I MWth Test Facilities for Circulating Fluidized Bed Combustion

This paper presents the technical parameters and features of 1 MWth test facilities for circulating fluidized bed combustion (CFBC) at Thermal Power Research Institute (TPRI) of State Power Corporation (SP), introduces the test items that can be proceeded and trial combustion projects completed. The development status of CFBC technologies abroad and the level of China in this field are also introduced in the paper.

Highly efficient CO_(2) capture using 2-methylimidazole aqueous solution on laboratory and pilot-scale

To date,the primary industrial carbon capture approach is still absorption using aqueous solutions of alkanolamines.Here,to pursue a substitute for the amine-based approach to improve the CO_(2) capture efficiency and decrease the energy cost further,we report a new carbon capture approach using a 2-methylimidazole(mIm)aqueous solution.The properties and sorption behaviors of this approach have been experimentally investigated.The results show that the mIm solution has higher CO_(2) absorption capacity under relatively higher equilibrium pressure(>130 kPa)and lower desorption heat than the methyldiethanolamine solution.91.6%sorption capacity of mIm solution can be recovered at 353.15 K and 80 kPa.The selectivity for CO_(2)/N_(2) and CO_(2)/CH_(4) can reach an exceptional 7609 and 4324,respectively.Furthermore,the pilot-scale tests were also performed,and the results demonstrate that more than 98%of CO_(2) in the feed gas could be removed and cyclic absorption capacity can reach 1 mol·L^(-1).This work indicates that mIm is an excellent alternative to alkanolamines for carbon capture in the industry.

Experimental Tests on a Pre-Heated Combustion Chamber for Ultra Micro Gas Turbine Device: Air/Fuel Ratio Evaluation

Current portable power generators are mainly based on internal combustion engine since they present higher values of efficiency comparing to other engines;the main reason why internal combustion engine is not convenient for micro power generation (5 - 30 kW) is because of their heaviness. Micro and ultra micro gas turbine devices, based on a micro compressor and a micro turbine installed on the same shaft, are more suitable for this scope for several reasons. Micro turbine systems have many advantages over reciprocating engine generators, such as higher power density (with respect to size and weight), extremely low emissions and few, or just one, moving part. Those designed with foil bearings and air-cooling operate without oil, coolants or other hazardous materials. Micro turbines also have the advantage of having the majority of their waste heat contained in their relatively high temperature exhaust. Micro turbines offer several potential advantages compared to other technologies for small-scale power generation, including: a small number of moving parts, compact size, lightweight, greater efficiency, lower emissions, lower electricity costs, and opportunities to utilize waste fuels. The object of this study is the experimental tests on a stand-alone gas turbine device with a pre-heated combustion chamber (CC), to validate the fuel consumption reduction, compared to an actual and commercial device, used on air models.

DAMAGE OF A HIGH-ENERGY SOLID PROPELLANT AND ITS EFFECTS ON COMBUSTION

In order to improve the safety of high-energy solid propellants, a study is carried out for the effects of damage on the combustion of the NEPE (Nitrate Ester Plasticized Polyether) propellant. The study includes: (1) to introduce damage into the propellants by means of a large-scale drop-weight apparatus; (2) to observe microstructural variations of the propellant with a scanning electron microscope (SEM) and then to characterize the damage with density measurements; (3) to investigate thermal decomposition; (4) to carry out closed-bomb tests. The NEPE propellant can be considered as a viscoelastic material. The matrices of damaged samples axe severely degraded, but the particles are not. The results of the thermal decomposition and closed-bomb tests show that the microstructural damage in the propellant affects its decomposition and burn rate.

