U.S. patent application number 11/448349 was filed with the patent office on 2006-10-12 for methods for using parallel flow reactor having improved thermal control.
This patent application is currently assigned to Symyx Technologies, Inc.. Invention is credited to H. Sam Bergh, James R. Engstrom, Shenheng Guan, Steffen Hardt, Astrid Lohf, Frank Michel.
Application Number | 20060228276 11/448349 |
Document ID | / |
Family ID | 26788677 |
Filed Date | 2006-10-12 |
United States Patent
Application |
20060228276 |
Kind Code |
A1 |
Bergh; H. Sam ; et
al. |
October 12, 2006 |
Methods for using parallel flow reactor having improved thermal
control
Abstract
Parallel flow chemical processing systems, such as parallel flow
chemical reaction systems are disclosed. These systems are adapted
to simultaneously and independently vary temperature between
separate flow channels, preferably by employing separate,
individual heating elements in thermal communication with each of
four or more parallel flow reactors. The flow reactors are
preferably isolated from each other using a thermal isolation
system comprising fluid-based heat exchange. In preferred
embodiments, the axial heat flux can be fixedly or controllably
varied.
Inventors: |
Bergh; H. Sam; (San
Francisco, CA) ; Guan; Shenheng; (Palo Alto, CA)
; Engstrom; James R.; (Ithaca, NY) ; Hardt;
Steffen; (Mainz, DE) ; Lohf; Astrid;
(Karlsrahe, DE) ; Michel; Frank; (Bad Mergentheim,
DE) |
Correspondence
Address: |
SYMYX TECHNOLOGIES INC;LEGAL DEPARTMENT
3100 CENTRAL EXPRESS
SANTA CLARA
CA
95051
US
|
Assignee: |
Symyx Technologies, Inc.
Santa Clara
CA
|
Family ID: |
26788677 |
Appl. No.: |
11/448349 |
Filed: |
June 6, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10094257 |
Mar 7, 2002 |
|
|
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11448349 |
Jun 6, 2006 |
|
|
|
60274065 |
Mar 7, 2001 |
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Current U.S.
Class: |
422/600 ;
422/198 |
Current CPC
Class: |
B01L 2300/0861 20130101;
C40B 40/18 20130101; B01J 2219/00747 20130101; B01J 2219/00835
20130101; B01J 2219/00587 20130101; B01J 2219/00873 20130101; B01L
7/00 20130101; B01L 2300/1883 20130101; B01J 2219/00308 20130101;
B01J 2219/00689 20130101; B01J 2219/00707 20130101; B01L 3/5027
20130101; C40B 60/14 20130101; B01J 2219/0086 20130101; B01J
2219/00745 20130101; C40B 30/08 20130101; B01J 2219/0095 20130101;
B01J 19/0093 20130101; B01J 2219/00698 20130101; B01L 2300/18
20130101; B01J 2219/00961 20130101; B01J 2219/00788 20130101; B01J
2219/0072 20130101; B01L 7/54 20130101; B01J 2219/00495 20130101;
B01J 2219/00869 20130101; B01J 19/0046 20130101; B01J 2219/0081
20130101; B01J 2219/00286 20130101; Y10T 436/2575 20150115 |
Class at
Publication: |
422/196 ;
422/198 |
International
Class: |
B01J 8/04 20060101
B01J008/04; B01J 19/00 20060101 B01J019/00; B01J 10/00 20060101
B01J010/00 |
Claims
1. A parallel flow reaction system for effecting four or more
simultaneous reactions in four or more reaction channels, the
reaction system comprising four or more reactors configured and
arranged in an array with a center-to-center distance between
adjacent reactors of not more than about 10 times the diameter of
the reactor for reactors with circular cross-sections, or not more
than about 10 times the length of a chord intersecting the center
of the reactor for reactors having a non-circular cross-section,
each of the four or more reactors comprising a surface defining a
reaction cavity for carrying out a chemical reaction, an inlet port
in fluid communication with the reaction cavity, and an outlet port
in fluid communication with the reaction cavity, the four or more
reactors being adapted for effecting a chemical reaction at
reaction temperatures of greater than about 100.degree. C., a fluid
distribution system for simultaneously supplying one or more
reactants to the reaction cavity of each of the four or more
reactors, and for discharging a reactor effluent from the outlet
port of each such reaction cavity to one or more effluent sinks,
and a temperature control system comprising four or more
individually-controllable heating elements in thermal communication
with the four or more reactors, respectively, for simultaneously
and individually controlling the temperature of each of the four or
more reactors, the temperature control system being adapted to
provide individually variable temperature differences of at least
about 10.degree. C. as compared between four or more spatially
adjacent reactors.
2. The reaction system of claim 1 wherein each of the four or more
heating elements provides an axially-varying heat flux to the
reaction cavity of its respective reactor.
3. A parallel flow reaction system for effecting four or more
simultaneous reactions in four or more reaction channels, the
reaction system comprising four or more reactors, each of the four
or more reactors comprising a surface defining a reaction cavity
for carrying out a chemical reaction, an inlet port in fluid
communication with the reaction cavity, and an outlet port in fluid
communication with the reaction cavity, the four or more reactors
being adapted for effecting a chemical reaction at reaction
temperatures of greater than about 100.degree. C., a fluid
distribution system for simultaneously supplying one or more
reactants to the reaction cavity of each of the four or more
reactors, and for discharging a reactor effluent from the outlet
port of each such reaction cavity to one or more effluent sinks,
and a temperature control system comprising four or more
individually-controllable heating elements in thermal communication
with the four or more reactors, respectively, for simultaneously
and individually controlling the temperature of each of the four or
more reactors, each of the four or more heating elements providing
an axially-varying heat flux to the reaction cavity of its
respective reactor.
4. The reaction system of claims 1 or 3 wherein the temperature
control system is adapted to provide individually variable
temperature differences of at least about 50.degree. C. as compared
between four or more spatially adjacent reactors.
5. The reaction system of claims 1 or 3 wherein the temperature
control system is adapted to provide individually variable
temperature differences of at least about 100.degree. C. as
compared between four or more spatially adjacent reactors.
6. The reaction system of claims 1 or 3 wherein the four or four or
more heating elements are resistive heating elements.
7. The reaction system of claims 1 or 3 wherein the volume of the
reaction cavity of the four or more reactors is not more than about
1 ml.
8. The reaction system of claims 1 or 3 wherein the four or more
reactors comprise an array of four or more reactors configured and
arranged such that the spatial density of reactors in a
two-dimensional array is not less than about 1 reactor/10 cm.sup.2,
or in a linear or curvilinear array is not less than about 1
reactor/3 cm.
