湿法烟气脱硫喷淋塔的持液特性

在喷淋塔内部增设湍流装置是提高脱硫效率的有效途径之一,因此以自行设计的湍流装置的冷态喷淋塔为对象,考察了气速、喷淋量、液气比(L/G)、湍流装置水平和垂直间距对其持液特性的影响。实验结果表明,当湍流装置结构形式一定时,液体在塔内的停留时间随气速的增大而增大,随喷淋量、L/G的增大而减小;湍流层的持液量随气速、喷淋量、L/G的增大而增大;当气速、L/G一定时,液体在塔内的停留时间和持液量均随湍流装置水平和垂直间距的增大而减小。当气速、喷淋量、L/G、湍流装置水平和垂直间距分别为3.6 m·s~(-1)、100m~3·h~(-1)、10 L·m~(-3)、X_1、Y_1时,液体的最大停留时间为24.58s;而当气速、喷淋量、L/G、湍流装置水平和垂直间距分别为m~3·h~(-1)、25 L·m~(-3)、X_1、Y_1时,湍流层的最大持液量为1.093 m~3。对实验数据进行多元线性回归分析,得出该湍流式喷淋塔持液量的经验公式,其拟合优度与显著性良好,对工业应用具有一定的参考价值。     

滤料粒径对给水曝气生物滤池运行稳定性的影响

利用给水曝气生物滤池(UBAF)处理刘屋洲水源水,考察了不同陶粒粒径对氨氮、高锰酸盐指数的去除效果以及水头损失变化的影响。结果表明,陶粒3～5 mm的UBAF对氨氮、高锰酸盐指数的去除效果较高,但是其水头损失较大,且反冲洗前后水头损失变化偏大,不利于UBAF稳定运行。陶粒6～10 mm的UBAF运行状况良好,氨氮的去除率为73.8%,高锰酸盐指数的去除率为18.6%,滤池24 h过滤水头损失<0.4 m,反冲洗前后过滤水头损失变化量<5 cm。其出水氨氮和高锰酸盐指数均达到《生活饮用水卫生标准》(GB5749-2006),滤池的水头损失小,反冲洗前后也变化甚微。进一步的实验表明陶粒破碎会导致滤料粒径级配变化,使得水头损失增加。     

铁碳微电解响应面优化预处理染料废水

在单因素实验的基础上,以色度和COD去除率为评价指标,染料废水的初始pH值、铁碳比以及反应时间为考察因素,采用Box-Behnken方案构建与拟合响应曲面模型,通过该模型分析了这3个独立变量以及变量之间的交互作用对色度和COD去除率的影响,并确定了最佳工艺,即当控制曝气量9.42 L/min时,pH值为3.5,铁碳比为0.75,反应时间为35 min,COD和色度的去除率分别达到83.1％和87.8％,回归模型的预测值和测定值偏差率分别为0.7％和0.4％.     

黑曲霉固态发酵三七渣产纤维素酶

考察了硫酸铵添加量、磷酸二氢钾添加量、三七渣粒径、培养基含水率等因素对黑曲霉固态发酵三七渣产纤维素酶的影响,并采用正交实验对培养基制备条件进行了优化。研究结果表明,三七渣作为发酵培养基用于生产纤维素酶是可行的;含水率、硫酸铵添加量、磷酸二氢钾添加量以及三者之间的交互作用对实验结果的影响极显著(P0.01),这3个因素以及它们之间的交互作用对实验结果影响程度的排序为:硫酸铵添加量含水率磷酸二氢钾添加量交互作用;优化的培养基制备条件为:采用过80目的筛三七渣,硫酸铵添加量为40 mg/g干药渣,磷酸二氢钾添加量为10 mg/g干药渣,初始含水率为55%,pH值自然,在此条件下发酵,所产CMC酶活可达73.23 IU/g湿物料。     

