褐煤地下气化特性的实验研究

分别以富氧和富氧-水蒸气为气化介质,进行了大雁褐煤的地下气化模型实验.研究了鼓风量和汽氧比对煤气组成、气化稳定性以及煤层气化速率的影响,并进行了富氧-水蒸气地下气化过程的物料衡算.实验结果表明,通过采取合适的气化参数,大雁褐煤的地下气化过程可以稳定进行.     

褐煤地下气化制氢工艺的研究

进行了大雁褐煤纯氧、纯氧-水蒸气和空气-水蒸气两阶段地下气化制氢工艺模型实验;研究了鼓氧量及汽氧比对煤气中的氢含量、气化过程稳定性的影响。实验结果表明,褐煤地下气化初期纯氧气化可以获得含氢量在40％以上煤气,鼓氧量会影响煤气中的含氢量和热值;富氧-水蒸气气化也可以获得含氢量在40％以上煤气,汽氧比影响煤气中的含氢量和各组分含量,实验条件下适宜的汽氧比范围为1:(1.5～2);两阶段气化第二阶段可获得富含氢的煤气,但产量较小。因此,褐煤地下气化可稳定生产高含氢的煤气,该煤气在地面处理后可作为提取纯氢的原料气。     

富氧连续气化技术在我国的应用及发展

介绍了富氧连续气化技术的原理和工艺流程,并论述了富氧连续气化技术的优缺点。指出了我国富氧连续气化技术存在的问题以及目前我国一些企业富氧连续气化技术的发展现状。建议国内企业,虽然富氧连续气化技术还存在很多问题,但是不能固步自封,应在现有条件基础上改良设备、采用新技术、新工艺,以促进富氧连续气化技术的发展。     

新河烟煤地下气化模型

为了探索烟煤地下气化过程的基本规律,为新河“煤炭地下气化发电示范工程”制定合理的工艺参数,测定了新河烟煤反应活性,并进行了富氧-水蒸气地下气化模型实验;研究了不同工艺条件下,出口煤气有效组分含量、热值的变化规律.实验结果表明,气化初期因煤层中含水,纯氧直接气化,可获得合格的煤气;在保持汽氧比在1.5∶1～2∶1之间时,新河烟煤采用富氧-水蒸气正向供风、辅助孔供风和反向供风连续气化可获得有效气体组分在70%、热值在10 MJ·m^-3左右的煤气;新河烟煤的产气率平均为1950 m³·t^-1,煤层气化率可达到74.6%.     

工业燃料煤气气化技术的探讨与分析

简要介绍和对比了煤化一和IGCC电站配套的几种煤气化技术,分析了工业燃料煤气对气化技术的要求和现有工业燃料煤气气化技术的现状,并在此基础上对气流床、流化床和型煤气化等粉煤气化技术,以及富氧气化技术在工业燃料煤气方面的应用进行了探讨分析,同时就高温空气气化技术进行了探讨。指出应该借鉴煤化工和IGCCCE站配套的煤气化技术,在优化现有技术的前提下,开发适于供应工业燃料煤气的气化技术。     

型煤移动床富氧连续气化试验运行分析

以福建无烟粉煤和粘结剂成型制得型煤,用富氧空气为气化剂,在3 m型煤移动床富氧连续气化炉上进行了工业化气化试验。结果表明,型煤移动床富氧连续气化,可以实现安全稳定可靠气化运行,制出合格半水煤气,气质能满足合成氨、甲醇生产,可代替间歇式移动床气化。气化火用效率为67.2%,气化效果较好,有显著的节能减排效益,良好的推广应用前景。但有效气体成分偏低,CO2含量比较高。可采用高活性的晋城无烟粉煤生产的型煤气化或通过添加剂提高煤灰熔融温度、气化温度等措施,降低煤气中CO2含量。     

