Coal Briquettes Research Articles

Migration of inert materials during coking of molded coal

Since the maldistribution of substances with poor melting and expansion properties decreases the strength of coke, we investigated whether these substances gather or disperse during coking process. Coal briquettes (before coking) and cokes (after coking) containing a predetermined amount of alumina beads were prepared. These beads constituted 2–15 vol% of the samples. A three-dimensional analytical object was constructed by X-ray CT images of coal briquette or coke with alumina beads, and isolated alumina beads were extracted from analytical objects by image processing. The number of isolated alumina beads increased after coking in any mixing ratios. Therefore, it was shown that the alumina beads dispersed each other during coking. The observed result could be attributed to the expansion of pores near the contact points between agglomerated alumina beads, resulting in the expulsion of the beads. At the lower part of the sample, where the effect of expansion was small, the same ash before and after carbonization can be found. Focusing on the area near the ash, alumina beads with the same distance from the same ash are observed before and after the coking. This indicates that there are alumina beads that have not moved during coking. The reason why the alumina beads did not move may be using low fluidity coal and high-density coal briquette as the raw material of coke. This suggests that the high-density coal briquette may prevent the coke strength from decreasing due to the suppression of insoluble matter agglomeration.

Analisis Penambahan Larutan Gula Terhadap Kuat Tekan dan Kuat Lentur Beton yang Mengandung Arang Briket

Concrete is frequently used as the primary component of building construction. Given its role as a former, concrete plays a significant role in the construction industry. To make pozzolanic concrete more useful as a mineral ingredient for concrete, coal briquette charcoal ash, and sugar solution are added to the mixture. The aim of this study was to determine the impact on concrete's compressive strength and flexural strength by adding 0.10%, 0.20%, and 0.30% sugar solution containing 5% charcoal briquettes. There were 39 specimen samples, including 16 samples of variance concrete and 23 samples of regular concrete. Concrete on the test object is treated by immersing it for 28 days. When the specimen was 28 days old, the concrete's compressive and flexural strengths were evaluated. According to the test's findings, variation concrete has greater compressive and flexural strengths than regular concrete. The compressive strength and flexural strength of the concrete mixture increase with the amount of sugar solution added

Influences of double-sided molding method and initial particle size on fragmentation characteristics of reconstituted coal briquette

Using the reconstituted coal briquette to replace tectonic coal is a forced choice for many experimental studies on the mechanism of coal and gas outbursts. The molding method and initial particle size are two important factors affecting the properties of the soil-like coal briquette. In this study, tectonic coal particles with five different initial sizes were compressed into coal briquettes using three different molding methods. Each coal briquette was evenly divided into five parts along the vertical direction and each subunit was fragmented by a drop hammer to test the firmness. The results show that the briquette density first increases and then decreases with the rise of initial particle size. Briquettes obtained by the traditional one-sided molding method possess the lowest density. The fragment size distributions of the briquettes and the original tectonic coal have segmented and non-segmented fractal characteristics, respectively, which are mainly related to the initial particle size distribution of the coal powder used for making briquettes. Combining the vertical distribution laws of the surface work, Protodyakonov coefficients, and fractal dimension of the briquettes, it is determined that the coal briquettes obtained by the double-sided molding method are soft in the middle and possess a relatively symmetric structure. The surface work and Protodyakonov coefficients of the briquettes (9.03 ± 2.27 J/m2 and 0.10 ± 0.02, respectively) are comparable to those of the in-situ tectonic coal with the highest outburst risk.

ANALISIS PROKSIMAT PADA BRIKET BATUBARA NON KARBONISASI TERHADAP JENIS DAN KOMPOSISI PEREKAT TAPIOKA DAN PEREKAT SAGU

The demand of the fuel oil in the world increasing with the rate population and industrial growth. The alternative solid fuel which is the main ingredient of that is coal, contains the high calorific value so that it can be replaced petroleum product and be used is briquette. In this study conducted proximate test on non-carbonized coal briquettes beetwen tapioca adhesive and Sago adhesive. In the study, the methods used approach issues of extracting research from established theories and data of observed objects. The analysis result of proximate test briquettes coal with tapioca adhesive on Balikpapan Formation, pulau balang Formation, kampung baru formation obtained the value of IM is 11,68% - 24,48 %, AC is 2,62 - 5,68 %, VM is 39,40 - 52,49 %, and FC is 12,95 - 46,32 %. whereas on coal briquettes with Sago adhesive on Balikpapan Formation, pulau balang Formation, kampung baru formation obtained the value IM is 13,11 - 30,57 % on, AC is 3,71 - 5,75 %, VM is 47,83 - 53,22 %, and FC is 10,47 - 41,34 %.

