• Journal of the Korea Institute of Building Construction
• /
• v.9 no.3
• /
• pp.73-78
• /
• 2009

Coal ash is a by-product of the combustion of pulverized coal, and much of this is dumped in landfills. The disposal of coal ash is one of the major issues for environmental problems. In this paper, the effects of the kinds and replacement ratio of coal ash on the durabilities of concrete mixtures are investigated. Fine aggregate was replaced with coal ash(fly ash and bottom ash) in five different ratios, of 0%, 10%, 20%, 35%, and 50% by volume. Test results indicated that the compressive strength increased with the increase in fly ash percentage. The loss of compressive strength of bottom ash concrete mixes after immersion in sulphuric acid solution was less than in the control mix(BA0). In addition, the carbonation depth of fly ash concrete mixes was lower than the control mix(FA0).

• International journal of advanced smart convergence
• /
• v.4 no.1
• /
• pp.162-178
• /
• 2015

Petroleum based fossil fuels used to power most processes today are non-renewable fuels. This means that once used, they cannot be reproduced for a very long time. The maximum combustion of fossil fuels occurs in automobiles i.e. the vehicles we drive every day. Thus, there is a requirement to shift from these non-renenewable sources of energy to sources that are renewable and environment friendly. This is causing the need to shift towards more environmentally-sustainable transport fuels, preferably derived from biomass, such as biodiesel blends. These blends can be made from oils that are available in abundance or as waste e.g. waste cooking oil, animal fat, oil from seeds, oil from algae etc. Waste Cooking Oil(WCO) is a waste product and so, converting it into a transportation fuel is considered highly environmentally sustainable. Keeping this in mind, a life cycle assessment (LCA) was performed to evaluate the environmental implications of replacing diesel fuel with WCO biodiesel blends in a regular Diesel engine. This study uses Life Cycle Assessment (LCA) to determine the environmental outcomes of biodiesel from WCO in terms of global warming potential, life cycle energy efficiency (LCEE) and fossil energy ratio (FER) using the life cycle inventory and the openLCA software, version 1.3.4: 2007 - 2013 GreenDelta. This study resulted in the conclusion that the biodiesel production process from WCO in particular is more environmentally sustainable as compared to the preparation of diesel from raw oil, also taking into account the combustion products that are released into the atmosphere as exhaust emissions.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.10 no.3
• /
• pp.343-348
• /
• 1986

An optical interference method was developed for measuring rapidly growing and evaporating liquid condensate films (e.g., Na$_{2}$SO$_{4}$, $K_{2}$SO$_{4}$) on solid surface exposed to flowing combustion product gases at film thicknesses well below the onset of complications due to run-off. To develop this optical system, this study investigated the optical parameters (e.g., polarization state, incident angle, target roughness, etc.) Trends for the Na$_{2}$SO$_{4}$(l) and $K_{2}$SO$_{4}$(l) deposition rates as a function of target temperature using this optical measuring system agree with the theoretical prediction of the vapor deposition. This study was able to extend the experimental range for vapor plus condensed phase transport and deposition. While previously unable to measure the evaporation rates interferometrically, these rates are estimated from the results of the investigation of polarization states.

• Transactions of the Korean hydrogen and new energy society
• /
• v.12 no.4
• /
• pp.277-285
• /
• 2001

We developed a compact, 10 kWe, purifier-integrated reformer which supplies hydrogen for fuel cell vehicles. Our proprietary technologies regarding hydrogen purification by palladium alloy membrane and catalytic combustion by noble metal coated wire-mesh catalyst were combined with the conventional methanol steam reforming technology, resulting in higher conversion, excellent quality of product hydrogen, and better thermal efficiency than any other systems. In this system, steam reforming, hydrogen purification, and catalytic combustion take place all in a single reactor so that the whole system is compact and easy to operate. The module produces $8.2Nm^3/hr$ of 99.999% or higher purity hydrogen with CO impurity less than 10 ppm, which is equivalent to 10 kWe when PEMFC has 45 % efficiency. Thermal efficiency of the module is 81 % and the power density of the module is 1.6 L/kWe. As the results of experiments, cold-start time has been measured about 20 minutes. Response time of hydrogen production to the change of the feed rate has been within 1 minutes.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.11 no.4
• /
• pp.38-45
• /
• 2007

A liquid rocket engine fuel-rich gas generator has been developed for the first time in the country, which can produce combustion gas over the rate of 4 kg/s at 900 K and 58 bar. The gas is not only for driving a turbopump but also for providing heat source for propellant supply tanks. The final design of the gas generator had been fixed based on the concept and preliminary development tests, and was validated through structure and heat transfer analysis. The manufacturing involved precision machining, surface finish, and special welding technique. The final assessment on the characteristics of ignition and combustion had been carried out for two different versions of injector heads. This concluded that the present product satisfies the development requirements such as spatial temperature distribution and the development has been successful.

