Low Sulfur Content Research Articles

Real-Time Electrical Conductivity Monitoring and Correlation with Sulfate Release and Acid Mine Drainage Potential from a Gold/Silver Paste Tailing Storage

Safe disposal of tailings as high-density thickened tailings or paste tailings can reduce the environmental risks of conventional tailings deposits, reduce water use, minimize tailings storage facility footprints, reduce the potential for acid mine drainage (AMD), and minimize risks of failure, among other advantages. In the dewatering process, the addition of flocculants is key to improving the sedimentation of the tailings and the formation of a compact paste. Despite the environmental and operational advantages of using paste tailings, it is not clear how the chemical nature of coagulants and flocculants could influence the discharge of toxic elements (salts and metals) from tailings after storage. In this study, we show the results of the real-time evaluation of the release of polluting runoffs from a paste tailings deposit. To do this, we analyzed paste tailing samples for AMD potential through static and kinetic tests and monitored the electrical conductivity and real-time pH, evaluating the correlation with the sulfate in the thickener and downstream from the tailings deposit. Tailing samples have low sulfur content (<2%) and low acid-generating potential. Moreover, there is no evidence of a significant positive correlation (Pearson’s coefficient r < 0.8) between the sulfate concentrations with the pH or EC. Thus, the chemical nature of the paste tailings prior to discharge has no direct impact on the release of sulfate-rich runoffs from the tailings after its storage. This indicates that the tailings paste at the evaluated site is chemically stable in the short term.

Production and characterization of metallurgical coke from duduguru coal

This work illustrates the production and characterization of metallurgical coke from Duduguru coal, Obi local Government Area of Nasarawa State, Nigeria. The analytical assessment of properties such as proximate analysis, elemental composition, and calorific value are very important to know the coking qualities of the coal. The proximate analysis showed that the moisture content, ash content, volatile matter, fixed carbon and calorific values of the coal are; 1.86%, 18.82%, 43.74%, 53.58% and 5405.15 Cal/g respectively. Based on the result of the proximate analysis, the coal is of good metallurgical coke quality from an industrial prospective and heat generation is to be considered. Elemental analysis shows that due to the low heavy metals, low sulfur content and ash content of the coal, utilization of the coal within a safe environment is feasible with just a little environment impact and make it suitable for blending with strong coking or caking properties. Â

Graphdiyne-like Porous Organic Framework as a Solid-Phase Sulfur Conversion Cathodic Host for Stable Li-S Batteries.

As a unique branch of Li-S batteries, solid-phase sulfur conversion polymer cathodes have shown superior stability with fast ion-transfer kinetics and high discharge capacities owing to the mere existence of short-chain sulfur species during charging/discharging. However, representative compounds such as sulfurized polyacrylonitrile (SPAN) and polyaniline (SPANI) suffer from low sulfur contents and poor cycling performances under large current densities due to the sulfurization occurring only on polymers' surface. Here, a graphdiyne-like porous organic framework, denoted as GPOF, is synthesized and used as a host for enabling solid-phase sulfur conversion. Plenty of unsaturated bonds in GPOF provide sufficient reaction sites to bind sulfur chains, resulting in a high active sulfur content in the cathode. Moreover, the microporous GPOF possesses suitable cavities to accommodate the volume expansion, leading to favorable long-term cycling stability. As a result, the sulfurized GPOF cathode (SGPOF-320) displays outstanding electrochemical stability with negligible capacity decline after 250 cycles at 0.2 C with an average discharge capacity of 925 mA h g-1. Our work applies a facile procedure to produce sulfur conversion porous polymer cathodes, which could provide a proper way for exploring more suitable cathode materials for high-performance Li-S batteries.

