SCR系统降低NOx排放ESC稳态循环试验研究

本文通过ESC试验验证自主开发的SCR系统降低NOx排放的能力.具体研究分为四部分:首先通过原机ESC排放试验得到原机NOx排放含量和尿素理论需求量;其次,在未加装SCR催化剂情况下,开启原装DCU控制尿素喷射得到NOx排放含量;再次,加装SCR催化剂并使用DCU控制尿素喷射,得出NOx排放含量试验结果.最后,加装SCR催化剂,通过自主研发的计量泵控制尿素喷射以提高SCR系统降低NOx排放的能力.     

轻型车扩展地区实际道路NOx排放研究

基于轻型国Ⅵ柴油车安装的后处理前、后氮氧传感器进行实际道路排放RDE(real driving emission)测试和估算.测试地区分别为环境温度40℃以上的吐鲁番高温地区、海拔2 800 m的格尔木高原地区和环境温度-25℃的海拉尔高寒地区.测试结果表明:在不同环境温度和压力下,由于采用整车热管理策略,确保了选择性催化还原(selective catalytic reduction,SCR)系统内部温度处于NOx转化高效温度范围,在城市、城郊和高速工况下,NOx 的转化效率均在85％以上;相比高温地区,高原地区车辆的NOx 原排约提高3.23倍,高寒地区约提高1.81倍.现有轻型国Ⅵ车辆要满足2023年RDE法规的NOx排放限值,优化车辆原始NOx排放至关重要.     

车辆载荷和空调对重型车实际道路排放的影响

本文选取了一辆国六排放水平的城市公交车,在高温条件下开展了不同车辆载荷和空调是否开启的整车车载法(PEMS)测试.结果表明:开启空调和增加车辆载荷都会增加PEMS测试的累积功.在空载和半载两种情况下,开启空调均会降低NOx的排放.在不开空调的情况下,半载的NOx排放要高于空载的NOx排放.在开启空调的情况下,半载和空载...     

SCR降低柴油机NOx排放的理论研究和试验验证

SCR是降低柴油机NOx排放的有效措施,是柴油机NOx排放控制的关键技术。介绍了SCR技术降低柴油机NOx排放的工作机理、SCR系统构成、SCR技术在大幅度降低NOx排放方面的优势以及影响SCR系统性能稳定性的因素。SCR技术可使产品柴油机达到欧Ⅳ排放水平,最后介绍了车用柴油机SCR技术还需要解决的问题。     

NOx传感器测量实际道路NOx排放的试验研究

针对便携式排放测试系统(portable emission measurement system,PEMS)测量实际道路排气污染物中NOx比较困难的问题,提出一种简易测量整车实际作业过程中NOx排放的试验方法.分析氮氧传感器工作原理,确定传感器安装方式及计算测量方法,对比分析氮氧传感器和PEMS设备测量实际道路NOx排...     

缸内温度对柴油均质燃烧NOx排放影响的试验研究

采用在进气上止点附近进行燃油喷射,通过缸内高温残余废气促进燃油蒸发混合的方法,在单缸135柴油机上实现了柴油燃料的均质压燃(HCCI).对HCCI燃烧的燃烧特性和排放特性进行了测试分析,根据实测示功图计算了HCCI燃烧缸内温度,分析了其对NOx排放的影响,当缸内温度超过1700K时,将使HCCI燃烧的NOx排放显著增长.     

生物柴油对柴油机NOx排放影响的研究

生物柴油是由动植物油通过酯交换技术得到,作为一种无毒、可生物降解和可再生的发动机代用燃料,已受到越来越多的关注。本文论述了生物柴油对柴油机NOx排放影响的各项研究结果,从喷油时机、燃烧过程和分子结构等方面分析了生物柴油NOx排放增加的原因,并提出了重新调整发动机、改进燃料和排气后处理等解决措施。     

降低直喷发动机NOx和碳烟排放的试验研究

为了改善自然吸气直喷柴油机的排放性能，试验研究了喷油嘴孔径、喷孔锥角及喷油泵柱塞直径等参数对发动机NOx和碳烟（DS）排放的影响。试验结果表明，在保持发动机动力性及经济性的情况下，优化匹配这些参数，可以改善发动机的排放性能，使之达到美国环境保护局第二阶段非道路用途发动机排放标准的要求。     

氢内燃机NOx排放特性的试验研究

以一台2.0L氢内燃机为测试对象,对其排放及燃烧特性进行了试验研究,探讨了NOx随当量比Φ点火提前角的变化关系.试验结果表明:在Φ=0.88时,NOx生成量达到最大;在Φ<0.88时,NOx的生成量随Φ的增加而增加;在0.88<Φ<1.2时,NOx生成量随Φ的增加急剧减少;当混合气比较稀薄时,点火提前角对NOx的贡献率相对较小.研究结果可用于氢内燃机稀薄燃烧技术的开发,可有效降低氢内燃机NOx排放.     

工质加湿对柴油机NOx排放的影响

介绍了向气缸工质加水的三种方法:柴油掺水乳化法、向燃烧室直接喷水、进气空气增湿法,并分析比较了三种不同方法对柴油机排放及性能的影响。通过进气支管喷水试验得出,工质加湿对降低NOx排放效果明显,且在一定范围内能减少油耗。     

CFD study on influence of fuel temperature on NOx emission in a HiTAC furnace

The influence of the fuel temperature on NOx formation was investigated numerically. For this purpose CFD modeling of NOx emission in an experimental furnace equipped with high temperature air combustion (HiTAC) system was studied. The comparison between the predicted results and measured values have shown good agreement, which implies that the adopted combustion and NOx formation models are suitable for predicting the characteristics of the flow, combustion, heat transfer, and NOx emissions in the HiTAC chamber. Moreover the predicted results show that increase of the fuel temperature results in a higher fluid velocity, better fuel jet mixing with the combustion air, smaller flame and lower NOx emission.     

