Corrosion Behavior of TP316L of Superheater in Biomass Boiler with Simulated Atmosphere and Deposit

Corrosion behavior of TP316L was investigated with simulated atmosphere and ash deposition for the superheater in biomass boiler.Corrosion dynamic curves were plotted by mass gain.The results showed that the corrosion was dependent on temperature and was greatly accelerated by ash deposition.The mass gain was distinctly reduced in the presence of SO2 with and without ash deposition on the specimens.Corrosion rates with ash deposit at different temperatures were calculated.Two feasible methods were provided to avoid serious high-temperature corrosion in the biomass boiler.

Study on Fuzzy Self-Adaptive PID Control System of Biomass Boiler Drum Water

The paper discusses the features of the Biomass Boiler drum water level. Conventional PID Control System can not reach a satisfaction result in nonlinearity and time different from Biomass Boiler Drum Water Control System. In this study, a kind of fuzzy self-adaptive PID controller is described and this controller is used in biomass boiler’s drum water level control system. Using the simulink tool of MATLAB simulation software to simulate the fuzzy adaptive PID and conventional PID control system, the result of the comparison shows that the fuzzy self-adaptive PID has the strong anti-jamming, flexibility and adaptability as well as the higher control precision in Biomass Boiler Drum Water.

Biomass briquette fuel,boiler types and pollutant emissions of industrial biomass boiler:A review

Biomass is considered a renewable and cleaner energy source alternative to fossil fuels.In recent years,industrial biomass boilers have been rapidly developed and widely used in the industrial field.This work makes a review on the fuel types used in industrial biomass boilers,the fuel characteristics and the characteristics of air pollutants emitted from the combustion of industrial biomass boilers and other contents in different studies.However,the existing research still has many deficiencies.In the future,further research on biomass fuel,industrial biomass boiler combustion process and the pollutants emitted by industrial biomass boiler combustion,especially the carbonaceous aerosol emitted by in-dustrial biomass boiler and carbonaceous aerosol optical properties still need to be made.At the same time,the potential harm of carbonaceous aerosols emitted from industrial biomass boiler sources to human health and climate change needs to be studied in depth.This review provides a scientific basis for the accurate evaluation of industrial biomass boilers and the effective prevention and control of various pollutants of industrial biomass boilers.

Characteristics of particulate-bound polycyclic aromatic hydrocarbons emitted from industrial grade biomass boilers

Polycyclic aromatic hydrocarbons（PAHs） are carcinogenic or mutagenic and are important toxic pollutants in the flue gas of boilers. Two industrial grade biomass boilers were selected to investigate the characteristics of particulate-bound PAHs： one biomass boiler retro-fitted from an oil boiler（BB1） and one specially designed（BB2） biomass boiler. One coal-fired boiler was also selected for comparison. By using a dilution tunnel system, particulate samples from boilers were collected and 10 PAH species were analyzed by gas chromatography–mass spectrometry（GC–MS）. The total emission factors（EFs） of PAHs ranged from 0.0064 to0.0380 mg/kg, with an average of 0.0225 mg/kg, for the biomass boiler emission samples. The total PAH EFs for the tested coal-fired boiler were 1.8 times lower than the average value of the biomass boilers. The PAH diagnostic ratios for wood pellets and straw pellets were similar.The ratio of indeno（1,2,3-cd）pyrene/[indeno（1,2,3-cd）pyrene ＋ benzo（g,h,i）perylene] for the two biomass boilers was lower than those of the reference data for other burning devices, which can probably be used as an indicator to distinguish the emission of biomass boilers from that of industrial coal-fired boilers and residential stoves. The toxic potential of the emission from wood pellet burning was higher than that from straw pellet burning, however both of them were much lower than residential stove exhausts.