Economic and environmental analyses of biomass torrefaction for injection as pulverized material in blast furnaces

Biomass was the first material used as a fuel by humanity, being replaced by fossil fuels after the industrial revolution. With the growing of environment discursions and the effects of CO2 emissions, biomass has been gaining strength as a potential alternative to fossil fuels, especially for steelmaking, which is responsible for about 5 to 10% of all CO2 emitted. It is known that biomass, compared to fossil fossils, has a higher volatile content, high moisture and lower calorific value. On the other hand, it has a higher hydrogen content and lower sulfur content (important for the steel industry), in addition it is considered neutral in CO2 emissions. Torrefaction, heating biomass at a temperature between 200-280°C in an oxygen free atmosphere, is an interesting treatment to adapt biomasses for use in the steelmaking processes, mainly in the pulverized material injection into the blast furnace. PCI is an extremely important process for the production of iron in the blast furnace, due to its ability to reduce coke consumption and optimize the operation of the reactor. This article comes with the purpose of presenting a bibliographic review about PCI technique, torrefaction process, biomasses and its applicability in the steel industry. In addition, an economic and environmental analysis of the possible use of biomass in steelmaking processes will be presented. Results shows that the use of torrefied biomass in the injection process is interesting, generating savings of 10 dollars and reduction of 264kg in CO2 emissions per ton of hot metal, with a replacement of 50% of the coal used by biomass.

The influence of a magnet field on sulfur removal from liquid iron by hydrogen plasma arc melting

In this work, the static magnetic field was applied to plasma arc melting (PAM) method. The influence on sulfur removal from iron by Ar-20%H2(PAM) was investigated experimentally. The results show that, sulfur content decreases more noticeably with the magnet field. The mechanism of sulfur removal by hydrogen plasma arc melting (HPAM) was found to obey a first-order rate law. From kinetic analysis, the adoption of magnet field enhanced purification efficiency about 45% under the same conditions. The numerical simulations were necessarily carried out to investigate the fluid flows of the melt. The results show that the magnet field changes the flow regime and strengthens the flow velocity of the melt. Moreover, the dead zone in melt by typical HPAM was eliminated. It is reasonable that dissolved sulfur atoms transferring to the top interface to react with active hydrogen atoms was promoted. In addition, during solidification process, thermoelectric magnetic (TEM) flows promote solute atoms that discharged from the solid–liquid interface moving to the upside of specimen. As a consequence, iron with much lower sulfur content could be obtained at the bottom of specimens, and sulfur removal was enhanced further during solidification under a static magnetic field.

Distribution and enrichment of Al-Li-Ga-REEs in the High-Alumina coal of the Datong Coalfield, Shanxi Province, China

The content, distribution, and origin of aluminum, lithium, gallium, and rare earth elements (REEs) in the Permo-Carboniferous coal of the Datong coalfield, China, were investigated using optical microscopy and field-emission scanning electron microscopy in conjunction with energy-dispersive X-ray spectrometry, X-ray powder diffraction, and inductively coupled plasma mass spectrometry. The Permo-Carboniferous coal of the Datong coalfield had a high volatile bituminous rank (Ro,max = 0.72% on average), and low sulfur and medium ash contents (0.58% and 25.74% on average, respectively). The main minerals in the Datong coal included kaolinite, boehmite, muscovite, calcite, dolomite, siderite, aluminum phosphate, and quartz. Of these, kaolinite, boehmite, calcite, quartz, and phosphates mainly occurred as cell fillings, indicating an authigenic origin. Compared to hard coals worldwide, the Datong coal is enriched in SiO2 (49.12%; up to 89.93%), Al2O3 (38.88%; up to 71.37%), Li (67 μg/g; up to 354.1 μg/g), Ga (18.1 μg/g; up to 70.2 μg/g), Y (20.8 μg/g; up to 46.1 μg/g), La (34 μg/g; up to 158.5 μg/g), Ce (61.3 μg/g; up to 353.8 μg/g), Tb (0.7 μg/g; up to 3.0 μg/g), Er (2.3 μg/g; up to 5.7 μg/g), and Yb (2.2 μg/g; up to 5.4 μg/g). High-alumina coal (Al2O3 content in ash > 40%) occurred in the northern and southern parts of the coalfield. In the No. 3–5 coal seam, the areas of Li enrichment were located in the north and middle of the coalfield. In the Tashan and Chaigou mines, the Ga content exceeded 30 μg/g. An area of REEs enrichment (REEs content > 300 μg/g) was identified in the Tashan and Xiaoyu mines. In the No. 3–5 coal seam, the REEs distribution pattern showed a wide and gentle “V” curve with a high left and a low right limb. These seams were characterized by a marked depletion in Eu (δEu = 0.51) and a weak negative Ce anomaly (δCe = 0.95). In the No. 3–5 coal seam, Al, Li, Ga, and REEs mainly occurred in kaolinite. Boehmite and phosphate minerals were the main carriers of Ga and REEs, respectively. The enrichment in Al-Li-Ga-REEs in the No. 3–5 coal seam was mainly influenced by the sedimentary provenance and the environment of coal accumulation. The sediment sources were oxidized bauxite in the weathering crust of the Benxi Formation and the Middle Proterozoic moyite of the Yinshan Oldland to the north and west of the coalfield. Al, Li, Ga, and REEs were transported from the source region as solutes and colloids, and they became enriched in the swamp facies of the delta plain. The Li, Ga, and REEs contents gradually increased from the bottom to the top of the Permo-Carboniferous coal seam. This increase is mainly attributed to the weak influence of seawater. The marked enrichment in heavy REEs at the bottom of the No. 5 coal seam may be related to marine transgression.

