Advances in Economics, Business and Management Research, volume 215
Proceedings of the 2022 7th International Conference on Social Sciences and
Economic Development (ICSSED 2022)
A Review of Pre-combustion Carbon Capture
Technology
Zexiong Chen1,*
1
College of Letter & Science, University of California, Santa Barbara, Santa Barbara, California, United States,
93106
*Corresponding author. Email: zexiong_chen@ucsb.edu
ABSTRACT
Global warming is one of the most significant challenges that people are facing today. As a result, capturing greenhouse
gases especially carbon dioxide becomes a necessary technology for releasing climate change. This paper mainly
focuses on introducing three physical solvents and processes, including Selexol Process, Purisol Process, and
Morphysorb Process, used in pre-combustion carbon capture. The paper finds that Selexol Process is a physical removal
process that uses the mixture of dimethyl ether and propylene glycol as the solvent to capture carbon dioxide and
hydrogen sulfide from the syngas. Purisol Process usually uses N-Methyl-2-Pyrrolidone as the solvent in the IGCC
power plant to capture carbon dioxide, hydrogen sulfide, and Carbonyl sulfide. Morphysorb process is a relatively new
process comparing to the other two processes. It uses N-Formylmorpholine and other morpholine derivatives to remove
CO2 and H2S.
Keywords: Carbon capture and storage, physical solvent, Selexol process,Purisol process,Morphysorb
Process
1. INTRODUCTION temperature will cause serious and unpredictable natural
disasters like droughts, storms, and rising sea level. In
In recent years, global warming, which is caused by this case people need to pay attention to the greenhouse
the accumulation of greenhouse gases like CO2 in the gases emission. To begin with, fossil fuels is an
atmosphere, is one of the most significant problems that extremely important and currently irreplaceable energy
different countries try to deal with. The rising source (figure 1 shows that fossil fuels have occupied 80%
of energy consumption in U.S.).
Figure 1 U.S. primary energy consumption by energy source
Copyright © 2022 The Authors. Published by Atlantis Press International B.V.
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Advances in Economics, Business and Management Research, volume 215
As a result, carbon capture and storge (CCS) plays a The pre-combustion carbon captures technique
really important role in tackling climate change at this mainly focuses on extracting carbon dioxide from fossil
stage. fuel or biomass fuel before the combustion processes
generate energy. Generally, this pre-combustion capture
Carbon capture and storage technology are not
technology is used in the process of gasification of coal,
mature and still need to spend a lot of time on research.
natural gas, and biomass, which can generate syngas and
Currently, many researchers are focusing on capturing
in natural gas power plants[1].
carbon dioxide by using bioenergy, such as using plant
waste like trunks. These topics are mainly focusing on Typically, a pre-combustion carbon capture system
finding new CCS technologies materials. This reseach is starts at the gasification of fossil or biomass fuels to form
focusing on some existing physical industrial carbon syngas, which contained mainly hydrogen, carbon
capture techniques. Giving a detailed review of these monoxide, and carbon dioxide. Usually, the syngas is
CCS techniques, can help factories managers to choose used to power the turbine generator and produce
which technologies they are going to choose. electricity, so pre-combustion carbon capture technology
usually extracts carbon dioxide out of the syngas before
The purpose of this paper is to list and discuss some
the gas is combusted in the turbine[1]. To achieve this,
existing physical pre-combustion carbon capture and
syngas is shifted to water-gas-shift (WGS) reactions,
storage technology. In the following discussion, three
which will create extra hydrogen and convert the carbon
physical carbon capture processes, including what
monoxide in syngas into extra carbon dioxide. The
solvents are used, how they capture acid gases, and the
increasing density of carbon dioxide after the WGS
overall working principles. This research can help
reaction will make the carbon capturing process be more
factories that want to lower their carbon emission and
effective. The whole procedures are shown in Figure 2.
also provide information about some existing physical
The post combustion capture, in general, has four aspects
solvents that are commercially used by scholars.
to study, including solvent-based carbon capture,
sorbent-based carbon capture, membrane-based carbon
2. PRE-COMBUSTION CAPTURE capture, and novel concepts[1].
Figure 2: Process diagram carbon capture and compression for an IGCC power plant[1]
3. SOLVENT-BASED CARBON DIOXIDE Institute (EPRI), the physical solvent can capture around
70% of carbon dioxide produced from the Integrated
CAPTURE
gasification combined cycle (IGCC) power generation
At present, physical solvents are widely used in many facilities and have only 4% lost[2].
