Steam Cracker Sample Conditioning for Cleaner C3− Analysis
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Solution Overview
Problem
Current sample conditioning systems for steam cracker effluents suffer from fouling, insufficient cooling, and liquid carryover, leading to unreliable analysis of C3− components in gas chromatographs.
Innovation Solution
Implementing a flow restricting line with a smaller cross-sectional area to slow down the sample flow, followed by a transport line, which reduces fouling and enhances cooling, resulting in a cleaner and drier sample for analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sample flow rate is increased to improve analysis speed, then productivity is improved, but fouling increases and reliability deteriorates
Solution Approach 1:
The patent intentionally slows down the sample flow through a restricted flow path, allowing the sample to 'rush through' the condensation zone with extended residence time. This counterintuitive approach of reducing flow speed to improve overall system reliability resolves the contradiction by preventing fouling while maintaining adequate analysis throughput.
Solution Approach 2:
The patent changes the flow rate parameter from high to low within the sample conditioning system. By reducing the sample flow rate through the condensation zone, the system achieves better condensation efficiency and reduced fouling, thereby improving reliability without significantly compromising overall productivity.
2Reliability
If cooling time is increased to improve condensation efficiency, then reliability is improved, but loss of time increases
Solution Approach 1:
The patent utilizes phase transition of steam to liquid water through controlled condensation. By designing a flow restricting line that maintains the sample in a specific temperature and pressure range, the system achieves efficient steam condensation without excessive processing time, resolving the contradiction between condensation efficiency and time loss.
Solution Approach 2:
The patent performs preliminary cooling and condensation of the sample stream before it reaches the analytical instrument. The flow restricting line is positioned upstream to pre-condition the sample, removing the bulk of the steam and heavy components before analysis, thereby achieving reliable condensation without significant time loss in the overall process.
3Reliability
If the sample flow velocity is increased to reduce contact time with foulants, then reliability is improved, but cooling efficiency deteriorates
Solution Approach 1:
The patent introduces a spatial dimension by creating a restricted flow path with specific geometry. The flow restricting line provides a longer, more tortuous path that increases surface area contact for cooling while maintaining linear flow progress. This dimensional approach allows simultaneous achievement of fouling resistance and cooling efficiency.
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 system significantly improves the reliability of C3− sample analysis by reducing fouling and doubling the contact time for cooling, thereby increasing the reliability of the sample conditioning system to over 90%.
Implementation Method 1
Heat can be indirectly exchanged from the sample to a heat transfer medium to produce a first gas phase product that can include C3− compounds and a first liquid phase product that can include C4+ compounds
Implementation Method 2
The C3− components that need to be analyzed are currently separated in sample conditioning system (often called a transfer line sampler or TLS) that is configured to filter particulates and condense steam and C4+ heavy components
Data Source
AI summary
Processes and systems for analyzing a composition of a C3− component separated from a steam cracker effluent. The process can include steam cracking a hydrocarbon feed to produce a steam cracker effluent. The effluent can be cooled to produce a cooled effluent and a sample can be separated therefrom. Heat can be indirectly exchanged from the sample to a heat transfer medium to produce a gas phase product that can include C3− compounds and a first liquid phase product that can include C4+ compounds. The gas phase product can flow through a flow restricting line and into a transport line. The flow restricting line can have an inner cross-sectional area that is <50% of an inner cross-sectional area of the transport line. The gas phase product can flow through the transport line and into an analyzer. An at least partial composition of the gas phase product can be determined.