To date, we have focused on the utilization food waste that has low recycle rate, namely the use of food waste as fuel for steelmaking slag-used sediment microbial fuel cells (SS-SMFC). In this study, we aimed to propose the structure of anode chamber of SS-SMFC using food waste, which can produce high performance of electricity power generation. Based on the experimental results, the anode structure of SS-SMFC using food waste was established for practical use. However, the water quality of the cathode chamber deteriorated with time passing, and the power generation performance decreased after 6 days in the case of our experimental scale. In the future, it is necessary to consider the structure of the cathode chamber that can maintain the power generation or a method that can prevent the deterioration of the water quality.

In recent years, efforts to utilise the Black Soldier Fly (Hermetia illucens), which can efficiently digest and decompose unutilised resources, are progressing, and there are high expectations for new resource recycling and its operation. The project has developed into the following. In Japan, too, the Insect Business R&D Platform has created guidelines for producing American burying beetles and, together with compliant companies, has launched initiatives that contribute to a new resource cycle. On the other hand, mechanisms to protect a sustainable production environment for insect production are inadequate. This study aims to establish evaluation criteria for adequate circulation of unutilised resources and works to maximise insect functions. This country has a ministerial ordinance to strengthen and thoroughly implement measures to ensure feed safety using recycled food resources (eco feed). These guidelines are among the best in the world for ensuring safety in using unused resources. The European Commission for Food Safety and Hygiene defines insects as novel food but ensures safety in its production guidelines. Since a wide variety of insects may be distributed in this country, the importance of efforts to establish inspection items and systems for safe operation, such as livestock feed or human food, will be discussed.

There have been many reports of microbial community structure analysis from organic waste treatment facilities and isolated cultures of microorganisms from waste treatment facilities. However, there are few reports on detailed comparative analysis of the microbial community information from organic waste treatment facilities and that from laboratory liquid culture of organic waste treatment facility-derived samples.

The purpose of this report is to clarify the distribution of microorganisms between in situ and in vitro by conducting a comparative analysis of the microflora living in the actual on-site environment and the microflora grown in liquid culture in the laboratory.

Rice husk is a by-product of rice production and is a biomass resource that does not compete with food. However, while some of the rice husks are used as compost and bedding for livestock barns, most of the rest is disposed of as waste. In this study, we investigated the effects of the activation treatment of rice husk charcoal on the pore structure, aiming at the production of highly functional activated carbon from rice husks.

Though, the yield of activated carbon obtained by activation at 750-950°C decreased as the activation temperature increased, the micropores developed more and the specific surface area increased. Furthermore, it was found that the higher the activation temperature, the more mesopores were formed.

The supply rate of apartment has exceeded 60% in Korea, but there are various chronic problems in recycling of food waste in apartment. Referred to the food waste disposer system for newly built aparment in Japan, the collection and resource recovery system of food waste in apartment was developed.

Joint collection and solid recovery system of food waste in apartment were developed for high quality of solid recycling in apartment. The quality characteristics test results of all recycling methods were highly satisfied.

This study estimated the recovery potential of nitrogen (N) and phosphorus (P) contained in different types of biomass waste (food waste, sewage sludge, manure waste) in Japan under the assumption of recycling total biomass waste through composting and anaerobic digestion. Indirect and direct GHG emissions generated from the recycling process, excluding transportation, were also estimated. Firstly, the N and P flow and GHG emission from the current solid waste management system was calculated. About 90% of N and P were reduced to N₂ and stocked in the landfill after incineration. Under the assumption of recycling, the recovered amount of N and P from the codigestion of food waste and sewage sludge through anaerobic digestion was about five times higher than the current situation, with 20% less GHG emission. The recovered N and P from manure waste treatment were already enough for the amount of chemical fertilizer demand but showed a 200% of a significant reduction in GHG emissions in the scenario of anaerobic digestion. Further consideration of regional properties in appropriate treatment and GHG emissions from transportation is required.

Currently, the earth is facing problems such as resource depletion and global warming. One way to solve these problems is to centrally manage and utilize a series of processes from product manufacturing, consumption, waste discharge/collection, intermediate treatment, recycling, and final disposal on a platform to process waste. and optimization of resource recycling. This study clarifies the relationship between the retail sales volume, which is the artery of this platform, and the general waste volume, which is the vein, and predicts the waste discharge volume using retail sales data.

In this study, V was recovered from VTM(Vanadium titano-magnetite) minerals through CaO roasting and hydrometallurgy process. The CaO roasting process transforms the phases of Fe₃O₄ and FeTiO₃ into CaFeO_x and CaTiO₃, respectively, and particularly facilitates the leaching of V. 10 wt% of CaO was mixed with VTM minerals and roasted for 3 hours at 1150 °C in an air atmosphere, and the roasted product was subjected to leaching process by sulfuric acid. As a result of leaching, 86% of V was leached by reacting for 6 hours at 1M sulfuric acid, 70℃, and 10% solid-liquid ratio, and at this time, the leaching efficiency of iron and titanium was 10%. A solvent extraction process was used to selectively separate V from iron and Ti by Alamine 336 as an extractant. Extraction was performed according to the concentration of Alamine 336 and the acidification rate. 80% of V was selectively extracted from Fe and Ti through 30% acidified 0.7M Alamine 336 and O/A ratio 1 through 3 stage countercurrent extraction. The recovered V is expected to be applied to industries related to vanadium redox flow batteries(VRFB) or energy storage system(ESS).

