Hydrogen-Enriched Reverse Isomerization for Light Naphtha Cracking
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Solution Overview
Problem
Existing steam cracking processes for producing ethylene and propylene from light naphtha feedstocks are inefficient in converting iso-paraffins to normal paraffins, limiting the yield of high-value products.
Innovation Solution
A process involving a separation unit to generate iso-paraffin and normal paraffin streams, followed by mixing with hydrogen to form a hydrogen-enriched liquid feed, which is then processed in a reverse isomerization reactor with a solid catalyst to convert iso-paraffins to normal paraffins, and finally separating the effluent to recover the desired hydrocarbons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam cracking is used to convert hydrocarbons to ethylene and propylene, then high-value products are generated, but the conversion of iso-paraffins to normal paraffins is inefficient
Solution Approach 1:
The patent applies preliminary action by performing reverse isomerization conversion of iso-paraffins to normal paraffins before the steam cracking process. The feedstock is pre-treated in a reverse isomerization unit that converts difficult-to-crack iso-paraffins into easier-to-crack normal paraffins, thereby improving the overall efficiency of the steam cracking process and increasing ethylene and propylene yield.
Solution Approach 2:
The patent utilizes parameter changes by altering the chemical composition parameters of the feedstock through reverse isomerization. By changing the paraffin structure from branched (iso-) to straight-chain (normal) configuration, the feedstock properties are modified to enhance crackability and improve product distribution in the subsequent steam cracking process.
2Reliability
If normal paraffins are increased in the feedstock, then the quality of feedstock to steam cracking unit is improved, but the process complexity increases
Solution Approach 1:
The reverse isomerization unit performs preliminary conversion of iso-paraffins to normal paraffins before the feedstock enters the steam cracking unit. This pre-treatment step improves feedstock quality by increasing the concentration of normal paraffins, which are more readily cracked into desired products, while the modular design of the reverse isomerization unit helps manage process complexity.
3Productivity
If iso-paraffins are converted to normal paraffins, then the yield of high-value products is increased, but the process requires additional units and catalysts
Solution Approach 1:
The patent implements a reverse isomerization unit that performs preliminary conversion of iso-paraffins to normal paraffins before steam cracking. This unit uses specific catalysts (such as chlorinated alumina or zeolites) to facilitate the isomerization reaction, thereby improving the yield of high-value ethylene and propylene products while adding controlled complexity to the process.
Solution Approach 2:
The reverse isomerization process changes the chemical parameters of the feedstock by converting iso-paraffins to normal paraffins. This parameter change optimizes the feedstock composition for steam cracking, increasing the yield of high-value products. The process uses controlled catalysts and temperature conditions to achieve this transformation efficiently.
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
Increases the concentration of normal paraffins in the feedstock, enhancing the yield of ethylene and propylene and improving the profitability of steam cracking operations.
Implementation Method 1
contacting the hydrogen-enriched liquid feed stream with a solid reverse isomerization catalyst for reverse hydroisomerization in a substantially two-phase liquid-solid reverse isomerization fixed-bed reaction zone under conditions that minimize cracking reactions and that are effective to convert iso-paraffins to normal paraffins
Implementation Method 2
feeding a mixed feed stream comprising the light naphtha feedstock to a separation unit to generate an iso-paraffin stream and one or more normal paraffin streams
Implementation Method 3
mixing hydrogen gas and a hydrocarbon feed stream comprising the iso-paraffin stream to form a hydrogen-enriched liquid feed stream
Implementation Method 4
providing the isomerization effluent stream to a stabilization column to separate the isomerization effluent stream into a C1-C4 hydrocarbon stream and a stabilized isomerate stream
Data Source
AI summary
A process for reverse isomerization of a light naphtha feedstock containing branched C5-C7 paraffins. The process includes feeding a mixed feed stream including the light naphtha feedstock to a separation unit to generate an iso-paraffin stream and one or more normal paraffin streams. The process further includes mixing hydrogen gas and a hydrocarbon feed stream containing the iso-paraffin stream to form a hydrogen-enriched liquid feed stream which is provided to a reverse isomerization reactor. The hydrogen-enriched liquid feed stream is contacted with a solid reverse isomerization catalyst for reverse hydroisomerization in a substantially two-phase liquid-solid reverse isomerization fixed-bed reaction zone convert iso-paraffins to normal paraffins. The isomerization effluent stream is provided to a stabilization column to generate a stabilized isomerate stream which is combined with the light naphtha feedstock to generate the mixed feed stream. An associated system for performing the process is also provided.