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.     

Characteristics of some biomass briquettes prepared under modest die pressures

Biomass material, including sawdust, rice husks, peanut shells, coconut fibres and palm fruit fibres, was densified into briquettes at modest pressures of 5–7 MPa using a piston and die type of press. The briquettes were tested to evaluate their relaxation behaviour, mechanical strength and burning characteristics. The sawdust briquettes were found to have better overall handling characteristics. But briquettes of different biomass materials required different optimum conditions of fabrication and generally showed a promising potential for further development.     

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.     

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%。     

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.     

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.     

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.     

Effect of a mild torrefaction for production of eucalypt wood briquettes under different compression pressures

The heat treatment of wood (i.e. torrefaction) followed by densification of wood particles (e.g. by briquetting) may be used as a process to improve homogeneity and energy properties of wood for use as a solid fuel. The wood of Eucalyptus grandis and Eucalyptus spp. were treated at 180, 200 and 220 °C for 60 min under a nitrogen atmosphere. Briquettes were produced with untreated and heat-treated wood particles using 120 °C, for 7 min pressing and 6 min cooling time, under pressures of 6.9, 10.3 and 13.8 MPa. The briquetting compacting pressure showed no significant influence on the briquettes properties. Briquettes density was similar for all cases presenting 1.14 g cm⁻³ for Eucalyptus spp. and 1.06 g cm⁻³ for Eucalyptus grandis wood. A mild torrefaction of the wood at 200–220 °C increased the potential energy of the particles and briquettes, showing an improvement in their density, dimensional stability and hygroscopicity. Briquettes produced from heat-treated Eucalyptus spp. wood presented higher energy density (24.79 GJ m⁻³) at 200°C-treatment when compared with untreated wood (20.76 GJ m⁻³). Regarding E. grandis, briquettes produced with heat-treated (200 °C) particles showed only a marginal higher energy content than with untreated wood, 21.70 GJ m⁻³ and 21.38 GJ m⁻³, respectively. The two eucalypt woods showed differences regarding the heat treatment and briquetting, pointing out that the optimization of these processes should be specific for each species. However, a mild torrefaction of the wood particles decreased the differences between materials which might be useful as a process to increase feedstock homogeneity when using mixed raw-materials.     

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.     

Adapted hyacinth briquetting machine for mass production of briquettes

Detailed design and development of an adapted briquetting machine is presented to help optimize time and energy expended in the production of briquettes locally. The machine is designed specifically to convert waste materials into useful briquettes. This research focused on the development of a modified automated briquetting machine with hopper, grinder, and heating element attached. This has eliminated the deficiencies of the classical briquetting machine developed. The machine is modified such that grinding, compacting, and heating processes are carried out simultaneously thereby minimizing tardy time and increasing productivity by producing solid briquettes ready for immediate use. The essential features of the machine are the hopper, the screw shaft, and die and electric motor of 1horsepower with a design speed of 2830rpm. It is fast, easy to operate, and safe to use. The efficiency of the machine was deduced to be 90% with a production rate of 72 g/h and power consumed at 1.3 kW. The briquettes produced from the developed machine is a blend of hyacinth plant and groundnut shell with waste oil and starch as a binder. The briquette fuel produced can be used as solid fuels in local bakeries, restaurants, and domestic and industrial settings.     

A techno-economic evaluation of biomass briquetting in India

A financial analysis of biomass briquetting technology in India has been undertaken. Simple cost functions for briquetting machines have been developed. Unit cost of briquette production for various types of raw materials and different capacities of briquetting units have been calculated. Role of different factors affecting the cost of production of briquettes have also been analysed.     

Biomass briquetting and its perspectives in Brazil

A study of the status of biomass briquetting and its perspectives in Brazil was conducted including determination of the availability and characteristics of the agro-residues for briquetting. Wood residues, rice husk and coffee husk were characterized and identified as the more promising agro-residues for briquetting in the short-term in Brazil. A survey was carried out in order to determine the number of briquetting factories in Brazil, and also to determine: used briquetting technologies, briquettes production, briquettes sale prices, the status of biomass briquetting market and its future perspectives.     

Effects of raw material particle size on the briquetting process of rice straw

Biomass feedstocks need to be milled or chopped into particles before briquetting, and the particle size has great effects on the energy consumption and product quality. In this study, the effects of the particle size on the rice straw briquetting process were investigated. The raw materials were milled or chopped into four different sized test materials. Experiments were carried out with an electronic universal testing machine and a self-designed single pellet unit on the basis of a simplex-centroid design. Several parameters, including briquetting time, energy consumption, maximum extrusion force, product compressive strength, and product density, were tested and recorded. The experimental data were processed by the methods of regression analysis and variance analysis. Finally, effects of raw material particle size on the briquetting process, energy consumption, maximum extrusion force, product compressive strength, and product density were obtained. Results showed that, compared with simple sized materials, mixed materials achieved lower energy consumption, higher product compressive strength, and higher product density.     

