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...     

新产品

太阳能反应器将可循环利用二氧化碳 美国国家实验室开发了一种新型太阳能反应器,可将二氧化碳分解为一氧化碳和氧气,或将水分解为氢气和氧气.这项被称之为"阳光变石油"项目的最终目标是循环利用被封存的CO2,并将CO产品与H2合成液体燃料.     

一种基于太阳能供能的CCRs捕捉CO_2方案研究

文章提出一种基于太阳能供能的的CCRs火电厂CO2回收系统,该系统将高温太阳能集热技术和钙基吸收剂循环煅烧/碳酸化法（CCRs）进行耦合。以目前国内外研究的塔式太阳能集热器以及双流化床反应器为基础,提出一种基于太阳能供能的CCRs捕捉火电厂CO2方案,并对其可行性进行初步分析,最后指出了该方案需进一步解决和研究的问题。     

生物质气流床气化制取合成气的试验研究

利用一套小型生物质层流气流床气化系统,研究了稻壳、红松、水曲柳和樟木松4种生物质在不同反应温度、氧气/生物质比率(O/B)、水蒸汽/生物质比率(S/B)以及停留时间下对合成气成分、碳转化率、H2/CO以及CO/CO2比率的影响.研究表明4种生物质在常压气流床气化生成合成气最佳O/B范围为0.2～0.3(气化温度.1300℃),高温气化时合成气中CH4含量很低,停留时间为1.6s时其气化反应基本完毕.加大水蒸汽含量可增加H2/CO比率,在S/B为0.8时H2/CO比率都在1以上,但水蒸汽的过多引入会影响煤气产率.气化温度是生物质气流床气化最重要的影响因素之一.     

新型近零排放煤气化燃烧利用系统

以CO2接受体法气化技术为基础构建了新型的近零排放煤气化燃烧利用系统。煤被加入压力循环流化床气化炉里以水蒸汽为气化介质进行部分气化产生H2、CO和CO2在以CaO作为接受体吸收CO2并放出气化反应所需的热量的同时，CO也通过水煤气变换反应被转化。气化过程所产生高纯度氢气供给固体氧化物燃料电池发电。煤经部分气化后所剩的低活性焦碳和吸收CO2后产生的CaCO2一起被送入循环流化床燃烧炉，焦炭和燃料电池所排出的舍氢尾气燃烧提供CaCO2分解所需的热量。燃烧炉产生的高浓度CO2与其他污染物(SOk、NOx等)一起经余热发电后综合处理，从而实现整个系统的近零污染物排放。经计算，以烟煤为燃料的系统发电效率可达65．5％左右。     

煤/石油焦共气化过程中AAEM的催化转化行为

以富含碱金属及碱土金属的准东煤和石油焦为原料,在热重反应器上分别进行了水蒸气及CO2条件下的共气化实验,探究了AAEM的赋存形态对其转化行为及燃料气化特性的影响规律.研究表明,准东煤与石油焦在水蒸气条件下的共气化反应速率明显快于CO2条件,来自煤中的AAEM促进了石油焦的气化.在CO2气氛中,不同赋存形态矿物的催化作用存在较大差异,盐酸溶态的Ca起主要催化作用,并在气化过程中生成CaS.而在水蒸气气氛中,不同赋存形态矿物的催化作用差异较小,气化过程中含Ca组分主要生成CaO.     

