Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Including heat exchanger for reaction chamber or reactants...
Patent
1995-07-18
1999-03-30
Tran, Hien
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Including heat exchanger for reaction chamber or reactants...
422188, 422189, 564 67, B01J 804
Patent
active
058884602
DESCRIPTION:
BRIEF SUMMARY
FIELD OF APPLICATION
In a general aspect, the present invention relates to a reactor for two-phase reactions, in particular for urea synthesis at high pressure and temperature of the type comprising: mutually spaced relationship in said shell, and said perforated plates.
The present invention also relates to in-situ modernization of reactors for two-phase reactions, in particular for urea synthesis at high pressure and temperature.
In the description given below and in the following claims, the term: "in-situ" modernization, is understood to mean the on-site modification of a pre-existing reactor in order to improve its performance and obtain e.g. greater production capacity and/or greater conversion yield and/or reduction in energy consumption.
In the terminology of the field this type of modernization is also termed "retrofitting" or "revamping".
In the field of two-phase reactions at high pressure and temperature, e.g. for urea synthesis or hydrolysis, the requirement for increasing the conversion yield of synthesis reactors to improve their production capacity and reduce energy plant consumption in which said reactors operate is increasingly felt.
PRIOR ART
In order to satisfy said requirement synthesis reactors comprising a vertical tubular shell in which is supported a plurality of superimposed horizontal perforated plates in mutually spaced relationship have been becoming increasingly used.
The reaction product, e.g. urea, is obtained by placing in intimate contact a liquid phase and a gaseous phase comprising ammonia and carbon dioxide (CO.sub.2) flowing in the shell from below upward.
The perforated plates have the function of mixing together said phases to facilitate their intimate contact and hence exchange of mass and heat indispensable for conversion of the reagents, ammonia and CO.sub.2, into urea.
Synthesis reactors for two-phase reactions in accordance with the prior art are mainly of two types depending on the perforated plates used.
A first type of reactor as shown in FIG. 1 comprises a plurality of superimposed perforated plates extending horizontally over the entire cross section of the reactor and in which is defined a plurality of holes for the passing of a two-phase gas and liquid flow.
Since the liquid and gaseous phases pass through the same holes, there is alternating passing of gas and liquid with a pulsing flow which prevents intimate gas and liquid mixing. As a result there are low mass and heat transfer coefficients and hence low conversion yield.
In another case as shown in FIG. 3 the synthesis reactor comprises a plurality of superimposed horizontal perforated plates in mutually spaced relationship. Between the perimetric edge of each of these plates and the internal wall of the reactor is defined an annular aperture.
Even in this case however it is not possible to obtain the desired intimate mixing between the liquid phase and the gaseous phase because the liquid flows preferentially along said peripheral apertures while the gas tends to coalesce in the central part of the reactor.
Since they do not ensure effective intimate contact between the reagents the reactors in accordance with the prior art are not able to permit an optimal exchange of material and heat, which is the basic condition for achieving optimal conversion yield. Said reactors operate therefore far below their potential production capacity with resulting high energy consumption of the plant, e.g. for urea production, in which said reactors operate.
SUMMARY OF THE INVENTION
The technical problem underlying the present invention is to provide synthesis reactors capable of operating with high conversion yields so as to obtain greater production capacity and much lower energy consumption than those of the plants in accordance with the prior art mentioned above.
The above technical problem is solved in accordance with the present invention by a reactor of the above type, and characterized in that the openings for liquid flow defined in correspondence of at least two adjacent perforated plates are mutually
REFERENCES:
patent: 2848493 (1958-08-01), Dewling et al.
patent: 3922147 (1975-11-01), Sze et al.
patent: 4051206 (1977-09-01), Bunas et al.
patent: 4341640 (1982-07-01), Landis
patent: 4356132 (1982-10-01), Belyakov et al.
patent: 4539077 (1985-09-01), Jonckers et al.
patent: 5223238 (1993-06-01), Czuppon
Silva Paolo
Zardi Federico
Tran Hien
Urea Casale S.A.
LandOfFree
Reactor for two-phase reactions, in particular for urea synthesi does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reactor for two-phase reactions, in particular for urea synthesi, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reactor for two-phase reactions, in particular for urea synthesi will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1211357