• Resources Recycling
• /
• v.23 no.1
• /
• pp.40-47
• /
• 2014

Feasibility of utilizing unburned carbon residue in coal ash as a potential precursor for the production of activated carbon was assessed to seek for solution to recycle unburned carbon residue. The unburned carbon concentrate generated from the 4 stages of cleaner flotation has a grade of 87% carbon. The crystalline impurities in the concentrate included quartz and mullite. Unburned carbon had a low specific surface area of $10m^2/g$, which might be related to a high degree of coalification of domestic anthracite coal. Carbon particles were mostly porous and have a turbostratic structure. When 1g of carbon was activated with 6g of KOH powder, the highest specific surface area value of $670m^2/g$ was achieved. Low wettability of unburned carbon particles, which was resulted from high temperature combustion in a boiler, might cause poor pore formation when they were activated by KOH solution. The activated carbon produced in this study developed micropores, with an equivalent quality of general-purpose activated carbon made from coal. Hence, it is concluded that chemically treated unburned carbon can be used for water purification or an alternative to carbon black as it is.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.15 no.3
• /
• pp.106-112
• /
• 2007

The purpose of this study is to derive the mixing ratio with stable heating value to be used as fuel and secondary fuel by mixing sewage sludge cake, tar, peat moss, and verify the combustion property of produced solid fuel and the applicability of RDF as alternative fuel. Tar shows the highest heating value with 7,000kcal/kg and the heating value of sewage sludge cake and peat moss ranges from 4,000 to 4,500kcal/kg. Also, the solid fuel with length 1.6cm, diameter 1.3cm and weight 2.3g was produced using the heating value of over 6,000kcal/kg and proper mixing ratio (sewage sludge cake: tar: peat moss) from 1 : 4 : 1 to 1 : 7 : 1. Upon the analysis of the RDF applicability of produced solid fuel, the exhaust gas analysis finds that the composition concentration of exhaust gas occurred according to the mixing ratio did not change significantly and the flame lasting time was found to be around 5 minutes, similar to the lasting time of the same mass (2.3g) of general anthracite burned. Therefore, it can be concluded that solid fuel produced in this study can be used as fuel and secondary fuel.

• Journal of Korean Society for Atmospheric Environment
• /
• v.33 no.6
• /
• pp.570-582
• /
• 2017

In recent years, national and local government's air quality management and climate change adaptation policy has been significantly strengthened. The measures in the two policies may be in a relationship of trade-off or synergy to each other. Greenhouse gases and air pollutants are mostly emitted from the same sources of using considerable amounts of fossil fuels. Co-benefits, in which either measure has a positive effect on the other, may be maximized by reducing the social costs and by consolidating the objectives of the various policies. In this study, the co-benefits were examined by empirically analyzing the effects of air pollutants and greenhouse gas emission reduction, social cost, and cost effectiveness between the two policies. Of the total 80 projects, the next 12 projects generated co-benefits. They are 1) extend restriction area of solid fuel use, 2) expand subsidy of low-$NO_x$ burner, 3) supply hybrid-vehicles, 4) supply electric-vehicles, 5) supply hydrogen fuel cell vehicles, 6) engine retrofit, 7) scrappage of old car, 8) low emission zone, 9) transportation demand management, 10) supply land-based electric of ship, 11) switching anthracite to clean fuel in private sector, 12) expand regional combined-energy supply. The benefits of air pollutants and greenhouse gas-related measures were an annual average of KRW 2,705.4 billion. The social benefits of the transportation demand management were the highest at an annual average of KRW 890.7 billion, and followed by scrappage of old cars and expand regional combined-energy supply. When the social benefits and the annual investment budgets are compared, the cost effectiveness ratio is estimated to be about 3.8. Overall, the reduction of air pollutants caused by the air quality management policy of Gyeonggi-do resulted in an annual average of KRW 4,790.2 billion. In the point sources management sector, the added value of $CO_2$ reduction increased by 4.8% to KRW 1,062.8 billion, while the mobile sources management sector increased by 3.6% to KRW 3,414.1 billion. If social benefits from $CO_2$ reduction are added, the annual average will increase by 7.2% to KRW 5,135.4 billion. The urban and energy management sectors have shown that social benefits increase more than twice as much as the benefits of $CO_2$ reduction. This result implies that more intensive promotion of these measures are needed. This study has significance in that it presents the results of the empirical analysis of the co-benefits generated between the similar policies in the air quality management and the climate change policy which are currently being promoted in Gyeonggi-do. This study suggested that the method of analyzing the policy effect among the main policies in the climate atmospheric policy is established and the effectiveness and priority of the major policies can be evaluated through the policy correlation analysis based on the co-benefits. It is expected that it could be a basis for evaluation the efficiency of the climate change adaptation and air quality management policies implemented by the national and local governments in the future.

