基于小波优化EEMD的二氧化硫检测

为解决检测SO₂时系统接收到的荧光信号微弱、易被噪声淹没的问题,提出了小波优化总体经验模态分解(EEMD)的方法对SO₂荧光信号进行去噪。搭建了SO₂紫外荧光检测系统对SO₂浓度进行检测,检测的平均相对误差为0.0011, SO2浓度与荧光强度的线性相关系数为0.9787。利用小波优化EEMD去噪方法对SO₂荧光信号去噪,得到的信噪比为224.7958,均方误差为1.01×10^-7,波形相似系数为0.9973,SO2浓度与荧光强度的线性相关系数为0.9936。相比于EEMD和小波去噪方法,小波优化的EEMD去噪方法对SO2荧光信号的去噪效果更好,能够达到理想的去噪效果。     

浅析火力发电厂超低排放中SO2的测量

在火力发电厂超低排放海水脱硫系统中,烟气中含湿量大、SO₂浓度低,由于SO₂易溶入水,因此导致其测量较为困难。而采样管内积水会造成SO₂测值偏低。该文针对异常原因分析并对采样管进行改善,以解决因积水问题造成的测值异常。稀释探头限流孔堵塞会导致SO₂测值异常,该文分析了造成限流孔易堵塞原因,改善了探头加热系统,保证了SO₂的准确测量。采用OPSIS公司稀释采样法和API公司T100型紫外荧光法SO₂分析仪能准确稳定地测量烟气中SO₂浓度,满足现行环保法规的要求。     

改性沉珠对吸附脱除SO2效率的影响

SO₂是目前危害最大的大气污染源之一，为控制SO₂的超标排放，我国展开了多种脱硫剂的研究。其中粉煤灰经改性后脱硫效果得到大幅度提升。沉珠是可从粉煤灰中分选而来的一种特殊的微珠，不仅化学组分与粉煤灰基本相似，而且具有比常规粉煤灰更强的“火山灰活性”。为了探究改性沉珠对吸附脱除SO₂效率的影响，对比分析改性前后沉珠的矿物组成、颗粒形貌等，并在模拟干法烟气脱硫实验平台上，实验研究改性沉珠与传统Ca(OH)₂脱硫剂吸附脱除SO₂的效率。结果表明：改性沉珠比原状沉珠的比表面积更大，孔隙更多，有利于提升吸附脱除烟气中SO₂的效率；沉珠改性后生成水合硅酸钙、水合铝酸钙、水合硅铝酸钙等产物；对比分析Ca(OH)₂与改性沉珠的脱硫效率，Ca(OH)₂的脱硫效率随时间推移明显降低，最高脱硫率为93.5%,而改性沉珠的脱硫效率稳定，最高脱硫率高达100%且持续80 min,脱硫效果明显远优于Ca(OH)₂。     

紫外吸收光谱法在线测量SO3的实验研究

基于紫外吸收光谱法对SO₃的在线测量进行了实验研究,搭建了SO3气体发生系统。为提高检测精度,探究了去除测量过程中的各种干扰因素。SO₃与SO₂的特征吸收波段重叠严重,通过合理选择特征吸收波段和光谱反演策略最大程度地去除SO₂对SO₃测量的影响。研究中采用标准曲线法结合单波长法、双波长法和积分光谱法建立了标准曲线。结果表明:积分光谱法的测量误差最小,可优先应用于SO3排放的在线光谱计量分析。     

湿法烟气脱硫塔能效特性研究

针对湿法烟气脱硫能效规律欠缺问题,以150 MW超低排放机组湿法脱硫塔为研究对象,基于脱硫设备的主要能耗和脱硫效率构建了脱硫能效指标——脱硫能效值,并采用数值模拟和理论分析相结合的方法,探究了液气比、入口烟气量、烟气流速、入口SO₂质量浓度、烟气温度等参数以及不同喷淋层组合方式对脱硫能效特性的影响规律。结果表明：脱硫能效值为0.22~0.96 kg/（kW·h）,并随入口SO₂质量浓度增加呈正比例变化,随喷淋层组合数、液气比和入口烟气温度增加呈反比例变化,随入口烟气量和塔内烟气流速增加先上升后下降。研究结果可为脱硫技术评价和脱硫系统节能运行提供参考。     

