AN EXERGY ANALYSIS FOR MINERAL CARBONATION

Magnesium oxide-based minerals such as serpentine and olivine may be used for long-term storage of CO2, from combustion of fossil fuels or industrial processes such as steel works, in the form of magnesium carbonate. Large resources of suitable minerals appear to exist in Finland and at many other locations worldwide. The efficiency of the mineral carbonation process can be evaluated using exergy analysis, which will allow for comparing different mineral deposits that are characterised by different composition and quality. Other factors that play a role are the temperature and pressure, the presence of other gases besides CO2 and the degree of magnesium carbonation that is reached. Important for the analysis is the calculation of the standard chemical exergy of the chemical species involved

POTENTIAL CONTRIBUTION OF ENERGETIC USEFUL DOMESTIC WASTE TO THE ENERGY SUPPLY OF LITHUANIA

The energy potential of domestic waste in Lithuania is 1411 GWh annually. In the case of the introduction of an extensive material recycling of the domestic waste, this amount would be reduced to 727 GWh per annual. Two variants of thermal waste treatment processes were taken into consideration: incineration by great furnaces and gasification followed by the incineration in gas power plants. The calculation of the necessary capacities for the thermal treatment of the domestic waste of every district is based on the annual availability of the plants of 75 %. Finally 4 scenarios arise, considering both the incineration on grate furnaces and the gasification in combination with the current energy potential of domestic waste and the potential after the introduction of extensive material recycling possible in the future

INFLUENCE OF THE REORGANIZATION OF ENERGY INFRASTRUCTURE TO AIR POLLUTION IN THE BALTIC STATES

Prognosis of environmental quality in Baltic states related with the closure of Ignalina Nuclear Power Plant according to two electricity production scenarios was made. (Scenario 1 - closure date of Block 1 is 2005, closure date of Block 2 is 2011; Scenario 2 - closure date of Block 1 is 2005, exploitation of Block 2 will be extended at least until 2020.) We can see that in accordance with both scenarios CO2 an SO2 emission will increase every year. Although the influence of the largest air pollution sources such as Estonian/Baltic PP, Lithuanian PP Riga CHP and others remains very significant to the situation in Baltic States, new power plants will forward the rise of total emission

Household packaging waste management

Household packaging waste (HPW) has an important environmental impact and economic relevance. Thus there are networks of collection points (named “ecopontos” in Portugal) where HPW may be deposited for collection by waste management companies. In order to optimize HPW logistics, accurate estimates of the waste generation rates are needed to calculate the number of collections required for each ecoponto in a given period of time. The most important factors to estimate HPW generation rates are linked to the characteristics of the population and the social and economic activities around each ecoponto location. We developed multiple linear regression models and artificial neural networks models to forecast the number of collections per year required for each location. For operational short term planning purposes, these forecasts need to be adjusted for seasonality in order to determine the required number of collections for the relevant planning period. In this paper we describe the methodology used to obtain these forecasts.This research has been partially supported by COMPETE: POCI-01-0145-FEDER007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

Crystallization of multicrystalline silicon from reusable silicon nitride crucibles: Material properties and solar cell efficiency

In this paper experimental results on High Performance multicrystalline silicon ingots (HPmc-Si) grown from reusable silicon nitride crucibles are presented. Five ingots are grown from the same crucible and the material is analyzed for carbon and oxygen, and metallic impurities, by means of Fourier transform infrared (FTIR) spectroscopy and Neutron Activation Analysis (NAA), respectively. Microwave Photoconductance Decay (μW-PCD) and Quasi-Steady-State Photoconductance (QSSPC) is applied on samples to reveal the resulting charge carrier lifetime distribution. Full-area aluminum back surface field (BSF) solar cells are processed from 156 mm × 156 mm wafers and the solar cell efficiency is analyzed. Material properties and solar cell efficiencies are comparable to reference material grown from high purity electronic grade (EG) quartz crucibles. Obtained results are discussed with respect to results published recently

Development of Technological Line for Solid Recovered Fuel Production and Its Utilization in the Cement Industry: the Case Study of Lithuania

This experimental research was purposed to investigate the production and energy potential of solid recovered fuel (SRF), obtained by extraction of prohibited materials, shredding and drying, from refuse-derived fuel (RDF) to use as an alternative fuel in the cement industry of Lithuania. The characteristics of the obtained RDF by separating the biological fraction from the mainstream of municipal solid waste (MSW) have been determined and compared with the criteria set by developing countries. According to EN15359, currently available RDF can't be called SRF and used as an alternative fuel in a cement kiln. The SRF production line by adding six additional technological units to the existing MBT line was developed. The calculation of the SRF production line was carried out and made 1.89 t/h. At the end of the production process of SRF from RDF, the moisture content (MC) of the obtained SRF decreased by 90 %. After the drying stage, the volume of SRF decreased by 19 %. The process of preparing SRF allowed increasing the net calorific value (NCV) by 22.1 % to 28.2 MJ/kg by reducing the MC. The obtained SRF had a high NCV, low MC, permissible Cl and Hg contents. Two scenarios of waste generation in the Alytus region until 2030 have been developed. Based on the waste generation scenarios results, the proposed SRF production line will provide 12 % of the additional fuel for clinker firing during the analyzed period. A cost analysis to assess the economic and environmental savings from the use of SRF was performed. The results showed that adding 12 % of SRF as a replacement fuel, equal to 1.86 t/h, to the coal used in the cement kiln would save 860 USD/h in coal costs. At the same time, it will emit 5.96 t/h of CO2 into the atmosphere, and the net savings will amount to 1,131 USD/h