Gieseler Plastometer Research Articles

Relationship between coking properties measured by automatic Sapozhnikov plastometer with other measurements

ABSTRACT A Sapozhnikov plastometer is equipment that is commonly used, particularly in Asia, for measuring the contraction of the coal bed as well as the plastic layer thickness during the coking process. The relationship between the Sapozhnikov contraction X and the maximum plastic layer thickness Y values and other thermal rheology testing techniques is not fully understood. It leads to difficulties in the interpretation of data using different thermal rheology properties measurement techniques. In this work, a series of coal samples were analyzed in parallel using the automatic Sapozhnikov plastometer, the Gieseler plastometer, and the Ruhr dilatometer. The measurement results were compared to assist in the interpretation of data generated using different coal thermal rheology property measurement techniques. The Sapozhnikov X results are found not comparable due to the difference in sample particle size and testing conditions for component coals with the wide range of maximum mean reflectance (Ro), but a significant linear correlation on the contraction/expansion behavior between Sapozhnikov and Ruhr dilatation test is observed for experimental coal blends Ro between 1.00 and 1.20. Sapozhnikov Y results are linearly related to the melting range from both the Gieseler plastometer and the Ruhr dilatometer for all the experimental single coals and coal blends.

Study of the swelling pressure of coals and coal charges in the coking process

The maintenance of furnaces is one of the most important problems for by-product coke production. Swelling pressure is one of the least studied factors affecting the lining of coke furnace walls. The results of studies of the swelling pressure of PJSC “Koks” feedstock coal are presented in this paper. Research has been carried out to identify the dependence of the swelling pressure on the coal quality indicators, estimated during the incoming control of the central plant laboratory of PJSC “Koks”. The plastic properties of PJSC “Koks” feedstock coals were studied using Gieseler plastometer. The relationship between the swelling pressure and the maximum coal fluidity is revealed.

PENGARUH KANDUNGAN ABU DAN ZAT TERBANG TERHADAP MAKSIMUM FLUIDITAS BATUBARA FORMASI TANJUNG DI DAERAH SEKAKO, KALIMANTAN TENGAH

ABSTRAK
 Batubara high – low volatile bituminous Formasi Tanjung di Kalimantan Tengah dikenal berpotensi sebagai coking coals. Maksimum fluiditas merupakan ssalah satu parameter penting yang sangat berkaitan dengan kualitas kokas yang dihasilkan. Penelitian ini bertujuan untuk menganalisis distribusi kandungan zat terbang dan abu serta pengaruhnya terhadap maksimum fluiditas batubara khususnya untuk batubara dari Formasi Tanjung. Batubara diambil dari lapangan di Daerah Sekako dengan channel sampling ply by ply berdasarkan litotipenya kemudian dilakukan analisis laboratorium meliputi analisis proksimat dan analisis Gieseler plastometer. Batubara yang diambil dari 2 seam Formasi Tanjung yang diproduksi tersusun dominan atas litotipe bright coals dan banded bright coals dengan memiliki kandungan abu (ash) 2,79 – 9,05 (wt%, adb), kandungan zat terbang (volatile matter) 35,14 – 39,50 (wt%, adb) dan maksimum fluiditas 22263 – 49029 (ddpm). Kandungan abu berkorelasi negatif kuat (r = -0,656; R2 = 0,431) dan tidak berpengaruh signifikan (sig. 0,055 > 0,05) terhadap maksimum fluiditas batubara. Sementara itu, kandungan zat terbang berkorelasi positif sangat kuat (r = 0,794; R2 = 0,6301) dan berpengaruh signifikan (sig. 0,003 < 0,05) terhadap maksimum fluiditas batubara. Semakin tinggi kandugan abu maka maksimum fluiditas batubara semakin rendah dan sebaliknya semakin tinggi kandungan zat terbang maka maksimum fluiditas batubara semakin tinggi. Hubungan kandungan zat terbang dengan maksimum fluiditas batubara dapat dinyatakan dengan persamaan y = 6327,9x - 200248.

