HK1163008A - Dual vessel reactor - Google Patents

Description

Double-container reactor

Technical Field

The present invention relates to a reactor for high pressure high temperature reactions, and more particularly, to a dual vessel reactor.

Background

Many reactions occur requiring high temperatures and pressures and are therefore carried out in reactors. Thus, the reactor typically has an outer pressure vessel to withstand the pressure within the reactor. A dual vessel reactor has an inner vessel in which the reaction can be carried out. The inner vessel is heated to the reaction temperature by an external source or by the reaction itself. The outer vessel is typically a pressure vessel and has a relatively large thickness compared to the wall of the inner vessel, so the reactor is able to handle higher reaction pressures.

Some chemical reactions such as devulcanization of rubber require temperatures as high as 350 ℃. Therefore, the doors in the outer vessel require the use of a metal ring to seal the doors with the reactor when in the closed position. Rubber seals cannot be used because the high temperature of the reactor, particularly the outer vessel, can damage the seals and can lead to failure of expensive seals and safety issues when no pressure is contained anymore.

Metal seals such as metal American Petroleum Institute (API) rings are expensive, can only be used once, and therefore increase the cost of running the reaction in the reactor. In addition, reactors having an outer vessel that experiences higher operating temperatures experience higher corrosion rates on the metals used in the outer vessel, thus requiring the use of expensive metals such as stainless steel or other alloys that are equally expensive to manufacture. Any increase in the outer vessel temperature increases the corrosion rate. Furthermore, it is difficult to find a conventional coating such as paint that can be used to protect steel at high temperatures.

It is one possibility to cool the seal with water, and water-cooled seals are available. However, cooling a large metal flange containing the seal with water will cause the flange to operate at a lower temperature, and will therefore cause a significant amount of condensation thereon and heat transfer thereto. Neglecting for the moment the costs associated with such heat consumption which will ultimately limit the temperature of the reactor, that is to say the heat added to heat the vessel is lost by condensation on the flange. Therefore, water cooling the seal is undesirable.

Thus, there is a need for: a dual vessel reactor for use in reactions having high reaction temperatures, the dual vessel reactor having an outer vessel adapted to work with a non-metallic seal; and a method of conducting a reaction in a reactor, wherein the outer vessel of the reactor does not exceed the operating temperature of the non-metallic seal or has an operating temperature below the reaction temperature.

Disclosure of Invention

In one exemplary embodiment, there is provided a dual vessel chemical reactor comprising:

an outer container (outer vessel);

a reactor lid on the outer container, the reactor lid being openable for access to the inner container;

an inner container (inner vessel) within the outer container for containing a liquid, the inner container being in atmospheric communication with the outer container;

a heat source for heating the liquid in the inner container;

a seal for sealing the reactor lid and the outer container when in a closed position;

an inner container lid for covering the inner container;

wherein the outer vessel is substantially separated from the inner vessel during operation using a non-condensable gas.

In another exemplary embodiment, the reactor as described above further comprises:

a non-condensable gas input for inputting the non-condensable gas into the outer vessel.

In another exemplary embodiment, a method is provided for maintaining an outer vessel at a temperature below a reaction temperature while conducting a reaction in a dual vessel chemical reactor having an inner vessel in atmospheric communication with the outer vessel and substantially separable from the outer vessel. The method comprises the following steps: adding a non-condensable gas to the reactor; heating the liquid in the inner vessel to produce a vapour (vapour); and substantially separating the non-condensable gas in the outer vessel from the vapour in the inner vessel.

In another exemplary embodiment, a method of conducting a chemical reaction in a dual vessel chemical reactor having an inner vessel in atmospheric communication with an outer vessel and substantially separable from the outer vessel is provided. The method comprises the following steps: adding a non-condensable gas to the reactor; adding reactants to the liquid in the inner vessel; heating the liquid in the inner vessel to produce a vapour; and substantially separating the non-condensable gas in the outer vessel from the vapour in the inner vessel.

