水热处理对生物质成型炭理化性质的影响

棉秆(CS)及木屑(WS)经高压反应釜水热预处理后压制成型,并于固定床热解炉内进行炭化实验,利用电子万能材料试验机、热重分析仪等分析手段分析水热预处理对生物质成型炭的产率、物理性能(机械强度和表观密度)、热值及燃烧性能的影响。研究表明:随着水热温度的升高,生物质成型炭的产率增加且热值稳定,但燃烧性能变差;经水热预处理制得的生物质成型炭灰分产率均小于18%,固定碳产率均大于60%,满足欧标要求;随着水热温度的升高,生物质成型炭的表观密度及抗压强度均先增加后减小;对比所有实验样品,经230℃水热预处理制得的生物质成型炭(CS/WS-HT230-CB)物理性能及燃烧性能最佳,且均优于商用烧烤炭性能。     

Conversion of coffee residue waste and Eucalyptus globulus leaf extract into an alternative solid fuel

This study presents the conversion of coffee residue and Eucalyptus globulus leaf extract wastes into a solid fuel. The biochar resulting from the carbonization process was developed into a briquette charcoal form. The calorific values of the briquettes were measured by a Parr Isoperibol Bomb Calorimeter and a maximum of 6378.99 cal/g was recorded. They also demonstrated a maximum moisture content of 5.33%, fixed carbon content of 37.67%, ash content of 35%, and volatile matter of 62.50%. The briquettes showed a better quality compared to the commercially available charcoals in the study area, indicating the potential of the briquettes for use as a solid fuel. The results of this work show the prospect of reducing the volume of waste by converting it into energy.     

秸秆成型燃料锅炉的设计及试验研究

根据秸秆成型燃料高挥发性和燃烧稳定的特点,完成了输出热负荷200 kW的秸秆成型燃料锅炉的设计。其炉膛可分为热解区、炭燃烧区与挥发分燃烧区3部分,实现了秸秆成型燃料的分段燃烧。以直径不同的5种玉米秸秆成型燃料进行了试验研究,分别对其输出热负荷、燃气中CO含量及热利用效率进行了测试,发现利用直径为40～50 mm成型燃料时,锅炉的输出热负荷最大,热利用率较高,烟气中CO含量较低。     

生物质型煤的研制与应用

生物质型煤是一种新型型煤,是利用粉煤、生物质等通过一定的生产工艺制作而成,不仅有利于节约能源,同时也可以减少环境污染.文章重点介绍了水分、生物质添加量、粘结剂、原料煤粒度、成型压力、熟化过程、干燥程度对生物质型煤冷强度的影响,添加剂、生物质、配煤量以及煤的种类对生物质型煤热强度的影响.文章还分析了生物质型煤与生物质和煤在燃烧速度和着火性能上的区别,固硫效果与所加固硫剂量之间的关系,并提出了生物质型煤作为气化型煤今后应开展的研究方向与课题.     

成型炭化过程对磷酸-污泥-木屑成型炭性能的影响

以杉木屑和污泥为原料,磷酸为添加剂,探讨成型温度（70~100 ℃）、成型压力（80~110 MPa）和炭化温度（300~600 ℃）对磷酸-污泥-杉木屑成型炭物理性能和产率的影响,并对物理性能最佳的成型炭进行燃烧特性分析和重金属分析。结果表明,成型温度与成型压力对成型炭物理性能的影响相似,随着成型压力的增大和成型温度的升高成型炭物理性能均先升高后下降,炭化温度对成型炭物理性能影响较复杂。经80 ℃和100 MPa成型后再经500 ℃炭化制得的成型炭表观密度与抗压强度最大,分别为1279.0 kg/m³和18.7 MPa,均远高于商用烧烤炭。成型炭产率随炭化温度的升高而减小,由300 ℃的72.0%减至600 ℃的52.2%。较高的成型炭物理性能和产率可在一定程度上降低储存和运输成本,实现生物质废弃物的高效利用。     

