低阶煤基化学品分级联产系统的碳氢转化规律与能量利用的研究

发布时间：2018-01-18 10:24

本文关键词：低阶煤基化学品分级联产系统的碳氢转化规律与能量利用的研究　出处：《北京化工大学》2015年博士论文　论文类型：学位论文

【摘要】：在今后比较长的时期内,煤炭仍然我们国家的主要能源来源。随着高阶煤煤炭资源的开采,中低阶煤高效转化和清洁利用的问题越来越突出。同时,解决该问题也是确保本国能源安全的一个重要举措。本文依托国家重点基础研究发展计划(973计划2011CB201306)的资助,开展低阶煤基化学品与清洁燃料分级联产系统的碳氢转化规律与能量利用原理的创新研究。主要研究内容如下：阐述了化学品分级联产系统的物质转化与能量利用原理。从低阶煤及其附属化学品的热物性、化学平衡和碳排放的角度,描述了煤转化过程中碳氢化合物基化学品生产过程的物质转化原理。针对于纯化工多联产系统的特征,提出了化学品分级联产系统的新认识,以及该系统评价方法和核心指标,并以此揭示化学品分级联产系统的物质转化原理与能量利用规律。同时,针对煤转化工艺流程结构的复杂性,本研究提出了分层次热集成的方法,以提高热集成方案的可行性。集成多个参数指标,揭示了低阶煤基煤气、半焦和轻质油联产工艺的能量利用特征。联立煤的低温热解工艺和煤焦油的常减压蒸馏工艺,构建了低阶煤基联产煤气、半焦和轻质油的工艺系统,并开展模型化研究。计算表明,湿度约为40%的褐煤经热解后,半焦、煤气和轻质油的产率分别可达到42.30%、8.47%和4.10%。集成了产品产率-能耗/(?)损-过程单元三个参数,分析联产系统中物质转化规律和能量利用情况。在完成上述工艺条件和物质转化的目标下,联产工艺中能耗和(?)失最大的为干燥单元的,其次是热解单元。本文通过集成物流品位、公用工程温度和过程单元三个参数,阐述联产系统中的能量匹配与转化原理。联产工艺中各单元的能耗与(?)损按照工艺顺序逐渐降低,部分产品的品位随着过程的进行逐渐升高。另外,干煤和焦油等化学品品位相对于原煤品位的上升是以单元过程消耗能量和支付(?)损为代价的。不同单元所需要的热冷公用工程的品位不同,各单元产出物流的化学品品位也不同。利用分层次热集成的方法开展了热解联产系统的热集成研究。通过上述联产系统的能量分析可以发现,低阶煤基热解联产系统具有较大的节能潜力。按照分层次热集成的方法,对低阶煤基热解联产系统进行了四个层次的分层次热集成。按照分层次热集成的判据,选择第三层次热集成的方案作为低阶煤热解联产系统的热集成方案,此时系统的总能耗为382.8kW,节能率为39.8%。该案例的研究表明,分层次热集成的方法适用于工艺结构比较复杂的系统,它从技术上较为全面的解决了传统热集成方法获得的节能方案在实际生产中可行性较低的问题。研究了炉气蒸汽重整的化学反应机理,并探讨工艺参数对目标要求的影响。在联产系统中,将氧热法电石炉气和热解气混合后进行蒸汽重整,根据独立反应方程的热力学特征提出了炉气蒸汽重整制氢的化学反应机理,体系中的平衡组成由四个独立反应的正逆反应共同决定。结合反应机理分别分析了温度、压力和水汽比对CO和CH4转化率、H2选择性和反应能耗的影响。通过集成四幅二维图描述了H2产量、水汽比、压力、温度、反应能耗和产物中H2/CO摩尔比之间的关系。通过该方法可以基于后期电石炉气利用方案所要求的不同H2/CO的摩尔比确定电石炉气蒸汽重整制氢的工艺参数。基于化学品分级联产的新认识和构建原则,研究了较优的炉气分级联产方案。通过对比炉气基化学品的生产工艺特征和技术成熟性,确定了炉气联产系统的目标产品。综合考虑目标产品的生产流程特征,构建了四种炉气基甲醇、二甲醚和燃料油分级联产方案。按照纯化工分级联产系统的构建原则和以及系统的评价方法,对比分析了各方案的核心指标特性。初步认为方案一和四的流程结构要优于单产方案和其他联产方案的结构。最后,结合之前的研究构建了低阶煤基化学品分级联产系统的工艺流程,并进一步确定了炉气联产方案。着重分析了该系统的物质转化与能量利用规律,包括有效原子收率、能耗分布、碳排放和污染物。炉气利用方案对分级联产系统的碳氢转化与能量利用特征的影响较大,后期应考虑炉气利用子系统的优化工作。
[Abstract]:In the future more long period of time, coal is still the main source of our country. With the high rank coal resources exploitation, low rank coal conversion efficiency and clean utilization problems become more and more prominent. At the same time, an important measure to solve the problem is to ensure its energy security. Based on the national key basic research and development plan (973 2011CB201306) funding, to carry out low rank coal based chemicals and clean fuel grade cogeneration system of hydrocarbon conversion principle of innovation research and utilization of energy. The main research contents are as follows: This paper describes the transformation and utilization of energy principle of chemicals cogeneration system. From the classification of thermophysical properties of low rank coal and its subsidiary chemicals, chemical balance and carbon emissions, coal conversion process of hydrocarbon based chemicals in the production process of material transformation principle is described. According to the pure chemical polygeneration system The characteristics, the paper puts forward a new idea of chemical classification of the combined system, and the system evaluation method and core indicators, and to reveal the chemical substance transformation principle classification system and energy law. At the same time, according to the complexity of coal conversion process structure, this study proposes a method of layered heat integration, in order to improve the feasibility heat integration. Integration of multiple parameters, reveals the low rank coal based gas, using the energy characteristics of production technology of semi coke and light oil. The distillation process of low temperature pyrolysis process of coal tar and simultaneous coal, construction of low rank coal gas based cogeneration system, the process of semi coke and light oil. And carry out the research model. The results show that the humidity was about 40% of Lignite by pyrolysis, char, gas and light oil yield could reach 42.30%, 8.47% and 4.10%. integrated product yield - energy - loss / (?) Unit three parameters, analyze the rules and energy generation system. The transformation after the completion of the process conditions and material conversion goals, energy consumption and production technology in (?) the biggest loss for the drying unit, followed by pyrolysis unit. In this paper, through the integration of material flow