75t/h循环流化床锅炉循环回料不稳浅析

CFB锅炉的回料系统堵塞现象对CFB锅炉运行的稳定性,经济性影响很大。本文通过对回料系统堵塞现象的分析给CFB锅炉的稳定运行提供了必要的理论依据。     

循环流化床锅炉输煤系统的改造

就黄陵煤矸石热电有限公司输煤系统存在的问题进行研究,通过对原系统和改造后系统的分析,分别从输煤系统的出力的改善、煤的筛分、煤的粒度对锅炉运行的影响,输煤系统的节能运行等方面进行分析研究。通过系统改造,保证锅炉的燃煤的需要,改善燃煤的粒度,促进锅炉稳定燃烧,延长运行周期;同时改善现场的环境,降低职工工作强度,具有较好的节能效果。     

镇海发电厂输煤系统的改造

阐述了镇海发电厂输煤系统中的桥式卸煤机、斗轮堆取料机、卸料车等设备的综合改造情况．介绍了应用可编程序控制器对输煤系统实行监测和控制的改进工作。改进后使设备发挥了更大潜力．增加了卸煤生产率和节约了能耗。     

筛分破碎一体碎煤机室布置研究

筛碎系统是循环流化床锅炉发电厂燃料处理的重要环节,筛碎系统对来煤的破碎处理以及对入炉煤粒度的控制直接影响循环流化床锅炉的燃烧稳定以及锅炉燃烧效率,进而影响整个电厂的运行及经济效益的优劣。本文通过我院设计的东源热电项目运煤系统中碎煤机室的设计优化方案比较,讨论筛碎一体式碎煤机在循环流化床锅炉电厂运煤系统中的使用特点及适用范围。     

一期输煤程控上位机自动配煤出错简析

基于ABPLC控制的输煤程控系统，实现了整个输煤设备运行过程的集中控制，高效可靠的完成着燃煤的卸载、储存、供应工作，改善了运行人员的工作环境。通过程序控制，使输煤系统各个环节自动化运行，如皮带机自启停、取料机自动取煤、煤仓自动配煤、设备故障联锁跳机等，大幅度降低了燃料人员的工作强度，提高了输煤系统的可靠性。但程序设计受网络延时等不确定因素影响也会产生漏洞，本文特针对一期输煤程控上位自动配煤偶尔出错，进行简要分析及处理。     

大型循环流化床锅炉内置式分离器结构优化研究

循环流化床燃烧（CFBC）作为一种最具发展前景的“洁净”煤燃烧技术,正在向着更高的参数、更大的容量发展。国外发达国家都在争先开发600MW以上容量超临界蒸汽参数的大型循环流化床锅炉。本文对CFB锅炉的大型化内置式分离器结构进行了系统分析,并提出了一种新的循环流化床锅炉大型化内置式分离器结构优化方案。     

ZQX600桥式抓斗卸船机输煤系统设计

介绍了ZQK600桥式抓斗卸船机输煤系统中煤斗及其斗壁上振动破拱装置的振动特点;对调频振动给料机的优点及其使用注意事项作了说明,在调频振动给料机上加设条形分离筛后可取代传统的滚轴筛,大大减轻了设备重量,起到了很好效果;最后分析该输煤系统的不足之处,提出了改进方法。     

MODICON PLC在输煤程控系统上的应用

输煤系统为电厂环境最恶劣的生产场所,要求对控制系统可靠性高,操作、维护方便。根据我厂特点,介绍Modicon Quantum PLC在热电厂输煤程控系统上的改造应用,提高电厂自动化程度,有效的保证锅炉上煤的稳定性、可靠性。     

环式给煤机在纳雍电厂的应用探析

本文首先简要概述了环式给煤机的涵义特点,以纳雍电厂环式给煤机为例,分析了环式给煤机存在的问题,从承煤盘撒煤、承煤盘积煤、卸煤车出力不足三个方面,阐述了环式给煤机的技术改造方法,通过将单侧犁煤器改为双侧犁煤器等措施,确保电厂输煤系统的稳定运行。     

上海市某社会福利院蓄热系统设计

介绍了蓄热电锅炉系统的设计,分析了项目中电锅炉蓄热系统的热负荷及其系统设备配置,并针对上海市电价政策,制定了蓄热系统的运行策略。通过与燃煤式、燃油式锅炉经济性比较,蓄热电锅炉自动化程度高、无噪声,且运行费用低,具有一定的应用前景。     

Design optimization of the bell type blast cap employed in small scale industrial circulating fluidized bed boilers

