基于正交实验的颗粒移动床烟气脱硫工艺参数优化

石灰石颗粒移动床脱硫工艺参数是影响脱硫效率和操作压降变化的重要因素,考虑到工艺参数对脱硫过程的影响,基于正交实验方法,通过直观分析和方差分析得到喷淋密度、空床气速、SO2浓度、烟气温度和床层下移速度对脱硫效率影响程度的主次顺序和脱硫效率与各因素之间的关系,并且分析了各因素对脱硫效率的影响规律。研究发现,各因素对脱硫效率的影响程度依次是空床气速>喷淋密度>SO2浓度>烟气温度>床层下移速度。喷淋密度对脱硫效率的影响高度显著,呈正相关;空床气速对脱硫效率的影响高度显著,呈负相关;SO2浓度和烟气温度对脱硫效率有影响但不显著,呈负相关。床层下移速度与脱硫效率呈正相关。     

新型颗粒层过滤性能的宏观数学模型

根据固定床颗粒层内气流含尘浓度的连续方程、颗粒层过滤规律和新型颗粒层的过滤特点,建立了固定床颗粒层过滤过程和新型颗粒层过滤性能的宏观数学模型;根据颗粒层的过滤机理和实际灰尘颗粒粒径的分布状态,在实验的基础上,修正了过滤速度对颗粒层过滤效率的影响;根据实验结果对过滤效率方程式、床层压降方程式中的特征参数进行了回归,得到了具体过滤介质的颗粒层宏观过滤数学模型。模型表明新型颗粒层过滤过程是一个不随过滤时间变化的准稳态过程,只与过滤介质特性和循环清灰周期有关,模型计算值能准确地反映颗粒层的过滤性能。     

扩散荷电作用下线板式ESP中PM2.5捕集效率的数值模拟

为考察线板式静电除尘器中PM2.5颗粒的除尘性能,建立电场、颗粒动力场和流场多场耦合下的数学理论模型.采用GAMBIT软件构造ESP实体结构,将用户自定义程序UDF导入到FLUENT软件中进行数值仿真,并应用DeutsehAnderson公式计算粉尘在不同荷电机理和2种不同除尘操作参数下的除尘效率.数值结果表明,扩散荷电效应对PM2.5分级除尘效率贡献率随粒径增大非线性减小;外加工作电压越低或烟道气流速越高,扩散荷电效应对PM2.5粉尘颗粒的影响越大;在较高外加电压工况下,扩散荷电对综合效率的影响与降低一定量的烟道气流速相当.     

多孔介质过滤细颗粒

以活性炭为过滤介质,利用其多孔结构脱除细颗粒,实现低压降除尘工艺。研究活性炭颗粒粒径、滤层厚度以及表观过滤风速等条件对多孔介质过滤细颗粒效果的影响,并通过表面光滑的不锈钢珠进行实验作对比,分析多孔介质过滤细颗粒的机理。结果表明:活性炭颗粒对细颗粒的过滤效率明显高于表面光滑的不锈钢珠。过滤效率随活性炭颗粒粒径和表观过滤风速的减小而增加,当粒径从1.5 mm降至0.45 mm时,平均过滤率从53.17%升至80.34%,当表观风速从26.54 cm·s~(-1)降到1.66 cm·s~(-1)时,平均过滤率从41.89%升至75.24%。过滤效率随滤层厚度的增加明显增加,当层厚从60 mm增加到140 mm时,过滤效率从47.62%增大到70.78%。不同实验条件下,过滤压降都没有随时间有明显变化,细颗粒没有在活性炭颗粒表层形成粉尘层。活性炭颗粒床主要是依靠细颗粒扩散、惯性碰撞和拦截效应沉积在活性炭多孔结构内,从而脱除细颗粒。     

YA-Ⅱ型沸腾颗粒层除尘器在冲天炉除尘上的应用

YA-Ⅱ型沸腾颗粒层除尘器,1982年获国家科委三等发明奖。该除尘器的主要优点是:能经济、高效地处理高温(370℃以下)含尘烟气。其次,维护保养简单、方便。除尘后其烟尘排放浓度为45mg/M~3,除尘效率为99.1％。由于这套除尘系统中没有采用烟气冷却设备,故该系统投资较低,占地面积小。     

