• New & Renewable Energy
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• v.19 no.4
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• pp.2-10
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• 2023

The current mandatory domestic biodiesel blending ratio is 3.5%, which is planned to be gradually increased to achieve carbon neutrality by 2050. The aim of this study was to improve domestic self-sufficiency in biodiesel raw oil by conducting a technical review on the possibility of utilizing waste oils, such as soup oil, chicken oil, and leather oil, as biodiesel feedstocks. These waste oils have an acid value that is too high to be converted directly into biodiesel. Therefore, a pretreatment to reduce the acid value is necessary. The neutralization process was examined as a potential technology for reducing the acid value. The oil recovery rate of the soup oil after neutralization was significantly low at 37.6 wt%. The oil recovery rates of leather oil and chicken oil were 66.49 wt% and 79.08 wt%, respectively. Based on biodiesel conversion experiment using waste oil with a reduced acid value, the conversions were analyzed as 89 wt%, 91.1 wt%, and 90.5 wt% for soup oil, leather oil, and chicken oil, respectively. Thus, it is technically possible to use soup oil, leather oil, and chicken oil as raw materials for producing biodiesel.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.1025-1032
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• 2009

This study investigated a possibility to develop an adsorption process for volatile organic compounds (VOCs) of the solvent emitted during dry cleaning. Pitch activated carbon fiber (ACF) was chosen as an adsorbent of VOCs, and an electric swing adsorption process was utilized for the reproduction of the adsorbent after the completion of VOCs adsorption. Effects of ACF types and several solvents such as trichloroethylene (TCE) and toluene were examined on breakthrough curves and amounts of adsorbed VOCs. ACF was pretreated under various conditions in order to enhance the amounts of the adsorbed VOCs. Temperatures and voltages were measured for the reproduction of the ACF after full adsorption. ACF having micropores exhibited high adsorption of TCE, and high surface area of ACF could increase the adsorption property of toluene. In general, ACF could adsorb 41~54% TCE of the adsorbent weight. The increase of inlet VOCs concentration significantly decreased the breakthrough time and slightly lowered the amounts of adsorbed VOCs. Thus, ACF could effectively adsorb VOCs in low concentration in the feed stream. ACF pretreated by heat under vacuum showed excellent toluene adsorption with controlling oxygen functional groups on the ACF surface, which revealed that vacant carbon site could be the adsorption point of toluene. Most adsorbed toluene was desorbed at $150^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.2
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• pp.44-52
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• 2012

As an alternative strategy in the era of high level petroleum cost, the study focused to suggest the way on the revitalization of renewable energy through the impact on introduction effect of renewable energy in green village. Total feasible solar energy production is 6.73 GWh/yr along with the biomass energy producing electric power energy is 134.06 GWh/yr, the two category's total electric power energy is 233.19 GWh/yr, which is possible to achieve the selfsufficiency of energy by 33% for total energy consumption of 705.80 GWh/yr in the region. The calculated feasibility on the carbon dioxide reduction, carbon dioxide reduction level is 1,891 ton_$CO_2$ by agricultural byproducts, 43,635 ton_$CO_2$ by livestock waste, 395 ton_$CO_2$ by municipal waste, 50,324 ton_$CO_2$ by forest byproducts, the total biomass shows 96,245 ton_$CO_2$, while the carbon dioxide reduction of solar light energy is 2,251 ton_$CO_2$, 1,383.3 ton_$CO_2$ by solar heat energy, the total solar energy shows 3,634 ton_$CO_2$. So total carbon dioxide reduction effect shows 99,879 ton_$CO_2$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.1 no.1
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• pp.65-72
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• 2003

Adsorption and desorption characteristics of methyl iodide at high temperature conditions up to 25$0^{\circ}C$ by TEDA-impregnated activated carbon and silver-ion exchanged zeolite(AgX-10), which are used for radioiodine retention in nuclear facility, were experimentally evaluated. In the range of temperature from 3$0^{\circ}C$ to 25$0^{\circ}C$, the adsorption capacity of base activated carbon decreased sharply with increasing temperature but that of TEDA-impregnated activated carbon showed higher value even at high temperature ranges. Especially, the residual amount of methyl iodide after desorption on TEDA-AC represented 30% lower value than that on AgX-10. However, it can be used as an adsorbent for the removal of methyl iodide up to 15$0^{\circ}C$ if it is preventing explosion by Ignition. The breakthrough curves of methyl iodide in the fixed bed packed with AgX-10 uP to 40$0^{\circ}C$ were compared upon the effects of bed temperatures, bed depth and input concentration of methyl iodide. Removal mechanism of methyl iodide on AgX-10 was proposed, based on the analysis of by-product gas generated from adsorption reaction.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.426-433
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• 2023

