湿法烟气脱硫工艺中烟气再热方式的选择

分析了湿法烟气脱硫烟气再热原因,介绍了多种烟气再热方法,并对其进行了技术分析,为湿法烟气脱硫工程的烟气再热系统设计提供了依据。     

烟道式脱硫装置处理冶炼厂高浓度SO2烟气的工程实践

本文介绍了烟道式脱硫装置的特点及工艺原理 ,采用该装置处理某冶炼厂高浓度SO2 烟气 ,其脱硫率达 90 %以上 ,净化后的烟气可直接达标排放 ,并年产合格脱硫石膏近万吨。烟道式脱硫装置解决了常规脱硫除尘装置共同存在的结垢和堵塞问题 ,在冶炼烟气治理方面具有一定的推广应用价值。     

吸附法烟气脱硫

燃油和煤炭在燃烧过程中会产生SO2 ,这些SO2 排入大气中 ,形成酸雨 ,严重破坏生态环境 ,危害人类健康。一个世纪以来 ,人们对烟气脱硫作出了很大的努力 ,但常见的脱硫技术具有投资大、运行费用高 ,甚至有二次污染等问题。吸附法烟气脱硫工艺简单、脱硫效率高 ,是一种具有深入研究价值与应用前景的方法     

火化过程中二噁英类污染物减排技术研究

为减少火化过程中二噁英类污染物的排放,研究了"热交换器 布袋除尘器 活性炭纤维毡"三级组合对火化遗体烟气中二噁英类污染物的去除效果.利用急冷技术将二次燃烧室排出的火化烟气温度降到90～130℃.实验表明,布袋除尘器去除火化烟气中二噁英类污染物的效率为57.4%;布袋除尘器分别与厚度为5、15 mm的活性炭纤维毡组合去除火化烟气中二噁英类污染物的效率分别为64.0%和89.2%.     

半干半湿法烟气脱硫技术的工业应用研究

探讨了日本半干半湿法脱硫除尘系统和中国环境科学研究院半干半湿法烟气脱硫除尘示范系统的主要差别 ,研究了半干半湿法烟气脱硫技术在出塔烟气温度、钙硫摩尔比和循环粉煤灰返灰等方面对脱硫效率的影响。结果表明 ,在脱硫塔出口烟气温度为 78℃、m(循环粉煤灰返灰 )∶ m(石灰 )为 1∶ 4、n( Ca)∶ n( S) <1.2时 ,脱硫效率达 85 .1%;在 n( Ca)∶ n( S) =1.4时 ,脱硫效率可达 88.3 %。     

燃煤烟气汞污染控制技术研究进展

针对近年来的燃煤烟气汞污染控制技术的发展现状,综述了吸附脱汞和氧化脱汞技术的最新研究进展,重点介绍了活性炭吸附剂吸附脱汞技术和光催化氧化脱汞技术.鉴于活性炭吸附脱汞和光催化氧化脱汞都同时存在吸附和氧化2种反应,提出吸附—光催化脱汞技术将成为今后燃煤烟气汞污染控制的研究方向.     

Active methods of mercury removal from flue gases

Due to its adverse impact on health, as well as its global distribution, long atmospheric lifetime and propensity for deposition in the aquatic environment and in living tissue, the US Environmental Protection Agency (US EPA) has classified mercury and its compounds as a severe air quality threat. Such widespread presence of mercury in the environment originates from both natural and anthropogenic sources. Global anthropogenic emission of mercury is evaluated at 2000 Mg year⁻¹. According to the National Centre for Emissions Management (Pol. KOBiZE) report for 2014, Polish annual mercury emissions amount to approximately 10 Mg. Over 90% of mercury emissions in Poland originate from combustion of coal.

The purpose of this paper was to understand mercury behaviour during sub-bituminous coal and lignite combustion for flue gas purification in terms of reduction of emissions by active methods. The average mercury content in Polish sub-bituminous coal and lignite was 103.7 and 443.5 μg kg⁻¹. The concentration of mercury in flue gases emitted into the atmosphere was 5.3 μg m⁻³ for sub-bituminous coal and 17.5 μg m⁻³ for lignite. The study analysed six low-cost sorbents with the average achieved efficiency of mercury removal from 30.6 to 92.9% for sub-bituminous coal and 22.8 to 80.3% for lignite combustion. Also, the effect of coke dust grain size was examined for mercury sorptive properties. The fine fraction of coke dust (CD) adsorbed within 243–277 μg Hg kg⁻¹, while the largest fraction at only 95 μg Hg kg⁻¹. The CD fraction < 0.063 mm removed almost 92% of mercury during coal combustion, so the concentration of mercury in flue gas decreased from 5.3 to 0.4 μg Hg m⁻³. The same fraction of CD had removed 93% of mercury from lignite flue gas by reducing the concentration of mercury in the flow from 17.6 to 1.2 μg Hg m⁻³. The publication also presents the impact of photochemical oxidation of mercury on the effectiveness of Hg vapour removal during combustion of lignite. After physical oxidation of Hg in the flue gas, its effectiveness has increased twofold.

