Sickle bush (Dichrostachys cinerea L.) field performance and physical–chemical property assessment for energy purposes

The sickle bush (Dichrostachys cinerea (L.) Wight & Arn.) comprises a woody legume shrub which is widely distributed throughout of the tropical areas of Africa, Asia and Oceania, being found as well in Cuba where it represents a difficult to control invasive plant. It holds great silvopasture and energy crop potentials. In southwestern Spain a two year field trial was conducted contemplating also another six hardwood taxa commonly used as energy crops. The sickle bush above ground dry biomass fraction was 60.4%; sickle bush displayed a high transpiration rate during hot days (3.02 kg m⁻² d⁻¹ to 6.82 kg m⁻² d⁻¹); cold winter temperatures (<−2 °C) together with hot and dry summer air (<20% relative humidity) committed survival and growth. The physical-chemical wood properties and the pellets thereof derived were analyzed and compared to those of the other energy crop taxa. The within other woody species normal chemical composition range coupled to a high wood density and energetic use properties (19.2 MJ kg⁻¹ higher heating value, 29 g kg⁻¹ ash content) all allow for an industrial use. Pellets evidenced also good physical and mechanical properties (690 kg m⁻³ bulk density, 42 g kg⁻¹ moisture content). However, the mechanical durability (93.9%) was slightly less than that required by the non-industrial use standards, therefore further improvements should be studied. All of the above could encourage scrubland cuts in Cuba as a mechanical control method, in addition to the expansion of plantations within of their tropical climate based natural habitats.     

干法除尘技术在转炉提钒上的应用

转炉提钒应用干法除尘技术是在提钒转炉的除尘系统设计中采用国内先进的干法除尘工艺,采用汽化冷却烟道、LT干法转炉烟气净化技术。针对转炉提钒烟气CO含量较低、没有回收价值的情况采用燃烧法充分利用热量,蒸汽回收量增加明显。吹炼过程采用炉气中CO含量控制技术,解决了因炉气中O2含量难于控制造成爆炸的难题,形成了一套成熟可靠的防爆操作工艺方法。烟气通过净化后使烟气含尘量达到16.1 mg/m3。此外,提钒转炉干法除尘灰全部用于提钒自循环,提高了钒的回收率。投产以来,除尘效果良好,未发生大、中型爆炸,真正实现了低能耗、低排放、低故障运行,对于迅速发展的铁水预处理转炉、AOD炉等小烟气量、低CO含量的除尘具有示范推广作用。     

转炉蒸发冷却器结垢前后数值模拟

针对转炉干法除尘系统蒸发冷却器内部结垢现象影响静电除尘器除尘效率的问题,采用FLUENT软件对蒸发冷却器内部结垢前后的速度场、压力场及温度场进行了数值模拟。研究结果表明:烟气进入蒸发冷却器后流速降低,压力逐渐增加;由于雾化水的蒸发冷却作用,烟气温度由800℃降低190℃;蒸发冷却器结垢后烟气压力场与温度场均有所改变,出口平均压力由-104 Pa降低到-229 Pa,平均温度由190℃提高到224℃;出口处烟气温度较结垢前提高了34℃,烟气温度升高导致静电除尘器入口处粉尘比电阻超出最佳电除尘器参数的范围,导致电除尘效率降低。     

干气提浓乙烯技术在茂名石化炼油厂的工业应用

茂名石化炼油厂催化和焦化装置副产的干气含有高附加值的乙烯,如果将其回收将会产生较大的经济效益。四川天一科技股份公司与中石化燕山分公司联合开发了回收催化干气中乙烯组分的干气提浓乙烯技术,并于2004年在燕山分公司获得工业应用,取得较大效益。干气提浓乙烯技术在茂名石化炼油厂的工业应用中,变压吸附单元采用两段变压吸附+吸附剂抽真空再生技术,能提高乙烯回收率;产品精制单元采用MDEA胺液洗涤+氧化锌精脱硫技术脱除杂质H2S;采用NaOH溶液碱洗方法脱除杂质CO2;采用四川天一科技公司脱氧催化剂和脱氧技术脱除杂质O2。应用情况表明,该技术能将炼油厂干气中的C2和C2+组分有效回收,并脱除H2S、CO2、O2等杂质,为乙烯裂解装置提供合格的原料气;同时,也暴露出一些问题,如:原料气带液,吸附剂粉碎,压缩机运行周期短,富乙烯气脱氧精度不易控制等,需要在今后的研究、设计和生产中继续改进和完善。     

