Solid Carbonaceous Material Research Articles

Solid carbonaceous materials transformation during pulverised coal and natural gas co-injection

Co-injection of coal and gaseous fuel, such as natural gas (NG), is common practice promoting pulverised coal gasification in blast furnace (BF) ironmaking. The high hydrogen content in NG makes it possible to act as cleaner reductant to reduce iron ore to produce hot metal, which will result in reduced CO2 emissions during the ironmaking process. In this work, selected parameters affecting the overall performance of the pulverised coal and natural gas co-injection system were studied using the CanmetENERGY injection test rig, including coal injection rate, natural gas rate and blast oxygen enrichment. Increase in combustion intensity promotes conversion of injected coal into solid carbonaceous material with relatively low reactivity with CO2. Hence, it reduces the competitiveness of combustion residues for oxygen in the raceway to continue the gasification process. NG co-injection reduces the coal combustion intensity but enhances the reactivity of combustion residues by competing the oxygen in the raceway.

Thermocatalytic decomposition of methane to low-carbon hydrogen using LaNi1-xCuxO3 perovskite catalysts

The thermocatalytic decomposition (TCD) of methane is an attractive alternative to produce low-carbon hydrogen and solid carbonaceous materials. In this study, substituted LaNi1-xCuxO3 perovskite catalysts prepared via self-combustion method were investigated for methane TCD. The effect of Ni partial substitution with Cu, varying gas hourly space velocity, temperature and stability on methane conversions were evaluated. PXRD, H2-TPR, SEM-EDS, TGA, and XPS were used to characterize the catalysts. An increase in Cu loading to 50%, increase in temperature and decrease in GHSV resulted in an improvement in methane conversions to 92%. At a GHSV of 2400 ml/gcat.h, no significant deactivation was observed as the stability of the LaNi0.5Cu0.5O3 catalyst increased from 6 to 20 hours’ TOS with methane conversions maintained at 92% where carbon nanofibers were observed on the surface of the spent catalysts. The study demonstrates the potential to prepare LaNi1-xCuxO3 catalysts and identify optimal testing conditions for the novel production of low-carbon hydrogen with minimal catalyst deactivation.

Study of two approaches for the process water management from hydrothermal carbonization of swine manure: Anaerobic treatment and nutrient recovery

Hydrothermal carbonization (HTC) is a promising alternative to transform biomass waste into a solid carbonaceous material (hydrochar) and a process water with potential for material and energy recovery. In this study, two alternatives for process water treatment by conventional and acid-assisted HTC of swine manure are discussed. Process water from conventional HTC at 180 °C showed high biodegradability (55% COD removal) and methane production (∼290 mL STP CH4 g−1 CODadded) and the treatment in an upflow anaerobic sludge blanket reactor allowed obtaining a high methane production yield (1.3 L CH4 L−1 d−1) and COD removal (∼70%). The analysis of the microbiota showed a high concentration of Synergistota and Firmicutes phyla, with high degradation of organic nitrogen-containing organic compounds. Acid-assisted HTC proved to be a viable option for nutrient recovery (migration of 83% of the P to the process water), which allowed obtaining a solid salt by chemical precipitation with Mg(OH)2 (NPK of 4/4/0.4) and MgCl2 (NPK 8/17/0.5), with a negligible content of heavy metals. The characteristics of the precipitated solid complied with the requirements of European Regulation (2019)/1009 for fertilizers and amendments in agricultural soils, being a suitable alternative for the recycling of nutrients from wastes.

Development of a Unique Technology for the Pyrolysis of Rice Husk Biochar for Promising Heavy Metal Remediation

Due to anthropogenic activities, potentially toxic elements cause severe soil pollution worldwide. Therefore, remediation of contaminated soils is exigent and imperative. One cost-effective and environmentally friendly remediation approach is the application of biochar, which is a solid carbonaceous material. Biochar degrades slowly in soil and can persist there for thousands of years, according to various estimations. In addition, coal obtained from crop wastes has a developed porous structure, a high specific surface area, and does not contain toxic compounds such as heavy metals and polycyclic aromatic hydrocarbons. Biochar with optimal values for specific surface area and porosity was obtained from rice husk by stepwise pyrolysis. The pyrolysis parameters such as the heating rate (11 °C∙min−1), temperature (700 °C), and holding time (45 min) were established. At the same time, the surface area of the biochar increased by almost three times with a change in the pyrolysis conditions. As a part of this research, the efficacy of adsorption of Cu(II) from Haplic Chernozem using biochar made from rice husk was examined. The Langmuir and Freundlich models were employed to describe the adsorption data. The isotherm data of heavy metals was better fitted to the Langmuir adsorption model. The addition of rice husk biochar to the soil presented greater removal efficiencies of Cu(II) than soil in pure form. The analysis of the structural characteristics of the sorbent suggest that this material may work efficiently for the restoration of contaminated soil.