Structure-related electrochemical behavior of sulfur-rich polymer cathode with solid-solid conversion in lithium-sulfur batteries

Severe shuttle effect of sulfur cathodes hinders commercial application of lithium-sulfur batteries. Current technologies for sulfur cathodes by physical confinement and chemical absorptions are not enough to solve the issues of the sulfur cathodes. Organosulfur cathodes with solid-solid conversions were proposed to fundamentally avoid shuttle effect. However, in previous reports, low sulfur content and complicated electrochemical process prevent application of organosulfur cathodes in lithium-sulfur batteries. Herein, we report new solid-solid conversion based on the organosulfur cathodes in ether-based electrolytes by developing sulfur-chain controlling strategy to obtain trisulfide polymers with high sulfur content over 76 wt%. Furthermore, reaction mechanism of sulfur-based cathodes is analyzed by constructing different sulfur chains based on the strategy. Theoretical calculations suggest polymers with disulfide bonds might exhibit new lithiation behavior, which is consistent with electrochemical results. This work demonstrates new electrochemical behavior of organosulfur cathode with solid-solid conversion and show promising application prospect of these polymers.

Comparative study on fuel characteristics and pyrolysis kinetics of corn residue-based hydrochar produced via microwave hydrothermal carbonization

Corn residues are an important source of bioenergy. Due to their highly diverse lignocellulosic structures, the hydrochar produced from microwave-assisted carbonization of different corn residues may have distinct fuel properties and pyrolysis kinetics. This study comprehensively investigated the effect of processing temperature on the basic fuel properties of hydrochar and examined the pyrolysis behavior of hydrochar as a precursor through kinetic analysis. The results indicate that the fuel quality of corn straw hydrochar prepared by microwave-assisted hydrothermal carbonization at 230 °C was significantly improved over that of its feedstock, with a higher heating value of approximately 20.7 MJ/kg. Hydrochar prepared by microwave-assisted hydrothermal carbonization of corn cob at 230 °C presents noticeable environmental advantages because it contains the lowest ash and nitrogen contents (0.5% and 0.5%, respectively) and lower sulfur content (0.05%). Moreover, regarding the kinetic modeling, the Doyle and Coats-Redfern models, which are both first-order and single-step kinetic models, were identified as satisfactory in interpreting the key pyrolysis kinetic parameters. Additionally, the microwave-assisted hydrothermal process increased the apparent activation energy of hydrochar due to the increase in crystallinity and the increase in the number of CC and CO bonds.

Analysis mixed characterization of Kalimantan coal and mangrove wood charcoal character as briquette raw material

