Multi-stage multi-tube shell-and-tube reactor

1 MULTI-STAGE MULTI-TUBE SHELL-AND-TUBE REACTOR

FIELD OF THE INVENTION

The present invention relates to shell-and-tube catalytic reactors having improved heating or cooling capabilities for use With exothermic or endothermic chemical reactions.

BACKGROUND OF THE INVENTION

Generally, a shell-and-tube catalytic reactor is a type of reactor Which is used to efliciently remove reaction heat. In some uses of these reactors, a catalyst is filled in a plurality of reaction tubes; a reaction fluid (gas and/or liquid) into the reaction tubes to cause a chemical reaction for obtaining a desired product; and a heat transfer medium is circulated through the reactor shell such that the chemical reaction can occur under controlled thermal conditions. Shell and tube reactors typically include a number of reaction tubes held in place in the shell by one or more tubesheets; shell nozzles are used for introducing and WithdraWing the heat transfer medium; tube nozzles are used for introduction of reactants into the reaction tubes and for WithdraWing product therefrom; and appropriate dividers and/or baffles are used to separate the respective reactor parts for their specific functions. The reactor parts are typically made from materials that do not react With the materials being processed in the reactor.

In some cases, during the use of shell-and-tube catalytic reactors, hot spots can occur at a local point in one or more of the reaction tubes. These hot spots can cause problems, such as the deterioration of the catalyst, leading to a reduction in catalyst life, and/or a decrease in the production of the desired product. Thus, methods for efliciently transferring heat to or from the reaction tubes in the shell-and-tube reactor is a desirable goal.

Prior Art:

The folloWing prior art documents are hereby incorporated herein by reference in their entirety.

U.S. Pat. No. 3,566,961 is entitled “tubular reactor for carrying out endothermic and exothermic reactions With forced circulation.” As set forth in the abstract, this patent teaches a tubular reactor With forced circulation of a heat transfer medium Which flushes the outside of the reaction tubes in axial direction, the heat transfer medium being supplied to, and WithdraWn from, the reactor Wall uniformly through circular pipelines, and particularly the constructional shape of deflecting guide plate means arranged transversely to the direction of floW and having annular openings around the reaction tubes for uniform floW toWards all the tubes of the nest of tubes.

U.S. Pat. No. 3,792,980 is entitled “reactor for carrying out reactions accompanied by a change in heat.”As set forth in the abstract, this patent teaches a shell and tube reactor for reactions accompanied by a change in heat. Reaction material floWs through the tubes and a heat exchange medium floW through the shell to remove or supply heat of the reaction. Also a pump disposed in the reactor on the shell side circulates the heat exchange medium Within the shell. The tubes are disposed in spaced sectors so that passageWays are provided for the circulating heat exchange medium. Heat exchange medium is WithdraWn and supplied to the shell and is itself subjected to heat exchange outside the reactor. Improved distribution of the heat exchange medium Within the shell is obtained by WithdraWing and supplying the heat exchange medium, respectively, from and to the aforesaid passageWays.

2

U.S. Pat. No. 4,101,287 is entitled “combined heat exchanger reactor.” As set forth in the abstract, this patent teaches a one-piece, integral, high strength, combined heat exchanger-reactor comprising a monolithic honeycomb structure Wherein the channels thereof are divided into tWo or more groups; group one carrying one fluid and group tWo carrying another fluid Which differs from the first in composition and/or temperature and/ or pressure and/or direction of floW, the main design feature of the combined heat exchangerreactor (CHER) being that group one channels extend outWard parallel to the channel axis and perpendicular to the cross-section of the honeycomb and each channel of this group one being in thermal contact through common Walls With channels of group tWo While each channel of group one is separated from other channels of group one by the intervening voids formed by the presence of the channels of group tWo. The extended ends of the channels of group one extending from one or both ends of the honeycomb are manifolded at one or both ends so as to form a separation of the entrances and/or exits of the extended group one channels from the recessed group tWo channels thereby permitting the entry and/or exit of fluid in group one channels While preventing entry of the same fluid into the group tWo channels thereby permitting the independent passage of different fluids through the different channel one and channel tWo systems, the common Wall Which exists betWeen channels of the different groups alloWing heat conduction from the fluid in one group of channels to the fluid in the other group of channels. In this manner, very precise concentration and/ or temperature control may be maintained over the fluids and/or catalysts Which exist in the different channel groups, enabling one to perform complex reactions, either self-induced or catalytic, in the reactor With greatly enhanced yields and/or selectively due to the refined temperature and/or concentration control Which is made possible by the present invention.

U.S. Pat. No. 4,929,798 is entitled “pseudoadiabatic reactor for exothermal catalytic conversions.” As set forth in the abstract, this patent teaches a multitubular catalytic reactor for exothermal catalytic reactions comprises a bundle of parallel tubes all of the same length and a catalyst Within the tubes. The tube bundle has an inlet side and an outlet side. Devices are provided for introducing separately reactants to Within the tubes of the reactor and coolant to the channels defined betWeen adjacent tubes of the bundle. The coolant is introduced into the channels co-currently With the direction of floW of the reactants. The products are WithdraWn from the tubes independently of the coolant. The reactor is particularly adapted to a single stage conversion of methanol into gasoline boiling point range constituents using crystalline aluminosilicate catalysts.

U. S. Pat. No. 5,027,891 is entitled “method for transferring heat betWeen process liquor streams.” As set forth in the abstract, this patent teaches a method of transferring heat betWeen process liquor streams such as streams of caustic liquor in the Bayer process for producing alumina from bauxite, utilizing a heat pipe arrangement for heat exchange. The process streams respectively pass in contact With one surface of a first heat-exchange Wall and one surface of a second heat-exchange Wall While being isolated from the second surfaces of the tWo Walls; these second Walls are exposed to a closed volume (also isolated from both process streams) containing a heat transfer fluid that vaporizes beloW the temperature of the hotter process stream and condenses above the temperature of the cooler process stream. The heat transfer fluid vaporizes at the exposed surface of the Wall contacted by the hotter stream, and condenses at the exposed surface of the