OA12645A

OA12645A - Process for decomposing hydrogen peroxide under pressure and device for heating an equipment.

Info

Publication number: OA12645A
Application number: OA1200400021A
Authority: OA
Inventors: Benoit Requieme
Original assignee: Atofina
Priority date: 2001-07-27
Filing date: 2002-07-26
Publication date: 2006-06-16
Also published as: ATE322460T1; FR2827794B1; DE60210471D1; AP1943A; EP1414742B1; WO2003011751A1; EP1414742A1; AP2004002971A0; EA200400231A1; EA005700B1; FR2827794A1

Abstract

The invention concerns a method for decomposing hydrogen peroxide at high pressure, which consists in decomposing hydrogen peroxide at a pressure of at least 20 bars using a solid catalyst comprising at least an element selected among the group consisting of manganese, vanadium, palladium and their mixtures. The invention also concerns a device for heating an equipment, using said catalyst.

Description

012645 1

The présent invention relates to a process fordecomposing hydrogen peroxide at high pressure, inparticular in order to use the heat produced to heat anequipment, as well as a device for heating an equipment,such as an oil capital equipment.

It is known that the décomposition of hydrogenperoxide can be catalyzed at atmospheric pressure usingcertain transition metals such as iron, chromium, silver,platinum, etc.

Moreover, the article entitled "Hydrogen peroxideapplications for the oil industry" by Jack. H. Bayless,which appeared in the journal World Oil in May 2000,discloses the exploitation in the oil industry of theexothermic nature of the décomposition of hydrogen peroxidein the presence of a catalyst to produce heat in order toheat equipment. This article however does not giveinformation on the nature of the catalyst used. Neitherdoes it describe a device which in practice makes such ause of the décomposition of hydrogen peroxide possible.

However, for the application which is envisaged, thedécomposition reaction of hydrogen peroxide shouldgenerally be carried out under pressure and it has beennoted that the solid catalysts such as iron oxide, silverand platinum, in the form of a wire mesh are ineffectiveand/or rapidly deactivate at high pressure. Furthermore,the usual catalysts such as the soluble dérivatives ofCr111, Fe11 OR Fe111, generally used in liquid form, aredifficult to use in a process which opérâtes continuously. 012645 2

They should be injected separately from the hydrogenperoxide to avoid the décomposition of the hydrogenperoxide in the supply pipes and are very soon ineffectivebecause they are evacuated from the installation by theoxygen and/or the steam produced by the reaction.

Which are solid catalysts are therefore sought, evenat high pressures.

According to a first aspect, the aim of the inventionis a process allowing the décomposition of hydrogenperoxide under high pressure conditions, in particular atpressures higher than 20 bars. A subject of the invention is a process for thedécomposition of hydrogen peroxide at high pressure, inwhich hydrogen peroxide is decomposed at a pressure of atleast 20 bars using a solid catalyst comprising (as main active component) at least one element selected from the group consisting of manganèse, vanadium, palladium and their mixtures. According to one embodiment , the pressure is at least 80 bars.

According to one embodiment, the catalyst comprises manganèse and/or palladium.

According to one embodiment, the catalyst comprises partially oxidized manganèse.

According to one embodiment the catalyst is supportedon a material support, which is inert under the reactionconditions.

According to one embodiment, the catalyst is asupported catalyst based on palladium only or in a mixture 012645 3 with one or more éléments selected from platinum, gold andiridium.

According to one embodiment the hydrogen peroxide isin the form of an aqueous solution.

According to one embodiment, the aqueous solutioncontains less than 90% and preferably less than 70% byweight of hydrogen peroxide.

According to one embodiment, the solution isstabilized.

According to one embodiment, the process according tothe invention is useful for producing heat, oxygen and/orsteam.

According to a second aspect, an aim of the inventionis therefore to propose a device allowing the exploitationof the exothermic nature of the décomposition of hydrogenperoxide to heat equipment.

Therefore a subject of the invention is a process forheating an equipment, comprising - a chamber for the décomposition of a reagent • equipped with means for supplying the reagent, • containing a solid catalyst comprising at leastone element selected from the group consisting ofmanganèse, vanadium, palladium and their mixtures, and • having a form which is able to cooperate with thatof the equipment in order to heat it; and - means for évacuation of the products resulting fromthe décomposition.