Physical properties of rice husk and bran briquettes under low pressure densification for rural applications

Agriculture generates large amount of by-products that could be used to produce energy and reduce the amount of fuelwood required to meet the daily cooking needs, especially in developing countries. Rice is a major crop grown in West Africa and rice husk is a by-product of the milling process. The goal of this study was to develop a low cost system to produce biomass briquettes from rice husks in the context of a rural village. A manual press generating a pressure of 4.2 MPa was developed and used. The influence of the briquette formulation (type of binder, binder content, water addition, and bran content) was studied. The binders investigated were cassava wastewater, rice dust, and okra stem gum. The physical properties (density, moisture content, calorific value, durability, and compressive strength) were tested to identify the briquettes with the highest quality, i.e. greatest physical integrity. The briquettes made with rice dust had the highest durability (91.9%) and compressive strength (2.54 kN), while the briquettes made with cassava starch wastewater had the greatest density (441.18 kg m⁻³). Water added to the rice husk before densification positively influenced the briquette quality while bran seemed to mostly increase the density, but not necessarily the briquette quality. The briquette formulation did not significantly influence the calorific value. With a higher heating value of 16.08 MJ kg⁻¹ dry basis, rice husk briquettes represent an interesting alternative to fuelwood.     

Sustainable charcoal production from biomass

Charcoal products can be produced from biomass sources such as charcoal from wood, woody agricultural products, the biogenic fraction of municipal wastes, nut shells, etc. The liquid and gaseous fractions obtained from biomass are a valuable fuel source; however, the solid fraction (charcoal) has the recovery potential of carbon black or as carbon adsorbent after applying an activation step. Charcoal is produced by slow heating wood (carbonization) in airtight ovens or retorts, in chambers with various gases, or in kilns supplied with limited and controlled amounts of air. Charcoal has the potential to improve soil properties, crop productivity, and carbon sequestration in soil. The most interesting temperature range for the production of the pyrolysis products is between 625 and 775 K. The charcoal yield decreased gradually from 43.5 to 31.0% for the walnut shell and from 38.3 to 25.4% for the spruce wood with an increase of temperature from 550 to 1150 K. The charcoal yield decreases as the temperature increases. The ignition temperature of charcoal increases as the carbonization temperature increases. The charcoal briquettes that are sold on the commercial market are typically made from a binder and a filler.     

Preparation of CaO-rich briquette from powdered semi-cokes by cold-pressing

In this work, CaO-rich briquette coke was prepared by carbonizing the cold pressing briquette composed of powdered char, CaO, and binders. The influences of binder type, binder content in briquette, the CaO/char ratio, and carbonization condition on compressive strength, resistivity, and porosity of the briquette were investigated. Subsequently, the optimum preparation conditions for producing CaO-rich briquetting coke were determined. The obtained results can promote development and optimization of in-situ production of calcium carbide and acetylene from CaO-rich briquetting coke.     

Computation of Instantaneous Fuel Consumption for the Determination of Combustion Efficiency with Special Reference to Coal Briquette Size

This study comprises of the computation of instantaneous fuel consumptions as a straight means for the interpretation of combustion-related characteristics of coal. The model relies on the determination of the extent of combustion by the calculated fuel combustion amounts at specific instants in order to examine the oxidation behavior and possible influences governed by any variable of interest. In this context, coal briquettes prepared by varying dimensions with and without a volume constraint were evaluated and instantaneous fuel consumptions corresponding to the determined instants were computed for comparison rather than introducing the model with a single experiment. Thus, the influences imposed by the enlargement of the briquette volume as well as by the variations in the compactness of briquettes on the effectiveness and efficiency of combustion reactions were dealt. The applicability of the model was checked by the trends revealed from the view of reaction kinetics in terms of activation energies. At the end of the study, the results deduced on the grounds of instantaneous fuel consumption values were seen to have been in full confirmation by those related to reaction kinetics, showing the applicability of the model in reflecting the particular cases during a combustion reaction.     

