Large-scale simulations of CO₂ gasification reaction with gas diffusion for two coke models with different porosity were conducted, and gasification reaction rate was compared between the two coke models. Although the total surface area of the coke model with high porosity was smaller than that with low porosity, the gasification reaction rate of the coke model with high porosity was larger. This is caused by the difference of the CO₂ concentration at the inner part of the coke model between the two coke models.

To investigate the factors that affect the shrinkage ratio of coke, the shrinkage behavior of coal/semi-coke during carbonization were measured by using novel equipment. Coking coal samples were heated in vessel during softening stage and were observed using a camera during shrinkage stage. It was found that coke with higher bulk density showed a low shrinkage ratio. Image analysis showed that the dense sample had a low rate of shrinkage in the early stages of shrinkage. It was suggested that the pressuring during softening of coal affects the coke shrinkage and the higher the pressure, the smaller the shrinkage ratio.

Coke is manufactured by blending more than 15 types of coal. The coke strength (DI) depends on coal blend ratio. Consequently, it is important to predict coke strength at the time to decide coal blend. The conventional prediction method of DI has been obtained by an inductive model from the average coal properties. However, this prediction has often larger error because there is no additivity in some coal properties. Therefore, we try to predict DI with AI which makes deductive model from coal blending ratio. As the result, AI prediction is more accurate than the conventional prediction for consideration of coal compatibility.

Since a large amount of NOx, that is one of air pollutants, arises from coal combustion process, the SCR method is generally applied for coal-fired power stations to reduce NOx emissions. In the SCR method, NH₃ is introduced into the flue gas at De-NOx catalyst, and NOx is reduced to N₂ by catalytic reaction. This De-NOx catalyst is located upstream of the exhaust gas treatment process, and exposed to a lot of soot and dust particles in the flue gas. Previous studies have revealed that the deterioration of De-NOx catalyst is caused by the deposition of the silica compounds on its surface. Then, the adhesion conditions of these silica compounds were experimentally clarified in this study. De-NOx catalyst samples were exposed to siloxane vapor in simulated flue gas. The formation of silica layer on the surface of De-NOx catalyst was observed by SEM/EDX. The experimental results suggested that silica layer became more explicit in gas including impurities, such as SO₂, NH₃, and NO.

The distributed Activation Energy Model (DAEM) is widely used for the analysis of pyrolysis or gasification of coal and coke. We proposed an estimation method of kinetic parameters in DAEM using a neural network. For validation, the kinetic parameters were estimated by applying the proposed method and the conventional method to the experimental data of CO₂ gasification of coke. In addition, the obtained kinetic parameters were used to predict progress on the conversion of coke, and the prediction accuracy was compared between the proposed method and the conventional method. As a result, the prediction accuracy of the proposed method was higher than that of the conventional method.

The development of pore structure of char during gasification was evaluated using TG gasification profiles and Raman spectroscopy of KZ char. The pore structure of char during CO₂ gasification reflected the initial one because CO₂ gasification proceeds on the pore surface. In contrast, the pore structure during steam gasification was developed probably owning to the growth of aromatic structures by H radicals and selective small aromatic consumption. These different mechanisms of pore structure development imply the difference of gasification reaction mechanisms.

Elution test was carried out in gypsum samples produced from a coal fired power plant, in order to understand the dissolution behavior of mercury when these materials are exposed to rain water. Experiments were carried out in 3 kinds of gypsums, two formed in liquid-column absorber desulfurization equipment and one from the jet bubbling type desulfurization equipment. For the elution test, the conventional batch method and the semi-batch method (improved method) were applied. The results revealed that the dissolution behavior of mercury varied significantly with the testing method. Furthermore, dissolution of mercury increased with decreasing pH. Quantification of mercury in eluate carried out by AAS show that in the conventional method, the dissolved mercury is then adsorbed, on the other hand, in the improved method, this behavior is negligible and only dissolution is observed.

The development of catalysts for the decomposition of biomass tar is one of the major challenges for the low-temperature gasification of biomass. In this study, Ni-loaded hydroxyapatite (HAP) catalysts were prepared for the tar decomposition at low temperature, 450°C. The effects of Ca/P in HAP on the catalytic activity of Ni/HAP catalysts for the tar decomposition were investigated because the catalytic activity of the HAP is known to vary with its Ca/P. The results indicate that the Ni-loaded HAP with higher Ca/P showed higher catalytic activity to decompose of both phenol used as a model tar and actual biomass tar.