According to one embodiment, it also comprises meansfor injection of a flushing fluid inside thedécomposition chamber. 012645 4

According to one embodiment, the interior wall of thedécomposition chamber is covered with a material which isrésistant to high températures.

According to one embodiment the catalyst comprisesmanganèse and/or palladium.

According to one embodiment, the device is used at apressure of at least 20 bars, advantageously at least 80bars.

Other characteristics and advantages of the inventionwill become apparent on reading the disclosure whichfollows and which is given with reference to the drawingsin which: - Figure 1 diagrammatically represents a firstembodiment of the device according to the invention, whichcan be used to eliminate deposits of hydrates of gas or ofparaffins in a pipe for the transport of hydrocarbons; - Figure 2 diagrammatically represents a secondembodiment of the device according to the invention, whichcan be used to eliminate deposits of hydrates of gas or ofparaffins in a subsea well head for the production ofhydrocarbons; - Figure 3 represents the change in température as afunction of time, during the high pressure décomposition ofhydrogen peroxide with different quantifies of supportedpalladium catalyst; - Figure 4 represents the change in température as afunction of time, during the high pressure décomposition ofhydrogen peroxide with a supported palladium catalyst andunder different pressures; 012645 - Figure 5 represents the change in température as afunction of time, during the high pressure décomposition ofhydrogen peroxide with a supported palladium catalyst andreleasing the pressure at the end of the reaction; 5 - Figure 6 represents the change in température as a function of time, during the high pressure décomposition ofhydrogen peroxide with a supported palladium catalyst andwith successive recycling of the catalyst;

Figure 7 represents the change in température as a10 function of time, during the high pressure décomposition ofhydrogen peroxide with a manganèse catalyst, then with a recycled manganèse catalyst;

Figure 8 represents the change in température as afunction of time, during the high pressure décomposition of 15 hydrogen peroxide with a mass catalyst based on previously(partially) oxidized manganèse, under different pressuresand with hydrogen peroxide solutions of differentconcentrations;

Figure 9 represents the change in température as a 20 function of time, during the high pressure décomposition ofhydrogen peroxide with a new or recycled mass catalyst ofvanadium, under different pressures and with hydrogenperoxide solutions of different concentrations.

25 DETAILEP DISCLOSURE OF THE INVENTION

Process according to the invention

In the process according to the invention, a reagent which is hydrogen peroxide is decomposed at a pressure of 30 at least 20 bars using a solid catalyst comprising at leastone element selected from the group consisting of 012645 6 manganèse, vanadium, palladium and their mixtures. Theseéléments form the main active constituent of the catalyst,which can commonly comprise other éléments.

This décomposition can be exploited to generate heat,oxygen and/or steam under high pressure conditions.

As preferred catalysts, the catalysts containingpalladium and/or manganèse are used.

The catalyst can be in powder form. However in theenvisaged application, in order to avoid increasing theloss of charge associated with passing the hydrogenperoxide through the catalyst and to facilitate theévacuation of reaction products, it is préférable to use acatalyst in which the particle size is greater than 0.1 mm,preferably between 0.5 mm and 50 mm and more particularlybetween 1 mm and 10 mm.

The catalyst can also be supported on a materialsupport, which is inert under the reaction conditions,which is well known to the person skilled in the art andwhich can be, for example, alumina, silica, analuminosilicate, a zeolite or a metallic structure. Thissupport may in the form of a bail, pellet or extrudate. Amaterial employed as a packing or as a static mixer canalso advantageously be used.

Preferably, this support is principally constituted byaluminium oxide, silica or a mixture of the two.

The catalyst content of the support is then generallycomprised between 0.1% and 10%, preferably between 0.5% and5%, relative to the total mass of the support.

The supported or unsupported catalyst, can be preparedaccording to any process known to the person skilled in the art. 012645 7

The hydrogen peroxide is generally in the form of anaqueous solution.

Preferably, the aqueous solution contains less than90% and, in particular, less than 70% by weight of hydrogenperoxide, relative to the total weight of the solution.

