秸秆直燃发电的生命周期评价

应用生命周期评价(LCA)方法,以秸秆直燃发电项目为研究对象,对秸秆的种植、运输、粉碎干燥和燃烧发电等4个过程进行了清单分析,并分别计算出4个过程的能耗及其对环境的影响.结果表明,每燃烧100kg秸秆发电,对环境的总影响负荷水稻秸为247.36毫人当量,小麦秸为268.74毫人当量,玉米秸为267.33毫人当量.秸秆直燃发电对环境影响主要为烟尘和灰尘,对局部地区的影响占据首位.以水稻秸秆为例,100kg水稻秸秆在直燃发电过程中整个系统共从环境吸收CO2167.60kg,向环境释放CO2164.24kg,由此看到,秸秆直燃发电项目在减少温室气体排放上能起积极作用.     

层燃燃煤工业锅炉直接喷燃木糠的危害及对策

层燃燃煤工业锅炉改烧生物质燃料时,应针对燃料的燃烧特性对锅炉进行相应改造,若不加改造而是直接更换燃料及其供给系统,则会危及锅炉的安全运行。主要分析了直接向层燃燃煤工业锅炉中喷燃木糠替代燃煤对锅炉安全运行的危害,并有针对性地提出了相应的对策及建议。这对今后如何科学合理地利用生物质燃料替代燃煤,使锅炉安全、经济、节能、环保地运行提供了参考。     

生物质与炉渣混燃循环流化床锅炉设计构想

目前生物质工业锅炉多采用层燃方式,生物质燃料灰熔点较低,灰成分碱金属含量高,结渣、受热面积灰、腐蚀等情况比较严重,制约层燃生物质锅炉的发展。另外在工业锅炉占很大份额的燃煤层燃炉炉渣含碳量普遍高于20%,造成能源浪费。本文根据生物质燃料以及层燃炉渣的特点,提出燃用生物质与层燃炉渣混合燃料循环流化床锅炉的设计构想。通过合理的燃料配比提高生物质燃料灰熔点,稳定流化床循环物料,采取一定措施减少碱金属的升华和尾部受热面积灰、腐蚀。并对其在小型工业锅炉应用的"节能减排"效果进行了预测。     

生物质颗粒燃料及直燃式生物质锅炉

根据生物质颗粒燃料的燃烧特性设计制造直燃式生物质工业锅炉,对直燃式生物质工业锅炉的常见燃烧方式、生物质层燃锅炉的一些独特结构进行分析探讨,有助于燃生物质颗粒锅炉性能的完善和提高。     

生物质锅炉改燃轻油锅炉能效案例分析

通过对某生物质锅炉改燃轻油锅炉能效案例分析,分析改造后锅炉的能效状况及节能水平,为燃生物质工业锅炉改造成燃轻油工业锅炉在技术方案上提供数据支持和理论分析,进而帮助改造完善改造方案。     

秸秆直燃发电系统的生命周期评价

以装机容量25 MW的生物质秸秆直燃发电系统为评价对象,进行生命周期评价.结果表明,秸秆直燃发电1万kWh,可吸收CO2 2502.87 kg,向环境排放SO237.39 kg,NOx90.37 kg,与燃煤发电相比,虽然氮氧化物的排放量有所增加,但减少了温室气体及硫氧化物的排放,污染物的排放主要发生在秸秆燃烧阶段.每发电1万kWh消耗能量15 340.2 MJ,秸秆预处理阶段是能量消耗的主要阶段,须要输入能量13 830.5MJ.秸秆直燃发电过程对环境影响的总负荷为35.18人当量.在此过程中,烟尘居环境影响总负荷的首位.     

