Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Including heat exchanger for reaction chamber or reactants...
Reexamination Certificate
1999-11-08
2004-01-13
Tran, Hien (Department: 1764)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Including heat exchanger for reaction chamber or reactants...
C422S198000, C422S198000, C422S198000, C422S200000, C422S211000
Reexamination Certificate
active
06676906
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a reactor for carrying out reactions having a high enthalpy change containing catalyst particles between cooled dividing walls in at least one reactor vessel.
BACKGROUND OF THE INVENTION
Such a reactor is known from the journal Hydrocarbon Processing, March 1991, page 134. This is a multitube reactor with catalyst particles in the tubes. The tubes are cooled on the jacket side of the reactor by means of boiling water or other suitable heat-transfer media.
The distribution of the reaction space and the catalyst particles over a plurality of tubes ensures that in the case of an operating fault any self-accelerating reaction caused by local overheating is restricted to one reaction tube and does not encompass the entire reactor. This reactor construction has proven itself but has a number of disadvantages.
The reactor wall has to be designed for the coolant pressure, which in practice is often at a high pressure. As a result, the reactor wall is very thick and therefore expensive, difficult to transport and assembly on the construction site is ruled out.
For large diameters, the tube plates are very thick and therefore expensive and prone to damage by thermal stresses.
A great deal of effort is required to weld the many reaction tubes into the thick tube plates.
Filling the many reaction tubes requires a great deal of effort and care. In particulars care must be taken to ensure that the tubes are filled uniformly with the same pressure drop in the various tubes so that a reaction tube through which too little reaction mixture passes because of the high pressure drop is not overheated.
Owing to the high weight, carbon steel is usually used for the reactor, although this makes rust unavoidable. However, rust acts as a catalyst poison for many reactions. For this reason, the reactor has to be sandblasted when the catalyst is removed, and this sandblasting is costly because of the large number of reaction tubes.
Only upright reactors are possible.
The cooling area per catalyst volume can be chosen only within narrow limits.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to achieve a simpler reactor construction combined with a high level of safety in the case of faults during operation and avoidance of the abovementioned disadvantages.
According to the invention, this object is achieved by a reactor for carrying out reactions having a high enthalpy change containing catalyst particles between cooled dividing walls in at least one reactor vessel, characterized in that the cooled dividing walls are formed by means of metal plates/metallic components and hollow or intermediate spaces in the form of channels for accommodating and conveying a cooling medium.
According to the invention, this object is achieved by a reactor for carrying out reactions having a high enthalpy change containing catalyst particles between cooled dividing walls in at least one reactor vessel, characterized in that the cooled dividing walls are formed by means of metal plates/metallic components and hollow or intermediate spaces in the form of channels for accommodating and conveying a cooling medium.
The separate reaction chambers produced by the cooled dividing walls also prevent overheating of adjacent reaction chambers in the event of the abovementioned operating malfunctions. Metal plates/metallic components which can be used according to the invention are commercially available as coolable or heatable panels and make inexpensive solutions for the internal reactor fittings possible.
In an advantageous embodiment of the reactor of the invention, a plurality of metal plates are assembled, preferably vertically, with a spacing between them to give a metal plate pack and thus form a free space into which the catalyst particles are poured. Tube plates are dispensed with and the reaction chambers between the plates are filled like a fixed bed without cooling. This is a substantial improvement over a reactor according to the prior art.
The metal plate packs are advantageously made up of flat, preferably parallel, plates or of cylindrically curved, preferably concentric, plates. Such plates, including plate packs, are commercially available at a relatively low cost.
In a preferred embodiment of the reactor of the invention, a plurality of metal plate packs are arranged next to one another in the reactor vessel in such a way that they form a module of plate packs in which the feed gas flows in parallel through the plate packs. This can be realized easily, particularly also in horizontal vessels. As a result, the limits of constructability are shifted to significantly larger units and low pressure drops are made possible when using the reactor of the invention.
It is also possible for the feed gas to flow through a plurality of modules either in the same reactor vessel, preferably above one another, or in a plurality of reactor vessels, parallel or in series. Combined with the choice between upright and horizontal reactor vessels, the reactor can thus be optimally matched to the available space and the permissible pressure drop in the reactor.
Further advantages of the reactor of the invention result from the combined effect of the features of the invention with those of its advantageous embodiments:
The reactor wall has to be designed only for the pressure of the reaction gas and, for example, not for the higher pressure of the steam which is generated during cooling by vaporizing boiler feed water.
The reactor requires no tube plates and is therefore significantly lighter than a reactor according to the prior art. In addition, the metal plates can be constructed of stainless steel so that the abovementioned problems when using carbon steel do not occur.
The cooling area per catalyst volume can be freely chosen within very wide limits.
Owing to the fact that the reactors of the invention are significantly lighter for the same throughput, transport, installation and foundations are cheaper than in the case of reactors according to the prior art.
Constructability limits and safety considerations do not restrict the production capacity which can be installed at a given location.
In an advantageous use of the reactor of the invention, a highly exothermic catalytic reaction is carried out between the cooled dividing walls of the reactor.
The reactor can be used, for example, in the reaction of acetylene to form ethylene. In this use, the reactor of the invention makes it possible to simplify the process as explained below and at the same time to make the cooled reactor simpler, safer and cheaper and to shift its constructability limits significantly in the direction of larger units.
When using the reactor of the invention, the reaction chambers in the reactor are bounded by cooled dividing walls and cooling is effected by a fluid which flows within the dividing walls in a very simple manner as a result of, according to the invention, the cooled dividing walls in the reactor being made up of metal plates and hollow spaces in the form of channels being provided in the metal plates to accommodate and convey at least one fluid.
The dividing walls form separate reaction chambers for the reaction of acetylene to give ethylene. Should an over-reaction actually occur in one of these reaction chambers, the over-reaction remains restricted to this small space and does not encompass the entire reactor. This very significantly increases production safety and makes it acceptable for the first time to construct reactor units which are significantly larger than those possible according to the prior art.
Since surfaces made of metal plates are cheap to produce, it is possible to make available additional heat-exchange area without incurring high costs. In particular, inert material can be used instead of catalyst at the gas outlet from the reactor, so that although a reaction no longer takes place at this point of the reactor, cooling still takes place by means of the metal plates. This ensures that no hot gas from an over-reaction heats the product gas stream and can l
Heisel Michael
Millen White Zelano & Branigan P.C.
Tran Hien
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