Propane Recovery Configuration Using High-Pressure Deethanizer Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional natural gas liquids recovery processes are costly, energy-intensive, and complex, often failing to exploit the economic benefits of high feed gas pressure, leading to inefficient propane recovery and high energy consumption.
Innovation Solution
The process involves chilling and expanding high-pressure feed gas to produce a C2+ depleted vapor and a C2+ enriched liquid, where the vapor is combined with residue gas and the liquid is further expanded to provide cooling, eliminating the need for external refrigeration and costly equipment like turboexpanders, and operating the deethanizer at a pressure of 500-700 psig to achieve efficient propane recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional high propane recovery processes are used with propane refrigeration and turbo expanders, then propane recovery exceeds 95%, but capital cost and energy consumption become very high
Solution Approach 1:
The invention extracts and eliminates the turbo expander and associated refrigeration systems from the conventional process. By using a simple deethanizer column operating at elevated pressure (500-700 psig) without complex refrigeration, the process achieves acceptable propane recovery (50-80%) while dramatically reducing energy consumption and capital cost.
Solution Approach 2:
The invention changes the operating pressure parameter of the deethanizer column to 500-700 psig, which is higher than conventional operations. This parameter change allows the column to achieve adequate separation without requiring the low temperatures and complex refrigeration systems of conventional processes, thereby reducing energy consumption while maintaining acceptable propane recovery.
2Use of energy by stationary object
If demethanizer pressure is increased to reduce residue gas compression horsepower, then energy consumption decreases, but fractionation becomes difficult due to decreased relative volatilities
Solution Approach 1:
The invention optimizes the deethanizer operating pressure to a specific range (500-700 psig) that balances two competing requirements: high enough pressure to minimize residue gas compression horsepower and reduce energy consumption, but not so high that relative volatilities between components become too low for effective fractionation. This optimized pressure parameter enables both energy efficiency and acceptable separation performance.
3Use of energy by stationary object
If medium propane recovery (50-80%) is used instead of high recovery, then capital and operating expenses are reduced, but propane recovery efficiency decreases
Solution Approach 1:
The invention operates the deethanizer at elevated pressure (500-700 psig) without complex refrigeration, achieving a deliberate balance where propane recovery is in the 50-80% range rather than maximizing it to over 95%. This parameter optimization reduces capital and operating expenses while maintaining acceptable propane recovery levels that meet pipeline heating value requirements.
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 significantly reduces energy consumption and capital costs by minimizing residue gas compression and eliminating the need for external refrigeration, achieving propane recovery in the range of 50% to 80% with lower specific energy consumption compared to traditional methods.
Implementation Method 1
high-pressure feed gas is chilled and expanded to low temperatures to produce a C2+ depleted vapor and a C2+ enriched liquid
Implementation Method 2
condense a portion of the feed gas into a C2+ enriched liquid phase and a C2+ depleted vapor phase
Implementation Method 3
the liquid is further expanded to generate additional cooling
Data Source
AI summary
High-pressure feed gas is chilled and expanded to condense a portion of the feed gas into a C2+ enriched liquid phase and a C2+ depleted vapor phase. The liquid phase is expanded to provide additional cooling for the feed gas and deethanizer reflux prior to being fed to the deethanizer while the vapor is combined with residue gas of a deethanizer.