烟气脱硫吸收塔增容改造技术方案探讨

目前国内投运的部分石灰石—石膏湿法脱硫装置中,由于燃煤硫分变化而面临着吸收塔增容改造的局面。以实际案例探讨国内燃煤电厂脱硫装置吸收塔增容改造的常用技术方案,并比较分析其优缺点。吸收塔增容改造项目应本着因地制宜的原则,结合原塔性能分析、实际设计参数、现场场地、工程投资等因素,进行多方案技术经济比较,寻求适合该改造项目的最优方案。     

湿法脱硫装置SO2吸收系统增容改造方案探讨

国内越来越多火电厂石灰石—石膏湿法脱硫装置因燃煤硫分变化及其他原因需要进行增容改造。介绍了湿法烟气脱硫装置核心SO2吸收系统4种可行的增容改造方案,即塔外浆液箱方案、串联塔方案、并联塔方案、吸收塔重建方案,并对各方案的优缺点和适应性进行比较和论述,为同类烟气脱硫装置增容改造工程提供参考。     

火电厂脱硫吸收塔临时烟囱的选型设计

为了解决不设置烟气加热设备（以下简称GGH）后电厂主烟囱防腐和烟道改造施工而影响机组正常运行这一难题,在脱硫塔顶部设置临时烟囱排放烟气。以安阳电厂烟气脱硫工程为实例,从工艺、环境影响、制造和施工安装等方面具体介绍了脱硫吸收塔临时烟囱的设计,为不设GGH的脱硫技改工程提供参考。     

湿法烟气脱硫吸收塔系统的设计和运行分析

详细介绍了广东省连州电厂石灰石／石膏湿法烟气脱硫吸收塔系统的流程，设备，吸收塔内部结构、防腐措施等设计情况，同时对系统的运行状况进行了分析。     

加拿大Lambton电厂湿式石灰石─石膏脱硫工艺的运行经验

介绍了加拿大Lambton电厂的两套石灰石一石膏法烟气脱硫系统的工艺流程，系统运行初期出现的主要问题及采取的解决措施，包括吸收塔内村的渗漏、喷嘴的堵塞、入口烟近的改造、氧化槽壁面结垢和玻璃纤维喷淋管道的磨损等问题。     

PBA添加剂在湿法脱硫系统中的应用

当前火电厂燃煤硫分普遍超出设计值,吸收塔入口SO2浓度过大,同时环境保护要求越来越严格,火电厂烟气中SO2浓度很难达标排放,为此脱硫装置迫切需要进行提高脱硫效率的增容改造。针对上述情况,介绍了一种使用新型复合有机酸添加剂PBA来满足脱硫系统设计脱硫效率的解决方案,探讨了PBA添加剂工作原理及使用方法,并就其在节能降耗方面的应用实例进行了分析。     

火电厂烟气脱硫装置吸收塔倒装工艺

吸收塔是火电厂烟气脱硫装置中的关键设备,以铜陵电厂2×1 000MW机组烟气脱硫装置吸收塔安装为例,介绍了吸收塔倒装工艺及其特点。由于倒装法在降低费用、缩短工期、减少高空作业量、不受场地限制等方面具有显著的优点,因而在吸收塔的施工技术中被广泛采用。     

烟气循环流化床-悬浮吸收工艺的应用

详述了烟气循环流化床悬浮吸收工艺的脱硫原理、工艺流程、系统组成,为类似老电厂烟气脱硫工程改造提供有益的设计和管理经验。     

珠海发电厂脱硫改造及其运行调整

介绍珠海发电厂2×700 MW机组脱硫系统增容及取消旁路的实际改造情况，探讨了脱硫改造后系统运行的相关调整措施，确保了机组的安全、环保运行。     

600MW机组湿法脱硫吸收塔溢流原因分析及对策

阐述了火电厂600MW机组石灰石—石膏湿法脱硫系统吸收塔浆液溢流的危害,分析了吸收塔浆液溢流的原因,主要是石膏浆液品质差、氧化风量不合理、浆液循环泵、浆液喷淋的影响,溢流管接口位置布置不合理等。通过适当降低运行液位、合理布置吸收塔溢流管道等措施解决了吸收塔浆液溢流问题,确保脱硫系统稳定运行。     

