US2537472A

US2537472A - Apparatus for carrying out an exothermic reaction at substantially constant temperature

Info

Publication number: US2537472A
Application number: US635385A
Authority: US
Inventors: Massiot Louis
Original assignee: Compagnie Francaise de Raffinage SA
Current assignee: Compagnie Francaise de Raffinage SA
Priority date: 1944-08-16
Filing date: 1945-12-15
Publication date: 1951-01-09
Anticipated expiration: 1968-01-09

Description

Jan. 9, 1951 MASSIOT 2,537,472

APPARATUS FOR CARRYING OUT AN EXOTHERMIC REACTION AT SUBSTANTIALLY CONSTANT TEMPERATURE Filed Dec. 15, 1945 4 Sheets-Sheet 1 Fig.7;

INVENTOR LOUIS Masseot r ATTORNEYS Jan. 9, 1951 L. MASSIOT 2,537,472

APPARATUS FOR CARRYING OUT AN EXOTHERMIC REACTION AT SUBSTANTIALLY CONSTANT TEMPERATURE Filed Dec. 15, 1945 4 Sheets-Sheet 2 Jan. 9, 1951 MASSIOT 72,537,472

APPARATUS FOR CARRYING OUT AN EXOTHERMIC REACTION AT SUBSTANTIALLY CONSTANT TEMPERATURE I Filed Dec. 15, 1945 4 Sheets-Sheet a INVENTOR L ozus Masszo 29 @QU MT ATTORNEYS Jan. 9, 1951 MASSIOT 2,537,472

APPARATUS FOR- CARRYING OUT AN EXOTHERMIC REACTION AT SUBSTANTIALLY CONSTANT TEMPERATURE Filed Dec. 15, 1945 4 Sheets-Sheet 4 INVENTORY Loaz/s Massz/ot ATTORNEYS iatented Jan. 9, 1951 UNITED TENT oFFlcE APPARATUS FOR CARRYING OUT ANlIXO- THERMIO REACTION AT SUBSTANTIALLY CONSTANT TEMPERATURE Louis Massiot, Paris, France, assignor to Compagnie Francaise de Rai'iinage (Societe Anonyme), Paris, France, a company of the French Republic Application December 15, 1945, Serial No. 635,385 In France August 16, 1944 Section 1", Public Law 690, August 8, 1946 Patent expires August 16, 1964 6 Claims It is well known that exothermic reactions between gaseous fluids and liquids have been regulated heretofore according to methods and with means of various kinds among which it is possible to mention continuous operation in a boiler provided with stirring means and reaction in a column provided with surface contact means or with plates.

increasing the size of the apparatus used if the time of contact between the reacting materials is critical. This is the case for instance of chlorination when it is desired to avoid the production of super-chlorinated products. It is true thatit is known to wash the gases produced by the product to be chlorinated but this is only a safety step and does not permit control of the operation.

- A first object of the present invention consists in providing under rational and practical conditions for the regulating of exothermic reactions between gases and liquids.

V In conformity with the invention the column, wherein the gases which have passed through the reaction chamber are washed, is used as a means for controlling the temperature.

I Y This complementary part to be thus played by the washing column allows not only the exothermic reaction to be regulated, but also the size of this washing column to be reduced.

If in fact the hot zone of this regulating and washing column reaches the upper portion therewith thermostats which provide an automatic ,adjustment of the feed or of the temperature of reaction.

A second object of the invention consists in facilitating a reaction in a column substantially filled-with a body of a reaction liquid. The use ;of such an apparatus is known and is suitable for laboratory purposes. On a largerscale, the

liquid-filled column presents certain diificulties from the point of view of transfer of heat. If a tubular reactor is used, there arises a difliculty in uniformly distributing the gas throughout the cross-section of the reactor. Moreover in the presence of chlorine and hydrochloric acid or of any corrosive medium of the same kind, the parts of the apparatus in contact with the bath reacting materials should be coated with lead.

Such a lead coating is very diiiicult to apply inside tubes having a substantial length.

Applicant has eliminated these dilliculties by providing cooling unit consisting of an outer tube having a closed end containing a vaporizable liquid and an inner tube within the outer tube for conducting the vaporizable liquid to the closed end of the outer tube. These cooling units a are hereinafter referred to as cooling plugs. The heat absorbed from the reacting material produces inside the cooling plugs the boiling and evaporation of a suitable thermostatic liquid. Such plugs act therefore like vaporising tubes.

