首钢烧结厂PM_(10)治理技术与经济分析

通过对首钢烧结厂的污染结点、污染物特性、污染物控制技术措施和技术规范进行分析,提出了烧结厂PM10控制方案,对烧结厂采用高效除尘设备的PM10削减量及改造费用进行了估算,确定了烧结厂PM10治理技术方案排序,为钢铁企业烧结厂治理颗粒污染物的同时选择最为经济实用的除尘器类型提供理论依据.     

首钢烧结厂PM10治理技术与经济分析

通过对首钢烧结厂的污染结点、污染物特性、污染物控制技术措施和技术规范进行分析，提出了烧结厂PM₁₀控制方案，对烧结厂采用高效除尘设备的PM₁₀削减量及改造费用进行了估算，确定了烧结厂PM₁₀治理技术方案排序，为钢铁企业烧结厂治理颗粒污染物的同时选择最为经济实用的除尘器类型提供理论依据。     

丽水市大气污染的时空分布特征及与气象要素的相关分析

利用2007-2010年丽水市逐日大气污染物浓度数据和地面气象观测资料,对PM10、SO2、NO23种大气污染物浓度进行了时空分布特征研究,进而探讨了气象要素对大气污染的影响.结果表明:2007-2010年,丽水市主要的3种大气污染物的负荷为PM10＞ NO2 ＞SO2,影响大气环境质量的污染物以PM10为主；总体来说,NO2的月均浓度基本达到《环境空气质量标准》(GB3095-1996)-级标准,冬半年(9-12月、1-2月)SO2的月均浓度仅达到二级标准,而夏半年(3-8月)月均浓度基本达到一级标准,PM10的月均浓度都达到二级标准(0.10 mg/m3)；在空间分布上,PM10、NO2的年均浓度都表现出东向西逐渐减少的特征,而SO2年均浓度主要体现为南向北递增的特征,3种大气污染物在空间上都表现为在东部缙云、青田等地的污染相对严重,而在西面的遂昌、龙泉等地的污染程度较轻;各种气象要素对大气污染的影响中,除了气压与3种大气污染物的浓度呈极显著正相关外,其他气象要素都表现为负相关,只是影响程度有所差异.气象要素对大气污染的影响不是单一作用的,而是通过多种气象要素相互配合、相互作用、综合反应来产生作用的.     

和田绿洲沙尘暴强度及其影响因子分析——以墨玉县为例

以和田绿洲西北部的墨玉县为研究区域,对该地区2016—2018年发生的沙尘暴天气资料以及气象因子(气温、风速、湿度、气压、水汽压、日照时数)和大气污染物(PM2.5、PM10、SO2、NO2、CO、O3)进行分析。结果表明,墨玉县沙尘暴天气主要发生在春夏季(3—8月),平均占全年发生频率的77.12%。墨玉县沙尘暴强度主要由气象因子决定,特别是气温、风速、日照时数和湿度。沙尘暴强度与大气颗粒物(PM10和PM2.5)存在着明显的间接关系,主要因为两者均受风速影响较大,沙尘暴强度越大,大气中PM10和PM2.5浓度越高。沙尘暴强度与SO2、NO2、CO、O3等大气污染物的关系非常微弱,但O3与沙尘暴的形成季节比较一致。     

污染物排放削减潜力评估方法——以中小型钢铁企业为例

根据中国中小型钢铁企业污染物排放情况,确立了污染物排放削减潜力评估方法。采用污染物排放削减潜力的数学模型,计算当前生产水平下实施清洁生产和末端治理后对SO2产生量和烟粉尘排放量的削减率,并预测中长期实施清洁生产和末端治理后,污染物产生量和排放量的削减潜力。结果表明,通过采取清洁生产措施和末端治理技术,中小型钢铁企业2020年在4种不同模式下,SO2产生量削减率分别为61.8%、66.4%、73.3%、84.7%;烟粉尘排放量削减率分别为37.9%、44.1%、53.4%、68.9%。通过污染物排放削减潜力的初步研究,不仅从宏观层次上说明了实施清洁生产和末端治理技术的积极意义,而且计算出不同经济发展模式下污染物产生量和排放量的削减量,为行业或区域污染物总量的指标分配和总量控制方案的制订提供了参考依据。     

