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干煤粉气化炉下渣口结构的设计及应用对比分析
对干煤粉气化技术发展方向进行了综述，并重点研究了气化炉下渣口结构。通过对比不同下渣口结构的制造、安装、运行、检修的难易程度，以及对不同下渣口结构在运行中可能出现的风险进行识别(水冷壁的磨损、下降管的烧损等)，具体对比了两种已应用的气化炉渣口水冷壁与下降管组合结构的优缺点，并给出推荐理由。...
2020-07-12 21:36:56浏览：74
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煤气化装置中蒸汽管道的设计要点分析
蒸汽作为煤气化装置中重要的工艺及公用工程物料，对煤气化装置生产运行至关重要，本文结合煤气化装置的布置特点，对煤气化装置中不同用途的蒸汽管道的布置特点进行分析与研究，提出了煤气化装置蒸汽管道的布置要点及建议。...
2020-07-12 21:36:56浏览：61
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宁夏石沟驿煤气化残炭燃烧特性研究
利用TG/DTA 6300型热分析仪研究了宁夏石沟驿煤的气化残炭的燃烧特性,从着火特性、燃尽特性和稳燃特性三个方面分析了升温速率、粒径和氧气浓度对气化残炭燃烧特性的影响,并采用正交实验分析了升温速率、粒径和氧气浓度三个因素对气化残炭燃烧特性影响的耦合作用.实验结果表明,提高升温速率可以改善气化残炭的燃尽特性；粒径的减小有助于气化残炭的着火；氧气浓度的增加对改善气化残炭燃烧特性有明显的作用,但这种改善效果随氧气浓度的增加而减弱；升温速率对气化残炭的着火特性影响最大,而氧气浓度对气化残炭的燃尽特性和稳燃特性影响最大....
2020-07-12 21:36:56浏览：73
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鼓泡流化床内粉煤气化的数值模拟
将应用欧拉双流体模型对鼓泡气化炉内的气化过程进行研究.摒弃传统颗粒动理学理论中颗粒光滑无旋转的假设,引入颗粒的旋转运动,构建粗糙颗粒动理学理论来封闭双流体模型.基于燃烧理论建立粉煤热解、气化模型以及鼓泡床内气固之间以及气体和气体之间的传热、传质模型.采用该模型进行数值模拟计算,分析床内的气固反应过程,对比实验结果表明粗糙颗粒动理学理论适用于模拟鼓泡床气化炉内的反应....
2020-07-12 21:36:56浏览：42
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壳牌煤气化技术在国内的应用与技术创新
壳牌煤气化技术进入中国已近10年,随着其工艺技术的完善、运转经验的积累和操作水平的提高,目前大多数装置已能实现长周期稳定运行。简述了国内壳牌煤气化装置的建设概况及总体使用情况;分析了装置运行中普遍存在的问题及其原因;总结了控制气化炉炉温、测量粉煤输送速度等操作经验;介绍了合成气冷却器积灰结垢等故障处理办法;概述了壳牌煤气化装置的技术创新及进展。...
2020-07-12 21:36:56浏览：70
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Shell粉煤气化工艺控制优化与改进
针对Shell粉煤气化工艺技术特点，对在调试、投料期问常出现影响装置连续操作的主要问题进行了研究，结合装置实际情况，提出了解决此类问题的工艺控制优化与改进方案，并对此进行了合理性分析。经过实际应用和检验，优化和改进方案对工艺运行顺畅、保护设备起到了良好的作用，也为气化炉的长周期运行提供了技术保障。...