小型燃生物质流化床锅炉的研究与设计

通过一台10 t/h燃生物质工业锅炉的开发设计,研究分析了选择鼓泡流化床(BFB)燃烧方式的优势和燃用生物质颗粒燃料产生的问题。详细介绍了锅炉的本体结构、燃烧系统、烟气与汽水循环以及几处关键点的技术改进措施。     

杭州市工业锅炉运行现状及能效状况分析

首先对杭州市工业锅炉运行现状进行分析,结果表明:1 t/h以下锅炉占总量49%,为工业锅炉主体;燃煤/生物质锅炉占在用锅炉总数61%,耗能占总耗能74%,为耗能主体。然后对183台工业锅炉进行能效测试,并定量分析了排烟温度tpy、过量空气系数α、炉渣含碳量C_(lz)、负荷率及热效率ηj、整体能效状况指标,结论如下:tpy和α普遍偏高;燃煤/生物质锅炉C_(lz)控制较好;锅炉负荷率整体偏低,燃煤/生物质锅炉平均只有58%;ηj燃油(气)锅炉较好,平均为88%,而燃煤/生物质锅炉平均仅为69%。     

燃酒糟锅炉运行性能热态试验研究

针对酒糟的燃料特点,在研究其燃烧机理的基础上,开发了一种燃酒糟锅炉,并对燃酒糟锅炉炉内空气动力场布置对锅炉燃烧及效率的影响、燃酒糟锅炉的实际运行性能进行了热态试验研究,为燃酒糟锅炉以及其它燃生物质锅炉的优化设计和运行提供了可靠依据。     

生物质循环流化床锅炉尾部受热面积灰分析及处理

针对某生物质电厂直燃锅炉尾部受热面严重灰渣沉积情况,结合该电厂生物质原料特性和生物质锅炉运行工况,对生物质直燃锅炉受热面灰渣形成机理及灰渣沉积的影响因素进行分析,明确了在生物质燃料特性和锅炉燃烧方式不变的情况下,受热面灰渣沉积的必然性。结合生物质直燃锅炉实际运行情况,提出通过优化受热面布置和改进烟道结构等措施来解决尾部受热面灰渣沉积积堵问题,并在某生物质直燃锅炉发电厂的优化改进中取得良好效果。     

Techno-economic analysis of wood biomass boilers for the greenhouse industry

The objective of this study is to perform a techno-economic analysis on a typical wood pellet and wood residue boiler for generation of heat to an average-sized greenhouse in British Columbia. The variables analyzed included greenhouse size and structure, boiler efficiency, fuel types, and source of carbon dioxide (CO₂) for crop fertilization. The net present value (NPV) show that installing a wood pellet or a wood residue boiler to provide 40% of the annual heat demand is more economical than using a natural gas boiler to provide all the heat at a discount rate of 10%. For an assumed lifespan of 25 years, a wood pellet boiler system could generate NPV of C$259,311 without electrostatic precipitator (ESP) and C$74,695 with ESP, respectively. While, installing a wood residue boiler with or without an ESP could provide NPV of C$919,922 or C$1,104,538, respectively. Using a wood biomass boiler could also eliminate over 3000 tonne CO₂ equivalents of greenhouse gases annually. Wood biomass combustion generates more particulate matters than natural gas combustion. However, an advanced emission control system could significantly reduce particulate matters emission from wood biomass combustion which would bring the particulate emission to a relatively similar level as for natural gas.     

生物质颗粒燃料燃烧模拟实验

在生物质颗粒燃料燃烧试验用锅炉平台上,进行了多种配风、一、二次风配比、不同的二次送风位置及改变燃料层厚度四个工况下的实验研究。实验结果表明：生物质颗粒燃料锅炉热效率高达77.69%,而锅炉排烟中NOX、SO2等环保指标远远低于燃煤锅炉。燃烧模拟实验为生物质颗粒锅炉设计和运行提供规律性参考数据。     

生物质气化技术锅炉供热的工业化应用特性

以某工业化应用示范项目为对象,研究并讨论了生物质气化技术工业锅炉供热的系统运行特性及能耗情况,分析了示范项目的环境影响及经济性。结果表明：相比其他生物质原料,红木应用于示范项目表现出最佳运行特性;基于红木的系统能耗分析得出排烟损失、循环冷却水热损及炉体散热约占总能量的16%,为项目可节能的方向;示范项目低污染物排放和CO2零排放的环境友好性,低投资回收期和高投资收益的经济性,表明项目运行具有很好的前景。同时,指出了蒸汽销售价格是保证类似规模项目经济效益的关键。     