Study on the Treatment of Acid Mine Drainage Containing Fe^(2+) and Mn^(2+) Using Modified Spontaneous Combustion Gangue

The high concentrations of Fe^(2+) and Mn^(2+) in acid mine drainage make it difficult and expensive to treat.It is urgent that we find a cheap and efficient adsorption material to treat Fe^(2+) and Mn^(2+).As a solid waste in mining areas,coal gangue occupies a large area and pollutes the surrounding environment during the stacking process.Developing a method of resource utilization is thus a research hotspot.In this study,we modified spontaneous combustion gangue using NaOH,NaCl,and HCl by chemically modifying the minerals.We determined the optimal conditions for treating Fe^(2+) and Mn^(2+) in acid mine drainage with spontaneous combustion gangue and modified coal gangue using the single factor test method.Based on results of the static test,two dynamic test columns,column No.1(spontaneous combustion gangue)and column No.2(NaOH modified spontaneous combustion gangue),were constructed,and the repair effects of acid mine drainage were compared and analyzed using dynamic experiments.The results show that overall,NaOH modified spontaneous combustion gangue is the most efficient at removing the Fe^(2+) and Mn^(2+) in acid mine drainage.The optimal conditions for NaOH modification are an NaOH concentration of 3 mol/L,a liquid to solid ratio of 2 L/kg,and a modification time of 8 h.The overall efficiency of column No.2 at removing Fe^(2+) and Mn^(2+) from acid mine drainage is better than that of column No.1.Among them,the average removal efficiency of Fe^(2+)and Mn^(2+) from acid mine drainage in column No.2 were 97.73%and 44.82%,respectively.The above results show that NaOH modified spontaneous combustion gangue is a good adsorbent,which has application potential in wastewater remediation,as it can achieve the purpose of“treating dust with waste”.

Combustion Synthesis of C/MgAl_(2)O_(4)Composite Powders and Their Microstructure Evolution

This work aims at solving the problems of difficult dispersion,easy oxidation and high cost of nano carbon during application,carbon/magnesium aluminate spinel(C/MgAl_(2)O_(4))composite powders were prepared using MgC2O4·2H2O,MgO2,Al2O3 powder,and Al powder as raw materials by combustion synthesis.The results indicate that with the maximum MgC2O4·2H2O addition of 33.34 mass%,the prepared powder contains 1.17 mass%of carbon and carbon distributes among spinel grains.The MgAl_(2)O_(4)spinel shows both granular and rod-like morphologies.The granular MgAl_(2)O_(4)spinel is generated from mutual diffusion between MgO and Al2O3;while the rod-like MgAl_(2)O_(4)spinel is mainly formed by the vapor-solid growth mechanism from Mg vapor and Al2O3.

Evaluation on Combustion Characteristics of Finishing Materials for Exterior Walls

Existing fire test methods reply on measurement of the energy released rate to identify the combustion properties of a material. However, they are inadequate when assessing combustion characteristics of a composite material characterized by vertical flame spread and different inside/outside combustion behaviors. In addition, major factors that affect the flame spread outside the building include the combustion characteristics of materials used as well as air flow around a skyscraper. However, since it is highly difficult to analyze and forecast the air flow from a fire engineering viewpoint, an investigation of the flame spread characteristics of exterior walls of a building depends primarily on the combustion characteristics of materials. Hence, this study examined, using ISO 13785-2 testing method, the temperature changes and vertical flame spread behaviors of one of the finishing materials for exterior walls--（generic ＆ fire-resistant） aluminium panels by a real-scale combustion experiment. According to the results of real-scale experiment, the maximum heat temperature of 987.7 ℃ was recorded seven minutes after the fire test was initiated while the fire-resistant aluminium panels showed the maximum heat temperature of 850.2℃ after exposed for approximately 12 min. The vertical flame spread properties put more emphasis on the time required to reach the maximum temperature rather than its magnitude and there was a five minutes difference between the materials.

Influence of multiple structural parameters on interior ballistics based on orthogonal test methods

Influence of multiple structural parameters on the performance of a gun launch system driven by highpressure reactive gases is important for structural design and performance adjustment.A coupled lumped parameter model was utilized to predict the propellant combustion,and a dynamic finite element method was applied to approximate the mechanical interactions between the projectile and the barrel.The combustion and the mechanical interactions were coupled through a user subroutine interface in ABAQUS.The correctness and the capability of the finite element approximations in capturing small structural changes were validated by comparing predicted resistance with experiments.Based on the coupled model,the influence of structural parameters of a medium-caliber gun on the system performance was investigated.In order to reduce the research costs,orthogonal tests were designed to investigate the comprehensive effects of the parameters.According to statistical analysis,the important order of the structural parameters on the launching process was obtained.The results indicate that the influence of the width of the rotating band stands out among the studied parameters in the gun.The work provides a method to investigate the influence of multiple parameters on system performance and gives guidance for controlling the system performance.

