Composite Briquettes Research Articles

Comparative Study on the Development of Composite Briquette as Alternative Fuel using Rice and Maize Husk

In this study, the development of briquettes from agricultural waste mainly rice and maize husk is presented. A 0.12 kg of each sample with a combination ratio of 1:1 was used in the buildup. The results obtained shows that, rice husk, maize husk and the combination of rice and maize husk have calorific value of 15.27 kJ/kg, 17.13 kJ/kg and 16.20 kJ/kg, moisture contents of 78.8 %, 86.8 % and 79.1 %, ash contents of 39.74 %, 18.07 % and 13.39 % and densities of 1084.3 kg/m3, 1011.5 kg/m3 and 1012.4 kg/m3 respectively. The research shows that briquette made from maize husk has the highest calorific value that can meet domestic use as an alternative fuel compared to briquttes from rice husk and the combination of rice and maize husk.

Experimental and Numerical Investigations on Charging Carbon Composite Briquettes in a Blast Furnace

In the present research, charging carbon composite briquettes (CCB) in a blast furnace (BF) was investigated. The CCB used contained 29.70 wt.% Fe3O4, 39.70 wt.%, FeO, 1.57 wt.% iron, 8.73 wt.% gangue, and 20.30 wt.% carbon. Its reaction kinetics in BF was examined by nonisothermal tests and modeled. Thereafter, the influence of replacing 10% ore with CCB on BF performance was studied by numerical simulations. Results showed that the CCB reaction behavior in BF could be modeled using the previously proposed model under ags = 1900 m2·m−3. Numerical simulations on a BF with a production of 6250 t hot metal per day (tHM/day) showed that replacing 10% ore with CCB efficiently improved the BF operation for coke saving. In the CCB charging operation, the CCB reached a full iron-oxide reduction above the cohesive zone (CZ) and a carbon conversion of 85%. By charging CCB, the thermal state in the BF upper part was significantly changed while it was not influenced in the BF lower part; the ore reduction was retarded before the temperature reached 1073 K and was prompted after and the local gas utilization tends to increase above the CZ. By the CCB reduction above the CZ, BF top gas temperature was decreased by 8 K, the BF top gas utilization was increased by 1.3%, the BF productivity was decreased by 17 tHM/day, the coke rate was decreased by 52.2 kg/tHM, and ore rate was decreased by 101 kg/tHM. Considering the energy consumption of sintering and coking, charging the CCB could have a significant energy-saving and CO2-emission-reducing effect for BF iron making.

ASSESSMENT OF ECOLOGICAL AND ECONOMIC EFFICIENCY OF COMPOSITE FUEL PRODUCTION FROM THE PEAT AND BIOMASS

The goal of investigation was assessment of environmental impact and economic efficiency of composite briquette production on the base of peat and renewable biomass. Biomass for composite briquettes was obtained from straw (cereal crops and rape) and wood residues (sawdust, chips) Experimental composite briquette were produced from the mixture of peat and biomass in relation to – 25 : 75, 50 : 50, 75 : 25. The technological cards of biomass feedstock production for 6 variants were developed. Technological cards were used for calculation of emission into the atmosphere during life cycle of biomass production and prime cost of biomass. The lowest volume of gas (SO2, NOx, CO2)
 and particulate matter (PM) emission was installed for biomass production from the sawdust. The highest volume of
 emission was installed for production of biomass from the straw with pressing it in standard bale. The volume of CO2
 emission for the sawdust production was 6 kg per ton of biomass and for the standard bale of straw was 19 kg per ton of
 biomass. Prime cost of sawdust production (lowest) was 11 belarusian rubles per ton of biomass, for the wood chips was 19 rubles per ton and for the straw varied from 26 to 33 rubles per ton in depend of technology. It was installed that
 growth of biomass rate in composite briquette had a good influence on number of basic fuel characteristics (contents of
 ash, sulfur and moisture). The variation of calorific value of briquette was not significant in depend of biomass contents.
 In accordance with assessment of all characteristics the better briquettes was obtained from the peat and sawdust.

