Refuse Derived Fuel Combustion Research Articles

Pyrolysis of plastics-free refuse derived fuel derived from municipal solid waste and combustion of the char products in lab and pilot scales: A comparative study

Pyrolysis of refuse derived fuel (RDF) has great potential for energy recovery from municipal solid waste (MSW), while chlorine-related plastics issue was one major barrier for scale up. After screening out plastics, the RDF pyrolysis and char products combustion were evaluated in lab and pilot scales. Thermogravimetry with Fourier-transform infrared spectroscopy results suggest that the main RDF pyrolysis reaction occurred in 190–410 °C, involving decomposition, decarboxylation, demethylation, and dehydration reactions, with CO2, CH4, H2O, CO, and organic compounds as the main gaseous products. Impacts of temperature and residence time on char yield and proximate composition were evaluated in lab, and a lower temperature was favored. The pilot-scale char had a comparable proximate composition to the lab-scale ones, but a lower heating value, lower H/C ratio, higher O/C ratio, which may due to different dominant reaction pathways during pyrolysis: apparent demethanation versus dehydration. Thermogravimetry data infers that the combustion performance of pilot-scale char, including combustion stage, weight loss, and kinetic parameters, were close to chars made in lab. Pilot-scale combustion tests show relief of flue gas pollution after upgrading RDF to char, while particulate matter and heavy metals were still main concerns. Lab- and pilot-scale investigations highlight scale up of plastics-free RDF pyrolysis and combustion as a promising and economic alternative for materials and energy recoveries from MSW.

Effect of red mud on combustion behavior and heavy metal stabilization of Refuse Derived Fuel (RDF)

Refused Derived Fuel (RDF) from municipal solid waste has become a promising and effective approach for waste storage and utilization. However, the poor combustion performance and heavy metals (HMs) emission limit the development of this technology. In this study, red mud (RM), an industrial waste from the alumina extraction process, was used as an additive to improve the combustion behavior of RDF. The results show that 10 wt% of red mud addition can increase the flammability index (F) and the comprehensive combustion characteristic index (S) by 91% and 156%, respectively. It significantly reduced the burnout temperature of RDF by 59 °C. Moreover, RM also promoted the transformation of HMs into more stable forms. The proportion of F4 speciation for Cr, Ni, Cu, Zn Cd, and Pb in ash residues increased by 6.42%, 50.91%, 92.48%, 43.77%, 15.77%, and 4.53%, respectively, while the leaching rate of Cr, Ni, and Cd decreased by 1.7%, 0.99%, and 1.31%. The findings proved that RM could serve as an efficient additive for enhancing RDF combustion and stabilizing the HMs in ash residues, which would provide new insight into the co-utilization of wastes and the contribution to the clean combustion of RDF.

Effect of granulation on chlorine-release behavior during municipal solid waste incineration.

The preparation of refuse-derived fuel (RDF) is an effective and simple means of rural municipal solid waste utilization. The release of chlorine during RDF combustion is important as it causes high-temperature corrosion and pollutants emission such as HCl, dioxins, etc. In this paper, constant-temperature and increasing-temperature combustion experiments were carried out using an electrically heating furnace to analyse the effects of granulation (pressure and additives) on the release of chlorine in particles. During the constant-temperature combustion below 800 °C, only organic chlorine was released from the RDF. The increase of granulation pressure from 1 MPa to 10 MPa did not affect the total amount of chlorine release, but delayed the organic chlorine release by increasing the gas diffusion resistance. During the constant-temperature combustion above 900 °C, inorganic chlorine was released as well. The increase of granulation pressure enhanced the inorganic chlorine release significantly by promoting the reactants contact. During the increasing-temperature combustion, the increase of granulation pressure delayed the organic chlorine release as well but inhibited the inorganic chlorine release. This was mainly attributed to the slow temperature rise to 900 °C, during which the inherent calcium in the RDF reacted with silicon and aluminium, resulting in less reactants for an inorganic chlorine release reaction. Three calcium-based additives were used to inhibit chlorine release. CaCO3 showed no dechlorination effect, and CaO showed better dechlorination effect than Ca(OH)2. For the constant-temperature combustion at 900 °C, the addition of CaO with a Ca/Cl ratio of 2 achieved a dechlorination efficiency of over 90%, with little influence from the granulation pressure. For the increasing-temperature combustion, the granulation pressure had a significant influence on CaO dechlorination effectiveness. Only at a granulation pressure as high as 10 MPa, did the addition of CaO with the Ca/Cl ratio of 2.5 achieve a dechlorination efficiency of 95%.