Drawings

FIG. 1 is a schematic view of a prior art reactor in which the operating temperature of the outer vessel exceeds the operating temperature of the rubber seal;

FIG. 2 is an exemplary schematic diagram of one embodiment of a dual vessel chemical reactor;

FIG. 3 is a graph illustrating test results of one embodiment of the present invention operating at different initial pressures of non-condensable gases at a range of temperatures;

FIG. 4 schematically depicts a cross-sectional view of an exemplary inner vessel for use in a dual vessel reactor;

FIG. 5 schematically depicts a cross-sectional view taken along line A-A' in FIG. 4;

FIG. 6 schematically depicts a view taken along the line B-B' in FIG. 4;

FIG. 7 depicts, in flow diagram form, an exemplary method of maintaining an outer vessel at a temperature below the reaction temperature; and

FIG. 8 depicts, in flow diagram form, an exemplary method of maintaining the outer vessel at a temperature below the reaction temperature.

Disclosure of Invention

The present invention provides a dual vessel reactor and a method for performing a reaction using the same, which sufficiently separates an inner vessel from an outer vessel during a reaction using a non-condensable gas and limits heating of the outer vessel when water vapor (steam) from the inner vessel condenses on an inner surface of the outer vessel. The heating of the outer container is limited by condensing water vapor or other vapors from the inner container, thereby maintaining the operating temperature of the outer container below an upper threshold of the operating temperature of the seal used to seal the door in the outer container. The lower outer vessel temperature also reduces corrosion and allows the use of more conventional coatings such as paint to protect the metal.

A prior art dual vessel reactor is shown in fig. 1, which shows a reactor 5 having an inner vessel 10 inside an outer vessel 20. The reactor 5 has a reactor lid 60 sealed to the outer vessel 20 using a metallic API ring 70. A nitrogen environment 25 is established within the reactor 5. The heater 30 heats the liquid in the inner vessel 10, and a reaction container (reaction container) may be placed in the inner vessel 10. The heating of the inner vessel 10 and inner vessel liquid 15 causes the outer vessel 20 to increase in temperature (e.g. its temperature will rise until it reaches the operating temperature of the inner vessel) and causes a metal seal such as a metal API seal 70 to have to be used.

Fig. 2 is an exemplary schematic diagram of one embodiment of a dual vessel chemical reactor 100 in which the inner vessel 120 is separated from the outer vessel 110 during operation using a non-condensable gas. The cooling of the outer vessel 110 resulting from this separation will be explained in more detail below.

The chemical reactor 100 has an inner vessel 120 for containing a liquid 115. The liquid 115 may be a reaction solvent for dissolving or suspending the reactants, one of the solutions for providing heat transfer to the reaction vessel 210 when the solution is heated, or may be a liquid phase reactant for reacting with the suspended reactants or the reactants in the reaction vessel 210. The liquid may be water which forms water vapour when heated or may be another liquid which forms vapour when heated. The liquid 115 may be any organic or inorganic liquid, preferably having a boiling point above about 25 ℃. For the purposes of this disclosure, the term steam is used to include water vapor and liquid vapor.

The outer vessel 110 encloses the inner vessel 120 and forms a pressure vessel of the chemical reactor 100 together with the reactor lid 140. The outer vessel is typically made of a corrosion resistant alloy of suitable thickness to withstand the reaction pressures experienced during the chemical reactions conducted in the reactor 100. The outer vessel may be made of coated steel to resist corrosion and does not have to be made of expensive stainless steel. For example, the outer container 110 may be made ofOrIs made into. Some coatings for the outer container 110 may include plasma plating, hot plating, or weld overlays. The reactor lid 140 can be an automated lid or a manually operated lid that is sealed to the outer container 110 by a seal 150 when in a closed position. The seal 150 may be, for example, but not limited to, a rubber O-ring or the like. It is understood in the art that the use of O-rings depends on the temperature and the chemicals with which they are exposed. For steam and temperatures below 200 deg.C, materials made from Ethylene Propylene Diene Monomer (EPDM), silicone rubber, and mixtures thereof,Polyacrylate,Fluorosilicones or aflafs^TMThe finished O-ring. An even wider choice is made if the temperature of the outer vessel 110 is kept below 100 ℃ throughout the reaction. If necessary, the outer container 110 may be cooled so that it does not exceed a predetermined temperature. Such additional cooling may be performed, for example, by air or water cooling, but is not limited thereto.

