In response to the need for a low-carbon society, the steel manufacturing industry, which is a major producer of carbon dioxide, has introduced hydrogen to replace some fossil fuels. Since the degradation behavior of coke is one of the factors that deteriorate the efficiency of the blast furnace, it is important to understand the degradation behavior of coke during the H₂O gasification process at hydrogen enriched blast furnace. In this study, to find the effect of temperature on degradation behavior between CO₂ gasification and H₂O gasification, gasification experiments were conducted in CO₂ and H₂O atmospheres at different temperatures in 20% conversion ratio. Moreover, to investigate the pore behavior, we used the SEM to observe the cross-section of cokes.

CRIEPI is developing the poly-generation system with entrained-flow gasifier. In this system, we expect to utilize plastic wastes as fuels in addition to coal. In our previous study, it was found that the aromatic rings of soot were developed by adding refuse derived paper and plastics densified fuel (RPF) to coal during the pyrolysis at 1400°C. In this study, another plastic sample (polypropylene, PP) which had no oxygen contents was added to coal. Char, soot, and gas yields and the aromatic rings of soot were analyzed during pyrolysis and CO₂ gasification. Soot yield during co-pyrolysis and co-gasification of coal and PP was higher than RPF, which was caused by the less oxygen contents. The development of the aromatic rings induced by the hydrogen abstraction C₂H₂ addition (HACA) mechanism was inhibited by the consumption of plastic volatile matters with the oxygen contents of plastics and gasifying agents.

The electrochemical CO₂ reduction reaction (eCO₂RR) offers a sustainable method for reducing greenhouse gas emissions by converting CO₂ into valuable chemicals and fuels without requiring extreme conditions. Electrocatalysts play a significant role in this process by producing carbon-based products such as ethylene, etc. Perovskite oxides have emerged as promising electrocatalysts due to their high ionic/electronic structure, stability, ability to vary elements, and the alkaline earth effect, which enhances the *CO₂ - intermediate. Specifically, Ca is the A-site in coordination with the Cu-site, providing Ca₂CuO₃ with strong basic strength and exceptional CO₂ adsorption capabilities. The Ca₂CuO₃ catalyst demonstrates significant efficiency in converting CO₂ to C₂H₄, exceeding FEC₂H₄ 50% at 100 mA/cm^₂. This research represents an attractive advancement in realizing the conversion of CO₂ to C₂H₄.

CO₂ methanation is performed at 300-450°C and atmospheric pressure using Ni supported on CeO₂ or ZrO₂ as catalysts with moderate basicity. However, the cost of the catalyst is problematic. Therefore, the perovskite-type oxides, BaZr_0.95M_0.05O_3-δ, in which a part of Zr⁴⁺ is replaced by M³⁺ (Y, Fe, Al) and oxygen vacancies were increased, were focused on. In this study, the effect of Ni 10 wt% supported perovskite oxide catalysts on CO₂ methanation reaction at 300-450°C was investigated. The highest CH₄ yields for Ni/BaZrO₃ (400°C), Ni/BaZr_0.95Y_0.05O_3-δ (350°C), Ni/BaZr_0.95Fe_0.05O_3-δ and Ni/BaZr_0.95Al_0.05O_3-δ (400°C) were 65, 75, 72 and 56 mol%, respectively. From the CO₂-TPD profiles, CO₂ desorption amounts of Ni/BaZr_0.95Y_0.05O_3-δ and Ni/BaZr_0.95Fe_0.05O_3-δ increased more than that of Ni/BaZrO₃ between 100‒500°C, whereas Ni/BaZr_0.95Al_0.05O_3-δ decreased 250‒400°C, indicating that the sites with moderate basicity for Ni/BaZr_0.95Y_0.05O_3-δ and Ni/BaZr_0.95Fe_0.05O_3-δ increased by the formation of the oxygen vacancies.

To prepare humic acid from biomass (sugarcane leaves) with high yield, a two-step hydrothermal treatment using acidic and alkaline solutions was carried out. It was confirmed that when the biomass was treated directly with hot alkaline solution, the yield of humic acid was only 5% of the total carbon. Since humic acid can be obtained in high yields when reagent lignin is treated with hot alkaline solution, it was speculated that cellulose and hemicellulose in the biomass inhibit the alkaline extraction of lignin. To decompose cellulose and hemicellulose, the biomass was hydrothermally treated in an acidic solution at different temperatures and reaction times, and the obtained sample was then treated in an alkaline solution to recover humic acid. At 140°C, that hemicellulose decomposes, the humic acid yield increased to approximately 8%. It was found that by increasing the temperature to 180°C and extending the reaction time, the cellulose was decomposed and the humic acid yield increased to 15%.

