摩托车催化转化器性能台架考核装置改进

摩托车催化转化器性能台架考核方法,可以快速有效的评价催化器的性能.在本文中对原有的试验装置进行了改进.设计了电喷系统对空燃比进行调节,设计了换热器对催化器入口温度进行调节.试验结果证明改进后的装置可以提高空燃比和入口温度的控制精度,满足快速准确的评价催化器性能的要求.     

摩托车催化转化器性能台架评价装置改进及试验研究

针对原摩托车催化转化器台架性能评价存在控制精度不高及调整不方便的缺点,对评价试验装置进行了改进。采用电控系统控制空燃比,设计了翅片管式换热器调节催化器入口温度。试验表明,改进后空燃比的波动可控制在0.1以内,入口温度波动在±2℃以内。利用该台架对MLKV 102-2催化器的性能进行了研究,试验结果表明该台架可以快速有效地评价催化器的性能。     

摩托车催化器性能及快速老化台架评价试验研究

根据国内外汽车催化器性能台架评价方法 ,结合摩托车工作特点 ,建立了摩托车催化器性能及快速老化台架评价试验装置。采用该装置可以实现催化器快速老化所需要的高温氧化条件 ,老化中空燃比波动模式和老化时间可变动调整 ,可评价催化器的空燃比特性、起燃温度特性、空速特性和起燃时间特性。试验结果表明 ,上述试验装置可以满足试验要求 ,结果可靠     

摩托车催化性能考核台架换热器的设计及试验

催化器性能评价试验中,需要调节、控制催化器的入口温度,本文设计了冷轧翅片管、整体轧制式、U型管壳式换热器和单程管壳式换热器,并对四种换热器进行了比较,选定冷轧翅片管换热器进行试验,试验结果表明设计的冷轧翅片管式换热器能够较好的对催化器入口温度进行控制,实用性较好。     

摩托车催化性能考核台架换热器的设计及试验

催化器性能评价试验中,需要调节、控制催化器的入口温度,本文设计了冷轧翅片管、整体轧制式、U型管壳式换热器和单程管壳式换热器,并对四种换热器进行了比较,选定冷轧翅片管换热器进行试验,试验结果表明设计的冷轧翅片管式换热器能够较好的对催化器入口温度进行控制,实用性较好.     

换热器在摩托车催化器性能台架中的应用

为满足摩托车催化器性能考核台架对催化器入口温度控制的要求,设计了冷轧翅片管和单程管壳式两种换热器,并分析对比了这两种换热器的优缺点,根据对温度控制的要求和试验台架的空间布置特点,选定冷轧翅片管换热器控制催化器入口温度,试验结果表明该换热器能够连续调节催化器入口温度,控制温度波动在±2°C之间,可以满足试验要求。     

两种天然气专用氧化型催化器的对比试验研究

对两种天然气专用氧化型催化器进行了空燃比和起燃温度特性试验,对比并分析了试验结果,初步了解了两种催化器对天然气发动机排放的净化能力以及它们之间的性能差异。     

摩托车催化器性能考核台架试验中换热器的研究

催化器性能评价试验中，起燃特性和温度特性是两个重要性能，这两个特性的研究都需要对催化器入口温度进行稳定连续的调节。本文设计了冷轧翅片管、整体轧制式、U型管壳式换热器和单程管壳式换热器，通过比较，选定冷轧翅片管换热器进行温度特性和起燃特性试验，试验结果表明该换热器能够达到设计要求，对温度的控制也比较稳定。     

吸附还原法还原过程中空燃比控制策略的试验研究

运用研制设计的新型稀燃尾气催化系统和恒转矩电控系统,对稀Nox吸附还原催化器(LNT)还原过程中空燃比大小和浓、稀燃时间比值及长短对稀燃发动机性能进行了试验研究,结果表明:还原过程空燃比大小和稀、浓燃时间比值及长短不仅对发动机的输出转矩大小、燃油消耗率等性能有影响,而且对发动机的排放特性也有重要影响.稀Nox吸附还原催化器还原过程空燃比越小和浓、稀燃时间比值越大、浓燃还原时间越长,Nox还原越彻底,Nox排放越低,但稀燃发动机的比油耗稍变大,经济性变差.因此,在应用LNT降低稀燃发动机Nox排放时,需要对其还原过程空燃比大小和浓、稀燃时间比值及长短进行优化.     

