Reduction In Ash Content Research Articles

Improving the yield of ultra clean coal by adding acetic acid and propionic acid in selective agglomeration

ABSTRACTIn this study, ash content lower than 1%, the ultraclean coal, using anthracite coal, is prepared by selective agglomeration flotation. ultraclean coal with lower ash is needed as electrode material and solid fuel, aim of obtaining lower ash content of ultraclean coal, dispersant is usually used to reduce ash content, but the yield will decrease. Therefore, clean coal yield can be further increased by regulator. For this purpose, the effects of stirring speed; dispersant (sodium hexametaphosphate) dosage, kerosene dosage, organic regulator (butyric acid; propionic acid; acetic acid; fumaric acid; maleic acid; ethylenediaminetetraacetic acid) on yield and ash content of clean coal were investigated in the experiments. The analyses of zeta potential, contact angle, x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), x-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), and Fourier transform infrared spectroscopy (FTIR) were used to illustrate the performance of the process. The results showed that the sodium hexametaphosphate and stirring speed had a significant effect on the reduction of clean coal ash content. Furthermore, adding acetic acid and propionic acid can improve the clean coal yield without increasing the clean coal ash content. Acetic acid was used as regulator, the yield of clean coal increased by 19.42%. At the same time, acetic acid and propionic acid are proposed as a method to produce microbubbles. This important discovery provides an optional method to obtain more target products for fine mineral flotation.

Analytical and microwave pyrolysis of empty oil palm fruit bunch: Kinetics and product characterization

This study is focused on kinetics and product distribution from untreated empty oil palm fruit bunch (EOPFB) biomass and treated EOPFB using analytical pyrolysis combined with gas chromatograph/mass spectrometer and Fourier transform infrared spectrometer, and microwave pyrolysis. Industrial water wash led to significant reduction in ash content of EOPFB from 5.9 wt% to 0.7 wt%. Isothermal mass loss data collected in the temperature range of 400–700 °C showed that fast pyrolysis in the Pyroprobe® reactor followed diffusion-controlled kinetics with apparent activation energies of 30.4 and 39.6 kJ mol−1 for untreated and treated EOPFB, respectively. Analytical pyrolysis of untreated EOPFB resulted in high selectivity to fatty acids, while phenolics dominated the pyrolysates from treated EOPFB. The selectivities to phenolic compounds were 74% and 57% from treated and untreated EOPFB, respectively, via microwave pyrolysis. The higher heating values of bio-crude from microwave pyrolysis of untreated and treated EOPFB were 30.1 and 29.7 MJ kg−1, respectively.

Improving the Quality of Crop Residues by the Reduction of Ash Content and Inorganic Constituents

In this study, the mechanical size fractionation technique and the water leaching technique were applied in sequence to reduce the ash content of crop residues to target value of 6% db (dry basis) following the applicable standard. Results showed that the finest fraction of ground crop residues (< 0.25 mm) had much higher ash content than the coarser fractions, thus demonstrating that size fractionation can reduce the need for leaching as ash removal technique, and it was most effective for corn stover. For a water-to-biomass ratio (w/w) of 30, the final ash contents of the biomass materials involved in all experimental treatments were effectively reduced to below the target value. Canola straw had the highest ash removal efficiency and element removal efficiency as compared to wheat straw and corn stover. Even though the leaching condition (12 h, 25 °C) was adequate for effective ash reduction, SiO2 removal efficiency could be significantly improved when the leaching temperature was raised from 25 °C to 45 °C. A preliminary cost analysis indicated that biomass pretreatment by mechanical size fraction followed by water leaching as needed would lead to a 30% increase in the total production cost (TPC) of agro-pellets, and this is significantly lower than the increase in TPC by 66% if the pretreatment is done by water leaching only of the ground crop residues.

