共查询到18条相似文献,搜索用时 140 毫秒
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以硫酸渣和煤粉为主要原料,对硫酸渣含碳球团进行焙烧,考察焙烧时间、焙烧温度、配碳量对球团金属化率的影响,确定了最佳工艺参数,即焙烧温度为1 225℃、焙烧时间15 min、(C)/(O)为1.2时,球团金属化率可达92.5%,此工艺参数满足转底炉高效还原的特点,适用于转底炉工艺。 相似文献
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Chemical-looping combustion (CLC) is a new combustion technology with inherent separation of CO2. Most of the previous investigations on CLC of solid fuels were conducted under atmospheric pressure. A pressurized CLC combined cycle (PCLC-CC) system is proposed as a promising coal combustion technology with potential higher system efficiency, higher fuel conversion, and lower cost for CO2 sequestration. In this study pressurized CLC of coal with Companhia Valedo Rio Doce (CVRD) iron ore was investigated in a laboratory fixed bed reactor. CVRD iron ore particles were exposed alternately to reduction by 0.4 g of Chinese Xuzhou bituminous coal gasified with 87.2% steam/N2 mixture and oxidation with 5% O2 in N2 at 970 °C. The operating pressure was varied between 0.1 MPa and 0.6 MPa. First, control experiments of steam coal gasification over quartz sand were performed. H2 and CO2 are the major components of the gasification products, and the operating pressure influences the gas composition. Higher concentrations of CO2 and lower fractions of CO, CH4, and H2 during the reduction process with CVRD iron ore was achieved under higher pressures. The effects of pressure on the coal gasification rate in the presence of the oxygen carrier were different for pyrolysis and char gasification. The pressurized condition suppresses the initial coal pyrolysis process while it also enhances coal char gasification and reduction with iron ore in steam, and thus improves the overall reaction rate of CLC. The oxidation rates and variation of oxygen carrier conversion are higher at elevated pressures reflecting higher reduction level in the previous reduction period. Scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM-EDX) analyses show that particles become porous after experiments but maintain structure and size after several cycles. Agglomeration was not observed in this study. An EDX analysis demonstrates that there is very little coal ash deposited on the oxygen carrier particles but no appreciable crystalline phases change as verified by X-ray diffraction (XRD) analysis. Overall, the limited pressurized CLC experiments carried out in the present work suggest that PCLC of coal is promising and further investigations are necessary. 相似文献
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Zixu Yang Junhao Hu Yang Li Yingquan Chen Kezhen Qian Haiping Yang Hanping Chen 《能源学会志》2019,92(2):391-402
Hydrogen-rich gas production from catalytic steam gasification of coal was investigated in the presence of iron ore in a vertical fixed bed reactor. The addition of iron ore significantly promoted the H2 yields. The effects of operation parameters (upper zone temperature, lower zone temperature, steam concentration, and iron to coal ratio) on the yield of selected gaseous products (H2 and CO) during catalytic steam gasification, were studied using Taguchi method. The results of signal-to-noise ratio indicated that steam concentration and iron to coal ratio were the most important parameters in determining the yield of H2 and CO, respectively. Semi-quantification X-ray diffraction analysis of iron ores indicated that increase in steam concentration intensified the oxidization of low valence iron compounds to Fe3O4. In addition, formation of Fe3O4 was also favored with increasing reaction temperatures (600 °C–900 °C). However, the formation of Fe3O4 was inhibited at higher reaction temperature (1000 °C) due to the destruction of porous structures of the iron ore. 相似文献
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本文通过矿粉、粉煤灰在不同研磨体级配情况下研磨产品的比重、比表面积、标准稠度需水量、水泥胶砂强度等性能参数的测定,得出了它们的变化规律,继而分析和探讨了不同研磨体级配对磨细矿渣和粉煤灰掺合料性能的影响. 相似文献
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The production-history projection method of the authors is refined to determine the earliest date at which reasonably well determined depletion parameters can be ascertained. The method is applied to the United States production data for silver, crude oil, natural gas, coal, iron ore and uranium ore. 相似文献
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运行参数对锅炉煤粉着火燃烧和飞灰含碳量影响的数值研究 总被引:6,自引:1,他引:6
为了达到锅炉的优化运行以保证煤粉气流及时着火和充分燃尽,采用IPSA两相流动模型和煤粉燃烧综合模型,在不同的一次风率和煤粉细度的工况下,对1台350MW锅炉煤粉燃烧过程进行了数值模拟,得出了炉内燃烧器区域以及出口处烟气温度场和燃烧产物的组分浓度分布。分析了一次风率和煤粉细度对煤粉着火燃烧和飞灰含碳量的影响规律,并确定了优化的运行参数。结果表明:一次风率对煤粉气流的着火影响较大,而对出口处烟气温度、氧量以及飞灰含碳量影响较小。煤粉细度对煤粉气流的着火、燃烧以及燃尽均有较大影响。图8表2参9 相似文献
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《International Journal of Hydrogen Energy》2020,45(56):31481-31493
In order to attain comprehensive utilization of hematite ore fines and reduce carbon dioxide emission, the flash reduction of hematite ore fines under hydrogen atmosphere is studied. The changes of phase composition at 1450 K–1800 K are investigated. A mathematical model is developed to accurately evaluate the reduction kinetic parameters of hematite ore fines based on experiment. The complex flash reduction is accurately described by considering the multiple reaction mechanisms, including hematite thermal decomposition, gas-solid reduction and gas-liquid reduction. The activation energies of the gas-solid reduction and gas-liquid reduction at high temperature are obtained as 223 kJ mol−1 and 180 kJ mol−1, respectively. The developed kinetic model can well describe and predict the flash reduction process of hematite ore fines. The effects of particle size and temperature on the flash reduction process, and the contributions of the thermal decomposition, gas-solid reduction and gas-liquid reduction to the overall reaction process are clarified. 相似文献
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Hanquan Zhang Zeqiang Zhang Hong Yu 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2019,41(1):47-64
Fe–P separation and the behaviors of Fe and P in separation process of high-phosphorus oolitic hematite ore from western Hubei province in China were studied. Various parameters, including reducing temperature and time, dosage of the pulverized coal, grinding fineness of magnetic separation feed, magnetic field intensity and grinding fineness of flotation feed were investigated. Experimental results show that the iron concentrate with total iron grade of 61.78% and phosphorus content of 0.23% was obtained from an oolitic hematite ore containing 47.71% iron and 0.874% phosphorus by magnetization roasting-magnetic separation-reverse flotation separation process under the proper conditions. In the magnetization roasting process, the Fe and P grade was rising by 1.30% and 11.49%, respectively; the forms of Fe and P are oolite hematite (magnetite) and collophanite which mainly distributed inside oolite structure and a small portion being distributed in other shapes. In the magnetic separation process, the Fe is from 48.33% to 58.52%, and P grade was slipped to 0.70% from 0.97%, however, the forms of Fe and P have no change compared with the roasted ore. In the reverse flotation separation process, Fe is from 58.52% to 61.78%, phosphorus is from 0.70% to 0.23%, the flotation concentrate mainly contained fine iron mineral and phosphorus is finely disseminated inside the iron mineral. 相似文献