Analysis and prediction of slag-induced corrosion of chromium oxide-free refractory materials during fusion of coal and biomass ash under simulated gasification conditions

Reinmöller, Markus; Klinger, Mathias; Thieme, Enrico; Meyer, Bernd

doi:10.1016/j.fuproc.2016.04.022

Cited by 51 publications

(14 citation statements)

References 25 publications

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“…Furthermore, the refractory wall of the gasifier was often corroded in current commercial gasifiers. Several semiempirical models were developed to calculate the corrosion rate of refractory bricks. − The corrosion process of refractory materials usually included a series of complex physical interactions and chemical reactions, which are related to the slag properties, refractory materials properties, reaction, gas component, penetration and diffusion, abrasion, pressure, and refractory wall surface temperature. − Thus, it is difficult to find a unified model to describe the corrosion process, and only a simplified model can be established for a certain refractory material to analyze the main corrosion factors. However, the literature studies on refractory wall corrosion mainly focused on high chromium refractory bricks in a refractory brick lining gasifier.…”

Section: Introductionmentioning

confidence: 99%

Modeling Study of the Slag Behaviors and SiC Refractory Wall Corrosion on the Top Cone of a Membrane Wall Entrained-Flow Gasifier

2020

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Slag behaviors on the top cone are significant characteristics that relate to the refractory wall corrosion and safe operation in a membrane wall gasifier. The slag flow and heat transfer model was established to predict the slag behaviors on the top cone of a gasifier. The results showed that the closer to the top outlet of the gasification chamber, the thinner the slag thickness, the higher the slag layer heat flux density and refractory wall surface temperature. The mean slag thickness of the top cone was thinner and the mean heat flux density of the top cone was higher than that of the bottom cone, thus the protection of the upper refractory wall was weakened. Especially, the heat transfer rate of the overall top cone significantly decreased when the cone angle increased. Moreover, the refractory wall corrosion model was built based on the active oxidation behavior. The results showed that the refractory wall surface temperature and linear corrosion rate significantly increased, while the gas temperature increased.

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Section: Introductionmentioning

confidence: 99%

Modeling Study of the Slag Behaviors and SiC Refractory Wall Corrosion on the Top Cone of a Membrane Wall Entrained-Flow Gasifier

2020

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“…2 Therefore, the fluidity and corrosivity of slag are the main key factors for the stability and long-time operation of the entrained-flow gasifier. 3 A coal−water slurry gasifier possessing a refractory brick wall as the lining is widely used due to its engineering stability. 4 Currently, high chromia refractory materials are used as the fire-resistant refractories in slurry gasifiers.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the typical slag viscosity for gasifier operation is in the range from 5 to 25 Pa·s, and this directly decides the operation temperature of the gasifier . Therefore, the fluidity and corrosivity of slag are the main key factors for the stability and long-time operation of the entrained-flow gasifier …”

Section: Introductionmentioning

confidence: 99%

Dissolution of Cr₂O₃ into Coal Slag and Its Impact on Slag Flow Properties

et al. 2020

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In an entrained-flow coal gasifier, gasification slag derived from the melting of mineral matter in coal flows along the refractory wall and is tapped out. The refractory of spallation and dissolution enters into coal slag and can affect the slag flow properties, which are crucial for the entrained-flow gasifier's smooth operation. Cr 2 O 3 is one of the most common compositions of refractory materials and is selected to research the effect of refractory on the flow properties of slag. In this work, the dissolution of Cr 2 O 3 into coal slag is calculated by FactSage software, and its impact on ash fusion temperatures and slag viscosity are investigated. The Cr 2 O 3 concentration of coal slag increases from 0.5 to 4 wt % as the operation temperature rises (1300−1600 °C). Cr 2 O 3 reacts with FeO to form the high-melting point mineral donathite during the ash melting process, and the retention of FeO reduces the formation of low-melting point clinopyroxene, leading to the increase of ash fusion temperatures with the Cr 2 O 3 content. In addition, the slag viscosity increases with the Cr 2 O 3 content because of the increasing polymerization degree of the slag structure. Crystalline donathite formed by Cr 2 O 3 is precipitated first during the cooling process, and the precipitated donathite acts as the heterogeneous nucleus, promoting the precipitation of troilite and anorthite and thus increasing the critical viscosity temperature. This suggests that the high-chromia refractory material corrosion can cause the fluctuation of slag flowability and even lead to slag blockage. Therefore, the gasifier cannot be operated beyond the upper limit of operation temperature (1600 °C) for a long time to avoid the severe dissolution of refractory materials.

