Teruel Power Station Research Articles

Utilization of zeolites synthesized from coal fly ash for the purification of acid mine waters.

Two pilot plant products containing 65 and 45% NaP1 zeolite were obtained from two Spanish coal fly ashes (Narcea and Teruel Power Station, respectively). The zeolitic product obtained showed a cation exchange capacity (CEC) of 2.7 and 2.0 mequiv/g, respectively. Decontamination tests of three acid mine waters from southwestern Spain were carried out using the zeolite derived from fly ash and commercial synthetic zeolite. The results demonstrate that the zeolitic material could be employed for heavy metal uptake in the water purification process. Doses of 5-30 g of zeolite/L have been applied according on the zeolite species and the heavy metal levels. Moreover, the application of zeolites increases the pH. This causes metal-bearing solid phases to precipitate and enhances the efficiency of the decontamination process.

Sources of natural and anthropogenic sulphur around the Teruel power station, NE Spain. Inferences from sulphur isotope geochemistry

Stable sulphur isotopic ratios were used for the identification of sources of atmospheric sulphur compounds, and the assessment of their contribution to the atmospheric sulphur deposition load around a coal-fired power plant in NE Spain. The study consists of a number of stages: identification of the sources, clarification of the chemical pathways of the sulphur from these sources, assessment of their contribution to the overall load, and determination of the emission impact on the natural sulphur cycle in the area. Sulphur isotope analyses were carried out on bedrock and sediment samples, surface and groundwater, wet-only and total deposition, total suspended particles and SO 2 emissions from the power plant. The results are useful in indicating the sources of sulphate in the atmosphere, allow us to exclude some other potential sources, and demonstrate that: (a) the total load of sulphate is largely unaccounted for by Cl and is, therefore, of non-sea spray origin; (b) this excess sulphate does not originate from bedrock and sediments in the area; (c) there is a significant contribution of sulphur from remote sources such as the Atlantic–north European areas; (d) the multitude of local and remote sources involved and the rapid change in their relative contribution do not facilitate the quantification of the deposition derived from the emissions of the power station. However, given the low conversion efficiency and the relative constancy of the δ 34S of the emitted SO 2 it is suggested that sulphate deposits with δ 34S of around 2.5‰ originate from the Teruel power station.

Characterisation of atmospheric particulates around a coal-fired power station

The present work focuses on the characterisation of total suspended particulates (TSP) around the Teruel power station in NE Spain with special emphasis on sulphate aerosols due to their acidification potential. The specific objectives are the determination of the seasonal evolution of TSP levels and chemistry, and investigation of possible neutralisation processes for acidic aerosols in the atmosphere. Concentrations of the elements studied in TSP show a marked seasonal trend in the study period (July 1995 to July 1997) characterised by higher levels in spring–summer and relative low levels in autumn and winter. In the case of sulphate aerosols, this pattern may be attributed to higher SO 2 oxidation in the summer and autumn, and to the higher frequency of impact of the emission plume on the surface in this period. A seasonal trend of SO 2 oxidation rates is also found. The soil-related elements show a similar seasonal trend which is interpreted to be a consequence of the typical Mediterranean atmospheric dynamics (Sahara air mass intrusions, convective dynamics, and low precipitation scavenging during summer.) In addition to seasonal variations, a clear grain-size fractionation is observed for the different ions determined. SO 4 2− and NH 4 + are concentrated in the finest grain-size fraction, while NO 3 −, Cl −, K +, Mg 2+, Na + are concentrated in relatively coarser fractions, and Ca 2+ levels increase with the particle diameter. Neutralisation of sulphate acidic aerosols is carried out by NH 4 + and minor amounts of Ca 2+. The sulphate neutralising compounds are described by different analytical methods.

Daily evolution of sulphate aerosols in a rural area, northeastern Spain—elucidation of an atmospheric reservoir effect

The present work is focused on the daily evolution in the levels and composition of total suspended particles and PM10 (particulate matter <10 microns) in rural areas around the Teruel power station in northeastern Spain, with special emphasis on sulphate aerosols. A daily cycle in the levels of natural and sulphate aerosol is evidenced by higher ratios of sulphate/soil elements during the diurnal stage when compared with the nocturnal period. The origin of this cycle is probably related to higher SO 2 oxidation rates and a higher frequency of plume impacts on the surface during the diurnal period. However, this trend is frequently disturbed by local atmospheric dynamics which give rise to an atmospheric reservoir of sulphate aerosols which increase nocturnal sulphate levels without major SO 2 plume impacts. These atmospheric dynamics are described in spring, summer and winter measurement campaigns which are characterised by different plume dispersion scenarios. The results indicate that the three following situations concerning the sulphate levels can be present in the study area: (1) direct plume impacts inducing high sulphate levels in short time periods; (2) a sulphate reservoir effect leading to relatively high sulphate background levels, homogeneously distributed at distances of 60 km from the power plant, without major SO 2 impacts; and (3) a regional sulphate background giving rise to relatively low sulphate levels with a clear external origin and seasonal trend.

