新能源制氢及氢能应用浅述

氢能作为一种清洁、可储存的能源,是世界新能源和可再生能源领域正在积极开发的二次能源。氢能具有巨大的发展潜力,因此氢能在全球范围内获得了极大的关注和发展。简述了氢能环境分级和常规的氢能制取方法,介绍了新能源制取“绿色氢气”的基本原理和系统组成。以容量为5 000 Nm³·h^-1和20 000 Nm³·h^-1的制氢系统为例,分析了制氢系统的占地面积、投资构成和影响新能源制氢成本的因素,结果表明电价和制氢系统年运行小时数是影响新能源制氢成本的两个关键因素。最后讨论了氢能作为原料和动力燃料的应用途径。     

火电机组供热能力提升技术比选与经济性分析

热电联产集中供热是发电行业节能减排的重要措施。针对目前供热能力提升需求现象,研究了热泵、双背压、光轴和热电解耦改造的技术特点和应用情况;同时以某发电厂300MW机组为基础,进行了工程改造和经济性分析,得出:光轴技术改造相对最优,改造后每年可增加供热量107.5万GJ,实现年经济收益673万元。     

热电联产中供热煤耗计算方法的探讨

<正> 一、急需制定合理的热价体系热电联产是一种既有明显经济效益,又有广泛社会效益的优越能量生产方式。近年来,热电联产供热亏损的普遍性挫伤了热电厂供热的积极性,妨碍着热化事业的进一步发展。1985年在国家豁免供热税收的情况下,全同供热亏损2.38亿元,亏损面积达93％,仅北京热电总厂就亏损7347万元。造成供热亏损的主要原因在于热价制定的不合理,使供热价格低于供热成本,没能真正体现供热热能的价值。此外,由于近年来燃料价格的不断上涨,而供热热价却没能进行相应的、合理的调整。致使供热亏损现象日趋严重。不合理的热价体系已严重影响着热化事业的发展。因此,制定一个合理的热价体系是一项十分重要而又紧迫的任     

金属纤维悬浮液中天然气水合物生成特性实验研究

水合物缓慢的生成速率已经成为水合物储运天然气技术应用的一大障碍。基于静态强化水合物生成技术,以含悬浮金属纤维的表面活性剂溶液作为水合储气介质,研究4.0～7.0 MPa下天然气水合物在悬浮溶液中的生成动力学特性。研究结果表明,金属纤维优良的导热性能够促进水合物快速生成,同时纤维的粗糙表面可促进水合物成核,水合物在金属纤维悬浮体系中的储气量与储气速率均明显高于表面活性剂溶液中的水合特性。在实验压力下,悬浮体系中水合物成核诱导时间明显降低,同时储气量可以达到87.3～129.6 m³·m^-3,比表面活性剂溶液中的增加了5.0%～23.4%;储气速率达到4.4～25.1 m³·（m³·min）^-1,比表面活性剂溶液中的提高了1.1%～39.8%。研究结果可为水合物储气技术在天然气储运方面的应用提供技术参考。     

褶皱式玻璃纤维基底的钒基催化剂性能研究

基于NH₃选择性催化还原（selective catalytic reduction, SCR）反应机理,对采用褶皱式玻璃纤维基底的钒基催化剂在重型柴油机中的应用性能进行模拟研究,并与传统堇青石基底钒基催化剂进行对比。利用国六发动机台架测试结果对模拟程序进行了验证,然后研究了氨氮比、NO₂/NO_x比及空速对褶皱式玻璃纤维基底的钒基催化剂在低温下NO_x转化及NH₃泄漏特性的影响。结果表明：低温下褶皱式玻璃纤维基底钒基催化剂的NO_x转化性能明显优于相同条件下的堇青石基底钒基催化剂。氨氮比的增加对褶皱式玻璃纤维基底的钒基催化剂的NO_x转化性能无明显影响;当氨氮比从0.8增加到1.2时,在200 ℃~500 ℃的区间内NH₃的泄漏量由1×10^-6提高到100×10^-6。NO₂/NO_x比增加可有效提高钒基催化剂的低温性能。当温度为150 ℃时,NO₂/NO_x比由0提高为0.5,钒基催化剂的NO_x的转化效率从14.0%上升到76.0%,而NH₃泄漏量由428×10^-6下降为9×10^-6。当温度为200 ℃时,30 000 h^-1空速下钒基催化剂的NO_x转化效率为98.5%,比90 000 h^-1下提升近30.0%;NH₃泄漏量为7×10^-6,比90 000 h^-1下降低150×10^-6。     

背压式供热机组热力系统优化探讨

火力电厂的凝汽式汽轮机组为了提高循环热效率,全部采用了抽汽回热系统,利用抽汽加热凝结水和给水,回收热量,减少排汽损失.背压机组没有回热抽汽,机组做功能力增加,汽轮机排汽量增大也使对外供热量提高.通过经济性对比分析得出结论,取消背压式汽轮机组回热加热器,仍能保证机组的循环热效率,同时提高了供热机组的经济效益.     