上向流曝气生物滤池水头损失沿程分布与动态特性

对比考察了天然斜发沸石、页岩陶粒和石灰岩碎石填料曝气生物滤池的水头损失增长规律,分析了3种滤池水头损失的空间分布特征和动态变化特性,探讨了截留固体累积量对水头损失发展的影响规律。结果表明,沸石、陶粒和石灰岩曝气生物滤池均具有较好的有机物和SS沿程去除能力,并与水头损失的沿程分布密切相关;滤池内部TSS的沿程变化趋势和水头损失沿程分布趋势基本一致;曝气生物滤池的水头损失随着反应器运行时间的延长而缓慢增加,当滤床内TSS积累量增加到一定程度时,气体的滤床驻留率增加,并与TSS积累协同作用,滤床局部孔隙率迅速下降,水头损失迅速越升。曝气生物滤池的反冲洗首先应着眼于解决滤床的局部孔隙率过低问题,然后以气洗促进颗粒碰撞,气水联合提高剪切力,最后水漂洗排出TSS和气泡。     

上向流曝气生物滤池反冲洗实验研究

为进一步探讨水头损失、反冲洗条件及反冲洗效果之间的关系，在前期理论分析的基础上，对天然斜发沸石、页岩陶粒和石灰岩碎石填料等3座曝气生物滤池的水洗、气洗和水漂洗等基本反冲洗过程进行了优化研究，考察了反冲洗后滤池水头损失的恢复情况以及反冲洗对处理效能的影响。结果表明,反冲洗后初滤出水的COD和SS稍有增加，但很快就在2 h...     

铁电极活化过硫酸盐对金橙G的降解

研究了铁电极活化过硫酸盐(EC/PDS)产生的具有强氧化性的硫酸根自由基(SO_4~-·)对溶液中金橙G(orange G,OG)的氧化降解行为。重点考察了电流强度、PDS投加量、金橙G初始浓度、溶液初始pH值以及共存阴离子对金橙G降解速率的影响。实验结果表明:相比单独絮凝(EC)和投加过硫酸盐(PDS),EC/PDS体系能够有效地去除金橙G;金橙G的去除效率随着电流强度的增大而增大,随着PDS投加量的增大而增大,随着金橙G初始浓度增大而减小;较低的溶液pH值更利于OG的降解。水中共存阴离子对金橙G的降解存在着不同程度的抑制作用:PO_4~(3-)CO_3~(2-)Cl~-。此外,通过加入不同的淬灭剂(甲醇和叔丁醇),确定了体系中主要存在的自由基。     

pH值、离子强度和重金属离子对腐殖酸紫外谱图的影响

研究pH值、溶液离子强度和金属离子对腐殖酸紫外光谱的影响,分析腐殖酸的结构特征,探讨E3/E4与pH值和溶液离子强度的关系。结果表明,腐殖酸的紫外光谱吸收带,随pH值增大主要发生蓝移。但随溶液离子强度增大,pH值对腐殖酸紫外吸收带的影响逐渐降低直至不影响。随溶液离子强度增大,腐殖酸的紫外光谱吸收带都发生红移、吸收强度增大。且腐殖酸的E3/E4值与溶液离子强度具有显著的正相关性。腐殖酸的紫外光谱中的吸收带,随投加Cu2+或Cd2+浓度增大而发生红移。     

草甘膦模拟废水的纳滤分离过程研究

为研究草甘膦纳滤分离过程的影响因素及变化规律,选用GE Osmonic的DK膜对草甘膦模拟废水进行纳滤分离过程的研究。实验表明,20℃、浓度500 mg/L、pH=2.96的草甘膦模拟废水,其截留率随跨膜压力升高而略有升高,其渗透通量随跨膜压力的升高几乎线性增加;随操作温度升高渗透通量增加,但截留率下降;渗透通量和截留率均随料液初始浓度的增加而降低;在pH值为3~5的范围内,草甘膦的截留率随pH值升高而下降,在膜的等电点附近达到最低,该pH值范围内渗透通量在膜的等电点附近较高;在pH值为5~11的范围内,草甘膦的截留率随pH值升高而升高,在该pH值范围内渗透通量随pH值升高而降低;由于屏蔽效应,草甘膦的截留率随NaCl浓度的升高而降低。     