Comparative analysis of briquettes obtained from biomass and charcoal

It is well known that there is a need for large amount of energy from alternate fuels due to the depletion of fossil fuels and increased energy demand. This paper analyses the important properties of biomass, charcoal with and without binder as alternate fuels. Also, the effect of solid and hollow briquettes on ash, moisture contents and volatile matter of the briquettes are studied. The briquettes are made from wood waste and charcoal. Starch has been used as binder with charcoal. The calorific value, moisture content, ash content and volatile matter were estimated. The investigation shows that the pure charcoal possesses higher calorific value than that with binder and biomass. However the addition of binder can reduce ash content, moisture content and volatile matter which may lead to the benefits of reduced corrosion effect.

Hydrothermal co-carbonization of sewage sludge and high concentration phenolic wastewater for production of solid biofuel with increased calorific value

Hydrothermal carbonization has proven to be an effective method to convert sewage sludge into solid carbon-rich hydrochar, of which the high ash content is generally regarded as limiting factor for energy-related potential application. Hydrothermal co-carbonization of sewage sludge and high concentration phenolic wastewater was firstly investigated in this study as a scenario for production of clean solid biofuel with increased calorific value and decreased ash content, by means of polycondensation reactions between phenols and highly reactive intermediates of biopolymers in sewage sludge. Results showed that addition of phenolic wastewater into sewage sludge led to a substantial increase of hydrochar yield (1.83–31.11%) and higher heating value (1.01–10.01%) and a remarkable decrease of ash content (1.39–25.68%). The reaction temperature and residence time had a complicated impact on the contribution of phenol to hydrochar production. An increase in phenol mixing ratio was beneficial to the improvement of mass yield and higher heating value but showed a less influence on the reduction of ash content. The synergistic effects between phenols and sewage sludge on the production of solid biofuel were closely related to the phenolic species, which followed the order in the aspects of hydrochar yield increase and ash content decrease: phloroglucinol > p-nitrophenol > m-cresol > phenol. The changes of phenols content in liquid phase and variations of functional groups in hydrochars implied that phenols interacted with sewage sludge and incorporated into hydrochars during the hydrothermal co-carbonization. TG-DSC confirmed the improved combustion reactivity of the phenols-sludge-derived hydrochars.

DIFFERENCE IN THE CARCASS QUALITY AND MEAT CHEMICAL COMPOSITION IN TWO LINES OF SLOWGROWING CHICKENS WITH OR WITHOUT ACCESS TO PASTURE

The study was carried out to compare the carcass quality and the chemicalcomposition of breast and thigh meat in two lines of slow-growing male chickens -La Belle (LB) and Bresse Gauloise (BB) reared conventionally or outdoors, havingaccess to pasture. The birds were slaughtered at 12 weeks of age. Two-wayANOVA was used to assess the effect of the rearing strategies as well as the line onthe carcass quality and meat chemical composition. Rearing system affectedsignificantly the carcass traits of the birds. The lines reared on pasture had lowerlive and carcass weight as well as lower dressing percentage (P<0.001). On theother hand they had higher percent (P<0.001) of the edible by-products (neck andgiblets). The percentage of the breast meat was significantly reduced in the birdsthat had access to pasture (P<0.001), while thigh remained unaffected. Thepastured chickens displayed higher part of the wings (P<0.01). Outdoors rearinginfluenced the chemical composition in the breast and thigh meat of the lines.Chickens reared on pasture were characterised by lower lipid content (P<0.01) inbreast and reduced protein in thigh (P<0.05), as well as increased moisture in bothkinds of meat, however depending on the line (P<0.05). Furthermore, pastureaccess resulted in reduced ash content of the breast meat (P<0.001), which waslower in the LB chickens (P<0.01), while in thigh this parameter was stronglydetermined by the interaction of the rearing system and line of the birds (P<0.01).

