Strength Of Briquettes Research Articles

Ocena wytrzymałości mechanicznej brykietów na bazie drobnoziarnistych frakcji węglowych pochodzących z procesu wzbogacania węgla

Ocena wytrzymałości mechanicznej brykietów na bazie drobnoziarnistych frakcji węglowych pochodzących z procesu wzbogacania węgla

Research on the Post-reaction Strength of Iron Coke Hot Briquette Under Different Conditions

The utilization of iron coke hot briquette (ICHB) prepared by carbonizing iron ore–coal composite agglomerate made from hot-pressing the mixture of iron ore and blended coal has been considered to be an effective countermeasure to improve blast furnace ironmaking reaction efficiency and to reduce carbon emissions. The strength of ICHB after gasification reaction is overestimated by the Chinese National Standard (GB/T 4000/2008, equivalent to the Nippon Steel Corporation method) and should be evaluated by different methods. In this study, the post-reaction strength of ICHB with the addition of different ratios of iron ore under various conditions was experimentally investigated to illuminate the degradation mechanism of ICHB reacted with CO2. The results showed that, with increasing the iron ore addition ratio from 0% to 20%, the reactivity of ICHB reacted with CO2 at 1100°C for 2 h is remarkably increased, due to the catalytic effect of metallic iron in ICHB, while the post-reaction strength is distinctly decreased. Furthermore, stopping at the weight loss ratio of 20%, the strengths of ICHB after reaction at 1100°C under a CO2 atmosphere and a CO2/CO=1/1 atmosphere are clearly reduced, from 89.74% to 75.93% and from 85.24% to 73.65%, respectively. Meanwhile, the post-reaction strength of ICHB under CO2 is greater than that obtained under CO2/CO=1/1 atmosphere, since there is more time for the reaction gas to diffuse from the exterior to the interior of the ICHB under the latter condition. Additionally, the post-reaction strength of ICHB decreases with increasing weight loss ratio regardless of the reaction gas composition; however, it can be maintained at a high level.

Influence of Preparation Process on Briquette and Form Coke Compressive Strength

This paper investigated preparation process of briquette by using starch and bentonite as composite binder. It also studied the impact of pulverized coal particle size, coking particle size, compacting pressures, moisture content on the strength of briquette and form coke. The result showed that coking coal particle size was the main influence factor. And the optimum conditions of molding process were as follows: low rank pulverized coal particle size was less than 0.63mm, coking coal particle size was less than 0.28mm, compacting pressure was 60 kN, molding moisture content was 12%. Under the optimal conditions, compressive strength of briquette and form coke was 3470 N/ball and 2910 N/ball, respectively.

Densification of Thermally Treated Energy Cane and Napier Grass

Densification of thermally treated energy crops by torrefaction is required to increase the bulk density and to reduce the handling, transport, and storage cost for bioenergy applications. In this study, we investigated the densification characteristics of thermally treated energy cane and napier grass grown on marginal lands at various applied forces and binder levels. The addition of starch (0, 10, and 15%) and lignosulfonate (0, 5, and 10%) was examined to enhance the strength and durability of raw and torrefied briquettes, respectively. Although the use of starch binder relatively increased the bulk density, it did not improve the hardness and durability of untreated energy crop briquettes. The addition of 10% lignosulfonate binder increased the torrefied briquette density of up to 11% for energy cane and up to 38% for napier grass and decreased the compression energy by up to 35% for both samples. Moreover, the hardness (compressive resistance) was tripled, and the durability was relatively improved for both torrefied briquettes. The increase in applied force not only increased the bulk density but also increased the specific energy required for densification. However, there was no substantial change in hardness and durability when the compression force was increased from 15 to 20 kN for all samples. In overall, densification of thermally treated energy crops is required, and the quality of the briquettes can be improved by the use of appropriate binders for efficient handling, transport, and storage.

Briquetting of Pine Needles (Pinus roxburgii) and Their Physical, Handling and Combustion Properties

