Parallel flow reactor having improved thermal control

#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.

#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.

#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.

#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).

#FIGS. 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).

#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 al.; (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.

#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.

#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.