Capacitor performance was considered using coffee grounds-based activated carbon produced through oil extraction and KOH activation to increase the utilization of boiwaste. Oil extraction from coffee grounds was performed by solvent extraction using n-Hexane and isopropyl alcohol solvents. The AC_CG-Hexane/IPA produced by KOH activation after oil extraction increased the specific surface area by up to 16% and the average pore size by up to 2.54 nm compared to AC_CG produced only by KOH activation without oil extraction. In addition, the pyrrolic/pyridinic N functional group of the prepared activated carbon increased with the extraction of oil from coffee grounds. In the cyclic voltage-current method measurement experiment, the specific capacitance of AC_CG-Hexane/IPA at a voltage scanning speed of 10 mV/s is 133 F/g, which is 33% improved compared to the amorphous capacity of AC_CG (100 F/g). The results show improved electrochemical properties by improving the size and specific surface area of the mesopores of activated carbon by removing components from coffee grounds oil and synergistic effects by increasing electrical conductivity with pyrrolic/pyridinic N functional groups. In this study, the recycling method and application of coffee grounds, a bio-waste, is presented, and it is considered to be one of the efficient methods that can be utilized as an electrode material for high-performance supercapacitors.

• Composites Research
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• v.36 no.4
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• pp.281-287
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• 2023

Environmental pollution from waste and the climate crisis, due to rising global average temperatures, are reaching critical levels threatening human survival. Research is ongoing across various fields to solve this problem, with a key focus on developing eco-friendly, carbon-neutral materials. Our study aimed to integrate natural fibers, known for their environmentally friendly properties and lower carbon emissions, with carbon fibers. In general, combining high-strength and low-strength materials results in intermediate properties. However, we found that certain properties in our study exceeded those of typical carbon fiber composite materials. To validate this, we produced both carbon fiber composite materials and carbon fiber/natural fiber hybrid composite materials. We then compared their mechanical properties using a range of specific tests. Our results revealed that the hybrid composite material exhibited superior bending strength and fracture toughness compared to the carbon fiber composite material. We also identified the underlying mechanisms contributing to this strength enhancement. This breakthrough suggests that the use of hybrid composite materials may allow the production of stronger structures. Moreover, this can play a significant role in mitigating environmental pollution and the climate crisis by reducing carbon emissions, a major contributing factor to these global challenges.

• Journal of Climate Change Research
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• v.4 no.1
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• pp.51-61
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• 2013

To address the problems associated with climate change and energy shortage, Korea has been making efforts to turn waste materials into usable energy. Due to the ongoing efforts to convert waste materials into energy, waste incineration is expanding to utilize the heat generated, and the subsequent greenhouse gas emissions from these waste material incineration are expected to increase. In this study, a municipal waste incineration plant that generates heat and electricity through heat recovery was selected as a subject facility. Methods for estimating the greenhouse gas emissions in the municipal waste incineration plant that was selected as a subject plant were sought, and the greenhouse gas emissions and emission factor were estimated. The $CO_2$ concentrations in discharge gas from the subject facility were on average 6.99%, and the result from calculating this into greenhouse gas emissions showed that the total amount of emissions was $254.60ton\;CO_2/day$. The net emissions, excluding the amount of greenhouse gas emitted from biomass incineration, was shown to be $110.59ton\;CO_2/day$. In addition, after estimating the emissions by separating the heat and electricity generated in the incineration facility, greenhouse gas emission factors were calculated using the greenhouse gas emissions produced per each unit of output. The estimated emission factor for heat was found to be $0.047ton\;CO_2/GJ$ and the emission factor for electricity was found to be $0.652ton\;CO_2/MWh$. The estimated emission factor was shown to be about 17% lower than the $0.783ton\;CO_2/MWh$ emission factor for thermal power plants that use fossil fuels. Waste material types and fossil carbon contents were evaluated as being the factors that have major effects on the greenhouse gas emissions and emission factor.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.244.1-244.1
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• 2010