富氧连续气化工艺的利与弊

论述了富氧连续气化的工艺流程和技术优缺点，并对富氧连续气化技术的选择提出了建议。     

富氧连续气化技术在沾化公司的应用探讨

介绍型煤富氧连续气化技术,并对型煤富氧连续气化与间歇气化技术进行了比较。以云南煤化集团沾化分公司为例,提出型煤间歇气化改型煤富氧连续气化技术改造方案,并对其经济效益及环保效益进行分析。     

富氧连续煤气化技术

介绍了富氧连续煤气化工艺流程,通过实例计算并与空气间歇气化方式对比表明,富氧连续气化技术单炉生产能力大,蒸汽分解率高,热利用率高,设备台数少。建议企业结合自身实际情况确定是否选用富氧连续气化技术。     

鹤壁烟煤地下气化的污染研究

通过自行研制的煤炭地下气化模拟试验系统,采用富氧空气/水蒸气两阶段气化工艺进行鹤壁烟煤地下气化模型试验,用地下水浸泡气化残焦。对气化管道煤气冷凝水、煤气洗涤水和残焦浸出液中的挥发酚、TOC、COD和氨氮进行检测,考察煤炭地下气化对地下水可能造成的污染。结果发现,煤气冷凝水中的挥发酚、TOC和COD均大于煤气洗涤水的;水蒸气气化阶段氨氮浓度最高,可达497.52 mg/L;残焦浸出液中的挥发酚、COD和氨氮的最大值均低于污水排放允许最高范围内。     

CFD analysis of hydrodynamic, heat transfer and reaction of three phase riser reactor

Catalytic cracking reaction and vaporization of gas oil droplets have significant effects on the gas solid mixture hydrodynamic and heat transfer phenomena in a fluid catalytic cracking (FCC) riser reactor. A three-dimensional computational fluid dynamic (CFD) model of the reactor has been developed considering three phase hydrodynamics, cracking reactions, heat and mass transfer as well as evaporation of the feed droplets into a gas solid flow. A hybrid Eulerian-Lagrangian method was applied to numerically simulate the vaporization of gas oil droplets and catalytic reactions in the gas-solid fluidized bed. The distributions of volume fraction of each phase, gas and catalyst velocities, gas and particle temperatures as well as gas oil vapor species were computed assuming six lump kinetic reactions in the gas phase. The developed model is capable of predicting coke formation and its effect on catalyst activity reduction. In this research, the catalyst deactivation coefficient was modeled as a function of catalyst particle residence time, in order to investigate the effects of catalyst deactivation on gas oil and gasoline concentrations along the reactor length. The simulation results showed that droplet vaporization and catalytic cracking reactions drastically impact riser hydrodynamics and heat transfer.     

载气蒸发法及其在工业中的应用

重点介绍载气蒸发法的原理和特点，并阐明了在气液两相界面汽化热阶效应作用下，该法增强传热的机理，还介绍了该技术在工业上的应用情况。     

VAPORIZATION OF ELEMENTAL MERCURY FROM MOLTEN LEAD AT LOW CONCENTRATIONS

Experiments were conducted to measure the rate of vaporization of elemental mercury from molten lead to provide a basis for estimating radiological source terms for the APT (Accelerator Production of Tritium project) lead blanket. These data also have application to other accelerator targets in which mercury may be created by proton spallation in lead. Molten pools of lead with from 0.01% to 0.10% mercury were prepared under inert conditions. Experiments were conducted which varied in duration from several hours to as long as a month to measure the mercury vaporization from the lead pools. The melt pools and gas atmospheres were controlled at 340 degrees C during the tests, above the melting temperature of lead. Parameters which were varied in the tests included the mercury concentrations, gas flow rates over the melt, circulation in the melts, gas atmosphere compositions and the addition of aluminum to the melts. The vaporization of mercury was found to scale roughly linearly with the concentration of mercury in the pool. Variations in the gas flow rates were not found to have any effect on the mass transfer, however circulation of the melt by a submerged stirrer did enhance the mercury vaporization rate. The rate of mercury vaporization under a high-purity argon atmosphere was found to exceed that for an air atmosphere by as much as a factor of from ten to 20; the causal factor in this variation was the formation of an oxide layer over the melt pool with the air atmosphere which retarded mass transfer across the melt-atmosphere interface. Aluminum was introduced into the melt to investigate its effect upon the mercury vaporization rate. No effect was observed for a case under a high-purity argon atmosphere, which suggests that there are no chemical effects of the aluminum on the vaporization kinetics. With an air atmosphere, the presence of aluminum in the melt reduced the mercury vaporization by a factor of six in comparison to the identical test but without aluminum, suggesting that aluminum in the lead/ mercury melt retards the vaporization of mercury by creating a surface oxide layer in addition to the lead-oxide layer or by changing the character of the lead-oxide layer, thereby increasing the mass transfer resistance.     

