模拟车用工况下5 kW燃料电池尾气净化系统

模拟了车用工况下燃料电池发动机脉冲式排氢的特点，设计开发了一套质子交换膜燃料电池的尾气净化系统，并以5 kW燃料电池的尾气排放为例，研究其净化效果。研究了电池阳极排放氢气缓冲前后尾气中氢气浓度的变化，以及不同空速条件下氢气的去除效果。结果表明：电堆阳极排放氢气经过缓冲处理后，尾气中氢气浓度趋于平稳，大部分工况下处在2%以下，达到了安全处理的要求；尾气中氢气的去除效果与空速密切相关。对自制的整体式催化剂而言，当空速低于20 000 h^-1时，氢气的去除率能达到约95%，而当空速达到39 270 h^-1时，氢气的去除率仅为10.9%。鉴于这一问题，提出通过采用尾排空气的分流手段调整催化燃烧反应器对空速的要求，以提高尾气中氢气的去除率。     

MBBR处理猪场废水厌氧消化液的研究

采用移动床生物膜反应器(MBBR)处理猪场废水厌氧消化液,考察了水力停留时间(HRT),进水COD和NH3-N浓度对反应器处理效果的影响.结果表明,在温度为20～30℃,填料填充比为50%,进水COD和NH3-N浓度分别为1016 mg/L和496 mg/L条件下,当HRT为12.5 h时,COD和NH3-N去除率可分别达到62%和77%,猪场废水厌氧消化液中可生物降解性有机物基本得到去除,当HRT增至23.8 h时,COD和NH3-N去除率分别为64%和86%,出水COD和NH3-N浓度分别为368 mg/L和70 ms/L,均达到了<畜禽养殖业污染物排放标准>(GB18596-2001)的要求.     

活性炭纤维生物膜帘修复污染源水

采用动力辅助活性炭纤维生物膜帘,模拟研究受污染水源水的原位修复过程,探讨了在不同温度和初始氨氮浓度下生物膜帘对源水修复效果的影响。实验结果表明,中温有利于微生物对有机物和氨氮的降解,低温则有利于微生物除磷。在35℃时CODMn和NH3-N去除效果最好,去除率分别达到90%和94%,15℃时TP去除效果最好,去除率达到54%;在不同氨氮浓度(分别取1.27、1.68和2.54 mg/L)时,生物膜帘对CODMn去除效果都较好,去除率稳定在85%左右,对NH3-N和TP去除效果随初始氨氮浓度的升高而逐渐下降,氨氮去除率由96%下降到92%、TP去除率由40%下降到30%左右。     

以养殖废水为底料的微生物燃料电池产电性能与水质净化效果

以养殖场沼泥为接种物,构建了乙二胺、三氯化铁改性碳毡阳极的单室无膜微生物燃料电池,探讨了2种阳极改性电池的产电规律,考察了其去除养殖废水中COD、氨氮的效果以及臭味的表观性状变化。结果表明,以葡萄糖为底物时,乙二胺、三氯化铁改性阳极微生物燃料电池在启动20 d和22 d后分别达到稳定,输出电压分别为0.514 V和0.527V(外阻为500Ω),对应输出功率密度分别为332 mW/m2和349 mW/m2。逐渐增大废水投加比例至原水时,2个电池的最大功率密度分别为208 mW/m2和158 mW/m2,COD去除率分别为85%和78%,氨氮去除率分别为52%和45%。此外,养殖废水的臭味去除效果明显。因此,构建的2种改性阳极微生物燃料电池可以利用养殖废水产电,同时使水质得到一定程度的净化。     