The aqueous solution generally contains stabilizers,such as, for example those based on pyrophosphate,phosphate and tin dérivative, and/or based on dérivativesof phosphonic acids. Such solutions are known.

The process according to the invention is effective athigh pressures, which is surprising if it is consideredthat the standard catalysts used at atmospheric pressure(in particular iron oxide) are totally ineffective atpressures of 20 bars. The process according to theinvention opens new routes under high pressures, which hâvenever been explored until now.

The process is also effective at pressures greaterthan for example 80 bars, or even greater than 160 bars.

Device according to the invention

The device according to the invention can be used, inparticular to eliminate deposits of hydrates of gas orparaffins in equipment for drilling, producing ortransport ing hydrocarbons, by the production of heat bydécomposition of a reagent such as hydrogen peroxide orhydrazine, preferably hydrogen peroxide.

It is within the scope of this application that thedevice according to the invention will now be describedwith reference to attached Figures 1 and 2, but it goeswithout saying that the description which follows can besuitable for other applications. 012645 8

Figure 1 diagrammatically représente a firstembodiment of the device according to the invention whichcomprises a chamber 1 for décomposition of a reagent whichcan be mounted so as to be in contact with a pipe 2 fortransporting a mixture of liquid and gaseous hydrocarbons.

This décomposition chamber 1 generally has interiorwalls covered with a material which is résistant to hightempératures. It contains a solid catalyst 3 comprising atleast one element selected from the group constituted bymanganèse, vanadium, palladium and their mixtures.

Preferably, a solid catalyst 3 which comprisespalladium and/or manganèse is chosen.

The device also comprises means for supplying areagent, such as hydrogen peroxide, which comprise aréservoir 4 for the reagent 5 connected by a pipe 6 to thedécomposition chamber 1 through a valve 7 with adjustableopening and a non-return valve 8.

In order to eliminate the deposits of hydrates of gasor of paraffins présent on the interior wall of the pipe 2,the valve 7 is progressively opened, so as to injectreagent into the décomposition chamber 1.

On contact with the catalyst 3, the reagent décomposésproducing a large quantity of heat which is transmitted bythe décomposition chamber 1 to the pipe 2 and heats themixture of hydrocarbons which circulâtes in this pipe 2,via the wall of the latter.

In turn, the hydrocarbons heat and dissolve thedeposits of hydrates of gas or of paraffins downstream ofthe section of pipe on which the décomposition chamber 1 ismounted. 012645 9

The quantity of heat provided to the hydrocarbons incirculation is controlled by action on the opening of thevalve 7 for a shorter or longer period of time.

The products of the décomposition of the reagentcannot return to the réservoir 4 due to the non-returnvalve 8 at the inlet and they are partially evacuated bythe outlet pipe 11 through the outlet non-return valve 12.

The device according to the invention also comprisesmeans for injecting a flushing fluid such as nitrogen inorder to eliminate the products of the décomposition of thereagent in the décomposition chamber 1.

These means for injecting a flushing fluid comprise aréservoir 13 for the storage of nitrogen under pressureconnected to the pipe 6 downstream of the valve 7 by a pipe15 through an inlet valve 14 for the nitrogen withadjustable opening.

After an injection of reagent into the décompositionchamber 1, the valve 7 is closed and the inlet valve 14 forthe nitrogen is open, in order to produce a flow ofnitrogen inside the chamber 1 which carries away theresidual products of the décomposition of the reagent.

The device according to the invention can optionallyalso comprise means for injecting a liquid additive inorder to facilitate or accelerate the décompositionreaction of the reagent. These means for injecting a liquidadditive are particularly useful when the device accordingto the invention is used under high hydrostatic pressure,in order to start the décomposition reaction.

When the reagent is hydrogen peroxide, in order toinitiate the décomposition reaction of the hydrogenperoxide, nitrogen can also be injected at the same time asthe injection of hydrogen peroxide, in order to create in 012645 10 the décomposition chamber 1 a volume of gas whichfacilitâtes the expansion of the oxygen released by thedécomposition reaction of the hydrogen peroxide.