Reaction mechanism of arsenic capture by a calcium-based sorbent during the combustion of arsenic-contaminated biomass: A pilot-scale experience

Large quantities of contaminated biomass due to phytoremediation were disposed through combustion in low-income rural regions of China.This process provided a solution to reduce waste volume and disposal cost.Pilot-scale combustion trials were conducted for in site disposal at phytoremediation sites.The reaction mechanism of arsenic capture during pilot-scale combustion should be determined to control the arsenic emission in flue gas.This study investigated three Pteris vittata L.biomass with a disposal capacity of 600 kg/d and different arsenic concentrations from three sites in China.The arsenic concentration in flue gas was greater than that of the national standard in the trial with no emission control,and the arsenic concentration in biomass was 486 mg/kg.CaO addition notably reduced arsenic emission in flue gas,and absorption was efficient when CaO was mixed with biomass at 10% of the total weight.For the trial with 10% CaO addition,arsenic recovery from ash reached 76%,which is an ~8-fold increase compared with the control.Synchrotron radiation analysis confirmed that calcium arsenate is the dominant reaction product.

A comparative study of combustible cartridge case materials

Foamed combustible material based on polymer bonded RDX was fabricated using CO_2 as foaming agent.The inner structures of felted and foamed combustible materials were presented by SEM. The two materials presented different formulations and inner porous structures. The combustion behaviors of felted and foamed materials were investigated by closed vessel test. Simultaneously, the co-combustion behavior of combustible cartridge case with 7-perf consolidated propellants was also investigated. The results of closed vessel test is applicable to gun system which is made of the foamed combustible material as component.

Burning characteristics of microcellular combustible objects

Microcellular combustible objects for application of combustible case,caseless ammunition or combustible detonator-holding tubes are fabricated through one-step foaming process,in which supercritical CO_2 is used as foaming agent.The formulations consist of inert polymer binder and ultra fine RDX.For the inner porous structures of microcellular combustible objects,the cell sizes present a unimodal or bimodal distribution by adjusting the foaming conditions.Closed bomb test is to investigate the influence of both porous structure style and RDX content on burning behavior.The sample with bimodal distribution of cell sizes burns faster than that with unimodal distribution,and the concentration of RDX can influence the burning characteristics in a positive manner.In addition,the translation of laminar burning to convective burning is determined by burning rate versus pressure curves of samples at two different loading densities,and the resulting transition pressure is 30 MPa.Moreover,the samples with bigger sample size present higher burning rate,resulting in providing deeper convective depth.Dynamic vivacity of samples is also studied.The results show that the vivacity increases with RDX content and varies with inner structure.

喷淋作用下的深水测试放喷热辐射规律及关键参数

在深水天然气测试过程中,多相混合物会通过地面流程分离、泄压、加热后通过燃烧臂放喷燃烧,现场一般采用喷淋的方式来降低热辐射的影响。为了降低深水放喷测试作业时平台及燃烧臂的热辐射风险隐患,首先采用Thornton模型研究了火焰表面辐射能量、视角系数以及水幕透射率等参数,构建了喷淋作用下放喷火焰的热辐射通量计算模型,并结合现场燃烧放喷下的仿真模型,应用有限元软件分析了放喷喷淋影响下的火焰温度和辐射量变化规律。研究结果表明:(1)喷淋形成的水幕使靠近平台区域的温度和辐射量明显降低,放喷管道附近的辐射量由2 050 W/m^(2)减小到了1 840 W/m^(2);(2)在单个水幕的作用下,水幕吸收了一定的热辐射量,水幕温度从11.85℃上升到约26.85℃;(3)由于平台附近的空气中CO_(2)和H_(2)O含量较低,空气的热辐射吸收系数较小,温度主要受到热对流的影响,空气温度基本保持在26.85~36.15℃之间;(4)不同放喷管径和产量变化下平台附近区域的温度和辐射量变化趋势基本一致,管径减小使得辐射峰值增大。结论认为,该研究成果进一步明确了深水测试放喷不同工况下的热辐射分布,为深水地面放喷热辐射设计分析及安全控制提供了技术支撑。