方解石对水中磷的去除效果研究

以60~100目天然方解石为实验材料,通过对不同浓度磷的去除效果实验和动态实验研究了其对磷的去除性能,并研究不同pH值下方解石对磷的去除效果。对不同pH值下方解石对800 mg/L磷的去除效果研究结果表明,pH对去除效果影响较大,在初始pH值为4.9(平衡pH值为6.4)时去除率最高,对磷的去除率达到31%;对pH范围4.5~4.8内不同浓度的磷的去除效果实验表明,方解石对高浓度的磷去除效果较好,对100 mg/L的磷去除率为20%,对1 600 mg/L的磷去除率达到49%。在酸性条件下,方解石对磷的去除机理为Ca2+与HPO24-的化学沉淀过程。动态实验表明,填充高度为25.4 cm及填充直径为10 cm时,方解石对流速为66.85 mL/min,浓度为100 mg/L磷的去除效果较差,5 min时出水去除率为64%,再生后对磷的去除效果较好,前10 min去除率在90%以上,理论最大去除量提高了53%。     

厌氧池-复合型人工湿地系统污水处理效果的季节变化

利用厌氧池-复合型人工湿地(AT-ICW)系统处理农村生活污水,探讨工艺系统不同季节对污水的处理效果。结果表明,该工艺系统春、夏、秋季对氨氮(NH4+-N)、总磷(TP)表现出稳定且较好的去除效果,去除率分别为92.8%～97.0%和56.4%～65.9%,冬季去除率相对较差,平均去除率分别为67.1%和42.5%。NO3--N的去除效果差,四季均出现积累,累积率达到71.5%～342.9%。系统春、夏季对总氮(TN)去除效果较好,去除率为57.3%～68.9%,秋、冬季去除效果相对较差,为24.5%～35.8%。系统夏季COD去除效果好,平均去除率达到78.3%,冬、春季去除效果较差,为37.8%～43.5%。各项污水排放指标均达到城镇污水处理厂污染物排放一级A类标准。AT-ICW系统不仅处理效果好,而且运行费用低,适用于农村分散型生活污水处理。     

酸性洗涤塔-生物滤塔-生物曝气池组合工艺处理恶臭气体NH3和H2S

采用酸性洗涤塔、生物滤塔和生物曝气池的组合工艺处理NH3、H2S恶臭混合气体,研究表明,该组合工艺对NH3和H2S有很好的去除效果,在进气流量为35 L/min,喷淋量45 L/h时,NH3进气浓度50.15~525.4 mg/m3,H2S进气浓度10.23~110.36 mg/m3时,NH3单一进气去除率稳定在99%以上,H2S单一进气去除率90%以上。混合进气后,NH3去除率几乎为100%,H2S的去除率提高至98%以上。在一定的浓度范围内,NH3和H2S之间的相互作用对两者的去除效果没有明显的影响,而且起到了相互促进降解的作用。同时,进气流量和填料层高度都会影响NH3、H2S的去除率。系统对进气容积负荷变化的缓冲能力强,在偶尔超负荷条件下运行并不能使系统崩溃,并且微生物对高负荷逐渐表现出适应性。大部分溶于水的氨由生物曝气池去除,去除率达到96.9%。     

铝铁电极联用电絮凝法处理Cu-EDTA络合废水

采用电絮凝法处理Cu-EDTA模拟废水,研究电极组合方式、初始pH值和氯化钠浓度3个因素对化学需氧量(COD)和Cu去除效果的影响。实验研究发现,当电极组合方式为2个铝阳极和2个铁阴极,起始pH值为3,氯化钠浓度为0.5 g/L,换极周期为40 min,反应时间为80 min时,COD去除率达到78.7%,Cu离子去除率达到99.9%。通过实验研究确定EDTA的去除机制主要是:酸性条件下的次氯酸氧化作用,碱性条件下的氢氧化物絮凝沉淀作用及单核态铝/铁与多核态铝/铁电荷中和作用,Cu的去除机制主要是氢氧化物的絮凝沉淀作用和铁电极的电沉积作用。     