9. The reaction system of claims 1 or 3 wherein the four or more
reactors are configured and arranged in an array having at least
one reactor that is about equidistant from at least three other
reactors.
10. The reaction system of claims 1 or 3 wherein the four or more
reactors each have a reaction cavity volume of not more than about
1 ml, the four or more reactors being configured and arranged in an
array having at least one reactor that is about equidistant from at
least three other reactors such that the spatial density of four or
more reactors in the array is not less than about 1 reactor/10
cm.sup.2, and the temperature control system is adapted to provide
individually variable temperature differences of at least about
50.degree. C. as compared between four or more spatially adjacent
reactors.
11. The reaction system of claim 10 wherein the four or more
reactors are configured and arranged such that the spatial density
of four or more reactors in the array is not less than about 1
reactor/1 cm.sup.2.
12. The reaction system of claims 1 or 3 wherein the four or more
reactors comprise elongated reaction vessels.
13. The reaction system of claims 1 or 3 wherein the four or more
reactors are elongated reaction vessels having a first end section
substantially adjacent the inlet port, a second end section
substantially adjacent the outlet port, and a midsection between
the first end section and the second end section, the midsection
including a portion of the reaction cavity adapted to contain a
catalyst and defining a reaction zone.
14. The reaction system of claims 2 or 3 wherein the heating
elements associated with the four or more reactors are adapted to
provide a substantially uniform temperature profile along the
direction of reactant flow through a reaction zone of the
reactors.
15. The reaction of claim 14 wherein the heating elements
associated with the four or more reactors are adapted to provide a
temperature profile that varies by less than about 5% through the
reaction zone of the reactors.
Description
[0001] This application is a divisional of U.S. application Ser.
No. 10/094,257 filed on Mar. 7, 2002, which claims priority to
co-owned, U.S. Ser. No. 60/274,065 entitled "Parallel Flow Reactor
Having Improved Thermal Control" filed Mar. 7, 2001 by Bergh et al.
both of which are incorporated herein by reference for all
purposes.
BACKGROUND OF INVENTION
[0002] The present invention generally relates to materials science
research, and specifically, to combinatorial (i.e., high
throughput) materials science research directed toward the
identification and/or optimization of new materials. The invention
particularly relates, in preferred embodiments, to apparatus and
methods for optimizing chemical reaction systems, such as chemical
reaction systems involving heterogeneous catalysts.
[0003] In recent years, significant efforts have been extended
toward developing parallel systems, such as parallel reactors, for
the purpose of screening different materials, such as heterogeneous
catalysts, for particular properties of interest, such as
catalysis. U.S. Pat. No. 5,985,356 to Schultz et al. discloses
synthesis and screening arrays of materials in parallel for
catalysis, and U.S. Pat. No. 6,063,633 to Willson discloses
parallel flow reactors, and parallel screening techniques (e.g.,
thermography, chromatography, etc.) for evaluating catalysis. A
substantial portion of such effort has, however, focussed on
apparatus and methods for evaluating compositional space of the
materials (e.g., heterogeneous catalysts) of interest, while only a
relatively small portion of such effort has been directed toward
apparatus and methods for evaluating other parameter spaces--in
addition to compositional space. More specifically for example, in
the context of heterogeneous catalysis research, only limited
attention has been focused on the development of apparatus and
methods for high-throughput, parallel optimization of important
parameters such as catalyst (or catalyst precursor) processing
conditions and reaction conditions.
[0004] A number of parallel flow reactors are known in the art. For
example, PCT application WO 98/07206 (Hoechst) discloses a parallel
flow reactor said to be useful for evaluating chemical reactions
using minaturized reactors. U.S. Pat. No. 6,149,882 to Guan et al.
discloses, among other facets, a parallel flow reactor for
screening of heterogeneous catalysts in which feed flow is
controlled using flow restrictors such as capillaries to obtain
substantially the same flow in each of the reaction channels. More
recently, WO 00/51720 (Symyx Technologies, Inc.) discloses a
parallel flow reactor design that addresses several significant
technical challenges, including flow distribution challenges for
parallel screening of catalysts in very large numbers. Other
references, including WO 97/32208 (Technology Licensing Co., Ltd.),
DE 19809477 (Schuth), WO 99/41005 (BASF) and DE 19806848 (BASF)
likewise disclose parallel flow reactor configurations. Various of
the aforementioned references contemplate control of the reaction
temperature in the parallel reactors, including for example,
applying a thermal gradient across a plurality of reactors to
investigate temperature effects on a reaction of interest.
Typically, thermal control is effected for all of the reaction
vessels, collectively, or for a subset of the reaction vessels as
modules or zones.
[0005] These and other reactor designs known in the art do not,
however, specifically address approaches or contemplate apparatus
for investigating and/or optimizing reaction
temperature--simultaneously and independently--in relatively
closely-packed, highly parallel reactors. As reactor dimensions
become reduced, and as the spatial density of reactors increases,
significant thermal cross-talk between reaction vessels can be a
substantial obstacle for achieving simultaneous and independent
temperature control in such reaction systems.
[0006] Hence, there remains a need in the art to overcome such
deficiencies, and to provide for parallel flow reactors having
robust temperature-control capabilities for systematically
investigating and/or optimizing chemical processes with respect to
temperature.
SUMMARY OF THE INVENTION
[0007] It is therefore an object of the present invention to
provide apparatus and methods for more efficient identification
and/or optimization of materials and/or temperature conditions in
chemical processing systems (e.g., chemical reaction systems),
where temperature can be independently significant with respect to
performance in the application of interest.
[0008] Briefly, therefore, the present invention is directed to
parallel (e.g., multi-channel) chemical processing systems, and
especially, chemical processing Microsystems. Although primarily
discussed and exemplified herein in the context of parallel
reactors, and especially parallel microreactors, it is to be
understood that the invention has applications in other chemical
processing systems (e.g., mixing systems, separation systems,
material-processing systems, etc.), some of which are discussed in
varying detail below.
[0009] The invention is directed, in one embodiment, to parallel
reaction systems having the capability to simultaneously and
independently vary temperature between separate channels. The
parallel flow reaction systems can generally include a reactor
module that comprises four or more parallel flow reactors having
separate and independent temperature control for each of the four
or more reactors. Preferably, the temperature control system is
adapted to provide individually variable temperature differences of
at least about 5.degree. C., preferably at least about 10.degree.
C. as compared between four or more spatially adjacent reactors.
Advantageously, in some embodiments, the thermal control system of
the reaction system is capable of providing even higher temperature
differences between spatially adjacent reactors--such as at least
about 20.degree. C., at least about 50.degree. C., at least about
100.degree. C., at least about 150.degree. C. or at least about
200.degree. C.
[0010] The chemical reaction system of the invention generally
comprises four or more reactors and a fluid distribution system.
