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1、西安科技大学 硕士学位论文 低变质煤热解-气化耦合工艺模拟优化研究 姓名：秦丽娜 申请学位级别：硕士 专业：矿物加工工程 指导教师：李建伟 论文题目：低变质煤热解-气化耦合工艺模拟优化研究 专业：矿物加工工程 硕 士 生：秦丽娜（签名） 指导教师：李建伟（签名） 摘要 煤炭是我国的主要一次能源，其中低变质的褐煤、长焰煤、不粘煤、弱粘煤等资源 丰富且质量较好，近年来开采比重日益增大。针对低变质煤挥发份含量高的特点而提出 的煤炭分级转化技术，根据煤在不同阶段反应特性不同的特点，实施煤热解、气化和燃 烧分级转化，可提高煤炭利用率，简化煤炭气化技术，减小投资降低成本，并能有效解 决煤中污染物的脱除问题
2、。 本文借鉴“联合热转化技术”思想，在对国内外主要热解和部分气化工艺研究分析 的基础上，提出低变质煤热解-部分气化耦合工艺，并对该工艺进行了模拟研究与分析， 为进一步的具体技术开发和操作控制提供了参考和指导。 通过对煤热解反应动力学分析，并基于分布活化能模型 DAEM，建立了集总反应动 力学模型来表示煤炭热解过程，确定了可以预测热解产物组成、分布与热解终温和升温 速率关系的动力学方程。研究表明，随热解温度升高，各种挥发份产物析出率越接近最 大产率，半焦 C 含量增加，但产率下降，H、O、N 和 S 等元素降低。因此，升温有利 于提高半焦脱硫、脱氮率。600左右，除 H2外的大部分挥发份基本析出
3、，半焦元素变 化幅度减小。热解终温较低且一定时，较慢的升温速率有利于各热解挥发份最大限度的 析出。分析结果显示，将热解终温控制在 550，升温速率 10/min 左右有利于热解挥 发份完全析出。 运用 Aspen Plus 化工流程模拟软件，建立了将煤干馏热解和半焦部分气化相结合的 两段气化模拟模型。结果表明，建立的气化炉模型能对本文提出的两段工艺进行较准确 地模拟。热解段得焦油 12.23%，半焦收率为 65.11%，基本符合煤炭热解结果。调节分 割器分割率为 0.53:0.47 时，可使热解段湿煤预热至指定温度 110。通过对气化段做灵 敏度分析可得，当氧气煤比（O2/C）为 0.33，蒸
4、汽煤比（H2O/C）为 0.20，或者氧气煤 比 0.356，蒸汽煤比 0.25 时，气化炉温度可维持在 900左右，且冷煤气效率最高。 关 键 词：热解；部分气化；ASPEN PLUS；分布活化能模型 研究类型：应用研究 SubjectSubjectSubjectSubject: : : : StudyStudyStudyStudy onononon SimulationSimulationSimulationSimulation andandandand OptimizationOptimizationOptimizationOptimizationofofofof LowLowLowLo
5、w MetamorphicMetamorphicMetamorphicMetamorphic CoalCoalCoalCoal Pyrolysis-gasificationPyrolysis-gasificationPyrolysis-gasificationPyrolysis-gasification CouplingCouplingCouplingCouplingTechnologyTechnologyTechnologyTechnology SpecialtySpecialtySpecialtySpecialty : : : : MineralMineralMineralMineral
6、ProcessProcessProcessProcess EngineeringEngineeringEngineeringEngineering NameNameNameName: : : : QinQinQinQin LinaLinaLinaLina(Signature)(Signature)(Signature)(Signature) Instructor:Instructor:Instructor:Instructor: LiLiLiLi JianweiJianweiJianweiJianwei(Signature)(Signature)(Signature)(Signature) A
7、BSTRACTABSTRACTABSTRACTABSTRACT Coal is the primary energy source of China, in which low metamorphic coal including lignite, long flame coal, non-caking coal and light sticky coal are abundant and have high quality, and the proportion of mining are increaseing improved. Coal staged conversion which
8、was proposed considering that low metamorphic coal had the character of high volatile matter, according to the different reaction features of different coal in different conversion period, implement classification conversion about pyrolysis, gasification and combustion. This technology can raise coa
9、l utilization, simplify gasification, reduce the investment and cost, and effectively solve the problem of removal of contaminants of coal. Reference to the “combined thermal-conversion technologies”, based on the analysis and study on pyrolysis and partial gasification technology of domestic and ov
10、ersea, the thesis put forward the low metamorphic coal pyroglysis-partial gasification coupling technology, and this process was simulated and analyzed to provide reference and guidance for the further development of specific method and operational control. Through the analysis of coal pyrolysis rea
11、ction dynamics, based on distribution activation energy model (DAEM), the lumped reaction kinetics model was established to represent the pyrolysis process, and kinetics equations which can estimate the relation among the composition and distribution of pyrolytic products and final pyrolysis tempera
12、ture and heating rate were determined. The research showed that the emission rate of volatile matter approached the ultimate production rate with the rising of final pyrolysis temperature, while semi-coke yield reduced, of which C content increased and the others including H, N, O and S content decr
13、eased. Therefore, the rising of final temperature favored the desulfurization and denitrification of semi-coke. The most volatile except H2basically released and elements change range of semi-coke decreased at 600. When pyrolysis temperature remained constant, slow heating was beneficial to the full
14、 emission of volatile matter. Analysis results showed that controlling the temperature at 550 and heating rate of 10/min volatile matter can wholly release. Based on ASPEN PLUS, the simulation method of the two-stage gasification technology integrated with pyrolysis model of coal and partial gasific
15、ation of semi-coke was presented. The results showed that the established gasifier model can accurately simulate the two-stage technology which the thesis put forward. Tar yield of the pyrolysis-stage was 12.23%, and semi-coke yield was 65.11%. By regulating the segmentation rate of splitter at 0.53
16、:0.47, the wet coal can be preheated to the specified temperature at 110. Finally, the gasification-stage was optimized based on performance parameters adjustment and sensitivity analysis. When ratio of oxygen to coal (O2/C) was 0.33 and ratio of steam to coal (H2O/C) was 0.2, or O2/C and H2O/C were 0.356 and 0.25 respectively, the temperature of gasifier can maintain at 900 and the cold gas efficiency was highest. KeyKeyKeyKeyWordsWordsWordsWords : : : :PyrolysisPartial gasificatio