     

电子束半干法烟气净化技术

电子束烟气净化技术由于能够同时脱除烟气中的SO2 和NOx 而得到世界各国环保界的重视。传统的电子束烟气净化技术在工业应用中存在能耗高、副产品黏结严重、工作可靠性低等问题。新型电子束半干法烟气净化技术解决了传统工艺在工业化应用中存在的问题 ,可以在较小的辐照剂量下获得更为理想的烟气净化效果 ,提高了系统的工作可靠性 ,是一项工业应用前景十分广阔的环保技术。     

电子束氨法烟气脱硫技术工艺研究

介绍了位于四川省绵阳市科学城热电厂的电子束氨法烟气脱硫脱硝工业试验装置和在该装置上进行的较全面的工艺研究 ,确定了影响SO2 脱除效率的主要参数 ,为北京京丰热电EA FGD工业示范工程设计提供了重要依据     

脱硫石膏农业利用研究进展与展望

概述火电厂脱硫石膏定义、生产过程和性质.简述了脱离石膏的工业利用,详述了脱离石膏对酸性和碱性土壤改良的现状和机理,并展望了脱硫石膏促进滩涂土植被演替的前景.     

湿式等离子体烟气脱硫试验研究

介绍了湿式等离子体烟气脱硫试验，研究了模拟烟气参数、反应器结构和放电特性等因素对脱硫效率的影响，实验表明，试验结果为工业性应用提供了基本资料。     

填料塔应用于烟道气治理时设计中应注意的问题探讨

论述了填料塔烟道气治理装置的填料层及塔内件的设计,并和传统的塔型尺寸及各种参数进行了比较。     

Control of mercury vapor emissions from combustion flue gas

GOAL, SCOPE AND BACKGROUND: Mercury (Hg) emission from combustion flue gas is a significant environmental concern due to its toxicity and high volatility. A number of the research efforts have been carried out in the past decade exploiting mercury emission, monitoring and control from combustion flue gases. Most recently, increasing activities are focused on evaluating the behavior of mercury in coal combustion systems and developing novel Hg control technologies. This is partly due to the new regulatory requirement on mercury emissions from coal-fired combustors to be enacted under the U.S. Title III of the 1990 Clean Air Act Amendments. The aim of this review work is to better understand the state-of-the-art technologies of flue gas mercury control and identify the gaps of knowledge hence areas for further opportunities in research and development. MAIN FEATURES: This paper examines mercury behaviors in combustion systems through a comprehensive review of the available literature. About 70 published papers and reports were cited and studied. RESULTS AND DISCUSSION: This paper summarizes the mechanisms of formation of mercury containing compounds during combustion, its speciation and reaction in flue gas, as well as subsequent mobilization in the environment. It also provides a review of the current techniques designed for real-time, continuous emission monitoring (CEM) for mercury. Most importantly, current flue gas mercury control technologies are reviewed while activated carbon adsorption, a technology that offers the greatest potential for the control of gas-phase mercury emissions, is highlighted. CONCLUSIONS AND RECOMMENDATIONS: Although much progress has been achieved in the last decade, techniques developed for the monitoring and control of mercury from combustion flue gases are not yet mature and gaps in knowledge exist for further advancement. More R&D efforts are required for the effective control of Hg emissions and the main focuses are identified.     

脱硫石膏农业利用研究进展与展望

概述火电厂脱硫石膏定义、生产过程和性质。简述了脱离石膏的工业利用，详述了脱离石膏对酸性和碱性土壤改良的现状和机理，并展望了脱硫石膏促进滩涂土植被演替的前景。     

氧化镁基催化吸附剂的制备及脱硝性能研究

采用共混合法制备氧化镁基催化吸附剂,通过正交实验设计找出其组分的最佳配比.利用该催化吸附剂对烟气进行脱硝实验,考察了焙烧温度、焙烧时间和床层温度对氧化镁基催化吸附剂去除NO的影响.结果表明,利用氧化镁基催化吸附剂可以对烟气进行直接催化分解脱硝,其最佳的焙烧温度和时间分别为350～500 ℃和3～4 h,脱硝率可达85%～95%.利用红外光谱(FT-IR)、X射线衍射(XRD)对脱硝处理前后的氧化镁基催化吸附剂进行了分析,探讨其脱硝的机制.     