EXPERIMENTAL INVESTIGATION OF OXYFUEL COMBUSTION OF RDF AND WOOD CHIPS IN A GRATE INCINERATION SYSTEM

Combustion experiments of dried wood chips and refuse derived fuel (RDF) under air and oxyfuel conditions have been performed in an extendedly modified 240 kW<sub>Th</sub> pilot-scale grate incineration facility with forward acting grate. To get insight into differences of the combustion processes between air and oxyfuel operation the concentrations of the main flue-gas species have been measured at the end of the combustion chamber and throughout the furnace. Additionally, the temperature has been measured inside the grate bars and the fuel bed as well as along the flue-gas pathway. It could be demonstrated that oxyfuel combustion of wood chips leads to stable CO<sub>2</sub> concentrations in the dry flue gas above 80 vol. %. During oxyfuel combustion of RDF similar trends have been observed; however, the combustion has shown significant fluctuations due to fuel-feeding issues. Profile measurements revealed a spatially extended reaction zone in the oxyfuel cases compared to the respective air combustion cases but with decreasing differences towards the end of the combustion zone. Wet flue-gas recycling has been applied to the experimental system which led to significantly higher H<sub>2</sub>O concentrations in the furnace during oxyfuel operation. Concentrations of CO, NO, SO<sub>2</sub>, and HCl in the flue gas have been increased during oxyfuel combustion. Especially during RDF oxyfuel combustion the concentration of HCl and SO<sub>2</sub> in the flue gas has been very high. In such a case it would be necessary to recycle the flue gas after appropriate cleaning steps. Also, considering the significantly lower flue-gas volume flow towards the atmosphere absolute emissions seem to be manageable.

Study of the Combustion Process for Two Refuse-Derived Fuel (RDF) Streams Using Statistical Methods and Heat Recovery Simulation

This study characterises materials that belong to the group of refuse-derived fuels (RDF). This group of materials regarded as an alternative fuel is derived from industrial, municipal solid and commercial wastes. The aim of this study is to evaluate the quality of waste composition, demonstrate statistically different values and the energy efficiency of the fuel derived from waste. Data on incinerated waste were collected from two different sources. The basic physical and chemical parameters of waste include density and water content. The lower heating value (LHV) of waste, chlorine concentration and ash content of two groups of incinerated waste were also evaluated and compared for a given period of time (one year, with monthly breakdown). Statistical analysis indicated the differences in the combustion of waste groups, visualized by box plots and other diagrams to show the distribution of the results. An analysis of exhaust gas parameters was carried out, both in terms of chemical composition and energy parameters. The RDF combustion process was presented through simulations for the adopted conditions of heat recovery. It was found that for each kilogram of RDF, about 3.85 kWh (13,860 kJ) of heat can be obtained. The combustion process was simulated using Aspen Plus software.

Multizone model of a refused derived fuel gasification: A thermodynamic Semi-empirical approach

Substitution of fossil fuels by sustainable energy sources has raised attention worldwide. Refuse derived fuel (RDF), which is the combustible fraction of Municipal solid waste (MSW), is used as an alternative fuel through combustion route. The gasification of RDF is gaining importance due to the operational issues of RDF combustion. The multizone RDF gasification model is developed to predict syngas composition in the present study. A stoichiometric approach is followed for modelling the pyrolysis and combustion zone. The reduction zone is modelled as a cylindrical fixed bed reactor with a uniform cross-sectional area. The developed set of differential equations is solved using MATLAB to predict the syngas properties. The novelty lies in the fact that the model can predict the output of each zone satisfactorily since the model assumptions are more realistic and cater to the heterogeneous nature of RDF. The impact of Equivalence ratio (ER), moisture content and reduction zone length on the performance of the gasifier are evaluated. The optimum values of lower heating value (LHV), gas yield, cold gas efficiency (CGE) and carbon conversion efficiency (CCE) for three different RDF at optimum ER is determined. Notably, 90% of the conversion is achieved within 60% length of reduction zone for all three types of RDF at all ERs. Predicting syngas properties can pave the way for the process integration of RDF gasification-based syngas in various industrial applications.

