黄龙滩水电站水库优化调度研究

本文以三种径流随机描述方案为基础,研究了运用于三种径流随机过程有面临时段径流预报的水库随机优化的通用数学模型。通过黄龙滩水库的模拟运行验证了优化调度方案的有效性。对不同径流随机描述方案的运行成果的对比分析,揭示了不同的径流随机描述对优化调度影响的趋势。     

抽水蓄能SFC拖动过程电能质量测试方案设计及应用

抽水蓄能电站SFC拖动过程易引发电能质量问题,并由此导致用电设备损坏和寿命大幅小于预期等,因此研究和制定全面系统的SFC拖动过程电能质量测试方案。结合SFC的结构和拖动过程特点等场景,描述了SFC拖动过程全站电能质量测试方案的测试范围和主要内容,并介绍了方案的应用结果,对抽水蓄能电站电能质量的系统性测量进行了有益的尝试。     

雷州新型煤粉燃烧器制造攻关

本文重点描述雷州工程自主研发的新型角式煤粉燃烧器试制过程中遇到的问题和改进方案,以此为基础完善了装配工艺,并提高了工作效率,保证了产品质量。     

气化炉洗涤冷却环试制及优化

本文主要描述了世界日投煤量最大的气化炉中的核心部件洗涤冷却环,在试制过程中采取的一系列制造优化方案,保证了冷却环高精度的要求,最终试制成功,并连续生产制造,积累了宝贵的制造经验。     

乌沙山新型旋流煤粉燃烧器试制及优化

本文重点描述乌沙山新型旋流煤粉燃烧器试制过程中遇到的问题和改进方案,以此为基础优化了新型旋流煤粉燃烧器的设计结构,使得新产品能较好的保证应有的低氮排放功能。     

锅炉故障诊断专家系统的知识表达

针对循环流化床锅炉实际应用对象的特性，采用面向对象的方法对其进行了分析与描述，提出了现阶段可以实际应用于锅炉系统的故障诊断专家系统的知识处理方案，详细叙述了框架、规则、过程的知识表达方法。     

如何实现210双燃料发动机自动控制

主要介绍了210型双燃料发动机的总体设计方案,重点描述了该型双燃料发动机的天然气控制系统,以及如何在试验过程中实现自动控制。试验结果表明:210型双燃料发动机实现了自动控制,双燃料模式下最高燃油替代率为80%,从而获得了较好的经济性能,其它性能指标也均达到设计要求。     

某600MW汽轮机中压主汽门卡涩原因分析与处理

描述了某600MW机组中压主汽门的卡涩现象,对各种原因进行了分析,并采取了切实有效的处理方案。     

风电场功率控制策略研究与应用

文章根据国家电网对风电场功率控制的需求,提出了风电场功率控制方案。主要描述了风电场功率预测方法、降功率策略以及浅限幅、深限幅的具体策略。该方案经过现场实测,各项指标均达到国家电网要求。     

9FA燃气轮机试车站进气系统密封几点问题

介绍了9FA燃气轮机试车站进气系统的原理、构成以及该设备在制造、安装中出现的几点问题和解决这些问题工艺措施及检验方法,对采用的方案进行了简要的描述,为类似工程项目提供了可行的方案参考。     

电站煤粉炉生物质混燃技术及关键设备分析

生物质混燃发电技术是环境友好、高效经济的规模化利用技术,应用前景广阔.总结了现有生物质混燃技术和国内外应用现状,介绍了一种生物质能高效利用的新方式,即在煤粉炉中使用独立喷燃技术燃用生物质成型燃料的方案,该方案将成为未来发展方向.分析了生物质在大容量煤粉炉中混燃发电技术的可行性,讨论了该混燃技术的关键设备选型配置情况和系统要求,指出了该混燃技术要实现规模化推广存在的主要矛盾,并提出了相应的建议.     