This study elucidates the phenomenon of a novel approach utilizing swelling of cables and subsequent ball milling of swollen cables to recover high-purity Cu and PVC from waste wire harness cables. The proposed method eliminates the need for complex post-recovery techniques such as electrostatic separation, highlighting not only the 100% recovery and purity but also the unique advantages of ball milling in this context.

Coal ash emitted from coal-fired power plants is utilized for construction material, such as raw materials of cement and additives for concrete. In the future, if we can prepare the high purity silica material like silica filler from coal ash, it is expected to contribute to sustainable-growth societies. In this study, we investigated the appropriate conditions for extracting SiO₂ from coal ash with an alkaline solution, and the cleaning method for purifying silica. As a result of research, we were able to find these conditions, and confirmed the possibility of preparing the high purity silica material.

The aim of this study was to recover phosphoric acid and rare earths simultaneously. Dysprosium (Dy), yttrium (Y), and europium (Eu) were selected as rare earth elements. Since urine was expected to have pH buffering capacity, we also examined whether phosphoric acid and heavy metals could be recovered from acidic aqueous metal solutions by this method. Rare earths and phosphoric acid were precipitated and recovered not only from urine but also from sewage. In terms of the molar ratio, the efficiency was higher in sewage than in urine. The precipitation occurred even when the Dy solution was acidic, and the pH of the supernatant solution was close to that of urine, indicating that pH adjustment before and after precipitation was not necessary. These results indicate that this method, which utilizes the pH buffering effect of urine, can recover the heavy metals and phosphoric acid.

Electroless plating is a metal plating method that uses a reducing agent such as hypophosphorous acid, and is used in a variety of applications because it is possible to form a film regardless of the shape or type of material. In this process, plating solution is discarded as waste solution after repeated use. This waste liquid contains metals, hypophosphorous acid, and organic compound components for stabilizing the plating solution. Therefore, it is desired to reduce the burden of waste liquid treatment and recover metals and phosphorus.

We have developed waste liquid treatment and nickel recovery technology for electroless nickel plating waste liquid. This technology is characterized by continuous reaction using a column-type reactor packed with a catalyst. In this study, selection of catalyst, reaction conditions such as liquid temperature, and liquid conditions such as pH were examined.

The semiconductor material manufacturing industry has undergone rapid growth in the past few decades, and is one of the biggest industries that exhaust a large amount of waste solvent. Propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are most representative photoresistor thinner components for removing the photoresistor from the substrate edges or dispensing nozzles in the semiconductor material manufacturing industry (Hussain, A. et al. 2019). A large amount of waste thinners containing PGME and PGMEA is generated when the unreacted photoresistor is removed using a photoresistor thinner. Nevertheless of their expensive cost, the use of PGME and PGMEA has rapidly increased in a wide range of products because of their important advantages such as low systemic toxicity and minor particle formation. This great value of PGME and PGMEA from economic and environmental considerations highlights the need of their efficient recovery (Chaniago, Y.D. et al., 2015, 2016). The waste photoresistor thinner can be generally reclaimed by distillation. However, the energy-intensive character of distillation restricts the economics of the waste thinner recovery process. Further, the existence of azeotropes in the waste thinners also hinders the efficient recovery by simple distillation approaches. This study was aimed to develop a novel intensified distillation process for enhanced waste PGME and PGMEA recovery. A heat integrated double dividing wall column was proposed to achieve the separation task while minimizing the capital and operating costs for the recovery process.

A material called DES(Deep Eutectic Solvent), which is being studied as a next-generation carbon dioxide wet absorbent, is being newly researched. DES is a material made by simple physical mixing of HBA and HBD materials. DES is capable of both physical absorption, which traps carbon dioxide in its structure, and chemical absorption using an amine group, so it has a much higher absorption capacity than previous generation absorbents. In this study, we will fabricate several DESs using tetravalent ammonium salt as HBA and polyamine material as HBD. Afterwards, the factors affecting the absorption capacity for the halogen element of the tetravalent ammonium salt, the number of carbon chains, and the number of amine groups will be identified, and FT-IR, NMR, and DSC analysis will be conducted. In addition, we try to analyze the absorption mechanism more accurately by comparing each absorption capacity value.

