Coprocessing Of Coal Research Articles

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.

00/03071 Two stage coprocessing of coal with model and commingled waste plastics mixtures

00/03071 Two stage coprocessing of coal with model and commingled waste plastics mixtures

00/01774 The direct liquefaction co-processing of coal, oil, plastics, MSW, and biomass

00/01774 The direct liquefaction co-processing of coal, oil, plastics, MSW, and biomass

Coprocessing of a Turkish lignite with a cellulosic waste material: 1. The effect of coprocessing on liquefaction yields at different reaction temperatures

In recent years, the liquefaction potential of waste materials has been investigated to increase the yield of coal conversion processes and the quality of liquid fuels from coal. The results have shown that the coprocessing of coal with biowaste materials increases liquefaction yields. In this study, the effects of liquefaction of Soma lignite with sawdust as a coprocessing agent, on total conversion, oil+gas total yields, asphaltene yields and preasphaltene yields were investigated at five different temperatures, 300, 325, 350, 375 and 400°C, 40 atm initial cold pressure, 1/1 (wt/wt) sawdust/lignite ratio and 3/1 (vol/wt) tetralin/(lignite+sawdust) ratio values.

00/00703 Coprocessing of coal and heavy oil—effect of properties of heavy oil on coal liquefaction behavior

00/00703 Coprocessing of coal and heavy oil—effect of properties of heavy oil on coal liquefaction behavior

00/00651 Synthetic pyrite-catalyzed coprocessing of coal and heavy oil vacuum residue using syngas-water as a hydrogen source

00/00651 Synthetic pyrite-catalyzed coprocessing of coal and heavy oil vacuum residue using syngas-water as a hydrogen source

99/04006 Interaction between raw materials during co-processing of coal with petroleum residue: Maxa D. et al. Pet. Coal, 1998, 40, (4), 224–227

99/04006 Interaction between raw materials during co-processing of coal with petroleum residue: Maxa D. et al. Pet. Coal, 1998, 40, (4), 224–227

Determination of Effective Conditions for Two-Stage Coprocessing of Coal with Waste Plastics and Petroleum Resid

Two-stage coprocessing of waste plastics with coal and petroleum resid was investigated using a one-third fractional factorial design. In the two-stage process, waste plastics were reacted in the first stage, and the liquid products from the first stage were then introduced into the second stage, which consisted of coal and petroleum resid. Four factors, each with three levels, were evaluated in the study, namely the catalyst type, the resid type, the plastic type, and the weight percent of coal. The catalysts were NiMo/Al2O3, NiMo/zeolite, and HZSM-5; the resids were Manji, Maya, and Hondo; the plastics were low-density polyethylene, mixed post-consumer, and mixed waste plastics collected in Germany; and the weight percents of coal were 0, 10, and 29%. The results from the factorial experiment were evaluated by determining their product distributions using solvent fractionation. The production of gas and hexane-soluble materials, as well as the conversion to THF-soluble materials, was measured. From the determination of the significance of each factor and factor interaction on the production of these products and the conversions obtained, the most effective conditions (i.e., the optimum factor level combination for the four factors) for performing two-stage coprocessing of coal, petroleum resid, and waste plastics using the factors studied were determined. The presence of coal, particularly at 29%, decreased the amount of conversion and production of hexane-soluble materials in the two-stage coprocessing reaction. By contrast, two-stage coprocessing of waste plastics and petroleum resid resulted in end products that were more conducive to further processing into chemical feedstocks and transportation fuels.

99/02958 Temperature programmed combustion studies of the co-processing of coal and waste materials

Highly parallelizable domain decomposition Dirichlet–Dirichlet solvers for hp-version finite element methods on angular quasiuniform triangular meshes are studied under different assumptions on a reference element. The edge coordinate functions of a reference element are allowed to be either nodal with special choices of nodes, or hierarchical polynomials of several types. These coordinate functions are defined within elements as being arbitrary or discrete quasi-harmonic coordinate functions. The latter are obtained from explicit and inexpensive prolongation operators. In all situations, we are able to suggest preconditioners which are spectrally equivalent to the global stiffness matrix, which only require element-by-element and edge-by-edge operations, and which reduce computational cost. In this way, elimination is avoided when dealing with the interface problem. The domain decomposition algorithms essentially use prolongation operators from the interface boundary inside the subdomains of the decomposition according to the approach initially used for the hp-version finite element methods with quadrilateral elements [S.A. Ivanov, V.G. Korneev, Izv. Vyssh. Uchebn. Zaved. 395 (1995) 62–81; Technische Universität Chemnitz–Zwickau, Preprint SPC 95-35, 1995, 1–15, and Preprint SPC 95-36, 1995, 1–14; Math. Modeling 8 (1996) 63–73].