Application of a Lumped Multi-Section Model for Analyzing the Thermal Performance of a Small-Scale Biomass Boiler

The stationary lumped-cell model was developed and used to simulate the thermal characteristics of domestic biomass boiler with helically coiled tube heat exchanger(HCHE).The device serves as the heat source for ORC(Organic Rankine Cycle)unit and utilizes the thermal oil as the medium transferring the heat to the unit.Most of studies available in the literature refer to the CFD simulations for water flow in tube coils or in one-or two-turn coil elements.These investigations are basically focused on the determination of Nusselt number.The proposed herein model aims at determining the thermal performance of flue gas-oil HCHE while providing low CPU time.To demonstrate the model possibilities,it was used to predict the flue gas temperatures at the inlet and outlet from the heat exchange zone,based on measurement data regarding the outlet temperature of thermal oil.Six test series were considered.The computation results appeared to be in satisfactory agreement with experimental results(the discrepancies do not exceed 12%).The investigations showed that the used approach may be recommended as an alternative method that allows for fast prediction of thermal parameters for units of complex geometries,in particular the multi-coil heat exchangers.

Emission factors, ozone and secondary organic aerosol formation potential of volatile organic compounds emitted from industrial biomass boilers

To evaluate the potential benefits of biomass use for air pollution control, this paper identified and quantified the emissions of major reactive organic compounds anticipated from biomass-fired industrial boilers. Wood pellets(WP) and straw pellets(SP) were burned to determine the volatile organic compound emission profiles for each biomass-boiler combination. More than 100 types of volatile organic compounds(VOCs) were measured from the two biomass boilers. The measured VOC species included alkanes, alkenes and acetylenes, aromatics, halocarbons and carbonyls. A single coal-fired boiler(CB) was also studied to provide a basis for comparison. Biomass boiler 1(BB1) emitted relatively high proportions of alkanes(28.9%–38.1% by mass) and alkenes and acetylenes(23.4%–40.8%),while biomass boiler 2(BB2) emitted relatively high proportions of aromatics(27.9%–29.2%)and oxygenated VOCs(33.0%–44.8%). The total VOC(TVOC) emission factors from BB1(128.59–146.16 mg/kg) were higher than those from BB2(41.26–85.29 mg/kg). The total ozone formation potential(OFP) ranged from 6.26 to 81.75 mg/m^3 with an average of 33.66 mg/m^3 for the two biomass boilers. The total secondary organic aerosol potential(SOAP) ranged from 61.56 to 211.67 mg/m^3 with an average of 142.27 mg/m^3 for the two biomass boilers.The emission factors(EFs) of TVOCs from biomass boilers in this study were similar to those for industrial coal-fired boilers with the same thermal power. These data can supplement existing VOC emission factors for biomass combustion and thus enrich the VOC emission inventory.

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.

Flexible Co-Combustion of High Ratios of Sustainable Biomass with Coal in Oxy-CFB Boiler for CO₂Capture

Coal-fired plants are under pressure to reduce their carbon-intensity. Available options include co-firing CO2-neutral biomass, oxy-fuel-combustion as part of a carbon capture process or a combination of both to give a “CO2-negative” power plant. BioCCS, the combination of CO2 Capture and Storage (CCS) with sustainable biomass conversion, is the only large-scale technology that can achieve net negative emissions. Combining, developing and demonstrating the oxy-combustion of high ratios of sustainable biomass with coal in flexible circulating fluidized bed (CFB) boiler will bring significant advances in the reduction of greenhouse gases (GHG) emissions. Areas addressed include possibilities for: biomass characterization;handling and feeding;co-firing ratios definition;CFB oxy-co-combustion studies;combustion performance;boiler flexibility in fuel and load;main emissions analysis;slaging, fouling and agglomeration;corrosion and erosion;and implications on plant operation and associated costs. The article will detail a comprehensive understanding on sustainable biomass supply, co-firing ratios and how direct biomass co-combustion under oxy-fuel conditions can be implemented. It seeks to push biomass co-combustion in future large-scale oxy-fuel CFB power stations to high thermal shares while enhancing the power plants’ operational flexibility, economic competitiveness and give operational procedures. There will be a need to consider the public acceptance of power production from coal and coal sustainability, by its combination with renewable sources of energy (biomass).

