Experimental Study on Ammonia Co-Firing with Coal for Carbon Reduction in the Boiler of a 300-MW Coal-Fired Power Station

To reduce CO_(2) emissions from coal-fired power plants,the development of low-carbon or carbon-free fuel combustion technologies has become urgent.As a new zero-carbon fuel,ammonia(NH_(3))can be used to address the storage and transportation issues of hydrogen energy.Since it is not feasible to completely replace coal with ammonia in the short term,the development of ammonia-coal co-combustion technology at the current stage is a fast and feasible approach to reduce CO_(2) emissions from coal-fired power plants.This study focuses on modifying the boiler and installing two layers of eight pure-ammonia burners in a 300-MW coal-fired power plant to achieve ammonia-coal co-combustion at proportions ranging from 20%to 10%(by heat ratio)at loads of 180-to 300-MW,respectively.The results show that,during ammonia-coal co-combustion in a 300-MW coal-fired power plant,there was a more significant change in NO_(x) emissions at the furnace outlet compared with that under pure-coal combustion as the boiler oxygen levels varied.Moreover,ammonia burners located in the middle part of the main combustion zone exhibited a better high-temperature reduction performance than those located in the upper part of the main combustion zone.Under all ammonia co-combustion conditions,the NH_(3) concentration at the furnace outlet remained below 1 parts per million(ppm).Compared with that under pure-coal conditions,the thermal efficiency of the boiler slightly decreased(by 0.12%-0.38%)under different loads when ammonia co-combustion reached 15 t·h^(-1).Ammonia co-combustion in coal-fired power plants is a potentially feasible technology route for carbon reduction.

Optimizing Two-Phase Flow Heat Transfer:DCS Hybrid Modeling and Automation in Coal-Fired Power Plant Boilers

In response to escalating challenges in energy conservation and emission reduction,this study delves into the complexities of heat transfer in two-phase flows and adjustments to combustion processes within coal-fired boilers.Utilizing a fusion of hybrid modeling and automation technologies,we develop soft measurement models for key combustion parameters,such as the net calorific value of coal,flue gas oxygen content,and fly ash carbon content,within theDistributedControl System(DCS).Validated with performance test data,thesemodels exhibit controlled root mean square error(RMSE)and maximum absolute error(MAXE)values,both within the range of 0.203.Integrated into their respective automatic control systems,thesemodels optimize two-phase flow heat transfer,finetune combustion conditions,and mitigate incomplete combustion.Furthermore,this paper conducts an in-depth exploration of the generationmechanismof nitrogen oxides(NOx)and low oxygen emission reduction technology in coal-fired boilers,demonstrating a substantial reduction in furnace exit NOx generation by 30%to 40%and the power supply coal consumption decreased by 1.62 g/(kW h).The research outcomes highlight the model’s rapid responsiveness,enabling prompt reflection of transient variations in various economic indicator parameters.This provides a more effective means for real-time monitoring of crucial variables in coal-fired boilers and facilitates timely combustion adjustments,underscoring notable achievements in boiler combustion.The research not only provides valuable and practical insights into the intricacies of two-phase flow heat transfer and heat exchange but also establishes a pioneering methodology for tackling industry challenges.

INTRODUCTION TO INCONEL ALLOY 740: AN ALLOY DESIGNED FOR SUPERHEATER TUBING IN COAL-FIRED ULTRA SUPERCRITICAL BOILERS

Chinese utilities as well as those worldwide are facing increased demand for additional electricity, reduced plant emissions and greater efficiency. To meet this challenge will require increasing boiler temperature, pressure and coal ash corrosion resistance of the materials of boiler construction of future coal-fired boilers. A new nickel-based tube alloy, INCONEL^R alloy 740, is described aiming at meeting this challenge. Emphasis will be on describing the alloy＇ s mechanical properties, coal-ash and steam corrosion resistance. Microstructural stability as a function of temperature and time is addressed as well as some of the early methodology em- ployed to arrive at the current chemical composition.