Certain characteristic features of the invention are illustrated in Figs. 1 and 2 of accompanying drawings which show respectively:

In Fig. 1, a diagram showing the application of the invention to the chlorination of a liquid such as gas oil.

In Fig. 2, a perspective view of the upper end of a cooling and vaporising plug. 7

In Figs. 3 to 5, further details of the apparatus.

Reverting to Fig. l, the exothermic reaction in the example of chlorination of gas oil is executed in a cylindrical chamber 1. The chlorine admitted through a pipe 2 at the lower end of n this chamber is injected therein through a number of porous plates 3 of which only one has been illustrated. The gas thus subdivided passes through the liquid 4 and produces by reacting with the latter an evolution of heat. The reaction should be executed at constant temperature,

'say C. or thereabouts, and the heat is removed by a certain number of cooling plugs 5 of which only one has been illustrated in Fig. 1.

The heat absorbed produces inside the plug the boiling and vaporising of a thermostatic liquid such as toluene 5. The vapors produced are condensed in a reflux condenser shown diagrammatically at l.

Ihe condensed liquid and the liquid carried along by the gases fall back on an upper annular plate 8 and pass through openings 9 (Fig. 1) into zontal axis whi h 3 central tubes II] which lead them back to the base of each of the plugs 5.

This transfer of liquid carried by the annular plate 8 towards the inside ofthe tube it! forms one of the characteristic features of the invention.

A particular form of execution of this transfer is shown in Fig. 2.

The transfer is executed by means of a series of V-shaped overflow weirs II, the number of which is three for instance, welded at 129 from one another, between the vaporising pipe and the central collecting tube l0. These. overflow weirs serve also as stays providing a rigid connection between the outer pipe 5 and the inner pipe In.

The central collecting tubes preferably and with deflectors I: which return downwardly the major part of the liquid carried along duringwaporising.

The upper annular plate 8, the lower plate l4 carrying the porous plates 3 and the plugs 5 are prefera l ma e o ea'i ma ed tea T plu s 5 are removable an a e secu ed o the. p e nn Pla 8]; t y re hel by s ay plates not sho n- The hydrochloric vapors and the chlorine passins out o he eact on c am r l P through the duct into the small regulating column i6 inside which they are washed with gas oil entering from I] and passing through the duct 18 intothe reaction chamber l.

Thermometers l9 located at various heights and of which two only have been illustrated, allow" the control at each moment of the level of the hot'zone. "I'h'ese thermometers may without departing" from the scope of the present invention be replaced by thermostats acting on a cock or'valve controlling the admission ofgas oil at ll: or that ofchlorine, or else said thermostats may regulate the condensation by regulatingflow of the cooling fluid.

The chlorinated gas oil is removed through the duct'iil'while thehydrochloric vapors are, removed at. 21. from the small regulating and washing, column.

The. foregoing description relates to. apparatus for carryingout exothermic. reactions between a liquid-1 and a, gas. Essentially the. same. apparatus. may. be. used, for. carrying out reactions in.- volving solid catalysts.

o. aci tate. i troduction f: the cataly t, the apparatus m unted to. tch about. a b ri- Permits the arrarai o, be ro ked titer. it ha be n. i q en vted, Ai a he osi iqncqltresrq dina anormal .2- ea r is. r es,

The ata st mas s, l c d. i es sta e. bewee he. q qli lug nd the'body he p'ar atuss'o. astoforirf a singlelayr throughout the lieight'of the apparatus orelse a plurality of e" s bymeansv ofintermediary' grates if it is I edto avoid layers having too'great a height.

The; supporting gratesv may play the part of dampers or baffle plates forimproving the contacting conditions between the fluid and the catalystl It issuificient to this end to provide ierforations throughout. onlyv part. of said grates.

Fig. 3,, which corresponds to Fig. 1, with the same conventional simplification, showsthe rockmg, axis 2. and thecatal t 3; h ape on h grates 24.

v he cki o he appara usmay be undesirble n he e se i. a brittle. ca al st, Ap ican a Wa e s. iseas 1 des ning. al ew n the apparatus to be filled in its operative position, while retaining the possibility of rocking for emptying the exhausted catalyst.