Physical and mechanical characteristics of composite briquette from coal and pretreated wood fines

Melina wood torrefied at 260 °C for 60 min was agglomerated with lean grade coal fines into composite briquettes using pitch as binder. Torrefied biomass (3%–20%) and coal fines (80%–97%) were blended together to produce the composite briquettes under a hydraulic press (28 MPa). The briquettes were cured at 300 °C. Density, water resistance, drop to fracture, impact resistance, and cold crushing strength were evaluated for the composite briquettes. The proximate, ultimate, and calorific value analyses were carried out according to different ASTM standards. Microstructural studies were carried out using scanning electron microscope and electron probe microanalyzer equipped with energy dispersive x-ray. Fourier Transform Infrared Spectrophotometer (FTIR) was used to obtain the functional groups in the raw materials and briquettes. The density of the composite briquettes ranged from 0.92 to 1.31 g/cm3 after curing. Briquettes with < 10% torrefied biomass has good water resistance index (> 95%). The highest cold crushing strength of 4 MPa was obtained for briquettes produced from 97% coal fines and 3% torrefied biomass. The highest drop to fracture (54 times/2 m) and impact resistance index (1350) were obtained for the sample produced from 97% coal and 3% torrefied biomass. The fixed and elemental carbons of the briquettes showed a mild improvement compared to the raw coal. The peaks from FTIR spectra for the briquettes shows the presence of aromatic C=C bonds and phenolic OH group. The composite briquettes with up to 20% torrefied biomass can all be useful as fuel for various applications.

Softening–melting–dripping characteristics and evolution mechanism of vanadium-bearing titanomagnetite carbon composite briquette used as novel blast furnace burden

Softening–melting–dripping characteristics and evolution mechanism of vanadium-bearing titanomagnetite carbon composite briquette used as novel blast furnace burden

Preparation of high-strength biochar composite briquette for blast furnace ironmaking

In this research, using iron-oxide fines (average size: 2.5 μm) and biochar fines (average size: 50.0 μm), the biochar composite briquette (BCB) for blast furnace (BF) application was prepared by cold briquetting followed by heat treatment. The preparing conditions were optimized regarding its cold crushing strength. Anti-pulverization capability, reaction development, and structure evolution of the optimally-designed BCB under simulated BF conditions were then examined. Results of optimizing BCB preparation conditions showed that a heating temperature of 1073 K was optimal for preparing the BCB. The optimally-designed BCB contained 11.10 wt.% carbon, 72.21 wt.% Fe3O4, 11.25 wt.% FeO, and 0.77 wt.% Fe, 6.44 wt.% gangue, and had a cold crushing strength of 1800 N/briquette. Results of BCB behavior under simulated BF conditions showed that the cold crushing strength after partial reaction of the BCB ranged from 1500 N/briquette to 5500 N/briquette and its maximum volume shrinkage degree was 0.45. The high anti-pulverization capability of the BCB was supported by the slag matrix or the iron network. Under the simulated BF conditions, the BCB underwent five stages of reduction by atmosphere, partial self-reduction and reduction by atmosphere, full self-reduction, partial self-reduction and gasification by atmosphere, and gasification by atmosphere. It is inferred from the experimental findings that, by charging the BCB in BF, an increase of top gas utilization efficiency could be realized, and a favorable influence on lowering the temperature level of the thermal reserve zone could be obtained.

Assessing the effect of starch on density and caloric value in sawdust briquette for domestic energy utilization in North-Western Nigeria

The effect of starch on density, caloric value and specific fuel consumption were assessed in this research. Composite sawdust briquettes were produced from the mixture of sawdust and starch within four treatments in a percentage ratio of 80:20 for treatment A, 70:30 for treatment B, 60:40 for treatment C and 50:50 for treatment D. Densification of the mixtures was achieved using a manually operating briquetting machine and starch gel was used as a binding agent. The performance of briquette produced was examined under controlled cooking test. Energy content was determined using oxygen bomb calorimeter. The results obtained from density according to treatments A, B, C and D respectively were 0.0002067kg/cm3,0.0002433kg/cm3, 0.00025kg/cm3. Treatment D has the highest density of 0.00029kg /cm3. The caloric value was determined from the heat of combustion with treatment B having the highest energy content of 7.37cal/g, C=6.159cal/g, A=6.055calg, and D=4.573cal/g. Specific fuel consumption was determined during controlled cooking test and the values for the respective treatments were A=0.89g, B=0.47g, C=0.64g, D=0.86g, and fire wood=0.89g. Time taken to cook 200g of rice was obtained using wrist watch and the values were: A=50min, B=44min, C=48min, D=47min, and firewood had the highest value of 53min. Results showed that, increase in the quantity of starch led to increase in density of composites.

