共查询到19条相似文献,搜索用时 203 毫秒
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在固定床冷态实验装置上研究了平均粒径和稳态过滤压降相近、颗粒形状和表面状况不同的两种滤料(陶瓷球和石英砂)的过滤性能. 结果表明,两种滤料过滤性能变化规律基本一致. 粉尘沉积量(?m)增加,过滤效率先增大后减小,过滤压降偏离稳态过滤压降程度(G)增大. ?m相同时,过滤效率和G均随过滤气速增大而减小,但过滤后期高气速下G与低气速下接近. 增大入口粉尘浓度,总体过滤效率无明显改变,粒径大于0.7 ?m的粉尘过滤效率提高,G更显著. 两种滤料难过滤粉尘粒径均为0.35~0.6 μm. 因颗粒形状和表面状况不同,两种滤料过滤性能存在差异,其它条件相同时,石英砂总体和分级过滤效率均高于陶瓷球,G也较大;增大入口粉尘浓度,石英砂过滤效率随粉尘沉积量变化程度相对较小. 相似文献
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《化学工程与装备》2019,(11)
袋式除尘器是工业常用的高效除尘设备,滤料及滤料再生是其能稳定运行的关键。本实验搭建了可清洁式粉尘过滤特性测试系统,提出了以残余压降、压力上升速率和清灰周期来表征清灰效果,探究了不同喷吹时间和喷吹压力对清灰效果和过滤效率的影响。结果表明当喷吹压力Pb为0.5MPa,喷吹时间τ为0.2s时,第一个残余压降为360.1Pa,第一个清灰周期为400s,当τ增大到0.5s、0.8s时,对应的残余压降下降47.6%、51.3%,清灰周期提高75.0%、107.5%,且压力上升速率也相对应下降,说明喷吹时间变大清灰效果更好,但并不呈现线性变化。当提高喷吹压力时,也出现相似的变化规律。 相似文献
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滤袋寿命是袋除尘器主要考察指标之一。滤袋寿命不仅仅与滤料材质有关,更与除尘器使用条件,除尘器结构形式,工作机理等诸多因素有关。本文分别从进气方向、过滤风速、灌入速度、气流分布、滤料处理、气流扰动等方面进行了详细研究,提出了相应措施及对策。 相似文献
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为解决布袋除尘器在煤粉工业锅炉系统中滤料失效问题,针对2个煤粉工业锅炉系统布袋除尘器在使用一个采暖季后滤料破裂,除尘器失效的问题,通过常规性能测试、红外光谱分析、差热分析和电镜扫描等方法对失效滤袋进行分析。结果表明:滤料未采用适当材质和喷吹位置安装不当分别是造成2个滤袋失效的主要原因。从系统运行参数和设备安装方面分析,提出聚苯硫醚(PPS)材质滤料是煤粉工业锅炉系统除尘器滤料的最佳选择,喷吹管上的喷嘴与花板孔之间同心度是除尘器安装的关键,为今后工程中滤袋的选择和除尘器的安装提供了依据,从而保证了过滤效果,延长了滤袋的使用寿命,减少了不必要的损失,确保烟尘排放正常达标。 相似文献
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《煤炭转化》2019,(6)
为解决粉煤热解工艺中干馏气含尘量较大及颗粒床过滤器滤料再生问题,在颗粒床过滤器除尘实验装置上比较了半焦和石英砂两种滤料的过滤性能,分别采用单因素和正交实验法,考察了表观气速、滤料厚度、滤料粒径和粉尘进料浓度对颗粒床除尘性能的影响。结果表明:多孔介质半焦对粉尘的过滤效率明显高于石英砂;随着过滤时间的延长,除尘效率均呈现先增大后减小的趋势;从过滤质量因子角度考虑,当表观气速为0.35 m/s,滤料厚度为150 mm,滤料粒径为0.83 mm~1.25 mm时,颗粒床过滤器具有较高的过滤性能;粉尘进料浓度增加,在过滤前期除尘效率随之增大,但在过滤后期高进料浓度下除尘效率下降的速率较快。各因素对颗粒床过滤器最大除尘效率影响程度由大到小依次为:表观气速、滤料厚度、滤料粒径、粉尘进料浓度。当表观气速为0.25 m/s,粉尘进料浓度为10 g/m~3,床层厚度为150 mm,滤料粒径为0.38 mm~0.83 mm,除尘效率最大,为99.20%。 相似文献
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采用聚结型滤芯气液过滤性能实验装置,研究了油雾加载率和表观过滤速度对折叠滤芯过滤性能的影响及涂覆粘合剂对折叠滤芯过滤性能的优化作用。结果表明,涂覆粘合剂后,滤材抗张力强度明显增大,滤材孔径减小。随油雾加载率增大,滤芯过滤层液体运移通道数增加,通道压降升高。初始压降随表观过滤速度增加而升高。粘合剂主要凝固在渗透性低的区域,压降变化较小。表观过滤速度增加抑制了二次夹带,折叠滤芯过滤效率升高,而由于粘合剂脱落,涂覆粘合剂的滤芯过滤效率下降。表观过滤速度为0.10 m/s时,随油雾加载率增大,聚结在滤材表面的粘合剂抑制夹带,滤芯过滤效率升高。 相似文献
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Seok-Jun Yoa Yong-Soo Cho Yong-Seok Choi Jong-Hun Baek 《Korean Journal of Chemical Engineering》2001,18(4):539-546
The main purpose of this study was to investigate experimentally the characteristics of an electrostatic cyclone/bag filter
