高固气比下粉体预热器系统的热效率研究

进行了粉体在高固气比下的多系列热效率的理论研究，指出双系列热热器系统是较为理想的高固气比预热器系统。针对预热器级数、漏风系数对双系列热效率的影响展开研究，其规律对新型预热器系统的开发具有指导意义。     

活性石灰生产线中回转窑预热器顶部的改造

新型、高效、低压损的活性石灰生产线系统包括竖式预热器、回转窑和冷却器。竖式预热器是其中的重要部分，而预热器顶部采用不同的形式对生产又起到了至关重要的作用。本文通过对预热器顶部的改造实例来说明采用整体吊挂砖形式可以大大延长预热器顶部的使用寿命，保证生产过程的安全顺利进行。     

HTT energy systems GmbH热传导技术的专家

HTT可覆盖整个加热、冷却液、温度控制工艺领域。化工用热油加热炉是HTT专为化学化工工业制造。采用立式单程设计．配有空气预热器和烟气回流装置，可保证达到最高热效率和最低排放标准。     

内可逆闭式中冷回热布雷顿循环效率优化

以热效率为目标，应用有限时间热力学的方法优化了恒温热源务件下内可逆闭式中冷回热布雷顿循环的中间压比分配和高低温侧换热器、中冷器及回热器热导率分配．得到循环最大热效率．进一步对总压比优化，可以得到双重最大效率．通过数值计算，研究了一些重要参数对循环优化结果的影响．     

全封闭式涡旋膨胀机在车用有机朗肯循环中的特性研究

本文针对中低温余热特性搭建了2kW目标发电量的小型有机朗肯循环发电系统。实验研究了全封闭式涡旋膨胀机在有机朗肯循环系统中的参数特性。通过改变膨胀机进出口的状态,研究了运行压比和转速对于膨胀机单体及系统性能的影响。性能参数主要包括等熵效率、容积系数、循环热效率及循环净功。结果表明:膨胀机运行压比是影响系统性能的重要参数,循环净功随压比的增大而增加,循环热效率及膨胀机的等熵效率随压比变化均存在最优值;考虑内泄漏及摩擦损失等影响,最优运行压比一般应略大于膨胀机设计比;提高膨胀机转速能有效减少内泄漏损失。     

空气预热器漏风率对锅炉热效率的影响及分析

回转式空气预热器作为重要的尾部换热设备被广泛的应用在电站锅炉上,漏风率较高作为该设备使用过程中不可避免的缺点影响了整个机组运行的经济性、可靠性及安全性,是电站提高运行经济效率及运行安全需要解决的问题。本文通过对电站锅炉进行现场试验,分析了该电站空气预热器的漏风情况,同时分析了漏风率对锅炉热效率的影响,对评价电站的运行经济性具有一定的指导意义。     

简述空气预热器的腐蚀原因

空气预热器在锅炉系统中是一个非常重要的设备,在使用的过程中作用非常明显,但是在近些年的空气预热器的系统常规检查中,发现了腐蚀现象,这样会影响到空气预热器的使用。因此本文针对空气预热器的腐蚀原因及相关的处理腐蚀的方法进行阐述和分析,希望通过本文的分析和阐述可以对我国的空气预热器的腐蚀现象的处理有所帮助。     

燃煤锅炉的空气预热器积灰在线监测

本文以安庆皖江电厂2#锅炉为对象，利用现有的DCS系统中的数据，建立空气预热器的在线监测模型。经现场实践得以验证模型的可行性，能够实现空气预热器积灰的在线监测。     

某钢厂4#发电机组燃气锅炉空气预热系统优化研究

某钢厂4#发电机组燃气锅炉排烟温度过低,导致所排烟气结露,含硫液体析出,造成锅炉空气预热器及钢烟道严重腐蚀。本项目通过对锅炉空气预热系统进行优化研究,以提高进入空气预热器的空气温度,防止锅炉烟气低温腐蚀。     

焦化加热炉空气预热器振动及减振

焦化装置组合式空气预热器试运行时产生强烈振动，对组合式空气预热器产生振动的原因进行分析，卡门涡流是预热器产生振动的主要原因。提出合理的消振方案，通过改造，该预热器消除了振动，恢复了正常的运行。     

电厂锅炉优化改造试验分析

为进一步提高锅炉效率,减少锅炉污染物排放,以某电厂锅炉为研究对象,对锅炉的空预器密封装置、水平烟道吹灰系统以及高压省煤器进行等进行整体优化,对锅炉进行化学清洗和保温处理,通过试验对优化前后对锅炉热效率及污染物排放进行对比。结果表明：与改造前相比,不同负荷下锅炉效率平均提高2.3%,同时供电煤耗降低;锅炉排烟温度降低,干烟气热损失减少;未燃尽率碳热损失及空预器漏风率也大幅降低,锅炉排放NOx浓度达到排放要求。此次优化改造达到了预期效果。     

