塞罕坝机械林场地表可燃物类型划分与载量研究

对塞罕坝机械林场8个林分类型108个林班的地表森林可燃物组成、载量、含水率等进行了调查。结果表明落叶松成林和幼林、樟子松成林和幼林、针叶混交林、桦次生林等林分地表可燃物以枯落物为主,栎次生林和灌木林地表可燃物由枯落物与灌木组成,未成林地与草地可燃物以草本植物为主;地表可燃物载量依次为落叶松成林〉落叶松幼林〉针叶混交林〉樟子松成林〉樟子松未成林〉针阔混交林〉桦次生林〉樟子松幼林〉落叶松未成林〉灌木林〉栎次生林〉草地;草地与栎次生林的含水率最低,着火点也最低,火险危险程度最高;将现有林分按燃烧类型划分为5个类型20个亚类,全场地表可燃物总载量约为2．5×10^6t。     

一种快速测定云南松和华山松林下细小可燃物负荷量的方法

在野外测定云南松和华山松纯林细小可燃物层平均厚度和负荷量的基础上,建立了细小可燃物层的平均厚度与负荷量的关系模型。经验证,云南松和华山松林下细小可燃物负荷量模型的平均误差分别为8.11%和10.43%。根据细小可燃物层的平均厚度推算可燃物负荷量的方法具有数据容易采集、操作简便的优点,适用于凋落物层被人为破坏的林分和灭火指挥员急需数据的紧急情况下进行可燃物负荷量的推算。     

Utilization of semi-natural grassland through integrated generation of solid fuel and biogas from biomass. I. Effects of hydrothermal conditioning and mechanical dehydration on mass flows of organic and mineral plant compounds, and nutrient balances

The use of semi-natural grasslands for the production of renewable energy through conventional conversion techniques faces major limitations because of chemical and physical properties of the biomass. A new conversion procedure was developed which separates the biomass, as silage, into a liquid phase for biogas production and into a solid fraction to be used as fuel. Separation (mechanical dehydration) is carried out with a screw press after mashing with water (hydrothermal conditioning). The effect of hydrothermal conditioning at different temperatures (5, 60 and 80°C) and mechanical dehydration on mass flows of plant compounds into the press fluid was investigated for five grassland pastures typical of mountain areas of Germany. Results show that 0·18 of the crude fibre was transferred into the fluid, whereas more digestible organic compounds, such as crude protein and nitrogen-free extract, showed mass flows of 0·40 and 0·31 respectively. While 0·52–0·89 of potassium (K), magnesium (Mg) and chloride (Cl), which are detrimental for the combustion of the press cake, were transferred into the press fluid, more than 0·50 of calcium, which has positive combustion properties, remained in the press cake. Significantly ( P  <   0·05) higher mass flows were detected at conditioning temperatures of 60°C (K and Mg) and 80°C (crude fibre and nitrogen-free extract) compared with the 5°C treatment. Because of the separation of solids and liquids, high proportions of P (0·61–0·74) and K (0·64–0·85) but only 0·32–0·45 of nitrogen exported from the grassland would be recycled with an application of the digestates from the anaerobic digestion of the press liquid.     

小型制粒机喂料器参数优化与试验

采用离散元法EDEM对喂料器的工作过程进行了数值模拟,定量研究了喂料过程中喂料量的变化规律以及由于物料受螺旋叶片终止断面的影响,产生不稳定、不均匀的"脉动"喂料现象,此现象在转速较低的情况下尤其明显。以主轴直径X1、螺距X2和喂料转速X3为因素,以喂料质量流率Y1、稳定性Y2和出料口落料速度Y3为评价指标,按照3因素5水平正交旋转组合设计试验方法,利用Design-Expert 8.0.6软件回归分析法和响应面分析法,建立了3个因素下喂料评价指标的数学模型。通过与研制的喂料器的实际运送情况进行对比,验证了模型的可靠性。结果表明,3个因素相对喂料质量流率和流率稳定性都具有显著相关性,显著水平分别为P0.01和P0.05,而这3个因素与出料口落料速度无明显相关性;采用响应面法对最佳参数组寻优,得到喂料器的最佳参数组合:轴径为35 mm、螺距为57 mm、转速为139(°)/s,喂料器喂料量波动性减小、喂料稳定性得到提高。采用该参数组的虚拟试验结果显示,喂料器质量流率为13.89 g/s,稳定性为8.46 g/s。实体样机验证试验表明:采用该参数组设计的喂料器可以使得小型环模制粒机的喂料质量流率提高4.28%,喂料变异系数降低16.11%。     

废植物油脂与废聚乙烯塑料共裂解制备燃油研究

研究在高压反应釜中,利用Zr O2/Al2O3/Ti O2多晶泡沫陶瓷催化剂,催化废植物油脂与废聚乙烯塑料共裂解制备燃油。考察了温度、时间、催化剂添加比例、物料质量比等因素对废植物油脂与废聚乙烯塑料共裂解制备燃油的影响。得到适宜的制备条件为反应温度430℃、反应时间40 min、催化剂质量分数15%、物料质量比1∶1,在此条件下,液体产物产率为65.9%。GC-MS分析表明,裂解液体中饱和烃类产物峰面积比例接近100%,其中97.85%为直链烷烃,并初步推断了废植物油脂与废聚乙烯塑料共裂解机理。产物的部分燃料油性能测定结果表明,裂解燃油热值明显高于生物柴油与0号柴油,密度和运动黏度符合0号柴油的标准,冷凝点和冷滤点均优于生物柴油,低温流动性好。     