Blast cap is the key component of air distributor in circulating fluidized bed (CFB) boilers. Its configuration and performance affects the fluidization quality of the bed, as well as the boiler performance. With the advantage of controlling the jet penetration characteristics and the resistance coefficient individually, bell type blast cap has been widely applied in big-scale utility CFB boilers. Moreover, the inner circuitous gas pass of the bell-type blast cap is able to prevent the bed material from flowing backward into the air chamber effectively, and its tube shield is also convenient to be maintained and replaced. Consequently, the bell-type blast cap is also fit for the small scale industrial CFB boilers with lower operation and maintenance levels in spite of higher manufacturing cost. At present, bell type blast cap is mainly applied in the large scale utility CFB boilers, seldom employed in the small scale industrial CFB boilers with lower bed pressure drop. In the study, aim to acquire favorable fluidization quality and reasonable pressure drop of the bed of small scale industrial CFB boiler, the air jet penetration characteristics of the bell type blast cap were investigated in static beds composed of two typical solids in CFB individually, and the impacts of the inner configuration on blast cap’s resistance characteristics were studied via numerical simulation. The detailed design principle and approach of bell type blast cap was proposed finally based on the study results.     

Corrosion evaluation of one dry desulfurization equipment – Circulating fluidized bed boiler

As a clean fuel combustion technology, circulating fluidized bed (CFB) possesses various advantages. Among them, flexibility in fuels and superiority in desulfurization are the two prominent ones and can hereby facilitate sufficient utilization of high-sulfur fuels. But unfortunately, these low-grade fuels always introduce harsh service environment within the CFB boilers and consequently result in severe degradation extent on relevant equipments, especially the high-temperature sulfur corrosion. In this event, by nearly ten characterization methods, comprehensive investigation was carried out on a whole CFB boiler during downtime, and special emphasis was particularly laid on the failure components including one perforated nozzle along with its fractured inlet tube for primary air, and one perforated manhole door of refeed valve. Finally, countermeasure and suggestion was put forward, which can provide instructive significance in corrosion prevention for the CFB boilers, even other desulfurization equipments, running under similar aggressive conditions in engineering practice.     

Study on scale-up characteristics of oxy-fuel combustion in circulating fluidized bed boiler by 3D CFD simulation

The oxy-fuel combustion CFB technology as a promising carbon capture technologies needs to study the scale-up process for the commercial diffusion. Numerical simulation would be a rational tool to investigate the gas-solid flow and oxy-fuel combustion process before constructing an expensive and complicated industry-scale plant. A three-dimensional (3D) CFD simulation according to the Eulerian-Lagrangian approach was applied to simulate the hydrodynamics of gas-solid flow and oxy-fuel combustion process in lab-scale, pilot-scale and industry-scale CFB boiler (from 0.1 MW_th to 330 MW_e). Results present the differences of the boiler configuration, the gas-solid flow and the oxy-fuel combustion characteristics between lab-scale, pilot-scale and industry-scale CFB boilers. The cross-section thermal load gradually decreased, while the cross-section area increased with the thermal inputs increased. In the lab-scale and pilot-scale oxy-fuel CFB, the particle velocity field was more uniform than that in the industry-scale CFB. The carbon conversion ratio increased with an increase in the thermal input. The emission of CO, NO and SO₂ in the industry-scale oxy-fuel CFB boilers was lower than those in the lab-scale and pilot-scale. A larger oxy-fuel combustion power plant is beneficial to carbon capture and low pollutant emission. The results would be beneficial to the design and operation of industry-scale oxy-fuel CFB.     

煤块冲击破碎粒度的分形特征

煤块冲击破碎后的粒度分布具有分形特征,根据分形理论建立了煤块冲击破碎粒度的分形模型,对不同矿区的煤块进行冲击破碎试验。在不同试验条件下对冲击破碎后煤块的筛下质量累积概率进行函数拟合,拟合结果表明分形模型能够很好地描述煤块冲击破碎后的粒度分布特征,粒度分形维数是评价煤块冲击破碎效果的重要参数。采用Matlab软件建立了粒度分形维数与试验参数之间的二次方模型,该模型的预测结果与试验结果的平均误差为2.51%,满足预测误差要求,为控制煤块冲击破碎后的产品粒度分布提供了理论依据。     

A technique to quantify morphological damage of the flute profile in the midplane of corrugated fibreboard

This research presents a technique to quantify morphological damage to flutes in corrugated fibreboard (CFB). The method involves laser cutting thin samples and analysing digital images of the flute profiles. The surface profiles of creased CFB before and after laser cutting were measured using fringe projection and showed that the sample preparation does not significantly affect the flute profile. After imaging the laser cut samples, skeleton analysis was used to derive a digitised profile of the flute shape. To characterise the level of damage to the flute profile, a similarity factor (SF) was introduced to quantify the relative difference between test sample and reference flute profiles. Validation of this analysis technique was done by generating known images of flute profile with variations that include distortions that could occur to CFB. These images were then fed into the skeleton analysis, and the results were compared with the original profile. This comparison showed good agreement between the initial and skeleton‐analysed flutes. A demonstration of the skeleton analysis on purposefully damaged actual CFB flute profiles shows that the SF reduces as the level of crushing increases, showing that the technique could be used to enumerate morphological damage to CFB during manufacture, conversion, and use.     

