Experimental study of the dust-removal performance of a wet scrubber

A variety of dust control methods are often applied in coal mines,among which the application of wet scrubbers has proven to be an efficient technology for the removal of dust in airstreams,rather than diluting or confining the dust.In this paper,a wet scrubber design was developed.Based on a self-designed experimental test platform,the total dust concentration,respirable dust concentration,air volume,and average pressure drops of wet scrubbers with 12,16,20,and 24 blades were measured under different water intake conditions.The results show that the different water intake levels have only minimal effects on the air volume of the wet scrubbers.However,increased water intake had improved the dust removal efficiency of the wet scrubbers with the same number of blades.The wet scrubber with 16 blades was found to have the best dust removal efficiency at a water intake level of 1.35 m^(3)/h.Its total dust and respirable dust removal efficiency reached 96.81%and 95.59%,respectively.The air volume was 200.4 m^(3)/min,and the average pressure drop was determined to be 169.4 Pa.In addition,when the wet scrubber with 16 blades was applied in a coal preparation plant in China's Shanxi Province,it was observed that the total dust concentration had fallen below 8.1 mg/m^(3),and the respirable dust concentration had fallen below 5.9 mg/m^(3).Therefore,the results obtained in this research investigation provide important references for the use of wet scrubbers to improve coal production environmental conditions.

Research on the application of the wet scrubber on the BSSF slag processing system at Baosteel

Based on the analysis results of the dust size distribution of flue gas from Baosteel＇s short-flow （BSSF） slag processing system and the mechanism of the wet scrubber,a wet scrubber system was designed and installed in the No. 1 BSSF slag processing system at Baosteel. The results show that the dust removal efficiency of the previous system that had conventional water nozzles was only 69% with a liquid-gas ratio of 0.79 L/m^3 ,while the dust removal efficiency reached 94% when three sets of high-efficiency dual phase spray guns were installed inside both the flue and the chimney. For the latter system,the liquid-gas ratio was 0. 84 L/m^3 ,and the dust concentration in the cleaned emissions reduced to less than 40 mg/m^3.

Hydrodynamics of the Pilot Scale Wet Scrubber with Restricted Outlet Absorbent Flow Rate

This paper presents the hydrodynamics of the wet scrubber coupled to a pilot CFB incineration facility. The scrubber was operated using tap water as a scrubbing liquid. The outlet liquid flow rate, Qo, and accumulation rate, Qa, strongly depend on the inlet liquid flow rate, Qin, with different profiles. At higher Qin values, Qo stabilizes, leading to higher Qa and finally flooding. The values of Qa were higher than Qo except for Qin ranging between 0.53 and 0.72 L/s (safe operating range) in which Qa ≌ Qo and Qa = Qin/2. The outlet-to-inlet liquid flow rate ratio, Qo/Qin decreased for Qin > 0.53 L/s. The increase in the accumulation-to-inlet liquid flow rate ratio, Qa/Qin, at higher Qin indicates a change in flow regime towards flooding, accompanied by an abrupt increase in the height of accumulating liquid, Ha. The difference between Qa/Qin and Qo/Qin (denoted as, ΔQao/Qin), shows a minimum close to zero in the safe operating range. The gas flow rate towards the wet scrubber had slight effect on Qo and Qa when Qin was maintained constant. The ratio Qo/Qin decreased slightly with Ha/Ht irrespective of gas velocity. Changing the liquid-to-gas ratio, L/G and Qin strongly affects the maximum and minimum values of Qo/Qin and Qa/Qin.