This study proposes a simultaneous treatment method for brine waste and CO₂ using KOH as the CO₂ absorbent. The aim is to selectively separate the dominant ions, namely Mg, Ca, and Na, found in desalination by-products and solar sea salt waste. The process begins with the separation of Mg ions based on their solubility equilibrium, induced by the addition of KOH solution. The separated material is then analyzed for purity and utilized as a CO₂ absorbent. Next, the separation of Ca ions is accomplished by introducing K₂CO₃ to the solution after Mg separation, promoting precipitation based on the solubility balance of seawater ions. In this process, K₂CO₃ obtained from the CO₂ absorption process of KOH is utilized. Finally, Na ions are precipitated and separated by the combined addition of K₂CO₃ and CO₂ absorption. Precipitated metal carbonates are subjected to quantitative and qualitative analyses using techniques such as XRD and SEM. Overall, the proposed method offers a promising approach to address the environmental challenges associated with brine waste treatment and CO₂ mitigation. By utilizing KOH as an absorbent and selectively separating key ions, it presents a viable solution for enhancing the industrial applicability of desalination technology.

In this study, we tried to selectively recover zinc from electric arc furnace dusts(EAFD) through hydrometallurgy and produce zinc oxide. The metal content of EAFD was 22% Zn, 10% Fe, 19% Mn, and 0.9% Pb. 85% of zinc and manganese were leached from EAFD through leaching experiment in 1.6M sulfuric acid, 20% solid-liquid ratio, 60℃ for 1 hour. At this time, the pH of the leachate was 5.8, and Fe was not leached. A solvent extraction process was used to recover Zn from Mn in the leachate, and D2EHPA was selected as an extractant. 99% Zn was extracted through 32% saponified 0.8M D2EHPA, O/A ratio 2, and 3 stage counter-current extraction. Zn was stripped from loaded organic at an O/A ratio of 4 using 1.5M sulfuric acid, followed by ZnSO₄ powder was obtained through a vacuum distillation process. Finally ZnO powder was manufactured from the obtained ZnSO₄ by calcining at 800℃.

Recently, redox-mediated electrodialysis has emerged as a promising desalination technology. The unique feature of redox-mediated electrodialysis is to intervene in water stream channels in a redox flow battery system leading to desalination via a sustainable redox reaction. However, one of obstacles in the redox-mediated electrodialysis is low desalination capacity due to the limited cell voltage of around 1.2 V based on a narrow potential window of water. Therefore, this study aimed to improve the desalination performance of RFD. First, we adapted the organic supporting electrolytes for a redox reaction to extend the operational cell voltage. Second, the energy recovery process was introduced to improve the energy efficiency of the redox-mediated electrodialysis. As the major results, 1) the stable cell voltage was increased to 3.5 V by using the organic electrolyte for the sustainable redox reaction. 2) a significant improvement in the desalination performance was found, which is a 40-fold improvement in the salt removal rate of the redox-mediated electrodialysis compared to the system with aqueous supporting electrolyte. Moreover, the energy recovery process led to a 30% reduction in energy consumption. The results envision that the introduction of organic electrolytes in the redox-mediated electrodialysis can open new opportunities in the practical application including desalination and electrochemical resource recovery with an improved desalination performance via extension cell voltage and energy recovery process.

In this study, a simple and ecofriendly sequential extraction procedure was employed to recover rare earth elements (REEs) from coal ash effectively and its leaching efficiency from coal ash was compared with those of conventional procedures (Tessier and European Community Bureau of Reference (BCR)). Citric acid, which is a weak and environmentally benign acid, substituted acetate used in the existing extraction procedures, proving highly effective for extracting REEs from coal ash. Microwave-assisted thermal treatment further enhanced the REE leaching efficiency from coal ash, resulting in an overall recovery of 69.63%, which is 3.76 and 2.54 times higher than those achieved by the Tessier and BCR procedures, respectively. The results suggest that the majority of REEs was strongly associated with CaO, Fe₂O₃, and Al₂O₃, but not with SiO₂. The modified proposed sequential extraction procedure in this study can be used for the development of simple and effective recovery methods for REEs from coal ash wastes.

For stable combustion of general waste incineration, homogenization of the waste put into the furnace is required. For this purpose, a method of agitating the accumulated waste in the pit using an overhead crane with a bucket is adopted. For example, high waste is piled on top of waste with a low calorific value, and the bucket is repeatedly picked up and released to agitate. In addition, when there is a large deviation from the standard waste quality, the bucket is gradually opened while the crane is traversing or running to scatter the waste in the pit, aiming for an agitation effect. Recently, as the automation of facilities progresses, there is an increasing need to quantitatively grasp the scatter performed by operators. In this report, we verified how effective the scatter operation is in the homogenization of waste in medium- to long-term operation. Considering the difficulty of medium- and long-term verification using an actual machine, we developed a simulator using a discrete system simulation, evaluated the scatter operation, and clarified its characteristics.

