湿型砂铸造中危险性空气污染物的测试与分析

用分析裂解技术模拟湿型砂铸造过程中湿型砂与煤粉的热解过程,并采用GC-FID/MS等对分析裂解产生的危险性空气污染物(hazardous air pollutant,HAP)进行了分析.研究表明,湿型砂铸造过程中产生的HAP主要是由于湿型砂中的煤粉热解产生的,其主要成分为苯、甲苯、二甲苯、苯酚和萘等.慢速热解时,HAP主要产生在350～700℃.快速热解时,HAP的产率明显高于慢速热解时的产率.通过与实际铸造过程中产生的HAP对比发现,分析裂解与实际铸造过程中产生的HAP成分十分相似.因此,可以采用分析裂解实验获取铸造过程的HAP清单.与传统的采用实际铸造获取HAP清单的方法相比,分析裂解实验可以大幅度降低获取铸造过程HAP清单的检测成本和检测时间.     

MEIC排放清单在空气质量模式中的应用研究

本文主要研究了清华大学MEIC 2012基准年0.25°×0.25°排放清单应用于WRF-CHEM模式所需的主要处理技术,包括:单位面积污染物排放质量(或物质的量)浓度的计算,经纬度格点浓度到中尺度格点浓度的转换,使用模式地表类型数据对排放清单进行细化处理,各部门小时排放数据的确定以及PM_(2.5)组成成分比例的区域分配等.通过重污染个例的预报和模拟试验分析了清单处理技术的应用效果,结果表明:模式能较好地反映出污染物局地累积和水平输送的变化趋势,但高污染中心的浓度预报值要低于实际观测值,这与气象场的预报偏差有较大关系.清单细化处理技术可以改变模式格点上污染物的模拟浓度,但在不同气象条件下,改变量有所不同,静稳天气下,城市及其周边地区的改变量较大.     

铸造废砂的环境毒性研究

采用毒性特性浸出程序、顶空气相色谱技术检测了5种铸造废砂中的重金属与有机污染物,采用发光细菌毒性检测技术和土壤酶活性实验研究了废砂的生物效应.结果表明,由于浇注金属与造型材料的不同,5种铸造废砂中的金属与有机污染物成分和浓度均有较大差异.其中,铸铁与铸钢废砂浸出液中的铁离子,铸铝废砂中的As离子超出了《地表水环境标准》规定的最大允许检出浓度.5种废砂中的有机污染物种类十分复杂,对发光细菌表现出不同程度的抑菌活性,发光强度的抑制率在30%～95%之间.此外,土壤酶活性实验结果表明,废砂中的金属污染物可能会抑制土壤中微生物的活性,而有机物则对土壤微生物的活性有一定的促进作用.因此,铸造废砂的随意排放将会对环境造成较严重的威胁.     

废旧有机玻璃再生利用行业挥发性有机物(VOCs)排放特征研究

以浙江省湖州某镇的废旧有机玻璃裂解再生行业污染整治为例,通过选取4家具有代表性的废旧有机玻璃裂解再生企业,对其整治后排放的工艺废气和厂界空气中特征污染物浓度进行监测,分析其与国内外现有标准限值的符合性,并评估其厂界特征污染物产生的人体健康风险,为建立该行业地方污染物排放标准提供依据.结果表明,废旧有机玻璃再生行业排放废气成分主要为甲醇和甲基丙烯酸甲酯,且后者存在超标的情况;虽然厂界空气中的臭气浓度基本超过了现行的国家标准,但其特征污染物基本不会对人体健康产生较大的危害.另外,根据现有企业的实际情况,以较先进治理技术为依据,并参考国内外相关标准的基础上,建议该行业地方标准中甲醇、甲基丙烯酸甲酯及臭气浓度指标现有/新建(无组织)限值分别为45/30(0.5)mg·m-3、30/25(0.5)mg·m-3及1 000/800(20).     