颗粒层非稳态过滤捕集效率的研究

为计算颗粒层非稳态过滤效率,通过改进经典过滤理论模型,考虑颗粒在过滤介质中的沉积,理论推导得出非稳态过滤效率的计算公式,而经典颗粒层过滤效率计算公式仅为此计算公式的特例。因为理论计算公式是隐函数,不便于工程实际应用,所以,在常温条件下,对非稳态过滤时的过滤时间、过滤风速、过滤层厚度、粉尘浓度和颗粒层滤料均粒径等五个因素进行了正交实验研究。采用多元回归的方法得出各影响因素与过滤效率呈显性关系的效率关联计算公式,其计算结果与实验测试结果基本吻合。     

活性炭固定床操作参数的优化

研究了操作参数对活性炭固定床处理有机废气的影响。温度升高，吸附容量下降。湿度的存在会减少活性炭对有机物的吸附容量。适当的操作气速为0.1-0.5m/s，在此范围内，气速与压降在对数坐标上呈线性关系。     

收尘区脉冲供电对电除尘器收集性能的影响

建立了双区电除尘器实验模型,研究了预荷电压、不同供电方式下极板间距、电极型式对双区电除尘器收尘效果的影响.结果表明:随着预荷电压逐渐升高,除尘效率也随之增加,双区除尘效果明显优于单区的除尘效果.脉冲供电对电除尘器的除尘性能影响明显,与直流供电相比,脉冲供电对PM25的分级效率可提高16.9%;在较高的电压时,极板间距为...     

不锈钢烧结纤维毡外加粉体助剂过滤烟尘微粒

为了解决不锈钢烧结纤维毡对柴油机微粒过滤效率不高及其黏附堵塞问题,提出了不锈钢烧结纤维毡外加粉体助剂过滤烟尘的新方法。用不同过滤精度(5～30μm)的不锈钢烧结纤维毡片,覆盖不同厚度(0.5～3 mm)的粉体层,对由发烟剂燃烧产生的烟尘(D50=0.183μm)进行了过滤实验,用welas3000气溶胶粒径谱仪测试过滤前后的烟尘浓度,得到了不同情况下的过滤效率及分级效率。实验结果表明,粉体粒径、厚度、过滤气速及时间对过滤效率影响都很大,在滤速3 m/min、粉体粒径200～250目及厚度1.5 mm时,初始过滤效率高达95.746%,30 min后过滤效率上升到98.499%,300min内过滤效率基本保持在98%以上。     

直筒式旋风脉冲静电除尘器性能研究

实验研究了电压、入口粉尘浓度和入口风速对直筒式旋风脉冲静电除尘器除尘效率的影响,测定了在不同入口风速下除尘器的分级效率.结果表明,脉冲供电能显著提高除尘器的除尘效率和分级效率,在脉冲电压为80 kV、入口粉尘质量浓度为5.0 g/m3N、入口风速为7～10 m/s时,除尘效率在99%以上,并在实验的基础上分析了脉冲供电下除尘器的除尘机理.     

Dust collection efficiency analysis in a two-dimensional circulating granular bed filter

Dust collection efficiency data were analyzed to determine better operating conditions for a two-dimensional circulating granular bed filter (CGBF). The dust collection efficiency in the granular bed was affected by the following operating parameters: the louver angle, the solids mass flow rate, and the particle size of the bed material. Experimental results showed that higher dust collection efficiency occurs when the solids mass flow rates were 20.34 +/- 0.24, 21.50 +/- 0.11, and 30.51 +/- 0.57 g/sec at louver angles of 45 degrees, 30 degrees, and 20 degrees, respectively. Optimal dust collection efficiency peaked with a louver angle of 30 degrees. Average particle sizes of bed material by sieve diameters (microm) of 795 microm had higher dust collection efficiency than the average collector particle size of 1500 microm. Dust collection efficiency is influenced by bed material attrition phenomenon, causing dust collection efficiency to decrease rapidly. The dust collection efficiency analysis not only found the system free of design defects but also assisted in the operation of the two-dimensional CGBF system.     

Dust Collection Efficiency Analysis in a Two-Dimensional Circulating Granular Bed Filter

Abstract

Dust collection efficiency data were analyzed to determine better operating conditions for a two-dimensional circulating granular bed filter (CGBF). The dust collection efficiency in the granular bed was affected by the following operating parameters: the louver angle, the solids mass flow rate, and the particle size of the bed material. Experimental results showed that higher dust collection efficiency occurs when the solids mass flow rates were 20.34 ± 0.24, 21.50 ± 0.11, and 30.51 ± 0.57 g/sec at louver angles of 45°, 30°, and 20°, respectively. Optimal dust collection efficiency peaked with a louver angle of 30°. Average particle sizes of bed material by sieve diameters (μm) of 795 μm had higher dust collection efficiency than the average collector particle size of 1500 μm. Dust collection efficiency is influenced by bed material attrition phenomenon, causing dust collection efficiency to decrease rapidly. The dust collection efficiency analysis not only found the system free of design defects but also assisted in the operation of the two-dimensional CGBF system.     