NO_x emission model for coal-fired boilers using partial least squares and extreme learning machine

To implement a real-time reduction in NOx,a rapid and accurate model is required.A PLS-ELM model based on the combination of partial least squares(PLS)and the extreme learning machine(ELM)for the establishment of the NOx emission model of utility boilers is proposed.First,the initial input variables of the NOx emission model are determined according to the mechanism analysis.Then,the initial input data is extracted by PLS.Finally,the extracted information is used as the input of the ELM model.A large amount of real data was obtained from the distributed control system(DCS)historical database of a 1 000 MW power plant boiler to train and validate the PLS-ELM model.The modeling performance of the PLS-ELM was compared with that of the back propagation(BP)neural network,support vector machine(SVM)and ELM models.The mean relative errors(MRE)of the PLS-ELM model were 1.58%for the training dataset and 1.69%for the testing dataset.The prediction precision of the PLS-ELM model is higher than those of the BP,SVM and ELM models.The consumption time of the PLS-ELM model is also shorter than that of the BP,SVM and ELM models.

Feasibility Analysis on the Integrated Application of Solar Energy, Biogas, Coal-fired Boiler and Radiant Floor Heating for Rural Residence

The feasibility of adopting a balanced energy mix mode (domestic solar energy, biogas, coal-fired boiler and radiant floor heating) was proposed. Taking a typical rural residence in Zhengzhou City for example, the study through theoretical analysis and calculation showed that such a balanced energy mix is an economic way and efficient in saving energy and reducing air pollution, and elaborated the theoretical feasibility of popularizing such a heat supply mode in rural areas.

System Performance and Pollution Emission of Biomass Gas Co-Firing in a Coal-Fired Boiler

To reduce greenhouse gases emission and increase the renewable energy utilization portion in the world, the biomass gasification coupled with a coal-fired boiler power generation system is studied. It is a challenge to achieve optimum performance for the coupled system. The models of biomass gasification coupled with co-firing of coal in a boiler have been established. A comparative study of three kinds of biomass (Food Rubbish, Straw and Wood Pellets) has been done. The syngas produced in a 10 t/h gasifier is fed to a 330 MWe coal-fired boiler for co-combustion, and the co-firing performances have been compared with pure coal combustion case under the conditions of constant boiler load. Results show that co-firing decreases the furnace combustion temperature and raises the flue gas temperature for Food Rubbish and Straw, while, flue gases temperature decrease in case of Wood Pellets. At the same time NOx and SOx emissions have reduced. The system efficiencies at constant load for Food Rubbish, Straw and Wood Pellets are 83.25%, 83.88% and 82.56% when the optimum conditions of gasification and co-firing process are guaranteed.

Comprehensive evaluation for efficient development of coal-fired Industry boiler clearing

The Paper has introduced development of domesticand foreign coal-fired industry boiler and has implementedcomprehensive comparison for several substitution technologies（coal powder boiler, coal water mixture boiler, coal-fired boiler,gas-fired boiler and biomass boiler, etc.） of backward coal-firedindustrial boiler in technology, economy and environment, etc.;has evaluated comprehensive effect and adaptiveconditions of coal-fired industry boiler technology and has put forward suggestion forefficient development of coal-fired industry boiler clearing.

Analysis of Prese nt Operating Situati on of Large Size Coal-F ired Utility Boilers

Large size utility boilers develop rapidly in China, both their reliability and economics have reached better level. The operating situations of various existing boilers on the basis of different coals are analyzed, it is held that, the notable energy imbalance of furnace exit, ever existing in the tangential firing boilers has been solved, with comparatively lower NOX emission concentration of gained. The higher NOX emission concentration and furnace slagging etc. problems existing in wall firing boilers are notable. The comprehensive analysis shows that, it is appropriate to choose lower furnace volume heat release rate and higher flame height in the type selection design of boilers, and sufficient margin should be kept in the selection of coal pulverizing mills.