小型热电站要简化设计 降低造价 缩短工期

<正> 小型热电站套用大电厂设计模式必须改革国家大力提倡发展集中供热与热电联产,支持各地及各企业建设了一批小型热电站,对于节约能源、增加电力、改善环境及提高经济效益都有显著的作用,普遍受到欢迎。但这类小型热电站也面临一些问题。目前已建的小热电大多是套用大电厂的设计模式,“照虎画猫”,采用大电厂的一些标准,因此造价较高,工期也长,影响了小热电的进一步发展。例如,一座两台35吨/时锅炉、两台3000千瓦背压机组的小热电站,总造价要2100—2500万元,平均每千瓦3500—4000元,工期一般为二年。建设内     

节能低碳技术案例

1热电厂循环水余热利用技术咨询单位:北京源深节能技术有限责任公司项目使用情况及节能效果:项目使用情况及节能效果:采用10台吸收式热泵将凝汽器部分排入大气热量回收,在不增加电厂容量和排放,以及耗煤量和发电量都不变的情况下,回收余热能力可达82兆瓦,提高了电厂供热量和热效率,减少了冷却水塔蒸发充水量。投产运行后,增加供热能力82兆瓦,每年节能3.2万吨标煤,减少二氧化碳排放8万吨、二氧化硫280吨、二氧化氮240吨、灰渣8200     

凝汽式汽轮机热电联产技术改造及节能效果分析

南海长海电厂50MW的凝汽式汽轮机热力性能低,为避免机组关停,提高机组热效率,通过热电联产技术将其改造为非调整抽汽式供热机组,发电的同时对纺织工业园进行集中供热。该改造方案通过增加非调整抽汽口,从汽轮机第8级向外抽汽,同时对抽汽管路系统、控制水系统、旋启式止回阀、压力控制器等相应部件进行了调整。改造后机组经济效益、社会效益明显,达到了热电联产的要求,具有显著的节能效果。     

主动式冷梁性能对房间气流组织影响模拟研究

以某主动式冷梁送风房间为模型，利用计算流体力学（CFD）软件模拟了主动式冷梁性能对房间气流组织的影响，并将模拟值和实测值进行了对比，验证了模型的准确性。利用该模型研究了主动式冷梁出风速度、出风温度、出风角度、出风高度以及回风口位置对房间气流组织的影响。结果表明：若仅改变出风速度，当出风速度从1 m·s⁻¹增大到4 m·s⁻¹时，预期平均通感P_M下降，不适人员比例P_D先降后升，出风速度为2 m·s⁻¹时，P_D最小，为9%，此时人员对环境的满意度最高；若仅改变出风角度，当出风角度为45°时房间气流组织分布最佳；若仅改变出风高度，当出风高度为2.33 m时房间气流组织分布最佳。在出风温度为20 °C、出风速度为4 m·s⁻¹时，比较不同回风口位置（上部、中部、底部）时距离地面高度Y=1.2 m截面的气流组织变化，发现回风口位于底部时该截面温度最高，空气速度最小，空气龄最大，P_D最小，为28%，此时人体冷热感觉较舒适。     

垃圾焚烧热电联产蒸汽参数选择

针对垃圾焚烧热电联产时,采用中温中压及中温次高压蒸汽参数对全厂投资及经济性的影响进行研究。以日处理规模为600 t·d^-1的生活垃圾焚烧设施作为研究对象,从主机设备参数、主机设备投资额、经济指标、营业收入及投资回收期等5个方面进行分析。研究结果表明,采用中温次高压参数时,垃圾焚烧设施热电联产全厂热效率较采用中温中压参数时提高1.7%,热电联产时全年总收入较采用中温中压参数时提高11.5%,且经济性更好,静态投资回收期约为4.73年。     