秸秆发电

秸秆是一种很好的清洁可再生能源,是最具开发利用潜力的新能源之一,具有较好的经济、生态和社会效益。在生物质再生利用过程中,排放的CO2与生物质再生时吸收的CO2达到碳平衡,具有CO2零排放作用,对缓解和最终解决温室效应问题具有潜在贡献价值。 秸秆发电,就是以农作物秸秆为主要燃料的一种发电方式,又分为秸秆气化发电和秸秆燃烧发电。秸秆气化发电是将秸秆在缺氧状态下燃烧,发生化学反应,生成高品位、易输送、利用效率高的气体,利用这些产生的气体再进行发电。但秸秆气化发电工艺过程复杂,难以适应大规模应用,主要用于较小规模发电项目。秸秆直接燃烧发电是21世纪初期实现规模化应用唯一现实的途径。     

高温快速加热条件下压力对煤气化反应特性的影响

建立了一套能同时实现高温高压和快速加热的实验设备和研究方法,使煤气化反应动力学基础研究能在与实际气流床煤气化炉相近的条件下进行.研究表明,当CO2体积分数相同时,最大CO生成速度随压力的升高而升高;煤焦的气化反应速度随全压的升高而升高.即使全压和CO2体积分数不同,只要CO2的分压、温度等其他条件相同,煤焦的气化反应速度就基本上一致.说明全压和CO2体积分数对煤焦气化反应速度的影响可以归纳为CO2分压的影响.高温快速加热条件下,除了温度以外,CO2分压是影响煤气化特性的重要因素.     

基于铁矿石载氧体25 kWth串行流化床生物质化学链气化实验研究

设计并建立了25kW_(th)串行流化床生物质气化反应器,基于此反应器,以赤铁矿石作为载氧体,开展生物质化学链气化实验研究,考察气化反应器温度、S/B、载氧体添加比例对生物质气化特性的影响。当赤铁矿占床料比例高于40%时,该气化装置的气化反应器温度保持平稳,铁矿石载氧体的再生及传热性能优良。燃料反应器出口烟气的成分为H_2、CO_2、CO、CH_4和少量的C_2H_4。随着气化反应器温度升高,气化反应器出口烟气中CO、CH_4和C_2H_4体积分数逐渐降低,相应的CO_2体积分数逐渐升高。随着S/B由0.6升高到1.4,气化反应器出口烟气中H_2和CO_2体积分数逐渐升高,CO、CH_4和C_2H_4体积分数逐渐降低。另外,载氧体添加比例增加,生物质气化反应器出口烟气中CO、H_2、CH_4和C_2H_4体积分数呈减小的趋势,而CO_2体积分数显著增加。     

CO2气氛下生物质气化制氢的数值分析

生物质气化制氢有重要的工业应用价值,本文采用ASPEN PLUS软件数值模拟了稻壳在流化床中的气化过程。本次模拟运用吉布斯自由能最小化原理,选择RGibbs和RYield模块,采用CO2作为气化剂,计算获得了气化温度、CO2质量流量、CO2和稻壳质量比和碳转化率对产氢率的影响规律。结果表明：在CO2质量流量为200kg/h时,H2的生成率高达43%。随着CO2/B增加,CO和CO2体积分数逐渐升高,CH4体积分数下降,H2体积分数在不同的气化温度下趋于平稳（600~700℃）或下降（800~1000℃）。随着气化温度升高,碳转化率增加;随着CO2和稻壳质量比的升高,碳转化率下降。     

石油焦水煤浆在新型气化炉内气化过程的数值计算

对石油焦水煤浆(PCCWS)在多喷嘴新型水煤浆气化炉内的气化过程进行了数值计算,考察了气化炉内的温度分布、各种气化产物浓度分布规律.结果表明:同浓度的石油焦水煤浆气化与普通水煤浆气化相比,气化炉内平均温度略有上升,碳转化率提高,气化炉出口粗煤气中有效气(CO H2)含量提高7.91%,CO2和H2O浓度大幅下降,水分解率大大提高;石油焦水煤浆气化可以节约氧气约6%,气化效果明显优于普通水煤浆.     