气升式反应器中微生物烟气脱硫研究

基于微生物酸性铁溶液烟气脱硫特性,实验构建了一套内循环气升式反应器.在反应器中,利用处于对数生长期的氧化亚铁硫杆菌(Thiobacillus ferrooxidans)酸性铁溶液进行了模拟烟道气SO2脱除实验研究.为寻求高脱硫率,实验研究了铁离子浓度、入口氧含量、细菌数和pH值的变化对脱硫率的影响.考察了反应液中Fe(Ⅱ)离子浓度的变化规律.实验表明,含T.f菌酸性铁溶液的脱硫效果较高;Fe离子浓度在7.67 g/L左右时脱硫率最佳;入口气中氧含量、反应液中细菌数和pH值越高,反应液的脱硫率也就越高.反应液中的Fe(Ⅱ)离子浓度是一先扬后抑的变化过程.     

软锰矿浆烟气脱硫反应器试验研究

研究了喷射鼓泡反应器 (JBR)的桨叶直径、桨叶埋深和气体喷射管分布等结构参数对脱硫率和锰浸出率的影响 ,从而优化了反应器结构。     

Spray-dry desulfurization of flue gas from heavy oil combustion

An experimental investigation on sulfur dioxide removal in a pilot-scale spray dryer from the flue gas generated by combustion of low-sulfur (S) heavy oil is reported. A limewater slurry was sprayed through an ultrasonic two-fluid atomizer in the spray-dry chamber, and the spent sorbent was collected downstream in a pulse-jet baghouse together with fly ash. Flue gas was sampled at different points to measure the desulfurization efficiency after both the spray-dry chamber and the baghouse. Parametric tests were performed to study the effect of the following variables: gas inlet temperature, difference between gas outlet temperature and adiabatic saturation temperature, lime-to-S ratio, and average size of lime particles in the slurry. Results indicated that spray drying is an effective technology for the desulfurization of low-S fuel oil flue gas, provided operating conditions are chosen carefully. In particular, the lowest gas inlet and outlet temperatures compatible with baghouse operation should be selected, as should a sufficiently high lime-to-S ratio. The attainment of a small lime particle size in the slurry is critical for obtaining a high desulfurization efficiency. A previously presented spray-dry flue gas desulfurization model was used to simulate the pilot-scale desulfurization tests, to check the ability of the model to predict the S capture data and its usefulness as a design tool, minimizing the need for pilot-scale experimentation. Comparison between model and experimental results was fairly good for the whole range of calcium/S ratios considered.     

Predicting extents of mercury oxidation in coal-derived flue gases

The proposed mercury (Hg) oxidation mechanism consists of a 168-step gas phase mechanism that accounts for interaction among all important flue gas species and a heterogeneous oxidation mechanism on unburned carbon (UBC) particles, similar to established chemistry for dioxin production under comparable conditions. The mechanism was incorporated into a gas cleaning system simulator to predict the proportions of elemental and oxidized Hg species in the flue gases, given relevant coal properties (C/H/O/N/S/Cl/Hg), flue gas composition (O2, H2O, HCl), emissions (NO(X), SO(X), CO), the recovery of fly ash, fly ash loss-on-ignition (LOI), and a thermal history. Predictions are validated without parameter adjustments against datasets from lab-scale and from pilot-scale coal furnaces at 1 and 29 MWt. Collectively, the evaluations cover 16 coals representing ranks from sub-bituminous through high-volatile bituminous, including cases with Cl2 and CaCl2 injection. The predictions are, therefore, validated over virtually the entire domain of Cl-species concentrations and UBC levels of commercial interest. Additional predictions identify the most important operating conditions in the furnace and gas cleaning system, including stoichiometric ratio, NO(X), LOI, and residence time, as well as the most important coal properties, including coal-Cl.     

Assessing sorbents for mercury control in coal-combustion flue gas

Sorbent injection for Hg control is one of the most promising technologies for reducing Hg emissions from power-generation facilities, particularly units that do not require wet scrubbers for SO2 control. Since 1992, EPRI has been assessing the performance of Hg sorbents in pilot-scale systems installed at full-scale facilities. The initial tests were conducted on a 5,000-acfm (142-m3/min) pilot baghouse. Screening potential sorbents at this scale required substantial resources for installation and operation and did not provide an opportunity to characterize sorbents over a wide temperature range. Data collected in the laboratory and in field tests indicate that sorbents are affected by flue gas composition and temperature. Tests carried out in actual flue gas at a number of power plants also have shown that sorbent performance can be site-specific. In addition, data collected at a field site often are different from data collected