supply, as current production processes such as steam cracking and fluid catalytic cracking cannot adequately respond to the rapid increase in demand, and alternative processes like propane dehydrogenation and metathesis reactions are inefficient.

Innovation Solution

A multiple-stage catalyst system comprising a metathesis reaction zone with a mesoporous silica-alumina catalyst support impregnated with metal oxide and a cracking reaction zone with a MFI structured silica-containing catalyst is used to convert butene into propylene, enhancing yield and selectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If steam cracking or fluid catalytic cracking is used for propylene production, then ethylene or gasoline production is improved, but propylene supply cannot meet the rapid increase in demand

Engineering Contradiction:

Improvepropylene production capacityVSAvoidresponse to propylene demand increase

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The process is divided into two distinct reaction zones: a metathesis reaction zone for converting butene to propylene and ethylene, and a cracking reaction zone for converting remaining butene and heavier hydrocarbons to propylene. This segmentation allows each zone to be optimized for its specific function, thereby significantly increasing overall propylene production capacity and responsiveness to demand.

Inventive Principle:

Principle #1Segmentation

2Productivity

If alternative processes like propane dehydrogenation or metathesis reactions are used, then propylene production is increased, but efficiency is reduced

Engineering Contradiction:

Improvepropylene productionVSAvoidprocess efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent combines metathesis reaction and cracking reaction into a single integrated process. The metathesis reaction zone converts butene to propylene and ethylene, while the cracking reaction zone simultaneously converts remaining butene and heavier hydrocarbons to propylene. This merging of functions in a unified two-zone reactor system improves overall process efficiency by eliminating the need for separate processes and reducing energy losses associated with multiple unit operations.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If a single catalyst system is used for butene conversion, then device complexity is reduced, but yield and selectivity of propylene are insufficient

Engineering Contradiction:

Improvepropylene yield and selectivityVSAvoidcatalyst system structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The catalyst system is segmented into two distinct zones with different catalyst compositions optimized for their specific functions. The metathesis reaction zone uses a catalyst formulated for high metathesis activity, while the cracking reaction zone uses a catalyst optimized for cracking reactions. This segmentation of the catalyst system enables high propylene yield and selectivity by ensuring each catalyst operates under optimal conditions for its intended reaction, without requiring overly complex multi-catalyst formulations in a single zone.

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 increases the yield and selectivity of propylene production, allowing for efficient conversion of butene to propylene while reducing unwanted side reactions and energy costs.

Implementation Method 1

at least partially metathesizing butene in a metathesizing reaction zone that may comprise a metathesis catalyst to form a metathesis reaction product

Methodology Applied

Scientific EffectMetathesis reaction: Chemical Bonding

Implementation Method 2

at least partially cracking the metathesis reaction product in a cracking reaction zone that may comprise a cracking catalyst to form a cracking reaction product

Methodology Applied

Scientific EffectCatalytic cracking: Catalysis

Data Source

PatentUS10919822B2Dual catalyst processes and systems for propylene production

Publication Date: 2021.02.16 SAUDI ARABIAN OIL CO

AI summary

Processes and multiple-stage catalyst systems are disclosed for producing propylene from butene by at least partially metathesizing butene in a metathesizing reaction zone having a metathesis catalyst to form a metathesis reaction product and at least partially cracking the metathesis reaction product in a cracking reaction zone having a cracking catalyst to form a cracking reaction product that includes propylene. The metathesis catalyst may be a mesoporous silica-alumina catalyst support impregnated with metal oxide having a mesoporous silica-alumina catalyst support comprising from 5 weight percent to 50 weight percent alumina. The cracking catalyst may be a MFI structured silica-containing catalyst. The cracking reaction zone may be downstream of the metathesis reaction zone.