Co-pyrolysis Of Coal Research Articles

Influence of minerals and added calcium on the pyrolysis and co-pyrolysis of coal and biomass

AbstractThe pyrolysis behaviour was studied of two types of biomass (pine and wheat) and a Polish lignite (Turow) in the presence of minerals and ion-exchanged calcium using a variety of laboratory-scale methods including pyrolysis–gas chromatography–mass spectrometry (py–GC–MS) and thermogravimetric analysis coupled to a FTIR spectrometer (TGA–FTIR). Ion-exchange worked well for all samples, but particularly for the biomass, and the wt% Ca introduced followed the order wheat (4·17 wt%) > pine (1·74 wt%) > coal (0·80 wt%). The degree of catalysis displayed by the calcium during pyrolysis of the ion-exchanged samples varied with the fuel used. Significant catalysis by calcium was observed in pyrolysis of pine, but only a small effect was seen for wheat and very little for coal. The inherent minerals also play a catalytic role in all the samples studied, but potassium is by far the most important in the pyrolysis of the raw wheat straw. The gases and light volatiles are influenced by the presence of catalyt...

Improved solid fuels from co-pyrolysis of a high-sulphur content coal and different lignocellulosic wastes

Co-pyrolysis of blends of a high-sulphur coal with different biomass wastes has been investigated as a way to obtain improved solid fuels. Experiments have been performed in a thermogravimetric laboratory system and in a pilot-scale mobile bed furnace, this last operating at 600 °C. The presence of biomass enhances coal desulphurization upon thermal treatment in significant relative amounts, giving rise about as much as twice percent sulphur loss at high biomass-to-coal ratios in the starting blend in comparison with the S loss occurring upon pyrolysis of coal alone. Combustion experiments with chars resulting from co-pyrolysis of these coal–biomass blends confirm this significantly improved desulphurization. Thus, co-pyrolysis of blends of high-sulphur coals with biomass wastes provides a potential way to obtain improved solid fuels combining good heating values with environmentally acceptable S contents. The chars resulting from co-pyrolysis show heating values within the range of high-quality solid fuels whereas the ash contents remain in the vicinity of that of the starting coal except in the case of the coal–straw blend where the relatively high ash content of this biomass waste leads to co-pyrolysis chars with substantially higher ash contents and lower heating values.

04/00942 Thermal behaviour of coal/biomass blends during co-pyrolysis: Vuthaluru, H. B. Fuel Processing Technology, 2003, 85, (2–3), 141–155

Investigations into the thermalbehaviour during co-pyrolysis of coal, biomass materials and coal/biomassblends prepared at different ratios (10:90, 20:80, 30:70 and 50:50) have been conducted using a thermogravimetric analysis (TGA) apparatus. Coal sample selected was Collie subbituminous coal from Western Australia, while wood waste (WW) and wheat straw (WS) were used as biomass samples. Three thermal events were identified during the pyrolysis. The first two were dominated by the biomasspyrolysis, while the third was linked to the coalpyrolysis, which occurred at much higher temperatures. No interactions were seen between the coal and biomass during co-pyrolysis. The pyrolytic characteristics of the blends followed those of the parent fuels in an additive manner. Among the tested blends, 20:80 blends showed the lowest activation energies of 90.9 and 78.7 kJ mol-1 for coal/WW and coal/WS blends, respectively. It was also found that the optimum blend ratio for pyrolysis of coal/WS to be 50:50 with a high degradation rate in all thermal events and a higher mass loss over the course of the co-pyrolysis compared to coal/WW blends examined. The reaction orders in these experiments were found to be in the range of 0.21–1.60, thus having a significant effect on the overall reaction rate. Besides the pyrolysis of coal alone, the 50:50 coal/biomassblends had the highest reaction rate, ranging from 1×109 to 2×109 min-1.

04/00381 Co-pyrolysis of coal and woody biomass: Moghtaderi, B. et al. Preprints of Symposia — American Chemical Society, Division of Fuel Chemistry. 2003. 48. (1). 363–364

