Factors Determining the Element Behavior in Municipal Solid Waste Incinerators. 2. Laboratory Experiments

Abstract

Laboratory experiments with synthetic samples are conducted to obtain information on the evaporation behavior of metals in incinerators. In combining the results obtained through field measurements presented in a companion paper in this issue, hypotheses are postulated on the influence of physical and chemical conditions as well as of kinetics on the evaporation behavior of the chosen elements in the furnace bed. These are validated by thermal treatment of bottom ash samples in the laboratory. A temperature increase of from 500 °C to 900 °C causes higher transfers of most metals into the gaseous phase. Mo and Sb are the exceptions. Chlorine availability generally favors evaporation. Increasing oxidative conditions cause lower Sn transfers. Transfer of the elements Cd, Mo, Sb, Sn, and Zn is negatively affected by their reaction with reaction partners other than oxygen and chlorine occurring in municipal solid waste. Oxidation of organic carbon to CO and CO2 as well as HCl formation determine the distribution of temperature, redox conditions, and chlorine availability in the furnace bed. First indications are obtained on the residence times of goods under these different local conditions. The knowledge acquired can be used to design new incinerators with “tailor-made” products that can either be recycled or landfilled without an adverse environmental impact for the long term. For this purpose, mechanical processing techniques, thermal treatments at temperatures between 500 °C and 1100 °C, and high-temperature treatments (>1100 °C) including melting processes will have to be combined.

Persistence of engineered nanoparticles in a municipal solid-waste incineration plant

“…A few attempts have been made to investigate individual flue gas cleaning steps, such as the electrostatic precipitator 12 , or to model the release of engineered nanoparticles from incineration to air 13 . However, because waste incinerators are complex systems that include interaction effects arising from heterogeneous waste matrices and changing process conditions, any model predictions and laboratory studies are of limited value and require verification by large-scale experiments 14,15 . We demonstrate this necessity for large-scale experiments through an additional set of small-scale ones, in which we account for the incineration behaviour of different size classes of engineered nanoparticles.…”

Online elemental analysis of process gases with ICP-OES: A case study on waste wood combustion

“…Strong correlations in elemental concentrations were found among sodium, potassium and zinc against chlorine for feedstock W2. Others have reported similar findings (Poole et al, 2007;Khan et al, 2009;Jakob et al, 1996;Belevi and Langmeier, 2000;Struis et al, 2004). Under the given conditions of combustion below 1000°C and chlorine contents of at least 0.3% in the feedstock, the dominant species of alkali emissions is expected to be potassium chloride (Khan et al, 2009;Monkhouse, 2002).…”

“…To determine the elemental compositions of strongly heterogeneous waste streams such as waste wood requires extremely laborious procedures. In the literature it has therefore also been proposed to characterize feedstocks by their ashes (Belevi and Moench, 2000;Belevi and Langmeier, 2000;Morf et al, 2000).…”

“…Under the given conditions of combustion below 1000°C and chlorine contents of at least 0.3% in the feedstock, the dominant species of alkali emissions is expected to be potassium chloride (Khan et al, 2009;Monkhouse, 2002). Alkalis have been ascribed a carrier function for chlorine (Monkhouse, 2002), and chlorine in turn has a well-documented carrier function for the volatilization of metals (Khan et al, 2009;Struis et al, 2004;Belevi and Langmeier, 2000;Jakob et al, 1996). Two mechanisms involving chlorine can lead to a concurrent mobilization of alkalis and metals.…”

Partitionings and Kinetic Behaviors of Major-to-Ultratrace Elements between Industrial Waste Incineration Fly and Bottom Ashes as Studied by ICP-AES and ICP-MS

“…So far, a number of investigations have been performed to elucidate the elemental behaviors during the incineration processes of waste materials in full-scale plant experiments [6][7][8][9][10] as well as in pilot-scale plant experiments and the laboratoryscale experiments. [11][12][13][14] In general, the behaviors of the elements in waste incinerators are influenced by various factors, as follows: (i) the distributions of elements in input waste materials; (ii) the temperatures, redox conditions, and contents of the reaction partners, such as chlorine in the furnace bed; and (iii) the residence time and mixing conditions in the furnace bed. Some theoretical approaches have been also made to predict the elemental behaviors in incinerators.…”