Emission Characteristics of Organic Carbon and Elemental Carbon in PM10 and PM2.5 from Vehicle Exhaust and Civil Combustion Fuels

To study the emission characteristics of carbonaceous aerosol in particulate matter emitted from vehicle exhaust and main civil combustion fuels, organic carbon (OC) and elemental carbon (EC) in PM10 and PM2.5 samples from vehicle sources (gasoline vehicles, light duty diesel vehicles, and heavy duty diesel vehicles), civil coal (chunk coal and briquette coal), and biomass fuels (wheat straw, wood plank, and grape branches) were collected and analyzed by using a multifunctional portable dilution channel sampler and the Model 5L-NDIR OC/EC analyzer. The results showed that there were significant differences in the proportion of carbonaceous aerosols in PM10 and PM2.5from different emission sources. The proportions of total carbon (TC) in PM10 and PM2.5 of different emission sources were 40.8%-68.5% and 30.5%-70.9%, respectively, and the OC/EC were 1.49-31.56 and 1.90-87.57, respectively. The carbon components produced by different emission sources were dominated by OC, and the OC/TC values in PM10 and PM2.5 were 56.3%-97.0% and 65.0%-98.7%, respectively. The proportions of OC in carbonaceous aerosols in PM10and PM2.5 were in the descending order of:briquette coal>chunk coal>gasoline vehicle>wood plank>wheat straw>light duty diesel vehicle>heavy duty diesel vehicle and briquette coal>gasoline car>grape branches>chunk coal>light duty diesel vehicle>heavy duty diesel vehicle, respectively. The main components of carbonaceous aerosols in PM10 and PM2.5 emitted from the various emission sources were different, and source apportionment of carbonaceous aerosols could be accurately distinguished by their ingredient composition profiles.

Analysis of Different Types of Carbonaceous Reductants and Methods of Slag and Sludge Recovery at Converter Production

Recycling of metal-containing wastes with an iron content of more than 15%, such as slag and sludge from the gas cleaning of converter production, can be used to recover the metal. In order to study the reducing properties of coal sludge, coke breeze (coke), Shubarkol coal, a series of experimental melting of coal sludge briquettes with different contents of the listed carbon-containing materials was carried out. Sludge-coal briquettes were made from converter slag and sludge using hydrated lime as a binder. To determine the necessary parameters for the reduction of the iron-containing element, chemical and technical analyzes were carried out for ash content, moisture content and volatile matter. The choice of the optimal component composition of briquetted mixtures has established that the proportion of the reducing agent in the briquette should not exceed 20...25%, in order to avoid excess carbon, which binds into solid carbide compounds. The share of the reducing agent in the briquette was 15...18%. Chemical analysis of the resulting alloy and slag component pointed out the expediency of using Shubarkol coal as a carbonaceous reducing agent with high reactivity and electrical resistivity

Brown Coal and Logwood Combustion in a Modern Heating Appliance: The Impact of Combustion Quality and Fuel on Organic Aerosol Composition.

Residential heating with solid fuels is one of the major drivers for poor air quality in Central and Eastern Europe, and coal is still one of the major fuels in countries, such as Poland, the Czech Republic, and Hungary. In this work, emissions from a single-room heater fueled with brown coal briquettes (BCBs) and spruce logs (SLs) were analyzed for signatures of inorganic as well as semivolatile aromatic and low-volatile organic constituents. High variations in organic carbon (OC) emissions of BCB emissions, ranging from 5 to 22 mg MJ-1, were associated to variations in carbon monoxide (CO) emissions, ranging from 900 to 1900 mg MJ-1. Residential BCB combustion turned out to be an equally important source of levoglucosan, an established biomass burning marker, as spruce logwood combustion, but showed distinct higher ratios to manosan and galactosan. Signatures of polycyclic aromatic hydrocarbons emitted by BCB combustion exhibited defunctionalization and desubstitution with increasing combustion quality. Lastly, the concept of island and archipelago structural motifs adapted from petroleomics is used to describe the fraction low-volatile organic compounds in particulate emissions, where a transition from archipelago to island motifs in relation with decreasing CO emissions was observed in BCB emissions, while emissions from SL combustion exhibited the island motif.