2020-07-10 14:39:05浏览：34
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基于Aspen Plus的煤气化副产物粗酚的分离精制
针对煤气化副产物粗酚的组分和组成特点,设计了三塔和双塔两条连续减压精馏工艺.借助Aspen Plus软件对构建的分离工艺进行系统的模拟研究,物性方法采用NRTL模型.首先利用DSTWU模块简捷设计计算得到了塔板数、回流比和采出量等操作参数,对比得出适合该系统的分离工艺为双塔精馏.然后利用RadFRAC模块对设计结果进行严格模拟核算,最终得出双塔B1和B2的塔板数分别为29和31;进料塔板级数分别为15和16;回流比分别为2.87和2.44.在最佳操作条件下,所得产品质量分数分别为苯酚99.0％,对(间)甲酚86.1％,二甲酚96.5％.本研究结果可为粗酚的实际分离工艺设计和操作过程提供参数依据....
2020-07-10 14:39:05浏览：81
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某300MW机组循环水泵出力不足的诊断分析
某300 MW机组投产以来循环水流量不足,极大地影响了机组的经济性.通过试验诊断分析得到,循环水系统设计阻力小于实际值,导致按照设计阻力选型的循环水泵出力不足,使得循环水流量偏小,影响了机组运行的真空.根据循环水系统实际阻力特性,对循环水泵进行重新选型整体改造,取得了较好的效果,与改造前相比,供电煤耗降低1.174～1.200 g/(kW·h).据此,提出了循环水泵在设计选型时的注意事项....
2020-07-10 14:39:05浏览：50
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Characterization and performance of Cu/ZnO/Al2O3 catalysts prepared via decomposition of M(Cu,Zn)-am
Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M(Cu,Zn)-ammonia complexes (DMAC) at various temperatures.The catalysts were characterized in detail,including X-ray diffraction,N2 adsorption-desorption,N2O chemisorption,temperature-programmed reduction and evolved gas analyses.The influences of DMAC temperature,reaction temperature and specific Cu surface area on catalytic performance are investigated.It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts.The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol (212 g/(Lcat·h); T =513 K,p =3 MPa,S V =12000 h-1)....
2020-07-08 21:52:19浏览：43
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Simultaneous operation of dibenzothiophene hydrodesulfurization and methanol reforming reactions ove
In the current study simultaneous reactions of hydrodesulfurization (HDS) of dibenzothiophene (DBT) and reforming of methanol in a micro-autoclave reactor were studied over bi-metallic ( Co-Mo/Al2O3 and Ni-Mo/Al2O3 ) and tri-metallic ( Pd-Co-Mo/Al2O3 and Pd-Ni-Mo/Al2O3 ) catalyst systems which were prepared by incipient impregnation method.In situ hydrogen utilization and low Pd loadings were the major targets of this study.For comparison purpose,catalytic activity was separately determined for both the methanol reforming and HDS of DBT reactions as well.Ni based catalysts were confirmed with better activity than Co ones for both the reactions with Pd promoted ones ranking at the top i.e.Pd-Ni-Mo/Al2O3 ＞ Ni-Mo/Al2O3 ＞ Pd-Co-Mo/Al2O3＞ Co-Mo/Al2O3 where Pd-Ni-Mo/Al2O3 showed 91％ DBT conversion at 380 ℃ and 12 h reaction time.Some of the selected organic additives on catalytic activity were tested for their effect toward HDS reaction which was unique with close relation to their chemical nature.Reaction products were quantitatively and qualitatively analyzed via HPLC and GC-MS techniques respectively which helped in elucidating reaction mechanism....
2020-07-08 21:52:19浏览：50
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In-situ Synthesis of ZSM-5 Zeolite from Metakaolin/Spinel and Its Catalytic Performance on Methanol
ZSM-5 zeolite was in-situ synthesized from metakaolin or spinel by incorporating additional silica and alumina sources, respectively. The ZSM-5 zeolite was characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and N2 adsorption measurement. This supported zeolite was tested on the methanol to propylene (MTP) processes. Experimental results showed that the ZSM-5 zeolite exhibited high selectivity for propylene. The yield of propylene on ZSM-5 zeolite made from metakaolin was increased by 17.73%, while that on ZSM-5 zeolite made from spinel was raised by 9.90%, compared to that achieved with the commercial ZSM-5 zeolite. The significant increase in propylene production is probably due to the distinctive morphology of the ZSM-5 zeolite, which possessed a rough external surface covered with sphere-like particles and distribution of small crystals sized at around 400-500 nm. This morphology could help to generate more crystal defects so that more active centers could be exposed to the reaction mixture. In addition, the zeolite product had a gradient pore distribution and many medium Bronsted acid sites, both of which might also contribute to the increased propylene production....
