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Hermann Hofbauer - One of the best experts on this subject based on the ideXlab platform.
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Influence of bed materials on the performance of the Nong Bua dual fluidized bed gasification power plant in Thailand
Biomass Conversion and Biorefinery, 2020Co-Authors: Vilailuck Siriwongrungson, Janjira Hongrapipat, Jullapong Thaveesri, Michael Messner, Matthias Kuba, Shusheng Pang, Reinhard Rauch, Hermann HofbauerAbstract:Bed materials and their catalytic activity are two main parameters that affect the performance of the dual fluidized bed (DFB) gasification system in terms of product gas composition and tar levels. Two sources of bed materials were used for the operation of a commercial DFB gasification system in Thailand, using woodchips as a Biomass feedstock. One source of the bed materials was the calcined olivine which had been used in the Gussing Plant, Austria, and the other activated bed material was a mixture of fresh Chinese olivine and used Austrian olivine with additives of Biomass Ash, calcium hydroxide and dolomite. These bed materials were collected and analysed for morphological and chemical composition using a scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray fluorescence spectroscopy (XRF). The product gas was cleaned in a scrubber to remove tars, from which the samples were collected for gravimetric tar analysis. Its composition data was automatically recorded at the operation site before it entered the gas engine. From the SEM, EDS and XRF analyses, calcium-rich layers around the bed materials were observed on the activated bed material. The inner layers of bed materials collected were homogeneous. Biomass Ash, which was generally added to the bed materials, had significant calcium and potassium content. These calcium-rich layers of the bed materials, from the calcium hydroxide, Biomass Ash and dolomite, influenced system performance, which was determined by observing lower tar concentration and higher hydrogen concentration in the product gas.
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apparent kinetics of the water gas shift reaction in Biomass gasification using Ash layered olivine as catalyst
Chemical Engineering Journal, 2018Co-Authors: J Kryca, Juraj Priscak, Joanna łojewska, Matthias Kuba, Hermann HofbauerAbstract:Abstract Substitution of fossil fuels for production of electricity, heat, fuels for transportation and chemicals can be realized using Biomass steam gasification in a dual fluidized bed (DFB). Interaction between Biomass Ash and bed material in a fluidized bed leads to transformation of the bed particle due to enrichment of components from the Biomass Ash resulting in the development of Ash layers on the bed particle surface. These Ash-rich particle layers enhance the catalytic activity of the bed material regarding the water-gas-shift reaction and the reduction of tars. The water-gas-shift reaction at conditions typical for dual fluidized bed Biomass gasification at a temperature of 870 °C was investigated. Diffusion and heat transfer limitations were minimized using a lab-scale experimental set-up consisting of a gas mixing section and a quartz glass reactor in which the catalyst is investigated. The following new rate expression for the water-gas-shift reaction in dual fluidized bed gasification of Biomass was empirically developed, which takes Ash layer formation into account: r Olivine _ Ash - layer = 8 , 9 · 10 - 6 exp - 95000 RT p CO 1 , 96 p H 2 O 1 , 81 p CO 2 - 0 , 75 p H 2 - 1 , 69
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the mechanism of bed material coating in dual fluidized bed Biomass steam gasification plants and its impact on plant optimization
Powder Technology, 2013Co-Authors: Friedrich Kirnbauer, Hermann HofbauerAbstract:Abstract The bed material and especially its catalytic activity plays an important role in Biomass steam gasification in dual fluidized bed gasifiers. The bed material is modified by interaction with Biomass Ash during operation of the gasification plant forming layers at the particles which are induced by the Biomass Ash. Optimization of dual fluidized Biomass steam gasification will have significant influence on the process variables such as temperatures, inorganic composition and product gas composition. The influence of these changes on layer formation is still unknown. This paper summarizes results of investigations about bed material characteristics taken from the industrial-scale Biomass steam gasification plant in Gussing where woody Biomass is used as fuel. Analyses of the surface and the crystal structures of the bed material particles treated in gasification and combustion atmospheres were carried out. The thermal behavior of used olivine and fresh olivine in different atmospheres was analyzed. A suggestion for the mechanism of formation of the layers is presented and the influence of possible optimization measures is discussed. A change in the elemental composition of the surface was not detectable but a slight change in the crystal structure. Thermal investigations show a weak endothermic weight loss with used olivine in a CO 2 -rich atmosphere which could not be determined with fresh olivine. The formation of layers at the olivine particles is considered to be caused by the intensive contact with burning char particles in the combustion reactor.
