共查询到20条相似文献,搜索用时 46 毫秒
1.
采用氢化物发生器和原子荧光光谱法联用(HG-AFS)和电感耦合等离子发射光谱法(ICP-AES),测定了常压流化床煤气化产物中As、Cd、Co、Cr、Cu、Mn、Mg、Ni、Hg、Pb、V、Se、Sr、Zn 14种痕量元素含量,分析了空煤比对痕量元素在气化产物中迁移规律的影响。结果表明:在旋风高温焦中,CA、Ni富集,As、Co、Cu、V、Se、Hg耗散;空煤比对Mn、Sr、Hg、Se、As影响不大;随着空煤比增加,Pb、Zn、Cu、Co、Ni的相时富集系数(REs)略微增加,Cd、Mg的REs减少;V、Cr在低空煤比条件下有较高的REs。在布袋低温焦中,Cd、As、Cu、Cr、Ni、Pb、Zn富集,Co、V、Se、Hg耗散;随着空煤比增加,Pb、Cu、Ni的REs增加;Cd、As、Cr、Se的REs减少。底渣中的Mn和Sr相对于高、低温焦而言有轻微的富集。随着空煤比增加,Cu、Zn在煤气中含量增加,Cr、Co、As、Hg在煤气中含量减小。 相似文献
2.
采用Z-8200型原子吸收分光光度计和VF-320型X射线荧光光谱仪,定量测定了1台220t/h煤粉炉中原煤、底渣、飞灰中8种痕量元素的含量。基于改进的Meij相对富集系数,从底渣和飞灰两个方面,系统分析了温度、含氧量、飞灰粒径、痕量元素自身性质以及煤种特性迁移规律的影响。研究结果表明:炉膛温度升高能加快部分痕量元素的挥发;Cr和Mn在飞灰、废渣中含量相当,但两者相对富集系数明显不同;含氧量低并非促进所有痕量元素挥发;Pb、Cd、Zn、Cr在底渣和飞灰中含量并不一定都与各自的沸点成单一的关系;飞灰粒径越小,痕量元素富集系数越大,各痕量元素随飞灰粒径减小的变化趋势并不相同等。 相似文献
3.
采用氢化物发生器和原子荧光光谱法联用 (HG -AFS)和电感耦合等离子发射光谱法 (ICP -AES) ,测定了常压流化床煤气化产物中As、Cd、Co、Cr、Cu、Mn、Mg、Ni、Hg、Pb、V、Se、Sr、Zn 1 4种微量元素含量 ,分析了汽煤比对微量元素在气化产物中迁移规律的影响。结果表明 :随着汽煤比增加 ,在旋风高温焦中Co、Cu的相对富集系数 (REs)先减小再增加 ;Cd、Ni的REs先增加再减小 ;Pb、Zn的REs减小 ;Cr、Mn、Mg、V和Sr的REs受汽煤比的影响很小 ;易挥发性元素As、Hg、Se的REs在高汽煤比条件下略微有上扬的趋势。随着汽煤比增加 ,在布袋低温焦中Cd、Co、Cu、Ni的REs先增加后减小 ;As、Hg、Pb、Se、Zn的REs减小。底渣中易挥发性元素As、Hg、Se的REs受汽煤比的影响不及部分挥发性元素Cd、Cr、Cu、Ni、Pb、Zn那么明显。随着汽煤比增加 ,在煤气中As、Cr、Zn的含量减小 ,Co、Cu的含量先增加后减小。 相似文献
4.
5.
循环流化床煤燃烧产物中微量元素分布特征 总被引:3,自引:0,他引:3
利用清华大学小型循环流化床对黔西南坑硫煤进行燃烧实验,研究循环流化床燃烧过程中煤中微量元素在燃烧产物中的重新配置和对环境的影响,以及固硫添加剂对煤中部分有害微量元素排放的控制作用,结果表明,循环流化床灰中,As、Sb、Pb、Cu、Be与Zn等在细粒灰中富集,Pb、As、Sb、Se、Th、Ni与Cr等在磁性灰中富集。除尘器后烟道灰中富集Zn、As、P、Ni、Cr、Mo、Be、Pb、Th、Hg与F等,而Nb、Rb与Zr等明显亏损。在煤中加入固硫添加剂燃烧后比较发现,As、Se、Sg与Zn等在细粒流化床灰中富集能力降低,As、Se、Li、Be、Mo、Cr、Co与Ni等在除尘器后烟道灰中含量降低,烟道喷淋水中Cu、Zn、Cr、Pb、Co、Ni、F与Se等的含量降低。循环流化床燃烧过程中,固硫添加剂不仅降低SO2的排放,而且对部分有害微量元素(As、Se、Be、Cr、Co、Ni、Pb、Zn与F等)的排放有一定的控制作用。 相似文献
6.