In recent years, there is concern about the depletion of fossil fuels, so there is a demand for the production of clean carbon-neutral transportation fuels. Biomass fuel as a raw material is attracting attention because it can be considered that its use does not accompany CO₂ emissions as it grows up with the absorption of CO₂. In this study, hierarchical composite supports were prepared using microporous ZSM-5 and mesoporous Al₂O₃ and TiO₂, and then Pt, Ni, and Mo were added into the prepared composite oxides. The resultant PtNiMo catalysts were used in dehydrocyclization-cracking of soybean oil to produce aromatics and liquids fuels selectively. It was confirmed that the reaction proceeded by two routes of decarboxylation and decarbonylation at 580°C, and therefore the hydrogen consumption could be suppressed in the reaction. Pt/NM/Z(24)75Ti(600sg) produced 68 wt% of the liquid fuel fraction with C5-C18. Pt/NM/Z(24)60Ti, Pt/NM/Z(24)75Ti(500sg) and Pt/NM/Zn(18)Z(24)60Ti showed the highest CO and CO₂ selectivity of 11%. Pt/NM/Z(24)30Al30Ti and Pt/NM/Z(24)75Al(600sg) showed the highest aromatics yield of 17wt%.

Miura¹⁾ and Miura and Maki²⁾ presented a method to estimate the distribution function of activation energy and frequency factor, f(E) and k₀(E), in the so-called “Distributed Activation Energy Model (DAEM)” from 3 sets of TPR data at least. The method was reexamined and a more generalized interpretation on the method was given. It shows that E vs x_B^* and k₀ vs x_B^* relationships are natural and more general representations of the parameters of DAEM, where x_B^* is the normalized amount of solid reactant. The additional procedure was also proposed to increase the accuracy of the k₀ vs x_B^* relationship.

Solid fuel production with high calorific value from Indonesian Adaro sub-bituminous Coal (150–250μm, AC) as the raw material by degradative solvent extraction using deep eutectic solvent (DES) as catalyst was studied. A mixture of choline chloride (hydrogen bond acceptor, HBA) and FeCl₃-6H₂O (hydrogen bond donor, HBD) in a molar ratio of 1:2 was used as DES catalyst. The chemical and molecular compositions of coal were characterized by chemical analysis, Fourier transform infrared spectrophotometer (FT-IR), gas chromatography, and thermogravimetric analysis (TG). By stirring AC in 1-methylnaphthalene solvent under nitrogen atmosphere in an autoclave at 350°C, it was possible to extract only 22wt% of the component dissolving in the solvent (Soluble). On the other hand, when the degradative solvent extraction using DES was performed at 200, 300, and 350°C, the Soluble yields were 11, 38, and 69wt%, respectively. When 5g of raw material and 2g of DES were used, the Soluble yield and carbon content reached 69wt% and 89wt%, respectively. In this way, it was found that the degradative solvent extraction using DES is an effective method for obtaining solid fuel with high calorific value from low-rank coal.

It is necessary to establish carbon recycling technology toward the realization of carbon neutrality. In our laboratory, we have focused on the decomposition and reduction ability of atmospheric pressure plasma and have been developing plasma devices for CO₂ decomposition and reduction. Results so far has reported particles containing carbon are deposited on the electrode surface inside the reactor after treating CO₂ with atmospheric pressure plasma. The purpose of this journal is to investigate the generation behavior of plasma jets and to analyze the generated carbon-containing particles by CO₂ plasma jets. A metal plate was irradiated with this CO₂ plasma jet, and the surface of the metal plate was observed and analyzed by SEM-EDX. As a result, trace amounts of carbon-containing particles have been confirmed on the surface of the metal plate. In other words, we have succeeded in producing carbon-containing particles outside of the reactor.

Since IGCC can generate electricity at a higher efficiency than the conventional pulverized coal combustion method, the use of various types of coal is being considered. However, when the coal properties change, the emission characteristics of trace elements also change, but it is difficult to adapt to them each time. Therefore, a system that can predict the emission characteristics of trace elements from coal properties is eagerly awaited. In this study, a prediction method based on thermodynamic equilibrium calculation was developed to predict the behavior of trace elements in the gasifier from coal properties and feed rate data. From the calculation results of the prediction method, it was found that four trace elements (As, Cl, Se, and Hg) formed gaseous compounds in the gasifier, and it was predicted that these trace elements would not be recovered as slag.

