The Fischer‐Tropsch synthesis carried out in a slurry bubble column is modeled with a focus on the production of liquid fuels from biomass. Mass, momentum and energy balances are formulated for the gas, liquid and solid phases and solved by the orthogonal collocation method. A multifluid population balance model is utilized. The interfacial area between the gas and liquid phases can be calculated directly from a mass density function of the bubbles. Five different compositions of feed synthesis gas representing biomass (with and without water‐gas shift reaction), coal (with and without autothermal reforming), and natural gas (after autothermal reforming) are simulated to highlight the effect of the synthesis gas composition.

Modeling of reactive dispersed flows with interfacial mass transfer limitations require an accurate description of the interfacial area, mass transfer coefficient and the driving force. The driving force is given by the difference in species composition between the continuous and dispersed phases and thus depends on bubble size. This paper shows the extension of the multifluid-PBE model to reactive and nonisothermal flows with novel transport equations for species mass and temperature which are continuous functions of bubble size. The model is demonstrated by simulating the Fischer-Tropsch synthesis operated in a slurry bubble column at industrial conditions. The simulation results show different composition and velocity for the smallest and largest bubbles. The temperature profile was independent on bubble size due to efficient heat exchange. The proposed model is particularly useful in investigating the effects of bubble size on strongly mass transfer limited processes Email addresses: camilla.berge.vik@ntnu.no (Camilla Berge Vik), jannike.solsvik@ntnu.no (Jannike Solsvik), magne.hillestad@ntnu.no (Magne Hillestad), hugo.a.jakobsen@ntnu.no (Hugo A. Jakobsen)

At high catalyst volume fractions the Fischer-Tropsch synthesis (FTS) operated in a slurry bubble column (SBC) is driven into the mass transfer limited regime. This study utilized literature models for the gas-liquid mass transfer coefficients in a multifluid-population balance model in which the gas-phase composition was a function of bubble size. The results confirmed that mass transfer limitations occur and that the choice of mass transfer coefficient model is crucial, yielding final conversion results ranging from 45% to 92% depending on the choice of k L models. At smaller k L values the composition is highly dependent on bubble size, whilst for the largest k L values the composition is not a function of bubble size at all. The population balance modeling (PBM) allowed for explicitly keeping track of the bubble size distribution. Varying the inlet Sauter-mean diameter (SMD) resulted in a linear decrease in conversion as the inlet SMD was increased from 5 mm to 20 mm. Illustrative models for the bubble size dependency of k L were implemented, which provided additional information compared to traditional models which use (bubble size) averaged values for the liquid-phase mass transfer coefficient k L and/or the gas-liquid interfacial area

The French natural philosopher Henri Victor Regnault (1810–1878) was one of many researchers who contributed to the development of the thermometer in the 19th century. In this paper, we use an example from Regnault’s work to explore how the history of thermometry can provide a context for teaching upper-secondary chemistry students about the nature of science (NOS), particularly its aims and values. The study takes form as a hermeneutical spiral, wherein literature on the history and philosophy of science, NOS, the family resemblance approach (FRA), NOS teaching, characteristics of narratives, and the new performative paradigm feed into the spiral, along with input from an empirical study. A teaching unit (n = 21, duration = 90 min) was developed and tested on Norwegian students aged 17–18 years, and a thematic analysis of students’ statements (n = 13) was carried out. The students identified “being first,” “usefulness,” “accuracy,” and “minimalism” as values and aims that guided Regnault’s work. We argue that the use of this particular historical episode framed within FRA (1) invited students to identify with the human actor—Regnault, (2) invited students into the historical context of the development of the thermometer, and (3) demonstrated complexity and provided context to support students’ own construction of their understanding of NOS. To summarize, by deriving the term “research with” from the performative paradigm and using the context of the historical episode related to the thermometer within the FRA framework students were invited to research with Henri Regnault.

A structural analysis performed by Scandpower combining explosion simulations and structural analysis utilising the the computer tools USFOS and FLACS is described. As of today, the most common procedure for elastic and plastic explosion response analyses is to define the explosion load as a uniform pressure vs. time function for all surfaces and elements in the model. Capabilities of the computer tools FLACS and USFOS allow for a more refined approach, recognizing that for large geometries explosion pressure will vary in both time and spatial domain.USFOS (Ultimate Strength for Offshore Structures) (Ref. /1/) is a leading computer program for nonlinear static and dynamic analysis of space frame structures. The program accurately simulates the collapse process, from the initial yielding, through to the formation of a complete collapse mechanism and the final toppling of the structure. FLACS (FLame ACcellerator Simulator) (Ref. /2, 3/) is a computational fluid dynamics (CFD) tool for modeling of ventilation, gas dispersion and explosions in complex process areas. The FLACS code allows for monitoring pressures at user defined surface areas, which can be chosen to correspond with an USFOS model. 1