摩托车台架实验空燃比控制系统的开发

本文介绍了用于摩托车台架实验的空燃比控制系统,可用于在台架上进行摩托车催化器性能的考核。系统主要分为上位机和下位机两部分,下位机控制喷油时刻喷油持续期及喷油量,从而实现了对空燃比的控制;上位机可以完成各种参数的监测和采集。     

稀燃汽油机空燃比电控系统研制

NOx吸附-还原催化转化器可以高效地净化稀燃汽油机的NOx有害排放物。为了配合稀燃NOx吸附-还原催化转化器的正常工作，稀燃汽油机需周期地工作在浓燃和稀燃之间，这就需要空燃比控制系统不仅可以任意设定浓、稀燃的空燃比大小，而且还可以任意设定浓、稀燃的间隔时间长短。本文介绍了稀燃汽油机空燃比电控系统的研制情况。     

Validation of measured data on F/A ratio and turbine inlet temperature with optimal estimation to enhance the reliability on a full-scale gas turbine combustion test for IGCC

This study is aimed at verifying the reliability and reproducibility of combustion tests, including ignition, load change and fuel changeover, conducted at a well-resourced full-scale gas turbine syngas combustion test facility. The 10 MWth, single-can, syngas-fired combustion test facility was equipped with analytical equipment to measure air and fuel flow rates to the combustor, the metal/gas temperature in the combustor, and exhaust gas composition and temperature distribution at the combustor's outlet.To confirm the test facility's reliability, the repeatability of the fuel changeover test from natural gas to syngas was evaluated. Reliability was also verified by cross-validating the theoretical and measured values for fuel/air (F/A) ratio and Turbine Inlet Temperature (TIT). In this study, the deviation between the averaged F/A ratio based on O₂ and CO emission data and the F/A ratio based on the mass flow rate was under 2% at most, when the F/A ratio exceeded 20%. And, the calculated TIT for syngas, taking thermal dissociation and heat loss into consideration, correlates well with the experimental result which is the corrected TIT value based on heat balance at the temperature sensor tip.     

Oriented linear cutting fiber sintered felt as an innovative catalyst support for methanol steam reforming

A kind of oriented linear cutting fiber sintered felt as an innovative catalyst support for methanol steam reforming was proposed. Multiple long copper fibers fabricated by cutting method were arranged in parallel and then sintered together in a mold pressing equipment under the condition of high temperature and protective gas atmosphere. The characteristics of oriented linear cutting fiber sintered felt coated with Cu/Zn/Al/Zr catalyst for methanol steam reforming were experimental investigated under different GHSVs and reaction temperatures. Results indicated that the structure of sintered felt was the key influencing factor for the reaction performances on the condition of low GHSV or reaction temperature whereas the structure of sintered felt showed little influences with high GHSV or reaction temperature. By the analysis of SEM image and ultrasonic vibration testing method, it was found that the coarse surface pattern of cutting fiber could effectively enhance the adhesion intensity between the catalyst and the copper fibers, as well as present relatively large specific surface area in the microchannels. And hence the oriented linear cutting fiber sintered felt present better performances of methanol steam reforming than the oriented linear copper wire sintered felt on the condition of low GHSV or reaction temperature.     

Effects of Polymerization and Briquetting Parameters on the Tensile Strength of Briquettes formed from Coal Coke and Aniline-Formaldehyde Resin

In this work, the utilization of aniline (C₆H₇N) formaldehyde (HCHO) resins as a binding agent of coke briquetting was investigated. Aniline (AN) formaldehyde (F) resins are a family of thermoplastics synthesized by condensing AN and F in an acid solution exhibiting high dielectric strength. The tensile strength sharply increases as the ratio of F to AN from 0.5 to 1.6, and it reaches the highest values between 1.6 and 2.2 F/AN ratio; it then slightly decreases. The highest tensile strength of F-AN resin-coke briquette (23.66 MN/m²) was obtained from the run with 1.5 of F/AN ratio by using (NH₄)₂S₂O₈ catalyst at 310 K briquetting temperature. The tensile strength of F-AN resin-coke briquette slightly decreased with increasing the catalyst percent to 0.10%, and then it sharply decreased to zero with increasing the catalyst percent to 0.2%. In general, the tensile strength of F-AN resin-coke briquette increased as increased the briquetting temperature in these tests contras with NaOH catalytic runs. The effect of pH on the tensile strength is irregular. As the pH of the mixture increases from 9.0 to 9.2, the tensile strength shows a sharp increase, and the curve reaches a plateau value between pH 9.3 and 9.9; then the tensile strength shows a slight increase after pH = 9.9.     

A kinetic model for analyzing partial oxidation reforming of heavy hydrocarbon over a novel self-sustained electrochemical promotion catalyst

A kinetic model for analyzing catalytic partial oxidation reforming (POXR) of n-pentadecane over a novel self-sustained electrochemical promotion (SSEP) catalyst which accelerated the reaction rate at relatively lower temperatures below 650 °C was proposed. The SSEP-POXR model consists of two parts: a conventional Langmuir–Hinshelwood (L–H) model, describing normal partial oxidation reforming and a new model describing the SSEP mechanism. The kinetic parameters of L–H model were estimated by curve-fitting experimental results of POXR of n-pentadecane on a conventional Ni/NiO/Cu/CeO₂ catalyst whereas those for the SSEP process were evaluated using typical geometric configurations of components of the SSEP catalyst and their electrochemical properties. The SSEP-POXR model was used to establish a relationship between input and output parameters and explain the trend of the experimental results in terms of the impact of temperature on the fuel conversion. The computational results agreed well with experimental results of the POXR of n-pentadecane on the SSEP catalyst in a temperature range of 450–650 °C. The maximum error of computational results of fuel conversion was 3.1% in the reaction temperature range. The SSEP-POXR model is capable of quantifying the enhancement of the fuel conversion attributed to the SSEP process.     

