Reduced bed temperature in a commercial waste to energy boiler — Impact on ash and deposit formation

Pettersson, Anita; Niklasson, Fredrik; Moradian, Farzad

doi:10.1016/j.fuproc.2011.09.001

Cited by 19 publications

(32 citation statements)

References 11 publications

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“…For S and Cl, this is more noteworthy given that S and Cl concentrations in the fuel in both the Ref and AW cases were fairly similar (Figure 3). This may be linked to the lower bed temperature because the results are close to those from the RBT case, in which the lower bed temperature led to higher capture of S and Cl in the bed material coating [8]. Ca and P, mainly introduced as bone tissue with the AW, seem to be enriched in the bed ashes.…”

Section: Chemical Analysis Of Ashessupporting

confidence: 53%

“…These boilers produce superheated steam of 405 °C and 49 bar, used for power and heat production. The boilers are designed for a bed temperature of 870 °C, but due to decreased bed agglomeration and lower deposition growth rate in the RBT project [8], the goal is a bed temperature of 750 °C. …”

Section: The Boilermentioning

confidence: 99%

“…The ordinary composition of Swedish sands, which contain feldspars, make it difficult to distinguish, analytically, between the sands and ashes. Quartz (SiO 2 ), albite (NaAlSi 3 O 8 ), microklin (KAlSi 3 O 8 ) and klinoklor ((Mg,Al) 6 (Si,Al) 4 O 10 (OH) 8 ) are compounds found in the fresh sand. Several of these compounds were also found in the ash, for example, quartz, albite and microklin in the boiler ash.…”

Section: Xrdmentioning

confidence: 99%

“…The positive effects of AW co-combustion on the bed agglomeration are shown in Figure 12a,b, in which visual inspection of the bed ashes for both cases shows considerably less amount of agglomerated particles in the AW case than do those from the Ref case. This difference could be explained by the change in temperature, the changed chemistry or both [8]. The results of the lab-scale bed agglomeration test are presented in Table 5.…”

Section: Bed and Agglomeration Temperaturementioning

confidence: 99%

“…Improved boiler operation has been investigated by either modifying the boiler function or changing the fuel mix. For example, a previous full-scale project, the Reduced-Bed Temperature (RBT) project [8], reduced the bed temperature by recirculating flue gas and spraying water on the fuel to modify the boiler function. The outcome was positive in terms of deposit formation rate, fly ash flow rate, reduced risk of bed agglomeration and some capture of chlorine in the bed [8].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Co-Combustion of Animal Waste in a Commercial Waste-to-Energy BFB Boiler

Moradian

Pettersson

Svärd³

et al. 2013

Energies

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Co-combustion of animal waste, in waste-to-energy boilers, is considered a method to produce both heat and power and to dispose of possibly infected animal wastes. This research conducted full-scale combustion tests to identify the impact of changed fuel composition on a fluidized-bed boiler. The impact was characterized by analyzing the deposit formation rate, deposit composition, ash composition, and emissions. Two combustion tests, denoted the reference case and animal waste case, were performed based on different fuel mixes. In the reference case, a normal solid waste fuel mix was combusted in the boiler, containing sorted industry and household waste. In the animal waste case, 20 wt% animal waste was added to the reference fuel mix. The collected samples, comprising sampling probe deposits, fuel mixes, bed ash, return sand, boiler ash, cyclone ash and filter ash, were analyzed using chemical fractionation, SEM-EDX and XRD. The results indicate decreased deposit formation due to animal waste co-combustion. SEM-EDX and chemical fractionation identified higher concentrations of P, Ca, S, and Cl in the bed materials in the animal waste case. Moreover, the risk of bed agglomeration was lower in the animal waste case and also a decreased rate of NO x and SO 2 emissions were observed.

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Section: Chemical Analysis Of Ashessupporting

confidence: 53%

Section: The Boilermentioning

confidence: 99%

Section: Xrdmentioning

confidence: 99%

Section: Bed and Agglomeration Temperaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Co-Combustion of Animal Waste in a Commercial Waste-to-Energy BFB Boiler

Moradian

Pettersson

Svärd³

et al. 2013

Energies

Self Cite

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Predicting Melt Formation and Agglomeration in Fluidized Bed Combustors by Equilibrium Calculations

Billen

Caneghem

Vandecasteele

2013

Waste Biomass Valor

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Thermal valorization of biomass or waste in a fluidized bed combustor may result in agglomeration of the bed material, coated with ash, potentially causing defluidization. In this paper, the causes of agglomeration for various fuels are critically reviewed, based on thermodynamic grounds. It is shown that even for phosphorus rich biomass types, in most cases the largest melt phase consists of alkali silicates: Ca phosphates are formed instead of Ca silicates, leading to lower melting points in the CaO-K2O-SiO2 system. Although thermodynamic optimization of the four main ash forming elements (K, Ca, Si and P) only provides an estimate of the amount of melt phase, it is shown that for various fuels the agglomeration behavior can be explained consistent with experimental findings from literature. As a consequence, for most biomass and waste types a similar thermodynamic estimation can be made to predict agglomeration problems and incorporate countermeasures in the design and operation of the fluidized bed combustor.

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In-situ sampling investigation of deposition and corrosion of convective heating surfaces in a grate type municipal solid waste incineration plant: a case study

Liu

Qian

Liu

et al. 2021

Waste Dispos. Sustain. Energy

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Metal corrosion and ash deposition are two common issues in municipal solid waste incineration (MSWI) plants. An insitu sampling investigation was conducted in an MSWI plant in Jiangsu, China. The deposit samples were collected from 6 convective heating surfaces including the reheaters, superheaters, and economizer. The corrosion samples were obtained from a ruptured tube cut from the tertiary superheater. The element composition, crystal phases, and morphology of deposit and corrosion samples were characterized and analyzed. The results show that S contents of these deposits are 32-45 wt%, considerable Cl (10.63 wt%) was only detected in the deposits of the tertiary superheater. The composition of the deposits varies with the location because the flue gas temperature determines the thermodynamic trend of the sulfation reactions of different chlorides and the SO 2 equilibrium partial pressure required in these reactions. Ca sulfates mainly exist in deposits at high temperatures (above approximately 500 °C). Whereas alkali metal sulfates are the main component of deposits at low temperatures (below approximately 500 °C). A multi-layer structure is exhibited on the cross-section of the corrosion samples. The discovery of Cl in the interface between the matrix and the oxide layer confirms that Cl can penetrate the outer oxide film. Besides, polysulfate components were observed inside the metal oxide layers, which indicates that a melt has occurred there. This study has provided a better understanding of ash deposition and corrosion phenomena in MSWI systems and more emphasis should be placed on the research of ash deposition and corrosion mechanisms.

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Reduced bed temperature in a commercial waste to energy boiler — Impact on ash and deposit formation

Cited by 19 publications

References 11 publications

Co-Combustion of Animal Waste in a Commercial Waste-to-Energy BFB Boiler

Co-Combustion of Animal Waste in a Commercial Waste-to-Energy BFB Boiler

Predicting Melt Formation and Agglomeration in Fluidized Bed Combustors by Equilibrium Calculations

In-situ sampling investigation of deposition and corrosion of convective heating surfaces in a grate type municipal solid waste incineration plant: a case study

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