Guangsuo Yu - One of the best experts on this subject based on the ideXlab platform.
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understanding the effect of different Biomass Ash additions on pyrolysis product distribution char physicochemical characteristics and char gasification reactivity of bituminous coal
Energy & Fuels, 2019Co-Authors: Lu Ding, Guangsuo Yu, Yan Gong, Junqin YuAbstract:In this study, two typical Biomass Ash additives, rice straw Ash (RSA), high K and high Si and cotton stalk Ash (CSA, high K–Ca–Na and low Si), were adopted as natural and effective catalysts to systematically investigate the influence of Biomass Ash type on pyrolysis product distribution, char physicochemical characteristics (i.e., chemical forms and concentrations of alkaline and alkaline earth metals (AAEMs), pore structure, and carbon structure), and char gasification reactivity of bituminous coal. The results of pyrolysis product distribution show that RSA additive resulted in an increase of tar yield and decrease of char yield during coal pyrolysis, whereas CSA additive led to a decrease of tar yield and increase of gas yield in coal pyrolysis. The RSA additive had little impact on the gaseous product yields of coal pyrolysis, but the CSA additive obviously enhanced H2, CO, and CO2 yields of coal pyrolysis and slightly inhibited the CH4 yield of coal pyrolysis. The results of char physicochemical pr...
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influence of Biomass Ash additive on reactivity characteristics and structure evolution of coal char co2 gasification
Energy & Fuels, 2018Co-Authors: Yan Gong, Guangsuo Yu, Lu Ding, Junqin YuAbstract:In this study, the influence of Biomass Ash (rice straw Ash, RSA) additive on char gasification reactivity of different rank coals (Shenfu bituminous coal and Zunyi anthracite) was investigated using thermogravimetric analysis. Moreover, the structure characteristics (i.e., the chemical forms and concentrations of AAEM species and the order degree of carbon structure) of gasified semichars were quantitatively studied to evaluate the effect of RSA additive on coal char structure evolution during gasification. Specific reactivity index was proposed as a quantitative index and showed that RSA additive facilitated coal char gasification, especially at lower gasification temperature and for high-rank coal char. In addition, the results from the active AAEM concentrations and the Raman band area ratios of gasified semichars indicate that the RSA additive was conducive to the increase of active AAEM concentrations in coal char and the decrease of the degree of graphitization of coal char carbon structure during ...
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the physicochemical properties of different Biomass Ashes at different Ashing temperature
Renewable Energy, 2011Co-Authors: Ruirui Xiao, Xueli Chen, Fuchen Wang, Guangsuo YuAbstract:There are no specific standards for Biomass Ash analysis in China, so the standards for coal Ash analysis are usually used to determine the property of Biomass Ash. Three kinds of Biomass including rice straw, pine sawdust and Chinese Parasol Tree leaf burned at 815 °C, 600 °C and 500 °C respectively corresponding to the temperature required in the standard of GB and ASTM. The Ash content and composition were analyzed. Based on the Ash composition results, the volatilization of alkali oxides in Biomass Ash and slagging/fouling problems related to Biomass thermochemical conversion were investigated. The alkali metals were relatively more volatile with the increasing of Ashing temperature. The crystalline phase composition and surface morphology characteristics of the Ash particles were investigated by XRD and SEM analysis. The increasing Ashing temperature resulted in the decreasing of the diffraction intensities of metal salts and the increasing of the diffraction intensities of silicon compound. Ash fusion temperatures were measured by 5E-AFII Ash Fusion Analyzer. The results indicated that the Ash content, composition, crystalline phases composition, surface morphology and Ash fusibility were all closely related to Ashing temperatures. The analysis at 600 °C Ashing temperature was regarded as the optimal for an exact determination of Ash properties.
Wei Qian - One of the best experts on this subject based on the ideXlab platform.
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effects of Biomass Ash bone meal and alkaline slag applied alone and combined on soil acidity and wheat growth
Journal of Soils and Sediments, 2017Co-Authors: Jiuyu Li, Ni Ni, Khalid Mehmood, Renkou Xu, Wei QianAbstract:Purpose The purpose of this study is to examine the effects of combined application of Biomass Ash (BA), bone meal (BM), and alkaline slag (AS) on soil acidity, nutrient contents, uptake of the nutrients by wheat, and wheat growth.
