Contents lists available at ScienceDirect International Journal of Greenhouse Gas Control journal homepage: www.elsevier.com/locate/ijggc CO 2 capture from water-gas shift process plant: Comparative bench-scale pilot plant investigation of MDEA-PZ blend vs novel MDEA activated by 1,5- diamino-2-methylpentane Chikezie Nwaoha a, ⁎ , Paitoon Tontiwachwuthikul a, ⁎ , Abdelbaki Benamor b a Clean Energy Technologies Research Institute (CETRI), Faculty of Engineering and Applied Science, University of Regina, SK, S4S 0A2, Canada b Gas Processing Center, Qatar University, Doha, Qatar ARTICLE INFO Keywords: CO 2 capture MDEA PZ 1,5-Diamino-2-methylpentane Water-gas shift Hydrogen ABSTRACT This research is a bench-scale pilot plant investigation of novel amine solvent blend containing MDEA and 1,5- diamino-2-methylpentane (DA2MP) for CO 2 capture from water-gas shift process plant (H 2 production). The CO 2 concentration used in this study (50 vol.% CO 2 with N 2 balance) is similar to that of the water-gas shift product gas. The CO 2 capture performance of the MDEA-DA2MP blend was compared to the standard 3 kmol/m 3 MDEA- 0.5 kmol/m 3 PZ blend (34.4 wt.% MDEA-5 wt.% PZ). The low concentration of PZ in this study is because of the chemical toxicity of PZ and possible precipitation at medium to high concentration. The MDEA concentration in the MDEA-DA2MP blend was kept constant at 3 kmol/m 3 while the DA2MP was varied from 0.5 kmol/m 3 (6.75 wt.%) to 1.5 kmol/m 3 (20.3 wt.%). The pilot plant analysis was performed at a gas flow rate, amine so- lution flow rate, and reboiler temperature of 14 SLPM, 50 mL/min, and 120 °C respectively. Pilot plant results revealed that the higher MDEA-DA2MP blend concentration possesses higher CO 2 capture efficiency (up to 24%), higher CO 2 absorption rate (up to 23.5%) and higher absorber mass transfer coefficient (up to 23.9%) compared to the MDEA-PZ blend. It was also discovered that the high MDEA-DA2MP concentration has lower regeneration energy (up to 25.4%), lower initial amine solution utilized (up to 20.5%), lower desorber mass transfer coefficient (up to 32.5%) compared to the MDEA-PZ blend. However, the optimal amine concentration is the 3 kmol/m 3 MDEA-1 kmol/m 3 DA2MP blend. Overall results show that the MDEA-DA2MP blend can offer a cost-effective and energy efficient CO 2 capture compared to MDEA-PZ. 1. Introduction According to the International Energy Agency, the energy sector and the industrial processes not related to energy accounted for 68% and 7% respectively of the global greenhouse gas (GHG) emissions in 2016 (International Energy Agency, 2017). It was also reported that 90% of the GHG emissions are attributed to carbon dioxide (CO 2 ) (International Energy Agency, 2017). Also, the Environment and Cli- mate Change Canada revealed that the Canadian energy sector and industrial processes accounted for 81.25% and 7.53% respectively of 2016 GHG emissions by IPCC sector (Climate Change Canada, 2018). When classified by type of GHG, it was disclosed that CO 2 contributed 79% of Canada’s emissions by GHG (Climate Change Canada, 2018). Fig. 1 displays an industrial process known as the pre-combustion process and also referred to as integrated gasification combined cycle (IGCC). In the case of H 2 production (water-gas shift process), the carbonaceous material (natural gas, coal, hydrocarbon residues, coke, asphaltenes, hydrocarbon liquids, biomass, bio-liquids, glycerol etc.) is first gasified either in the presence of steam (steam reforming), oxygen (partial oxidation) or both (auto-thermal reforming) to produce syngas which is predominantly carbon monoxide (CO) and H2 (Eqs. (1) and (2))(Wood et al., 2012). The syngas also contains varying amounts of CO 2 (5%–15%) which will depend on the type of fuel that is gasified (Wang et al., 2009; National Energy Technology Laboratory (NETL), 2016). However, in order to produce more H 2 while eliminating the CO, the produced syngas is sent to the water-gas shift reactor (WGSR) for conversion of CO into CO 2 and H 2 (Eq. (3) and Fig. 1). + ↔ + endothermic CH H O CO 3H 4 2 2 (1) + ↔ + exothermic CH 0.5 O CO 2H 4 2 2 (2) + ↔ + exothermic CO H O CO H 2 2 2 (3) https://doi.org/10.1016/j.ijggc.2019.01.009 Received 25 August 2018; Received in revised form 11 December 2018; Accepted 13 January 2019 ⁎ Corresponding authors. E-mail addresses: nwaoha2c@uregina.ca, chikezienwaoha@live.co.uk (C. Nwaoha), paitoon.tontiwachwuthikul@uregina.ca (P. Tontiwachwuthikul). International Journal of Greenhouse Gas Control 82 (2019) 218–228 1750-5836/ © 2019 Elsevier Ltd. All rights reserved. T