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In this study, sequential feeding method was conducted due to some coal-fired power plants not being equipped by coal blending facility. Its effect on ash-related problem was investigated using drop tube furnace combustion test and ash particle observation method. AUS coal (low-slagging risk sample) and KT coal (high-slagging risk sample) were used to obtain AK-1 coal and AK-2 coal. AK-1 coal was a coal sample of out-furnace blending method, while AK-2 coal was coal sample of sequential feeding method. AK-1 probe tended to be more similar to AUS coal with only a small spot of ash attached on the probe surface. Meanwhile, AK-2 probe had more ash attached on the probe surface, indicating more severe slagging than AK-1 probe. According to ash morphology, the result indicated that the upper layer of slag tended to be more similar to AUS coal ash, while initial layer of slag of AK-2 coal contained more KT coal ash. Based on ash mineralogy, sodium in AK-2 coal was distributed evenly which was different with AK-1 coal. This result shows that sequential feeding method is not applicable to reduce slagging and fouling risk of KT coal. [ABSTRACT FROM AUTHOR]

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Rising coal price and increasingly stringent emission policy highlight the importance of balancing economic benefit and sustainable development of coal-fired power plants. In order to make the power plant operate economically and safely, and reduce the emission of pollutants as much as possible, this paper proposed a coal blending optimization framework for coal-fired power plants. This framework constructs a set of mathematical model based on the minimization objective function, including the economy, safety and environmental protection of coal. And a multi-strategy fusion multi-objective particle swarm optimization (MSF-MOPSO) method is proposed to optimize the coal blending model. The feasibility, effectiveness and superiority of the method are theoretically verified by convergence analysis and several sets of simulation experiments. And the practical application of this framework shows that under the coal blending strategy based on different weight combinations, the algorithm proposed in this paper can produce high-quality Pareto spatial distribution. Comparing with other state-of-the-art coal blending algorithms, this method can reduce the coal purchase cost by 4.42% and ${\rm{S}}{{\rm{O}}_{\rm{2}}}$ S O 2 emission by 5.11% at least under the same condition. It has significant environmental protection and economic benefit. [ABSTRACT FROM AUTHOR]

To realize the high‐efficiency utilization of iron‐rich coal (ZC), it is necessary to conduct in‐depth research on its ash fusion characteristics and regulation mechanism. In this paper, the fusion temperature test of ZC coal ash was first carried out in a weak reducing atmosphere, and diatomite (GZT) and Naomaohu high‐calcium coal (NMH) were selected as additives. The results show that the four characteristic temperatures of ZC coal ash are all low under weak reducing conditions. The addition of NMH ash lowered the fusion temperature of ZC coal ash, while the GZT ash increased the fusion temperature to varying degrees. When the addition ratio of NMH ash is less than 40 %, the effect of increasing the difference between the deformation temperature and flow temperature of ZC coal ash is still positive. The addition of NMH ash made the slag system generate a high content of calcium‐magnesium feldspar and calcium‐iron feldspar, decreasing the fusion temperature of the blended coal ash. The addition of GZT ash increased the content of SiO2 in the slag system and promoted the increase of the iron‐pyroxene content, and the formation of the iron‐aluminum pyroxene and cordierite mineral phases, thereby increasing the coal ash fusion temperature. [ABSTRACT FROM AUTHOR]

High sulfur anthracite has high research value and application prospects in the preparation of carbon adsorbent due to its excellent coal quality conditions, but the pore structure changes and sulfur migration dynamics in the preparation process are not clear. In this paper, using SEM, pore structure analysis, Raman, FTIR and XPS, the feasibility of preparing carbon adsorbent from high-sulfur coal blending was analyzed from the perspective of apparent morphology, pore structure parameters, graphite crystal structure, and functional groups and content, while the occurrence form of sulfur in carbon adsorbent was explored. The results showed that the carbon adsorbent prepared from high-sulfur anthracite was mainly microporous, and the specific surface area was up to 1103.23 m2/g, which was the highest among the known high-sulfur coal materials. The degree of disorder of raw coal and the size of graphite crystal particles synergistically formed a rich pore structure. Sulfur in coal mainly exists in the form of thiophene and sulfide. An increase in the bituminous coal proportion promotes the transformation of carbon adsorbent to an alkaline environment. Thiophene sulfur is removed at 900°C, and sulfide is transformed into sulfoxide and sulfone under steam oxidation and Fe catalysis. [ABSTRACT FROM AUTHOR]