Introduction Fears of climate change and increasing concern over the global warming have prompted a search for new, cleaner methods of electrical power generation. Co-firing of biomass fuels (e.g. wood chips, straw, bagasse, peat and municipal solid waste) and coal is presently being considered as an effective means of reducing the global CO2 emissions. Demonstrations have been performed in a number of utility installations across the world, including Australia, Europe and the United States. All types of combustion technologies have been used but a particular attention has been given to pulverised fuel (PF) boilers, as they constitute the bulk of power generation hardware in many countries. Despite the simplicity of the co-firing concept, its application in PF boilers is associated with many technical issues including combustion related problems such as fuel ignition, flame stability, temperature, and geometry as well as char burnout. There is still no fundamental understanding of the underlying mechanisms that cause such technical problems. In particular, Studies on fundamental issues such as pyrolytic behaviour of biomass/coal blends or biomass char reactivity are scarce. Previous investigations on co-pyrolysis of biomass/coal mixtures have mostly concentrated on the mechanism of production of the gas phase species. There has also been a handful of studies on the impact of synergistic effects (i.e. chemical interaction between the two fuels) on the yield of major pyrolysis products, in particular, volatile matter. However, much less attention has been given to the influence of synergistic effects on the composition of the pyrolysis products. In addition, most previous studies focused on examining the impact of various controlling parameters (e.g. heating rate, temperature, blending ratio, etc) in isolation. The objective of this study was to address these shortcomings through a comprehensive investigation of the pyrolytic behaviour of woody biomass/coal blends over a wide range of heating rates and temperatures relevant to PF boilers. The fundamental knowledge gained from this project is essential for the proper understanding of co-firing in practical PF based systems. For example, the knowledge of the low heating rate pyrolysis of biomass/coal mixtures may help to prevent the accidental fires, which sometimes occur in fuel handling units (e.g. mills or pulverisers) of typical PF boilers during co-firing exercises. Similarly, the knowledge of the high heating rate pyrolysis of biomass/coal blends, may help to understand and predict the impact of co-firing on the combustion related phenomena in PF boilers.

Lithium insertion into boron containing carbons prepared by co-pyrolysis of coal–tar pitch and borane–pyridine complex

Carbon materials of boron content ranging from 0.6 to 4 wt.% were synthesized by co-pyrolysis of QI-free coal–tar pitch with the borane–pyridine complex. The growing amount of boron introduced into the carbonaceous material is associated with an increase in nitrogen content and a progressive degradation of structural and textural ordering. The structural variations of the boron-doped materials on heat treatment up to 2500 °C were monitored using X-ray diffraction and X-ray photoelectron spectroscopy. The intrinsic boron acts effectively as a catalyst of graphitization above 2100 °C. The carbonaceous material with boron content of about 1.5 wt% shows the highest degree of structural ordering after thermal treatment. A high amount of oxygen was found in the graphitized boronated carbons, proving that the incorporated boron induces a strong chemisorption activity of the material when exposed to air. For a series of cokes calcined at 1000 °C, the most striking effect of increasing the boron content is an increase of irreversible capacity X irr from 0.2 to 0.7. The reversible capacity ( X rev) amounts to about 1, with a slight tendency to decrease with the boron content. Upon increasing the temperature up to 2500 °C, X irr decreases to about 0.1 in the graphitic carbons, while X rev reaches a minimum of 0.4–0.5 at 1700 °C and next increases to a value close to 1 at 2500 °C. In the boron doped graphite, X irr has a slight tendency to increase with the boron content, due to the simultaneous presence of nitrogen in these materials and their strong affinity for oxygen from the atmosphere.

Low-temperature co-pyrolysis of a low-rank coal and biomass to prepare smokeless fuel briquettes

Smokeless fuel briquettes have been prepared with low-rank coal and biomass. These raw materials have been mixed in different ratios and have been pyrolysed at 600 °C with the aim to reduce both the volatile matter and the sulphur content, and to increase the high calorific value (HCV). The co-pyrolysis of coal and biomass has shown a synergetic effect. The biomass favours the release of hydrogen sulphide during the thermal treatment. This fact can be explained in terms of the hydrogen-donor character of the biomass. Moreover, the optimisation of the amount of binder and the influence of different types of biomass in the blend have been studied with respect to the mechanical properties of the briquettes (impact resistance, compression strength and abrasion). Briquettes prepared with sawdust (S) present better mechanical properties than those with olive stones (O) because of its fibrous texture.

RETRACTED: Investigations into the pyrolytic behaviour of coal/biomass blends using thermogravimetric analysis

Investigations into the pyrolytic behaviour during co-pyrolysis of coal, biomass materials and coal/biomass blends prepared at different ratios (10:90, 20:80, 30:70 and 50:50) have been conducted using a thermogravimetric analysis (TGA) apparatus. The coal sample selected was Collie sub-bituminous coal from Western Australia, while wood waste (WW) and wheat straw (WS) were used as biomass samples. Three thermal events were identified during the pyrolysis. The first two were dominated by the biomass pyrolysis, while the third was linked to the coal pyrolysis, which occurred at much higher temperatures. No interactions were seen between the coal and biomass during co-pyrolysis. The pyrolytic characteristics of the blends followed those of the parent fuels in an additive manner. Among the tested blends, 20:80 blends showed the lowest activation energies of 90.9 and 78.7 kJmol(-1) for coal/WW and coal/WS blends respectively. The optimum blend ratio for pyrolysis of coal/WS was 50:50 with a high degradation rate in all the thermal events and a higher mass loss over the course of the co-pyrolysis compared to coal/WW blends examined. The reaction orders in these experiments were in the range of 0.21-1.60, thus having a significant effect on the overall reaction rate. Besides the pyrolysis of coal alone, the 50:50 coal/biomass blends had the highest reaction rate, ranging 1x10(9)-2x10(9) min(-1). The experimental results may provide useful data for power generation industries for the development of co-firing options with biomass.

