Hydrocracking C6 Cut for Benzene Alkylation
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Solution Overview
Problem
The commercial production of high-purity alkylated aromatic hydrocarbons like ethylbenzene and cumene from mixed hydrocarbon feeds is hindered by the generation of undesired by-products in direct alkylation processes, making conventional aromatic extraction methods expensive and time-consuming.
Innovation Solution
A process involving hydrocracking of a C6 cut from a mixed hydrocarbon feedstream to produce benzene, followed by alkylation without the need for aromatic extraction, using distillation to separate the C6 cut and optimizing hydrocracking and alkylation conditions to enhance yield and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct alkylation of mixed C6 hydrocarbon feedstream is used, then the process is simpler, but many undesired by-products are produced which are difficult to separate
Solution Approach 1:
The process segments the mixed C6 hydrocarbon feedstream into different fractions through distillation, specifically isolating the C6 cut (boiling point range suitable for benzene production). This segmentation allows subsequent hydrocracking to selectively produce high-purity benzene, which then undergoes alkylation to yield high-purity alkylated aromatics without the separation difficulties of direct alkylation.
2Manufacturing precision
If aromatic extraction is used to purify benzene from mixed hydrocarbon feedstream, then high-purity benzene is obtained, but the process becomes expensive and time-consuming
Solution Approach 1:
The process performs preliminary action by conducting hydrocracking on the C6 cut before alkylation. This hydrocracking step pre-converts the C6 hydrocarbons into high-purity benzene, eliminating the need for subsequent aromatic extraction steps. The preliminary hydrocracking ensures that when alkylation occurs, the feed is already purified benzene, thus avoiding time-consuming extraction operations.
3Manufacturing precision
If aromatic extraction is used to remove benzene co-boilers, then sufficient benzene purity is achieved, but the process becomes expensive
Solution Approach 1:
The process changes the key parameter from post-separation purification (aromatic extraction) to pre-reaction conversion (hydrocracking). By adjusting the process parameters to include hydrocracking conditions (temperature, pressure, catalyst), the C6 cut is converted to benzene before alkylation. This parameter change eliminates expensive extraction solvents and equipment while achieving the required benzene purity through controlled chemical transformation.
4Quantity of substance
If benzene diluted with other hydrocarbons is subjected to alkylation, then the feed utilization is higher, but the alkylation reactor is larger and less efficient
Solution Approach 1:
The process performs preliminary purification through hydrocracking to produce concentrated high-purity benzene before alkylation. This preliminary action ensures that the alkylation reactor receives pure benzene feed rather than diluted mixtures, maximizing reactor efficiency and productivity. The concentrated benzene feed allows for more effective alkylation reactions and smaller, more efficient reactor design.
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 significantly increases the yield of high-purity aromatic compounds like benzene and cumene, allowing for benzene production with over 99 wt-% purity without extraction, and results in a more efficient and smaller alkylation reactor.
Implementation Method 1
subjecting C6 cut to hydrocracking to provide benzene
Implementation Method 2
subjecting benzene to alkylation to provide a product stream rich in alkylated aromatic hydrocarbons
Implementation Method 3
subjecting a mixed hydrocarbon feedstream to a separation to provide a C6 cut
Data Source
AI summary
The present invention relates to a process for producing alkylated aromatic hydrocarbons such as ethyl benzene or cumene from a mixed hydrocarbon feedstream comprising subjecting C6 cut separated from said mixed hydrocarbon feedstream to hydrocracking to provide benzene and subjecting said benzene to alkylation.