A coal pyrolysis experiment is carried out to clarify the tar yields of devolatilization products in the range of heating rate (from 0.5 to 20K/s) and to clarify the molecule structure of tar evolving from coal. The tar yield increases with the heating rate. The tar components subjected to rapid heating contain a larger amount of aromatic hydrocarbons than do those subjected to slow heating.

View full abstract

In this study, a new measurement method for coal plasticity was developed, where permeation distance of thermally plastic coal into glass beads layer placed on the coal sample was measured, because conventional coal plasticity such as Gieseler Fluidity had some problems. The characteristics of this method was simulating the condition in a coke oven, especially void structure around the plastic layer by glass beads and coking pressure by applying the load. In a standard condition, the coal sample was heated to 550℃, and coal sample softened and permeated into the glass beads layer, then the permeation distance was measured by image analysis technique. The maximum permeation distance measured was roughly correlated with Gieseler Fluidity, but large deviation was observed especially for high fluidity coals. Moreover, deterioration of coke strength was observed in case that high permeation distance coal was used in a coal blend for cokemaking. This new measurement method clearly showed the difference in coking property of high fluidity coal as well as solving the problems in Gieseler Test for evaluating high fluidity coals.

View full abstract

Effect of stearic acid calcium and graphite on sliding characteristics of the coal was investigated. As the particle size of the graphite was smaller, the bulk density became higher. The coke strength improved at graphite addition rate 3%, but the strength was deteriorated by lack of bond strength of coal particles in more than 3%.

View full abstract

Residue coal was activated by KOH to prepare the Activated carbon(AC). KOH activation of residue coal produced AC with large amount of macropore up to 0.94cc/g. The adsorption rate of 1.1.1 -trichloroethane to AC from KOH activation of residue coal was greater than that of the ordinary activated carbon with little amount of macropore.

View full abstract

Utilization of low rank coal for iron making in a blast furnace is very difficult due to the structure of coal. We tried to coke low rank coal using oil-sand bitumen (OSB) as a binder, and evaluated the obtained coke by several methods including Raman spectroscopy and a polarization microscope. We evaluated the strength/structure of coke prepared from blended coal with/without OSB as a binder. Experimental results revealed that the utilization of OSB as a binder could be an effective way to coke the blended coal to obtain better performance.

View full abstract

We participate in a NEDO project called COURSE50 (CO_2 Ultimate Reduction in Steelmaking process by innovative technology for cool Earth 50), in which we aim to apply HPC as a caking additive to make strong coke for the iron blast furnace, which maximize the use of hydrogen as a reductant in order to minimize coke addition to the furnace. Coke gasification reaction by H_2O, the water-gas reaction, will be increased by increasing in the hydrogen reduction in the blast furnace. The influence of the water-gas reaction on coke strength after reaction was investigated in this study. The reaction rate of the water-gas reaction was estimated about three times to the coke gasification reaction by CO_2, the Boudouard reaction, but significant difference of the coke strength after reaction was not appeared in both after the water-gas reaction and the Boudouard reaction comparing at the same percent of the conversion. HPC additional coke performed to maintain higher strength after reaction due to the effect to form higher connectivity of coke matrix.

View full abstract

We participate in a NEDO project called C0URSE50 (CO_2 Ultimate Reduction in Steelmaking process by innovative technology for cool Earth 50), in which we aim to apply HPC as a caking additive to make high strength coke for the blast furnace, which maximize the use of hydrogen as a reductant, in order to minimize carbon addition to the furnace. In this study, we investigated the effect of HPC addition on coke strength after reaction using spherical coke. Coke strength after reaction tended to be higher by HPC addition in both reactions of Boudouard reaction and water gas reaction at the same reaction conversion. Those effects were confirmed by measurement of the coke diameter after reaction.

