Currently, pulverized coal is blown into blast furnaces to reduce the amount of coke used in the steelmaking process. On the other hand, in recent years, the grade of coal has been declining due to the increase in the use of coal, and the company has been forced to respond to the diversification of coal types. Therefore, in this study, we used a batch furnace to prepare three types of coal char, and then the cross-sectional observation of the char by SEM and specific surface area analysis by BET method using N₂ were carried out. Coal with porous particles and high specific surface area values was found to have very high gasification reactivity for both CO₂ and H₂, while coal with balloon-type particles with large cavities inside the particles and low specific surface area values was found to have lower gasification reactivity.

Oxy-Fuel combustion is one of the techniques to achieve carbon dioxide capture and storage (CCS). Meanwhile, fluidized bed combustion has the advantage of increasing combustion efficiency due to particle flow. Oxy-fuel coal combustion in a fluidized bed is a relatively new study, so the combustion behavior remains unclear. In this study, we investigated Oxy-fuel coal combustion behavior by comparing three combustion atmospheres, air, CO₂-O₂ and Oxy-Fuel using bubbling fluidized bed reactor. Especially in this research, we focused on the production of SOx, and in Oxy-fuel combustion, the concentration of SO₂ increased due to the effect of recirculation. Regarding SO₃ generation in Oxy-fuel combustion, the concentration became high due to the influence of SO₂ circulation and H₂O circulation.

An analysis was performed by combining the TPD and CVAAS to identify and quantify the mercury forms in the fly ash produced from a coal-fired power plant. The TPD curve of the model sample for each mercury compound showed a unique peak temperature, and the chemical form of mercury was identified by comparing the peak temperature with that of the fly ash. A linear combination of the TPD curve of each model sample was curve-fitted to that of the fly ash. The calculated results revealed that 45% of total mercury is C-Hg in the fly ash followed by HgO, HgS, HgSO₄･2HgO, HgSO₄ with around 14%.

In coke manufacturing, the dilatation of coal is a crucial factor affecting the quality of coke. Coal is generally used by blending several sorts from different locality. However it was revealed that the dilatation of coal doesn’t hold weighted average. Therefore coal blending technology is important for manufacturing high quality coke. In the previous study, it was investigated the inhibitory influence of low rank coal on high rank coal. And the inhibitory influence is defined “Inert Factor”. In this report, the inhibitory influence of petroleum coke, powder coke and low rank coal (TD=0%) on coking coal using previous study method. As the result, when a carbonaceous material (petroleum coke, powder coke and low rank coal) that does not soften and melt is added to the raw coal, it was observed that the inhibitory influence.

Coal is softened in carbonization, and its fluidity occurs. In the present study, to theoretical investigate the fluidity of coal, we assumed that coal in softening was fluid and performed numerical simulations for coal in softening at the Gieseler fluidity tests using computational fluid dynamics. As a result, the Gieseler fluidity, viscosity, and non-Newtonian fluidity of the coal would affect its fluid flow in the Gieseler fluidity tests.

To observe oxygen functional groups generated during oxidation reaction, coal was treated at 40–120 degree C under ¹⁷O₂ atmosphere. Solid state ¹⁷O MAS NMR spectra of the oxidized coal were acquired by using Oldfield Echo pulse sequence. Since the ¹⁷O MAS NMR spectrum acquired by Single Pulse sequence suffered from distortion caused by ringing phenomenon, the Oldfield Echo pulse sequence was used to eliminate the spectral distortion. As a result, two kinds of oxygen functional groups generated by oxidation were observed. Furthermore, these areas of ¹⁷O NMR spectra became large as oxidation temperature was high, indicating that the amount of oxygen functional groups increased with an increase of oxidation temperature.

Utilization of low-rank coals, such as lignite and subbituminous coal, in pulverized coal thermal power plants is important for fuel cost reduction and energy security. However, most of these coals have high propensity for self-heating and run the risk of ignition during pulverization in the roller mill. In this study, the self-heating rate of pulverized coal deposits was measured by the wire basket method, and the concentrations of CO and CO₂ were measured simultaneously by gas chromatography. The results showed that the initial self-heating rate of coals were correlated with the concentrations of CO and CO₂. Thus, gas measurement is considered suitable for evaluating the self-heating characteristics in a roller mill.