Valorization of pine needles by producing briquettes and identification of optimum levels of densification process parameters based on physical, handling and combustion properties. Experiments were conducted based on orthogonal array test with 16 sets of experiment for 4 levels of 3 independent parameters, size of pine needles, densification pressure and temperature. The briquettes of 35 mm diameter were prepared using a steel mould with well smashed pine needles at 10% (wet basis) moisture content. The dependent parameters were, change in volume, density, durability and compressive strength of briquettes. Grey relational analysis was conducted to identify the optimum levels of independent parameters that minimized the percent change in volume and density of briquettes, and maximized the durability and compressive strength. Grey relational grade that gave equal importance to all the dependent parameters was used as the index for the identification of optimum solution. The pine needles of particle size less than 2 mm, pressure of 9 MPa and temperature of 150 °C was found to be optimum for the production of briquettes, with densification pressure having the highest influence on quality of briquettes. The briquettes produced had calorific value of 17.56 MJ kg−1, density of 1228 kg m−3 and compressive strength of 7.05 MPa. The briquettes were used in an updraft gasifier to generate producer gas which had calorific value of 4.24 MJ Nm−3. It took 12 min to produce flammable gas. The gas from the gasifier can be burnt using specially designed burners in furnaces. The optimum briquetting process parameters identified can be used for the large scale production of briquettes from pine needles at the industrial scale. This will add value to the pine needles, and reduce the risk of forest fire, carbon emissions, greenhouse gas effects and the environmental pollution to a great extent.

Effect of different binders on Mechanical properties of iron flotation concentrate briquettes

The effect of different binders on compressive strength and shatter resistance of flotation iron concentrate briquettes was investigated. Binders used were bentonite, lime, bituminous coal and cellulose. The Haematite concentrate was obtained by reverse flotation of fluorspar tailings. Characterisation of the iron concentrate was done and various operating parameters on the briquetting of the iron concentrate was investigated. The results showed that 80% of the tailings particles were - 150µm in size and major mineral phases are haematite, quartz and calcium tecto-dialuminodisilicate. The iron concentrate briquettes started forming at a concentration of 9% weight for all binders. Bentonite and cellulose briquettes showed compression strength above 650 KN/m2 at room temperature whilst lime and coal gave compressive strength of 185 and 40 KN/m2 respectively. Compressive strength of bentonite and cellulose briquettes decreased to 550 and 265 KN/m2 respectively after heating the briquettes at 1000°C whilst that of lime and coal to 0 KN/m2. Cellulose binder gave briquettes with higher shatter resistance of around 100% at temperatures between 25°C and 200°C. For temperatures above 200°C, bentonite gave better results.

Binderless briquetting of lignite by the mechanical thermal expression process

ABSTRACTThe mechanical thermal expression (MTE) process, which has been widely studied as a dewatering technology, could also be used for the briquetting of lignite. In this study, the effect of operating conditions on the compressive strength and shatter index of briquette produced by the MTE process was investigated. The compressive strength of briquette increased with the increase of pressure and temperature. The increase in pressure and temperature also resulted in a decrease of residual moisture content in briquettes, which had a positive effect on the compressive strength and shatter index. It was demonstrated that the briquettes produced by the MTE process could survive handling and transportation. The dewatering of lignite during the MTE process strengthened the bond between particles, which enhanced the compressive strength of briquette. The presence of humic acid and functional groups, such as carboxyl and hydroxyl, enhanced the compressive strength of briquette by promoting the formation of hydrogen bonds between the surfaces of lignite particles. The combustion efficiencies and particle emission of lignite could be improved by the MTE briquetting process.

Influence of the Type of Mixture and Concentration of Different Binders on the Mechanical Properties of “Green” Charcoal Briquettes

The application of biomass to generate energy has been highly studied as an alternative to fossil fuels. In Brazil, there is a large production of orange juice, and their solid waste (bagasse) has as its main destination the production of food for ruminants. Therefore, there is an interest among the industries to transformed this waste into a by-product with higher benefit. In this way, this work has as main objectives, the use of a new type biomass to produce “green” charcoal and the application of three different types of binders (industrial cornstarch, pectin with high degree of esterification and pectin with low degree of esterification) using three different proportions (5, 10 and 15%) and two types of mixtures in way to verify which briquette has the lowest friability index a better compression resistance. To determine the friability index, the tumbling method was applied. The compressive strength of the briquettes was also determined. The binder that brought better characteristics to the charcoal briquettes, and therefore would be chosen for a production line is the industrial cornstarch. For this binder, the briquettes showed higher mechanical strength when applied the second mixing method. In this case, the briquette with a composition of 10 % of industrial cornstarch, presented characteristics as non-friable and withstand a pressure of 4.093 MPa in the compression tests. The choice of this binder is also because it is cheaper among the three tested ones.

