Lars-André Tokheim
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View article: Electrified externally heated rotary calciner for calcination of cement raw meal
Electrified externally heated rotary calciner for calcination of cement raw meal Open
The cement industry can reduce its CO2 emissions by electrifying the calciner. It can avoid emissions from fuel combustion and produce pure CO2 from the calcination reaction (CaCO3 → CaO + CO2) for direct capture. A differential-algebraic …
View article: CPFD simulation of an electrically heated fluidized bed calciner with binary particles
CPFD simulation of an electrically heated fluidized bed calciner with binary particles Open
Electrifying a calciner with clean energy can cut fuel emissions and produce a stream of relatively pure CO2 from the calcination reaction (CaCO3 → CaO + CO2), which can be utilized or stored. A fluidized bed calciner offers a high heat tr…
View article: Novel design of a rotary calciner internally heated with electrical axial heaters: Experiments and modelling
Novel design of a rotary calciner internally heated with electrical axial heaters: Experiments and modelling Open
As the share of renewable energy increases, green electricity may help reduce the carbon footprint in the lime industry. Electrifying the calciner can produce relatively pure CO2 from the calcination process (CaCO3 → CaO + CO2), which may …
View article: Electrified calciner concept for CO2 capture in pyro-processing of a dry process cement plant
Electrified calciner concept for CO2 capture in pyro-processing of a dry process cement plant Open
Around two-thirds of the CO2 emission from the cement industry comes from calcite decomposition (CaCO3 → CaO + CO2), and most of this reaction happens in the calciner. So, it is possible to reduce the CO2 emission significantly by electrif…
View article: Opportunities and challenges of using SRF as an alternative fuel in the cement industry
Opportunities and challenges of using SRF as an alternative fuel in the cement industry Open
Over two billion tonnes of municipal solid wastes (MSW) are generated annually from households, industrial facilities, and commercial sites. The non-hazardous fraction of MSW is used to produce solid recovered fuels (SRF), which have an ec…
View article: Comparison of Experimental Results from Operating a Novel Fluidized Bed Classifier with CFD Simulations Applying Different Drag Models and Model Validation
Comparison of Experimental Results from Operating a Novel Fluidized Bed Classifier with CFD Simulations Applying Different Drag Models and Model Validation Open
A cold-flow lab-scale cross-flow fluidized bed classifier was simulated using the CFD software Barracuda VR®. The purpose of the study was to identify the most suitable drag model and make the model adjustments that provide the best repres…
View article: CPFD simulation of enhanced cement raw meal fluidization through mixing with coarse, inert particles
CPFD simulation of enhanced cement raw meal fluidization through mixing with coarse, inert particles Open
In the current work, computational particle and fluid dynamics (CPFD) simulations are used to study an electrically heated bubbling fluidized bed (BFB) used as a calciner in a cement manufacturing process, applying a binary-particle fluidi…
View article: A new Approach for Scaling Up from a Small Cold to a Large Hot Bed for Biomass Conversion in a Bubbling Fluidized Bed Reactor
A new Approach for Scaling Up from a Small Cold to a Large Hot Bed for Biomass Conversion in a Bubbling Fluidized Bed Reactor Open
Bubbling fluidized beds are simple and attractive means of achieving efficient conversion of biomass if particle segregation and the associated effects are minimized.To improve the knowledge of fluidized bed reactor design, this paper comp…
View article: Fluidized bed calcination of cement raw meal: Laboratory experiments and CPFD simulations
Fluidized bed calcination of cement raw meal: Laboratory experiments and CPFD simulations Open
The chemical and thermal processes associated with the decarbonation and fuel combustion in the cement kiln process produce a large amount of carbon dioxide (CO2) contributing with around 8 % of the global CO2 emissions.Utilizing green ele…
View article: Detailed One-Dimensional Model for Steam-Biomass Gasification in a Bubbling Fluidized Bed
Detailed One-Dimensional Model for Steam-Biomass Gasification in a Bubbling Fluidized Bed Open
A one-dimensional unsteady state model is developed for simulation of biomass gasification in a bubbling fluidized bed. The proposed model accounts for the effect of hydrodynamic behavior of the fluidized bed by incorporating the momentum …
View article: Measurement and characterization of biomass mean residence time in an air-blown bubbling fluidized bed gasification reactor
Measurement and characterization of biomass mean residence time in an air-blown bubbling fluidized bed gasification reactor Open
Gasification of biomass in bubbling fluidized beds can be limited by accumulation of unconverted char particles during the process. The amount of unconverted biomass depends on the residence time of the fuel particles. This study demonstra…
View article: Behaviour of biomass particles in a bubbling fluidized bed: A comparison between wood pellets and wood chips
Behaviour of biomass particles in a bubbling fluidized bed: A comparison between wood pellets and wood chips Open
For successful operation and design of a bubbling fluidized bed reactor handling a specific biomass, in-depth knowledge about the bed behaviour is paramount. This study compares the behaviour of a bed of sand containing wood pellets with t…
