Sponge Absorber Vapor Routing for LPG Recovery
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Solution Overview
Problem
Conventional LPG recovery processes require excessive sponge oil due to hydrogen content in stripper net overhead vapors, which hampers absorption efficiency in sponge absorbers.
Innovation Solution
Separate cold and hot flash drum liquids are fed into respective strippers to produce distinct net overhead vapor streams, which are then routed to a sponge absorber at different tray locations, allowing for efficient separation and absorption of LPG using separate amine scrubbers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If combined overhead vapor from hot and cold strippers is routed to sponge absorber, then LPG recovery is achieved, but sponge oil requirement increases due to hydrogen content
Solution Approach 1:
The invention divides the combined overhead vapor stream into two separate streams: one from the hot stripper and one from the cold stripper. Each stream is routed to separate amine scrubbers for independent treatment, allowing selective removal of hydrogen from the hot stripper stream before both streams enter the sponge absorber. This segmentation enables the sponge absorber to operate with reduced hydrogen content, thereby reducing sponge oil requirements while maintaining absorption efficiency.
2Productivity
If separate amine scrubbers are used for hot and cold stripper vapors, then hydrogen content is reduced, but device complexity increases
Solution Approach 1:
The invention extracts the hydrogen removal function from the combined vapor stream by introducing separate amine scrubbers specifically for the hot stripper overhead vapor. This extraction approach isolates the hydrogen-rich stream from the LPG-rich stream, allowing targeted treatment of hydrogen without compromising LPG recovery. The separate scrubber configuration, while adding equipment, provides precise control over hydrogen removal and simplifies the overall process by eliminating the need for complex combined treatment systems.
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 sponge oil requirements by approximately 34-44% while maintaining LPG recovery, and decreases reboiler and condenser duties in associated equipment by 20-30%, enhancing overall process efficiency.
Implementation Method 1
a sponge absorber to recover a liquid petroleum gas output stream
Implementation Method 2
through an amine scrubber
Data Source
AI summary
A method for improving efficiency of sponge absorption includes providing cold flash drum liquid to an inlet of a cold stripper to produce a cold stripper net overhead vapor stream rich in liquid petroleum gas, and separately providing hot flash drum liquid to an inlet of a hot stripper to produce a hot stripper net overhead vapor stream rich in hydrogen. The cold stripper net overhead vapor stream and the hot stripper net overhead vapor stream are separately routed to a sponge absorber to recover a liquid petroleum gas output stream using sponge oil. In particular, the cold stripper net overhead vapor stream and the hot stripper net overhead vapor stream are separately routed to the sponge absorber at different tray locations.