Preparation Of Briquettes Research Articles

Effect of mixing-ratio and current on Mo-Cu-WC-Si coating via EDC

The present study investigates the influence of the mixing ratio of copper (Cu) and molybdenum (Mo) powders in Mo-Cu-WC-Si composite powder metallurgy (P/M) briquettes on the performance of coatings produced on Al-2014 alloy using electrical discharge coating. Three mixing ratios of Cu and Mo are selected during briquette preparation, by varying Cu in 5 wt.% decrements and Mo in 5 wt.% increments: 50Cu:30Mo, 45Cu:35Mo, and 40Cu:40Mo, with fixed 15WC:5Si. The results indicate that even a 5 wt.% variation of copper significantly affects the coating output responses. At 3 A current the 50Cu:30Mo combination shows lowest roughness of 2.4 μm, followed by 3.2 μm, and 5.4 μm roughness with 45Cu:35Mo and 40Cu:40Mo. Coating with 50Cu:30Mo ratio shows the highest wear reduction, achieving a 3-fold decrease compared to the uncoated Al-2014. Furthermore, coated samples depict a 42% reduction in corrosion rate compared to uncoated sample. Experimental results suggest that the briquette with a higher copper percentage (50 wt.%) provides a more suitable coating.

Physicochemical characterization of briquette fuel produced from cocoa pod husk case of Cameroon

This paper aims to prepare and evaluate the physicochemical and energetic properties of briquette fuel made from cocoa pod husk. For briquette preparation, cocoa pod husk was dried, carbonised, crushed, mixed using binder, compacted, and finally the briquettes obtained were dried. The briquettes produced were characterised by proximate analysis, ultimate analysis, infrared spectroscopy, and thermogravimetric analysis using the American Society for Testing and Materials (ASTM) and the European Committee for Standardisation (CEN) standards. The results from the proximal analysis obtained (10.5%), (6.5%), (34.7%), and (58.8%), respectively, for moisture content, ash content, volatile matter, and fixed carbon, are satisfactory values. The results from the ultimate analysis found are 53.2%, 5.2%, and 34.4%, respectively, for carbon, hydrogen, and oxygen content, while H/C and O/C gave 1.17 and 0.48, respectively. The Higher Heating Value (17.941 MJ/kg) proved high thermal stability, with the highest mass loss of 32.50% at 361°C due to the high extractive content and the aromatic structure of the polymer. The presence of C-O, CC, CHx, and OH groups was noticed, while the fuel value index (FVI) and impact resistance index (IRI) showed 1104% and 125%, respectively. These results indicated that the abundance of these residues in landfills could serve as an alternative fuel energy source with environmental friendly features and contribute to the economic growth of the country.

Enhancement of strength of blast furnace flue dust – iron oxide – fly ash composite briquette using ANOVA-based mathematical model

ABSTRACT Utilisation of by-products of an integrated steel plant improves productivity with diverse mix of raw materials used for iron making. The strength of a briquette made with Blast furnace flue dust and iron oxide with fly ash as a binder depends upon the briquetting pressure, particle size of fly ash, fly ash quantity, and curing temperature. In this study, the effect of process variables on the strength was investigated with ANOVA. The correlation between the process parameters and the strength was examined experimentally and RSM-based optimisation was performed during the preparation of briquettes. The RSM provided optimisation with a confidence level of 95% using the CCD design. This paper demonstrates the correlation between applied pressure, particle size, fly ash quantity, and curing temperature. The developed mathematical model would help in predicting the variation in the compressive strength with the change in the level of different parameters. This model can be useful for setting the optimum value of the parameters for achieving the target compressive strength.

Emission characteristics and cytotoxic effects of PM2.5 from residential semi-coke briquette combustion

Coal combustion emits large amounts of PM2.5 (particulate matter with a diameter of ≤ 2.5 μm), and the emissions from different coal types differ. Clean fuels are essential in reducing PM2.5 emissions and their respiratory effects on human. This study compared PM2.5 emissions and their chemical components from four types of coal (i.e., bituminous raw-coal chunk, semi-coke briquette, anthracite, and bituminous briquette). The bioreactivies triggered by PM2.5 exposure to human alveolar epithelial (A549) cells were compared, and the emission factors (EFs) of bioreactivies were calculated. The PM2.5 EFs of semi-coke briquettes were reduced efficiently compared with those of raw-coal chunk, and their chemical profiles also differed. The contribution of total carbon and metals (i.e., S, Cl, Zn, and Pb) was higher for semi-coke briquette relative to raw-coal chunk, which may be due to the concentration effect of the semi-coke briquette preparation process. The production of lactate dehydrogenase (LDH) and reactive oxygen species (ROS) was higher for semi-coke briquette relative to raw-coal chunk at the PM2.5 exposure dose of 100 μg mL−1. The EFs of LDH and ROS for semi-coke briquette, anthracite, and bituminous briquette were substantially lower than those for raw-coal chunk, which verified the effects of clean coal on oxidative stress and cytotoxicity. Organic carbon and specific heavy metals (i.e., Cu, Fe, Ni, Zn, Pb, and Cr) were significantly correlated with cell membrane damage and oxidative stress. This study clarifies potential adverse effects of PM2.5 emissions from the combustion of various coal types and highlights the necessity of adopting clean coal to reduce PM2.5 emissions and cytotoxicity.

