Energy & Fuels, Vol.33, No.7, 6650-6658, 2019
Performance of Bimetallic Additives (Fe-Co, Mn-Co, Cu-Co, and Zn-Co) Modified Na2S/AC Deoxidizers in Removal of O-2 from Low-Concentration Coalbed Gas
In this study, the deoxidizer Na2S was modified by different transition bimetals (Fe-Co, Mn-Co, Cu-Co, and Zn-Co) and Fe-Co ratios as auxiliary. The obtained deoxidizers were characterized by X-ray diffraction, N-2 adsorption/desorption, X-ray photoelectron spectroscopy, and H-2-TPR; their deoxidizing activity for the removal of O-2 from low-Concentration coalbed gas (CBM) were studied. Results showed that reactive oxygen species (O -) pound Content in Na2S deoxidizer, as well as unit effective deoxidization capacity (Q(O2)) and-Conversion rate of (C-Na2s), increased after modification with Fe-Co, Mn-Co, and Cu-Co. The higher the O - pound Content in deoxidizers, the higher the activity of the deoxidizers for the removal of O-2 from CBM was. Fe/Co Na2S/activated carbon (AC) had the highest amount of O - pound Content, larger pore volume, and less impurity species with small crystal size, and this made it the largest Q(O2) (63.74 mL/g) and C-Na2S (87.24%) at 200 degrees C and 1 atm. Although the deoxidizer Zn/Co-Na2S/AC modified with Zn-Co had larger O - pound Content, Q(O2) and C-Na2S of this deoxidizer is the lowest due to the presence of more impurities CoS2, CoO, and NaOH with larger crystal size on its surface. These impurities blocked the pores of the deoxidizer Zn/Co-Na2S/AC and inhibited both mass transfer and reaction of reactants through the material, resulting in declined activity. The deoxidizer Fe/Co (0.33/1)-Na2S/AC showed higher deoxidizing activity when the Fe-Co ratio was 0.33/1.