燃用超低热值燃料的燃气轮机及其热力分析

提出一种基于催化燃烧方式利用超低热值燃料的方法,介绍超低热值燃料催化燃烧燃气轮机的结构组成和原理并分析技术关键点,实验验证超低热值燃料稳定催化燃烧的可行性;并以百千瓦级功率为例进行燃气轮机热力循环计算和分析,验证燃用超低热值燃料燃气轮机装置可以实现,且可以发出有效功,为燃用超低热值燃料燃气轮机系统的研制开发提供切实可行的方法和依据。     

贫燃催化燃烧燃气轮机压气机的设计及其性能分析

分析了贫燃催化燃烧燃气轮机系统中压气机的结构特点,设计了低出口宽径比、高比转速的压气机叶轮,并采用数值计算和试验2种方法预测了其工作性能.结果表明:数值计算与试验结果基本吻合,该压气机在全工况下达到设计要求,且2种结果的高压比区域、高效率区域均远离喘振线;低宽径比、高比转速压气机的设计点在高效区;随着转速的提高,此压气机的压比特性曲线在小流量区增长的趋势明显;采用低宽径比、高比转速设计的负面作用是增大了叶尖相对马赫数.     

煤矿通风瓦斯在燃气轮机中的催化燃烧特性

在不同进口温度、工作压力和当量比条件下,研究了煤矿通风瓦斯气在燃气轮机催化燃烧室内部的燃烧特性,对数值模拟结果与试验结果进行了对比,并分析了催化燃烧对超低浓度瓦斯气性能的影响.结果表明:增加甲烷浓度(或当量比)可促进超低浓度甲烷的催化燃烧;提高催化燃烧室进口温度或工作压力可相应提高煤矿通风瓦斯燃气轮机系统的效率.     

天然气预混催化燃烧的特性

制备了1%(质量比)Pd/Al_2O_3陶瓷蜂窝催化剂,并用钡、镧、铈等氧化物对其进行改性,然后负载在堇青石载体上,并进行天然气预混催化燃烧实验。研究了空燃比、功率对催化燃烧尾气排放的影响,结果表明,催化燃烧温度在500～900℃时,空燃比、气体流速都会对催化燃烧效果产生影响;当空燃比在8.3～19时,可实现稳定催化燃烧;空燃比在11～19时催化燃烧效果较好,尾气中CO几乎为零,HC低于10~(-5),NO_x低于5×10~(-6)。     

燃气轮机燃烧脉动现象及抑制方法研究

某燃气轮机电厂经常出现因燃烧脉动所引起的部件损坏故障。给出了燃烧脉动机理,分析了燃机燃烧脉动和部件损坏故障,介绍了燃机动压监测系统在两台燃机上的应用情况,指出通过燃机动压监测系统可以有效地监测燃烧脉动现象,对提前发现燃烧故障并及时进行燃烧调整有很大帮助,可在一定程度上缓解燃烧故障对设备带来的不利影响。     

烷烃催化燃烧的数值模拟

对甲烷、乙烷在表面涂有催化剂的微元管内的催化燃烧进行了模拟．讨论了微元管入口速度、直径、入口温度以及混合气中甲烷与氧气的摩尔比对甲烷催化燃烧特性的影响;分析了单体式蜂窝块中甲烷的着火温度及单个微元管中气体温度、主要气相组分与表面组分的质量分数的变化趋势．分析了不同混合气及不同混合气摩尔比下乙烷的催化燃烧特性,数值模拟结果与实验结果基本一致;提出了碳原子数为3或大于3的烷烃催化反应简化机理的建立方法．为在内燃机中实现催化燃烧以降低氮氧化合物、未燃碳氢化合物及一氧化碳的排放,及扩展燃烧极限提供了理论依据．     

燃气轮机催化燃烧室的实验研究

介绍了预混和催化燃烧相结合的燃烧室原理,对此种燃烧室进行实验研究,分析了影响催化燃烧的主要因素。预混与催化燃烧相结合能延长催化剂的使用寿命,改善燃烧室的可靠性,更经济地降低燃气轮机ＮＯｘ的排放。     

浅论燃气轮机烧重油

燃气轮机以重油作为燃料 ,可有效地降低运行成本 ,因此颇受重视。本文简要说明了燃气轮机燃用重油技术的成熟性 ,并对我国目前燃用重油燃气轮机的情况进行了统计。文章分析了燃气轮机烧重油在燃烧、结垢、腐蚀等方面所产生问题的原因及后果 ,并针对这些问题提出了在燃油处理、燃烧系统、燃油系统和机组运行维护等方面所应采取的对策。     

