基于锥形量热仪实验研究阻化剂对煤自燃的影响

利用锥形量热仪多角度实验模拟研究阻化剂对煤升温氧化的影响,在实验过程中运用锥形量热仪对添加两种阻化剂的煤样自燃特性进行分析,考察了添加原有煤样和氯化镁、防老剂两种常用阻化剂后的点燃时间、热释放速率,CO产生率对煤自燃特性的影响。结果表明:MgCl2阻化煤样的引燃时间最长为369s,热释放速率最小;MgCl2阻化煤样的CO产率在燃烧中期很大,防老剂阻化煤样的CO产率在后期较大;MgCl2阻化煤样的比消光面积最小,防老剂阻化煤样的比消光面积在前期较大,在后期逐渐减小。研究表明:同一阻化煤样对于不同的实验参数其影响不完全一致;MgCl2对煤样的阻化效果最好,防老剂在后期有较好的阻化效果。     

外部热辐射对材料燃烧性能影响的实验研究

采用基于耗氧量原理的锥形量热计对木材、PVC以及聚氨酯泡沫塑料在不同热辐射条件下的热释放速率、平均释热速率、点燃时间、CO／C02生成率和烟气的减光性等燃烧特性进行了研究。实验结果表明，不同材料表现出不同的点燃性、热释放速率及烟气生成特征，并进行了初步的理论探讨。     

基于锥形量热仪测试的树叶燃烧碳排放研究

运用锥形量热仪模拟开放环境中植物样品在不同火灾场合的燃烧场景,检测其燃烧过程中CO和CO_2排放量,进而确定其碳转化率和排放比.实验样品为针阔叶树种叶片共8种;辐射热流强度分别为35,k W/m2、55,k W/m2、70,k W/m2和85,k W/m2.测试结果表明,在设定的装载量范围内,样品碳转化率基本不受空间分布密度的影响,并呈现较好的数据可重复性,由此确认了检测方法的可靠性.因辐射热流强度和样品含水量的差异,树叶样品的CO和CO_2的转化率范围分别为0.01~0.10和0.05~0.85,且随着辐射热流强度增大而显著提升;新鲜样品含水量的降低促使其由阴燃向明火转变,明火燃烧则会促进CO和CO_2的生成,这与开放环境中样品热解产物燃烧反应的效率以及碳烟形成有关.     

木粉含量对木粉/PP复合材料的热性能与燃烧性能的影响

利用热重分析法(TGA)和锥形量热仪(CONE)研究了不同木粉含量对木塑复合材料(WPC)热稳定性和燃烧性能的影响.TGA研究结果表明,随着木粉含量的增加,WPC的热稳定性逐渐降低,但体系的成炭量明显提高,800℃时成炭率由0.01％增加到14.63％;锥形量热仪(CONE)的实验结果表明,WPC的热释放速率、比消光面...     

用锥形量热仪研究胶合板的燃烧特性

采用符合ISO5660标准的锥形量热仪研究典型胶合板的燃烧性能．实验中选用4种不同类型的胶合板,其样品材料的厚度分别是3 mm、5 mm、9 mm和12 mm,外加热辐射通量是25 kW／m2、50 kW／m2和75 kW／m2,研究胶合板的密度、厚度和热辐射对材料的点燃时间、热释放速率、质量损失速率的影响．通过对实验数据的分析比较,提出了预测以上这些参数的经验公式,并通过实验验证了其可靠性．     

油罐火灾燃烧速度的实验研究

燃烧速度是油罐火灾中决定火焰温度和辐射热的重要参量,其变化规律也决定着火灾中灭火预案及战术的制定．通过对直径为1．0m、1．5m和2．7m的汽油和柴油储罐火灾的燃烧实验,获得了油品的瞬时燃烧速度和平均燃烧速度的变化规律．研究得出,油品的种类和油罐直径对平均燃烧速度影响较大,另外随着油初温的升高、风速的加大以及升高油位,都会增大油品的燃烧速度．在此基础上,拟合了相应条件下的实验关联式,并简要分析了各种影响因素的燃烧学机理．     

混煤燃烧特性的实验研究

选择武钢高炉混煤喷吹的某种烟煤和某种无烟煤为研究的煤源,对不同混合比例的混煤燃烧进行了实验研究。利用差热天平的TG—DTG—DTA热分析,探讨了烟煤不同掺混比对混煤的燃烧特性的影响规律和合适的烟煤掺混比例,阐明了烟煤掺混高炉喷煤技术经济指标的改善作用。     

火灾中木耳燃烧特性及数值模拟

从基础研究角度出发,针对湖南衡阳“11．3”特大火灾事故的重要可燃物木耳,应用符合ISO 9705标准的ISO ROOM装置对其进行全尺寸实验研究,并测量包括热释放速率、质量损失速率、房间内温度场、组分浓度等多个参量．同时对该过程进行了计算机数值模拟,计算结果与实验数据具有较好的一致性,为下一步对衡阳“11．3”整个火灾场景进行数值模拟研究提供了基础．     