Two stage coprocessing of coal with model and commingled waste plastics mixtures

Coprocessing of coal with waste plastics in two separate stages was investigated in order to tailor the reaction conditions and catalysts used in each stage for the materials present. In the first stage reaction, waste plastics were liquefied at 440°C (713 K) for 1 h with an initial H 2 pressure of 2.8 MPa and a catalyst, either the zeolite HZSM-5 or one of two cracking catalysts, Low Alumina or Super Nova-D, which was used to break selectively the hydrocarbon chains in the waste polymer. In the second stage, coal was added and the reaction conditions were selected to maximize the coal conversion and hydrotreatment of the dissolving coal molecules. The solvent used in the second stage was the hexane soluble fraction from the first stage reaction. Most of the second stage reactions were performed at 400°C (673 K) for 30 min, with an initial H 2 pressure of 5.6 MPa and a slurry-phase hydrotreating catalyst, either Mo naphthenate, Fe naphthenate, or a combination of the two, plus excess sulfur. Two types of waste plastics, a model mixture composed of 50% high density polyethylene (HDPE), 30% polyethylene terephthalate (PET), and 20% polystyrene (PS), and an actual mixture, composed primarily of HDPE and polypropylene (PP), were used. The catalysts chosen for the first stage reaction were found to have a significant effect on the quality of the hexane soluble liquids produced, and, hence, also affected the second stage processing. The second stage catalyst affected the overall product and boiling point distributions. Separation of the two reactions into two stages afforded the opportunity for selecting reaction conditions and catalysts to obtain a higher conversion and production of materials in the desired boiling point range than that available using single stage processing.

99/01805 Iron-catalyzed coprocessing of coals and vacuum residues using syngas-water as a hydrogen source: Hata, K.-a. et al. Energy Fuels, 1998, 12, (6), 1181–1190

99/01805 Iron-catalyzed coprocessing of coals and vacuum residues using syngas-water as a hydrogen source: Hata, K.-a. et al. Energy Fuels, 1998, 12, (6), 1181–1190

99/00927 Structural characteristics of Yanzhou coal and products in co-processing of coal and tar : Zou, G. and Ling, K. Meitan Zhuanhua, 1997, 20, (3), 79–83. (In Chinese)

99/00927 Structural characteristics of Yanzhou coal and products in co-processing of coal and tar : Zou, G. and Ling, K. Meitan Zhuanhua, 1997, 20, (3), 79–83. (In Chinese)

Coprocessing coal with hydrogenated vacuum pyrolyzed tire oil

GC–MS and NMR analyses of vacuum pyrolyzed tire oil (VPTO) show the presence of non-hydrogen donor polyaromatic molecules, such as naphthalene, anthracene, phenanthrene, pyrene, and their methylated derivatives. Thus, VPTO provides weak H-donor capacity. However, partial hydrogenations of VPTO converts the polyaromatics to hydropolyaromatic compounds, which are very good H-donor molecules. In this study, hydrogenation of VPTO was done using several types of presulfided hydrogenation catalysts, including Ni/Al 2O 3, CoMo/Al 2O 3, NiMo/Al 2O 3, NiW/Al 2O 3, Ni/SiO 2–Al 2O 3, Pd/carbon, unsulfided Pt/Al 2O 3 and Pt/carbon. Hydrogenation of VPTO was also investigated at different temperatures and hydrogenation pressures when the catalyst was Ni/Al 2O 3. The partially hydrogenated VPTO (HVPTO) products were then coprocessed with different coal ranks at several reaction temperatures and pressures with and without finely dispersed Mo naphthenate, Mo(CO) 6, (NH 4) 2MoS 4 and Mo/Fe 2O 3/SO 4 catalysts. The coprocessing of coal with several model compounds indicated that solvent effectiveness varies in the order of (non-donor polyaromatic model compounds)<(HVPTO)<(strong H-donor model compounds). No effect of varying coal rank is observed. NiMo/Al 2O 3 (6.7% of NiO and 27% MoO 3) and Ni/Al 2O 3 are the best catalysts for converting polyaromatics to hydrogen donor-rich hydroaromatics among nine tested catalysts. The best hydrogenation conditions are 325°C and 1000 psig of H 2 (cold). (NH 4) 2MoS 4 and Mo/Fe 2O 3/SO 4 are excellent coal liquefaction catalysts when HVPTO is coprocessed with coal.

