Article pubs.acs.org/IECR
Mass Transfer Performance of CO2 Absorption from Natural Gas using Monoethanolamine (MEA) in High Pressure Operations Hairul N. Abdul Halim,†,‡ Azmi M. Shariff,*,† Lian S. Tan,† and Mohammad A. Bustam† †
Department of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Malaysia School of Bioprocess Engineering, Universiti Malaysia Perlis, Kompleks Pusat Pengajian Jejawi 3, 02600 Arau, Perlis Malaysia
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ABSTRACT: Most carbon dioxide (CO2) absorption studies that use amine based solvents for flue gas treatments were conducted at atmospheric pressure. This study reports the absorption performance of monoethanolamine (MEA) for the removal of CO2 from natural gas (NG) at high pressure conditions. The absorption experiments were conducted in an absorption column packed with Sulzer metal gauze packing at 5.0 MPa operating pressure. The effects of gas flow rate (18.89− 35.08 kmol/m2·h), liquid flow rate (1.81−4.51 m3/m2·h), MEA concentration (1.0−4.0 kmol/m3), and liquid temperature (27− 45 °C) on the mass transfer performance were evaluated in terms of CO2 removal (%) and overall volumetric mass transfer coefficient (KGav). From this study, the KGav was found to increase with increasing liquid flow rate and MEA concentration. However, the mass transfer performance was not affected by the total gas flow rate. The optimum condition for liquid temperature was found to be at 40 °C.
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INTRODUCTION Natural gas (NG) is a fossil fuel which consists of combustible mixtures of hydrocarbon gases such as methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), pentane (C5H12), and impurities such as carbon dioxide (CO2), oxygen (O2), nitrogen (N2), and hydrogen sulfide (H2S) as well as rare gases (argon, helium, xenon). NG has a high energy conversion for power generation and emits low potentially harmful byproducts to the atmosphere, making it one of the superior choices for fuel. Removing acid gases such as CO2 is an important step in natural gas purification technology because the presence of CO2 reduces its heating value. Furthermore, in the presence of moisture, CO2 may react with water to produce carbonic acid which would accelerate corrosion in the pipelines and process equipment. It must also be removed in order to prevent crystallization during cryogenic processes (liquefaction process). CO2 removal technologies include absorption, adsorption, membrane, and cryogenic separation. Among them, chemical absorption is the most established technology for CO2 removal due to its ability to effectively reduce CO2 concentration to the desired target. Amine-based solvent is the most preferred choice as it offers fast reactivity, thus reducing the capital cost by allowing the use of smaller process equipment compared to physical absorption. For flue gas treatment, numerous researches for CO2 removal via chemical absorption have been conducted at atmospheric pressure with low CO2 concentrations (