Stress Sensitivity Analysis of Seepage Pores in Coal Briquettes Based on Compressed Exhaust and Pressure-Transient Tests

Seepage pores are the main space for methane transport in the coal seam. To further investigate variation laws of seepage pores with stress, this study established a new method based on the compressed exhaust and pressure-transient tests to characterize the seepage pore size distribution under different effective stress conditions. The reconstituted coal briquette and nonabsorbent helium were adopted as the experimental samples. The results showed that the deformation of coal mass mainly originates from seepage pores. With the increase of confining stress, the volume reduction of seepage pores presents a logarithmic growth. The initial seepage porosity of the tectonic coal specimen, i.e., the seepage porosity when effective stress is zero, was estimated to be 5.28%, accounting for 36.24% of the total porosity obtained by helium saturation. When effective stress is in the range of 13–48 MPa, the size of seepage pores generally ranges from 0.1 to 1.0 μm. The volume of seepage pores with sizes ranging from 0.1 to 0.5 μm always accounts for more than 80% of the volume of total seepage pores, and this proportion is not affected by effective stress. The inverse proportional coefficient between the threshold pressure gradient of helium and seepage pore diameter was finally determined to be 0.55 ± 0.19 mPa.

Optimization of decoupling combustion characteristics of coal briquettes and biomass pellets in household stoves

Burning coal briquettes or biomass pellets in household decoupling stoves is of significance to the reduction of residential pollutant emissions such as NO and CO. In order to make full use of the superiority of decoupling combustion technology, the household stoves should be specially designed and optimized to adapt to fuel types and combustion characteristics. Using numerical simulation and experimental validation, this study quantitatively clarified that the reducibility of devolatilization char plays an important role in the suppression of NO emission in the decoupling combustion of coal, while the reducibility of pyrolysis gases has a dominant effect on the reduction of NO in the decoupling combustion of biomass. An optimal parameter combination of throat height and grate angle was obtained for the simultaneous suppression of NO and CO emissions in the household decoupling stove burning coal briquettes. Two types of decoupling stoves were developed to enable the clean combustion of biomass pellets. The A-type biomass stove with a multi-pass smoke tunnel shows a better comprehensive NO and CO reduction effectiveness than the B-type biomass stove consisting of a two-stage grate structure and an S-shaped pyrolysis chamber. The optimal structural parameters provided references for the design and manufacture of commercial decoupling coal and biomass stoves.

Advantages and risks of using ore-coal briquettes in blast furnaces

Reducing carbon consumption, and, consequently, CO2 emissions during iron smelting in blast furnaces is a priority for improving the technology of blast furnace smelting. In the literature, the question of the influence of the development of direct reduction of iron on the consumption of carbon as a source of reducing gas and a source of heat has been considered. In this case, the development of direct reduction in the lower zone of the furnace at temperatures above 900 °C is considered. However, direct (solid-phase) reduction can be implemented in the upper zone of a blast furnace when using ore-coal briquettes in the charge. It is shown that the solid-phase reduction reactions can proceed at temperatures above 700 °C in the upper zone of a blast furnace during the reduction of Fe3O4 and FeO. At the same time, the apparent heat capacity of the charge increases and the temperature of the top gas decreases, which is confirmed by data on the operation of blast furnaces of NLMK PJSC, which use ore-coal briquettes. The raw materials for the production of briquettes are iron ore concentrate, sludge, blast furnace dust, aspiration dust. A bentonite and a ce-ment are used as a binder. The briquettes contain 40‒42% iron and 10‒15% carbon. The theoretical analysis and statistical processing of data on the operation of blast furnaces led to the conclusion that the solid-phase reduction of iron oxides actively proceeds at temperatures below 900 °C. The results of experimental heats showed the use of briquettes allows to reduce the specific consumption of coke and the total carbon consumption of fuel. The prospects for the use of the briquettes are associated with an increase in their mechanical properties. The use of ore coal briquettes obtained from a concentrate with an iron content of 65‒68% will reduce the rate of fuel carbon and CO2 emissions.

