• Journal of Korean Society of Environmental Engineers
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• v.31 no.1
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• pp.21-28
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• 2009

Physico-chemical characteristics of the Ca-based and Na-based dry sorbents were compared using thermo-gravimetric analysis (TGA) and temperature programmed desorption (TPD) methods. The studied characteristics were thermal stability, sulfur dioxide ($SO_2$) absorption capacity and absorption rate at $250^{\circ}C$ which is a typical temperature before a fabric filter, and $SO_2$ absorption capacity at an ambient temperature. Calcium hydroxide ($Ca(OH)_2$) started to decompose into calcium oxide (CaO) at $390^{\circ}C$ and completed at 480~$500^{\circ}C$, showing 76% of an original $Ca(OH)_2$ weight. Sodium bicarbonate ($NaHCO_3$) also converted to sodium carbonate ($Na_2CO_3$) between $95^{\circ}C$ and $190^{\circ}C$, decreasing the weight to 63% of its initial weight. Among four sorbents tested at $250^{\circ}C$, sodium carbonate had the highest capacity, absorbing 0.35 g $SO_2$/g sorbent. Calcium oxide and calcium hydroxide followed that showing 0.156 g and 0.065 g $SO_2$ absorption per absorbent respectively. Ca-based absorbents showed slower rate than sodium carbonate because of initial stagnant step. However, calcium hydroxide caught more $SO_2$ than sodium carbonate at ambient temperature. From this work, it can be concluded that Ca-based absorbent is a proper sorbent for $SO_2$ treatment at low temperature and sodium carbonate, at high temperature.

• KSBB Journal
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• v.14 no.1
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• pp.45-50
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• 1999

This study was focused on investigating the growth properties of a sulfate reducing bacterium Deslfovibrio sp. B5 which has metabolic ability for desulfurization of petroleum. The optimal temperature and pH for growth of Desulfovibiro sp. B5 were $38^{\circ}C$ and 6.6-7.0, respectively. Addition of 10% corn steep liquor to the Postgate medium C resulted in 0.79 g/L cell concentration, corresponding to a 1.8-fold increase in dry cell mass. Acetate concentrations above 10g/$\ell$ inhibited cell growth significantly. $H_2S$ generated from the sulfate reduction also inhibited the growth of Desulfovibrio sp. B5 at a concentration of 10mM total sulfide. But $N_2$ gassing relieved the growth inhibition by $H_2$S and thereby resulted in a 1.75-fold enhancement in specific growth and lactate consumption pattern of Desulfovibrio sp. B5.

• Journal of ILASS-Korea
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• v.14 no.1
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• pp.1-7
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• 2009

This study carried out numerical analysis of flow field of combustion gas and sorbent to test sorbent efficiency of DSI process. To provide rapid mixing for increase utilization rate of sorbent, streamwise vorticity can be introduced into the flowing streams by other means; for example, by installing vortex generators immediately downstream of the wavy trailing edge. Computing results show that the degree of sorbent dispersion depends strongly on duct structure. Highest dispersion efficiency received when vortex generator was installed inside of duct. The results presented in this study a optimum condition for the development of practical DSI process.

• Journal of Industrial Technology
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• v.15
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• pp.175-185
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• 1995

Under the new environmental regulations announced by the government, utilities will have to cut their sulfur dioxide emissions by 60% from 1991 levels by the year of 1999. Sulfur dioxide emissions can be reduced prior to combustion by physical, chemical or biological coal cleaning. The new technology of high gradient magnetic separation (HGMS) offers the potential of economic separatoins of a variety of fine, weakly magnetic minerals including inorganic sulfur and many ash-forming minerals from coals. In the present paper, magnetic separation tests have been conducted on Korean anthracite and high-sulfur Chinese coal to investigate the feasibility of these techniques for reducing sulfur content from coals. In wet magnetic separation, the studied operating parameters include particle size, pH, matrix types, feed solids content, feed rate, number of cleaning stages and etc. The results shows that for wet separation, 60~70% of total sulfur was removed from coals with over 80% combustible recovery, on the other hand, for dry separation, 47.6% of total sulfur was removed from coals with 75% recovery.

• KSBB Journal
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• v.14 no.3
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• pp.380-383
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• 1999

During the biodesulfurization of dibenzothiophene to 2-hydroxybiphenyl by Rhodococcus erythropolis IGTS8, a surfactant-like substance was secreted into the medium resulting in the decrease of the surface tension of the medium. Due to the substance, the optical density (at 600 nm) of the medium had no co-relation with dry cell weight during cultivation. The growth rate of IGTS8 increased by the addition of 1 % Tween 80, but it was inhibited over Tween 80 concentration of 2 % (v/v).

