Hydrogen Separation Train for Olefin Effluent Purity and Recovery
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Solution Overview
Problem
Existing processes for separating hydrogen from olefin hydrocarbon vapor streams in dehydrogenation units are inefficient and lack comprehensive steps to effectively isolate and purify hydrogen, leading to suboptimal results.
Innovation Solution
A multi-step process involving cooling, separation, isentropic expansion, compression, and rectification in a system with heat exchangers and expanders to isolate hydrogen from olefin and heavy paraffinic components, followed by further purification in a rectifier, allowing for efficient hydrogen recovery and purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing separation processes are used, then hydrogen separation is achieved, but the recovery efficiency and purity are insufficient
Solution Approach 1:
The separation process is divided into multiple stages: initial cooling and separation in the first separator, further cooling and separation in the second separator, and final purification in the rectifier. Each stage targets specific components at different temperature and pressure levels, achieving both high purity and high recovery efficiency through progressive refinement
Solution Approach 2:
The process utilizes systematic changes in temperature and pressure parameters across different units. The effluent is cooled to specific temperatures in heat exchangers, pressurized in compressors, and expanded in expanders to create conditions optimal for separating hydrogen from olefin and paraffinic components at each stage
2Manufacturing precision
If comprehensive multi-step separation is implemented, then hydrogen purity is improved, but process complexity increases
Solution Approach 1:
The heat exchanger serves multiple functions: cooling the effluent stream, condensing olefin and paraffinic components, and providing heat recovery. The compressors and expanders both control pressure and contribute to temperature management. This multi-functionality reduces the need for separate dedicated equipment for each function, managing complexity while achieving comprehensive separation
Solution Approach 2:
The process combines cooling, compression, expansion, and separation operations into an integrated flow where equipment serves multiple purposes. The first and second separators work in series with the rectifier, creating a unified separation train that achieves high purity without requiring entirely separate systems for each separation function
3Loss of energy
If isentropic expansion and compression are used, then thermodynamic efficiency is improved, but off-design flow issues may arise
Solution Approach 1:
The compressors and expanders are operated to maintain isentropic conditions during normal design flow, maximizing thermodynamic efficiency. The system dynamically adjusts operating parameters to handle off-design conditions while preserving the efficiency benefits during optimal operation
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 process achieves high hydrogen recovery and purity, improving the efficiency and stability of hydrogen separation from olefin hydrocarbon vapor streams, enhancing thermodynamic efficiency and reducing off-design flow issues.
Implementation Method 1
cooling a compressed effluent vapor stream in a heat exchanger
Implementation Method 2
separating hydrogen from olefin and heavy paraffinic components in the cooled compressed effluent vapor stream
Implementation Method 3
isentropically expanding, in a high-pressure expander, the second vapor stream, wherein the pressure and temperature of the second vapor stream are lowered
Implementation Method 4
compressing, in a high-pressure compressor, the second vapor stream
Implementation Method 5
compressing, in a high-pressure compressor, the second vapor stream
Implementation Method 6
separating hydrogen from olefin and heavy paraffinic components in the cooled compressed effluent vapor stream in a first separator to provide a first vapor stream and a first liquid stream
Implementation Method 7
combining the hydrogen-rich gas and the second liquid stream in the rectifier, further purifying the hydrogen-rich gas
Data Source
AI summary
One or more specific embodiments disclosed herein includes a method for separating hydrogen from an olefin hydrocarbon rich compressed effluent vapor stream, employing a single heat exchanger, multiple gas-liquid separators, multiple expander/compressor sets, and a rectifier attached to a liquid product drum.