Coal-burning Power Plants Research Articles

COLOR REMOVAL FROM PULP MILL EFFLUENT USING COAL ASH PRODUCED FROM GEORGIA COAL COMBUSTION PLANTS

In this study, Coal Fly Ash (CFA), a byproduct of coal combustion power plants, was used as an adsorbent to remove color from locally-obtained pulp mill effluent (PME). Batch adsorption studies were conducted to determine the adsorption parameters that would result in the maximum color removal from PME at the lowest CFA dosage and process cost. The effects of operating variables on color removal were studied by varying: 1) CFA dosage, 2) initial PME pH, and 3) contact time. The findings indicate that the optimum CFA dosage for cost-effective color removal was 100.0 g/L (80.5% removal) given an initial effluent color concentration below 900 mg/L Pt-Co color units. For effluent samples with a color concentration over 900 mg/L Pt-Co color units, the optimum CFA dosage was 250.0 g/L (80.4% removal). In addition, no pH adjustment of the PME was required for maximum color removal. A kinetic study showed that color removal by CFA occurred rapidly in the first hour, and adsorption equilibrium was achieved at 24 hours. Additionally, the kinetic and isotherm adsorption data was best described by the Ho et al. kinetic model and the Langmuir and Freundlich isotherm models, respectively. Overall, this research found CFA to be a promising low-cost adsorbent for the removal of color from PME.

POTENSI PEMANFAATAN LIMBAH PEMBAKARAN BATUBARA (BOTTOM ASH) PADA PLTU SEBAGAI MEDIA TANAM DALAM UPAYA MENGURANGI PENCEMARAN LINGKUNGAN

The impact of environmental pollution is now beginning to perceive by all levels of humans and in the world such as global warming, until climate change has inspired the research on the utilization of waste coal combustion (Bottom Ash) power plant. This research uses Bottom Ash (BA) from PLTU (Electric Steam Power Plant) Suralaya, by choosing Selada (Lactuca sativa), Sawi (Ipomea Autica), and Kangkung (Brassica rapa var). Percentage BA used as planting media is 0%, 25%, 50%, 75%, and 100%. BA serves to accelerate the process of rupture and plant growth due to the availability of Ca, Mg, Na, K, N, P, S and Fe elements. Planting media for Lettuce plant species is 25%. The corresponding percentage of BA as planting media for Plant Sawi species is 25%, and 50%. While in the Kangkung plant BA percentage that is suitable for use as a planting media is 25%, 50%, and 75%. The apparent anomaly at this test are Kangkung percentage 75% and Lettuce50%, 75% stems become longer, and leaves become slightly even in 100% Bottom Ash percentage, Lettuce grows with smaller size/dwarf. The amount of nutrient excess need to be accurately measured through laboratory test first. With further testing it is hoped that the utilization of coal ash waste (Bottom Ash) becomes more real and effective as a growing media seen from risk and danger aspects.

Advantages of switching coal-burning power plants to coal-water slurries containing petrochemicals

Enterprises from chemical, oil-processing, transport, energy, and other industries are struggling to reduce their negative environmental impact without sacrificing the profit. The main negative impact comes from the anthropogenic emissions (NOx, SOx, CO2, and fly ash) from the combustion of coal, oil products, and other fuels. Coal is regarded as the most environmentally hazardous one. An advanced solution to the environmental problems of coal-burning enterprises is switching from coal to fuel slurries containing water and waste flammable liquids. These are known as coal-water slurries (CWS) or coal-water slurries containing petrochemicals (CWSP). In this research, we analyze all the main strengths and weaknesses of high-potential CWS and CWSP fuels as compared to coal. For the evaluation we use such indicators as heat of combustion and fuel consumption; anthropogenic emissions and ash residue; maximum combustion temperature; minimum ignition temperatures; ignition delay times; cost of components; feasibility indicators of storage, transportation, and combustion of fuels; fire and explosion safety. We also introduce a complex parameter to consider the contribution of all the above indicators. The research findings are consolidated with due consideration of high-potential components for CWSP fuels, their properties and concentrations.