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Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Some ash related problems, such as slagging at furnace bottom and fouling at the air pre-heater surface, are frequently encountered during circulating fluidized bed gasification (CFBG) of Zhundong coal. Low ash fusion temperatures (AFTs) and intense sodium release should be responsible for those problems. In industry, coal blending is deemed to be a feasible method to both improve AFTs and control sodium release. In this work, Wuhai coal was selected as blending coal. The ratio is varied from 0% to 40% by mass with 10% interval. The mixed samples were gasified by steam at 950°C in a lab-scale furnace. Some key indices, such as sodium release behaviors, ash slagging characteristics and char gasification performances, were investigated by ICP-OES, AFTs, XRD and TG analyzers, respectively. The results indicated that coal blending could significantly decrease sodium release behaviors. For ash slagging characteristics, it is surprised to find that three out of four AFTs (deformation temperature, softening temperature, hemispherical temperature) show an U-shaped correlation with blending ratio, indicating that a low ratio possibly causes more severe ash slagging problem. It is ascribed to the formation of substantial percentage of fusible Na-containing silicates and aluminosilicates. In addition, coal blending greatly increases ST-DT, implying that the ability of resistance to bed temperature fluctuation is markedly enhanced. Due to the high level of alkali and alkaline species, the synergistic effect is clearly observed during co-gasification. Taking all key indices into consideration, 30% blending ratio of Wuhai coal is recommended. [ABSTRACT FROM AUTHOR]

This work investigated the effect of coal blending on ash fusibility and slurryability of Xinjiang low-rank coal. The results showed that Xinjiang low-rank coals were characterized by high internal water content, high volatile content, high ash fusing point, and poor slurryability, which can not be directly used in coal water slurry gasification. The blending method not only reduced the ash fusibility but also improved the slurryability of these low-rank coals. When the coals with low calcium and high silicon contents (KG and YK) were blended with coal with high calcium content (SH), the ash fusion temperatures of the blended coal were significantly reduced. Moreover, the SH coal showed the worst slurryability performance with a concentration of 48.56%. The slurryability of HS coal can be dramatically improved by blending with KG. When the mass fraction of KG coal reached 70%, the concentration of coal water slurry increased by 11%. For the blended coal of KG and YK, the concentration and stability of coal water slurry gradually increase with the increasing mass ratio of KG. The coal blending method can effectively improve the concentration of coal water slurry for the low-rank coals, which were difficult-to-prepare slurry. [ABSTRACT FROM AUTHOR]

A novel method has been developed to estimate coke reactivity index (CRI) from coal properties through a kinetic approach. The model was derived from mass balance with a kinetic model of batch reactor CRI test. The parameters of kinetic model were optimized using non-linear least squared method. Three main properties of coals, i.e., Fe2O3 content, volatile matter, and coal rank were selected to predict the CRI. The predicted CRI value was in a good agreement with the CRI data. The standard error was less than 5. Coke strength after reaction (CSR) was predicted using linear regression of the CSR and CRI data. The estimated CSR was in good agreement with the CSR data. The sensitivity analysis of coal properties to CRI was also performed using the developed kinetic model. The model was successfully applied for coal blending to predict CRI of the produced coke with standard error 3.7. This model can explain well the catalytic effect of coal and coal blend properties to coke reactivity during the CRI test. [ABSTRACT FROM AUTHOR]

Summary: The substitution of coal blending with sawdust had been widely investigated for metallurgical coke production. In this paper, the physiochemical structures of the semicoke derived from sawdust/coals blends co‐coking were characterized by several analytical techniques including FTIR‐ATR, XPS, NMR, OM, and SEM. Meanwhile, the influence of the sawdust on the physicochemical properties of the sawdust/coals blends were also investigated. Results indicated that partial substitution of coal blending with sawdust benefited from the formation of colloid and optical anisotropy due to the positive synergetic effect, whereas high proportion of sawdust (>10 wt%) inhibited the agglomeration of semi‐coke. On the other hand, the semicoke consisted primarily of aromatic carbons replaced by the oxygen linked to carbons and aliphatic carbons when the coal blending was replaced by high proportion of sawdust, causing a less polyaromatic graphite‐like structure formation in the semicoke. [ABSTRACT FROM AUTHOR]