View full abstract

Thermoplastic properties of coal and coal with "High Performance Coking additive, HPC" are investigated by means of ^1H-NMR relaxation measurement from the viewpoints of molecular mobility. High temperature ^1H-NMR relaxation measurement enable to monitor the actual changes in progress of thermal transformation. The quantitative change of specimens can be evaluated by recording the hydrogen content of residual specimens, and qualitative variation of the specimen is able to detect as a change of the relaxation characteristics of signal. In this study, it is confirmed that ^1H-NMR re laxation measurement is the appropriate dynamic measurement technique to characterize the thermoplastic properties of coal. The results obtained from ^1H-NMR relaxation measurement demonstrated that the improvement of the thermoplasitic phenomenon of coal with HPC is evaluated both qualitatively and quantitatively by the variation of IHm and T2Hm. It is also investigated that the properties of HPC is affected with the feedstock of HPC.

View full abstract

We have been studying the cokemaking properties of ASC (Artificial Super Coal) produced by thermal-hydrogenation processing of brown coal. In the cokemaking process, using the ASC as coking additive for blended coal, even a condition to satisfy DI might not satisfy CSR. Considering the oxygen content of the ASC is too high, the development of the aromatic carbon structure should be insufficient. In this paper, we examined CO_2 gasification reactivity of the coke which influenced CSR.

View full abstract

For the detailed average structure analysis of heavy hydrocarbons, the determinations of (1) tertiary and quaternary aromatic carbon distributions by ^<13>C-NMR using dept and quat methods, (2) carbonyls by FT-IR, and (3) hydroxyl groups by acetylation with trifluoroacetic acid anhydride followed by ^<19>F-NMR were performed besides the normal analyses. The detailed structures of aromatic rings were estimated using those data.

View full abstract

Rayleigh scattering behavior of asphaltene dispersed in toluene and toluene-pentane mixed solvent (5-20% pentane in toluene) was monitored at a wide range of concentration (20-100,000 mg/L) using a multi channel photo detector (λ=600-1000 nm). A parameter derived based on Rayleigh law was suitable for quantitative evaluation of the degree of aggregation under various solvent conditions.

View full abstract

The amorphous silica-titania and silica-zirconia held large mesopore can be prepared by gel skeletal reinforcement. The mixed catalyst which included only 25% of β zeolite showed higher activity as compared with β zeolite single. In addition, the multi branch product largely increased using the mixed catalyst compared with β zeolite single.

View full abstract

We have recently proposed a coprocessing method of low-grade carbonaceous resources and a low-grade iron ore consisting of FeO(OH) in order to produce both light oil and a raw material for iron making called iron ore/carbon composite (IOC). In the proposed method the carbonaceous resource is expected to fill up the layered pore space of 0.8 nm wide which was formed by the dehydration of FeO(OH) up to 3000℃. Then, the carbonaceous resource in the pore space can catalytically be cracked to produce light oil in high yield over 400℃. The resulting low-grade iron ore consisting of Fe_2O_3 and containing coke in the pore space, can be utilized as the IOC realizing rapid reduction of iron ore. In this study it was clarified that the method was more effective for thermoplastic materials such as heavy oils and waste plastics. For non-thermoplastic materials such as low-rank coals, it was shown that hot press pretreatment or hot solvent pretreatment could enhance the contact between the carbonaceous materials and iron ore, resulting in the production of higher-quality IOC.

View full abstract

The carbon number of average aromatic ring and aliphatic side chain in coal were estimated on the basis of the information obtained by the thermodynamic evaluation of heating value. Molecular formulas of one hundred ranks of coals that reveal their size of aromatic and naphthenic rings were proposed.

View full abstract

Average molecular formulae of 100 types of coal in the JCOAL coal bank were estimated from their chemical structure, and related to the XRD parameters corresponding to their development of stacking structure of carbon hexagonal layers. The stacking structure tended to be developed as the layer size increased, showing that van der Waals interaction between layers had stronger effect on the development of stacking structure as layer size increased.

View full abstract

Hyper-coal (HPC) is an ash-free coal produced by the solvent de-ashing technology. Coal is thermally (360-400℃) extracted into the coal-derived solvent (two ring aromatics). HPC has excellent thermoplasticity and large potential for coke additive to make a strong coke. The yield of HPC depends on the coal solubility. And the solvent must be recovered completely by distillation. So, it is important for HPC process to use a solvent that have not only high solubility of coal but also enough recovery ratio. In this study, we focused on a Washing Oil (WO) that is distillated from coal tar. WO is known to have high solubility of coal. The key compounds for high solubility were cleared, and the recoverability of those compounds was examined.