Each of the reactors comprises a surface defining a reaction cavity
for carrying out a chemical reaction, an inlet port in fluid
communication with the reaction cavity, and an outlet port in fluid
communication with the reaction cavity. The reaction cavity has a
volume of not more than about 100 ml, preferably not more than
about 50 ml, 20 ml, or 10 ml, and in some applications, not more
than about 7 ml, 5 ml, 3 ml, 1 ml, 100 .mu.l, 10 .mu.l or 1 .mu.l.
The reaction volume can be the same or different for the four or
more reactors. The fluid distribution system can simultaneously
supply one or more reactants from one or more external reactant
sources to the inlet port of the reaction cavity for each of the
four or more reactors, and can discharge a reactor effluent from
the outlet port of each such reaction cavity to one or more
external effluent sinks. As such, the invention generally comprises
a four- (or more-) channel parallel flow reactor, preferably of
micro-scale (e.g, not more than about 1 ml, for purposes hereof).
The reaction system can further comprise a detection system,
integral or separate from the reaction system, for evaluating the
reactions, for example, by detecting one or more reaction products
or unreacted reactants in the effluent streams of the four or more
reactors.
[0011] Significantly, in a particularly preferred embodiment, the
temperature of each of the four or more reaction vessels is
simultaneously and independently controlled using
separately-controlled heating elements (e.g. resistive heating
elements such as coil heaters) around each of the four or more
reactors, while thermal isolation between the four or more reactors
is accomplished by fluid-based heat exchange with an external heat
sink. Preferably, the fluid heat exchange includes forced
convection of a fluid between isolated, individually-heated
reactors. The fluid is preferably a gas, although a liquid is
suitable for some embodiments. In particularly preferred
embodiments, the fluid-type heat exchanger includes at least one
heat-exchange fluid inlet (with fresh, typically colder fluid) in
the vicinity of the reaction zone of the reactors.
[0012] In preferred embodiments, the heat flux being applied to
each of the reactors has a spatial profile, preferably an axial
profile (taken along the length of the flow reactor, with the
direction of flow) that can be varied (fixedly varied, or
controllably varied). Preferably, the heat-flux provided by the
heating elements can be axially varied to achieve a substantially
uniform axial temperature profile. Specifically, the heating
elements can be configured and arranged to achieve an axial
temperature profile (for the operating temperatures of the
reactors, discussed below) that varies by less than about 10%,
preferably less than about 5%, more preferably less than about 3%
and most preferably less than about 1% over a dimension (e.g., the
length) of the reaction zone that corresponds to the axial flow
path of the reactants through the flow reactor. The
axially-variable heat-flux provided by the heating elements can
compensate for variations in the heat-flux in the reaction zone
(e.g., hotter regions near the center of the reaction zone or
generally, other hot-spots), as well as variations in the heat-flux
profile associated with the circulating heat-exchange fluid cooling
the reactors. In another embodiment, the heat flux can also be
varied spatially over the array (e.g., as compared between
different reactors), and to compensate for the varied locations of
the four or more reactors relative to other reactors and to the
external environment (e.g. reactors that are centered in the array
versus reactors near an external edge of the reactor module).
Hence, design and/or control of the heating elements for each of
the reactors can effect a substantially axially-uniform temperature
profile for each of the four or more reactors independently, and
without regard to the relative location within the array of
reactors.
[0013] The invention is particularly advantageous for reaction
systems having thermal management challenges--such as exist for
such reactor modules in which the four or more flow reactors are
close-packed--that is, in which the four or more reactors have a
spatial density, taken along one or more cross-sections of a
two-dimensional array, of not less than about 1 reactor/100
cm.sup.2, preferably not less than about 1 reactor/50 cm.sup.2,
more preferably not less than about 1 reactor/10 cm.sup.2, and, in
some applications, not less than about 1 reactor/cm.sup.2, not less
than about 2 reactors/cm.sup.2, not less than about 1
reactor/mm.sup.2. In alternative embodiments having a linear array
or curvilinear array of reactors, the spatial density, taken along
a centerline of the linear array or curvilinear array, can be not
less than about 1 reactor/10 cm, preferably not less than about 1
reactor/7.5 cm, more preferably not less than about 1 reactor/3 cm,
and, in some applications, not less than about 1 reactor/cm, not
less than about 2 reactors/cm, or not less than about 1 reactor/mm.
The close-packed nature of the reactors can also be characterized,
especially for reactors comprising elongated reaction vessels, with
respect to spacing of the reactors. In one embodiment, the
center-to-center distance between adjacent reactors, taken at a
cross-section substantially perpendicular to the direction of flow,
is preferably not more than about 10 times the diameter of the
reactor (for reactors with circular cross-sections), or more
generally, not more than about 10 times the length of a chord
intersecting the center of the reactor (for reactors having a
non-circular geometry (e.g., hexagon, octagon, etc.). Preferably in
such embodiment, the center-to-center distance between adjacent
reactors, taken at a cross-section substantially perpendicular to
the direction of flow, is preferably not more than about 7 times,
and more preferably not more than about 5 times the diameter (or
more generally, the length of a chord intersecting the center of
the reactor). The center-to-center distance between adjacent
reactors can preferably range from about 1.5 times to about 10
times, more preferably from about 2 times to about 7 times, and
most preferably from about 3 times to about 5 times the diameter
(or more generally, the length of a chord intersecting the center
of the reactor), and is especially preferably about 3 times or
about 4 times the diameter or related chord length. This is
particularly true for higher numbers of close-packed reactors
(e.g., having a spatial density of not less than about 1
reactor/100 cm.sup.2 (two-dimensional array) or not less than about
1 reactor/10 cm (linear array or curvilinear array), or
characterized by a center-to-center distance of not more than about
10 times the diameter (or more generally, the length of a chord
intersecting the center of the reactor), such as six or more
reactors, eight or more such reactors, twelve or more such
reactors, sixteen or more such reactors, or more (as described
below) and especially where at least one, and preferably two or
more of such higher numbers of reactors are spatially nested--that
is, are configured and arranged in a two-dimensional array (or
three-dimensional array) having at least one reactor that is about
equidistant from at least three other reactors, and is preferably
about equidistant from at least four other reactors. For example, a
spatially nested reactor can be arranged internally to peripheral
reactors (e.g., an outer ring of peripheral reactors), such that
each spatially nested reactor has at least three adjacent reactors,
each of which is preferably substantially the same distance from
the spatially nested reactor.