Snapshot review of refuse-derived fuels

Refuse-derived fuel (RDF) is generated by selected Municipal Solid Waste (MSW) fractions. Due to MSW composition changes by location, it is challenging to sell RDF as a product in the market. This article compiles the significant standards and rules governing RDF manufacture and usage. Additionally, it emphasizes the key actors that have already made a business of its commercialization and energy production through thermochemical processes. Combustion is the most often utilized thermochemical process, and this paper gathers information from several works on the combustion of RDF and RDF blends. Pyrolysis and gasification are also discussed, along with the primary benefits and drawbacks of RDF usage. Finally, the market's potential and significant constraints are examined. The primary constraint is the RDF price due to commercialization fees. However, RDF is aligned with the circular economy, sustainable development goals, and CO2 reductions by avoiding the extraction of new fossil fuels.

Single particle and packed bed combustion characteristics of high ash and high plastic content refuse derived fuel

This work reports fundamental combustion characteristics of high ash (∼ 18 %), high plastic (30–35 %) content refuse derived fuel (RDF) pellets produced currently in India. Single particle and packed bed studies of RDF were carried out to quantify RDF combustion times and RDF ash fusion behavior, respectively. Single particle studies concluded that RDF has glowing time to flaming time ratio of ∼ 3.5, which was similar to that of biomass and four times lower than that of coal. It was also observed that unlike biomass, upon heating, RDF particle showed a unique 5.6 to 10.3 % swelling behavior due to the melting of plastic. Packed bed experiments at different air mass flux on RDF pellets concluded that apart from air mass flux, ash content plays a decisive role on rate of flame propagation. The high plastic content of fuel increased ash fusion tendency inside the packed bed. Packed bed studies suggested maximum superficial velocity of ≤ 0.03 m s−1 to avoid clinker formation. Sieve analysis of RDF ash collected from packed bed studies reported soft ash at a lower air mass flux and bigger lumps of fused ash at higher air mass flux. Clinkers obtained at different air mass flux 0.02, 0.07, 0.13 kg m−2 s−1 were 1 %, 8 % and 11 % of the feed, respectively.

Waste-to-energy: Coal-like refuse derived fuel from hazardous waste and biomass mixture

This study aimed to develop Refuse Derived Fuel (RDF) with high Calorific Value (CV) from mixed hazardous wastes and biomass. The potential utilization of newly developed RDF in cement production as a fuel substitute for coal has been investigated. In this work, five types of mixed hazardous industrial wastes (rubber waste, mixed waste, paint sludge, palm oil sludge and wastewater treatment plant sludge) and three biomass types (sawdust, paddy husk and empty fruit bunch) have been used. The newly developed RDF developed in this study has a CV of approximately 18,652 kJ/kg, and its volatile matter, fixed carbon and ash content of 32 %, 40 % and 28 %, respectively. The study is revealed that substituting 5 ton/hour of RDF in the coal only emits about 301 mg/m3 of NOx, which is within the regulatory limits in Malaysia. Besides, the emission of heavy metals, including Zinc, Arsenic, Lead, Copper, Antimony, and Chromium, was also within the regulatory limits. RDF in cement manufacturing kilns is economically and environmentally attractive, as the combustion of RDF allows for a reduction of about 2.25 kg of CO2 per kg compared to coal. In terms of the efficiency of clinker and stack gas emission values, the substitution of 15 % of RDF to the coal at a feeding rate of 5 ton per hour in cement production did not cause any processing and quality issues in the existing cement production process. The result revealed that substituting 15 % of RDF with the coal in 5000 ton/day cement plant may reduce 112.8 USD/hour in operating cost. Additionally, 140 USD/hour of net saving could be achieved by saving 2.52 ton/hour of CO2 emitted from the cement production. Overall, the results concluded that RDF is a very promising resource recovery and waste treatment option for hazardous waste management.

Numerical investigation of the impact of coating layers on RDF combustion and clinker properties in rotary cement kilns

The formation of regions of solid coating, where agglomerated clinker material adheres to the refractory lining of the kiln wall, is very common during cement clinker production. While a thin coating layer protects the refractory lining, strong deposit formation can impair the material flow through the kiln. In this study, the impact of these coating layers on the clinker production process within a rotary kiln is investigated with CFD simulations. The fuel injected at the main burner is a mixture of pulverized coal and refuse derived fuel (RDF). Advanced models were developed to accurately describe the trajectories and thermal conversion of non-spherical RDF particles in the gas phase. These models are based on a detailed fuel analysis of major RDF fractions. A blocked-off region approach is used to consider different coating profiles within the simulation domain. The thermochemical processes in the clinker bed of the kiln are approximated with a one-dimensional model that calculates heat and mass exchange with the gas phase, the incorporation of fuel ashes into the bed and the chemical-mineralogical reactions of the clinker. The blocked-off region approach is also employed to account for the clinker bed geometry in the kiln, which greatly depends on the considered coating profile. Two cases, one with a thin and evenly distributed coating profile and one with a thick and locally concentrated coating, are simulated. The resulting impact on RDF conversion, gas phase properties and clinker phase formation are assessed and compared to a reference case without any coating. Results show that the insulation effect of a thin coating profile increases the gas phase temperature in the kiln and helps to reduce the free lime content of the final clinker product. In the case of heavy coating, a temperature shift towards the solid material inlet of the kiln occurs, which outweighs the beneficial insulation effect of the coating in the sintering zone and leads to lower local gas phase temperatures. In combination with reduced clinker residence times, this results in a slight increase of the free lime content in the clinker.