This study using three types of coal from East Kalimantan and South Sulawesi Mangrove Wood Charcoal which consisted of various compositions. In sample analysis using analysis, namely: proximate, ultimate, and calorific value. Proximate analysis: ash content, volatile matter, moisture content, fixed carbon; ultimate analysis: carbon and sulfur content and the calorific value using the bomb calorimeter method. The results of the proximate analysis showed that the fixed carbon content was obtained in the mixture of MWC 75% + KJA 25% = 52.45%, while the lowest was obtained at IC 100% = 32.86%; The highest volatile matter was obtained at KJA 100% = 44.23%, the lowest was at MWC 75% + KJA 25% = 31.90%, the highest ash content was IC 100% = 9.14% the lowest was at MWC 75% + KJA 25% = 5.94% and the highest moisture content was seen at IC 100% = 15.17% but MWC 75% + IC 25% = 9.52%. The results of the ultimate analysis showed that the lowest sulfur content was in the mixed variation of MWC 75% + KJA 25% = 0.168%, while the highest sulfur content was obtained at IC 100% = 0.874%. However, it was still in the low sulfur category <1. The highest calorific value is obtained by varying the composition at MWC 75% + IC 25% = 5919 cal/gram, while the lowest was obtained at KJA 100% = 4913 cal/gram. So based on this research, the addition of mangrove charcoal is very good for increasing the calorific value.

I, N Co-doped hierarchical micro/mesoporous carbon modified separator for enhanced electrochemical performances of lithium-sulfur batteries

Although the high discharging capacity and coulombic efficiency can be obtained by impregnating sulfur into various conductive porous hosts in lithium-sulfur (Li-S) batteries, the low sulfur loading content and volumetric specific energy diminish their advantages. To solve this problem, a modified layer is prepared by coating I and N co-doped hierarchical micro/mesoporous kelp bio-carbon on surface of the polypropylene separator. Furthermore, the composite porous carbon is obtained by one-step thermal pyrolysis of edible dried kelp. The modified layer on separator can effectively prevent shuttle of polysulfides due to the synergistic effect from the micro/mesoporous carbon structures (physisorption effect) and I and N co-doped electrochemical active sites in carbon matrix (chemisorption effect), allowing high capacity and high coulombic efficiency. In this study, we developed Li-S batteries with 80% sulfur loading content and the area loading is higher than 2.0 mg cm−2, which are better than previous published ones. In addition, the cathode electrode could stabilize at 760 mAh g−1 after 200 cycles at 0.5 C and delivers a high retention specific capacity of 498 mAh g−1 after 500 cycles with a slight capacity attenuation of 0.07% per cycle.

Performance and poisoning analysis of organic sulfur resistance of Pd-Ce catalyst in catalytic oxidation of VOCs

In this paper, the effect of organic sulfur on the catalytic oxidation of toluene was explored. It was found that the low concentration of organic sulfur could cause rapid deactivation of the catalyst, and the activity of the catalyst could be restored to 100% after stopping the application of sulfur. The sulfation modification could significantly improve the organic sulfur resistance of the catalyst by changing the support and the sulfation modification of the support. There was a large amount of carbon deposition and a small amount of S-containing substances on the catalyst surface after the introduction of organic sulfur through the methods of TG, BET, FTIR, SEM (Mapping) and XPS. Then, through in-situ DRIFT and CH3SH-TPD, it was found that sulfation modification could inhibit the adsorption of organic sulfur on the catalyst surface and reduce the competitive adsorption. The decrease of catalyst efficiency due to the presence of organic sulfur in the reaction gas during VOCs catalytic oxidation is mainly due to the competitive adsorption of organic sulfur and VOCs molecules, and the temperature of VOCs catalytic oxidation of organic sulfur. Some polyhydrocarbons, ethyl sulfide, dimethyl sulfoxide and other substances were produced by incomplete oxidation, which covered the surface of the catalyst due to adsorption or deposition, resulting in catalyst poisoning.

The origins of paraffinic oils collected from oilfields in the western Siberian Basin, Russia: implications from geochemical and physical characteristics

Four oil samples were collected from oilfields in the western Siberian Basin, and analyzed using conventional geochemical and physical methods. The results of this study were used to evaluate the oil samples, focusing on the characteristics of their source rocks, including the origin of organic matter input; redox depositional conditions and degree of thermal maturity of their probable source rock were studied. The obtained SARA results show that the examined oils are paraffinic oils owing to their high saturated hydrocarbon fraction values of greater than 70% volume. The observed API gravity values (23.55° to 32.57°) and low sulfur content of less than 0.25% wt indicate that the examined oils are sweet oils and were generated from source rock containing Type-II, with low sulfur content. The low sulfur content combined with the vanadium (V) and nickel (Ni) ratios indicates that the examined oils were scoured from a mixture of aquatic and terrestrial organic matter, depositing under generally suboxic environmental conditions. The n-alkane and isoprenoid distributions, with their ratios and parameters further suggest that the examined oil samples were generated from source rock containing a mixed organic matter input and deposited under suboxic to relatively oxic environmental conditions. Bulk compositions and distributions of n-alkane and isoprenoid indicate that the oil samples were generated from mature source rock.