[0014] The invention is also directed to methods of using such
reaction systems, and generally, such chemical processing systems,
for example, for evaluating catalytic reactions at various process
temperatures in a parallel flow chemical reactor. The method of the
invention can comprise, in a preferred embodiment, simultaneously
feeding reactants to a set of four or more parallel reactors
through a fluid distribution system. Each of the four or more
reactors comprise a catalyst effective for catalyzing a reaction of
interest, with the catalyst being substantially the same or
different as compared between the four or more reactors. The
catalysts are simultaneously contacted with the reactants with in
each of the four or more reactors under reaction conditions
effective for the reaction of interest. The temperature is
preferably controlled to be greater than about 100.degree. C.
during the course of the reaction. Also, the temperature of the
reaction zone of the four or more reactors is independently and
controllably varied as compared between channels, such that during
the course of the reaction, temperature differences of at least
about 5.degree. C., preferably at least about 10.degree. C. are
effected as compared between four or more spatially adjacent
reactors. In some method embodiments, even higher temperature
differences can be run simultaneously between spatially adjacent
reactors--such as at least about 20.degree. C., at least about
50.degree. C., at least about 100.degree. C., at least about
150.degree. C. or at least about 200.degree. C. The temperature
control system can comprise four or more individually-controllable
heating elements in thermal communication with the four or more
reactors, respectively. In preferred embodiments, each of the four
or more reactors can be thermally isolated from each other during
the course of the reaction by forced-convection heat transfer from
the reactor to the heat-exchange fluid. In preferred embodiments,
the heat flux to each of the four or more reactors can be axially
varied, to afford substantial flexibility for independently
controlling the axial temperature profile for each of the four or
more reactors. For example, the method can include varying the
axial heat flux of each of the four or more reactors such that the
axial temperature profile is substantially uniform, and in some
embodiments, such that the axial temperature profile (for the
operating temperatures of the reactors, discussed below) varies by
less than about 10%, preferably less than about 5%, more preferably
less than about 3% and most preferably less than about 1% over a
dimension (e.g., the length) of the reaction zone that corresponds
to the axial flow path of the reactants through the flow reactor.
The catalytic performance of each of the reactions can be
determined by approaches and instruments known in the art, for
example, by monitoring the reaction (e.g., heat of reaction) or by
determining the composition of reaction products and/or unreacted
reactants (e.g., by infrared spectroscopy, gas chromatography,
liquid chromatoagraphy, etc.).
[0015] Although especially useful in connection with parallel flow
reactors, the temperature-control system disclosed in the
aformentioned patent application can have applications for control
of other types of reaction systems (e.g., batch reactors,
semi-continuous reactors) and/or in non-reaction chemical
processing systems such as catalyst pretreatment protocols (e.g.
calcining of heterogeneous catalysts) or material characterization
(e.g. catalyst characterization) where parallel, independent
temperature control is desirable, especially where high-temperature
contact with a flowing fluid is involved.
[0016] The inventions disclosed herein, as well as various
permutations and combinations thereof, can be advantageously and
flexibly employed in optimizing temperature and
temperature-dependent properties chemical systems of interest, and
especially for optimizing post-synthesis, pre-reaction
processing/treatment conditions and/or reaction systems for
potential heterogeneous catalysts for a particular reaction of
interest.
[0017] Other features, objects and advantages of the present
invention will be in part apparent to those skilled in art and in
part pointed out hereinafter. All references cited in the instant
specification are incorporated by reference for all purposes.
Moreover, as the patent and non-patent literature relating to the
subject matter disclosed and/or claimed herein is substantial, many
relevant references are available to a skilled artisan that will
provide further instruction with respect to such subject
matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIGS. 1A and 1B are schematic views of a four-channel
parallel flow reactor (FIG. 1A), with a detail of one of the
reaction vessels thereof (FIG. 1B).
[0019] FIG. 2A through 2C are cross-sectional or schematic views of
a twenty-four channel parallel flow reactor (FIG. 2A) illustrating
a preferred temperature control system of the invention, including
a schematic heat-exchange fluid flowpath (FIG. 2B) and a detail of
one half of one of the reaction vessels thereof (FIG. 2C).
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0020] The present invention is related to the following patents
and/or patent applications, each of which is hereby incorporated by
reference for all purposes, including for the purpose of
combination of various features disclosed in the various related
applications to various features disclosed herein, to the highest
extent practical, based on the knowledge in the art, and coupled
with the guidance of this application and the related applications:
(1) co-owned U.S. patent application Ser. No. 60/187,566 entitled
"Apparatus and Methods for Multi-Variable Optimization of Reaction
Systems and Other Chemical Processing Microsystems", filed Mar. 7,
2000 by Bergh et al., (2) co-owned U.S. patent application Ser. No.
60/229,984 entitled "Apparatus and Methods for Optimization of
Process Variables in Reaction Systems and Other Chemical Processing
Systems", filed Sep. 2, 2001 by Bergh et al; (3) co-owned U.S. Pat.
No. 6,149,882 to Guan et al. entitled "Parallel Fixed-Bed Reactor
and Fluid Contacting Apparatus and Method"; (4) co-owned,
co-pending U.S. patent application Ser. No. 09/518,794, entitled
"Chemical Processing Microsystems, Diffusion-Mixed Microreactors
and Methods for Preparing and Using Same", filed Mar. 3, 2000 by
Bergh et a.; (5) co-owned, co-pending U.S. Ser. No. 09/801,390
entitled "Parallel-Flow Process Optimization Reactor" filed Mar. 7,
2001 by Bergh et al.; (6) co-owned, co-pending U.S. Ser. No.
09/801,389 entitled "Parallel Flow Reactor Having Variable Feed
Composition" filed Mar. 7, 2001 by Bergh et al.; (7) co-owned,
co-pending U.S. Ser. No. 60/274,022 entitled "Gas Chromatograph
Injection Valve Having Microvalve Array" filed Mar. 7, 2001 by
Bergh et al.; and (8) co-owned, co-pending U.S. Ser. No. 09/801,430
entitled "Parallel Gas Chromatograph with Microdetector Array"
filed Mar. 7, 2001 by Srinivasan et al.; and (9) co-owned,
co-pending U.S. Ser. No. 09/901,858 entitled "Methods for Analysis
of Heterogeneous Catalysts in a Multi-Variable Screening Reactor"
filed Jul. 9, 2001 by Hagemeyer et al. Further reference to several
of these applications is made below, in the context of the present
invention.
[0021] In a preferred embodiment of the present invention, a
chemical processing system is a reaction system that comprises a
plurality of reactors, a fluid distribution system, a temperature
control system, and optionally, a detection system. Generally, the
fluid distribution system can comprise an inlet subsystem for
providing reactants to the reactors, and an outlet subsystem for
discharging effluents from the reactors. A feed-composition
subsystem--for providing different feed compositions to the
reactors can be included in the inlet subsystem. A
flow-partitioning subsystem--for providing different flow rates to
the reactors, and/or a pressure-partitioning subsystems--for
providing different pressures in the reactors, can be included as
part of the inlet subsystem and/or in the outlet subsystem. A feed
temperature control subsystem can also be included, for temperature
control of feed being supplied to the reactors. The temperature
control system and the reactors are described in further detail
below. The detection system can be a separate, stand-alone system,
or can be integral with the reaction system.