In recent years, one of the important needs of the waste incinerator facilities was to ensure their sustainability, which can be achieved by doing both stable operation and cost reduction. Despite of the shortage of the highly experienced operators in the facilities and the seriousness of the response to the contingencies, both stable operation and cost reduction which contributed to the reduction of CO₂ emission and prevention of global warming, were ultimately required. This condition made the remote monitoring support systems become more indispensable than ever. Based on this situation, we build the remote monitoring /operation support systems utilizing the cloud system were built, the operation data were collected and processed altogether, and finally the obtained know-how was expanded and utilized for optimizing other incineration facilities. This effort was made by a joint research with Yokohama City. The result, it was confirmed that during the operation in 4 days, the manual intervention from the operators can be significantly reduced by the highly automated operation. Moreover, the amount of the generated steam for power generation, the CO and NOx concentrations in the flue gas, exhibited the equal performance compared to that of the normal operation. In the future, the highly automated operation will be conducted for a long period, with the aim of further improving accuracy and reducing the number of manual interventions, taking into consideration fluctuations in waste quality due to seasonal changes.

Stabilization of combustion is essential to stabilize power generation at refuse incineration facilities. To further stabilize combustion, we developed a model that manages information about refuse pits in each block of a 3D layer and estimates the properties of refuse at each location by reproducing the behavior of refuse and moisture. The model equations were developed for the change of refuse shape by dropping and grabbing refuse by a refuse crane, consolidation of refuse, evaporation of moisture from the surface of refuse, etc. We created a simulator that introduces these results.

Stable fuel supply in a stoker type refuse incineration plant is necessary for stable power generation, but it is difficult to achieve stable fuel supply by control based on a single rule, because refuse is affected by climate and other factors in addition to its uneven properties. In this study, we aimed at the automatic establishment of action rules using reinforcement learning for fuel feeder, and evaluated the difference in the optimization of the action of the feeder by the difference in the reward design using a simple simulator simulating the feeder.

Waste-to-energy plants are expected to become a decentralized energy facility due to their ability to generate stable power while sanitarily disposing of waste. Hitachi Zosen has been conducting research and development on the advanced control technology of waste-to-energy plants with AI technology, and has achieved certain results. In this paper, we improved our AI technology by adding a model that predicts future combustion images from actual combustion images in the last several tens of minutes. Furthermore, we developed an improved combustion control system that enhances the accuracy of the existing AI model with sensor values and additional control methods for ACC.

From 2021 to 2022, we conducted a demonstration test of this system at the Mito City Incineration Plant. As a result, the frequency of combustion deterioration decreased significantly and the number of manual operations was reduced by 86.4%. We also confirmed that stable operation of the incinerator was achieved for approximately 73 days using ACC+AI control, contributing to the streamlining of operational management.

Reduction of steam volume fluctuation is required for stable electric supply, which is generated by waste heat through a turbine, on waste disposal facilities. Conventional controlling steam volume by feedback control takes time until it reflects on current steam volume. Therefore, it results in an unstableness of steam volume because the volume is predicted based on previous date and it is differs from a current situation. This report introduces technology, which enables prediction of steam volume in a few minutes, and it causes steam volume fluctuation to minimize. It is achieved by machine learning using process data on waste disposal facilities. As a result, the 30 minutes moving average of steam volume is controlled within 3% difference from the set value.

Joint research partner PLANTEC Inc. developed the vertical stoker-type incinerator that eliminates the horizontal movement of waste as in conventional stoker furnaces and completes combustion without moving the waste in a vertical position. In this study, Basic experimental device was manufactured to simulate the carbon combustion zone formed in the lower part of the furnace. Preliminary experiments were conducted to obtain the necessary data to support the combustion conditions of the vertical stoker-type incinerator. Continuous measurements of sample mass and various gas concentrations in the combustion process became possible. Regarding the combustion phenomenon of woody pellets and charcoal used as a substitute for waste, the higher the furnace temperature, the faster the pyrolysis, ignition, and combustion, and the faster the mass reduction, but the difference due to the furnace temperature becomes smaller. It was found that woody pellets complete combustion in two stages: decomposition (gas phase) combustion of pyrolyzed volatiles and surface (char) combustion of fixed carbon mainly occurring in charcoal.

Numerical simulation was conducted by coupled analysis of DEM (Discrete Element Method) and CFD (Computational Fluid Dynamics) for a full-scale rotary combustor for municipal solid waste. The numerical analysis was conducted under general operating conditions and under conditions where the heating value of waste was reduced. As a result, the residence time of waste in the incinerator was almost the same as the past measurement results. However, it was suggested that the char combustion rate of the particles in this simulation was significantly different from the actual phenomenon and should be improved. When the heating value of the waste was reduced, the expected results were obtained, such as an increase in the concentration of H₂O in flue gas due to an increase in moisture of the waste, and an increase in O₂ concentration due to an increase in an excess air ratio.

Vertical Combustor was developed for the treatment of medical waste and are now recognized as being capable of treating a wide range of waste. Various measurements and analyses were carried out in a real incinerator to analyze the combustion of a Vertical Combustor, but since the characteristics of the waste were not constant and the flue gas characteristics varied significantly from one measurement to another, a small experimental furnace was built to simulate a Vertical Combustor and combustion experiments were carried out using wood pellets, which have stable characteristics, as fuel. The combustion mechanism of the Vertical Combustor was investigated. A Gold Furnace was used in the lower part of the furnace to visualize the combustion state in the layer, as the combustion emitted light that could be transmitted through the furnace to check the internal state. This experiment confirmed that the combustion characteristics of the small experimental furnace were similar to those of a real Vertical Combustor. In the future, experiments with different primary combustion air ratios and combustion experiments with fuels of different properties will be carried out to confirm the combustion mechanism and to investigate the combustion conditions that produce stable pyrolysis gases.

