Packed Column Flood Point Optimization via Dimensionless Correlation
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Solution Overview
Problem
Current methods for determining flood points in packed distillation columns are complex and lack a unified mathematical expression for pressure drop across varying liquid flow rates, making it difficult to optimize product output and prevent column flooding.
Innovation Solution
A method is developed to determine flood points by providing a dataset of gas pressure drop values versus gas flow rates at different liquid flow rates, setting flood point values accordingly, and calculating an average fractional flood point value to minimize standard deviation, resulting in a plot or mathematical expression of pressure drop as a function of the flood point fraction at any liquid flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If current methods are used to determine flood points in packed distillation columns, then flood point determination can be performed, but the methods are complex and lack a unified mathematical expression for pressure drop across varying liquid flow rates
Solution Approach 1:
The patent transforms the complex multi-variable pressure drop problem into a simplified universal correlation by changing the parameters from absolute pressure drop values to dimensionless groups (Eu number, Reynolds number, Froude number). This parameter transformation enables a unified mathematical expression that adapts across varying liquid and vapor flow rates without requiring complex separate correlations for each condition.
Solution Approach 2:
The patent creates a universal pressure drop correlation that functions across all operating conditions (different liquid flow rates, vapor flow rates, and packing types) through a single mathematical expression. The Eu number correlation serves as a multi-functional tool that predicts pressure drop universally, eliminating the need for multiple separate methods or empirical adjustments for different operating scenarios.
2Device complexity
If a unified mathematical expression is developed for pressure drop, then the problem is simplified from three variables to two, but this requires minimizing standard deviation and iterative calculation of average fractional flood point values
Solution Approach 1:
The patent performs preliminary data normalization and dimensionless grouping before developing the final correlation. By pre-defining the Eu number, Reynolds number, and Froude number relationships, the complex iterative minimization process is replaced with a straightforward calculation procedure that directly computes pressure drop from the universal correlation without requiring repeated standard deviation minimization iterations.
3Measurement precision
If flood points are determined at different liquid flow rates, then accurate flood point prediction is achieved, but the lack of unified expression makes it difficult to optimize product output and prevent column flooding
Solution Approach 1:
The patent maintains flood point prediction accuracy by using dimensionless parameters (Eu number, Reynolds number, Froude number) that preserve the physical relationships across different scales and conditions. The parameter transformation allows accurate prediction at any liquid flow rate while enabling easy column optimization through the unified correlation, as engineers can directly calculate operating limits without complex multi-variable analysis.
Data Source
AI summary
A product output rate for a packed column is optimized by setting a desired product output rate from the distillation column, calculating a fraction of flood point of the distillation column at a reflux ratio, and determining a pressure drop value within the distillation column at the fraction of flood point. The step of determining the pressure drop employs the method of producing a plot of pressure drop as a function of fraction of flood point at any liquid flow rate, or producing a mathematical expression thereof. The method of optimizing a product output rate from a distillation column then includes calculating a pressure at a point in the distillation column for a pressure at a different point in the distillation column, calculating the pressure drop within the distillation column of a given length, calculating a temperature corresponding to the calculated pressure at a point in the distillation column, and adjusting the desired product output rate or the reflux ratio or the pressure at a different point in the distillation column.