Identification of waste management strategies and waste generation factors for thermal power plant sector wastes in Turkey.

Thermal power plants are of great environmental importance in terms of the huge amounts of wastes that they produce. Although there are process-wise differences among these energy production systems, they all depend on the logic of burning out a fuel and obtaining thermal energy to rotate the turbines. Depending on the process modification and the type of fuel burned, the wastes produced in each step of the overall process may change. In this study, the most expected process and non-process wastes stemming from different power generation processes have been identified and given their European Waste Codes. Giving priority to the waste minimization options for the most problematic wastes from thermal power plants, waste management strategies have been defined. In addition, by using the data collected from site visits, from the literature and provided by the Turkish Republic Ministry of Environment and Urbanization, waste generation factor ranges expressed in terms of kilogram of waste per energy produced annually (kg/MWh) have been estimated. As a result, the highest generation was found to be in fly ash (24-63 for imported coal, 200-270 for native coal), bottom ash (1.3-6 for imported coal, 42-87 for native coal) and the desulfurization wastes (7.3-32) produced in coal combustion power plants. The estimated waste generation factors carry an important role in that they aid the authorities to monitor the production wastes declared by the industries.

Fly-ash as a low-cost material for isolation of phosphoproteins

Metal oxide affinity chromatography (MOAC) is one of the most commonly used techniques for selective isolation phosphoproteins and phosphopeptides. This technique is capable of capturing the phosphorylated biomolecules through the affinity of the phosphoryl group for metal oxides/hydroxides. Fly-ash (FA), a by-product of coal-combustion power plants, is primarily composed of oxides of silicon and metals, among which iron and titanium. A number of studies have demonstrated the potential of these metal oxides for phosphoprotein and phosphopeptide enrichment. FA is annually produced over hundred million tons worldwide and generally considered as hazardous waste. It is thus of great importance to enhance its utilization. Here we present the first demonstration of the utility of FA as a low-cost MOAC material for the enrichment of phosphoproteins. With an FA-microcolumn, phosphoproteins can be successfully sequestered from other proteins. FA-microcolumns are shown to be simple, cheap and selective devices for phosphoprotein enrichment from a small volume of mixtures.

The Impact of Coal-Powered Electrical Plants and Coal Ash Impoundments on the Health of Residential Communities.

BACKGROUND In North Carolina, coal-burning power plants remain the major source of electrical production. Coal burning generates coal ash that is stored in landfills and slurry ponds that are often located near residential communities, signifying high potential for environmental contamination and increasing health risks. We reviewed the literature on potential health effects of coal-burning plants to summarize current knowledge on health risks.METHODS We searched English-language publications issued between January 1, 1987, and December 31, 2017, on PubMed and Google Scholar.RESULTS The algorithm of identification, screening, eligibility, and inclusion/exclusion we used provided 113 peer-reviewed publications selected for the review. Over the past 30 years, scientists reported that the people living in close proximity to coal-fired plants had higher rates of all-cause and premature mortality, increased risk of respiratory disease and lung cancer, cardiovascular disease, poorer child health, and higher infant mortality. The elevated health risk was associated with exposure to air pollutants from the power plant emissions and to a spectrum of heavy metals and radioactive isotopes in coal ash.CONCLUSION In North Carolina, further studies are required to profile the severity of the cumulative impacts of multiple air, water, and soil contaminants related to coal-burning power plants and coal ash impoundments on human health and the environment. Prioritized study directions on evaluation of health impacts of coal-burning power plants in North Carolina are suggested.