微型燃气轮机燃烧室性能的数值研究

针对Capstone公司的C30微型燃气轮机的燃烧室，采用κ—ε湍流模型、EBU—Ambenius湍流燃烧模型描述其燃烧流动，采用扩展Zeldivch机制描述HOx生成；应用分区结构化网格和SIMPLE算法求解控制方程，进行了三维燃烧流动的数值模拟研究，同时对燃烧室的整体性能进行了分析。通过数值计算及结果分析，着重研究了环型贫燃预混燃烧室的燃烧组织形式对燃烧室性能的影响，并探讨了流动控制板对燃烧室内燃烧流动和燃烧室出口HOx分布的影响。数值研究的主要目的是配合新型微型燃气轮机的研制，获得微型燃气轮机燃烧室的设计经验，为研制既有高燃烧效率和燃烧稳定性，又有低HOx排放特性的燃烧室奠定基础。     

催化燃烧对均质压燃发动机燃烧特性影响的数值模拟

通过运用DETCHEM软件包,对甲烷在催化剂Rh表面的详细反应机理进行了分析,结果表明数值模拟结果与实验数据相当吻合;通过耦合DETCHEM软件包及CHEMKIN软件包中的SENKIN模块,对活塞顶涂有催化剂铑的均质压燃(HCCI)发动机的燃烧过程进行了数值计算,建立了单区和多区模型．利用单区模型分析了催化燃烧对HCCI发动机着火时刻的影响,同时讨论了催化燃烧对燃烧过程中主要化学组分浓度变化的影响,结果表明催化燃烧会使HCCI发动机着火时刻提前;利用多区模型分析了催化燃烧对HCCI发动机的未燃碳氢化合物(UHC)、氮氧化合物(NOx)排放的影响,结果表明催化燃烧能降低UHC的排放,但会提高NOx的排放．     

超燃模型发动机中引入催化重整燃气的试验研究

催化重整燃烧室能够产生氢体积分数高达16%的高温富油可燃燃气,所产生的可燃燃气从后支板供入到超燃模型发动机中,进行了直连式联调试验.在相同超音速来流状态下,与不通入可燃燃气的两种工况进行了压力、出口火焰形貌和壁面温度的对比,发现可燃燃气的加入能够在几乎不加入高压气堵情况下迅速着火,并能维持住稳定的超音速燃烧,在富油恶劣状态下,燃烧良好.结果表明,催化重整可燃成分在超燃模型发动机中起到了助燃和稳定燃烧的作用.     

燃烧法控制有机废气污染的催化剂性能研究

用爆炸法制备烯土钙钛矿型第列催化剂,以甲苯的燃烧为模型反应,对比非催化燃烧法,发现催化燃烧法具有反应温度低,热量消耗少的优点,通过XRD,TPR和活性评价等测试,得到该类催化剂在催化燃烧反应中起关键作用的因素是它具有低结合能的吸附氧。     

Thermal management and catalytic combustion stability characteristics of premixed methane/air in heat recirculation meso‐combustors

In order to illuminate heat recirculation effect on catalytic combustion stability and further improve energy conversion efficiency in meso‐combustor, the catalytic combustion characteristics of the combustor with/without preheating channels are numerically studied at steady conditions. It is found that methane conversion rate and combustion efficiency increases by 2% to 3% and approximately 9% in the heat recirculation meso‐combustor, indicating that heat recirculation effect facilitates more complete combustion of methane and medium components. Preheating channels show positive effects on improving combustion stability in the heat recirculation meso‐combustor. On one hand, preheating channels facilitate heat recirculation effect, and heat recirculation rate exceeds 10% for all cases and reaches 31.8% with an inlet velocity of 0.5 m/s, leading to significant increment of methane‐specific enthalpy at the preheating channel outlet. On the other hand, Rh(s)/O(s) ratios of catalytic surface and catalytic surface temperature in main reaction zone are enlarged by the preheating channels, facilitating methane adsorption at catalytic surface. Specially, most of fuels are consumed in a shorter distance with higher methane conversion speed, which brings benefits to promote combustion efficiency and may be helpful to inhibit the combustion instability in heat recirculation meso‐combustors.     

Application of distributed combustion technique to hydrogen-rich coal gases: A numerical investigation

Distributed combustion has been a promising combustion technique, for enabling a more uniform thermal field, resulting in ultra-low pollutant emissions, reduced combustion noise, and enhanced combustion efficiency. This work examines combustion of hydrogen-rich coal gases derived from Turkish coal under distributed combustion conditions. Focus here is on obtaining a broadened flame and reducing pollutant emissions. Numerical modelling was carried out using a commercial code in order to predict the thermal field and pollutant emissions of the hydrogen-rich coal gases under distributed combustion conditions. A gas mixture (90% N₂ and 10% CO₂) was utilized to simulate controlled entrainment of hot reactive product gases into the fresh mixture prior to ignition in order to seek distributed combustion. The results showed that distributed combustion provided far more uniform thermal field that resulted in greatly reduced NOx emissions. The results also showed that the temperature difference between the maximum and exit temperature was reduced to approximately 200 K under distributed conditions. In addition, the NOx pollutant emissions predicted for each gas were reduced to near zero levels under high intensity distributed combustion conditions supporting the available experimental data. It has been concluded that enhanced thermal field uniformity and significantly reduced NOx emissions were achieved for hydrogen-rich coal gases under distributed conditions.     