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effects of Biomass Ash bone meal and alkaline slag applied alone and combined on soil acidity and wheat growth
Journal of Soils and Sediments, 2017Co-Authors: Renyong Shi, Khalid Mehmood, Wei QianAbstract:The purpose of this study is to examine the effects of combined application of Biomass Ash (BA), bone meal (BM), and alkaline slag (AS) on soil acidity, nutrient contents, uptake of the nutrients by wheat, and wheat growth. A pot experiment with an Ultisol collected from Anhui province, China, was conducted to compare the effects of BA, BM, and AS applied alone and combined on soil acidity; soil nutrient contents; uptake of N, P, K, Ca, and Mg by wheat, and wheat growth. Application of BA, BM, and AS alone and combined increased soil pH and decreased soil exchangeable Al3+. BA + BM + AS showed the greatest ameliorating effect on soil acidity, and soil pH of the treatment increased by 1.24 units compared with control. Application of BA + BM + AS reduced soil exchangeable Al3+ and increased soil exchangeable calcium and magnesium to a greater extent than BA + BM and single application of the amendments. The BM-containing amendments substantially increased soil available phosphorous by 66–93% compared with control. Application of the amendments alone and combined enhanced the uptake of N, P, K, Ca, and Mg by wheat and thus promoted wheat growth and increased yield of wheat grains. Application of BA + BM + AS and BA + BM showed greater effects on nutrient uptake and wheat growth than single application of the amendments. Wheat straw weights of the two treatments were 11.1 and 10.1 times greater than that of control. The data were 2.7, 4.8, and 5.6 times for the treatments of BA, AS, and BM. The contents of Cd, Cr, Zn, and Cu in wheat grains were lower than standard limits, except for the single BA treatment. BA + BM + AS is the best choice for amelioration of acid soils and promotion of crop production.
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ameliorating effects of individual and combined application of Biomass Ash bone meal and alkaline slag on acid soils
Soil & Tillage Research, 2016Co-Authors: Jiuyu Li, Renkou Xu, Wei QianAbstract:Abstract Incubation experiments with Biomass Ash (BA), bone meal (BM) and alkaline slag (AS) applied alone and together were conducted to ameliorate acidity and increase nutrient contents of five Ultisols collected from four provinces of southern China. The results showed that the ameliorating effect of the combined application of three amendments on soil acidity was greater than that of BA + BM or their single applications. The combined application of BA, BM and AS increased the pH by 0.63–1.37 for five Ultisols. The most significant decrease of soil exchangeable acidity was also observed in the treatments of BA + BM + AS by 80.1–96.9% for five Ultisols. Meanwhile, the combined application of the amendments greatly increased the exchangeable potassium, calcium and magnesium of the five soils, respectively, by 0.4–3.8, 1.9–10 and 1.7–9.7 times. The contents of available phosphorus of the five soils were also increased significantly by 0.6–184 times due to the application of BA + HBM + AS. In general, the application of the amendments did not increase available heavy metals in the soils in this short-term incubation experiment, but the potential risk of the amendments applied should be further assessed under field conditions through long-term experiments.
J Carrasco E Garcia - One of the best experts on this subject based on the ideXlab platform.
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the effect of the addition of chemical materials on the sintering of Biomass Ash
Fuel, 2008Co-Authors: M Fernandez J Llorente, Diaz P Arocas, Gutierrez L Nebot, J Carrasco E GarciaAbstract:Abstract In this work the use of chemical materials (additives) in order to reduce the Biomass Ash sintering tendency is investigated. A total of seven additives (kaolin, limestone, lime, dolomite, calcined dolomite, ophite and alumina) and silica utilised as reference material were mixed in different proportions with the Ash of five different Biomasses, and then a laboratory sintering test was performed on the mixtures to determine the effect of the additives on the sintering. The Biomasses studied in this work were: thistle Biomass, brassica carinata Biomass, barley straw, almond shell and orujillo (olive oil extraction residue). The sintering decrease among the additives was studied using X-ray diffraction. Kaolin, lime, calcined dolomite and ophite are proved to be suitable to reduce the Biomass sintering in all the considered cases. Dolomite, limestone and, particularly, the tabular alumina, offer poorer results. The dilution of the Biomass Ash is considered the main process involved in the decrease of the sintering for most of the additives, with the exception of kaolin whose chemical reactions could be more important than the dilution effect.