In order to limit the volumes of reagent injected inthe case of pipes of great lengths, nitrogen can be used asbooster fluid for the reagent.

The device can be used at high pressures inparticular, for example at least 20 bars.

Figure 2 diagrammatically represents a secondembodiment of the device according to the invention, whichcomprises a décomposition chamber 21 mounted in a watertight fashion around a riser 22 which connects a head 38 ofa subsea well 3 7 for the production of hydrocarbons to thesea surface, which riser comprises a safety cut-off 36.

The décomposition chamber 21 is filled with a catalystwhich promûtes the décomposition reaction of the reagentand comprising at least one element selected from the groupconstituted by manganèse, vanadium, palladium and theirmixtures.

The device also comprises means for supplying areagent which comprise a réservoir 24 for the reagent 25connected by a pipe 26 to the décomposition chamber througha valve 27 with an adjustable opening and a non-returnvalve 28.

In order to eliminate the deposits of hydrates of gasor of paraffins présent on the interior wall of the riser22 and the wall of the éléments mounted downstream of thedevice according to the invention, the valve 27 isprogressively opened so as to inject reagent into thedécomposition chamber 21. On contact with the catalyst 23,the reagent décomposés producing a large quantity of heat 012645 11 which heats the hydrocarbons which circulate in the riser22, via the wall of said riser.

In turn, the hydrocarbons heat and dissolve thedeposits of hydrates of gas or of paraffins downstream ofthe section of the riser 22 on which the décompositionchamber 21 is mounted.

The quantity of heat provided to the hydrocarbons incirculation is controlled by action on the opening of thevalve 27 for a shorter or longer period of time.

The products of the décomposition of hydrogen peroxidecannot return to the réservoir 24 due to the inlet non-return valve 28 and they are partially evacuated by theoutlet pipe 31 through the outlet non-return valve 32.

The device according to the invention also comprisesmeans for injecting a flushing fluid such as nitrogen inorder to eliminate the products of the décomposition of thereagent in the décomposition chamber 21.

These means for injecting a flushing fluid comprise aréservoir 33 for the storage of nitrogen under pressureconnected to the pipe 26 downstream of the valve 27 by apipe 35 through an inlet valve 34 for the nitrogen withadjustable opening.

After an injection of reagent into the décompositionchamber 21, the valve 27 is closed and the inlet valve 34for the nitrogen is open, in order to produce a flow ofnitrogen inside the chamber 21 which carried away theresidual products of the décomposition of the reagent.

Thus, thanks to the device according to the invention,the deposits of hydrates of gas or of paraffins can beremoved from the walls of the hydrocarbon producingequipment, in particular for high depths, withoutdisturbing production. 012645 12

Another advantage of the device according to theinvention is its simplicity of mounting and design whichmake it very reliable.

Yet another advantage is the possibility of heatingoil capital equipment under high pressures, thus at greatdepths, which can exceed 3000 m.

Examples

The following examples illustrate the présentinvention without however limiting its scope.

Instrumentation and test conditions

In these examples, the tests were carried out in a 100ml stainless Steel autoclave, in which a glass jacket hasbeen placed in order to limit the heat loss by diffusion inthe reactor mass.

The reagent, hydrogen peroxide, is introduced via a200 ml pressure dropping funnel. The reactor is moreoverequipped with a pressure sensor, a température probe, asafety valve calibrated to 230 bars and a valve connectedto a vent.

At the start of the test, the solid catalyst isintroduced into the reactor, then the autoclave ispressurized by injection of nitrogen. Hydrogen peroxide (10ml) is introduced into the dropping funnel which is alsopressurized with nitrogen to a pressure slightly higherthan that of the reactor (approximately 25 bars) . Openingthe valve connecting the dropping funnel to the reactorallows the almost instantaneous injection of the hydrogenperoxide into the reactor containing the catalyst. Thereaction is followed by a rise in température. The initialtempérature of the reactor is 20 ± 1°C. 012645 13

The tests were carried out with an aqueous solution ofstabilized hydrogen peroxide (the stabilizer is based onpyrophosphate, phosphate and tin dérivative) comprising 35%hydrogen peroxide by weight, relative to the total weightof the solution.

The tests were carried out principally with powderedcatalysts.