The performance of nickel-loaded lignite residue for steam reforming of toluene as the model compound of biomass gasification tar

Tars should be removed from biomass gasification systems so as not to damage or clog downstream pipes or equipment. In this paper, lignite insoluble residue (LIR) after extraction of humic acids was used as the support to prepare a nickel-loaded LIR (Ni/LIR) catalyst. This novel catalyst Ni/LIR was tested in steam reforming of toluene as a model compound of biomass tar conducted in a laboratory-scale fixed bed reactor. When compared to the reactions without catalyst or with Ni/Al₂O_3, Ni/LIR was confirmed as an active catalyst for toluene conversion at a relatively low temperature of 900 K. The investigated reforming parameters during the experiments in this research were selected as reaction temperature at a range of 850–950 K, steam/carbon molar ratio at a range of 2–5 mol/mol, and a space velocity from 1696 to 3387 h^?1. It was concluded that, under optimum conditions, significant amount of syngas yields, acceptable Ni/LIR consumption and more than 95% of toluene conversion can be obtained from the biomass Ni/LIR catalytic gasification system.     

A study of steam methanol reforming in a microreactor

Steam reforming of methanol is investigated numerically considering both heat and mass transfer of the species in a packed bed microreactor. The numerical results are shown to be in good agreement with experimental data [M.T. Lee, R. Greif, C.P. Grigoropoulos, H.G. Park, F.K. Hsu, J. Power Sources Transport in, 166 (2007) 194–201] with a BASF F3-01(CuO/ZnO/Al₂O₃) catalyst. A correlation for the conversion efficiency of methanol has been obtained as a function of the operating temperature and a dimensionless time parameter which represents the ratio of the characteristic time of the methanol flow to the time for chemical reaction. The results show that for the constant wall temperature condition the steam reforming process of methanol results in a nearly uniform temperature throughout the microreactor over the range of operating conditions.     

Implications of sensor location in steam reformer temperature control

Hydrogen can be produced via steam reformation of many feedstocks. External heat sources provide the thermal energy required by the endothermic steam reformation reactions. Temperature control of the steam reformation reactor is critical to reactor performance and catalyst life. Closed-loop control systems are typically used to modulate the heat input rate based on a comparison between a set point temperature and a temperature measurement. The location of the temperature sensor relative to the heat input location is a choice made during reactor design that can have significant impact on reactor temperature control.     

Hydrogen production from solid sodium borohydride

A system for a controlled production of hydrogen from solid NaBH₄ has been designed and built. Cartridges of catalysed or non-catalysed NaBH₄ in powder form are fed by water or catalyst solution into a reactor; the reaction is started and tuned by controlling the input water (or water/catalyst solution) flow. We designed, built and tested different reactor layouts and geometries. Tests have been carried out in order to monitor operative parameters (i.e., water flow, reactor temperature) and to evaluate their influence on hydrolysis performance. The facility allows hydrogen flow in the 5–30 L/h range for several hours. The paper reports on the experimental runs and on the main achieved goals.     

Transient numerical modeling and model predictive control of an industrial-scale steam methane reforming reactor

A steam methane reforming reactor is a key equipment in hydrogen production, and numerical analysis and process control can provide a critical insight into its reforming mechanisms and flexible operation in real engineering applications. The present paper firstly studies the transport phenomena in an industrial-scale steam methane reforming reactor by transient numerical simulations. Wall effect and local non thermal equilibrium is considered in the simulations. A temperature profile of the tube outer wall is given by user defined functions integrated into the ANSYS FLUENT software. Dynamic simulations show that the species distribution is closely related to the temperature distribution which makes the temperature of the reactor tube wall an important factor for the hydrogen production of the reformer and the thermal conductivity of the catalyst network is crucial in the heat transfer in the reactor. Besides, there exists a delay of the reformer's hydrogen production when the temperature profile of the tube wall changes. Among inlet temperature, inlet mass flow rate and inlet steam-to-carbon (S/C) ratio, the mass flow rate is the most influencing factor for the hydrogen production. The dynamic matrix control (DMC) scheme is subsequently designed to manipulate the mole fraction of hydrogen of the outlet to the target value by setting the temperature profile trajectory of the reforming tube with time. The proportional-integral control strategy is also studied for comparison. The closed-loop simulation results show that the proposed DMC control strategy can reduce the overshoot and have a small change of the input variable. In addition, the disturbances of feed disturbance can also be well rejected to assure the tracking performance, indicating the superiority of the DMC controller. All the results give insight to the theoretical analysis and controller design of a steam methane reformer and demonstrate the potential of the CFD modeling in study the transport mechanism and the idea of combining CFD modeling with controller design for the real application.