CONSERVATION, UTILIZATION OF LOCAL PLANT SPECIES, AND CULTIVATION AS THE EFFORTS OF CONTROLLING SALT AND SULFUR LEVELS AT THE BORDER OF BALURAN NATIONAL PARK, SITUBONDO REGENCY, EAST JAVA

The diversity of plant species functions as a shelterbelt, to prevent saltwater intrusion and avoid sulfur from the crater of Mount Ijen through the Banyuputih River in Situbondo Regency. The Situbondo-Banyuwangi area is strategic (Pantura), passing through the Baluran National Park, so it is essential to maintain biodiversity and water ecosystems. Mangroves, beach vegetation, cultivated plants, and forest vegetation are indicators of environmental protection and conservation. This study aims to reveal the diversity of flora species on the border of Baluran National Park, Banyuputih sub-district, Situbondo Regency, which is allegedly contaminated with salt material from the sea and sulfur from the crater of Mount Ijen. An interview was conducted to determine the function of flora, location elevation, water pH, and well depth. The results of the biodiversity survey were then collected and diagnosed, and the scientific name was then determined. Potential species diversity at the border from an altitude of 5 m above sea level (asl) – 62 m asl included 17 families and 29 species. The data on biodiversity, location elevation, water well depth, and pH indicate low sulfur and salt content; therefore, water resources can be used sustainably by the living things surround them.

Donor-π-Acceptor Heterosystem-Functionalized Porous Hollow Carbon Microsphere for High-Performance Li-S Cathode Materials with S up to 93 wt.

Lithium-sulfur (Li-S) batteries, as a prospective energy storage system, are still plagued by many problems that prevent them from their application, especially the low content of sulfur in the cathode. Herein, a cathode material with S up to 93 wt % is designed via a hollow donor-π-acceptor heterosystem, which combines catalytic sites, adsorption sites, and good conductivity together. Following this guidance, a hollow porous carbon sphere is prepared with CoO particles and single V atoms decorated on it (Co/V-HPCS), providing ultrahigh volumetric space for sulfur. Even the electrode made of sulfur-loaded Co/V-HPCS (Co/V-HPCS@S) has a high content of 90 wt % (sulfur content in the electrode is ∼83.5 wt %), and the cathode exhibits an excellent discharge capacity of 575.2 mAh g-1 under 0.2C after 100 cycles. With careful analysis by means of a high-resolution transmission electron microscope (HRTEM), the catalytic amounts of CoO particles and single V atoms loaded on the carbon shell are confirmed, which endows the material with outstanding catalytic ability to transfer sulfur and excellent adsorption of polysulfides. This concept of the cathode material increases the possibility of advanced long-life Li-S batteries with high tap density and high energy density.

Ni-based catalysts supported on acid/alkali-activated coal fly ash residue for improved glycerol steam reforming

Application of coal fly ash (FA) residues as catalyst support is mainly restricted because of low surface area and high sulfur content. In the present work, the physicochemical properties of a low-efficiency FA were significantly improved via simple acid/alkali treatments consisting of one-step (HNO3 or NaOH) or two-step (NaOH/HNO3 or HNO3/NaOH) leaching-partial-dissolution (LPD). As a result, as compared to Ni-FA, the catalytic activity of the Ni-FA(treated) catalysts for glycerol steam reforming was considerably enhanced. Alkali-LPD is more effective than acid-LPD in simultaneously improving FA’s surface area and regulating FA’s elemental distribution. Ni-FA(HNO3/NaOH) has the best performance with high glycerol conversion to gas (99.2%) and H2 yield (74.5%), attributed to i) removal of sulfur-containing species by acid-LPD, ii) upgrading specific surface area, iron-exposure, and Ni dispersion via alkali-LPD, iii) diminishment of coke using acid/alkali-LPD sequence treatment, and iv) enhancement of catalytic stability due to the formation of NiFe alloys.