以甲烷重整方式利用气化煤气显热的甲醇-电多联产系统

根据"温度对口,组分合适"的原则,提出了一种以甲烷重整来利用煤气显热的多联产系统,可用于煤/天然气、煤/焦炉煤气双燃料系统.该系统利用气化炉出口的高温煤气显热作为甲烷/水蒸汽重整的反应热,把煤气的热能转变为合成气的化学能进行回收,使天然气和焦炉煤气重整后的富氢气体与富碳的气化煤气可按化工生产要求灵活调配.计算结果表明,相比于单产系统,双燃料系统效率最少可提高约1.5%.     

Assessment of an integrated active solar and air-source heat pump water heating system operated within a passive house in a cold climate zone

In the pursuit of energy savings and emission reductions, solar energy heating systems have been promoted in China. However, there still exist many barriers to the operation of solar heating systems, in combination with other systems, under realistic conditions. In order to investigate this further, an integrated space heating system including passive sunspace, active solar water heating, and air-source heat pump (ASHP) was built. The detailed running performance of each subsystem was comparatively analyzed in a full-scale test house in a cold climate zone. This integrated system showed many encouraging results in terms of the maintenance of a stable and comfortable indoor thermal environment during the winter season. The study building consumed electricity as convectional energy, which only accounted for about one-third of the total energy supplied for heating. However, our study also found some shortcomings in the system design. Feasible suggestions regarding the running procedures aimed at a more optimal and effective design were proposed. The systems proposed in this study could be used as a promising future technology for energy savings and emission reductions in rural buildings. The study could also help achieve targets for energy savings and renewable energy utilization in China and other countries.     

太阳能、热泵辅助燃气供热系统实验研究

搭建了太阳能、热泵辅助燃气的供热系统测试平台,对太阳能辅助燃气供热系统、热泵辅助燃气供热系统以及太阳能、热泵辅助燃气供热系统的热性能进行测试,并对三种供热系统的经济环境效益进行分析.试验结果表明,试验条件下,三种供热系统的修正后一次能源利用率分别为93.3％、92.8％、103.9％,与燃气供热系统相比,节能率分别为3...     

Optimization and performance prediction of a new near-zero emission coal utilization system with combined gasification and combustion

In accordance with the new near-zero emission coal utilization system with combined gasification and combustion, which is based on the CO₂ acceptor gasification process, the product gas composition of the gasifier and the combustor was calculated by means of thermodynamic equilibrium calculation software FactSage 5.2. Based on these calculations, the whole system efficiency calculation method that complies with the mass and energy conservation principle was established. To enhance the system efficiency, the system pressure and the gasifier carbon conversion ratio were optimized. The results indicate that the system efficiency increases with increasing pressure and gasifier carbon conversion ratio. After taking into consideration the influence of the pressure and carbon conversion ratio on the performance of the system, the gasifier and the combustor were synthetically studied. The optimum system pressure and carbon conversion ratio were obtained as 2.5 MPa and 0.7, respectively. The system efficiency could reach around 62.1% when operated in these two optimum parameters. If the advanced ion transport membrane (ITM) air separation technology is used, there would be an increase of another 1.3%. Translated from Proceedings of the CSEE, 2006, 26(9): 7–13 [译自: 中国电机工程学报]     

Hydrogen production from fossil fuels with carbon capture and storage based on chemical looping systems

This paper analyzes innovative processes for producing hydrogen from fossil fuels conversion (natural gas, coal, lignite) based on chemical looping techniques, allowing intrinsic CO₂ capture. This paper evaluates in details the iron-based chemical looping system used for hydrogen production in conjunction with natural gas and syngas produced from coal and lignite gasification. The paper assesses the potential applications of natural gas and syngas chemical looping combustion systems to generate hydrogen. Investigated plant concepts with natural gas and syngas-based chemical looping method produce 500 MW hydrogen (based on lower heating value) covering ancillary power consumption with an almost total decarbonisation rate of the fossil fuels used.The paper presents in details the plant concepts and the methodology used to evaluate the performances using critical design factors like: gasifier feeding system (various fuel transport gases), heat and power integration analysis, potential ways to increase the overall energy efficiency (e.g. steam integration of chemical looping unit into the combined cycle), hydrogen and carbon dioxide quality specifications considering the use of hydrogen in transport (fuel cells) and carbon dioxide storage in geological formation or used for EOR.     