300MW对冲燃烧锅炉NOx排放特性及经济性试验研究

针对某电厂一台300 MW前后墙对冲燃烧锅炉,通过上层停运磨通入一次风,改变磨煤机组合、机组负荷、炉膛氧量以及一次风温、一次风量等参数,研究了不同燃烧方式对NOx排放及锅炉经济性的影响,提出了锅炉高效低污染运行的合理方式。     

变压器类负荷的自动控温

本文提出带变压器的电热装置自动控温的四个技术难题,并指出采用KT型晶闸管交流电力控制器(调压系列)是解决这些问题的有力手段。     

电子膨胀阀对变频压缩机排气温度控制的实验研究

排气温度的有效控制对压缩机长期正常工作有重要影响。传统的办法是采用喷液冷却,但其装置复杂、控制难度大;而以过热度和排气温度作为电子膨胀阀——干式蒸发器调节回路的双反馈信号,弥补了仅仅以过热度作为反馈信号的不足,能够同时实现对蒸发器效率、压缩机吸/排气安全的综合控制,使得制冷系统简单、易用。     

陶瓷蓄热式换热器高温空气燃烧的实验研究

采用蓄热式换热器高温空气燃烧技术,建立了工艺有害气体高温分解系统;对以高温空气燃烧技术为理论依据的蓄热式换热器高温燃烧分解系统进行了实验研究;分析了其运行特征;探讨了蓄热周期对烟气与空气进出口温度变化特性、污染物排放浓度等参数的影响;提出了最佳换向周期,并指出短周期可以有效降低NOx的排放体积分数.     

Effect of hydrogen addition to intake gas on combustion and exhaust emission characteristics of a diesel engine

The present study experimentally investigated the performance and emission characteristics of the diesel engine with hydrogen added to the intake air at late diesel-fuel injection timings. The diesel-fuel injection timing and the hydrogen fraction in the intake mixture were varied while the available heat produced by diesel-fuel and hydrogen per second of diesel fuel and hydrogen was kept constant at a certain value. NO showed minimum at specific hydrogen fraction. The maximum rate of incylinder pressure rise also showed minimum at 10 vol. % hydrogen fraction. However, it is desirable to set the maximum rate of incylinder pressure rise less than 0.5 MPa/deg. to realize low level of combustion noise and NO emission. We attempt to reduce further NO and smoke emissions by EGR. As the result, in the case of the diesel-fuel injection timing of −2 °. ATDC with 3.9 vol. % hydrogen addition, the smoke emission value was 0%, NO emission was low, the cyclic variation was low, and the maximum rate of incylinder pressure rise was acceptable under a nearly stoichiometric condition without sacrificing indicated thermal efficiency.     

低NOx燃烧与脱硝经济运行的实践

吴泾热电厂2×300MW级燃煤供热机组脱硝设备,采用低NOx燃烧加选择性催化还原法(SCR)脱硝系统.介绍了SCR的化学反应机理、反应器安装位置、分段配风燃烧技术,分析了低NOx燃烧工况和运行参数,结果证实了:对分段配风的低NOx燃烧器来说,有效控制主燃烧区的风量,在总风量不变的条件下,加大可水平摆动的分离燃烧器(SOFA)配风量和加大SOFA配风距离是有效降低NOx的生成、减轻SCR的负载、降低耗NH3的有效方式;当燃用低值煤和可磨性差煤,使相对一次风量增加时,应降低二次风的配风量,用一次风总量自动实时修正二次风的配风量是实现自动低NOx燃烧调整的有效途径;适当降低二次风与炉膛的差压是防止二次风配风不均和控制主燃烧区风量的有效方法.     

Experimental and numerical study of the influence of initial temperature on explosion limits and explosion process of syngas-air mixtures

To study the effect of initial temperature of 30, 60, 90, and 120 °C on the explosion limits and the explosion process of the syngas-air mixtures, the explosion limits were tested by the explosive limit instrument, and the flame propagation process in the spherical pressure vessel was recorded by the high-speed camera. The ANSYS Fluent 3D software was used to simulate the explosion behavior of syngas-air mixtures. The results showed that with the increase of the initial temperature, the lower explosion limit of syngas decreased and the upper explosion limit increased, and the effect of initial temperature on the upper explosion limit of syngas was greater than that on the lower explosion limit. The flame development process in the simulation was consistent with that in the experiment, propagating outward spherically until it filled the entire container. Both experimental and numerical results presented the same trend of accelerating the flame propagation speed with the increase of initial temperature. In addition, the simulation also obtained multi-dimensional transient explosion parameters that were difficult to obtain in the experiment. The explosion process of syngas was analyzed by the explosion parameters such as temperature and pressure field in the explosion area. An increase in temperature decreased the maximum explosion pressure and shortened the time to reach the maximum explosion pressure.     

柴油添加剂降低燃油消耗率及排放的试验研究

在Y4100Q自然吸气柴油机试验台架上使用0#柴油及加入6种不同添加剂的0#柴油,对两者进行比较。给出了柴油机排放物CO,HC,NOX,PM及燃油消耗率的测试结果。分析了排放物的生成机理及不同成分或不同量的添加剂对柴油机排放和燃油消耗率的影响。     

空调系统排风热回收换热器的试验研究

对用于回收空调系统余热的通风换热器进行了试验研究。在冬季工况下对其进行了性能测试。试验结果表明，该换热器具有换热效率高、阻力小的特点；在风速为2．6m/s的工况下，其换热效率达到64．5％。