燃煤电厂超低排放湿法脱硫治霾影响分析

根据燃煤电厂湿法脱硫出口污染物排放浓度及其排放绩效,分析了超低排放湿法脱硫的治霾效果,阐明了湿法脱硫有利于减少SO₂、颗粒物、SO₃的排放量,这些污染物都是形成雾霾的前体物,表明超低排放湿法脱硫对雾霾治理有积极的贡献。同时,烟气超低排放具有协同治理有色烟羽的能力,对于有色烟羽治理应采取因地制宜的策略。煤电行业广泛开展烟气超低排放改造后,大气污染物排放量持续减少,空气环境质量逐年改善,湿法脱硫、烟气超低排放功不可没。     

基于Na3Zr2Si2PO12固体电解质的非平衡态SO2传感器

基于Na₃Zr₂Si₂PO₁₂(NASICON)固体电解质, 分别以Na₂SO₄-BaSO₄混合盐和NaRe(SO₄)₂复盐为敏感电极材料制备了片式SO₂非平衡态气体传感器。结果表明, 该类型传感器的输出电动势与SO₂气体浓度的对数呈良好的线性关系, 在低温260℃具有最佳性能, 灵敏度分别达到了160 mV/decade和136 mV/decade。传感器在不同浓度的SO₂气体中的交流阻抗谱测试结果显示, 气体在敏感电极的三相界面处电化学反应的活性随着气体浓度的增大而增强, 结合敏感电极结构, 对该类敏感电极的机理进行了分析。由于NASICON具有良好的低温钠离子导电性, 可以大幅降低传感器的工作温度; 由于Na₂SO₄-BaSO₄混合盐和NaRe(SO₄)₂敏感材料具有更好的化学稳定性, 制备的传感器具有良好的可重复性和稳定性。基于非平衡态设计的传感器, 具有结构简单和成本低的优点。以上特性为该传感器在SO₂气体在环境监测方面的应用提供了可能。     

基于变量选择的电站燃煤锅炉NO_(x)排放浓度预估北大核心CSCD

针对电站燃煤锅炉NOx排放浓度存在测量迟延的情况,提出了基于互信息和长短期记忆神经网络相结合的电站燃煤锅炉NO_(x)排放浓度预测模型。首先,利用互信息计算出候选输入变量与输出变量NO_(x)浓度之间的延迟时间,并引入最大相关最小冗余算法,筛选出最优特征子集,将最优特征子集作为LSTM模型的输入,建立了锅炉NO_(x)排放浓度预测模型。仿真结果表明,所建模型的测试集均方根误差为4.626 mg/m^(3),平均绝对误差为3.836 mg/m^(3),与未经变量选择和未考虑时延的LSTM模型相比,预测精度显著提高。     

基于MPA-SVM的煤矿抛掷爆破爆堆形态预测

为提高爆堆形态预测精度，提出了一种海洋捕食者算法（MPA）优化支持向量机（SVM）的方法，结合黑岱沟露天煤矿爆破工程数据，选取其中8个参数作为影响爆堆形态的输入参数，松散系数ξ和Weibull函数的2个控制变量α、β为输出参数，建立基于MPA-SVM的爆堆形态预测模型，并与同期使用的5个模型进行比较。结果表明:MPA-SVM的预测效果优于其他5个模型，相对误差未超过5%，3个评价指标分别为R₂（0.955,0.978,0.946），R_MSE（0.063,0.075,0.116），R_MAE（0.046,0.056,0.067），证明了MPA-SVM对爆堆形态预测的适用性，且在小样本数据条件下更具有精度优势。     

气态元素汞校准的一致性光学评定检测实验研究

利用低压汞灯作为光源,结合单色仪,对汞渗透管法和汞饱和蒸气法气态元素汞校准进行一致性光学评定检测研究。在汞渗透管实验中,吸收度面积值与理论浓度的皮尔逊相关系数为0.996 8,拟合优度为0.993 6,说明两组数据相关性较好且符合郎伯比尔定律。取实验的吸收截面作为标准参考吸收截面,对相同浓度汞蒸气横向对比及不同浓度汞蒸气纵向对比,浓度误差最大为7.45%,表明渗透管法的稳定性较好且精度较高,验证了渗透管法作为汞标气法的可行性。在渗透管实验中加入SO₂,气态汞浓度测量误差最大为12.82%,说明SO₂对汞吸收度测量产生一定程度的干扰。汞饱和蒸气法实验中,以渗透管为基准测得的最大误差在标准允许误差之内,表明2种校准方法具有一致性。但汞饱和蒸气法与渗透管法相比,其重复性及精度仍有不足,待提升空间较大。     