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.11
• /
• pp.989-996
• /
• 2009

In this study, the effects of biofilter media type (three different activated carbons and anthracite), empty bed contact time (EBCT) and temperature on the removal of four aldehyde species (formaldehyde, acetaldehyde, glyoxal and methylglyoxal) in BAC filters were investigated. Experiments were conducted at three water temperature (5, 15 and $25^{\circ}C$) and four EBCTs (5, 10, 15, and 20 min). The experimental results indicated that the coal based BAC retained more bacterial biomass on the surface of the activated carbon than the other BACs, and increasing EBCT or increasing water temperature also increased the four aldehyde species removal in BAC filters. To achieve above 80% of removal efficiency for four aldehyde species in a BAC filter, above 15 min EBCT at $5^{\circ}C$ and 10 min EBCT at above $15^{\circ}C$ were required. The kinetic analysis indicated a first-order reaction rate for the biodegradation of four aldehyde species at various water temperatures. Data obtained from the BAC filters at various temperatures were also used to evaluate pseudo first-order rate constants for four aldehyde species. The half-lives evaluated for formaldehyde, acetaldehyde, glyoxal and methylglyoxal in the coal-based BAC ranging from 0.89 to 3.19 min, from 0.75 to 3.35 min, from 2.16 to 4.72 min and from 1.49 to 3.86 min, respectively, could be used to assist water utilities in designing and operating BAC filters.

• Korean Journal of Soil Science and Fertilizer
• /
• v.29 no.3
• /
• pp.236-242
• /
• 1996

This study was conducted to investigate the changes of heavy metals in percolated water of paddy soil in which rice was cultivated in conditions of 0%, 5%. 30% addition of bituminous and anthracite fly ash respectively. In cultivated plot, the contents of Fe in percolated water increased gradually during the cultivation. But there was no sharp difference of Fe contents in fly ash treated plots. The contents of Mn in percolated water increased gradually during the cultivation and was high in the cultivated plot. But difference in the contents of Mn among plots not clear. The contents of Zn in percolated water was highest during 20-25 days in the cultivation, thereafter decreased gradually. The fly ash did not cause to increase the contents of Zn in percolated water. The contents of Cu in percolated water decreased through the cultivation. Fly ash treatment did not cause to increase the contents of Cu in percolated water. The contents of Pb in percolated water decreased gradually over the cultivation. Fly ash treatment did not largely influence to Pb percolation. In mid-July. Pb did not almost appeared in percolated water. The contents of Cd was highest about 15 days of the transplant, thereafter decreased gradually. After 40 day of the cultivation, leach of Cd stopped. When fly ashes were applied in paddy soil, the contents of heavy metals in percolated water was not so much compared with control plot. It seems that originally low contents of heavy metals in fly ash and decrease in solubility of heavy metals in a relatively high soil pH make it possible to use fly ash as a soil conditioner.

• Journal of Preventive Medicine and Public Health
• /
• v.18 no.1
• /
• pp.1-11
• /
• 1985

A decade ago a survey on the population-base incidence rate of anthracite coal gas (mainly carbon monoxide) poisonig in Seoul area was investigated, resulting in the incidence rate of 306/10,000 risk population and 1 death/10,000. Another survey on the carbon monoxide poisoning was investigated during 1 year period from Apr. 1983 to Mar. 1984. Total subjects of risk population were 67,740 households covering 353,287 persons. The major findings of this survey are as follows: 1. Household-base incidence rate was 8.4% spell-base 10.4%. 2. The incidence rate was the highest in houses having each of slate roof, cement wall, vinyl floor of bedroom and direct 'ondol' heating system. 3. Average 2.1 person was attacked from one incidence of the poisoning; severity-wise person-base incidence rates per 10,000 were 352 in mild poisoning, 54 in severe poisoning and 1.4 in death-overall incidence rate 407. Several facts were identified which supported that this figure was moderately underestimated. As the incidence of the poisoning is affected by socioeconomic and environmental factors, it is natural that one expects the incidence will decrease in proportion to genernal improvement of the above factors. Thus the results of these two surveys seemed preposterous. But further study suggested that the incidence rate (306/10,000) decade before had been significantly underestimated and corrected-rate should have been 478/10,000 level. 4. Age and sex distribution by the degree of the poisoning was uniform with little statistical difference; overall incidence rates by sex were 339/10,000 in male and 475/10,000 in female with significant statistical difference(p<.01). 5. 5.3% of the patients were treated at hospital or local clinic; 3.0% of the patients were hospitalized. Admission rate in comatose patient(severe poisoning) was 14.2%. In conclusion, carbon monoxide poisoning remains a major health problem by now.

