新型碳质催化剂用于NH3选择性催化还原NOx的研究

以城市污水处理厂剩余污泥为原料制备了一种新型碳质催化剂。通过试验考察了催化剂在NH₃选择催化还原NO中的应用效果。结果表明,催化性能较好，最佳的制备和催化反应条件为：锌铁物质的量比1∶0.5，热解温度750 ℃，反应温度400 ℃，O₂浓度15%。在此条件下，NOx的最大转化率达98.3%。通过考察证明催化剂自身具有一定的还原性能。对催化剂进行了FTIR、TG、SEM和BET分析，结果表明，催化剂具有很丰富的孔结构、活性粒子和表面官能团，比表面积较大，最大可达307 m²·g^-1，分析结果显示具有良好的催化条件。     

Curing process of powdered phenol–formaldehyde resol resins and the role of water in the curing systems

The curing behavior of two kinds of commercial powdered resol phenolic resins was studied by differential scanning calorimetry. Liquid‐state ¹³C‐NMR spectroscopy was used to aid in understanding the curing behavior by detecting the structure of powdered resins. The reaction mechanism was interpreted with the dependency of activation energy on the degree of conversion. The results indicate that there are differences in the curing mechanism between core and face phenolic resins. The curing process of core resin was faster than that of face resin at the same reaction temperature. The water added in the curing system played an important role of plasticizer or diluent according to different curing stages and water content. In the initial curing stage, water mainly diluted the system and retarded the curing reactions. However, at the higher degrees of conversion, water played the role of plasticizer to decrease the effect of diffusion on the curing reactions to make the curing reactions more complete. The excess water added in the curing system played the role of diluent at almost all stages during the curing process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1371–1378, 2003     

Rheological properties of bitumen in water emulsions with added solids

Experimental work was carried out to investigate the rheological properties of bitumen in water emulsions containing solids of different shape and size. The bitumen volumetric concentration was varied up to 60%, solids free basis, and the solids volume fraction (total volume basis) was varied up to 0.2. Irregular-shaped silica sand (average diameter: 9 and 33 μm) and smooth spherical glass beads (average diameter: 27 and 44 μm) were used as the added solids. In the low shear stress range, shear thinning behavior was observed for bitumen in water emulsions. At high shear stress, the viscosity of the emulsions became fairly independent of the shear stress. The addition of solids to the bitumen emulsions increased the mixture viscosity. The addition of irregular-shaped silica sand gave a higher viscosity than a similar addition of the spherical glass beads. The viscosity of the emulsion/solids mixtures was influenced by the solids size as well; the smaller size particles gave a higher viscosity. The addition of solids to the bitumen emulsions also induced shear thickening (dilatancy) behavior at high solids volume fraction. The degree of the shear thickening increased with the oil concentration.     

The influence of soil properties on the effectiveness of phenylphosphorodiamidate (PPD) in reducing ammonia volatilization from surface applied urea

Urea can be an inefficient N source due to rapid hydrolysis by soil urease leading to NH₃ volatilization. The current study investigated the effect of the urease inhibitor phenylphosphorodiamidate (PPD) incorporated at two concentrations (0.5% and 1% w/w) within the fertilizer granule on NH₃ volatilization from surface applied urea. The daily rates of NH₃ loss from 20 soils of widely differing properties from Northern Ireland were measured over 14 days using ventilated enclosures under simulated spring conditions. Cumulative loss rates were calculated and fitted to a logistic model from which total NH₃ loss (Amax) and the time to maximum rate of loss (Tmax) were determined. Stepwise multiple linear regression analysis related the effectiveness of PPD in reducing NH₃ volatilization from urea to soil properties.The total cumulative loss of ammonia from unamended urea varied from 0.37 to 29.2% depending on soil type. Ammonia volatilization appeared to be greatest on a soil with a high pH (R² = 0.65), a low titratable acidity (TA) (R² = 0.63) and a soil that was drying out (R² = 0.50). Soil pH was negatively correlated with TA (r = –0.826, P < 0.001) suggesting that soils with a low TA may have received recent lime. Including cation exchange capacity (CEC) and % N as well as pH-KCl in the multiple linear regression equation explained 86% of the variance.The effectiveness of PPD in reducing Amax varied between 0% to 91% depending on soil type, the average over all 20 soils being 30 and 36% for 0.5% and 1% PPD respectively. The most important soil properties influencing the effectiveness of the urease inhibitor were soil pH-H₂O and TA accounting for 33% and 29% of the variance respectively. PPD was less effective on a soil with a high pH and low TA. These were the soil conditions that led to high NH₃ volatilization from unamended urea and may explain why PPD had limited success in reducing ammonia loss on these soils. Multiple linear regression analysis indicated that 75% of the variation in the % inhibition of NH₃ loss by PPD could be significantly accounted for by pH-H₂O, initial soil NO ₃ ^- -N concentration, % moisture content and % moisture loss.The delay in Tmax by PPD ranged from 0.19 to 7.93 days, the average over all 20 soils being 2.5 and 2.8 days for 0.5% and 1% PPD respectively. TA, % moisture content, urease activity and CEC were soil properties that significantly explained 83% of the variation in the % delay in Tmax by PPD in multiple linear regression analysis. However, none of these soil properties were significant on their own. As urea hydrolysis occurs rapidly in soil, delaying Tmax under field conditions would increase the chance of rain falling to move the urea below the soil surface and reduce NH₃ volatilization. A urease inhibitor should be more effective than PPD on soils with a high pH and low TA to be successful in reducing high NH₃ losses.     