This modification is illustrated in Fig, 4.

The reaction chamber essentially comprises a tubular member, cylindrical or not, 25, closed at its lower end by a plate 26 and at its upper end by a removable cover 21. The plate 26 is provided with openings in which it carries a series.

ofplugs 28 closed at their upper ends 29 and open at their lower ends into a chamber 30. These plugs contain inner concentric tubes 31 opening through their upper end 32 inside the corresponding plug and secured at their lower end in openings in a plate 33 so as to communicate on the lower side of the latter with a chamber 34 connected through a pipe 35 with a reservoir 36. This reservoir, the diameter of which is smaller than that of the reaction chamber, contains at its upper end a water circulating condenser 31 and at its lower end a heat generating apparatus 38, illustrated diagrammatically each in the form of a co i l A thermostat 39 acts on the output of a pump to the duty ofwhich is to recycle the thermostatic liquid through the pipes 4 l and 42. The catalytic space is bounded by the bodyor tubular member 25 the plate 26, the cover 21 and the plugs 28. The catalyst is heaped inside said space a nd forms either a single layeror else if necessary a plurality of layers on intermediary grates 43'. The reacting vapors or liquids enter the catalytic chamber through the pipe 44 and pass out of the same through the duct 45. lihe reaction heat vaporises part of the thermostatic liquid contained in the plugs. This production of vapors produces a more or lessintense circulation by reason of the airlift or sweeping phenomenon. The suspension thus produced is collected; at 3-2- by the tubes 3 land is-led to the reservoir 38 wherein the vapor produced is condensed on the worm 31-: this condensatetogether' with he liquid phase of the suspension falls back and is drawn into the pump Anion recycling-purposes. The rate of evaporationand: consequently the intensity of superheating depends on the height of liquid in vaporising plugs 23; by varying: the rate t which pump an withdrawsliduidfromthe res ervoir 3-6, it is possible to modifyat willthesup ply ofliquid and therefore the height thereof inside the plugs 28. If necessary, it is possible to produce inside said plugs a forced circulation of the thermostatic liquids.

It is possible to provide for a preliminary heating of the reacting fluid withoutany extra expense by using the reaction heat. It issufiicient to thisend to provide at the upper end; of the chamber a zone a, with or withoutcatalyst in the vertical passage of which the plugs 28; are qr 29%?) pr d 'h n r er transverse (Fig, 5). The re ac ting fluids enter cold at 44; and are heat-edthrough contact with the plugs 28-; wh ile the thermostaticfluid cools or condenses inside said zone. The height of' the zone A is designed in a manner suc-h th-at the productto be treated may be brought to a suitable temperature when it has reached the zone B or cataly sing zone For starting, the apparatus being cold, itis necessary to first bring the catalytic mass; to reaction temperature. To this end, the by-pass ll84 l is first opened and, the pump 40" being stopped;the thermostatic liquid is-caused' to; boil through the aetion of the heat generating means 38: the vapors producedfollow-a path opposed-to that described hereinabove and: are; lediby the tubes-3+ tothe upper end'ofthaplug -28 -and condensed inside said plugs. The'condensate returns to the possibilities *of heating for starting the exothermic reaction remains applicable to any reaction requiring a continuous input of heat. In this case, the heat required by the reaction is produced, not only for the starting but also throughout the duration of the reaction by the generator 38.

The arrangement described provides therefor the following advantages.

(it) It allows the execution of either endothermic or exothermic reactions;

(b) It allows the use as a catalytic chamber of the inter-tubular space as, by reason of the absence of any upper tube sheet the loading and unloading of the catalyst may be executed through any means known per se such as rocking, removal of the supporting grates etc.

(o) .It allows heaping the catalyst throughout a height as considerable as may be desired by reason of the presence of the intermediary supporting grates; for a predetermined catalytic volume, the diameter may be reduced, which is importantffor apparatuses operating under pressure.

(d) Itp-rovides for the maintenance of a more nearly uniform temperature by reason of the use of the vaporising, condensation or forced circulation of a given fluid. V

(e) Itallows an adjustment of the heat transfer rate and therefor to a certain extent of the reaction temperature in a particularly simple manner consisting in the adjustment of the speed of circulation of the cooling or heating fluid.