Strength degradation mechanism of iron coke prepared by mixed coal and Fe2O3

Iron coke, as a new type of blast furnace burden is helpful for energy saving, emission reduction and green production of iron making. This study aims to investigate the strength degradation mechanism of iron coke prepared by mixed coal and Fe2O3 to provide a theoretical direction to improve its strength. Coking and pyrolysis experiments of mixed coal and Fe2O3 were carried out between 400 and 500 ℃ temperature. Gieseler plastometer and derivative thermogravimetric (DTG) showed that added Fe2O3 inhibited the thermoplasticity and pyrolysis process of mixed coal during coking. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) results showed that added Fe2O3 decreased the aromaticity and average stacking height, but increased the interlayer spacing of crystallite, aliphatic chain length and hydrocarbon-generating potential of mixed coal during coking. Further, gas chromatography-mass spectrometer (GCMS) analysis suggested that the added Fe2O3 inhibited the cleavage of CalO, CalS, CalN, CalCar and CalCal bonds, reduced the generation of ethylbenzene, o-xylene and unbranched alkanes with carbon atoms in 24–26, thus decreased the amount of fluid phase generated in coking and ultimately degraded the strength of iron coke.

Effects of Fe2O3 addition on the thermoplasticity and structure of coking coal matrix during thermoplastic stage of pyrolysis

Effects of Fe2O3 addition on the thermoplasticity and structure of coking coal matrix were performed by blending Fe2O3 with coking coal matrix during thermoplastic stage of pyrolysis. Thermoplasticity and thermal behavior of coal matrix were characterized by Gieseler plastometer and Thermogravimetry analyzer. Structure of coal matrix at different pyrolysis temperatures during thermoplastic stage was investigated by using X-ray diffraction and Fourier transform infrared spectroscopy. Fluid phase collected from the coal matrix by two-stage extraction was identified by Gas chromatography-mass spectrometer analysis. The results show that the added Fe2O3 decreased the plastic range, maximum Gieseler fluidity and weight loss rate of coal matrix, and inhibited the cleavage of Cal-Cal, Cal-Car, Cal-O, Cal-S and Cal-N bonds during thermoplastic stage. Further, the inhibiting effect resulted from the added Fe2O3 made the decrease of aromaticity and average stacking height, increase of interlayer spacing of the crystallite, and ascending of aliphatic chain length and hydrocarbon-generating potential of coal matrix. Consequently, the formed fluid phase would be reduced, reflected in the disappearance of ethylbenzene, o-xylene and unbranched alkanes with carbon atoms in 24–26, resulting in coal thermoplasticity declining. This contributes to a better understanding of coke strength decrease in producing highly reactive iron coke.

Thermoplastic Properties of Coal and Coal Extract

The aim of this study is to find a simple, effective, and non-destructive way to estimate the fluidity of coal. Three kinds of metallurgical coals were blended in a specific ratio for fluidity measurement by a Gieseler plastometer and coke strength by the Roga test. One of the metallurgical coals was extracted with four kinds of solvents. The solvent-extracted extracts further underwent heat treatment at different temperatures and were then added to the blended coal to examine the change of fluidity and coke strength. Both the heat-treated and untreated coal extracts were further investigated by elemental analysis, thermogravimetric analysis, solid-state 13C nuclear magnetic resonance, and X-ray diffractometry, and it was found that the heat treatment will increase the degree of graphitization. The aromatic carbon content was found to correlate significantly with the fluidity of coal, and the relationship among the ratio of aromatic carbon/aliphatic carbon, aromaticity, and fluidity was studied in this work. Finally, X-ray diffractometry is suggested to be a non-destructive method to estimate the fluidity of coal.

Effects of kaolinite addition on the thermoplastic behaviour of coking coal during low temperature pyrolysis

The presence of kaolinite as mineral in coal may significantly influence coking properties of coal, therefore affects quality of coke that is produced from such coals. In this paper, the effect of kaolinite addition on pyrolysis behaviour of coal was examined by blending kaolinite with a medium rank, high vitrinite, low ash coal. Thermoplasticity of coal was characterised by using a Gieseler Plastometer. Char and tar samples were collected through pyrolysis at 450°C in a Gray-King apparatus. The functional groups of the char samples were measured using FT-IR spectroscopy, while tar compositions were characterised using GC/MS. The results indicated that under the test conditions, addition of up to 5wt% of kaolinite could increase the coal fluidity, attributed to the decrease in CH3/CH2 ratio in the residual char. The proportion of CO/CC bonds affected the plastic range. Furthermore, the results showed that kaolinite addition suppresses the evolution of low molecular compounds in tar phase. This study provides useful information for optimising coal blending in cokemaking industry.

