废弃生物质灰分含量与热值的差异性和相关性及其测定方法

为探究生物质能源化利用中灰分含量和热值的函数变化规律及测定方法,检索2001—2021年已发表的相关文献,获得380个不同类型的生物质样本的灰分含量和高位热值数据,并对测定方法进行分析。结果表明：1）不同热值测定标准对热值的测定结果的评价影响可以忽略不计,而根据固体矿物燃料标准测定的灰分含量结果会显著低于按照生物质燃料标准的测定结果;2）草本植物类生物质的灰分含量为7.96%～9.19%,高于木本植物的2.26%～3.37%,但其平均热值（17.45MJ/kg）却低于木本植物（19.61MJ/kg）;3）草本植物的高位热值与灰分含量呈负相关,相关系数（r）的绝对值为0.567～0.918,高于木本植物的0.136。高位热值与化学元素（碳、氢、氮、硫、氧）含量的决定系数（R2）为0.936 7～0.973 7,高于与灰分、挥发分和固定碳含量的决定系数0.812 0～0.971 4,前者函数的拟合效果更好;4）应用近红外光谱技术建立的生物质水分、灰分含量和热值模型的预测偏差较小,小于参考方法的重复性界限,因此该测定方法更便捷,在生物质产业中具有很大的应用潜力。     

受控条件下氧分压对生物质废弃物堆肥臭气排放的影响

为获得适用于受控生态生命保障系统的低能耗和低排放的堆肥氧气供应参数,采用氧气和氮气混合气体模拟受控条件下的气体供应,以厨余垃圾和园林废弃物为堆肥原料,通过设置氧分压为5%（T1）、15%（T2）和30%（T3）的3个处理,探究氧分压对堆肥理化性质及NH₃和H₂S排放的影响。结果表明：T2处理有助于物料快速降解和堆体升温,堆体最高温度（65.95 ℃）和高温期持续时间（14 d）高于其他2个处理;T2处理NH₃累积排放量分别比T1和T3处理减少了65.35%、24.01%。相关性分析表明,O₂浓度、EC、C/N、NH₄⁺-N是影响恶臭气体排放的主要因素。综合堆肥理化指标和恶臭气体排放情况,氧分压为15%可以同时缩短堆肥周期和减排臭气,研究结果可为受控生态生命保障系统中有机循环系统的构建提供参考。     

Chemicals from biomass: petrochemical substitution options

As a source of chemicals, biomass has several intrnsic advantages over fossil mass: it is renewable, flexible through crop switching, and adaptable through genetic manipulation. Inflexibility of the fossil mass resource is compensated for by highly effective technology for production of olefins and aromatics, economies of scale, and a highly developed system of conversion products with large markets. Direct and indirect strategies to substitute for petrochemicals are based on ecological succession concepts. A proliferation of lignocellulosic fractionation processes is arising from the need for inexpensive, homogeneous, chemically useful biomass feedstocks.     

High-grade fuels from biomass farming: potentials and constraints

The key parameters controlling the productivity and the cost of net high-grade fuel from a system for biomass agriculture and conversion are analyzed. Performance depends sensitively on a "symbiotic" interaction between agronomy and technology. The conditions for obtaining net productivity and costs are explored for U.S. grain alcohol as a reference point. Currently practiced technology consumes more high-grade fuel than it generates. Some potentials and constraints for future systems, including use of other plant species and conversion systems, are explored.     

Fuel ethanol from cellulosic biomass

Ethanol produced from cellulosic biomass is examined as a large-scale transportation fuel. Desirable features include ethanol's fuel properties as well as benefits with respect to urban air quality, global climate change, balance of trade, and energy security. Energy balance, feedstock supply, and environmental impact considerations are not seen as significant barriers to the widespread use of fuel ethanol derived from cellulosic biomass. Conversion economics is the key obstacle to be overcome. In light of past progress and future prospects for research-driven improvements, a cost-competitive process appears possible in a decade.     

Fuels from biomass: integration with food and materials systems

The development of fuels from biomass can lead naturally to dispersed facilities that incorporate food or materials production (or both) with fuel production, forming adaptive systems that can be modified to meet evolving needs and constraints. The technology that is appropriate to each system needs to be worked out, taking into account associated food and materials opportunities in order to decrease the ultimate cost of energy delivered to the consumer. I analyze possible systems based on sugarcane, corn, and guayule.     

废纸制浆固废物刨花板制备工艺研究

【目的】探索废纸制浆固废物的资源化新途径。【方法】以废纸回收中分离的固废物为黏合剂,杨木刨花为增强体,采用热进冷出工艺压制刨花板。通过正交试验,研究刨花添加量(质量分数)、板材密度及热压工艺参数(热压时间、热压温度)对板材的静曲强度(MOR)、弹性模量(MOE)和内结合强度(IB)的影响。【结果】密度、热压时间和热压温度对板材的MOR、MOE和IB均有显著影响;刨花添加量对MOR和IB影响显著,对MOE影响不显著。综合考虑各因素对板材力学性能的影响和生产实际,优化得到的热压工艺参数为:刨花质量分数60%,板材密度0.95g/cm3,热压温度185℃,热压时间90s/mm。【结论】在优化热压工艺条件下制备的板材,其最佳力学性能可以达到GB/T 4897.4-2003在干燥状态下使用的结构用刨花板的质量要求。     

