诱导结晶反应器运行性能研究

以含铜废水为处理对象,将流化床和固定床两种诱导结晶反应器进行对比试验。结果表明:当进水含铜浓度为20 mg/L时,流化床反应器出水含铜量为0～2 mg/L,出水含铜量在0～11 mg/L;利用SEM-EDS可以发现,流化床形成的结晶产物生长致密、晶形明确、产物纯度高,固定床形成的结晶产物在载体表面分布不均、结构疏松,纯度较低。     

Regulation of soil enzyme activities in constructed wetlands under a short-term drying period

The activities of extracellular enzymes are important in understanding decomposition of soil organic matter in wetlands subjecting to drying. The activity of soil extracellular enzymes (β-glucosidase, N-acetylglucosaminidase, and phosphatase), and related physicochemical parameters were monitored in constructed freshwater wetlands during a one-month drying manipulation. Drying increased redox potential and decreased soil water content significantly (P<0.05). Higher content of soil organic matter (P<0.05) and higher concentrations of inorganic N (nitrate, P<0.01; and ammonia, P<0.001) were also observed significantly under drying condition. Soil hydrolase enzyme activities were stimulated significantly (β-glucosidase, P<0.05; N-acetylglucosaminidase, P<0.01; and phosphatase, P<0.001), and a two-phase pattern of enzyme activities was revealed under drying condition. The increase of soil enzyme activities under drying condition was significantly related to soil redox potential (P<0.001). Drying strongly affected soil enzyme activities only when soil water content remained above an optimal level for enzymatic catalysis (higher than 23% w/w), corresponding to redox potentials below 250–300 mV. Our results suggest that, under drying condition, potential enzyme activities may be regulated by redox potential, in respect to soil moisture, and consequently alter nutrient availability in wetlands.     

Suspended solid abatement in a conical fluidized bed flocculator

With the random movement of silica gel beads in a conical fluidized bed, micro-vortices resulting from the fluidization promoted the collision and aggregation of suspended fine kaolin powders. The abatement efficiencies of the suspended fine solids under several hydrodynamic conditions were studied, and a suitable control strategy for operating the conical fluidized bed flocculators was identified. The suspended solids abatement efficiency was found to increase with increasing Camp Number and flocculation time (T), but decreased with the increase of velocity gradient (G) within the range studied in this research (165.1–189.6 s^-1). The abatement efficiencies were all more than 60% at the range of G = 165–180 s^-1 and T = 15–33 s at an initial kaolin solid concentration of 150 mg·L^-1, polymer aluminum chloride dosage of 60 mg·L^-1 and sedimentation time of 20 min. However, the formation of flocs was influenced by the liquid backmixing. Excessive backmixing caused the breakup of flocs and resulted in difficulty for the fine powders to aggregate and sediment to the reactor bottom. The results of the calculated fractal dimension and measured free sedimentation velocity of flocs obtained at different runs showed similar flocs properties, and indicated an easy control strategy for sedimentation of the flocs.     

湖北省风能资源的高分辨率数值模拟试验

利用边界层模式CALMET耦合中尺度模式MM5对湖北省的风能资源分布特征进行数值模拟,得到水平分辨率1 km、 垂直高度10~150 m覆盖全省的风能资源分布。通过与测风塔对比发现,模式对九宫山7月、 11月的逐时有效风速的模拟相关系数分别为0.59、 0.57;受下垫面复杂地形的影响,10 m高度上的误差最大,50 m高度的模拟效果好于其他高度。70 m高度上数值模拟风速年均误差为7.21%,逐月平均风速误差范围在6.62%~7.30%之间。全省风能资源的总体分布特征是:中东部大于西部,西部的等值线相对凌乱且密集,冬、 春季风速、 风功率大于秋季,西部地区为风资源较贫乏地区。数值模拟结果虽然存在一定的误差,但模拟得到的风能资源分布趋势是符合本地区气候和地形特征变化规律的,可以作为制定区域风电发展规划的科学依据。在进行风电场选址时,对于误差大于平均水平的地区需要多布设测风塔。     

