Tube bundle reactor for catalytic gas phase reactions, automatically bypasses recirculated heating medium in cold, viscous state, during start up

摘要

During reactor (2) start up, heat exchange medium bypass (22) throughput, corresponds with a comparatively-cold and viscous state. In this case, the reactor vessel (8) is partially bypassed. During steady-state reactor operation, flow is automatically controlled as a function of the instantaneous heating power required in the reactor. In this case, heat exchange medium passes through the reactor at an essentially constant flow rate. Preferred Features: Control functions are carried out in a common unit. Bypassing is controlled on temperature and ranges of bypass ratio are specified for start-up and running conditions. Annular channels and openings form inlets and outlets for the heat exchange medium. A heater (30) is provided for the medium, and is used during start up. It is in e.g. a valved, auxiliary circuit in a location unrelated to the main medium inlet and outlet. An external heating medium is employed in a heater. Further details of the bypass, its valving and circulating pump (12) connections and disposition are provided. A mixer may be included. Conventional thermal expansion and de-gasification provisions are made. An additional pump mitigates against cavitation in the circulation pump. The design is further detailed.