Iron-based materials have been attracted as cathode material for large-scale lithium-ion batteries because iron resources are more abundant than those of cobalt and nickel. Lithium iron phosphate (LiFePO₄) shows excellent thermal stability, so, it is used in EV’s battery and stationary battery. However, its disadvantage is low electronic conductivity. To overcome this problem, carbon coating techniques have been studied. In this paper, we studied carbon coating on the surface of lithium iron phosphate using Soluble extracted from rice husk. Carbon-coated LiFePO₄ (LiFePO₄/C) was obtained by calcination of the mixture of LiFePO₄ and Soluble in Ar atmosphere. The charge and discharge characteristic of LiFePO₄/C was evaluated, and it showed higher charge/discharge capacity than that of LFP at current rates of 5C and 10C. The electronic conductivity of LiFePO₄ was successfully improved by carbon coating using Soluble.

Efficient conversion of biomass-derived furfural into high value-added chemicals such as tetrahydrofurfuryl alcohol (THFA) by hydrogenation has received much attention in terms of post-fossil fuel and energy saving. While many researchers have put their efforts on developing cost-effective catalysts for furfural hydrogeneration, only little investigations have been reported on its techno-economic analysis as well as process optimization. This study aims to design an energy saving process model of furfural hydrogeneration for THFA synthesis coupled with thermal recovery system consisting of organic Rankine cycle and heat pump, and to evaluate energy efficiency and economics of the proposed process through Aspen simulation, based on our previous experimental data with Ni1Cu1-Al1 catalyst.

To investigate the effect of the coal fluidity on the strength of the coke made by a sequence of pulverization, hot briquetting and carbonization, the strength of coke produced from the 5 different coals with the common logarithm of the maximum fluidity (logMF) ranging from 0 to 1.61 was measured. With the increase in MF, the coke strength increased and reached a maximum peak at logMF=0.78, then decreased significantly. Based on the scanning electron microscopic observation, the coke produced from the coal with logMF=0.78 had a dense structure in comparison to the coke made from the coal with logMF=1.52. The porous structure of the coke made from the coal with logMF=1.52 was estimated to be due to the excessive foaming during the coal plasticity.

Gas from a plastic layer generates coking pressure to the coke oven wall during the dry distillation of coal in a coke oven. The coking pressure can damage the coke oven when it is excessive, hence it is important to evaluate and control the coking pressure. Coking pressures of various coals were measured and the relationship between coal properties and coking pressures were investigated which have not been elucidate so far precisely. As a result, it was found that each coal, which has different properties, could be classified into clusters corresponding to different coking pressures. A certain coking pressure and it corresponding coal properties can be estimated by machine learning which can predict appropriate cluster.

Raw materials for pitch-based carbon fiber were derived from coal and petroleum. These raw materials and the carbon fiber precursors prepared from the raw materials are complex mixtures of heavy hydrocarbons. Average molecular structure analysis of the raw materials and the precursors is important to develop high-quality carbon fibers. In this study, we investigated the changes in molecular structure during the preparation of precursors and the differences between the coal-based and petroleum-based precursors.

Biomass generally contains higher potassium and chlorine, compared with coal. Therefore, gaseous KCl generated during combustion adheres on heat transfer tubes due to condensation. However, KCl within ash deposit concentrates at the interface between tube surface and ash deposit layer in Circulating Fluidized Bed (CFB) and/or conventional boilers. In this study, the experiments on KCl condensation, using a compressed ash pellet, showed the feasibility that gaseous KCl penetrated inside the ash deposit and condensed at the surface of heat transfer tubes. Additionally, the effects of S, Si and Ca on Cl deposit were also discussed by lab-scale ash-deposition experiments, using eight samples of coal and biomass fuels. The experimental results showed that both S and Si could reduce Cl condensation, while Ca promoted the Cl deposit on the heat transfer tubes.

Some of the ash generated during the combustion of pulverized coal can adhere to the surfaces of heat transfer tubes, inhibiting heat transfer and causing operational issues in boilers. In this study, combustion experiments were conducted using a laboratory-scale drop tube furnace (DTF), where two types of coal (CV coal and TOP coal) were mixed with biomass samples of black pine pellets (KP) and black pellets (BP). The collected combustion ash was classified by shape using deep learning, and compositional analysis for each shape was performed using SEM-EDS. The analysis identified characteristic features of each shape and confirmed the presence of biomass-derived combustion ash particles.