Characterization of microstructure and strength of coke particles and their dependence on coal properties

Microstructural features of coke particles are crucial for determining the performance of cokes in ironmaking blast furnaces. An analytical study was carried out to examine coke microstructure using image analysis. The microstructure parameters were correlated to the tensile strength of cokes. Coke properties were related to coal fluidity data based on Gieseler Plastometer measurements and other coal properties including quantitative mineralogy of coals using SIROQUANT analysis. Based on the microstructural data, a new modified microstructural parameter (S+) is proposed to characterize the heterogeneous nature of the physical structure of coke particles. The modified parameter was shown to have a good correlation with the tensile strength of coke as well as with the plastic range of the parent coals. Coal rank was shown to have a strong influence on the thermo-plasticity, with the results showing that there is an increase in both the maximum fluidity and plastic range of coals with increasing volatile matters of coal. The study highlighted the significance of coal mineral chemistry on coke particle characteristics from the observation that kaolinite-rich coals displayed a better correlation with the proposed modified parameter as well as the coke strength under the tested conditions. Stamp charging is also shown to have a positive impact on the microstructure as well as mechanical strength of cokes. This study has implications for the optimisation of the impact of coal chemistry and process conditions on coke quality.

Some factors influencing the fluidity of coal blends: Particle size, blend ratio and inherent oxygen species

The fluidity performance of blended coals prepared from caking coal and non- or slightly-caking coal of different particle sizes, and the evolution of gaseous oxygen containing compounds (CO, CO2 and H2O) during carbonization are examined using the Gieseler plastometer method, and a flow-type fixed-bed quartz made reactor, respectively. The heating rate and temperature are 3°C/min and 1000°C, respectively. The Gieseler fluidity decreases with increasing blend ratio of non- or slightly-caking coal to caking coal. In addition, the fluidity tends to decrease with the decreasing particle size of non- or slightly-caking coal in blended coals. The evolution of CO, CO2 and H2O during the carbonization of single coals begins at 200–400°C, and the main peak of the formation rate appears at 450–700°C. The amount of gaseous O-containing compounds evolved until 1000°C from the non- or slightly-caking coals is greater than that of evolved from the caking coal. Additionally, a negative correlation is observed between the amounts of CO, CO2, and H2O that evolve up to the initial softening temperature and the maximum fluidity value. The profiles of formation rates of the three gaseous O-containing compounds from the blended coal during carbonization are different with additive average based on the results of single coals. Furthermore, for the blended coal, the starting temperature H2O evolution measured shifts to higher temperature in comparison with that of calculated based on the results of single coals. Therefore, it is possible that the H2O produced from non- or slightly-caking coal in blended coal or that the H2O formation reactions in blended coal during carbonization affects the fluidity performance of the blended coal.

Modelling the Gieseler fluidity of coking coals modified by multicomponent plastic wastes

A novel method for predicting the Gieseler maximum fluidity (Fmax) of a coal+plastic mixture formed from a relative proportion of the plastics present in a multicomponent waste is proposed. A training set of five most-common thermoplastics in household wastes (HDPE, LDPE, PP, PS and PET), binary and ternary plastic mixtures was used to construct multivariable linear regression (MLR) models. Validation was conducted by means of an external set of mixed plastics and real unsorted plastic wastes. The results obtained from the numerical solution of the MLR models were found to be in satisfactory agreement with the experimental data obtained using a Gieseler plastometer. The Fmax values fitted the models with determination coefficients of >0.96 and root mean square errors of prediction of 0.048 and 0.058. All the plastic mixtures tested represented a wide spectrum in concentration of the five polymers contained in municipal plastic wastes and a global plastic addition of 2wt% to the coal was always used. The starting point for this study was to determine the effect of each single plastic on the reduction in fluidity of various coking coals and an industrial coking blend. Afterwards, the exponential functions of Fmax of the blends of coal and binary/ternary plastic mixtures were useful to analyze the changes in Gieseler Fmax with varying proportions of components. Based on the results, the coal responses were statistically treated and MLR models were developed.

