Research Article
A Sensitive Method Approach for Chromatographic Analysis of
Gas Streams in Separation Processes Based on Columns Packed
with an Adsorbent Material
I. A. A. C. Esteves,
1
G. M. R. P. L. Sousa,
2
R. J. S. Silva,
3
R. P. P. L. Ribeiro,
1
M. F. J. Eusébio,
1
and J. P. B. Mota
1
1
LAQV, REQUIMTE, Departamento de Qu´ ımica, Faculdade de Ciˆ encias e Tecnologia, Universidade Nova de Lisboa,
2829-516 Caparica, Portugal
2
Saudi Basic Industries Corporation (SABIC), P.O. Box 5101, Riyadh 11422, Saudi Arabia
3
Instituto de Biologia Experimental e Tecnol´ ogica (iBET), Apartado 12, 2781-901 Oeiras, Portugal
Correspondence should be addressed to I. A. A. C. Esteves; iaesteves@fct.unl.pt
Received 1 February 2016; Accepted 19 May 2016
Academic Editor: Fernando Lusqui˜ nos
Copyright © 2016 I. A. A. C. Esteves et al. Tis is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
A sensitive method was developed and experimentally validated for the in-line analysis and quantifcation of gaseous feed and
product streams of separation processes under research and development based on column chromatography. Te analysis uses a
specifc mass spectrometry method coupled to engineering processes, such as Pressure Swing Adsorption (PSA) and Simulated
Moving Bed (SMB), which are examples of popular continuous separation technologies that can be used in applications such as
natural gas and biogas purifcations or carbon dioxide sequestration. Tese processes employ column adsorption equilibria on
adsorbent materials, thus requiring real-time gas stream composition quantifcation. For this assay, an internal standard is assumed
and a single-point calibration is used in a simple mixture-specifc algorithm. Te accuracy of the method was found to be between
0.01% and 0.25% (-mol) for mixtures of CO
2
, CH
4
, and N
2
, tested as case-studies. Tis makes the method feasible for streams with
quality control levels that can be used as a standard monitoring and analyzing procedure.
1. Introduction
Adsorption separation is a phenomenon in which one or
more components of a fuid (adsorbate) are extracted via
selective bonding to a solid (adsorbent) medium [1–3]. Tis
is the basis for every adsorption separation process. Periodic
adsorption processes, such as single or multibed Pressure
Swing Adsorption (PSA), have been extensively developed
and applied in industry for gas separation and are energy
efcient alternatives to other separation techniques such as
cryogenic distillation. Much progress has been achieved in
improving their performance with respect to both the process
economics and the attainable purity of the products by inves-
tigating new process confgurations or giving a better reuse to
some topical waste gases like biogas produced from biomass
[4]. Simulated Moving Bed (SMB) is a continuous adsorptive
separation process with various applications, many of which
are difcult to handle using other techniques. Recently, the
feasibility of SMB operation for gas separation has been
addressed and its feasibility demonstrated, with focus on
cyclic modulation of the internal fow rates [5, 6].
Long gone are the days where the development of SMB
and PSA process schemes and their experimental validation
were analyzed by manual and discrete sampling quantifca-
tion chromatographic techniques. Nowadays, for the appli-
cations of interest the coupling of the separation/purifcation
process unit with a spectrometry system can be done through
a capillary line, in order to bring the required continuous
sample streams into the analyzer at the specifed pressure,
while maintaining the high vacuum necessary for proper
spectrometry operation. For mixtures where the identifca-
tion of the masses of individual atoms and molecules that
have been ionized are possible to distinguish, mass spec-
trometry (MS) is a reasonably simple but unique technique
Hindawi Publishing Corporation
Advances in Materials Science and Engineering
Volume 2016, Article ID 3216267, 9 pages
http://dx.doi.org/10.1155/2016/3216267