有效能分析法讲座(三)——第三讲 有效能衡算

在对一个系统或过程作出物料衡算和能量衡算,并且根据各股物流及能流的热力学性质,求出它们的单位质量(或能量)的有效能之后,可以进行该系统或过程的有效能衡算,从而确定参与系统或过程的各股物流和能流的有效能,以及系统或过程中产生的有效能损失。同时,若将结果用有效能能流图表示出来,则可以直观形象地揭示出系统或过程中有效能转化     

合成氨装置的有用能分析

近年来对各种动力工业过程的研究广泛采用热力学分析的有用能方法。它与通常的能量分析不同,不仅考虑到产生的与消耗的能流和物流的量,而且研究其性质。除此之外,有用能的分     

大型合成氨装置蒸汽动力系统的有效能分析

简述热力学的有效能分析法,运用该法分析计算了大型合成氨装置蒸汽动力系统各个部分及各主要蒸汽透平的有效能效率,给出了Kellogg和TEC装置中这个系统的有效能能流图,并对比了它们的热力学完善程度。     

过程能量综合技术在味精生产企业能量优化中的应用（Ⅱ）——味精生产过程“三环节”能量系统改进措施

以某味精生产企业能量系统为研究背景,提出了该企业能量系统改进的方向;并以"三环节"模型为研究思路,根据该企业的工艺流程和设备运行状况,提出了一系列能量系统改进措施,通过热力学分析,这些改进措施预计可使该企业的净能耗减少18.59%,热量回收率提高20.34%,火用回收率提高10.37%,表明本研究提出的能量改进方案是可行的,模型是可靠的。     

生态工业园的能量集成探讨——余热利用技术

基于生态工业园能量集成理论和热力学原理,阐述了生态工业园物流与能流的共生耦合资源化余热利用模式。在分析硫酸生产和黄磷尾气余热利用潜力的基础上,指出了在余热利用模式引导下的资源化途径。生态工业园余热回收利用使能源在产业链中得到充分利用,可提高园区能源效率并减少污染物的排放,是实现生态工业园能量集成的重要途径。     

粒子能级序列图用于解析统计热力学教学难点

粒子配分函数,是统计热力学研究的核心。本科物理化学教学中,学生常常由于对粒子不同运动形式的能量序列缺乏理解,而对诸多统计热力学基础问题产生疑惑。本文建议将粒子能级序列图引入教材和教学。该能级序列图便于学生准确理解该统计热力学教学的核心内容和难点内容,能有效地提高教学效果。     

陶瓷生态工业园的陶瓷生产过程能量集成分析

基于生态工业园能量集成理论和热力学原理,阐述了陶瓷生态工业园物流与能流的共生耦合资源化余热利用模式。在分析陶瓷生产过程和窑炉尾气余热利用潜力的基础上,指出了在余热利用模式引导下的资源化途径。陶瓷生态工业园余热回收利用使能源在产业链中得到充分利用,可提高园区能源效率并减少污染物的排放,是实现生态工业园能量集成的重要途径。     

企业、产品能流图的编制及其功能

能流图是进行能源科学管理,探讨企业节能方向和途径的主要依据。正确的运用能流图是实现科学用能,提高能源利用率,降低能耗的一项重要的基础工作。 企业能流图是以企业为对象,用图形表示出企业的能量输入,能量转换、能量损失以及能量输出等项之间的平衡关系。     

复杂化工过程系统的能值计算方法

针对复杂过程系统的生态化设计,研究系统内部及输出流股能值的计算策略和方法。基于系统能量或质量流程图,确定系统内外的能流、物流的分布和能量分配系数,通过建立复杂系统能值计算的循迹法,确定系统各种输入能值在系统内的分配,解决复杂系统内部联结各单元的流股能值准确计算问题。基于该方法,对玉米燃料乙醇生产过程系统进行了能值分析和评价。     

改善滑石瓷注浆泥工艺性能的新方法

介绍了一种制备滑石瓷注浆泥的新方法。用该方法制备的注浆泥流动性好，不稠化，含水率低，便于生产。并对新方法进行了理论分析，给出了检验注浆泥性能的四个指标。     

多产品工业系统的能值分析

介绍了起源于生态领域的能值分析方法. 为了扩展能值分析方法的应用范围,根据能值分析的基本思想,并以能量守恒和能值守恒为依据,建立了多产品工业系统能值分析模型. 将能量分率作为分配系数,提出了评价多产品工业系统的评价指标：共生指数. 为了获得对比结果,还对相应的单产物系统提出了数均指数. 若共生指数优于数均指数,则多产品联产系统优于单产系统. 通过垃圾焚烧热电联产方案的能值分析,验证了多产品的能值分析模型. 并与常规燃煤热电联产系统进行了比较,以说明能值分析方法的优势.     