[0022] The temperature control system generally comprises four or
more individually-controllable heating elements, preferably
resistive heating elements, in thermal communication with four or
more reactors, respectively. A forced convection cooling system can
provide thermal isolation between the four or more reactors.
[0023] More specifically, the temperature of each of the four or
more reaction vessels is simultaneously and independently
controlled using separately-controlled heating elements. The
heating elements can be resistive heating elements such as
resistive coil heaters associated with each reactor, or resistive
band heaters associated with each reactor. Alternatively, other
types of heating elements can be employed, including for example,
fluid-based heat-transfer elements (e.g., molten salt bath)
associated with each reactor, or heating elements involving
irradiation with electromagnetic energy (e.g, localized infrared
radiation, visible radiation, microwave radiation, radio frequency
(RF) radiation, etc.), such as can be provided using fiber optics,
lasers, or other approaches. The heating elements are in thermal
communication, preferably via conduction (i.e., thermally
conductive communication) with the reactors. The heating elements
can be adapted to effect a reaction temperature (or generally,
chemical processing temperature) in the individual reactors at
temperatures greater than about 50.degree. C., preferably greater
than about 100.degree. C., more preferably greater than about
200.degree. C., and in some embodiments, more preferably greater
than about 300.degree. C. Hence the reaction temperature (or
generally, chemical processing temperature) effected by the
individually-controlled heating elements can range from about
50.degree. C. to about 1500.degree. C., preferably from about
100.degree. C. to about 1000.degree. C., and more preferably from
about 200.degree. C. to about 800.degree. C. In some embodiments,
depending on the particular chemical reaction or process of
interest, the heating elements can be adapted to effect a reaction
temperature (or generally, chemical processing temperature) in the
individual reactors ranging from about 300.degree. C. to about
600.degree. C. or from about 400.degree. C. to about 600.degree.
C.
[0024] Thermal isolation between the four or more reactors is
accomplished by fluid-based heat exchange with an external heat
sink. Preferably, the fluid heat exchange includes forced
convection of a fluid between isolated, individually-heated
reactors. The heat-exchange fluid can be a gas (e.g., air or an
inert gas with respect to the chemical reaction of interest,
typically such as nitrogen or argon) or can be a liquid.
Forced-convention heat-exchange using a gaseous heat-exchange fluid
is particularly preferred for some embodiments. For example, use of
gaseous heat-exchange fluid avoids the potential for phase change
of the heat-exchange fluid for higher-temperature operations
(although such phase change may be desirable in other embodiments).
Gaseous heat-exchange fluid is particularly advantageous with
respect to forced-convection isolation between close-packed
reactors, since gasses generally allow for the use of higher linear
velocities past the reactors (as compared to liquids), and since
gasses generally have lower thermal conductivities (as compared to
liquids), which both individually and cumulatively have a positive
overall effect on heat-transfer out of and away from the reactors,
while eliminating or at least significantly limiting the extent of
thermal cross-talk between adjacent reactors. Regardless of the
phase or specific type of heat-exchange fluid, the heat-exchange
fluid can have a relatively low thermal conductivity, and
preferably, a relatively high heat-transfer coefficient with the
reactor vessels. Heat transfer between the heat-exchange fluid and
each of the individual reactors can be enhanced or optimized using
techniques known in the art. For example, the reactors can be
fabricated from materials having relatively high thermal
conductivity. The external surface of the reactors can be
controlled (e.g., by materials selection or by application of one
or more coatings) to improve or optimize the heat-transfer
coefficent at the surface (e.g., by reducing the thickness of the
heat-transfer boundary layer at the surface of the reactor). Also,
ultrasonic or megasonic energy can be applied to the reactor to
improve the heat-transfer coefficient at the surface of the
reactor. As another example, the individual reactors can have an
external surface having a relatively high surface area (e.g.,
greater than the surface area of right-cylindrical vessel of the
same volume)--such as can be provided using fins integral with the
external surface of the reactor, or in thermally conductive
communication with the external surface of the reactor. The
forced-convection, fluid-based heat-exchanger can be used as the
sole means for thermal isolation between the individually-heated
reactors, or alternatively, such fluid-based heat exchanger can be
used in combination with solid-material insulation as a thermal
barrier between vessels. Hence, a thermal isolation subsystem of
the temperature control system can comprise or consist essentially
of the fluid-based heat exchanger (as described above and
throughout).
[0025] The flow path or flow configuration of the heat-exchange
fluid is not narrowly critical, and can be adapted to the
particular design objectives of interest. In general, the
heat-exchange fluid flow configuration can include one or more
fresh (e.g., typically relatively cold) fluid inlets substantially
in the vicinity of the hottest part of the reactor--typically the
center of the reaction zone (e.g., in the midsection of an
elongated tube type reactor as shown in FIGS. 1A and 1B)--to
provide for maximum temperature differential, and accordingly,
maximum thermal heat flux from the reaction zone to the
heat-exchange fluid. (See, for example, FIG. 2B and the discussion
thereof below). The fluid-based heat exchanger can also have
multiple zones, with independent heat-exchange fluid feeds
associated with each zone. For example, the fluid-based heat
exchanger can have a central zone (taken axially) that includes at
least a central portion (e.g., midsection) of the reaction zone of
the reactors and one or more end section zones (taken axially),
each having independent heat-exchange fluid supply. Particularly
preferred embodiments are described hereinafter. Other embodiments
are within the skill in the art.
[0026] More specifically, in one particularly preferred embodiment,
the four or more reactors are elongated reaction vessels having a
first end section substantially adjacent the inlet port, a second
end section substantially adjacent the outlet port, and a
midsection between the first end section and the second end
section, with the midsection including a portion of the reaction
cavity adapted to contain a catalyst and defining a reaction zone.