基于剪切乳化机的采油污水再现配置与分散相破碎乳化行为

以剪切乳化机为主体,设计、加工了一套采油污水室内再现配置装置,探讨了含油量、剪切强度(与流量同比变化,下同)等不同配置条件下的再现采油污水粒度分布、乳化度、Zeta电位和粘度等性能参数以及乳化机前后的压力损失.结果表明,该采油污水再现配置装置,能满足不同性质采油污水的配置要求,剪切乳化机的压力损失随着剪切强度的增大而明显升高,而随含油量增大没有明显的变化趋势,呈现出基本稳定的状态.较大的剪切强度创造了湍流流体条件,强化了分散相颗粒之间的碰撞聚结行为,因而再现采油污水的乳化度随剪切强度增大而降低,这种降低的程度又受含油量的影响:低含油量时剪切强度的影响明显,高含油量时这种影响逐渐减弱并趋于平缓.鉴于高含油量时趋于形成大粒径油珠,再现采油污水的乳化度随含油量增大而呈现略微的下降趋势,这种下降趋势的程度同时受剪切强度的影响:低剪切强度时含油量的影响较为明显,而高剪切强度时的剪切条件削弱了含油量的影响.Zeta电位随着剪切强度增大而不断增大,使得分散相颗粒带电绝对值降低,乳化体系有脱稳的趋势,导致颗粒间的碰撞聚结机会变大,与乳化度降低的趋势相吻合.剪切强度和含油量对再现采油污水粘度的影响不大.     

稻秆对铜绿微囊藻抑制作用的研究

研究了稻秆浸出液对铜绿微囊藻生长的抑制作用.研究表明,稻秆浸出液中含有的化学物质抑制了铜绿微囊藻的生长繁殖.稻秆浸泡时间的延长,有利于提高浸出液的抑藻效果,但浸泡时间过长则无益于抑藻效果提高,浸泡时间为15 d时,抑制率能高达75.99%.稻秆浸出液投加量达7.5%以上具有显著的抑藻效果.不同部位的水稻秸秆浸出液对铜绿...     

填料塔中Na_2CO_3吸收高浓度H_2S的传质特性

在填料吸收塔中考察了Na2CO3溶液吸收高浓度H2S气体的气液传质特性。通过测量填料塔进出口气体中H2S浓度计算了Na2CO3溶液吸收高浓度H2S气体的总体积传质系数(KGa),并研究了进气流速、吸收液流量、吸收温度和吸收液浓度对KGa的影响。结果表明,KGa随Na2CO3浓度、吸收液流量的增加而增加,随吸收温度、进气流速的升高而降低;在高浓度H2S吸收过程中液相传质阻力不能忽略。     

Characterization of urea SCR using Taguchi technique and computational methods

Use of biodiesel in diesel engine helps to reduce HC, CO, and smoke emissions due to their enormous oxygen content, whereas NOx emissions formed by Zeldovich mechanism shoot up. Implementation of Bharat Stage (BS) VI by April 2020 in India has created extreme pressure on automobile manufacturers to include after treatment technology in their systems. Selective catalytic reduction (SCR), a NOx control technology, is operated using aqueous urea solution as the reductant. There are several parameters that need to be monitored to enhance the NOx conversion efficiency of SCR retrofit. The uniformity index of ammonia, which determines the conversion efficiency, is greatly influenced by parameters like exhaust gas temperature, injection angle, injector position, mass flow rate, and SCR geometry. This paper considers two types of SCR design, namely SCR with and without mixer design and their impact on NOx reduction. The effect of mass flow rate on urea conversion in SCR design without mixer is 27%, but the impact is reduced greatly in SCR design with mixer with less than 2% variation. The UI resulting from different cases ranges from 0.59 to 0.83. Using Taguchi technique and CFD tool, the impact of parameters on both the SCR designs has been investigated and the optimum SCR design is reported.