静态破碎剂的配方优化设计与水化反应分析

为探究各组分含量变化对静态破碎剂水化反应速率的影响,确定静态破碎剂各组分的最优配比,基于单因素多水平试验,运用正交试验对静态破碎剂进行配方优化。进行了静态破碎剂水化反应速率分析和混凝土破碎验证试验。试验结果表明:静态破碎剂各组分质量分数区间为氧化钙70%~80%、P ·O 42.5水泥（水泥）8%~12%、硫酸钙（石膏）2%~ 4%、钠基膨润土3%~ 7%;不足100%部分中,除1%减水剂外,由粉煤灰作为填充剂补充。确定静态破碎剂最优配方（质量分数）为氧化钙73%、水泥10%、石膏5%、钠基膨润土6%、减水剂1%、粉煤灰5%。配方优化后,自制静态破碎剂的混凝土破碎效果优于商用静态破碎剂。     

Investigation on tectonically deformed coal particle crushing by DEM under triaxial loading: Implication for coal and gas outburst

Tectonically deformed coal is composed of loosely bonded and brittle particles. The effect of particle crushing on tectonically deformed coal was studied through triaxial loading tests using the discrete element method. Coal particles are highly sensitive to crushing under confining pressure. When confined pressure at 2.5 MPa, the sample behaves similarly to an uncrushed sample. The majority of boundary work is consumed by particle friction and crushing during loading. The porosity increases obviously, the granular system is transferred into fluid-like state. With an increase in confining pressure, particle crushing intensifies, resulting in a growth in weak force chains and crushing energy, and a decrease in porosity. The pattern of particle crushing is closely linked to specific force chains. Particle rotation is a significant factor affecting particle crushing, and it hinders the connection of shear zones. Crushed particles decrease porosity by filling the gaps between larger particles. After compaction, crushed particles form a crushing and compaction belt, which creates local gas sealing conditions and makes gas extraction difficult in tectonically deformed coal areas. These characteristics play a crucial role in understanding how in-situ stress impacts gas outbursts and the difficulty of gas extraction.     

航空发动机双转子系统高/低压涡轮碰摩振动分析

针对航空发动机碰摩问题,考虑高压涡轮与低压涡轮碰摩,建立了五点支承的航空发动机双转子系统动力学模型。碰摩力模型采用Lankarani-Nikravesh滞回力模型。利用龙格-库塔法进行数值计算,并研究了双转子系统的频谱特性、幅频特性。最后,基于双转子实验台,部分验证了数值计算结果。结果表明:(1)双转子系统碰摩会使系统产生激励频率以及组合频率,并发生组合共振;(2)高压涡轮碰摩会导致系统产生反向涡动全周碰摩,低压涡轮碰摩对高压涡轮碰摩有抑制作用,即高低压涡轮同时碰摩时与高压涡轮碰摩时相比,系统发生反向涡动的转速区间更窄、振动幅值更低;(3)在升降速过程中,碰摩会导致双转子系统出现单个甚至多个双稳态现象。     

煤块冲击破碎速度研究

冲击破碎速度是影响煤块冲击破碎效果的主要参数。基于分段塑变碰撞模型得到煤块与冲击板碰撞时的接触应力,并结合裂缝假说和能量守恒原理推导出煤块被破碎到指定粒度需要的理论冲击速度。进行煤块冲击破碎试验,通过试验数据分析得到了冲击破碎速度的试验拟合公式和理论修正公式。88%的拟合计算值与试验值的误差小于10%,但拟合公式结构复杂,不适合工程应用;85%的理论修正值与试验值的误差小于20%,满足初级破碎所需的精度,可以作为初级破碎时冲击破碎速度的理论选择依据。     

电厂锅炉入炉煤采制样不确定度分析与模拟

为研究采制样过程引起的锅炉入炉煤发热量不确定度,在6个电厂的17台锅炉上进行了入炉煤实际采制样实验,研究了采制样样品发热量的分散特性;利用浓度方差表示煤质的均匀性,建立了入炉煤采制样装置样品特性随机模型,根据实际采制样实验对模型进行标定,用于定量分析混煤煤质均匀性对入炉煤发热量不确定度的影响,在此基础上,研究了入炉煤煤量加权平均发热量的测量特性。结果表明,不同锅炉采制样环节引起入炉煤发热量不确定度在1.0～4.82 MJ/kg;采制样装置样品随机模型能够较准确描述采样样品特性;混煤煤质均匀性越差,采制样引起的入炉煤发热量不确定度越大;当加权为90天时,煤量加权平均发热量的扩展不确定度从原来的2.321 kJ/kg减少到0.243 kJ/kg。