Interface Behavior and Interaction Mechanism between Vanadium-Titanium Magnetite Carbon Composite Briquette and Sinter in Softening-Melting-Dripping Process

As an innovative and promising BF iron-bearing burden, the vanadium-titanium magnetite carbon composite briquette (VTM-CCB) charging significantly affects the softening-melting-dripping characteristics and cohesive zone of the mixed burden. In this study, the interface behaviors between VTM-CCB and sinter were investigated by conducting interrupted softening-melting experiments to elucidate intrinsic structure evolution and interaction mechanisms. During softening, when the FC/O ratio of VTM-CCB ranges from 0.8 to 1.0, the molten slag-metal coexisting structure formed at the interface, thereby promoting the shrinking and decreasing T4 and T40. However, with increasing FC/O ratio higher than 1.0, the interface slagging and bonding would be suppressed due to the unconsumed carbon particles. During melting, the increasing of FC/O ratio would lower the FeO content and decrease the molten slag, and the interface layer transformed from molten slag-iron coexisting structure to dense metallic iron shell, suppressing the collapse of molten mixtures and increasing Ts. In the dripping process, increasing the FC/O ratio appropriately could promote the interface iron carburization and the aggregation of molten iron, thereby decreasing TD and improving the dripping performance. Besides, the VTM-CCB, acting as skeleton in the molten mixtures, could provide more gas channels to improve the permeability of packed bed. However, as the FC/O ratio exceeds 1.2, the Ti(C,N) would precipitate at the slag-metal interface and deteriorate the fluidity of molten mixtures, thereby deteriorating the gas permeability and increasing TD notably. Fully considering the softening-melting-dripping characteristics and the gas permeability, the appropriate FC/O ratio of VTM-CCB should not be higher than 1.2.

Rapid microwave-assisted reduction of ferromanganese spinel with biochar: Correlation between phase transformation and heating mechanism

The reduction of ferromanganese spinel (MnFe2O4) in microwave field using biochar as reducing agent was investigated in this study. It was found that the MnFe2O4-biochar composite briquette possessed good microwave absorption capability with microwave penetration depth less than 20 mm at 2.45 GHz, enabling its efficient self-reduction under microwave irradiation. The MnFe2O4 was initially reduced to monoxide and then transformed to metallic iron and MnO. The iron metallization degree of reduced briquette reached 90.19% under the conditions of the C/MnFe2O4 molar ratio (n(C)/n(MnFe2O4)) of 3, reduction temperature of 1050 °C, and dwell time of 15 min. The selective heating effect of microwave induced the transformation of MnFe2O4 and promoted the breaking of chemical bond between Mn and Fe based on the density functional theory analysis. The microwave heating mechanism was associated with the phase transformation in the reduction process. At low temperatures, the dielectric loss due to interfacial polarization and dipolar polarization and the magnetic loss originated primarily from natural resonance controlled the heating process. As the temperature exceeded 572.9 °C, the composite briquette had a sharp decrease of magnetic response. The formation of (FeO)x(MnO)1-x led to slight fluctuations of permittivity with increasing temperature. When the temperature was higher than 903.5 °C, the conductive loss increased dramatically because of the formation of metallic iron, which could speed up the reduction process due to the “lens effect” of microwave. Based on the combined use of microwave energy and sustainable reducing agent with a focus on the correlation between phase transformation and microwave heating mechanism, this study has validated the feasibility of the route for comprehensive utilization of spinel-structured metallurgical solid wastes, showing the bright prospect of its industrial applications.

