填料塔中钠碱溶液吸收低浓度SO2的体积传质系数

在填料吸收塔中测定和计算了钠碱溶液吸收烟气中低浓度SO2的体积总传质系数(KGa),并研究了进口气体中SO2浓度、气体流量、吸收液喷淋密度以及溶液中Na 浓度对体积传质总系数的影响.结果表明,进口气体中SO2浓度、气体流量及吸收液喷淋密度对KGa的影响较大;随着进口气体中SO2浓度的增大,KCa逐渐减小,而随着进口气体流量及吸收液喷淋密度的增大,KGa逐渐增大;吸收液中Na 浓度对KGa的影响较小.     

石灰石湿法脱硫过程中SO2吸收数学模型

为揭示石灰石湿法脱硫体系中喷淋塔内SO2的浓度和脱硫效率的变化情况,针对喷淋塔内石灰石在气膜控制、气液膜控制和固体溶解控制的3个不同阶段,以双膜理论为基础,以单个石灰石颗粒为研究对象,通过石灰石在不同阶段的转化率和粒径变化,得到SO2在不同阶段脱硫效率随时间的变化规律,建立SO2吸收的数学模型.模型计算结果表明,在烟气行程上,脱硫效率受SO2气膜传质阻力和石灰石溶解速率限制.在吸收塔底部和上端SO2吸收速率较低,在SO2和石灰石摩尔比在适宜条件下,有效吸收段高度为2 m左右.理论模型揭示的规律对喷淋塔的设计和运行参数选取有一定借鉴意义.     

乌鲁木齐市能源结构调整对冬季SO2浓度空间分布变化的影响

乌鲁木齐市冬季大气污染严重,SO2浓度不断增加,且超标频率增多,已成为不容忽视的环境问题.2012年乌鲁木齐市实施“煤改气”工程,旨在改善乌鲁木齐市的大气环境质量.为研究工程的实施对SO2浓度的控制起到的作用,选用冬季污染最为严重的时段(1-2月),对“煤改气”前后城市不同区域的SO2日均浓度变化进行了分析.结果显示,“煤改气”对SO2浓度的降低效果显著,但降低幅度在区域间存在差异,“煤改气”后冬季SO2日均浓度在空间上呈现出由南向北逐渐增加的态势,南面SO2日均浓度基本达标,而北面SO2浓度虽有降低,但超标频率依然较高,值得当地政府在环境治理过程中关注.     

中国火电行业SO2排污交易政策研究及框架设计

总结美国推行排污交易的发展历程及经验,从总量控制与排污交易的基本内涵出发,阐述排污交易的基本特征.立足于中国当前火电行业SO2排放总量控制的进程,综合分析当前火电行业SO2排放总量的控制方法、边际治理成本差异、定量化管理条件以及社会认同程度可以得出,中国已具有对火电行业实行SO2排污交易的基本条件.在此基础上,设计出中国火电行业实行SO2排污交易的框架体系.     

软锰矿浆烟气脱硫动力学研究

研究了软锰矿浆烟气脱硫工艺SO2与软锰矿反应的动力学特征,考察了搅拌强度、温度和SO2浓度等因素对反应速率的影响,计算出反应活化能和反应级数,建立了揭示SO2与软锰矿反应动力学特征的锰浸出速率方程.     

软锰矿浆烟气脱硫动力学研究

研究了软锰矿浆烟气脱硫工艺SO2与软锰矿反应的动力学特征,考察了搅拌强度、温度和SO2浓度等因素对反应速率的影响,计算出反应活化能和反应级数,建立了揭示SO2与软锰矿反应动力学特征的锰浸出速率方程.     

