燃机氮氧化物排放研究及脱硝技术探讨

在天然气燃机启停及低负荷运行过程中,燃机排气氮氧化物浓度较高,烟囱会出现冒"黄烟"现象。对某9F燃机的排气进行测试,分析其中氮氧化物生成的规律。探讨燃机氮氧化物生成机理和脱硝技术,提出燃机启停及低负荷时消除"黄烟"的解决方案。     

2014GTW简单循环技术规范

正据《Gas Turbine World》2014年1-2月刊发布了2014年度燃气轮机简单循环技术规范。介绍了世界各国各燃机制造公司的各型燃气轮机产品,叙述了各型燃气轮机的设计性能及规范,包括首台可用年份、ISO条件下基本负荷额定功率、热耗率、效率、压气机压比、质量流量、涡轮转速、排气温度、以及燃气轮机的重量和尺寸。在注解一栏中还对这些燃机是否使用双燃料燃烧器、标准燃烧室、干式低NOx燃烧室、干式低排放、     

生物柴油发动机的催化型连续再生系统的仿真研究

建立了CCRT系统模型,并根据试验参数对模型进行了标定。分别比较了不同工况下,燃用B20、BD50、BD100时DOC对常规排放气体的转化效率以及CPF的颗粒物再生情况。发现:DOC对NO的转换效率各工况差别较大,主要受排气温度影响;对CO及HC整体转化效率处于较高水平,去除效果较为理想。平衡时CPF内残留的颗粒物质量随转速升高而增加,随负荷增加而减少;低负荷、高转速工况是CPF再生效果最差的工况。随着生物柴油掺混比例的上升,DOC的NO_2出口浓度及NO转化效率上升,而对DOC的HC和CO去除效果影响较小; CPF残留颗粒物质量在高转速区域有所下降,而在中低负荷区域有所上升。主要原因是燃用生物柴油引发的排气温度降低和颗粒物排放降低。低负荷、高转速工况下,燃用BD50时CPF的再生效果最佳。     

燃气轮机驱动压缩机组负荷控制参数波动问题研究

西气东输工程燃气轮机驱动压缩机组控制系统负荷控制功能不完善,造成机组在压力自动控制模式下,燃机、压缩机的转速和排气温度等重要参数在运行过程中极不稳定,并呈现周期性振动特性,对燃机重要部件造成严重的低周疲劳损伤。本文对机组的控制方式进行了研究,分析了机组功率、转速、排气温度波动的机理,通过合理调整控制器参数解决了机组关键参数波动的问题,显著改善了机组的运行稳定性和可靠性,对于提高机组的使用寿命、降低热部件的疲劳损耗具有主要作用。所做工作对机组控制系统的设计和调整具有参考价值。     

2014GTW简单循环技术规范

正《Gas Turbine World》2014年1-2月刊发布了2014年度燃气轮机简单循环技术规范。介绍了世界各国燃机制造公司的各型燃气轮机产品,叙述了各型燃气轮机设计性能及规范,包括首台可用年份、ISO条件下基本负荷额定功率、热耗率、效率、压气机压比、质量流量、涡轮转速、排气温度以及燃气轮机的重量和尺寸。在注解一栏中还对这些燃机是否使用双燃料燃烧器、标准燃烧室、干式低NOx燃烧室、干式低排放、NOx排放、喷水、蒸汽回注、天然气燃料和双燃料、回热、拖车装载、60 Hz或50 Hz、可用于50 Hz和60 Hz、低热值燃料等情况作了补充说明。2012年推出新机组包括功率达6 520 k W和效率达32.0%的MGT6100、功率达14 400 k W和效率达     

基于F级燃气轮机烟气再循环系统的分析

分析了烟气再循环技术直接应用于F级燃气轮机联合循环时对燃气热力循环参数的影响.对比分析了余热锅炉后排气分别按照无烟气循环和烟气再循环比例为10%、20%和30%的工况,烟气再循环在联合循环条件下燃气轮机进口温度与进口氧体积分数的变化趋势,以及不同烟气再循环比例条件下联合循环出力的变化趋势;计算了不同负荷条件下烟气再循环对燃气轮机本体透平进口温度及排气温度的影响;分析了烟气再循环对潜在CO_2捕集的优势.结果表明:烟气再循环可在部分负荷下提升联合循环效率,并且有助于CO_2捕集.     

9FA燃气轮机排气温度测量元件优化

燃气轮机(以下简称燃机)排气温度是燃机运行时的重要监控参数,关乎燃烧系统的安全和燃烧工况稳定.燃机排气温度采用热电偶测量,热电偶元件的可靠性始终是热控维护关注的重点.从选型、安装等方面介绍了某电厂9FA型燃气轮机排气热电偶的优化,可为类似机组提供一定参考.     