View full abstract

Ignite Energy Resources Limited ("IER") is an Australian unlisted public natural resource and energy technology company. In 2012, IER establish Ignite Resources Pty Ltd ("IR"), a wholly-owned subsidiary oflER. IR is the most attractive investment proposition in Victoria's largest coal region, the Gippsland Basin. IR holds the right to explore for the surface recoverable brown coal, lignite, within EL 4416, and brings a global license to utilize IER's patented catalytic hydrothermal reactor ("Cat-HTR") technology to upgrade the energy density of lignite to synthetic crude oil and produce an upgraded coal with similar characteristics to PCI type coal. IR plans imlement Cat-HTR demonstration project in Victoria, Australia by utlizing Government grant "Advanced Lignite Demonstrtion Program".

View full abstract

Thermal-hydrogenation reaction of woody-biomass was carried out in a hydrogen-donor solvent by using a 50ml batch-type autoclave, and a bituminous pitch was obtained by vacuum distillation. Coking test of the pitch was performed at 1000℃ for 30 min under a N_2 atmosphere, and the products (cokes) were observed by a polarization-microscope. The pictures clearly showed that optically anisotropic textures well developed in the cokes derived from the pitch produced at 400 - 410℃, which indicated that the pitch could be used as a substitute of coaltar pitch.

View full abstract

Although lignite has spontaneous combustion problem with higher moisture, its needs as new fuel coal of electric power plants are growing with increasing coal demands in emerging countries. Resource quantities and qualities of the lignite is not enough summarized because of its closed market. This report analyzed which countries have much lignite resources around Japan based on those production and utilization around the world extracted from coal quantity information, and discussed quantity of each coal mine in those countries to find the conformity coal. The country analysis extracted Indonesia and Australia with the conditions:producing the lignite more than 20 million tons; distance to Japan is in transportable; and relatively have incentive to export the lignite in closed market.

View full abstract

We analyzed the costs of lignite at power plants in Japan considering transportation costs and technical data of drying processes such as a dewatering-in-oil method that has dewatered lignite avoid spontaneous firing and transported to Japan. The analysis shows the costs of lignite dried on site in the export countries are cheaper at power plants in Japan than the costs of lignite dried in Japan and are competitive with bituminous coal. This is because the on-site drying can reduce contained water transportation and use low cost lignite before transportation for fuel to the drying process.

View full abstract

Coal-fired power generation stays on the significant position due to the rich coal resources in China. It is necessary to reduce CO_2 emission not only in generating electricity but also in coal transportation because energy producing and consuming regions are geographically distinct. We have estimated CO_2 emission reduction potential in coal transportation in the case of ultra super critical power plant (USC) by an optimization model using a Geographic Information System (GIS) and a liner programming (LP) analysis model. The amount of CO_2 emission reduction in transportation is estimated to be 10.2 Mt-CO_2.

View full abstract

In recent years, energy consumption increases with rapid economic development in China. Most of the energy consumption in China has now been supported by coal. In this study, we have evaluated SO_2 exposure from coal-fired power plants in urban region of China. Two coal-fired power plants are assumed as emission source points in Taiyuan City and Yuncheng City, Shanxi Province as a case study. The population distribution map ruled into 1km squares has been prepared using Geographic Information System (GIS). The distribution of SO_2 concentration was then calculated by means of a Gaussian Plume Model. Two cases on the coal plants with and without desulfurization are considered in order to evaluate the amount of SO_2 exposure on the surrounding residents. As the result, the maximum SO_x ex.posure with the desulfurization case is expected to decrease 71%, though that without desulfurization case is estimated to be 295.2mg/m^3.

View full abstract

The mode of occurrence of mercury in coal was investigated by the mild pyrolysis method, in which a coal sample was heated at 300℃ under a nitrogen flow. The mercury present in pyrite tended not to be removed by the 300℃-pyrolysis. For some coals, the deviation in data was quite large when the determination of mercury by an automatic mercury analyzer was performed. The degree of deviation was not dependent on the particle size distribution of coal, and the deviation was fairly canceled when more ground coal samples were used. The possibility of localization of mercury in a microscopic level m coal was discussed. For other trace elements, such a deviation in data was not observed.