Gas Particle Partitioning of PAHs Emissions from Typical Solid Fuel Combustions as Well as Their Health Risk Assessment in Rural Guanzhong Plain, China.

Air pollutants from the incomplete combustion of rural solid fuels are seriously harmful to both air quality and human health. To quantify the health effects of different fuel-stove combinations, gas and particle partitioning of twenty-nine species of polycyclic aromatic hydrocarbons (PAHs) emitted from seven fuel-stove combinations were examined in this study, and the benzo (a) pyrene toxicity equivalent (BaPeq) and cancer risks were estimated accordingly. The results showed that the gas phase PAHs (accounting for 68-78% of the total PAHs) had higher emission factors (EFs) than particulate ones. For all combustion combinations, pPAHs accounted for the highest proportion (84.5% to 99.3%) in both the gas and particulate phases, followed by aPAHs (0.63-14.7%), while the proportions of nPAHs and oPAHs were much lower (2-4 orders of magnitude) than pPAHs. For BaPeq, particulate phase PAHs dominated the BaPeq rather than gas ones, which may be due to the greater abundance of 5-ring particle PAHs. Gas and particle pPAHs were both predominant in the BaPeq, with proportions of 95.2-98.6% for all combustion combinations. Cancer risk results showed a descending order of bituminous coal combustion (0.003-0.05), biomass burning (0.002-0.01), and clean briquette coal combustion (10-5-0.001), indicating that local residents caused a severe health threat by solid fuel combustion (the threshold: 10-4). The results also highlighted that clean briquette coal could reduce cancer risks by 1-2 orders of magnitude compared to bulk coal and biomass. For oPAH, BcdPQ (6H-benzo(c,d)pyrene-6-one) had the highest cancer risk, ranging from 4.83 × 10-5 to 2.45 × 10-4, which were even higher than the total of aPAHs and nPAHs. The dramatically high toxicity and cancer risk of PAHs from solid fuel combustion strengthened the necessity and urgency of clean heating innovation in Guanzhong Plain and in similar places.

Evolution of the strength characteristics of briquette and raw coal containing fluid

The mechanical properties of coal containing fluid are an important factor affecting the safe mining of soft coal seams. In particular, for class III–V coal, coal and gas outbursts and other dynamic phenomena are prone to occur due to the influences of gas pressure and groundwater, which seriously threaten the safety and lives of field workers. However, briquette samples are usually used in place of raw coal in laboratory tests conducted on class III–V coal samples. Whether the research conclusions for briquette and raw coal are consistent and whether briquette coal can replace raw coal in research on strength characteristics need to be further verified. In this paper, the evolution of the strength characteristics of fluid-bearing briquette coal and raw coal is studied. The strength characteristics, instability failure characteristics, and acoustic emission characteristics of raw coal and briquette coal under uniaxial and triaxial compression are analyzed in detail. In addition, the influence of the water content and pore pressure on the strength characteristics of class III–V raw coal and briquette coal is further studied. The results show that the failure characteristic of raw coal is overall brittle failure, mainly axial splitting failure, whereas that of briquette is overall ductile failure, mainly cone-shaped continuous spalling. The strength parameters of the raw coal and briquette coal improve under confining pressure, but the internal difference in the raw coal is significantly reduced. The cohesion of the raw coal sample initially increases and then decreases with increasing water content, and the internal friction angle increases with increasing water content. In addition, it is verified that the strength, cohesion, elastic modulus, and deformation modulus of the briquette decrease with increasing pore pressure under different pore pressures, but the strength difference of the class III–V coal decreases under increasing pore pressure. Based on the abovementioned results, the strength parameters of a coal body are estimated using the Hoek–Brown (H–B) criterion. Based on a comparison of the strength parameters of the coal sample and coal body, the estimated strength parameters of the coal body are closer to the actual values on site.