Evaluation of composite briquettes from dry leaves in energy applications for agrarian communities in India

The current study was carried out to explore the characteristics of biomass briquettes produced with different proportion of dry leaves, sawdust, and rice husk with starch as binder. The briquettes were created in the laboratory with a compression testing machine at a pressure of 150 MPa. The biomass particles, which are smaller than 1.18 mm, were utilized. The heating value and the ultimate analysis were determined by means of an empirical formula based on the values obtained from the proximate analysis. After a drying period of 7 days, the quality of the briquettes was evaluated. Briquette made from 100% dry leaves showed the highest density (1.193 g/cc) heating value (4789 kcal/kg), shatter resistance (89%), and water resistance (68.56%) and fixed carbon (25.58%). The heating value and durability performance have validated the use of dry leaves for the preparation of briquettes. The study demonstrates a way to reduce dry leaves waste, which could be utilized as a biomass fuel.

Preparation of Briquettes on the Basis of Sub-Standard Coal of Kazakhstan Fields

A technology of briquetting of sub-standard coal of Kazakhstan fields to obtain high-quality briquetting fuel has been developed. A modifying additive in the form of oil residues has been selected, that make it possible to obtain a binder composition for brown coal briquetting. The material for the preparation of coal briquettes is coal fines from dry, poorly sintered coals, which cannot be used for direct combustion in the furnace. The optimal parameters for obtaining high-quality fuel briquettes have been determined. The introduction of a modifying additive into the oil residues makes it possible to obtain a binder composition for briquetting brown coal. Studies of the physical parameters of briquettes and the data of SEM showed that the thickness of the adsorption layer of coal and the cohesion of the binder in thin layers play an important role in the formation of the structure and strength of the briquette. It was assumed that at the optimum thickness of the film layer, the maximum manifestation of capillary forces and an increase in the adhesive interaction between the particles and the binder take place. The organic component of the coal fines is a mixture of various X-ray amorphous components, the presence and number of which vary in a series of metamorphism. The results of the performed studies show the possibility and prospects of using local raw materials for the development of high-quality briquetted brown coal fuel.

Effect of molecular carbon structures on the evolution of the pores and strength of lignite briquette coal with different heating rates

Briquette coal (BC) is the material produced from coal and gas outburst experiments. Preparing BC via the heating and pressure method can improve its low mechanical strength in physical simulation tests and gas outbursts while increasing experimental reliability. However, the influence of heating rate on the mechanical properties and microstructure of BC and the reasons underlying the evolution of its mechanical strength analyzed in terms of carbon molecular structure still need to be further studied. In this study, we developed an experimental system to prepare BC. The influence of the pore and carbon molecular structure on the BC uniaxial compressive strength was examined via a rock mechanics test system, scanning electron microscopy, nuclear magnetic resonance, specific surface area analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. The results indicated that when the heating rate was increased from 3 to 6 °C/min, the briquette structure changed from looser smooth sheets to rough agglomerates of coal. The pore types observed after four different heating treatments (3, 4, 5, and 6 °C/min) on briquette samples were primarily micropores and mesopores. At 5 ℃/min, the number of micropores in the briquette sample were significantly higher than that observed in other samples. All samples exhibited similar adsorption curves as those of inverted “S”-type coal samples, which can be regarded as a combination of Type IV isotherms. With increasing heating rates, the La and Lc first increased and then decreased, with a decrease in Aar/Aal, whereas Hal/H and CH2/CH3 increased. The strength of coal samples under the increasing heating rates were 5.62, 6.43, 7.07, and 5.99 MPa, respectively. The heating rate of 5 ℃/min was found to be the appropriate heating rate for briquette preparation. These results can provide an excellent alternative raw material required for large-scale physical simulation experiments for the prevention and control of coal and gas outbursts.

