燃气源控制气流非稳态耦合传热问题研究(Ⅰ)——计算模型和方法

针对某燃气源控制气流与导热套环之间的非稳态耦合传热问题,建立了数学模型,并采用整体求解的方法进行求解,即把流体区域的流动和对流换热与固体区域的导热过程组合起来,作为一个统一换热过程来处理。为确保计算结果在物理上的真实性,采用“假密度”法求解以温度T为求解变量的能量方程。对于非稳态控制方程离散后的离散方程采用了PISO方法进行求解。

伺服燃气源点火测试电路的高可靠设计

介绍了伺服燃气源的工作原理;针对伺服燃气源点火试验测试的要求与检测、点火流程设定的原则,以及伺服总成测控系统的测试原理,提出了伺服燃气源点火试验电路设计方法;分析了伺服燃气源点火试验时干扰的产生以及抑制的方法;并且通过合理的选用点火电源,达到电路的高可靠性设计;通过最终在点火试验中的应用证明了电路设计满足点火试验的要求。

引射器法LPG+AIR城镇管道燃气源清洁新工艺

研究用引射器法LPG+AIR城镇管道燃气源新工艺替代水平炉生产煤气,环境效益十分显著。经用综合质量指数法进行环境评价,结果表明,煤气厂及周围城区的环境综合质量从大于5级提高到3级水平。

PLC在多管新型燃气还原炉上的应用

2多管新型燃气还原炉是“八五”期间国家重点企业技术开发项目之一,经过近4年时间的研究、设计、制造和安装调试,已成功投入正常生产,是金属氧化物还原制取金属粉末的高效节能设备.多管新型燃气还原炉采用PLC实现了生产过程自动控制.它是根据生产工艺流程和电气控制逻辑,通过编程手段实现的,最终达到从推舟到卸舟,相应氢气阀门自动切换到还原过程的全部自动顺序步进控制,再次充分体现了PLC在生产过程自动控制中的优越性.

室外翅片管换热器的设计对空气源燃气机热泵系统性能的影响

研究了翅片管换热器的流路布置和支路数对空气源燃气机热泵系统性能的影响,研究结果表明:采用逆交叉流的流程布置方式空气源燃气机热泵的性能最好,而采用顺流的流程布置方式最差,与顺流相比,采用逆交叉流的流程布置方式空气源燃气机热泵性能提高了10%左右。翅片管换热器支路数采用14路比采用7路时空气源燃气机热泵性能提高了7%左右。因此,翅片管换热器的设计对空气源燃气机热泵系统性能有较大的影响,合理设计翅片管换热器对提高空气源燃气机热泵的性能起到了一定的作用。

TVD SCHEME WITH CHEMICAL REACTION FLOW AND ITS APPLICATION IN COMBUSTION GAS JETTING FLOW

By conjugating features of combustion gas jetting flows of the solid-rocket and using mathematical methods, a numerical scheme is systematically derived based on Harten′s standard TVD scheme, which fits for the flow with high temperature, pressure and velocity. The rational calculation formula of pressure partial derivation is also given out. By using the chemical kinetics knowledge, problems of multi-component and finite rate chemical reaction contained in combustion gas of the rocket flow field are discussed. The method for solving the mass source term of chemical reaction is clarified. Taking 9 reaction equations with 12 components as an example and utilizing the established calculation program, the free jetting flow field of the rocket is simulated. Numerical results show the correctness of the numerical scheme.

Effect of operating parameters on coal gasification

Coal combustion and gasification are the processes to utilize coal for production of electricity and many other applications. Global energy demand is increasing day by day. Coal is an abundant source of energy but not a reliable source as it results into high CO2 emissions. Energy industries are expected to decrease the CO2 emission to prevent global warming. Coal gasification is a process that reduces the CO2 emission and emerges as a clean coal technology. Coal gasification process is regulated by several operating parameters. A Number of investigations have been carried out in this direction. A critical review of the work done by several researchers in the field of coal gasification has been compiled in this paper. The effect of several operating parameters such as coal rank, temperature, pressure, porosity, reaction time and catalyst on gasification has been presented here.

