共查询到19条相似文献,搜索用时 78 毫秒
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《煤炭加工与综合利用》2017,(6)
对以低温干馏为基础的低阶煤分质利用技术进行了分析,提出了煤低温干馏分质综合利用技术的发展方向;重点结合竖炉内热式低温干馏工艺存在的问题,提出了解决方案,并介绍了富氧干馏、新型干熄焦、废水消纳、碎煤分级入炉、微波干馏等技术开发状况,对相关技术产业化应用前景进行了展望。 相似文献
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结合神府低变质煤的特点,采用低温干馏工艺实现煤的清洁高效利用;运行结果表明:炭化炉稳定运行后,火道正常温度为86.5℃,中部温度为628℃,中上部温度可根据市场需求进行调整;燃气比控制在2.0,可以实现炉体干馏区域的最大化,增加回炉煤气流量,可以提高中上部温度,提高各粒径兰炭的固定碳含量。 相似文献
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在内热式低温煤干馏中,引入富氧燃烧,同时提高煤气当量比,是在维持炉内温度分布基本不变的前提下提高煤气质量的有效途径。通过不同富氧比及不同尺寸烧嘴下的大当量比煤气/富氧燃烧实验结合数值模拟分析,探究了富氧低温干馏中的内热火焰温度分布特性及其受工艺条件和烧嘴尺寸的影响。结果表明:增大富氧比的同时增大燃料当量比可以维持平均火焰温度与空气助燃工况基本一致,但火焰锋面温度受局部当量比及流动条件影响;减小燃料及氧化剂射流的初始速度差,可以减缓组分混合、延长火焰并降低火焰锋面温度;煤气中三种气体按参与反应的速率快慢排序依次为氢气、一氧化碳、甲烷,随着燃烧反应进入湍流混合速率控制模式,组分间的选择性燃烧特征相对减弱。 相似文献
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《中国石油和化工标准与质量》2013,(22)
所谓低温干馏技术是指使用较低加热终温,约为500600℃,以使得煤始终处于隔绝空气条件下,逐渐受热而分解成为煤气、半焦以及低温煤焦油等物质的过程。本文以低温干馏技术为基础,对粉煤干馏工艺进行研究与探索。 相似文献
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《煤炭加工与综合利用》2016,(2)
选用有机粘结剂,将低变质粉煤冷压成型煤,经中温干馏制备兰炭,研究了不同粘结剂对型煤、兰炭的落下强度和抗碎强度的影响;单一聚酰胺树脂、两种以及三种粘结剂复配的用量分别为14%、13%、12%时,兰炭的两种强度接近,粘结剂用量均为12%时,三种粘结剂复配的兰炭落下强度为94.6%、抗碎强度为54.2%,优于单一和两种粘结剂复配的强度;不同粘结剂对型煤的落下强度、抗碎强度影响较小,随着粘结剂用量的增加,型煤的两种强度均在增大,当粘结剂用量超过12%后,两种强度的增幅不明显。 相似文献
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随着我国对大气污染物排放监管力度的日益严格,NOx控制技术已广泛应用于工业生产的各个领域。作为一种直接、简便的NOx排放控制技术,富氧空气燃烧技术已经出现在燃气锅炉和内燃发动机等行业,然而在燃煤锅炉行业中却鲜有应用。为了验证富氧空气燃烧技术在煤粉工业锅炉中的NOx减排效果,笔者以神府烟煤作为燃料,利用两段式滴管炉试验系统模拟煤粉在锅炉内燃烧的实际情况,采用热态试验方法,研究了烟煤富氧空气分级燃烧的NOx排放特性,并与单级供风、空气分级燃烧2种燃烧方式下的NOx排放情况进行对比。考察了主燃区温度、二次风配比(以主燃区过量氧气系数表示)、二次风氧浓度等关键因素对NOx排放的影响。结果表明:富氧空气分级燃烧的NOx排放显著低于单级供风燃烧,同时也低于空气分级燃烧的NOx排放。主燃区温度为1 300~1 500℃时,富氧空气分级燃烧的NOx排放减少比例比分级配风燃烧提高了6~12个百分点;富氧空气分级燃烧条件下,随主燃区温度升高,煤粉燃烧更加充分,燃料中N元素分解成NHi、HCN等大量中间产物,使主燃区气氛的还原性增强,被还原的NOx比例增加。因此,NOx排放降低且NOx排放减少比例呈现上升趋势;富氧空气分级燃烧的二次风配比对NOx排放具有显著影响,随着主燃区过量氧气系数的升高,NOx排放均呈现先降低后升高的趋势。因此存在最佳二次风配比,使NOx排放浓度最低。主燃区温度为1 300℃时,最佳主燃区过量氧气系数约为0.58;主燃区温度为1 500℃时,最佳主燃区过量氧气系数约为0.55;在主燃区过量空气系数给定的条件下,提高二次风氧浓度可以延长煤粉颗粒在主燃区的停留时间,并在煤粉颗粒表面形成局部富氧环境,促进煤粉充分燃烧,从而增强主燃区气氛的还原性,降低NOx的生成。因此,当二次风氧浓度为21%~31%时,NOx排放随二次风氧含量的升高而降低。随着二次风氧浓度的逐渐升高,NOx排放的降低趋势逐渐放缓。 相似文献
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High temperature air combustion experiments for pulverized coal in a large-scale furnace have been done before and shown that the NO emission in the high temperature air combustion is significantly lower than that in the normal temperature air combustion. This paper numerically studies the NO evolution in the large-scale experiments with a simplified chemical reaction model. Through an analysis of numerical results a low NO emission mechanism in the high temperature air combustion has been presented. If the HCN concentration is high, the NO generation is fast. But, the high HCN and NO concentrations together will make NO destruction fast. It is found that, by properly arranging flow patterns, the high HCN and NO concentrations can be obtained in the vicinity of primary air nozzle. Thus, the generation and destruction of NO can reach an equilibrium point so that the net NO emission rate is low. 相似文献