双介质NTP反应器预氧化柴油机NO的试验研究

建立双介质低温等离子体(NTP)反应器预氧化柴油机NO台架试验系统,研究了放电电压峰峰值V_(p-p)、放电频率、排气流量及负荷对NTP预氧化NO性能的影响。试验结果表明:2 100r/min转速、0%负荷工况下,相同放电频率时,NO体积分数随V_(p-p)增大而先减小后增大,NO_2体积分数随V_(p-p)增大而增大,NO_x总量随V_(p-p)增大而先减小后增大;不同放电频率时均存在一个能使NO/NO_2比例为1∶1的V_(p-p)临界值点。排气流量对NTP氧化NO性能影响不大。随着负荷的增大,NTP氧化NO的能力逐渐减弱,其中0%负荷和25%负荷时,NTP能使NO/NO_2比例达到1∶1,协同选择性催化还原(SCR)系统可实现快速SCR反应,提高柴油机低温区间NO_x的转化率。     

燃气轮机并网吹管的可行性分析

当前燃气轮机机组吹管过程中,燃气轮机转速维持3 000 r/min,蒸汽温度只有300℃左右,吹管效果差,且燃气成本高。蒸汽温度超过350℃时,氧化皮脱落剧烈,吹管效果好。在吹管期间,并网后发现燃气轮机排气温度明显提高,高压过热器出口蒸汽温度和再热器出口蒸汽温度也随之明显提高。在对比不同负荷下的燃气使用量,可以发现负荷越高其相应的成本反而越低。因此,新建燃气轮机机组在吹管期间,可以选择低负荷并网吹管,增强吹管效果的同时降低了成本,也缩短了工期。     

基于LabVIEW的燃气轮机发电机组测控系统设计

采用基于NI CompactRIO控制器开发的燃气轮机发电机组测控系统,利用LabVIEW语言开发了具有燃机启动控制、闭环式转速控制及温度保护功能软件,对开发的测控系统进行突增和突降燃机25%负荷的试验。结果表明,本测控系统在突增或突降负荷时,使燃机最大瞬时减速或增速不超过设定转速的7%,能够在负荷变化很短时间内恢复到与最终稳态转速的偏差小于1%,满足船舶燃气轮机通用规范的要求。     

Catalytic oxidation of NO to NO2 on activated carbon

Catalytic oxidation of NO to NO₂ over activated carbons PAN-ACF, pitch-ACF and coconut-AC at room temperature (30°C) were studied to develop a method based on oxidative removal of NO from flue gases. For a dry gas, under the conditions of a gas space flow rate 1500 h⁻¹ in the presence of oxygen of 2–20% in volume concentration, the activated coconut carbon with a surface area 1200 m²/g converted about 81–94% of NO with increasing oxygen concentration, the pitch based activated carbon fiber with a surface area 1000 m²/g about 44–75%, and the polyacrylonitriale-based activated carbon fiber with a surface area 1810 m²/g about 25–68%. The order of activity of the activated carbons was PAN-ACF<pitch-ACF<coconut-AC. However, NO conversion markedly decreased with the increases in temperature and humidity. For the dry gas, the apparent reaction rate was expressed by an equation: R=k_cP_NOP_O2^β (F/W), where β is 0.042, 0.16, 0.31 for the coconut-AC, the pitch-ACF and the PAN-ACF respectively, and k_c is 0.94 at 30°C.     

NOx生成湍流反应率的二阶矩—PDF数值模拟

将对NOx生成湍流反应率模拟的二阶矩模型和设定PDF模型结合起来，提出一种氮氧化物生成湍流反率的二阶矩－PDF模型，以兼顾解决工程的合理性和经济性，并对甲烷空气燃烧中的NOx生成进行了数值模拟。     

单角煤粉炉中NOx生成的数值模拟

根据NO产生和分解的化学反应规律，建立了NOx生成模型。在单角炉热太实验的基础上，对波纹钝体和直流喷口后金个戴面上的NO生成速率和浓度进行了数值模拟。将计算所得的NOx生成总浓度与实测值进行了比较，验证了计算的可靠性。还讨论了影响NOx生成的因素，以及反应级数的大小。     

