Operating Conditions for a Transpiring Wall Reactor for Supercritical Water Oxidation

Abstract

The synthesis of diethylacetal from ethanol and acetaldehyde catalysed by the acid resin Amberlyst 18 (Rohm and Haas) is considered. The adsorption and reaction experiments were performed in a laboratory scale fixed bed adsorptive reactor, operating isothermally at 15 C and at atmospheric pressure. The experimental results of dynamic adsorption of binary non-reactive mixtures are reported and used to obtain multicomponent adsorption equilibrium isotherms Langmuir type. The reaction kinetics reported in a previous paper was used in the model of the adsorptive reactor which was able to predict the experimental behaviour of the system.A novel multifunctional reactor concept for steam reforming is presented which integrates feed evaporation, steam reforming and water-gas-shift reaction into a countercurrent parallel plate reactor. The necessary heat for the endothermic steam reforming and the feed evaporation is supplied by catalytic combustion of a hydrogen containing off-gas which takes place in every second channel. For the evaluation of the reactor concept a laboratory reactor for a hydrogen production equivalent to 1 kW thermally was built up and tested against a conventional fixed bed reactor with separate feed evaporation.Computational fluid dynamic simulations have been used for a parameter analysis of a simplified tubular transpiring wall reactor used for supercritical water oxidation. The objectives were a corrosion and plugging free condition at the wall and a plug flow behaviour of the bulk. The parameter varied are temperature and mass flow of the bulk flow of water as well as temperature and mass flux through the transpiring wall. The minimal transpiration flux is given by the ability of the transpiration flux to protect the wall against any adherence of salt particles precipitated in the bulk flow. Bulk temperature and flow rate showed little influence but the lower limit of the temperature and the upper limit of the flux are restricted by the need to prevent natural convection in the reactor. Figure.Side view of reactor.658 R e a c t i o n E n g i n e e r i n g Chemie Ingenieur Technik (73) 6 I 2001

Impact of non-ideality on mixing of hydrocarbons and water at supercritical or near-critical conditions

“…In the literature, two methodologies have been utilized: 1) modeling turbulent mixing in the absence of phase boundaries [5][6][7][8][9][10][11][12][13], and 2) microscale modeling of individual droplets immersed in supercritical or near-critical fluids [1,2,[14][15][16][17][18][19][20][21][22]. The former applies only to fully miscible conditions.…”

“…Prior studies [1,2,5,7,[9][10][11][12][13][18][19][20][21] used the ideal fluid model in computing the diffusive driving force, although the equation of state, thermodynamic and transport properties, etc., took account of the non-ideality in these studies. On the other hand, the following numerical studies used the non-ideal driving force for SCF mixtures.…”

Supercritical Water Gasification of Municipal Sludge: A Novel Approach to Waste Treatment and Energy Recovery

“…Most commercial and industrial applications require that engineering designs and materials overcome corrosion and plugging problems and that systems operate on a continuous duty cycle (Azadi et al, 2011;Elliott, 2008;Guo et al, 2007). Some common, SCW-reactor considerations are presented here, while extensive and detailed reviews can be found elsewhere (Bermejo et al, 2005a(Bermejo et al, , 2005b(Bermejo et al, , 2009Calzavara et al, 2004;Fauvel et al, 2003Fauvel et al, , 2005Lieball et al, 2001;Machida et al, 2011;Marrone & Hong, 2009;Mitton et al, 2000;Peter, 2004;Tan et al, 2011;Veriansyah et al, 2009;Wellig et al, 2005;Yoshida & Matsumura, 2009). …”

Operating characteristics of a transpiring-wall SCWO reactor with a hydrothermal flame as internal heat source

“…Therefore, a novel tubular reactor type with a hydrothermal burner and transpiring-wall technology has been developed and investigated during the last few years [43][44][45][46][47][48].…”

“…Therefore, temperature profiles were measured using special intermediate rings between the individual transpiring-wall elements. Finally, these experiments provided data for the validation of turbulent reactive computational fluid dynamic (CFD) models [44,46,48].…”