A novel approach to robust optimization of coal blending operations is proposed. While many rigorous mathematical approaches have been developed for this problem in the past, most neglect the uncertainty associated with both the inherent coal quality attributes as well as the sampling and measurement protocols used to measure those attributes. This uncertainty may lead to the imprecise estimation of quality values and force operators to adopt a conservative blend strategy based on safety factors and simple heuristics. One promising approach to rigorously address this shortcoming is through robust optimization (RO), a unique approach to handle data with uncertain and unspecified statistical distributions. In the current work, we first derive a deterministic optimization problem using the premium/penalty structure in typical coal sales contracts. This formulation is then translated to a robust formulation and solved as a Mixed Integer Nonlinear Program (MINLP). A numerical example is presented to demonstrate the utility of the method and to compare the deterministic solution, as the most optimistic and risky blending plan, with the RO solution, as the more pessimistic, yet robust, plan. The proposed strategy can help decision-makers achieve the economic and strategic goals of the operation at acceptable risk levels. [ABSTRACT FROM AUTHOR]

Coking coal is essential for the production of steel, and the quality of this coal significantly contributes to the quality of the produced steel. High quality coking coal has low ash content and a range of properties including volatile matter content and predicted coke strength. The coal is improved by processing after it has been mined. This processing varies and coal from multiple sources is blended. This paper introduces an original mixed integer programming model to maximise the profit of coal blending and processing. The model is computationally efficient and can be implemented at any coal mining and processing operation. The multi-period blending model incorporates stockpiling of raw material, and explicitly captures the geological variability of coal using chance constraints. A case study is evaluated and demonstrates that explicitly modelling geological variability can reduce the risk of breaching product specifications without any revenue loss. The improvement is achievable, without additional cost, by selecting the order that coal is fed into a processing plant. [ABSTRACT FROM AUTHOR]

Using low- or zero-carbon fuels is necessary to reduce CO 2 emissions. Gas reburning technology can be applied to existing coal boilers to reduce not only CO 2 but also NO x emissions. In this study, we confirmed the gas reburning effect using lab-scale equipment based on the consumption coal used in real-scale boilers, with the aim of practical application. Bituminous coal was used as the reference fuel, and sub-bituminous coal was blended to determine whether coal blending has an effect on NO x emissions. This was conducted to optimize the coal blending ratio and gas reburning technology for NO x emission reduction and quantify the NO x reduction by the two methods. Blending sub-bituminous coal reduced the unburned carbon (UBC) content, because of its high volatile matter content. Moreover, NO x emissions decreased as the ratio of sub-bituminous coal increased. In terms of the reburning effect, although UBCs increased with the addition of methane, NO x emission decreased by up to 96.05 %. The conversion ratio, defined as the NO x formation ratio of the total fuel N injection, was used to separate the NO x reduction effects of the two methods. Thus, gas reburning in the ammonia co-firing system of coal-fired power plants can significantly reduce NO x emissions. • NO x reduction by coal blending and reburning were described separately using CR. • Methane reburning can dramatically reduce NOx emissions. • Reburning gives insight for NOx reduction during ammonia co-firing plants. [ABSTRACT FROM AUTHOR]

Copyright of Energy Chemical Industry is the property of Energy Chemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Experimental research was carried out on the manufacturing of bio-coal briquettes from a blend of two different types of low-quality coal and biomass waste in the absence of coal carbonization, where the third blend of the material was fermented by adding a bio-activator solution before pressurizing the components into briquettes. The coal samples from Caringin–Garut Regency (BB–Garut) had a low calorific value and a high sulfur content (6.57 wt%), whereas the coal samples from Bayah–Lebak Regency (BB–Bayah) had a higher calorific value and a lower sulfur content (0.51 wt%). The biomass added to the coal blend is in the form of fermented cow dung (Bio–Kohe), and it had a calorific value of 4192 kcal/kg and a total sulfur content of 1.56 wt%. The main objective of this study is to determine the total decrease in the sulfur content in a blend of coal and biomass in which a fermentation process was carried out using a bio-activator for 24 h. The used bio-activator was made from Garant® (1:40) + molasses 1 wt%/vol, and its used amount was 0.2 L/kg. Also, the total sulfur content in the blend was 1.00 wt%–1.14 wt%, which fulfills the necessary quality requirements for non-carbonized bio-coal briquettes. The pyritic and sulfate content in the raw coal was dominant, and the organic sulfur, when fermented with Garant®, was found to be less in the produced bio-coal briquettes by 38%–58%. [ABSTRACT FROM AUTHOR]