In this study, we investigated the melting properties and the shape of combustion ash which was collected in the actual PC boiler to improve the accuracy of ash-deposition evaluation. As a result, it was found that the ash components of early-stage deposition existed as a molten state during combustion. And the melting properties of the combustion ash were considered to change significantly at 1200 to 1300°C due to the influence of calcium and iron. Furthermore, the result of the classification of ash particle shape indicated that the factors of ash-deposition were different in the combustion conditions. In addition, considering the gas temperature and the formation of particles larger than 10 μm, the formation and loss of clinker in the boiler operating conditions can be summarized.

The coal ash of Quang Ninh (QN) coal contains a large amount of Al₂O₃ and SiO₂. In this study, we examined the effects of components contained in actual QN coal ash but not required for the preparation of zeolite on the preparation of zeolite and the catalytic cracking reaction. At 165°C and 96h, slight crystals were seen even at a SiO₂/Al₂O₃ ratio of 6.5, and as the SiO₂/Al₂O₃ ratio increased, the crystals grew. The intensity of XRD signals at SiO₂/Al₂O₃ ratio of 26 approached that of commercial ZSM-5 with SiO₂/Al₂O₃ ratio of 24. At SiO₂/Al₂O₃ ratio of 39, the intensity of XRD signals was higher than that of commercial ZSM-5. When these catalysts were tested in the catalytic cracking of LDPE, conversions of LDPE decreased in comparison with that of conventional ZSM-5 probably because coal ash included large amounts of alkali and alkaline earth metals which neutralized acid sites of zeolite.

To develop a low-cost hydrogen chloride (HCl) removal process from syngas, removal characteristics of HCl using commercially available calcium hydroxide sorbent (CHS) were evaluated. The CHS was set into a quartz reactor of lab-scale fixed-bed test apparatus, and the simulated coal and waste plastic gasification gas containing 400-2000ppm HCl was fed into the reactor for a certain period. The results of gas analysis using a Fourier transform infrared (FT-IR) spectrophotometer showed that the CHS was able to reduce HCl to less than a few ppm. Elemental analysis and XRD analysis of the tested CHS revealed that the Ca in CHS reacted with HCl to produce CaClOH, and reacted with CO₂ to produce CaCO₃. In the temperature range of 250～450°C, CHS reacted better with HCl at lower temperatures. A low-cost two-stage halide removal system could be constructed by providing a small-scale high-performance sorbent such as sodium aluminate reactor as a backup process downstream of the CHS reactor.

CRIEPI is developing a poly-generation system using various fuels with CO₂ capture. The system consists of O₂/CO₂/H₂O blown gasifier, a gas clean-up, a power generation, and a chemical synthesis process. Various carbonaceous feedstocks, such as plastic wastes as well as coal are fed into the gasifier. This presentation shows the current progress of the research project, particularly the reductor simulating gasifier test results. The “reductor” is the upper part of the two-stage entrained-flow gasifier, while the lower part is the “combustor”. The gas composition and temperature in the combustor of the reductor simulating gasifier is controlled by gas feeding ratio without feeding solids into the combustor. This allows for a detailed investigation of the gasification products, char, soot, tar and gas generation behaviors in the reductor condition. In this study, coal and polypropylene (PP) as a plastic-waste simulated sample were co-gasified. By PP addition, char decreased while soot and tar increased. Higher temperature reduced char, soot and tar. Furthermore, H₂O concentration in the combustor had a complex effect on the products in the reductor.

Since aromatic tar is produced from coal and aliphatic tar from plastics in pyrolysis, a large number of chemical species and chemical reactions must be considered to evaluate tar and soot in co-gasification of coal and plastics. To overcome this issue, this study developed a reduced reaction model that treats tar and soot as hypothetical chemical species and considers these reactions in the global reaction model. Using the developed reaction model, CFD simulation of a gasifier, called reductor simulating gasifier, was performed. The results showed that tar is produced by pyrolysis and then consumed by chemical reactions. Soot is formed from tar and then consumed by gasification reaction, but it remains until the outlet of the gas-fired furnace compared to tar. The developed reaction model can be used to evaluate the behavior of tar and soot in co-gasification of coal and plastics.