grade, utilities temperature and process unit three parameters, this generation system, energy and transformation principle. Each unit of production process in energy consumption and (?) loss according to the process order gradually reduced, product grade gradually increased with the process. In addition, dry coal tar and other chemicals to increase coal grade grade is in unit process energy consumption and pay the cost of the loss (?). The need of different units of hot and cold utilities of different grade, the output of each unit of chemical logistics grade is also different. By using the method of hierarchical thermal integration of open The study on pyrolysis heat integrated cogeneration system. The cogeneration system of energy analysis can be found in low rank coal pyrolysis based cogeneration system has great energy-saving potential. In accordance with the method of hierarchical thermal integration, based on low rank coal pyrolysis cogeneration system was integrated thermal stratified four levels. According to the thermal stratification integrated criterion, third levels of heat integration scheme as heat integration of low rank coal pyrolysis cogeneration system, the total energy consumption of the system is 382.8kW, energy-saving rate of the case study of 39.8%. showed that the method of layered heat integrated application system is more complicated in process structure, it is technically more comprehensive solution such schemes have traditional heat integration method is feasible in actual production. The problems of low furnace gas steam reforming chemical reaction mechanism, and discusses the process parameters on the objectives and requirements. Ring. In cogeneration system, the thermal process of furnace gas and oxygen gas mixture by steam reforming, the chemical reaction mechanism of furnace gas steam reforming was put forward according to the thermodynamic characteristics of independent reaction equation, system balance reaction consists of four independent reactions were decided by combining the analysis of the temperature. The reaction mechanism, pressure and moisture ratio of CO and CH4 conversion, H2 selectivity and reaction effect of energy consumption. By integrating the four 2D graph describes the H2 yield, moisture ratio, pressure, temperature, H2/CO molar ratio of the reaction between energy consumption and product. The method required post furnace gas utilization scheme based on the different molar ratio of H2/CO to determine the process parameters of calcium carbide furnace gas steam reforming. Based on the new understanding of chemical classification and construction principles of cogeneration, furnace gas better classification scheme. Through the comparison of production Furnace gas based chemical production process characteristics and mature technology, the furnace gas cogeneration system of target products. The comprehensive production process considering the characteristics of the targeted products and constructed four kinds of furnace gas based methanol, dimethyl ether and two fuel oil generation program. According to the evaluation classification principles and methods and system of pure chemical classification of cogeneration system the comparative analysis of the characteristics of the core indicators of each program. Initially that the flow structure of programs and four to yield structure is better than the solutions and other cogeneration scheme. Finally, combined with the previous research construction process of low rank coal based chemical fractions of the combined system, and further determine the furnace gas cogeneration system mainly. The analysis of the system of material transformation and energy utilization laws, including the effective atom yield, distribution of energy consumption, carbon emissions and pollutants. Hydrocarbon and transformation of furnace gas utilization scheme of grading cogeneration system The influence of the energy utilization characteristics is great, and the optimization of the furnace gas utilization subsystem should be considered in the later period.

【学位授予单位】：北京化工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TQ530

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