Coal blending is an effective method to reduce the slagging tendency. The mineral transformation within blended coal ashes has an important influence on the slagging behaviors, which have been well studied under conventional air-fuel condition. Oxy-fuel combustion is recognized as one of the most promising CO 2 reduction technologies. However, the mineral transformation within blended coal ashes in oxy-fuel condition has yet to be fully understood. This work is aimed to comprehensively study the influence of CO 2 atmosphere on Ca -containing mineral transformation behaviors during a Ca dominated coal co-firing with a Si/Al dominated coal in O 2 /CO 2 condition by TG-DSC, XRD and HSC simulation. These results show that the atmosphere significantly affects on the transformation of Ca -containing mineral and the final existing form of Ca in the blended coal ashes. When the high content Ca coal is blended with the high content Al/Si coal in the O 2 /CO 2 atmosphere, the CO 2 promotes the transformation of Ca into CaCO 3 and Ca under low temperature mainly exists in the form of CaCO 3 (little CaSO 4) in the blended coal ashes. CaCO 3 under high temperature is decomposed to produce highly active CaO, and CaO reacts with Al/Si to form the low melting point minerals, which may aggravate the slagging tendency. The present study can provide useful information to reduce the slagging behavior of the blended coals in the O 2 /CO 2 atmosphere. • Ca -containing mineral transformation of blended coal oxy-fuel combustion is studied. • The atmosphere affects the final Ca- existing form within blended coal ashes. • The CO 2 in O 2 /CO 2 promotes the transformation of Ca into CaCO 3. • CaCO 3 is decomposed to produce highly active CaO under high temperature. • CaO– Al/Si reaction produces low melting point mineral to aggravate the slagging. [ABSTRACT FROM AUTHOR]

Biomass was used as additives in coal blending for making coke in terms of widening the alternative raw materials and reducing CO 2 emissions. To obtain the influences of biomass incorporation on the semicoke formation, the chemical structure transformation as well as the gas evolution during sawdust (SD)/coal blending (BC) co-coking were investigated using in-situ Fourier transform infrared spectroscopy coupled with mass spectrometry (In-situ FTIR-MS). Meanwhile, the role of biomass in the semicoke formation was also characterized by several analytical techniques. The transformation of the five main functional groups between SD and BC exhibited the largest difference, and the synergistic effect based on the chemical structure transformation was also proposed for the SD/BC blends co-coking. The synergistic effect based on the chemical structure transformation was divided into two stages during semicoke formation. One stage occurred at 100–280 °C that was assigned to the physical effect that inhibited the BC decomposition. Another stage happened at 280–500 °C that was mainly attributed to the hydrogen transfer that enhanced the aromatization of semi-coke. In addition, it was also noted that the thermoplastic properties decreased proportionately to the quantity of the SD, and the non-agglomeration between BC and SD was clearly observed by SEM. ● The co-coking of SD/BC was investigated using In-situ FTIR-MS. ● The differences of chemical structure between SD and BC were observed. ● The synergistic effect during semicoke formation process caused by two stages. ● The thermoplastic properties decreased proportionately to the quantity of the SD. ● The non-agglomeration between BC and SD was clearly observed by SEM. [ABSTRACT FROM AUTHOR]

Many developing countries are opting to rely on coal-fired power mainly due to the abundance of the resource and its economic viability, since the capital needed to build a new coalfired power plant is not as large as a nuclear power plant. Compared to nuclear power, coal-fired power does not bear the risk of major catastrophe and therefore it will be relevant in the power industry for many years to come. However, the major drawback of coal-fired power plant is the fact that it is not a clean energy prospect and it is considered one of the main contributors to the world's greenhouse gases. Coal combustion is usually associated with the emission of greenhouse gases such as CO, CO2, NOx, and SO2. One of the main objectives of coal combustion research is to develop techniques that will help power plant operators to utilize coal cleanly and efficiently by adopting coal blending practices. Currently, emission mitigation and boiler cleanliness issues through coal blending process are focusing more on laboratory scale tests and not utilizing actual plant data and behaviour. This study evaluates the effectiveness of the implementation of Coal Combustion Prediction Analysis Tool (CPAT) as a tool to facilitate power plant operator in predicting the impact of individual or blended coal quality. It will provide early predictions on boiler combustion performance related to the coal quality and it will assist the power plant operators preparing for boiler process control optimization. This study will also discuss slagging and fouling factor of different coal type, which are used in one coal-fired power plant in South East Asia. [ABSTRACT FROM AUTHOR]

