分析固体生物质燃料检验标准与其行业发展之间的关系

本文阐述了固体生物质燃料的意义及国内外发展现状。在可利用原料资源丰富及国家政策大力支持的基础上下,主要探讨了固体生物质燃料检验标准对固体生物质燃料技术发展的作用。立足于绿色能源和清洁燃料的初衷,对比煤炭标准提出固体生物质燃料需要完善的部分。     

生物质颗粒燃料在沈阳地区发展的制约因素和对策研究

阐述了沈阳市利用生物质能源的基本情况和推进生物质颗粒燃料的优势。分析了生物质颗粒燃料在沈阳市推广应用过程中存在的问题,针对这些问题提出了对策。     

沈阳市生物质颗粒燃料推广应用前景分析

阐述了沈阳推广生物质颗粒燃料的必要性及重要意义。分析了生物质颗粒燃料在沈阳市推广应用过程中存在的问题,并针对这些问题提出了一系列解决方法与对策。对生物质颗粒燃料的商品化和大规模利用进行了展望,指出生物质颗粒燃料在沈阳地区具有良好的发展前景。     

生物质发电的效益分析

介绍了我国生物质资源利用现状及存在的主要问题,以某电厂利用生物质发电为例,从原燃料的用量、污染物排放情况及环境经济效益等方面进行分析,说明利用生物质发电是节能减排的重要途径。     

中国生物质燃烧排放SO2、NOx量的估算

根据各地区生物质燃料消耗状况和SO2、NOx排放因子，估算了20世纪90年代中国生物质能源利用过程中的SO2、NOx排放量，并给出了分省区，分生物质燃料类型的排放清单，研究表明，中国生物质燃料消耗及其排放的SO2，NOx量分别从1991年的38.1万t和54.9万下降为1999年的33.2万t和45.3万t，在地区，燃料类型上分布不平衡；SO2和NOx排放量均较大的包括山东，江苏、河北，内蒙古，湖北等，其中，内蒙古SO2排放量最大而山东省NOx排放量最 ；秸杆是SO2和NOx排放的最主要来源，薪柴次之；牲畜粪便对SO2贡献率接近30%，而对NOx贡献率仅3%-4%。     

生物质成型燃料生产应用技术及经济效益分析

介绍了目前国内外生物质燃料中的颗粒燃料、棒状燃料等生产技术及生物质燃料的应用技术;针对当前全球能源的严峻形势,对运用生物质成型燃料的生产应用技术作了具体的经济分析和应用对比。     

生物质燃料的产品性能、生产工艺与效益的初步分析

提出了利用牛粪、秸秆生产生物质燃料的工艺、设备与效益分析.     

双炉室气化燃烧一体化环保型生物质热水锅炉的研究

本研究根据生物质燃料的燃烧特性,经反复推算,研究开发出适合于生物质燃料的燃烧设备-1.4MW双炉室气化燃烧一体化环保型生物质热水锅炉,并对锅炉进行了热工和环保指标测试,结果表明,该锅炉具有很好地热工和环保性能,此项技术的成功研发对推广利用生物质能,改善我国煤烟型大气污染日益严重的状况具有重大的现实意义。     

生物质和煤混合燃烧污染物排放特性研究

在试样的质量以及其他的试验条件基本相同的情况下，在恒温下对一种典型的生物质以及它们以一定的比例所得的混合燃料进行污染物排放特性分析。结果表明，在试验用煤中加入生物质（质量比为1：1）后，燃料NOx转变率降低了2%-33%。燃料SOx转变率降低了10-17%。     

生物质转化能源技术的发展现状及趋势探讨

能源短缺问题已成为制约经济社会发展的瓶颈,研究开发新的能源代替传统不可再生能源成为急需要解决的焦点问题。生物质能是由植物的光合作用固定于地球上的太阳能,通过生物质能转换技术可以高效地利用生物质能源,生产各种清洁燃料,替代煤炭、石油和天然气等燃料。对近些年生物质能源技术的发展现状进行了简要讨论,指出了生物质能的利用具有广阔的发展前景,在不久的将来,生物质能源必将成为能源结构中重要一部分,实现能源结构良好可持续发展。     

关于有机废物类生物质能历史定位及其能源价值评估指标探讨

中国是煤炭消耗的第一大国,同时又是有机废物生物质贮存量第一大国。本文叙述了全球生物质能的历史定位,生物质能的主要评价指标,生物质的能源转换技术和生物质能可供给量模型分析与预测实例,以及我国有机废物类生物质能源化利用途径,并探讨了有机废物的能源利用与废物污染防治相结合的生物质能源发展道路。     