Removing ammonia from air with a constant pH, slightly acidic water spray wet scrubber using recycled scrubbing solution

Previous research on wet scrubbers has only studied highly acidic scrubbing solutions because of their high ammonia capture efficiencies; however, the high acidity created practical problems. Lower acidity solutions would reduce corrosion, maintenance, and cost; however, designers may need to use strategies for increasing scrubber effectiveness, such as using lower air velocities. The objective of this studywas to determine if a spray scrubber with slightly acidic and higher p H scrubbing solution （pH from 2 to 8） could effectively remove NH3 from NH3 laden air （such as animal building exhaust air）, and also collect this valuable resource for rater use as a fertilizer. A bench-scale spray wet scrubber treated 20 ppmv NH3/air mixture in a countercurrent contact chamber. First, the solution pH was varied from 2 to 8while maintaining constant air velocity at 1.3 m. s-1. Next, air velocity was increased （2and 3 m.s-1） while solution pH remained constant at pH6. At 1.3 m.s -1, NH3 removal efficiencies ranged between 49.0% （pH8） and 84.3% （pH2）. This study has shown that slightly acidic scrubbing solutions are a practical means of removing ammonia from air especially if the scrubber is designed to increase collisions between solution droplets and NH3 molecules. The NH3 removed from the air was held in solution as NH4＋ and accumulates over time so the solution should be an excellent fertilizer.

Experimental study on performance of flow & desulfurisation of a gas-liquid screen scrubber for wet flue gas desulfurization

In the paper, the gas-liquid two-phase flow performance and desulfurisation performance of the gas-liquid screen scrubber were experimentally studied when limestone was used as absorbent. Experiments were carried out at varying the flue gas velocity and slurry flux in concurrent and countercurrent tower respectively. The experimental results showed that the flow resistance of absorber increased rapidly with an increase of the flue gas velocity whether in concurrent or in countercurrent tower, and the up trend of the flow resistance in the countercurrent tower was higher than those in the concurrent one. The influence of the flue gas velocity on the flow resistance of absorber was more than those of the slurry flux density. Whether in the concurrent tower or in the countercurrent one, increasing the flue gas velocity or the slurry flux density would enhance the desulphurization efficiency. The influence of the slurry flux density on the desulfurisation efficiency was greater than those of the flue gas velocity.

Assessment of NH3 Reduction and N2O Production during Treatment of Exhausted Air from Fattening Pigs Building by a Commercial Scrubber

The use of air scrubbers to reduce ammonia (NH3) emissions from buildings on pig farms is one of the most promising techniques in the GÖteborg protocol and other European regulations including the Industrial Emission Directive. In France, some air scrubbers are currently used on pig farms, mainly to reduce odours from livestock buildings. However, recent research revealed the production of N2O resulting from the treatment of air from pig buildings. In this context, a two-month study was conducted on a pig farm with 750 places for fattening pigs to check the abatement of NH3 emissions and to assess the possible production of N2O during treatment of exhausted air from buildings housing fattening pigs by a air scrubber. Concentrations of NH3 and N2O in the inlet and outlet air of the scrubber were continuously monitored using an Innova 1412 infrared analyzer. With the scrubber operating parameters (airflow, design, size), our results confirmed the production of N2O in the order of 5% of NH3-N reduced. N2O was produced by biological nitrification and/or denitrification inside the air scrubber. Statistical analysis (Pearson’s test) showed that the production of N2O was strongly influenced by the rate of airflow and the outside temperature. The abatement of NH3 emissions from the building was only 33%, i.e. much lower than the 70% - 90% usually cited in the literature.

High Efficiency Dust Scrubbers for Continuous Miner in Underground Mines

Based on the experimental data by a full scale test model and the relevant existing achievements, four new concepts of group dust scrubbers were designed in the paper. The new dust scrubbers consist of two to four common dust separators in series: wet fan, wet Venturi and foam filter bed. Wetting and foaming agents are used to increase the efficiency of dust separation. High efficiency is not required for each part of the group dust scrubbers, but the whole system has a high working reliability. All parts of the group dust scrubbers have the most suitable separating efficiency for different size and concentration of dust particles in airflow, according to their technical features. Four group dust scrubbers have a high efficiency from 94.4% to 99.7% for separating respirable dust at a rational cost.