Bio-Oil and Biochar Derived from the Pyrolysis of Palm Kernel Shell for Briquette

The objective of this study was to produce briquette from the mixture of pyrolysis products. Palm shell was pyrolyzed at a temperature of 400°C for 2 h holding time and heating rate of 10°C/min. The biochar and bio-oil ratio was prepared at 3:1 weight percentages for briquette. The viscosity of bio-oil was improved to increase the bonding forces. The characterization of biochar, bio-oil, coal and briquette were analyzed and presented in this study. The density and compressive strength of briquette were, respectively, found to be 0.94 gcm-3 and 3.20 Nmm-2. The shatter and water resistance of briquette were established to be 97 and 96 wt. %, respectively. The high heating value (HHV) of briquette was 29.6 MJkg-1 greater than that of Malaysian sub-bituminous coal 24.6 MJkg-1. It implies that the briquette produced is stable, durable and qualitative. Therefore, it can be concluded that the briquette can substitute coal in some applications.

Energy and Resource-Saving Sources of Energy in Small Power Engineering of Siberia

The sustainable development of distant areas of Siberia is associated with the structures of energy demand and supply, the implementation and promotion of the process of environmentally safe restructuring of the energy supply system. It has been established that suspension coal fuels derived from brown coal, coal mining, coal processing wastes can be used as fuel. The results of experimental and industrial boilers on suspension water coal fuel are presented. The designs of vortex combustion chambers of various powers are developed and tested. The possibility of using coal-enrichment wastes and substandard coals for the production of manure-coal fuel briquettes was studied. It is shown that the strength and thermal power characteristics of briquettes depend on the moisture content and degree of metamorphism of the raw materials. The most effective percentage of the solid phase and manure, as a binder, was determined.

Coal tar pitch and molasses blended binder for production of formed coal briquettes from high volatile coal

High volatile coal fines do not meet the requirements of various industrial production processes and cause large resource losses. Recycling coal fines by the production of formed coal briquettes has a great realistic significance in saving coal resources and protecting the environment. In order to utilize high volatile coal fines to produce coal briquettes as a substitute for COREX ironmaking process, thermal behaviors of coal, coal tar pitch and briquettes were analyzed. A blended binder composed of pitch and molasses was obtained and ventilation drying was applied to strengthen their bonding strength. Microstructure and composition of briquettes were tested by SEM and EDS. Results showed that both volatilization and carbonization of briquette should be processed in protecting atmosphere because of coal's low combustion temperature at 351°C. The strengths of cured and carbonized briquettes are weaker than dried briquettes because of coal's violent volatilization which causes vast pores and loose structure in briquettes. Molasses can significantly improve the strength of dried briquettes. Ventilation drying with short time provides briquettes with higher strength than static drying. By adding 15% blended binders (pitch: molasses=13:2), drop resistance of green briquettes reaches 19.4 times/2m. After drying at 130°C for 1h with a gentle air flow of 1.2m/s, drop resistance and compressive strength of dried briquettes are up to 56.6 times/2m and 13.06MPa, respectively. The briquettes consist of primarily C, a small amount of O and very small amounts of Al, Si, Ca, S and Fe. The strength and composition of briquettes favorably meet the requirement of COREX ironmaking process.

An investigation on the performance of sawdust briquette blending with neem powder

This paper discusses the performance of the sawdust and neem powder briquette and its blends. In the first set of experiments, the sawdust and neem powder briquettes are produced by manually operated hydraulic pelletizer in the pressure range of 7–33MPa. The strength of briquettes is investigated by the shatter index, impact resistance, durability index and water resistance test. The calorific value and water boiling tests have been also conducted to study the performance of the briquettes. The result shows that the neem powder briquette has significantly higher strength, but lower calorific value compared with the sawdust briquette. Also the performance of the briquettes increases with increase in pressure. Thus the maximum pressure of 33MPa is used for the second set of experiments. In the second set of experiments, the neem powder is blended with the sawdust in the ratio of 100:0, 75:25, 50:50, 25:75, 0:100 (Sawdust:Neem powder). The study shows that the sawdust with neem powder as binding agent has considerably increased the strength of the briquette with a little reduction in burning rate.

Characterization of ground slag and borax waste and their effects on the compressive strength of briquettes

The usage of briquettes is preferred in the construction industry for many years. The quality of briquettes is directly related with characteristic features of raw materials and their compositions, production procedure, firing method, temperature and duration. There are waste materials such as borax waste having been used for briquette production, however it is not available to combined of both borax and ground slag used in briquette production. In the study, both borax and ground slag were used together as an additive in order to observe effects on the material characteristics of briquette samples. In this scope, compressive strength and bulk density of the samples produced using borax and ground slag were defined. Moreover, SEM-EDS, XRD and DTA/TG analyses of the materials were carried out and discussed. The overall results have concluded that not only higher compressive strength results were obtained using these wastes, but also the usage of waste up to 22% ratio was provided for this study. Consequently, it is determined to be possible using borax waste and ground slag in briquette production.