Study on the Effect of Polysulfide Content on the Micromorphology and Spontaneous Combustion Characteristics of Coal

This paper aimed to study the effect of the polysulfide content on the micromorphology and spontaneous combustion characteristics of coal, in order to develop more targeted prevention and treatment strategies. To this end, this study selected the method of mixing different sulfides with very low sulfur content raw coal to prepare the coal samples to be tested. Various parameters, such as true density, porosity, micromorphology, and oxygen uptake of the different sulfur samples, were tested. The results reveal that sulfide had a certain expansion effect on the coal body and improved the pore structure of coal, and the porosity increased with the increase of the sulfur content. After adding iron (II) disulfide (FeS2) and iron (II) sulfide (FeS) powder to the original coal sample, the number of fine particles on the surface increased significantly. After increasing the oxidation temperature, the lamellar structure disintegrated, and the massive coal body was broken into several fine particles, which promoted the spontaneous combustion of coal. Polysulfide promotes the low-temperature oxygen absorption of coal and shortens the natural firing period of coal. FeS has a slightly greater effect on increasing the tendency of coal to spontaneously combust and shortening the shortest natural firing period of coal. Before the addition of FeS2 and FeS to the coal samples, the coal production amount was not much different below 80–90°C, and then, the gap gradually widened. Under the same temperature condition of coal, carbon monoxide (CO) production basically occurred first as the sulfur content increased. When FeS2 and FeS were added, the sulfur content of the coal samples was 3 and 4%, respectively, and the production of CO and ethene (C2H4) was the largest. Although the peak areas of aliphatic hydrocarbon, aromatic hydrocarbon, hydroxyl group, and carbonyl group in the coal samples with FeS were different, they all reached their maximum value when the sulfur content was 4%.

Valorization of fluid petroleum coke for efficient catalytic destruction of biomass gasification tar

Large volumes of waste petroleum coke stockpiled in open yard not only represent a huge loss of valuable material but also pose a significant risk to the environment. This work proposed an innovative strategy for waste petroleum coke valorization by exploring its catalytic performance of biomass gasification tar destruction. Waste petroleum coke was firstly activated by potassium hydroxide (KOH) to obtain high specific surface area as well as low sulfur and ash contents. Petroleum coke derived catalyst showed superior performance than a commercial activated carbon derived catalyst for destruction of naphthalene as the tar model compound. The petroleum coke derived catalyst exhibited 99.1% naphthalene destruction efficiency at 800 °C but deactivated quickly under N2 atmosphere. Under H2 and steam atmospheres, the catalytic activities were 98.6% and 96.5% for 8 h, respectively. To study the correlation between catalytic performance and the structure of carbon catalyst, elemental analysis, scanning electron microscope (SEM) analysis, transmission electron microscope (TEM) analysis, X-ray powder diffraction (XRD) analysis, Brunauer-Emmett-Teller method (BET) analysis, Fourier transform infrared (FTIR) spectroscopy, temperature programmed oxidation (TPO) analysis and Raman spectroscopy were performed on both fresh and spent catalysts. Results demonstrated that the hydrogen-rich groups (small rings and amorphous carbon) and oxygen-containing groups may account for the good resistance to coke deposition under H2 and steam atmospheres.