Carbonation of high-calcium fly ashes and its potential for carbon dioxide removal in coal fired power plants

Carbonation of industrial wastes rich in earth-alkali oxides is found to have a significant potential for CO2 sequestration. This process opens new perspectives not only for carbon dioxide mitigation, but also for the valorization and new applications of industrial waste materials from coal-burning power plants. In this study, mineral carbonation of high–calcium fly ash is investigated under dry and moist conditions in a continuous flow reactor during up to 2 h, at temperatures ranging from 160 to 290 °C and CO2 pressures between 1 and 6 bar. A comprehensive characterization of treated and untreated samples was carried out before and after carbonation using X-ray diffraction, X-ray fluorescence spectroscopy, thermogravimetric analysis, infrared spectroscopy and scanning electron microscopy. The maximum sequestration capacity achieved was 117.7 g CO2/kg fly ash (48.14% carbonation efficiency) under dry conditions. Results showed that increasing the pressure and temperature enhances the process of carbonation, as well as the presence of moderate amounts of water vapor in the CO2 gas flow. Newly formed carbonates were always present in the treated samples. This study shows that about 21% of all CO2 emissions of a coal-burning power plant could potentially be sequestered as carbonates.

Administrating Violence through Coal Ash Policies and Practices

Coal ash, the waste generated at coal-burning power plants, is one of the largest waste streams in the United States, and it contains a range of contaminants, including arsenic and mercury. Disasters at coal ash waste sites in recent years have led to increased public scrutiny of coal ash in communities and have sparked policy debates, lawsuits, and complaints throughout the country. With emphasis on federal and state coal ash policies since the 1970s, this article highlights the synthesis of government and corporate power in coal ash politics, and the bureaucratic processes affecting communities near coal ash sites. Based on ethnographic research following the 2008 Tennessee Valley Authority coal ash disaster, as well as preliminary research on the “social life” of coal ash in North Carolina, this article specifically offers ethnographic insight into the lived experiences of social and ecological violence created, perpetuated, and normalized through bureaucratic processes.

Immobilization of Fluorine Using a Dolomite Geochemical Barrier

The possibility of using the dolomite geochemical barrier for fine cleaning of alkaline wastewaters against fluorine was substantiated in experiments for coal-burning power plants. It was found that the residual fluorine concentration at pH 10.4–10.6 conformed to the optimum values for potable waters (0.7–0.9 mg/L), whereas the degree of fluorine removal at pH > 12.0 was at a maximum at 99.2% with less than 0.1 mg/L residual fluorine concentration. The optimum residual concentration of fluorine was obtained under the stoichiometric excess of dolomite over reactive CaO in ashes and slag wastes, which allowed calculation of the required capacity of dolomite barriers.

Lower beryllium exposure limit to be required in May

The U.S. Occupational Safety & Health Administration will begin enforcing a final rule limiting occupational exposure to beryllium in general industry, construction, and shipyards on May 11, two months later than planned. Airborne beryllium damages workers’ lungs through exposure from a host of activities: foundry and smelting operations, fabricating, machining, grinding beryllium metal and alloys, ceramics manufacturing, and dental lab work. Beryllium exposure is also a concern for people handling fly ash residue from coal-burning power plants and in the construction and shipyard industries. The final rule replaces a 40-year-old exposure limit that was outdated and did not adequately protect worker health, OSHA says. OSHA formally began a rule-making process in 2002 and proposed a rule in 2015. Once in place, the rule will toughen exposure limits to one-tenth of the current level. OSHA has estimated the rule will save the lives of 94 workers annually. The delay was necessary

Shorter telomere length in cord blood associated with prenatal air pollution exposure: Benefits of intervention

