Multiple Automated Reactor Systems (MARS). 1. A Novel Reactor System for Detailed Testing of Gas-Phase Heterogeneous Oxidation Catalysts

Abstract

An automated reactor system for a detailed performance evaluation of gas-phase heterogeneous oxidation catalysts that utilizes a parallel array of six fixed microreactors called the Multiple Automated Reactor System, or MARS, is described. The key MARS components include a gas manifold that safely generates a light hydrocarbon oxidation feed composition, an array of six fixed-bed microreactors with dedicated components for control of individual reactor feed gas flow rates and temperatures, an integrated gas sampling and gas chromatography system for online analysis of feed and product gas compositions, and a process automation control package based on process logic controller technology. The addition of one or more liquid feed components, such as steam or organometallic catalyst surface modification agents, is also possible through a dedicated liquid feed vaporizer subsystem. The automation package contains all of the elements needed for logging of process sensors, monitoring of all process alarms, control of all process variables, interlock sequencing, and communication between the operator and automation hardware through a human−machine interface. These features allow a user-defined catalyst testing protocol to be downloaded from the automation so that the system can safely operate 24/7 in an unattended mode. Two versions of the MARS are described that mainly differ in the fixed-bed microreactor configuration and the length of the heated zones used for transport of product gases from the catalytic zone to the online gas sampling system. One version employs a classical U-tube fixed-bed microreactor, whereas the second version uses a straight-through fixed bed. An overview of key operating characteristics is provided. It is shown in part 2 of this series of papers that the contribution of metal-wall-catalyzed and homogeneous gas-phase reactions on the observed hydrocarbon and oxygen conversions can achieve significant yet different levels in each reactor configuration for 1,3-butadiene oxidation. The need to first assess the role of undesired reactions and then to either eliminate or minimize their contribution to the desired solid-catalyzed reaction in parallel microreactors is emphasized.

Transient Behavior and Stability in Miniaturized Multiphase Packed Bed Reactors

“…High-throughput catalyst testing has gained increasing popularity, not only for stage I testing (testing qualitatively many new catalyst formulations) but also for stage II (measuring quantitatively performance, kinetics, and deactivation). − The reactors used are significantly smaller than the conventional packed beds, and design rules and operating procedures for these smaller-scale systems are very limited. In this paper we address one important aspect of operation: the transient behavior.…”

Integrated Microreactor System for Gas-Phase Catalytic Reactions. 3. Microreactor System Design and System Automation

“…Overall Process Configuration. The automated, integrated microreactor system (AIMS) was designed to be functionally equivalent to a heterogeneous gas-phase catalyst testing system with parallel reactors, such as the multiple automated reactor system or MARS . The key system components of the AIMS are shown in Figure .…”

“…The automated, integrated microreactor system (AIMS) was designed to be functionally equivalent to a heterogeneous gas-phase catalyst testing system with parallel reactors, such as the multiple automated reactor system or MARS. 38 The key system components of the AIMS are shown in Figure 1. These components include the following: (i) a feed gas manifold, which consists of pressure regulators and a bank of mass flow controllers (MFCs) for online generation of the reaction feed gas mixture; (ii) a reactor manifold, which consists of dedicated MFCs that meter the feed gas mixture to individual parallel-operating microreactors; and (iii) an online reactor feed and product gas analysis system.…”

Integrated Microreactor System for Gas-Phase Catalytic Reactions. 1. Scale-up Microreactor Design and Fabrication

“…It was also surmised that demonstration of these capabilities could also provide new knowledge needed for other emerging applications where microreactor systems could have an impact, such as those involving synthesis of novel nanomaterials, biotechnology, alternate energy processes, pharmaceutical discovery and manufacture, and specialty chemicals. For these reasons, the emphasis here was placed on demonstrating the operability of a prototype microelectromechanical system (MEMS) from first principles that had the same functionalities that are present in a more conventional laboratory-scale system versus developing a new automated microreactor system for studying gas-phase solid-catalyzed reactions . This work addresses the key challenges in microreactor systems design, packaging, integration, automation, and handling of process hazards.…”

“…For these reasons, the emphasis here was placed on demonstrating the operability of a prototype microelectromechanical system (MEMS) from first principles that had the same functionalities that are present in a more conventional laboratory-scale system versus developing a new automated microreactor system for studying gas-phase solidcatalyzed reactions. 60 This work addresses the key challenges in microreactor systems design, packaging, integration, automation, and handling of process hazards. Incorporation of various sensors and devices for process monitoring using a high degree of process automation and control is also achieved to demonstrate safe operation of potentially explosive reaction mixtures involving hydrocarbons or NH 3 and O 2 .…”