The Strength and Density of Green and Reduced Briquettes Made with Iron Ore and Charcoal

Composite briquettes or pellets consisting of iron ore, carbon, and a binder are a source of direct reduced iron (DRI). In the handling of green and reduced briquettes, high strength is important to minimize briquette breakdown. The use of charcoal as a source of carbon, rather than coal provides a way of introducing renewable carbon into the ironmaking process. Composite briquettes were made with Australian hematite iron ore, low volatile charcoal and 2 % starch as a binder. The carbon-to-iron mass ratio was varied between 0.18 and 0.26. The green briquettes were heated to either 1300 or 1350 °C for times varying from 3 to 15 min. After heating, the briquettes were tested for compressive strength, density, and the degree of iron metallization. The aim of the work was to determine the key strength forming features of the briquettes during heating and reduction. Dried green briquettes, made with a starch binder, were found to be very strong and required a force of at least 3800 N to yield under compression. After heating for 3 min, the briquettes lost strength rapidly before regaining strength at longer heating times of 10 and 15 min. Increasing the C/Fe ratio in the briquette mix decreased the strength and density, and increased the iron metallization of the heated briquettes. Briquette strength also increased with increasing time from 10 to 15 min and heating temperature from 1300 to 1350 °C. These observations can be explained in terms of the distance between iron oxide particles in the briquette mix. At low C/Fe ratios, iron oxide particles will be relatively close together which facilitates the development of a connected slag network which acts as a binder and increases briquette strength.

Assessment of Physical Properties of Briquettes Made of Mixtures of Selected Plant Raw Materials and Post-Fermentation Waste

Abstract Searching for renewable energy sources causes the increase in the interest in obtaining and processing of plant biomass for energy purposes. One of the methods of using biomass is to converse it into solid biofuels in the form of briquettes. The research covered briquette production with the use of the following plant raw materials: straw of spring crop mixture (wheat with barley – 50/50%) and oat straw and post-fermentation waste. Samples of fragmented straw with addition of post-fermentation waste were prepared in three various weight participation i.e.: 90/10%, 80/20% i 50/50%. The paper presents an assessment of physical properties of briquettes manufactured from the investigated mixtures of plant raw materials with an addition of post-fermentation waste in the hydraulic piston briquetting machine. We determined the moisture of raw materials and waste, length, diameter and mass of manufactured briquettes as well as their specific density and mechanical strength. We found out that along with the increase of the mass participation of post-fermentation waste in the accepted mixtures of plant materials from 10 to 50% their length increased from 5 to 25% and the mass from 1 to 12%. On the other hand, specific density of briquettes increased from 18 to 24% for grain mixtures and from 3 to 7% for oat straw. Mechanical strength of briquettes was within 88.3-90.6% for grain mixture and 83.6-87.1% for oat straw.

Influence of binders on physical properties of fuel briquettes produced from cassava rhizome waste

Investigations were undertaken to produce fuel briquettes from cassava rhizome waste with five binders namely molasses, starch gel, concentrated slop, cassava pulp and soybean residue at the ratios of 6:4, 7:3, 8:2, 9:1 and 10:0. Physical properties viz. density, compressive strength and impact resistance index of briquettes showed gradual improvement with the increased amount of binders. Briquettes produced from cassava rhizome charcoal with molasses, starch gel and concentrated slop as binders in proportion of 6:4 and 7:3 yielded higher density ranging from 0.69 to 0.91 g cm−3, compressive strength from 8.51 to 14.94 kg cm−2, impact resistance index from 153.7 to 416.7 and calorific values from 21,670 to 24,367 KJ kg−1, respectively. From economic analysis, it was found that briquettes produced from cassava rhizome charcoal with either molasses or starch gel binder in proportion of 7:3 were found best with highest BCR of 2.01 and 2.15, respectively.

Production and Physical-Mechanical Characterization of Briquettes from Coconut Fiber and Sugarcane Straw

Biomass in a broad sense has a great energy potential. It can be densified improving the logistic and the energetic efficiency. The aim of the present work was the characterization of coconut fiber (FC) and sugarcane straw (PC) and the evaluation of mechanical properties of the briquettes produced from these materials. The samples of materials were performed to proximate analysis and high heating value (HHV) with three repetitions. Five different blends were tested with 15 repetitions for each blend: treatment T1 (100% FC), T2 (75% FC and 25% PC), T3 (50% FC and 50% PC), T4 (25% FC and 75% PC) and T5 (100% PC). It was used particles size smaller than 0.84 mm with 12% moisture content for the briquettes production. The process was done in a hydraulic press without heating or binder. Briquette length expansion at specific time intervals was determined over a 72 hours period. The strength and friability of briquettes were measured after the production period of six days. The results showed that in the proximate analysis and HHV coconut fiber and sugarcane straw presented 74.01% and 77.50% for volatile matter, 3.71% and 5.68% for ash, 22.28% and 16.81% for fixed carbon, 18.24 MJ.kg -1 e 17.49 MJ.kg -1 for HHV, respectively. Sugarcane straw briquettes were classified as very crumbly. However, blending coconut fiber with sugarcane straw improved the quality of briquette.