Fine dust filtration using a metal fiber bed

A bed-type filter composed of thin metal alloy fiber was closely examined with dust capturing in cold and hot runs. The investigation of an individual mechanism across the filter bed indicated that the aerated dust could be initially collected by depth filtration, and after a while, surface filtration dominated the overall dust collection. The present metal fiber bed was comparable to the conventional ceramic filters because of its good collection efficiency with low pressure drop. It also showed potential to be used as a prefilter in a diesel exhaust trapping system.     

Fine Dust Filtration Using a Metal Fiber Bed

Abstract

A bed-type filter composed of thin metal alloy fiber was closely examined with dust capturing in cold and hot runs. The investigation of an individual mechanism across the filter bed indicated that the aerated dust could be initially collected by depth filtration, and after a while, surface filtration dominated the overall dust collection. The present metal fiber bed was comparable to the conventional ceramic filters because of its good collection efficiency with low pressure drop. It also showed potential to be used as a prefilter in a diesel exhaust trapping system.     

滤料负载粉尘层对气态汞脱除性能的实验研究

通过不同性能纤维滤料负载燃煤飞灰粉尘层,来模拟袋式除尘器滤袋表面粉尘附着层,进而研究袋滤器用不同性能纤维滤料和粉尘附着层对燃煤烟气中Hg0的联合脱除性能。在固定床实验系统上分别进行了不同纤维滤料和燃煤飞灰粉尘层,以及经实验优选得到的华博特滤料负载燃煤飞灰粉尘层脱除燃煤烟气中Hg0的实验研究。结果表明,燃煤飞灰粉尘层和华博特滤料对Hg0分别有一定的脱除作用,脱除效率可达35%和42.5%,它们对Hg0的脱除是物理吸附和化学吸附共同作用的结果;同时,华博特滤料负载燃煤飞灰粉尘层对Hg0的联合脱除效率受到吸附反应温度、入口汞浓度和烟气停留时间等因素的影响,最佳脱汞率可达64.4%;吸附反应温度越高,脱除效率越低;烟气停留时间越大,脱除效率越高;入口汞浓度的提高并不一定提高华博特滤料负载飞灰粉尘层的脱汞效果。     

Panel Bed Filters for Simultaneous Removal of Fly Ash and Sulfur Dioxide:

Experimental studies of the filtration of dilute aerosols of Dow microspheres by beds of sand have been conducted with flows passing vertically upward, vertically downward, and horizontally. With the use of Happel’s “free surface” model for a granular bed, the results can be correlated reasonably well by semiempirical, semitheoretical considerations taking into account collection by diffusion, gravity settling, direct interception, and inertial impaction. The results are preliminary to experiments to be made on filtration of aerosols by a filter cake of fly ash resting upon a sand bed.     

Feasibility of granular bed filtration of an aerosol of ultrafine metallic particles including a pressure drop regeneration system

A process for filtering an aerosol of ultrafine metallic particles (UFP) has been designed and tested, based on the principle of a multistage granular bed. The filtration system comprised a succession of granular beds of varying thickness composed of glass beads of different diameters. This system allows the pressure drop to be regenerated during filtration (“on-line” mode) using a vibrating probe. Tests monitoring the pressure drop were conducted on a “10-L/min” low airflow rate device and on a “100-m³/hr” prototype. Granular bed unclogging is automated on the latter. The cyclic operation and filtration performances are similar to that of filter medium-based industrial dust collectors.

Implications:?Filtration of ultrafine metallic particles generated by different industrial processes such as arc welding, metal cutting, or spraying constitutes a difficult problem due to the high filter clogging properties of these particles and to the high temperatures generally encountered. Granular beds represent an advantageous means of filtering these aerosols with difficult properties.     

颗粒层过滤压力损失的实验研究

为减小颗粒层过滤器过滤压力损失及降低运行费用,探寻颗粒层过滤压力损失的变化规律及减低其压力损失的途径,合理地确定清灰周期,通过建立颗粒层实验装置,在稳态过滤及非稳态过滤2种条件下,进行过滤压力损失的单因素及正交实验研究,得出了过滤风速、过滤入口粉尘浓度及过滤时间对颗粒层过滤器压力损失的影响规律。通过回归分析得出了颗粒层过滤器压力损失在稳态过滤及非稳态过滤过程的关联计算式及计算式的适用范围,关联计算式计算结果与相关文献对比结果基本吻合。