Kinetics of copyrolysis of coal with polyamide 6

Kinetics of thermal reactions of coal with polyamide 6 by TGA and DSC methods was studied and overall kinetic parameters were measured. In the range of about 350–500 °C the thermal degradation of coal proceeds, and gas and tar are evolved. Simultaneously, the thermal decomposition of polyamide 6 occurs and ε-caprolactam and other products are formed. The ε-caprolactam formation is promoted by water and hydrogen from coal degradation. Due to high content of hydrogen, coal acts as a strong H-donor. Because polyamide 6 is a significant component of waste polyamides mixtures and waste plastics, the thermal treatment of waste polyamides with coal was tested during copyrolysis in a stationary bed up to final temperature of 900 °C at the heating rate of 5 °C min −1. It was found that beside ε-caprolactam mainly carbon oxides, methane, aliphatic hydrocarbons, simple aromatics and stable oil are formed during copyrolysis. The yields of gas and tar/oil from copyrolysis with polyamides are higher in comparison with those from pyrolysis of coal alone.

Thermal behaviour of coal/biomass blends during co-pyrolysis

Investigations into the thermal behaviour during co-pyrolysis of coal, biomass materials and coal/biomass blends prepared at different ratios (10:90, 20:80, 30:70 and 50:50) have been conducted using a thermogravimetric analysis (TGA) apparatus. Coal sample selected was Collie subbituminous coal from Western Australia, while wood waste (WW) and wheat straw (WS) were used as biomass samples. Three thermal events were identified during the pyrolysis. The first two were dominated by the biomass pyrolysis, while the third was linked to the coal pyrolysis, which occurred at much higher temperatures. No interactions were seen between the coal and biomass during co-pyrolysis. The pyrolytic characteristics of the blends followed those of the parent fuels in an additive manner. Among the tested blends, 20:80 blends showed the lowest activation energies of 90.9 and 78.7 kJ mol −1 for coal/WW and coal/WS blends, respectively. It was also found that the optimum blend ratio for pyrolysis of coal/WS to be 50:50 with a high degradation rate in all thermal events and a higher mass loss over the course of the co-pyrolysis compared to coal/WW blends examined. The reaction orders in these experiments were found to be in the range of 0.21–1.60, thus having a significant effect on the overall reaction rate. Besides the pyrolysis of coal alone, the 50:50 coal/biomass blends had the highest reaction rate, ranging from 1×10 9 to 2×10 9 min −1.

Characterization of chars obtained from copyrolysis of coal and petroleum residues : Suelves, I. et al. Energy & Fuels, 2002, 16, (4), 878–886

Characterization of chars obtained from copyrolysis of coal and petroleum residues : Suelves, I. et al. Energy & Fuels, 2002, 16, (4), 878–886

Characterization of chars obtained from co-pyrolysis of coal and petroleum residues : Suelves, I. et al. Energy & Fuels, 2002, 16, (4), 878–886

Characterization of chars obtained from co-pyrolysis of coal and petroleum residues : Suelves, I. et al. Energy & Fuels, 2002, 16, (4), 878–886

Characterization of Chars Obtained from Co-pyrolysis of Coal and Petroleum Residues

Co-pyrolysis of coal and petroleum residue has been carried out in a bench scale unit in order to study the influence of the coal nature and the experimental conditions on the characteristics of the char obtained. Two coals of different rank, Samca (sub-bituminous) and Figaredo (bituminous), and a petroleum residue from the Maya crude have been used. Temperatures of 600, 650, and 700 °C, pressures of 0.1, 0.5, and 1 MPa, and mass ratios (Coal/PR) of 70/30 and 50/50 have been studied. A synergistic effect on char yields, which increases as temperature, pressure, and PR/coal ratio increase, is observed for both coals studied. Some relevant char characteristics of sulfur content, reactivity, and coking properties have been analyzed in order to determine a final use for the chars obtained. It is concluded that Samca/PR chars, especially for the 70/30 mixture, could be gasified to produce syn-gas. Coal /PR ratio higher than 50/50, temperature lower than 700 °C, and atmospheric pressure should be used in co-pyr...