浸透現象に着目した石炭の軟化溶融特性の新評価方法

A novel measurement method for coal thermoplasticity was developed, where permeation distance of thermally plastic coal into glass beads layer placed on the coal sample was measured. The characteristic of this method is simulating the condition in a coke oven, especially void structure around the plastic layer by using glass beads and coking pressure by applying a load. In a standard condition, the coal sample is heated to 550 °C, and coal sample softens and permeates into the glass beads layer, then the permeation distance is measured after cooling the sample. The maximum permeation distance measured is roughly correlated with Gieseler fluidity, however large deviation is observed especially for high fluidity coals. Moreover, the deterioration of coke strength is observed in case that long permeation distance coal is used in a coal blend for cokemaking. This new measurement method clearly shows the difference in coking property of high fluidity coal as well as solving the problems in Gieseler plastometer method for evaluating high fluidity coals. By employing the permeation distance method, contribution to the production of high strength coke and effective usage of caking coal will be expected.

The fate of sulfur in coal during carbonization and its effect on coal fluidity

The fate of sulfur during carbonization at 3°C/min of seven caking coals with carbon and sulfur contents of 80–88 and 0.55–1.8mass%-daf, respectively, has been studied using a flow-type fixed-bed quartz reactor to examine its effect on coal fluidity in caking coal. Org.S transfers to H2S or tar-S from 200 to 350°C, and FeS2 decomposes to H2S and FeS above 350°C. The H2S formation rate exhibits two distinct peaks at 450 and 550°C. The amounts of H2S that evolved and Org.S that remained in cokes often depend on carbon contents in raw coals. The maximum fluidity (MF), determined by the Gieseler plastometer method, appears at around 450°C for all of the coals examined, and the values range from 1.1 to 4.1log(ddpm). The MF value tends to decrease with increasing amounts of FeS2 or Org.S remaining in solid products up to 450°C. Sulfur-containing compounds, such as elemental sulfur, FeS2, diphenyl disulfide and dibenzothiophene, added to caking coal adversely affect coal fluidity.

Synergistic effects on pyrolysis of binary and ternary coal blends studied by means of dynamic mechanical thermal analysis and Gieseler plastometer

Desirable values of technological indices of cokes produced from blends containing poor coking coals are expected due to mutual interactions between components during pyrolysis. The aim of this work was to study a synergistic effects postulated to occur during thermal decomposition of the binary (50:50) and the ternary blends of weakly-caking coals (from the Szczygłowice and Krupiński coal mines, Poland), blended with strongly caking coal (from the Zofiówka coal mine, Poland) of increasing content from 10wt.% up to 100wt.% with step of 10wt.%. Pyrolysis of the blends was studied by means of the dynamic mechanical thermal analysis (DMTA) (shortened form is DMA) and the Gieseler plastometer. The results were related to the structure ordering degree of cokes performed from the blends mentioned above. Synergistic effects were detected in all blends, but strength of above was not the same. Divergences between temperature dependence of fluidity measured by the Gieseler plastometer and calculated one from the data of initial coals and their content in a blend under assumption of additivity, were higher for the binary blends in comparison with those of the ternary ones. The greatest synergistic effects were observed for the blends with the strongly caking coal content of 30–50wt.%, for which high ordering of structure was registered. For these blends the greatest dissipation of the oscillation energy supported by the DMA apparatus was observed.

Quality of Some Nigerian Coals as Blending Stock in Metallurgical Coke Production

Two Nigerian coals, Lafia-Obi and Chikila were blended in the mass ratio of 70:30 with imported American and Polish coking coals. Proximate analysis, free swelling index, Ruhr dilatometer and Gieseler plastometer were used in assessing the coking qualities of both the single coals and the blends. The results show that the blends are lower in moisture and ash contents; higher in volatile matter and fixed carbon than the single Nigerian coals. The rheological parameters revealed superiority in thermo-plastic properties of the blends over the unblended local coals. Lafia-Obi/Foreign coals blends possess lower ash and better rheological properties compared to Chikila/Foreign coal composites which have high ash and poor rheological properties. These together suggest that amongst the two Nigerian coals, Lafia-Obi is superior for blending with the foreign ones in metallurgical coke production.