Modern Biomass Conversion Technologies

This article gives an overview of the state-of-the-art of key biomass conversion technologies currently deployed and technologies that may play a key role in the future, including possible linkage to CO₂ capture and sequestration technology (CCS). In doing so, special attention is paid to production of biofuels for the transport sector, because this is likely to become the key emerging market for large-scale sustainable biomass use. Although the actual role of bio-energy will depend on its competitiveness with fossil fuels and on agricultural policies worldwide, it seems realistic to expect that the current contribution of bio-energy of 40–55 EJ per year will increase considerably. A range from 200 to 300 EJ may be observed looking well into this century, making biomass a more important energy supply option than mineral oil today. A key issue for bio-energy is that its use should be modernized to fit into a sustainable development path. Especially promising are the production of electricity via advanced conversion concepts (i.e. gasification and state-of-the-art combustion and co-firing) and modern biomass derived fuels like methanol, hydrogen and ethanol from ligno-cellulosic biomass, which can reach competitive cost levels within 1–2 decades (partly depending on price developments with petroleum). Sugar cane based ethanol production already provides a competitive biofuel production system in tropical regions and further improvements are possible. Flexible energy systems, in which biomass and fossil fuels can be used in combination, could be the backbone for a low risk, low cost and low carbon emission energy supply system for large scale supply of fuels and power and providing a framework for the evolution of large scale biomass raw material supply systems. The gasification route offers special possibilities to combine this with low cost CO₂ capture (and storage), resulting in concepts that are both flexible with respect to primary fuel input as well as product mix and with the possibility of achieving zero or even negative carbon emissions. Prolonged RD&D efforts and biomass market development, consistent policy support and international collaboration are essential to achieve this.     

Characteristics of nanoparticles emitted from burning of biomass fuels

The characteristics of the particles of the smoke that is emitted from the burning ofbiomass fuels were experimentally investigated using a laboratory-scale tube furnace and different types of biomass fuels： rubber wood, whole wood pellets and rice husks. Emitted amounts of particles, particle-bound polycyclic aromatic hydrocarbons （PAHs） and water-soluble organic carbon （WSOC） are discussed relative to the size of the emitted particles, ranging to as small as nano-size （〈70 nm）, and to the rate of heating rate during combustion, differential thermal analysis （DTA） and thermogravimetric analysis （TG） techniques were used to examine the effect of heating rate and biomass type on combustion behaviors relative to the characteristics of particle emissions. In the present study, more than 30% of the smoke particles from the burning ofbiomass fuel had a mass that fell within a range of 〈 100 nm. Particles smaller than 0.43 μm contributed greatly to the total levels of toxic PAHs and WSOC. The properties of these particles were influenced by the fuel component, the combustion conditions, and the particle size. Although TC--DTA results indicated that the heating rate in a range of 10-20℃did not show a significant effect on the combustion properties, there was a slight increase in the decomposition temperature as heating rate was increased. The nano-size particles had the smallest fraction of particle mass and particle-bound PAHs, but nonetheless these particles registered the largest fraction of particle-bound WSOC.     

Characterization and problems of indoor pollution due to cooking stove smoke

Findings from the five groups of matched houses, each using either cattle dung, wood, coal, kerosene or liquid petroleum gas (LPG) as cooking fuels are presented with emphasis on cross comparison of indoor pollution levels during the cooking period. The houses using LPG were considered as controls. The characterization of pollution was made by measurements of total suspended particulates (TSP), carbon monoxide, nitrogen dioxide, formaldehyde, sulfur dioxide and particle sizing of TSP, which were further analysed for the evaluation of levels of polycyclic aromatic hydrocarbons (PAHs). A correlation between the pollutants as a function of fuel type has also been looked for. The study revealed that 50–80% of the TSP emissions from biomass and coal-burning cooking stoves were in a respirable fraction of ≤2 μm size and that a large amount of the PAHs (> 75%) belonged to this fraction only. Air quality biomass-using houses was the worst among the users of the five aforementioned fuels and levels were relatively high. The findings stress that a conserted effort towards a solution should be made as a large fraction of the world's population regularly uses biomass as a prime domestic fuel. The problems associated with cooking stoves in India and immediate research needs are outlined.     

秸秆主流能源化技术研究与经济性分析

秸秆生物质作为1种可替代化石燃料的清洁能源,对环境保护和能源结构转型意义重大。我国农作物产量丰富,在秸秆的综合利用方面有较大潜力。就整个秸秆能源化产业而言,我国正处于有序推进阶段,但国内核心技术和设备水平与国际先进水平之间存在差距,产业效益仍不理想,企业对财政补贴有较强的依赖性。在充分认识我国秸秆利用现状的基础上,针对秸秆乙醇技术、秸秆沼气技术、秸秆热解技术和秸秆固化成型技术,探讨了国内外秸秆能源化技术和应用进展,追踪了解除发酵抑制、优化厌氧消化性能、开发热解炭降解潜力以及激活成型燃料黏结性能等技术热点问题。基于经济性分析提出了全组分利用、气肥联产模式、大宗产物梯级利用等针对能源化技术的效益提升手段,并对比了政策补贴和技术提升对企业效益的影响。最后从政策角度和新技术角度对秸秆产业发展方向提出了建议。     