西欧制浆与造纸工业中的清洁工艺

为了控制日益严重的工业污染,发达国家早在五十年代即已发展了大量的“排放口”治理技术。排放口治理技术主要是在生产过程终端对所产生的污染进行被动的治理。清洁技术或称低废、无废技术是西欧七十年代初发展起来的。清洁技术强调“治本”,即通过改革生产工艺,采用低毒或无毒原材料,提高原材料和能源利用率或进行综合利用,建立更有效的工艺装置,采用再循环技术等,以便将污染尽可能减少或消灭在生产过程中。因而与排放口治理技术相比,采用清洁技术不但可显著降低生产过程终     

行业全过程水特征污染物和优控污染物清单筛选技术研究及其在常州市纺织染整业的应用

特征污染物和优控污染物筛选技术主要针对流域和水体环境,缺乏从行业全过程角度对问题进行研究,行业层面的筛选技术仍不成熟.基于清洁生产全过程管控理念,通过资料收集、现场考察和水样检测分析,对行业全过程污染物排放特征进行分析,形成行业特征污染物清单调查和筛选技术;在将特征污染物与已有清单比对的基础上,对其暴露性、持久性、毒性进行赋分排序,采用综合评分法形成行业优控污染物清单筛选技术,并将该筛选技术方法在常州市纺织染整行业开展应用.结果表明:①通过全流程考察,结合气相色谱-质谱联用仪90%匹配度下的水样检测结果,最终得到纺织染整行业特征污染物清单中共含199种物质,其中以苯系物、脂类、烷烃和醇类为主(占比为65.3%).②纺织染整行业优控污染物清单中共含39种物质,包括13种苯系物、3种卤代烃、5种醇类、5种脂类、1种醛类、2种酮类、3种醚类、1种呋喃类、6种重金属.研究显示,运用行业特征污染物和优控污染物清单调查和筛选技术,可较为科学和有效地得到常州市纺织染整行业特征污染物清单和优控污染物清单.      

ADMS模型测算鞍山市空气中SO2环境容量

利用ADMS城市大气扩散模型测算鞍山市空气中SO2环境容量.通过建立鞍山市空气污染物排放清单、建立空气质量扩散模型、模拟不同污染物排放量的环境质量状况,确定鞍山市大气SO2环境容量.测算结果鞍山市大气SO2环境容量为58063t.     

实施《清洁空气研究计划》推动大气污染物排放清单支撑体系建设

我国大气污染形势严峻,文章指出大气污染物排放清单是空气质量管理的基础,污染源“底数不清”严重制约我国大气污染防治工作,亟需尽快建立大气污染物排放清单.通过分析现阶段我国科学构建大气污染物排放清单的指导原则,以及大气污染物排放清单支撑体系建设进展,提出应从重视技术指南的实践与应用、加强清单编制科学研究及能力建设三方面完善大气污染物排放清单体系建设.     

京津冀城市群大气污染传输规律研究——两组排放清单的比较分析

利用WRF/CALPUFF耦合模型,在同样重污染气象条件下,选择了当下模拟应用最广的两组排放清单对4种主要污染物（NO_x,SO₂,PM_2.5和PM₁₀）进行京津冀城市间区域传输贡献比较分析.其中一组排放清单来自政府的环境统计（以下称：环统排放清单）,另一组排放清单是来自中国多尺度排放清单（以下称：MEIC排放清单）.污染物的浓度空间分布表明,两种排放清单下污染物浓度均呈现北部以唐山中心,南部以石家庄-邯郸为中心的分布特征,均是由两个浓度最高的中心向外逐渐降低.但是环统排放清单下模拟的污染物浓度高值区范围更大,更接近实际监测数据.基于不同的清单输入,一些城市的传输角色存在一些差异.例如,对于4种污染物,两种排放清单模拟出的沧州与周边城市的净传输方向完全相反,在MEIC排放清单中,沧州以向外净传输为主,即为源;而在环统排放清单中,沧州则变成了净输入城市,即为汇.这些结论将影响大气联防联控中各城市源汇责任的认定,在实际环境管理中应注重多源数据的选择、验证和比较.     