7.
高炉氧煤燃烧器中煤粉燃烧过程的数值模拟 总被引:2,自引:0,他引:2
本文采用颗粒相连续介质-轨道模型对同轴射流渐扩式高炉氧煤燃烧器内煤粉燃烧过程进行了数值模拟。数值模拟结果表明,同轴射流渐扩式氧煤燃烧器在适当的射流速度比条件下,可在氧煤枪出口后方诱导出回流区及低速区,有利于延长煤粉在直吹管内的停留时间,改善煤粉在热风管中加热、挥发和挥发份的着火条件,改善氧气和煤粉的混合,提高煤粉燃烧区的氧气浓度。 相似文献
8.
优化配煤应用于燃煤电厂的燃烧试验研究 总被引:1,自引:0,他引:1
浙江省某电厂2台125MW机组,配2台410t/h四角切圆燃烧煤粉炉,由于其设计煤种实际上无法采购,因而长期烧的煤种较杂,很大程度上取决于煤炭的市场供应情况及运输途径。过去多烧两淮煤为主,近年也经常试烧北方煤。由于炉子较老旧,最大的问题主要是易导致4号炉结焦结渣、飞灰含碳量有时偏大等。针对这种情况,对该电厂配送了在杭州煤场配制的优化配煤,并进行了燃烧调试及热工环保测试,取得可喜的效果。图1表3参11 相似文献
9.
10.
11.
A preliminary method for determining acceptable trace element levels in coal was established. In addition to the conventional coal quality parameters ash and sulfur, potentially hazardous trace elements As, Be, Cd, Cl, Cr, F, Hg, Mn, Ni, Pb and Se were selected for the evaluation, and their environmentally acceptable concentrations in coal were quantified at 5 and 0.5 weight %, and 6.5, 1, 0.8, 400, 15, 120, 0.15, 80, 30, 15 and 2.5 mg/kg, respectively. A pollution index (I) is proposed, by which coal is ranked into four classes: acceptable (I ≤ 0.252), marginal (0.252 < I ≤ 0.514), unacceptable (0.514 < I ≤ 0.751), and ultra-unacceptable coal (I > 0.751). 36 coal samples collected from the north of Ordos basin and Shanxi Province, China were classified with the method. Most of the cleaned coals were rated as acceptable or marginal, while the run-in-mine coals, feed coals, middlings and coal slimes were generally ranked as unacceptable or ultra-unacceptable coal. The evaluation results reflect the degree of cleanliness of these coal samples. 相似文献
12.
Zhang Junying Zhao Yongchun Ding Feng Zeng Hancai Zheng Chuguang 《Frontiers of Energy and Power Engineering in China》2007,1(3):273-279
Hazardous trace element emissions have caused serious harm to human health in China. Several typical high-toxic trace element
coals were collected from different districts and were used to investigate the emission characteristics of toxic trace elements
(As, Se, Cr, Hg) and to explore preliminary control methods. Coal combustion tests were conducted in several bench-scale furnaces
including drop tube furnace (DTF), circulating fluidized bed (CFB) combustion furnace, and fixed-bed combustion furnace. Calcium
oxide was used to control the emission of arsenic and selenium. The granular activated carbons (AC) and activated-carbon fibers
(ACF) were used to remove mercury in the flue gas from coal combustion. The chemical composition and trace element contents
of ash and particulate matter (PM) were determined by X-ray fluorescence (XRF) spectrometry and inductively coupled plasma-atomic
emission spectrometry (ICP-AES), respectively. The speciation and concentration of mercury were investigated using the Ontario-Hydro
method. X-ray diffraction spectrometry (XRD) was used to determine the mineral composition of production during combustion
experiments. With the addition of a calcium-based sorbent, arsenic concentration in PM1 sharply decreased from 0.25–0.11 mg/m3. In fixed-bed combustion of coal, the retention rates of selenium volatiles were between 11.6% and 50.7% using lime. In the
circulating fluidized-bed combustion of coal, the content of selenium in ash from the chimney was reduced to one-fourth of
its original value and that in leaching water from the chimney decreased by two orders of magnitude using lime. Calcium-based
sorbent is an effective additive to control the emission of As and Se during coal combustion. The emission of chromium is
influenced by the occurrence mode of Cr in coal. Chromium emission in PM2.5 during coal combustion is 55.5 and 34.7 μg/m3 for Shenbei coal and mixed Pingdingshan coal, respectively. The adsorptive capacity of granular activated carbon for Hg0 is significantly enhanced through ZnCl2-impregnation. The activated carbon fibers showed decent efficiency in mercury adsorption, on which surface oxygen complex
showed positive effects on mercury adsorption. 相似文献
13.
