Search

This article proposes a novel Blood sample-based Emergency department (ED) Return (BER) scheme that predicts the ED return probability using LightGBM. In the proposed BER scheme, LightGBM makes predictions on ED return based on blood samples. Since blood sample analysis is one of the most common medical procedures, the proposed scheme can help to improve ED patient care for hospitals. The proposed BER smart health care system and internet of medical things (IoMT) blockchain network was tested from the ED of the Severance Hospital of Yonsei University, located in Seoul of South Korea. The results show that the proposed BER scheme is superior in predicting ED return visits based on achieving a higher Area Under the Curve of the Receiver Operating Characteristic performance, along with the advantage of using much lesser data and being faster.

Coal as catalytic support is advantageous in many respects. The pore structure and surface composition are controllable, and the high thermal conductivity can increase the thermal efficiency of the reactor. It is stable in acidic or basic media and it is easy to recycle the catalyst after use. In this study, six different coals were evaluated as catalytic supports based on their ability to disperse of the metal and their catalytic performance. Nickel particles with an average diameter of

As renewable energy source integration increases, P2G technology that can store surplus renewable power as methane is expected to expand. The development of a CO2 methanation catalyst, one of the core processes of the P2G concept, is being actively conducted. In this work, low-rank coal (LRC) was used as a catalyst support for CO2 methanation, as it can potentially enhance the diffusion and adsorption behavior by easily controlling the pore structure and composition. It can also improve the process efficiency owing to its simplicity (no pre-reduction step) and high thermal conductivity, compared to conventional metal oxide-supported catalysts. A screening of single metals (Ni, Co, Ru, Rh, and Pd) on LRC was performed, which showed that Ni was the most active. When Ni on the LRC catalyst was doped with a promoter (Ce and Mg), the CO2 conversion percentage increased by >10% compared to that of the single Ni catalyst. When the CO2 methanation activity was compared at 250–500 °C, the Ce-doped Ni/Eco and Mg-doped Ni/Eco catalysts showed similar or better activity than the commercial metal oxide-supported catalyst. In addition, the catalytic performance remained stable even after the test for an extended time (~200 h). The results of XRD, TEM, and TPR showed that highly efficient LRC-based CO2 methanation catalysts can be made when the metal dispersion and composition are modified.

The wood processing industry produces a significant amount of wood waste. Biomass valorization through pyrolysis has the potential to increase the added value of wood wastes. Pyrolysis is an important thermochemical process that can produce solid, liquid, and gas products. This paper aims to review the pyrolysis of wood wastes from Indonesia, including teak wood (Tectona grandis), meranti (Shorea sp.), sengon (Paraserianthes falcataria (L) Nielsen), and rubberwood (Hevea brasiliensis). The review is based on an in-depth study of reliable literatures, statistical data from government agencies, and direct field observations. The results showed that pyrolysis could be a suitable process to increase the added value of wood waste. Currently, slow pyrolysis is the most feasible for Indonesia, with the main product of charcoal. The efficiency of the slow pyrolysis process can be increased by harvesting also liquid and gaseous products. The use of the main product of pyrolysis in the form of charcoal needs to be developed and diversified. Charcoal is not only used for fuel purposes but also as a potential soil improvement agent.

Bamboo is a potential energy crop for the future and an attractive option to replace wood due to its fast growth, high productivity, and essential fuel characteristics such as low ash content, alkali index, and high heating value. This study aimed to evaluate the effects of torrefaction on the physical properties of andong (Gigantochloa pseudoarundinacea) and betung (Dendrocalamus asper) bamboo pellets. Torrefaction of bamboo pellets was conducted in an oxidative atmosphere using an electric furnace at 280°C with a residence time of 40 min. The results showed that oxidative torrefaction caused a decrease in the equilibrium moisture content of bamboo pellets. Water resistance and water adsorption test showed that the torrefied pellets are more resistant to water and relative humidity than the non-torrefied pellet, which is beneficial when the pellet is stored for a long time and in humid conditions. The results also showed that the density of bamboo pellets decreased after torrefaction.