高温高固气质量比条件下旋风预热器换热管压降的研究

为了掌握旋风预热器换热管压降随温度、风速和固气质量比的变化规律,在各种不同条件下,对旋风预热器换热管压降进行测试。结果表明:在气流速度固定不变的情况下,当固气质量比z≤1时,随着温度的升高,压降先增大后减小,在200℃附近出现高点;当固气质量比z≥1.5时,随着温度的升高,压降逐渐减小,在600℃附近趋于平缓,之后随着温度的升高略有增大。压降总是随着风速的提高而增大,随着固气质量比的增加而增大。     

SIMULATION OF GAS FLOW IN BLAST FURNACE FOR DIFFERENT BURDEN DISTRIBUTION AND COHESIVE ZONE SHAPE

Blast furnace is a very complex physico-chemical process with countercurrent flow of gas and solid. Computation of gas flow through different regions of blast furnace can be considered as the first major step towards numerical simulation of the process. Gas velocity profile in blast furnace depends on the burden distribution and shape of the cohesive zone, which affect the overall thermal efficiency and utilization of reduction potential of the gas (CO/CO₂ratio). Nonuniform or high gas flow near the wall causes overheating of the wall, which leads to high rate of refractory erosion and heat loss. High gas flow through the central region, on the other hand, causes higher CO/CO₂ratio at the center, leading to reduction in chemical and thermal efficiency of the gas. Therefore, achieving an optimum gas flow by controlling the burden distribution and shape of the cohesive zone is very important for minimizing refractory loss, thermal and chemical efficiency of the process. Gas velocity through various zones of blast furnace is computed by solving vectorial Ergun's equation for flow through porous medium considering axi-symmetric condition. To incorporate the shape of blast furnace efficiently, one-dimensional stretching in radial direction or nonorthogonal body-fitted coordinate system is used by the standard (x,y)to (ξ,η)transformation method. This model can be used for optimizing burden distribution and developing gas velocity control systems for blast furnace.     

空预器风阻对锅炉的影响分析

对于华电包头锅炉的空气预热器（容克式）,在运行中由于积灰造成预热器的堵塞,对锅炉的效率、预热器的磨损及吸风机、送风机的电耗增大等问题,本文主要介绍华电包头空气预热器水冲洗后锅炉排烟温度及吸风机、送风机电耗的影响。     

Exergy analysis of gas turbine trigeneration system for combined production of power heat and refrigeration

A conceptual trigeneration system is proposed based on the conventional gas turbine cycle for the high temperature heat addition while adopting the heat recovery steam generator for process heat and vapor absorption refrigeration for the cold production. Combined first and second law approach is applied and computational analysis is performed to investigate the effects of overall pressure ratio, turbine inlet temperature, pressure drop in combustor and heat recovery steam generator, and evaporator temperature on the exergy destruction in each component, first law efficiency, electrical to thermal energy ratio, and second law efficiency of the system. Thermodynamic analysis indicates that exergy destruction in combustion chamber and HRSG is significantly affected by the pressure ratio and turbine inlet temperature, and not at all affected by pressure drop and evaporator temperature. The process heat pressure and evaporator temperature causes significant exergy destruction in various components of vapor absorption refrigeration cycle and HRSG. It also indicates that maximum exergy is destroyed during the combustion and steam generation process; which represents over 80% of the total exergy destruction in the overall system. The first law efficiency, electrical to thermal energy ratio and second law efficiency of the trigeneration, cogeneration, and gas turbine cycle significantly varies with the change in overall pressure ratio and turbine inlet temperature, but the change in pressure drop, process heat pressure, and evaporator temperature shows small variations in these parameters. Decision makers should find the methodology contained in this paper useful in the comparison and selection of advanced heat recovery systems.     

A technique for the determination of 18O/16O and 17O/16O isotopic ratios in water from small liquid and solid samples

We have developed a new technique in which a solid reagent, cobalt(III) fluoride, is used to prepare oxygen gas for isotope ratio measurement from water derived either from direct injection or from the pyrolysis of solid samples. The technique uses continuous flow, isotope ratio monitoring, gas chromatography/mass spectrometry (irmGC/MS) to measure the delta18O and delta17O of the oxygen gas. Water from appropriate samples is evolved by a procedure of stepped pyrolysis (0-1000 degrees C, typically in 50 degrees C increments) under a flowing stream of helium carrier gas. The method has considerable advantages over others used for water analysis in that it is quick; requires only small samples, typically 1-50 mg of whole rock samples (corresponding to approximately 0.2 micromol of H2O); and the reagent is easy and safe to handle. Reproducibility in isotope ratio measurement obtained from pyrolysis of samples of a terrestrial solid standard are delta18O +/- 0.54, delta17O +/- 0.33, and delta17O +/- 0.10/1000, 1sigma in all cases. The technique was developed primarily for the analysis of meteorites, and the efficiency of the method is illustrated herein by results from water standards, solid reference materials, and a sample of the Murchison CM2 meteorite.     