Life Cycle Assessment of Refuse Derived Fuel (RDF) for Municipal Solid Waste (MSW) Management: Case Study Area Around Cement Industry, Cirebon, Indonesia

Life Cycle Assessment (LCA) is a useful tool to evaluate the environmental impact of Municipal Solid Waste (MSW) processing. Here, a BUMDES (village owned enterprise) converted MSW to Refuse Derived Fuel (RDF) in the area around a cement plant in Cirebon, Indonesia. The RDF that is produced is used as a partial substitutiton fuels for the kiln in the cement industry. The purpose of present study was to evaluate the environmental impacts of RDF production through an attributional LCA study. The results were compared with the current practice of MSW treatment system. The waste management system that will be compared includes RDF and direct combustion. LCA simulation was conducted in the OpenLCA software, which is equipped with ecoinvent database as well as primary data from the field. The company treated about 2, 259.96 kg of waste / day. The results showed that the production rate of RDF is about 966 kg / day. The analysis shows that the conversion of combustible municipal solid waste into RDF is more environmentally friendly than direct combustion with environmental impacts as follows: GWP 8.40E-01 kg CO2 eq., Acidification 4.36E-04 kg SO2 eq., Eutrophication 7.18E-04 kg PO4 eq., ODP 3.59E-09 kg CFC-11 eq., And Human toxicity 2.27E-01 kg 1.4 dichlorobenzene eq. The use of RDF as a substitute fuel for the cement industry is economically advantageous if: there are no restrictions on processed waste, the RDF product sales to the cement industry is ensured, and the RDF product price should be economically viable. The initial investment costs and high operating as well as the maintenance costs could be a challenging issue when dealing with MSW processing to RDF.

Effect of microwave chlorine depleted pyrolyzate on the combustion characteristics of refuse derived fuel derived from package waste

Thermogravimetric-Fourier Transform Infrared Spectroscopy was conducted to evaluate the combustion characteristics of refuse derived fuel (RDF) adding of microwave chlorine depleted pyrolyzate in the mass proportion of 5–15%. It studied the catalyze effect of chlorine depleted pyrolyzate on RDF combustion performance. The combustion process of RDF could be divided into four stages. The temperature range of the most significant combustion stage of 10-RDF was much more extensive than another three ones. According to the FTIR analysis, the addition of chlorine depleted pyrolyzate might promote the combustion of CH4 and carbonyls to CO2 and H2O earlier. Based on the distributed activation energy model (DAEM), the E value of RDF with chlorine depleted pyrolyzate added was much lower than that with no chlorine depleted pyrolyzate added. The chlorine depleted pyrolyzate enhanced the combustion performance of RDF with the lower ignition, lower burnout temperature, better combustion ability, better flammability and more outstanding combustion performance. The best combustion characteristic was obtained when the dosage of chlorine depleted pyrolyzate was 10%.

RDF pyrolysis by TG-FTIR and Py-GC/MS and combustion in a double furnaces reactor

With the increasing depletion of fossil energy, the refuse-derived fuel (RDF) as an unavoidable by-product of human activities has been used as an alternative fuel in the precalciner cement kilns. Since the RDF combustion also brings the problems of NOx pollution, it is quite important to find ways to lower the NOx emission during RDF combustion in the precalciner. The pyrolysis characteristics and products of RDF were studied by TG-FTIR and Py-GC/MS. From TG-FITR and Py-GC/MS tests, various carboxylic acids and alkenes formed with NOx released at the RDF pyrolysis process at 200–550 °C. By simulating the temperature (700 °C, 800 °C and 900 °C) and O2 (12%, 14%, 16%, 18% and 21%) environment of the precalciner using a double furnaces reactor, the combustion processes and NOx formation characteristics of RDF combustion were studied. The results showed that the volatile-N was the dominant reactant source of fuel NOx during RDF combustion. The fuel-N conversion and NOx emission yield showed a continuous decreasing trend with temperature increasing from 700 to 900 °C. The fuel-N conversion and NOx emission yield showed a slight increasing trend with the oxygen concentration increase, and the optimum oxygen concentration for RDF combustion was 14%. In this study, the optimum temperature was 900 °C and oxygen concentration was 14% for de-NOx in the precalciner.