Different processes were used to evaluate thedeactivation of the catalysts: keeping the reaction medium in the reactor andinjecting a second time 10 ml of 35% hydrogen peroxidesolution. This means carrying out the reaction with a morediluted hydrogen peroxide solution (approximately 20%); - recycling the catalyst by separating it from theliquid by decanting and starting the reaction again in thesame way as with new catalyst (injection of 10ml of 35%hydrogen peroxide solution).

Example 1

Palladium catalyst - the effect of the mass ofcatalyst

In this example, several tests were carried out of thedécomposition of 10ml of hydrogen peroxide in aqueoussolution at 35% using palladium supported at 2% by weighton alumina, sold by ENGELHARD and in the form of a finepowder (average particle diameter: 40 μπ\) as catalyst.

The tests were carried out with 100, 500 then 1000 mgof catalyst.

The initial pressure was 80 bars. The catalyst wasrenewed in each test so as to eliminate potentialdeactivation phenomena. 012645 14

The change in température as a funet ion of time wasmeasured.

The results appear in Figure 3.

It is noted that in ail cases, the reaction startsrapidly. With 100 mg of catalyst, there seems to be a briefinduction period (approximately 1 minute), before thereaction starts. With 500 or 1000 mg, décomposition ispractically immédiate.

The different tests carried out with the same mass ofcatalyst show that the results can be reproduced.

Example 2

Palladium catalyst - the effect of pressure

In this example, several tests were carried out of thedécomposition of an aqueous solution of hydrogen peroxideat 35%, with an initial pressure of 80 bars for the firstperiod, then at 160 bars.

The catalyst was the same as in Example 1. The mass ofcatalyst was 500 mg. The catalyst was renewed in each test.

The change in température as a function of time wasmeasured.

The results appear in Figure 4.

It is noted that with this catalyst the décompositionreaction of hydrogen peroxide still takes place at 160bars, even if the pressure has a slightly négative effecton the reaction.

Then, in another test, the reaction was carried out at160 bars, then, at the end of the reaction the pressure wasreduced to 1 bar.

The change in température as a function of time isshown in Figure 5.

It is noted that under high pressure, even if thereaction possibly remains incomplète, the catalyst is not 012645 15 irreversibly poisoned, since the reaction restarts when thepressure is lowered appreciably.

Example 3

Palladium catalyst - the effect of recycling thecatalyst

In this example, 500 mg of catalyst from Example 1 wassubjected to 6 recyclings by separating it from the liquidby decanting and starting the reaction again in the sameway with new catalyst.

Each time the reaction is carried out under an initialpressure of 80 bars, with an aqueous solution of hydrogenperoxide at 35%.

The change in température as a function of time, aftereach addition of 10 ml of 35% hydrogen peroxide, is shownin Figure 6.

It is noted that the deactivation of the catalystseems to be very low.

Example 4

Ca talys t : manganèse

In this example, the effectiveness of the manganèsewas tested as regards the décomposition of 10 ml of anaqueous solution of hydrogen peroxide at 35%.

Each time the reaction was carried out with 1 g ofunsupported catalyst in powder form, under an initialpressure of 80 bars.

The change in température as a function of time isrepresented in Figure 7.

It is noted that the activity of the recycled catalystis greater than that of the new catalyst.

Similar results were observed during tests with 0.5 gof catalyst in powder form. 012645 16

Other tests were carried out with 1 g of previouslyoxidized manganèse and 10 ml of an aqueous solution ofhydrogen peroxide at 35% and 10 ml of a stabilized aqueoussolution of hydrogen peroxide at 20% by weight relative tothe total weight of the solution.

The results are shown in Figure 8.

It is noted that the catalyst remains active even at160 bars, whatever the concentration of the aqueoussolution of hydrogen peroxide.

Example 5

Ca talys t: vanadium

In this example, the ef fectiveness of vanadium wastested as regards the décomposition of 10 ml of an aqueoussolution of hydrogen peroxide at 35%.

Each time the reaction was carried out with 0.5 g ofunsupported catalyst in powder form, under an initialpressure of 80 to 160 bars.

The change in température as a function of time isrepresented in Figure 9.