The purpose of this study was to determine the effect of biochar application in growing media on the development ofthe roots of Falcataria moluccanna seedlings. Biochar from the waste of meranti wood (Shorea sp.) was produced bya slow pyrolysis process using a traditional kiln at a temperature of 600°C. The study was arranged in a completelyrandomized design with three treatments and 15 replications. The treatments were 100% topsoil (control), 5% biocharand 10% biochar addition to the planting media. F. moluccana was grown from seeds germinated in sand media. Afterone month, F. moluccana was transferred to polybags filled with planting media according to the treatment. Theobservations were conducted for four months. The parameters observed were root length, root volume, and root biomass. The results showed that the addition of biochar indicated a very significant difference in root length, root volume, and root biomass compared to the control. However, the two dosages showed no significantly different effect on root growth. This study concluded that the addition of 5% biochar meranti in the planting media could increase theroot growth of F. moluccana. Keywords: Biochar, Falcataria moluccanna, root growth.

Oil palm (Elaeis guineensis) empty fruit bunches (EFB) have not been utilized optimally. Currently, it is considered as a resource with low economic value. This biomass can be converted into bioenergy through a torrefaction process. Torrefaction is a mild pyrolysis at temperatures ranging between 200 and 300 °C, and it is generally performed under an inert atmosphere. The objective of this study was to evaluate the effects of torrefaction using Counter-Flow Multi Baffle (COMB) on the properties of oil palm EFB pellets. Torrefaction was conducted at 280 °C temperature with a residence time of 4 minutes. The results showed a decrease in the equilibrium moisture content and an increase in hydrophobicity after torrefaction using the COMB reactor. The change in the hygroscopic property could make the oil palm EFB pellet more stable against chemical oxidation and microbial degradation, hence self-heating and auto-ignition during storage could be prevented. The heating value of biomass increased after torrefaction. Torrefaction with the COMB reactor resulted in a heating value of 17.90 MJ/kg, which is comparable with the results of oxidative torrefaction (with longer residence time) of 18.28 MJ/kg. The results suggested that torrefaction using the COMB reactor could provide a great improvement in the quality of the bioenergetic properties of oil palm EFB pellets. However, the high ash content of the EFB pellets implied that the EFB pellets suitable for a small-scale application, but not yet for cofiring in power plants or as a feedstock for gasification . Keywords : Counter-Flow Multi Baffle; oil palm empty fruit bunches; renewable; torrefaction A B S T R A K Tandan kosong kelapa sawit ( Elaeis guineensis ) belum dimanfaatkan secara optimal. Saat ini bahan tersebut masih dianggap sebagai sumber daya bernilai ekonomi rendah. Tandan kosong kelapa sawit (TKKS) dapat dikonversi menjadi bioenergi melalui proses torefaksi. Torefaksi merupakan proses pirolisis ringan pada suhu berkisar antara 200 dan 300 °C dan umumnya dilakukan di bawah kondisi inert. Penelitian ini bertujuan untuk mengetahui pengaruh torefaksi dengan reaktor Counter-Flow Multi Baffle (COMB) terhadap sifat-sifat pelet TKKS. Torefaksi dilakukan pada suhu 280 °C dengan waktu tinggal 4 menit. Hasil penelitian menunjukkan bahwa torefaksi menyebabkan penurunan kadar air kesetimbangan dan menjadi hidrofobik setelah torefaksi dengan reaktor COMB. Perbaikan sifat higroskopis dapat membuat pelet TKKS lebih stabil terhadap oksidasi kimia dan degradasi mikroba, sehingga pemanasan sendiri dan pembakaran spontan selama penyimpanan dapat dicegah. Nilai kalor biomassa meningkat setelah torefaksi. Torefaksi dengan reaktor COMB menghasilkan nilai kalor 17,90 MJ/kg, yang sebanding dengan hasil torefaksi oksidatif dengan waktu tinggal lebih lama, sebesar 18,28 MJ/kg. Hasil penelitian menunjukkan bahwa torefaksi dengan reaktor COMB dapat meningkatkan kualitas energi pelet TKKS. Tetapi pelet TKKS masih memiliki kadar abu yang tinggi sehingga biomassa hasil torefaksi belum sesuai untuk cofiring di pembangkit listrik atau sebagai bahan baku untuk gasifikasi. Kata kunci: Counter-Flow Multi Baffle ; tandan kosong kelapa sawit; terbarukan; torefaksi