Programs assessing implementation and effectiveness of state forest practice rules and BMPs in the West

The major forest nonpoint source control programs in the West are largely regulatory, either under forest practices acts (California, Idaho, New Mexico, Nevada, Oregon, and Washington) or a streamside management act (Montana). These programs and the specific rules they enforce continue to undergo intensive scrutiny. Still, the questions are the same for these regulatory programs as for states that base nonpoint source control on voluntary BMPs (Arizona, Colorado, Utah, Wyoming). Are the rules or BMPs being applied, and are they effective in reducing nonpoint source pollution to levels that protect beneficial uses of water? The level of debate about forestry in the West has resulted in detailed monitoring and research to answer these questions. In the past, state agencies have assumed levels of BMP compliance based on the percent of operations without enforcement actions. These estimates are being replaced by statistically valid and reproducible monitoring of forest practices rules and BMP compliance levels. BMP effectiveness is being assessed using both qualitative and quantitative methods. This can involve field assessments, process-based research, and control watershed studies. Some trend monitoring is also beginning. With the regional implementation rate for forestry BMPs at about 94% and rising, it is likely that effectiveness testing will continue to be a priority and consume the majority of assessment resources for this region.     

Effect of Coconut, Sisal and Jute Fibers on the Properties of Starch/Gluten/Glycerol Matrix

Coconut, sisal and jute fibers were added as reinforcement materials in a biodegradable polymer matrix comprised of starch/gluten/glycerol. The content of fibers used in the composites varied from 5% to 30% by weight of the total polymers (starch and gluten). Materials were processed in a Haake torque rheometer (120 °C, 50 rpm) for 6 min. The mixtures obtained were molded by heat compression and further characterized. Addition of lignocellulosic fibers in the matrix decreased the water absorption at equilibrium. The diffusion coefficient decreased sharply around 5% fiber concentration, and further fiber additions caused only small variations. The thermogravimetric (TG) analysis revealed improved thermal stability of matrix upon addition of fibers. The Young’s modulus and ultimate tensile strength increased with fiber content in the matrix. The storage modulus increased with increasing fiber content, whereas tanδ curves decreased, confirming the reinforcing effect of the fibers. Morphology of the composites analyzed under the scanning electron microscope (SEM) exhibited good interfacial adhesion between the matrix and the added fibers. Matrix degraded rapidly in compost, and addition of increased amounts of coconut fiber in the matrix caused a slowdown the biodegradability of the matrix. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may be suitable.     

Quantification of Polymerisation Processes During The Oxidative Degradation of 14C-Labelled Chlorophenols

In experiments employing the lignocellulose-decaying basidiomycetes Trametes versicolor and Stropharia rugosoannulata degrading uniformly¹⁴C-labelled 2,4-dichlorophenol and pentachlorophenol, acombination of size exclusion chromatography (SEC),fractionation, and -scintillation counting wasapplied to quantify polymerisation products formed duringchlorophenol degradation. Time-dependent mass balances weregenerated by analysis of ¹⁴C in polymerisation products,CO₂, as well as monomer non-polar and polar metabolites.Approximately 30% of the chlorophenols were found to bepolymerised. A major fraction of the polymerised productscorresponded to a molecular weight range from 0.24 – 40 kDa.Only a minor fraction could be attributed to a molecularweight >40 kDa. This method proved to be useful inquantification of polymerisation products and kinetics of thepolymerisation processes, whereas UV/Vis detection ofpolymerisation products separated by SEC led to false positiveresults. The SEC-¹⁴C method could also be applied forother complex processes where polymerisation ordepolymerisation occurs (humification, degradation oflignocellulose, formation of bound residues from xenobioticssuch as polycyclic aromatic hydrocarbons or 2,4,6-trinitrotoluene) and where spectrophotometric determinationsare difficult or impossible.     