生物质飞灰对餐厨垃圾两相厌氧消化的影响

为解决餐厨垃圾在厌氧消化过程中的酸抑制问题,并为生物质飞灰提供新的资源化利用途径,在产酸相中添加不同比例的飞灰,研究了生物质飞灰对餐厨垃圾中温两相厌氧消化过程中产酸和产气的影响。结果表明:添加生物质飞灰可以提高酸化相的p H值,促进餐厨垃圾酸化,添加3%的生物质飞灰,产酸相的挥发性脂肪酸(VFA)的平均浓度为9 845.45 mg·L-1,比空白处理(CK)提高了49.66%,差异显著;添加3%生物质飞灰处理的产甲烷相更稳定,产气效果更好,累积产气量为27.43 L,比0、1%、4%和5%的飞灰添加比例分别高了25.15%、13.70%、4.34%和6.55%;添加3%生物质飞灰处理的平均负荷产气量为490.33 m L·g VS-1,比0、1%、4%和5%的飞灰添加比例平均值分别提高了22.49%、12.35%、6.36%和8.22%。研究表明,添加生物质飞灰有助于促进餐厨垃圾酸化和提高产甲烷相的产气量;在高有机负荷的时候,添加生物质飞灰有助于提高系统运行的稳定性。     

Emission of methyl bromide from biomass burning

Bromine is, per atom, far more efficient than chlorine in destroying stratospheric ozone, and methyl bromide is the single largest source of stratospheric bromine. The two main previously known sources of this compound are emissions from the ocean and from the compound's use as an agricultural pesticide. Laboratory biomass combustion experiments showed that methyl bromide was emitted in the smoke from various fuels tested. Methyl bromide was also found in smoke plumes from wildfires in savannas, chaparral, and boreal forest. Global emissions of methyl bromide from biomass burning are estimated to be in the range of 10 to 50 gigagrams per year, which is comparable to the amount produced by ocean emission and pesticide use and represents a major contribution ( approximately 30 percent) to the stratospheric bromine budget.     

竹浆废水酸析固废农用处理初步研究

竹浆废水酸析处理后产生以木质素为主要成分的固体废物。通过室内试验与盆栽试验,研究了竹浆废水酸析处理过程中产生的酸析固废与磷矿粉混合进行农业利用处理,并对处理效果进行分析。结果表明,将磷矿粉与酸析固废混合可有效地中和酸析固废中的游离酸,反应时间需要4 d以上。酸析固废能部分活化磷矿粉中的磷,提高磷的有效性。酸析固废与磷矿粉以质量比为1：1混合4 d后活化效果最佳。对酸析固废活化磷矿粉中磷的机理研究表明,酸析固废中的残留酸是磷活化的主要因子。小白菜(Brassica campestris ssp．chinensis L．)和萝卜(Raphanus sativus L．)盆栽试验结果表明,经酸析固废活化后的磷矿粉有一定肥效,肥效介于磷矿粉与钙镁磷肥之间。     

栽培模式对四倍体刺槐生物量和叶片营养的影响

通过比较3种栽培模式对四倍体刺槐无性系K5的生物量及叶片营养含量的影响,以及每年刈割1次模式下3个四倍体刺槐无性系与普通刺槐的生物量差异和每年刈割2次模式下3个四倍体刺槐无性系之间的生物量差异,获得了生物量和营养含量最佳结合点的刺槐饲料林适宜栽培模式,达到了充分开发其饲料价值的目的。结果表明:每年刈割2次模式的第2次叶片的粗蛋白含量显著高于其他2种栽培模式(P0.05),且单株叶质量与其他2种栽培模式无显著差异;每年刈割1次模式下四倍体刺槐无性系K2的单株总质量和叶质量均显著高于无性系K4和K5及普通刺槐(P0.05);每年刈割2次栽培模式下无性系K2的单株总质量和叶质量显著高于无性系K4(P0.05)。综合考虑叶片生物量和营养,四倍体刺槐无性系K2表现最好,且定植当年不刈割,第2年开始每年刈割2次(春天不平茬,6月初和8月底刈割)的栽培模式最佳。     

红霉素药渣作家禽蛋白质饲料的营养价值评价

用蛋白质自动定氮仪和Beckman-121MB型氨基酸分析仪测定红霉素药渣,粗蛋白质为18.38 %,10种必需氨基酸总含量为3.839 %,其中赖氨酸0.265 %、蛋+胱氨酸0.704 %、色氨酸0.347 %、苏氨酸0.213 %、亮氨酸0.690 %、缬氨酸0.343 %、异亮氨酸0.375 %、苯丙+酪氨酸0.400 %、组氨酸0.282 %、精氨酸0.220 %。真可利用蛋氨酸(0.53 %)与大豆饼(0.54 %)接近。以家禽理想蛋白质为模型计算必需氨基酸平衡指数(IEAA)是0.662～1.323,结合失衡度等指数的计算结果,证实红霉素药渣为家禽饲料的良好蛋白源。