粘胶基活性炭纤维用于低浓度SO2常温脱除的实验研究

活性炭纤维(ACF)是一种新型功能性炭材料.应用粘胶基活性炭纤维(cellulose-ACF)对低浓度SO2(571mg/m3)进行吸附氧化实验,通过改变活性炭纤维量、SO2浓度、氧浓度,观察cellulose-ACF脱除低浓度SO2能力的变化规律.实验结果表明,随着活性炭纤维量、氧浓度的增加,cellulose-ACF对低浓度SO2的脱除能力增强.在此基础上展望活性炭纤维在大气环保领域的应用前景.     

好氧条件下生物转鼓同步脱硫脱硝性能及相应动力学模型的优化

为探究高效同步脱硫脱硝的生物工艺,以生物转鼓反应器为实验对象,研究了好氧条件下SO2质量浓度、NOx质量浓度、营养液体积和气体停留时间(EBRT)的变化对生物转鼓同步脱硫脱硝效果的影响,并用动力学模型拟合值与实验数据进行了对比.实验结果表明:生物转鼓同步脱硫脱硝最适条件为SO2质量浓度1200 mg·m-3,NOx质量...     

基于遗传算法的大气污染总量控制新方法

提出一种利用遗传算法进行大气污染总量控制的新方法,并以柳州市SO2总量控制为例说明这种方法的具体运用.遗传算法具备自适应全局搜索寻优特点,从控制点浓度推算源强分布,该源强分布满足总量控制的根本要求.该方法的具体实现是:将区域内各污染源的排放量编码为染色体,让染色体群体在模拟的进化环境下按生物进化规律进行优胜劣汰的自然选择,经过若干代的进化,最终得到的最优个体即代表最佳的源强分布.研究结果表明,这种方法是有效的和可行的.     

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.     

Evaluation of rational sulphur dioxide abatement in China

Sulphur dioxide (SO₂) abatement is attracting wide attention, with its generation increasing rapidly in China. In this paper, we calculate the SO₂ rational abatement ratio (SRAR) of 30 regions in China from 1990 to 2005, by applying Data Envelopment Analysis (DEA) based on the regional own production frontier. Results show that, the more developed area is, the lower SRAR is. The eastern, central and western areas have the lowest, medium and highest 1990-2005 average SRAR (22.17%, 46.99% and 58.28%), respectively. Chinese government should emphasise particularly on SO2 abatement in central and western area. More investment in SO2 management, introducing advanced technology as well as popularising clean coal technology are the urgent tasks for central and western area to improve SO2 emission efficiency.     

Modelling the spatial distribution of SO2 and NOx emissions in Ireland

The spatial distributions of sulphur dioxide (SO2) and nitrogen oxides (NOx) emissions are essential inputs to models of atmospheric transport and deposition. Information of this type is required for international negotiations on emission reduction through the critical load approach. High-resolution emission maps for the Republic of Ireland have been created using emission totals and a geographical information system, supported by surrogate statistics and landcover information. Data have been subsequently allocated to the EMEP 50 x 50-km grid, used in long-range transport models for the investigation of transboundary air pollution. Approximately two-thirds of SO2 emissions in Ireland emanate from two grid-squares. Over 50% of total SO2 emissions originate from one grid-square in the west of Ireland, where the largest point sources of SO2 are located. Approximately 15% of the total SO2 emissions originate from the grid-square containing Dublin. SO2 emission densities for the remaining areas are very low, < 1 t km-2 year-1 for most grid-squares. NOx emissions show a very similar distribution pattern. However, NOx emissions are more evenly spread over the country, as about 40% of total NOx emissions originate from road transport.     

Emissions from carpet combustion in a pilot-scale rotary kiln: comparison with coal and particle-board combustion