View full abstract

The most popular method for mercury removal is powdered activated carbon injection (PAC) into flue gases. However, it is recognized that the PAC has some drawbacks such as high cost, narrow working temperature window, and releasing mercury into soil. The objective of this study is to investigate characteristics of mercury oxidation by ozone injection generated by atmospheric pulsed plasma and its water-solubility in a wet scrubber. Hg_0, NO (nitric oxide), and Hg_0+NO gas mixture were used as simulation gas. Above 95% Hg_0 and NO removal was attained by ozone injection.

View full abstract

Boron and selenium exist as gaseous and particle phases in coal flue gas. They are partitioned into four components, bottom ash, fly ash, FGD waste water, and emission gas discharged into the atmosphere. The ratio of the components varies depending on coal properties and combustion conditions. Therefore, it is necessary to measure these components accurately to understand boron and selenium's behaviors during coal combustion. In this study, we developed the optimum sampling methods for gaseous boron and selenium using a new absorbent and a solvent for rinsing sampling tubes. Also, we collected data at a turbulent furnace test facility to discuss material balances and the behaviors of boron and selenium.

View full abstract

In pulverized coal combustion boiler, ash deposits such as slagging and fouling prevent heat transfer. On the other hand, a reserve of high lank coal is limited. So co-combustion of low lank coal, that is inexpensive, and high lank coal has been carried out in pulverized coal combustion boiler. Generally, low lank coal includes ash of low melting point. However, in this situation, ash deposition behavior has not been clarified. The purpose of this work is elucidation of ash deposition behavior during co-combustion in pulverized coal combustion boiler. Ash deposits were collected on a heat transfer tube with an ash deposit experiment at some blend condition. Ash particles near the adhesion interface were analyzed about element distribution by a Scanning Electron Microscope and an Energy Dispersive X-ray (SEM/EDX). And ash particles are also analyzed about composition and particle size distribution by a Computer Control Scanning Electron Microscope (CCSEM). We calculated the molten fraction of each mix condition ash by chemical equilibrium theory, using FactSage Ver.6.3.1 software.

View full abstract

In general, the use of coal having different physical properties from those of design coal in a pulverized coal combustion plant causes ash deposit troubles, such as fouling and slagging. However, from the viewpoint of utilization of low rank coals, flexibilities for various coal types as fuel are going to be required in pulverized coal fired boilers before long. Then, it is important to preliminarily predict mineral particle behaviors in coal combustion process. In this study, their behaviors are studied by use of artificial coal samples which contains included minerals and excluded minerals. Coal samples are burned in a drop tube furnace to sample particles in different conversion ratio and residence time. Then included and excluded minerals are analyzed and classified in particles by CCSEM

View full abstract

Recently, oxy-fuel coal combustion has drawn attention as useful technique to achieve carbon dioxide capture and storage (CCS). This is the technique that enriches CO_2 in exhaust gas by the flue gas recirculation with additional pure O_2 to combustion atmosphere, which makes easy to capture CO_2. 0n the other hand, bubbling fluidized bed coal combustion has advantages of direct sulfur capturing in furnace by adding desulfurizing agents to bed material and decreasing of thermal NO_x as a result of low combustion temperature. However, oxy-fuel combustion behavior of coal in a bubbling fluidized bed is still unclear. In this study, we conducted the coal burning experiment under CO_2/O_2 using bubbling fluidized bed and compared oxy-fuel combustion behavior with air combustion behavior of coal. In addition, three coal samples having different nitrogen contents were tested to estimate the effect of raw coal properties on oxy-fuel combustion behaviors.

View full abstract

The purpose of this study was to discuss burn-out characteristics of coals with different swelling characteristics under high temperature combustion conditions. For this purpose, 6 types of coals with different CSN (Crucible Swelling Number) were tested using a drop tube furnace. After these tests, coal chars were sampled to analyze LOI and char morphologies. The analysis results showed that LOI values of swelling coals were higher than those of non-swelling coals. The detailed SEM analysis revealed that the char samples from swelling coals have representative structural variations. This paper discusses burn-out characteristics of each coal in relation to swelling characteristics.