美国环境标准制定中的利益衡量——以美国《清洁空气法》为例

本文以美国《清洁空气法》为例,结合《清洁空气法》的相关规定、美国法院的相关判决以及学者的理论探讨,采用规范分析和案例分析等方法,揭示了美国大气环境质量标准和大气污染物排放标准在制定过程中的利益衡量。通过分析解读美国《清洁空气法》在环境标准制定中的利益衡量实例,提出我国环境质量标准的制定应当以保护人体健康为主要目标,并考虑我国现实的技术水平和社会经济承受能力;污染物排放标准的制定应基于环境质量标准,主要考虑我国现实的技术水平和社会经济承受能力;应进一步制定我国环境标准制定过程中利益衡量的具体准则。     

杂质对废塑料裂解产物及污染物排放的影响

从垃圾中分选出的废塑料混有大量杂质,杂质对现有废塑料裂解工艺有直接的影响.针对这一问题,对混有厨余、纸、织物和渣土等杂质的废塑料裂解产物和污染物排放进行了研究.同时检测和分析了厨余、纸、织物和沙土等常见杂质所含N、Cl、S元素向裂解油、裂解气中的迁移规律.研究表明,厨余的混入将对裂解油的产物产生严重不利影响,如热值降低至27 MJ/kg,油品的含水率高达25%以及多环芳烃含量大大提高,因而应在分选过程中除去.厨余、织物和纸张等杂质的混入导致裂解气体中污染物浓度的显著上升.渣土的混入对气体产物有有利影响,对油品无明显不利影响.     

Bio-char Sequestration in Terrestrial Ecosystems – A Review

The application of bio-char (charcoal or biomass-derived black carbon (C)) to soil is proposed as a novel approach to establish a significant, long-term, sink for atmospheric carbon dioxide in terrestrial ecosystems. Apart from positive effects in both reducing emissions and increasing the sequestration of greenhouse gases, the production of bio-char and its application to soil will deliver immediate benefits through improved soil fertility and increased crop production. Conversion of biomass C to bio-char C leads to sequestration of about 50% of the initial C compared to the low amounts retained after burning (3%) and biological decomposition (< 10–20% after 5–10 years), therefore yielding more stable soil C than burning or direct land application of biomass. This efficiency of C conversion of biomass to bio-char is highly dependent on the type of feedstock, but is not significantly affected by the pyrolysis temperature (within 350–500 ^∘C common for pyrolysis). Existing slash-and-burn systems cause significant degradation of soil and release of greenhouse gases and opportunies may exist to enhance this system by conversion to slash-and-char systems. Our global analysis revealed that up to 12% of the total anthropogenic C emissions by land use change (0.21 Pg C) can be off-set annually in soil, if slash-and-burn is replaced by slash-and-char. Agricultural and forestry wastes such as forest residues, mill residues, field crop residues, or urban wastes add a conservatively estimated 0.16 Pg C yr⁻¹. Biofuel production using modern biomass can produce a bio-char by-product through pyrolysis which results in 30.6 kg C sequestration for each GJ of energy produced. Using published projections of the use of renewable fuels in the year 2100, bio-char sequestration could amount to 5.5–9.5 Pg C yr⁻¹ if this demand for energy was met through pyrolysis, which would exceed current emissions from fossil fuels (5.4 Pg C yr⁻¹). Bio-char soil management systems can deliver tradable C emissions reduction, and C sequestered is easily accountable, and verifiable.     

Emission of intermediate volatility organic compounds from a ship main engine burning heavy fuel oil

Intermediate volatility organic compounds (IVOCs) are crucial precursors of secondary organic aerosol (SOA). In this study, gaseous IVOCs emitted from a ship main engine burning heavy fuel oil (HFO) were investigated on a test bench, which could simulate the real-world operations and emissions of ocean-going ships. The chemical compositions, emission factors (EFs) and volatility distributions of IVOC emissions were investigated. The results showed that the main engine burning HFO emitted a large amount of IVOCs, with average IVOC EFs of 20.2–201?mg/kg-fuel. The IVOCs were mainly comprised of unspeciated compounds. The chemical compositions of exhaust IVOCs were different from that of HFO fuel, especially for polycyclic aromatic compounds and alkylcyclohexanes. The volatility distributions of IVOCs were also different between HFO exhausts and HFO fuel. The distinctions in IVOC emission characteristics between HFO exhausts and HFO fuel should be considered when assessing the IVOC emission and related SOA formation potentials from ocean-going ships burning HFO, especially when using fuel-surrogate models.     