Influence of functional group structures on combustion behavior of pulverized coal particles

The ignition and combustion behavior of pulverized coal was studied with respect to coal rank in a custom-designed visual drop tube furnace. The results showed that low-rank coals were ignited in a shorter time, mainly due to the presence of larger amounts of functional groups, while the ignition delay time of high-rank coals was longer. With increasing temperature and particle size, the ignition mode of coals shifted from heterogeneous into homogeneous, which was related to the increased yield of volatile matter. The chemical percolation devolatilization analysis results showed a clear relationship between the yield and composition of volatile matter and the amount and type of functional groups in coal. In addition, the tar yield was consistent with the amount of aliphatic hydrocarbons and the length of aliphatic chains, which explained the tailing combustion mode of the bituminous coal. The findings of the study showed that the yield and composition of volatiles in coal had a significant impact on the ignition behavior, which depended on the composition of functional groups, particle size, and the combustion environment.     

Power generation from pulverized coal in China

The growth of power generation in China since the 1980s has been reviewed by analyzing the relationship between demand and supply of power, the increasing in installed capacity, and the variations in power-resource structure. Currently, the power generation from pulverized coal (PC) is dominant in the China's power industry, with relevant PC-power-generation technologies being introduced in the past two decades; such technologies were introduced to tackle various issues such as economy, reliability, and pollutant emissions. Furthermore, some of the problems related to PC-power generation in China have been discussed herein. Accordingly, the prospects of PC-power generation in China are predicted, considering the aspects of emission reduction and improvements in efficiency and reliability.     

On the burning behavior of pulverized coal chars

A model that predicts the physical changes that pulverized coal char particles undergo during combustion has been developed. In the model, a burning particle is divided into a number of concentric annular volume elements. The mass loss rate, specific surface area, and apparent density in each volume element depend upon the local particle conditions, which vary as a consequence of the adsorbed oxygen and gas-phase oxygen concentration gradients inside the particle. The model predicts the particle's burning rate, temperature, diameter, apparent density, and specific surface area as combustion proceeds, given ambient conditions and initial char properties. A six-step heterogeneous reaction mechanism is used to describe carbon reactivity to oxygen. A distributed activation energy approach is used to account for the variation in desorption energies of adsorbed O-atoms on the carbonaceous surface. Model calculations support the three burning zones established for the oxidation of pulverized coal chars. The model indicates two types of zone II behavior, however. Under weak zone II burning conditions, constant-diameter burning occurs up to 30% to 50% conversion before burning commences with reductions in both size and apparent density. Under strong zone II conditions, particles burn with reductions in both size and apparent density after an initial short period (<2% conversion) of constant-diameter burning. Model predictions reveal that early in the oxidation process, there is mass loss at constant diameter under all zone II burning conditions. Such weak and strong burning behavior cannot be predicted with the commonly used power-law model for the mode of burning employing a single value for the burning mode parameter. Model calculations also reveal how specific surface area evolves when oxidation occurs in the zone II burning regime. Based on the calculated results, a surface area submodel that accounts for the effects of pore growth and coalescence during combustion under zone I conditions was modified to permit the characterization of the variations in specific surface area that occur during char conversion under zones II conditions. The modified surface area model is applicable to all burning regimes. Calculations also indicate that the particle's effectiveness factor varies during conversion under zone II burning conditions. With the adsorption/desorption mechanism employed, a near first-order Thiele modulus-effectiveness factor relationship is obeyed over the particle's lifetime.     

Distribution of mineral matter in pulverized coal

Mineral transformations, and therefore fly ash evolution, during pulverized coal combustion, depend on the amount, composition and spatial distribution of the inorganic matter within individual pulverized coal particles. Thus, it is necessary to have information on the mineral composition of individual particles, as well as that of the raw pulverized coal. A model is proposed based on the assumption that mineral inclusions of size and composition determined using a CCSEM are distributed randomly in the coal. From this distribution it is possible to generate distributions of mineral content for any particle size and density fraction of coal. The model has been checked by comparing computed results with data on the compositional variations of narrowly and density classified fractions of an Upper Freeport bituminous coal. The results of individual coal particle compositions are used to generate information on the variability of the composition of the fly ash generated during combustion.     