• Korean Journal of Materials Research
• /
• v.5 no.7
• /
• pp.869-879
• /
• 1995

TiAi intermetallic compound has been extensively studied for possible high temperature structural applications because of its high specific strength at high temperature, high creep resistance, and good oxidation resistance at elevated temperatures. In addition to its good properties, an economic manufacturing routes should be developed for this material to be used more extensively. One of the promising route in manufacturing TiAl intermetallics is the Self-propagating High-temperature Synthesis (SHS) method. Thus in this study, an attempt was made to study the mechanism of the SHS process in TiAl synthesis. The composition of the sample was Ti-(45, 50, 53)at% Al and the microstuctures of the products were analyzed using optical microscope and scanning electron microscope. When the phases formed at the main SHS reaction of whicyh combustion temperature is higher than the melting temperature of aluminum were identified as TiAl and Ti$_3$Al ; Ti$_3$Al cores surrounded by TiAl phase. In order to increase the combustion temperature, carbon was added 5 and 10at.%. When the carbon content was 10at.%, the heat of the reaction was large enough to melt the phase formed and that is consistent with the theoretical calculation results of the adiabatic temperature. The combution temperatue, which was measured by a computer data acquisition system, increased with the carbon content. The phases formed from the reaction involving the carbon added were indentified as TiAl and Ti$_2$AlC using XRD. The vickers hardness of the reaction product increased with the carbon content.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.21 no.2
• /
• pp.51-55
• /
• 2013

This research conducted component analysis of pellet fuel using livestock waste and agricultural by-product and combustion characteristics. As the result of analyzing the characteristics of solid fuel using livestock waste, three components, element analysis, and heating value were suitable for the standard of solid fuel. In addition, content of ash consisted of high concentration of K, P, Na indicating the possibile usage as a soil conditioner. However, it was not suitable for solid fuel using only livestock waste due to the relatively low heating value. To improve the heating value and early ignition, we mixed agricultural by-products (i.e., chaff and sawdust) into livestock waste. The mixed material showed significant increase of combustibles and heating value with decrease of moisture content compared to the livestock waste only.

• Journal of the Korean Society of Tobacco Science
• /
• v.28 no.1
• /
• pp.23-30
• /
• 2006

In order to improve the final product quality, tobacco industry has gradually decreased the size and number of steams in the cigarette. Especially, steams bigger than $3{\times}3$ mm($length{\times}thickness$) and $2{\times}10$ mm($width{\times}length$) are not acceptable in the process as objectionable stems. A total number of 12 samples where the $length{\times}tickness$ samples were prepared by decreasing the present sample ($3{\times}3$ mm) with 1 mm up to $1{\times}1$ mm, and the $width{\times}length$ samples were prepared by decreasing the present sample ($2{\times}10$ mm) with 2 mm up to $2{\times}6$ mm for the stems in leaf and stems in expanded cut-tobacco were prepared to apply a fire ball drop test using stems. In addition, cigarettes were produced for these stems in order to analyze the forced fire ball drop including the burning, encapsulation and unencapsulation pressure drop and a single or unspecified direction combustion. Based on the results of the test, it was evident that the fire ball drop in the stems in expanded cut-tobacco presented a lower level than that of the stems in leaf. Also, the stems in expanded cut-tobacco presented a larger swelling and higher burning for a single direction than that of the stem in leaf. In addition, it was considered that the management criteria for objectionable stems should be changed as $3{\times}3$ mm and $2{\times}8$ mm for the $length{\times}thickness$ and $width{\times}length$ sample, respectively, in both steams in leaf and expanded cut-tobacco.

• Resources Recycling
• /
• v.16 no.6
• /
• pp.46-51
• /
• 2007

This study aimed at developing high-efficiency RDF(refuse derived fuels) fuel in order to use RDF energy rationally and to recycle industrial product. As most studies in this area are concentrated in large combustion apparatuses such as kilns, but this study was focused on the small-sized heating systems, applying them directly to grate type boiler which has a heating capacity of $66{\sim}132m^2$. The different kinds of fuel are experimented including RDF. Coke and Waste Tire. First, for this, we experimented and analyzed RDF to see the change in its mass and heating value. Also, four kinds of exhaust gas are sampled by gas analyzer including CO, $CO_2$, NO and $NO_2$ at different temperature. As a result, the levels of CO concentration of RDF are higher than these of coke and waste tire. But, the levels of NO, $CO_2$ and $SO_2$ concentration of RDF and coke were lower then the levels when waste tire is burned.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.5
• /
• pp.165-172
• /
• 2021

The purpose of this study is to investigate the carbon capture capacity of various inorganic materials. For this purpose, the change in property of ordinary Portland cement (OPC), blast furnace slag fine powder (GGBS), and circulating fluidized bed boiler ash (CFBC) due to carbonation were analyzed. Carbonation curing was performed on all specimens through the accelerated carbonation experiment, and the amount of carbon capture was quantitatively analyzed by thermogravimetric analysis according to the age of carbonation. From the results, it is confirmed that the carbon capture capacity was shown in all specimens. The carbon capture amount was shown in the order of CFBC, OPC, and GGBS. The 28-day carbon capture of CFBC, OPC, and GGBS was 3.9%, 1.3%, and 9.4%, respectively. Carbon capture reaction occurred rapidly at the beginning of carbonation, and occurred slowly with increasing age. SEM image analysis revealed that an additional product generated by carbonation curing in all specimens was calcium carbonate.