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suitability of thermo chemical corrections for determining gross calorific value in Biomass
Thermochimica Acta, 2008Co-Authors: M Fernandez J Llorente, J Carrasco E GarciaAbstract:The objective of this paper is to study the suitability of several laboratory methods for calculating the thermo-chemical corrections (TCCs) of acid formation, which generate extra heating during the combustion of Biomass in a calorimetric bomb. Three methods for calculating TCCs are considered in this paper: two of them are based on the titration of acidity, and the third one is based on analysing anion (nitrate, sulphate and chloride) content. This work compares the three TCCs with the composition of one coal and eight Biomass samples. TCCs based on titration are not recommended because of the neutralisation of the nitric and sulphuric acids produced during the combustion of the Biomass. The compounds contained in the Biomass Ash, such as CaCO3, are probably the cause of this neutralisation. The measurement of nitrate content in order to calculate the TCC of the formation of nitric acid was found to be the most suitable and accurate. The formation of aqueous hydrochloric acid is improbable in the biofuels considered.
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combustion in bubbling fluidised bed with bed material of limestone to reduce the Biomass Ash agglomeration and sintering
Fuel, 2006Co-Authors: M Fernandez J Llorente, Escalada R Cuadrado, J Murillo M Laplaza, J Carrasco E GarciaAbstract:Abstract A bed material of limestone was used in order to reduce/eliminate the tendency for bed material agglomeration and sintering that normally occurs in plants that operate with the traditional silica bed material. Combustion tests were carried out in a bubbling fluidised bed (BFB) combustion pilot plant (1 MWth). Mass balances of the inorganic elements and Ash characterisation with respect to bed agglomeration, fouling and emissions were performed in the BFB combustion pilot plant. Limestone bed material with particle sizes between 0.25 and 2 mm, corresponding to a mean fluidisation velocity of 1.2 m/s and at a mean bed temperature of 775 °C, were chosen. It has been successfully proven that the limestone bed material eliminates the bed agglomeration. The calcium particles, which escape from the limestone bed material and are adhered on heat exchangers, reduce the sintering of Ash deposits on the tubes.
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comparing methods for predicting the sintering of Biomass Ash in combustion
Fuel, 2005Co-Authors: M Fernandez J Llorente, J Carrasco E GarciaAbstract:Abstract The purpose of this study is to compare the suitability of five laboratory methods for predicting the Ash sintering occurring during the combustion of Biomass. The studied methods have been the following: fusibility under DIN norms, measurement of the compression strength of Ash pellet previously heated at different temperatures, manual disintegration of Biomass Ash obtained at different temperatures, relation alkaline earth oxides to alkaline oxides, and representation in a ternary phase diagram SiO2–CaO–K2O. The two last theoretical methods are based on the analysis of Biomass Ash elements. The Ash sintering behaviour results obtained with these methods for different Biomasses have been compared with the Ash sintering results obtained in combustion tests of the same Biomasses in a 1 MWth bubbling fluidised bed combustion (BFBC) pilot plant, with silica as initial bed material. The compression method does not predict adequately the Ash sintering behaviour of woody fuels and other Biomasses with a lower content in alkaline elements. The disintegration and fusibility methods predict with success the sintering behaviour of most of the tested Biomasses. Both theoretical methods have been less reliable to predict the Ash sintering behaviour than disintegration and fusibility test methods.
Laurent Van De Steene - One of the best experts on this subject based on the ideXlab platform.
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Oxidative pyrolysis of pine wood, wheat straw and miscanthus pellets in a fixed bed
Fuel Processing Technology, 2018Co-Authors: Xuan-huynh Pham, Bruno Piriou, Sylvain Salvador, Jeremy Valette, Laurent Van De SteeneAbstract:Oxidative pyrolysis is a key step in the autothermal operation of many fixed-bed reactors for staged gasification and advanced carbonisation. In these reactors, Biomass is converted into charcoal, condensates and permanent gases inside a moving Oxidation Zone (OZ) which also produces energy to self-sustain the process. Oxidative pyrolysis of three different Biomass types: pine wood, miscanthus and wheat straw pellets, was performed in a batch 20 cm diameter fixed bed reactor. Results showed that the OZ consumed 11% to 14% of the stoichiometric air to self-sustain the process and reached a peak temperature around 720 °C whatever the Biomass. The propagation velocity and thickness of the OZ were inversely proportional to the Ash content and to the bulk density of the Biomass. Ash was also shown to influence the yield and composition of the resulting products due to a catalytic effect on primary and secondary pyrolysis reactions.