A downdraft high temperature steam-only solar gasifier of biomass char: A modelling study

A numerical model of a solar downdraft gasifier of biomass char (biochar) with steam based on the systems kinetics is developed. The model calculates the dynamic and steady state profiles, predicting the temperature and concentration profiles of gas and solid phases, based on the mass and heat balances. The Rosseland equation is used to calculate the radiative transfer within the bed. The char reactivity factor (CFR) is taken into account with an exponential variation. The bed heating dynamics as well as the steam velocity effects are tested. The model results are compared with different experimental results from a solar packed bed gasifier, and the temperature profile is compared to an experimental downdraft gasifier. Hydrogen is the principal product followed by carbon monoxide, the carbon dioxide production is small and the methane production is negligible, indicating a high quality syngas production. By applying the temperature gradient theory in the steam-only gasification process for a solar gasifier design, a solar downdraft gasifier improves the energy conversion efficiency by over 20% when compared to a solar packed bed gasifier. The model predictions are in good agreement with the experimental results found in the literature.     

Integrated characteristics and performance of zero emission coal system

Before the commercialization of zero emission coal (ZEC), some technical hurdles must be settled and the performance of the whole system needs to be studied. The main technical hurdles of ZEC system are analyzed and some solutions are presented in this paper. A detailed ZEC system is setup and its characteristics are studied. High temperature solid oxide fuel cell (SOFC) is used to produce electricity and served as the heat source for the decarbonater. ZnO and NaHCO₃ are proposed to deeply eliminate H₂S and HCl. H₂ recycle ratio should be kept at 0.75 for the high conversion ratio of carbon in the gasifier and the high system efficiency. Calcium to carbon mole ratio (CTCR) should be kept around 0.6 to reach high CO₂ sequestration rate and acceptable economic penalty. Fuel utilization factor (U_f) of SOFC should be kept around 0.55 so as to supply enough heat to the decarbonater, and steam to carbon ratio (STCR) for the reformers in the system should be kept around 2.0. With these optimized parameters, the total efficiency of the system of 69.1% and the CO₂ sequestration ratio of 87% can be reached.     

燃煤发电排放CO2的处置利用途径

CO2是能源与环境生物活动循环的依存产物,工业化后煤炭等化石燃料的使用产生了大量的CO2排放,打破了CO2的自然生态平衡。介绍了CO2的来源,分析了燃煤发电CO2的排放量,我国每年燃煤发电约排放C0230．7×10^8t,指出燃煤发电是减排CO2的重点。提出CO2的利用与处置的方法主要有：CO2和合成氨加工成尿素,并发展大颗粒尿素促进造林绿化;美国正在建的CO2零排放燃煤发电装置,采用了CO2收集与封存（CCS）技术,以及煤制油清洁燃料联产电力。     

Net energy analyses of four technologies to provide residential space heat

After having calculated energy ratios for four methods of providing residential space heat, passive solar heating systems were found to return approx. 20–25 units of energy for each unit of energy invested. The other technologies (active solar, electrically powered heat pump, and a synthetic gas fueled hot air furnace) had energy ratios of 1.7–5.6. The low energy ratios for active solar energy systems (both air and water) and conventional space heating methods are due to the fact that these technologies employ energy-intensive materials in the equipment used to produce and distribute residential heat. Passive solar energy systems use few components beyond the relatively low energy intensity materials used for standard construction techniques and generally use no energy to distribute the captured heat. Based on these estimates and projected life cycle costs for these energy producing techniques, as well as on some standard energy-conserving techniques, it is apparent that the United States would produce more energy per dollar and energy input with conservation and passive solar strategies than with residential heating techniques depending on coal as a primary fuel.