飞机火焰抑制器阻火测试中混合气体的适用性研究

文章对典型民用飞机油箱通气口飞机火焰抑制器火焰传播特性开展试验研究。根据SAEARP5416中规定的H_(2)、O_(2)、Ar3种混合气体的燃爆方案,借鉴ISO16852标准下的试验方法,自建燃爆试验台,并分别在不同H_(2)体积分数、阻火芯体内部孔径和芯体长度的情况下开展系列试验,并与现行商用阻火器特性进行对比,同时使用高速摄像机获得爆燃阻火现象及规律并开展仿真对比。试验结果表明,使用体积分数为5.0%~10.0%的H_(2)进行飞机火焰抑制器火焰传播试验时,试验阻火成功率极低,并得到H_(2)体积分数升高对火焰传播速度的影响规律。研究表明,H_(2)与航空煤油蒸气的特性差异是阻火失效的关键因素。该文对此次试验的混合气体局限性进行分析,试验结果也为H2类阻火器的研究提供一定的参考。

振荡提取-氧弹燃烧-离子色谱法测定纺织品中的可吸附有机卤化物

采用振荡提取、氧弹燃烧以及离子色谱定量检测等步骤测定纺织品中可吸附有机卤化物(AOX)。将纺织品加入到适量的提取液中,通过振荡使AOX充分溶解并富集在活性炭上,使用酸性硝酸钠溶液处理以去除无机卤化物。采用氧弹燃烧方式对可吸附AOX的活性炭进行裂解、燃烧及气化,采用离子色谱法测定。结果发现,在标准溶液0.02~2.50mg/L范围内,Cl^(-)、Br^(-)和I^(-)的线性相关系数R2在0.999以上,AOX的定量限为7.58~8.67mg/L,在不同的加标水平下AOX的平均回收率在83.1%~98.1%,相对标准偏差RSD(n=7)为2.1%~5.9%,表明方法具有良好的回收率和精密度。

高燃压中型运载火箭发射地面低高度排导技术

综合高燃压中型运载火箭高密度发射燃气流地面排导需求及烧蚀风险分析,提出基于地面双面导流装置与高位挡流墙结合的地面低高度排导技术方案。利用火箭发射燃气动力学研究总结的燃气流膨胀特性以及导流型面设计方法,解决了地面低高度排导技术涉及的地面导流装置导流型面气动设计以及尺度控制两个关键问题。地面低高度排导技术方案设计与燃气流场瞬态仿真多轮叠代,实现了燃气流排导烧蚀范围合理控制,避免了燃气流低高度排导烧蚀反溅影响箭体。地面低高度排导技术采用专利支撑的喷水冷却防护方案实现高燃压中型运载火箭发射燃气流强烧蚀环境发射系统、发射设施综合防护。基于喷流缩比试验相似性控制方法研制了1∶10比例喷流缩比试验系统,通过喷流缩比试验验证确认高燃压中型运载火箭发射燃气流能够实现地面低高度安全、顺畅排导,同时与发射台、导流装置结构融合的阵列喷水方案能够行之有效解决高燃压中型运载火箭地面低高度排导强烧蚀难题。

煤粉火焰着火燃烧特性与光学诊断测试

经过上百年的煤燃烧研究为煤炭的工业应用奠定了坚实的基础,但是煤燃烧的内部稳定性、着火的机制的转变以及污染物的生成依然没有明确的理论指导,光学测量技术的发展为研究燃烧机理提供了合适可靠的工具,燃烧诊断在全球的学术界研究成为热点。本文综述了煤粉燃烧的激光诊断研究特性:着火、燃烧稳定性、挥发分燃烧等,并分析国内外的研究现状。