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“…Many researchers used scanning electron microscopy (SEM), energy dispersive X-ray detection (EDX), and X-ray diffractometry (XRD) to study the erosion of different kind of refractory materials by alkali metal carbonates [21,22,23,24,25,26,27,28]. The corrosion mechanism of refractory materials by sodium salts is studied from the viewpoint of slag and sedimentt; the anti-sodium corrosion performance of different types of refractory materials is compared, and the best material is selected.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Study of the Corrosion of Refractories by Sodium Carbonate

et al. 2018

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The corrosion of refractories by sodium salts in waste liquid at high temperature has become a serious problem. This paper focuses on the thermodynamic characterization of sodium carbonate (Na2CO3) corrosion of six refractories by FactSage modelling in combination with X-ray diffraction (XRD). Three of the refractories are oxides (Fe2O3, Al2O3, and Cr2O3), and the other three are synthetics spinels (magnesium chromium, MgO·Cr2O3; magnesioferrite, MgO·Fe2O3; and, magnesium aluminium, MgO·Al2O3). First, thermodynamic simulations were carried out with the FactSage thermodynamics model using the reaction package to predict the direction of the Na2CO3 corrosion reaction in terms of the Gibbs free energy. Then, the reactions between the six refractories and Na2CO3 were conducted through a series of refractories/Na2CO3 reaction tests. The XRD analytical method was used to describe and understand the chemistry and interpret mineral matter transformation. The products of the tests were also determined by X-ray diffraction and the experimental observations were compared with the results of the thermodynamic simulations. Furthermore, the strength of sodium corrosion of the refractory materials was comprehensively discussed. The results show that MgO·Al2O3 has the best thermal stability and it is hard to corrode by Na2CO3, while the chrome-containing refractory reacts easily with Na2CO3 with a considerably high amount of corrosion product at a temperature of 600 °C. These experimental results are in agreement with the thermodynamic calculations.

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Analysis and prediction of slag-induced corrosion of chromium oxide-free refractory materials during fusion of coal and biomass ash under simulated gasification conditions

Cited by 51 publications

References 25 publications

Modeling Study of the Slag Behaviors and SiC Refractory Wall Corrosion on the Top Cone of a Membrane Wall Entrained-Flow Gasifier

Modeling Study of the Slag Behaviors and SiC Refractory Wall Corrosion on the Top Cone of a Membrane Wall Entrained-Flow Gasifier

Dissolution of Cr₂O₃ into Coal Slag and Its Impact on Slag Flow Properties

Thermodynamic Study of the Corrosion of Refractories by Sodium Carbonate

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Analysis and prediction of slag-induced corrosion of chromium oxide-free refractory materials during fusion of coal and biomass ash under simulated gasification conditions

Cited by 51 publications

References 25 publications

Modeling Study of the Slag Behaviors and SiC Refractory Wall Corrosion on the Top Cone of a Membrane Wall Entrained-Flow Gasifier

Modeling Study of the Slag Behaviors and SiC Refractory Wall Corrosion on the Top Cone of a Membrane Wall Entrained-Flow Gasifier

Dissolution of Cr2O3 into Coal Slag and Its Impact on Slag Flow Properties

Thermodynamic Study of the Corrosion of Refractories by Sodium Carbonate

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Dissolution of Cr₂O₃ into Coal Slag and Its Impact on Slag Flow Properties