Key techniques and parameters for briquetting corn stover sprayed with biogas slurry in a cold region in China

Densification of biomass is often necessary to combat the negative storage and handling characteristics of these low-bulk-density materials. Corn stover is an important feedstock being considered for production of renewable fuels and energy in China. Densification of corn stover would help reduce the problems and costs of bulk transportation, handling, and storage of biomass feedstock. In cold regions, some thermosetting binder will be added when briquette fuel is made with corn stover because of its high water and lignin content. It is important to understand the synthesis mechanism of thermosetting binder under certain temperature and pressure combined with strong alkaline slurry to explore develop ment of a new process of briquetting corn stover based on only alkaline slurry as an environment-friendly binder. In this study, flat-die briquetting machine has been used with a cone-shaped press roller, and a matching die hole on the press plate. At the same time, orthogonal experiments were designed from the results of single-factor experiments to obtain optimal briquetting conditions. The effects of spray quantity of biogas-slurry, size of die hole, and water content of corn stover on the durability and bulk density of corn stover briquettes were investigated. Moreover, the model for whole factors and the model for interaction between factors for indexes have been built, emulated the optimum processing parameters. The results show briquettes of corn stover with durability of 83.33% were produced when the spray liquid flow quantity of biogas-slurry, size of die hole, and water content of corn stover were 0.45 L/kg, 28 mm, and 20%, respectively. Bulk density of 616 kg/m³ was produced when the spray liquid flow quantity of biogas-slurry, size of die hole, and water content of corn stover were 0.3 L/kg, 24 mm, and 25%, respectively. These results have been checked by verification testing. The successful implementation of this project provides theoretical support and test instruction for the development of green biomass energy for sustainable development.     

A new binder in production of water-resistant briquettes from bituminous coals: Co-polymer binder

Briquetting could be a solution to economic and environmental problems regarding fine coals. However, briquettes that are formed using molasses disintegrate in water and create problems. Providing water resistance to briquette, bitumen and asphalt are illegally used, however they generate more air pollution. In order to resolve this negative situation, a new binder with a co-polymer origin, Mowilith-VDM^©, is tested for briquetting of bituminous fine coals. The results of tests have shown that class I type (TSE, 1996) water resistance briquette can be produced using the co-polymer binder percent of 8, a drying temperature of 100°C, a drying time of 15 min, and a pressure load of 29.5 MPa.     

Using cotton plant residue to produce briquettes

In Arizona, cotton (Gossypium) plant residue left in the field following harvest must be buried to prevent it from serving as an overwintering site for insects such as the pink bollworm. Most tillage operations employed to incorporate the residue into the soil are energy intensive and often degrade soil structure. Trials showed that cotton plant residue could be incorporated with pecan shells to produce commercially acceptable briquettes. Pecan shell briquettes containing cotton residue rather than waste paper were slightly less durable, when made using equivalent weight mixtures and moisture contents. Proximate and ultimate analyses showed the only difference among briquette samples to be a higher ash content in those made using cotton plant residue. Briquettes made with paper demonstrated longer flame out time, and lower ash percentage, compared to those made with cotton plant residue.     

Experimental study of the influence of lime and clay on the combustion efficiency of honeycomb briquettes

The influence of lime and clay on the combustion efficiency of honeycomb briquettes was studied. The experimental results showed that the combustion efficiency of the briquettes varied with the types and content of inorganic additives. When the content of inorganic additives was lower than 14%, the combustion efficiency of the briquettes was higher (> 98.8%), and the influence of clay on the combustion efficiency of the briquettes was slightly less than that of lime. When the content of inorganic additives was more than 14%, the combustion efficiency of the briquettes with clay was reduced rapidly as the clay content grew and was much less than that with lime.     

Briquetting of palm fibre and shell from the processing of palm nuts to palm oil

Malaysia is the major producer of palm oil in the world. It produces 8.5 million tonnes per year (8.5×10⁶ ty⁻¹) of palm oil from 38.6×10⁶ ty⁻¹ of fresh fruit bunches. Palm oil production generates large amounts of process residues such as fibre (5.4×10⁶ ty⁻¹), shell (2.3×10⁶ ty⁻¹), and empty fruit bunches (8.8×10⁶ ty⁻¹). A large fraction of the fibre and much of the shell are used as fuel to generate process steam and electricity in the palm processing mill itself. However, much is wasted by pile burning in the open air with attendant air pollution, dumped in areas adjacent to the mill, or utilized as manure in the palm oil plantation. In this paper, an attempt has been made to convert these residues into solid fuel. The palm shell and fibre is densified into briquettes of diameter 40, 50 and 60 mm under moderate pressure of 5–13.5 MPa in a hydraulic press. Experiments are carried out to determine density, durability, impact and compressive strength of the briquettes. The heating value, burning characteristics, ash and moisture content are other objects of the study. A relationship between press pressure and the briquette density has been established. The produced briquettes have densities between 1100 and 1200 kgm⁻³. The briquettes properties are quite good with good resistance to mechanical disintegration, and will withstand wetting. The gross calorific value is about 16.4 MJkg⁻¹ (maf), and the ash content is about 6% and the equilibrium moisture content is about 12%. Further work is required to acquire complete understanding of the densification process before good quality and durable briquettes could be made free from cracks.     

Upgrading of biomass by means of torrefaction

We present results on upgrading of wood and briquettes by means of torrefaction. The torrefied products showed significantly less smoking during combustion and a relatively faster rate of combustion. The weight and energy yeilds of torrefied wood are 66.7–83.3 and 76.5–89.6%, respectively; the corresponding values for sawdust briquettes are 76.3–93.8 and 83.1–95.3%, respectively.     

利用造纸废液制作小麦秆成型燃料的试验研究

对掺混造纸废液制作小麦秆成型燃料的主要影响因素进行了成型试验研究,试验研究与分析了在不同废液浓度下施加压力、废液掺加比例、原料粒度等因素对致密成型的影响规律,比较了分别掺相同比例的废液与水的成型试验。通过检验成型状况,找出使小麦秆致密成型的合理压力、含水及含废液率范围、最佳的原料粒度。试验研究结果表明：在相同粒度和施加压力下,掺废液的成型物密度高于掺同样比例水的成型密度,在原料粒度0~15 mm、压力75 MPa、含废液率15%和废液浓度50%的情况下,小麦秆成型效果较好。