过氧乙酸的合成与杀生作用研究

以乙酸和过氧化氢为原料合成了新型水处理杀生剂——过氧乙酸．并考察了过氧乙酸的贮存稳定性及稳定剂8-羟基喹啉的影响。通过细菌测试瓶法测细菌总数，研究了过氧乙酸杀生效果与投加浓度、pH值和作用时间之间的关系。结果表明：过氧乙酸作为水处理剂具有杀生速度快、杀生效果好的特点，是一种具有良好应用前景的水处理杀生剂。     

工业含磷废水除磷研究

在常温条件下，以低廉的氯化镁、碳酸氢铵作沉淀剂加入到含磷废水中除磷时，得到的一次处理液因含磷高无法达标排放。本文利用聚合氯化铝（PAC）和聚丙烯酰胺（PAM）作复合混凝剂，对其进行进一步除磷研究，实验研究证明，加入复合混凝剂的效果优于单独使用，并可使处理后的废水达到国家二类水排放标准。     

Pyrolysed carbon supported cobalt porphyrin: a potent catalyst for oxidation of hydrogen sulfide

Pyrolysed carbon supported cobalt porphyrin, an electrocatalyst that is frequently used for oxygen reduction in fuel cells, is evaluated for catalytic oxidation of hydrogen sulfide by dissolved dioxygen. The catalyst performs best after heat treatment at 880 °C_, at pH 8. Analysis of the reaction products reveals that sulfur is the dominant product throughout the investigated pH range 5–10. The catalyst performs much better than powdered activated carbon, granular activated carbon and different other forms of unmodified carbon catalysts. This is as far as we know the first time that heat treated cobalt porphyrins are evaluated for non-electrocatalytic applications.     

压力流化床燃烧煤水混合燃料泵送给料技术在国外的研究进展

压力流化床燃烧技术近二十年来在世界上得到很大发展。煤的湿法给料系统具有比干法输送系统更简单，运行调节更可靠等优点。煤水混合物可泵送的水分在２５％左右，煤的粒度一般为０～６ｍｍ，表现为非牛顿的假塑性流体特性，通过级配来达到一定的稳定性和良好输送性能，且流动阻力低，不用添加剂即可实现泵送，它的应用使压力流化床的燃烧制备和输送系统成本大大降低。     

Characterization of the reactivity of limestones with SO2 in a fluidized bed reactor

The reaction between SO₂ and calcined limestone particles has been studied in a fluidized bed combustor. Measurements of sorbent reactivity with SO₂ were made for small batches of limestone injected into the combustor. Simultaneous continuous combustion of bituminous coal provided conditions like those of a boiler for study of the sulphation reaction. A semi-empirical rate model of the CaO-SO₂ reaction has been developed. External mass transfer of SO₂, diffusion within the particles and chemical reaction are taken into account. The limestone reactivity with SO₂ is characterized by two parameters which are dependent on the temperature and sorbent particle size. A model for predicting the limestone requirements in a fluidized bed boiler has been developed. Parameters from the batch experiments are included. The predictions for sulfur retention agree with the experimental results. In addition, effects of operating conditions (gas velocity, recycle, limestone particle size) on the retention of SO₂ were simulated using the model.     

循环冷却水系统无垢低腐蚀率的技术改进

泸天化公司大氮肥循环冷却水系统投用以来，经优选水稳剂配方、改进加氯方式、增设旁滤池、提高补充水质量等措施，年腐蚀率从0．3366mm降至0．0241mm，换热器运行一年无结垢现象。