Effects of plastic wastes on coal pyrolysis behaviour and the structure of semicokes

Recently, plastic wastes of different structures and origins (agriculture, municipal, electronic, automobile) have been proposed as minor components of coal blends for metallurgical coke manufacture in order to contribute to the protection of the environment and natural resources. Since an adequate development of coal fluidity in high-temperature carbonization is a prerequisite for producing a graphitizable carbon material of high quality, this paper investigates the role of HDPE, PP, PET and a mixture containing these three thermoplastics in the formation of semicokes, an intermediate carbon material in the transformation of coal to coke. These plastic wastes blended with a bituminous coal in amounts of 1, 2 and 5 wt.% cause a decrease in coal fluidity as measured by the Gieseler plastometer, the extent of the reduction being dependent on the amount, the structure and the thermal behaviour of the plastic waste added. Model hydrocarbons have been used to explain the differences in the fluidity of the blends with HDPE and PP. Evidence of the incorporation of HDPE into the carbon matrix of semicokes comes from diffuse reflectance infrared spectroscopy and scanning electron microscopy as well as from the study of the evolution of volatile products in the post-plastic stage of coal by thermogravimetry coupled to mass spectrometry. The non-agglomeration of blends with PET is clearly observed by SEM and optical microscopy, the latter revealing the isotropic nature of the resultant semicoke.

Viscoelastic properties of coal in the thermoplastic phase

The viscoelastic properties of coals in the thermoplastic phase during carbonization were measured with dynamic mechanical oscillation instrumentation. The temperature and frequency dependence of the viscoelastic properties of the coals in the thermoplastic phase were similar to those of polymers and thermosetting resins. The storage modulus (G′) and the loss modulus (G″) showed minimum (104–105Pa), the loss tangent (tanδ=G″/G′) showed a peak, and the complex viscosity (η∗) also showed a minimum (104–105Pas) near the temperature of maximum fluidity of coal. There was a close relationship between the caking characteristic parameters measured with conventional method and the rheological moduli obtained here. The complex viscosity (η∗) decreased as the frequency increased, which suggests that the conventional Gieseler plastometer overestimates the fluidity in the high fluidity range due to the high rotation speed. It proved promising to apply the dynamic viscoelasticity measurement technique to study the coal structural changes during the thermoplastic phase from analogy with polymers.

軟化溶融石炭の動的粘弾性挙動

The viscoelastic properties of coals in the thermoplastic phase during carbonization were measured with dynamic mechanical oscillation instrumentation. The temperature dependence and frequency dependence of viscoelastic properties of the coals were similar to those of polymers and thermosetting resins and this method proved promising in studying the coal structural changes during thermoplastic phase from the analogy to polymers.As the coals started to soften, the storage modulus (G') and the loss modulus (G'') decreased and the loss tangent (tan δ=G''/G') increased. While for the caking and slightly caking coals tanδ exceeded unity which showed that the bulk structure of the coal was flowing, for the non-caking coal it was lower than unity in the whole temperature range. Near the temperature of maximum fluidity, tanδ showed a peak while G' and G'' minimum (104-105 Pa) and the complex viscosity (η*) also minimum (104-105Pa·s). Further increase in temperature decreased tanδ and the gel point where tanδ=1 was reached near theresolidification temperature. There was a close relationship between the caking characteristic parameters measured with conventional method and the rheological moduli obtained here. The difference in G' near the resolidificationtemperature among the coals suggested that the compressibility of semi-coke layer could be evaluated by this method.The frequency dependence of the viscoelastic properties of coal was measured at 450°C. As cure reaction proceeded, the crossover point of G' and G'' shifted toward low frequency side. This shift might be correlated to the molecular weight and molecular weight distribution of the coal in plastic state. Furthermore η*decreased as the frequency increased which suggests that the Gieseler plastometer overestimates the fluidity in high fluidity range due to the high rotation speed.