In this case, the forced-convection heat exchanger can comprise one
or more heat-exchange fluid inlets substantially in the vicinity of
the midsections of the reactors, such that fresh heat-exchange
fluid supplied through the heat-exchange fluid inlet can contact
the midsection of the reactors before substantial contact with the
first or second end sections thereof. Also, the temperature control
system for such reactors can include a forced-convection heat
exchanger that comprises at least three heat-exchange zones, each
of the zones having one or more independent heat-exchange fluid
inlets for supplying fresh heat-exchange fluid to its associated
zone. A central heat-exchange zone can be adapted to effect heat
transfer from the midsections of the reactors. A first end
heat-exchange zone can be adapted to effect heat transfer from the
first end sections of the reactors. A second end heat-exchange zone
can be adapted to effect heat transfer from the second end sections
of the reactors. Additional heat-exchange zones can also be
employed. The multiple heat-exchange zones can be isolated, or
alternatively, can also have fluid-communication between zones. For
example, in the aforedescribed embodiment, the central
heat-exchange zone can be in fluid communication with each of the
first end heat-exchange zone and the second end heat-exchange zone,
such that at least some of the heat-exchange fluid supplied to the
central heat-exchange zone can flow to the first end heat-exchange
zone and the second end heat-exchange zone after contacting the
midsections (near the reaction zones) of the reactors in the
central heat-exchange zone.
[0027] The thermal control system, comprising the four or more
individually-controllable heating elements and the forced
convection cooling system considered in combination, provides a
robust platform for simultaneous processing or evaluation of
materials at different temperatures--even where the reactors are
close-packed and/or spatially nested (i.e., configured and arranged
in a two-dimensional array having at least one reactor that is
about equidistant from at least three other reactors).
[0028] Such a thermal control system can be effective, for example,
to provide individually variable temperature differences between
spatially adjacent reactors (.DELTA.T.sub.adjacent) of at least
about such that during the course of the reaction, temperature
differences of at least about 5.degree. C., preferably at least
about 10.degree. C. as compared between four or more spatially
adjacent reactors, and in some embodiments, at least about
20.degree. C., at least about 50.degree. C., at least about
100.degree. C., at least about 150.degree. C. or at least about
200.degree. C. Advantageously, such temperature differences can be
achieved in arrays of four or more, and preferably higher numbers
of reactors as described elsewhere herein, where such reactors are
configured and arranged in a close-packed array (e.g., as described
above) and additionally or alternatively where such reactors are
configured and arranged in a spatially nested array (e.g., as
described above). In preferred embodiments, in which six or more
reactors each have a volume of less than about 1 ml and are
arranged in an array format, optionally a spatially nested-array
format, in either case having a spatial density of not less than
about 1 reactor/cm.sup.2, and in which the reaction temperature (or
generally, the chemical processing temperature) is controlled to
range from about 300.degree. C. to about 600.degree. C., the
individually variable temperature differences can be at least about
10.degree. C. as compared between four or more spatially adjacent
reactors, and in some embodiments, at least about 20.degree. C., at
least about 50.degree. C., at least about 100.degree. C.
[0029] In preferred embodiments of the thermal control system,
considered separately and in combination with the above-described
preferred embodiments, the heat flux being applied to each of the
reactors has an axial profile, where the axial direction is
considered to be taken along the length of the flow reactor (i.e.,
parallel to the direction of flow), such that the heat flux can be
spatially varied to achieve a desired temperature profile over a
dimension (e.g. length) of the reaction zone. The spatial variance
in the thermal flux profile can be fixedly varied (without the
opportunity for operator change once the reactor design is
fabricated), or alternatively, can be controllably varied (such
that an operator can operationally change axial profile from
experiment to experiment without redesign of the reactor, but
potentially with or without hardware configuration change to the
reactor). In one embodiment, for example, a coil-type resistive
heater can be employed as heating elements, with the number of
turns per linear distance varying along the axial dimension of the
reactor. In an alternative example, some portions of the heating
element could be separately controlled from other portions thereof
(e.g., with higher current through one portion of a resistive
heating element) so that the axial thermal flux can be controllably
varied. In other approaches, the heating elements could be coupled
with spatial variations in insulation, to provide the varied heat
flux. Other embodiments are within the skill in the art.
Advantageously, axial variation in heat flux can be effected,
according to methods known in the art, to provide a substantially
uniform axial temperature profile over a dimension of the reaction
zone. For example, the heat elements can be configured and arranged
to provide the capability to effect a variation in the axial heat
flux of each of the four or more reactors such that the axial
temperature profile is substantially uniform for each of the four
or more reactors, and in some embodiments, such that the axial
temperature profile (for the operating temperatures of the
reactors, discussed herein) varies by less than about 10%,
preferably less than about 5%, more preferably less than about 3%
and most preferably less than about 1% over a dimension (e.g., the
length) of the reaction zone that corresponds to the axial flow
path of the reactants through the flow reactor. As noted, such
variations compensate for variations in the heat-flux profile
associated with the chemical reaction in the reaction zone, or that
associated with the circulating heat-exchange fluid cooling the
reactors. The flexibility afforded by such embodiments can also
compensate for the varied locations of the four or more reactors
relative to other reactors and to the external environment (e.g.
centered reactors versus reactors near an external edge of the
reactor module). Hence, in a particularly preferred approach, the
heating elements for each of the reactors are configured and
arranged to controllably vary the axial heat flux, such that a
substantially axially-uniform temperature profile for each of the
four or more reactors can be achieved--independently of each other,
and at different temperatures with respect to each other (i.e., as
compared between reactors).
[0030] In operation, thermal control system of the invention, and
particularly, the four or more heating elements can be
independently and controllably varied--relative to other heating
elements--to provide for controllably varied temperature
differences between individual reactors of the array of reactors.
Such variation can be used to investigate and evaluate the effect
of reaction temperature (or generally, processing temperatures such
as pretreatment temperatures (e.g., calcining temperatures) for
heterogeneous catalysts such as mixed-metal oxide catalysts) for a
reaction of interest (e.g., using substantially the same catalyst
in each reactor). Alternatively, both temperature and one or more
additional factors affecting the reaction--e.g., catalyst
composition or process variables such as pressure, feed
composition, feed flowrate, space velocity, catalyst loading,
catalyst shape, catalyst pretreatment history, catalyst synthesis
protocols, etc., can be controllably varied (e.g., in the same set
of simultaneous experiments), as taught for example in the related
applications. As noted, other uses (e.g., generally, materials
evaluation, materials characterization, materials treatment) will
be apparent to those of skill in the art.
[0031] The invention also includes methods for evaluating catalytic
reactions or for evaluating one or more materials (e.g. catalysts),
or for evaluating process conditions (e.g. temperature) in a
parallel flow chemical processing system (e.g. parallel chemical
flow reactor). As described, for example, with respect to a
parallel flow reactor, reactants are provided to a set of four or
more parallel reactors through a fluid distribution system, such
that the reactants simultaneously contact a catalyst or catalyst
precursor (e.g., substantially the same catalyst or a different
catalyst as compared between reactors) under reaction conditions
effective for the reaction of interest. The flow rates (and
associated parameters such as space velocity) can be the same or
different as compared between reactors. The temperature of the
reaction zone is independently, and controllably varied between the
four or more reactors, preferably using the thermal control system
described herein, during the course of the reaction. The reaction
products and unreacted reactants (if any) are then simultaneously
discharged from the four or more reactors. The catalytic
performance (e.g., activity and/or selectivity or other figure of
merit) can be determined, for example, by monitoring the reaction
or by determining the composition of reaction products and/or
unreacted reactants.
