【作者】 王志方；

【导师】 郑丹星；

【作者基本信息】 北京化工大学 ， 化学工程， 2008， 博士

【摘要】 高效、多功能的多联产系统作为可持续发展能源利用技术,是缓解日益严重的资源、能源和环境等多方面的压力,提高能源利用率,建立资源节约型社会的重要手段。本文依托国家自然科学基金重大研究计划资助,开展天然气基乙炔化工与动力系统集成整合原则和有效途径的研究,旨在揭示氢能转化对包含氢工艺的天然气基多联产系统的作用规律,提出相应的能量集成方法,开拓新颖氢燃料热力循环系统,以及天然气基乙炔与氢能动力有机整合的多联产系统。本文主要研究内容如下:首先,研究了天然气基乙炔动力多联产系统能量集成的策略,并以逆变换反应这一关键过程研究为基础,提出了氢能间接发电的氢能利用途径。研究了逆变换反应中反应条件对氢气的转化率和吸收所需能量品位的影响规律。提出提高逆变换反应中CO₂与氢气的物质量比,不但可以降低逆变换反应热源的温度,吸收更多的低品位热,而且可以提高氢气的转化率,提高CO的生成量,从而提高系统的能量利用效率。因为在相同的条件下,CO气体比H₂气体燃烧时能够释放出更多的热量。相对于直接利用H₂的动力转化过程,这是间接转化与利用H₂的一种方法。研究认为有效转化和利用天然气基乙炔工艺副产的富氢合成气,是天然气基乙炔动力多联产系统创新的重要途径,也是核心的系统能量集成原则。提出了一种新的图式热力学分析和集成工具,及其系统能量分析与集成的启示性准则。以氢作为关键化学品,关联氢与多联产系统目的化学品的转化速率以及过程的（火用）变,提出了流量—（火用）变图FED（Flowrate Exergy Diagram）,并提出了使用FED进行含氢工艺的天然气基多联产系统能量分析与集成的一系列启示性准则。该方法直观、简明地描述复杂系统中氢或含氢化学品量改变所引起的热力学代价,便于指出能量转换的薄弱环节,提出工艺改进和系统能量集成的方法。然后,以氢能直接动力转化与间接转化两种途径,开展了下述三个天然气基乙炔动力多联产系统创新:（1）天然气基乙炔工艺与燃料电池多联产系统（氢能直接动力转化）。基于对天然气部分氧化制乙炔工艺和天然气水蒸汽重整制H₂及燃料电池PEMFC（Proton Exchange Membrane Fuel Cell）工艺的FED分析和比较,提出了一个新颖的天然气基乙炔与PEMFC多联产系统。新系统将传统合成乙炔工艺中的副产H₂作为PEMFC的H₂源,通过水气变换反应提高H₂产率,并采用催化燃烧和余热锅炉系统回收PEMFC尾气余热。研究了该多联产系统的热力学性能,并利用图式分析工具FED,研究了多联产系统的的物质和能量转化规律,揭示出天然气基乙炔与PEMFC集成的多联产系统氢能转化与能量转换利用之间的集成整合。（2）天然气基乙炔工艺与氢氧联合循环多联产系统（氢能直接动力转化）。基于对天然气水蒸汽重整制H₂及氢氧联合循环系统的分析研究,应用FED启示性准则和多联产系统集成方法,构思并设计了一种天然气基乙炔与氢氧联合循环多联产系统。研究了该多联产系统的能量转化特性和系统效率,利用FED研究了天然气基乙炔与氢氧联合循环多联产系统的氢能转化和能量集成作用。（3）天然气基乙炔工艺与逆变换化学回热循环多联产系统（氢能间接动力转化）。构思了一种由氢气CO₃逆变换化学回热、余热制冷和进气冷却构成的新型氢能间接动力转化热力循环。研究了该循环的发电效率等能量转化特性和该循环的热力学性能及其影响参数,并考察了循环压比对系统循环的影响规律,说明新循环实现了氢能的间接高效利用。进而基于对该循环的分析和天然气基乙炔动力多联产的系统能量集成原则,构思并集成了一种新型的天然气基乙炔与逆变换化学回热动力多联产系统,并研究了该多联产系统的能量转化特性和系统能量转换效率。更多还原