The Relative Influences of Primary and Secondary Particulates to Urban Air Quality in the United Kingdom

This study uses a combination of data from U.K. monitoringstations and from modelling undertaken with the U.K.Meteorological Office's NAME Model to investigate therelative influences of primary and secondary particulateson total PM₁₀ levels at sites in the United Kingdom. Co-located PM₁₀ and sulphate aerosol measurementsindicate that sulphate has a disproportionately largeinfluence on the variation of PM₁₀ levels incomparison to its contribution to their total mass.Comparisons of measured PM₁₀ at urban centre, roadsideand rural sites suggest that local primary sources havevery little influence on daily mean levels. NAME has beenused to model both primary particles and sulphate aerosolfrom sources across the whole of Europe. The discrepanciesbetween modelled and observed PM₁₀ suggest that coarseparticles, such as windblown dust and resuspended roaddust,may comprise a very large, if not dominant, proportion ofobserved PM₁₀ levels. The apparently minor role ofprimary particles (especially locally-sourced ones) raisesa number of issues regarding the suitability of current U.K.and European legislation to addressing the particle problem.     

Hysteresis in Reversal of Central European Mountain Lakes from Atmospheric Acidification

Extremely high emissions of S and N compounds in Central Europe (both 280 mmol m^-2 yr^-1) declined by 70and 35%, respectively, during the last decade. Decreaseddeposition rates of SO₄ ^-2, NO₃ ^-, and NH₄ ⁺ in the region paralleled emission declines. The reduction in atmospheric inputs of S and N to mountain ecosystemshas resulted in a pronounced reversal of acidification in the Tatra Mountains and Bohemian Forest lakes. Between the 1987–1990and 1997–1999 periods, concentrations of SO₄ ^-2 and NO₃ ^- decreased (average ± standard deviation) by 22±7 and 12±7 mol L^-1, respectively, in theTatra Mountains, and by 19±7 and 15±10 mol L^-1, respectively, in the Bohemian Forest. Their decrease was compensated in part (1) by a decrease in Ca²⁺ + Mg²⁺ (17±7 mol L^-1) and H⁺ (4±6 mol L^-1), and an increase in HCO₃ ^-(10±10 mol L^-1) in the Tatra Mountains lakes, and (2) by a decrease in Al (7±4 mol L^-1), Ca²⁺ + Mg²⁺ (9±6 mol L^-1), and H⁺ (6±5 mol L^-1), in Bohemian Forest lakes. Despite the rapid decline in lake water concentrations of SO₄ ^-2 and NO₃ ^- in response to reduced S and N emissions, their present concentrations in some lakes are higher than predictionsbased on observed concentrations at comparable emission rates during development of acidification. This hysteresis in chemical reversal from acidification has delayed biological recovery of the lakes. The only unequivocal sign of biological recovery hasbeen observed in erné Lake (Bohemian Forest) where a cladoceran species Ceriodaphnia quadrangular has recentlyreached its pre-acidification abundance.     

Reconstruction of Long-Term Changes in Lake water Chemistry,Zooplankton and Benthos of a Small,Acidified High-Mountain Lake: Magic Modelling and Palaeolimnogical Analysis

Starolesnianske pleso is a small and shallow acid lake in the High Tatra Mountains, situated at 2000 m above sea level, on granitic bedrock, with sparse and thin soil cover. When detailed measurements began in the 1980s Starolesnianske pleso had pH below 5 and only one species of cladoceran zooplankton, the ubiquitous Chydorus sphaericusPalaeolimnological investigations show changes in cladoceran zooplankton and chironomid zoobenthic assemblages since about 1920 and a major change in 1970–1980. The dynamic acidification model MAGIC was used to reconstruct changes in water chemistry over the past 150 years. The results from MAGIC agree well with the sediment record; pH levels gradually decreased from 6.5 in the mid-1800s to about 5.6 in 1920 (first response in biota) to below 5.0 by 1970, and concentrations of inorganic aluminium rose dramatically beginning about 1960. In the 1990s the lake water chemistry showed clear signs of reversal in acidification brought about by a major decline in S deposition.     

