Application of the Generic Fluidized-Bed Reactor Model to the Fluidized-Bed Membrane Reactor Process for Steam Methane Reforming with Oxygen Input

Abstract

A generic fluidized-bed reactor model (Abba et al. Chem. Eng. Sci. 2002, 57, 4797-4807; AIChE J. 2003, in press) is adapted to evaluate the performance of a fluidized-bed membrane reactor for steam reforming with oxygen input in a large-scale unit (16 m high and 2 m wide) described by Adris and Grace (Ind. Eng. Chem. Res. 1997, 36, 4549-4556). This allows flow regimes beyond bubbling to be modeled and facilitates the treatment of the impacts of changes in volumetric flow due to variations in molar flow, temperature, and hydrostatic pressure. Improvement in the reactor performance is shown when one considers these changes. Permselective membrane tubes are shown to substantially improve the performance of the reactor. The simulation results show that an ultrathin membrane coating could result in reversal in hydrogen diffusion with height, especially at elevated temperatures. The influences on the reactor performance of several other parameters such as the superficial gas velocity and steam-to-carbon ratio are also examined. Given the right combinations of key operating parameters such as the methane-to-oxygen ratio, feed temperature, and reactor temperature, the reactor can be operated autothermally.

Membrane assisted fluidized bed reactors: Potentials and hurdles

“…Ethane dehydrogenation -Propane dehydrogenation -Cyclohexane dehydrogenation -Ethylbenzene dehydrogenation Abdalla and Elnashaie, 1995 Water-gas shift reaction -Methane steam reforming Abba et al, 2003;Adris et al, 1991Adris et al, , 1994aAdris and Grace, 1997;Chen et al, 2003a,b,c;Elnashaie, 2004a,b, 2005a,b,c;Gobina, 2000;Grace et al, 2001;Patil et al, 2005;Prasad and Elnashaie, 2002;Rakib and Alhumaizi, 2005 Methane partial oxidation to synthesis gas Mleczko et al, 1996;Ostrowski et al, 1998aOstrowski et al, ,b, 1999 Selectivity enhancement Oxidative coupling of methane -Partial oxidation of ethane to ethene Ahchieva et al, 2005 Ethylene epoxidation -Partial oxidation of propane to propene Alonso et al, 2005 Partial oxidation of propane to acrolein -Partial oxidation of butane to maleic anhydride Alonso et al, 2001 Partial oxidation of butene to methacrolene -Partial oxidation of methanol to formaldehyde Deshmukh et al, 2005a,b,c CO hydrogenation to hydrocarbons -Oxidative dehydrogenation of ethylbenzene - 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Year Number of publications Our paper is based on a database search for the years 1965-2005 with the software SciFinder Scholar (2004) and with keywords "Fluidized beds and membranes". The obtained number of publications per year is plotted for the past 15 years in Fig.…”

“…Adris et al (1991Adris et al ( , 1994a demonstrated that for steam reforming of natural gas the thermodynamic equilibrium restrictions can be overcome by in situ separation and removal of hydrogen via perm-selective thin-walled palladiumbased membranes leading to increased synthesis gas yields in comparison to the industrial fixed bed steam reformer. Subsequently, Grace and co-workers (Roy et al, 1999;Grace et al, 2001;Abba et al, 2003) and Elnashaie and co-workers (Chen et al, 2003a,b,c;Prasad and Elnashaie, 2002) added oxygen into these steam reforming reactors for in situ generation of heat by partial oxidation of methane to supply the energy for the endothermic reforming reaction. Prasad and Elnashaie (2002) used CO 2 sequestration using CO 2 -lime reaction to assist/replace the hydrogen perm-selective membranes.…”

“…In another study, Abba et al (2003) adapted a generalized fluidized bed reactor model developed by them (Abba et al, 2002) to fluidized bed membrane reactor process for steam reforming of methane with oxygen addition in a large scale unit (16 m high and 2 m wide) described by Adris and Grace (1997). This approach allowed flow regimes beyond bubbling to be modelled and facilitated the treatment of the impacts of changes in volumetric flow due to variations inmolar flow, temperature, and hydrostatic pressure.…”

Gas and particle circulation in an internally circulating fluidized bed membrane reactor cold model

“…Several reactor models (e.g. Abba et al, 2003;Chen et al, 2003;Dogan et al, 2003;Grace et al, 2001;Patil et al, 2007) have also been developed to simulate FBMR processes. Experimental studies in a commercial FBMR unit were reported by Chen et al (2007).…”

Simulation of autothermal reforming in a staged‐separation membrane reactor for pure hydrogen production

“…One option is to employ fluidized-beds to augment mass and heat transfer (Chen, 2002;Abba et al, 2003;Chen and Elnashaie, 2004;Boyd et al, 2005;Grace et al, 2005;Patil et al, 2005Patil et al, , 2006Patil et al, , 2007Rakib and Alhumaizi, 2005;Abashar et al, 2007;Deshmukh et al, 2007). Another is to introduce membrane separation.…”