Performance improvement of integrated coal gasification combined cycle by a new approach in exergy analysis

A new approach to exergy analysis is proposed for examing the consumption of energy as the minimum driving force and of exergy consumption that is avoidable, and for the development of a method to predict the alternatives in system improvement by exploring possible reduction in the avoidable exergy consumption. Also suggested in this study is a dimensionless parameter γ_AVO, which is the ratio of avoidable exergy consumption over total fuel energy input to the system. Detailed analyses, including the calculation of exergy consumption, exergy loss and avoidable exergy consumption, were conducted for each component in the syngas cooling system in the Integrated coal Gasification Combined Cycle (IGCC) plant, to prove the effective application of the proposed method. The analysis showed that the rank of avoidable exergy consumption was different from that of total energy consumption, and hence it confirmed that an energy analysis by conventional methods misled the focus of improvement in system design. The methodology developed in this study offers a new approach for system designers to analyze and to improve the performance of a complex energy system such as an IGCC plant.     

Energy savings bottleneck diagnosis of cooling system based on integrated correlation analysis

The circulation cooling system is an important auxiliary system in industry and has great potential for saving energy. However, a holistic energy savings retrofit of the system can cause high costs and a low input–output ratio. To address this problem, this paper integrates grey correlation analysis and partial correlation analysis to propose a new energy savings bottleneck diagnosis method for the circulating cooling system. This method deeply analyzes the operation mechanism of the industrial circulating cooling system and summarizes the main energy-savings factor. Through the energy savings bottleneck diagnosis method based on grey correlation analysis and partial correlation analysis, the energy savings correlation coefficient and energy savings difference coefficient are calculated, and the relationship between each energy savings factor and the specific energy consumption is accurately described and quantified. Furthermore, the system energy savings bottleneck diagnosis is performed and the quantified energy savings priority of each system link is obtained. It can effectively guide the implementation of system energy savings optimization and retrofit. Finally, the effectiveness of the diagnosis method is demonstrated by simulation verification with actual network data.     

能量利用系统的能量流结构——能量、[火用]、[火无]赋新概念

认为[火用]是系统和环境构成的不平衡复合系统作功能力的衡量，重新表述了[火用]概念，论证了[火用]不是严格意义上系统的状态参数。指出环境能量在任何情况下都不能用于作功的传统观点是违背热力学第二定律的，能量利用的实质是利用系统和环境之间非平衡推动力引发的动态能量流，它包含可转化能量的多少与能量流的方向无关，无论来自系统还是环境的能量都可被转化。文中给出的能量、[火用]、[火无]新概念严格遵守热力学第二定律，克服了Rant Z．定义的局限性，对进一步改进[火用]分析方法促进用能过程热力学的发展有积极意义。     

能量利用系统的能量流结构——能量、、(火无)新概念

认为火用是系统和环境构成的不平衡复合系统作功能力的衡量,重新表述了火用概念,论证了火用不是严格意义上系统的状态参数。指出环境能量在任何情况下都不能用于作功的传统观点是违背热力学第二定律的,能量利用的实质是利用系统和环境之间非平衡推动力引发的动态能量流,它包含可转化能量的多少与能量流的方向无关,无论来自系统还是环境的能量都可被转化。文中给出的能量、火用、火无新概念严格遵守热力学第二定律,克服了Rant Z.定义的局限性,对进一步改进火用分析方法促进用能过程热力学的发展有积极意义。     

Reduction of Empiricism through Flow Visualization and Computational Fluid Dynamics

In chemical process industry, a variety of equipment is used for carrying out different unit operations and unit processes. The design procedures for this equipment have been largely empirical due to the complexity of fluid mechanics. In view of this, a stepwise procedure has been suggested based on experimental fluid dynamics (EFD) and computational fluid dynamics (CFD). One application of EFD and CFD is presented for the prediction of the heat transfer coefficient in the single‐phase turbulent pipe flow. The present capabilities of CFD for the design of different process equipment have been outlined.     

提高等离子体裂解煤制乙炔收率的方案研究

将反应体系的温度升高到升华点以上 ,是提高等离子体裂解煤制乙炔收率的必由之路 .采用最小自由能方法研究了煤的 C- H- O热力学平衡体系 ,在此基础上提出了一种以煤层气甲烷为冷却剂的等离子体裂解煤制乙炔方案 ,初始反应体系的温度在 40 0 0 K以上 .理论的计算和分析结果表明 ,这种方案可获得较高的乙炔收率 ,而单位质量乙炔的比能耗很低 ,具有很好的经济效益和环境效益 .     