Catalytic combustion of hydrogen for residential heat supply application

Hydrogen can be converted to thermal energy by combustion or to electricity energy by fuel cells. Considering the stringent requirements for safety from fire hazards and elimination of pollutants, the flameless catalytic combustion of hydrogen is favorable over conventional flame combustion for residential heat supply application. This paper reported an industrial‐scale heat acquisition system based on hydrogen catalytic combustion. The 1 wt% Pt‐loaded glass fiber felts prepared by an impregnation process were used as the combustion catalyst, and a catalytic combustion burner with a capacity of 1 kW was designed. It was found that 100% hydrogen conversion rate could be obtained during the stable combustion stage, and the stable combustion could be achieved by adjusting hydrogen flow rate. The change in H₂/air ratio would influence the initial combustion stage but has little impact on the stable combustion stage. A heat efficiency of 80% for hot water supply was obtained based on the present catalytic hydrogen combustion burner. Copyright © 2016 John Wiley & Sons, Ltd.     

Catalytic combustion for industrial gas turbines

This brief review provides a general account of work directed at the use of catalytic combustion in gas turbine engines. A major potential advantage of using catalytic combustion is that the fuel can be burnt efficiently at temperatures low enough (< 1500°C) to avoid significant oxidation of atmospheric nitrogen. This advantage was less important when catalytic combustion was demonstrated in the 1970s than it is today and received relatively little attention until the following decade. After discussion of the principles involved in the design of a combustor that must meet the mixing, size, performance and durability goals of a based gas turbine application, the review turns to accounts of experiments conducted on a laboratory scale with simple configurations. These established basic operating parameters for satisfactory combustion performance and led to larger scale work and to prototype design concepts for industrial gas turbines in the late 70s and early 80s. Test results were encouraging but were not pursued definitively in the U.S.A. Activity continued at several centres in Japan, with exploration of a number of different catalyst arrangements, geometries, and control systems, again with encouraging results. At the same time, there has been renewed interests in the U.S.A. and in Europe, spurred largely by the emphasis on reducing emissions of nitrogen oxides (NOx). The paper concludes with suggestions for further development of catalytically stabilized combustion systems for gas turbines. These systems must ensure adequate pre-catalyst temperature, with evenly premixed fuel and air, and sufficient temperature rise across the catalyst to ensure effective completion of reaction in a homogeneous reaction mode. The outstanding problems are largely concerned with questions of catalyst integrity and longevity in practical configurations and realistic engine operating conditions.     

A fibre‐mat catalytic burner for the heating system of PVC tiles

This study aims to develop the low‐temperature catalytic burner using Al₂O₃ fibre and Pt catalyst as a substrate and an active material, respectively, and then to apply it to the heating system of PVC tiles. Three types of fibre‐mat catalytic burners—natural diffusion catalytic burner, forced diffusion catalytic burner and premixed catalytic burner—were tested. For the natural diffusion catalytic burner, the combustion efficiency was significantly affected by the installation method. Its combustion efficiency was above 99.5% when it was placed vertically and upward, whereas the combustion efficiency rapidly deteriorated to less than 80% when it was installed in downward position. When the forced diffusion combustion mode was employed, the combustion efficiency of the fibre‐mat catalytic burner was successively improved over 99.5%. The optimal operation condition of the premixed fibre‐mat catalytic burner was obtained when the excess air ratio is 4.3 and the heat load is 3.0 kcal h^?1 cm^?2. The heat load of the premixed catalytic burner was found to be twice as much as those of the natural and forced diffusion catalytic burner, meaning that the size of the catalytic burner can be reduced to its half if the premixed catalytic burner is used. We also performed the field test of the fibre‐mat catalytic burner in the heating system of the PVC tiles. The combustion efficiency of the catalytic burners appeared to be satisfactory, above 99.5%, and the energy saving by replacing the existing electrical heaters with the fibre‐mat catalytic burners were shown to be 27.7%. Copyright © 2002 John Wiley & Sons, Ltd.     

氢气预混合微尺度催化燃烧的数值模拟

通过耦合计算流体力学软件FLUENT和化学反应动力学软件CHEMKIN并采用空间气相和表面催化详细化学反应机理,对氢气和空气的预混合气体在微型管道内的催化燃烧过程进行了数值模拟,讨论了不同反应模型的燃烧特性以及预混合气体入口速度、当量比Φ和管径对催化燃烧反应的影响。计算结果表明：表面催化反应对空间气相反应有抑制作用;随着入口速度的增大,燃烧过程同时存在着表面催化反应和空间气相反应两种控制因素;当量比Φ和管径对氢气的催化燃烧过程有重要的影响。