In the present study, mineral liberation characteristics of each diameter range were estimated by sieving and sink-float separation. The results show that the ash formed at a low temperature is suitable for ash property analysis of coal because the clay and carbonate minerals alter at a high temperature. It was found that the sieving could be used to narrow down the coal diameter range of high ash content and high ash mass distribution. Therefore, efficient demineralization seems to be achieved by classifying the coal diameter range with high ash mass using physical properties with large differences between ash and combustible contents such as the specific gravity.

In this study we prepared porous carbon samples from various carbonaceous materials, such as biomass and coal, and evaluated their CO₂ adsorption performance. First, activated carbons were prepared by heat treatment of a mixture of melamine as a nitrogen source and K₂CO₃ as a chemical activator added to the carbonaceous resource, and their pore properties were investigated in detail. Then, the CO₂ adsorption performance of the prepared activated carbons was tested. It was found that activated carbon with well-developed pores could be prepared by using carbonaceous resources with low carbon and low ash contents. The specific surface area (SAA), micropore volume and CO₂ adsorption of the prepared activated carbon showed relatively good correlation. In other words, we found that the SAA and micropore volume affected the CO₂ adsorption performance. Additionally, the optimum micropore diameter for CO₂ adsorption was identified as 0.7–1.0nm.

The measurement techniques for carbon aromaticity and average side chain length, the parameters for an average molecular structure analysis, were examined from Infrared spectra. Carbon aromaticity can be estimated from the spectrum range of 1300-1800cm^-1 and H/C atomic ratio with an average error about ±7%. The average side chain length can be estimated from the range of 2600-3000cm^-1 with an average error about ± 50%. Although the average errors are not enough for the average molecular structure analysis, the results are helpful to limit the ranges of parameters.

A conventional method was improved to the determination of carbonyl groups (C=O) in solid sample using infrared spectrometry. The factors were determined with carbonyl peaks of acetophenone, cyclohexanone, benzoic acid and heptanoic acid against the peak at 2120cm^-1 of 1-tetradecyn, which was an internal standard (IS). The factors were valid less than 0.8 of C=O/IS molecular ratio. In addition, dichloromethane was useful to prepare a solid sample/IS slurry for the measurement with small sample size.

To characterize chemical structure of oxidized coal, solid state ¹³C MAS NMR spectra were acquired for bituminous coal with lower water contained (=low moisture) and with higher water contained (=high moisture) before and after estimation of their self-heating property using R70 apparatus. It was found that low moisture coal reached 80°C in shorter time than high moisture one. The chemical structural change in low moisture coal during oxidation was found to be increasing aldehyde, ketone and carbonyl, while that in high moisture one was found to be decreasing aldehyde and ketone. It is suggested that the dominant chemical reaction which induces self-heating of coal depends on the amount of water contained in coal before oxidation.

Asphaltene aggregation analyses by Rayleigh scattering and small-angle X-ray scattering (SAXS) were compared to examine the relationships among the degree of asphaltene aggregation (D_agg), the radius of gyration (R_g, nm), and the molecular weight of aggregates (Mw). We used two kinds of asphaltenes at 20-50000mg/L in toluene or toluene/pentane mixed solvent (10 vol% of pentane) at room temperature. The results clarified the relationships of R_g = 1.4D_agg – 1.4 and Mw = 4488R_g^1.7.

We have developed Micro-Filler-Compound Technology. We also developed unique Twin Screw Extruder and unique Screw Paddle, as a dynamic compounding reactor. This technology allows easy compounding, such as Fly-Ash and Recycled Polymers, with the addition of Liquid Solvent. The Liquid Solvent works as a reacting agent along with vaporizing at several compounding steps.

FA-Bord is World’ First Fly-ash Reinforced Plastic Bord that is SDGs compatible products for construction and housing area. One of the most unique properties is Sink under Water that shall be applied flood damaged area. We are under marketing FA-Board-ECO now for this application.

In this study, the thermal behavior of ash components in three types of Vietnam coals, anthracite (Quang Ninh, QN), bituminous coal (Thai Nguyen, TN), and lignite (Lang Son, LS), were analyzed by XRD and TEMs. In order to obtain ash components, these coals were calcined in air or Ar atmosphere at different temperatures. From the analysis of QN ash, the peak of anhydrite was observed by XRD measurement even though the CaO content of the ash was very low, suggesting that anhydrite is a mineral that easily crystallizes. From the results of XRD measurements of QN and LS, it was found that calcination in an air atmosphere causes a change from kaolinite to andalusite to mullite. From the results of XRD measurement and TEM observation, the needle-shaped crystals observed by QN and LS calcined at 800°C and 1000°C in an air atmosphere may be andalusite. It was found that crystal ash components in Vietnam coal behave differently depending on the processing temperature and atmosphere.