The inner container lid 125 covers the inner container 120 but does not hermetically close the inner container 120 and the outer container 110. When the 125 is in place, the inner container 120 is not sealed to the outer container and the pressure between the inner container 120 and the space between the inner container 120 and the outer container 110 is equalized. The lid 125 may have one or more holes or valves, such as, but not limited to, flapper valves, that allow the pressure in the inner container 120 to equalize with the pressure between the inner container 120 and the outer container 110. Such an arrangement also prevents or minimizes any damage to the inner container 120 if the pressure in the inner container 120 changes rapidly (i.e., the vapor is vented). The apertures or valves allow for pressure equalization between the inner vessel 120 and the outer vessel 110 throughout the reaction.

The heat source 130 is used to heat the liquid 115 in the inner vessel 120. The heat source 130 may be any suitable heat source suitable for heating the liquid in the reactor. For example, a flange-over-the-side immersion heater (or a ribbon heater) may be used, or a ribbon heater that heats the exterior of the inner vessel 120 may be used. Alternatively, external heating of the liquid 115 may be performed using a circulation heater, wherein the liquid 115 is pumped outside the reactor 100, externally heated (by electricity, gas, etc.), and then pumped back into the inner vessel 120. Alternatively, a steam injector for injecting heated steam may be used, as described in co-pending canadian patent application 2,582,815, which is incorporated herein by reference.

As discussed in more detail below, vapor from the liquid 115 in the inner vessel 120 condenses on the outer vessel 110 during the reaction that cools the outer vessel 110. An optional pump 170 may be used to recycle the liquid condensed on the walls of the outer vessel 110 using the pipe 160.

The reactor 100 utilizes non-condensable gas between the vessels 110 and 120 to limit condensation of the steam on the inner walls of the outer vessel 110 and thus limit heating of the outer vessel 110 by the steam and counteract the increase in reactor operating pressure by the addition of non-condensable gas. Non-condensable gases are gases that do not condense on the walls of the outer vessel 110 under the operating conditions (temperature and pressure) of the reactor 100. They may be supplied at room temperature as compressed gases, including, for example, inert and non-inert gases, and including oxygen, nitrogen, air, argon, methane, ethane, ethylene, hydrogen, helium, carbon monoxide, nitrogen oxides, combinations thereof, and the like. To accomplish this, during operation, the non-condensable gas is dispensed sufficiently into the space between the inner vessel 120 and the outer vessel 110 and the vapor is dispensed into the inner vessel 120, thereby reducing or counteracting the effects of dalton's law. Comparative examples will be used to illustrate these effects as well as the separation of non-condensable gases from the steam and the operation of the reactor 100.

The inner container 120 may be constructed of any suitable material, such as corrosion resistant alloys and alloys with corrosion resistant coatings. Rare alloys (exotic alloys) may be used in the construction of the inner container 120, since the inner container 120 is much thinner than the outer container 110 and therefore less expensive to manufacture. Non-limiting examples of alloys that may be used to make the inner vesselIllustrative examples are stainless steel,Hastelloy (hastelloy), and the like.

Comparative examples

The following comparative examples are illustrative and applicants do not wish to be bound by theory.

