户用炉具使用生物质炭化燃料的排放特征及其减排效果评估

文章对比研究了核桃壳和竹子两种生物质原料及其炭化燃料、颗粒燃料在户用炉具中使用时的排放特征和炊事热效率;探究了炭化燃料排放颗粒物的粒径分布;运用SEM观察了竹炭燃料燃烧排放PM_(2.5)和PM_(0.4)的微观形貌。测试结果表明:同颗粒燃料相比,两种炭化燃料基于单位有效能量的排放因子(PM_(2.5)和NO_(X))分别降低了75.5%~78.7%和56.3%~67.5%;相比原始生物质燃料,两种炭化燃料基于单位有效能量的排放因子(PM_(2.5)和NO_(X))分别降低了94.2%~95.1%和62.5%~71.6%;相比颗粒和原始生物质燃料,核桃壳炭化燃料的CO排放因子降低了29.3%~43.1%,但竹炭燃料的排放因子未降低。此外,炭化燃料炊事热效率高于颗粒和原始生物质燃料炊事热效率。颗粒物粒径分布显示,炭化燃料燃烧所排放的颗粒物以细颗粒物为主,其粒径分布峰值在0.4μm以下,占PM_(10)总质量的50%左右,而粒径小于2.5μm的颗粒物则占PM_(10)总质量的80%以上。

基于非介入侦听电力调度数据网非法接入检测平台研究及应用

基于非介入侦听电力调度数据网非法接入检测平台实时侦听并分析在线传输的调度业务数据,通过采集变电站网络记录分析装置数据,实现对调度业务应用数据变化过程的高效监测,同时形成海量的调度运行数据信息库;系统平台基于IEC104规约,将调度数据信息点进行自动关联,并实现在线校核,有效减轻了调控人员业务数据点核对、控制实验等工作压力,提升了自动化系统运行的稳定性和电网调控运行技术支撑能力。

提高市政道路施工沥青路面平整度的方法和措施

中国城市化进程的持续推进使得城市基础设施建设发生了根本性改变,市政道路是城市建设的基础构成,市政道路的质量直接关系到城市的发展,满足了城市建设、社会生产和居民等多种需求,因此市政道路不仅仅是建设工程,更是民生工程,全面提升市政道路施工质量才能够实现城市建设水平的进一步提升,有效满足国家发展和社会建设的需求。沥青路面是市政道路施工的重要构成部分,其平整度直接关系到工程质量和道路安全,随着城市车流量的增加,市政道路也面临着更加严峻的考验。此次研究围绕市政道路施工沥青路面平整度的主要影响因素展开分析,在此基础上探究提高市政道路施工沥青路面平整度的方法和措施。

未/难培养微生物可培养策略研究:机遇与挑战

微生物分布广泛、种类众多、功能多样,虽体积微小但功能强大,关乎人类的安全健康和生态的稳定发展,在整个地球生命系统中起着举足轻重的作用。17世纪以来,研究者们一直努力获得、了解和利用这些微生物,然而目前分离方法的局限性使得环境中绝大部分微生物仍不能被纯培养,严重阻碍了我们对微生物生命活动规律的认知。因此,如何分离获得这些仍未被培养出来的“暗物质”是微生物研究面临的严峻挑战和重大机遇。本文分析了环境中制约微生物分离培养的因素,综述未/难培养微生物可培养研究的最新进展,着重论述优化的传统培养方法及网络导向培养、膜扩散培养、微流控分选培养和细胞分选培养等新型技术的应用,并对未来研究进行展望,探索多技术联合使用策略,为未/难微生物资源的挖掘及开发利用提供借鉴。

基于文献计量学的玉米秸秆利用及关键共性技术分析

为促进玉米秸秆全价值利用,该研究以中国知网(CNKI,China national knowledge infrastructure)数据库和Web of Science(WOS)核心数据库作为数据来源,利用知识图谱可视化软件,绘制玉米秸秆利用领域的知识图谱,以便全面了解玉米秸秆利用领域的研究现状和发展趋势,总结其面临的主要问题,并在此基础上深入挖掘分析玉米秸秆利用关键共性技术。玉米秸秆利用研究大致可分为1990—2007年及2008—2022年两个阶段。在后一阶段,各研究团队逐渐构成以肥料化、饲料化为主,燃料化为辅的玉米秸秆利用研究体系。经文献梳理发现,玉米秸秆利用研究大致经历了3次阶段性热点迁移,每次变化时长约为10a;中国玉米秸秆利用研究已取得较多成果,主要集中在秸秆还田和生物质能源生产方面;通过对知识图谱综合分析发现,玉米秸秆利用的热点方向包括生物质能源生产、土地改良和保护、畜牧业发展和饲料生产。最后,知识工程和归纳法分析结果表明,玉米秸秆利用技术仍存在收运不及时、还田质量低、秸秆制饲料技术不成熟、能源化技术成本高和附加值低等瓶颈。故在农业废弃物资源化利用这一国家重大需求驱动下,该文主要关注并分析了未来研究应重点聚焦的13项玉米秸秆全价值利用关键共性技术。该研究可为促进中国玉米秸秆全价值利用提供参考。

Analytical study on pyrolyzed products of Desmodesmus sp.cultivated in BG11

Pyrolysis-Gas Chromatography-Mass Spectrometry(Py-GC/MS)was adopted to determine the changes in component of BG11-cultivated Desmodesmus sp.(BG11/8-10)pyrolyzed products at different temperatures(300℃-800℃).The results of analysis on a series of total ions chromatogram(TIC)showed that pyrolyzed products of BG11/8-10 at different temperature mainly included aliphatic hydrocarbons,nitrogen compounds,aromatic hydrocarbons,fatty acids,ketones,alcohols,aldehydes and furan compounds.Compared to the bio-oil(42.36%)generated by pyrolysis at 700℃,the relative content of bio-oil generated at 800℃was the highest up to 56.96%.However,higher temperature could easily cause the generation of large quantities of such pollutants as nitrogen compounds and polycyclic aromatic hydrocarbons(PAHs).Therefore,based on lower pollutant discharge and higher bio-oil yield,the optimal pyrolysis temperature of BG11/8-10 was around 700℃.