柴油喷雾燃烧火焰内部碳烟采集与分析

为研究碳烟颗粒在柴油喷雾火焰内部的演变规律,在可视化定容弹喷雾燃烧系统中增加一种基于热泳原理的碳烟颗粒采集装置,获得了喷雾燃烧火焰内部的碳烟颗粒样本,并在高倍透射电镜下获得样本中不同尺度的碳烟形态图像。根据图像中碳烟宏观和微观形态结构特征分析了碳烟生成、聚合等演变历程。通过自行开发的图像处理程序,分析得到碳烟颗粒尺寸参数随喷射距离的变化特征。研究表明,该方法实现柴油机缸内高温高压特征环境下碳烟颗粒的采集与高倍电镜分析技术的有机结合,有效获取柴油喷雾火焰内部碳烟颗粒微观信息,为减少柴油机碳烟排放提供了重要研究手段和基础研究信息。     

喷孔几何特征对孔内流动及近孔区域燃油雾化的影响

采用混合多相流模型与空穴模型相结合的方法,对喷孔内部流动特性及近孔区域燃油喷射及雾化进行数值模拟。计算结果表明,喷孔几何特征对其内部流动特性及近孔区域燃油喷射及雾化具有重要影响,对于截面渐扩的喷孔,孔内空化效应、湍流度均增强,喷孔出口流速提高,喷油压力增大时效果更显著,空穴强度增大能够促进近孔区域燃油快速分裂,使燃油液滴雾化更细小,有利于柴油机油气混合以及性能的提高。对于截面渐缩的喷孔,孔内空化效应受到抑制、湍流度和喷孔出口流速均降低,喷孔出口液柱较长、液块较大,近孔区域燃油雾化程度降低。     

对辊柱塞式成型机设计与试验

基于生物质固化成型领域活塞冲压式成型机能耗低、生产率低和模辊式成型机生产率高、能耗高的特点,提出一种新型对辊式成型方式,并设计和制造了样机。该成型机压辊圆周上均布了一系列柱塞,运行过程中压辊柱塞与环模模孔相互啮合,避免了成型孔之外的物料受到压辊的挤压与摩擦。为测试该成型机的性能,进行了正交试验研究,结果表明,该成型机的较优成型参数为:含水率15%,成型模具长径比5.25,主轴转速47.25 r/min。以木屑为原料,在较优成型参数的条件下进行了成型机性能指标的测试,结果表明,该成型机生产的成型颗粒直径为10 mm,成型颗粒密度为1.15 g/cm3,机械耐久性为96.28%,生产率为75 kg/h,能耗为56 k W·h/t,成型率为95%,工作噪声为79 d B,各项指标均达到设计要求,实现了连续稳定生产。     

Cost analysis of a satellite terminal for forest fuel supply in Finland

As forest fuel demand increases, new logistical solutions are needed. Most of the increase in use is expected to take place in large heat and power production units which set special requirements for the supply as both procurement volumes and transport distances increase. Biomass fuel terminals broaden the spectrum of available supply options by offering cost-effective large-scale biomass storage and processing options for securing the fuel supply in all conditions. This study aimed to study different costs of a satellite terminal and to produce important concept and cost information for developing forest fuel logistics based on future terminals. The figures indicate that terminals do not create direct cost benefits per se: direct supply chains are more economical compared to supply through terminals. However, there are several indirect benefits that can be reached via fuel supply through terminals: regional fuel procurement can be widened to a national scale, security of supply increases through easily available storages, large supply volumes can be delivered by an individual operator, prices remain more stable and a more even quality of delivered fuel can be achieved.     

Bioremediation of the soil contaminated with petroleum oil products using sewage sludge

ABSTRACT

The remediation technologies of soils contaminated with petroleum products are developed in two main directions: the first one encompasses searching for new effective bioagents and the other one explores the ways to activate those microorganisms present in the soil that are capable of degrading oil. The objective of this research was to determine if it is possible to increase the effectiveness of biodegradation of petroleum products by using chemical additives. The soil was supplemented with additives: CuSO4, MnSO4, KMnO4, H2O2, 5% and 10% chemical industry plants sludge, 5% and 10% Stock Company ‘Klaipedos vanduo’ (SC‘KV’) municipal wastewater treatment plants sludge. The data suggest that all the additives statistically significantly stimulated the degradation of diesel fuel (F = 12.01; p = .001) and black oil (F = 9.93; p = .001) compared with the control. It was determined that diesel fuel was degraded the fastest in samples with KMnO4, where efficiency of degradation was 90%, and 88% efficency in samples with 10% chemical industry plants sludge. Black oil was degraded the best in samples, where KMnO4 was added: efficiency of degradation was up to 63%. In the samples with 10% of sewage sludge from chemical industry plant degradation efficiency was 62%.