The pressure has a less marked négative effect thanfor manganèse or palladium. A test was carried out by reinjecting hydrogenperoxide into the reactor, without taking out the waterwhich was produced by the previous décomposition reaction(which means undertaking the reaction with hydrogenperoxide at 20%). In this case, there is an inductionperiod of a few minutes until the température peaks.

Comparative example 1

Ca talys t : Iron oxi de

In this example, the ef fectiveness of a mass catalystprincipally constituted by iron oxide was tested as regardsthe décomposition of 10 ml of an aqueous solution of 012645 17 hydrogen peroxide at 35%. This catalyst, sold by SUD CHEMIEunder the name Styromax-4, also contains molybdenum (<5%Mo03) , calcium (<5% CaOH) and potassium (13% K2CO3) .

The reaction was carried out with 1 g of groundcatalyst, under an initial pressure of 20 bars.

No increase in température was detected at the end ofthis test (température variation lower than 5°C) .

Comparative example 2

Catalyst: Platinum mesh

Under conditions similar to comparative example 1 theeffectiveness of a wire mesh formed from platinum wires wastested (1.2 g, 100 mesh).

Comparative example 3

Catalyst: silver

Under similar conditions to comparative example 1,except for an initial pressure of 80 bars and a catalystmass of 0.5 g, the ef fectiveness of a catalyst based onsilver, supported on alumina and containing 15.7% Ag and 0.1% Ce by weight, was tested.

When the catalyst is new, a maximum température of43°C is obtained (rise in température of 22°C), which isnoted after reaction for 3 minutes. However, after thefirst recycling of the catalyst, the injection of 10ml ofhydrogen peroxide 35% only leads to a rise in maximumtempérature of 5°C, which is observed after reaction for 12minutes.

Thus this catalyst based on silver deactivates veryquickly.

Claims

012645 18 CLAIMS

1. Process for the décomposition of hydrogen peroxideat high pressure, in which hydrogen peroxide is decomposedat a pressure of at least 20 bars using a solid catalystcomprising at least one element selected from the groupconsisting of manganèse, vanadium, palladium and theirmixtures.
2. Process according to claim 1, characterized in thatthe pressure is at least 80 bars.
3. Process according to claim 1 or 2, characterized inthat the catalyst comprises manganèse and/or palladium.
4. Process according to claim 3, characterized in thatthe catalyst comprises partially oxidized manganèse.
5. Process according to one of claim 1 to 4,characterized in that the catalyst is supported on amaterial support, which is inert under the reactionconditions.
6. Process according to one of daims 1 to 5,characterized in that the catalyst is a supported catalystbased on palladium only or in a mixture with one or severaléléments selected from platinum, gold and iridium.
7. Process according to one of daims 1 to 6,characterized in that the hydrogen peroxide is in the formof an aqueous solution. 012645 19
8. Process according to claim 7, characterized in thatthe aqueous solution contains less than 90% and preferablyless than 70% by weight of hydrogen peroxide.
9. Process according to claim 7 or 8, characterized inthat the solution is stabilized.
10. Process according to one of daims 1 to 9, toproduce heat, oxygen and/or steam.
11. Device for heating an equipment (2), comprisinga chamber (1) for the décomposition of a reagent • equipped with means for supplying hydrogenperoxide (4, 6, 7, 8), • containing a solid catalyst (3) comprising atleast one element selected from the group consistingof manganèse, vanadium, palladium and their mixtures,and • having a shape which is able to cooperate withthat of the equipment (2) in order to heat it; and - means for évacuation (11, 12) of the products resulting from the décomposition.
12. Device according to claim 11, characterized in that it also comprises means for injection (13, 14, 15) of a flushing fluid inside of the décomposition chamber (1).
13. Device according to claim 11 or 12, characterizedin that the interior wall of the décomposition chamber (1)is covered with a material which is résistant to hightempératures. 012645 20
14. Device according to one of daims 11 to 13,characterized in that the catalyst comprises manganèseand/or palladium. 5
15. Use of a device according to one of daims 11 to14, under a pressure of at least 20 bars.
16. Use according to daim 15, at a pressure of under10 least 80 bars.