空气预热器蓄热元件腐蚀原因分析

通过宏观检验、化学成分分析、金相检验、硬度测试、扫描电镜分析、能谱分析以及X射线衍射分析等方法,对某厂600 MW亚临界锅炉空气预热器冷端蓄热元件的腐蚀原因进行了分析。结果表明:该蓄热元件的腐蚀为烟气中SO₂/SO₃气体作用下发生的低温腐蚀。并针对蓄热元件的腐蚀原因提出了预防措施。     

Thermodynamic performance analysis of three solid oxide fuel cell and gas microturbine hybrid systems for application in auxiliary power units

In this study, three different configurations of a solid oxide fuel cell and gas microturbine hybrid system are evaluated for application in auxiliary power units. The first configuration is a common hybrid system in auxiliary power units, utilizing a fuel cell stack in the structure of the gas turbine cycle. The other configurations use two series and parallel fuel cell stacks in the structure of the gas turbine cycle. The main purpose of this research is thermodynamic analysis, evaluation of the performance of the proposed hybrid systems in similar conditions, and selection of an appropriate system in terms of efficiency, power generation, and entropy generation rate. In this study, the utilized fuel cells were subjected to electrochemical, thermodynamic, and thermal analyses and their working temperatures were calculated under various working conditions. Results indicate that the hybrid system with two series stacks had maximum power generation and efficiency compared with the other two cases. Moreover, the simple hybrid system and the system with two parallel stacks had relatively equal pure power generation and efficiency. According to the investigations, hybrid system with two series fuel cell stacks, which had 3424 and 1712 cells, respectively, can achieve the electrical efficiency of over 48%. A hybrid system with two parallel fuel cell stacks, in which each stack had 2568 cells, had the electrical efficiency of 46.3%. Findings suggested that maximum electrical efficiency occurred between the pressure ratios of 5–6 in the proposed hybrid systems.     

A monolithic CMOS microhotplate-based gas sensor system

A monolithic CMOS microhotplate-based conductance-type gas sensor system is described. A bulk micromachining technique is used to create suspended microhotplate structures that serve as sensing film platforms. The thermal properties of the microhotplates include a 1-ms thermal time constant and a 10/spl deg/C/mW thermal efficiency. The polysilicon used for the microhotplate heater exhibits a temperature coefficient of resistance of 1.067/spl times/10/sup -3///spl deg/C. Tin(IV) oxide and titanium(IV) oxide (SnO/sub 2/,TiO/sub 2/) sensing films are grown over postpatterned gold sensing electrodes on the microhotplate using low-pressure chemical vapor deposition (LPCVD). An array of microhotplate gas sensors with different sensing film properties is fabricated by using a different temperature for each microhotplate during the LPCVD film growth process. Interface circuits are designed and implemented monolithically with the array of microhotplate gas sensors. Bipolar transistors are found to be a good choice for the heater drivers, and MOSFET switches are suitable for addressing the sensing films. An on-chip operational amplifier improves the signal-to-noise ratio and produces a robust output signal. Isothermal responses demonstrate the ability of the sensors to detect different gas molecules over a wide range of concentrations including detection below 100 nanomoles/mole.     

Continuous “Snowing” Thermotherapeutic Graphene

Finding the best applications of graphene, and the continuous and scalable preparation of graphene with high quality and high purity, are still two major challenges. Herein, a “pulse-etched” microwave-induced “snowing” (PEMIS) process is developed for continuous and scalable preparation of high-quality and high-purity graphene directly in the gas phase, which is found to have excellent thermotherapeutic effects. The obtained graphene exhibits small size (≈180 nm), high quality, low oxygen content, and high purity, together with a high gas–solid conversion efficiency of ≈10.46%. Considering the intrinsic characteristics of this high-purity and small-sized biocompatible graphene, in particular the low-frequency microwave absorption property as well as the good thermal transformation ability, a graphene-based combination therapeutic system is demonstrated for microwave thermal therapy (MTT) for the first time, exhibiting a high tumor ablation rate of ≈86.7%. This is different from the principle of ions vibrating in a confined space used by current MTT sensitization materials. Not limited to this application, it is foreseen that this PEMIS-based high-quality graphene will allow the search for further suitable applications of graphene.