Young-Soon Baek

Highly stable Ni catalyst supported on Ce-ZrO2 for oxy-steam reforming of methane

A novel catalyst, Ni/Ce–ZrO2, exhibits very high catalytic activity and stability even in the stoichiometric steam reforming of methane (H2O/CH4 = 1). Furthermore, when it was employed in oxy-steam reforming, it gave enhanced CH4 conversion (99.1%) at 750 °C and the activity was maintained for 100 h. The high catalyst stability is mainly ascribed to the synergistic effect of the Ce modifier resulting from high capacity to store oxygen and high ability to produce mobile oxygen.

Thermodynamic design data and performance evaluation of the water + lithium bromide + lithium iodide + lithium nitrate + lithium chloride system for absorption chiller

Abstract Duhring (P–T–X) and enthalpy-concentration (H–X–T) diagrams of the H2O + LiBr + LiNO3 + LiI + LiCl (mole ratio of LiBr : LiNO3 : LiI : LiCl = 5 : 1 : 1 : 2) system were constructed by using the experimental data sets. Thermodynamic design data for a double-effect series-flow absorption chiller were calculated at various operating conditions [ 2≤Te≤14°C, 30≤Ta≤50°C, 30≤Tc≤50°C, T gh COP =0 ≤T gh ≤T gh (crystallization limit)] by a computer simulation. The proposed working fluid was found to be applicable to cycle operation of air-cooled absorption chiller with no crystallization problem at higher absorber temperature.

Solubilities, Vapor Pressures, and Heat Capacities of the Water + Lithium Bromide + Lithium Nitrate + Lithium Iodide + Lithium Chloride System

The optimum mole ratio of lithium salts in the H2O + LiBr + LiNO3 + LiI + LiCl system was experimentally determined to be LiBr : LiNO3 : LiI : LiCl = 5 : 1 : 1 : 2. The solubilities were measured at temperatures from 252.02 to 336.75 K. Regression equations on the solubility data were obtained with a least-squares method. Average absolute deviations of the calculated values from the experimental data were 0.15% at temperatures <285.18 K and 0.05% at temperatures ≥285.18 K. The vapor pressures were measured at concentrations ranging from 50.0 to 70.0 mass% and at temperatures from 330.13 to 434.88 K. The experimental data were correlated with an Antoine-type equation, and the average absolute deviation of the calculated values from the experimental data was 2.25%. The heat capacities were measured at concentrations from 50.0 to 65.0 mass% and temperatures from 298.15 to 328.15 K. The average absolute deviation of the values calculated by the regression equation from the experimental data was 0.24%.

Development of a catalytic burner with Pd/NiO catalysts

Abstract A catalytic burner was studied which can be used as a heater operated at medium temperature. The catalytic combustion was initiated by an igniter which was placed on the exit surface of the catalyst layer. Noble metal catalysts (Pd/NiO) which were supported on alumina washcoated honeycomb were used, whose maximum heat-resisting temperature is about 900°C. The optimal operating conditions for stable catalytic combustion were obtained by means of analyzing the catalytic combustion region, the temperature distribution, and the combustion efficiency.

The conversion of natural gas to higher hydrocarbons using a microwave plasma and catalysts

Methane, the major constituent of natural gas, had been converted to higher hydrocarbons by a microwave plasma. The yield of C2+ products increased from 29.2% to 42.2% with increasing the plasma power and decreasing the flow rate of methane. When the catalysts were used in the plasma reactor, the selectivities of ethylene and acetylene increased while the yield of C2+ remained constant. Among the various catalysts used, the Fe catalyst showed the highest ethylene selectivity of 30%. When we introduced the actual natural gas, more C2+ products were obtained (46%). This is due to the ethane and propane in the natural gas. When an electric field inductance for evolving the high plasma was applied, a high yield in C2+ products of 63.7% was obtained for the Pd-Ni bimetal catalyst.

A DIRECT CATALYTIC CONVERSION OF NATURAL GAS TO C2+ HYDROCARBONS BY MICROWAVE PLASMA

Methane, the major constituent of natural gas, was converted to higher hydrocarbons by a microwave plasma. The yield of C2+ products increased from 29.2 % to 42.2% with increasing plasma power and decreasing flow rate of methane. When catalysts were used in the plasma reactor, the selectivities of ethylene and acetylene increased, while the yield of C2+ remained constant. Among various catalysts used, Fe catalyst showed the highest ethylene selectivity of 30 %. And when the actual natural gas was introduced, more C2+ products were obtained (46%). This is due to the ethane and propane in the natural gas. Applying electric field inductance for evolving the high plasma, we obtained high C2+ products of 63.7 % when Pd-Ni bimetal catalyst was used.