Bio energy development by using Low Calorific Gas Turbine(LCGT) has been developed for New & Renewable energy source for next generation power system, low fuel and operating cost method by using the renewable energy source in landfill gas (LFG), Food Waste, water waste and Livestock biogas. Low calorific fuel purification by pretreatment system and carbon dioxide fixation by green house system are very important design target for evaluate optimum applications for bio energy. Main problems and accidents of Low Calorific Gas Turbine system was derived from bio fuel condition such as hydro sulfide concentration, siloxane level, moisture concentration and so on. Even if the quality of the bio fuel is not better than natural gas, LCGT system has the various fuel range and environmental friendly power system. The mechanical characterisitics of LCGT system is a high total efficiency (>70%), wide range of output power (30kW - 30MW class) and very clean emmission from power system (low NOx). Also, we can use co-generation system. A green house designed for four different carbon dioxide concentration from ambient air to 2000 ppm by utilizing the exhaust gas and hot water from LCGT system. We look forward to contribute the policy for Renewable Portfolio Standards(RPS) by using LCGT power system.

• Journal of Animal Environmental Science
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• v.11 no.2
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• pp.97-102
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• 2005

Anaerobic decomposition is one of the most common processes in nature and has been extensively used in waste and wastewater treatment for several centuries. New applications and system modifications continue to be adapted making the process either more effective, less expensive, or suited to the particular waste in question and the operation to which it is to be applied. Animal manure is a highly biodegradable organic material and will naturally undergo anaerobic fermentation, resulting in release of noxious odors, such as in manure storage pits. Depending on the presence or absence of oxygen in the manure, biological treatment process may be either aerobic or anaerobic. Under anaerobic conditions, bacteria carry on fermentative metabolisms to break down the complex organic substances into simpler organic acids and then convert them to ultimately formed methane and carbon dioxide. Anaerobic biological systems for animal manure treatment include anaerobic lagoons and anaerobic digesters. Methane and carbon dioxide are the principal end products of controlled anaerobic digestion. These two gases are collectively called biogas. The biogas contains $60\~70\%$ methane and can be used directly as a fuel for heating or electrical power generation. Trace amounts of ammonia and hydrogen sulfide ($100\~300\;ppm$) are always present in the biogas stream. Anaerobic lagoons have found widespread application in the treatment of animal manure because of their low initial costs, ease of operation and convenience of loading by gravity flow from the animal buildings. The main disadvantage is the release of odors from the open surfaces of the lagoons, especially during the spring warm-up or if the lagoons are overloaded. However, if the lagoons are covered and gases are collected, the odor problems can be solved and the methane collected can be used as a fuel. Anaerobic digesters are air-tight, enclosed vessels and are used to digest manure in a well-controlled environment, thus resulting in higher digestion rates and smaller space requirements than anaerobic lagoons. Anaerobic digesters are usually heated and mixed to maximize treatment efficiency and biogas production. The objective of this work was to review a current anaerobic biological treatment of animal manure for effective new technologies in the future.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.222-222
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• 2011

Plastic product is increasing by the growth of its demand and most of refused plastics are incinerated or reclaimed. However, the refused plastic is not easily decomposed and has the environmental problem with its various toxic gas in case of incineration. Therefore, many countries such as USA, Japan, Germany and other developed industrial countries as well as Korea are interested in studying the recyclable resource of refused plastic. The macromolecular waste pyrolysis has the advantage of collecting of raw materials in high price and can at least get fuel gas or oil with high heat capacity. It also discharges low waste gas and low toxic gas including SOx, NOx and HCl heavy metals. However, pyrolyzed oil includes enough excess unsaturated hydrocarbons to form tar, which can cause the nozzle of engines to plug when pyrolyzed oil is used as fuel. Activated carbon was proven to have prominent adsorption capability among the other adsorbents that were mainly composed of carbon. This study examined the possibility of application in activated charcoal of its solid formation by analysing the feature of pyrolysis which is one of the chemical recycling methods and getting chemical analysis of the product and activated energy. Analyze the element of the oil produced by pyrolysis using GC-MS. The experiment of tar adsorption using fly-ash showed that fly-ash improved the optical intensity of pyrolyzed oil and decreased oxygen compounds in the pyrolyzed oil.