Reduction of FeO in Molten Slag by Solid Carbonaceous Materials for HIsarna Alternative Ironmaking Process

To investigate the use of biomass in the novel HIsarna technology, the reduction of FeO in the slag by chars produced from thermal coal (TC), charcoal (CC), and Bana grass char (BGC) was studied. A drop tube furnace coupled with a quadrupole mass spectrometer (DTF-QMS) was employed to study the injection of chars into pre-melted slag in the temperature range between 1450 °C and 1525 °C. The reduction rate was calculated from evolved gases and the extent of FeO reduction was confirmed by wavelength-dispersive X-ray fluorescence (WDXRF). The FeO reduction proceeds through two stages, starting with a rapid reduction, which is dependent on the carbon type, and followed by gradual leveling off. The reduction rate with the charcoal char (CC) was the highest, over 60 pct reduction was achieved in the first 500 seconds at 1500 °C, while ~ 50 and 40 pct achieved with TC and BGC chars, respectively, for the same reaction time. The kinetic analysis suggests that the first and second stages of the reaction can be described by the second-order (F2) and three-dimensional diffusion (D3) models, respectively. The apparent activation energy values for the first stage were 290, 229 and 267 kJ/mol for reactions with TC, CC and BGC chars, while 265, 369, and 282 kJ/mol were obtained for the second stage. Based on the experimental data and kinetic results, it can be concluded that the first stage is controlled by chemical reactions on the carbon surface, and the second stage is influenced by a mixed-controlling mechanism.

Combustion kinetics of hydrochar from cow-manure digestate via thermogravimetric analysis and peak deconvolution

Hydrothermal carbonization (HTC) can convert wet biomass into hydrochar (HC), a solid carbonaceous material exploitable as fuel. In this study, HTC was applied to anaerobic digestate from cow manure. HCs obtained at three HTC temperatures (180, 220, 250 °C) were characterized in detail and their combustion behavior was investigated by thermogravimetric analysis (TGA) coupled with peak deconvolution. Increasing HTC temperatures increased the fixed carbon content (17.9–20.7%), the ash content (27.2–32.5%) and the calorific value (14.3–18.2 MJ/kg), while decreased the hydrogen (5.01–4.54%) and oxygen content (24.09–12.35%) of HCs. DTG profiles peak deconvolution unveils the presence of five major components in the HCs. HCs combustion kinetics were studied applying the KAS method. Average apparent activation energy values of 100, 88, 67 kJ mol−1 were obtained for HC180, HC220, HC250, respectively. HTC at 250 °C produced the HC with the best fuel characteristics.

Efficiency of using solid lump carbonaceous materials to increase heat capacity of converter process

Efficiency of using solid lump carbonaceous materials to increase heat capacity of converter process

Biochar-based cement pastes and mortars with enhanced mechanical properties

Nowadays, the environmental impact of cementitious material industry and more generally of building activities is matter of concern, especially in terms of their effects on climate change and consumption of natural resources. Within this context, the aim of this paper is the investigation of the role of biochar, a solid carbonaceous by-product material resulting from biomass pyrolysis/gasification of residual biomass, as a sustainable ingredient for the production of cementitious materials, combining carbon sink properties with enhanced mechanical properties. Although biochar is mainly investigated as agricultural amendment, there is also evidence that biochar may be a eco-friendly material to enhance the sustainable performance of cementitious materials. As outlined in literature, biochar can be used as filler to modify the nanogranular nature of cement matrix, or as substitute of clinker to reduce the emissions of greenhouse gases related to cement production. In this work, biochar is added as micro-nano particles in different cementitious composites, i.e. cement pastes and mortars, as a function of filler or partial substitute of cement. The main mechanical properties of biochar-based materials are then investigated to determine the optimal percentage of biochar addition.