Carbonization and torrefaction have been performed in biomass energy utilization. We need to choose the best carbonization condition in manufacturing, because the good fuel char would be produced. The data of fuel characteristics has the influence on carbonization operation. So, it is required the measurement technology which can reveal the fuel characteristics of carbonized biomass in manufacturing plants. In this study, we develop the evaluation method of fuel characteristics by measuring the color of carbonized biomass. In the experiment, we conducted the carbonization of woody biomass, cellulose, xylose and lignin. And we evaluated the characteristics of carbonized samples on elements, heating value and color. Then we considered the relation between fuel characteristics and color change of carbonized biomass. So, the measuring the color of carbonized biomass could be a one of the evaluation method to reveal the fuel characteristics, because there was the positive correlation between heating value and color distance.

The transport phenomena of dropping of liquid in a narrow space between particles assuming a countercurrent packed bed were analyzed by using computational fluid dynamics. A liquid lump was arranged on the top of the narrow space. The effects of the distance between particles and airflow from the bottom of the analytical object on numerical results were investigated. As a result, the liquid was difficult to flow at the small distance, and the airflow inhabited the dropping liquid.

In coal gasification process, char gasification reaction is the rate-determining step. We had proposed PS-LH model with taking account of competitive reactions between CO₂ and H₂O. We had determined 9 coals’ char gasification reaction model parameters through a pressurized drop tube furnace and a thermogravimeter. The models are composed of chemical reaction on active sites (PS-LH), changing of pore structure or specific surface area (Random pore model) and diffusion control part at high temperature (Fletcher model). In this study, correlation between these parameters and coal property data are investigated. As a result, gasification reaction parameters of char prepared at high temperature have a significant correlation with fuel ratio, calcium concentration and oxygen content.

Since April 2012, Osaki CoolGen Project has been conducted as an “IGFC(Integrated coal Gasification Fuel Cell combined cycle) demonstration project” with the support of Ministry of Economy, Trade and Industry (until 2015 FY), and New Energy and Industrial Technology Development Organization (from 2016 FY). This project consists of the following three steps. In the Step1, oxygen blown IGCC (Integrated coal Gasification Combined Cycle) was demonstrated. In the Step2, IGCC with CO₂ capture is being demonstrated. In the Step3, IGFC with CO₂ capture will be demonstrated. Demonstration of the Step1 was conducted from March 2017 to February 2019. Development targets of plant efficiency, environmental performance, reliability, operability, coal variety compatibility and economic efficiency were achieved. This paper describes progress of Osaki CoolGen Project.

CCS is regarded as a method to reduce CO₂ emission. Huge energy is required to capture CO₂ from exhaust gas of thermal power station, thermal efficiency decreases and cost of electricity increases. The oxy-fuel IGCC system is under development to solve this problem, by Central Research Institute of Electric Power Industry (CRIEPI), Mitsubishi Heavy Industries Co. ltd. and Mitsubishi Hitachi Power Systems Co. ltd. as NEDO (New Energy and Industrial Technology Development Organization) funded project. This system is composed of O₂/CO₂ blown gasifier and semi-closed cycle gas turbine, and the system is expected to keep high efficiency more than 42% at HHV after CO₂ capture. CRIEPI runs several experimental researches and numerical simulations. This report is to update net efficiency estimation data depending on results acquired by 3-Dimensioanl numerical simulation on coal gasifier including gasification and combustion reaction and particle behavior, and to estimate impact of CO₂ purification on efficiency.

We have proposed a novel highly-efficient power generation method in which low-rank coal or biomass reduces liquid phase metal ions and subsequently electric power is generated by electrochemical oxidation of the reduced ions by air. Whereas power generation efficiency by brown coal or biomass using a conventional boiler is only 10–30 %, theoretical power generation efficiency of the proposed method can be estimated to be as high as 80% if VO²⁺ or Cu²⁺ is employed as metal ions for example. In this study we have carried out a kinetic study to formulate the rate of the reaction between a brown coal and VO²⁺ and showed that the rector size of the proposed method can be comparable to the boiler generating the same electric power.

