A novel technique of flue gas desulphufization （FGD） using industrial sodium sulfide as absorbent is described to remove SO2 in flue gas. The FGD byproduct in this novel technique is sodium thiosuffate （Na2S2O3 ...A novel technique of flue gas desulphufization （FGD） using industrial sodium sulfide as absorbent is described to remove SO2 in flue gas. The FGD byproduct in this novel technique is sodium thiosuffate （Na2S2O3 · 5H2O, Hypo） which can be used as chemical raw material. Optimal operating parameters about this technique have been determined. In order to enhance productive efficiency of sodium thiosulfate, EDTA disodium additive is added into absorption solution to prevent oxidation of sodium thiosulfate. Its optimal concentration is 0. 02 wt. %. The pH value of absorption solution is set in the range of 5 ~ 6.5. Experimental results show that SO2removal efficiency averagely reach 98.72 %. The highest productive efficiency of sodium thiosulfate reaches 83.24 %. The sodium thiosulfate formed during FGD can be separated from saturated absorbent by filtration, concentration and crystallization. The filtrate after separating sodium thiosulfate will be reused as SO2 absorbent by replenishing some fresh sodium sulfide.展开更多
The alcoholic fermentation of substrates rich in free soluble sugars is well known and has been industrially developed. However, the production of second-generation ethanol from lignocellulosic biomass, which is abund...The alcoholic fermentation of substrates rich in free soluble sugars is well known and has been industrially developed. However, the production of second-generation ethanol from lignocellulosic biomass, which is abundantly available worldwide, remains under development. The aim of this study was to evaluate the possibility of using the Musa cavendischii banana tree pseudostem as a substrate for alcoholic fermentation. Hydrolisis methods using dilute sulfuric acid （1% and 2% H2SO4; 15 and 30 min; 90 ℃, 100 ℃ and 120 ℃） and enzymes （pH 5.5; and 45 ℃ for 24 h reaction time） were evaluated both separately and in combination. The effect of chemical pre-treatment of the substrate using 1% and 3% m/m NaOH （120 ℃, 15 min） was verified for both methods. The highest yield coefficient of fermentable sugars from dry biomass （Yrs = 74%） was obtained using enzymatic hydrolysis and pre-treatment with 3% NaOH. Using acid hydrolysis, the maximum yield obtained was 22% （1% H2SO4, 120 ℃, 30 min）. Fermentation of the hydrolysates was satisfactory, and the maximum yield of ethanol formed per unit of substrate consumed, total productivity and efficiency values were 0.35 g, 0.90 g ethanol L^-1·h^-1 and 65.9%, respectively. This demonstrates the utility of banana tree pseudostems in second-generation ethanol production.展开更多
To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies （Fe^2＋-EDTA and Fe^3＋-EDTA） and species （Fe-EDTA, F...To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies （Fe^2＋-EDTA and Fe^3＋-EDTA） and species （Fe-EDTA, Fe（OH）x^32x and FeC6H5O7） addition on cell growth and accumulation of astaxanthin were studied. Results show that different iron electrovalencies have various effects on cell growth and astaxanthin accumulation of H. pluvialis. Compared with Fe^3＋-EDTA, Fe^2＋-EDTA stimulate more effectively the formation of astaxanthin. The maximum astaxanthin content （30.70 mg/g biomass cell） was obtained under conditions of 18 μmol/L Fe^2＋-EDTA, despite the lower cell density （2.3×10^5 cell/ml） in such condition. Fe^3＋-EDTA is more effective than Fe^2＋-EDTA in improving the cell growth. Especially, the maximal steady-state cell density, 2.9×10^5 cell/ml was obtained at 18 μmol/L Fe^3＋-EDTA addition. On the other hand, all the various species of iron （EDTA-Fe, Fe（OH）x^32x, FeC6H5O7） are capable to improve the growth of the algae and astaxanthin production. Among the three iron species, FeC6H5O7 performed the best. Under the condition of a higher concentration （36 μmol/L） of FeC6H5O7, the cell density and astaxanthin production is 2 and 7 times higher than those of iron-limited group, respectively. The present study demonstrates that the effects of the stimulation with different iron species increased in the order of FeC6H5O7, Fe（OH）x^32x and EDTA-Fe.展开更多
基金This research project was sponsored by National Natural Science Foundation (20877026)
文摘A novel technique of flue gas desulphufization （FGD） using industrial sodium sulfide as absorbent is described to remove SO2 in flue gas. The FGD byproduct in this novel technique is sodium thiosuffate （Na2S2O3 · 5H2O, Hypo） which can be used as chemical raw material. Optimal operating parameters about this technique have been determined. In order to enhance productive efficiency of sodium thiosulfate, EDTA disodium additive is added into absorption solution to prevent oxidation of sodium thiosulfate. Its optimal concentration is 0. 02 wt. %. The pH value of absorption solution is set in the range of 5 ~ 6.5. Experimental results show that SO2removal efficiency averagely reach 98.72 %. The highest productive efficiency of sodium thiosulfate reaches 83.24 %. The sodium thiosulfate formed during FGD can be separated from saturated absorbent by filtration, concentration and crystallization. The filtrate after separating sodium thiosulfate will be reused as SO2 absorbent by replenishing some fresh sodium sulfide.