BackgroundTo examine the molecular benefits of the government action to close the local coal burning power plant in Tongliang County, Chongqing Municipality, we compared biologic markers and health outcomes in two successive birth cohorts enrolled before and after the plant was shut down. In this city, polycyclic aromatic hydrocarbons (PAH) were primarily emitted by the coal burning facility. We previously reported that cord blood levels of PAH-DNA adducts (a biomarker of exposure) and various adverse health outcomes were reduced in the second cohort, whereas levels of brain-derived neurotrophic factor/BDNF (a protein involved in neuronal growth) were increased. Here we assessed telomere length (TL), which has been associated with risk of certain chronic diseases, early mortality, aging and cognitive decline in adults. ObjectivesThe goals of the present study were to determine whether TL differed between the two cohorts and whether prenatal PAH exposure, estimated by PAH-DNA adducts in cord white blood cells of newborns in China, were predictive of shorter TL in cord blood, suggesting the potential accrual of risk of certain chronic diseases during the prenatal period. We explored relationships of TL with BDNF and neurodevelopmental outcomes, each previously associated with PAH-DNA adducts in these cohorts, as well as the potential mediating role of TL in the associations between adducts and neurodevelopmental outcomes. MethodsWe analyzed TL in cord blood of 255 newborns who also had data on PAH-DNA adducts, BDNF, and relevant covariates. Multiple regression analysis was carried out to test associations between adducts and TL and between TL and BDNF, adjusting for relevant covariates. In the subset with developmental quotient (DQ) scores from Gesell testing at age 2 (N = 210), we explored whether TL was a mediator of the relationship between PAH-DNA adducts and DQ scores by first examining the associations between cord adducts and DQ, cord adducts and TL, and TL and DQ, adjusting for the same covariates. ResultsAs hypothesized, the mean TL was significantly higher in the second cohort compared to the first cohort. Overall, PAH-DNA cord adducts were significantly and inversely correlated with TL. Multiple regression analysis showed a significant association between adducts and TL, after adjusting for key covariates: β (effect size per standard deviation adducts) = −0.019, p = .003. The regression coefficient of TL on (Ln) BDNF was also significant (β = 0.167, p < .001). Exploratory analysis, regressing TL on Gesell developmental scores, showed generally inverse, but not significant associations. TL was not, therefore, deemed to be a potential mediator of the association between adducts and developmental scores at age two. ConclusionThis study provides the first evidence that prenatal PAH exposure from coal burning may adversely affect TL, with potential implications for future risk of chronic diseases including cardiovascular disease. The improvement in TL in the second cohort and the observed correlation between increased TL and higher levels of BDNF indicate direct benefits to the health and development of children resulting from the government's closure of the power plant.

Assessment of water quality in a coal burning power plant area of Malaysia using multivariate statistical technique

Assessment of water quality in a coal burning power plant area of Malaysia using multivariate statistical technique

Removal of Copper (II) Ions in Aqueous Solutions by Sorption onto Alkali Activated Fly Ash

Fly ash is a particulate material produced from coal combustion power plants with major components are silica, alumina, iron oxide, calcium oxide, magnesium oxide, and carbon which are ideal for metal adsorbents. The potential use of fly ash in the wastewater treatment process is obvious because it can be obtained cheaply in large quatities and it can be used as an adsorbent. However, fly ash still shows lower adsorption capacity unless it is activated. In this study, fly ash activated by NaOH 14 M and KOH 14 M solutions. The batch experiments were carried out to study the sorption of copper ions from aqueous on alkali activated fly ash. The influence of initial concentration and contact time were examined at constant pH and dose of adsorbent. The sorption capacity of copper ions increased with the initial concentration and contact time. The sorption capacities followed the order Na1&gt;Ka1&gt;FA. The adsorption isotherm model exhibited that the Langmuir model is very suitable with copper ions adsorption onto fly ash and alkali activated fly ash. Kinetic study shows that adsorption of copper ions onto FA, Na1, and Ka1 follows the pseudo second-order kinetics.