India has vast coal resources all over the country; however, the presence of high ash content makes them invulnerable for industrial usage. To compensate for the rapid depletion of high-quality coking coals and to compensate for the demand for coal in iron and steel sectors, coal cleaning or beneficiation and blending techniques have come into limelight for the usage of low-quality coal. In this paper, laboratory-scale experiments were performed on the utilization of Indian high ash non-coking coal (NCC) and imported semi-coking coal (SCC) for the coke preparation. At first, washability characteristics of Indian high ash coal were investigated by using jigging, spiral concentration, and sink and float density separation methods. The optimum cut-off density NCC and SCC coals were blended and sent for the caking properties analysis. Proximate and ultimate analysis, vitrinite reflectance, crucible swelling number, and caking index or roga index have been taken as the measure for the caking ability of coal blends. [ABSTRACT FROM AUTHOR]

The modifications in the low ash fusion temperature (AFT) of Xiangyang coal (XY) were investigated by blending it with three high AFT coals [Jincheng coal (JC), Sunjiahao coal (SJH), and Shajuzi coal (SJZ)], respectively. These three coals all improved XY AFT effectively. With the JC mass ratio varying from 0 to 50%, the AFT of XY/JC gradually increased. The AFT of XY/SJH increased significantly (0–30%), slowly (30–40%), and rapidly (40–50%) with increasing SJH content. For SJZ, the AFT of XY/SJZ increased quickly (0–30%) and very slowly (30–50%). For XY entrained-flow gasification, the appropriate blending ratios of JC, SJH, and SJZ were 40–50%, 30–40%, and 20–40%, respectively. X-ray diffraction, scanning electron microscopy, and FactSage thermodynamic calculation were applied to investigate the effects of mineral transformation on AFT. Quartz (SiO2), anorthite (CaAl2Si2O8), diopside (CaMgSi2O6), and hedenbergite (CaFeSi2O6) were detected in XY ash at 1100 °C. As the mass ratios of high AFT coals increased, the obvious increase in anorthite content led to the rise in the AFT of XY/JC; mullite (Al6Si2O13); and corundum (Al2O3) with a high melt point formed in ashes causing the increase in the AFTs of XY/SJH and XY/SJZ, respectively. [ABSTRACT FROM AUTHOR]

In order to expand the range of bituminous coal injected into blast furnace, the ash melting behavior and regulation mechanism of bituminous with high calcium and low ash fusion temperature (AFT) were investigated by coal blending. And the mineral transformation behavior in the blended ashes was investigated by X‐ray powder diffractometry with normalized reference intensity ratio software and FactSage software. The experimental results manifest that the softening temperature (ST) of coal D is 8°C lower than that of the hot blast temperature. By adequately mixing coal B and coal D, it is easy to meet the requirements of pulverized coal injection. And coal D has become a standard bituminous for blast furnace injection. However, the high content of CaO in the coal S ash makes the AFT much lower than the hot blast temperature, which leads to the reluctance of the steel industry to inject coal S. With the increase of coal B mass ratio, the content of high‐melting eutectic matters (3Al2O3·2SiO2 and tridymite) increases at high temperature, while the content of low‐melting anorthite, andradite, gehlenite, and grossularite decreases, which leads to the increase of AFTs. The variation in the liquid phase under certain conditions reflects the change in AFT. In summary, by blending with coal B, the ST of blended coals S/B is higher than the hot blast temperature (1250°C), so that coal S can be applied to blast furnace injection. And the injection ratio of coal S in blended coals can reach about 50%. [ABSTRACT FROM AUTHOR]

The idea of this paper is to properly utilize Indian low-rank coking coal (semi-coking coal) with the blending of high-rank imported coals and to reduce the overall cost of coke making. The blending of the coals has been done in two phases. Effect of blending mass ratio on the swelling index and plasticity parameters has been studied. The effect of maceral content, vitrinite reflectance, and volatile matter content on the caking ability of coals has been studied. Blended sample analysis shows that there is an abrupt drop in the fluidity of the samples compared to the original coals; there is no proper relation between the fluidity and swelling index of the coal blends. Phase 1 coal blends show better results compared to phase 2 samples. Crucible swelling number values for blend 1 and blend 3 from phase 1 are 6 and 4.5, respectively. To validate the swelling number, coke strength after reaction (CSR) and coke reactivity index (CRI) tests have been done for blend 1 and blend 3 coals from phase 1. CSR, CRI for blend 1 and blend 3 samples are 22.18, 71.30 and 23.79, 70.75, respectively. [ABSTRACT FROM AUTHOR]