NO Relaxation Approach (NORA) to predict thermal NO in combustion chambers

In combustion models employing tabulated or global kinetics, the prediction of thermal NO is usually performed by either the direct resolution of Zel’dovich mechanism or the tabulation of the NO reaction rate using a laminar flamelet database and a progress variable representative of the fuel oxidation reactions, for instance temperature or a linear combination of major products mass fractions. It is known that the first method lacks accuracy if radical species such as N or O appearing in the NO reaction rate are not correctly estimated. The second method cannot lead to accurate predictions because NO reactions take place essentially when the fuel oxidation is over, therefore the NO reaction rate shows a very weak correlation with the progress variable. In this paper a new approach called NO Relaxation Approach (NORA), is proposed for the modeling of thermal NO. It allows a high accuracy when coupled with this type of combustion models. With NORA, the NO reaction rate is written as a linear relaxation towards the equilibrium value with a characteristic time τ. Both parameters are tabulated as functions of equivalence ratio, pressure, temperature and dilution mass fraction. NORA is first validated on homogeneous internal combustion engine cases, where it closely fits the complex chemistry results. It is then integrated into the turbulent combustion model ECFM3Z dedicated to piston engine applications. In this model a mixed tabulated (TKI) and global kinetics (CORK) approach is used to describe turbulent combustion. First applications on eight Diesel engine operating points show a good improvement with NORA compared to a classical resolution of Zel’dovich mechanism.     

无烟煤焦炭对NO的还原率

采用双管式固定床试验台,直接通入无烟煤粉燃烧产生烟气与焦炭反应,以此模拟真实无烟煤粉燃烧气氛,研究无烟煤焦炭对NO还原率的影响因素.研究发现,无烟煤焦炭还原NO效果显著,燃烧温度的提高利于增加还原率;粒径并非越细越好,而是存在着一个最佳还原粒径尺寸;无烟煤焦炭的比表面积是影响其还原率的关键因素;CO与CO2体积的比值可以表征无烟煤焦炭的还原率,值越小表明活性越强.     

洛阳石化4号、5号汽轮机节能优化运行

中国石化洛阳分公司有三台在役余热发电机组,2008年后由于催化工艺变化,中压蒸汽产量不足,故1号机长期停运,4号机、5号机运行,且5号机一直维持纯凝工况。由于机组汽耗率和机组设备状况、机组负荷、实际主汽、排汽参数等多种因素有关,实际机组的汽耗率应是一条与理论值存在一定偏移量的近似直线。文中机组供热发电的汽耗率就是供热蒸汽发电的汽耗率。利用大量的运行统计数据,进行统计建模、求解的方法获得4号机、5号机发电汽耗率曲线,并进行对照分析,得到4号机维持空转需要8.37t/h蒸汽,且5号机的电效率略高于4号机的结论。计算结果显示,如果停掉4号机,将4号机的供热蒸汽量改由5号机抽汽来供应,在同样的中压蒸汽流量和供热蒸汽量情况下,可增加发电负荷0.57MW/h,按照每年运行8400h计算,则每年可增加发电量478.8×104kW.h。     

NO formation in counterflow partially premixed flames

An experimental and computational study of NO formation in low-strain-rate partially premixed methane counterflow flames is reported. For progressive fuel-side partial premixing the peak NO concentration increased and the NO distribution along the stagnation streamline broadened. New temperature-dependent emissivity data for a SiO₂-coated Pt thermocouple was used to estimate the radiation correction for the thermocouple, thus improving the accuracy of the reported flame temperature. Flame structure computations with GRIMech 3.00 showed good agreement between measured and computed concentration distributions of NO and OH radical. With progressive partial premixing the contribution of the thermal NO pathway to NO formation increases. The emission index of NO (EINO) first increased and then decreased, reaching its peak value for the level of partial premixing that corresponds to location of the nonpremixed reaction zone at the stagnation plane. The observation of a maximum in EINO at a level of partial premixing corresponding to the nonpremixed reaction zone at the stagnation plane seems to be a consistent feature of low (<20 s⁻¹)-strain-rate counterflow flames.     

烟煤焦催化还原NOx实验研究

研究了烟煤焦在催化剂的作用下对Nx的还原过程。实验发现，烟煤焦中 廉价催化剂的存在对煤焦异相还原NOx有很大的影响，在合适的反应温度和化学当量比（SR）条件下，煤焦中的催化剂能降低NOx还原反应的活化能，加快NOx还原反应的速度，提高NOx的还原率。实验使用两种催化剂后，NOx的还原率可超过50％，几乎达到与褐煤及气体再燃烧相同的再燃效果。     

Control of NO emission during coal reburning

In this study, two types of coals were used as the reburning fuel to investigate the influence of the reburning zone stoichiometry SR₂, the primary NO level and the particle size on NO reduction. For both coals, the NO reduction can reach as high as 60–70% in the tested SR₂ range of 0.7–1.1. No optimum reburning zone stoichiometry was observed in this study. The NO reduction decreases monotonically with the decrease of reburning zone stoichiometry. The effect of particle size is only obvious for larger particle sizes.