聚氯乙烯干燥尾气干法和湿法除尘技术的比较与应用

论述了聚氯乙烯干燥尾气的深度处理技术——干法袋式除尘器和湿法文丘里洗涤器的工作原理和主要设备,这两种技术成功应用于国内多家厂商,排放的干燥尾气含尘质量浓度<10mg/m^(3),满足国家和地方有关特别排放限值的标准。

凝结洗涤塔脱除燃煤超细颗粒实验研究

对洗涤塔内相变促进燃煤细颗粒凝结长大与脱除进行了实验研究。通过在洗涤塔入口和洗涤塔内注入适量蒸汽,使其在塔内不同区域形成细颗粒凝结长大所需的过饱和环境。探讨了2种情况下,不同操作参数对燃煤超细颗粒脱除效率的影响规律。结果表明2种蒸汽添加方式均可显著促进燃煤超细颗粒的脱除,蒸汽添加量为0.03kg/m3时,颗粒数浓度脱除效率分别提高了50%和60%;对于塔前添加蒸汽,气液温差的提高有利于细颗粒的脱除,而塔内添加蒸汽则正好相反;此外,对于气液温差较大的情况,增大液气比可有效提高脱除效率;燃煤细颗粒的脱除效率随烟气在塔内停留时间的增加而提高,特别是塔内添加蒸汽的情况,当停留时间为1.5s时,塔前和塔内添加蒸汽脱除效率可分别达到60%和65%以上,而未添加蒸汽时脱除效率几乎不受停留时间的影响。

旋转填充床除尘技术的研究

采用新型传质分离设备———旋转填充床研究其对发电厂燃煤飞灰的除尘性能。作为一种湿式除尘器 ,在气量 2 0 0m3 /h ,液量 0 5～ 2 0m3 /h ,转速 90 0～ 1 5 0 0r/min的条件下 ,旋转填充床显示出良好的颗粒捕集性能 ,总效率达 99%以上 ,切割粒径范围在 0 0 2～ 0 3μm ,设备的气体压降较低。讨论了旋转填充床的除尘性能和压降行为 。

湿式除尘器除尘机理的理论分析

对湿式除尘机理进行了理论分析，导出了湿式除尘器分级效率的计算公式．结果表明，影响湿式除尘器分级效率的主要因素是液气比和气液混合物的速度，为设计和研制高效湿式除尘器提供了理论依据．

湿法烟气脱硫吸收塔仿真模型开发及应用

吸收塔作为石灰石/石膏湿法烟气脱硫系统的核心部件,关于其脱硫效率影响因素众多,动态特性非常复杂,一直难以通过化学反应动力学模型以及计算流体力学模型对其进行精确定量描述。文章首先引用典型相关分析理论,对吸收塔输入参数与输出参数两组变量之间的相关性进行统计分析,完成数据初步筛选;然后引用主成分分析方法,把多元变量间的相关性研究化为少数几对变量之间的相关性研究,最后以进口烟气流量、进口烟气温度、进口烟气SO2浓度、液气比、进口烟尘浓度、烟气流速、石膏浆液密度、石膏浆液pH值等参数为输入变量,运用多神经网络建模技术来完成吸收塔动态实时仿真模拟。太仓港环保电厂脱硫装置实际应用表明:该模型脱硫效率预测误差小于1%,吸收塔内出口压力预测误差小于50 Pa,完全满足工程应用精度。壤剖面多环芳烃主要来源于煤的高温不完全燃烧产物,兼有少量的石油污染贡献。这与武汉市以煤为主的复合型能源利用结构相符合。

湿式除尘器中脱水装置性能的理论和实验

详细分析了湿式除尘器中脱水装置的脱水机理，并对脱水装置性能进行了实验研究， 建立了脱水装置的极限风速和阻力系数与液气比有关的经验和半经验公式，为研究和设计其 他类型的脱水装置提供理论依据和实验数据．

