Advanced Materials Research Vols. 1010-1012

Abstract: In order to solve the problems of one-sidedness of current researches in classification of fly ash, degree of fineness, vitreous body, ignition loss, K₂O, SO₃ and CaO are chosen as the index properties to analyze projection pursuit classification method after analyzing chemical constituents and physical properties that influence the quality of fly ash. Targeting on the activity characteristics, the thesis establishes a projection pursuit cluster analysis model and makes a program on the basis of MATLAB. Population migration algorithm is adopted to seek an optimal projection direction. Fly ash is classified in accordance with property index value of the projection. Researches have proved that the model overcomes the shortcomings of traditional classification methods and reflects the quality and performance of fly ash in a comprehensive way. The evaluation is simple with accurate results and provides a scientific basis for the comprehensive utilization of fly ash.

Abstract: In this paper, Fe²⁺、Mn²⁺、Zn²⁺、Al³⁺ were joined in the biological trickling filter circulation fluid. The result indicated that catalyzed oxidation and the biological methods simultaneously purified SO₂ and NOx of the flue, the flow amount of import gas was more obvious than the other SO₂ and NOx gas purification effect influence. The SO₂ and NOx purification mechanism of aqueous catalyzed oxidation and biological law was discussed.

Abstract: Based on CO₂-NaOH system, the absorption performances and the mass transfer of the rotating packed bed with the three different types of the gas-liquid distribution inducer were investigated. The experimental results showed that the structure of the gas-liquid distribution inducer have an important effect on the volumetric mass transfer coefficient and the absorptivity of CO₂. Due to the enhancement of the countercurrent contact between the liquid phase and the gas phase from the installation of the distribution inducer, an increasement of the volumetric mass transfer coefficient and a higher absorptivity of CO₂ could be obtained than those of the experiment in PRB without any inducers. Among the distribution inducers, the combination of the liquid distribution inducer of Type-B and the gas distribution inducer of Type-A could give a better volumetric mass transfer coefficient and a higher absorptivity of CO₂, which were 27.84×10^-3 s^-1 and 80.00%, respectively.

Abstract: The paper expounds the principles and technology of earthworm decomposition of urban living garbage, analyzes the key factors influencing the earthworm activity and decomposition of urban household garbage. The experimental results show that the earthworm processing waste suitable conditions are 23-27 °C for temperature, 60%-80% for humidity, 6-8 for the soil pH. Visible, pH and temperature have much effect on the earthworm activity, when pH< 5.0 or pH > 8.0, or when the temperature is less than 0°C or more than 35°C, the earthworms can't basically survive. The introduction of the earthworm treatment makes the secondary fermentation of compost greatly shorten the processing cycle. At the same time earthworms’ decomposing garbage significantly increases the soil fertilizer effect.

Abstract: The effects of different raw material ratios on straws and vegetable wastes co-composting were investigated in pilot scale. The evolution of physical property (temperature, pH value, electrical conductivity (EC)) and nutrient substance (total carbon content (TC), total phosphorus content (TP), total nitrogen content (TN), C/N ratio) of composting were measured in order to research effects of different raw material ratios on the quality and maturity of composting products. Results showed that The temperature of P3 can reach above 50 ^o C for 5 days and the time of high temperature for P3 was longer than P1 (2 d) and P2 (4 d). Compared with P1 (8.23 ms/cm) and P2 (7.63 ms/cm), the final EC value of P3 was 7.33 ms/cm which was lowest of the three piles and P3 had the lowest resistance on plants. At the end of the composting process, TC of P1, P2 and P3 have decreased about 30%, while the content of TN and TP has not changed significantly. The initial C/N ratio of P3 was 23.33, and the final C/N ratio was 12.08. Results indicated that the mass ratios of straw and vegetable waste on 7:3 was the most effective to compost and the compost quality and maturity of P3 was best among the three piles.

Abstract: The principle and methodology of effluent treatment by iron-carbon micro electrolysis were introduced in the paper. Then design of the orthogonal experiments for dyeing effluent treatment was formulated. Discussion of influences of related factors on effluent treatment followed. Results were got after the detailed analysis. Therefore, we deduced the mechanism that the cations of Transition Metal (TM) and rare earth (RE) assist of zero-valent irons catalyzing degradation of dyeing effluent. The mechanism is formed based on the following explanation. Cations of manganese and cobalt easily penetrate Fe⁰ lattices, while Ce⁴⁺ cations do it difficultly because of their larger radius. Thus Ce⁴⁺ is weaker than both of Mn²⁺ and Co²⁺ for helping zero-valent irons to improve their activity. Furthermore, because the valence electron structure of Mn²⁺ is more stable than that of Co²⁺, Mn²⁺ is better for assisting zero-valent iron catalysis of degradation of dyeing effluent than Co²⁺. Therefore, ranking of influence for zero-valent iron catalysis activity from greatest to smallest is Mn²⁺, Co²⁺ and Ce⁴⁺.

Abstract: The process of biodrying could be a good solution for municipal solid waste management, allowing the production of fuel with an interesting energy content. In this study, bio-drying the mixed municipal solid waste (with the size among 15-80 mm) with different aeration modes were conducted. During the experiment, temperature, oxygen content and moisture content were determined, and continuous measurements of H₂S and CH₄ were taken. The results indicated that the thermophilic phases of all treatments beside T1 were met the Chinese standard of >55°C for 5-7 days for sanitation. The aeration mode of T4 was in favor of reduced the H₂S and CH₄ emission during MSW bio-drying. Under the condition of this study, the bio-drying cycle should be determined for 18 days. Intermittent ventilation mode is more effective to reduce the moisture content in MSW bio-drying process. So the aeration mode of T4 (2.0L/min, 30min run/30 min stop) was the first choice during MSW bio-drying.

Abstract: Along with the speeding up of urbanization and the improvement of people's quality of life, city garbage as a core part of the city sanitation engineering in recent years, more and more get the attention of the government. In our country, kitchen waste as part of the city garbage, the manufacturing quantity more and more. Science of processing the rubbish can not only protect the environment and people's health, but also for resources to use again. Through the survey of domestic processing of kitchen waste, put forward the domestic city for reasonable deal with the necessity of kitchen waste.

Abstract: silica aero-gels were synthesized from coal fly ash at ambient pressure. The experimental procedure for silica aero-gels production included alkali dissolution of fly ash, surface hydrophobic treatment of the wet-gel, followed by drying of the wet-gel samples at ambient pressure wasinvestigated. Optimized experimental parameters for production of silica aero-gels from fly ash were obtained through systematic studies. BET, SEM and FTIR and contact angle measurement were used in order to investigate the structure and characteristics of the silica aero-gel powders.

Abstract: An experimental study on co-pyrolysis of municipal solid waste and corn stalk was performed in a fixed-bed reactor under atmospheric pressure. The effect of different blending ratio on the pyrolysis product yields and compositions of the gaseous products was investigated. The results indicated that there exist synergetic effects in the co-pyrolysis of municipal solid waste and corn stalk. Under the different blending ratio conditions, the char and liquid yields were lower than the theoretical values calculated on pyrolysis of each individual municipal solid waste and corn stalk, and consequently the gas yields were higher. H₂ and CH₄ obtained co-pyrolysis at 800°C-900°C of 40% blending ratio conditions were higher than those of municipal solid waste and corn stalk alone.