Fly ash from pulverized coal-fired boilers are used as a raw material for concrete. However, it is known that the unburned carbon in fly ash affect concrete quality. In this study, we investigated a prediction method of the unburned carbon content with EA/IRMS which could measure stable carbon isotope ratio (𝛿¹³C) in raw coals. As a result, the unburned carbon content can be predicted from the value of “Factor of 𝛿¹³C”, “H/C atm%”, “Inert ratio”, and “Fuel ratio”, with the error of 0.6wt% or less.

The Osaki CoolGen Project aiming to realize the revolutionary low carbon coal fired power generation has conducted the project subsidized by the Ministry of Economy, Trade and Industry (METI) since FY2012 and the New Energy and industrial Technology Development Organization (NEDO) since FY2016. In this presentation, we introduce summary of Osaki CoolGen Project and progress of oxygen-blown IGCC with CO₂ capture demonstration.

Integrated coal gasification combined cycle (IGCC) has the advantage of high coal type compatibility compared to conventional pulverized coal-fired power generation, and high-power generation efficiency can be obtained even when low-grade coal is used. However, the use of a wide variety of coals generates slag with different melting points (RFT), which may cause pipe blockage. To prevent this problem, we attempted to predict the RFT in advance using machine learning. As a result of predicting the RFT from the coal property values, we obtained the result that the prediction was possible with an RMSE of 26.74°C (prediction error of 2.1%).

The simulation was conducted to predict the concentration of nitrogen oxides (NOx) generated by pulverized coal combustion with accuracy and simplicity. In this study, the chemical reaction analysis software ANSYS CHEMKIN 2019 R3 was used to simulate a turbulent reactor. A reactor network model of a turbulent reactor was studied, and the effect of Volatile N, which contributes significantly to NO production, was also investigated. As a result, we were able to roughly reproduce the NO production behavior. It was also found that the behavior was greatly affected by the configuration of the reactor model, such as the distribution of air and Volatile N. In order to predict NOx production more accurately, it is necessary to establish a method for constructing a reactor network model and to study the reaction rate parameters.

In order to investigate and reduce the formation of fine particles generated during the combustion process of fuels mixed with a high percentage of woody biomass fuels, a drop tube furnace was used in this study. Two types of coal were prepared by adding 5, 15 or 30% of two types of woody biomass, and the formation behavior of fine particles (PM_0.1, PM_0.5, PM_2.5, and PM₁₀) was investigated. The results showed that, depending on the combination of coal fuel and biomass fuel, the addition of biomass fuel did not increase the emission of PM_0.5 and PM₁₀ in some cases compared to the case where only coal was burned. This result is an interesting finding that the addition of biomass can reduce the amount of fine fly ash generated and reduce the heat transfer inhibitors such as slag and fouling in the boiler.

Coal still has important roles for stable and economical power generation, although CO₂ emission needs to be decreased. CRIEPI has developed a high efficiency oxy-fuel IGCC system. The oxy-fuel IGCC system consists of an O₂/CO₂/H₂O blown gasifier, dry gas clean-up process and semi closed cycle gas turbine system. The system can keep thermal efficiency more than 42%_HHV even after capturing CO₂. The fundamental development of each unit was successfully completed by FY 2020. On the other hand, currently, adjustment ability of supply and demand is required to respond to variable renewable energy power generations. Therefore, the authors proposed an advanced polygeneration system with CO₂ capture. A main unit of the system is the O₂/CO₂/H₂O blown gasifier developed in the above project. In addition, the gasifier is applied to use carbon-based wastes and biomass as well as coal, to decrease CO₂ emission. Furthermore, the system produces both power and valuables to increase the supply and demand adjustment ability.

Central Research Institute of Electric Power Industry is developing a polygeneration system with CO₂ capture consisting of an O₂/CO₂/H₂O blown gasifier that uses various fuels such as coal, waste plastic and biomass. We investigated the effect of adding plastic to coal on gasification performance experimentally using 3t/d coal research gasifier. It was confirmed that gasifier carbon conversion efficiency increased and cold gas efficiency nearly unchanged under the same oxygen ratio. It is considered that cold gas efficiency can be improved by adjusting the oxygen ratio. And it was found that the char of 1 µm or less increases due to the increase in volatile matter in the fuel.