小型燃气锅炉掺烧生物质气的模拟

采用Fluent软件,模拟小型燃气锅炉掺烧生物质气对锅炉燃烧工况的影响。通过控制燃气锅炉在不同负荷下掺烧生物质气体量的百分比,分析燃烧室内火焰偏移量,烟气流动均匀程度,以及对火焰的冲击情况。同时,在保证燃烧稳定的条件下,确定科学合理的生物质气和天然气的最佳掺烧比例。模拟结果表明:一次换热管内烟气速度略有提高,速度差异降低;二次换热管出口烟气速度差异也有所下降;出口烟气温度明显下降,整体换热效果有所提高。

Optimization Study of Active-Passive Heating System Parameters in Village Houses in the Southern Xinjiang Province

Aiming at the problems of large energy consumption and serious pollution of winter heating existing in the rural buildings in Southern Xinjiang,a combined active-passive heating system was proposed,and the simulation software was used to optimize the parameters of the system,according to the parameters obtained from the optimization,a test platform was built and winter heating test was carried out.The simulation results showed that the thickness of the air layer of 75 mm,the total area of the vent holes of 0.24 m^(2),and the thickness of the insulation layer of 120 mm were the optimal construction for the passive part;solar collector area of 28 m^(2),hot water storage tank volume of 1.4 m^(3),mass flow rate of 800 kg/h on the collector side,mass flow rate of 400 kg/h on the heat exchanger side,and output power of auxiliary heat source of 5∼9 kWwere the optimal constructions for active heating system.Test results showed that during the heating period,the system could provide sufficient heat to the room under different heating modes,and the indoor temperature reached over 18°C,which met the heating demand.The economic and environmental benefits of the system were analyzed,and the economic benefits of the systemwere better than coal-fired heating,and the CO_(2) emissionswere reduced by 3,292.25 kg compared with coalfiredheating.The results of the study showed that the combinedactive-passiveheating systemcouldeffectively solve the heating problems existing in rural buildings in Southern Xinjiang,and it also laid the theoretical foundation for the popularization of the combined heating systems.

基于LSTM-SAFCN模型的生物质锅炉NO_(x)排放浓度预测

针对生物质锅炉燃烧过程的动态特性,提出一种改进的长短期记忆-自注意力机制全卷积神经网络(LSTM-SAFCN)模型用于预测NO_(x)排放浓度。首先利用完全自适应噪声集合经验模态分解法(CEEMDAN)对数据进行预处理,消除数据噪声对NO_(x)排放浓度预测的影响;其次融合自注意力机制与长短时记忆-全卷积神经网络(LSTM-FCN)进行特征提取与预测建模,该拓展方法能够同时兼顾时间序列数据的局部细节与长期趋势特征;最后,利用生物质热电联产系统的实际运行数据验证了所提算法的有效性。

空气源热泵生物质锅炉联合供热系统应用性能模拟

为研究我国北方农村地区利用可再生能源生物质能与空气源热泵相结合的供热系统的实际应用性能,以沈阳市农村某小区建筑为案例,采用TRNSYS动态系统搭建空气源热泵与生物质锅炉联合供热系统仿真模型进行模拟研究。该系统通过时间模块调控采取两种控制策略,与单一的空气源热泵供热系统进行对比,并对这3种模式的系统运行特性进行分析比较。联合供热系统模式1整个采暖季平均耗电量较单一空气源热泵供热系统降低56%;平均制热性能系数提高0.19;可再生能源利用率和一次能源利用率分别增幅25.21%和63%,当供水温度45℃、生物质锅炉供热占比60%时总投资费用相对较低,空气源热泵与生物质锅炉联合供热系统运行更高效节能。