Thermal cracking products and bio-oil production from microalgae Desmodesmus sp.

Qualitative and quantitative analyses of thermal cracking products from Desmodesmus sp.were performed based on pyrolysis-gas chromatography-mass spectrometry(Py-GC/MS)at different temperature regimes(350℃-750℃).After further analysis of a series of total ions chromatogram(TIC)and summarized,thermal cracking products of Desmodesmus sp.at different temperature regimes can be obtained,which mainly comprised of aliphatic hydrocarbons,nitrogen compounds,aromatic hydrocarbons,fatty acids,ketones,alcohols,aldehydes and furan compounds.Compared to bio-oil production at 650℃(32.07%),Desmodesmus sp.pyrolyzed at 750℃could produce the highest bio-oil content of 42.25%.However,higher temperature could lead to the formation of contaminants(nitrogen compounds and PAHs)more easily.Therefore,considering the higher content of bio-oil conversion and less pollutants generation,the optimum temperature for Desmodesmus sp.thermal cracking conversion was about 650℃.

Life cycle assessment of pyrolysis process of Desmodesmus sp.

This paper described a comprehensive assessment of the pyrolysis process of 1 kg Desmodesmus sp.cultivated in BG11 medium at the optimum temperature by using life cycle assessment method.This assessment took 1 kg of Desmodesmus sp.as a functional unit,and chose energy efficiency analysis and potential environmental impact as assessment indices.The results showed that the energy conversion efficiency index of the pyrolysis process was above 1,which meant the pyrolysis process was beneficial.The primary impact of the pyrolysis process on the environment was eutrophication;which followed by photochemical ozone synthesis and acidification;and global warming impact was the last.The overall environmental impact during the whole life cycle was 1347.63 mPET2000.

Isolation of microalgae with growth restriction and nutrient removal from alkaline wastewater

In order to isolate a well-tolerated microalgae strain and study its capability of wastewater treatment,a newly microalgae strain was isolated and identified from fresh water.The phylogenetic analysis indicates that this strain has a close relationship with Desmodesmus sp.,named as EJ 9-2.The effects of temperature,pH value and NaCl concentration on growth of Desmondesmus sp.were investigated;the capability of nutrient removal from alkaline wastewater was also observed.Desmodesmus sp.EJ 9-2 had a wide pH adaptation range(3-12)and could remove nitrogen,phosphorus and COD which might substantially decrease the cost of biofuel production.The research can provide evidence for outdoor large-scale cultivation of microalgae.

Effects of biomass pellet composition on the thermal and emissions performances of a TLUD cooking stove

Indoor air pollution is ranked the 5th in the Global Burden of Disease index of the World Health Organization(WHO).Almost half of the world’s population depends on biomass fuels to meet their basic energy requirements for cooking,lighting and space heating.When fuel is badly combusted in poorly designed stoves,the fuel-stove combination results in high level of noxious emissions entering the home,accumulating to dangerous levels.In this study,a Chinese unvented top lit updraft(TLUD)biomass stove was operated with three different biomass pellets formed from corn stover,cotton stalk and peanut shells.The performance tests were conducted according to the latest standard from the Chinese Ministry of Agriculture.The calorific value,moisture level,volatile matter and elemental composition are reported for each.The thermal efficiencies of the stove were 15.3%,10.1%and 14.4%,respectively.The cooking powers were 2.68 kW,1.61 kW and 1.57 kW.The exhaust was collected using a hood and tunnel.The CO,NO and NOX were drawn after passing 1.5 m along the tunnel and the Particulate Matter(PM)was sampled after 1.6 m.The Emission Factors(EF)for CO,NO,NOX and PM_(10) are reported on both a mass per unit energy delivered to the pot(g/MJ_(NET))and a mass per mass of fuel basis(g/kg).The range for CO was 4.56-7.61 g/MJ_(NET)(11.25-21.25 g/kg);NO was 0.75-1.23 g/MJ_(NET)(2.09-3.04 g/kg);NO_(x) was 1.13-1.90 g/MJ_(NET)(3.14-4.86 g/kg);PM_(10) was 0.59-0.85 g/MJ_(NET)(1.67-2.09 g/kg).The range in these values was more significantly influenced by the fuel moisture content and the percentage of volatile matter than by variations in the elemental composition.

Inventory analysis of carbon footprint on greenhouse gas emission of large-scale biogas plants

Inventory analysis of greenhouse gas emission for large-scale biogas plants using carbon footprint method still needs to be improved.Based on the life cycle theory,the application of carbon footprint on four large-scale biogas plants was analyzed in this paper,which comprehensively considered project progresses of civil engineering construction,operation and comprehensive utilization of residues and slurry.Also the greenhouse gas emissions during the construction and waste removal stages were analyzed and estimated.The carbon footprint of those plants was analyzed in different types and scales.The results showed that the larger scale plant will produce relatively lower carbon footprint.The greenhouse gas emission of energy production,utilization during the period of anaerobic digestion accounted for more than 96%of the entire life cycle emission.The proportion of greenhouse gas emissions on equipment,demolition recycling and transportation phases was smaller,which was less than 1.5%and should be simplified in calculation.The greenhouse gas emission of building materials production can be ignored.