Experimental Study on the Influence of Moisture Content on the Mechanical Properties of Coal

Water injection in coal seams will lead to the increase of moisture content in coal, which plays an essential role in the physical and mechanical properties of coal. In order to study the influence of moisture content on the mechanical properties of soft media, the forming pressure (20 MPa) and particle size ratio (0-1 mm (50%), 1-2 mm (25%), and 2-3 mm (25%)) during briquette preparation were firstly determined in this paper. Briquettes with different moisture contents (3%, 6%, 9%, 12%, and 15%) were prepared by using self-developed briquettes. Uniaxial and triaxial compression tests were carried out using the RMT-150C rock mechanics test system. The results show that the uniaxial compressive strength and elastic modulus of briquette samples increase first and then decrease with the increase of briquette water, while Poisson’s ratio decreases first and then increases with the increase of briquette water. When the moisture content is around 9%, the maximum uniaxial compressive strength is 0.866 MPa, the maximum elastic modulus is 1.385 GPa, and Poisson’s ratio is at the minimum of 0.259. The compressive strength of briquettes increases with the increase of confining pressure. With the increase of moisture content, the cohesion and internal friction angle of briquettes first increased and then decreased.

RENEWABLE ENERGY OF BIOMASS BRIQUETS AND ORGANIC BINDERS

In places where energy is scarce or not available enough for the development of many activities, the use of briquettes based on animal or plant biomass can very well help to meet that need. The residues of the coffee, cocoa and wheat production called husks and at the same time agglutinated with residues of potato and molasses, were used for the preparation of briquettes that presented good calorific value with an average of 9909.59 Kcal / Kg (cocoa), 9912.81 Kcal / Kg (coffee) and 9928.11 Kcal / Kg wheat), respectively.

High strength clean briquettes production from long‐flame coal fines by using polyvinyl alcohol and coal slime as binders

AbstractHigh strength clean briquettes production by using recycling coal fines is of great realistic significance in saving coal resources and protecting the environment. Blends consisting of a long‐flame coal fines and coal slime (CS) and polyvinyl alcohol (PVA) as binders were used in the preparation of briquettes. To produce a qualified clean briquette with enough briquette strength, the effects of the binder content, briquetting pressure, and moisture content were systemically investigated. The results indicated that the briquettes prepared by using blended binder with 20 wt.% of CS and 1 wt.% of PVA showed better compressive strength (10.2 MPa) and drop strength (98.3%). CS with particle size less than 0.2 mm could fill in the gap between the coarse coal particles uniformly, thus reinforcing the embedded state and leading to a higher briquette strength. Moreover, the strength of the briquettes was also affected by the briquetting pressure and moisture content. At briquetting pressure of 60 kN and optimum moisture content of 14%, the highest briquette strength was achieved. The hydroxyl content of the briquettes by adding CS and PVA increased significantly. In this condition, a highly viscous network colloid was formed when the PVA and water were mixed together. When the briquettes were dried, the colloid could produce a dendritic structure, which was mechanically embedded between adjacent coal particles.

Briquette preparation with biomass binder

ABSTRACT Residential coal combustion is regarded as a major contributor to severe haze pollution in China, and clean briquettes are supported as a way of reducing emissions. In this study, Shendong coal (SC) and a composite binder made from maize straw (MS) were used to prepare a briquette with higher combustion characteristics and lower pollution emissions by using a newly designed method. Thermochemistry and emission characteristics of samples were studied by using a thermogravimetric analyzer and a tube combustion experimental system, respectively. The results showed that for a 20% biomass mass fraction with <0.5 mm particle size, biomass treatment with alkali agents or the addition of a sulfur-fixing agent resulted in significantly reduced SO2 emission; however, molding the sample increased total SO2 emissions, particularly in the early stages. NO emission decreased markedly with biomass, alkali-treatment or the addition of a sulfur-fixing agent. However, NO emission increased when the biomass had a particle size of 0.5–2 mm and when the sample was molded.

Recovered polyvinyl alcohol as an alternative binder for the production of metallurgical quality coke breeze briquettes

ABSTRACT Coke breeze briquettes are promising low-cost substitute to metallurgical coke, prepared by adding binder to the coke breeze to form briquettes. At present, pregelatinized starch is used as binder in the preparation of briquettes, but its food and confectionary applications restrict its usage on account of high cost and ease of availability. Subsequently, there is a necessity to develop alternative binders for the briquetting process, without affecting the briquette properties. Polyvinyl alcohol (PVA) could be one such possible binder. The textile industry generates waste streams with significant amounts of PVA that can be recovered by membrane filtration. The present work, therefore investigates the possibility of using pure polyvinyl alcohol (pPVA), recovered polyvinyl alcohol (rPVA), and mixtures of rPVA with pregelatinized starch as binders for coke breeze briquetting. Weak green briquettes were produced by rPVA binder. The quality of briquettes improved after addition of pregelatinized starch to rPVA and this was found to be equivalent to pure polyvinyl alcohol (pPVA) binder briquettes. The mixed (rPVA+ Pregelatinized starch) binder produced briquettes with UC strength 1347 kPa. The study demonstrates the fact that good quality briquettes can be formed by rPVA when used in combination with minimal quantities of pregelatinized starch.