Reaction model and reaction behavior of carbon composite briquette in blast furnace

In this research, carbon composite briquette (CCB) for BF application was prepared and had a mineralogical composition of carbon: 20.30 wt%, Fe3O4: 29.70 wt%, FeO: 39.70 wt%, Fe: 1.57 wt% and gangue: 8.73 wt%. A reaction model of the CCB in BF was developed. Using the model, the CCB reaction behavior under simulated BF conditions was explained, and the CCB reaction behavior in actual BF was predicted. Results showed that the model predictions agreed well with the experimental measurements. Under simulated BF conditions, the CCB underwent fast self-reduction in the period from 70 min (973 K) to 110 min (1273 K). In this stage, the reactions inside the CCB proceeded unevenly in the radial direction, resulting in a dense iron layer near the CCB surface. The simulation results of CCB reaction in an actual BF indicated that charging CCB in the region near the mid-radius was preferred. The CCB reaction behavior in BF could be divided into five stages: reduction by BF gas (500–850 K), partial self-reduction with reduction by BF gas (850–973 K), full self-reduction (973–1100 K), partial self-reduction with gasification by BF gas (1100–1150 K), and gasification by BF gas (>1150 K). The CCB became effective for BF energy saving after 1000 K.

Effect of Particle Sizes of Slag on Reduction Characteristics of Nickel Slag-Coal Composite Briquette

Effect of Particle Sizes of Slag on Reduction Characteristics of Nickel Slag-Coal Composite Briquette

Catalytic role of sodium carbonate in reduction of ferromanganese spinel

This present study investigated the catalytic effect of Na2CO3 on the reduction of ferromanganese spinel (MnFe2O4) using biochar as reducing agent. The reduction of the MnFe2O4-biochar composite briquettes at 1050 °C for 30 min showed that the iron metallization degree of the reduced briquettes increased from 61.1% to 84.2%, with significant decrease of initial reduction temperature due to the addition of 5 wt% Na2CO3. There also existed higher CO and CO2 concentrations in the off-gas in the presence of Na2CO3. According to the first-principles calculations, these differences were attributed to the reaction between Na2CO3 and carbon which produced oxygen vacancies on the Na2CO3 surface. These vacancies were then filled by the oxygen atoms of CO2, forming CO which was desorbed from the surface of Na2CO3 before it participated in the reduction. By creating oxygen vacancies through its reaction with carbon, Na2CO3 played a catalytic role in the reduction process.

Optimization of Composition of Selected Biomass for Briquette Production

In this study, investigations were carried out on the energy evaluation, performance analysis and optimization of briquettes produced from biomass wastes (rice-husk and sawdust) and their composites using starch and clay as binders. The proximate compositions of the briquettes were determined following ASTM analytical methods. The moisture content of rice husk and sawdust before briquettes was 20wt.% and 15wt.% respectively. The briquettes produced from bio-waste material of homogeneous particle sizes of 0.5mm and two binders of a percentage of 90:10 which were sun-dried, prepared and moisturized, were reduced to 5wt.% and compressed for the production of briquettes. The energy evaluation of the briquettes was performed using an oxygen bomb calorimeter and the performance test of the briquettes was carried out. Design Expert Central Composite Design Tool was used in the design and Response surface methodology was used to optimize the energy values of rice-husk/sawdust composite briquettes with clay and starch as binders, after which composite briquette made of mahogany sawdust/rice-husk were produced using the optimum condition values of 15% binder starch, 28% rice-husk and 9Mpa compaction pressure. The results showed that composite briquettes of mahogany sawdust and rice-husk produced with starch had a maximum energy value of 5.69kcal/g, while those made with clay had a minimum energy value of 3.35kcal/g. However, the experimental result was less than the predicted optimum value of 2%. This shows that composite briquette made from mahogany sawdust/rice-husk has better energy efficiency than other briquettes considered and it has been observed that starch is a better bonding material than clay. Briquetting technology has great potential to transform waste biomass in affordable, effective and environmentally safe, high-quality solid fuel for households and industry use.

Investigation of Metal Composite Briquette Operation in Absorption Equipment Friction Units

Reasons are considered for unsatisfactory operation of the energy-absorbing device of railway wagon drawbar, whose main element is a friction plate with special energy-absorbing cermet coating. The main specifications for the friction plate are resistance to shock loads, resistance to thermal cycles in the temperature range from ambient temperature to 850–870°C, good resistance to shear stresses, friction coefficient stability in this temperature range, lack of seizure to friction wedge material made of steel, and long operating life up to 10,000 loading cycles. According to results of metallographic studies using optical and scanning electron microscopy with energy dispersion microanalysis it is established that the poor quality of the friction plate metal composite coating is caused by the following factors: localization of eutectic containing sulfur, iron, and manganese along the “ceramic-substrate” boundary, and presence of oxide films on the surface of precursor powder particles. As a result of this excess interfaces arise in cermet material that are areas of microcrack formation during cermet operation. Thermal stresses arising during metal composite briquette manufacture lead to crack development at the interface of metal composite and a steel base. Application of unevenness to the steel base of metal composite material in a hydrogen or endogas atmosphere makes it possible to avoid both thermal cracks and subsequent metal composite separation during operation. An improvement in operating characteristics is confirmed during laboratory tests under conditions approximating operational.