Ethyl acetate is a volatile organic compound (VOC) that has emerged as a major environmental pollutant and also one of representative components of bio-oil. In this study, mostly metallic Ni particles (size

The high moisture level and ash content of biomass often hinder its further processing. In this study, torrefaction and degradative solvent extraction were employed to upgrade rice husk waste. Biomass torrefied at five different temperatures, in addition to dry raw biomass for comparison, was extracted in 1-methylnaphthalene at 300 °C for 1 h. Two solid fractions were obtained: extracted biomass (EB) and residue biomass (RB). The extraction yields of the EB and RB were 12–19.3% and 31.7–52% (db), respectively. The torrefaction temperature affected the extraction yields and slightly influenced product characteristics. The EB had almost no ash content as it was concentrated in the RB. However, both the EB and RB had higher heat values and carbon content as well as lower oxygen content than the raw biomass. Therefore, our findings suggest that EB could be utilized not only as fuel but also as functional materials.

Utilization of coal is currently limited to coal-fired power plants and iron smelting, partly because of the incombustible ash in coal and the inability of existing technologies to modify its properties. This work investigates whether the gasification behavior of ash-free coals (AFCs) can be modified. Sixteen different AFCs were prepared using variously ranked coals (Eco, Cyprus, Drayton, and Hail Creek) and extraction solvents with different polarities (N-methyl-2-pyrrolidone, ethylenediamine, 1-methylnaphthalene, and tetralin). Next, the reactivities of the AFCs in steam gasification at 800 °C were tested, and the results are discussed taking into consideration their compositional differences. A combination of low-rank coals and polar solvents produces reactive AFCs that can be catalytically gasified under mild conditions. In contrast, AFCs extracted using nonpolar solvents are less reactive and possibly applicable as a carbon electrode precursor. In short, the properties of AFCs can be changed to some ...

As a result of the characteristics of biomass, biomass exploitation as a secondary fuel feedstock in co-firing is only technically and economically acceptable in the range of 5–10% (w/w). In this study, torrefaction and solvent extraction as biomass pretreatments were conducted to address feedstock limitations, making a larger share of biomass for co-firing feasible. The physical and chemical characteristics of the solvent-extracted biomass were investigated using proximate analysis, ultimate analysis, thermogravimetric analysis, and Fourier transform infrared spectroscopy. Biomass torrefied at 200, 250, 270, 300, and 330 °C was extracted by nonpolar organic solvent 1-methylnaphthalene at 350 °C for 1 h to produce ash-less biomass (extracted biomass). A dry, raw, woody biomass was also extracted under the same conditions to see the effect of torrefaction on the characteristics of extracted biomass and residue biomass. The result shows that solvent extraction was effective in producing ash-less biomass, wi...

The objective of this study was to determine the properties of biochar from meranti (Shorea sp.) and oil palm (Elaeis guineensis) empty fruit bunches (OPEFB). Biochar was produced using a traditional kiln with a temperature of 400°C and 600°C. The char yield, pH, and proximate analysis were evaluated. The results showed that the maximum char yield was obtained at 400°C, and the increase in temperature resulted in decreased char yield. At the same pyrolysis temperature, char yield was higher in meranti than OPEFB. The results revealed that the pH of meranti and OPEFB changed into basic after pyrolysis, which is essential when biochar is added to soil to neutralize soil acidity and increase the soil cation exchange capacity. The results also showed an increase of fixed carbon in meranti and OPEFB after pyrolysis at 400°C and 600°C. The higher heating values (HHV) in meranti and OPEFB increased after pyrolysis, with a remarkable increase of HHV observed in meranti than OPEFB, showing a higher potential of biochar from meranti to be used for bioenergy application than OPEFB.