Oxygen-blown ICC is one of the power generation technologies that can achieve both power generation and CO₂ capture with high efficiency. In order to improve this operability, we have developed a thermal and material balance model that can predict the gasification characteristics of coal and biomass suitable for oxygen-blown gasifiers. The accuracy of the char generation prediction formula was confirmed by applying three types of char generation prediction formulas to this model and comparing them with the operation data of a small gasifier (10t/day) and a large gasifier (150t/day).

In the reaction of Y coal with ¹⁷O₂, the total amount of gas produced increased as the reaction temperature increased. The gas evolved was mainly isotope-free gas generated by the decomposition of oxygen functional groups in the coal. However, gas containing isotopic oxygen was also observed at 40°C, indicating that gas generation occurred via an oxidation reaction with ambient gas. More gas generation was observed in the untreated Y charcoal with moisture, but the ratio of oxygen-free CO₂ gas generation was higher.

On the other hand, dry Y coals with faster exothermic rates had a higher ratio of C¹⁶O¹⁷O.

To elucidate the mechanism of chlorine (Cl) enrichment in oxygen-blown gasification chars, the chemical forms of Cl on the gasification chars collected from actual equipment and the reactivity of the chars with gaseous HCl were investigated. It was found that Cl exists as both of inorganic and organic forms on the surface of the char by XPS and XRD analyses. When as-received chars were treated with water, Cl, Na, and K contents were greatly reduced. HCl treatment of each char showed that the behavior of HCl concentration at the reactor outlet depended on the treatment temperature. In addition, the recovery rate of HCl concentration at the reactor outlet tended to be higher for the water-treated chars compared to the as-received chars.

In a blast furnace, powder is generated by applying force to deteriorated coke as the gasification reaction progresses. In this study, a medical X-ray computerized tomography was used to photograph coke before and after the gasification reaction and after strength measurement under CRI and CSR conditions. Then, three-dimensional image analysis was used to visualize the same cross-sectional images before and after the reaction and after strength measurement. Using the above method, the relationship between the gasification reaction region of coke and its size degradation behavior at I-type rotational strength was investigated.

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 or more TPR data sets. In this presentation a graphical method that is equivalent to the Miura-Maki method is presented. The method, which may be called “Pseudo Master Curve Analysis”, can be a general method to analyze not only infinite number of parallel firstorder reactions but single reactions. The method was developed based on a new finding using a general basic equation.

The graphical method was proposed to analyze infinite number of parallel first-order reactions in 2-08. This paper examines how the graphical method works for analyzing not only infinite number of reactions but single reactions. It is shown that there are many sets of E(x*) vs x* and k₀(x*) vs x* relationships that fit x vs T relationships for a selected heating rate. Constant E approximation as well as constant k₀ approximation, for example, work when heating rate is fixed. The method is powerful to judge if the unknown reaction is represented by single reaction. It is also powerful to evaluate the accuracy of experimental data. Thus, the generality and usefulness of the proposed graphical method were clarified.

From our previous studies, we found that the addition of Au to CuCeO₂ZrO₂ composite catalysts prepared by the sol-gel method showed the remarkable increase in the activity of the CO₂ reforming reaction of ethanol. In the present study, we aimed to further improve the activity by modifying CuCeO₂ZrO₂ composite catalysts with Ag addition. AgCuCeO₂ZrO₂ composite catalyst improved the ethanol conversion, and the yields of H₂ and CO were maximized for the 2Ag8Cu67.5Ce22.5Zr catalyst. TG-DTA measurements of the catalysts after the reaction suggested that Cu metal species of the active catalyst would be less susceptible to oxidation, facilitating the transfer of oxygen to the carbonaceous species to produce CO. However, AgCuCeO₂ZrO₂ catalysts exhibited the larger amount of coke formation than previous AuCuCeO₂ZrO₂ and CuCeO₂ZrO₂ catalysts.

When kelp, a marine biomass, was carbonized, it was found that numerous fine pores were formed, creating a porous carbon material similar to activated carbon. Analysis of the gas components generated during heating and the carbonized material after heating revealed that kelp and wakame have different carbide structures, which helped clarify the mechanism of activated carbon production. It was also suggested that the salts contained in seaweed may influence the changes in molecular structure during the carbonization process.

Some ash particles in municipal and industrial waste adhere to heat exchanger tube surfaces, which causes problems such as heat-transfer inhibition, high temperature corrosion and low utilization in Waste-to-Energy (WtE) plants. The objective of this study is to develop new surface treatment materials and techniques which can decrease the ash deposition and corrosion. In this paper, the effects of the new material developed were verified on site. The results of the test show that the new material decreased ash deposition and high-temperature corrosion due to molten salts compared to SUS310S.