冬季沈阳市典型源排放PM_(10)浓度分布模拟分析

选取沈阳市7个典型的大气污染源2006年12月~2007年2月的PM10排放浓度资料,利用CALPUFF对PM10浓度月平均分布做模拟分析。模拟结果分析表明:冬季月平均PM10浓度分布的范围与风场、地形有直接的关系。地势平坦、风速大时,污染物扩散范围大,污染物浓度小;地势不平、风速小时,污染物扩散范围小,污染物浓度大。1月份是沈阳市冬季月平均大气污染最严重的月份,污染物分布主要集中在市区的北部、东部和南部地区,东部地区大气污染最为严重。     

冬季沈阳市典型源排放PM10浓度分布模拟分析

选取沈阳市7个典型的大气污染源2006年12月～2007年2月的PM10排放浓度资料，利用CALPUFF对PM10浓度月平均分布做模拟分析。模拟结果分析表明：冬季月平均PM10浓度分布的范围与风场、地形有直接的关系。地势平坦、风速大时，污染物扩散范围大，污染物浓度小；地势不平、风速小时，污染物扩散范围小，污染物浓度大。1月份是沈阳市冬季月平均大气污染最严重的月份，污染物分布主要集中在市区的北部、东部和南部地区，东部地区大气污染最为严重。     

杭州城市大气消光系数和能见度的影响因子研究

为了解杭州市能见度下降与大气污染之间的关系，在2001年5月至2002年5月对不同粒径的颗粒物（PM10、PM2.5）的质量浓度进行了观测，结合晴天天气条件下的大气能见度，推算污染物和水汽分子对大气的消光散射，发现细微颗粒物的散射消光特性对杭州市能见度下降起主要作用，并得到能见度与细微颗粒物浓度比值（PM2．5／PM10）的关系；分析了大气能见度和消光系数与PM2．5／PM10和相对湿度的相关系数。     

杭州城市可吸入颗粒物污染与气象条件关系的分级评价和BP神经网络评估

为了解杭州城市环境空气质量与气象条件之间的关系,利用杭州市区2003-2007年的可吸入颗粒物(PM10)浓度数据和气象资料,通过分级评价的方法和基于BP神经网络的污染物浓度评估模型,得到PM10浓度与气象条件的对应关系.结果表明,随着日降水量的增大,PM10浓度减小;风速与PM10浓度呈明显的负相关,随着风速的增大,PM10浓度明显减小;气象因素与PM10浓度之间呈非线性关系,大气能见度对PM10和相对湿度的变化极为敏感.随着PM10浓度的增大,大气能见度迅速降低,相对湿度越高,大气能见度则越低;近几年杭州市气象条件不利于大气污染物的扩散和清洗,是杭州城市环境空气质量上升缓慢的主要原因之一.     

燃煤工业锅炉大气污染物控制方案研究

基于中国燃煤工业锅炉大气污染物排放及治理现状,并结合国家相关产业政策和国内外技术发展趋势,以2008年为基准年,分析测算了2015、2020年燃煤工业锅炉大气污染物排放量,提出了适合中国国情的燃煤工业锅炉大气污染物控制技术路线.依据研究的控制方案,2015年,烟尘、二氧化硫及氮氧化物排放量分别为507万、458万、230万t；2020年,烟尘、二氧化硫及氮氧化物排放量分别为491万、423万、269万t.与2008年相比,大气污染物排放量变化不大,基本上做到了增容不增污.在此基础上,提出了燃煤工业锅炉大气污染物防治建议.     

A pilot study for determining the optimal operation condition for simultaneously controlling the emissions of PCDD/Fs and PAHs from the iron ore sintering process

In this study, the cost-benefit analysis technique was developed and incorporated into the Taguchi experimental design to determine the optimal operation combination for the purpose of providing a technique solution for controlling both emissions of PCDD/Fs and PAHs, and increasing both the sinter productivity (SP) and sinter strength (SS) simultaneously. Four operating parameters, including the water content, suction pressure, bed height, and type of hearth layer, were selected and all experimental campaigns were conducted on a pilot-scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant. The resultant optimal combination could reduce the total carcinogenic emissions arising from both emissions of PCDD/Fs and PAHs by 49.8%, and increase the sinter benefit associated with the increase in both SP and SS by 10.1%, as in comparison with the operation condition currently used in the real plant. The ANOVA results indicate that the suction pressure was the most dominant parameter in determining the optimal operation combination. The above result was theoretically plausible since the higher suction pressure provided more oxygen contents leading to the decrease in both PCDD/F and PAH emissions. But it should be noted that the results obtained from the present study were based on pilot scale experiments, conducting confirmation tests in a real scale plant are still necessary in the future.     