The use of post-consumer carpet as a potential fuel substitute in cement kilns and other high-temperature processes is being considered to address the problem of huge volumes of carpet waste and the opportunity of waste-to-energy recovery. Carpet represents a high volume waste stream, provides high energy value, and contains other recoverable materials for the production of cement. This research studied the emission characteristics of burning 0.46-kg charges of chopped nylon carpet squares, pulverized coal, and particle-board pellets in a pilot-scale natural gas-fired rotary kiln. Carpet was tested with different amounts of water added. Emissions of oxygen, carbon dioxide, nitric oxide (NO), sulfur dioxide (SO2), carbon monoxide (CO), and total hydrocarbons and temperatures were continuously monitored. It was found that carpet burned faster and more completely than coal and particle board, with a rapid volatile release that resulted in large and variable transient emission peaks. NO emissions from carpet combustion ranged from 0.06 to 0.15 g/MJ and were inversely related to CO emissions. Carpet combustion yielded higher NO emissions than coal and particle-board combustion, consistent with its higher nitrogen content. SO2 emissions were highest for coal combustion, consistent with its higher sulfur content than carpet or particle board. Adding water to carpet slowed its burn time and reduced variability in the emission transients, reducing the CO peak but increasing NO emissions. Results of this study indicate that carpet waste can be used as an effective alternative fuel, with the caveats that it might be necessary to wet carpet or chop it finely to avoid excessive transient puff emissions due to its high volatility compared with other solid fuels, and that controlled mixing of combustion air might be used to control NO emissions from nylon carpet.     

The effects of sulphur dioxide on the parasitism of the rust fungus Uromyces viciae-fabae on Vicia faba

Vicia faba cv. Aguadulce was grown in fumigation chambers ventilated with filtered air or air containing sulphur dioxide (SO(2)) at controlled concentrations, and inoculated with the rust fungus Uromyces viciae-fabae. The influence of the pollutant was rated in terms of production of uredia and dehiscent urediospores. Exposures to SO(2) levels around 70-90 nl litre(-1) enhanced uredia density. Pre-inoculation fumigations at 70-86 nl litre(-1) increased uredia density, whilst post-inoculation fumigations stimulated urediospore production. Lower concentrations increased diffusion resistance of the host plant and slightly increased uredia density. Concentrations between 100 and 130 nl litre(-1) were somewhat inhibitory for the parasite, even in the absence of any visible damage symptoms on the host. Total sulphur accumulation in leaf tissue was reduced by the presence of the fungal infection. Growing under SO(2) pollution neither decreased germination ability nor modified morphological parameters of the urediospores. However, elongation of the germination tube of spores coming from filtered air was adversely affected by the pollutant.     

燃煤工业锅炉排放二氧化硫对大气的污染及工业固硫型煤的应用

本文论述了我国燃煤工业锅炉排放ＳＯ２对大气污染的状况及发展趋势,以及应用工业固硫型煤控制燃煤工业锅炉对大气的污染。燃煤工业锅炉燃烧工业固硫型煤时,可明显地降低ＳＯ２和烟尘的排放量,并节约煤炭。在当前及今后相当长的时期内,推广和发展工业固硫型煤,是防治燃煤工业锅炉大气ＳＯ２污染的一条投资少、见效快、简便易行的实用措施,其经济效益及环境效益相当可观。     

Boiler briquette coal versus raw coal: Part II--Energy, greenhouse gas, and air quality implications

The objective of this paper is to conduct an integrated analysis of the energy, greenhouse gas, and air quality impacts of a new type of boiler briquette coal (BB-coal) in contrast to those of the raw coal from which the BB-coal was formulated (R-coal). The analysis is based on the source emissions data and other relevant data collected in the present study and employs approaches including the construction of carbon, energy, and sulfur balances. The results show that replacing R-coal with BB-coal as the fuel for boilers such as the one tested would have multiple benefits, including a 37% increase in boiler thermal efficiency, a 25% reduction in fuel demand, a 26% reduction in CO2 emission, a 17% reduction in CO emission, a 63% reduction in SO2 emission, a 97% reduction in fly ash and fly ash carbon emission, a 22% reduction in PM2.5 mass emission, and a 30% reduction in total emission of five toxic hazardous air pollutant (HAP) metals contained in PM10. These benefits can be achieved with no changes in boiler hardware and with a relatively small amount of tradeoffs: a 30% increase in PM10 mass emission and a 9-16% increase in fuel cost.     