Due to the continuous improvement of industrial production requirements and green manufacturing demand, manufacturing enterprises and factories need to constantly optimize and improve the system structure. Based on the actual problems in the actual coal blending process, this paper analyzes the reason of the coal blending error in coal blending process and the optimization scheme of intelligent control of coal blending process. We optimized the overall structure of the coal blending system, improved the coal blending system which use the fuzzy control system. At the same time, we used MATLAB to simulate and analyse the simulation results. This paper gives an illustration to the optimal structure and system of the coal blending system, effectively improves the accuracy and stability of the coal blending process control system, reduces the coal blending error and improves the quality of coal blending in general. [ABSTRACT FROM AUTHOR]

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Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hardgrove Grindability Index (HGI) is a determining factor of energy consumption during grinding. The current study is aimed at investigating the influence of the blending behavior on HGIs of two dissimilar coal samples. In this study, one local coal sample is taken from Lakhra coal deposits and second sample is extracted from Indonesian coal reserves for empirical experiment and analysis. The total number of nine blends with different blending ratios based on the Net Calorific Value (NCV) was made. In addition, the samples were further tested for proximate and ultimate analysis, Gross Calorific Values and HGI respectively. The ASTM D409-D409M standard Hardgrove grindability tester was used for the determination of HGI of cited two coal samples. The main purpose of this study is to determine the blends that specify the optimum results those are appropriate for power sectors and cement industries. According to the above study, the blend no 2 and 3 demonstrate the optimum results for cement factories with approximately HGI 46 and 49 with sulphur content 1.01 and 1.17, whereas blend no 4 and 5 are appropriate for power sectors with approximately HGI 52 and 54 with sulphur content 1.37 and 1.58. Furthermore, the value of the blends for HGI and moisture content shows the inverse relation, as the moisture content increases HGI value decreases. Similarly, research results also determine that there is also inverse relationship between the blend value of volatile matter and total carbon with HGI. Additionally, the GCV also exhibits inverse relationship while ash and fixed carbon reveal direct relationship with the value of blends for HGI. In the same manner, sulfur also exhibits direct relation with HGI value.. [ABSTRACT FROM AUTHOR]

Hardgrove Grindability Index (HGI) is a determining factor of energy consumption during grinding. The current study is aimed at investigating the influence of the blending behavior on HGIs of two dissimilar coal samples. In this study, one local coal sample is taken from Lakhra coal deposits and second sample is extracted from Indonesian coal reserves for empirical experiment and analysis. The total number of nine blends with different blending ratios based on the Net Calorific Value (NCV) was made. In addition, the samples were further tested for proximate and ultimate analysis, Gross Calorific Values and HGI respectively. The ASTM D409-D409M standard Hardgrove grindability tester was used for the determination of HGI of cited two coal samples. The main purpose of this study is to determine the blends that specify the optimum results those are appropriate for power sectors and cement industries. According to the above study, the blend no 2 and 3 demonstrate the optimum results for cement factories with approximately HGI 46 and 49 with sulphur content 1.01 and 1.17, whereas blend no 4 and 5 are appropriate for power sectors with approximately HGI 52 and 54 with sulphur content 1.37 and 1.58. Furthermore, the value of the blends for HGI and moisture content shows the inverse relation, as the moisture content increases HGI value decreases. Similarly, research results also determine that there is also inverse relationship between the blend value of volatile matter and total carbon with HGI. Additionally, the GCV also exhibits inverse relationship while ash and fixed carbon reveal direct relationship with the value of blends for HGI. In the same manner, sulfur also exhibits direct relation with HGI value. [ABSTRACT FROM AUTHOR]

Based on this study, the Al2O3 content of Jungar coal ash is over 45%, and the resistivity of high-Al2O3 ash in Jungar reaches up to 1012 Ω​·cm. These results seriously influenced the electric characteristics of fly ash, and the collection efficiency of electrostatic precipitators (ESPs) evidently decreased. To facilitate the effective collection of fine particle in the flue gas generated before and after coal blending via ESP, the fly ash obtained from a power plant electrostatic precipitation was analyzed in terms of resistivity, size distribution, and cohesive force through a portable dust electrical resistivity test instrument, Bahco centrifuge, and a cohesive force test apparatus invented by the researchers. The mixed ratio of else coal is higher than 50%, the resistivity of the fly ash in the flue gas was lowered to approximately two orders of magnitude, and the size distribution showed an evident decrease in the PM2.5 and PM10 content in fly ash. In addition, the adhesive force and efficiency increase from 95.9 to 99.5% in the electrostatic precipitation. Therefore, the combustion of blending coal is an effective approach to improve the efficiency of ESP used to collect high-Al2O3 fly ash. [ABSTRACT FROM AUTHOR]