Overview of Past, Present and Future Marine Power Plants

In efforts to overcome an foreseeable energy crisis predicated on limited oil and gas supplies, reserves; economic variations facing the world, and of course the environmental side effects of fossil fuels, an urgent need for energy sources that provide sustainable, safe and economic supplies for the world is imperative. The current fossil fuel energy system must be improved to ensure a better and cleaner transportation future for the world. Despite the fact that the marine transportation sector consumes only 5% of global petroleum production; it is responsible for 15% of the world NOx and SOx emissions. These figures must be the engine that powers the scientific research worldwide to develop new solutions for a very old energy problem. In this paper, the most effective types of marine power plants were discussed. The history of the development of each type was presented first and the technical aspects were discussed second. Also, the fuel ceils as a new type of power plants used in marine sector were briefed to give a complete overview of the past, present and future of the marine power plants development. Based on the increased worldwide concerns regarding harmful emissions, many researchers have introduced solutions to this problem, including the adoption of new cleaner fuels. This paper was guided using the same trend and by implementing the hydrogen as fuel for marine internal combustion engine, gas turbines, and fuel cells.

STUDY ON EVOLUTION REGULARITIES AND ABSORPTION CHARACTERISTICS OF SULFIDE DURING BITUMINOUS BRIQUETTE HORIZONTAL COMBUSTION

This paper discusses the evolution regularity and the absorption characters of sulfide for bituminous briquette burned in a horizontal burning fornace. The evolution rate of sulphur is affected by some factors, such as the sulphur content in the burning coal, burning time and the mean excess air coefficient in the furnace. With processing the experimental result, the calculation related expression has been obtained to predict the evolution rate of sulfide. The sulphur absorption efficiency of briquette is affected by tbe factors such as the character of the sulphur sorbent, the type of the coal and the operating parameters. By means of appropriately adjusting the calciumsulphur mole ratio, the mean excess air coefficient and the time-interval between pushing two layer briquettes, a high sulphur absorption efficiency (>74% ) can be obtained.

天津市东疆港某小区采暖工程设计

介绍了天津市东疆港某小区采暖工程设计过程,热源采用了燃气空气源吸收式热泵和燃气锅炉联合供热系统,充分发挥了二者的优势,在满足供热需求的前提下,实现了节能供热,并分析了联合供热系统作为热源的工程可行性与经济性,为该联合供热系统的推广利用提供了数据参考。

An Energy and Exergy Analysis of a Microturbine CHP System

The micro-turbine is known as a producer of high-grade energy （work） and also low energy （heat）. The following low grade heat energy have been modeled under ISO ambient conditions （international standard organization）, i.e. 15 ℃ and 1 bar, to utilize the waste heat energy of a 200 kW micro-turbine combined with a single effect absorption chiller, an organic ranking cycle using R245fa （ORC-R245 fa） as a working fluid, a multi-effect distillation desalination （MED） and a thermal vapor compression MED Desalination unit （TVC-MED）. The thermal comparison was carried out based on an energy and exergy analysis in terms of electric efficiency, exergetic efficiency, carbon footprint, and energy utilization factor （EUF）. The software package IPSEpro has been used to model and simulate the proposed power plants. As a result, utilizing the exhaust waste heat energy in single-effect absorption chillier has contributed to stabilize ambient temperature fluctuation, and gain the best exergetic efficiency of 39%, while the EUF has reached 72% and the carbon footprint was reduced by 75% in MED and TVC-MED Desalination respectively. The results also reveal that TVC-MED is more efficient than traditional MED as its gain output ratio （GOR） is improved by 5.5%. In addition, ORC-245fa generates an additional 20% of the micro-turbine electricity generation.