文摘The alcoholic fermentation of substrates rich in free soluble sugars is well known and has been industrially developed. However, the production of second-generation ethanol from lignocellulosic biomass, which is abundantly available worldwide, remains under development. The aim of this study was to evaluate the possibility of using the Musa cavendischii banana tree pseudostem as a substrate for alcoholic fermentation. Hydrolisis methods using dilute sulfuric acid （1% and 2% H2SO4; 15 and 30 min; 90 ℃, 100 ℃ and 120 ℃） and enzymes （pH 5.5; and 45 ℃ for 24 h reaction time） were evaluated both separately and in combination. The effect of chemical pre-treatment of the substrate using 1% and 3% m/m NaOH （120 ℃, 15 min） was verified for both methods. The highest yield coefficient of fermentable sugars from dry biomass （Yrs = 74%） was obtained using enzymatic hydrolysis and pre-treatment with 3% NaOH. Using acid hydrolysis, the maximum yield obtained was 22% （1% H2SO4, 120 ℃, 30 min）. Fermentation of the hydrolysates was satisfactory, and the maximum yield of ethanol formed per unit of substrate consumed, total productivity and efficiency values were 0.35 g, 0.90 g ethanol L^-1·h^-1 and 65.9%, respectively. This demonstrates the utility of banana tree pseudostems in second-generation ethanol production.
基金Supported by Xiamen Scientific and Technologic Projects (No. 3052Z20031086)Xiamen University Alumni Association Foundation in Singaporethe First National College Students Innovative Experimental Project
文摘To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies （Fe^2＋-EDTA and Fe^3＋-EDTA） and species （Fe-EDTA, Fe（OH）x^32x and FeC6H5O7） addition on cell growth and accumulation of astaxanthin were studied. Results show that different iron electrovalencies have various effects on cell growth and astaxanthin accumulation of H. pluvialis. Compared with Fe^3＋-EDTA, Fe^2＋-EDTA stimulate more effectively the formation of astaxanthin. The maximum astaxanthin content （30.70 mg/g biomass cell） was obtained under conditions of 18 μmol/L Fe^2＋-EDTA, despite the lower cell density （2.3×10^5 cell/ml） in such condition. Fe^3＋-EDTA is more effective than Fe^2＋-EDTA in improving the cell growth. Especially, the maximal steady-state cell density, 2.9×10^5 cell/ml was obtained at 18 μmol/L Fe^3＋-EDTA addition. On the other hand, all the various species of iron （EDTA-Fe, Fe（OH）x^32x, FeC6H5O7） are capable to improve the growth of the algae and astaxanthin production. Among the three iron species, FeC6H5O7 performed the best. Under the condition of a higher concentration （36 μmol/L） of FeC6H5O7, the cell density and astaxanthin production is 2 and 7 times higher than those of iron-limited group, respectively. The present study demonstrates that the effects of the stimulation with different iron species increased in the order of FeC6H5O7, Fe（OH）x^32x and EDTA-Fe.