Investigations on charcoal as fuel for a refillable scandia-stabilised zirconia electrolyte-based tubular carbon fuel cell

A carbon fuel cell (CFC) is an emerging technology for conversion of solid carbonaceous material into electricity at high theoretical efficiencies (100 %). As carbonaceous material like coal will remain an important energy source for the next few decades, the development of technology that can use it more efficiently is critical to reduce emissions. For practical operation of a CFC, a continual supply or consecutive refuelling of solid carbon fuel is required. Here, we investigated the electrochemical performance and durability of a CFC using a scandia-zirconia tubular electrolyte with Ce0.9Gd0.1O2–Ag electrodes with activated charcoal fuel. We demonstrated that CFCs can be operated in a batch-type process with refuelling and utilisation of fuel. Peak power densities up to 280 mW cm−2 were obtained without major materials degradation. We expect that advances to engineering of fuel delivery will improve the long-term stability and performance of the cells.

ТЕХНОГЕННІ ВУГЛЕВМІСНІ ОБ’ЄКТИ ЧЕРВОНОГРАДСЬКОГО ГІРНИЧОПРОМИСЛОВОГО РАЙОНУ ТА ДЕЯКІ ТЕХНІЧНІ РІШЕННЯ ЇХНЬОГО ВИКОРИСТАННЯ

Ukraine has significant coal resources. Chervonohrad Mining and Industrial District is the main coal complex in the west of Ukraine. In recent years, the average annual coal production in the mines of Chervonohrad Mining and Industrial District has amounted to 1.5 bn t, coal ash varies over a wide range of 25 to 53 %, average coal ash content of about 40 %. Coal mining has produced millions of tons of coal waste every year. Concentration of technogeneous coal objects (mines, mining infrastructure, coal-mining waste dumps and wastes of coal enrichment) in a relatively small area has caused environmental degradation. Therefore, technological and environmental aspects of carbon-containing technogenic objects are particularly important and actual. Coal-waste dumps in the territory of Chervonohrad Mining and Industrial District are characterized in detail. The dumps cover different areas – from 9–10 to 29–30 ha, the height of the dumps reaches 62 m at the mostly heights of 25–40 m. The total waste deposit in the dumps of existing mines has a volume of more than 20 million m3. The coal wastes from Mezhyrichanskaya mine coal-waste dump was investigated to determine the suitability for thermochemical processing. Technical characteristics of taken coal-waster samples is presented. The technogenic carbonaceous objects and the impact to the environment are evaluated. The developed and patented technical and technological solutions for the technogenic carbonaceous objects using are considered. It is shown that the concept of industrial development of coal wastes dumps is based on two aspects – extraction of valuable mineral components and energy utilization of carbonaceous wastes of coal production. Its patented as Patents of Ukraine technological schemes for terrestrial process in of solid carbonaceous raw material from dumps and sludges with the production of coal tar and synthesis gas CO + H2 are presented, as well as the scheme of a system for utilization of heat from coal dump. Recommendations for the implementation of innovative technologies are based on the results of the laboratory research. The purpose of the resolution is to obtain valuable components and energy from coal wasters while improving the environment.

Electrochemical reduction of nitric oxide in different carbon-driven solid state cells

A novelty of nitric oxide (NO) abatement technology in a solid state cell has been developed firstly, in which solid carbonaceous materials instead of gas (eg., H2 or CH4 etc.) work as reductant and fuel. The configuration of anode-supported nickel-yttrial stablized zirconia (Ni-YSZ), YSZ (yttrial stablized zirconia) electrolyte, LSM-YSZ (lanthanum strontium manganite-yttrial stablized zirconia) cathode, was fabricated into tubular cell with 13 mm in length and inner diameters 5 mm. Three carbonaceous materials, including activated carbon (AC), carbon black (BC) and graphite (GC), were investigated with regard to specific area, functional group, thermal activity and morphology by means of N2-BET, FT-IR, TG and SEM, respectively. NO conversion efficiency in excess of 85% can be achieved in the solid state cells driven by AC at 800 °C, higher than cells by BC and GC. BC is one of cheaper carbonaceous material substituting for AC in NO electrochemical reduction, due to its comparable performance. Higher specific area (1745 m2 g−1) and higher content of oxygen-containing functional groups assigned to AC contributes to the better electrochemical behaviours evidenced by AC impedance spectra. Similar thermal activities can be observed both for AC and BC. This novel configuration offers a low-risk, inexpensive and highly-efficient option applicable to purification of exhausts from diesel or gasoline engine.