A schematic diagram of a dual reactor (dual reactor) without separation of non-condensable gases is shown in FIG. 1. The dual reactor 5 has no lid and is used to illustrate one of the problems that have been overcome with the dual vessel reactor and the method of carrying out the reaction as described herein with reference to figures 2 and 3. Reactor 5 contained water in the inner reactor and the remaining space was filled with compressed nitrogen. For example, nitrogen was set at the following pressures: when the water is heated to a certain temperature (e.g., 180 ℃), it will produce a partial pressure of 150psi (1034 kpa). When the water is heated to this temperature, the steam produces a partial pressure of water of 150psi (1034 kpa). Using Dalton's law, the pressure in the vessel would be 300psi (2068 kpa). As can be seen from this embodiment, it is undesirable to add nitrogen or other non-condensable gas to the vessel because it increases the operating pressure of the vessel and therefore the cost of the vessel, since a higher operating pressure requires a thicker metal in the construction of the outer pressure vessel.

In a reactor such as that described herein, for example with reference to fig. 2, a non-condensable gas such as nitrogen is added to the reactor in fig. 2 from a non-condensable gas reservoir 180, for example by using a valve 190, via, for example, an input 200. It should be understood that the non-condensable gases may be added to the reactor 100 using any suitable method, and that the reactor design is not limited to the method or apparatus used to input the non-condensable gases. Non-condensable gases may be introduced through a series of valves (which may or may not be computer controlled) and their pressures monitored using pressure gauges. When introducing non-condensable gases during the reaction, the introduction of non-condensable gases by computer control is a preferred method. For example, a non-condensable gas is added such that when nitrogen has been sufficiently dispensed in the space between the inner container 120 and the outer container 110, it will generate a pressure of about 150psi (1034 kpa). When liquid 115 is heated in inner container 120 to a point where the vapor generates a pressure of 150psi (1034kpa), it builds up a vapor pressure in inner container 120, and this pushes the non-condensable gas from inner container 120 into the space between containers 120 and 110 (i.e., the vapor distributes the non-condensable gas sufficiently into the space between inner container 120 and outer container 110, while the vapor enters inner container 120). The allocation process is a dynamic process. As the liquid is heated, a vapor is generated and a mixture of non-condensable gas and vapor flows out of the inner container 120 into the space between the inner container 120 and the outer container 110. However, because the walls of the outer vessel 110 are cooler than the steam, the steam condenses thereon. It reduces the pressure between the inner vessel 120 and the outer vessel 110 as the vapor condenses, and this causes even more vapor and nitrogen to flow out of the inner vessel 120. In this way, the vapour entering the space between the inner vessel 120 and the outer vessel 110 continues to cool on the cooler walls of the outer reactor and eventually drives most of the non-condensable gas into the space between the inner vessel 120 and the outer vessel 110, causing the vapour to be distributed into the inner vessel 120 and the non-condensable gas into the space between the two vessels 110 and 120. The non-condensable gas in the space between the inner and outer vessels 120, 110 then acts as an insulator between the inner and outer vessels 120, 110-this limits heat transfer and maintains the outer vessel 110 cooler than the inner vessel 120 without allowing the vapor to constantly condense thereon as shown in figure 1. A situation is reached where the pressure in the space between the inner vessel 120 and the outer vessel 110 is about 150psi (1034kpa) (primarily from non-condensable gases) and an equal pressure (primarily from steam) is observed in the inner vessel 120.

The outer container 110 may be cooled using external cooling means, if necessary.

Fig. 4 depicts in schematic form an inner vessel 400 that may be used as the inner vessel 120 of the reactor as described above. Fig. 5 and 6 depict schematically upwards a cross section of the inner container 400 taken along the line a-a 'and the line B-B', respectively. The inner container 400 has an outer shell 402 and an inner shell 404. The inner case 404 is covered by a cover 406. The inner housing 404 is not sealed by the cover 406 and liquid is able to freely pass between the inner housing 404 and the outer housing 402. The inner shell 404 provides a vessel in which reactions can occur.

The housing 404 is covered with a cover 408. The cover 408 has a ring 409 that seals the interior of the inner container 400; however, the cover 408 also includes a channel 412 that allows vapor, non-condensable gases, or a combination of both to pass between the interior of the inner container 400 and the exterior of the inner container. The channel 412 allows the interior of the inner container to be at a similar pressure to the interior of the outer container in which it is enclosed.