Integrated study through LCA,ELCC analysis and air quality modelling related to the adoption of high efficiency small scale pellet boilers

This study focuses on the environmental impact assessment of three different high efficiency residential pellet boilers manufactured by an Austrian company. A Life Cycle Analysis (LCA) and an Environmental Life Cycle Costing (ELCC) analysis were performed, along with air quality modelling simulations for two EU case studies to evaluate CO, PM10, SO₂, NO₂ concentration reductions due to the substitution of the innovative boilers in place of obsolete and non environmentally compliant biomass boilers.The SimaPro software (v. 8.05.13, Recipe Midpoint Method) was used for the LCA and ELCC analysis while CALPUFF (v. 6.42) was used for air quality simulations.Boilers emission and efficiency factors operating in real life conditions were used as input data for all environmental impact assessment analysis. Results showed an interesting reduction of both the environmental impact and pellet consumption cost (linked to the highest monetary value in the ELCC analysis) associated to the most innovative boiler model among the three envisaged. Furthermore, it emerged that air quality could be improved in the short term (2020) with the substitution of obsolete and end of life biomass boilers with high efficiency pellet boilers in EU areas where biomass is the main source of residential heating. A potential reduction of local CO, SO₂ and PM10 concentrations from 9% to 23% depending on the pollutant and on the specific case study considered is found for the short term scenario (2020) with respect to the baseline scenario (2010). No significant differences in air quality were evidenced for NO₂ concentrations.     

Economic sensitivity of wood biomass utilization for greenhouse heating application

This paper presents an analysis of the impacts of technical and market changes on the economic feasibility of using wood biomass to produce heat for an average-sized greenhouse in British Columbia. A previous techno-economic analysis determined that the installation of a wood pellet or a wood residue boiler to generate 40% of the greenhouse heat demand is more economical than using a natural gas boiler alone to generate all the heat [1]. As the techno-economic analysis contained forecasted parameters, a thorough sensitivity analysis is needed for sound decision making. This paper extends the previous techno-economic study by assessing the effect of fuel price, wood biomass energy contribution, and greenhouse size changes on the net present value (NPV) when using a wood pellet or wood residue boiler with or without an electrostatic precipitator (ESP). The results indicate that the attractiveness of using wood biomass will increase if the price of fossil fuels increases more than 3% per year or carbon taxes and regulations are applied. Increasing the biomass energy contribution by 20% (to provide 60% of the total heat demand) would still be economical. The installation of a wood pellet boiler or a wood residue boiler is economical for average (7.5 ha) or large (15 ha) greenhouses.     

基于正交设计的分级分区头部流动特性研究

针对某650 MW超超临界燃煤锅炉在深度调峰过程中燃用大同烟煤时无法稳定燃烧的情况开展研究,就如何提高锅炉在低负荷运行中稳燃性的问题,对原煤种进行掺混改良,改变不同富氧燃烧配风方式,利用计算流体力学模拟软件模拟了不同工况的炉内燃烧情况。模拟结果表明：由于锅炉降低负荷运行增加了原煤种的着火难度,固定碳含量低且挥发分高的煤种可以较好适应锅炉运行调整;富氧燃烧可以提高锅炉低负荷运行时的出口烟温,能满足后续脱硝处理的要求;随着富氧燃烧程度的增大,煤粉燃烧耗氧量增加,每秒燃烧的煤粉颗粒数增加,加剧了炉内的燃烧,使燃烧更稳定;当富氧浓度大于27%时,不能高效提高炉内温度,NOx排放量增多;当富氧浓度为27%时,炉膛出口NOx排放量按6%O2折算为负增长的最小值,是该锅炉低负荷投运较为理想的工况。     