N600MW纯凝汽机组改造为供热机组的可行性研究

小热电联产机组关闭后形成的供热负荷,将由中、大型凝汽机组改造为供热机组实现。对N600MW亚临界纯凝发电机组提出两种改造方案,并进行了技术经济分析。     

Independent thermal storage power station with molten salt:Technology and evaluation

储能电站可解决可再生能源间歇性和不稳定性的问题,满足常规电力系统和区域能源系统效率,安全性和经济性的迫切需要.本文提出了一种新的蓄热电站技术----独立熔盐蓄热电站,进行了独立熔盐蓄热电站原理的介绍,概念设计和技术经济评价.结果表明:独立熔盐蓄热电站初期投资很低,仅为6152.88元/kW,投资回收期短,在3年以内.独立熔盐蓄热电站占地面积小,可建在城市中实现热电联供,总能效率可由单纯发电的30%提高到80%以上.     

Study of an incrementally loaded multistage flash desalination system for optimum use of sensible waste heat from nuclear power plant

Existing practice of nuclear desalination cogeneration incurs loss of nuclear plant power generation because it competes for live steam with nuclear plant steam turbine. Such loss is completely avoided with the nuclear desalination plant design proposed in the present study. The plant called GTHTR300 is based on a high‐temperature gas reactor rated at 600 MWt. Gas turbine is used to replace steam turbine as power generator. The gas turbine converts about a half of the reactor's thermal power to electricity while rejecting the balance as sensible waste heat to be utilized in a multistage flash (MSF) plant for seawater desalination. A new MSF process scheme is proposed and optimized to efficiently match the sensible waste heat source. The new scheme increments the thermal load of the multistage heat recovery section in a number of steps as opposed to keeping it constant in the traditional MSF process. As the number of steps increases, more waste heat is utilized, and top brine temperature for peak water production is increased. Both tend to increase water yield. Operating with a similar number of stages, the new process is shown to produce 45% more water than the traditional process operating over the same temperature range. As a result, the GTHTR300 yields 56,000 m³/d water and generates 280 MWe power at constant efficiency with and without water cogeneration. Copyright © 2012 John Wiley & Sons, Ltd.     

燃气轮机在热电联产工程中的应用状况分析

燃气轮机是21世纪乃至更长时间内能源高效转换与洁净利用系统的核心动力装备.介绍了燃气轮机的发展现状及其在热电联产工程中的应用,简述了联合循环和简单循环燃气轮机电厂的基本组合方式,并列举了目前应用在热电联产工程中的几种主要的燃气轮机.阐述了燃气轮机相对于常规火电机组的优点,分析了影响燃气轮机在热电联产工程中推广的因素,并对我国燃气轮机的发展前景进行了展望.     

A novel MCFC hybrid power generation process using solar parabolic dish thermal energy

In this paper, a novel molten carbonate fuel cell hybrid power generation process with using solar parabolic dish thermal energy is proposed. The process contains MCFC, Oxy-fuel and Rankine power generation cycles. The Rankine power generation cycles utilized various types of working fluid to emphasize taking advantage of the cycles in different thermodynamic conditions. The required hot and cold energies are provided from solar dish parabolic thermal hot and liquefied natural gas (LNG) cold energies, respectively. The carbon dioxide (CO₂) from MCFC effluent stream is captured from the process at liquid state. The process total heat integrated and in this regards, no need to any hot and cold external sources with the net electrical power generation. The energy and exergy analysis are conducted to determine the approaches to improve the process performance. This integrated structure consumed 2.30 × 10⁶ kg h⁻¹ of air and 2.67 × 10⁶ kg h⁻¹ of LNG to generate 292597 kW of net power. The products of this integrated structure are 6.25 × 10⁴ kg h⁻¹ of condensates, 183 kg h⁻¹ of water vapor, 2.20 × 10⁶ kg h⁻¹ of MCFC effluent stream, 2.60 × 10⁶ kg h⁻¹ of natural gas and 1.10 × 10⁵ kg h⁻¹ of CO₂ in liquid state. The presented new integrated structure has overall thermal efficiency of 73.14% and total exergy efficiency of 63.19%. Also, sensitivity analysis is performed for determination of the process key parameters which affected the process operating performance.     