industrial manufacturing processes, such as synthesis gas, Generally, there are some existing commercial
natural gas, hydrogen production and other industries. processes that used physical solvents to extract carbon
When carbon dioxide is under great pressure, usually dioxide. For instance, the Selexol Process uses dimethyl
more than 10 bar[1], physical solvents are used to capture ether or propylene glycol to capture both carbon dioxide
carbon dioxide. Physical solvents usually have a larger and hydrogen sulfide under a low temperature condition.
absorption limit than chemical solvents under a large The Purisol process, which uses N-Methyl-2-Pyrrolidone
pressure condition. Proven by Electric Power Research as a solvent in the IGCC power generation facilities to
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Advances in Economics, Business and Management Research, volume 215
withdraw carbon dioxide from the syngas. Morphysorb The selexol process is a physical acid gas removal
process, a relatively new process, usually employs N- process that uses the mixture of dimethyl ether and
Formylmorpholine and other morpholine derivatives as propylene glycol as the solvent to selectively capture
solvents to extract carbon dioxide and hydrogen sulfide. carbon dioxide and hydrogen sulfide out of the syngas.
Usually, we call Selexol a dual-stage process. The
4. THREE TYPES OF PROCESS hydrogen sulfide will be removed at the first stage, then
the carbon dioxide will be removed at the second stage.
4.1Selexol Process The overall principle of the selexol process can be shown
in the following figure.
Figure 3: Simplified process flow chart of the Selexol process configuration[1]
The high-pressure syngas at the beginning will enter removed. The CO2 containing syngas will travel to the
the H2S absorber at 40 Celsius. Almost 20% of the total CO2 absorber and produce clean syngas.
solvent in the H2S absorber is recirculated from the CO2
absorber[1]. The H2S concentrator’s main function is to 4.2 Purisol process
accumulate H2S. When the H2S absorber is heated to
around 100 Celsius, it will then travel to the H2S Purisol process usually adopts N-Methyl-2-
concentrator. Inside the concentrator, nitrogen gas will Pyrrolidone as the solvent in the IGCC power generation
be injected to separate the absorbed carbon dioxide in facilities to withdraw carbon dioxide from the syngas at
solvent and then flow back to the H2S absorber. The H2S high pressure and high content of CO2 and eliminate the
in reserve will be sent to the concentrator and then be Carbonyl sulfide impurity. The overall operation flow
chart is shown in the following figure.
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Advances in Economics, Business and Management Research, volume 215
Figure 4:optimal Purisol Process for IGCCI
In the beginning, in the H2S absorber, some H2S and Morphysorb process usually utilizes N-
CO2 are removed from the injecting raw gas. The Formylmorpholine and other morpholine derivatives to
solvents will be adjusted to a low pressure then pass remove the bulk of CO2 and H2S out of the natural gas
through the reabsorber (selectively absorb H2S) before it and other gas streams in factories. The Morphysorb
is recycled to the main gas stream. Then the acid gas like process’s first commercial application is in DEGT Gas
carbon dioxide and hydrogen sulfide will be totally Transmission, Canada. A plant built in the Pine River
removed by the reboiled stripping operation. The gas area is used to remove acid gas. It can remove 50
from the Hot Flash, which is purified and recycled, will MMscfd of carbon dioxide and hydrogen sulfide and
be sent to an oxygen-blown Claus unit. The Claus unit generate 1,050 long tons/day of elemental sulfur at a
will generate some tail gas that contains H2, CO, H2O, recovery rate of 99%[1]. Another typical application is
and CO2, as well as any untreated H2S and SO2. Finally, The Kwoen Gas Plant located also in Canada, focusing
the tail gas will be sent to a hydrogenation part and the on reducing the acid gas generated in the Pine River Gas
remaining sulfur compounds will be converted to Plant. The following flow chart shows how the Kwoen
hydrogen sulfur. The tail gas will be also cooled to Plant utilizes the Morphysorb process to capture carbon
remove water and the remaining carbon dioxide. dioxide and hydrogen sulfide.