Life cycle greenhouse gas evaluation of organic rankine cycle using refuse-derived fuel from municipal solid waste

In Thailand, the rise in population and economic growth have caused waste generation to increase rapidly, leading to increases in greenhouse gases (GHGs) being released to the atmosphere from waste landfills. Application of waste-to-energy technology to produce electricity can reduce waste accumulation in landfills in addition to lessening the GHG emissions. This study aimed to evaluate life cycle GHG emissions from application of organic Rankine cycle (ORC) as waste-to-energy technology using refuse-derived fuel (RDF), which is produced from municipal solid waste, according to the life cycle assessment approach. The functional unit is defined as 1 kWh. The results indicate that the GHG emissions of 1 kWh of power generated from a RDF hybrid with an ORC power generation system are mostly contributed from RDF combustion in the operation stage, which accounts for 77% of the total. The RDF hybrid ORC shows fewer GHG emissions than the existing combustion-based power generation in Thailand, except for natural gas with the combined-cycle technology. The RDF hybrid ORC power generation can reduce 51.47% of GHG emissions when compared with an open dump, and 34.31% when compared with a landfill. The RDF hybrid ORC was also demonstrated as an environmentally friendly system that can be considered as a source of power generation in power planning in the future.

Comparison of fuel value and combustion characteristics of two different RDF samples

Generation of Municipal Solid Waste (MSW) tends to increase with the growing population and economic development of the society; therefore, establishing environmentally sustainable waste management strategies is crucial. In this sense, waste to energy strategies have come into prominence since they increase the resource efficiency and replace the fossil fuels with renewable energy sources by enabling material and energy recovery instead of landfill disposal of the wastes. Refuse Derived Fuel (RDF), which is an alternative fuel produced from energy-rich Municipal Solid Waste (MSW) materials diverted from landfills, is one of the waste to energy strategies gaining more and more attention. This study aims to investigate the thermal characteristics and co-combustion efficiency of two RDF samples in Turkey. Proximate, ultimate and thermogravimetric analyses (TGA) were conducted on these samples. Furthermore, elemental compositions of ash from RDF samples were determined by X-Ray Fluorescence (XRF) analysis. The RDF samples were combusted alone and co-combusted in mixtures with coal and petroleum coke in a lab scale reactor at certain percentages on energy basis (3%, 5%, 10%, 20% and 30%) where co-combustion processes and efficiencies were investigated. It was found that the calorific values of RDF samples on dry basis were close to that of coal and a little lower compared to petroleum coke used in this study. Furthermore, the analysis indicated that when RDF in the mixture was higher than 10%, the CO concentration in the flue gas increased and so the combustion efficiency decreased; furthermore, the combustion characteristics changed from char combustion to volatile combustion. However, RDF addition to the fuel mixtures decreased the SO2 emission and did not change the NOx profiles. Also, XRF analysis showed that the slagging and fouling potential of RDF combustion was a function of RDF portion in fuel blend. When the RDF was combusted alone, the slagging and fouling indices of its ash were found to be higher than the limit values producing slagging and fouling.

Thermogravimetric analysis on the combustion characteristics of refuse-derived fuel under an oxygen-enriched atmosphere

The combustion processes of refuse-derived fuel (RDF) under an oxygen-enriched atmosphere are analyzed by thermogravimetry and the combustion characteristics of RDF are studied. The factors influential to the combustion characteristics of RDF include the plastic content, heating rate and oxygen concentration. Investigation of RDF combustion characteristics can provide an important basis for the design and selection of combustion equipment. Meanwhile, the combustion activation energy and frequency factor are obtained by the Doyle method, and then the combustion model of RDF under an oxygen-enriched atmosphere is established. This study provides an essential basis for the spread of and oxygen-enriched combustion of RDF technology.

