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褐煤的热处理改质研究 总被引:11,自引:1,他引:10
对水含量较高的Banko褐煤进行了蒸发干燥处理和煤油成浆覆盖沥青干燥处理,并用热重和热台红外等对所得煤样的组成,结构和反应行为进行了考察。结果表明,煤油成浆热处理并覆盖沥青既能达到较好的脱水效果,还能适当增加煤的氧化反应活化能,从而降低煤的低温氧化反应性,达到抑制干燥煤自燃的目的。不过,为明显降低煤的低温氧化反应性,还需改变实验条件进行进一步研究。 相似文献
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介绍了热水干燥褐煤的方法及机理,在高压釜内加热干燥褐煤,可永久改变低阶煤的物理和化学性质,褐煤的最高内在水分显著下降,发热量提高,表面疏水性增强;利用干燥后的褐煤制备水煤浆,具有良好的成浆特性、流变特性及稳定性。 相似文献
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针对褐煤易风化变质,化学反应性强,热稳定性差,富有自燃倾向,不适宜长距离运输等特点,对国内外褐煤干燥技术进行了研究,归纳总结了各干燥技术的工作流程、优缺点及应用情况。介绍了褐煤干燥成型技术的工作原理,并对其可行性进行了应用试验研究,结果表明:干燥成型的褐煤中,Mt都低于0.10%,Mad低于0.01%,Qnet,ar可达到25.03 kJ/g,与原煤相比提高了46.12%。褐煤干燥成型技术可有效提高褐煤煤质,降低系统复杂性,干燥成型后褐煤的化学稳定性明显提高,褐煤干燥成型在技术上是可行的。 相似文献
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褐煤干燥成型工艺技术综述 总被引:5,自引:2,他引:3
褐煤干燥成型技术是将成本低廉的富含水分的褐煤在一定温度下经脱水后转化成为具有类似烟煤性质的提质煤。提质后的褐煤更有利于综合利用、运输和贮存,且具有可观的经济价值。介绍了国外7种褐煤干燥工艺技术和褐煤热压成型技术;着重论述了管式间接干燥工艺和高压热压成型工艺的干燥过程、成型过程、工艺特点及优缺点;通过工艺设计数据、物料衡算基准和关键设备配置,例举了褐煤干燥成型工艺设计应用实例;分析和论证了褐煤成型过程的性能保证和安全性保障。对褐煤干燥成型生产装置进行了技术经济评价,结果表明:建设1套百万吨级的褐煤干燥成型工厂,其建设投资约为3.8亿元,型煤加工成本约为60元/t。 相似文献
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Yunlong Yang Xiaoxia Jing Zhiqiang Li Xiao Liu Yulong Zhang 《Drying Technology》2013,31(12):1430-1437
In order to improve the drying efficiency of lignite and restrain the moisture re-adsorption of dewatered coal, the drying characteristics of typical Chinese lignite, the re-adsorption performances of dewatered samples and the change in pore structure throughout the entire processes were investigated in this study. Lignite samples with four different particle size fractions were dried in a fixed-bed reactor in the temperature range 60–160°C. The re-adsorbing moisture behaviors of dewatered coal samples containing different water contents were investigated at temperatures of 20–40°C and humidities of 55–95%. The changes in the pore structure of raw coal and different dried samples were measured by mercury intrusion porosimetry (MIP) and the relations between their re-adsorption performance and change in pore structure were explored. The moisture removal yields of lignite increased with an increase in drying time and temperature and was close to 100% above 120°C and over 100% after holding 40 and 15 min at temperatures of 140 and 160°C due to the release of CO2 from the decomposing carboxyl group in the coal matrix. The re-adsorbed moisture content in dewatered coal was influenced by drying temperature and coal particle size through varying pore structure. The temperature and relative humidity in the re-adsorbing process were the main factors that influenced the moisture re-adsorption capacity of dewatered lignite, in which the re-adsorbing temperature mainly operated by varying the bonding ability of water on the surface of dewatered coal, and the relative humidity was connected with the pore structure as well. The mesopore was the main factor that influenced the re-adsorption of dewatered coal and the re-adsorption of moisture in dewatered coal at 100°C was highest due to the narrow range of the pore radius and because the relative volume ratio of 5 to 50 nm mesopore (above 91%) was high. The water loss yield of lignite with smaller particle size was higher due to its larger pore volume and surface area, but its re-adsorption capacity was lower because of lower volume ratio of 5 to 50 nm mesopore volume in dewatered coal obtained from the smaller size lignite. 相似文献
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褐煤干燥提质技术浅谈 总被引:2,自引:0,他引:2
介绍褐煤的基本性质和几种褐煤的干燥提质技术,如管式干燥技术、蒸汽流化床干燥技术(DWT法)、热脱水工艺和LFC褐煤干燥等,简单分析各工艺,展望褐煤干燥提质的前景. 相似文献
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褐煤是煤化程度最低的煤种,为泥炭在适度压力下转变而成,煤化程度低,用作气化原料存在许多缺陷,如高水分、高灰分、熔点变化大、机械强度低、热稳定性差、煤气粉尘含量大、料层透气性差等。但将褐煤提质后制备高浓度水煤浆,再通过水煤浆气化加以利用是褐煤利用的一个新途径。本文通过对褐煤原煤和提质型煤成浆特性的研究,通过级配试验、添加剂试验、成浆浓度试验等,得出褐煤经提质后成浆性可以得到很大的提高,为褐煤应用拓宽了应用领域。 相似文献
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改性粉煤灰处理含磷废水的研究 总被引:5,自引:0,他引:5
采用浓硫酸固相反应法对粉煤灰进行改性用于含磷废水的净化,考察了pH值,吸附剂用量,磷初始浓度,反应时间对净化过程的影响。通过实验发现溶液pH值在4-10范围内对磷的吸附过程影响不显著,改性粉煤灰可以在较宽的pH值范围内进行脱磷处理;随着粉煤灰加入量的增加和初始溶液中磷酸根浓度的降低,磷的净化率逐渐增加。对于含磷50 mg/L的溶液,当粉煤灰的投加量为1.5%时,磷的吸附效率可达99.66%,净化后水中含磷量为0.17 mg/L。改性粉煤灰对水中磷的净化过程速度较快,5 min可达到最大净化率。改性粉煤灰对磷的吸附等温线符合Freudlich方程。 相似文献
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茭白片热风对流干燥模型与传质性能 总被引:3,自引:0,他引:3
诸爱士 《高校化学工程学报》2012,26(3):541-546
为了探讨茭白干燥的传递特性,在对流热风干燥实验装置中进行了茭白片薄层干燥实验,研究了干燥温度、片的厚度对干燥过程的影响,将试验的水分比与数学模型进行了拟合,计算了不同温度下的水分扩散系数,并关联了其与干燥温度的关系.结果表明:干燥温度对干燥过程影响显著,薄片有利于水分扩散:用Page模型来描述茭白片热风干燥动力学令人满意;茭白片厚度为0.003m时,随风温升高,水分扩散系数从3.440×10-9 m2·s-1增大到6.357×10-9m2·s-1,并符合阿累尼乌斯方程,活化能为27.86 kj·mol-1.相同温度下,物料中水分的扩散系数基本不受厚度影响. 相似文献