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Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Tampa Electric Company (TECO), which serves 687,000 customers in Florida, generates 60 percent of its electricity using coal-fired generators. To meet environmental regulations on the emission of coal combustion, it must carefully mix several fuels of different qualities to make safe, environmentally friendly, and affordable blends that are generator specific. We worked with the management and engineering teams at TECO to develop a decision support platform, which centers around a mixed-integer programming (MIP) model to comprehensively capture system specifications, requirements, and operations in all key aspects of TECO's fuel supply chain. This platform enables TECO to make optimal procurement, transportation, blending, and burn decisions and satisfy all environmental regulations. We estimate that the implementation of this model can provide TECO with annual fuel-cost savings of 2-3 percent, which translate to millions of dollars of savings in total fuel costs. [ABSTRACT FROM AUTHOR]

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Many power plants use blend coals to replace design coal for burning due to economic reasons. These blend coals are usually blended by two types of off-design coal, so there is a need to select the off-design coals and to optimize the blend ratio. In this process, an important problem is how to estimate the properties of the blend coal, especially for the softening temperature (ST) of coal ash. To deal with this issue, this article combined support vector machines (SVM) and genetic algorithms (GA) to predict coal ash's softening temperature (ST) from a given ash composition. An SVM model was built for predicting the ST of coal ash, and its parameters were optimized using GA. The SVM model was trained and verified using experimental data from 12 coal samples and subsequently was tested using data from 17 blended coal samples. The results confirmed the validity of the SVM model, which accurately predicted the ST for all these coal samples. Based on the SVM model, a coal-blending system was developed for a given 300 MW power plant boiler. The blend coals designed by this system met the firing requirements of the boiler and achieved high thermal efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Coal blending is an effective way to organize and control coal ash fusibility to meet different requirements of Coal-fired power plants. This study investigates three different eutectic processes and explains the mechanism of how coal blending affects ash fusibility. The blended ashes were prepared by hand-mixing two raw coal ashes at five blending ratios, G:D = 10:90 (G10D90), G:D= 20:80 (G20D80), G:D = 30:70 (G30D70), G:D = 40:60 (G40D60), and G:D = 50:50 (G50D50). The samples were heated at 900 °C, 1000 °C, 1100 °C, 1200 °C, and 1300 °C in reducing atmosphere. XRD and SEM/EDX were used to identify mineral transformations and eutectic processes. The eutectic processes were finally simulated with FactSage. Results show that the fusion temperatures of the blended ashes initially decrease and then increase with the blending ratio, a trend that is typical of eutectic melting. Eutectic phenomena are observed in D100, G10D90, and G30D70 in different degrees, which do not appear in G100 and G50D50 for the lack of eutectic reactants. The main eutectic reactants are gehlenite, magnetite, merwinite, and diopside. The FactSage simulation results show that the content discrepancy of merwinite and diopside in the ashes causes the inconsistent eutectic temperatures and eutectic degrees, in turn decrease the fusion temperature of the blended ash and then increase them with the blending ratio. [ABSTRACT FROM AUTHOR]

In this paper, we formulate and solve a real life coal blending problem using a Column Generation Approach. The objective of the model is to prescribe optimal mixes of coal to produce coke. The problem is formulated as a mixed integer program. It involves various types of constraints arising from technical considerations of the blending process. The model also incorporates nonlinear constraints. It results in a large-scale problem that cannot be solved by classical operations research methods. Defining three heuristic methods based on column generation techniques, this paper proposes reasonable solutions for the industry. [ABSTRACT FROM AUTHOR]

