新型太阳能光伏光热一体化系统性能实验研究

文章提出了一种新型热管式太阳能光伏光热(PV/T)一体化系统,并提出了能够表征主动式PV/T系统能量收益的参数—实际能量收益率。在同一工况下,对热管式PV/T系统和PV系统进行测试研究,分析不同影响因素对热管式PV/T系统光电转化效率、光热转化效率及实际能量收益率的影响规律。研究结果表明:当热管式PV/T系统的循环流量为320 L/h时,该系统的实际能量收益率最大;同一工质流量下,光热转化效率对热管式PV/T系统实际能量收益率的影响远大于光电转化效率;热管式PV/T系统的实际能量收益率比PV系统高29.09%。     

铁电晶体热电转化回热循环的性能优化准则

考虑铁电晶体热电能量转化回热循环的有限时间性以及热阻和铁电介质的损耗等不可逆因素，定义回热循环能量转化的特征参量λ，对循环性能进行优化研究，给出铁电晶体热电转化最大输出功率状态下的优化准则以及功率与效率协调的优化准则，为回热式电晶体热电能量转化装置的优化设计提供理论依据。』     

叶顶间隙形状对Wells透平性能的影响

Wells透平对叶顶间隙的改变十分敏感,合理改造Wells透平的叶顶间隙有助于提高其能量转换效率。本文利用CFD技术在控制叶顶间隙大小相等的前提下研究了三种具有不同类型叶顶间隙形状的Wells透平,比较其出力、高效运行区和能量转化效率,考察其性能上的差异和适用范围,通过对流场和压场的分析找出其性能差异的根本原因。结果表明：渐扩型叶顶间隙的Wells透平具有较高的能量转化效率,但容易失速;均匀叶顶间隙的Wells透平具有最大的出力且高效运行区更宽;相较于前面两者,渐缩型叶顶间隙的Wells透平性能不突出。     

固体氧化物燃料电池简介

1技术特征与传统的火力发电技术不同,燃料电池是通过电化学反应方式将燃料中的化学能直接转化为电能的发电装置。由于不经过高温燃烧,是化学能转变为热能的过程,不受卡诺循环效率的制约,所以燃料电池的能量转化效率非常高。单位发电量所需燃料     

钒电池电解液配比的优化及其对电池性能的影响

电解液是钒电池能量存储的核心,其组成对电池的能量转化效率、循环稳定性等具有显著影响。本工作针对正负极电解液体积比、电解液价态,较系统地考察了它们对钒电池电化学性能的影响规律。结果表明,保持正极电解液体积不变,单纯增加负极的体积,可提高电池的放电容量,但对电池的能量转换效率影响较小;电解液价态的升高会在一定程度上降低钒电池的放电容量,但其能量转换效率却呈现先升高后降低的抛物线规律;增加负极电解液体积和提高电解液价态均会导致负极活性物质过量,但后者对电池性能的影响更为显著,在后者的基础上前者对能量转换效率的影响也会被放大。     

JL465Q5发动机点火线圈特性研究

针对JL465Q5发动机,以ATmega8单片机为核心,成功开发出一套应用天然气的电控点火系统,该系统已在发动机台架试验中成功应用。为了优化发动机的燃烧过程,对点火能量进行了测试。试验采用改变点火线圈的初级回路的闭合时间,测试点火线圈的初级断开电流、次级输出电压和电流,计算出点火线圈的初级储能、次级输出能量以及点火线圈的能量转化效率。试验结果表明,点火线圈的初级储能在闭合时间为6ms时接近饱和,继续增大闭合时间,初级线圈储能和次级输出能量都不再继续增大;随着闭合时间的增长,点火线圈的能量转化效率不断下降。     

JIA65Q5发动机点火线圈特性研究

针对JIA65Q5发动机,以ATmega8单片机为核心,成功开发出一套应用天然气的电控点火系统,该系统已在发动机台架试验中成功应用.为了优化发动机的燃烧过程,对点火能量进行了测试.试验采用改变点火线圈的初级回路的闭合时间,测试点火线圈的初级断开电流、次级输出电压和电流,计算出点火线圈的初级储能、次级输出能量以及点火线圈的能量转化效率.试验结果表明,点火线圈的初级储能在闭合时间为6ms时接近饱和,继续增大闭合时间,初级线圈储能和次级输出能量都不再继续增大;随着闭合时间的增长,点火线圈的能量转化效率不断下降.     