Influence of physical and chemical compositions on the properties and energy use of lignocellulosic biomass pellets in Brazil

Lignocellulosic residues are potential sources of renewable energy, but these materials have low energy density and undesirable properties for energy use. For this reason, pelleting is a viable alternative for the biomass energy valorization because it produces high-energy-density solid biofuels. The aim of this research is to evaluate the physical, chemical, and energetic characteristics of pellets produced with lignocellulosic biomass blends (elephant grass [EG], eucalyptus wood [EW], and sugarcane bagasse [SB]) for bioenergy generation. For biomass and pellets, bulk and energy densities, chemical compositions, and heating values, were determined. For pellets, the mechanical durability, fines content, diametrical compression, diameter, length, and unit density were measured. Pellets presented increased heating value, bulk and energetic density, and reduced moisture content. The highest absolute ash contents were found in the compositions and pellets produced with high amounts of EG (2.89%–6.48%). The reduction of EG in the blends has improved the energy properties of pellets. A 55% reduction of ash content was observed in the pellets produced with 50% EG and 50% EW compared with the pellets produced with 100% EG. The pellets produced with biomass blends obtained better energy and mechanical performances when compared with those produced with only one biomass.

Preparation of low silicon ultra clean coal by flotation pretreatment followed by alkali-acid leaching combined process

ABSTRACT The alkali-acid combination leaching has the characteristics of reacting with most minerals from various grades coal and high safety but the removal of silicic minerals as quartz and aluminosilicate is very limited. To further remove quartz and aluminosilicate from coal, we optimized the samples size, alkali leaching concentration, temperature and contract times of leaching process, and designed a new demineralization process of flotation pretreatment followed by alkali-acid combination leaching. On leaching process the percentage demineralization was 86.81, but appending the flotation column pretreatment the percentage demineralization reached 94.51. To investigate the removal mechanism of quartz and aluminosilicate in coal, the mixture coal samples of quartz–coal and aluminosilicate–coal was carried out by combination leaching process. Leach samples characterization of raw coal, flotation pretreatment coal, and mixture coal were done by XRD, ICP-OES, and SEM-EDS analysis. The result of the analysis showed that production of quartz and aluminosilicate in alkali leaching tend to adsorb on the surface of coal, then these products form new impurities in acid leaching. Flotation removes part of the dissociated silicic minerals in advance, which reduces the adhesion of soluble silica-containing sodium salt produced by alkali leaching to the coal surface and thus leads to the reduction of ash content.

Lignocellulosic residue as bio-carrier for algal biofilm growth: Effects of carrier physicochemical proprieties and toxicity on algal biomass production and composition

Five types of lignocellulosic materials were applied as the bio-carriers for low-cost algal biofilm cultivation of three algal strains. The effects of bio-carrier physicochemical properties and toxicity on algal cells growth and attachment were investigated. Rougher and hydrophilic bio-carrier could yield more algal biomass than smoother and hydrophobic bio-carrier. Pine sawdust (diameter: 0.420–0.595 mm) performed the best when cultured Diplosphaera sp. (9.61 g·m−2·day−1) biofilm. Meanwhile, bio-carriers could be leached by the culture medium during cultivation, and their energy conversion proprieties could be improved due to the reduced ash contents and the decreased crystallinities. In addition, Chlorella vulgaris growth tests indicated that pine sawdust (15.45%) leachate promoted cell growth, whereas rick husk (15.48%) and sugarcane bagasse (13.19%) leachate inhibited cell growth. And bio-carriers leachates also modified the chemical compositions (lipid, protein and carbohydrate) of algal cells and increased the corresponding saturated fatty acids methyl ester content (from 48.71 to 55.58–57.08%).

Pretreatment of Coal by Acid Leaching As Feedstock Preparation For Co-Gasification With Biomass

Co-gasification process of coal and biomass is believed to be one of the promising way to produce hydrogen. The mixing of coal and biomass can solve the problems that usually happened during gasification of pure coal or pure biomass. Furthermore, the presence of synergistic effect between coal and biomass may increase the hydrogen production due to Alkali and Alkaline Earth Metal (AAEM) content in the biomass. However, the synergistic effect may be hindered by the presence of silica in the coal. The present study focuses on the reduction of silica content of coal by acid leaching. Based on the result, it is found that the use of hydrofluoric acid may significantly reduce the silica content shown by the reduction of ash content in the coal. Furthermore, acid leaching process also causes the increase of surface area of the coal which may increase the possibility of AAEM attachment to the surface and thus the gas production may increase as well.