A 10kW-scale Distributed Power Plant of Natural Gas-Proton Exchange Membrane Fuel Cell

A 10 kW-scale natural gas fueled proton exchange membrane fuel cell(PEMFC) distributed power plant is presented in this paper,which is designed for cogeneration of power and heat. With homemade catalysts for CO removal in a two-stage methanation process and integrated reactor in the fuel processing system,the reformed fuel with CO molar fraction less than 10-5 is obtained for the fuel cell stack. Based on Matlab/Simulink/Stateflow and xPC Target platform,a rapid control prototype(RCP) is developed for real-time condition management,signal tracking and parameter tuning,data storing,and man-machine interaction. In a typical running with 4.3 kW stack power,the hydrogen production efficiency,gross power generation efficiency and heat recovery efficiency approach to 76%,41% and 50%,respectively. The peak stack power reaches 7.3 kW. Though there is still considerable dis-tance to long-term operation at 10 kW-scale net power generation,it is a milestone for the PEMFC-based stationary application in China.

Experimental Study on Combustion Characteristics of Unused Biomasses in Compact Combustor

The aim of the present study is to develop the biomass furnace combustor which can effectively employ four unused biomasses, i.e., wood bark, wood branch, bamboo, and grass as a fuel. Emphasis is placed on the combustion gas components and combustion gas temperature in the combustor. It is found from the study that： （1） Four unused biomasses can take plate self combustion and the stable combustion yield; （2） Different combustion temperature distribution appears in combustor and is affected by each biomass; （3） The concentrations of nitrogen oxide and sulfur oxides are lower than the discharge standard value; （4） Higher thermal efficiency yields for bark, bamboo and grass.

Global Evaluation of Energy in Hybrid M-HTFC/MGT Systems in Cogenerative Arrangement

This work concerns the study of HSs （Hybrid Systems） that are made up of the integration of M-HTFC （Medium and High Temperature Fuel Cell） and MGT （Micro-Gas-Turbine）. Different typologies of hybrid systems are taken into account, which differ from each other in their plant layouts. The plants are considered in cogenerative arrangement. The aim of this study is to carry out an energetic analysis of the HS considered to obtain an analytical expression to depict the system operating in cogenerative arrangement. An energetic comparison among the systems analyzed based on some indexes is effected, which allows an evaluation of the plants performances in cogenerative arrangement. An energetic analysis is carried out, which is based on a ＂black box＂ depiction of the plant in which the components and the mutual interactions are highlighted. The fuel cell component of the plant is not analyzed as a black box, but each element that constitutes it, is elaborated as a subsystem.

An Activity in Japan for Realizing CO2-Free Hydrogen Global Supply Chains

The current basic energy plan of Japan was authorized in the Cabinet in June 2010, in which ambitious energy and environmental targets and policies giving nuclear power a pivotal role toward 2030 were described. At present, the Japanese government has been forced to review the basic energy plan in the wake of the great east Japan earthquake occurred on March 11, 2011 followed by the severe accident at the nuclear power plants in Fukushima. Before the disaster, the IAE （institute of applied energy） had realized that it was not clear how CO2-free hydrogen would contribute to solving various energy and environmental issues, or that prospects were not clear for large demand of CQ-free hydrogen other than FCVs （fuel cell vehicles）. In this connection, the authors organized a voluntary ＂Concept Study Group （in short）＂ in March 2011 and held four meetings until the end of March 2012. Through the quantitative studies using IAE＇s simulation model （GRAPE）, the common recognition was built in the concept study group that hydrogen could contribute to energy security and increase in zero-emissions electric power ratio in Japan. It was also estimated that global CO2-free hydrogen supply chains could be realized by degrees after 2020. Based on these results, the authors made a proposal that hydrogen should be added in the primary energy constitution for new basic energy plan to the Japanese government because imported hydrogen could be considered as a pseudo-primary energy like LNG （liquefied natural gas）. Now, the succeeding ＂Action Plan Study Group （in short）＂ has been held focusing on hydrogen demand in various applications, future pictures of CO2-free hydrogen chains and road maps. Activity results of the ＂Concept Study Group＂ are shown here.