Oxyfuel combustion is one of promising solid waste incineration methods as part of CCUS technology in response to the global warming issue. Since the main component of the exhaust gas is CO₂ by supplying pure oxygen with recirculated exhaust gas to the furnace instead of combustion air, the high concentrations of CO₂ can be directly recovered without separating N₂ gas, which is a great advantage for reducing total CO₂ emissions. In this study, thermogravimetric analysis and kinetics analysis of RDF pyrolysis and char combustion were conducted under CO₂ and N₂ atmosphere to investigate the effect of oxyfuel combustion on waste incineration in a vertical stoker-type furnace. As a result, no significant differences were observed in pyrolysis and combustion behavior depending on two different atmospheric gases. The results of kinetics analysis showed that the kinetics triplets tended to be somewhat larger when CO₂ gas was used for reaction, but the difference was not so great especially for char combustion. It was concluded that the decomposition rate of the sample was dominated by the O₂ gas rather than N₂ or CO₂ gas during combustion.

There are a wide variety of types of garbage, and combustible garbage discharged from ordinary households includes various types of garbage such as kitchen waste, paper, plastics, and plants, each of which has a different moisture content and calorific value. In order to stabilize the combustion of the refuse incineration furnace, it is necessary to stir the refuse well in the refuse pit before throwing it in to keep the water content and calorific value constant. In recent years, the spread of image processing technology and advances in AI technology have led to the development of advanced automatic stirring technology that matches the state of the waste in the pit1). The key technology is to grasp the mixed state of dust from the pit image, and the statistical variation of the pixel color is used2). However, since there is no decisive index that expresses the mixed state of garbage, this research developed an index of "uniformity" of garbage using the concept of relative entropy used in information theory. Then, we applied it to the pit image and confirmed its effectiveness as an index for uniform agitation.

Recently, several international agreements have been concluded to recognize the seriousness of environmental problems and to solve them. In line with this, Korea also announced its 2050 carbon neutral vision and established a carbon neutral scenario. Under the carbon-neutral scenario, the cement industry must reduce its current CO2 emissions by 53% by replacing some of its fuel and raw materials with circular sources. To achieve this goal, combustible wastes such as waste tires and waste plastics, which are circulating resources, are used as auxiliary fuel in the firing process, which generates the most CO2 in the cement manufacturing process. However, the domestic circulating resource replacement rate is 35% as of 2021, which is significantly lower than the average replacement rate in the European Union. The reason is that the chlorine component of the waste plastic corrodes the inside of the kiln and the calcium chloride produced by reacting with the calcium contained in the raw material causes a coating phenomenon, which adversely affects the quality of cement. Therefore, this study analyzed the combustion reaction of cement kiln when using waste plastic auxiliary fuel for 2050 carbon neutral realization by using CFD analysis program ANSYS 2021 R2.

Sewage sludge is a stable biomass resource, but its energy utilization rate is low. Among the technologies for converting sewage sludge to energy, thermal pyrolysis and gasification is a promising pathway to generate electricity from the fuel gas produced or to convert it into hydrogen and chemical feedstocks, however, presence of small amounts of tar in the fuel gas has hindered its widespread application.

Here, the authors proposed a three-reactors circulating fluidized bed pyrolysis-gasification system with olivine, which shows catalytic activity for tar reforming, as a fluidizing medium for producing fuel gas from sewage sludge. In this paper, we report the results of gasification tests of dried sludge using a two-stage bubbling fluidized bed experimental setup developed to investigate and evaluate the effect of the type of fluidizing medium on the gasification behavior of sewage sludge.

Experimental results confirmed that the use of olivine as a fluidizing medium reduced the tar concentration by 94% and increased fuel gas recovery by approximately 1.8 times compared to silica sand, suggesting olivine as an effective fluidizing medium for a fluidized bed gasification system for energy recovery from sewage sludge.

Direct biomass fuel cells (DBFC) can directly convert the chemical energy of solid carbon and volatile components that constitute biomass into electrical energy, thereby enabling highly efficient power generation. Furthermore, DBFC do not require a boiler or gasifier, allowing for miniaturization and the effective utilization of unused biomass dispersed in various locations. In this study, power generation tests were conducted using activated carbon, cedar char, and simulated gas to verify the feasibility of DBFC. The results demonstrated that stable power generation can be achieved through regular refueling.

In addition, although the power density of DBFC is much lower than that of SOFC and PEFC fueled by gas, it was found that the same power density as MCFC can be achieved.