多层喷雾洗涤塔对粉尘颗粒的脱除特性

通过搭建多层喷雾洗涤塔实验台,研究了液气体积比、塔内气体平均流速、粉尘浓度、喷雾压力等操作参数对除尘效率的影响规律。研究结果表明:洗涤塔内喷雾层数对除尘效率的影响最为显著,与传统的单层相比,除尘效率可以提高15%以上,并且入口粉尘浓度的变化对其除尘效率的影响较小。增大喷雾压力可以有效提升除尘效率,当喷雾压力为0.5~0.6MPa时除尘效率变化趋于稳定。在相同操作参数下,适当降低气体在塔内平均流速有利于提高洗涤塔的除尘效率,对于三层喷雾洗涤,最佳的气体塔内平均流速为0.6~0.8m/s。当喷雾压力为0.6MPa、塔内气体平均气速为0.6m/s、液气体积比为5.27的条件下,三层喷雾除尘的效率可以达到98.3%。

城市污水处理厂的恶臭污染控制技术

城市污水处理厂的恶臭污染已经引起越来越多的关注。文章介绍了城市污水处理厂恶臭气体的主要组成成分及其来源 ,对国外已有的湿式洗涤法、活性炭吸附法、臭氧处理法、焚烧法、生物洗涤法及掩蔽法等恶臭污染控制技术进行了介绍和工艺比较 。

静电增强湿式除尘器的优化运行

利用颗粒和液滴间的静电吸引力可以大幅度提高传统湿式重力喷淋除尘器的除尘性能。着重分析液滴荷电而颗粒不荷电的湿式除尘器的工作状况,阐述了布朗扩散、拦截、惯性碰撞和静电捕集等4种除尘机理。介绍了典型工况中该除尘器烟尘颗粒度分布,并通过分析捕集速率(沉积核)的方式对该除尘器的运行优化进行了分析。结果表明:含尘气流输运速度越大,液滴喷射速度越小;液滴几何尺度越小,液滴荷质比越高;液气比越大,越有利于可吸入颗粒物的高效脱除。

湿法除尘对垃圾焚烧炉中二恶英排放特性影响的试验研究

运用气相色谱/质谱联用机测定了150 t/d垃圾焚烧流化床锅炉不同工况下湿法除尘器前后烟气中二恶英(PCDD/Fs)的含量,不同工况下湿法除尘器脱除烟气中二恶英的效率分别为87.33%、99.53%、85.84%,排放到大气中的二恶英含量均小于国家规定的排放标准(1ngI-TEQ/Nm3),试验结果表明湿法除尘器是较为有效的脱除二恶英的装置。

综掘工作面粉尘运移规律及控制技术研究

针对煤矿综掘工作面现有粉尘治理措施存在的不足,在长压短抽通风除尘方式中利用附壁风筒的旋流控尘作用将高浓度粉尘聚集在迎头,同时结合新型气水喷雾模块进行综合粉尘防治;以淮南煤矿区某综掘工作面为原型,根据井下实际情况,利用Gambit建立掘进巷道的几何模型,并利用Fluent软件对不同条件下掘进巷道通风过程中粉尘分布情况进行数值模拟计算与分析,确定了综掘工作面高浓度粉尘分布和运移规律;综合以上情况,采用长压短轴通风方式下新型气水喷雾模块附壁风筒配合自激式水浴水膜除尘器治理综掘工作面粉尘,现场检测显示,在回风侧全尘及呼吸性粉尘除尘效率均达到了89%以上。

催化烟气湿法洗涤脱硫技术探讨

烟气湿法洗涤脱硫技术适合于催化烟气的脱硫净化处理。文章介绍了几种国外成熟工业化应用的催化烟气湿法洗涤脱硫技术和国内催化烟气洗涤、净化方面的研究现状,提出了国内开发催化烟气湿法洗涤脱硫技术应注意的问题,并对不回收硫资源、占地少、烟气压降小的催化烟气湿法洗涤脱硫技术及其工业化应用进行了初步的探讨。

新型矿用湿式除尘器的研究与动态模拟

结合综采工作面粉尘浓度分布和湿式除尘机理,对新型矿用湿式除尘器进行了介绍,该湿式除尘器具有体积小以及安装和维修方便等特点,能够除掉0.1μm以上的尘粒。重点对蜂窝扰流滤芯的设计、工作原理以及提高除尘效率的方法进行了分析,最后通过3DStudio Max软件动态模拟了湿式除尘器的工作过程,为除尘器的进一步优化提供理论依据。