Ning Ping

Adsorption purification of HCN in closed carbide furnace tail gas by modified activated carbon

For comprehensive utilization of CO contained in closed carbide furnace tail gas, the purification of HCN in the artificial tail gas mixed with pure gases was studied by means of adsorption using modified activated carbon. In range of this study the optimum conditions for preparing modified activated carbon are: NaOH concentration is 10 wt% and sulfonated cobalt phthalocyanine (CoPcS) concentration is 166.7 mg/L for activated carbon impregnation; its dryness temperature is 100°C. Scanning electron microscopy (SEM) and Raman spectroscopy analyses indicate that HCN reacts on the surface of the modified activated carbon. The equilibrium adsorption capacity increases, however the structure of CoPcS has not been changed.

Simultaneous Removal of H2S and Dust in the Tail Gas by DC Corona Plasma

The removal of hydrogen sulfide and dust simultaneously by the DC corona discharge plasma with a wire-cylinder reactor was studied at atmospheric pressure and room temperature. The outlet gases were analyzed by Fourier Transform Infrared. Chemical compositions of the dust collected from ground electrode were analyzed by X-ray fluorescence. The results showed that the DC corona discharge is effective in removing H2S and dust simultaneously. The best H2S conversion was gained with the 2xa0cm discharge gap. The lower inlet H2S concentration, the higher conversion efficiency was gained at any specific input energy (SIE), while the energy yield was on the contrary. The removal efficiency of H2S decreased gradually as oxygen concentration increased, which means that the H2S decomposition mainly depends on direct electron collisions or short-living species, such as·O, ·OH radicals in the non-thermal plasma. At the initial stage, the conversion efficiency of H2S increased with the increasing of relative humidity, but later decreased while the relative humidity keep increasing with the same SIE. Existing of dust can not only reduce the energy consumption of H2S conversion and improve the removal efficiency, but also inhibit the yield of SO2 for it can further react with some compounds in the dust. With the discharge gap of 2xa0cm, inlet H2S concentration of 2400xa0ppm, O2 Of 0.5xa0%, relative humidity of 41xa0%, dust content of 4000xa0±xa05xa0%xa0mg/m3 and SIE of 600xa0J/L, the H2S conversion reached 98.8xa0%, and the dust removal efficiency was close to 100xa0%.

Hydrogen Sulfide Removal from Yellow Phosphorus Tail Gas by Wet Oxidation Process Combined with Activated Carbon

In order to utilize yellow phosphorus tail gas, deep desulfurization(hydrogen sulfide contained less than 1mg/m3) technologies are needed. In this study, purification of H2S in yellow phosphorus tail gas was investigated by wet oxidation process combined with activated carbon, 8000m3/h scale industrialized experiment were carried out. The results show that HF and SO2 are almost removed in the alkali washing unit, but for H2S removal efficiency of only 19.1~34%, the outlet concentration of H2S is 6959~13864mg/m3. Desulfurization by wet oxidation, the concentration of H2S could be less than 60mg/m3, Vanadium-based and 888 (phthalocyanine compounds) catalysts have the highest activity for H2S. At last, a industrialized experimental on the removal of P4, PH3 and H2S from yellow phosphorus tail gas by activated carbon catalytic oxidation technology was carried out. After purification through the catalyze bed, the concentrations of impurities in the product gas were able to meet the pre-treatment standard and the concentration of P4, PH3 and H2S would be decreased to less than 1 mg/m3. Along-term test for more than 300 h was carried out, the results show that the catalytic oxidation process is feasible and stable for activated carbon catalyst.

Adsorption of low concentration carbon disulfide in representative industrial off-gas by impregnated activated carbon

A absorbent was chose to absorb CS<inf>2</inf> from industrial activated carbon (AC), 13X, NaY, ZSM-5. The results indicate that the adsorption of CS<inf>2</inf> of the industrial activated carbon is better than the others. The modification of industrial activated carbon (AC) has been used in laboratory in order to make full use of high concentration CO comprehensively. AC was impregnated with Cu(Ac)<inf>2</inf>, Zn(Ac)<inf>2</inf>, Mn(Ac)<inf>2</inf>, Co(Ac)<inf>2</inf> and Ca(Ac)<inf>2</inf>. It is Cu(Ac)<inf>2</inf> for the optimum pregnant, 20°C for optimum reacting temperature, and 400°C for optimum cremating temperature. The fresh activated carbon and modified activated carbon before and after modification with Cu(Ac)<inf>2</inf> were characterized by SEM. The results show that the result of adsorption became obviously better by the change of pore structure of modified activated carbon and the formation of surface active materials.