In the present study, nitrogen release mechanisms in coal gasification reactions were studied by using gasification reaction kinetics. Based on previous experiments, models for the nitrogen release ratios from the char in proportion to the carbon release ratios were devised. The models to release the nitrogen from the char as NH₃ or HCN were investigated. The models to release the nitrogen from the char as NH₃ in H₂O and CO₂ gasification and HCN in O₂ gasification were most consistent with the experimental results.

The self-heating properties of 3 dried coals were measured using the adiabatic tester at a temperature range of about 40~100°C and the concentrations of CO and CO₂ gas generated from the coals were analyzed simultaneously. The adiabatic self-heating test results showed that the temperature increase rate was higher as the O/C of coal was higher. The gas analysis showed that the higher the self-heating rate, CO and CO₂ generation rates was higher. Moreover, it was found the rates of the temperature increase were correlated with CO generation rates and there was small difference in coals in terms of total amount of CO and CO₂ generated from 40°C to any temperature.

To characterize chemical structure of oxidized coal, solid state ¹³C NMR spectra were acquired for two kinds of coal X and Y before and after estimation of their self-heating property by using R70 apparatus. It was found that coal X with higher oxgen concentration reached 80°C in shorter time than coal Y. The oxygen functional group most generated in coal Y during oxidation was found to be aldehyde and ketone, while that in coal X was found to be carbonyl. It is suggested that generation of aldehyde and ketone, and carbony might occur at less than 80°C. In addition, it is indicated that the kinds of oxidation reactions were diffrent between coal X and Y.

To evaluate the effect of water and binder addition on the coal briquetting process and the strength of coal briquettes, coal briquettes were prepared, and their compressive strength was measured using a universal testing machine. As a result, the force required for briquetting process was reduced, and the compressive strength was improved with the addition of water and binder. Moreover, the observation of the internal structure of the briquette by X-ray CT clarified that the internal structure of briquette becomes dense in all additive cases compared with non-additive case. Therefore, it is suggested that the strength of briquettes is improved by the dense structure of briquettes with the addition of water and binder.

It has been reported that HCl can adsorb on Zn-doped O₂ activated carbon (AC) at 100 and 300°C. However, the effect of metals on the adsorption capability of AC and the mechanism of the adsorption stability of HCl have not yet been clarified. In this study, we used molecular orbital (RHF/6-31G*) calculations for three carbon active site models (Armchair, Zigzag, and Tip types) to investigate the effect of Zn doping on HCl adsorption via the estimation of the electronic states. As a result, the molecular models of the carbon materials with and without Zn doping showed that the presence of Zn increased the number of active sites available for the chemical adsorption of HCl molecules. Furthermore, it was confirmed that there was a good correlation between the calculation and the experimental results.

The thermal behavior of ash components in bituminous coals (Upper Freeport (UF), Illinois #6 (IL) and Beulah-Zap (BZ)) under air and argon atmospheres in the range temperature of 800-1200°C was investigated using XRD and TEM measurements. UF treated under air formed the needle-like crystals which was deduced to be mullite by transformation of andalusite because they mainly consisted of SiO₂ and Al₂O₃. In contrast to UF, IL did not generate these crystals. However, when IL was treated under air after carbonization under Ar, the crystals appeared. The presence of lime in IL inhibited the formation of mullite. Oldhamite was formed by reacting lime with sulfur at the carbonization of IL. As lime was consumed, the formation of mullite was not inhibited under air after Ar treatment.

Coal ash contains hazardous elements such as arsenic, boron, chromium, and selenium. These hazardous elements easily leach into the environment. In order to control the leaching of these elements, an aging treatment of coal ash has been recently studied. It is considered that these hazardous elements are immobilized by the generation of ettringite on the aged coal ash. However, ettringite is not stable under acidic condition. In this study, immobilization of hazardous elements, such as arsenic, boron, chromium, and selenium, by the generation of hydroxyapatite was investigated. Hydroxyapatite is stable and does not break down under acidic conditions. When an aging process was carried out under the addition of CaO and P₂O₅, hydroxyapatite was generated on the coal ash and the leaching amount of arsenic, boron, chromium, and selenium from coal ash was effectively reduced. These results suggest that hydroxyapatite contributes to the immobilization of these hazardous elements.

