7 research outputs found

    Stabilization of persistent organic pollutants (POP) in flue gases in a biological waste incinerating facility

    Get PDF
    ArticleThe article focuses on a technology of flue gases stabilization in biological and hospital waste incinerating facility. Hazardous particles and compounds formed in flue gas during the process of thermal waste degradation need to be stabilized according to an enacted legislation. The aim of the research is to examine technological process of polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD/F) elimination in flue gas. PCDD/F is group of persistent organic pollutants which are resistant to environmental degradation and are highly toxic for the environment in very small amounts. Experiments were performed in semi operation hospital waste incinerating plant with heating power 1.5 MW and capacity 250 kg h - 1 of incinerating material. It was observed that formation of PCDD/F exponentially grows with increasing concentration of chlorides in the flue gas, but formation varies based on type of congener. The highest concentration was measured for HxDF, 17,522 pg Nm - 3 and HpDF, 16,334 pg Nm - 3 at chloride concentration of 867 mg Nm - 3 . However, concentration of PCDD congeners didn ́t exceeded 4,000 pg Nm - 3 for the same level of chlorides in flue gas. Two types of activated carbon Chezacarb and NORIT were tested for capability to stabilize PCDD/F in flue gas. Results show that refining effect for both sorbent are very similar. It was observed that 0.1 g of activated carbon should be applied per 1 Nm 3 of flue gas in regard to reduce 3 – 4 ng Nm - 3 PCDD/F under required emission limit

    Energy valorisation of citrus peel waste by torrefaction treatment

    Get PDF
    ArticleThe article deals with th e issue of processing and utilization of citrus peel, which often ends unused with other biodegradable waste. The research is concerned with the energy potential of this raw material and its torrefaction conversion. The tested materials were orange peel ( C itrus sinensis Osbeck cv 'Valencia', Citrus sinensis Osbeck cv 'Murcia') and grapefruit peel ( Citrus paradise 'Ruby red'). Samples of dried materials underwent torrefaction treatment at 225 °C , 250 °C and 275 °C for 30 minutes. Samples before and after tor refaction were analysed for proximate and elemental composition and for calorific value. Consequently, stoichiometric combustion analyses were done. The torrefaction was performed in a LECO TGA 701 thermogravimetric analyzer under nitrogen atmosphere. The results of proximate and elemental analysis showed positive influence of torrefaction on the samples. The highest net calorific value for orange peel is 24.97 MJ kg - 1 at the temperature of 275 °C . The greatest differences in net calorific values are betwee n 225 °C and 250 °C where the increase is almost 3 MJ kg - 1 . Subsequently, the increase between the 250 °C and 275 °C torrefaction temperatures is 1 MJ kg - 1 . Weight loss at respective torrefaction temperatures showed similar time - dependent curves for all sa mples. Stoichiometric combustion analysis shows slight differences between original samples, but great differences after torrefaction processing. Stoichiometric combustion parameters also change proportionately with increasing temperature of torrefication. The resulting comnbustion balance figures show significantly lower need for mass of fuel in the case of the torrefied material for a given heat output thanks to the net calorific value being nearly doubled

    Specialty types of waste paper as an energetic commodity

    Get PDF
    ArticleThe collection and recycling rate of paper and paper packaging material has been on a rise. From 2010 to 2016 in Czech Republic, the recycled amount of all paper went up by 32%, while the share of energy use in waste paper utilization decreased f rom 5.5% to 3.8%. However, not every paper and cardboard product can be recycled, and some are rejected from the recycling stream. Recycling specialty types of paper with other grades of recyclable paper is often not possible and their production is not hi gh enough for their separate recycling to be feasible. If material utilization is not feasible then within the waste hierarchy the next best treatment is their energy utilization. Therefore, this article evaluates selected types of specialty paper for thei r energy content. They were silicone coated papers, polymer coated papers, and paper cores. For all samples proximate, elemental and calorimetric analyses were determined and based on them stoichiometric combustion calculations were performed. Silicon coat ed papers fared generally well having small to reasonable ash content 1 – 10% and net calorific value from 15.10 to 17.10 MJ kg - 1 on dry basis. Polymer coated papers had ash content around 6% and net calorific value from value from 16.29 to 22.98 MJ kg - 1 on dry basis. With the exception of paper cores and self - copying paper, all evaluated paper types could be recommended as a component in refuse derived fuels. The least suitable samples were paper cores with nearly 20% wt. of ash and net calorific value 12.45 MJ kg - 1 on dry basis

    Hydrothermal carbonization and torrefaction of cabbage waste

    Get PDF
    ArticleIn recent years, waste biomass has been increasingly becoming an energy source. The utilization of biomass includes a number of potential treatments: thermochemical, physicochemical and biochemical. In the food industry, significant amounts of biodegradable wastes are produced which have to be quickly treated to not pose an environmental problem. In this work cabbage waste (Brassica oleracea var. capitata) was treated by hydrothermal carbonization and torrefaction. Hydrothermal carbonization experiments were carried out in a pressure reactor vessel Berghof BR-300 (inner volume 400 mL, temperature regulation by Berghof BTC 3000). The carbonization took place at target temperatures 180 °C and 225 °C. Torrefaction tests were carried out in a thermogravimetric programmable oven LECO TGA701 under nitrogen atmosphere at temperatures 225 °C, 250 °C and 275 °C. The residence time was 30 min for both processes. Proximate and elemental composition, as well as calorific value was analysed in all samples. To express the influence of the treatments on combustion behaviour, stoichiometric combustion calculations were performed. The analyses show a positive effect of both torrefaction and hydrothermal carbonization on fuel properties in the samples. Most obvious is the reduction in oxygen content which depends on the process temperature. After hydrothermal carbonization at 225 °C the oxygen content was lowered by 46.7%. The net calorific value increased proportionally with temperature in both processes. After hydrothermal carbonization at 225 °C the net calorific value increased on average by 3 MJ kg-1 to 20.89 MJ kg-1 . Both tested processes significantly increased the fuel value of this biodegradable waste

    Evaluation of dried compost for energy use via co-combustion with wood

    Get PDF
    ArticleThere is still a question of utilization of compost of unsatisfactory quality. This article deals with energy utilization of untreated compost. The energy utilization of raw compost as a fuel is not directly possible without further processing. Separation might be necessary due to large amount of mineral content (soils and other inert substances). This article is focused on the analysis of the basic fuel characteristics of compost. Proximate and elemental analyses were performed and stoichiometric combusti on was calculated. Finally, the sample was co - burned with wood biomass in a fixed grate combustion device and the gaseous emissions were determined in dependence on the amount of combustion air supplied. The emissions were expressed in graphs against exces s air coefficient and flue gas temperature. Elemental analysis of the compost sample shows high percentage of ash up to 61.70% wt. on dry basis causing low average calorific value of 8.51 MJ kg - 1 on dry basis. For combustion tests, the heating value was in creased by addition of wood chips to reach an average calorific value of the mixture to 13.4 MJ kg - 1 . The determined stoichiometric parameters can help in optimization of diffusion controlled combustion of composts or similar materials. In combustion of th e mixture of compost and wood biomass an optimum of emission parameters was found not exceeding the emission limits. Measured emission concentrations show the possibility of optimizing the combustion processes and temperatures while lowering CO emissions v ia the regulation of combustion air
    corecore