Physico-mechanical Properties of Composite Briquettes from Corncob and Rice Husk

Densification of agricultural residues into briquettes as the alternative renewable feedstock can improve their physico-mechanical and storage properties as solid fuels. This paper presents the physico-mechanical properties of the composite briquettes made from corncob and rice husk. Raw samples of corncob and rice husk were collected, sorted and pulverised into fines of 0.25, 1.00 and 1.75 mm particle sizes. The fines were blended at mixing ratios of 80꞉20, 70꞉30, 60꞉40, and 50꞉50, bonded with 5% starch on weight percentage basis and compressed at compaction pressures of 25, 50, and 65 kPa to produce the briquette samples, respectively. The briquette made from 80:20 ratio of corncob to rice husk, 0.25 mm particle size and 65 kPa pressure exhibited the highest compressive strength of 111 kN/m2 and the least of 39 kN/m2 from briquette with 50꞉50 ratio of corncob to rice husk, 1.75 mm particle size and 25 kPa pressure. The briquette made from 50꞉50 ratio of corncob to rice husk, 0.25 mm particle size and 65 kPa pressure had the highest water resistance capacity, and the least from briquette of 80꞉20 ratio of corncob to rice husk, 1.75 mm particle size and 25 kPa pressure. The resulting physico-mechanical qualities of the produced corncob and rice husk briquettes suggested that they could be used as the solid fuels for domestic and industrial applications.

Experimental investigations on combustion characteristics of fuel briquettes made from vegetable market waste and saw dust

The safe and sound disposal of vegetable market waste (VMW) is a major concern of India today. VMW is being produced in millions of tonnes in urban areas, which are often deposited in dumpsites, left untreated, or burned in open fires. A potential remedy for these waste disposal and high fuel dependence on wood as fuel is the conversion of this biomass into high-density briquettes. This paper presents an experimental exploration of fuel properties of bio-briquettes made from a combination of VMW and sawdust (SD). In the present work, binary briquettes have been made from VMW in combination with SD in a ratio of 25, 50, 75, and 100% by weight using bentonite clay as a binder. Furthermore, a comparative study between the VMW basedbiomass briquettes with firewood, coal, and conventional sawdust briquettes are also included in this study. Raw green vegetable wastes were collected from markets and were kept for open sun drying. The dried matter was then transformed into a pulverized form and eventually converted to briquettes. The percentage of moisture content, percentage volatile matter content, ash content percentage, fixed carbon content, and calorific values of the briquettes were investigated. The results showed that the composite briquettes had improved combustion characteristics like higher calorific value and more volatile matter content compared with pure VMW briquettes. The percentage volatile matter content of VMW briquette enhanced from 71.72% to 83.2% for the composite briquette of VMW and SD with the highest percentage at the proportion 25:75 (VMW: SD). The calorific value of bio-briquettes ranges from 14.002 to 15.721 MJ/kg and the highest heating value was obtained for the composite briquette of VMW and SD with proportion 25:75. Even though lignin contents of vegetable market waste were lesser (3.23–5.51%) compared to other ligno-cellulosic biomass, good quality biomass briquettes were produced.

Experimental and Numerical Investigation of Reaction Behavior of Carbon Composite Briquette in Blast Furnace

