The Experts below are selected from a list of 3645 Experts worldwide ranked by ideXlab platform
E. A. Popov - One of the best experts on this subject based on the ideXlab platform.
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Specific features of the stressed state arising in the high-pressure drum of a combined-cycle plant’s heat-Recovery Boiler during its startup
Thermal Engineering, 2011Co-Authors: V. A. Dvoinishnikov, E. A. PopovAbstract:Results obtained from a study of the stressed state arising in the wall of a heat-Recovery Boiler’s high-pressure drum during its startup are presented, and the effect of the pressure growth rate on the maximal stresses arising in the wall is analyzed. Recommendations for determining the optimal loading rate of the heat-Recovery Boiler are given.
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specific features of the stressed state arising in the high pressure drum of a combined cycle plant s heat Recovery Boiler during its startup
Thermal Engineering, 2011Co-Authors: V. A. Dvoinishnikov, E. A. PopovAbstract:Results obtained from a study of the stressed state arising in the wall of a heat-Recovery Boiler’s high-pressure drum during its startup are presented, and the effect of the pressure growth rate on the maximal stresses arising in the wall is analyzed. Recommendations for determining the optimal loading rate of the heat-Recovery Boiler are given.
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Specific features relating to operation of the high-pressure evaporation system of a natural-circulation heat-Recovery Boiler during its startup from the cold state
Thermal Engineering, 2010Co-Authors: V. A. Dvoinishnikov, E. A. Popov, D. A. BulychevAbstract:We study how the time taken for a gas turbine to reach the idle running mode influences the performance of each circulation loop and the entire evaporation system, and determine what specific features are pertinent to heat transfer in the heat-Recovery Boiler during its starting from the cold state.
V. A. Dvoinishnikov - One of the best experts on this subject based on the ideXlab platform.
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Specific features of the stressed state arising in the high-pressure drum of a combined-cycle plant’s heat-Recovery Boiler during its startup
Thermal Engineering, 2011Co-Authors: V. A. Dvoinishnikov, E. A. PopovAbstract:Results obtained from a study of the stressed state arising in the wall of a heat-Recovery Boiler’s high-pressure drum during its startup are presented, and the effect of the pressure growth rate on the maximal stresses arising in the wall is analyzed. Recommendations for determining the optimal loading rate of the heat-Recovery Boiler are given.
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specific features of the stressed state arising in the high pressure drum of a combined cycle plant s heat Recovery Boiler during its startup
Thermal Engineering, 2011Co-Authors: V. A. Dvoinishnikov, E. A. PopovAbstract:Results obtained from a study of the stressed state arising in the wall of a heat-Recovery Boiler’s high-pressure drum during its startup are presented, and the effect of the pressure growth rate on the maximal stresses arising in the wall is analyzed. Recommendations for determining the optimal loading rate of the heat-Recovery Boiler are given.
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Specific features relating to operation of the high-pressure evaporation system of a natural-circulation heat-Recovery Boiler during its startup from the cold state
Thermal Engineering, 2010Co-Authors: V. A. Dvoinishnikov, E. A. Popov, D. A. BulychevAbstract:We study how the time taken for a gas turbine to reach the idle running mode influences the performance of each circulation loop and the entire evaporation system, and determine what specific features are pertinent to heat transfer in the heat-Recovery Boiler during its starting from the cold state.
V. V. Ilyushin - One of the best experts on this subject based on the ideXlab platform.
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The influence of components of the type P-88 heat-Recovery Boiler of a PGU-325 power unit on the duration of starting modes
Thermal Engineering, 2011Co-Authors: Yu. A. Radin, M. S. Frolov, I. V. Krutitskii, V. V. IlyushinAbstract:Results from a study aimed at analyzing how the main critical elements of the P-88 heat-Recovery Boiler used as part of a PGU-325 power unit and the thermally stressed state of these elements influence the time taken to carry out the operations for starting the power unit.
Timo Hyppanen - One of the best experts on this subject based on the ideXlab platform.