CuO对木粉/PVC复合材料热解和燃烧过程中烟释放行为的影响

采用热重分析法、锥形量热仪测试及Py-GC-MS联机方式研究了CuO对木粉/PVC复合材料(WF-PVC)热解和燃烧过程烟释放行为的影响.实验结果表明,WF-PVC热解过程具有PVC热解的特性;与WF-PVC相比,用CuO处理WF-PVC能明显提高第1阶段质量损失,降低第2阶段的质量损失,提高成炭量;WF-PVC燃烧过程中烟释放速率和总烟量低于PVC,用CuO处理WF-PVC总烟量降低更显著;Py-GC-MS分析结果表明,与PVC相比,WF-PVC以及用CuO处理的WF-PVC,燃烧气相组分中芳香族化合物含量分别降低52.29%和49.34%;加入CuO,抑制了气相组分中多环化合物的生成.     

固定床玉米秸燃烧特性的实验研究

影响生物质燃烧特性的因素主要包括燃料长度、空气预热温度、送风量和燃料含水量。研究了上述因素对玉米秸的燃烧特性，包括指燃料失重率、炉内温度以及炉内的气体成分的影响，并对影响的机理进行了相应的分析。     

Optimization of pyrolysis properties using TGA and cone calorimeter test

The present paper describes an optimization work to obtain the properties related to a pyrolysis process in the solid material such as density, specific heat, conductivity of virgin and char, heat of pyrolysis and kinetic parameters used for deciding pyrolysis rate. A repulsive particle swarm optimization algorithm is used to obtain the pyrolysis-related properties. In the previous study all properties obtained only using a cone calorimeter but in this paper both the cone calorimeter and thermo gravimetric analysis (TGA) are used for precisely optimizing the pyrolysis properties. In the TGA test a very small mass is heated up and conduction and heat capacity in the specimen is negligible so kinetic parameters can first be optimized. Other pyrolysis-related properties such as virgin/char specific heat and conductivity and char density are also optimized in the cone calorimeter test with the already decided parameters in the TGA test.     

Modelling the pyrolysis of wet wood – II. Three-dimensional cone calorimeter simulation

Application of a three-dimensional mathematical model for the pyrolysis of wet wood coupled with the gas phase combustion to the analysis of a wood sample ignited in a cone calorimeter is described. Time-dependent chemical and physical processes of wet wood model described in Part I is employed with transient gas phase flow described by Navier–Stokes equations. Predicted ignition times compared well against experimental data for cone irradiation fluxes of 20–70 kW m⁻² with initial moisture contents of 0%, 5% and 10%. This study further demonstrates the feasibility of application of the developed wet wood model in fire-engineering.     

Experimental and numerical study of the effects of nanoparticles on pyrolysis of a polyamide 6 (PA6) nanocomposite in the cone calorimeter

A large number of studies using the cone calorimeter showed that nanoparticles used even in small quantities (e.g. 3 wt.%) improve fire retardancy by reducing significantly the heat release rate/mass loss rate. The improved fire retardancy by nanocomposites has been attributed usually to the formation of a surface layer as a result of accumulation of nanoparticles on top of the virgin polymer because this surface layer not only acts as mass and thermal barriers to the polymer underneath but primarily increases surface radiation losses as the surface temperature increases. Various theories have been proposed for qualitatively explaining the mechanism of nanoparticles action, including mainly (a) gasification of polymer and precipitation of nanoparticles, (b) migration of nanoparticles towards the surface and (c) nanoconfinement. However, quantitative investigation on the effects of nanoparticles on pyrolysis has never been undertaken. In this work, square samples of a polyamide 6 (PA6) nanocomposite were tested in the cone calorimeter under different heat fluxes. By combining the experimental mass loss data and numerical calculations, a novel approach is developed to quantify the effects of nanoparticles and subsequently to predict pyrolysis of the PA6 nanocomposite at different heat fluxes and thicknesses, in good agreement with the experimental data.     