臭氧-BAF组合工艺处理电镀RO浓水

电镀废水反渗透(RO)浓水具有盐度高、难降解有机物浓度高、含重金属等特点,是电镀废水处理工艺提标改造的难点。采用臭氧-曝气生物滤池(BAF)组合工艺,对电镀废水反渗透(RO)浓水中有机物进行处理,使出水COD浓度达到《电镀污染物排放标准》中标准。考察了废水初始p H、臭氧浓度和反应时间等因素对臭氧氧化效果的影响,以及水力停留时间(HRT)和气水比对BAF单元COD去除效果的影响。经优化后的系统运行工况为:臭氧氧化单元中废水初始p H值为10.0,臭氧浓度为31.96 mg·L~(-1),反应时间为40 min;BAF的HRT为3 h,气水比为5∶1。在最佳工况下,当进水COD为180~240 mg·L~(-1)时,经组合工艺处理后COD去除率达78.6%,平均出水COD浓度为47 mg·L~(-1),达到了标准的要求。     

多针-板脉冲放电处理模拟尾气中的NO_x

机动车尾气中NO_x受到人们普遍关注。采用多针-板放电反应器,研究NO_x浓度变化随电气、气体等参数的变化规律,为脉冲放电去除NO_x提供一定理论支撑。结果表明:在一定条件下提高脉冲电压有利于NO转化;脉冲重复频率增大可提升NO_x去除率,脉冲重复频率达到一定值时NO_x去除率增幅不明显;流量增大利于NO转化,不利于NO_x去除;随氧浓度的升高NO转化率呈现先降低后升高,NO_x去除率逐渐降低。当氧浓度低于5%时,NO_x主要是通过NO还原成N_2;氧浓度高于5%时,NO主要通过氧化转化为NO_2。     

纳米催化技术用于空气净化

纳米催化剂作为新一代高效环保催化剂 ,在大气污染治理 ,尤其是在室内空气净化中有着广阔的应用前景。评述了纳米催化技术在光催化空气净化、汽车尾气净化、化石燃料脱硫和降低温室效应等空气净化领域的研究进展 ,并对应用纳米催化技术净化空气的关键科学问题进行了分析和展望     

CeO2-CoO／ACF低温SCR烟气脱氮性能的研究

活性炭纤维（ACF）经硝酸处理后采用浸渍法制备了CeO2-CoO／ACF复合催化剂，测试了其在以氨气为还原剂的低温SCR过程中的催化活性，同时研究了金属氧化物浸渍顺序及负载量、催化剂煅烧温度、空速比（SV）、NH，／NO（摩尔比）、O2含量等因素对NO转化效率的影响。研究发现，负载量为10％的CeO2-CoO／ACF复合催化剂经煅烧后在120—240℃时具有很高的催化活性，并且在N0初始浓度为1000mg／m3、空速比（SV）为6000h～、NH3／NO为1．05、O：体积分数在3．0％时具有较高的NO转化效率。     

活性炭纤维在机动车尾气净化中的研究与应用展望

机动车尾气净化控制的一个难点在于冷启动阶段，此时由于温度较低，催化剂尚未完全起作用，导致排出的污染物浓度较高。阐述了活性炭纤维的基本特性，特别是其低温吸附与催化性能对NO和CO的转化作用，讨论了活性炭纤维作为机动车尾气净化材料所需的改性及方法，并展望了其应用前景。     

Air pollution reduction via use of green energy sources for electricity and hydrogen production

The implementation of renewable wind and solar energy sources instead of fossil fuels to produce such energy carriers as electricity and hydrogen facilitates reductions in air pollution emissions. Unlike from traditional fossil fuel technologies, air pollution emissions from renewable technologies are associated mainly with the construction of facilities. With present costs of wind and solar electricity, it is shown that, when electricity from renewable sources replaces electricity from natural gas, the cost of air pollution emission abatement is more than ten times less than the cost if hydrogen from renewable sources replaces hydrogen produced from natural gas. When renewable-based hydrogen is used instead of gasoline in a fuel cell vehicle, the cost of air pollution emissions reduction approaches the same value as for renewable-based electricity only if the fuel cell vehicle efficiency exceeds significantly (i.e., by about two times) that of an internal combustion vehicle. The results provide the basis for a useful approach to an optimal strategy for air pollution mitigation.     