Optimal processing of greenhouse crop residues to use as energy and CO2 sources

This work presents the development of suitable strategies focusing on greenhouse crop residues as energy and CO2 sources for improved food production in greenhouses. The utilization of greenhouse crop residues in combustion processes for heating and carbonic enrichment in greenhouses has previously been developed and evaluated. Nevertheless, greenhouse crop residues present several problems that make it difficult to use them for these purposes. Among the characteristics that can impede their use are excessive moisture and ash contents as well as their low density. In this work, the relevant solid fuel properties for this type of biomass have been studied.In addition, three pre-treatment strategies are proposed and evaluated, which aim to enhance the fuel quality of this biomass. These strategies were: 1) first relates to the drying strategy employed for reducing greenhouse crop residue moisture. 2) the second one relates to a reduction in ash content by avoiding contact with greenhouse soil and 3) mixing with other biomass kinds with better quality as solid fuels.The assays performed showed that these strategies were successful, resulting in biomass with a high heating value, up to 26.9 MJ/kg, and a lower ash content than untreated residues, with values as low as 13.0% dry weight. This value is closer to that for the standard biomass most commonly employed in direct combustion applications. The biomass produced has been verified as suitable for conventional boilers with thermal efficiencies up to 70%. The methods developed allow to reuse greenhouse crop residues as greenhouse fuel, providing both heat and CO2; thus enhancing production and sustainability.

Cost and profit impacts of modifying stover harvest operations to improve feedstock quality

AbstractBiomass quality attributes, and the potential tractability of those attributes, are key to a successful biomass feedstock supply chain, in addition to quantity and price. Modifying harvest operations is one potential approach to managing biomass feedstock quality for corn stover. For example, eliminating raking from stover harvest operations is proposed as an approach to reduce ash content. However, changes in the stover harvest configuration cause changes in per acre profits, per ton costs, and available supply at specified prices. Here we evaluate sensitivity of profit, cost, and supply to conversion from a three‐pass to a two‐pass stover harvesting configuration as a means to reduce ash content. For all simulated yields, harvest costs are $2–$3 per ton cheaper for three‐pass versus two‐pass systems wherever residue retention coefficients are less than 0.5, and per ton costs for both systems increase dramatically where residue retention coefficients are greater than 0.7. Per acre net returns are greater under all simulated yields wherever residue sustainability retention coefficients are less than 0.6. Under these conditions, farmers lose between $13 and $49 per acre by harvesting with a two‐pass rather than a three‐pass system. Where competing with stover markets with less stringent quality specifications, meeting ash targets by harvesting with a two‐pass system may require higher grower payments of the order of $9–$25 per ton to make up for the per acre lost revenue. When solving for the least‐cost supply, agronomic simulations suggest about 2/3 of stover is harvested with a three‐pass system. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd

Physicochemical Properties of Fuel Blends Composed of Heavy Fuel Oil and Tire-Derived Pyrolytic Oils

The paper presents physicochemical properties of pyrolysis oil (PO) blends obtained from pyrolysis of rubber and spent tires mixed with selected heavy fuel oil (HFO) and the effect of PO properties on physicochemical properties of the final heavy heating oil. On the basis of physicochemical properties determinations, one sample of PO was selected, which was characterized by the best properties from the point of view of technological application. In the next step, physicochemical properties for the selected sample of heavy heating fuel oil consisting of 25% PO and 75% HFO were determined. It was found that the most important property of tire-derived PO is the content of gasoline, i.e., light hydrocarbons with a boiling point below 180 °C, which determine the ignition temperature of the obtained fuel blends. This property determines also the amount of PO that can be added to HFO, on the order of 30 wt % and more. The lower content of light hydrocarbons, the greater the amount of PO can be used to compose HFO. A positive aspect of the use of tire derive PO for the composing of heavy heating fuel is about a threefold decrease in kinematic viscosity, lowering the flow temperature and a significant reduction in ash content. Other properties of the modified HFO remained virtually unchanged and the fuel obtained as a result of blending meets the requirements of the relevant standard.

