scholarly journals A simple model for desulphurisation of flue gas using reactive filters

2021 ◽  
Vol 129 (1) ◽  
Author(s):  
Chris Breward ◽  
Kristian Kiradjiev
Keyword(s):  
Sulphuric Acid ◽  
Flue Gas ◽  
Sulphur Dioxide ◽  
Numerical Solutions ◽  
Relevant Parameter ◽  
Asymptotic Results ◽  
Catalyst Structure ◽  
Outer Flow ◽  
Dimensionless Parameters ◽  
Porous Catalyst

AbstractDesulphurisation of flue gas is essential before it can be released safely into the atmosphere. One way of removing sulphur dioxide is to use a purification device incorporating a reactive filter, in which the flue gas stream passes in front of a porous-catalyst-filled structure which converts the gaseous sulphur dioxide into liquid sulphuric acid. In this paper, we build and solve a simple mathematical model to describe the operation of a paradigm reactive filter. Our model captures the transport of sulphur dioxide through the device via advection in the main “outer” flow and diffusion through the catalyst structure along with the production of sulphuric acid. This sulphuric acid gradually accumulates in the filter rendering it less efficient. We determine the clogging time for an individual channel (that is, the time at which the entrance to the channel becomes completely filled with liquid) and explore how the concentrations of sulphur dioxide and oxygen and the thickness of the sulphuric acid layer change as the key dimensionless parameters are varied, comparing numerical and asymptotic results where appropriate. We then turn our attention to the device scale and solve our model numerically to determine the overall lifetime of the device. We vary the key dimensionless parameters and explore how they affect the efficiency of the device. In the physically relevant parameter regime, we find an explicit solution to the outer flow problem which agrees well with numerical solutions and provides a formula for the lifetime of the device. Finally, we propose a formula for determining the catalyst reaction rate, given data on the concentration of sulphur dioxide exiting the device.

scholarly journals Modelling and Multi-Objective Optimization of the Sulphur Dioxide Oxidation Process

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1072
Author(s):  
Mohammad Reza Zaker ◽  
Clémence Fauteux-Lefebvre ◽  
Jules Thibault
Keyword(s):  
Sulphuric Acid ◽  
Sulphur Dioxide ◽  
Variable Number ◽  
Inlet Temperature ◽  
Multi Objective Optimization ◽  
Absorption Column ◽  
Maximum Reaction Rate ◽  
Multi Objective ◽  
Maximum Reaction

Sulphuric acid (H2SO4) is one of the most produced chemicals in the world. The critical step of the sulphuric acid production is the oxidation of sulphur dioxide (SO2) to sulphur trioxide (SO3) which takes place in a multi catalytic bed reactor. In this study, a representative kinetic rate equation was rigorously selected to develop a mathematical model to perform the multi-objective optimization (MOO) of the reactor. The objectives of the MOO were the SO2 conversion, SO3 productivity, and catalyst weight, whereas the decisions variables were the inlet temperature and the length of each catalytic bed. MOO studies were performed for various design scenarios involving a variable number of catalytic beds and different reactor configurations. The MOO process was mainly comprised of two steps: (1) the determination of Pareto domain via the determination a large number of non-dominated solutions, and (2) the ranking of the Pareto-optimal solutions based on preferences of a decision maker. Results show that a reactor comprised of four catalytic beds with an intermediate absorption column provides higher SO2 conversion, marginally superior to four catalytic beds without an intermediate SO3 absorption column. Both scenarios are close to the ideal optimum, where the reactor temperature would be adjusted to always be at the maximum reaction rate. Results clearly highlight the compromise existing between conversion, productivity and catalyst weight.

scholarly journals Two dimensionless parameters and a mechanical analogue for the HKB model of motor coordination

2021 ◽  
Author(s):  
J. F. Cass ◽  
S. J. Hogan
Keyword(s):  
Motor Coordination ◽  
Nonlinear Damping ◽  
Numerical Continuation ◽  
Arbitrary Parameter ◽  
Relevant Parameter ◽  
Coupling Coefficients ◽  
Dimensionless Parameters ◽  
Biologically Relevant ◽  
Mechanical Analogue ◽  
Partner Interaction

AbstractThe widely cited Haken–Kelso–Bunz (HKB) model of motor coordination is used in an enormous range of applications. In this paper, we show analytically that the weakly damped, weakly coupled HKB model of two oscillators depends on only two dimensionless parameters; the ratio of the linear damping coefficient and the linear coupling coefficient and the ratio of the combined nonlinear damping coefficients and the combined nonlinear coupling coefficients. We illustrate our results with a mechanical analogue. We use our analytic results to predict behaviours in arbitrary parameter regimes and show how this led us to explain and extend recent numerical continuation results of the full HKB model. The key finding is that the HKB model contains a significant amount of behaviour in biologically relevant parameter regimes not yet observed in experiments or numerical simulations. This observation has implications for the development of virtual partner interaction and the human dynamic clamp, and potentially for the HKB model itself.