Flexibility of a 300 MW Arch Firing Boiler Burning Low Quality Coals

Experimental investigations on the flexibility of a 300 MW Arch Firing (AF) coal-fired boiler when burning low quality coals is reported. Measurements of gas temperature and species concentration and char sampling using a water-cooled suction pyrometer were carried out along the furnace elevation. The carbon content and the size distribu-tions of the char samples were obtained. The char morphology was examined using a field emission scanning electron microscope (FESEM). The char sampling was performed on this type of boiler for the first time. The results indicate that the flexibility of this boiler burning low quality coals under a moderate boiler load is better than its flexibility under a high boiler load. Because of the insufficient capacity of the coal pulverizers used,in case of low coal quality the pul-verized coal fineness will drastically decrease under high boiler loads. This causes an increase in the loss due to incom-plete mechanical and chemical combustion. This is the main cause of a low burnout degree of the pulverized coal and the decrease of the flexibility of this AF boiler under a high boiler load.

Development of 600 MW Class Coal Fired Boilers in China

This article introduces the present status anddevelopment of 600 MW class boilers in China. The statisticaldata indicate that most 600 MW generating units experiencedrelatively length" growing up" period. In this period, unitscould not operate stably , their unplanned outage times weremany and durations long, and availabilities low. On the basis oftesting and research and the summing-up of practice, it wasindicated slagging in the furnace, deviation of tine gas energy atthe exit of furnace, and overheating bursting of superheater andreheater etc, endangering the safety and economics ofoperation,main problems could be completely alleviated oravoided through design and type selection of boiler furnace andburners, coal characteristics and coal handling management,and optimization management of operation conditions etc.

Study and Application of W-Flame Boiler Startup Aided by Adjacent Hot Primary Air

In this paper,the designed features of a W-flame coal-fired boiler are introduced.A scheme of joint primary air for two boilers is made and technical measures are also taken based on corresponding analyses and studies.The scheme and the measures provide a reference for technicians to improve the efficiencies and reduce the startup costs of other similar large boilers.

机器人锅炉冷态空气动力场测量系统开发

针对锅炉冷态空气动力场试验自动化程度低、操作危险性大的问题,开发了机器人锅炉冷态空气动力场试验测量系统。系统下位机采用STM32芯片作为主控芯片,控制爬壁机器人的运动以及与上位机的信息交换,同时引入混沌线性惯性权重对粒子群优化模糊PID算法进行优化,并将改进后的算法作为机器人运动路径的控制策略,对于机械臂的控制引入D-H法。上位机为LabVIEW搭建的操作平台,通过嵌入双树复小波变换去噪算法,对采集到的风速信号进行降噪处理。结果表明:所提出的系统各个模块均可正常且稳定运行,与人工测试的误差保持在±10%,能够满足锅炉冷态试验的要求。

深度调峰灵活性锅炉改造措施分析探讨

目前火力发电厂频繁地进行调峰操作已成常态,随着风电、光伏等新能源在能源结构中所占比重不断提高,为保证电网能够在高峰期和低谷期之间平稳运转,调峰备用电源的重要性变得越来越明显。本文阐述了调峰过程中保证锅炉安全运行的改造措施,锅炉燃烧侧稳定措施、宽负荷脱硝保证措施,保证受热面安全性的措施及其他运行措施等在进行深度调峰改造时,应综合考虑电厂机组特点、改造历史、运行状况以及耗材来源等条件,以选择具体可行的技术改造方案。

我国工业锅炉行业绿色转型路径探讨

工业锅炉是我国化石能源消耗的主要设备之一,也是主要的CO_(2)排放源,在国家碳中和愿景下面临着绿色转型的紧迫压力。文章揭示了我国工业锅炉行业发展现状,结合文献计量方法和政策研究,分析了新时期我国工业锅炉行业发展面临的挑战与机遇,提出围绕能源转型和数字化转型的发展路径与创新方向对策,为行业转型升级、绿色低碳发展提供支撑。

中南股份炼钢厂1号、2号转炉余热锅炉改造实践

余热锅炉回收系统是转炉生产的关键环节,随着转炉高产低耗绿色发展的要求,转炉余热锅炉系统效率的提升尤显重要。针对转炉余热锅炉频繁爆管、蒸汽回收量低、维护工作量大、环境污染严重等问题,通过对转炉余热锅炉系统尾部烟道及高压除氧器等进行改造,采用新型纳米保温材料,优化热力管道走向等技术改造措施,稳定转炉余热锅炉系统的运行,提高蒸汽回收量,实现转炉生产稳定、安全的目的。