Evaluation of combined screening and drying steps for the improvement of the fuel quality of forest residue wood chips—results from six case studies

Wood chip quality is essential for failure-free and low-emission combustion in automatically stoked small-scale biomass boilers (< 100 kW). Screening and drying of wood chips might be suitable to reduce fuel heterogeneity and to guarantee defined qualities according to ISO 17225-4. Six case studies on screening and drying of forest residue wood chips were performed at German biomass terminals. Screening was done using drum, star, or jigger screens. Drying was done in storage piles and in rolling bed, walking floor, belt, and batch container dryer. Throughput rate was assessed on-site. Fuel properties were analyzed according to international standards. Moisture content of fresh wood chips was too high for small-scale biomass boilers (up to 51 w-%). Raw materials did not comply with specifications of ISO 17225-4 (i.e., ash content, particle size) while fuel indices (Fe/Mn, Al/200) implied contamination with soil material. Technical drying provided moisture contents ≤ 15 w-% while natural drying in piles resulted in values often exceeding 35 w-%. Screening reduced ash content, fines, oversized particles, and the share of N, S, Cl, K, and Si. Screening of pre-dried fuels seems to be beneficial compared to screening of fresh wood chips. After processing, chips could usually be classified as specification A2 to B1 according to ISO 17225-4.

Screening of bacteria for coal beneficiation

Biobeneficiation is considered to be a clean coal technology as an alternative method to reduce sulfur and ash content present in coal by using microbes, in particular bacteria. Recent studies have demonstrated that bacteria can oxidize iron and reduced sulfur compounds present in coal because they promote the oxidative conversion of the reduced forms of sulfur to soluble, easily washed-out compounds. Moreover, the use of bacteria in coal beneficiation has the following advantages, such as simple operation, extensive installation, performed under the mild condition without harmful product, low energy consumption and eco-friendly method. Hence, this study dealt with the investigation of the bacteria capable of oxidizing iron and sulfur compounds and also reducing ash content present in coal. Nine bacteria isolated from mercury-contaminated gold mine sites in Bandung, West Java Province, Indonesia were screened for their ability to oxidize iron and sulfur compounds and reduce ash content. Of the nine bacteria studied, two bacteria (i.e., Pseudomonas plecoglossicida and Pseudomonas hibiscicola) were able to oxidize iron and sulfur compounds and reduce ash content at pH of ~4. The findings of this study provide evidence that both bacteria could be employed as an oxidizing agent that will be applicable for the beneficiation of coal.

Investigation of Organosolv Pretreatment to Natural Microbial-Degraded Empty Fruit Bunch for Sugar based Substrate Recovery

Abstract Fresh empty fruit bunch is highly susceptible to microbial attack when exposed to the natural environment for pro-long period. This natural microbial-degraded empty fruit bunch or DEFB was discovered to exhibit modestly higher cellulosic contents, reduced ash contents and modestly higher lignin content compared to fresh empty fruit bunch. Higher cellulosic contents extracted using lower pretreatment process severity after natural microbial degradation action had rendered DEFB a promising feedstock for lignocellulosic biofuel production. Pretreatment with 50 v/v% ethylene glycol in the presence of 3 v/v% NaOH performed the best result with 67.2% delignification and 90.6% alpha cellulose recovery. Pretreatment with 50 v/v% ethylene glycol in the presence of 5 v/v% H2SO4 and 5 v/v% FeCl3 were able to degrade alpha cellulose considerably. This information would be vital for the subsequent hydrolysis process to optimize the yield of reducing sugar from DEFB.

Deash and mercury rejection of fine coal in air dense fluidized bed with shallow bed height

Due to the serious environmental problem, dry coal separation has become the hot research topic in the world. In the study, an air dense fluidized bed was used for reduction of ash content and mercury rejection with shallow bed heights. The results showed that pressure drop fluctuation was smallest when bed height was 100 mm. When fluidized gas velocity was 1.50 Umf, the ash content decreased to 9.65, 10.33, and 11.74% for −6 + 3, −3 + 2, and −2 + 1 mm samples; the yield of clean coal were 77.45, 81.52, and 83.65% for −6 + 3, −3 + 2, and −2 + 1 mm samples; the mercury content decreased to 0.47, 0.48, and 0.48 ppm for −6 + 3, −3 + 2, and −2 + 1 mm samples. The results indicated that an air gas-solid fluidized bed has satisfied separation performance on fine coal beneficiation with shallow bed height.