The inner container includes a plurality of ports 410, 414, 416. The port 410 may be used to vent the vapor or water vapor from the interior of the inner vessel 400 after the reaction is complete. This off-gas can for example be used for other reactions taking place in other reactors. Venting the vapor through the port 410 helps to cool the inner vessel 400 after the reaction is complete. Port 414 may serve as an inlet port to fill the inner vessel with the desired liquid and any possible other reactants required for the reaction. Port 416 may serve as an outlet to empty liquid from the interior of the inner container. The port 416 may also be used to circulate and possibly heat the liquid inside the inner container 400. For example, liquid may be circulated from the port 416 and input back into the inner container 400 via one of the ports 414.

A heater 418 including a plurality of heating elements 420 is suspended within the inner shell 404. The heater 418 is secured to a flange 422 on the housing 402. The heater 418 may be secured to the flange using, for example, screws. The flange 422 allows the wires 424 to pass through the housing 402 while maintaining the integrity of the housing 402.

The inner container 400 may be located on a bottom surface of the outer container, depicted in fig. 4 as 428. The inner container may be raised off bottom surface 428 by a support structure such as, for example, posts 426.

FIG. 7 depicts, in a flow chart, a method 700 of maintaining an outer vessel at a temperature below a reaction temperature. The method can be used to maintain the temperature of the outer vessel while conducting the reaction in a dual vessel chemical reactor. The process begins by adding a non-condensable gas to a dual vessel reactor (702). The amount of non-condensable gas added varies depending on the type of control used during the reaction. For example, a final amount of non-condensable gas may be added at the beginning, in which case no more non-condensable gas need be added during the reaction. Alternatively, a lower amount of non-condensable gas may be added initially and additional non-condensable gas added during the reaction. Regardless of the type of control used, an initial amount of non-condensable gas is added to the dual vessel reactor. As the non-condensable gas is added, the liquid in the inner vessel is heated (704). The heating of the liquid brings the liquid temperature to the reaction temperature. The vapor is formed from the heated liquid. The non-condensable gases and the vapor are separated such that the vapor is substantially distributed within the interior of the inner container (704). The distribution of this vapour to the interior of the inner container prevents condensation of the vapour on the walls of the outer container, which would raise the temperature of the outer container.

The steam is separated as a result of the non-condensable gases. The partial pressure of the non-condensable gas is maintained above the partial pressure of the vapour which, in combination with the passage between the inner and outer vessels, limits the escape of vapour from the interior of the inner vessel.

FIG. 8 depicts in a flow chart a method 800 similar to method 700; however, the method 800 also includes monitoring the temperature of the reaction to maintain a pressure differential between the non-condensable gas and the vapor. The process begins by adding an initial amount of non-condensable gas to a dual vessel reactor (802) and then heating the liquid (804) to a reaction temperature. The method monitors the liquid temperature (806) and determines if the reaction is complete (808). If the reaction is complete (YES, 808), the process is complete. If the reaction is not complete (no, 808). The method measures the partial pressure (P) of steam generated by the temperature of the liquid_V)(810). The method then determines the partial pressure (P) of the non-condensable gas_nc) Whether or not P is less than or equal to_VPlus the pressure difference (Δ) to be maintained_pres)(812). If less than or equal to (yes, 812), more non-condensable gas is added to the dual vessel reactor (814) to restore the desired pressure differential. The method then returns to monitoring the temperature of the liquid (806). If P is_nc＞P_V+Δ_pres(NO, 812), the method returns to monitoring the temperature of the liquid (806).

It is to be understood that the above-described methods may be used to carry out a variety of chemical reactions. The inner vessel may contain a solid or large reactant and more may be added to the liquid being heated.

Experimental examples

A series of experiments have been performed to verify the concept outlined above, which uses a non-condensable gas in the space between the two vessels 110 and 120, allowing the outer vessel 110 of the reactor 100 to operate at a much cooler temperature than the inner vessel 120. The results of the experiment are shown in fig. 3.

