| Authors |
Amir Shooshtari, University of Maryland, College Park, U.S.A.; Radoslaw
Kuzmicki, Mannheim University of Applied Sciences, Frankenthal, Germany;
Serguei Dessiatoun, University of Maryland, College Park, U.S.A.; Mohamed
Alshehhi, Petroleum Institute, Abu Dhabi, U.A.E.; Ebrahim Al-Hajri, Petroleum
Institute, Abu Dhabi, U.A.E. and Michael Ohadi, University of Maryland, College
Park, U.S.A.
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| Source |
Carbon Management Technology Conference,
7-9 February 2012,
Orlando, Florida, USA
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| Preview |
Abstract
Carbon dioxide (CO2) is the largest volume contributor and the fastest growing
component of greenhouse gases. Based on current technology the only
commercially available process that can absorb a reasonable amount of CO2 from
flue gases is chemical absorption. The other techniques are generally less
energy efficient and more expensive. Microchannel technology can be used to
enhance the mass transfer rate by increasing surface-to-volume ratio and
improving the thermal controllability of the absorption process. In the current
study we investigated the performance of microchannel contactors for absorption
of
CO2 in aqueous diethanolamine (DEA). A series of experiments was performed to
measure CO2 absorption rate and removal efficiency for various gas-to-amine
flow rate ratios. The rate of absorption was determined based on the variation
of electrical conductivity of the aqueous DEA due to the CO2 absorption
process. The effect of contactor length was studied for 200, 500, and 800 mm
long microchannels. The pressure drops of two-phase flow for various flow rate
ratios and
microchannel length were measured. The results demonstrated high potential of
the microchannel contactors for enhancement of the absorption process.
Introduction
The removal of acidic gases such as carbon dioxide from gas streams is an
important process in the process industry. For example, in gas sweetening at
least 4% by volume of raw natural gas consists of CO2, which must be reduced to
2% to prevent pipeline corrosion, to avoid consuming excess energy for
transport, and to increase heating value. Aaron and Tsouris [1] reviewed
various methods for the separation of CO2 from flue gas and provide a ranking
of various methods. They ranked CO2 separation based on membrane diffusion as
the most promising method. However, they noted that the technology is still at
the research and development stage, and it is still a challenge to find the
material that can operate at high enough temperatures. The second most
promising separation method, according to their ranking, was absorption. Based
on current technology, the only commercially available process that can absorb
a reasonable amount of CO2 from flue gases is chemical absorption. However, the
absorber columns used in industry are generally bulky and require large amounts
of expensive
amines to operate.
Numerous studies have focused on improving gas-liquid reactor performance via
process intensification. In recent years, microreactors featuring two-phase
flow in well-defined microchannel structures with diameters in the order of
microns to hundreds of microns have received significant attention from
industrial and academic communities because of their potential for enhancement
of mass and heat transfer. These microreactors offer several advantages over
their conventional counterparts. They feature high surface-to-volume ratios,
leading to high interphase mass transfer rates, and they provide superior heat
transfer control and thermal management. In addition, they can lead to
substantial reductions in reactor volume and the amount of chemicals
required.
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