• Korean Chemical Engineering Research
• /
• v.49 no.1
• /
• pp.114-119
• /
• 2011

Thermogravimetric analysis(TGA) was carried out for pyrolysis and char-$CO_2$ gasification of low rank Indonesian ABK coal and China lignite. The pyrolysis rate was successfully described by a two-step model adopting the modified Kissinger method. The shrinking core model, when applied to char-$CO_2$ gasification gave initial activation energy of 189.1 kJ/mol and 260.5 kJ/mol for the ABK coal and China lignite, respectively. Thus, the char-$CO_2$ gasification has been successfully simulated by the shrinking core model. In particular, the activation energy of char-$CO_2$ gasification calculated in this work is similar to the results on the anthracite coal, but considerable difference exists when other models or coal types are used.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.6
• /
• pp.318-324
• /
• 2017

We evaluated geosmin and MIB biodegradation and adsorption mechanism of biological activated carbon (BAC) and anthracite biofilter. In steady state of BAC process, the geosmin and MIB were completely removed at the 30 min empty bed contact time (EBCT) even though low water temperature ($9^{\circ}C$) in which the activity of attached bacteria decreased. When the water temperature was $26^{\circ}C$, the microbial biomass and activity were higher at the upper layer of the biofilm than at $9^{\circ}C$, and the microbial biomass and activity decreased as the depth was deeper. This is because when the water temperature is high, the biodegradable organic matter (BOM) removal rate in the upper layer is high and the BOM amount that can't be supplied to the lower layer. The Removal rate of geosmin and MIB by BAC process did not show a significant difference compare to activity-inhibited BAC by treated with azide and the biofilter also removed the geosmin and MIB by biological action. It means geosmin and MIB could be removed by competitive relationship between adsorption and biodegradation.

• Applied Chemistry for Engineering
• /
• v.8 no.2
• /
• pp.179-190
• /
• 1997

To study the effects of chemical composition on the fusion temperatures of coal ashes, the chemical composition, mineral matter, and fusion temperature were studied with 54 kinds of coal ash samples including Korean anthracite coals. CaO, MgO and $Fe_2O_3$ were observed to be major fluxing elements in reducing and oxidizing atmosphere. The fluxing effect of $Fe_2O_3$ was increased more in reducing atmosphere. In a base/acid ratio, the fusion temperature decreased with increasing amounts of basic components. Nevertheless, the correlation between a fusion temperature and base/acid ratio was not shown well in a higher ratio of $Fe_2O_3/CaO$. The differences of fusion temperatures between oxidizing and reducing atmosphere showed close relationship with $SiO_2/Al_2O_3$ ratio rather than with $Fe_2O_3$ contents. Multiple regression was used to predict the fusion temperature of coal ashes, and it was established that the major predictors in oxidizing atmosphere were Base/Acid, $Fe_2O_3/CaO$, $SiO_2/Al_2O_3$, and $(SiO_2/A1_2O_3){\cdot}(Base/Acid)$ and Base/Acid, $Fe_2O_3/CaO$, $SiO_2$, and $TiO_2$ were major ones in reducing atmosphere.

• Journal of Preventive Medicine and Public Health
• /
• v.17 no.1
• /
• pp.5-24
• /
• 1984

There has been an immense need for elaborate studies on the complications and the neuological sequelae generated by acute carbon monoxide (CO) poisoning which is highly prevalent in Korea due to widespread adoption of the anthracite coal briquette as domestic fuel for heating and for cooking. For this epidemiological study, a total of 444 subjects who received hospital emergency care for acute CO poisoning during the period of March 1982 to February 1983 were randomly selected from the emergency patients's lists of 13 general hospitals in Seoul area. Informations on the neurological sequelae were elucidated by means of home visiting with prearranged questionnaire consisting questions and concise neurological examination. The findings obtained were summarized as follows; 1. The complications were found in 18% of the surveyed and acute decubitus was comprised 67.5% of the complications. 2. The total cumulative incidence of the neurological sequelae was 41.2 per 100 patients and the absolute incidence rate regardless of the duration after poisoning was 40.8%. 3. The incidence of the neurological sequelae was higher in the older age than in the younger and also higher in female than in male. Twice higher incidence was observed in the admitted patients than in the non-admitted patients and the incidence became higher in proportion to the duration of CO exposure, coma and admission. The poorer the consciousness level of patients found, at emergency room and at discharge, the higher the incidence. The incidence of the neurological sequelae by emergency care was higher in hyperbaric oxygen therapy group(51.9%) than in 100% $O_2$ group(38.0%) 4. A total of five variables significantly associated with the occurrence of the neurological sequelae were selected by the stepwise discriminant analysis. The variables were following course of emergency care, age, consciousness level at discharge, admission duration, and consciousness level at emergency room in their sequence of discriminant power. Eight variables were selected as those associated with the degree of the neurological sequelae through the stepwise multiple regression analysis. Of these variables, the acute decubitus alone explained 21.1% of the total variation ana all the eight variables could explain 36.5% of the same. The remaining seven variables listed in the order of their relative importance were: age, consciousness level at discharge, admission duration, coma duration and consciousness level at emergency room. 5. It was postulated that unexpectedly high incidence of the neurological sequelae of the CO poisoning in this epidemiological study was mainly due to the inadequate emergency care and the lack of efficient and sophisticated treatment measure. In the effort to minimize the incidence of grave neurological sequelae of acute CO poisoning, new guidelines for the emergency care and treatment should be pursued with efficient ways.