基于一次风精细配风的生物质炉排炉燃烧数值模拟

生物质炉排炉内一次风沿炉排长度方向的配风方式会显著影响其燃烧特性,但目前未见相关报道。该文以某130t/h的秸秆直燃炉排炉为研究对象,探究一次风配风方式对炉内燃烧和污染物生成等关键参数的影响。开展一次风均匀(基准)、分段和精细分段配风下,炉排和炉膛气固两相燃烧的耦合数值模拟。结果表明:1)基准工况的模拟值与现场实测的炉内温度和出口NO等相对误差均在10%以内;2)与均匀配风相比,分段和精细分段配风提高了挥发分和焦炭燃烧段的氧气含量,促使更多的可燃物在固相燃烧,焦炭燃尽率由76.5%升至87.8%和95.5%;相应的从床层逸出到气相的可燃气体减少,使炉膛内烟气温度峰值降低且分布更加均匀;3)后两个工况中避免了炉内出现局部高温、富氧区域,NOx的形成受到抑制,出口NO由172mg/m^(3)(11%O_(2))降至161mg/m^(3)和156mg/m^(3)。综上,沿炉排长度进行一次风的分段或精细分段配风,可明显改善生物质的燃尽和污染物生成特性。

融合激光雷达料位测算的锅炉燃烧优化模型预测控制

提出了一种融合激光雷达料位测算的锅炉燃烧优化控制策略。该控制策略通过激光雷达对生物质的入炉给料量进行实时在线监测,并采用最大互信息系数(MIC)方法分析其对于主汽压力、燃烧室温度、出口烟气氧量等关键参数的时延长度,结合经过特征筛选的锅炉特征参数,构成模型样本集;通过粒子群优化(PSO)算法进行参数优化,获得燃烧过程外源自回归(ARX)模型,并采用模型预测控制的方法优化锅炉燃烧。以700t/d生物质燃烧发电锅炉为测试对象,该控制策略在主汽压力与燃烧室温度约束下实现了烟气氧量优化。实验结果与对比分析表明:(1)该预测模型具有较高的精度与泛用性,能满足预测控制的要求;(2)相较于PID与模糊控制,该控制算法拥有更高的控制性能,在仿真结果中氧量与其设定值的平均偏移能控制在±25%以内。该控制策略理论上具有较好的实践意义,可为生物质发电锅炉的智能化稳定燃烧提供解决方案。

660MW燃煤锅炉掺烧生物质颗粒数值模拟研究

随着“双碳”目标的提出,生物质作为一种绿色零碳的清洁燃料,将迎来历史性的发展机遇。本文通过数值模拟手段研究稻壳、秸秆、木屑三种不同生物质颗粒以不同的粒径和煤粉掺烧,对比分析了不同生物质颗粒和煤粉掺烧时炉膛内生物质颗粒轨迹、停留时间和燃尽率的变化趋势。结果显示:生物质颗粒以10%热量比和煤掺烧,生物质颗粒在炉内有足够的停留时间保证燃尽,整体生物质颗粒燃尽程度较好,并从数值模拟结果中选取4种掺烧生物质工况用于指导设计。

生物质直燃锅炉水冷管腐蚀与防护探析

生物质直燃锅炉是新型能源利用的重要设备,在能源结构调整和社会经济可持续发展中作用重大。文中分析了生物质燃料的燃烧过程,针对生物质锅炉基本结构特点,论述了生物质锅炉的腐蚀机理。从常规防腐技术和表面改性防腐技术两个方面探究了腐蚀防护方法,通过对比分析得到:采用表面改性防腐技术,在锅炉易腐蚀件表面制备纳米复合涂层,能够有效解决生物质直燃锅炉的腐蚀问题。