Temperature programmed combustion studies of the co-processing of coal and waste materials

The disposal of waste materials using incineration methods is becoming increasingly important from the view point of the need to minimise the environmental impact of sewage sludge disposal. This investigation has involved the use of temperature programmed combustion (TPC) to study the interaction between coal, polyethylene, and dried sewage sludge which are possible components in coal/waste materials co-processing combustion systems. The TPC studies were carried out on the raw materials and 1:1 mixtures of sludge/coal and sludge/polyethylene. Comparison of the gas evolution profiles of the mixtures with corresponding profiles obtained by the summation of the profiles of the component materials indicate that there were interactions between the mixtures during the combustion. Significant interactions may occur when the combustion temperature ranges of the materials overlap.

Iron-Catalyzed Coprocessing of Coals and Vacuum Residues Using Syngas−Water as a Hydrogen Source

The effectiveness of alternative hydrogen sources compared to pressurized hydrogen gas toward the coprocessing of coals and vacuum residues was investigated in the presence of different kinds of iron-based catalyst precursors. The reactions in syngas−water using pentacarbonyliron or synthetic pyrite achieved high rates of conversion to THF solubles comparable to those in pressurized hydrogen gas, indicating the presence of the synergistic effects of the two hydrogen sources, hydrogen gas and carbon monoxide−water. Under hydrogen gas, addition of water greatly increased the yields of the desired fractions. The Fe(CO)5-catalyzed coprocessing of a vacuum residue of Arabian Heavy and Wandoan coal (2:1, 400 °C, 60 min, H2 3.0 MPa, CO 3.0 MPa, water 0.5 g) in combination with the pretreatment at lower temperature (200 °C, 30 min) afforded the high yields of THF-soluble (100%) and n-hexane-soluble (69.5%) matter. At higher reaction temperatures, 425−450 °C, the use of Fe(CO)5 with sulfur or synthetic pyrite afforded much better rates of conversion than Fe(CO)5 without sulfur. The XRD and XPS analyses revealed the formation of a mixture of magnetite and pyrrhotite from Fe(CO)5 without sulfur, and the surface of the used catalyst was mainly covered with iron species in a relatively high oxidation state. On the other hand, pyrrhotite was formed from Fe(CO)5 with sulfur or synthetic pyrite. The gas consumption, eventually the efficiency of the coprocessing, was estimated to be influenced by such changes in the state of the catalyst surface.

Evaluation of Synergy in Tire Rubber−Coal Coprocessing

The tire rubber−coal synergy is evaluated through the different roles that rubber can have in coprocessing systems. For that, two different experimental designs were used: a swept fixed-bed reactor and tubing bomb minireactors. In this way, coal was coprocessed with rubber liquids from rubber pyrolysis and rubber hydrogenation, in a hydrogen atmosphere at 400 °C. Coal was mixed as well with rubber in different proportions and hydrogenated at 375, 400, and 425 °C, and oils obtained were characterized by thin-layer chromatography to obtain hydrocarbon type composition. Rubber behavior was compared to each of the main components of tires, and all the results indicated that the slight synergy found can be due to the small free radicals from vulcanized rubber decomposition, which are able to stabilize coal radicals to light products.