世界油页岩开发利用的近况——并记2012年国外两次油页岩国际会议

2012年国际油价在90～100美元/bbl之间波动,在这种情况下,页岩油的生产在经济上仍有利可图.2012年国外召开了两次大型油页岩国际科技会议.世界油页岩资源蕴藏量折算成页岩油高达4.8× 101bbl,其中美国占到了77％.估计中国页岩油资源约有0.35×1012bbl,但探明储量不够,应加强勘查,落实更多可采储量.中国正在引进和自主开发大处理量的油页岩干馏生产页岩油的新工艺.当前世界页岩油年产量约156×105,其中中国约70× 104t,爱沙尼亚约66× 104t,巴西约20× 104t.世界油页岩电站发电能力以爱沙尼亚最大,容量达2300MW以上,其他国家规模很小.爱沙尼亚今后将主要采用油页岩干馏新技术增产页岩油.美国至今仍无油页岩干馏炼油的工业化生产,但有多家公司、科研机构和大学在进行油页岩地下和地上干馏炼油的现场开发和基础研究.德国、法国、加拿大、澳大利亚等发达国家的一些公司关注页岩油生产,并参与或开发油页岩干馏新工艺.约旦、土耳其、印度等发展中国家以及以色列加强了油页岩资源的勘查或国际合作,开展了油页岩加工利用的可行性研究.     

CO2 reforming of methane over Ni/ZnAl2O4 catalysts: Influence of Ce addition on activity and stability

The catalytic performance of Ni supported on Ce-promoted ZnAl₂O₄ was evaluated in methane dry reforming. The effect of different nominal loadings of cerium (3, 5 and 7 wt%) in the activity, product yield and stability was studied. Ce presented a promote effect in catalytic activity, product yield and especially in stability. However the catalytic performance was considerably influenced by the amount of cerium. SEM images presented smaller particles and TPR profiles revealed stronger active phase/support interaction by Ce addition which led to increasing methane conversion and decreasing coke deposition. Although high amount of Ce was not in favor of its promoting effect due to aggregation of CeO₂ on the catalyst surface. Among the catalysts investigated, the optimal catalytic activity and stability was achieved over the sample with 5 wt% of cerium.     

Enhancement of Escherichia coli bacterial biomass and hydrogen production by some heavy metal ions and their mixtures during glycerol vs glucose fermentation at a relatively wide range of pH