Solid oxide fuel cells (SOFCs) are expected to be applied to Integrated Coal Gasification Fuel Cell Combined Cycle (IGFC). However, most SOFC modules are designed for natural gas as fuel.

In this research the power generation performance of H₂ rich gas, which is simulated gas as CO₂ separation coal gas, was verified. As a result, it was confirmed that the output of SOFC modules was reduced than natural gas. On the other hand, improvement of SOFC performance by using H₂ rich gas was possible by adjusting the operation parameters.

In the case of real IGFC with CO₂ separation and capture systems, amount of trace CO₂ may remain in the coal gas that is supplied to SOFC. The same parameter tests were also carried out by using simulated coal gas, which is adjusted to IGFC gas compositions. As a result, the power output was increased. The gasifier connecting facilities, which consist of removing the toxic substance for SOFC were designed and were build for real coal gas tests. It was confirmed that they worked effectively.

Dry syngas purification process is capable to realize co-production of power and valuable chemical at low emission of carbon dioxide. Sulfur removal with regenerable sorbent is key technology to configure the process. The sorbent is used in desulfurization cycle which repeatedly conduct removal and release of sulfur compounds. It is essential to adjust operation time for removal and release to operate the process continuously. Multicycle test of zinc ferrite sorbent was performed to investigate effect of gas supplying condition to the sulfur release characteristic. Both gas flow rate and oxygen concentration can control duration for the sulfur release trend. This finding can be used to provide potential procedure to adjust schedule of sulfur removal and release during the cyclic operation of the sulfur removal process.

There is a limit to the production of CO₂-free hydrogen with renewable energy, and CO₂-free hydrogen derived from fossil fuels is required for stable production in large quantities.

Half of the coal that is endowed in the world is brown coal, and there is a huge amount in Victoria, Australia.

Brown coal is a low-quality coal with a low degree of coalification and a large amount of water and impurities, but by using it as a raw material for hydrogen, which is the next-generation energy, it can be used for effective use of resources and reduction of CO₂ emissions.

Chromated copper arsenate–treated wood produced by injecting a solution containing sub–percent of chromium, copper, and arsenic (hereinafter referred to as CCA–treated wood) is one of the construction wastes. As fundamental research on the development of clean gasification process for biomass, pyrolysis (400–800°C) which is the initial stage of gasification and CO₂ gasification (1000°C, 0–60min) characteristics of CCA–treated wood were investigated. The release behavior of high volatile arsenic during pyrolysis and gasification of CCA–treated wood was followed. When the CCA–treated wood was pyrolyzed, the release of arsenic proceeded with increasing temperature and the release extent was 41% at 800°C. In the case of gasification, the release extent of arsenic increased with gasification time and 90% of the arsenic was released into gas phase within 60min. Furthermore, it was possible to suppress the release of arsenic by 800°C during pyrolysis by mixing organic sludge rich in iron and calcium with CCA–treated wood.

Integrated coal gasification combined cycle (IGCC) has high thermal efficiency and can make a significant contribution to reduce CO₂ emissions. Among them, Oxy-fuel IGCC with CO₂ capture, which is currently under development, can dramatically reduce CO₂ emissions with keeping high thermal efficiency. One of the main components in IGCC is a coal gasifier, and it is important to gasify solid carbon resources efficiently in a gasifier. Especially, since soot is less reactive than char, prediction of its production is important for accurate prediction of the gasifier performance. In order to predict the amount of soot production, a numerical analysis combined with a reduced chemical mechanism and CFD was performed for a gasifier. As a result, the prospect that the soot formation in a gasifier can be predicted by numerical analysis can be obtained.

Gaseous elemental mercury (Hg⁰) removal test using copper-based sorbent that is coated with copper oxide (CuO) on surface of the honeycomb-shaped support was performed in O₂/CO₂ blown coal gasification gas. The sorbent piece with 3×3 cell structure was subjected to the removal test in a fixed bed reactor introducing actual syngas from coal. Gas analyses were performed by a gas chromatography and a Fourier-transform infrared spectroscopy during the test. Quantitative analysis and X-ray absorption fine structure (XAFS) measurement of the fresh and the spent sorbents were also performed. Copper oxide in the sorbent reacted with hydrogen sulfide (H₂S) to form copper sulfide (Cu₂S, CuS). The sulfurized sorbent removed Hg⁰ from actual coal syngas at around 130°C, 1.9MPaG. These results revealed that the copper-based sorbent is a potential candidate for the dry mercury removal process in gasification gas.