Room temperature CO2 reduction to solid carbon species on liquid metals featuring atomically thin ceria interfaces

Negative carbon emission technologies are critical for ensuring a future stable climate. However, the gaseous state of CO2 does render the indefinite storage of this greenhouse gas challenging. Herein, we created a liquid metal electrocatalyst that contains metallic elemental cerium nanoparticles, which facilitates the electrochemical reduction of CO2 to layered solid carbonaceous species, at a low onset potential of −310 mV vs CO2/C. We exploited the formation of a cerium oxide catalyst at the liquid metal/electrolyte interface, which together with cerium nanoparticles, promoted the room temperature reduction of CO2. Due to the inhibition of van der Waals adhesion at the liquid interface, the electrode was remarkably resistant to deactivation via coking caused by solid carbonaceous species. The as-produced solid carbonaceous materials could be utilised for the fabrication of high-performance capacitor electrodes. Overall, this liquid metal enabled electrocatalytic process at room temperature may result in a viable negative emission technology.

High yields of solid carbonaceous materials from biomass

A method was developed for the production of carbon materials from biomass with high yields/strength via cross-polymerizing bio-oil, furfural and biochar.

High temperature pyrolysis of lignite and synthetic carbons

The paper explores changes in reactivity and chemico-physical characteristics of char and tar produced by severe heat treatment of lignite in both inert atmospheres and CO2 rich atmospheres. The role of mineral matter, in particular metal oxides, in catalysing chemical and physical transformations is also addressed. A Rhenish Lignite from the Garzweiler mine was studied and compared with: a) mineral-free synthetic carbon (HTC), obtained from cellulose; b) a synthetic carbon doped with iron oxide (Fe2O3). A heated strip reactor (HSR) was employed at temperatures of 1300 and 1800 °C in N2 and CO2 atmospheres. Liquid and solid products (tar and char) were analysed and compared. Tar composition was evaluated by extraction and gas chromatography-mass spectrometry, whereas the solid carbonaceous material produced by pyrolysis, mainly composed of char, was characterized regarding its thermal behaviour by thermogravimetric analysis and its structure by Raman spectroscopy and scanning electron microscopy. Results show that iron oxide exerts a catalytic influence on both pyrolysis and char oxidation. Upon severe heat treatment, it reduces char reactivity promoting graphitization and structural ordering. The overall effect on char reactivity is therefore not easy to predict.

Mechanical impregnation of Pd-Sn/alumina and Cu-Mn/graphite on charcoal to minimise carbon monoxide emissions

This study investigated how to minimize carbon monoxide (CO) emissions from charcoal by impregnating with Pd-Sn/alumina and Cu-Mn/graphite. Samples were heated isothermally with continuous monitoring of residual CO using electrochemical and infra-red sensors. With 0.2 wt% Pd-Sn/alumina, 26.9% and 44.4% were recorded as lowest and highest residual CO. On the other hand, when 2 wt% Cu-Mn/graphite was used, 15.6%, and 25.3% were observed as lowest and highest residual CO. The activity of the catalysts decreased with temperature and increased with catalyst loading. This method could be used on briquettes, wood boiler chips and other solid carbonaceous materials to minimise CO emissions.

Spatial distribution of carbon dust in the early solar nebula and the carbon content of planetesimals

A high fraction of carbon bound in solid carbonaceous material is observed to exist in bodies formed in the cold outskirts of the solar nebula, while bodies in the terrestrial planets region contain nearly none. We study the fate of the carbonaceous material during the spiral-in of matter as the sun accretes matter from the solar nebula. From observational data on the composition of the dust component in comets and interplanetary dust particles, and from data on pyrolysis experiments, we construct a model for the composition of the pristine carbonaceous material in the outer parts of the solar nebula. We study the pyrolysis of the refractory and volatile organic component and the concomitant release of high-molecular-weight hydrocarbons under quiescent conditions of disk evolution where matter migrates inwards. We also study the decomposition and oxidation of the carbonaceous material during violent flash heating events, which are thought to be responsible for the formation of chondrules. It is found that the complex hydrocarbon components are removed from the solid disk matter at temperatures between 250 and 400 K, while the amorphous carbon component survives up to 1200 K. Without efficient carbon destruction during flash-heating associated with chondrule formation the carbon abundance of terrestrial planets, except for Mercury, would be not as low as it is found in cosmochemical studies. Chondrule formation seems to be a process that is crucial for the carbon-poor composition of the material of terrestrial planets.