     

响应面法分析优化牛粪厌氧发酵工艺参数

选取总固体浓度(TS)、碳氮比(C/N)和发酵时间(T)等3个发酵工艺参数,以沼气产率、甲烷含量和COD去除率作为发酵过程响应指标,运用响应面法(RSM)优化牛粪厌氧发酵工艺条件。结果表明,根据实验数据建立的3个二次多项式数学模型都具有高度耦合性(0.01),并且回归系数(R2)均大于0.9,说明预测值与实验值之间具有很好的拟合度。根据二次多项式方程运用响应面法单独优化沼气产率、甲烷含量和COD去除率的最优条件分别为TS=6.18%,C/N=25.51,T=34.12 d;TS=6.97%,C/N=25.81,T=36.45 d;TS=4.51%,C/N=24.86,T=36.08 d。结果发现,提高沼气产率和甲烷含量与提高COD去除率的最优TS和C/N值是相反的,进一步采用Design-Expert软件寻找出三者共同的优化条件,结果为TS=6.49%,C/N=25.36和T=35.37 d。该条件下沼气产率为230.62 mL/g VS,甲烷含量为70.50%以及COD去除率为57.51%。     

A computational technique for turbulent flow of wastewater sludge.

A computational fluid dynamics (CFD) technique applied to the turbulent flow of wastewater sludge in horizontal, smooth-wall, circular pipes is presented. The technique uses the Crank-Nicolson finite difference method in conjunction with the variable secant method, an algorithm for determining the pressure gradient of the flow. A simple algebraic turbulence model is used. A Bingham-plastic rheological model is used to describe the shear stress/shear rate relationship for the wastewater sludge. The method computes velocity gradient and head loss, given a fixed volumetric flow, pipe size, and solids concentration. Solids concentrations ranging from 3 to 10% (by weight) and nominal pipe sizes from 0.15 m (6 in.) to 0.36 m (14 in.) are studied. Comparison of the CFD results for water to established values serves to validate the numerical method. The head loss results are presented in terms of a head loss ratio, R(hl), which is the ratio of sludge head loss to water head loss. An empirical equation relating R(hl) to pipe velocity and solids concentration, derived from the results of the CFD calculations, is presented. The results are compared with published values of Rhl for solids concentrations of 3 and 6%. A new expression for the Fanning friction factor for wastewater sludge flow is also presented.     

Toxicity assessment of municipal sewage treatment plant effluent by an integrated biomarker response in the liver of crucian carp (Carassius auratus)

In this study, crucian carp (Carassius auratus) was exposed to the increasing concentrations of municipal sewage treatment plant effluent (MSTPE) for 15 days, and the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and acetylcholinesterase (AChE), together with the contents of malondialdehyde (MDA) and glutathione (GSH) in the liver of C. auratus were investigated. Moreover, the integrated biomarker response (IBR) approach was applied to assess the adverse effects of MSTPE in freshwater. The aim of the study was to provide an effective biological indicator for evaluating the toxicity effects and ecological risks of MSTPE in the freshwater environment quantitatively. Results showed that MSTPE could cause oxidative damage to the liver of C. auratus, which reflected through the increasing MDA content over the exposure period. MSTPE also led to the biochemical responses of antioxidant defense in C. auratus liver, such as the enhancement of SOD, CAT, and GPx activities, as well as the inhibition of AChE activity and GSH content. It was found that MDA, SOD, GPx, and GSH could be used as the biomarkers for reflecting the adverse effects of MSTPE in the receiving freshwater on the 12th day of exposure. A significant increase of IBR values was observed as the increasing concentration of MSTPE, and the IBR values presented a significant positive correlation (r?=?0.891, P?<?0.05) with the increasing concentrations of MSTPE, indicating that IBR approach is a promising tool for assessing the toxicity effects of MSTPE in environmental freshwater.