[0032] In each of the aforementioned chemical reaction systems, the
four or more reactors can be of any suitable design, including for
example designs modeling or substantially modeling
continuous-stirred-tank reactors (CSTR's), fixed bed reactors,
fluidized bed reactors, plug-flow reactors, channel-type reactors,
etc. Designs modeling or substantially modeling fixed bed,
plug-flow and CSTR-type reactors are preferred. For example, in one
preferred embodiment, the four or more reactors can be elongated
reaction vessels having a first end section substantially adjacent
the inlet port, a second end section substantially adjacent the
outlet port, and a midsection between the first end section and the
second end section. The midsection includes a portion of the
reaction cavity that is adapted to contain a catalyst (e.g., using
frits). The catalyst-containing portion of the reactors generally
defines the reaction zone. The aforementioned co-pending patent
applications of Guan et al. (filed Jun. 9, 1998) and of Bergh et
al. (U.S. Ser. No. 09/518,794) include preferred reactor and
reactor configuration designs. The reactor types in a particular
chemical reaction system can be identical to each other,
substantially the same as each other, or varied (e.g., for
optimization of reactor-type) in a particular chemical reaction
system. Moreover, the four or more reactors of the reaction system
are preferably structurally integrated with each other. As one
example, structurally integral reactors can be formed in a common
reactor block--either a uniform body or a plurality of laminates.
As another example, structurally integral reactors can include a
common support structure (e.g., can be joined substantially
adjacent at least one of their inlet section, outlet section and/or
central section by a common support member). Structural integration
between the four or more reactors can also be provided by the
forced-convection fluid-heat exchanger of the thermal control
system. The reaction system can alternatively comprise, however,
four or more structurally separate reactors. In either case, the
thermal control system is preferably an integral system--having
structural and/or control features that are common to each of the
four or more reactors (e.g., common forced-convection heat-exchange
system or common control software or common microprocessor).
[0033] Each of the aforementioned chemical reaction systems (or
processing/treatment systems) is preferably a microsystem, in which
the volume of the reaction cavity is not more than about 1 ml. In
some embodiments, the reaction cavities can have a volume of not
more than about 100 .mu.l, not more than about 10 .mu.l, or not
more than about 1 .mu.l. The smaller volume reaction systems are
particularly advantageous, for example, with respect to heat
transfer characteristics, as well as handling and interchanging of
modular components (e.g., arrays of diverse materials,
flow-restrictor modules, reactor modules, etc.).
[0034] The plurality of reactors are two or more reactors,
preferably four or more reactors, and more preferably nine or more
reactors. Higher numbers of reactors, including sixteen,
twentyfour, forty-eight or ninety-six or more reactors are
contemplated. When an array of microreactors is used in connection
with the invention, the number of reactors can be hundreds or
thousands. Additional general features of the reactors together
with preferred number of reactors, reactor types, types of
candidate materials optionally included within the reactors
(especially catalyst candidate materials), variations in
composition of the candidate materials (especially variations in
catalysts and/or catalyst precursors) loading/unloading of
candidate materials into/from the reactors, configurations of
arrays of reactors, planar densities of reactors, specific reactor
designs, and reactor fabrication approaches are as described in the
aforementioned co-pending U.S. patent applications of Guan et al.
(U.S. Pat. No. 6,149,882) and Bergh et al. (U.S. Ser. No.
09/518,794), collectively referred to hereinafter as the "Guan et
al. and Bergh et al. applications." Such additional general
features are hereby specifically incorporated by reference.
[0035] The format of the array of reactors is not narrowly
critical, and can generally include both spatially nested and not
spatially nested arrangements, of varying spatial densities.
Preferred configurations include spatially nested arrangements of
four or more reactors, preferably six or more reactors (or higher
numbers, as described elsewhere herein) having the spatial
densities as described above (see, for example, the Summary of the
Invention), and additionally or alternatively, preferably having
the reactor volumes described herein. Generally, the array of
reactors is configured to have at least one spatially nested
reactor--that is, at least one reactor that is substantially
equidistant from each of at least three other reactors, preferably
from each of at least four other reactors, and most preferably from
each of at least five other reactors.
[0036] Particularly preferred embodiments of the invention will now
be described with reference to the several figures.
[0037] With reference to FIG. 1A, an integrated chemical reaction
system 10 can comprise a tube-type flow-through reactor design
(e.g, analogous to a plug-flow reactor). The reaction system 10 can
comprise a plurality of microreactors 600. Each of the reactors 600
can comprise, with reference to FIG. 1B, an elongated reaction
vessel 70 such as a tube or channel. The elongated reaction vessel
70 can be independent of other structure or can be integrated with
and formed at, on or in a substrate (e.g., a plurality of laminae
or a unitary body). The elongated reaction vessel 70 is preferably
a stainless steel, ceramic, or quartz tube, and without limitation,
preferably has a diameter ranging from about 1 mm to about 20 mm,
more preferably from about 2 mm to about 10 mm, and most preferably
from about 4 mm to about 8 mm. The elongated reaction vessel 70 can
be lined with a liner 72 that is inert with respect to the reaction
and reaction conditions being evaluated. The liner 72 can be, for
example, a glass liner. The liner 72 can be separable from the
elongated vessel 70, or integral therewith--such as a lining
deposited as a coating on the inner surface of the elongated vessel
70. Typical coating materials include, for example, silica,
tungsten, tungsten carbide, titanium and titanium nitride, among
others. A candidate material (e.g., catalyst or catalyst precursor
material) 74 can be provided to and situated in the elongated
reaction vessel 70 in any suitable form--for catalysts as bulk
catalyst or as supported catalysts--and in either case in various
forms known in the art (e.g., pellets, beads, particulates,
microspheres, substantially uniform microspheres, etc). Particle
diameters are not narrowly critical, but can typically range from
about 1 .mu.m to about 1 mm, more typically from about 10 .mu.m to
about 500 .mu.m, and even more typically from about 50 .mu.m to
about 250 .mu.m. The candidate material 74 is preferably held in
position between porous end caps 126 (e.g., frits, screens, etc.)
situated on each of the reactor inlet port 71 and reactor outlet
port 73. Optionally, an inert filler 76, and preferably an inert
filler 76 having thermal insulating properties can also be provided
and situated between the porous end caps 126 and the candidate
material 74. Preferably, the inert, thermally insulating filler 76
can be sufficient to maintain the end sections (as shown, generally
adjacent to the inlet port 71 and outlet port 73) at a temperature
of less than about 200.degree. C. (to facilitate the use of
lower-temperature seal materials), and hence, to provide for a
temperature difference ranging from at least about 100.degree. C.
to at least about 400.degree. C. between the reaction zone (e.g.
containing candidate catalyst material 74) and the reactor inlet
port 71 (or reactor outlet port 72). The reactors 600 can be
fabricated and/or operated using manual, semi-automated or
automated instruments (e.g., robotic handling instruments) to
provide the candidate materials 74 and/or other components of the
reactor 600. The reactors 600 shown in FIGS. 1A and 1B can have a
low thermal mass, and can thereby provide for relatively fast
thermal cycling for processing/treatment of the candidate materials
(e.g., for calcining of catalysts or catalyst precursors) and for
establishing and/or varying reaction conditions in the reactors
600.
