Kyung-Seun Yoo

Simultaneous removal of SO2 and NO by sodium chlorite solution in wetted-wall column

The effect of feeding rate of NaClO2 solution, inlet SO2 and NO concentration, [NaClO2]/[SO2+NO] molar ratio (η), L/G ratio and, solution pH on the simultaneous removal of SOx/NOx has been investigated in a wetted-wall column. Both SOx and NOx removal efficiencies are enhanced with the increasing feeding rate of NaClO2 solution and attain a steady state. NOx removal efficiency increases with increasing SO2 concentration, but SOx removal remains unaffected with increasing NO concentration. In an acidic medium, DeSOx and DeNOx efficiency increased with increasing [NaClO2]/[SO2+NOx] molar ratio and attained a steady state. NOx removal starts only after the complete removal of SOx. The excess of NaClO2 does not enhance NOx removal efficiency. Solution pH does not affect the DeSOx and DeNOx efficiency. The maximum SOx and NOx removal efficiencies achieved at the typical operating conditions of commercialized FGD processes are about 100 and 67%, respectively.

Bio-oil upgrading over Ga modified zeolites in a bubbling fluidized bed reactor

Abstract Catalytic upgrading of bio-oil was carried out over Ga modified ZSM-5 for the pyrolysis of sawdust in a bubbling fluidized bed reactor. Effect of gas velocity (U o /U mf ) on the yield of pyrolysis products was investigated. The maximum yield of oil products was found to be about 60% at the U o /U mf of 4.0. The yield of gas was increased as catalyst added. HZSM-5 shows the larger gas yield than Ga/HZSM- 5. When bio-oil was upgraded with HZSM-5 or Ga/HZSM-5, the amount of aromatics in product increased. Product yields over Ga/HZSM-5 shows higher amount of aromatic components such as benzene, toluene, xylene (BTX) than HZSM-5.

Reactivity of bio-sorbent prepared by waste shells of shellfish in acid gas cleaning reaction

Acid gas cleaning activity of bio-adsorbent prepared by waste shell of different shellfish species was investigated in a fixed bed reactor to evaluate its feasibility as an acid gas cleaning agent. The physicochemical properties of prepared adsorbents were measured using ICP, BET, SEM-EDX and XRD. The results showed that active chemical species of bio-sorbent are comparable to that of commercial limestone and lime. SO2/NOx removal capacity of waste shell of shellfish was higher than that of commercial limestone due to the enhanced physical properties. In particular, the desulfurization activity of clam based adsorbent was the best among the tested waste shells because of both higher calcium content and more specific surface area. These lead to the conclusion that commercial limestone can be substituted for bio-sorbent prepared by waste shell of clam.

Adsorptive removal of atmospheric pollutants over Pyropia tenera chars

As a replacement for activated carbon, biochar was synthesized and used for the adsorptive removal of formaldehyde and nitrogen oxide. Biochar was produced from the fast pyrolysis of the red marine macro alga, Pyropia tenera. The P. tenera char was then activated with steam, ammonia and KOH to alter its characteristics. The adsorption of formaldehyde, which is one of the main indoor air pollutants, onto the seaweed char was performed using 1-ppm formaldehyde and the char was activated using a range of methods. The char activated with both the KOH and ammonia treatments showed the highest adsorptive removal efficiency, followed by KOH-treated char, ammonia-treated char, steam-treated char, and non-activated char. The removal of 1000-ppm NO over untreated char, KOH-treated char, and activated carbon was also tested. While the untreated char exhibited little activity, the KOH-treated char removed 80% of the NO at 50°C, which was an even higher NO removal efficiency than that achieved by activated carbon.

Production of Bio Oil by Using Larch Sawdust in a Bubbling Fluidized Bed Reactor

Fast pyrolysis experiments of larch sawdust by using a bubbling fluidized bed (0.076 m I.D. × 0.8 m high) have been investigated to determine, particularly, the effect of temperature, U o /Umf ratio, length/diameter ratio of bed (L/D), particle size of the bed material, and O2 concentration on the bio oil yield and compositions. The operation conditions were as follows: temperature, 350–550°C; L/D, 1.0–3.0; U o /Umf ratio, 2.0–6.0; particle size, 60–128 μm; and O2 concentration, 0–15 vol%. As bio oil yield decreased with operation conditions, the gas yield increased and the number of chemical compounds in bio oil decreased. The maximum oil yield of 58 wt% was obtained at: temperature, 400°C; L/D ratio, 2.0; and O2 concentration, 0%.