【Abstract】 Due to the increasing depletion of resources and energy sources all over the world, efficient and economical energy systems are of utmost importance for the future in terms of sustainable development. Polygeneration systems, which integrate high efficiency systems, are effective ways to achieve efficient resources utilizing and build an economy resource social.Supported by the NSF of China （No.: 90210032）, the major aim of this research is to investigate the integration principles and reasonable matching relations of the natural gas-based acetylene process. The major aim of this research is to propose a mechanism of hydrogen conversion and utilization in natural gas et al. fossil fuel complex energy conversion systems, and to develop a novel hydrogen power generation cycle and polygeneration systems for acetylene production and power generation. The main contents are as follows:First, the influence of operational conditions on the fractional conversion of hydrogen and the energy level needed in the conversion process of hydrgen to carbon monoxide are investigated. This paper finds out that the increasing of the molar ratio of carbon dioxide to hydrogen can achieve two aims: （1） decreasing the temperature of heat source; and （2） increasing the fractional conversion of hydrogen and increasing the content of carbon monoxide. Under the same conditions, the burning of the CO gas is able to release more heat than the H₂ gas. Comparing with the process of hydrogen conversion to power directly, H₂ and CO₂ inverse shift reaction can be considered as a indirect way of hydrogen conversion and utilization. Based on the analysis of acetylene process based on natural gas, this paper finds that when the process produces acetylene product a large amount of H₂-rich gas will be produced in the reactor. So the efficient conversion and utilization of hydrogen is an important way to establish novel polygeneration systems of acetylene and power and becomes the energy integration principles of polygeneration systems.Secondly, this paper presents a graphic analysis method will be introduced, which involves thermodynamic principles of energy analysis and energy integration, a flowrate-exergy diagram （FED）, which consists of a plot representing the increase or decrease of the flowrate of H₂ vs. the exergy change of the process, and a series of revelatory criteria to use the FED mainly from process configuration. In some complex energy conversion process system related to hydrogen, as like as an acetylene production process, the influence of hydrogen conversion and utilization on the characteristics of energy conversion is very important. The proposed tool visually and concisely describes the conversion rates of hydrogen and hydrogenous chemicals associating with the exergy loss. Based on the analysis and comparison of the graph it is able to discover the cause of affecting the hydrogen conversion efficiency and find out the relative advanced technology. Then the FED may be used to develop retrofitting processes to improve the energy conversion efficiency.Then three novel acetylene production and power generation polygeneration systems based on natural gas systems were developed and investigated in this paper. They related to direct power conversion and indirect conversion of hydrogen.Based on the investigation of partial oxidation/combustion （POC） of natural gas for producing acetylene process and the proton exchange membrane fuel cell （PEMFC）, a novel polygeneration system that integrates the acetylene process and fuel cells is presented. The system produces acetylene and power by a process of the POC of natural gas process, a water gas water-gas shift reactor, a fuel cell and a waste heat boiler auxiliary system to recover the exhaust heat and gas from the fuel cell. The new polygeneration system’s exergy analysis and the flow rate of the products were investigated by the aid of FED, to reveal that the energy conversion and systematic integration mechanism demonstrated the improvement of natural gas energy conversion efficiency.Based on the analysis of steam reforming of natural gas and H₂/O₂ cycle system, a novel acetylene and H₂/O₂ cycle polygeneration system was proposed by the use of FED revelatory criteria and system integration method. The energy conversion characteristics and system efficiency of the system are researched. The thermodynamic principle of the new system and coupling mechanism for hydrogen conversion and energy integration between the acetylene process based on natural gas and H₂/O₂ cycle were both revealed with the aid of FED method.A novel high-efficiency power cycle system is proposed, which is composed of chemical recuperative with H₂ and CO₂ reverse shift reaction, chemical heat recovery with an ammonia absorption refrigeration cycle, and cooling the inlet gas. First, the heat is recovered from the turbine exhaust to drive H₂ and CO₂ reverse shift reaction, and then lower temperature heat from the turbine exhaust is provided with the ammonia absorption refrigeration system to generate chilled media, which is used to cool the turbine inlet gas except export. In this paper, a detailed thermodynamic analysis is carried out to reveal the performance of the proposed cycle and the influence of key parameters pressure ratio and temperature of interlet on performance is discussed, which shows the new cycle achieves the indirect efficient use of hydrogen. Based on the analysis of the power cycle and the energy integration principles of acetylene and power polygeneration systems, a new acetylene and power polygeneration system is proposed.更多还原