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.81-87
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• 2006

In marine air pollution control, SCR (Selective Catalytic Reduction) is reconized as the most effect method to control NOx, but on the other hand. seawater scrubber applying the basic characteristic that is naturally alkaline (pH typically around 8.1) is viewed as an economical SOx removal system at present. Especially, seawater scrubber would not be necessary to follow any of the various land based flue gas desulfurization methods. i.e. wet, dry or alkali scrubbing. However, these methods are not readily adaptable to marine conditions due to the quantifies of consumables required i.e. lime or limestone, the means of operation and the commercial availability. This research is undertaken to develop a new method as the main target of eliminating all exhaust emissions, particularly vessel, because of easy access to seawater and apt to apply a wet scrubber system. First, using the acidic seawater by seawater electrolysis, nitric monoxide(NO) is adequately oxidized to nitric dioxide $(NO_2)$by ClOx-in the acidic seawater, the electrolyzed alkaline seawater by electrolysis which contains mainly NaOH together with alkali metal ions $(i.e\;Na^{+}\;K^{+},\;Mg_{2}\;^{+},\;Ca_{2}\;^{+})$, is used as the absorption medium of NOx, the SOx are absorbed by relatively high solubility compared to other components of exhaust pollutants. The results found that the NOx and SOx removals could be achieved nearly Perfect.

• Journal of the Korean Society of Safety
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• v.14 no.1
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• pp.78-85
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• 1999

The removal characteristics of H$_2$S from IGCC process over the natural manganese ore(NMO) containing several metal oxides($MnO_x$ : 51.85%, $FeO_y$ : 3.86%, CaO : 0.11%) were carried out in a batch type fluidized bed reactor(I.D.=40mm, height=0.8m). The $H_2S$ breakthrough curves were obtained as a function of temperature, initial gas velocity, initial gas concentration, and aspect ratio. The effect of particle size ratio and particle mixing fraction on $H_2S$ removal were investigated with binary system of different particle size. From this study, the adsorption capacity of $H_2S$ increased with temperature but decreased with excess gas velocity. The breakthrough time for $H_2S$ is reduced as the gas velocity is increased which leaded to gas by-passing and gas-solid contacting in a fluidized bed reactor. The results of the binary particle system with different size in batch experimental could predict to improve the behavior of continuous process of $H_2S$ removal efficiency. The natural manganese ore could be considered as potential sorbent in $H_2S$ removal.

• Journal of the Korea Institute of Building Construction
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• v.17 no.6
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• pp.507-515
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• 2017

This study is to develop a high quality lightweight foamed concrete that can be applied in the field using EXFG by cracking reducing agent combined with FGD and ALS. First, to increase the volume of foam, the flow and density of the mixture was increased and decreased, respectively. At this time, the effect of substitution ratio of EXFG on fluidity was negligible. The fraction of foam was the highest at EXFG 1%, and the settlement was found to be prevented by the expansion reaction at EXFG 1%. At this time, the ratio of foam was 65%. In the compressive strength, the strengths were similar or decreased when the substitution ratio of EXFG was more than 1%. The apparent density satisfied the KS 0.5 type at the bubble contents was 65%. In case of EXFG substitution, dry shrinkage was decreased by about 10%. As the substitution ratio of EXFG increased, the thermal conductivity increased proportionally.

• Clean Technology
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• v.2 no.1
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• pp.80-95
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• 1996

A mathematical model has been developed for simulating the spray dryer absorber (SDA) used in semi-dry flue gas desulfurization process. Fundamental equations include the component mass and heat balances in both gas and droplet phases and the equation of motion for a single droplet. The model developed described the pilot-plant data much better than the existing SPRAYMOD-M model. The effect of the process variables, whose values were chosen within the operation limits of the actual pilot plants, on % $SO_2$ removal or conversion of the sorbent were calculated, and discussed in terms of $SO_2$ absorption rate, the residence time of flue gas, the velocity and drying time of droplets. Finally, the % $SO_2$ removal was calculated with two independent process variables and the results were shown on three-dimensional or two-dimensional diagrams with the lines of constant % $SO_2$ removal, so that they can be easily applied to preliminary design of the SDA.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.2
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• pp.57-66
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• 2019

This study carried out on-site investigation and precision monitoring to prepare proper design and operation technical guidelines for the use of bio gas in organic waste resources (fertilizing urine, food waste, food waste, food waste, etc.). According to the government's mid- and long-term policy on bio gasification, the expansion of waste resources is actively being pushed forward. However, facilities that use the biogas produced for urban gas and transportation are still under-efficient. Precision monitoring was carried out for biogasification facilities of organic waste resources in seven locations nationwide. When the results of precision monitoring were summarized with the four-season average, the efficiency analysis of each organic waste resource showed that the organic breakdown rate was 66.3% on average on VS basis. Analysis of biogas characteristics before and after pretreatment revealed that the $H_2S$ average of the entire facility was measured at 949.7 ppm using iron salts and desulfurization (dry, wet) and that the quality refining facility shearing and rear end was 29.0 ppm and 0.3 ppm. The methane content was found to be reduced by 65.6% at the rear of the fire tank, 63.5% at the back and 97.5% at the rear.