Seasonal evolution of suspended particles around a large coal-fired power station: particulate levels and sources

The present work focuses on the seasonal evolution of suspended particles (TSP and PM10) around the Teruel power station in NE Spain. The specific objectives are the determination of the spatial and time variability of levels of suspended particles, and their relationship with the power plant emissions and other natural or anthropogenic (local or external) particulate sources. The results show a marked seasonal trend, along the study period (July 1995–August 1996) which is characterized by particulate levels that were higher in spring–summer and decreased progressively towards winter. This trend may be related to (a) higher summer oxidation which increased levels of secondary particles, (b) higher convective circulation in summer which raised levels of soil-related particles and anthropogenic particles, (c) higher frequency of intrusion episodes of Sahara air masses in summer and spring, and (d) lower aerosol scavenging potential in summer. The similarity between the seasonal evolutions of daily mean levels of SO2 and particulates is due to the fact that both are partially controlled by the solar cycle. The long range transport particulate inputs affecting this area of the Mediterranean Basin (mainly Sahara air mass intrusions) account for major particulate peaks recorded at the monitoring stations. The influence of the emissions from the power plant in the PM10 and TSP levels is evidenced only in periods with a low background particulate levels. The results demonstrate that even PM10 levels are still highly influenced by the Saharian and European particulate inputs. Therefore, for an accurate environmental assessment, probably PM2.5 should be monitored instead of TSP or PM10, in order to quantify the influence of the power plant emissions on the bulk atmospheric particulate levels. The results obtained from the air back-trajectory analysis and their comparison with the time series of daily PM10 levels allowed the classification of the major external particulate inputs as a function of the particulate levels.

Seasonal evolution of suspended particles around a large coal-fired power station: Chemical characterization

Abstract The present work focuses on the seasonal evolution of total suspended particles (TSP) around the Teruel power station in Northeastern Spain. The results show a marked seasonal trend, along the sampling period (July 1995–July 1996), which is characterized by levels of the elements studied in TSP that were higher (up to one order of magnitude) in spring-summer and decreased progressively towards winter. This trend contrasts with the seasonal evolution reported by most of the studies carried out in industrial and urban areas in Central and Northern Europe. The origin of this seasonal TSP trend may be related to: (a) higher summer oxidation which increased levels of secondary TSP; (b) higher convective circulation in summer which raised levels of soil-related particles and primary anthropogenic particles; (c) higher frequency of intrusion episodes of Sahara air masses in summer and spring; and (d) lower aerosol scavenging potential in summer. A clear grain-size fractionation was observed for the different ions determined. SO 4 2− and NH 4 + were concentrated in the finest grain-size fraction (0.3−0.6 μm); NO 3 −, Cl −, K +, Mg 2+, Na + and minor amounts of NH 4 + were concentrated in the 1.2−5.0 μm fractions; and Ca 2+ increased with the particle diameter. S-bearing species were (NH 4) 2SO 4 (mascagnite), (NH 4) 2Ca(SO 4) 2 · H 2O (koktaite) and CaSO 4 · 2H 2O (gypsum). Mascagnite was the dominant species in the finest grain size fraction (0.3−0.6 μm), whereas koktaite was also present in the 0.6−1.2 μm fraction, and gypsum predominated in the other fractions.

Use of coal fly ash for ceramics: a case study for a large Spanish power station

Ceramic products with up to 50 wt% of mullite and 16 wt% of feldspars were obtained from binary mixtures of fly ash from the Teruel power station (NE Spain) and plastic clays from the Teruel coal mining district. The firing behaviour of fly ash and the ceramic mixtures was investigated by determining their changes in mineralogy and basic ceramic properties such as colour, bulk density, water absorption and firing shrinkage. To determine the changes on heating suffered by both the fly ash and the ceramic bodies, firing tests were carried out at temperatures between 900 and 1200°C in short firing cycles. The resulting ceramic bodies exhibit features that suggest possibilities for use in paving stoneware manufacture, for tiling and for conventional brickmaking.

Synthesis of zeolites by alkaline activation of ferro-aluminous fly ash

Zeolites were synthesized from fly ash by alkaline hydrothermal activation. High-Fe fly ash from the Teruel power station in NE Spain was the starting material. The activation was performed by 0.1 M NaOH and KOH solution in a closed system. Zeolite formation was studied as a function of temperature (60 and 150°C), reaction time (24, 168 and 336 h) and sample/solution ratio (30, 60, 100 and 200 gl −1). The zeolitic products synthesized were phillipsite, merlinoite, analcime, zeolite Na-P1 and nosean. Other reaction products identified were portlandite and bayerite. The activated material in the fly ash was mainly glass and quartz. The highest zeolite synthesis efficiency was 75%.

The behaviour of mineral matter during combustion of Spanish subbituminous and brown coals

AbstractCombustion experiments up to 1400°C were carried out with subbituminous coals from the Teruel power station, the Teruel Mining District, the Santa Eulalia coal deposit and with lignite from the As Pontes power station in Spain. The characterisations of the occurrence and distribution of inorganic matter and its transformation during combustion of these coals were carried out by means of X-ray diffraction and optical and electron microscopy. The combustion experiments show that the incorgainc transformations during the combustion of all the coals studied vary depending on the sulphur and calcium contents. The sulphur, iron and calcium contents govern the quality of anhydrite crystallisation (which takes place between 600 and 900°C Furthermore, the high calcium oxide content produces the fouling of the combustion wastes at relatively low temperatures (1200°C), prevents the occurrence of mullite and magnetite in the ashes and leads to the crystallistation of anorthite and esseneite during the colling. The comparison of the inorganic phases of fly ashes and slags from the Teruel power station with those of the experimental wastes shows that the inorganic transformations during coal combustion in the power station can be predicted by means of laboratory furnace experiments provided that the residence time in the flame and the effect of the cooling and evacuation controls of gases and particles from the power station are taken in consideration.