Characteristics of Soot from Rapid Pyrolysis of Coal and Petroleum Coke

Rapid pyrolysis of several types of solid carbonaceous materials [lignite, bituminous coal, and petroleum coke (petcoke)] was conducted in a drop-tube furnace at 1300 °C under atmospheric pressure. Soot properties, including yield, particle size, microstructure, and reactivity, were studied, with focus on the key factors that influence soot gasification reactivity. Results show that the soot yield of bituminous coal is up to 15–20 wt %, which is nearly half of the volatile matter, while those of lignite and petcokes are merely several percentages of the raw material. The reactivity of soot is lower than that of coal char and higher than that of petcoke char. Among several soots, lignite soot is most active, while petcoke soot displays the lowest reactivity. The catalytic effect of the mineral content is excluded because no alkali metal and alkaline earth metal were detected in soot samples. The reactivity difference is independent of the particle size but closely related to the microstructure. The soot pa...

Reactivity and Structural Changes of Coal during Its Combustion in a Low-Oxygen Environment

The aim of this study is to improve the understanding of phenomena that occur when a solid carbonaceous material is burned in a high temperature with a low-oxygen-content (<10%, v/v) environment similar to that found in the moderate and intense low-oxygen dilution (MILD) combustion. The morphology, reactivity, and physicochemical properties of partially reacted coal samples extracted from an environment emulating MILD combustion conditions were investigated through different analytical techniques, including elemental and thermogravimetric analyses, scanning electron microscopy, surface area, and Raman spectroscopy. The early stage of coal burnout was characterized by some changes in the organic constituents of coal because the low-molecular-weight compounds react quickly and are the first to be removed. After the devolatilization process under low oxygen combustion, an increase in surface area and porosity was observed simultaneously with a reduction in carbonaceous material reactivity as a result of the ...

High-molecular-weight organic matter in the particles of comet 67P/Churyumov-Gerasimenko.

The presence of solid carbonaceous matter in cometary dust was established by the detection of elements such as carbon, hydrogen, oxygen and nitrogen in particles from comet 1P/Halley. Such matter is generally thought to have originated in the interstellar medium, but it might have formed in the solar nebula-the cloud of gas and dust that was left over after the Sun formed. This solid carbonaceous material cannot be observed from Earth, so it has eluded unambiguous characterization. Many gaseous organic molecules, however, have been observed; they come mostly from the sublimation of ices at the surface or in the subsurface of cometary nuclei. These ices could have been formed from material inherited from the interstellar medium that suffered little processing in the solar nebula. Here we report the in situ detection of solid organic matter in the dust particles emitted by comet 67P/Churyumov-Gerasimenko; the carbon in this organic material is bound in very large macromolecular compounds, analogous to the insoluble organic matter found in the carbonaceous chondrite meteorites. The organic matter in meteorites might have formed in the interstellar medium and/or the solar nebula, but was almost certainly modified in the meteorites' parent bodies. We conclude that the observed cometary carbonaceous solid matter could have the same origin as the meteoritic insoluble organic matter, but suffered less modification before and/or after being incorporated into the comet.

Carbon type differentiation technique for diagnosing pulverised coal injection efficiency

Coal injection is a common practice for coke replacement in current blast furnace (BF) operations. The amount of coal that can be injected and successfully replace large coke is determined by the extent of coal gasification, which is a function of both the combustion environment in the tuyere/raceway region and combustibility of the injected coal. A new carbon type differentiation (CTD) technique was developed at CanmetENERGY for quantifying the amount of unburnt pulverised coal injection (PCI) residue that is carried in the furnace top gas for diagnosing the extent of injected coal gasification. This technique utilises the combustion characteristics of solid carbonaceous material generated during rapid pyrolysis and partial combustion of coal. The CTD technique developed was transferred to ArcelorMittal Dofasco and successfully implemented in the industrial environment. Using this technique, AM Dofasco established a PCI efficiency baseline for each of its three BFs, which will be used as a reference point for comparison in future trials. The capability of the CTD technique in diagnosing and understanding the effect of BF operating parameters on PCI burnout efficiency was demonstrated upon examining the effect of blast temperature decrease during a recent BF stove repair.