Using pyrolytic acid leaching as a pretreatment step in a biomass fast pyrolysis plant: Process design and economic evaluation

Removing alkali and alkaline earth metals (AAEMs) from biomass, with pyrolytic acids, before pyrolysis leads to increased organic oil and sugar yields. These pyrolytic acids are produced and concentrated within the pyrolysis process itself. The purpose of this paper was to evaluate under which conditions acid leaching of pinewood, bagasse and straw can improve the technical and economic feasibility of a pyrolysis process. Therefore, a preliminary process design for the implementation of acid leaching at a pyrolysis plant, with a biomass capacity of 5 and 50 t h⁻¹, was made and compared with a pyrolysis plant using the untreated biomass. Target products were heating oil and/or additional pyrolytic sugars.It has been calculated that with the leaching step the heat for pyrolysis and drying of the biomass can still be supplied by the combustion of the char and gases, but insufficient excess heat is available to produce electricity for the process. Critical for the economics of the acid leaching pyrolysis process are the amount of extractives in the biomass (organics ending up in the waste water) but not its moisture content. Mechanical dewatering before thermal drying turns out to be very important. The economics of the presented approach turned out to be very sensitive to the plant scale, CAPEX and obviously to the biomass price. At the current market scenario and state of proven techniques the production of sugars and heating oil from bagasse at 50 t h⁻¹ is the most economic option (IRR 15.4%).     

燃气轮机热电联供系统性能评估案例

对某供热厂的燃气轮机热电联供系统进行了研究,将燃煤分产和燃气分产进行了全方面的比较,其性能评价对合理应用CHP有重要作用。在热电分产的节能性方面,以燃气-蒸汽联合循环电厂和燃气锅炉作为比较的基准线,全年平均节能率为8.9%;在运行经济性方面,燃气轮机系统与燃煤锅炉分产相比,每年节省46万元,与燃气锅炉分产相比,每年节省182万元,且节省费用随着电价的增加而增加,随着气价的增加而减少。另外,与燃煤锅炉分产相比时,还随着煤价的增加而增加;在排放物方面,燃气轮机联供系统与燃煤分产和燃气分产对比,NOx减排量并不显著,而其余排放物有明显地减少。燃气轮机系统与燃煤以及燃气锅炉相比具有一定的优越性,在设计合理的情况下具有良好的前景。     

Performance assessment of a Stirling engine plant for local micro‐cogeneration

In this paper, we evaluate the viability of a 9.5‐kW_e wooden pellet‐fueled Stirling engine‐based micro‐cogeneration plant as a substitute for small‐scale district heating. The district heating systems against which the micro‐cogeneration plant is compared are based either on a pellet‐fueled boiler or a ground‐source heat pump. The micro‐cogeneration and district heating plants are compared in terms of primary energy consumption, CO₂ emissions, and feasibility of the investment. The comparison also considers an optimally operated individual 0.7‐kW_e pellet‐fueled Stirling engine micro‐cogeneration system with exhaust gas heat recovery. The study is conducted in two different climates and contributes to the knowledge base by addressing: (i) hourly changes in the Finnish electricity generation mix; and (ii) uncertainty related to what systems are used as reference and the treatment of displaced grid electricity. Our computational results suggest that when operated at constant power, the 9.5‐kW_e Stirling engine plant results in reduced annual primary energy use compared with any of the alternative systems. The results are not sensitive to climate or the energy efficiency or number of buildings. In comparison with the pellet‐fueled district heating plant, the annual use of primary energy and CO₂ emissions are reduced by a minimum of 25 and 19%, respectively. Owing to a significant displacement of grid electricity, the system's net primary energy consumption appears negative when the total built area served by the plant is less than 1200 m². On the economic side, the maximum investment cost threshold of a CHP‐based district heating system serving 10 houses or more can typically be positive when compared with oil and pellet systems, but negative when compared with a corresponding heat pump system. Copyright © 2010 John Wiley & Sons, Ltd.     

A district heating system based on absorption heat exchange with CHP systems

In order to decrease the energy consumption of large-scale district heating systems with cogeneration, a district heating system is presented in this paper based on absorption heat exchange in the cogeneration system named Co-ah cycle, which means that the cogeneration system is based on absorption heat exchange. In substations of the heating system, the temperature of return water of primary heat network is reduced to about 25°C through the absorption heat-exchange units. In the thermal station of the cogeneration plant, return water is heated orderly by the exhaust steam in the condenser, the absorption heat pumps, and the peak load heater. Compared with traditional heating systems, this system runs with a greater circuit temperature drop so that the delivery capacity of the heat network increases dramatically. Moreover, by recovering the exhausted heat from the condensers, the capacity of the district heating system and the energy efficiency of the combined heat and power system (CHP system) are highly developed. Therefore, high energy and economic efficiency can be obtained.