低负荷下生物质掺烧比例对循环流化床锅炉燃烧性能的影响

为了研究生物质在低负荷下循环流化床机组深度调峰中的应用潜力,本文结合实验和数值模拟方法,分析不同生物质掺混比例对CFB锅炉内部温度、压力、气体浓度及颗粒动态的影响。研究发现,生物质掺混比为10%、20%时,循环流化床密相区升温速率提高2~8℃/min,但稳定温度随掺混比增加而降低。为深入了解造成这种现象的原因,分别对3种工况进行数值计算后发现:掺烧比由0%提升至20%时,密相区压降由900 Pa减少至700 Pa;CO浓度由10%降低至5%;CO_(2)浓度从17%降低至12%;颗粒浓度降低了18%。相对地,稀相区各组分浓度出现增加,特别是颗粒浓度增加了达38%。表明生物质的掺入促使燃烧区域向炉膛中上部移动。这一发现证明了生物质掺烧能有效提高低负荷下炉内升温特性且满足“双碳”目标下的需求,为低负荷下电网调峰提供了新方法。

300 MW循环流化床锅炉燃煤耦合生物质燃烧及污染物排放特性试验研究

在碳达峰、碳中和背景下,发展燃煤与生物质耦合发电是加快电力转型升级、实现煤电低碳发展的重要途径之一。在某台300 MW循环流化床(CFB)锅炉上设计建设了一套燃煤直燃耦合生物质的燃烧发电系统,并利用该系统进行了燃煤直燃耦合生物质的燃烧特性试验研究。结果表明:该生物质直燃耦合系统运行稳定可靠;CFB锅炉在掺烧木屑颗粒燃料时,随着掺烧比的增加,混合燃料的飞灰含碳量下降、CO排放量降低,混合燃料的燃尽性得以改善;掺烧后经过锅炉燃烧配风优化,锅炉NOx排放量比纯烧原煤排放量略有降低。试验典型工况污染物测试表明:掺入木屑颗粒燃料后,锅炉烟气二噁英排放量为0.0088 ng TEQ/m^(3)(标准工况,φ(O_(2))=11%,下同),飞灰中二噁英排放量为0.0206 ng TEQ/m^(3);飞灰中重金属及P、As、Se等有害微量元素排放值总量为32.121mg/L;底渣中重金属及P、As、Se等有害微量元素排放值总量为3.918 mg/L,烟气和飞灰中的二噁英和重金属等有害物质排放均满足国家环保标准排放限值。

燃煤锅炉改造为生物质锅炉应用案例

近几年来,国家重点推行可再生能源的政策,各地市陆续淘汰落后燃煤锅炉,国家的环保政策对燃煤锅炉越来越严格。为了适应国家政策的发展和企业发展需求,生物质燃料和生物质锅炉越来越受人们关注和研究。本文就循环流化床燃煤锅炉改造为生物质锅炉应用案例进行阐述,剖析了改造技术方案,从生产实践角度对比了改造后运行和效益情况。

废固焚烧系统表面积灰的影响与防治技术研究

在固废再利用领域,焚烧发电是一种常见的再利用方式,但固废焚烧的积灰会对锅炉产生危害。因此为了探讨积灰对锅炉的影响,研究搭建了固废焚烧锅炉腐蚀模拟系统,并分析了灰渣和腐蚀产物的成分。实验结果显示,木片和菌类的氯元素质量分数分别为0.58%和0.35%,均高于0.3%;且木片和模板的酸碱比分别为2.25和1.96,均大于1.75。可见,生物质燃料的飞灰具有腐蚀作用和结渣倾向。锅炉积灰的包括氯化钾、氯化钠、硫酸钙和钾芒硝等,且其中硫元素含量大于生物质燃料。锅炉腐蚀产物主要由氧化铁、四氧化三铁、硫酸钾和铁构成,且由于锅炉中的高温环境,导致燃烧产生的二氧化硫发生氧化反应,生成了碱金属硫酸盐。上述结果表明,研究提出的方法能准确模拟固废焚烧的情况及积灰对锅炉的影响,为锅炉腐蚀及烟道堵塞防治措施的制定提供了有力参考。