Vaporization of elemental mercury from molten lead at low concentrations

Experiments were conducted to measure the rate of vaporization of elemental mercury from molten lead to provide a basis for estimating radiological source terms for the APT (Accelerator Production of Tritium project) lead blanket. These data also have application to other accelerator targets in which mercury may be created by proton spallation in lead. Molten pools of lead with from 0.01% to 0.10% mercury were prepared under inert conditions. Experiments were conducted which varied in duration from several hours to as long as a month to measure the mercury vaporization from the lead pools. The melt pools and gas atmospheres were controlled at 340 degrees C during the tests, above the melting temperature of lead. Parameters which were varied in the tests included the mercury concentrations, gas flow rates over the melt, circulation in the melts, gas atmosphere compositions and the addition of aluminum to the melts. The vaporization of mercury was found to scale roughly linearly with the concentration of mercury in the pool. Variations in the gas flow rates were not found to have any effect on the mass transfer, however circulation of the melt by a submerged stirrer did enhance the mercury vaporization rate. The rate of mercury vaporization under a high-purity argon atmosphere was found to exceed that for an air atmosphere by as much as a factor of from ten to 20; the causal factor in this variation was the formation of an oxide layer over the melt pool with the air atmosphere which retarded mass transfer across the melt-atmosphere interface. Aluminum was introduced into the melt to investigate its effect upon the mercury vaporization rate. No effect was observed for a case under a high-purity argon atmosphere, which suggests that there are no chemical effects of the aluminum on the vaporization kinetics. With an air atmosphere, the presence of aluminum in the melt reduced the mercury vaporization by a factor of six in comparison to the identical test but without aluminum, suggesting that aluminum in the lead/ mercury melt retards the vaporization of mercury by creating a surface oxide layer in addition to the lead-oxide layer or by changing the character of the lead-oxide layer, thereby increasing the mass transfer resistance.     

A method for measuring the kinetics of organically associated inorganic contaminant vaporization during coal combustion

A novel method is presented for the direct measurement of kinetic parameters under conditions that simulate the vaporization of inorganic material during coal combustion. This method will ultimately be used to generate key physical property data necessary to model and assess the vaporization behavior of trace elements (TEs) during coal combustion. The method uses a graphite furnace atomic absorption spectrometer (GFAAS) as the experimental platform for vaporization measurements for temperatures up to 2800 K. The method was used to model vaporization during coal pyrolysis for one of the three key contaminant domains: organically associated material. Significant testing was conducted for selected TEs under varied instrumental operational conditions that could affect activation energies, such as GFAAS ashing and atomization temperatures, TE concentration, and carrier gas flow rate. The vaporization activation energies determined were found to be independent of these operating conditions despite a significant difference in the degree of analyte vaporization observed at varied ashing temperatures.     

REACTION ENHANCED VAPORIZATION OF MOLTEN SALT

Vaporization of molten salts results in serious problems in the operation of many combustion systems. Salt vaporization of special importance in the burning of kraft black liquor, where combustion occurs in a molten Na₂S/Na₂CO₃ environment.