声波测量在搅拌釜中固体颗粒临界悬浮转速测定的应用

基于声发射测量技术,结合声信号的频谱分析、小波分解和R/S分析,获得了代表颗粒运动的特征信号频段（d₁、d₂频段）。同时,根据声波特征信号频段能量随搅拌转速的规律性变化,以固体颗粒碰撞壁面产生信号高频区域的声能量分率值为特征参数,提出了搅拌釜临界悬浮转速的测量判据,即声能量分率快速减少并开始趋于稳定时所对应的搅拌转速为临界悬浮转速。以水-玻璃珠体系为例,与目测法相比,声波法测量值的平均相对误差为3.51%,具有较高的精度。利用经典的Zweitering临界悬浮转速计算公式对声波法测得的实验数据进行拟合,计算值与测量值之间的平均相对误差为3.17%,表明公式对于临界悬浮转速的计算具有较高的准确性。由此获得了一种快速、准确、安全的搅拌釜反应器临界悬浮转速测量技术,有利于工业生产流程的优化和控制。     

Graphic exergy analysis of chemical process systems by a graphic simulator, Gschemer

A graphic tool for process system analysis and/or synthesis based on the second law of thermodynamic is developed. When a simple program to describe the system is given, the compiler GSCHEMER, Graphic Structured CHEMo-synthesizER, will analyze it and display the energy utilization diagrams, clarifying the extent of exergy loss in each part of the system. This method covers operations of chemical reaction, heat exchange and gas compression and expansion. In addition, these diagrams may reveal the causes of exergy loss in each subsystem and give some hint as to how it may be reduced. This systematic visual procedure may be applied not only for process system analysis and evaluation but also for synthesis of new systems to save energy.

In this paper, a sample program for coal gasification is given.

Scope—To efforts to get efficient energy transformation in chemical or energy process systems may be classified into two stages: analysis (or evaluation) and synthesis. In previous methods for energy analysis, the object processes were often treated as black boxes and only the energy efficiency in them was evaluated by the thermodynamic properties of the flows at their inlets and outlets. Such methods have been applied for a long time but they are generally insufficient to obtain information on how the system may be improved.

With respect to the synthesis of process system networks or the optimization of the system structure and operation variables, many mathematical methods have been proposed. Among them, graphic methods for heat-exchange networks such as the heat-content diagram by Nishida et al. [1], the heat-temperature diagram by Hohman [2], the heat-available energy diagram by Umeda et al.. [3] and their applications [4] are the most successful, because graphic methods are best-suited to inspire human intuition. However, most of them are not beyond the scope of heat-exchange operations.

Hence graphic methods which may be applied to any kind of process system may become candidates for the method of energy analysis and system synthesis in the next generation.

In a previous paper [5], one of the authors has proposed the energy-direction factor diagram. Although it has characteristics similar to Umeda et al.'s diagram [3] for heat-exchange operations, in the sense that the exergy loss in the network can be represented as the area between the heat-donating line and the heat-accepting one, it has much wider applications-including chemical reaction, gas compression and work generation.

In another paper, Ishida has proposed a compiler-type steady-state process system simulator SCHEMER, Structured CHEMo-synthesizER [6], in which the introduction of the concept of “stream stack” makes the simulator quite compact.

The purpose of this study is to combine the advantages of these two efforts and develop a new graphic simulator GSCHEMER. It will display energy-utilization diagrams which may become a powerful tool in energy analysis and process system synthesis.

Conclusions and Significance—(1) A graphic simulator, GSCHEMER, for steady-state process systems is developed.

(2) Energy-utilization diagrams, which are an extended version of the energy-direction factor diagrams, are automatically generated for each subsystem such as heat-exchange operation, work task and chemical reaction.

(3) Each diagram shows the energy balance, the extent of exergy loss and the extent of the approach to equilibrium, especially at the pinch point in each subsystem, which are of great importance in finding the causes of irreversibilities and in proposing a new system structure.     

变温吸附碳捕集系统能效性能对标分析

准确且合理的能耗分析对碳捕集技术规模化发展至关重要,其既是碳捕集技术节能降耗的必要前期准备,也是碳捕集过程开展绿色化、清洁化性能评价的重要数据基础。因此,在对碳捕集过程的能源转换共性展开探索的同时,迫切需要面向工程实践的需求,形成易于操作的能效性能对标分析方法,从而保证对类型技术的性能认知可以在合理且统一的评价平台上进行归纳与比较。本工作基于对标分析(Benchmarking Analysis)方法,对变温吸附碳捕集(TSA)过程的能耗分析方法进行了阐述,包括流程、参数、模型等。研究了吸附温度和解吸温度对TSA能效性能结果的影响,演示并量化了该方法的可行性,重点对边界变化对评价结果的影响进行了讨论。提出的对标分析方法对碳捕集技术的能效性能对标评估给出了较具体的指导。