In the experiment, a pressure vessel (outer vessel 110) 36 inches in diameter by 10 feet and rated at 150psi (1034kpa) was used. Having an inner container 120 that can hold about 800L of liquid, in this case water. The water is heated by the immersion heater 130. Any open space between the inner container 120 and the outer container 110 is minimized and two flapper valves are mounted in the lid 140 to allow pressure equalization between the containers 110 and 120.

In a series of experiments, water was heated from 25 ℃ to 180 ℃ in the inner container 120 and held at that temperature for 1 hour. A pre-adjusted pressure of nitrogen (e.g., 25 ℃, 40psi (276kpa)) is used and the temperature and pressure of the water in the inner vessel 120 is monitored as the water is heated to 180 ℃. The results are shown in figure 3 along with the vapor pressure curve for water.

It can be seen that the curve for experiments with initial pressures up to 60psi (414kpa) merges with the curve for water, whereas the curve for initial pressures of 95psi (655kpa) does not merge and is much higher.

The experimental data has been supplemented with a computer model, and there is a crossover point with respect to the experimental setup (i.e., the volume of the inner vessel 120 and outer vessel 110 containing non-condensable gas, etc.). That is, at an initial pressure of non-condensable gas, such as nitrogen, of about 70psi (483kpa) and at the end point, i.e. 180 ℃, all of the nitrogen in the inner vessel 120 is purged out of the inner vessel 120, and the pressure of the nitrogen in the space between the inner vessel 120 and the outer vessel 110 (which now contains the nitrogen initially in this space plus the nitrogen purged from the inner reactor) is equal to the pressure of the vapour in the inner vessel 120. That is, steam and nitrogen have been separated.

It must be emphasized that even if the reactor starts with a nitrogen pressure of 70psi (483kpa), the final pressure is 150psi (1034kpa), which is also the saturated vapour pressure of water at 180 ℃, and this means that no nitrogen remains in the inner vessel, otherwise the pressure will be higher (by dalton's law).

For non-condensable gases having an initial pressure above 70psi (483kpa), it is not possible to purge all of the non-condensable gas out of the inner vessel 120 as it would cause the pressure between the vessels 110 and 120 to exceed the vapour pressure in the inner vessel 120. A portion of this "surplus" remains in the inner vessel 120 and results in a pressure that exceeds the vapor pressure of water (see 95psi (655kpa) curve).

For non-condensable gases having an initial pressure below 70psi (483kpa), when the water is heated to 180 ℃, there is not enough non-condensable gas to fill the space between the two vessels 110 and 120 where the non-condensable gas is at 150psi (1034kpa), and there is a phenomenon that will be referred to as "starving" of the non-condensable gas in the space between the vessels 110 and 120. This deficiency is taken up by the steam, which may condense on the walls of the outer vessel 110 if the walls are cooler than the steam temperature. The greater the deficit, the greater the heat flow to the outer reactor will be as the steam condenses thereon. For example, during the experiment, when the initial pressure was 8psi (55kpa) relative to 60psi (414kpa), another 25L of water condensed on the walls.

Thus, for the experiment used above, a useful initial pressure is about 70psi (483 kpa). Under these conditions, and without any cooling of the outer vessel 110, the temperature rise of the vessel 110 is limited to 40 ℃ versus 155 ℃ if there is no non-condensable gas therein.

Even though the above-described method limits the temperature rise to about 40 ℃, the majority of the heating that occurs stems from the fact that: the vapor is also purged out of the inner vessel 120 along with the non-condensable gases. This can be further minimized by adding non-condensable gases as the water is actually heated (not before the experiment), so that an excess non-condensable gas pressure of, for example, 10psi (69kpa) is maintained (i.e., 10psi (69kpa) above the equivalent vapor pressure), so that it is not necessary to purge non-condensable gases out of the inner vessel 120 as the water is heated.