活性炭纤维在机动车尾气净化中的研究与应用展望

机动车尾气净化控制的一个难点在于冷启动阶段,此时由于温度较低,催化剂尚未完全起作用,导致排出的污染物浓度较高。阐述了活性炭纤维的基本特性,特别是其低温吸附与催化性能对NO和CO的转化作用,讨论了活性炭纤维作为机动车尾气净化材料所需的改性及方法,并展望了其应用前景。     

某厂金属铜管加工废气处理方法的研究

我国对于大气污染物的排放给予了高度的重视,规定生产中的污染物必须达标排放。对某厂酸洗车间产生的以酸雾和氮氧化物为主的废气采用高效局部排气罩加以集中收集,设计了净化吸收系统,使经过处理的废气达到“大气污染物综合排放标准”中的二级排放要求,并在设计中充分考虑了系统的节能,收到了良好的环保效果。     

某厂金属铜管加工废气处理方法的研究

我国对于大气污染物的排放给予了高度的重视，规定生产中的污染物必须达标排放。对某厂酸洗车间产生的以酸雾和氮氧化物为主的废气采用高效局部排气罩加以集中收集，设计了净化吸收系统，使经过处理的废气达到“大气污染物综合排放标准”中的二级排放要求，并在设计中充分考虑了系统的节能，收到了良好的环保效果。     

Effects of Fuel Type,Driving Cycle,and Emission Status on In-Use Vehicle Exhaust Reactivity

ABSTRACT

The introduction of reformulated gasolines significantly reduced exhaust hydrocarbon (HC) mass emissions, but few data are available concerning how these new fuels affect exhaust reactivity. Similarly, while it is well established that high-emitting vehicles contribute a significant portion of total mobile source HC mass emissions, it is also important to evaluate the exhaust reactivity from these vehicles. The objective of this study was to evaluate the relative influence on in-use vehicle exhaust reactivity of three critical factors: fuel, driving cycle, and vehicle emission status. Nineteen in-use vehicles were tested with seven randomly assigned fuel types and two driving cycles: the Federal Test Procedure (FTP) and the Unified Cycle (UC). Total exhaust reactivity was not statistically different between the FTP and UC cycles but was significantly affected by fuel type. On average, the exhaust reactivity for California Phase 2 fuel was the lowest (16 % below the highest fuel type) among the seven fuels tested for cold start emissions. The average exhaust reactivity for high-emitting vehicles was significantly higher for hot stabilized (11%) and hot start (15%) emissions than for low-emitting vehicles. The exhaust reactivities for the FTP and UC cycles for light-end HCs and carbonyls were significantly different for the hot stabilized mode. There was a significant fuel effect on the mean specific reactivity (SR) for the mid-range HCs, but not for light-end HCs or carbonyls, while vehicle emission status affected the mean SR for all three HC compound classes.     

In Situ Measurement of Hydrochloric Acid in Rocket Exhaust Clouds Using a Remotely Piloted Aircraft

Abstract

An instrumentation system employing an RPV (remotely piloted vehicle) platform was developed for temporally and spatially resolved air pollution measurements, and was used to measure the evolution of gas-phase HC1 in exhaust clouds from a solid rocket motor firing and fuel pit burns. A thermistor and a sensitive (ppmv-level), rapid-response (<0.1 sec) infrared absorption sensor for HC1 were mounted in a flow channel in the RPV, permitting concentration and temperature measurements to be made in the cloud on a several-meter scale. The RPV system was flown in a series of field tests at Thiokol Corporation’s Elkton, MD division to evaluate the HC1 content of the exhaust products of a new Mg-based fuel formulation. Measurements were made in the clouds from Al-based and Mg-based solid fuel pit burns and a Mg-fueled motor firing over periods of several minutes. Elevated temperatures and HC1 concentrations were found to be temporally correlated with video images of the particulate cloud. Cl originating from the ammonium perchlorate oxidizer appeared in the exhaust as HC1 in each of the tests. Both the macroscopic and local cloud parameters indicate that the Mg-based fuel may provide some reduction in HC1 concentration compared to the standard Al-based fuel.