SO2 SCRUBBING BY ULTRAFINE CA(OH)2 AEROSOL

The objective of the present study was to generate submicrometer calcium hydroxide aerosols and to investigate the effectiveness of such aerosols in sulfur capture. The effectiveness of SO₂ removal by Ca(OH)₂ aerosol has been investigated in an isothermal reactor. Ca(OH) ₂ aerosol was generated by a novel fluidizer system in which submicrometer-sized powders were entrained in gases. SO₂ was added to this aerosol to a concentration of 2000 ppm. The aerosol-SO₂ mixture was heated to 550°C-750°C in an isothermal tube reactor. The SO₂ removal efficiency, which varied from 20% to 70%, was determined to be a function of the aerosol concentration, reactor temperature and residence time. The fraction of aerosol reacted was not affected strongly by the aerosol concentration. The reaction kinetics were determined from the experimental data using a simple analytical model in which the rate is first order in both SO₂ and calcium hydroxide aerosol concentrations.     

MASS TRANSFER OF SULFUR DIOXIDE TO CONDENSING AQUEOUS AEROSOLS

Sodium chloride aerosols were generated from a 1.0 percent solution and passed through a tubular furnace, then recondensed at 29°C in a cooling section in the presence of SO₂. The dry particles ranged from 0.711 to 0.843 µm and the condensed droplets were in the 1.66 to 2.88 µm range. Final droplet size was varied by controlling the temperature of the nebulizer solution between 17 and 50°C. The SO₂ concentration in the gas phase of the condensing cloud was varied between 0.5x10 - ³ and 2.5 xl0 - ³ atm.

Cloud droplets were separated from the gas stream in a point-to-plane electrostatic precipitator and the droplets analyzed colorimetrically for total sulfur content.

Concentrations of SO₂ in the aqueous phase were about one order of magnitude greater than values obtained from equilibrium constants. The collection rate of SO₂ at 29°C appeared to be first order in SO₂ gas phase concentrations.

A model for this process was constructed, based on the hydrate formation in the gas-water interface[SO₂]_g + n[H₂O]ℓ ⇋ [SO₂ · n(H₂O)]ℓ

The order of the hydrate n was estimated to be 4.0.     

磺酸基改性二维Ti3C2Tx纳米材料制备与Pb2+吸附性能

对二维Ti₃C₂T_x材料进行了磺酸基团接枝改性(Ti₃C₂T_x—SO₃H),表征了改性前后微观结构的变化,研究了对重金属Pb2+的吸附行为与机制。XRD、FTIR及EDS表明磺酸基团在Ti₃C₂T_x表面成功接枝,而SEM则发现Ti₃C₂T_x?SO₃H呈现较Ti₃C₂T_x更轻薄的层状结构。改性后,Ti₃C₂T_x—SO₃H对重金属Pb2+20 min内达到吸附平衡,最大吸附量达到733.6 mg·g?1,较Ti₃C₂T_x吸附量提升了23%,且吸附量随着pH(2~6)的增加而逐渐增大,在Mg2+、Ca2+、Co2+、Zn2+等共存离子的干扰下,仍保持较高的吸附水平。机制分析表明,改性前后吸附过程均符合准二级动力学模型和Langmuir吸附等温线拟合模型,以单分子层化学吸附为主,但由于磺酸基团提供了更多的吸附饱和活性位点,并提高了Ti₃C₂T_x在水溶液中的分散性,使改性后对Pb2+吸附性能更优异。      

Carbon-enriched coal fly ash as a precursor of activated carbons for SO2 removal

Carbon-enriched coal fly ash was evaluated in this work as a low-cost adsorbent for SO₂ removal from stack gases. The unburned carbon in coal fly ash was concentrated by mechanical sieving and vegetal oil agglomeration. The carbon concentrates were activated with steam at 900 °C in order to develop porosity onto the samples. The performance of these samples in the SO₂ abatement was tested in the following conditions: 100 °C, 1000 ppmv SO₂, 5% O₂, 6% water vapor. A good SO₂ removal capacity was shown by some of the studied samples that can be related to their textural properties. Cycles of SO₂ adsorption/regeneration were carried out in order to evaluate the possibility of thermal regeneration and re-use of these carbons. Regeneration of the exhausted carbons was carried out at 400 °C of temperature and a flow of 25 ml/min of Ar. After each cycle, the SO₂ removal capacity of the sample decreases.