Combustion of Renewable Biogas Fuels

Biogas fuel is a sustainable and renewable fuel produced from anaerobic digestion of organic matter. The biogas fuel is a flammable mixture of methane and carbon dioxide with low to medium calorific values. Biogas is an alternative to conventional fossil fuels and can be used for beating, transportation and power generation. CFD （computational fluid dynamic） analysis of the combustion performance and emissions of biogas fuel in gas turbine engines is presented in this study. The main objective of this study is to understand the impact of the variability in the biogas fuel compositions and lower heating values on the combustion process. Natural gas, biogas from anaerobic digester, landfill biogas, and natural gas/biogas mixture fuels combustion were investigated in this study. The CFD results show lower peak flame temperature and CO mole fractions inside the combustor and lower NOx emissions at the combustor exit for the biogas compared to natural gas fuel. The peak flame temperature decreases by 37% for the biogas landfill （COJCH4 = 0.89） and by 22% for the biogas anaerobic digester （CO2/CH4 = 0.54） compared to natural gas fuel combustion. The peak CO mole fraction inside the combustor decreases from 9.8 × 10-2 for natural gas fuel to 2.22 × 10-4 for biogas anaerobic digester and 1.32 × 10-7 for biogas landfill. The average NOx mole fraction at the combustor exit decreases from 1.13 × 10-5 for natural gas fuel to 0.40 × 10-6 for biogas anaerobic digester and 1.06 × 10-6 for biogas landfill. The presence of non-combustible constituents in the biogas reduces the temperature of the flame and consequently the NOx emissions.

Potentialities of Renewable Energy in Victoria, Australia

In utility power system, electricity demand is being covered largely by fossil fueled power generation, which contributes high level of GHG （greenhouse gas） emission and causes global warming worldwide. In order to reduce GHG emission level, most of the countries in the world targeting towards green energy that is power generation from RE （renewable energy） sources. In this paper, it is considered to study prospects of RE sources in particular, solar and wind in Victoria State which are abundant as compared to other sources of renewable. The wind and solar energy feasibility study and sensitivity analysis has been done for Victoria with the aid of HOMER （hybrid optimization model of electric renewable） simulation software. From the study, it has clearly evicted that wind energy combinational HPS （hybrid power system） has more contribution, and high potential than solar PV （photovoltaic） systems for a particular location. This study also investigates the influences of energy storage in the proposed HPS.

A Comparison between Fossil and Nuclear Power Plants Pollutions and Their Environmental Effects

New researches on serious public health problems such as respiratory disease, heart attacks, and premature deaths, show the threat of air and environmental pollution on human＇s health. Exhausting greenhouse gases for electrical energy production in fossil fueled power plants is one of the major reasons of environmental pollutions. Increasing energy demand has made global concerns about the environmental pollutions of fossil power plants. In this article, fossil power plant productive pollutants such as Sulfur Dioxide, Mercury, and Carbon Dioxide, are investigated. On the other hand, nuclear power plant and its produced waste are discussed as the future power generation source. In this article, fossil and nuclear power plants are compared as power sources, pollutants, and their environmental effects. First, investigations are made on fossil power plants and their effects on environment and climate changes. On the other hand, nuclear power plants are discussed as a possible replacement for fossil power plants. In this part, effects of radiation on human health and environment like important nuclear accidents are investigated. This paper summarizes several types of power plants and it is deduced that the nuclear power plant is more clean energy producer in comparison to other power plants.

燃气远程抄表系统的合理实现

分析现有燃气表远程集抄系统及其优缺点,提出一种新型燃气表远程集抄系统,探讨了其组成、通信方式以及系统中关键设备(集中器和采集器)的实现。

Performance of a Double Catalyst Fuel Cell Cathode with a Tubular Oxygen Breathing and Preliminary Reduction Zone

This paper discusses a mathematical model for a liquid phase reacting flow occurring at the cathode of a patent pending novel fuel cell geometry, where a non homogeneous catalysis carried by gold and Prussian Blue, with the first reducing air O2 and the second the resulting H2O2. The breathing zone is porous walls microtubes, with three different types of pores in its walls. Inside the microtubes there is water solution of sulfuric acid. The microtubes possess an external layer of extremely porous polymer hydrophobic agent. A Prussian Blue thin porous layer is over the selective membrane. Appropriate porous and tubular connecting elements close the fluid loop. The asymmetry induces proper current and electric potential profiles, which leads to a mainly electrocapillary electrokinetic flow, which enhances the oxygen transport and assures the H2O2 flow to its reduction layer.