Herbaceous layer production and utilization by herbivores under different ecological conditions in an arid savanna of Kenya

A three-year study was done to determine herbaceous biomass production and its utilization by herbivores in an arid zone inhabited by a largely nomadic population in northern Kenya. The indicator selected for study was aboveground live standing biomass of grasses, forbs, dwarf shrubs and the total sum biomass of these vegetation categories (total herbaceous layer). Sampling was done along grazing gradients in order to estimate the utilization levels in the arid zone 7 and the semi-arid zone 6. Mean peak standing biomass for grasses, forbs, dwarf shrubs and total herbaceous layer under non-grazed conditions was 184.4, 374.2, 1094.4 and 1504.0 kg/ha in eco-zone 7, respectively. In the zone 6, mean peak standing biomass was 55.3, 98.8, 4259.1 and 4320.1 kg/ha under non-grazed conditions, respectively. Results indicated graminoid removal to be respectively 57.1–99.8% and 24.2–87.2% of mean peak standing aboveground live biomass in the zone 7 and 6. Forb utilization in zone 7 was estimated to be 51.5–99.3%. Mean peak forb standing biomass however, showed a general increase on grazed sites compared to the non-grazed plot in zone 6. The corresponding utilization of the dwarf shrub layer was estimated to be in the range 40.5–80.0% and 76.6–92.3% in zone 7 and 6 respectively. Total herbaceous layer consumption of 39.3–85.3% and 74.0–90% was estimated for zone 7 and 6 respectively. These findings suggest that herbivores exert considerable control over biomass dynamics of the herbaceous layer in this zone and contribute to degradation in heavily utilised areas. Efforts to understand and tackle the desertification problem in this area must therefore take this fact into account.     

Biomass-based negative emission technology options with combined heat and power generation

Biomass-based combined heat and power (CHP) generation with different carbon capture approaches is investigated in this study. Only direct carbon dioxide (CO₂) emissions are considered. The selected processes are (i) a circulating fluidized bed boiler for wood chips connected to an extraction/condensation steam cycle CHP plant without carbon capture; (ii) plant (i), but with post-combustion CO₂ capture; (iii) chemical looping combustion (CLC) of solid biomass connected to the steam cycle CHP plant; (iv) rotary kiln slow pyrolysis of biomass for biochar soil storage and direct combustion of volatiles supplying the steam cycle CHP plant with the CO₂ from volatiles combustion escaping to the atmosphere; (v) case (iv) with additional post-combustion CO₂ capture; and (vi) case (iv) with CLC of volatiles. Reasonable assumptions based on literature data are taken for the performance effects of the CO₂ capture systems and the six process options are compared. CO₂ compression to pipeline pressure is considered. The results show that both bioenergy with carbon capture and storage (BECCS) and biochar qualify as negative emission technologies (NETs) and that there is an energy-based performance advantage of BECCS over biochar because of the unreleased fuel energy in the biochar case. Additional aspects of biomass fuels (ash content and ash melting behavior) and sustainable soil management (nutrient cycles) for biomass production should be quantitatively considered in more detailed future assessments, as there may be certain biomass fuels, and environmental and economic settings where biochar application to soils is indicated rather than the full conversion of the biomass to energy and CO₂.

     

Global warming potential factors and warming payback time as climate indicators of forest biomass use

A method is presented for estimating the global warming impact of forest biomass life cycles with respect to their functionally equivalent alternatives based on fossil fuels and non-renewable material sources. In the method, absolute global warming potentials (AGWP) of both the temporary carbon (C) debt of forest biomass stock and the C credit of the biomass use cycle displacing the fossil and non-renewable alternative are estimated as a function of the time frame of climate change mitigation. Dimensionless global warming potential (GWP) factors, GWP_bio and GWP_biouse, are derived. As numerical examples, 1) bioenergy from boreal forest harvest residues to displace fossil fuels and 2) the use of wood for material substitution are considered. The GWP-based indicator leads to longer payback times, i.e. the time frame needed for the biomass option to be superior to its fossil-based alternative, than when just the cumulative balance of biogenic and fossil C stocks is considered. The warming payback time increases substantially with the residue diameter and low displacement factor (DF) of fossil C emissions. For the 35-cm stumps, the payback time appears to be more than 100 years in the climate conditions of Southern Finland when DF is lower than 0.5 in instant use and lower than 0.6 in continuous stump use. Wood use for construction appears to be more beneficial because, in addition to displaced emissions due to by-product bioenergy and material substitution, a significant part of round wood is sequestered into wood products for a long period, and even a zero payback time would be attainable with reasonable DFs.