Synergetic effects in the copyrolysis of coal and petroleum residues: influences of coal mineral matter and petroleum residue mass ratio

Synergetic effects in the copyrolysis of coal and petroleum residues: influences of coal mineral matter and petroleum residue mass ratio

Synergetic effects in the co-pyrolysis of samca coal and a model aliphatic compound studied by analytical pyrolysis

Pyrolysis is claimed as an alternative method to improve the quality of the products obtained from materials of a hydrocarbon nature such as coal and residues from petroleum distillation. Appearance of synergy in the production of light olefins and aromatic compounds during the co-pyrolysis of coal and petroleum residues has been previously stated. The aliphatic fraction of the petroleum residue (PR) previously studied, might play an important role in the occurrence of the synergy in coal/PR co-pyrolysis reactions. For that reason, different mixtures of Samca coal and a model aliphatic compound (C 50), have been co-pyrolysed at 900 °C and atmospheric pressure in a Pyroprobe 1000 CDS. Three different weight ratios coal/PR (70:30, 50:50, 40:60) were studied. Important synergetic effects were observed for the production of light olefins, specially ethylene, after the co-pyrolysis of the three mixtures, but the most intense effects appeared for the 50:50 one. Synergy in the evolution of small aromatic compounds was also observed when 70:30 mixtures were pyrolysed, but the synergy for these compounds disappeared when the ratio of pentacontane in the mixture was increased. These effects are similar to those observed when mixtures of Samca coal and PR were co-pyrolysed in the same experimental conditions, and so that, it can be concluded that the aliphatic fraction of PR is the one that leads the mechanism of the co-pyrolysis process.

Gas chromatographic study of the volatile products from co-pyrolysis of coal and polyethylene wastes

The aim of this study was to determine the volatile products distribution of co-processing of coal with two plastic wastes, low-density polyethylene from agriculture greenhouses and high-density polyethylene from domestic uses, in order to explain the observed decrease in coal fluidity caused by polyethylene waste addition. Polymeric materials, although they are not volatile themselves, may be analysed by gas chromatography through the use of pyrolysis experiments. In this way, a series of pyrolysis tests were performed at 400 and 500°C in a Gray-King oven with each of the two plastic wastes, one high-volatile bituminous coal and blends made up of coal and plastic waste (9:1, w/w, ratio). The pyrolysis temperatures, 400 and 500°C, were selected on the basis of the beginning and the end of the coal plastic stage. The organic products evolved from the oven were collected, dissolved in pyridine and analysed by capillary gas chromatography using a flame ionization detector. The analysis of the primary tars indicated that the amount of n-alkanes is always higher than that of n-alkenes and the formation of the alkenes is favoured by increasing the pyrolysis temperature. However, this effect may be influenced by the size of the hydrocarbon. Thus, the fraction C 17–C 31 showed a higher increase of n-alkenes/ n-alkanes ratio than other fractions. On the other hand, the difference between the experimental and estimated values from tars produced from single components was positive for n-alkanes and n-alkenes, indicating that co-pyrolysis of the two materials enhanced the chemical reactivity during pyrolysis and produced a higher conversion than that from individual components.

00/02782 Co-processing: co-pyrolysis of coal with organic wastes

00/02782 Co-processing: co-pyrolysis of coal with organic wastes

00/02786 Copyrolysis of coal and waste plastics under different reactivity gases

00/02786 Copyrolysis of coal and waste plastics under different reactivity gases

00/01804 Effect of operating conditions on copyrolysis of coal with waste plastics under coke-oven gas

00/01804 Effect of operating conditions on copyrolysis of coal with waste plastics under coke-oven gas

00/02088 Characteristics of three-product separation with an air-dense medium fluidized bed

Co-pyrolysis of coal and lignocellulose biomass and coal is the key step of other co-thermochemical conversion, and conversion of co-pyrolysis char is the rate-determining step of co-gasification and co-combustion. In this paper, the influence of biomass model compounds (cellulose, hemicellulose, and lignin, abbreviated as CE, HCE and LIG) on the co-pyrolysis char structure transformation was investigated. Carbon structure and surface morphology of co-pyrolysis char were examined by Raman spectroscopy and scanning electron microscope (SEM). A comprehensive comparison of Raman spectral deconvolution methods based on various fitting functions and peak numbers was explored, and Gaussian-Lorentzian-function with no less than nine peaks showed the best performance. Three biomass model show different effects on the transformation of microstructure structure. The addition of CE increased the ordering of char structure. HCE promoted the disordering degree of microstructure structure and reached the maximum at 50% HCE mass ratio. The microstructure structure changes of co-pyrolysis char for 25% and 50% LIG mass ratios were not evident, while 75% LIG increased the disordering degree of the co-pyrolysis char. Fractal analysis was applied for describing the char surface morphology quantitatively with two and three-dimensional fractal dimensions. CE decreased the fractal dimensions of co-pyrolysis, and the influence of HCE and LIG depended on the mass ratio.

00/02038 Co-processing: co-pyrolysis of coal with organic wastes

00/02038 Co-processing: co-pyrolysis of coal with organic wastes