The objective of the study was to examine the effect of biochar addition on the growth of Paraserianthes falcataria seedlings. Biochar from shorea was produced using a traditional kiln at 400 °C and 600 °C. The scarification of P. falcataria seeds were conducted using hot water with temperature at 80 °C and then soaked for 24 h. The seeds were then spread on to the germination media and after germinated, the seedlings were moved to polybags contain soil and biochar. Two dosages of biochar such as 25 and 50% were applied and compared with control. The research was arranged in a completely randomized design with 15 replicates. The examination of seedlings growth was conducted one week after transplanting, then subsequently monitored every month. The results showed that the addition of biochar improved the survival rate of seedlings, height and diameter increments, root length and root volume. The results showed a potential of using biochar to improve the growth of P. falcataria seedlings in the nursery.

Coal that contains >70 wt% carbon is possibly an economical option as fuel for highly efficient power generation system such as catalytic coal gasification and direct carbon fuel cell, when mineral ashes in coal are removed. In this work, ash-free coals (AFs) are prepared via thermal extraction of carbonaceous components in parent raw coal (PA) and chars of AFs are made by pyrolysis at 300–900 °C. Then, those are characterized concerning the compositional change associated with the extraction and carbonization condition, based on the steam gasification behavior. The composition of AF chars changes depending on the polarity of the extraction solvent. Chars of AF extracted using a polar solvent (N-Methyl-2-Pyrrolidone) show much higher gasification rate than that using a non-polar solvent (1-methylnaphthalene). The addition of K2CO3 catalyst to the AF chars improves the conversion rate significantly, showing that AFs can be a feedstock of the catalytic coal gasification. The effect of the pyrolysis temperature on the reactivity varies between the AFs, implying the difference in the aromaticity and the chemical composition. The property of the AF chars that can be somewhat adjusted by the extraction and pyrolysis condition possibly provides a custom-made product for a particular application including a precursor of the functional carbon materials.

Coal is able to form metal complexes via ion-exchange associated with the carboxyl functional groups. In the work, this ion exchange behavior is utilized to disperse catalytically active metals across a coal support. Coal is composed of mostly aromatic rings that exhibit attractive interaction with toluene, and which can enhance the chance of catalytic contact, combined with metal carboxylates. Nickel ions are exchanged on several coals of different ranks, where only low rank coals (LRCs) achieve the fine metallic dispersion. ICP analysis and TEM pictures confirm that 5–18 wt% of nano-scale nickel metals are all around the LRC matrix as a result of forming metal carboxylates. The nickel catalyst supported on an LRC (Ni/LRC) is applied to the steam reforming of toluene at various conditions (temperature, space velocity, and S/C ratio). It shows relatively high and consistent activity even at 400 °C during 10 h continuous operation, indicating that carbon deposition is expected to be less severe probably because of the metal-coal support interaction that avoids the formation of free NiO.

This study investigated the changes in spontaneous combustion susceptibility of low-rank coal through preoxidation processing at low temperatures. The pre-oxidation processing on low-rank coal was conducted for a certain time at 60–150 °C in normal atmospheric conditions. The oxidation characteristics of coal at low temperature were investigated by measuring the temperature of coal and consumption of O2 gas during the pre-oxidation processing. Physical properties of coal and changes in crossing-point temperature (CPT) caused by the pre-oxidation processing were also analyzed. Higher the temperature for pre-oxidation, the more consumption of O2 gas in coal, and larger increase in temperature of the coal was observed. There were no significant changes in the weight of coal samples and calorific value in pre-oxidation processing upto 130 °C. It was found, from Fourier Transform Infrared Spectroscopy (FTIR) analysis, that the coal which underwent pre-oxidation processing upto 80 °C showed no significant difference from raw coal in terms of content. However, higher the temperature for preoxidation, larger decrease in aliphatic hydrocarbon and ether in the coal. As a result of CPT measurement, higher the temperature for pre-oxidation, greater the increase in CTP value of the coal. Therefore, it is expected to reduce the risk of spontaneous combustion susceptibility through the pre-oxidation method. From these results, it was confirmed that the spontaneous combustion susceptibility of the coal can be suppressed without a significant reduction in weight and calories through the preoxidation processing of low-rank coal under the proper conditions.