《Energy Conversion and Management》2005,46(13-14):2001-2009
The mineral and chemical compositions and some trace element contents (As, Ba, Cr, Mn, Mo, Sb, Th, U and V) in coal and coal ash samples from the Huaibei coal field in China were studied. This high volatility bituminous coal has low moisture and S contents, moderate ash yield and high calorific value. The coal ash is abundant in aluminosilicates as the contents of the Fe oxides are relatively similar to the sum of the alkaline earth oxides. The minerals identified in the coal are mainly quartz, kaolinite, pyrite and calcite and, to lesser extents, dolomite, ankerite, illite, chlorite, opal, feldspars, marcasite, gypsum, melanterite and hematite. Common minerals in the high temperature ash (815 °C) are original quartz and newly formed anhydrite, lime, hematite and Ca–Mg silicates. Some trace elements such as Cr > Th > V > Mo in the coal (in particular Cr and Th) and Cr > Th > V in the coal ash (in particular Cr) are enriched in comparison with the Clarke concentrations. 相似文献
14.
15.
《International Journal of Hydrogen Energy》2021,46(70):34652-34662
The release behavior of biomass and coal in the co-pyrolysis process was investigated. The release characteristics of the small molecules from 100 to 1000 °C were researched by TG-MS at the heating rate of 30 °C/min. The pyrolysis products during the co-pyrolysis process were compared with that in the separate pyrolysis process. It is found that the changes of pyrolysis products in the co-pyrolysis process are similar to that in the separate pyrolysis process. The main pyrolysis products of the biomass are released at the temperature lower than 500 °C. Some of the small molecules of Shenfu coal release at the temperature higher than 900 °C. The yields of aromatic compounds in biomasses are lower than that in Shenfu coal. In addition, most of the raw materials are pyrolyzed independently during the co-pyrolysis process. The differences between the experimental values and calculated values are slightly. With the addition of biomass, the content variations of aromatic compounds are not significant. 相似文献
16.
17.
Yuanpeng Fu Weining Xie Jie Wang Xuejie Bai Jinlong Li 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2019,41(14):1663-1673
The strong hydrophilic properties of both sub-bituminous coal and kaolinite make it difficult to separate by direct flotation. In this paper, the removal of kaolinite from fine sub-bituminous coal was investigated by reverse flotation tests using N, N-dimethyl dodecyl amine (DRN12) as a kaolinite collector. In addition, the adsorption behavior of DRN12 on coal and kaolinite surfaces was also studied to explore its interaction mechanism The experimental results showed that the beneficiation of kaolinite from the raw coal was effective only in the acid pulp with DRN12 less than 1.5kg/t. Moreover, in acid solutions, DRN12 preferentially adsorbs on kaolinite surface by electrostatic force, and the adsorption capacity of DRN12 on kaolinite surface was much higher than on coal, which caused an increase of kaolinite hydrophobicity and floatability. 相似文献
18.
The U.S. Department of Energy is currently working on coupling coal gasification and high temperature fuel cell to produce electrical power in a highly efficient manner while being emissions free. Many investigations have already investigated the effects of major coal syngas species such as CO and H2S. However coal contains many trace species and the effect of these species on solid oxide fuel cell anode is not presently known. Warm gas cleanup systems are planned to be used with these advanced power generation systems for the removal of major constituents such as H2S and HCl but the operational parameters of such systems is not well defined at this point in time. This paper focuses on the effect of anticipated warm gas cleanup conditions has on trace specie partitioning between the vapor and condensed phase and the effects the trace vapor species have on the SOFC anode. Results show that Be, Cr, K, Na, V, and Z trace species will form condensed phases and should not effect SOFC anode performance since it is anticipated that the warm gas cleanup systems will have a high removal efficiency of particulate matter. Also the results show that Sb, As, Cd, Hg, Pb, P, and Se trace species form vapor phases and the Sb, As, and P vapor phase species show the ability to form secondary Ni phases in the SOFC anode. 相似文献
19.