The authors are developing a process to produce low-carbon fuels such as SAF using R-CFP (REVO-Catalytic Fast Pyrolysis) technology by expanding the feedstock from woody biomass and waste plastics in addition to UCO (used cooking oil).

In this report, based on the results of previous studies, we fabricated a bench-scale (5 kg/day) R-CFP apparatus and attempted to produce a fuel consisting mainly of SAF from waste plastic. The test conditions were as follows: mixing ratio of waste plastic to carbon source catalyst: 3:1 (by weight), feed rate: 283.2 g/h, fluidized bed heating medium: carbon particles, fluidized bed N2 flow rate: 1.5 NL/min. As a result, the cracked oil yield was about 84 wt%, and the percentage of SAF in the cracked oil was about 57wt%, which is a good result.

In addition, high-quality bio-coke with a Gross calorific value of 7,830 cal/g was experimentally produced from catalytic fast pyrolysis residue, which is mainly composed of cedar powder, and bio-pitch obtained when cracked oil is separated.

In order to apply biomass coke to the shaft-type gasification and melting furnace, we investigated combustion quality using a combustion test apparatus that simulates the bottom of the furnace. As a result, we found that biomass coke consumes carbon at a high rate and absorbs heat due to solution loss reaction. There is a strong correlation between the geometric specific surface area of coke and the carbon consumption rate. It is thought that the difference in biomass coke raw materials and manufacturing processes has a relatively small effect on the consumption rate. In order to secure the same amount of heat as coal coke, it is necessary to reduce the geometric specific surface area and suppress the carbon consumption rate.

Aiming to reducing the direct use of fossil fuels in Kubota’s surface melting furnace, a series of test were conducted changing fuel from kerosene to RPF (waste plastic). As a result of the test, self-sustained combustion (fossil fuel-free) operation was achieved for more than 84 hours continuously. The running cost per ton of incinerated ash (assessed by fuel cost, exhaust gas treatment cost, and fly ash treatment cost) was reduced by 33%. Exhaust gas analysis and slag heavy metal content and elution tests were all below the standard values, thus it is confirmed that the operation using RPF were no problems. Regarding the distribution analysis of elements by melting process, it was confirmed that heavy metals migrate to fly ash, and high-melting elements, including precious metals, migrate to slag. In the future, we are planning to develop technology to utilize not only highly granulated RPF but also wastes (waste plastic, recycling residue, etc.) as fuel.

Recently, the momentum of the decarbonization movement has been rapidly growing. Pyrolysis gasification technology is attracting attention as one of the technologies that contribute to carbon neutrality and offer expanded options for the efficient generation of electricity using gas engines and chemical recycling, in contrast to current incineration. In this study, the characteristics of pyrolysis gasification of municipal solid waste were investigated using actual waste samples obtained from an incineration facility. By following the procedure outlined in Kansei No.95, a method was discovered to adjust waste samples that are representative even in small amounts for each component. Thermal analysis was conducted on these samples, which were categorized into biomass and plastic. The results showed rapid weight loss within different temperature ranges, allowing for the definition of their respective pyrolysis temperatures ranges. Furthermore, qualitative analysis using Py-GC/MS was performed to examine the main products of pyrolysis, revealing their similarity differs by components. Additionally, the heterogeneity of the municipal solid waste composition suggested that it might derive from fabric and kitchen waste, rather than paper or wood.

Thermal treatments including incineration are conducted as disposal methods for waste plastics, but for the waste plastics with polyvinyl chloride,etc., the hydrochloric acid gas (HCl) generated during thermal decomposition is a compound that leads to corrosion of equipment. To prevent equipment corrosion, it is necessary to suppress the generation of HCl gas. There is a method of adding calcium-based dehyrochloric material to waste as a method to suppress the generation of HCl gas during waste thermal decomposition and combustion, or by spraying absorbent in the exhaust gas containing HCl. In this study, the thermal decomposition characteristics of crushed mixed waste plastics and the amount of HCl emission were determined by experimental equipment, and the optimal conditions such as the amount of Ca addition, the addtion method, and the operation temperature will be proposed.

The sewage sludge energy conversion rate was only about 27% in FY2020, so there is a desire to recover more energy resources from sewage sludge to contribute to a decarbonized society. In this research, the focus was on the gasification of sewage sludge, which is an effective method for recovering energy and resources. The objective of this study was to quantify the effects of three parameters on pyrolysis products: temperature, steam, and olivine (as a bed catalyst). The following findings were obtained: The generation of char and tar decreased, while gas production increased with increasing temperature. Char gasification and tar reforming were observed at 800°C with steam. When sewage sludge was thermally decomposed with olivine under the same conditions, tar, which was not observed under other conditions, was detected, and the maximum higher heating value of the products was obtained. Qualitative analysis of GC-MS suggested a relationship between temperature and the mechanisms of tar and gas formation.

