Non-Thermal Plasma Assisted Reforming of Ethanol in Dynamic Plasma-Liquid Systems

The paper presents experimental and theoretical studies of non-thermal plasma assisted reforming of liquid ethanol into hydrogen-rich syngas in dynamic plasma-liquid systems （PLS） using electric DC and pulsed discharges in a gas channel with liquid wall （DGCLW） and DC discharge in a reverse vortex gas flow of Tornado type with ＂liquid＂ electrode （TORNADO-LE）. Results of experiments show the energy efficiency of plasma-chemical conversion of ethanol in studied systems. Results of model calculations explain the kinetic mechanism of non-equilibrium plasma-chemical transformations in different conditions. The proposed technique of plasma-fuel reforming can be used in alternative biofuels combustion technologies in advanced diesel engines and power plants.

Removal of CO from reformed fuels by selective methanation over Ni-B-Zr-O_δ catalysts

The Ni-B-Oδ and Ni-B-Zr-Oδ catalysts were prepared by the method of chemical reduction, and the deep removal of CO by selective methanation from the reformed fuels was performed over the as-prepared catalysts. The results showed that zirconium strongly influenced the activity and selectivity of the Ni-B-Zr-Oδ catalysts. Over the Ni-B-Oδ catalyst, the highest CO conversion obtained was only 24.32% under the experi-mental conditions studied. However, over the Ni-B-Zr-Oδ catalysts, the CO methanation conversion was higher than 90% when the temperature was increased to 220℃. Additionally, it was found that the Ni/B mole ratio also affected the performance of the Ni-B-Zr-Oδ catalysts. With the increase of the Ni/B mole ratio from 1.8 to 2.2, the CO methanation activity of the catalyst was improved. But when the Ni/B mole ratio was higher than 2.2, the performance of the catalyst for CO selective methanation decreased instead. Among all the catalysts, the Ni29B13Zr58Oδ catalyst investigated here exhibited the highest catalytic performance for the CO selective methanation, which was capable of reducing the CO outlet concentration to less than 40 ppm from the feed gases stream in the temperature range of 230-250℃, while the CO2 conversion was kept below 8% all along. Characterization of the Ni-B-Oδ and Ni-B-Zr-Oδ catalysts was provided by XRD, SEM, DSC, and XPS.

Mini-Stimulus to Fuel Reforms

At the present time, China is in need of economic stimulus, a fact testified to by the struggling branches of some banks and the sluggish manufacturing industry. Ye Tan. a financial commentator, said in a commentary published in the Shanghai-based NationalBusiness Daily. that the country should no longer base its optimistic mood solely on the explosive growth of the information technology （IT） and e-commerce industries. Without the upgrading of its manufacturing sector, China＇s economy will lose the foundation required to sustain its growth.

Experimental Investigation on Heat Transfer and Combustion of a Stirling Engine Combustor Fueled by Reformed Gas and Diesel Fuel

Thermochemical recuperation heat recovery is an advanced waste heat utilization technology that can effectively recover exhaust waste heat from oxy-fuel Stirling engines.The novel combustor of a Stirling engine with thermochemical recuperation heat recovery system is expected to utilize both reformed gas and diesel fuels as sources of combustion.In this research,the effects of various factors,including the H_(2)O addition,fuel distribution ratio(FDR),excess oxygen coefficient,and cyclone structure on the temperature distribution in the combustor,combustion emissions,and external combustion system efficiency of the Stirling engine were experimentally investigated.With the increase of steam-to-carbon ratio(S/C),the temperature difference between the upper and lower heating tubes reduces and the circumferential temperature fluctuation decreases,and the combustion of diesel and reformed gas remains close to complete combustion.At S/C=2,the external combustion efficiency is 80.6%,indicating a 1.6%decrease compared to conventional combustion.With the increase of FDR,the temperature uniformity of the heater tube is improved,and the CO and HC emissions decrease.However,the impact of the FDR on the maximum temperature difference and temperature fluctuation across the heater is insignificant.When the FDR rises from 21%to 38%,the external combustion efficiency increases from 87.4%to92.3%.The excess oxygen coefficient plays a secondary role in influencing temperature uniformity and temperature difference,and the reformed gas and diesel fuel can be burned efficiently at a low excess oxygen coefficient of 1.04.With an increase in the cyclone angle,the heater tube temperature increases,while the maximum temperature difference at the lower part decreases,and the temperature fluctuation increases.Simultaneously,the CO and HC emissions increase,and the external combustion efficiency experiences a decrease.A cyclone angle of 30°is found to be an appropriate value for achieving optimal mixing between reformed gas and diesel fuel.The research findings present valuable new insights that can be utilized to enhance the performance optimization of Stirling engines.