98/02823 Liquefaction [hydrogasification] coprocessing of coal and natural gas by the Hynol Process: Steinberg, M. DGMK Tagungsber., 1997, 9704, (Proceedings ICCS '97, Volume 3), 1561–1564

We have found that adding a proper amount of water can dramatically improve conversion of a sub-bituminous coal in solvent-free liquefaction under at 350°C using ammonium tetrathiomolybdate (ATTM) as precursor to dispersed MoS2 catalyst H2 pressure. However, adding water to catalytic reactions at 400°C decreased coal conversion, although water addition to the non-catalytic runs was slightly beneficial at this temperature. We further examined the effect of water in solvent-mediated runs in addition to “dry” tests and explored a temperature-programmed liquefaction (TPL) procedure to take advantage of the synergetic effect between water and dispersed Mo catalyst precursor at low temperatures for more efficient coal conversion. The TPL using ATTM with added water at 350°C, followed by water removal and subsequent reaction at 400°C gave good coal conversion and oil yield. Model reactions of dinaphthyl ether (DNE) were also carried out to clarify the effect of water. Addition of water to ATTM substantially enhanced DNE conversion at 350°C. The combination of data from one-step and two-step tests of DNE and coal at 350–400°C revealed that water results in highly active MoS2 catalyst in situ generated at 350°C, but water does not promote the catalytic function or reaction once an active catalyst is generated. Using ATTM coupled with water addition and removal and temperature-programming may be an effective strategy for developing a better coal conversion process using dispersed catalysts.

ANOVA Analysis of Two-Stage Coprocessing of Low-Density Polyethylene, Coal, and Petroleum Resid

The sequencing of reactants and reaction parameters in the two-stage coprocessing of coal with low-density polyethylene (LDPE) and petroleum resid was investigated using two fractional factorial designs and analyses of variance (ANOVA). The experiments were designed to determine the sequence of reactants and the reaction conditions that were required to achieve the highest level of conversion of the solid reactants, and to achieve a desirable product slate in terms of product solubility and boiling point distribution. The reaction system that yielded the highest amount of hexane solubles regardless of the reaction temperature sequence or extraction after the first stage was the catalytic liquefaction of LDPE in the first stage, with the reaction products being added to coal and heavy resid in the second stage, which was also reacted catalytically. Examination of the effect of coal content and H2 pressure in the first and second stages showed that the H2 pressure affected the amount of coal conversion achi...

98/01144 Hydroprocessing of scrap automotive tires and coal. Analysis of oils from autoclave coprocessing: Anderson, L. L. et al. DGMK Tagungsber., 1997, 9704 (Proceedings ICCS '97, volume 3), 1549–1552

GC–MS and NMR analyses of vacuum pyrolyzed tire oil (VPTO) show the presence of non-hydrogen donor polyaromatic molecules, such as naphthalene, anthracene, phenanthrene, pyrene, and their methylated derivatives. Thus, VPTO provides weak H-donor capacity. However, partial hydrogenations of VPTO converts the polyaromatics to hydropolyaromatic compounds, which are very good H-donor molecules. In this study, hydrogenation of VPTO was done using several types of presulfided hydrogenation catalysts, including Ni/Al2O3, CoMo/Al2O3, NiMo/Al2O3, NiW/Al2O3, Ni/SiO2–Al2O3, Pd/carbon, unsulfided Pt/Al2O3 and Pt/carbon. Hydrogenation of VPTO was also investigated at different temperatures and hydrogenation pressures when the catalyst was Ni/Al2O3. The partially hydrogenated VPTO (HVPTO) products were then coprocessed with different coal ranks at several reaction temperatures and pressures with and without finely dispersed Mo naphthenate, Mo(CO)6, (NH4)2MoS4 and Mo/Fe2O3/SO4 catalysts. The coprocessing of coal with several model compounds indicated that solvent effectiveness varies in the order of (non-donor polyaromatic model compounds)<(HVPTO)<(strong H-donor model compounds). No effect of varying coal rank is observed. NiMo/Al2O3 (6.7% of NiO and 27% MoO3) and Ni/Al2O3 are the best catalysts for converting polyaromatics to hydrogen donor-rich hydroaromatics among nine tested catalysts. The best hydrogenation conditions are 325°C and 1000 psig of H2 (cold). (NH4)2MoS4 and Mo/Fe2O3/SO4 are excellent coal liquefaction catalysts when HVPTO is coprocessed with coal.

98/00283 Liquefaction [hydrogasification] coprocessing of coal and natural gas by the Hynol Process

98/00283 Liquefaction [hydrogasification] coprocessing of coal and natural gas by the Hynol Process