大流量高压燃烧加热器振动加速度测试分析

针对不同采样频率下(10、20、50、100、200 kHz)大流量高压燃烧加热器振动加速度差异较大的问题进行了研究,开展了冷吹试验、敲击试验、点火试验。采用时域分析法中的均方根、偏度、峭度,频域分析法中的功率谱密度,时频域分析法中的小波变换,并结合模态参数识别中的多参考最小二乘复频域法重点分析了10 kHz和200 kHz采样频率下的振动数据。获得了传感器的安装谐振频率、安装底座和待测设备组合体的固有频率以及加热器运行的主要频段,与声振频率计算公式的结果偏差小于5%。研究结果表明,采用10 kHz的采样频率能够有效表征加热器的振动情况,该方法可为大型复杂燃烧设备振动测试采样频率的选择提供参考。

基于FPGA和LoRa的燃烧室振动信号无线测试装置设计

燃烧不稳定性问题可引起大幅的机械振动,严重影响发动机正常工作。为满足新型试验需求,针对传统燃烧室测试装置灵活性不足、可靠性差等问题,设计了一种基于FPGA和LoRa的燃烧室振动信号无线测试装置,以FPGA作为主控单元,将前端高速AD采集的振动传感器数据存入Flash,通过LoRa技术并结合以太网的高速运行,在PC端进行远程操控和数据处理。试验表明:该装置可以实现至少500 m开阔距离内待测燃烧室振动信号的可靠测试,工作稳定,实时性强。

深水测试地面流程放喷热辐射安全

为了对深水地面放喷火焰的温度与辐射量进行研究,从而预测放喷过程中的安全范围。基于此建立喷射火焰的热辐射强度理论计算模型,并采用有限元分析软件模拟喷射火焰的热辐射分布规律。根据深水测试现场实际放喷管汇,研究臂长为25 m时,不同管径和不同放喷产量对喷射火焰热辐射分布规律的影响。研究结果表明:①放喷火焰呈纺锤形分布,火焰中心的温度与辐射量最大,随着距离增加,温度和辐射量逐渐减小;②相同放喷产量下,随着放喷管径增大,100 kW/m^(2)以上的辐射区域轴向和径向范围尺寸逐渐增大,且最高辐射量也逐渐增大;③相同放喷管径下,随着产量的增加,温度和辐射量整体上都有一定程度的增加。④总体温度与辐射量在趋势上呈先上升,达到峰值后再下降,后又有小幅度上升。相关研究结果为深水测试地面放喷安全评价提供了一定理论支撑。

基于煤粉预气化强稳燃的快速调峰燃烧器5 MW中试研究

煤粉预气化强稳燃技术能够兼顾稳定燃烧与NO_(x)排放控制。基于此,开发了服务于电站锅炉灵活调峰的快速调峰燃烧器,并依托5 MW燃烧试验平台进行热态中试试验,对比不同负荷下的运行性能,研究燃烧器的极限稳燃负荷与快速变负荷能力。结果表明:煤粉进入燃烧器所带有的小型预气化室后发生气化反应,转化为高温燃气和炽热碳粒所组成的预热燃料。在低负荷下,预热燃料进入炉膛后将迅速燃烧,形成根部高温区,保证炉膛稳燃。随着负荷升高,预气化室内气化反应更加充分,配合回流烟气形成良好还原性气氛,实现有效降氮。在无辅助手段条件下,满负荷工况NO_(x)排放为159 mg/m^(3)(6%O_(2)),飞灰含碳率为3.4%,折算燃烧效率99.71%。在9%超低负荷下,快速调峰燃烧器仍能维持炉膛稳定燃烧,在1 h以上长时间连续运行过程中,出口氧量保持稳定。在15%~100%负荷分别用时8和9 min完成快速降负荷与升负荷过程,降、升负荷速率分别可达10.63%/min与9.44%/min。变负荷过程中炉内燃烧保持稳定,且温度分布对负荷变化的响应速度较快,验证了该燃烧器在快速调峰过程中的出色性能。