Figure 1. Steam molar fraction contour plots in the combined parallel
plate heat exchanger-reactor for hydrogen production by steam-methanol
reforming.
The methanol molar fraction contour plots in the combined parallel plate
heat exchanger-reactor are illustrated in Figure 2 for hydrogen
production by steam-methanol reforming. The combined heat
exchanger-reactor consists of sheets of triangularly corrugated material
laminated together so as to form a series of roughly parallel
passageways. In order for the exchanger to effectively function, the
inlet area of the exchanger utilizes a highly complicated design feature
characterized by detents and depressed crossflow passageways which
effectively causes fluid flow blockage. Consequently, this heat
exchanger possesses a high pressure drop. The method of construction
recited in the patent and exemplified by the drawings utilize long metal
welds or similar materials joining techniques resulting in a structure
highly susceptible to internal rupture, leakage and uncontrolled fluid
crossover. The combined heat exchanger-reactor consists of a monolithic
honeycomb structure wherein the channels of the honeycomb are divided
into separate groups, group one channels carrying one fluid with group
two channels carrying another fluid which differs from the first either
by composition, temperature, pressure, and direction of flow. The main
design feature of the combined heat exchanger-reactor is that one group
of channels extends outward from the honeycomb parallel to the direction
of fluid flow in the honeycomb, each channel of the group one being in
contact through common walls with channels in group two, each channel of
group one being separated from other channels of group one by the
intervening voids formed by the presence of the channels of group two.
One or both of the open ends of the group one channels are manifolded so
as to form a separation of entrances of the extended group one channels
as compared to the group two channels and the entire system is
incorporated into an outer mechanical shell so as to facilitate fluid
flow through group one and group two channels, thereby permitting the
entry or exit of fluid in group one channels while preventing entry of
such same fluid into the group two channels and thereby permitting the
independent passage of different fluids through the different channel
systems. The common walls which exist between adjacent channels of the
different groups facilitate heat transfer from one channel group to
another. The honeycomb structure, with its mutually supporting, double
cantilevered inner walls, imparts strength to the overall system
permitting the walls to be very thin and thereby being responsible for
the low weight and rapid thermal response of the combined heat
exchanger-reactor configuration. Alternatively, the manifolding of the
group one channels may be designed so as to create numerous independent
group one channel systems while still being completely surrounded by the
group two channel system, thereby permitting numerous independent
reactions to proceed simultaneously and permitting more than two
independent fluid flows to be conducted under varying conditions within
a single chemical reactor and heat exchanger system.