View full abstract

Catalytic decomposition of pyridine (C_5H_5N) with an Australian α-FeOOH-rich limonite ore has been studied with a vertical, cylindrical quartz reactor to develop a novel hot gas cleanup method of removing the nitrogen present in tar as N_2. The limonite achieves the almost complete decomposition of 100 ppmv C_5H_5N in inert gas at 500℃ under a large space velocity of 51000 h^<-1> and maintains the high activity at least for 10h. The limonite can also give high N_2 yield of more than 85%, and the yield is almost constant for 10h reaction. The XRD analyses reveal that α-FeOOH in the limonite is transformed into metallic iron (α-Fe) with the average crystalline size of 25 nm upon H_2 reduction at 500℃. It is thus probable that the finely dispersed α-Fe can catalyze N_2 formnation from pyridine.

View full abstract

This study focuses on the syngas production by partial oxidation of coke oven gas (COG). The reforming of COG, which is a multi-component mixture, in a turbulent flow includes various complex processes. Previous studies were limited to the results using simulated gas with a laboratory scale small reactor and a laminar flow. In this study, we developed a model which considers both chemical reactions and fluid dynamics for simulating the reforming characteristics of the actual COG in a bench scale relatively large reactor. The detailed chemical kinetic model which consists of more than 2000 elementary reactions and 257 species was reduced to 410 reactions and 47 sepcies for realizing coupling a finite rate reaction model with the turbulence model. Numerical simulations could fairly reproduce the reformed gas compositions and temperature profiles in a reformer.

View full abstract

The study aimed to examine the effect of CO_2 environments during pyrolysis of solid fuel on the gasification of its char by using thermobalance. The lignin which had high concentration of Na was pyrolyzed at heating rate of 1 K/s to 973 K under CO_2 and Ar, and these chars were gasified in air at 973 K. It was found that carbonate formed, and chemical form of Na significantly varied during pyrolysis under CO_2. The change of chemical form of Na inhibited gasification reaction.

View full abstract

The coal pyrolysis is the important reaction that has much influence on initial situations in coal combustion and gasification processes. The authors recently proposed the extended CPD model. This model can describe primary tar compositions as actual chemical species. As a result, it became possible to calculate the gas phase decomposition behavior by using a gas phase reaction mechanism in existence. CO_2,O_2 and H_2O gasification experiments on 2 types of coal were simulated by combining the cxtended CPD model, a gas phase reaction mechanism and char gasification models. The soot yield did not decrease in CO_2 gasification, while it decreased in O_2 or H_2O gasification. These phenomena were described by the simulation well. Furthermore, it was suggested that the mechanism to decrease soot (PAH) was different between O_2 and H_2O.

View full abstract

Pyrolysis oil of wood (woody tar, WT) and a mixture of WT and vanillin (10%) was partially hydrodeoxygenated using a continuous-flow slurry-bed reactor, and the oxygen content of them was reduced to around 10%. The hydrodeoxygenated oil (HWT) was separated into light, middle distillates and bottom (>360℃). The recycle use of the bottom and catalyst recovered was also tested. The middle distillate (HWT-MD, 240〜360℃) was co-hydrotreated with petroleum LGO using a continuous-flow fixed bed reactor. Since the nitrogen content of HWT-MD(1700ppm) was much higher than that of LGO (40ppm), the HDS reaction was inhibited significantly by the addition of HWT-MD.

View full abstract

It is necessary to get basic knowledge that contributes the high co-firing rate use of the woody biomass for CO_2 reduction. In this study, the single-firing characteristics using a cedar as a woody biomass with a pulverized coal fired burner was compared with that of coals by a coal combustion test facility. The NO_x concentration at the exit of furnace in the single-firing a cedar became very lower than that of coal firing. The combustion efficiency of cedar was extremely higher than that of coal. The combustion process of a cedar near the burner was different from that of coal greatly. The ignition of pulverized cedar was easily in the cold state without pre-heating or assistant fuel.

View full abstract