인도네시아 저등급석탄의 무결합제 성형 특성

저등급석탄을 건조하고 무결합제로 성형하는 경우에 대한 조건별 특성 연구를 수행하였다. 인도네시아 산 두 종류의 저등급석탄을 전기오븐에서 건조시킨 후 성형에 사용하였으며, 석탄의 수분별, 입도별, 성형압력별, 보관일수별로 압축강도를 측정하여 성형특성을 비교하였다. 석탄의 수분별로는 10~15 wt%에서 가장 높은 강도를 나타내었으며, 석탄의 종류에 따라 가장 높은 강도를 갖는 수분 함량의 차이가 있었다. 석탄의 입도는 적을수록 높은 강도를 나타내며 입도가 증가할수록 수렴하는 경향을 나타내었다. 성형압력이 높아질수록 성형 강도가 높게 나타났으나, 약 300 kN 이상에서는 크게 차이를 보이지 않았다. 보관일수별로는 약 일주일 동안 강도가 급격히 감소한 후 수렴하는 경향을 보였다. 이상의 결과는 저등급석탄의 산지에서 고품위화시킨 석탄을 국내 반입하는 경우에 대한 성형석탄 제조 및 관리의 지침으로 활용될 수 있다. The characteristics of binderless briquettes for dried low-rank coal was studied in this work. Two kinds of Indonesian coals were used to briquette after drying them in electric oven. The characteristics of briquettes have been examined by moisture contents, particle size, hydraulic force, and storing period. The optimum moisture contents of briquettes were observed at between 10 wt% and 15 wt%. The strength of coal briquette was stronger as particle size became smaller. The strength of coal briquette was proportional to the hydraulic force under 300 kN, whereas there was little difference among the briquettes made at more than 300 kN of hydraulic force. The strength of briquettes sharply decreased for a week after produced, and then showed the tendency of converging. The results from this work can be a useful guideline of manufacturing and managing upgraded coal briquettes.

Effects of operating variables on durability of fuel briquettes from rice husks and corn cobs

Biomass densification processes increase fuel energy density for more efficient transport. This study presents new data to show that blending different types of biomass improves the properties of densified biomass briquettes. The specific objectives were to investigate the effects of sample batch (biomass source), material ratio (rice husks to corn cobs), addition of binder (starch and water mixture) and compaction pressure, on briquette properties, using a factorial experiment.Briquettes had a unit density of up to 1.9 times the loose biomass bulk density, and were stronger than briquettes from the individual materials. Considering average values from two biomass sources, an unconfined compressive strength of 176kPa was achieved at a compaction pressure of 31MPa for a 3:7 blend of rice husks to corn cobs with 10% binder. These briquettes were durable, with only 4% mass loss during abrasion and 10% mass loss during shattering tests. They absorbed 36% less water than loose corn cobs. Statistical analysis of the results showed that starch and water addition was required for adequate briquette strength, but significantly reduced green and relaxed densities. The source of the biomass had a significant effect on densification, which emphasises the need to understand factors underlying biomass variability.

Optical microscopy analysis of briquette binders

Environmental requirements and demands from the coal industry have resulted in a boom in briquetting technology in China. In this work, a low-volatility bituminous coal from the Changcun mine and bentonite binders are used for briquetting. The compressive strength, impact strength, and thermal stability of briquettes made using different binder concentration are determined. The morphology and distribution of binders in briquettes are studied by optical microscopy and digital image-processing technologies. The concept of roundness is introduced to indicate the pressure to which the binders are subjected during briquetting. The influences of binder morphology on briquette strength are discussed. The binders are mainly in aggregated and dispersed forms, present in similar proportions in the briquettes. Aggregated binders with large differences in size are not well-distributed. Binder roundness values are concentrated between 1.5 and 4.0, which indicates that most aggregated binders are compressed and conform well to the surfaces of coal particles. A few binders had roundness value approximating 1 or above 4, which indicated that these were under little pressure or overloaded, respectively. The relationships between briquette strength and binder morphology show that aggregated binders are detrimental to mechanical strength while dispersed binders benefit briquetting.