Biomass densification: Effect of cow dung on the physicochemical properties of wheat straw and rice husk based biomass pellets

This study investigates the potential of cow dung, an animal manure, as a binder to enhance the physicochemical properties of the base pellet (a mixture of wheat straw and rice husk). In the first step, preliminary experiments were performed to select the best composition of wheat straw and rice husk for the base pellet. The selection was based on calorific value. Subsequently, the effect of operating parameters such as varying compositions of cow dung (0–100%), molasses concentration (0–100%) and drying time (12–48 h) was investigated. Thus, Central Composite Design using Response Surface Methodology was used to investigate the proximate analysis, calorific value, bulk density and durability of biomass pellets. The experimental results suggested that the addition of cow dung into the base pellet resulted in the increase of volatile matter, ash content, bulk density and durability of the base pellet. As a result, the maximum calorific value of 14.98 MJ/kg, moisture content of 3.37%, volatile matter of 45.49%, ash content of 31.38%, bulk density of 108990 kg/m3 and durability of 95% were obtained. However, optimization of operating parameters was performed to optimize the ash percentage. With the pellet composition of 8.5% (base pellet composition of 90% wheat straw and 10% rice husk), molasses concentration of 50% and drying time of 12 h, 52% reduction in ash content and 2.3% increase in calorific value were obtained at the cost of 38% reduction in the bulk density and insignificant reduction in durability of the produced pellet. Therefore, the use of waste material like cow dung as a binder can be considered as a sustainable approach to improve the physicochemical properties especially durability of biomass pellets. Thus, it can effectively be used to fulfill the energy and heating requirement of rural areas.

Hydrothermal Carbonization of Waste Babassu Coconut Biomass for Solid Fuel Production

Different waste biomasses have enormous potential for the production of solid fuel using carbonization techniques to many energy purposes. Synthesis of carbonaceous materials with different morphologies, porosity and chemical composition, using a simple and low-cost technique as hydrothermal carbonization has a huge potential to add value to the production chain of babassu, a regional palm. In this work, two important waste biomasses, derived from babassu coconut, called mesocarp and babassu kernel bran have been used as precursors to produce structured carbonaceous materials via hydrothermal carbonization. The produced hydrochars (HTCs) were characterized and their fuel properties were evaluated. The higher heating value (HHV) revealed values of up to 24.83 MJ/kg for hydrochar from mesocarp and up to 28.91 MJ/kg for hydrochar from babassu kernel bran, showing an increase of of 69 % and 89% of energy yield, respectively, in comparison with the respective precursor waste biomass. Furthermore, the energy density of hydrochars has increased with increasing treatment temperature. The chemical analysis have shown that fuel efficiency of mesocarp hydrochars has improved, such as reduction of ash content, volatile matter and oxygen amount as well as increment of total carbon and fixed carbon content. The evolution of biomass carbonization, as determined by FT-IR and Raman measurements, showed that most carbohydrates and proteins were decomposed at above 160 °C. The aromaticity of hydrochars increased with increasing temperature whereas considerable amounts of functional groups remained in the hydrochars after hydrothermal treatment. Due to enhancement of the fuel properties, these hydrochars can be used as efficient solid fuel in the regional context.

ЗАГРЯЗНЕНИЕ АТМОСФЕРЫ ПРИАНГАРЬЯ ВЫБРОСАМИ ТЭЦ-11 (Г. УСОЛЬЕ-СИБИРСКОЕ)

. The article deals with the problem of environmental pollution in the town of Usolye-Sibirskaya CHPP-11, which operates on the Zabituiskoye coal coals, which have an increased sulfur content (4,1%) and ash (23,0%). It is proposed to replace coal from the Zabituiskoye field with coal of the BZR grade of the Tulun section with reduced ash content, low sulfur content and good calorific value.