In order to improve the concentration of coal water slurry (CWS) for gasification with lignite, the slurryability of three coal samples which were provided by an chemical enterprise was conducted through traditional CWS preparation process and classified grinding process. Then the CWS preparation with blending coal was carried out. The results showed that, prepared by traditional process, the highest pulp concentration of Dongming coal, Zhalainuoer coal, Baokuang upgrading coal were 48.54%, 51.76%, 56.08%. Prepared by classified grinding process, the highest pulp concentration of above three CWS were 51.72%, 54.82%, 59.21%, which were above 3% higher than the concentration of CWS prepared by traditional process. When the mass ratio of Dongming coal and Zhalainuoer coal was 1 to 1, or the mass ratio of Dongming coal and Baokuang upgrading coal was 2 to 1, the concentration of CWS were 53.12% and 54.21%, which met the design requirements. [ABSTRACT FROM AUTHOR]

To improve coke quality and decrease manufacturing cost, the gas coal, fat coal and Dongfeng coal were adopted to coke individually, which are frequent in the north of Shaanxi Province. The coke quality were analysed. Based on the results, these three kinds of coals were coked in different proportions. Determined the optimum coal blending scheme by analyzing the coke quality. The results show that, the coke quality is poor while only adopts gas coal. But the blending of gas coal increases gas production rate and coke shrinking rate. The fat coal is superior, while coking alone, the porosity of coke is high. Dongfeng coal can't coke alone, while its addition improves coke intensity and decreases superior coal consumption. When the mass ratio of gas coal, fat coal and Dongfeng coal is 1 : 6 : 3, the coke quality is the best, the pore is smaller. The coke shows silver, there is no cavernous body. The maximum thickness of plastic layer is 20. 4 mm, the final shrinkage degree is 7. 2 mm. [ABSTRACT FROM AUTHOR]

In order to expand the coking coal resources and reduce the cost of coal blending, taking the middle and high sulfur lean coal as the test sample, which is taken from No. 10 coal seam of western areas of Weibei coalfield in the southern of Erdos Basin. The middle and high sulfur lean coal contains low ash, its bond index and thickness of plastic layer is higher than that of generally lean coal, the inert and alive of petrography is close to 2, and the coking property is well. Through the coking test of middle and high sulfur lean coal, simulated coal blending of coal petrography, industrial coke oven coking test, verify the feasibility and determine the optimizations of middle and high sulfur lean coal blending coking. The results show that middle and high sulfur lean coal can be used in coal blending for coking, the blending content of middle and high sulfur lean coal should be controlled below 10%, and high content of strong caking index blending coal can enhance the thermal state index of coke. According to coal blending coking in industrial application of middle and high sulfur lean coal, show that using middle and high sulfur lean coal coking can produce quality qualified coke blending ratio of 3%~7%, expand coking coal resources and reduce the cost of blending coal using middle and high sulfur lean coal coking. [ABSTRACT FROM AUTHOR]

The analysis of raw coal supplied to Lijiahao coal preparation plant show that, it's low-medium ash and sulfur, extra low phosphorns, high calorific value non-caking coal and long flame coal. There are lots of gangue in raw slime and the gangue is easy to degrade, so it needs to minimize the contact time between coal, gangue and water during separation. The ash of secondary slime is 74.23%,the gangue degrade seriously and mainly exist in -0.045 mm fine slime. Transform the coal preparation plant by improving management, reforming coal handing equipments, adding supplement coal system, fine slime and gangue discharging systems. After transformation, the raw coal moisture reduces by an average of 3%, the supplement of high-quality coal can improve the coal delivery situation in raw coal bunker, products bunker and coal handing equipments. The fine slime can be recycled rapidly, the calorific value of lump clean coal and mixed slack coal can be improved obviously, the coal preparation plant increases profits 3 x 107 yuan per year. [ABSTRACT FROM AUTHOR]

To prepare high intensity and desulfurized active coke, using Taixi anthracite as the main raw material investigate the influence of formulation of raw material coal, activation time and steam velocity on the preparation. The results show that, using pure clean anthracite as raw material, when the activation temperature is 850 °C, the activation time is 15 minutes, steam flow rate is 6.2 mL/min, the maximum iodine value of activated coke sample is 356 m/g, the minimum intensity is 99.18 percent. The desired iodine value ranges from 300 mg/g to 400 mg/g, the intensity should be greater than 99 percent. So it is good preparation technology parameters of activated coke. When the mass ratio of Taixi anthracite and other type of coal is 75 : 25, activation temperature is 850 °C, the activation time is 15 minutes, steam flow rate is 4 mL/min, the iodine value of activated coke sample is 320 mg/g, the intensity is 99.2 percent, the adsorption properties of activated coke and wear-resisting performance are the best. [ABSTRACT FROM AUTHOR]