PCDD/F and "Dioxin-like" PCB emissions from iron ore sintering plants in the UK

Investigations have been carried out at the three Corus UK sinter plants over the period 2002-2004 to characterise the emissions of both 2,3,7,8-PCDD/Fs and WHO-12 PCBs, to estimate annual mass releases of these organic micro-pollutants using the I-TEF and WHO-TEF schemes, and to investigate the formation of PCBs in the iron ore sintering process. Results showed that the sintering of iron ore produces a characteristic WHO-12 PCB and PCDD/F congener pattern that is substantially the same for all UK sinter plants. With regard to WHO-12 PCBs, the most abundant congeners were typically PCBs 118 (6-9 ngNm(-3)), 105 (2-4 ngNm(-3)) and 77 (2-3 ngNm(-3)). All other WHO-12 PCBs were also detected at concentrations around 1 ngNm(-3). All sinter plants investigated exhibited very similar TEQ concentrations. WHO-12 PCB emissions were in the range 0.042-0.111 ngWHO-TEQNm(-3), whereas PCDD/F emissions ranged from 0.39 to 1.62 ngWHO-TEQNm(-3). PCDF congeners were the main contributors to the overall TEQ in sintering emissions (ca. 85%). Amongst WHO-12 PCBs, PCB 126 was the only noteworthy contributor to total TEQ (ca. 5-7%), a similar contribution to that from PCDDs. Based on the measurements that Corus UK has undertaken at these three sinter plants, annual mass releases of WHO-12 PCBs and PCDD/Fs have been calculated. For UK sinter plants, a total mass release of 29.5 g WHO-TEQ per annum [WHO-12 PCBs+PCDD/Fs] has been estimated, representing 9% of the total PCDD/F emissions to the UK atmosphere. Measurements were also carried out at a UK sinter plant to determine the windleg emission profile of WHO-12 PCBs. Results showed that WHO-12 PCBs were formed in the same regions of the sinter strand as 2,3,7,8-PCDD/Fs, indicating that there was a strong correlation between the formation of WHO-12 PCBs and PCDD/Fs in the iron ore sintering process.     

MnO2对煤粉中CaO固硫效率影响机理

采用热力学计算和实验方法对钙硫比n（CaO）/n（S）=2.0条件下不同钙基固硫剂的固硫效果进行了比较,发现：CaO的固硫效率最高。以CaO为固硫剂,研究了添加剂MnO2对CaO固硫效果的影响。结果表明,加入MnO2可以提高CaO的固硫效率,且其含量为1%时对CaO固硫的促进效果最佳。这是因为煤粉燃烧过程中MnO2将逐级分解,分解产物依次为Mn2O3和Mn3O4,锰的氧化物一方面可以催化CaO的固硫反应,另一方面,Mn3O4本身也参与到固硫反应之中,生成MnSO4,从而促进钙基固硫剂的固硫效果。     

Ceramic tiles with black pigment made from stainless steel plant dust: Physical properties and long-term leaching behavior of heavy metals

Stainless steel plant dust is a hazardous by-product of the stainless steelmaking industry. It contains large amounts of Fe, Cr, and Ni, and can be potentially recycled as a raw material of inorganic black pigment in the ceramic industry to reduce environmental contamination and produce value-added products. In this paper, ceramic tiles prepared with black pigment through recycling of stainless steel plant dust were characterized in terms of physical properties, such as bulk density, water absorption, apparent porosity, and volume shrinkage ratio, as well as the long-term leaching behavior of heavy metals (Cr, Ni, Pb, Cd, and Zn). The results show that good physical properties of ceramic tiles can be obtained with 8% pigments addition, sample preparation pressure of 25 MPa, and sintering at 1200 ºC for 30 min. The major controlling leaching mechanism for Cr and Pb from the ceramic tiles is initial surface wash-off, while the leaching behavior of Cd, Ni, and Zn from the stabilized product is mainly controlled by matrix diffusion. The reutilization process is safe and effective to immobilize the heavy metals in the stainless steel plant dust.

Implications: Stainless steel plant dust is considered as a hazardous material, and it can be potentially recycled for black pigment preparation in the ceramic industry. This paper provides the characteristics of the ceramic tiles with black pigment through recycling stainless steel plant dust, and the long-term leaching behavior and controlling leaching mechanisms of heavy metals from the ceramic tile. The effectiveness of the treatment process is also evaluated.     

