【作者】 蔡川川；

【导师】 张明旭；

【作者基本信息】 安徽理工大学 ， 环境工程， 2013， 博士

【摘要】 炼焦煤是我国稀缺煤种,炼焦时残留在焦中的硫会使钢铁热脆；同时降低高炉生产能力；焦化过程产生的SO2腐蚀设备,污染环境；从而限制了高硫炼焦煤的使用。有效脱除炼焦煤含硫组份对充分利用炼焦煤资源、保护环境具有重大意义。对典型山西高硫炼焦煤开展研究,系统地分析煤样含硫组分赋存状态,各形态硫相对含量,确定有机硫赋存规律,筛选合适的含硫模型化合物；对典型高硫煤样及模型化合物开展介电性质测试,明确其微波响应频率；结合微观量子力学理论,计算含硫键基本性质,研究外加能量场对含硫组分脱除反应过程的影响；选择典型高硫煤种,开展微波脱硫试验,建立微波辐照条件与微波脱硫反应的匹配关系,为微波脱硫工业化试验开展提供技术支持和理论指导。论文具体的研究内容和取得的主要研究结果包括：1.典型高硫煤样含硫组分赋存状态：高硫煤种无机硫含量较低；有机硫赋存类型为硫醇硫醚类、噻吩类、(亚)砜类,以噻吩硫为主；随着密度增大,煤样中硫醇硫醚类含量下降,噻吩类含量呈增加趋势,(亚)砜类含量先降低后增大；通过硝酸酸洗和微波辐照处理,无机硫全部脱除,有机硫部分脱除,有机硫中硫醇硫醚类硫脱除效果最好,亚砜类次之,噻吩类硫脱除效果最差。2.典型高硫煤样介电性质测试结果：在0.2-18GHz频段范围,不同煤样在1.357GHz,2.581GHz、13.728GHz、15.8GHz等多个频率点出现介电响应峰值；高岭石含量增加使得ε’、ε”均增大,方解石对介电性质基本没有影响,石英介于二者之间；ε”随煤样粒度增大而降低；高密度煤样ε’高于低密度级煤样；ε”随煤样含水量增加迅速增大；高硫煤介电实部大于低硫煤。3.模型化合物介电性质测试结果：含硫模型化合物介电常数实部随频率变化趋势基本一致,在0-3GHz内出现吸收峰,3-8GHz范围保持平稳,10-18GHz出现若干明显的吸收峰；模型化合物对微波的最强吸收频段在9-11GHz；同时在0.5-2GHz频段,也有较为明显的损耗；模型化合物介电常数实部大小对比：二苯亚砜>二苯砜>二苯硫醚>二苯并噻吩>正十八硫醇；含硫模型化合物的加入提高了煤样的介电极化能力；含有硫键的模型化合物和不含硫键的模型化合物对微波有明显的响应差异。4.量子化学模拟计算：含硫模型化合物结构优化结果表明C-S键键长较长,脂肪族模型化合物C-S键键长大于芳香族模型化合物,处于环结构中的C-S键长度小于支链中的C-S键；处于噻吩环结构中的C-S键键级和C-C键键级相等,噻吩环中的C-S键键级大于非环中的C-S键键级；预测噻吩中C-S键更难断裂；模型化合物中的S原子处HOMO伸展较大,是给电子的位置,S原子易失去电子发生反应；过渡态搜索结果表明苯硫醇生成S自由基,然后S自由基结合H自由基生成H2S的路径能量势垒最小,相对于反应物的能量为57.652kcal/mol；加入外电场时,反应所需跨越能垒明显变小,且随电场强度增大能垒减小；考虑溶剂化作用时,反应所需能垒变小,随着溶剂介电常数值的增大,反应能量势垒变大。5.典型高硫煤种微波辐照实验：测试煤种粒度为1-3mmm脱硫效果较好；水分含量为10%时的脱硫率最高,频率840MHz和915MHz微波辐照脱硫效果明显高于2450MHz；微波辐照后,硫醇(醚)类硫相对百分含量降低明显,噻吩类硫相对含量增加；HAC和H2O2助剂配比为1：1的时候脱硫率达到最大值,随着氢氧化钠浓度的增加脱硫率不断上升,但上升速率逐渐降低。更多还原