摆式振荡水翼的水动力性能分析

基于传统振荡水翼运动模型提出一种适用于垂直轴振荡水翼潮流能发电装置的摆式运动模型,并建立相应的数学模型。利用流体动力学软件Fluent软件建立该运动模型的网格模型,分析翼型NACA0015在不同运动参数下的水动力性能及能量捕获效率,并从水翼在运动过程中攻角的变化和漩涡结构方面分析振荡频率和俯仰振幅对水翼水动力性能的影响。结果表明,在小的振荡频率下,水翼的升沉振幅是影响能量提取效率的主要因素,随着频率的增加,升沉振幅对能量提取效率的影响减弱;在较大的频率下,俯仰振幅对水翼能量提取效率的影响更为明显。在适当的运动参数下,水流动能转化为水翼动能的效率可达30%。     

氢气在微燃烧器内的能源转化

采用MATLAB程序建立了带有余热回收的微燃烧器的一维数值模型,计算了TPV(thermo-photovoltaic)系统中化学能转化为电能的能量转化效率。探讨微燃烧器中氢气在空气和纯氧条件下的燃烧特性,研究了当量比、内管直径、进气速度和传热系数对微燃烧器燃烧性能的影响。结果表明,当当量比为1时,氢气在纯氧下的淬火直径(0.065 mm)比在空气中(0.1 mm)小;当当量比为1,内管直径为0.5 mm时,在TPV系统中,氢气在纯氧下的能量转化效率(6.3%)比在空气中(1.6%)高。     

Optimization of the electrolyte ratio for the vanadium flow battery and its effect on the battery performance

电解液是钒电池能量存储的核心,其组成对电池的能量转化效率、循环稳定性等具有显著影响。本工作针对正负极电解液体积比、电解液价态,较系统地考察了它们对钒电池电化学性能的影响规律。结果表明,保持正极电解液体积不变,单纯增加负极的体积,可提高电池的放电容量,但对电池的能量转换效率影响较小;电解液价态的升高会在一定程度上降低钒电池的放电容量,但其能量转换效率却呈现先升高后降低的抛物线规律;增加负极电解液体积和提高电解液价态均会导致负极活性物质过量,但后者对电池性能的影响更为显著,在后者的基础上前者对能量转换效率的影响也会被放大。     

太阳能驱动生物质气化多联产系统研究

提出一种太阳能驱动生物质气化的动力多联产系统,利用聚光太阳能驱动生物质热化学气化反应,生成的合成气在合成反应单元中被转化为天然气,未反应的合成气直接用于联合循环系统发电.该文对系统进行热力学性能分析,探究了气化温度和水煤气转换单元对系统性能的影响.结果表明系统的一次能源效率为44.63％,产物中合成天然气和发电量之比为...     

煤的部分空气气化联合循环发电系统特性研究

煤的部分空气气化联合循环发电是一种把煤气化技术和循环流化床技术结合起来的洁净煤发电技术。文章通过对三种方案的计算，得出了碳的转化率与运行温度、煤气热值、气化效率、系统效率之间的关系，证实了碳的转化率对系统运行有重要的影响，同时和其他气化方式下联合循环发电系统进行比较分析，证实煤的空气部分气化联合循环系统是一高效低污染、技术简单、投资小、见效快的发电系统。     

The Development of Coke Carried—Heat Gasification Coal—Fired Combined Cycle

INTRODUCTIONCoal is the main energy resource in China. Morethan 70% electric power is generated by coal-firedpower plants in the country. It will be continued to bedominant in next century. The need for new electricgenerating capacity is growing along with the growthof Chinese economy. Meanwhile, environment pollution caused by coal combustion is also concerned here.So, searching new technologies to burn coal cleanlyand efficiently to produce power is a very importanttask to the energy r…     