Experimental studies on cofiring of coal and biomass blends in India

Concerns regarding the potential global environmental impacts of fossil fuels used in power generation and other energy supplies are increasing worldwide. One of the methods of mitigating these environmental impacts is increasing the fraction of renewable and sustainable energy in the national energy usage. A number of techniques and methods have been proposed for reducing gaseous emissions of NO_x,SO₂ and CO₂ from fossil fuel combustion and for reducing costs associated with these mitigation techniques. Some of the control methods are expensive and therefore increase production costs. Among the less expensive alternatives, cofiring has gained popularity with the electric utility producers. This paper discusses the ‘gaseous emission characteristics namely NO_x,SO₂, suspended particulate matter and other characteristics like specific fuel consumption, total fuel required, actual and equivalent evaporation, total cost of fuel, etc. from a 18.68 MW power plant with a travelling grate boiler, when biomass was cofired with bituminous coal in three proportions of 20%, 40% and 60% by mass. Bagasse, wood chips (Julia flora), sugarcane trash and coconut shell are the biomass fuels cofired with coal in this study.     

生物质就地及时压缩成型技术——Highzones技术

生物质能源在可再生能源中占有举足轻重的地位。大量、高效地利用生物质能源,尤其是我国的秸秆类农业生产废弃物,一直是生物质能利用技术研究开发的重点方向。一种全新的生物质颗粒燃料成型技术(Highzones技术)已由北京惠众实科技有限公司开发成功,在生物质燃料成型技术领域获得了突破性进展。2004年,经过瑞典农业大学生物质技术与化学研究所严格的系统测试,证明Highzones技术的性能优于国际上现有的颗粒成型技术。Highzones的发明可使生物质颗粒燃料的成型设备具有紧凑、经济、安全的特点,便于在生物质原料产地推广使用。通过进一步开发,颗粒燃料成型机还可以与联合收割机配套,实现同时收获粮食与秸秆颗粒燃料。Highzones技术能够消除生物质燃料规模化应用中存在的收、运、储成本高这一"瓶颈"问题,从而使生物质颗粒燃料进入商业化燃料市场,最大可能地替代化石能源。Highzones技术的应用和推广,可使形成一条生物质颗粒燃料生产与消费的产业链,对缓解我国能源紧张、减少二氧化碳排放、促进Z生态绿化产业发展,以及扩大农村就业、增加农民收入和改善其生活条件,将发挥重要作用。     

浅议水煤浆锅炉的技术特点及其应用

本文从节约能源、减少污染物排放的角度出发,阐述说明水煤浆锅炉在节能环保方面的优越性。文章详细介绍了水煤浆燃料的特点;结合工程实例着重说明水煤浆锅炉燃烧系统、除尘、除硫、烟气排放的工艺流程;水煤浆锅炉在燃料消耗、污染物排放2方面与燃煤锅炉的技术经济比较分析,以及水煤浆锅炉的环保效益。     

Evaluation of wood pellet application for residential heating in British Columbia based on a streamlined life cycle analysis

The consequences of using wood pellets to replace traditional firewood for residential heating in British Columbia, Canada have been investigated based on a streamlined life cycle analysis. Survey data in 2002 and 2005 indicated that 1.44 Mt of firewood is used in BC residential heating annually. If current wood-burning residential heating equipments were replaced by their pellet-equivalent counterparts, then only 667 kt of wood pellets would be needed annually and the impacts on human health, ecosystem quality, climate change, and primary energy consumption will be reduced fractionally by 95%, 26%, 17% and 34%, respectively. Savings of $749,277,000 per year in externality can also be achieved, representing a fractional reduction of 94% from the current practice. For every tonne of pellet burnt to replace firewood, $1124 in externality is avoided. In terms of capital investment for new equipment, replacing conventional fireplace, masonry heater and outdoor boiler are desirable whether bulk or bagged pellets are to be used. If bulk pellets are to be utilized then all users except the owners of any type of fireplace inserts should consider switching to wood pellets. For the equipment and pellet type combinations with negative net present value (NPV), the estimated external cost savings and the NPV calculated may be the basis for the establishment of an incentive program. Promoting pellet consumption for residential heating through introducing government subsidies and improving distribution logistics will be beneficial to both pellet producers and local consumers, as well as to the local environment.