Simulation of stack plume opacity

The visual impact of primary particles emitted from stacks is regulated according to stack opacity criteria. In-stack monitoring of the flue gas opacity allows plant operators to ensure that the plant meets U.S. Environmental Protection Agency opacity regulations. However, the emission of condensable gases such as SO3 (that hydrolyzes to H2SO4), HCl, and NH3, which may lead to particle formation after their release from the stack, makes the prediction of stack plume opacity more difficult. We present here a computer simulation model that calculates the opacity due to both primary particles emitted from the stack and secondary particles formed in the atmosphere after the release of condensable gases from the stack. A comprehensive treatment of the plume rise due to buoyancy and momentum is used to calculate the location at which the condensed water plume has evaporated (i.e., where opacity regulations apply). Conversion of H2SO4 to particulate sulfate occurs through nucleation and condensation on primary particles. A thermodynamic aerosol equilibrium model is used to calculate the amount of ammonium, chloride, and water present in the particulate phase with the condensed sulfate. The model calculates the stack plume opacity due to both primary and secondary particles. Examples of model simulations are presented for three scenarios that differ by the emission control equipment installed at the power plant: (1) electrostatic precipitators (ESP), (2) ESP and flue gas desulfurization, and (3) ESP and selective catalytic reduction. The calculated opacity is most sensitive to the primary particulate emissions. For the conditions considered here, SO3 emissions showed only a small effect, except if one assumes that most H2SO4 condenses on primary particles. Condensation of NH4Cl occurs only at high NH3 emission rates (about 25 ppm stack concentration).     

印刷环节挥发性有机物无组织排放特征测定研究

对使用溶剂型油墨的凹版印刷设备和使用水性油墨的柔版印刷设备无组织排放的挥发性有机物(VOCs)浓度进行了实际监测,并采用计算流体动力学模拟无组织排放VOCs的收集效率。结果表明：(1)使用溶剂型油墨的凹版连续印刷过程非甲烷总烃(NMHC)最高均值达到5 975.67 mg/m³,约为使用水性油墨的柔版印刷(191.67 mg/m³)的31.2倍。虽然使用水性油墨可明显降低NMHC的排放,但其操作空间的浓度依然存在超过《工作场所有害因素职业接触限值第1部分：化学有害因素》(GBZ 2.1—2019)的现象。(2)印刷车间应该设置专门的调墨室,能缓解印刷车间内挥发性污染气体浓度的波动。(3)计算流体动力学模拟显示,设置合理的集气罩可有效降低VOCs的无组织排放,收集效率为70%～75%。     

Inorganic acid emission factors of semiconductor manufacturing processes

A huge amount of inorganic acids can be produced and emitted with waste gases from integrated circuit manufacturing processes such as cleaning and etching. Emission of inorganic acids from selected semiconductor factories was measured in this study. The sampling of the inorganic acids was based on the porous metal denuders, and samples were then analyzed by ion chromatography. The amount of chemical usage was adopted from the data that were reported to the Environmental Protection Bureau in Hsin-chu County according to the Taiwan Environmental Protection Agency regulation. The emission factor is defined as the emission rate (kg/month) divided by the amount of chemical usage (L/month). Emission factors of three inorganic acids (i.e., hydrofluoric acid [HF], hydrochloric acid [HCl], and sulfuric acid [H2SO4]) were estimated by the same method. The emission factors of HF and HCl were determined to be 0.0075 kg/L (coefficient of variation [CV] = 60.7%, n = 80) and 0.0096 kg/L (CV = 68.2%, n = 91), respectively. Linear regression equations are proposed to fit the data with correlation coefficient square (R2) = 0.82 and 0.9, respectively. The emission factor of H2SO4, which is in the droplet form, was determined to be 0.0016 kg/L (CV = 99.2%, n = 107), and its R2 was 0.84. The emission profiles of gaseous inorganic acids show that HF is the dominant chemical in most of the fabricators.