2×300 MW机组烟塔合一方案大气环境影响分析

受机场附近160 m限高制约,辽宁某电厂需采用烟塔合一技术. 运用德国AUSTAL2000模型分析了环境风速、大气稳定度、烟气出口速度、烟气出口温度等参数与烟气抬升高度间的关系,预测了烟塔排放的大气环境影响,并且与烟囱方案的大气环境影响进行了对比分析. 结果表明,各类参数变化均会导致烟气抬升高度发生改变. 环境风速不变,稳定度从A变到F时,抬升高度明显变小,最多可降低84.2%;相同稳定度条件下,环境风速从0.1 m/s增至4.4 m/s时,抬升高度明显变小,最多可降低84.3%;烟气出口速度从2.5 m/s增至8.0 m/s,抬升高度显著增加,最多为2.4倍;烟气出口温度从20 ℃增至50 ℃时,烟气抬升高度显著增加,最多为3.3倍. 综合经济及环保因素,该项目烟塔高度取130 m较适宜. 相比210 m烟囱方案,烟塔方案不仅满足机场限空要求,并且污染物年均及日均最大地面浓度均较低.      

某厂炼钢区域煤气超标原因分析

某钢铁厂一炼钢区域在3个月内多次发生煤气超标报警,但难以准确发现事故原因。事故调查组全面收集报警资料,深入一炼钢区域检查,查找分析煤气超标原因,排除了炉顶部位煤气泄漏、煤气设备密封不严泄漏、带煤气作业以及系统异常情况下紧急放散等可能因素,得出煤气报警与炼钢转炉煤气熄火放散存在较大关联的结论,并组织了柜前事故煤气管放散和转炉放散塔熄火放散或燃烧不充分模拟实验,实验结果与分析结论一致。最终给出了完善煤气放散点火系统、增加红外线火焰温度监测报警的技术对策和管理措施。     

高层住宅建筑火灾人员疏散仿真研究

基于高层建筑火灾的严重危害,本文在具体分析阐述我国目前高层住宅建筑的户型设计现状后,以长沙市某高层塔式住宅建筑为研究对象,利用人员疏散软件Building EXODUS(V4.06版)和烟气模拟软件CFAST对发生火灾后建筑物的人员疏散和烟气流动情况仿真模拟。研究表明,逃生楼梯的设计位置对高层塔式住宅的人员疏散效率影响较大;在发生紧急情况后,事前是否进行过疏散演习和事中的人工干预引导疏散对保障高层住宅建筑火灾居民的生命安全尤为重要;高层住宅建筑火灾,起火楼层越底,伤亡越大。     

GGH换热元件结垢堵塞原因分析及防治措施

京隆发电公司脱硫系统运行过程中经常发生GGH换热元件结垢和堵塞现象,分析了GGH结垢和堵塞的原因,主要包括除雾器除雾效率差;脱硫系统水平衡设计不合理;除雾器冲洗水系统故障、设计不当或冲洗不足;吸收塔补充石灰石浆液量过大;GGH换热元件波形板或GGH换热面高度设计不合理;吹灰系统设计不合理;氧化风量不足;吸收塔液位长时间保持在高液位、消泡剂添加不足;燃煤硫分的变化及吸收剂品质不好等。提出了防治措施,较好地解决了GGH换热元件结垢和堵塞的问题。     

烧结机湿法烟气脱硫吸收塔本体设计与应用

依据烧结烟气的特性,选用旋流板塔为脱硫吸收设备并对其结构进行设计。通过工程实例说明设计的塔型具有脱硫效率高、液气比低、运行费用低等优点,是一种值得应用于烧结机烟气脱硫的装置。     

基于污染物变化选择干化污泥处置技术

为了解我国城市污水厂污泥干化前后污泥含水率、pH值、总磷、总氮、有机质和重金属含量(Zn、Cu、Cr、Pb、Ni、As、Cd)的变化情况并据此选择合理的干化污泥处置技术,以我国某污泥干化厂三种类型的污泥样品为研究对象,并测定上述六项指标。结果表明:污泥干化后含水率降至3.72%;pH值降低至5.95和5.93;干化后干料中总氮、总磷和有机质的增加量分别为30%、2.7%和5%,而湿料的增加量分别为24.5%、10.7%和2.2%;重金属含量的变化与干化后污泥类型有关,湿料中重金属含量有所减少,而干料中重金属含量则有增有减。污泥干化厂应以湿料作为主要的干化产品。同时,对比样品中各指标的实测值与污泥标准中的控制限值可知,干料适合制砖、制水泥熟料和混合填埋,而湿料适于农用、土地改良和园林绿化。