Catalytic gasification of raw coals at mild condition is not realized yet mainly due to deactivation of catalysts via their irreversible interaction with mineral matters in coal. As a means to achieve repeated use of catalysts, four different ash-free coals (AFCs) containing less than 0.2 wt% ash are produced in this work. Steam gasification of ash-free coals (AFCs) and their parent raw coals of various ranks ranging from lignite (Eco) to coking coal (Posco) is performed in a fixed bed reactor at 700–900 °C. Regardless of the rank of the parent raw coals, all the AFCs behave like a highly carbonized coal such that their gasification rate are similarly slow and they exhibit relatively low H 2 /CO ratio. The steam gasification and associated CO to CO 2 conversion of the AFCs are, however, significantly enhanced by K 2 CO 3 , resulting in the higher H 2 /CO and CO 2 /CO molar ratio.

Low rank coal (lignite) can be successfully utilized in thermal power plants through the pretreatment of the coal. The price of low rank coal is approximately one third that of steaming coal. However, it is difficult to utilize in thermal power plants due to its high moisture content, and instability. Therefore, a drying process must precede the coal entering the power plant. In this study, the drying kinetics of Indonesian low rank coal (IBC) was investigated in a fixed-bed reactor and thermobalance. In the fixed-bed reactor, the drying mechanism is best represented by a phase boundary reaction. Also, the drying kinetics was evaluated in terms of particle size, inlet gas temperature, drying time, gas velocity and the L/D ratio. However, in a thermobalance, the moisture removal rate is mainly dependent on drying temperature. The rate equation for the drying of coal can be obtained from the experimental data.

This work describes the performance of direct carbon fuel cell (DCFC) fueled by an ash-free coal. Carbon is typically originated from coal that is readily available and economical. However, employing coal in DCFC has been excluded, mainly due to its left-behind ash after the cell reactions. In the study, carbonaceous ash-free component of coal was extracted using organic solvent, which was then evaluated as a DCFC fuel. An electrolyte-supported SOFC structure was adapted to build DCFC. When an ash-free coal was internally gasified to fuel gases, the power density was improved by more than 20%, compared to N2 environment. Both an ash-free coal and its reformed gases were found to take part in the electrochemical reactions.

Low-rank coals–lignite and subbituminous coals–refer to the lowest and second lowest rank of coals. Unlike high-rank coals deposited in specific areas, low-rank coals are evenly distributed around the world and their reserves are approximately 500 billion tons, which is similar with that of high-rank coals. Low-rank coals are high in moisture or ash content and susceptible to spontaneous combustion. Since low-rank coals are high in moisture, using them as fuel in energy-producing facilities like power plants increases coal consumption, emitting more CO2 and lowering power generation efficiency. This chapter introduces upgrading and advanced cleaning technologies, which are low-carbon utilization technologies. Upgrading is necessary to use as a fuel for high efficiency and low emission combustion and conversion technologies. Upgrading is a process of removing moisture or ash from low-rank coals before using the coals to enhance facility efficiency. As such, we would like to introduce existing coal drying technologies and stabilization technologies as well as new drying/stabilization technologies, which are under development. This chapter also introduces the production technology of ash-free coals which is expected to be used for various purposes in the future.