Optimization of KOGAS DME Process From Demonstration Long-Term Test

Dimethyl ether (DME) is a new clean fuel as an environmentally-benign energy resource. DME can be manufactured from various energy sources including natural gas, coal, and biomass. In addition to its environmentally friendly properties, DME has similar characteristics to those of LPG. The aim of this article is to represent the development of new DME process with KOGAS`s own technologies. KOGAS has investigated and developed new innovative DME synthesis process from synthesis gas in gaseous phase fixed bed reactor. DME has been traditionally produced by the dehydration of methanol which is produced from syngas, a product of natural gas reforming. This traditional process is thus called the two-step method of preparing DME. However, DME can also be manufactured directly from syngas (single-step). The single-step method needs only one reactor for the synthesis of DME, instead of two for the two-step process. It can also alleviate the thermodynamic limitations associated with the synthesis of methanol, by converting the produced methanol into DME, thereby potentially enhancing the overall conversion of syngas into DME. KOGAS had launched the 10 ton/day DME demonstration plant project in 2004 at Incheon KOGAS LNG terminal. In the mid of 2008, KOGAS had finished the construction of this plant and has successively finished the demonstration plant operation. And since 2008, we have established the basic design of commercial plant which can produce 3,000 ton/day DME.

An Electrochemical Study on the Carbon Black Conductor Prepared by Plasma Pyrolysis of Methane

Plasma carbon black(PB) which prepared by plasma pyrolysis of methane was treated at 800, 1300 and under torr. Four different samples including raw PB were added to , cathode active material of lithium secondary battery, to investigate effects of properties of plasma black as conductors on electrochemical characteristics. Based on our experimental results, PB conductors with low amount of surface functional groups and high electrical conductivity enhanced the cyclability and the initial discharge capacity. However, deterioration of rate capability and cyclability were observed (or the plasma black treated at For the plasma black conductor prepared from plasma pyrolysis, the effects of properties of carbon black on electrochemical characteristics were combined results of changes in electrical conductivity and structural properties such as agglomeration of plasma black. The conductivity of plasma black increased with treatment temperature, while dispersion of plasma black decreased. As a result, the high cyclability of cell was observed at of heat treatment temperature.

Surface tensions and thermal conductivities of aqueous LiBr-based solutions containing n-octanol and 2-ethyl-1-hexanol: Application to an absorption heat pump

Surface tensions and thermal conductivities were measured for LiBr+1,3-propanediol+water and LiBr+LiI+1,3-propanediol+water. These two mixtures were chosen as one of the potential candidates for working fluids for absorption heat pumps. Surface tensions and thermal conductivities were measured by the capillary rise method equipped with a cathetometer and the transient hot wire method with a coated tantalum wire, respectively. The measured surface tension and thermal conductivity data were well correlated with a simple polynomial function of temperature and absorbent concentration. In addition, the surface tensions of LiBr+1,3-propanediol+water containing a small amount of alcohol-based surfactants, n-octanol and 2-ethyl-1-hexanol, were also measured at 298.15 K by the ring method. An increase in the surfactant concentration up to about 500 ppm leads to a gradual decrease in the mixture surface tensions.

Gasification Characteristics of Pinus rigida (Pitch Pine) and Quercus variabilis (Oriental Oak) with Dolomite Catalyst in a Fluidized Bed Reactor

In this study, coniferous (pitch pine, Pinus rigida) and broad-leaved (Oriental oak, Quercus variabilis) trees were gasified in a bubbling fluidized bed reactor, and the effects of reaction temperature and catalyst species on product yields and selectivities were systematically investigated. Upon increasing the gasification temperature from 800 to 900°C, the gas yield of P. rigida maintained similar values at 75.15–78.41%, while the gas yield of Q. variabilis decreased from 71.05 to 58.15% and the char and oil yields increased. The composition of gaseous products was affected according to catalyst species. When dolomite-based catalysts were used for fog biomass gasification, the hydrogen fraction increased substantially, while the carbon monoxide fraction decreased.