(522a) Absorption Global Standard - Standardisation of Mass Transfer Parameters in Absorption and Desorption

?Absorption
Global Standard'

Standardization
of mass transfer parameters in absorption and desorption

1.   
Motivation

Dimensioning of absorption and desorption columns is highly dependent
on applied mass transfer parameters, which need to be determined
experimentally. However, a partially significant deviation in the value of mass
transfer coefficients determined in the past has been observed, thus their
comparability is restricted. Based on deficient transparency, reasons for the variation
between mass transfer coefficient are often unknown. Consequently,
high safety factors for dimensioning of columns are necessary and following
high construction costs. Therefore, a standardization of mass transfer
measurements in absorption is essential for a consistent database of mass
transfer parameters. Hence, increasing application of rigorous mass transfer
models for absorption process design will be more effective. Due to the need of
standardization the project ?Absorption Global Standard' was launched in fall 2011. In this project
a consortium of universities, producers and users of packings
and absorption columns are involved.

2.   
Goals

The aim of this project is to develop a method for consistent experimental
determination of volumetric mass transfer parameters. In addition to the
experimental standardization of measurements, a mathematical method is
established that gives the opportunity to designate phase specific mass
transfer parameters and effective interfacial area. Based on this, transparency
in development of both methods is essential to guarantee global acceptance and
comparability of determined mass transfer parameters. For this purpose a
detailed description of experimental method will be published at the end of
this project. Additionally, a standardized mathematical method is summarized in
a tool and will be published along with the experimental method. Thus, database
for mass transfer coefficients become more reliable and safety factors decrease.
Hence, costs and resources for column design can be optimized. In this work
status quo of the project will be shown, with focus on the current state of
experimental method development.

3.   
Approach

The approach within this project can be classified into three periods.
The first period is a qualitative and quantitative analysis of the influence of
column configuration parameters and preparation parameters on hydrodynamic and
mass transfer results. Thereby, the following configuration parameters are
analyzed regarding their influence:

-      
Liquid
distributor

-      
Gas
distributor

-      
Packing
Height

-      
Sampling

-      
Demister

Additionally, the following preparation parameters are analyzed:

-      
Pretreatment
of packings

-      
Inserting
random packings

-      
Water
quality

In the second period of the project a standardized experimental method is
established. Therefore, characterization experiments with respect to the
results of the qualitative and quantitative analysis of the first period are
arranged. Those are carried out with selected structure packings
of Mellapak 250.Y and random packings
of Pall Ring 25 M and 50 M at different facility plants. For the estimation of
phase specific mass transfer parameters the standardized mathematical method is
used. The results will show the comparability of the standardized methods and
subsequently the determined mass transfer parameters.

In the third and last period an investigation of interactions between
experimental data and calculation pathway of the mathematical method is
performed. For this purpose, a detailed local and global sensitivity analysis
shows the influence of chemical system data for the standardized calculation
method regarding HTU-NTU evaluation.

This project is founded
by the
?Forschungs-Gesellschaft Verfahrens-Technik e.V.?, IGF-Vorhaben 17116N.