본 연구에서는 석탄의 연화온도보다 낮은 온도에서의 무회분 석탄 제조공정인 온순조건 용매추출 공정의 경제성을 분석하였다. 이를 위해 인도네시아 석탄 산지에 6,000 톤/일 규모의 온순조건 용매추출 플랜트를 건설하는 것으로 가 정하였으며, 이 설비에 대하여 $96백만의 투자비용과, 내용년수 15년에 대한 IRR, B/C ratio, NPV, DPP를 계산하였다. 계산 결과 이 플랜트의 IRR은 31%, NPV는 $87백만, B/C ratio는 1.08, DPP는 3.9년인 것으로 계산되었으며, 이를 통해 석탄의 온순조건 용매추출 플랜트는 충분한 경제성이 있는 것으로 판단하였다. 민감도 분석 결과 무회분 석탄의 판매가 격보다는 원료탄의 구입가격과 고품위 잔탄의 판매가격이 온순조건 용매추출 플랜트의 경제성을 크게 좌우하였다.

Thermal extraction of a sub-bituminous coal (Roto south) using 1-methylnaphthalene solvent has produced ash-free coals successfully. The extracted (EC) and residual coal (RC) as well as its parent coal (PC) were pyrolyzed at 300–900 °C and then the carbonized products were characterized. The extracted coal (EC) contained lower molecular weight components than PC and RC, showing much higher fuel ratio after the pyrolysis. EC is expected to be advantageous over PC and RC when applied to coal gasification and reforming, because EC is readily decomposed and volatized. The heating value of EC chars (7,610–8,120 kcal/kg) was independent of the pyrolysis temperature and was higher than those of PC and RC chars, especially for the chars carbonized below 600 °C. The oxygen content of PC chars at T≤600 °C was mostly at least twice that of EC/RC chars, pointing out the difference in the chemical composition. 13CNMR and FT-IR spectra revealed the release of aliphatic hydrocarbons and reactive functional groups with increasing temperature, in agreement with ultimate/proximate analysis results.

This study investigated the behavior of upgraded low rank coal produced by a coal–oil slurry dewatering process regarding moisture readsorption, low temperature oxidation, and spontaneous combustion. The upgraded low rank coal had higher heating values than raw coal. It also showed lower moisture readsorption than raw coal and had less susceptibility to low temperature oxidation and spontaneous combustion. This seemed to result from the coating of the asphalt on the surface of the coal, which covered fine pores and suppressed the active functional groups from reacting with moisture and oxygen in the air. The increasing upgrading pressure negatively affected the moisture readsorption, low temperature oxidation, and spontaneous combustion.

Fry-drying of coal slurry is one of the upgrading low rank coal processes. It consists of slurry mixing, slurry dewatering, solvent recovery and briquetting. Cost estimation and economic feasibility are examined for the upgrading low rank coal process based on capacity of 1 million ton/yr. In case that investment costs are $100,000,000, discount rate is 12%, and service life is 20 years, the results of economic analysis are enough to satisfy the evaluation criteria of investment such as IRR, B/C ratio, NPV and discounted payback period. According to sensitivity analysis, investment value are very sensitive to raw material cost and product price. Since the bituminous coal price is currently soaring, it is expected that the investment value will increase more and more.

Lignite is a low rank coal which is evenly distributed throughout the world and accounts for 45% of the total coal reserves. As it has a higher moisture content, its moisture content must be reduced in order to utilize it in power plant. In the present work, experiments on lignite has been done using a lab scale fluidized-bed reactor. Drying lignite through fluidized-bed reactor has a higher drying rate because there is good contact between particles and gas in the fluidized-bed reactor. Fluidized-bed drying can use air of 1.5 times of the minimum fluidizing velocity performance at bubbling fluidized-bed. Experiments have been performed on coal particle sizes of 0.3–1 mm, 1–1.18 mm and 1.18–2.8 mm, with operating temperatures being 100°C, 125°C and 150°C, respectively. It is found that fluidization has a higher drying rate due to the heat transfer rate through air velocity. Hence, moisture content in lignite can be dried to a desired value with a time interval of 10 min. The experiment through fluidized-bed reactor is expected to be useful for saving money and time.

