BTX Absorption of LPG in Hydrocracking Separation
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Solution Overview
Problem
Current processes for producing BTX and LPG are energy-intensive due to the requirement for cryogenic cooling to separate methane and C2 hydrocarbons, which increases operational costs and energy consumption.
Innovation Solution
A hydrocracking process that contacts a feed stream of C5-C12 hydrocarbons with hydrogen using a hydrocracking catalyst, followed by separation steps where BTX is used to absorb LPG from gas streams, eliminating the need for cryogenic cooling and reducing energy consumption by utilizing the high affinity between BTX and LPG for separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cryogenic cooling is used to separate methane and C2 hydrocarbons, then separation purity is improved, but energy consumption increases
Solution Approach 1:
The patent extracts and removes the energy-intensive cryogenic cooling step from the separation process. Instead of using cryogenic temperatures to separate methane and C2 hydrocarbons, the process uses atmospheric or near-atmospheric pressure distillation with selective condensation, thereby eliminating the harmful energy consumption while maintaining separation purity.
Solution Approach 2:
The patent changes the operating parameters from cryogenic temperatures to atmospheric or near-atmospheric conditions. By adjusting the condensation temperature and pressure parameters, the process achieves effective separation without requiring extreme cooling, thus resolving the contradiction between separation purity and energy consumption.
2Manufacturing precision
If multiple distillation steps are applied to separate BTX from hydrocracking products, then product purity is improved, but process complexity increases
Solution Approach 1:
The patent removes unnecessary distillation steps from the conventional multi-step separation process. By using selective condensation at controlled temperatures, the process directly separates BTX, LPG, and other components in a single or reduced number of stages, thereby maintaining product purity while significantly reducing process complexity.
Solution Approach 2:
The patent introduces a selective condensation mechanism as an intermediary separation method between hydrocracking and final product collection. This intermediary step uses temperature-controlled condensation to selectively separate components based on their boiling points, replacing multiple complex distillation steps with a simpler, more efficient process.
3Ease of operation
If conventional separation methods are used without solvent recycling, then process simplicity is maintained, but substance loss increases
Solution Approach 1:
The patent implements a feedback mechanism where unreacted hydrogen and light hydrocarbons from the product stream are recycled back to the hydrocracking reactor. This feedback loop ensures that valuable substances are not lost but continuously reused, improving atomic economy while maintaining process simplicity through integrated recycling.
Solution Approach 2:
The patent recovers and reuses substances that would otherwise be discarded, specifically unreacted hydrogen and light hydrocarbons. By integrating a recycling stream that feeds these components back into the hydrocracking process, the system minimizes substance loss while maintaining operational simplicity through a closed-loop approach.
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 reduces energy intensity by allowing separation of LPG and methane/hydrogen without cryogenic cooling, achieving high purity BTX and LPG production with lower energy expenditure and no additional solvent requirements.
Implementation Method 1
contacting a feed stream comprising C5-C12 hydrocarbons in the presence of hydrogen with a hydrocracking catalyst in a hydrocracking reactor to produce a hydrocracking product stream comprising hydrogen, methane, LPG and BTX
Implementation Method 2
step (c) involves adding a part of the third liquid stream to the first gas stream to absorb the LPG in the first gas stream to obtain the second liquid stream
Data Source
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AI summary
The invention is directed to a process for producing BTX and LPG, comprising: a) contacting a feed stream comprising C5-C12 hydrocarbons in the presence of hydrogen with a hydrocracking catalyst in a hydrocracking reactor to produce a hydrocracking product stream comprising hydrogen, methane, LPG and BTX, b) separating the hydrocracking product stream into a first gas stream and a first liquid stream, c) separating the first gas stream to obtain a second gas stream comprising hydrogen and methane and a second liquid stream comprising LPG and BTX, wherein the separation is performed such that the second liquid stream is substantially free of hydrogen and methane, d) separating the second liquid stream into a third gas stream comprising LPG and a third liquid stream comprising BTX, wherein step (c) involves adding a part of the third liquid stream to the first gas stream to absorb the LPG in the first gas stream to obtain the second liquid stream or adding a part of the third liquid stream to a gas stream separated from the first gas stream to absorb the LPG in said gas stream separated from the first gas stream to obtain the second liquid stream.