View article: Combined calcination and CO2 capture in cement clinker production by use of electrical energy
Combined calcination and CO2 capture in cement clinker production by use of electrical energy Open
The technical feasibility of electrifying the calcination process in a precalciner cement kiln system was assessed by studying different electrification concepts. Resistance-based heating was selected as it requires no CO2 recycling, has a…
View article: Impact of Particle Diameter, Particle Density and Degree of Filling on the Flow Behavior of Solid Particle Mixtures in a Rotating Drum
Impact of Particle Diameter, Particle Density and Degree of Filling on the Flow Behavior of Solid Particle Mixtures in a Rotating Drum Open
Two-dimensional CFD simulations were performed to investigate the impact of density, particle diameter and degree of filling on the flow behavior of a solid particle mixture in a transverse plane of a rotary drum.The Eulerian approach with…
View article: Mixing and Segregation of two Particulate Solids in the Transverse Plane of a Rotary Kiln
Mixing and Segregation of two Particulate Solids in the Transverse Plane of a Rotary Kiln Open
Mixing of two granular phases in a rotary kiln was investigated through CFD simulations using a twodimensional transverse plane based on the Eulerian approach and the kinetic theory of granular flows.Simulations were performed transverse w…
View article: Improved models for predicting bubble velocity, bubble frequency and bed expansion in a bubbling fluidized bed
Improved models for predicting bubble velocity, bubble frequency and bed expansion in a bubbling fluidized bed Open
An efficient design and operational control of a fluidized bed reactor relies on accurate prediction of bubble properties. This paper employs measurement of bed void fraction in determining the bubble velocity in a given bed. An analytical…
View article: Experimental Study of Thermal and Catalytic Pyrolysis of Plastic Waste Components
Experimental Study of Thermal and Catalytic Pyrolysis of Plastic Waste Components Open
Thermal and catalytic pyrolysis of virgin low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP) and mixtures of LDPE/PP were carried out in a 200 mL laboratory scale batch reactor at 460 °C in a nitrogen atm…
View article: Waste heat availability in the raw meal department of a cement plant
Waste heat availability in the raw meal department of a cement plant Open
The main aim of this study was to determine the available heat in the cement kiln exhaust gas subject to different process conditions. A Norwegian cement plant producing about 1.3 million tons of cement per year was used as a case study. A…
View article: Numerical modeling of the calcination process in a cement kiln system
Numerical modeling of the calcination process in a cement kiln system Open
The calcium carbonate decomposition into calcium oxide and carbon dioxide is a key process step in a cement kiln.The reaction requires thermal energy input, and pulverized coal is the fuel typically used for this purpose in the cement indu…
View article: Comparison of the influence of drag models in CFD simulation of particle mixing and segregation in a rotating cylinder
Comparison of the influence of drag models in CFD simulation of particle mixing and segregation in a rotating cylinder Open
CFD modelling was used to simulate particle segregation in a transverse plane of a rotating cylinder under different particle-particle drag models.The Eulerian method was used to model the dense particulate phases in the system.Two types o…
View article: SUBSTITUTION OF COAL BY REFUSE DERIVED FUELS (RDF) IN THE PRECALCINER OF A CEMENT KILN SYSTEM
SUBSTITUTION OF COAL BY REFUSE DERIVED FUELS (RDF) IN THE PRECALCINER OF A CEMENT KILN SYSTEM Open
Cement manufacturing is an energy intensive process where coal is the main energy source.Replacement of coal with refuse derived fuels (RDF) will reduce costs and CO2 emissions as RDF is partly carbon neutral.In modern cement kilns, most o…
View article: Determination of onset of bubbling and slugging in a fluidized bed using a dual-plane electrical capacitance tomography system
Determination of onset of bubbling and slugging in a fluidized bed using a dual-plane electrical capacitance tomography system Open
For a successful application of fluidized beds in chemical reactions and solids circulation, the boundary of regime of operation such as bubbling and slugging regimes, needs to be clearly defined. This study provides a method for determini…
View article: Aspen Plus® Process Simulation of Calcium Looping with Different Indirect Calciner Heat Transfer Concepts
Aspen Plus® Process Simulation of Calcium Looping with Different Indirect Calciner Heat Transfer Concepts Open
CO2 reduction has become an urgent need due to the greenhouse effect. Scientists working on the topic agree that the major cause of global warming is greenhouse gases emitted due to human activities. Burning of fossil fuels is one of the m…
View article: Experimental Study and CFD Modelling of Minimum Fluidization Velocity for Geldart A, B and D Particles
Experimental Study and CFD Modelling of Minimum Fluidization Velocity for Geldart A, B and D Particles Open
The aim of this study is to determine minimum fluidization velocity of three different particles which represent different Geldart classification groups and to compare the results with computational results. The experiments were conducted …