Reprocessing vacuum residue into shorter hydrocarbon products is an indispensable way to obtain fuels and chemicals due to the limitation of nonrenewable crude oil. However, the world energy transition to a zero-emission system in 2050 requires mainly renewable sources. The emergence of this transition is not easy due to the rate of technological turnover from design, experiments to industrial-scale production. Therefore, partial solutions such as process modifications by introducing bio-oil as renewable materials into an existing VR processing plan by a co-pyrolysis process can be a prospective option. This research aims to identify the synergetic effect of the VR_bio-oil co-pyrolysis. In this study, VR, distilled tall oil 2% and 10% rosin was pyrolyzed and co-pyrolyzed in a thermogravimetry analyzer. Then the study was conducted in a batch pyrolysis reactor at 470°C with a heating rate of 5°C/min and held for 5 hours. The study of VR_bio-oil co-pyrolysis in the TGA has no clear sign of the synergistic effect. Further investigation into the VR-bio-oil slow pyrolysis in the batch reactor reveals the synergistic effect on the VR-FA1 mixture by escalating gas and oil yield while alleviating the char yield. However, the synergistic effect did not clearly occur in the VR-FA3S co-pyrolysis.

Over the past decade, vehicles have become popular as a means of transportation, and the demand for vehicles is steadily increasing. Along with this growth is the demand for tires essential for vehicles. Tires are made up of natural rubber (NR), synthetic rubber, carbon black (CB), and steel, and that complexity makes reuse and recycling of them difficult. Pyrolysis is a promising method that converts tire rubber into useful resources such as isoprene, and other hydrocarbons. this method involves breaking the bonds of the tire rubber and reducing its molecular weight by applying heat in an inert atmosphere. We have reported a novel multi-step pyrolysis techniique starting with a low-temperature pyrolysis step that reduces the molecular weight of the rubber while retaining the isoprene skeleton. this work investigated the low-temperature pyrolysis characteristics of tire rubber by evaluating the yield of liquid rubber (lower molecular weight tire rubber) and its isoprene skeleton retention rate.

It is thought that the one of nitrile butadiene rubber glove recycling method is liquefaction by pyrolysis. While, because the main component of pyrolysis residue (NBR residue) is carbon, NBR residue is expected to be used as solid fuel by removing oxygen and hydrogen by heat treatment. In this study, the carbonization degree and hygroscopicity of NBR residue were evaluated after heat treating at 500, 600, 700, 800 and 900 ^oC. As a result, carbon weight ratio was almost unchanged by heat treatment. Whereas, oxygen weight ratio was highest when NBR residue was heat treated at 700 ^oC. However, over 800 ^oC, it was decreased with increasing the temperature. In addition, hydrogen weight ratio was decreased with increasing the temperature. Therefore, it was suggested that demethylation and dehydration was caused below 700 ^oC, and decarbonization was also caused over 800 ^oC. On the other hand, the hygroscopicity of NBR residue was decreased by heat treatment over 800 ^oC. These results suggested that NBR residue heat treated over 800 ^oC could be more useful as solid fuel.

The steel industry, which is partly responsible for global warming, is facing not only the problem of global warming but also the problem of coke depletion, and demand for alternative fuels to coke has been increasing. Therefore, we focused on waste plastics, which emit CO2 when incinerated, and unused woody biomass, and aimed to use them as a new way to reduce iron oxide. The results were analyzed using XRD to see if metallic iron was formed. The reduction of iron oxide by waste plastic resulted in a maximum reduction rate of 35.7%, and no metallic iron was produced. On the other hand, the reduction of iron oxide by woody biomass yielded a maximum reduction ratio of 86.2% and produced metallic iron, suggesting that woody biomass can be effectively used as a material for reducing iron oxide.