Escherichia coli growth and H₂ production were followed in the presence of heavy metal ions and their mixtures during glycerol or glucose fermentation at pH 5.5–7.5. Ni²⁺ (50 μM) with Fe²⁺ (50 μM) but not sole metals stimulated bacterial biomass during glycerol fermentation at pH 6.5. Ni²⁺+Fe³⁺ (50 μM), Ni² +Fe³⁺+Mo⁶⁺ (20 μM) and Fe³⁺+Mo⁶⁺ (20 μM) but not sole metals enhanced up to 3-fold H₂ yield but Cu⁺ or Cu²⁺ (100 μM) inhibited it. At pH 7.5 stimulating effect on biomass was observed by Ni²⁺+Fe²⁺+Mo⁶⁺. H₂ production was enhanced 2.7 fold particularly by Ni²⁺+Fe³⁺+Mo⁶⁺ at the late stationary growth phase. Whereas at pH 5.5 increased biomass was when Fe²⁺+Mo⁶⁺ or Mo⁶⁺ were added. H₂ yield was decreased compared with that at pH 6.5, but metal ions again enhanced it. During glucose fermentation at pH 6.5 biomass was increased by the mixtures of metal ions, and 1.2 fold increased H₂ yield was observed. At pH 7.5 Ni²⁺+Fe²⁺ increased biomass but Cu⁺ or Cu²⁺ had suppressing effect; Fe³⁺+Mo⁶⁺ stimulated H₂ production. At pH 5.5 biomass also was raised by Ni²⁺+Fe²⁺+Mo⁶⁺; H₂ yield was increased upon Mo⁶⁺ and Mo⁶⁺+Fe²⁺ or Mo⁶⁺+Fe³⁺ additions. The results point out the importance of Ni²⁺, Fe²⁺, Fe³⁺ and Mo⁶⁺ and some of their combinations for E. coli bacterial growth and H₂ production mostly during glycerol but not glucose fermentation and at acidic conditions (pH 5.5 and 6.5). They can be used for optimizing fermentation processes on glycerol, controlling bacterial biomass and developing H₂ production biotechnology.     

现代柴油机燃烧过程中微粒质量的变化规律

利用全气缸取样技术,对不同工况下的柴油机燃烧过程中微粒组分质量生成历程进行了研究.实验结果表明,燃烧形成的干碳烟质量曲线呈单峰状,峰值出现在上止点后10~15°CA之间,在燃烧后期,约有81%~92%的干碳烟被氧化.随着燃空当量比从=0.41增大到=0.53,缸内干碳烟质量峰值增加了4.57%~45.42%;喷油压力升高,虽然干碳烟质量峰值增大,但氧化比例也明显提高.此外,在燃烧初期,微粒中可溶有机物SOF的含量超过80%.     

炼厂干气湿法脱硫流程模拟分析

对炼厂干气进行脱硫处理非常必要,可减轻设备和管道腐蚀,减少催化剂中毒,同时还可以回收利用其中的硫来制造硫磺和硫酸。本文以一套加氢装置为例,介绍了采用ASPEN PLUS软件进行的干气湿法脱硫[以甲基二乙醇胺（MDEA）溶液为吸收剂】模拟分析结果。由于吸收反应在电解质溶液中进行,吸收塔模拟计算选用ASPEN PLUS流程模拟软件的电解质NRTL模型,解析塔物性方法选用UNIFAC物性。原料气指标：流量为617．74kg／h,温度为40℃,H声含量为1．2％（摩尔分数）。分析结果表明：吸收剂温度以不高过38℃为宜,再生温度以不超过114℃为宜;取吸收塔理论板数为12块,吸收剂的质量流量为2300—2500kg／h,吸收剂中MDEA浓度为25％．再生塔顶温度为100℃．则脱硫处理后干气中的H签含量可满足国家燃烧排放标准的要求（〈20μL／L）。     

Biomass for residential and commercial heating in a remote Canadian aboriginal community

Most residents of Canada's 300 remote communities do not have access to natural gas and must rely upon higher cost and/or less convenient heat sources such as electric heat, heating (furnace) oil, propane, and/or cord wood. This research sought to determine the techno-economic feasibility of increasing biomass utilization for space and hot water heating in remote, off-grid communities in Canada and abroad using a two-option case study approach: 1) a district energy system (DES) connected to a centralized heat generation energy centre fuelled by wood chips; and 2) a decentralized heating option with wood pellet boilers in each individual residence and commercial building. The Nuxalk First Nation Bella Coola community was selected as a case study, with GIS, ground surveys, and climate data used to design DES routes and determine heat demand. It was determined that biomass has the potential to reduce heat costs, reduce the cost of electricity subsidization for electrical utilities, reduce greenhouse gas emissions, and increase energy independence of remote communities. Although results of the analysis are site-specific, the research methodology and general findings on heat-source economic competitiveness could be utilized to support increased bioheat production in remote, off-grid communities for improved socio-economic and environmental outcomes.