Fuzzy Analytical Hierarchy Process Disposal Method Selection for an Industrial State; Case Study Charmshahr

Industrial states generate significant amounts of wastes. Industrial states’ managers are worried about how to select a proper disposal method for their solid waste management. Gathering over 200 different factories in Charmshahr state is leading to produce over 77 tons waste per day. In this study, Fuzzy Analytical Hierarchy Process is used to choose the best disposal method for an industrial state named Charmshahr with regard to the existence uncertainty and lack of knowledge. This state contains more than 200 factories most of which are leather and tannery industries. Four alternatives, namely landfilling, recycling, Refuse Derived Fuel combustion and conventional incineration are considered as the disposal methods. Also the linguistic comparisons which are compatible with fuzzy sets are used for more real and accurate decision making. The pair-wise comparisons are made based on individual experts’ judgments on eight criteria namely costs, technical reliability, feasibility, waste consistency, environmental impacts, social viewpoints, available knowledge and maintenance. Environmental impacts have the most effects on the estimated weights, whereas social issues have the least. Finally, with regard to the results, especially economical issues, feasibility and water and soil pollutions, landfilling is found as the most proper disposal method for Charmshahr industrial state.

Combustion behavior and pollutant emission characteristics of RDF (refuse derived fuel) and sawdust in a vortexing fluidized bed combustor

This paper presents the results obtained from RDF and sawdust combustion in a pilot scale vortexing fluidized bed combustor (VFBC). Flue gas recirculation (FGR) combustion mode was employed. The effects of operating parameters such as bed temperature, excess oxygen ratio, and in-bed stoichiometric oxygen ratio on the combustion behavior and pollutant emission characteristics were investigated. The experimental results show the different combustion characteristics with different fuels in the VFBC. For sawdust combustion, CO emission decreases with bed temperature, excess oxygen ratio, and in-bed stoichiometric oxygen ratio. The NOx emission shows an inverse trend. Combustion using sawdust as the fuel has difficulty meeting the CO emission regulation requirement. The CO and NOx emissions of RDF combustion show a similar trend as that of sawdust; however RDF combustion can significantly decrease the CO emission due to its distinct pellet structure and burning pattern.

Determination of fossil fraction of Refuse Derived Fuel by the Selective Dissolution Method in Calorific value basis: Development of simplified method

Determination of net CO2 emissions from combustion of Refuse Derived Fuel (RDF) is not straight forward due to the heterogeneous nature of the fuel. The fossil fraction of the fuel is an essential parameter for the determination of net CO2 emissions. In the present study, the fossil fraction of RDF is determined by means of the Selective Dissolution Method (SDM) in calorific value basis. Seven artificially made RDF mixtures were tested using this method. The mixtures were prepared by mixing different proportions of plastic, paper and wood. It was found that the experimentally determined fossil fractions were very close to the theoretical values, which could be calculated based on the constituents of the artificial RDF mixtures. This indicates a high accuracy of SDM. However, SDM is a time-consuming method. Based on the artificially made RDF mixtures, a functional relationship between calorific value and fossil fraction in calorific value basis was found and plotted graphically. This means that in cases where the nature of the fossil and biogenic RDF constituents is known, determination of the calorific value, ash content and moisture content of the fuel is sufficient for determination of the fossil fraction in calorific value basis. Since these parameters can be relatively quickly determined at least within one day, and are often analyzed anyway as part of the general fuel characterization, this simplified method can save a lot of time and resources compared to SDM, which takes three days to give a test result. Hence, the simplified method can be an attractive alternative to SDM when net CO2 emissions from RDF combustion are to be determined. When performing the SDM analysis, attention should be given for the intermediate calculations since some of the ash forming matter penetrates into the filter paper used in the SDM procedure.

In-Situ Monitoring of Toxic Heavy Metals from RDF Combustion by Two-Dimensional Atomic Absorption Spectrometry

The method to visualize two-dimensional (2D) distributions of heavy metals in refuse-derived fuel (RDF) combustion flame by using 2D atomic absorption spectrometry (2D-AAS) was studied. In-situ monitoring of the heavy metal vaporization was performed to gather useful information on the reduction of their emissions. The RDF sample was burned on a burner with an O2/N2 gas mixture being supplied from the bottom. Easily vaporized metals such as mercury (Hg) and cadmium (Cd) present in the RDF flame were measured by 2D-AAS. In order to measure the atomic absorption of lead (Pb), a sub-burner supplying O2 was placed in the RDF flame. O2 reacts with unburned gases in the RDF flame, increasing the flame temperature locally. Consequently, atomic absorption of Pb became measurable, and its 2D profiles were obtained by mapping. In addition, quantitative analyses of Hg and Cd contained in the RDF were made using the standard addition method without any pretreatments.