Use of a heterogeneous two-dimensional model to improve the primary steam reformer performance

Solar steam reforming of natural gas for hydrogen production using molten salt heat carriers

“…(1) steady-state conditions; (2) plug flow behavior; (3) pseudohomogeneous catalyst bed; (4) pseudoeffectiveness factors g 1 , g 2 , and g 3 for the reactions (1), (2) and (3) independent of local conditions and fixed at 0.02 as an average value of those reported in the literature [22][23][24] ; (5) ideal gas behavior. It has been demonstrated that the one-dimensional nature of the model does not lead to significant errors compared with a similar two-dimensional approach.…”

Operation of an industrial steam reformer under severe condition: A simulation study

“…They emphasized, however, on the usefulness of such models for the prediction of carbon free operating conditions. De Deken et al (1982) only compared the results obtained from a heterogeneous one-dimensional model with a two-dimensional one, while in a more recent study Pedenera et al (2003) used their heterogeneous two-dimensional model for proposing some theoretical improvements which may influence the primary reformer performance in a good manner. However, their model predicted a very large radial gradient, more than 100…”

“…An apparent mistake seen in published works is the assumption at which the outside tube skin temperature is considered to be identical for both oneand two-dimensional models (De Deken et al, 1982;Pedenera et al, 2003). This is clearly a false assumption, because there is a substantial temperature difference between the average fluid temperature in one-dimensional models and the fluid temperature flowing near the inner wall of tubes in two-dimensional models, particularly in the first half length of reformer tubes.…”

Thermal modeling of radiation and convection sections of primary reformer of ammonia plant

“…6. The ratio of tube center-to-center distance to the tube outside diameter (B) has important influence on the performance of primary reformer [8]. The fraction of radiation incident on the tube plane, that is, intercepted by the tubes, the so-called F factor is a function of parameter B, so that an increase in B, decreases factor F. A decrease in factor F proportionally affects the effective radiative emissivity coefficient (e eff ), radiation heat transfer coefficient (g rad ) and subsequently decreases the heat transfer from combustion gases to the tube walls ð _ Q s Þ.…”