Properties of charcoal derived from hazelnut shell and the production of briquettes using pyrolytic oil

Hazelnut shells were converted to charcoal and to liquid, and gaseous products using pyrolysis at different temperatures. The chemical compositions and yields of the charcoals were determined as functions of the carbonization temperature. Higher heating values (HHVs) were estimated using both ultimate and proximate analyses. Hazelnut shells and the derived charcoal were densified to briquettes using pyrolytic oil or tar as binder. Briquette properties improved with an increase in briquetting pressures and percentages of binder materials. The best charcoal briquettes were obtained at 800 MPa pressure at 400 K.     

锯末制备生物质成型燃料的试验研究

分别采用冷压成型和炭化成型工艺以锯末制备生物质成型燃料。冷压成型工艺主要考察原料水分、成型压力对燃料的成型性能影响。试验结果表明:原料水分为12%~16%,成型压力为60 MPa的条件下能够制得成型性能较好的生物质成型燃料,其密度与抗跌强度分别能够达到0.94 g/cm3和99%;炭化成型工艺主要考察混合料水分、无烟煤配比、J型粘结剂添加量、成型压力对燃料的成型性能影响。试验结果表明:无烟煤配比为50%、混合料水分为30%、J型粘结剂添加量为8%、成型压力为45 MPa的条件下能够制得成型性能较好的优质生物质成型燃料,其密度与抗跌强度分别为0.93 g/cm3和99.3%。     

Effect of densification variables on density of corn cob briquettes produced using a uniaxial compaction biomass briquetting press

Densification of loose biomass improves its properties for use as fuels. To design efficient briquetting equipment, there is a need to study properties of briquettes under different conditions. In this study, the effects of process variables (pressure, temperature, and hold time) and a material variable (particle size) on the density of corn cob briquettes were investigated. It was discovered that increasing the pressure, temperature, and particle size had positive effects on the density of biomass briquettes. The density of biomass briquettes produced using the selected values of pressure (9, 12, and 15 MPa), temperature (90°C and 120°C), hold time (7.5 and 15 min), and particle size (<2.5 mm and >2.5 mm) ranged between 570 and 1300 kg/m³.     

生物质成型燃料研究现状及进展

本文讨论了发展生物质成型燃料的意义,详细介绍了国内外生物质成型燃料的发展历程及现状,介绍了一些目前采用的新技术和存在的问题.最后对生物质成型燃料的未来进行了展望,指出生物质成型燃料在节能及环保方面将大有作为.     

Comparison of quality and production cost of briquettes made from agricultural and forest origin biomass

This paper presents the quality and cost of small-scale production of briquettes, made from agricultural and forest biomass in north-eastern Poland. The experiment involved production of eight types of briquettes. The highest net calorific value was determined for briquettes made from pine sawdust (18,144 MJ t⁻¹). The value measured for briquettes made from perennial energy plants was over 1500 MJ t⁻¹ lower, and for those made from straw 2000 MJ t⁻¹ lower than for sawdust briquettes. The sawdust briquettes left significantly the lowest amount of ash (0.40% of dry mass). The significantly highest content of hydrogen, sulphur and nitrogen was found in briquettes containing the highest portion of rapeseed oilcake. The quality of briquettes varied and only some of them met the requirements of DIN 51731. Briquettes made from pine sawdust were of the highest quality. The briquette production cost ranged from 66.55 € t⁻¹ to 137.87 € t⁻¹ for rape straw briquettes and for those made from a mixture of rape straw and rapeseed oilcake (50:50), respectively. In general, briquette production was profitable, except for the briquettes made from a straw and rapeseed oilcake mixture.     