Experimental study on gasification mechanism of unburned pulverized coal catalyzed by alkali metal vapor

The catalytic behavior of alkali vapor on unburned pulverized coal (UPC) prepared from bituminous coal, anthracite, semi coke and coke have been investigated. Experiment results show that the alkali metal vapor has catalytic effect on the gasification reaction of UPC. The catalytic effect of coke UPC is the most obvious, followed by anthracite UPC and bituminous coal UPC. Semi coke UPC is the least catalyzed by alkali metals but its gasification reactivity is the best. As the concentration of alkali metal vapor increases, the alkali metal content adsorbed by UPC increases, and there may be a phenomenon of saturated adsorption. The amount of alkali metal adsorbed is between 2% and 6%. AUPC has the highest ability to adsorb alkali metals, and SUPC is the weakest, which may be related to the minerals (CaO, Al₂O₃) in the coal ash. Changes in stomatal parameters are not the main factors affecting the catalytic effect. The results of X-ray diffraction experiments show that alkali metal aluminosilicate exists in the ash of coal after adsorption of alkali metal, and the average stack height of carbon atoms decreases significantly. The alkali metal catalytic gasification reaction is mainly achieved by destroying the carbon basic structural unit. The alkali metal nepheline and the interlayer compound may be the main catalytic substances, and the destructive ability of alkali intercalation is obviously stronger than that of alkali nepheline. The catalytic mechanism of alkali metals on unburned coal and the destruction mechanism of alkali metals on carbon crystals were discussed. It can provide reference for reducing alkali metal corrosion on coke and improving pulverized coal utilization rate.     

Combustion of particles in a large pulverized brown coal flame

A model of the ignition of a polydisperse cloud of brown coal particles, in a known gas environment, is presented and used to predict the behavior of the particles in a burner jet of a utility boiler. The model allows for drying, devolatilization, and char combustion of the particles. It is assumed that the volatiles burn in the free stream so that char combustion can occur during volatiles evolution, the diffusion of oxygen to the particle surface being inhibited due to the net outflow of volatiles. The model is used to calculate the behavior of a cloud of p.f. size particles along the centerline of a brown coal burner jet in which the gas temperature and composition have been measured. Rates of volatile release and char combustion are calculated and shown to be in agreement with measurements of volatile material in the flame. It is found that particles smaller than about 80 μm contribute most to the ignition of the jet and that they closely follow the local gas temperature. The unique character of brown coal of combustion, its high volatile evolution on rapid heating, the high activity of its char at low temperature, and the demonstrated ignition of its char without a jump in temperature make the overlap of devolatilization and char combustion more likely than with other coals. The mathematical formulation that allows this overlap gives oxygen consumption levels consistent with measurement. An analysis is made of the relative importance of radiation from the flame front to the particle, and entrainment of hot combustion gases into the jet. It is found that the radiation is of secondary importance compared to the effect of entrainment which is the controlling mechanism in the initial heating of the particles. Also, the significance of the assumption that the volatiles burn in the free stream is discussed.     

格栅型煤粉分配器的分配特性研究

为了研究格栅型煤粉分配器的均匀分配效果,在分配器入口前加设一段弯管以形成分配器入口气固两相流动的非均匀条件,利用Fluent软件对不同格栅数的煤粉分配器的性能进行数值模拟,得到其内部流动情况以及颗粒运动状态。结果表明:在两级格栅出口转角处磨损严重,在流通截面扩大处磨损较小;每根支管的出口速度都不均匀。随着格栅数增加,各出粉支管之间的流动偏差减小,8格栅时偏差最小,同时也能够满足送粉工况对煤粉分配器初始分配均匀性的要求。颗粒的运动在"主流区"内跟随性好,而在"主流区"外运动较随机;格栅出流方向的不同顺序对流动偏差影响不大。另外,煤粉分配器的进口风粉分布和出口送粉管道的阻力特性会对分配器的初始分配效果产生不同程度的影响。