     

红萍净化水产养殖水体的研究

利用红萍(Azolla)对富营养化水产养殖水体进行净化研究。结果表明，红萍能显著增加水体中的DO，增氧幅度随流量在16.88%～70.46%之间变化，随着养殖水体流经的层数增多或者处理的时间延长，红萍对水体的增氧量加大，水中DO最终趋向一个常数值K；同时，红萍对水体中的NH₃-N和TP都有明显的去除效果，NH₃-N去除率随流量在9.86%～38.90%间波动，TP的去除率则随流量的变化在5.80%～38.43%之间波动。可见，红萍是净化水质的良好材料，能有效改善水产养殖水环境。利用红萍净化水体将为解决高密度集约化水产养殖的瓶颈提供新途径，实现水产养殖用水的封闭循环利用。     

燃煤烟气低温SCR脱硝中试研究

低温选择性催化还原(SCR)脱硝是国内外脱硝技术研发的热点,但目前主要集中在实验室小试范围,无法完全反映催化剂在实际烟气中的运行状况。在30 t/h循环流化床燃煤锅炉脱硫除尘装置后建设了2 000~5 000 m3/h的SCR脱硝中试装置,经系统研究发现,中试使用的蜂窝式催化剂对SO2和NO具有很强的吸附能力,且反应温度、喷氨速率和气体空速均会影响催化脱硝效率。为期5 d的连续运行实验结果表明,催化剂的脱硝效率一直稳定在30%~50%,并未发现明显的失活,这证明设计除雾除尘器、较大的混合器、混合器与反应器间较长的管路均有利于缓解催化剂因SO2、H2O和飞灰中的碱性金属导致的失活。     

Effects of temperature on sorption-desorption processes of imidacloprid in soils of Croatian coastal regions

Sorption-desorption behavior of imidacloprid in six soils collected from five coastal regions in Croatia at 20, 30 and 40°C was investigated using batch equilibrium technique. Isothermal data were applied to Freundlich, Langmuir and Temkin equations, and the thermodynamic parameters ΔH°, ΔG°, ΔS° were calculated. The sorption isotherm curves were non-linear and may be classified as L-type, suggesting a relatively high sorption capacity for imidacloprid. Our results showed that the K ^sor _F values decreased for all the tested soils as the temperature increased, indicating that the temperature strongly influences the sorption. Values of ΔG° were negative (?4.65 to ?2.00 kJ/mol) indicating that at all experimental temperatures the interactions of imidacloprid with soils were spontaneous processes. The negative and small ΔH° values (?19.79 to ?8.89 kJ/mol) were in the range of weak forces, such as H-bonds, consistent with interactions and partitioning of the imidacloprid molecules into soil organic matter. The ΔS° values followed the range of ?57.12 to ?14.51 J/molK, suggesting that imidacloprid molecules lose entropy during transition from the solution phase to soil surface. It was found that imidacloprid desorption from soil was concentration and temperature-dependent, i.e. at lower imidacloprid concentrations and temperature, lower desorption percentage occurred. Desorption studies revealed that hysteretic behavior under different temperature treatments existed, and it was more pronounced at 20°C in the soils with higher OC content. The study results emphasize the importance of thermodynamic parameters in controlling soil pesticide mobility in different geographical locations, seasons and greenhouse conditions.     

酚类化合物对硝化颗粒污泥活性抑制的定量结构 活性相关研究

测定了酚类化合物对硝化颗粒污泥活性抑制的logIC₅₀值，以量子化学参数为自变量，应用偏最小二乘法（PLS），建立了酚类化合物对硝化颗粒污泥活性抑制的定量结构活性相关（QSAR）模型。模型所提取的PLS主成分所能解释的因变量总方差的比例Q²_cum为0.820，表明模型具有较好的稳定性和预测能力。模型的结果表明，影响酚类化合物对硝化颗粒污泥活性抑制的主要因素是logkow、CCR和E_homo，酚类化合物对硝化颗粒污泥活性抑制的logIC₅₀随着分子logkow的增大而减小，随着E_homo和CCR的增大而增大。