The global energy demand is continuously rising due to industrial progress. Still, due to limited availability of fossil fuels, the acquisition of sustainable resources has become a major concern. Organic wastes such as food waste and sewage sludge are prominent examples that can be quickly distributed and utilized for commercial purposes in comparison to other renewable energy sources. The London Protocol banned the dumping of organic wastes, so noted to emphasize the importance of their efficient conversion into valuable resources. Food waste exhibits a high calorific value; however, it contains a significant amount of chlorine. On the other hand, sewage sludge possesses a low calorific value but a high ash content (Kim, 2012). To address these characteristics, this study aims to create bio-coal by blending food waste, sewage sludge, and paper sludge in specific proportions, which will be evaluated as a solid fuel. Consequently, the hydrothermal carbonization (HTC) process proves to be well-suited for handling food waste and sewage sludge, both of which exhibit a high moisture content of 80%. Moreover, the heavy metal levels within the bio-coal meet the requirements outlined in the Waste Management Act. Analyzing the bio-coal composition, it was observed that the fixed carbon content is 22.4% and the volatile matter accounts for 66%, which represents the highest values among the bio-coals derived solely from food waste. However, with an increased proportion of sewage sludge in the mix, there was a gradual decrease in both fixed carbon and volatile matter contents, accompanied by an increase in ash content. Regarding the calorific value measurement, the bio-coal produced from 100% food waste exhibited the highest value at 6,510 kcal/kg, while the bio-coal derived from 100% sewage sludge yielded the lowest value at 3,260 kcal/kg. With an increase in the proportion of sewage sludge, there was a decline in the calorific value and volatile content. Nonetheless, fuel ratio analysis indicates an enhancement in fuel quality. By utilizing the van Krevelen diagram analysis, the coal band was refined as the proportion of food waste in the mix increased. Consequently, the H/C ratio decreased, resulting in a fuel ratio that closely aligns with the C-H-O ratio of coal species. Industrial analysis of bio-coal derived solely from food waste revealed the highest volatile and fixed carbon contents. Regarding the ash composition, when bio-coal was produced using 100% sewage sludge and paper sludge, the ash content was determined to be 41.14% and 46.49%, respectively. With respect to the mixing ratio, an increase in the proportion of food waste led to higher volatile and fixed carbon contents, while the ash content decreased. The results of elemental analysis indicated that as the proportion of food waste increased, there was an increase in carbon and hydrogen content, accompanied by a decrease in oxygen content. Notably, higher mixing ratios of food waste yielded greater amounts of volatile and fixed carbon, leading to an overall increase in carbon content. This, in turn, is expected to enhance the fuel characteristics due to the decreased oxygen content and increased hydrogen content. The mixed bio-coal composed of sewage sludge and food waste, it was found that regardless of the mixing ratio, the calorific value was satisfied. Whereas, for mixed bio-coal consisting of paper sludge and food waste, it only met the solid fuel standard of 3,000 kcal/kg when the paper sludge content was below 70%. The thermogravimetric analysis (TGA) results revealed that with an increase in the proportion of food waste in the mix, the weight of bio-coal decreased within the temperature range of 180°C to 500°C. These findings indicate a decrease in ash content as the mixing ratio of food waste increased. View PDF for the rest of the abstract.

Compared to JIS special slaked lime, highly reacted slaked lime uses a smaller amount, which has the advantage of reducing flue gas treatment costs and the amount of fly ash. On the other hand, it has been reported that 1,4-dioxane is generated from organic components contained in highly reacted slaked lime during the waste gas treatment process, and there have been cases where dioxane has actually been detected in elution tests of solidified fly ash from waste incineration facilities. We have developed a low environmental impact type of highly reactive slaked lime that suppresses the elution of organic components, and have attempted to suppress dioxane formation by using this type of lime. It was confirmed that the use of low environmental impact type highly reactive slaked lime can suppress the generation of 1,4-dioxane, which was observed with conventional highly reactive slaked lime, while maintaining the same acid gas removal performance. The generation of 1,4-dioxane is related to the organic components eluted from the highly reactive slaked lime, and the COD value of the highly reactive slaked lime can be used as an indicator of the amount of 1,4-dioxane contained.

To achieve carbon neutrality by 2050, CO₂ separation and recovery from CO₂ emission sources such as waste incineration plant exhaust gas is essential. The problem with CO₂ separation and recovery by chemical absorption is that a large amount of thermal energy must be supplied for CO₂ dissipation in the regeneration process. We have developed a total energy-saving process that includes a new non-aqueous absorbent and a CO₂ emission facility, and expect to reduce the thermal energy required for the CO₂ regeneration process to less than 1.5 GJ/t-CO₂.

This paper reports on the development of an energy-saving CO₂ capture process using a new non-aqueous absorbent.

We are developing a technology that converts CO2 into solid carbon as a carbon recycling technology. In this presentation, we will report the experimental results to understand the reaction characteristics of solid carbonization.

Recently, it has become desirable to install CO₂ recovery facilities in waste incineration facilities. However, there is concern that the CO₂ absorbent may deteriorate due to acid gas components in the flue gas at the guaranteed level of conventional dry treatment, and advanced treatment that can guarantee an acid gas concentration of 3 ppm or less is desired. In this study, a new type of dry flue gas treatment using renewable layered double hydroxide (LDH) as an adsorbent was investigated in order to achieve both advanced treatment of acid gases for CO₂ capture and maintenance of high efficiency power generation. The outline of the new dry-type flue gas treatment system and the repeated adsorption and regeneration tests of LDH, which is the basis of the new system, are reported.

The exhaust gas emitted from waste incineration facilities contains acid gas such as HCl, SOx, NOx, which needs to be treated properly. In the dry process for acid gas treatment, HCl and SOx are neutralized through the spraying of slaked lime (Ca(OH)₂). The neutralization products such as CaCl₂ are disposed of in landfills. However, leachate containing a high concentration salt releases from the landfills sites during rainfall. Consequently, it is needed to create an acid gas treatment process that does not generate neutralization products. Mg-Al layered double hydroxide intercalated with CO₃^2- (CO₃･Mg-Al LDH) can remove acid gas and regenerate its structure through anion exchange. It enables the development of novel acid gas recycling process using CO₃･Mg-Al LDH. This study aims to control the chemical properties of CO₃･Mg-Al LDH and achieve advanced acid gas treatment. And it investigates the characteristics of CO₃･Mg-Al LDH with high HCl removal capacity.