Dioxins from thermal and metallurgical processes: recent studies for the iron and steel industry

In thermal metallurgical processes such as iron ore sintering and metal smelting operations, large flows of off-gases are generated. Mainly due to residue recycling in such processes, chlorine and volatile organics are always present in the feed. As a consequence of "de novo" formation, the off-gases from such processes typically contain dioxins in the range 0.3-30 ng I-TEQ/Nm3. So far there are only very few studies about the mechanisms of dioxin formation and destruction in these metallurgical processes. In an European Union (EU) research project "Minimization of dioxins in thermal industrial processes: mechanisms, monitoring and abatement (MINIDIP)", integrated iron and steel plant has been selected as one of the industrial sectors for further investigation. A large number of particulate samples (feed, belt siftings, electrofilter) were collected from the iron ore sintering installations from various steel plants and analyzed for their organochlorocompound contents. Measurable amounts of PCDD/F, PCBz, PCB were found for all samples. The various parameters influencing their de novo synthesis activity were also evaluated in laboratory experiments, and such activity was found to be moderate for samples from the ore sinter belt, but extremely high for some ESP dusts. Fine dust is active in a wide range of temperatures starting at 200 degrees C and declining above 450 degrees C; the optimal temperature for de novo synthesis was found to be around 350 degrees C; some inhibitors, such as triethanolamine, may reduce de novo activity by 50%, and lowering the O2 concentration in the gas stream leads to a much lower amount of PCDD/F formation. On the basis of their relative mass, typical operating conditions and specific activity of the different samples, the regions in the sintering plant where de novo synthesis may take place were tentatively established.     

Characterisation of volatile organic compounds and polycyclic aromatic hydrocarbons in the ambient air of steelworks

Investigations have been undertaken at two integrated steelworks in the UK to characterise airborne organic micro-pollutants and to assess the contribution of iron ore sintering and coke making operations on the air quality. Concentrations of volatile organic compounds (VOCs), namely benzene, toluene and p-xylene, were measured continuously within the boundary of a coking plant using for the first time differential optical absorption spectrometry (DOAS) between 2004 and 2006. Concentrations were obtained along two monitoring paths surrounding the coke plant and the average benzene concentration measured along both paths over the campaign was 28 μg m^?3. Highest benzene concentrations were associated with winds downwind of the coke oven batteries. Concentrations of polycyclic aromatic hydrocarbons (PAHs) in ambient air were measured during 27 consecutive days in 2005 at three different locations on an integrated steelworks. PAH profiles were determined for each sampling point and compared to coke oven and sinter plant emission profiles showing an impact from the steelworks. The mean benzo [a] pyrene concentration determined in the immediate vicinity of the coke ovens downwind from the battery was 19 ng m^?3, whereas for the two other sites average benzo [a] pyrene concentrations were much lower (around 1 ng m^?3). Data were analysed using principal components analysis (PCA) and results showed that coke making and iron ore sintering were responsible for most of the variation in the PAH concentrations in the vicinity of the investigated plant.     

Declining biodiversity in agricultural landscapes and the effectiveness of agri-environment schemes

Agricultural intensification, greatly accelerated as a result of the EU Common Agricultural Policy (CAP), has led to drastic reductions in the populations of many wild plant and animal species that used to be characteristic of farmland. In 1992, the EU provided the member states with its Agri-environment Regulation 2078/92 to help member states reverse these developments by means of agri-environment schemes. The question is: will the implementation of these schemes be sufficient to restore the biological diversity on farmland? Most studies that have examined the effectiveness of agri-environment schemes have focussed on farmland birds in Great Britain and The Netherlands. So far, the positive effects appear to be limited. Continuous evaluation and adaptation of these schemes is needed to enable the biodiversity on farmland to recover from the EU's former policy.     

Application of the Lime/Limestone Flue Gas Desulfurization Process to Smelter Gases

In this presentation, adaptation of the lime/limestone process for flue gas desulfurization (FGD) is discussed and how this process can be adapted to applications in the nonferrous smelting industry such as fugitive gases, copper reverberatory furnace gases, lead sintering gases, molybdenum roasting plant tail gases, and other weak SO₂ smelter gases. Different methods for particulate removal are also discussed with emphasis on how the particulate removal process can be integrated with the desulfurization process.