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fouling growth modeling of kraft Recovery Boiler fume ash deposits with dynamic meshes and a mechanistic sticking approach
Fuel, 2016Co-Authors: Manuel Garcia Perez, Esa Vakkilainen, Timo HyppanenAbstract:Abstract The buildup of ash deposits represents a major challenge in the operation of industrial Boilers since it entails significant losses in heat transfer performance. Therefore, the research of predictive tools is of great value in Boiler operation. A CFD model for ash deposition and fouling growth prediction of industrial furnaces is presented. Considerations are taken regarding grid resolution and accuracy requirements available in literature. A 2D transversally-periodic bundle of four in-line tubes of a kraft Recovery Boiler bank is modeled with the gas laden with discrete solid fume ash particles. A sticking-rebound submodel determines whether to account the mass of a hitting particle for the deposit growth or to make it rebound, re-entraining it back into the flow. A dynamic mesh modifies periodically the model grid, simulating the expansion of deposits. 0.7 μm diameter particles showed round and uniform deposits caused by thermophoresis. The deposit thickness grew up to about 3 mm after 100 min of fouling. 3.62 μm particle showed more irregular distributions with some high local peaks, but lower deposition rates in average. For this particular case modeled, the constant particle sticking probability approach showed no major differences with respect to the particle sticking submodel.
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unsteady cfd analysis of kraft Recovery Boiler fly ash trajectories sticking efficiencies and deposition rates with a mechanistic particle rebound stick model
Fuel, 2016Co-Authors: Manuel Garcia Perez, Esa Vakkilainen, Timo HyppanenAbstract:Abstract This work presents a CFD model of a transversally-periodic bundle of four in-line tubes of a kraft Recovery Boiler bank for ash deposition calculations. The flue gas was laden with discrete solid ash particles. Particle contact and sticking–rebound mechanics were used. The ash deposition parameters (arrival rate, sticking efficiency, deposit rates) were computed locally, studying the dependency on the particle diameter. Emphasis was put regarding grid resolution, unsteady flow solving, and the differences observed among different tubes and locations. Thermophoresis was responsible for 94.1% of the total deposition rates for submicron (0.7 μ m ) particles, becoming markedly less significant for coarser particles. These small particles showed a much higher sticking efficiency (above 95%) than other studied particles. The particles with the largest diameter studied (18.7 μ m ) had much higher arrival rates to the cold surfaces since they did not follow the flue gas flow paths (inertial impaction). Due to their low sticking efficiency (about 15%), they formed more irregular deposition distributions. Particles with an intermediate diameter (3.62 μ m ) showed the smallest arrival rates among the three particle sizes considered.
Esa Vakkilainen - One of the best experts on this subject based on the ideXlab platform.
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Kraft Recovery Boilers – Principles and practice
2020Co-Authors: Esa VakkilainenAbstract:This book was created as postgraduate lecture notes for Lappeenranta University of Technology's special course of steam power plants. But as with anything ever written the ideas shown have nurtured for a long time. Parts of these chapters have appeared elsewhere as individual papers or work documents. One of the most helpful episodes have been presentations and discussions during Pohto Operator training seminars. Input from those sessions can be seen in chapter firing. You who run Recovery Boilers, I salute you. The purpose of this text is to give the reader an overview of Recovery Boiler operation. Most parts of the Recovery Boiler operation are common to Boilers burning other fuels. The furnace operation differs significantly from operation of other Boiler furnaces. Oxygen rich atmosphere is needed to burn fuel efficiently. But the main function of Recovery Boiler is to reduce spent cooking chemicals. Reduction reactions happen best in oxygen deficient atmosphere. This dual, conflicting nature of Recovery furnace makes understanding it so challenging. To understand the processes happening in the Recovery furnace one must try to understand the detailed processes that might occur and their limitations. Therefore chapters on materials, corrosion and fouling have been added.
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The impact of lignin removal on the dimensioning of eucalyptus pulp mills.