4.3 Morphysorb process
Figure 4: Process Flow Diagram for Kwoen Plant[1]
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Advances in Economics, Business and Management Research, volume 215
The gas that contains carbon dioxide and hydrogen capture and storage, ScienceDirect, 1 December
sulfide will be absorbed into two absorbers. In the first 2016, Page 1633-1663
and second Recycle Flash Drum, the Morphysorb solvent [4] National Energy Technology Laboratory,
will be consecutively flashed and the flash gas will be
Pre-Combustion CO2 Capture,
compressed and recycled to absorber feed to avoid
methane gas loss. In the third and fourth Recycle Flash https://netl.doe.gov/coal/carbon-capture/pre-
Drum, they will generate the acid gas that will be combustion
compressed and liquefied to the downhole. Finally, the
[5] National Energy Technology Laboratory,
Morphysorb solution will flow back to the absorbers.
Pre-Combustion CO2 Capture,
5. CONCLUSION https://netl.doe.gov/coal/carbon-capture/pre-combustion
Capturing carbon dioxide and other acid gases is a [6] National Energy Technology Laboratory, Pre-
significant step for releasing climate change. Currently Combustion CO2 Capture,
carbon capture technology has three areas of studies,
https://netl.doe.gov/coal/carbon-capture/pre-combustion
which are pre-combustion capture, post-combustion
capture, and oxy-combustion capture. Pre-combustion [7] Kathryn A.Mumford, Yue Wu, Kathryn H. Smith,
capture technology is a relatively mature domain Geoffrey W.Stevens, Review of solvent based
compared with the other carbon capture technologies. In carbon-dioxide capture technologies, Higher
the area of pre-combustion, the most frequently used and Education Press and Springer- 22 June 2015
mature process is the Selexol process. The Selexol
[8] Kathryn A.Mumford, Yue Wu, Kathryn H. Smith,
process uses a mixture of dimethyl ether and propylene
Geoffrey W.Stevens, Review of solvent based
glycol as the solvent to absorb H2S and CO2. The paper
carbon-dioxide capture technologies, Higher
finds that, a process of simulation shows that the Selexol
process can reach 95% of carbon capture efficiency[1]. Education Press and Springer- 22 June 2015
Besides, the Purisol process and Morphysorb process are [9] Omid Ashrafi, Hamed Bashiri, Amin Esmaeili, Hristo
also widely used in industry. The Purisol process usually Sapoundjiev, Philippe Navarri, Ejector integration
adopts N-Methyl-2-Pyrrolidone as the solvent in the
for the cost effective design of the SelexolTM
IGCC power plant to capture CO2, H2S, and COS. It is
process, ScienceDirect, 1 November 2018, Page
well suited in high pressure and high content of CO2
380-392
conditions. The Morphysorb process is first
commercially applied in 2002, which is a relatively new [10] Omid Ashrafi, Hamed Bashiri, Amin Esmaeili,
process. This process mainly uses N-Formylmorpholine Hristo Sapoundjiev, Philippe Navarri, Ejector
and other morpholine derivatives to remove the bulk of integration for the cost effective design of the
CO2 and H2S from the injected gas stream. These three SelexolTM process, ScienceDirect, 1 November
processes are the most typical and widely used physical 2018, Page 380-392
process. Their main restriction is these three processes
[11]https://www.google.com/search?q=Physical+Solve
can only be used on a large scale in factories, which is
nts+for+Acid+Gas+Removal+chapter+4&oq=Phys
not a good sign in releasing the carbon capturing.
ical+Solvents+for+Acid+Gas+Removal+chapter+4
However, currently, an area that focuses on using waste
&aqs=chrome..69i57j33i160l2j33i299.2677j0j7&s
like woods, peanut shells, and Walnut shells, etc. to
capture CO2 has a lot of developing potentials. This post- ourceid=chrome&ie=UTF-8//.
combustion capturing technique can be achieved on a http://kinampark.com/PL/files/Kohl%201997%2C
smaller scale and most importantly, using waste to %20Physical%20solvents%20for%20acid%20gas
capture CO2 can greatly lower the cost of carbon %20removal.pd
capturing and utilize this technology on a bigger scale. [12] Nagaraju (Raj) Palla,Dennis Leppin, Technical and
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