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Dae Hun Chung Jae Bok Yang Dong Sun Noh Won Bae Kim 《Korean Journal of Chemical Engineering》1999,16(4):489-493
High temperature preheated and diluted air combustion has been confirmed as the technology, mainly applied to industrial furnaces and kilns, for realizing higher thermal efficiency and lower emissions. The purpose of this study was to investigate fundamental aspects of the above-mentioned combustion experimentally and to compare with those in ordinary hydrocarbon combustion with room temperature air. The test items were exhaust gas components of CO, NOx, flame shape and radical components of CH, OH and C2, which we measured with gas analyser, camera and ICCD (Intensified Charged-Coupled Device) camera. Many phenomena, as a result, which appeared in the combustion with the oxidizer, low oxygen concentration and extremely high temperature air, such as expansion of the flammable limits, increased flame propagation speed, looked very strange in comparison with those in existing combustion technology. We confirmed that such extraordinary phenomena were believable through a hot-test experiment. 相似文献
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《Fuel》2002,81(11-12):1477-1484
Several coals were pre-oxidized by air at 250, 270 and 300 °C to different levels, then the carbonization behaviors of the pre-oxidized coals were systematically examined. The gas formation rates and weight change during the carbonization were measured continuously using a mass spectrometer and a thermogravimetric analyzer, respectively. The changes in the functional groups during the carbonization were measured by an in situ FTIR technique. The micropore distributions of the pre-oxidized coals were measured before and after the carbonization. From these measurements the effect of pre-oxidation on the carbonization of coal was examined in detail. 相似文献
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陕北煤低温干馏生产工艺及改进建议 总被引:1,自引:0,他引:1
结合陕北地区煤低温干馏生产工艺现状,提出了煤低温热解工艺的改进方案。对国内外几种典型的固体热载体煤干馏工艺进行了比较和评述,针对目前陕北地区煤炭资源综合利用和环境保护的需要,认为循环流化床燃烧和煤炭低温热解的集成工艺具有良好的发展前景。 相似文献
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Wei Xie Haifeng ChengZengyong Chu Zhaohui ChenChunguang Long 《Ceramics International》2011,37(6):1947-1951
A series of polyacrylonitrile-based hollow carbon fibres (PAN-HCFs) were prepared by carbonizing polyacrylonitrile (PAN) hollow cured fibres at temperature ranging from 550 to 950 °C for 1 h in nitrogen. The effects of carbonization temperature on the structure, elemental compositions, surface electrical conductivity, electromagnetic parameters and reflectivity of PAN-HCFs were investigated. Results indicate that the obtained PAN-HCFs have not been graphitized and the C content and surface electrical conductivity increases as the carbonization temperature increases. The reflectivity of composites of PAN-HCFs and resin is −7.50 dB at 6.06 GHz and the band of the reflectivity under −5 dB is 6 GHz when the carbonization temperature is 750 °C. 相似文献