Changes in Extractability of Cr and Pb in a Polycontaminated Soil After Bioaugmentation With Microbial Producers of Biosurfactants, Organic Acids and Siderophores

Partly because of the low bioavailability of metals, the soil cleaning-up using phytoremediation is usually time-consuming. In order to enhance the amount of metals at the plant's disposal, the soil bioaugmentation coupled together with phytoextraction is an emerging technology. In this preliminary work, two agricultural soils which mainly differed in their Cr, Hg and Pb contents (LC, low-contaminated soil; HC, high-contaminated soil) were bioaugmented in laboratory conditions by either bacterial (Bacillus subtilis, Pseudomonas aeruginosa, Pseudomonas fluorescens or Ralstonia metallidurans) or fungal inocula (Aspergillus niger or Penicillium simplicissimum) and incubated during three weeks. The LC soil pots bioaugmented with A. niger and P. aeruginosa contained higher concentrations of Cr (0.08 and 0.25 mg.kg⁻¹ dw soil) and Pb (0.25 and 0.3 mg.kg⁻¹ dw soil) in the exchangeable fraction F1 (extraction with MgCl₂) by comparison with the non-bioaugmented soil where neither Cr nor Pb was detected. Conversely, immobilization of Cr and Pb in the soil were observed with the other microorganisms. The soil bioaugmentation not only modified the metal speciation for the most easily extractable fractions but also modified the distribution of metals in the other fractions, to a lesser extent nevertheless. The difference in microbial concentrations between the bioaugmented or not HC soils reached up to 1.8 log units. Thus the microorganisms that we chose for the soil bioaugmentation were competitive towards the indigenous microflora. The PCA analysis showed close positive relationships between the microorganisms which potentially produced siderophores in the soil and the amount of Cr and Pb in the fraction F1.     

Heavy Metals Removal by Biosorption and Flotation

The removal of a mixture of heavy (toxic) metal cations (copper, nickeland zinc) from liquid effluents was investigated in this study at pilotscale, using counter-current contact mode. The innovative processinvolved the abstraction of metal ions onto fungal biosorbents, followedby the application of flotation for the subsequent solid/liquid separationof biomass particles. The ability of microorganisms to remove metal ionsfrom aqueous solutions is a well-known phenomenon. Nevertheless,engineering considerations are very important in decisions, concerningthe commercial future of biosorption and practical solutions are neededfor certain problems, such as the efficient post-separation ofmetal-loaded biomass. The two processes (flotation and biosorption) caneffectively operate in combination, in what it was termed biosorptiveflotation process. The sorbents may be recycled, after appropriate elutionof metals, as well as the treated (clean) water.     

酸浸出法回收冶金污泥中的有价金属

采用二次酸浸出的方法回收镍钴湿法冶金工业污泥中的有价金属。先采用水和硫酸作为浸出剂浸出Mg和Na,最佳工艺条件为浸出液的pH 7.5、浸出时间5 min、浸出剂体积与干污泥质量的比(ω)为10 mL/g。再采用硫酸作为浸出剂、焦亚硫酸钠作为还原剂进行二次酸浸,在硫酸与污泥质量比为1.3、焦亚硫酸钠与污泥质量比为0.3、ω为5 mL/g、浸出温度85℃、浸出时间20 min的最佳工艺条件下,Co、Ni、Cu、Mn和Zn的浸出率分别达92.45%、93.48%、89.52%、97.78%和94.79%。经XRD表征,浸出后污泥中未见原污泥中的矿物相,说明原污泥中的矿物几乎全部被溶解。     

不同原料生物炭对NH4+-N、PO43--P吸附性能的差异性及其成因分析

以芦苇、小麦秸秆和竹子为原料,利用回流式炭化工艺制备3种生物炭。比较三者对NH_4~+-N、PO_4~(3-)-P的吸附性能,并对三者吸附性能差异的成因进行分析。实验结果表明:3种生物炭对PO_4~(3-)-P的吸附效果整体上优于NH_4~+-N,因为3种生物炭的阳离子交换容量CEC值和Zeta电位绝对值的水平均较低,不利于阳离子的吸附;竹炭Z-C对NH_4~+-N的吸附效果最佳,6 h去除率为3.59%,低的N含量、pH及Zeta电位绝对值对NH_4~+-N的吸附有利;芦苇炭LW-C中的O更多地与K、Mg等结合,形成能够与PO_4~(3-)反应生成磷酸盐沉淀或者晶体物质的金属氧化物,从而具有最好的PO_4~(3-)-P的吸附效果,6 h时去除率达16.91%。