The application of carbon composite briquette (CCB) is considered to be an efficient method for achieving low-energy and low-CO2-emission blast furnace (BF) operations. In this research, a combined experimental and numerical study was conducted on the CCB reaction behavior in BF. The CCB used in this study had a composition of 20.10 wt.% carbon, 29.70 wt.% magnetite, 39.70 wt.% wüstite, and 1.57 wt.% metallic iron. Using the prepared CCB samples, isotherm reduction tests under a simulated BF atmosphere (CO-CO2-N2) were conducted and a reaction model was developed. Subsequently, the reaction behavior of CCB along the mid-radial solid descending path in an actual BF of 2500 m3 was analyzed by numerical simulations based on the experimental findings and the previous results of comprehensive BF modeling. The results of the experiments showed that the CCB model predictions agreed well with the experimental measurements. With respect to the BF, the results of the numerical simulations indicated that, along the path, before the CCB temperature reached 1000 K, the CCB was reduced by CO in the BF gas; when its temperature was in the range from 1000 to 1130 K, it underwent self-reduction and contributed both CO and CO2 to the BF gas; when its temperature was above 1130 K, it only presented carbon gasification. Moreover, these results also revealed that the reduction of iron oxide and the gasification of carbon inside the CCB proceeded under an uneven mode. The uneven radial distribution of the local reduction fraction and local carbon conversion were evident in the self-reducing stage of the CCB.

Microwave-assisted self-reduction of EAF dust-biochar composite briquettes for production of direct reduced iron

This study applied microwave energy for rapid self-reduction of electric arc furnace (EAF) dust-biochar composite briquettes to produce powdered direct reduced iron (DRI), based on the good electromagnetic response of EAF dust-biochar composite briquettes. The reduction experimental results showed that the iron-bearing components in the dust were reduced to metallic iron, leading to a high iron metallization degree of the reduced briquettes (94.7%). Meanwhile, the zinc-containing phases of EAF dust in the composite briquettes were converted to metallic zinc which then volatilized together with lead in the form of PbCl2. The volatilization percentages of zinc and lead were 99.6% and 92.9%, respectively, after reduction with the mass ratio of biochar to EAF dust of 0.25 and heating rate of 25 °C/min at 1050 °C for 15 min. By magnetic separation of the reduced briquettes, a magnetic concentrate with iron content of 91.32 wt% and recovery of 87.36% was obtained, meeting the quality requirements of DRI.

Justification of the method for phytoremediation of degraded and contaminated lands by composite vermicompost briquettes

The object of research is the effectiveness of the use of vermicompost products of vermicultivation in the practice of phytoremediation of degraded and technogenic contaminated lands. One of the problematic aspects in solving the scientific problem of reclamation of lands degraded as a result of technogenic activity is the long-term stage of biological restoration of the disturbed landscape. For a more efficient and quick reclamation, it is advisable to create a phytocenosis from tree-shrub vegetation, resistant to negative environmental influences. Well-tested biotechnologies of vermicultivation create the prerequisites for the use of waste products of the colonies of the worms of the genus Eisenia in the form of composite vermicompost briquettes for the needs of land phytoremediation, and it is proved in the study.The analysis of literary sources using modern technologies of vermicultivation and the use of vermicompost products for the needs of agriculture and land phytoremediation is carried out. The growth process of the biomass of worms of the Eisenia fetida species and the accumulation of vermicompost over time depending on the temperature of the medium are studied. The results of laboratory bioindication experiments with composite briquettes, consisting of vermicompost, loam and seeds of wild cereals, are presented. It is determined that the ratio of vermicompost and loam in the composition of composite briquettes, which is the most optimal for plant growth indicators, is 60:40 and 40:60 by mass, which makes it possible to justify the phytomeliorant working mixtures for biological land reclamation technologies.Laboratory studies have shown the promise of using vermicompost as a product of vermicultivation in the form of composite briquettes in the practice of phytoremediation of disturbed lands.

Optimization of Binder for Improving Strength and Shatter Index of Briquettes for BOF Dust using Design of Experiments

Effectiveness of Recycling of steel plant waste is very much dependent on agglomeration technique. Sintering, pelletization and briquetting are some of the techniques which are frequently used for waste utilization. Aim of this study is to prepare composite briquettes by cold bonding technique, by which phsico-chemical changesoccurred at room temperature or low temperature. Two binders are mixed in proportion to achieve the required properties specifically strength and shatter index. The design of experiments is used to find the proper combination of binders to get the optimum value of properties. Experimental work for the same is carried out in such a way that minimum number of experiment can give output as desired. For this ‘Design of Experiment’ methodology is applied to select the runs of experiment. After the selection of orthogonal array and experiment combinations, Taguchi technique is used with two variable (starch and molasses) and three levels (2.5%, 5% and 7.5% of each) i.e. L9 Array to analyze the results. Minitab15 software is used. Conclusion and comments are based on the same.