The Effect of Fly Ash Composition and Drying Time Concrete Brick in Density Test

This study uses the fly ash (FA) from coal combustion power plant Sijantang Sawahlunto. By utilizing fly ash in concrete brick can reduce the negative impact on the environment, composition of fly ash in concrete brick at 0, 5, 10, and 15 wt.% FA concrete brick added material (sand, cement and water as a binder). Influence of drying time 7, 14, 21, 28, and 35 days. Test specimen based on SNI 03-0349-1989, with size of 34 x 12 x 9 cm. The results showed that the composition of 5 wt.% fly ash with 28 days drying time was found to be the highest density with 2,230 gr/cm3, while the lowest density in the composition test was 15 wt.% fly ash with 35 days drying time with the density 1,946 gr/cm3. In this study, the density of normal concrete brick density with density 2,208-2,230 gr/cm3 and light concrete brick density of 2,000-1,946 gr/cm3, and also found a normal and light concrete brick category that is 2,022-2,053 gr/cm3.

Numerical simulation study on different spray rates of three-area water distribution in wet cooling tower of fossil-fuel power station

A coal-burning power plant’s cooling tower can take away about 55% of the heat that the steam absorbs in the boiler, which represents a big energy saving potential. This paper presents a three-dimensional numerical model to analyze the influence of non-uniform water distribution on the cooling performance of a counter-flow wet cooling tower with different spray rates, while providing thermal calculation of a large cooling tower. In addition, the user-defined function in the fill zone is compiled. The heat and mass transfer in the fill zone is solved by UDF. This study covers a three-area water distribution structure in the water distribution system. Cooling tower data verified the accuracy of the model. The influence of the inner, middle and outer areas in relation to their location on the cooling tower and effect on spray rate on the outlet water temperature was investigated in detail. The effect of the three-area water distribution structure on the velocity field, temperature field and the mass fraction of H2O in the tower are analyzed. The water flow rate that makes the temperature drop to its maximum low point has been given. The results show that the outlet water temperature of the tower can be effectively reduced by adopting the three-area water distribution structure and proper water distribution flow. Consequently, it can improve the efficiency of the cooling tower and generate enormous economic benefits.

CO2-free coal-fired power generation by partial oxy-fuel and post-combustion CO2 capture: Techno-economic analysis

Among the carbon capture and storage (CCS) technologies suitable for power generation plants, partial oxy-combustion coupled with post combustion CO2 capture is gaining interest, since such a hybrid configuration could allow to reduce the size and enhance the performance of post-combustion CO2 capture by operating combustion with air enriched with oxygen and reducing the dilution of flue gas. Moreover, partial oxy-combustion is a potential candidate for the retrofit of existing steam plants because it could be based on an almost conventional boiler and requires a smaller CO2 capture section.This work presents the results of a comparative techno-economic analysis of a 1000 MWth partial oxy-combustion plant based on an ultra-supercritical pulverized coal combustion power plant integrated with a post-combustion CO2 capture system and geological storage in saline aquifer. In particular, plant performance is assessed by using simulation models implemented through Aspen Plus 7.3 and Gate Cycle 5.40 commercial tools, whereas economic performance are evaluated on the basis of the expected annual cash flow. The analysis shows that, for new plants, this hybrid approach is not feasible from the economic point of view and full oxy-combustion potentially remains the most profitable technology even if, in the short-term period, the lack of commercial experience will continue to involve a high financial risk.

DOCUMERICA and the Power of Environmental History

DOCUMERICA and the Power of Environmental History

Enzymatic reactive absorption of CO2 in MDEA by means of an innovative biocatalyst delivery system

