Ethane separation with overhead cryogenic heat exchanger
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cryogenic separation systems for propylene production are inefficient and costly due to the need for multiple deethanizer columns and refrigeration packages, which increase capital and operational expenses.
Innovation Solution
Integration of a deethanizer column with a cryogenic heat exchanger using a single refrigerant system for condensing overhead streams, eliminating the need for steam reboiling and reducing fractionation costs by utilizing two cryogenic heat exchangers to separate hydrogen, C2−, and C3+ hydrocarbons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cryogenic separation systems are used to separate hydrogen from light hydrocarbons, then separation is achieved, but multiple refrigeration packages are required leading to high capital expenses and operational complexity
Solution Approach 1:
The patent combines multiple refrigeration functions into a single integrated refrigeration package that serves both the cryogenic separation system and the deethanizer column. This merging eliminates the need for separate refrigeration systems, reducing capital expenses and operational complexity while maintaining effective separation of hydrogen from light hydrocarbons and fractionation of C2- from C3+ hydrocarbons
Solution Approach 2:
The single refrigeration package is designed to perform multiple functions: cooling the cryogenic separation system to separate hydrogen from light hydrocarbons, and cooling the deethanizer column for fractionation of C2- from C3+ hydrocarbons. This multi-functional approach replaces multiple specialized refrigeration systems with one universal system, reducing overall system complexity
2Reliability
If conventional cryogenic separation systems are used with multiple deethanizer columns, then fractionation is achieved, but capital expenses and operational complexity increase
Solution Approach 1:
The patent integrates the deethanizer column directly with the cryogenic heat exchanger, combining what would traditionally be separate units into one integrated system. This merging eliminates the need for multiple deethanizer columns while maintaining effective fractionation of C2- hydrocarbons from C3+ hydrocarbons, thereby reducing capital expenses and operational complexity
3Temperature
If steam reboiling is used in conventional systems, then heating is achieved, but operational complexity and costs increase
Solution Approach 1:
The system uses the cold refrigerant stream from the cryogenic heat exchanger to provide reboiling duty for the deethanizer column. Instead of requiring an external steam reboiling system, the refrigeration system serves itself by utilizing its cold stream to heat the column, thereby eliminating the need for separate steam generation equipment and reducing operational complexity
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 capital expenditure by 14%, operational expenses by 16%, and equipment count by 42%, while enhancing the recovery of propylene and propane to 99.5-99.8% purity.
Implementation Method 1
condensing the deethanizer column overhead with a refrigerant stream in a cryogenic heat exchanger
Implementation Method 2
condensing the deethanizer column overhead with a refrigerant stream
Implementation Method 3
A refrigerant compressor may provide refrigerant to the deethanizer overhead cryogenic condenser and a main cryogenic heat exchanger
Implementation Method 4
separating the C2− material from the C3 hydrocarbons in the dehydrogenation effluent in a deethanizer column
Data Source
AI summary
An improved process and apparatus integrate a deethanizer column with a cryogenic heat exchanger by condensing the deethanizer column overhead with a refrigerant stream in a cryogenic heat exchanger. A refrigerant compressor may provide refrigerant to the deethanizer overhead cryogenic condenser and a main cryogenic heat exchanger. Expansion of the refrigerant may provide sufficient cooling duty in one or both cryogenic exchangers.