Thermochemical Recuperation for Stirling Engines by Diesel Steam Reforming: Thermodynamic Analysis

Thermochemical exhaust heat recovery is a prospective way to improve the thermal performance of Stirling engines. Based on Aspen HYSYS software, the simulation model of a Stirling engine combustor with a thermochemical recuperation(TCR) reformer was established to calculate the performance of the TCR system. The reforming temperature, fuel distribution ratio, steam-to-carbon ratio(S/C), and reforming pressure were changed to evaluate their effects on the reforming process and system efficiency. With increased reforming temperature, the equilibrium fuel conversion rate and heat recovery amount in the reformer gradually increase. The maximum combustor efficiency is achieved at the temperature of 600℃ and the fuel distribution ratio of 40%. With the S/C ratio increased from 1 to 2.5, the heat recovery rate and combustor efficiency increase significantly. The results show that the increase of fuel distribution ratio and S/C ratio leads to decreased reforming temperature, and external heat is needed to meet the heat balance for steam reforming. At a given reforming temperature and S/C ratio, increased reforming pressure results in decreased equilibrium fuel conversion rate and reforming reaction heat. At 5 MPa reforming pressure and 550℃ reforming temperature, the efficiency of the Stirling engine combustor is 92.7%, proving that the thermochemical recovery system can be applied to the Stirling engine under high pressure conditions.

Microfibrous entrapped ZnO-CaO/Al_2O_3 for high efficiency hydrogen production via methanol steam reforming

Sinter-locked microfibrous networks consisting of -3 vol.% of 8 p.m （dia.） nickel microfibers have been utilized to entrap -30vo1.% of 100-200 μm dia. porous AI203. ZnO and CaO were then highly dispersed onto the pore surface of entrapped A1203 by the incipient wetness impregnation method. Due to the unique combination of surface area, pore size/particle size, thermal conductivity, and void volume, the resulting microfibrous catalyst composites provided significant improvement of catalytic bed reactivity and utilization efficiency when used in methanol steam reforming. Roughly 260 mL/min of reformate, comprising 〉70% H2, 〈5% CO and trace CH4, with 〉97% methanol conversion, could be produced in a I cm3 bed volume of our novel microfihrous entrapped ZnO-CaO/Al2O3 catalyst composite at 470℃ with a high weight hourly space velocity （WHSV） of 15 h-1 using steam/methanol （1.3/1） mixture as feedstock. Compared to a packed bed of 100-200μm ZnO-CaO/Al2O3, our composite bed provided a doubling of the reactor throughput with a halving of catalyst usage.

High-Efficiency and Clean Combustion Natural Gas Engines for Vehicles

Natural gas engines have become increasingly important in transportation applications,especially in the commercial vehicle sector.With increasing demand for high efficiency and low emissions,new technologies must be explored to overcome the performance limitations of natural gas engines such as limits on lean or dilute combustion,unstable combustion,low burning velocity,and high emissions of CH_(4) and NO_(x).This paper reviews the progress of research on natural gas engines over recent decades,concentrating on ignition and combustion systems,mixture preparation,the development of different combustion modes,and after-treatment strategies.First,the features,advantages,and disadvantages of natural gas engines are introduced,following which the development of advanced ignition systems,organization of highly turbulent flows,and the preparation of high-reactivity mixtures in spark ignition engines are discussed with a focus on pre-chamber jet ignition,combustion chamber design,and H_(2)-enriched natural gas combustion.Third,the progress in natural gas dual-fuel engines is highlighted,including the exploration of new combustion modes,the development of novel pilot fuels,and the optimization of combustion control strategies.The fourth section discusses after-treatment systems for natural gas engines operating in different combustion modes.Finally,conclusions and future trends in the development of high-efficiency and clean combus-tion in natural gas engines are summarized.