Simulation of a new biomass integrated gasification combined cycle (BIGCC) power generation system using Aspen Plus: Performance analysis and energetic assessment

A new biomass integrated gasification combined cycle (BIGCC), which featured an innovative two-stage enriched air gasification system coupling a fluidized bed with a swirl-melting furnace, was proposed and built for clean and efficient biomass utilization. The performance of biomass gasification and power generation under various operating conditions was assessed using a comprehensive Aspen Plus model for system optimization. The model was validated by pilot-scale experimental data and gas turbine regulations, showing good agreement. Parameters including oxygen percentage of enriched air (OP), gasification temperature, excess air ratio and compressor pressure ratio were studied for BIGCC optimization. Results showed that increase OP could effectively improve syngas quality and two-stage gasification efficiency, enhancing the gas turbine inlet and outlet temperature. The maximum BIGCC fuel utilization efficiency could be obtained at OP of 40%. Increasing gasification temperature showed a negative effect on the two-stage gasification performance. For efficient BIGCC operation, the excess air ratio should be below 3.5 to maintain a designed gas turbine inlet temperature. Modest increase of compressor pressure ratio favored the power generation. Finally, the BIGCC energy analysis further proved the rationality of system design and sufficient utilization of biomass energy.     

Innovative concept for gasification for hydrogen based on the heat integration between water gas shift unit and coal–water–slurry gasification unit

In order to achieve the energy cascade utilization and improve the energy utilization efficiency of coal–water–slurry (CWS) gasification for hydrogen system, the heat integration scheme (HIS) between the water gas shift unit and the gasification unit is put forward. The effects of temperature change of CWS and oxygen on the gasification performance are investigated. Both the HIS and the non-heat integration scheme (NHIS) are analyzed by using gasification performance, energy conversion efficiency and exergy efficiency. The results show that the specific coal consumption and the specific oxygen consumption decrease by 2.7% and 6.5%, respectively, as the feedstock is preheated up to the temperature of 150 °C. The energy conversion efficiency of HIS and NHIS are nearly the same. The exergy efficiency of HIS (62.66%) is better than that of NHIS (62.02%). Therefore, the HIS is better than the NHIS by heat integration between the WGS unit and the gasification unit.     

4MW级生物质气化发电示范工程的设计研究

介绍了我国4MW级的生物质气化整体联合循环发电示范工程的设计特点。该工艺中使用了中温静电除尘、焦油裂解装置和显热回收系统，预计投运后，将会使生物质的气化效率提高、可燃气中焦油含量减少以及系统效率得以提高，为我国生物质能的开发与运用开辟了广阔的前景。     

An experimental study on air gasification of biomass micron fuel (BMF) in a cyclone gasifier

Biomass micron fuel (BMF) produced from feedstock (energy crops, agricultural wastes, forestry residues and so on) through an efficient crushing process is a kind of powdery biomass fuel with particle size of less than 250 μm. Based on the properties of BMF, a cyclone gasifier concept has been considered in our laboratory for biomass gasification. The concept combines and integrates partial oxidation, fast pyrolysis, gasification, and tar cracking, as well as a shift reaction, with the purpose of producing a high quality of gas. In this paper, characteristics of BMF air gasification were studied in the gasifier. Without outer heat energy input, the whole process is supplied with energy produced by partial combustion of BMF in the gasifier using a hypostoichiometric amount of air. The effects of equivalence ratio (ER) and biomass particle size on gasification temperature, gas composition, gas yield, low-heating value (LHV), carbon conversion and gasification efficiency were studied. The results showed that higher ER led to higher gasification temperature and contributed to high H₂-content, but too high ER lowered fuel gas content and degraded fuel gas quality. A smaller particle was more favorable for higher gas yield, LHV, carbon conversion and gasification efficiency. And the BMF air gasification in the cyclone gasifier with the energy self-sufficiency is reliable.     