新型成型机秸秆碎料形变分析及挤压力控制措施

介绍了一种新型秸秆燃料成型机,阐述了其基本机械结构和工作原理．为了便于分析秸秆燃料压缩成型过程中秸秆碎料形变规律,将成型机工作区域动态地划分为供料区、压紧区、压实区、成型区和保型区等五个工作分区．从秸秆碎料宏观体积、微观组织变化以及秸秆碎料的形变情况,分别探讨了每个分区秸秆碎料的形变特点．成型机压辊对秸秆碎料的挤压力过小会降低成型燃料的品质,挤压力过大则会降低秸秆成型机的寿命．通过研究挤压力与秸秆燃料密度的关系,以控制压缩比为措施设计了新型秸秆成型机的挤压力控制方案．     

Modification of commercial briquetting machine to produce 35 mm diameter briquettes suitable for gasification and combustion

This paper describes an experience on producing 35 mm dia briquettes with a modified commercial briquetting machine and the results of studies on the combustion and gasification behavior of briquettes. Study reveals that at 12% (w.b.) moisture content of groundnut shell powder (1180–150 μm), good quality briquettes can be made, but it reduces the production rate and increases the power requirement. Combustion as well as gasification studies revealed that biomass briquettes of 35 mm diameter do not crumble or disintegrate during the conversion process, therefore these are suitable as feedstock for gasifiers.     

Influence of moisture content and hammer mill screen size on the physical quality of barley,oat, canola and wheat straw briquettes

In order to determine the briquetting characteristics of biomass in a commercial setting, a hydraulic briquetter was used to study the compaction behavior of biomass grinds from barley, oat, canola and wheat straw. The selected straw samples were ground with a hammer mill using screen sizes of 19.05, 25.40 and 31.75 mm and conditioned to three moisture content levels of 0.09, 0.12 and 0.15 (w.b.). The residence time was about 6–10 min before being extruded from the briquetter. The specific energy, throughput, as well as the density, and durability of manufactured briquettes were measured during or after briquetting. The applied compression pressure at different parameter combinations ranged from 7 to 14 MPa. Higher pressure resulted at higher biomass moisture content. Hammer mill grinding of biomass with a large screen size (31.75 mm) resulted in high energy consumption and low throughput during briquetting. The increase in moisture content decreased the total energy consumption and increased the throughput of the briquetter. Briquette densities were of consistently higher value when biomass samples were compressed at a lower moisture level. The moisture content and hammer mill screen size indirectly influenced the briquette densities by affecting the pressure and residence time in commercial briquette production. Briquettes were successfully formed without adding a binder.     

生物质成型燃料循环流化床燃烧试验研究

在0.15 MW循环流化床试验台上,进行了玉米秸秆和苹果树枝成型燃料燃烧特性以及排放特性的试验研究.试验结果表明,玉米秸秆成型燃料和苹果树枝成型燃料在循环流化床中能够稳定燃烧,燃烧效率达到96.8%;尾气中HCl的排放质量浓度较高,SO2的排放质量浓度随着生物质的硫含量增大而增大;使用选择性炉渣作为床料同时加入黏土作为添加剂的方法,能够有效抑制玉米秸秆成型燃料和苹果树枝成型燃料燃烧过程中床料的黏结,黏土对循环流化床的物料循环流化起到了稳定作用.     

生物质成型燃料技术及应用前景

分析了现国内生物质电厂集中存在的燃料问题,而生物质成型燃料能够解决秸秆运输、储存、防火等问题,具有广阔的发展前景。对比介绍了生物质成型技术,分析生物质成型燃料的燃料特性。结果表明,生物质成型燃料可以改善燃烧特性,燃烬时间长,有利于提高生物质灰熔点。     

秸秆类生物质压块棱角撕裂倒钝过程数值分析

针对生产过程中出现的压块成型设备模孔边角处堵塞原料造成压块棱角撕裂倒钝现象的形成机理进行研究,运用FEA分析软件ANSYS11.0模拟成型过程中原料的流动与塑性形变过程并通过试验对比研究,为压块成型设备结构优化提供技术依据。