生物质再燃脱硝及其同相还原反应特性

利用固定床反应器研究了稻壳、木屑和玉米秸3种生物质在不同工况〔再燃温度、φ(O₂)〕下的再燃脱硝效率,同时考察了再燃区出口处CO、H₂、碳氢类物质(主要是CH₄)、HCN和NH₃的体积分数随工况的变化规律. 结果表明:生物质类型对再燃脱硝效率有很大影响,木屑再燃脱硝效率最大值达57.0%±2.1%,高于稻壳(50.0%±1.5%)和玉米秸(51.0%±1.1%). 在再燃过程中,生物质产生的热解气能够增强还原性气氛,从而提高再燃脱硝效率,当烟气中φ(O₂)为0%～1%时,再燃脱硝效率较高. 在还原性气氛(800～1 200 ℃)下,3种生物质再燃脱硝效率差异主要来自生物质不同热解气与NO的同相反应. 其中,碳氢类物质对NO的还原起到了关键作用,而CO和H₂所起作用并不大,φ(HCN)与φ(NH₃)之和反映了气相中NO向N₂的转化趋势. 因此,深入了解生物质热解气对其再燃脱硝效率的影响机制有益于燃料再燃脱硝效率的提高.      

Optimization of gasoline hydrocarbon compositions for reducing exhaust emissions

Effects of hydrocarbon compositions on raw exhaust emissions and combustion processes were studied on an engine test bench. The optimization of gasoline hydrocarbon composition was discussed. As olefins content increased from 10.0% to 25.0% in volume, the combustion duration was shortened by about 2 degree crank angle ( CA), and the engine-out THC emission was reduced by about 15%. On the other hand, as aromatics content changed from 35.0% to 45.0%, the engine-out NOx emissions increased by 4%. An increment in olefins content resulted in a slight increase in engine-out CO emission, while the aromatics content had little e ect on engine-out total hydrocarbon (THC) and CO emissions. Over the new European driving cycle (NEDC), the THC, NOx and CO emissions of fuel with 25.0% olefins and 35.0% aromatics were about 45%, 21% and 19% lower than those of fuel with 10.0% olefins and 40.0% aromatics, respectively. The optimized gasoline compositions for new engines and new vehicles have low aromatics and high olefins contents.     

Identification of main influencing factors of life cycle CO2 emissions from the integrated steelworks using sensitivity analysis

The amount of CO₂ emissions from steelworks accounts for a great share of the total CO₂ emissions from industry in China. Thus, reducing CO₂ emissions from steelworks is urgent for China's environmental protection and sustainable development. This study aims at identifying factors that influence CO₂ emissions from steelworks and proposing measures to reduce CO₂ emissions. The life cycle inventory (LCI) of iron and steel products implies the relationship between the CO₂ emissions of the steelworks and the input variables of the LCI. The Tornado Chart Tool is utilized to calculate the variation of CO₂ emissions caused by the change of each input variables of LCI. Then, mean sensitivity of each input variable is calculated and the ranking criterion developed is used to identify the main factors influencing the integrated steelworks. Subsequently, measures for reducing CO₂ emissions are proposed. The results indicate that the very important influencing factors of CO₂ emissions in steelworks are the CO₂ emission factor of Blast Furnace Gas (BFG), liquid steel unit consumption of continuous casting, continuous casting slab unit consumption of hot rolling and hot metal ratio of steel making. Consequently, many efficient measures for reducing CO₂ emissions have been proposed, such as removing CO₂ contained in BFG, decreasing the hot metal ratio of Basic Oxygen Furnace (BOF), recycling BFG, optimizing the products' structure, etc.     