First production from Liverpool Bay

A pressure-temperature microscopy system (PTM) has been developed for obtaining observations on coals and heavy hydrocarbons at elevated temperatures and hudrogen pressures commonly used in the hydroprocessing of coal, coal liquids, and petroleum residua. A Pittsburgh #8 seam coal, from near New Eagle in Washington County located south of Pittsburgh, Penna., was extensively characterized by petrographic analysis, proximate and ultimate analysis, Gieseler plastometer, and Ruhr dilatometry as well as data on grindability, ash characteristics, and oxidation properties. Novel direct microscopic observations at elevated temperatures and pressures with catalysts give observable changes in phase transition behavior of coal. Direct microscopic observations of fresh vitrain particles at elevated temperature and high nitrogen pressure in the presence of a tin chloride catalyst show plastic deformation. Upon replacement of nitrogen by pressurized hydrogen, individual vitrain particles are observed to liquefy in the presence of molten tin. After liquefaction, further temperature increase at 1950 psig hydrogen results in the formation of mesophase and the segregation of the molten tin.Pressure-temperature microscopy is also presented on the liquefaction behavior of a solvent-refined coal (SRC) from Wilsonville, Ala. Additional pressure-temperature microscopy is presented on the tin-catalyzed co-liquefaction behavior of the solvent-refined coal with the Pittsburgh #8 seam vitrain. The pressure-temperature microscopy of the liquefaction experiments and mesophase development have been video recorded and are available for viewing.

A characterization method and model for predicting coal conversion behaviour

This paper considers the development of a predictive macromolecular network decomposition model for coal conversion which is based on a variety of modern analytical techniques for coal characterization. Six concepts which are the foundation of the functional group-depolymerization-vaporization-cross-linking (FG-DVC) model are considered: 1. (1) The decomposition of functional group sources in the coal yields the light gas species in thermal decomposition. The amount and evolution kinetics can be measured by t.g.-FT-i.r., the functional group changes by FT-i.r. and n.m.r. 2. (2) The decomposition of a macromolecular network yields tar and metaplast. The amount and kinetics of the tar evolution can be measured by t.g.-FT-i.r. and the molecular weight by f.i.m.s. The kinetics of metaplast formation and destruction can be determined by solvent extraction, by Gieseler plastometer measurements and by proton magnetic resonance thermal analysis (p.m.r.t.a.). 3. (3) The molecular weight distribution of the metaplast depends on the network coordination number (average number of attachments on aromatic ring clusters). The coordination number can be determined by solvent swelling and n.m.r. 4. (4) The network decomposition is controlled by bridge breaking. The number of bridges broken is limited by the available donatable hydrogen. 5. (5) The network solidification is controlled by cross-linking. The changing cross-link density can be measured by solvent swelling and n.m.r. Cross-linking appears to occur with evolution of both CO 2 (before bridge breaking) and CH 4 (after bridge breaking). Thus low-rank coals (which evolve much CO 2) cross-link before bridge breaking and are thus thermosetting. High-volatile bituminous coals (which form little CO 2) undergo significant bridge breaking before cross-linking and become highly fluid. Weathering, which increases the CO 2 yield, causes increased cross-linking and lowers fluidity. 6. (6) The evolution of tar is controlled by mass transport in which the tar molecules evaporate into the light gas or tar species and are carried out of the coal at rates proportional to their vapour pressure and the volume of light species. High pressures reduce the volume of light species and hence reduce the yield of heavy molecules with low vapour pressures. These changes can be studied with f.i.m.s. The paper describes how the coal kinetic and composition parameters are obtained by t.g.-FT-i.r., solvent swelling, solvent extraction and Gieseler plastometer data. The model is compared with a variety of experimental data in which heating rate, temperature and pressure are all varied. There is good agreement with theory for most of the data available from the authors' laboratory and in the literature.

ＮＥＤＯＬ法液化残さの熱流動性と酸化改質

Themoplastic property of liquefaction residue produced at NEDOL lt/d Process Supporting Unit using Wandoan and Wyoming coals was studied by Gieseler plastometer under atmospheric and elevated pressure. Effect of air oxidation on thermoplasticity was also investigated. Gieseler fluidity of residue was successfully reduced to zero by air oxidation at 150°C. Pressure dependency of fluidity of oxidized residue was different from that of caking coal. Fluidity was more reduced under higher pressure. Photoacoustic FT-IR spectra were measured for oxidized residues. Oxidation of residues was also observed in-situ by diffuse reflectance FT-IR spectrometer equipped with controlled environment chamber. IR spectra obtained showed that oxidation reaction of residue seemed to be similar to that of coal. Increase in absorption at around 1700 and 3400cm-1 along with decrease in absorption at 2800 to 3050cm-1 was observed as oxidation reaction proceeds, indicating formation of carbonyl and hydroxyl groups and dehydrogenation from methylene group mainly in aliphatic compounds.