[0038] Referring again to FIG. 1A, the material-containing reactors
600 are formed as an array 100 of reactors 600, with each reactor
600 supported near the reactor inlet port 71 and the reactor outlet
port 73 by a first and second support plates 954, 955. As shown,
the plurality of reactors 600 are heated by temperature control
blocks--shown as heaters 980--adjacent to the material-containing
portion of the reactors 600 and in thermal communication therewith.
As such, the center, material-containing region of the reaction
system 10 can be a relatively "hot zone" region, while the inlet
and outlet-containing regions can be relatively "cold zone"
regions. The temperature can be varied between reaction vessels
600, and temperature variations (e.g., gradients) can also, as
desired, be established with multiple temperature zones along a
single reactor 600 and/or along the material-containing portion of
a single reactor 600. Seals, and preferably releasable seals
between the fluid distribution system and the reactors 600 can be
provided and integrated into the support plates 954, 955.
Advantageously, such a design allows for the fluid-distribution
seals to be located in the cold zones--and outside of the hot-zone,
thereby providing for greater flexibility with respect to sealing
materials, etc. Exemplary sealing materials include graphite,
fluoropolymer, metal seals, or other seal materials. Reactants 20
can be provided to the reactors 600 through an inlet distribution
subsystem 500 in fluid communication with the microreactors 600.
The inlet distribution subsystem 500 can comprise a first set 510
of inlet flow restrictors, and optionally, a feed-composition
varying subsystems (not shown in FIG. 1A). After contacting the
candidate materials (e.g., catalysts) 74 under the variably
controlled reaction conditions, reactor effluents 60 are passed
through an outlet (discharge) distribution subsystem 501, and
further to an external distribution (waste) system. The outlet
distribution subsystem 501 can comprise a second set 520 of outlet
flow restrictors. The inlet and outlet distribution subsystems 500,
501 can be thermally isolated from the microreactors 600 (e.g., by
air or other insulating gas, by temperature control block, etc.)
Evaluation of the candidate materials can be determined by analysis
of reaction products, for example, by sampling of the reactor
effluent streams as described above and/or in connection with the
Guan et al. and Bergh et al. applications. The chemical reaction
system can optionally be contained within a heated environment
(e.g, an oven 750, and in operation, a heated oven)--particularly
when liquid reagents are employed--to provide for additional
thermal energy to keep the feed stream and effluent streams in the
vapor phase.
[0039] In a preferred embodiment, the invention is exemplified by a
twenty-four channel, parallel-flow reaction system for effecting
twenty-four simultaneous reactions. Each of the twenty-four
reactors can be a fixed-bed type flow reactor, allowing for
evaluation of candidate catalysts under varied process conditions.
The reactor can also include a temperature-control subsystem for
controlling, individually, the temperature of each of the
twenty-four reactors.
[0040] The reactor module 4600, shown as a cut-away schematic in
FIG. 2A, comprises a 4.times.6 array of twenty-four reactor tubes
4610 individually supported in a reactor frame 4605. Each tube has
a reaction volume of about 1 ml. Each of the reactor tubes 4610 can
be individually heated using resistive coil heaters 4620 (e.g.
Watlow Mini-K-ring). Thermal isolation between reactor tubes 4610
is achieved using fluid-type heat exchanger to cool the
inter-reactor volume within the reactor frame 4610. FIG. 2B shows a
general schematic flow diagram for the heat-exchange fluid flowpath
through the array of reactors 4610. Referring to both FIGS. 2A and
2B, preferably, the cooling medium is air or inert gas, and is fed
into the reactor module 4600 substantially at the midsection
thereof--adjacent the central portion of the reaction zone of the
reactors 4610, in a first, primary central heat-exchange zone. The
heat-exchange medium contacts each of the reactors substantially at
its center, then generally splits and flows towards each end of the
reactors (4612, 4614). Plate cooling fluid (e.g. air) is also fed
through the top member 4606 and bottom member 4607 of the reactor
frame 4605, specifically through heat-exchange channels 4608 formed
therein, in a set of secondary, end heat-exchange zones.
Advantageously, as described in greater detail above, and with
reference to FIG. 2C, the heat flux associated with the resistive
coil heaters 4620 can be axially varied to account for heat
variations due to the reaction, and to balance heat removal by the
cooling media such that a substantially axial uniform temperature
profile is obtained. FIG. 2C shows a detail of one half of the
resistive coil heaters 4620, with axial variation in the number of
winds of the resistive heating wire. The wire connection 4630
allows for individual, controlled heat input for each of the
reactors. The feed gas flows into the reactor tube inlet 4612, and
optionally contacts a catalyst (e.g., supported in the reactor tube
using frits (not shown)) under reaction conditions to effect the
chemical reaction of interest. The reaction products and unreacted
reactants are discharged through the reactor tube outlet 4614.
[0041] Although described particularly in connection with gas and
liquid phase chemical reaction systems, the present invention has,
as noted above, applications in other areas, including for example,
as a parallel adsorbent system, extraction system and/or
solubilization systems for research and development in, for
example, the gas processing fields, environmental applications or
in pharmaceutical manufacturing. The chemical processing systems
described herein can also be employed, for example, in connection
with solid-state chemistry and solid-state material research and
development. In any of the aforementioned applications, evaluation
of candidate materials and/or of processing conditions can be
effected by characterizing one or more properties of the plurality
of candidate materials (e.g., crystal structure) after processing
in the chemical processing system.
[0042] In light of the detailed description of the invention and
the examples presented above, it can be appreciated that the
several objects of the invention are achieved.
[0043] The explanations and illustrations presented herein are
intended to acquaint others skilled in the art with the invention,
its principles, and its practical application. Those skilled in the
art may adapt and apply the invention in its numerous forms, as may
be best suited to the requirements of a particular use.
Accordingly, the specific embodiments of the present invention as
set forth are not intended as being exhaustive or limiting of the
invention.
* * * * *