Investigation into the Interaction of Exogenous Refractory Nanophases with a Fe–C–Si Melt (Cast Iron) at 1350°С: I. Justification of the Selection of Nanophases and the Study of Heterophase Interaction

Per the literature, the thermodynamic stability criterion of the dispersed system of nanosized phases in metal melts is reproduced, with the latter considered the specific change in free energy (referred to the unit of change in the contact surface of the phases) of the disperse system aggregation. For iron–carbon melts with [C] > 2 wt %, according to the published scientific results, the selection of two refractory phases SiC and TiC0.8N0.16O0.04 for introduction into the Fe–C–Si–Mn–P–S–O melt is justified. The preparation of nanophases, the preparation of briquettes of a composite material, and the method used to study the interfacial interaction of nanophases with sulfur and oxygen of the melt is described. It is shown that a decrease in the surfactant content of the nanophase content upon 5–10 min of exposure indicates the interaction of the surfactant with nanoparticles, and the concentration dependences are characterized by extreme minimum values.

Investigation on the physical properties of the charcoal briquettes prepared from wood sawdust and cotton stalk

ABSTRACT The physical properties of the charcoal briquettes prepared from biomass waste are usually poor. In the paper, an alternative approach to the charcoal briquette preparation from the densified biomass briquette by carbonization was addressed. The carbonization process of the biomass briquettes prepared from cotton stalk (CS), wood sawdust (WS) and their blends was performed in a fixed bed at 400~600°C. The variation in the mass and volume of the biomass briquettes before and after the carbonization process and the physical properties of the resulted charcoal briquettes were investigated. The results indicate that the physical properties of the charcoal briquettes including bulk density and compression strength decreased firstly and then increased as the temperature increased. CS charcoal briquettes with better physical properties showed more volume shrinkage than WS charcoal briquettes after the carbonization process. However, the physical properties of the charcoal briquettes from the blends were poorer than expected due to the co-pyrolysis characteristics of CS and WS.

Importance of Biomass and Binder Selection for Coking Briquette Preparation. Their Effect on Coal Thermoplastic Properties

Blends consisting of a high volatile bituminous coal, biomass, and binder that were used in the preparation of briquettes were analyzed in order to select the best components from the viewpoint of ...

Effects of binder choice in converter and blast furnace sludge briquette preparation: Environmental and practical implications

Blast furnace and converter sludges are fine-grained waste materials characterized as dangerous waste with a negative impact on the environment. One way of recycling of such materials is briquetting followed by reuse of the material in the blast furnace. In the briquetting process, an important step is the choice of the binder suitable for manufacturing the briquettes with suitable mechanical properties. In this work, the effect of the binder choice (laundry starch UNIPRET, Portland cement) on the reduction of iron oxides in the assessed waste materials during thermal treatment (900, 1000, 1100 °C) is evaluated. Simultaneously, the effect of the binder choice on the amount and composition of the resulting waste gas was evaluated as well as its possible impact on the environment. The performed experiments proved the mutual relationship between the level of iron oxides to metal iron conversion, the binder content and retention temperature. Type of binder also affected the volume of the resulting waste gas. Factor analysis for mixed data (FAMD) proved that the resulting concentrations of the assessed hydrocarbons were correlated (apart from ethyne) and that they are closely associated with the binder applied. Conversely, the concentrations of ethyne, carbon monoxide and carbon dioxide were not associated with the binder but with the retention temperature. FAMD did not show any direct effect of final retention temperature on the amount of the rest of the resulting hydrocarbons. In comparison with the starch-containing briquettes, the cement-containing briquettes were also proved to lead to lower resulting concentrations of PAHs in the waste gas.