Adsorption of phosphorus on a denitration catalyst degrades the activity of the catalyst during long-term operation of coal-fired power plants. In order to remove phosphorus and to regenerate a spent catalyst from a real coal-fired power plant, leaching behavior with water and ammonium citrate solution was investigated and change of the catalytic activity was observed. When the catalyst was treated with ammonia citrate, 67% of phosphorus could be removed, and the activity was recovered by restoration of ammonia adsorption capacity. A part of phosphorus (29%) was removed by leaching with distilled water, whereas negligible change in activity was observed.

CO₂ methanation is expected to be an option for energy storage and supply integrated with water electrolysis using renewable energies, named power-to-gas, taking advantages of the applicability to the existing infrastructures for natural gas. There are only a few industrial-scale plants, and development of a kinetic model is essential for scaling up the methanation reactor. In this study, a kinetic model was developed for CO₂ methanation under three pressure conditions considered in industrial-scale plants. The rate coefficients were determined at each pressure and correlated with the total pressure. The derived model was applied to an estimation of a larger bench-scale reactor filled with a pelletized catalyst through one-dimensional packed bed simulations, in which the diffusion resistance caused by the use of the pellet was considered using a catalyst effectiveness factor. The kinetic model was able to reproduce the CO₂ conversion at the exit and the temperature distribution in the catalyst bed. It revealed that formation of a side product, CO was suppressed at the entire range of reactor.

As a CFRP recycling method, CFRP is pyrolyzed to separate the resin and carbon fired. In this method, it has been empirically revealed that the properties of pyrolyzed CFRP affect the next firing of residual resin process. Therefore, in this study, CFRP was pyrolyzed under various pyrolysis conditions, and the properties of pyrolyzed CFRP were evaluated. As a result, it was revealed that the pyrolysis temperature and the heating speed conditions have a great influence on the properties of the product of pyrolyzed CFRP.

To develop the energy-saving CO₂ capture from exhaust gas, we have been studying on both absorbent and process. As an absorbent, we have developed a phase separation solvent that separates into two liquid phases during CO₂ absorption, and as a process, we have developed a H₂ stripping that supplies H₂ to the desorber. We will report the results of case studies with our developed solvents and processes.

Two kinds of asphaltene molecular aggregation models (MD1 and MD2) were constructed by molecular dynamics (MD) simulation and evaluated by X-ray scattering simulation. MD1 and MD2 were constructed using model molecules determined by average molecular structure analysis and ultrahigh resolution mass spectrometry,respectively. The results of X-ray scattering simulation corresponded to the chemical structure distribution of model molecules and the aggregation models, which enabled us to directly compare them with experimental X-ray diffraction (XRD) pattern of the real asphaltene.

In this study, the gasification of bio-char was activated by using a catalyst (Fe), which is a typical alkali metal. In addition, the gasification mechanism of bio-char, on which Fe was loaded, was examined by analyzing the pore development (by measuring the specific surface area, the pore diameter) and random pore model. The results obtained in this study are as follows: (1) when Fe was loaded on bio-char, although there were closed-pores in the initial stages of gasification, pores rapidly developed with the increase in carbon conversion; (2) Rapid development of the pore diameter leads to suppress the development of the specific surface area and the gasification rate after the second half (X=0.5‐) of gasification.

Deoxygenation is necessary to obtain fuel with high calorific value from biomass. In this study, liquid fuel production with high calorific value from cedar powder (below 600μm) as the feed biomass by degradative solvent extraction using deep eutectic solvent (DES) was investigated. A mixture of choline chloride (hydrogen bond acceptor, HBA) and FeCl₃-6H₂O (hydrogen bond donor, HBD) in a molar ratio of 1:2 was mainly used as DES catalyst. By stirring cedar powder and DES in 1-methylnaphthalene solvent under nitrogen atmosphere in a autoclave at a low temperature, it was possible to extract the component dissolving in the solvent (Soluble). When the degradative solvent extraction was performed at 100, 150, and 200°C, the Soluble yields were 8, 28, and 19wt%, respectively. The Soluble yield increased with increasing the reaction time.

When the amount of cedar powder/DES was 5g/2.5g, the Soluble yield and carbon content reached 31wt% and 81wt%, respectively. In this way, it was found that the degradative solvent extraction using DES is an effective method for obtaining liquid fuel with high calorific value from biomass at low temperature.