Selective Ethylene Oligomerization for Flexible Benzene Production
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Solution Overview
Problem
Conventional methods of benzene production from crude oil are becoming increasingly expensive due to rising demand, and alternative methods using natural gas as a starting material are desirable to lower costs.
Innovation Solution
A method involving selective-higher-olefin oligomerization of ethylene using specific catalysts to produce C6 and C8 hydrocarbons, followed by hydrotreating and aromatization processes to yield benzene, with integrated systems for ethylene conversion into benzene and other valuable hydrocarbons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional crude oil-based methods are used for benzene production, then benzene can be produced through established refining processes, but production costs increase due to rising crude oil demand and prices
Solution Approach 1:
The invention changes the fundamental parameter of feedstock source from crude oil to natural gas (specifically ethylene). This parameter change enables benzene production through a different chemical pathway (oligomerization of ethylene to C6-C8 hydrocarbons followed by aromatization), thereby reducing dependence on crude oil and mitigating cost increases associated with rising crude oil demand
Solution Approach 2:
The invention introduces C6-C8 hydrocarbon intermediates (specifically 1-hexene and 1-octene) as mediators in the transformation from ethylene to benzene. These intermediates are produced through selective oligomerization and then converted to benzene via aromatization, providing a multi-step pathway that enables cost-effective benzene production from natural gas feedstock
2Manufacturing precision
If selective-higher-olefin oligomerization is used to produce C6 and C8 hydrocarbons from ethylene, then high purity 1-hexene and 1-octene can be obtained, but additional processing steps (hydrotreating and aromatization) are required
Solution Approach 1:
The invention performs preliminary selective oligomerization to produce high-purity C6 and C8 hydrocarbons (1-hexene and 1-octene) with specific purity ranges (60-99.9 wt.% for 1-hexene and 95-99.3 wt.% for 1-octene) before subsequent hydrotreating and aromatization steps. This preliminary purification enables the catalyst to function effectively in later stages and ensures high benzene yield
Solution Approach 2:
The invention segments the overall benzene production process into distinct functional stages: (1) selective oligomerization of ethylene to C6-C8 hydrocarbons, (2) hydrotreating to saturate olefins, and (3) aromatization to produce benzene. This segmentation allows each stage to be optimized independently, with the first stage focusing on producing high-purity intermediates that enable effective downstream processing
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
The method achieves high purity levels of 1-hexene and 1-octene and produces benzene efficiently, along with other valuable hydrocarbons like toluene and xylene, while reducing production costs by utilizing natural gas as a starting material.
Implementation Method 1
contacting, in an oligomerization process, ethylene with a selective-higher-olefin catalyst to yield an oligomerization reactor effluent comprising 1) C6 hydrocarbons which include 1-hexene and 2) C8 hydrocarbons which include 1-octene
Implementation Method 2
contacting, in a hydrotreating process, 1-hexene, 1-octene, or both 1-hexene and 1-octene recovered from the oligomerization reactor effluent with a hydrogenation catalyst to yield an aromatization feed comprising hexane, octane, or both
Implementation Method 3
contacting, in an aromatization process, the aromatization feed with an aromatization catalyst to yield reformate effluent comprising benzene
Data Source
AI summary
The present disclosure relates to the integration of systems and methods associated with steam cracking, oligomerization reactions, hydrogenation reactions, and aromatization reactions for the production of benzene via the hydrogenation of oligomers produced from ethylene. In some aspects, the disclosed systems and methods utilize one or more of an oligomerization process, a hydrotreating process, and an aromatization process for producing a benzene comprising effluent. In further aspects, the systems and methods disclosed herein utilize one or more selective oligomerization catalyst systems.