Utilization of steel plant waste and by-products in reactive coke making

Coke is used in the blast furnace as a fuel. To produce the coke, metallurgical coals are blended in the coal blend. But the reserves of the coking coals are limited in India. Hence, there is a need to use the non-coking coals in the blast furnace. However, there is a limitation for use of non-coking coals in the coal blend for coke making. So, an attempt was made in this study to increase the amount of non-coking coals in the coal blends. In the present work, briquetting technique was used for producing briquettes having non-coking coal up to 40%, and rest is slightly coking coal along with reactive materials and binders. Those samples were compressed in a hydraulic press to form briquettes which were then carbonized. The strength and reactivity tests of those coal briquettes were carried out to determine the optimum addition proportion of reactive materials and binders. It was found that 10% of reactive material was optimum for briquette making. The use of coal tar pitch and petroleum pitch binders were also studied, and their optimum values were obtained as 3%. It was also found that coal briquettes comprising of LD (Linz-Donawitz) slag and iron oxide exhibited higher reactivity as compared to other reactive materials.

Laboratory research of coal briquette quality indicators

The research is based on the results of scientific research on the development of technology for the production of high-energy and environmentally friendly coal briquettes.The study of crushing of different sizes of coal, as well as the study of separation processes on the geometric size of the fine fraction of coal revealed high efficiency of hammer grinders and multi-layer screening devices for sorting, based on the consistency of briquette constituents, a technological system for the production of briquettes based on the use of a solution of biohumus and rice starch as effective biobinders, providing effective interaction of coal particles. The strength of briquettes obtained by increasing the amount of starch solution in coal compounds by 2%, 4%, 6% is 1.3-1.5 times, and when the pressing pressure is increased from 5 MPa to 40 MPa, the average strength of briquettes is from 2.8 MPa to 6.4 MPa. increase was detected.

PENGARUH VARIASI TEKANAN PADA MODIFIKASI BRIKET BATUBARA TERHADAP WAKTU SULUT

Briquettes are alternative energy that can be used as substitutes of petroleum and gas. Coal briquettes generally have a slowignition time. Therefore, this study modifies coal briquettes by adding a blazingstimulant of palm frond fiber and potassium chlorate. The objectives to be achieved in this study wereto find out the effect of pressure variations modificationsof coal briquettes to the ignition time. In this study, the briquetting process was done by varying pressure of 200 Psi, 300 Psi, 400 Psi, 500 psi and 600 Psi. Coal briquette powder particle size used in this study was 80-100 mesh while the particle size of oil palm frond fibers used were 40-50 mesh. The results showed that the fastest ignition time obtained at a pressure of 200 Psi with ignition time 132 seconds. In conclusion, the pressure variations on coal briquettes modifications infunced ignition time.
 

Adsorption of Activated Carbon from Coal on Coal Briquette Combustion Flue Gas

Coal briquette is expected to be able to become low-cost alternative energy source. However, coal briquette combustion produces gas emission such as SO2, NOx, CO, and CO2 that cause air pollution. The objective of this research is to minimize flue gas emission by using activated carbon made from low level coal such as lignite, obtained from South Sumatera. Activated carbon formation is conducted by using chemical activation method, with ZnCl2 composition variations of 25%, 30%, 35%, 40%, and 45% and coal grain size of 40 mesh, 60 mesh, 80 mesh, and 100 mesh. Carbonization process was conducted at 500°C for 2 hours. Carbonization was conducted by using an air tight steel box infused by nitrogen along the process. The result of this research shows that the composition of ZnCl2 40% and coal 60% with 80 mesh of coal grain size, is the optimum condition to produce activated carbon with highest iodine value of 1323 mg/g. in the application of coal briquette flue gas adsorption experiment, the activated carbon is highly effective in absorbing NO2 with adsorption volume of 87.6 - 90.8%. SO2, CO2, and poly aromatic hydrocarbon (PAH) gas adsorption levels are varied from 27% to 47.8%, but not really effective in absorbing CO gas with adsorption capacity of 11.5%. The activated carbon utilized in this research has the potential to be developed as effective adsorbent for coal combustion exhaust gas emission.