In this paper, it is shown that the vaporization of alkali carbonate during air oxidation of Na₂S/Na₂CO₃ results from Na oxidation in the gas phase. Oxidation of Na in the gas phase significantly lowers the partial pressure of Na. Since the driving force for vaporization is the difference between the equilibrium vapor pressure of Na at the gas-melt interface and the partial pressure of Na in the gas phase, this reduction in partial pressure of Na significantly increases Na vaporization rates and allows fuming to proceed with only mild reducing conditions in the melt.     

REACTION ENHANCED VAPORIZATION OF MOLTEN SALT

Vaporization of molten salts results in serious problems in the operation of many combustion systems. Salt vaporization of special importance in the burning of kraft black liquor, where combustion occurs in a molten Na₂S/Na₂CO₃ environment.

In this paper, it is shown that the vaporization of alkali carbonate during air oxidation of Na₂S/Na₂CO₃ results from Na oxidation in the gas phase. Oxidation of Na in the gas phase significantly lowers the partial pressure of Na. Since the driving force for vaporization is the difference between the equilibrium vapor pressure of Na at the gas-melt interface and the partial pressure of Na in the gas phase, this reduction in partial pressure of Na significantly increases Na vaporization rates and allows fuming to proceed with only mild reducing conditions in the melt.     

A comparative study of two heating procedures in the physical refining of edible oils

Two mixtures of refined sunflower seed oil, one with oleic acid and the other with olive oil distillates from a laboratory plant, were physically refined using nitrogen as stripping gas in a discontinuous deodorization pilot-plant scale installation (30-L capacity). Two heating procedures were tested: one using independent electrical heating for the oil and the gas distillates so as to maintain the same temperature in both, and another in which only the oil was heated and controlled, resulting in a difference in temperatures in the oil and the gas distillates. Two different oil temperature values and three nitrogen flow rates were also assayed. The statistical technique of blocking with paired comparisons was used to analyze the results. These results showed that maintaining the same temperature in the oil and gas distillates had a positive effect on free fatty acid distillation rate and vaporization efficiency. Oil temperature and nitrogen flow rate also influenced some of the aforementioned responses.     

原料油汽化特性对催化裂化反应结焦过程影响的CFD模拟

为考察原料油汽化特性影响,在一套百万吨级工业FCC提升管中,基于多相欧拉模型耦合EMMS曳力和传质、油滴汽化和十二集总反应动力学模型,采用三维CFD模拟研究气液固三相流动、汽化、反应、结焦的复杂过程,新开发结焦预测模型定量预测结焦状况,对比研究不同原料油雾化液滴粒径和起始汽化温度下各相和反应组分浓度场、温度场分布和结焦程度。结果表明,模拟方法可较准确预测汽化、反应生焦和结焦过程,不同雾化液滴粒径和起始汽化温度通过流场分布和汽化快慢影响液相油滴汽化率和反应转化率;合适液滴粒径(60 μm)和起始汽化温度(654 K)可提升轻油、汽油、液化石油气目标产品收率并改善结焦程度。     

原料油汽化特性对催化裂化反应结焦过程影响的CFD模拟

为考察原料油汽化特性影响,在一套百万吨级工业FCC提升管中,基于多相欧拉模型耦合EMMS曳力和传质、油滴汽化和十二集总反应动力学模型,采用三维CFD模拟研究气液固三相流动、汽化、反应、结焦的复杂过程,新开发结焦预测模型定量预测结焦状况,对比研究不同原料油雾化液滴粒径和起始汽化温度下各相和反应组分浓度场、温度场分布和结焦程度。结果表明,模拟方法可较准确预测汽化、反应生焦和结焦过程,不同雾化液滴粒径和起始汽化温度通过流场分布和汽化快慢影响液相油滴汽化率和反应转化率;合适液滴粒径(60 μm)和起始汽化温度(654 K)可提升轻油、汽油、液化石油气目标产品收率并改善结焦程度。