重型柴油公交车实际道路颗粒物排放的理化特征

为研究重型柴油公交车实际道路颗粒物排放的理化特征,采用车载排放测试方法,选取了2辆国Ⅲ和4辆国Ⅳ柴油公交车,对气态污染物和颗粒物排放因子、粒径分布及颗粒物中的组分(包括碳组分、离子、元素和有机组分)排放特征进行了实测分析.结果表明:测试车辆的颗粒数量主要集中在100 nm以下粒径段,颗粒质量排放总体呈倒U型分布,粒径峰值位于300 nm左右.OC和EC分别占尾气颗粒物总质量的36.10%±8.94%和27.97%±10.00%,离子和元素组分分别占7.75%±1.01%和22.71%±3.09%.柴油质量对柴油车尾气颗粒物成分具有较大影响,燃用国Ⅲ柴油的车辆尾气中富含S、Ca、Mg、Na等元素组分,其主要来自燃油中的硫分和杂质.在可检出的弱极性可溶有机物中,正构烷烃和脂肪酸的含量较为丰富,分别占颗粒物总质量的1.95%和5.13%,此外还有一定量的藿烷和PAHs(多环芳烃).其中,正构烷烃组分主要分布于C19～C29,正构烷酸主要集中在C12、C14、C16和C18等偶数碳组分.国Ⅲ和国Ⅳ柴油公交车的PAHs排放因子分别为198.2、62.5 μg/km,以3环和4环PAHs为主,菲、荧蒽、芘、惹烯、苯并荧蒽、、苯并[123-cd]芘和苯并苝是较为主要的PAHs组分.需要指出的是,由于采用定比例稀释方法,颗粒物中组分的测试结果可能与其实际排放存在一定偏差.      

我国城市生活垃圾填埋处理CH4排放关键因子

CH₄是大气中主要的温室气体之一,研究我国城市生活垃圾填埋处理CH₄排放关键因子对于准确估算CH₄排放量具有重要意义. 在综合分析我国城市生活垃圾填埋处理场在不同历史发展阶段的处理技术类型、管理方式、垃圾成分和理化特性的基础上,结合北京阿苏卫垃圾填埋场对不同深度(至填埋层下18 m)钻井提取的12组垃圾样品数据,借鉴《2006年IPCC国家温室气体清单指南》推荐的CH₄排放关键因子,确定了MCF(CH₄修正因子)、DOC(可降解有机碳质量分数,下同)、t_1/2(半衰期)和k(CH₄产生率). 结果表明:MCF在不同历史阶段表现出鲜明的时间特征,1978年前、1979—1990年、1991—2000年、2001—2005年和2006—2011年5个阶段的MCF分别为0.40、0.60、0.75、0.92和0.96;我国南、北方城市生活垃圾DOC随时间变化均呈增加趋势,1959—1990年、1991—2000年和2001—2011年3个阶段的DOC分别为9.34%、15.22%和15.05%;我国城市生活垃圾t_1/2为2.30 a,k为0.30 a-1.      

Observation-based sources evolution of non-methane hydrocarbons (NMHCs) in a megacity of China

Both concentrations and emissions of many air pollutants have been decreasing due to implement of control measures in China, in contrast to the fact that an increase in emissions of non-methane hydrocarbons (NMHCs) has been reported. This study employed seven years continuous NMHCs measurements and the related activities data of Shanghai, a megacity in China, to explore evolution of emissions and effectiveness of air pollution control measures. The mixing ratio of NMHCs showed no statistical interannual changes, of which their compositions exhibited marked changes. This resulted in a decreasing trend of ozone formation potential by 3.8%/year (p < 0.05, the same below), which should be beneficial to ozone pollution mitigation as its production in Shanghai is in the NMHCs-limited regime. Observed alkanes, aromatics and acetylene changed by +3.7%/year, -5.9%/year and -7.4%/year, respectively, and alkenes showed no apparent trend. NMHCs sources were apportioned by a positive matrix factorization model. Accordingly, vehicular emissions (-5.9%/year) and petrochemical industry emissions (-7.1%/year) decreased significantly, but the decrease slowed down; significant reduction in solvent usage (-9.0%/year) appeared after 2010; however, emissions of natural gas (+12.6%/year) and fuel evaporation (with an increasing fraction) became more important. The inconsistency between observations and inventories was found in interannual trend and speciation as well as source contributions, emphasizing the need for further validation in NMHCs emission inventory. Our study confirms the effectiveness of measures targeting mobile and centralized emissions from industrial sources and reveals a need focusing on fugitive emissions, which provided new insights into future air policies in polluted region.