with inlet types (upper and bottom inlet) in order to overcome the low collection efficiency for submicron particles and high
pressure drop, which were the main problems of general fabric bag filters. The experiment was performed to analyze the collection
efficiency and pressure drop of the electrostatic cyclone/bag filter compared with that of conventional fabric bag filters
with various experimental parameters such as the inlet type (upper and bottom), inlet velocity (filtration velocity) and applied
voltages. From the results, the upper inlet type showed a slightly higher pressure drop reduction ratio as 40–90% than that
of bottom inlet. In addition, the electrostatic cyclone/bag filter represented an increment of over 5% for the collection
efficiency of submicron particles (around 1 Μm) in comparison with the general fabric filter.
Presented at the Int’/Sym. on Chem. Eng. (Cheju, Feb. 8–10, 2001), dedicated to Prof. H. S. Chun on the occasion of his retirement
from Korea University. 相似文献
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通过冷模实验,改变移动床表观气速、颗粒循环速率、入口气体含尘浓度等操作参数,研究了轴向移动床过滤器的压降特性和合适的操作条件,结合移动床内气固两相运动特点,修正了Ergun公式,在加尘条件下分析了床内滤饼对压降稳定性的影响。结果表明,在无尘负荷条件下(“纯”移动床操作),颗粒的循环速率由0增至2.26 kg/(m2?s)时,设备的压降减小0.03 kPa。表观气速为0.126 m/s、入口气体含尘浓度为89.10 g/m3时,移动床内滤饼形成和破损呈动态平衡,过滤500 s后,压降可稳定在0.88 kPa,此时设备具有较高的除尘性能,粉尘捕集效率可达96%以上。 相似文献
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In order to observe the effect of particle shape of poly-dispersed dusts on filter performance, the pressure drop across the
dust cakes of fly ashes from a conventional power plant (PC), fluidized bed combustion (FBC), and paint incinerator (FI) was
measured over a metal filter element in the accurate conditions. A fluidized bed column was used to prepare the dust feed
stream of uniform particle distribution. The fine particles of FI ash have a tendency to be agglomerated at low transport
velocity. The aggregates were broken at high velocity of more than 21 cm/sec. FBC ash composed of jagged type particles and
containing high concentration of unburned-carbon showed higher pressure drop than that of PC ash composed mostly of spherical
particles. FI ash composed of aggregates of very fine carbon particles presented the highest pressure drop among the fly ashes
tested. The shape factors of PC, FBC, and FI ash were estimated as 0.91, 0.76, and 0.65, respectively, by the Ergun equation.