【Abstract】 Coking coal is scarce in China. In the process of coking, the sulfur remained in coke could make the steel hot-short and reduce the production capacity of the blast furnace and the SO2produced in the process could corrode the equipments and pollute the environment, which thereby limit the use of high-sulfur coking coal. Therefore, the effective removal of sulfur-containing components in coking coal is of great significance for the full use of resources and environmental protection.The removal of sulfur in coal by microwave has been proved to be feasible both theoretically and technologically. It has the advantages including mild reaction conditions, less reaction time, easy to be controlled, high reaction yield and low damage to the organic matter of the coal. However, its reaction mechanism and optimal technological conditions have not been specifically identified yet, especially the optimum working frequency, the influencing factors and microcosmic mechanism of microwave desulfurization which are difficult to be ascertained need to be studied further.Researches have been carried out to study the typical Shanxi high-sulfur coking coal in this paper, including systematic analyzation of the occurrence state of the sulfur-containing components and the relative contents of various forms of sulfur in the coal samples, so as to ascertain the organic sulfur occurrence regularity and screen out suitable sulfur-containing model compounds. Dielectric properties tests have been done to the typical high-sulfur coal samples and the model compounds to identify its microwave frequency response. The influence of additional energy field on the removal process of sulfur-containing components has been studied on the basis of microscopic quantum-mechanical calculations. Microwave desulfurization experiments have been conducted to the high-sulfur coal in order to establish matching relationship between microwave irradiation conditions and microwave desulfurization reactions, which consequently provides technical support and theoretical guidance for the industrial tests of microwave desulfurization. The main research results include:1. The occurrence states of sulfur-containing components in typical high-sulfur coal: inorganic sulfur which is of low content is mainly composed of sulfates and organic sulfur is mainly composed of thiols thioethers, thiophenes, sulfones and sulfoxides, in which thiophenes are the majority. While the content of thiophenes is on the rise when the density of the coal samples increases, the content of thiols thioethers decreases and that of sulfoxides increases after showing a downward trend. After being dealt with nitric acid and microwave irradiation, all inorganic sulfur is removed while organic sulfur is partially removed, among which thiols thioethers have the best removal effect, sulfoxides comes second, and thiophenes is of the worst.2. The results of the dielectric properties tests on typical high-sulfur coal samples are listed as follows. In the frequency range of0.2-18GHz, dielectric response peaks of different coal samples appear in1.357GHz,2.581GHz,13.728GHz and15.8GHz, etc. The increasing content of Kaolinite results in the increase of both ε’ and ε". While quartz has less effect on the dielectric properties, calcite almost has on effect on it. ε" becomes lower when the particle size of coal samples increases, but it increases quickly along with the increase of moisture content in coal samples. The ε’ of high density coal sample is higher than that of low density coal sample. The microwave response of high-sulfur coal is superior to that of low sulfur coal.3. Along with the change of frequency, the permittivity real parts of the five sulfur-containing model compounds basically have consistent variation tendencies. Absorption peak occurs in the range of0-3GHz, and while the range of3-8GHz remains stable the range of10-18GHz receives a few obvious absorption peaks. The strongest absorption range of model compounds by microwave is9-11GHz and in the range of0.5-2GHz, model compounds have obvious loss of microwave. The size comparison of the permittivity real parts among the model compounds is as following:Diphenyl sulfoxide> Diphenyl sulfone> Diphenyl disulfide> Dibenzothiophene> N-octadecyl mercaptan. The addition of sulfur-containing model compounds improves the dielectric polarization ability of coal. The loss angle tangent of sulfur-containing model compounds and non-sulfur model compounds are quite different along with the change of frequency, which shows that sulfur bond has obvious response to the microwave.4. Analysis of quantum mechanics simulation software:the structural optimization results of sulfur-containing model compounds show that the C-S bond length is longer than other bonds. More specifically, the C-S bond length of aliphatic model compounds is longer than that of aromatic model compounds and the C-S bond length in the ring structure is shorter than that in branched chains. In the thiophene ring structure the C-S bond order is equal to the C-C bond order and meanwhile it is larger than that in the non-ring structure. The S atoms of the model compounds with comparatively large HOMO stretch take the giving electrons positions and they lose electrons easily and react with others. Transition state path analysis shows that H2S produced by microwave heating the S radicals generated by benzene thiol and the H radicals has the minimum energy barrier57.652kcal/mol, relative to the energy of reactants. As the strength of electric field increases, the required transition state energy barrier diminishes. Considering the solvation effect, transition state requires lower energy barrier and with the increase of the solvent’s permittivity, reaction energy barrier becomes larger.5. The results of microwave irradiation experiments on the typical high-sulfur coal are illustrated as follows. The coal with a particle size of1-3mm has the best desulfurization effect and the coal with a moisture content of10%possesses the maximum rate of desulfurization. The microwave irradiation desulfurization effects of840MHz and915MHz are significantly higher than that of2450MHz. After being irradiated by microwave, the relative content of mercaptan (sulfide) sulfur decreases obviously while that of thiophene sulfur increases. The desulfurization rate reaches the maximum when the ratio of HAC and H2O2additives is1:1. The desulfurization rate is constantly on the rise along with the increase of the concentration of sodium hydroxide, but the rising rate gradually decreases.更多还原