超小断面切圆锅炉宽煤种适应性燃烧改造

超小断面切圆贫煤锅炉在掺烧烟煤时存在结渣严重、高温腐蚀等问题,为适应当前煤炭市场多元化及锅炉灵活性运行等需求,亟待提升其对复杂煤种掺烧的适应性。以某电厂300 MW超小断面四角切圆燃烧锅炉为研究对象,开展煤种适应性燃烧改造研究。首先,利用CFD数值模拟方法评估出锅炉原燃烧系统在掺烧烟煤时存在的燃烧问题,从而针对性地提出燃烧系统改造方案,通过增加燃烧器间距降低燃烧器区域热负荷、减小假想切圆解决火焰刷墙、增加燃尽风率实现深度空气分级等措施,拓展锅炉对煤质的适应能力;进而运用CFD数值模拟方法确定了该燃烧改造方案最佳的性能参数,预测了燃烧改造后锅炉在掺烧67%及100%低灰熔融温度烟煤下的燃烧状态,并通过工程试验验证了该燃烧改造的有效性。结果表明,燃烧改造后该300 MW超小断面四角切圆燃烧锅炉燃用煤质可由原掺烧20%烟煤到适应掺烧67%~100%低灰熔融温度烟煤,有效增强了煤种适应性。经第三方考核试验,改造后燃用设计煤工况锅炉效率提高2.25%、NO_(x)排放率降低40%~48%、炉膛未出现明显结渣及高温腐蚀问题。该燃烧改造方案为国内原设计贫煤的切圆燃烧锅炉拓展烟煤适应性提供借鉴。

基于重力热管的锅炉供热系统节能改造

为进一步降低锅炉供热系统的排烟温度,提高对余热的回收效率,达到节能减排的目的,基于重力热管对锅炉供热系统进行节能改造。利用重力热管对锅炉的烟气余热系统进行改造,提升锅炉供热系统的节能效果。介绍了重力热管换热器的设计、原理、结构及安装,分析了节能改造效果。节能改造后,锅炉供热系统可回收热量57622.4 kJ/h,每个采暖季可节约成本8985.6元,锅炉供热系统的经济性有效提升。

Application of Response Surface Methodology for Analysis of Reheat Steam Temperatures in a Double Reheat Coal-Fired Boiler

For the improvement of reheat steam quality and performance of double reheat coal-fired utility boiler under wide load operation, a variety of temperature regulation ways were utilized to adjust the energy distribution between different heating surfaces. In this paper, thermodynamic calculation based on the fundamental heat transfer theory was conducted for the analysis of temperature regulation strategy effects to steam temperature. In consideration of the specific overlapping heating surface arrangement, the compartment model was adopted to solve this problem. Response surface methodology(RSM) was used to analysis the effect of each temperature regulating variables on the steam temperature and boiler efficiency;then the polynomial model was fitted to predict the primary and secondary steam temperature simultaneously. Results showed that the flue gas recirculation rate has a relatively significant influence on the steam temperature, the maximum temperature deviation between fitting value and calculation value is 3.85℃ in 75% THA;the quadratic model can well predict the steam temperature under different operation conditions in wide load change. The variation of flue gas baffle has a significant influence on the boiler efficiency, compared to the flue gas recirculation and angle of burner oscillation. The influence of various factors on the reheat steam temperature is flue gas baffle > flue gas recirculation > angle of burner oscillation.

循环流化床锅炉超低排放改造分析及应用

文章分析了循环流化床锅炉在排放高含硫量的烟气时的超低排放改造(脱硝、脱硫、除尘、除雾)技术,介绍了某2×130t/h循环流化床锅炉的改造情况。

FGR技术对燃气锅炉出力、热效率及生成NO x的影响分析

介绍了燃气工业锅炉氮氧化物(NO x)的生成机理,分析了燃气锅炉排放NO x的主要来源。介绍了烟气再循环技术的工作原理,通过开展烟气再循环技术对燃气热水工业锅炉燃烧过程调控作用实验,研究了烟气再循环技术对锅炉出力、热效率及生成NO x的影响规律。实验结果表明,随着烟气再循环开启火焰温度降低,使得锅炉出力、热效率降低,同时热力型NO x的生成被抑制,造成NO x生成总量下降。