A sufficient condition for the instability of columnar vortices

1983 ◽  
Vol 126 ◽  
pp. 335-356 ◽  
Author(s):  
S. Leibovich ◽  
K. Stewartson
Keyword(s):  
Numerical Solutions ◽  
Three Dimensional ◽  
Azimuthal Velocity ◽  
Unstable Wave ◽  
Sufficient Condition ◽  
Asymptotic Results ◽  
Specific Flow ◽  
Columnar Vortex ◽  
Swirl Velocity ◽  
Inviscid Instability

The inviscid instability of columnar vortex flows in unbounded domains to three-dimensional perturbations is considered. The undisturbed flows may have axial and swirl velocity components with a general dependence on distance from the swirl axis. The equation governing the disturbance is found to simplify when the azimuthal wavenumber n is large. This permits us to develop the solution in an asymptotic expansion and reveals a class of unstable modes. The asymptotic results are confirmed by comparisons with numerical solutions of the full problem for a specific flow modelling the trailing vortex. It is found that the asymptotic theory predicts the most-unstable wave with reasonable accuracy for values of n as low as 3, and improves rapidly in accuracy as n increases. This study enables us to formulate a sufficient condition for the instability of columnar vortices as follows. Let the vortex have axial velocity W(r), azimuthal velocity V(r), where r is distance from the axis, let Ω be the angular velocity V/r, and let Γ be the circulation rV. Then the flow is unstable if $ V\frac{d\Omega}{dr}\left[ \frac{d\Omega}{dr}\frac{d\Gamma}{dr} + \left(\frac{dW}{dr}\right)^2\right] < 0.$

Purification Route of Pyrite from Coal Mining

2016 ◽  
Vol 869 ◽  
pp. 155-158
Author(s):  
Camila Machado de Oliveira ◽  
Adilson Oliveira ◽  
Jeane Almeida do Rosário ◽  
Agenor de Noni Jr. ◽  
Michael Peterson
Keyword(s):  
Solar Cells ◽  
Organic Solvent ◽  
Solid Waste ◽  
Coal Mining ◽  
Sulphuric Acid ◽  
Sulphur Dioxide ◽  
Hot Water ◽  
Soluble Salts ◽  
It Use ◽  
Purity Level

Pyrite, mineral largely found in nature, is considered a solid waste when is obtained from the coal mining. However, can be precursor of products like: sulphur, sulphuric acid, hematite, sulphur dioxide, fertilizers and iron sulfates. Several studies also point it property of semiconduction and it use in solar cells. Increase it purity level is important for transforming it in products with more aggregate value. Thus, the present work suggests a purification route for the reduction in soluble salts in water, organics and quartz associated with pyrite from the coal mining beneficiation. The used methods were solubilization in hot water and in organic solvent (dichloromethane). Were applied XRD, FTIR, total sulphur determination, and gas helium picnometry. Comparing the results obtained for the “in nature” pyrite with the purified one, proved the efficiency of the proposed method.

Mortality and cancer morbidity in workers exposed to sulphur dioxide in a sulphuric acid plant

1988 ◽  
Vol 61 (3) ◽  
pp. 157-162 ◽  
Author(s):  
Viveka Englander ◽  
Allan S�berg ◽  
Lars Hagmar ◽  
Robyn Attewell ◽  
Andrejs Sch�tz ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Sulphur Dioxide ◽  
Acid Plant ◽  
Cancer Morbidity

scholarly journals Rayleigh-type waves on a coated elastic half-space with a clamped surface

2019 ◽  
Vol 377 (2156) ◽  
pp. 20190111 ◽  
Author(s):  
J. Kaplunov ◽  
D. Prikazchikov ◽  
L. Sultanova
Keyword(s):  
Half Space ◽  
Numerical Solutions ◽  
Substrate Surface ◽  
Numerical Data ◽  
Elastic Half Space ◽  
Asymptotic Results ◽  
Homogeneous Half Space ◽  
Upper Face ◽  
Localized Waves ◽  
Perturbed Equation

Elastodynamics of a half-space coated by a thin soft layer with a clamped upper face is considered. The focus is on the analysis of localized waves that do not exist on a clamped homogeneous half-space. Non-traditional effective boundary conditions along the substrate surface incorporating the effect of the coating are derived using a long-wave high-frequency procedure. The derived conditions are implemented within the framework of the earlier developed specialized formulation for surface waves, resulting in a perturbation of the shortened equation of surface motion in the form of an integral or pseudo-differential operator. Non-uniform asymptotic formula for the speeds of the sought for Rayleigh-type waves, failing near zero frequency and the thickness resonances of a layer with both clamped faces, follow from the aforementioned perturbed equation. Asymptotic results are compared with the numerical solutions of the full dispersion relation for a clamped coated half-space. A similarity with Love-type waves proves to be useful for interpreting numerical data. This article is part of the theme issue ‘Modelling of dynamic phenomena and localization in structured media (part 1)’.

A Change in Wave Type Modeled by the Variable Coefficient Korteweg-deVries Equation

1985 ◽  
Vol 52 (4) ◽  
pp. 752-758 ◽  
Author(s):  
M. S. Cramer ◽  
S. H. Nguyen ◽  
M. E. Bowman ◽  
B. E. McCown
Keyword(s):  
Variable Coefficient ◽  
Burger Equation ◽  
Numerical Solutions ◽  
Asymptotic Results ◽  
Wave Type ◽  
Initial Shape ◽  
Depth Variation ◽  
Initial Wave ◽  
Near Shore ◽  
Wave Slope

Strongly shoaling solutions to the variable coefficient Korteweg-deVries equation have been obtained for arbitrary initial or off-shore waveforms and depth variations. Although the solutions were capable of exhibiting dispersive behavior off-shore, the near-shore behavior was always found to be governed by a variable coefficient Burger equation. Conditions under which the wave slope became infinite were given in terms of the initial shape of the wave and the depth variation. These solutions are valid when α < < δ < < 1, where α is the ratio of the initial wave amplitude to the depth and δ is the ratio of the initial length of the wave to the length scale associated with the depth variation. Numerical solutions of this equation were also found; these were in excellent agreement with the asymptotic results.

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