Exemplary procedure for carrying out the reaction

Looking at the process in a broader scope, some options for adding non-condensable gases are, but not limited to, the following:

1. starting at 150psi (1034kpa), and the gas was vented as the pressure rose.

2. Starting at a pressure ideally located around the intersection.

3. Non-condensable gas is added as the liquid is heated to maintain an overpressure (higher than the pressure of the steam).

In options 1 and 2, a non-condensable gas is added and the vapor pushes it out of the inner container 120 into the space between the inner container 120 and the outer container 110. The process of pushing the non-condensable gas out of the inner container 120 also results in the transfer of the vapor into the space between the containers 110 and 120, after which the vapor condenses onto the outer container 110. In option 3, this transfer is limited by the addition of non-condensable gas as required. A small non-condensable gas pressure (e.g. 10psi) is used in the reactor 100 at the start of the process. As the liquid 115 is heated and the vapour pressure in the inner reactor rises, non-condensable gas is added to the space between the vessels 110 and 120 in order to maintain a pressure above the vapour pressure in the inner vessel 120. For example, the overpressure may be 10 psi. In this way, non-condensable gases are purged out of the inner vessel 120, with concomitant heat transfer from the vapour being minimised. 10psi is an example that can be used for lower pressure reactions (e.g., up to 150psi), but the pressure can be much higher for operation at higher pressures. It should be understood that the vapor pressure of the liquid 115 can be determined by measuring its temperature as it is heated and calculating its vapor pressure.

In terms of how well the inner vessel 120 is sealed, a half inch of space is initially provided around the immersion heater flange. This yields about 14in²(90cm²) Open space (relative to the outer container 110). This open space allowed an additional 12L of water to condense during the above experiment under the same test conditions.

Although the above example uses a pressure of 150psi, the reactor 100 can be operated at much higher pressures of 500psi or 1000psi, depending on the needs of the particular reaction being carried out. The concept of separating non-condensable gases from steam for cooling the outer vessel 110 is also applicable at high pressure and the above embodiments are merely illustrative and not limiting. The thickness of the pressure vessel increases as the pressure increases. Reaction pressures of up to 2000psi may be carried out in a reactor as described herein.

Devulcanization of the rubber may be carried out in a reactor as described herein, with a reaction pressure of no more than 2000psi and a reaction temperature of no more than 350 ℃. As described above, the outer container 110 is kept cold by minimizing the thermal contact between the two containers 110 and 120, and by insulating the inner container 120 from the outer container 110 using separate non-condensable gases and vapors. Some heat transfer through the non-condensable gas is observed between vessels 110 and 120, as well as any vapor heat transfer that condenses on outer vessel 110, of course. By introducing non-condensable gases during the reaction and maintaining the non-condensable gases above the excess pressure of the steam as described in option 3 above, the condensation of the steam can be reduced. In one embodiment, the non-condensable gas is introduced by computer control.

The present invention has been described in terms of several exemplary embodiments. It will be apparent, however, to one skilled in the art that many changes and modifications can be made without departing from the scope of the invention as defined in the claims.

Claims (27)

1. A dual vessel chemical reactor comprising:

an outer container;

a reactor lid on the outer container, the reactor lid openable to access the inner container;

an inner container located within the outer container for containing a liquid, the inner container being in atmospheric communication with the outer container;

a heat source for heating the liquid in the inner container;

a seal for sealing the reactor lid and the outer container when in a closed position;

an inner container lid for covering the inner container;

wherein the outer vessel is substantially separated from the inner vessel during operation using a non-condensable gas.

2. The reactor of claim 1, wherein the reactor further comprises:

a non-condensable gas input for inputting the non-condensable gas into the outer vessel.

3. The reactor of claim 2, wherein the reactor further comprises:

a non-condensable gas reservoir in communication with the non-condensable gas input; and

a valve for opening and closing the non-condensable gas input into the outer vessel.

4. The reactor of claim 1, further comprising a passageway in the inner vessel, in the inner vessel lid, or between the inner vessel lid and the inner vessel for communicating the inner vessel to the outer vessel atmosphere.