Modelling the co-firing of coal and biomass in a 10 kWth oxy-fuel fluidized bed

The oxy-fuel co-firing of solid fuels (such as coal, biomass, and solid waste) in fluidized beds is one of the most promising technologies for the industrial application of CO2 capture and waste disposal. However, both the practical experimentation and numerical simulations for elucidating co-firing in an oxy-fuel fluidized bed are still limited. In this study, a multiphase particle-in-cell scheme based on a 3D Eulerian–Lagrangian model was further developed following our previous research on oxy-fuel co-firing in a micro fluidized bed (Powder Technol. 2020, 373, 522–534). The refined JL 4-step mechanism for the CO-CO2 homogeneous reactions, the heterogeneous reactions of char oxidation and gasification, the heterogeneous reactions of NO and N2O formation from char-N, and the self-desulfurization effect were comprehensively considered. The improvement of the models was verified through the continuous operation of 10 kWth oxy-fuel fluidized bed tests (Fuel 2021,286,119,312; Energy Fuels, 2020, 34, 7373–7387), and the effects of the biomass blending ratio (Mb) on co-firing characteristics were discussed. It was found that the improvements could enhance the adaptability of the models to the oxy-fuel atmosphere, and the accurate prediction of NO, N2O, SO2. With an increase in Mb, the main reaction zone expanded or moved up along the riser height, and the volume of the high-temperature area increased, which promoted the burnout of particles and CO2 emission when Mb is 50%. The high volatility of biomass increased O2 consumption and CO concentration at the upper part of the riser, reduced N2O formation, and had a significant impact on NO reduction. The low sulfur content and high Ca/S ratio of the biomass considerably reduced the SO2 concentration. The simulation results also provided helpful information for the design and operation control of oxy-fuel co-firing of coal and biomass in a fluidized bed, such as the oxidant supply in different areas and grades, appropriate increase in the riser height, and reasonable adoption of Mb.

Effect of Injection Pressure on the Performance and Emission Characteristics of Niger-Diesel-Ethanol Blends in CI Engine

Biodiesel is promising as the best substitute/alternative fuel to most diesel engines due to its low sulfur content, lower aromatic hydrocarbon, renewable, and more oxygenated fuel. The dried Niger seeds were collected for their oil extraction and biodiesel production in the current research. This paper concerns about the influence of injection pressure on a single-cylinder VCR direct injection diesel engine using Niger oil biodiesel, diesel and ethanol blends, B5+D90+E5 (5% Biodiesel + 90% Diesel + 5% Ethanol), B10+D80+E10 (10% Biodiesel + 80% Diesel + 10% Ethanol) and B15+D70+E15 (15% Biodiesel + 70% Diesel + 15% Ethanol). The performance, combustion, and emission characteristics are observed for the above blends at the various pressures of 180 bar to 220 bar with 20 bar variations. At low injection pressures, the two blends (B5+D90+E5 and B10+D80+E10) show considerable improvement in brake thermal efficiency and mechanical efficiency compared to baseline diesel. At high injection, pressures blend B15+D70+E15 produce higher brake thermal efficiency and mechanical efficiency. Consequently, less brake-specific fuel consumption and less ignition delay period for the blends respectively. The exhaust pipe emissions such as Carbon Dioxide (CO2), Carbon Monoxide (CO), Hydrocarbons (HC), Nitrogen oxides (NOX) are measured at rated power at all injection pressures. CO2, CO, and HC are low at high injection pressure, but NOX increases as injection pressure increases.

Microwave co-pyrolysis for simultaneous disposal of environmentally hazardous hospital plastic waste, lignocellulosic, and triglyceride biowaste

Microwave co-pyrolysis was examined as an approach for simultaneous reduction and treatment of environmentally hazardous hospital plastic waste (HPW), lignocellulosic (palm kernel shell, PKS) and triglycerides (waste vegetable oil, WVO) biowaste as co-feedstock. The co-pyrolysis demonstrated faster heating rate (16–43 °C/min) compared to microwave pyrolysis of single feedstock (9–17 °C/min). Microwave co-pyrolysis of HPW/WVO performed at 1:1 ratio produced a higher yield (80.5 wt%) of hydrocarbon liquid fuel compared to HPW/PKS (78.2 wt%). The liquid oil possessed a low nitrogen content (< 4 wt%) and free of sulfur that could reduce the release of hazardous pollutants during its use as fuel in combustion. In particular, the liquid oil obtained from co-pyrolysis of HPW/WVO has low oxygenated compounds (< 16%) leading to reduction in generation of potentially hazardous sludge or problematic acidic tar during oil storage. Insignificant amount of benzene derivatives (< 1%) was also found in the liquid oil, indicating the desirable feature of this pyrolysis approach to suppress the formation of toxic polycyclic aromatic hydrocarbons (PAHs). Microwave co-pyrolysis of HPW/WVO improved the yield and properties of liquid oil for potential use as a cleaner fuel, whereas the liquid oil from co-pyrolysis of HPW/PKS is applicable in the synthesis of phenolic resin.