Preparation and Properties of Pulp Black Liquor Briquettes

Effects of adding pulping black liquor in the preparation of briquettes were evaluated relative to the properties of the resulting pulp black liquor briquettes. The addition of 2% binder (pregelatinized starch) and a molding pressure of 5 MPa were sufficient to obtain briquettes that complied with DB13/1055 (2009). When 30% of pulping black liquor was added in the preparation of briquettes, the compressive strength, shatter index, moisture content, and the content of volatile matter and ash of the resulting briquettes increased. Moreover, the combustion performance of the briquettes after the addition of black liquor was higher, where the briquettes exhibited an enhanced ignition point, a more stable combustion process, and a 50% higher sulfur-fixation ratio after combustion, compared to the ordinary briquette. However, the thermal stability and calorific value decreased and the ash after combustion of the black liquor briquette contained a higher content of high melting point salts. Therefore, the addition of pulping black liquor in the composition of briquettes should be moderate. The preparation of black liquor briquettes provides an efficient way for utilization of black liquor.

Influence of binder type on greenhouse gases and PAHs from the pyrolysis of biomass briquettes

Five blends prepared with torrified sawdust, coal plus either coal tar, coal tar sludge, paraffin or molasses designed to serve as binder in the preparation of briquettes were pyrolysed in a rotary oven. The coal and the torrified sawdust used in the preparation of the blends were also studied. The condensable gases were analyzed by gas chromatography (GC) and infrared spectroscopy (FTIR). The permanent gases were also analyzed by gas chromatography. The concentration of nineteen polyaromatic hydrocarbons in the condensable products was analyzed with special focus on those considered as priority and carcinogenic pollutants. The results obtained from FTIR were confirmed by those obtained by GC. It was found that the inclusion of biomass produces a decrease in the amount of (polyaromatic hydrocarbons) PAHs in the condensable pyrolysis products and an increase in the concentration of CO2 in the gases, although these gases are carbon neutral.

High-strength charcoal briquette preparation from hydrothermal pretreated biomass wastes

The waste cotton stalk (CS) and wood sawdust (WS) biomass samples pretreated by two different thermal methods (dry torrefaction (DT) and hydrothermal treatment (HT) at 200, 230, 260°C, respectively) were densified to prepare biomass briquette and then carbonized at 400°C to prepare charcoal briquette without any binders. The physical properties and combustion characteristics of the derived charcoal briquettes were investigated to assess the feasibility of its application as barbecue charcoal. The results indicate that the physical properties including the mass densities and compressive strengths of HT charcoal briquettes are better than those of DT and unpretreated charcoal briquettes, even those of the commercial barbecue charcoal with binder addition. Moreover, the fixed carbon and ash yields of the resulted HT charcoal briquettes meet the European Standard on commercial barbecue charcoal. Especially HT charcoal briquettes has far lower ash yield than the commercial barbecue charcoal. HT charcoal briquettes have similar combustion character index (S) with the commercial barbecue charcoal. In the research, CS and WS hydrothermal pretreated at 230°C are the best materials for the charcoal briquette preparation process.

Design of structure and simulation of the three-zone gasifier of dense layer of the inverted process

Experts of LLC “New Energy Technologies” have developed gasifiers designs, with the implementation of the three-zone gasification method, which satisfy the following conditions: 1) the generated gas must be free from tar, soot and hydrocarbons, with a given ratio of CO/H2; 2) to use as the fuel source a wide range of low-grade low-value solid fuels, including biomass and various kinds of carbonaceous wastes; 3) have high reliability in operation, do not require qualified operating personnel, be relatively inexpensive to produce and use steam-air blowing instead of expensive steam-oxygen one; 4) the line of standard sizes should be sufficiently wide (with a single unit capacity of fuel from 1 to 50-70 MW). Two models of gas generators of the inverted gasification process with three combustion zones operating under pressure have been adopted for design: 1) gas generator with a remote combustion chamber type GOP-VKS (two-block version) and 2) a gas generator with a common combustion chamber of the GOP-OK type (single-block version), which is an almost ideal model for increasing the unit capacity.There have been worked out various schemes for the preparation of briquettes from practically the entire spectrum of low-grade fuel: high-ash and high-moisture coals, peat and biomass, including all types of waste - solid household waste, crop, livestock, poultry, etc. In the gas generators there are gasified the cylindrical briquettes with a diameter of 20-25 mm and a length of 25-35 mm.There have been developed a mathematical model and computer code for numerical simulation of synthesis gas generation processes in a gasifier of a dense layer of inverted process during a steam-air blast, including: continuity equations for the 8 gas phase components and for the solid phase; the equation of the heat balance for the entire heterogeneous system; the Darcy law equation (for porous media); equation of state for 8 components of the gas phase; equations for the rates of 3 gas-phase and 4 heterogeneous reactions; macro kinetics law of coke combustion; other equations and boundary conditions.