5. The reactor of claim 4 wherein said passageway comprises a valve.

6. The reactor of claim 5 wherein the valve is a flapper valve.

7. The reactor of claim 1, wherein the seal is one of: metal seals, rubber O-rings or composite gaskets.

8. The reactor of claim 1 wherein said seal is a rubber O-ring.

9. The reactor of claim 8, wherein the rubber O-ring comprises one of: ethylene Propylene Diene Monomer (EPDM), silicone rubber,Polyacrylate,Fluorosilicones or aflafs^TM。

10. A reactor as claimed in claim 1 wherein the outer vessel is maintained at or below 225 ℃ during operation at reactor temperature.

11. The reactor of claim 1 wherein the outer vessel is made of a corrosion resistant alloy.

12. The reactor of claim 11, wherein the corrosion resistant alloy is one of: stainless steel,Or

13. The reactor of claim 1, wherein the outer vessel is made of an alloy coated with a coating selected from the group consisting of: paint, enamel, plasma coating, hot coating, galvanizing, electroplating and weld overlay.

14. The reactor of claim 1, wherein the inner vessel is separated from the inner vessel lid by an opening to allow pressure between the inner vessel and the outer vessel to equalize during reactor operation.

15. The reactor of claim 1, wherein the inner vessel is separated from the inner vessel lid using a flapper valve to allow pressure between the inner and outer vessels to equalize during reactor operation.

16. A method of maintaining an outer vessel at a temperature below a reaction temperature while conducting a reaction in a dual vessel chemical reactor having an inner vessel in atmospheric communication with and substantially separate from the outer vessel, the method comprising the steps of:

a) adding a non-condensable gas to the reactor;

b) heating the liquid in the inner container to produce a vapour; and

c) substantially separating the non-condensable gas in the outer vessel from the vapor in the inner vessel.

17. The method of claim 16, wherein the non-condensable gas is maintained at an overpressure relative to the vapour pressure of the liquid in the inner vessel when heating the liquid.

18. The method of claim 17, wherein the non-condensable gas is added to the space between the inner vessel and the outer vessel during the reaction to maintain an overpressure relative to the vapour pressure of the liquid to substantially separate the non-condensable gas in the outer vessel from the vapour in the inner vessel.

19. The method of claim 16, wherein the non-condensable gas is distributed in the outer vessel and the vapor is distributed in the inner vessel by condensing the vapor in the space between the outer vessel and the inner vessel on the outer vessel.

20. The method of claim 16, wherein the non-condensable gas is added to the reactor prior to step b).

21. The method of claim 16, wherein the non-condensable gas is added at a predetermined pressure, whereby after step c) the non-condensable gas is at the reaction pressure.

22. The method of claim 16, wherein the non-condensable gas is one or a combination of: oxygen, nitrogen, air, argon, methane, ethane, ethylene, hydrogen, helium, carbon monoxide, nitrogen oxide or nitrous oxide.

23. The method of claim 16, wherein the non-condensable gas is nitrogen.

24. A method of conducting a chemical reaction in a dual vessel chemical reactor having an inner vessel in atmospheric communication with and substantially separated from an outer vessel, the method comprising the steps of:

a) adding a non-condensable gas to the reactor;

b) adding reactants to the liquid in the inner vessel;

c) heating the liquid in the inner container to produce a vapour; and

d) substantially separating the non-condensable gas in the outer vessel and the vapour in the inner vessel.

25. The method of claim 24, wherein the chemical reaction is devulcanization of the rubber.

26. The method of claim 25, wherein the non-condensable gas is maintained at an overpressure relative to the vapour pressure of the liquid in the inner vessel when heating the liquid.

27. The method of claim 26, wherein the non-condensable gas is added to the space between the inner vessel and the outer vessel during the reaction to maintain an overpressure relative to the vapour pressure of the liquid to substantially separate the non-condensable gas in the outer vessel from the vapour in the inner vessel.