Highly ordered three-dimensional V-SBA-16 materials were prepared at mild acidic condition by tuning the key parameters for metal substitution such as molar ratio of silica to 1-butanol (TEOS/BuOH), water to hydrochloric acid (H 2 O/HCl ratio) and hydrothermal aging time in the initial gel containing 0.0035 F127/0.01 V/0.91–2.00 TEOS/2.08–0.76 BuOH/0.70–1.16 HCl/118.6–120.1 H 2 O. The extent of mesopore structural ordering was confirmed by small-angle X-ray scattering and nitrogen adsorption isotherms. The presence of incorporated vanadium in a highly dispersed tetrahedral state was confirmed by electron spin resonance (ESR) and Drs-UV spectroscopy. The NH 3 -TPD profile showed that the materials tend to posses medium-acidic V–OH sites; strong-acidic sites increased with decreasing Si/V ratios. TEM analysis shows that the cubic phase was stable up to 3.6 wt.% vanadium loading. The activity of V-SBA-16 was tested for the selective oxidation of ethylbenzene to acetophenone by studying the effect of temperatures, time on stream, and the mole ratio of ethylbenzene to TBHP.

The physical, chemical and electrical characteristics of cement dust generated from a cement plant have been investigated by using a dust analyzer and a high voltage conductivity cell based on JIS B 9915. Major constituents of raw material cement dust generated from the first grinding process are CaO (41.77%), SiO2 (11.72%), Al2O3 (3.45%), and Fe2O3 (1.47%), while the cement clinker dust generated from the second grinding process consists of mainly CaO (48.09-65.50%), SiO2 (14.02-21.56%), Al2O3 (2.86-3.76%), and Fe2O3 (1.77-2.66%). Size distribution of the raw material cement dust is bi-modal in shape and the mass median diameter (MMD) is 3.68 μm, whereas the cement clinker dust also displays bi-modal distribution and the MMD of the cement clinker dust is in the range of 7.89-58.78 μm. The resistivity of raw material cement dust is so high as 1014 ohm·cm at 300 °C, that cement dust would not precipitate well by the electrostatic precipitator.

A hybrid dust-collector combining electrostatic charging with fabric filtration was developed and its performance characteristics were evaluated. Charged particles build porous dendritic structure on the filter surface by electrostatic attraction, increasing the collection efficiency of dust particles and reducing the pressure drop through the deposited dust layer and filter media. The cleaning performance of the dust layer is improved because the dendritic structured dust layer may be removed more easily by pulse jet cleaning flow. The results of the experiment showed a reduction of fine particle emission by 37% and 13% energy saving by precharging dust particles before filtration.

A method of determining an optimum blank shape for non-circular deep drawing processes is investigated. The rigid–plastic finite-element method (FEM) is introduced and the computer program is developed. The ideal shape of a drawn cup with uniform wall height is assumed and the metal flow is traced backwards step-by-step to predict the initial blank shape of the ideal cup. As examples of non-circular deep-drawn products, two cases of drawn cups with quadrilateral punch shapes and a L-shaped cup are considered, the optimum blank shapes for each case being proposed and compared with experimental results.

Despite vast reserves, low rank coals are not used as a main fuel in industry because their high moisture content, potential spontaneous combustion in transportation and storage, and the low thermal efficiency during the combustion in conventional power plants. With a view to secure and strengthen low rank coal’s position as high available energy source, in recent years many attempts have been made to develop technologies for an energy-efficient upgrading process. This paper reviews these technologies mainly categorized as drying for reducing moisture, stabilization for decrease self-heating characteristics and cleaning the coal for reducing mineral content of coal. Drying technologies consist of both evaporate and non-evaporative types. There are also highly advanced coal cleaning technologies that produce ash-free coal. The paper discusses some of the promising upgrading technologies aimed at improving these coals in terms of their moisture, ash and other pollutants. Korea’s activity for the drying and stabilization technologies will be introduced in this paper and the utilization of dried low rank coal also introduced.