The results implied that the irregular particle tends to form a higher pressure drop and to be more compressible than spherical
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This paper is dedicated to Professor Wha Young Lee on the occasion of his retirement from Seoul National University. 相似文献
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Deqiang Jiang Weidong Zhang Junteng Liu Wang Geng Zhongqi Ren 《Korean Journal of Chemical Engineering》2008,25(4):744-753
With micron talcum particles and nano-CaCO3 powder as test dust, a series of experiments have been carried out to systematically study the gas filtration and regeneration
behavior of polytetrafluoroethylene membrane, and some comparisons were made with common filter media. The experimental results
showed that the PTFE membrane had a filtration efficiency of above 99.99% for micron particles, and excellent regeneration
behavior was obtained, though a much higher initial pressure drop existed. Based on the results, it was concluded that the
PTFE membrane is an excellent surface-filtration media for micron particles. Effects of operation parameters, including airflow
velocity, particle concentration and particle characteristics were also investigated. To better understand the evolution of
pressure drop during the filtration process, a mathematical model with operation parameters and characteristics of particles
was derived from the gas-solid two-phase flow theories. A novel method on the determination of regeneration period of the
filter media was put forward based on the analysis of the pressure drop according to this model. 相似文献
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This paper reviews the concept of filter quality (qF) for dust filtration media composed of different structures: metal fiber beds (MFB), fabric filters (BF), and fly ash filters (FAF). Filter quality is a useful index of the filtration performance, which incorporates both pressure drop and filtration efficiency. Major parameters affecting the filter quality are filtration velocity in the range of 0.06-0.19 m/s, dust loading, porosity of the medium in the range of 75-93%, and internal structure of the medium. The experimental observation showed that filter quality decreased with increasing filtration velocity or dust concentration. A unique increase in filter quality during the initial stage of filtration appeared with the FAF as a result of the predominately surface filtration with less pore clogging. Nevertheless, the filter quality cannot be taken as an absolute indicator of filter performance, but rather it should be used just as a reference parameter depending on operating conditions. The results of this work show that fly ash filters are capable of providing more stable performance, particularly during the initial stage of filtration, and thereafter of a certain time filter quality initiates to decline as other filters. 相似文献
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An experimental study was conducted to assess the possibility of determining particle holdup by measuring the pressure drop of a conventional cyclone used in a circulating fluidized bed (CFB) boiler. It was found that within a wide range of inlet solid concentrations, i.e., 0.54–4.42 kg/kg‐gas, the cyclone pressure drop increased linearly with inlet solid concentration at a given gas velocity, while the pressure drop between the dust exit and the vortex finder of the cyclone remained almost constant. Since particle holdup increases virtually linearly with solid flow rate, the particle holdup in the cyclone can be derived from the cyclone pressure drop, and therefore, an equation set was proposed to calculate the particle holdup from the cyclone pressure drop. 相似文献
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A centrifugal separator was constructed to examine the effect of flue gas humidity on the adhesional force between fabric
and collected dust. A lab-scale fabric filter sampling system (FFSS) was also manufactured by using a piece of flat fabric
as a sample of bag material. In addition, an automatic control system for gas humidity was devised and installed in the FFSS,
and, then, the following effects were studied: (i) the influence of gas humidity on the adhesional force between fabric and
dust particles; (ii) the influence of gas humidity on the performance of fabric filter in terms of pressure drop, ΔP, dust
removal efficiency, η, and specific cake resistance, K′2; (iii) the variations in the composite-performance indices with gas humidity; and (iv) the influence of gas humidity on cleaning
of dust-cake in terms of effective residual pressure drop. The main objectives were to determine the minimum and maximum values
for the gas humidity range and to find the appropriate conditions for dust cleaning in terms of the critical value of effective
residual pressure drop. 相似文献
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除油旋流器入口流量与基本性能的关系研究 总被引:1,自引:0,他引:1
对除油旋流器边壁的油滴粒径变化、旋流器的分离效率以及压力降与入口流量之间的关系进行了研究。结果表明 ,当入口流量达到一定程度时 ,旋流器边壁的平均粒径随入口流量的增加而降低 ,分离效率随入口流量的增加而增加。整个旋流器以及旋流器各段的压力降均与入口流量成指数关系 ,都随入口流量的增加而增加。在旋流器的压力损失中 ,进口、旋流腔及大锥段所占比例最大 ,且基本不随入口流量的变化而变化 ;小锥段次之 ,并随入口流量的增大而增大 ;直管段的压力损失所占的比例最小 ,它随入口流量的增大而不断降低。 相似文献