Determination of characteristic parameters for the thermal decomposition of epoxy resin/carbon fibre composites in cone calorimeter

Present study concerns to the thermal degradation of two carbon fibre/epoxy composites, which differ by their volume fractions in carbon fibre (56 and 59 vol%), investigated in cone calorimeter (under atmospheric condition with a piloted ignition). In order to study the influence of the carbon fibre amount on the composite thermal decomposition, the cone calorimeter external heat flux was varied up to 75 kW m⁻². Thus, main parameters of the thermal decomposition of two different composites determined were: mass loss, mass loss rate, ignition time, thermal response parameter, ignition temperature, critical heat flux, thermal inertia and heat of gasification. As a result, when carbon fibre fraction decreases from 59 to 56 vol%, an increase of the thermal parameters was observed: 14–18 kW m⁻² for critical heat flux, 370–435 kW s^1/2 m⁻² for thermal response parameter, 2.25–5.07 kW² s m⁻⁴ K⁻² for thermal inertia and 16–18 kJ g⁻¹ for gasification heat. By analysing the mass loss rate evolutions, a four phases thermal decomposition mechanism is proposed. In the first phase, epoxy resin is cracked to form low molecular weight gaseous species and epoxy-derived compounds. For two next phases, the combustion of epoxy resin and liquor monomer solvent is observed that induces the formation of carbon char. In the last phase, char oxidation and carbon fibre decomposition are identified. Further, during the composite decomposition process, thermal behaviour of solid matrix is changed from a thermally thick material to a thermally thin one when sample is exposed at high external heat flux above 20 kW m⁻².     

A high performance oscillatory combustor burning low-grade coal

A high-performance oscillatory combustor for burning low-grade coal was developed and operated continuously for periods of up to 24 hours. The oscillatory combustor is of extremely simple mechanical design. It has an output capacity of 15–25 kW and its system and combustion efficiencies are 65% and close to 100% respectively. The developed oscillatory combustor is environment-friendly and its pollutant emission is far below that of conventional combustors burning low-grade coal.     

330MW燃煤机组燃烧内蒙西部煤结渣性能的分析研究

文章通过对内蒙西部达电用煤的研究，采用了RTSQ综合判别法对内蒙西部煤的结渣特性进行判别，提出了降低结渣程度的设计与运行措施。     

A comprehensive study of light hydrocarbon mechanisms performance in predicting methane/hydrogen/air laminar burning velocities

In order to obtain the precise predicted values of methane/hydrogen/air burning velocities from simulations, the performances of GRI mech 3.0, Aramco mech 1.3, USC mech 2.0 and San diego mech mechanisms were systematically studied under various conditions by PREMIX code and compared with experimental data from literature. The conditions where each mechanism gave their good performance are obtained and concluded. The flowrate sensitivity and rate constants of key elementary reactions were analyzed to insight the different behavior of each mechanism. The results showed that all these widely used small hydrocarbon mechanisms could gave reasonable predictions for pure methane and methane hydrogen blends. Nevertheless, they lack sensitivity for rich hydrogen at elevated pressures due to their complex reactions competitions controlled by hydrogen sub model. USC mech 2.0 was found more suitable for being used at low hydrogen contents while San diego mech gained better results at high hydrogen contents. GRI 3.0 gave good predictions for methane hydrogen blends except for high initial pressures. Generally, Aramco mech 1.3 showed the best performance for all testing conditions. Moreover, there was relatively large deviation from the predicted results and experimental data in the transition regime where the hydrogen fractions were between 60% and 80%, it may could be optimized by tuning the rate constants of reactions.     

复合燃烧技术在链条锅炉上的应用

针对链条锅炉普遍燃烧状况不好 ,热效率偏低的现状 ,提出了把复合燃烧技术引入链条锅炉的方案 ,将层燃与室燃两种方式结合起来 ,可大为改善目前链条锅炉的燃烧状况 ,提高锅炉的煤种适应性和热效率 ,最终达到节煤和环保的双重目的。     

Numerical study on laminar burning velocity of ammonia flame with methanol addition

The combustion characteristics of ammonia/methanol mixtures were investigated numerically in this study. Methanol has a dramatic promotive effect on the laminar burning velocity (LBV) of ammonia. Three mechanisms from literature and another four self-developed mechanisms constructed in this study were evaluated using the measured laminar burning velocities of ammonia/methanol mixtures from Wang et al. (Combust.Flame. 2021). Generally, none of the selected mechanisms can precisely predict the measured laminar burning velocities at all conditions. Aiming to develop a simplified and reliable mechanism for ammonia/methanol mixtures, the constructed mechanism utilized NUI Galway mechanism (Combust.Flame. 2016) as methanol sub-mechanism and the Otomo mechanism (Int. J. Hydrogen. Energy. 2018) as ammonia sub-mechanism was optimized and reduced. The reduced mechanism entitled ‘DNO-NH3’, can accurately reproduce the measured laminar burning velocities of ammonia/methanol mixtures under all conditions. A reaction path analysis of the ammonia/methanol mixtures based on the DNO-NH3 mechanism shows that methanol is not directly involved in ammonia oxidation, instead, the produced methyl radicals from methanol oxidization contribute to the dehydrogenation of ammonia. Besides, NO_x emission analysis demonstrates that 60% methanol addition results in the highest NO_x emissions. The most important reactions dominating the NO_x consumption and production are identified in this study.