Metal-Modified Active Coke for Simultaneous Removal of SO₂ and NO_x from Sintering Flue Gas

Abstract

A series of active coke (AC)-based adsorbents modified by different metal combinations (Na/Ba/Cu, Na&Cu/Na&Ba, and Na&Ba&La/Na&Ba&Ce), supporting different contents of metal and calcined at different temperatures, was investigated for simultaneous removal of SO2 and NO x . The activity test results showed that supporting 8% NaCO3, 7% Ba­(NO3)2 & 8% NaCO3, and 10% Ce­(NO3)2 & 7% Ba­(NO3)2 & 8% NaCO3 on the AC was best in unitary, bibasic, and ternary metal modifications, respectively. Supporting 10% Ce­(NO3)2 & 7% Ba­(NO3)2 & 8% NaCO3 was the best of all. The Fourier transform infrared spectroscopy result showed that the sodium modification made some unsaturated groups and metal chelate complexes form on the AC, so that the removal performance improved. Barium added to 8% Na–AC augmented the amount of unsaturated groups to improve the performance further. The addition of cerium to 7% Ba–8% Na–AC made more unsaturated groups and metal chelate complexes form, thus raising the performance again. The Brunauer–Emmett–Teller (BET) result showed that the unmodified (AC) and modified (10% Ce–7% Ba–8% Na–AC) ACs were predominantly microporous materials, and the pore size distribution and pore width of the modified AC was more extensive and multiple, which were beneficial for the removal of SO2 and NO x . Moreover, the removal performance improved significantly as the calcination temperature increased from 200 to 600 °C, whereas it slumped as the calcination temperature increased from 600 to 800 °C. It was explained by the results of X-ray diffraction and BET that CeO2, which was one of the active ingredients on the AC, increased with the increase of the calcination temperature and the higher the sample calcined at a temperature, the worse the pore structure of the carrier.

Regeneration/Optimization of Activated Carbon Monolith in Simultaneous SO2/NOx Removal from Flue Gas

“…Prior to the experiment, about 0.75 g of the adsorbent was placed in the center of the reactor and preheated under a nitrogen flow at 120°C for 30 min. Coal was burnt in an electric vertical furnace at 900°C to simulate real-life industrial flue gas generation, where a power plant furnace operates at > 800°C [12]. The flue gas was passed through the ACM-Co 3 O 4 adsorbent at a flow rate of 800 mL min -1 and column temperature of 150°C.…”

Enhancement of the denitrification efficiency over low‐rank activated coke by doping with transition metal oxides

“…A variety of modification methods are used to improve the denitrification performance of AC . The simplest and most commonly used method is to treat AC with nitric acid .…”

Simultaneous Removal of SO2 and NOx From Flue Gas by Low-temperature Adsorption Over Activated Carbon

“…By introducing NH3 to the flue gas, NOx can be reduced to N2 through catalytic reduction over activated carbon and a deNOx rate of about 70% can be achieved [11], which is not sufficient enough to meet the emission control requirement in power plant. Abundant of effort has been made to enhance the adsorbablility of SO2 and NOx by either using modified activated carbon [12,13] or other solid adsorbent such as activated carbon fibers [14], molecular sieve [15,16], alumina substrate impregnated with sodium carbonate (NOXSO process) [17], copper oxide [18], etc. But none of these technologies has been successfully commercialized.…”