Appita Journal, 2020Co-Authors: Marcelo Hamaguchi, Esa Vakkilainen, Peter RyderAbstract:Lignin removal decreases the quantity of organics in pulp mill black liquor, while the inorganics remain essentially unchanged. Balances have been performed to show how lignin removal affects the sizing of different pulp mill departments and the operation of equipment. A modern South American eucalyptus pulp mill served as the base case model. This work shows that the energy balance and the Recovery Boiler operation are important factors that limit the removal rate of lignin. At 30% lignin removal, steam generation from the Recovery Boiler decreases 22%, the black liquor heating value decreases about 9% and the required Recovery Boiler capacity (in terms of dry solids flow, tDS/d) decreases by about 10%. A key calculation result shows that if the heat load into the Recovery furnace is fixed, an increase of 23% in pulp production can be achieved if 30% of lignin is removed. The simulation results show that removing lignin should be considered as one alternative for new pulp mill projects.
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11 – Recovery Boiler
Steam Generation from Biomass, 2017Co-Authors: Esa VakkilainenAbstract:This chapter introduces the kraft Recovery Boiler. A quarter of all modern biomass combustion is done in Recovery Boilers. Concentrated residue—black liquor—from chemical pulp production can, when burned, produce energy for the generation of steam and electricity. In most modern pulp mills the generated electricity is double that used by the mill.
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fouling growth modeling of kraft Recovery Boiler fume ash deposits with dynamic meshes and a mechanistic sticking approach
Fuel, 2016Co-Authors: Manuel Garcia Perez, Esa Vakkilainen, Timo HyppanenAbstract:Abstract The buildup of ash deposits represents a major challenge in the operation of industrial Boilers since it entails significant losses in heat transfer performance. Therefore, the research of predictive tools is of great value in Boiler operation. A CFD model for ash deposition and fouling growth prediction of industrial furnaces is presented. Considerations are taken regarding grid resolution and accuracy requirements available in literature. A 2D transversally-periodic bundle of four in-line tubes of a kraft Recovery Boiler bank is modeled with the gas laden with discrete solid fume ash particles. A sticking-rebound submodel determines whether to account the mass of a hitting particle for the deposit growth or to make it rebound, re-entraining it back into the flow. A dynamic mesh modifies periodically the model grid, simulating the expansion of deposits. 0.7 μm diameter particles showed round and uniform deposits caused by thermophoresis. The deposit thickness grew up to about 3 mm after 100 min of fouling. 3.62 μm particle showed more irregular distributions with some high local peaks, but lower deposition rates in average. For this particular case modeled, the constant particle sticking probability approach showed no major differences with respect to the particle sticking submodel.
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unsteady cfd analysis of kraft Recovery Boiler fly ash trajectories sticking efficiencies and deposition rates with a mechanistic particle rebound stick model
Fuel, 2016Co-Authors: Manuel Garcia Perez, Esa Vakkilainen, Timo HyppanenAbstract:Abstract This work presents a CFD model of a transversally-periodic bundle of four in-line tubes of a kraft Recovery Boiler bank for ash deposition calculations. The flue gas was laden with discrete solid ash particles. Particle contact and sticking–rebound mechanics were used. The ash deposition parameters (arrival rate, sticking efficiency, deposit rates) were computed locally, studying the dependency on the particle diameter. Emphasis was put regarding grid resolution, unsteady flow solving, and the differences observed among different tubes and locations. Thermophoresis was responsible for 94.1% of the total deposition rates for submicron (0.7 μ m ) particles, becoming markedly less significant for coarser particles. These small particles showed a much higher sticking efficiency (above 95%) than other studied particles. The particles with the largest diameter studied (18.7 μ m ) had much higher arrival rates to the cold surfaces since they did not follow the flue gas flow paths (inertial impaction). Due to their low sticking efficiency (about 15%), they formed more irregular deposition distributions. Particles with an intermediate diameter (3.62 μ m ) showed the smallest arrival rates among the three particle sizes considered.