(f) It allows recovering in situ whenever desired the reaction heat with a view to the prelimiriary heating of the charge.

(g) The mounting of the apparatus is made in a particularly easy manner by reason of the omission of the upper tube sheet; the tubes are free and may extend without any impairment of the solidity of the apparatus.

(h) By reason of the simplified construction of the apparatus, it is possible without any difliculty to use the thermostatic fluid under a high pressure. The same thermostatic liquid may be suitable throughout a comparatively wide range of temperature by making its pressure vary inside the chamber by control of flow of water inside the condenser 31. This pressure will be adjusted advantageously by acting on the throughput of water by means of a manostat 58 through the agency of an automatic valve 49.

According to another further characteristic feature of the invention, the small column l-B serving for washing the gases and for regulating the reaction, may also serve for introducing the catalyst into the reacting medium.

When the catalyst used is not soluble or is difficult to dissolve in the reacting substances and if for instance it is desired to proceed with a chlorination in presence of ferric chloride, diniculties will be met with when it is attempted to distribute in a homogeneous manner the catalyst in the hydrocarbon to be chlorinated.

It will be then advantageous to provide the small column l6 with iron shavings or turnings. Whereas iron is not attacked by hydrochloric acid in an anhydrous medium, it be noted that there forms in the presence of hydrocarbons and of the small amounts of chlorine passing into the column, a compound substance which is carried along by the product to be'chlorinated inside the reaction chamber.

It is moreover possible to adjust the introduction of the catalyst by using two small columns of which one will serve for regulating and washing purposes, while the other serves for the introduction of the catalyst and is alone filled with iron shavings. Only a fraction of the products passing out of the reaction chamber is caused to pass through the latter small column so as to limit, if required, the attack on the iron shavings.

What I claim is:

1. Apparatus for carrying out an exothermic reaction at substantially constant temperature comprising in combination, a vertical elongated casing; a partition dividing said casing into a reaction chamber adapted to contain a reaction mixture and a relatively small condensing chamber near the top of'said casing; at least one pair of concentric tubes mounted in said casing, communicating at one of their ends with said condensing chamber, and extending downwardly through said partition into said reaction chamher; the outer of said tubes having a closed lower end within said reaction chamber and cooperating with theinner tube to define an annular space I adapted to contain a cooling liquid in heat exchange relation with said reaction mixture within said reaction chamber, whereby the heat of reaction of said reaction mixture vaporizes said cooling liquid to cause vapors thereof to pass through said annular space into said condensing chamber, a refrigerated condensing unit mounted in said condensing chamber to condense vapors of said cooling liquid entering said condensing chamber, and at least one conduit interconnecting the exterior of said outer tube and the interior of said inner tube for conducting condensed cooling liquid from said condensing chamber to said inner tube and thence to the bottom Of said outer tube within said reaction chamber.

2. Apparatus according to claim 1 and wherein said condensing unit is aligned with said inner tube and the upperend of said inner tube is flared outwardly beyond the periphery of said outer tube to collect condensate dropping from said condensing unit and prevent it from entering said annular space.

3. Apparatus according to claim 1 and wherein said conduit consists of a pair of members exto permit rocking of said casing about a horizontal axis.

6. Apparatus according to claim 1 and wherein said reaction chamber is provided with a series of vertically spaced grates for supporting layers of catalysts.

LOUIS MASSIOT.

' (References on following page) REFERENCES GlTEf) UNITED STATES PATENTS Number Name Date Askenasy et a1. Nov. 14, 1905 Brooks et a1. June 26, 1917 Hechenbleikner Jan. 1'7, 1933 Number 8 N m D e Oxley et a1, Dec. 15., .1936 Brill et a1. Feb. 27, 1940 Houdry Apr. 2, 1940 Wilson et a1. Oct. 22, 1940 Hammond Aug. 29, 1944 Hulsberg F ,Dec. 18, 1945 Hull et a1 July 2, 1946 Certificate of Correction Patent No. 2,537,472 January 9,1951 LOUIS MASSIOT It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 26, after the word chlorine insert if present; column 4:, line 36, for airlift or sweeping read airlift or sweeping;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 26th day of June, A. D. 1951.

THOMAS F. MURPHY,

Assistant Gammissz'oner of Patents.