Due to the increasing world population and industrialization the worldwide energy requirement is also increasing. About 82% of the world’s total primary energy supply stems from fossil sources and coal combustion in power plants accounted for 46% of the 32.4 Gt global carbon dioxide (CO2) emissions in 2014 (International Energy Agency, Key CO2 Emissions Trends: Excerpt from CO2 Emissions from Fuel Combustion (2016 edition)). The reduction of CO2 emissions from power plant flue gases is therefore essential to enable reliable and ecologically benign energy supply.An efficient technology to reduce CO2 emissions is reactive absorption in packed columns with aqueous amine-based absorption solvents, herein also called absorbents. The major drawback of conventional amine absorbents is their high absorption enthalpy, which causes high energy requirements during solvent regeneration. Alternative solvents that offer significantly lower absorption enthalpies suffer from lower absorption rates. To compensate for low absorption rates the enzyme carbonic anhydrase (CA) can be added to the absorbent to accelerate absorption kinetics by catalyzing the reaction between CO2 and water. For industrial applications, it can be desirable to immobilize CA which extends enzyme longevity by confining the enzyme to favorable process conditions, prevents unnecessary exposure to high process temperatures, and enables enzyme reuse.The CO2 absorption characteristics and handling properties of an innovative immobilized CA in the form of microparticles, called biocatalyst delivery system (BDS), were evaluated together with aqueous MDEA solvent. Operational feasibility parameters were validated in lab scale, followed by replicated CO2 absorption performance tests in a small demonstration scale counter-current packed column. A sixfold enhancement in total absorbed mole flow of CO2 in the presence of BDS was demonstrated versus blank MDEA solvent. Recyclability and longevity of BDS were validated.

Converting hollow fly ash into admixture carrier for concrete

This study proposes a low-cost method to convert cenospheres into an admixture carrier for concrete manufacturing. Cenospheres are hollow fly ash particles generated in coal burning power plants, having an aluminosilicate shell with high strength and stiffness. The large inner volume of the cenospheres can be used to carry and release admixtures in concrete. However, directly using cenospheres as the carrier is not possible because the inner pore is not accessible to the admixture. To address this problem, chemical etching is employed to produce perforating holes through the shell. Liquid admixtures can be easily loaded into and later released from the produced perforated cenospheres (PCs). A series of characterization tests were carried out to understand the working mechanism of the chemical etching method and its effect on the properties of the PCs. It has been found that chemical etching dissolved a small amount of amorphous materials from the cenosphere shell. As a result, the cenoshpere shell was weakened, as indicated by the reduction of the bulk crushing strength of the PCs. Nevertheless, the bulk crushing strength of all produced PCs are sufficient to guarantee that they can survive the mixing and initial stress in fresh concrete. To experimentally confirm the feasibility of using the PCs as an admixture carrier for concrete, PCs were added into cement mortar as the internal water carrier, which successfully mitigated the autogeneous shrinkage in a low water-to-cement ratio concrete. Scanning electron microscopy analysis of the cement mortar confirms that PCs not only survived the mixing of concrete, but also were dispersed and bonded well to the cement mortar. This study suggests that PCs may provide a versatile tool to integrate various admixtures in concrete.

Source identification of individual soot agglomerates in Arctic air by transmission electron microscopy

Individual soot agglomerates collected at four different locations on the Arctic archipelago Svalbard (Norway) were characterised by transmission electron microscopy and energy-dispersive X-ray microanalysis. For source identification of the ambient soot agglomerates, samples from different local sources (coal burning power plants in Longyearbyen and Barentsburg, diesel and oil burning for power generation in Sveagruva and Ny Ålesund, cruise ship) as well as from other sources which may contribute to Arctic soot concentrations (biomass burning, aircraft emissions, diesel engines) were investigated.Diameter and graphene sheet separation distance of soot primary particles were found to be highly variable within each source and are not suited for source identification. In contrast, concentrations of the minor elements Si, P, K, Ca and Fe showed significant differences which can be used for source attribution. The presence/absence of externally mixed particle groups (fly ashes, tar balls, mercury particles) gives additional hints about the soot sources.Biomass/wood burning, ship emissions and coal burning in Barentsburg can be excluded as major source for ambient soot at Svalbard. The coal power plant in Longyearbyen is most likely a major source of soot in the settlement of Longyearbyen but does not contribute significantly to soot collected at the Global Atmosphere Watch station Zeppelin Mountain near Ny Ålesund. The most probable soot sources at Svalbard are aircraft emissions and diesel exhaust as well as long range transport of coal burning emissions.