In the process of creating sustainable heat and power production systems it is important to find alternative, renewable fuels that are carbon dioxide neutral. Preferably these fuels should be domestic, thus diminishing the need for transportation. One option could be to use existing residues from local agriculture and food production. Development of combustion methods suitable for such residues is presently being pursued by a number of companies. Because many biomass fuels have compositions that makes them inclined to cause ash sintering problems and emissions of acid gases, there may be a need for the use of additives to decrease such problems. The aim of this work was to examine the ash characteristics of some agricultural crops and residues and to find mixtures of fuels and additives that can form the basis for production of fuel pellets with minimal problems. The work is focused on biomass fuel pellets for small-scale grate-fired combustors. Three additives (limestone powder, kaolin, and sodium bicarbonate) were investigated regarding their effects on the ash melting behavior. The results show that calcium carbonate and kaolin both serve as good additives to prevent the formation of slag. The best antislagging effect was achieved when both additives were used. Sodium bicarbonate can be used as a sulfur binding additive, but this cannot be recommended since it increases the slag formation considerably. The conclusion is that combustion of agricultural crops and residues may be hampered by problems such as slag formation and ash fouling. However, through the use of suitable additives, the ash sintering characteristics can be improved significantly. This means that agricultural residues can be competitive fuels on the energy market in the future.

No abstract

Abstract. This paper describes the new developments of the Ship Traffic Emission Assessment Model (STEAM) which enable the modelling of pollutant discharges to water from ships. These include nutrients from black/grey water discharges as well as from food waste. Further, the modelling of contaminants in ballast, black, grey and scrubber water, bilge discharges, and stern tube oil leaks are also described as well as releases of contaminants from antifouling paints. Each of the discharges is regulated by different sections of the IMO MARPOL convention, and emission patterns of different pollution releases vary significantly. The discharge patterns and total amounts for the year 2012 in the Baltic Sea area are reported and open-loop SOx scrubbing effluent was found to be the second-largest pollutant stream by volume. The scrubber discharges have increased significantly in recent years, and their environmental impacts need to be investigated in detail.

No abstract

No abstract