Computation of Reaction Flows in Microreactors

Any notable accumulation of gas was unlikely since the two fans inside the chassis create a flow rate of approximately 180 CFM of air through the system. This corresponded to more than 95 complete air changes or turnovers every minute (Heck and Manning, 2000). The most likely zone of gas escape would be above the microreactor due to a membrane failure. If this occurs, the control system should have interlocked and shutoff the flow of combustible gas to that reaction channel. The flammable gas that does escape would have been immediately diluted by air flowing over the microreactor at an estimated rate of 120 ft min (Heck and Manning, 2000). To provide a more detailed analysis of gas mixing in the immediate vicinity of a microreactor die, a computational fluid dynamics (CFD) model was constructed to simulate the gas flow hydrodynamics. This simulation quantifies that there is a recirculation zone above the reactor with an airflow rate... 

Another erample involves the design of a gas-phase microreactor system for the OTddation of CH4 and NH3 ]65]. The system utilizes the fabrication, assembly, and system integration principles from the computer industry. The reactor boards consist of several reactor channels and control functions for the gas flow rate and reaction temperature (Figure 11.13). The different reactor boards are highly modular and fit in the slots of a computer framework. 

The heart of the system is a microreactor packaging scheme that is based upon a commercially available microchip socket. This approach allows the silicon-based reactor die, which contains dual parallel reaction channels with more than 100 electrical contacts, to be installed and removed in a straightforward fashion without removing any fluidic and electronic connections. Various supporting microreactor functions, such as gas feed flow control, gas feed mixing, and various temperature control systems, are mounted on standard CompactPCI electronic boards. The boards are subsequently installed in a commercially available computer chassis. Electrical connections between the boards are achieved through a standard backplane and custom-built input-output PC boards. A National Instruments embedded real-time processor is used to provide closed-loop process control and... 

In this contribution, we present computer analyses of several selected temperature-programmed desorption (TPD) and temperature-programmed surface reaction (TPSR) experiments in a microreactor flow system operating under atmospheric pressure. The continuous stirred tank reactor (CSTR) and plug flow reactor (PFR) models have been applied for the design equation as... 

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