Hybrid clean energy technologies for power generation from sub-bituminous coals: a case of 250 MW unit

Major re-thinking is required on the conventional pulverized fuel conversion route of power generation wherein the ash and mineral burden in coals is transported through the entire flow passage of the boiler. For high-ash fuels, this has to be contained and the boiler must be clear of all mineral matter. The two independent clean coal candidate technologies for efficiency enhancement and emission controls – ultra-supercritical cycle (USC) and integrated gasification with combined cycle (IGCC) – both have limitations in adaptation to high-ash coals. While the USC is limited by the steam temperature up to 600°C (commercial scale) (700°C pilot scale) and boiler tube failure risks, IGCC is limited to high-quality fuels like diesel, naphtha, etc. (commercial scale) and high-grade coals (pre-commercial scale). The hybridization of the two technologies in their current form (ultra-supercritical cycle with gasification conversion) and carbon capture and storage (CCS) together with solar energy (solar thermal and solar photovoltaic) integration presents possibilities for immediate application to low-grade sub-bituminous coals to achieve the clean technology goals. The energy efficiency of the hybrid system is around 44.45%, which is of the order of the USC with pulverized coal combustion. But the predominant benefits of a clean operation override. The benefits are reduction in CO₂ generation from 0.86 to 0.70 kg/kWh and reduction in ash expelled from 0.20–0.24 to 0.12–0.18 kg/kWh besides elimination of dispersion of ash around the power station and facilitating CCS.     

Bench-scale bubbling fluidized bed systems around the world - Bed agglomeration and collapse: A comprehensive review

Thermochemical conversion by gasification process is one of the most relevant technologies for energy recovery from solid fuel, with an energy conversion efficiency better than other alternatives like combustion and pyrolysis. Nevertheless, the most common technology used in the last decades for thermochemical conversion of solid fuel through gasification process, such as coal, agriculture residues or biomass residues are the fluidized bed or bubbling fluidized bed system. For these gasification technologies, an inert bed material is fed into reactor to improve the homogenization of the particles mixture and increase the heat transfer between solid fuel particles and the bed material. The fluidized bed reactors usually operate at isothermal bed temperatures in the range of 700–1000 °C, providing a suitable contact between solid and gas phases. In this way, chemical reactions with high conversion yield, as well as an intense circulation and mixing of the solid particles are encouraged. Moreover, a high gasification temperature favours carbon conversion efficiency, increasing the syngas production and energy performance of the gasifier. However, the risk of eutectic mixtures formation and its subsequent melting process are increased, and hence the probability of bed agglomeration and the system collapse could be increased, mainly when alkali and alkaline earth metals-rich biomasses are considered. Generally, bed agglomeration occurs when biomass-derived ash reacts with bed material, and the lower melting temperature of ash components promotes the formation of highly viscous layers, which encourages the progressive agglomerates creation, and consequently, the bed collapse and system de-fluidization. Taking into account the relevance of this topic to ensure the normal gasification process operating, this paper provides several aspects about bed agglomeration, mostly for biomass gasification systems. In this way, chemistry and mechanism of bed agglomeration, as well as, some methods for in-situ detection and prediction of the bed agglomeration phenomenon are reviewed and discussed.     

Experimental evaluation of a 35 kVA downdraft gasifier

Energy conversion systems based on biomass are particularly interesting because biomass utilization effectively closes the carbon cycle besides achieving self-sustainability. Biomass is particularly useful for highly populated and agriculture dependent economic nations like China and India. A compact and cost effective downdraft gasification system was developed. The present paper describes an experimental investigation on a biomass based gasifier engine system with a capacity of 35 kVA for power generation application. The problem of cooling and cleaning the hot and dirty gas from the gasifier has been satisfactorily solved by the effective cooling and filtration system. The gasifier developed is observed to be operation friendly. The quality of gas was evaluated in terms of its composition, conversion efficiency and total particulate matter. The maximum output of the power plant was obtained at the combustion zone temperature of 850oC. The experimental investigations showed that the percentage reduction in total particulate matter is 89.32%. The conversion efficiency of the biomass gasifier is found to be dependent on the operation conditions and fuel properties of the gasifier. The optimum value of equivalence ratio was observed to be 0.3134 for achieving the maximum gas conversion efficiency of the present gasifier configuration.