2020-07-08 21:52:19浏览：62
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A Theoretical Study on Pyrolysis and Sensitivity of Energetic Compounds(Ⅴ)--Nitro Derivatives of Met
UHF-SCF-AM1 MO calculations were performed for two kinds of pyrolysis reactions of seven nitro derivatives of methylbenzene(homolysis reactions by the rupture of bond C-NO2 into radicals and isomerization reactions in the way of methyl H transferring to the ortho nitro O atom). The molecular geometries of the reactants, the transition states and the products of the fourteen reactions were fully optimized. The activation energies for these two kinds of reactions have been obtained. The results indicate that this category of compounds is more easily pyrolyzed by being initiated via isomerization reactions. A parallel relationship exists between the activation energy of the isomerization reactions and the impact sensitivity of the seven titled compounds....
2020-07-08 21:52:19浏览：74
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Assessment of Cu, Pb and Hg Contamination in Bottom Sediments Of Surface Water in XuZhou
Pollution of heavy metals Cu,Pb and Hg is assessed using geo-accumulation index in this paper. The result shows that the bottom sediments of surface water in Xuzhou is polluted by these heavy metals to deferent degrees, of which the Jinma River is the most serious, and then the Kuihe River, the abandoned Yellow River, and the Jinghang Canal. The Yunlong Lake has also been polluted by Hg. The three kinds of heavy metals in the order of concentration is Hg＞Cu＞Pb. The pollution degree and the type of element is closely related with industrial structure in Xuzhou....
2020-07-08 21:52:19浏览：58
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Soil Water Distribution and Irrigation Uniformity Under Alternative Furrow Irrigation
Field experiments were conducted to investigate the spatial-temporal distribution and the uni-formity of soil water under alternative furrow irrigation in spring maize field in Gansu Province. Resultsshowed that during the crop growing season, alternative drying and wetting furrows could incur crops to en-dure a water stress, thus the adsorptive ability of root system could be enhanced. As there was no zero fluxplane between irrigated furrows and non-irrigated furrows under alternative furrow irrigation, lateral infiltra-tion of water was obviously increased, thus decreasing the deep percolation. Compared with the conventionalirrigation, although the water consumption in alternative furrow irrigation was reduced, the uniformity of soilwater was not obviously affected....
2020-07-08 21:52:19浏览：67
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Study on the changes of water cycle and its impacts in the source region of the Yellow River
The water cycle in the source region of the Yellow River underwent great changes in the 1990s. The major features of the changes are as follows: the gauged runoff declined significantly while the precipitation increased slightly, and the runoff process was more concentrated on the flood season. Water balance analyses indicate that the pondage was kept in the status of negative equilibrium, causing eco-environmental problems. The runoff decrement is due to evaporation increment in this region. Studies show that the runoff process in this region is closely related to that of the other hydrological stations in the upper reaches. When the runoff declines in the source regions, the amount of water also declines in the whole upper reaches of the Yellow River, affecting the balance between water demand and supply. Meanwhile changes will take place in the water cycle of the river course system when the eco-environment deteriorates. The trend of water cycle change in the source region is that the runoff will keep declining with the increment of evaporation caused by temperature rise in the northwest of China in the 21st century. But the hydraulic engineering in the source region will help to mitigate the deterioration of local eco-environment system, though the impacts to the lower reaches of this project may not be the case....
2020-07-08 21:52:19浏览：61
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