Experimental study on the role of moisture in the cold binderless briquetting of low-rank coal

ABSTRACT Briquetting is needed to complete the upgrading process of low-rank coal, which commonly produces yield in a powder form. The process increases solid fuel’s energy density, handling, and transportability. The binderless briquetting is frequently selected over the conventional briquetting process since it utilizes the coal substance to bind the particle such that the coal property as fuel is unaltered. Unfortunately, the mechanism of how the coal particles are bonded remains unclear. This research investigated the binderless briquetting process at room temperature (cold binderless briquetting), employing moisture content (MC) as a binding agent. Experimental results show that, during the compaction process, the moisture acts as lubricants and provides deformability in the coal particle, which eases the particle interlocking at a higher density. However, the change of moisture in the briquette after the compaction process could induce swelling and shrinkage in the particle, causing a discrepancy in the particle interlocking system and reducing the briquette strength. From the investigation, the cold binderless briquetting of LRC is recommended to be conducted at 2500 bar compaction and using coal particles with the initial MC of 10–20%. The prediction of briquette strength at different moisture content is also proposed in this paper.

Drivers and Hindrances to Substituting Wood Fuel with Briquettes Coal in the Minawao Nigerians Refugees’ Camp

The objective of this article was to assess the level of substitution of wood fuel with briquettes in Minawao refugees’ camp. The chosen methodology combines survey tools for data collection and practice. The results show that the refugees need 18,339 tons of wood fuel that must be substituted by 19,654 tons of biomass briquettes per year. Thus, since the promotion of briquettes coal in Minawao camp, the largest annual production is roughly 75 tons, covering 0.38% of household cooking energy needs. Today, more than 43% of refugees’ households have integrated the briquettes use, but they don’t have enough tools and biomass to make that much. Within a radius of 12 km around the refugee’s camp, the amount of different biomass residue is estimated to 243 ± 1 tons, that produce 111 ± 1 tons of briquettes, which could cover 0.56% of refugees’ households needs. All this shows that the refugees will not stop putting pressure on Zamay forest reserve to collect firewood. Thus, it is important to supply refugees with rice husks from SEMRY and scraps wood from sawmill in eastern region of Cameroon and equip them with materials of briquettes making. The implementation of these actions requires financial means. Keywords: Driver, hindrance, substitution, wood fuel, briquette coal, Minawao refugee Camp DOI: 10.7176/JETP/12-4-03 Publication date: October 31 st 2022

Manufacturing high-performance formcoke from pulverized coal using potato residue-based biomass binders

Formcoke is a more favorable and cleaner fuel than coal because of its high carbon content, high calorific value, and low ash content. The identification and sourcing of high-performance, cost-effective, and green binders for formcoke production from pulverized coal are required but remain a big challenge. Herein, potato residue was composited with magnesium chloride as a bio-based composite binder for the production of high-performance formcoke. The compression strength of the obtained formcoke was determined as 1967 N. The calorific value of the formcoke was in the same range as lumpy coal. Furthermore, the formcoke exhibited higher thermal stability and required more activation energy in the combustion process than briquette coal and pulverized coal. In addition, the pollutant emissions of the formcoke such as carbon dioxide, sulfur dioxide, hydrocarbons, and other pollutants of the combustion process were significantly less than those of pulverized coal. This research uses potato residue as the primary raw material to prepare a bio-based composite binder for the production of high-performance formcoke with the advantages of a simple manufacturing process, abundant availability, low price, and excellent performance. It provides a new application of potato residue and a high-performance binder preparation method for the production of high-performance formcoke.

Potential Alternative Energy of Hybrid Coal from Co-pyrolysis of Lignite with Palm Empty Fruit Bunch and the Kinetic Study

Lignite is classified as a low-rank coal due to its low content of calories. Co-pyrolysis with biomass waste such as palm empty fruit bunches (EFB) here can be used to increase lignite’s economic value. The mixture of these two materials can produce an alternative energy source called hybrid coal (HC). This study aims to determine the optimum temperature for co-pyrolysis of lignite and EFB as well as characterize liquid (tar) and solid product (HC). Its kinetic study was evaluated as well. A raw material of 200 grams with a composition of 22.5% (w/w) EFB to lignite was put into a reactor to react at a temperature range of 300-450oC for 1 hour. To form hybrid coal briquettes (HCB),tapioca adhesive with a concentration of 6% (w/w) was added to the solid product (HC). The results showed that the tar yield increased with increasing temperature from 300 to 450oC. Similarly, the calorific value of HC increased by 14.50% as also occurred in other physical properties of HC. Meanwhile, the kinetic study revealed that the model was well-fitted to the data, and confirmed the obtained results. Thus, this research can support the development of affordable alternative energy to be implemented in large-scale production.