EP1200166A2

EP1200166A2 - Vapour management system

Info

Publication number: EP1200166A2
Application number: EP00945491A
Authority: EP
Inventors: Dennis William Mount
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-07-07
Filing date: 2000-07-07
Publication date: 2002-05-02
Also published as: WO2001003810A3; JP2003504177A; AU5958300A; WO2001003810A2; CA2277449A1

Abstract

A vapour recovery system and method for volatile chemicals which enhances the efficiency and safety of the process of recovering the vapour is disclosed. The volatile substance is vaporized in a distillation unit under the control of a computerised heating system. The resulting vapour is first directly condensed by bubbling the vapour directly into the liquid phase of that volatile substance. Any vapour that remains after having passed through said liquid phase accumulates above the liquid phase and is allowed to escape into a vapour management module. The vapour management module facilites efficient condensation of the vapour by allowing heat exchange from the vapour to a material contained within said vapour management module. Upon cooling in the vapour management module, the vapour condenses, and can run back into the liquid phase through which it had passed when in the vapour phase. The vapour management module has an exhaust that is substantially free of the vapour.

Description

VAPOUR MANAGEMENT SYSTEM BACKGROUND OF THE INVENTION

Volatile solvents are used in many industrial processes in which the volatile solvent is

used for cleaning purposes. As a result of such use the volatile solvent becomes

contaminated with foreign matter. Due to the cost of such volatile solvents, environmental

concerns, and the cost of disposing of such contaminated volatile solvents, it is desirable to

maximize the use that can be made of the volatile solvent by removing the contamination

from it by recycling it into the purified solvent form for further use in the industrial

process.

In addition to industrial processes requiring purification and recovery of volatile

solvents, there are also many industrial processes in which it is important to control the

escape of vapour from volatile liquids. The escape of vapour from such volatile liquids

represents an environmental and occupational health concern, and a financial cost in that

the vapour is lost. The current procedure for preventing or reducing vapour loss is to

provide a scrubbing system on tanks, containers or stacks in which the volatile liquid, or

the vapour is stored. While the scrubbing system may reduce or even eliminate the

environmental concerns of vapour loss, it does not overcome the cost of the loss of such

vapour. Further, the used scrubbing material may in itself present an environmental

disposal problem. Examples of such containers include oil storage tanks and gasometers.

Other examples include the containment of vapours from stacks or from recycled solvents

in processes such as gun-washing in automotive paint shops. Currently the common practice for purifying and recovering contaminated volatile solvents is distillation and condensation. Typically the solvent is boiled such that a vapour

is formed. The vapour is then allowed to pass through a spiral or serpentine tube where it

is cooled by heat exchange with air blown across the tube or with another liquid which

flows around the outside of the tube. The heat exchange leads to condensation into the

liquid phase inside the tube. This liquid phase then runs off into an open collection vessel.

This method has a disadvantage in that as the vapour condenses in the tube, it has the

potential for the build-up of back pressure within the distillation vessel which gives rise to

a "champagne effect", i.e. vigorous boiling and cavitation, rather than controlled

evaporation. This has the consequence of a potential safety hazard, reduced efficiency, and

increased operating costs.

Further, the run off into an open collection vessel used in conventional systems leads to a

loss of volatile solvent to the environment. This loss of solvent from an open collection vessel to the environment reduces the recovery of the solvent and causes an environmental hazard for operators around such tanks.

A further problem with conventional processes is the presence of uncondensed vapour

in the collection vessel. Further, sealing the collection vessel, or the connection to the

collection vessel from the distillation vessel in conventional systems causes pressure

buildup unless vented. Such a pressure buildup or back pressure caused by uncondensed

vapour in the collection vessel, or the conduit leading thereto can result in "foaming" in the distillation vessel. In order to prevent buildup of back pressure in the collection vessel and consequently the distillation vessel, the collection vessel must be vented. Similarly, any

vessel in which, or into which, a volatile solvent is placed requires a vent in order to avoid

vapour lock. Conventional methods of venting lead to loss of volatile solvent in the form of

vapour into the atmosphere, thereby further reducing the efficiency of conventional

methods of distillation and condensation and creating an environmental hazard.

Hence, there is a need for a method of condensing a volatile vapour which will

ideally prevent any significant loss of volatile solvent from the system, and enhance

recovery and condensation of the vapour to liquid. The consequence of this increased

recovery of volatile vapour is a decrease in the overall cost of the vapour recovery, improved safety of the system, and a reduction in potential environmental harm.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a vapour recovery system for efficient and safe recovery of a vapour from a solvent comprising:

a distillation module comprising a distillation chamber for the solvent and heating

means for heating the chamber to vaporize the solvent;

a direct condensation module comprising a container for condensing the vapour and

collecting the solvent in the liquid phase;

conduit means for directing the vapour substantially without condensation from the

distillation chamber to the direct condensation module, the conduit means sloping

downwardly towards the distillation chamber to allow any condensate formed within the conduit to drain into the distillation chamber; a vapour management module for condensing vapour remaining uncondensed by the

direct condensation module; and

a vapour outlet located above the surface of the liquid in the direct condensation

module, the vapour outlet communicating with the vapour management module to allow for

passage of vapour from the direct condensation module to the vapour management module.

In a further aspect of the invention, a vapour management system comprises a

container containing heat absorbing material, a vent, a vapour inlet and means for guiding

vapour from the vapour inlet through the heat absorbing material to the vent. The vapour

may be guided through the container by means of a conduit extending between the vapour

inlet and the vent, the conduit passing through the heat absorbing material. Alternatively,

the container may contain solid heat absorbing material which is permeable to vapour and

condensation and through which the vapour passes from the vapour inlet to the vent.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic view of a preferred embodiment of the vapour recovery

system comprising a distillation unit, a direct condensation module and a vapour

management module.

Figure 2 is a sectional view of a preferred embodiment of the distillation unit of the vapour recovery system illustrated in Figure 1. Figure 3 is a sectional view of a preferred embodiment of the distillation unit o the vapour recovery system illustrated in Figure 1 , in which the heating means is located at the

upper end of the distillation chamber.

Figure 4 is a sectional view of a preferred embodiment of a lined distillation chamber

of the vapour recovery system illustrated in Figure 1.

Figure 5 is a sectional view of a preferred embodiment of the direct condensation

module of the vapour recovery system illustrated in Figure 1.

Figure 6 is a sectional view of a preferred embodiment of the vapour management module of the vapour recovery system illustrated in Figure 1.

Figure 7 is a partial sectional view of an alternative embodiment of the vapour

management module in which embodiment the heat absorbing material is in a solid form.

Figure 8 is a schematic representation of a heating control system that is employed in

the distillation module to control the rate of vaporization of solvents.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The preferred embodiment of a vapour recovery system for solvents according with

the invention is shown in Figure 1. In this embodiment the vapour recovery system [10]

comprises a distillation module [1], a direct condensation module [11] and a vapour management module [31]. In this embodiment of the invention the solvent or mixture of

solvents to be recovered is heated in the distillation module [1] to generate solvent vapour.

This solvent vapour is then directed through a downwardly inclined conduit [12] to a

vapour inlet [13] to the direct condensation module [11]. This downwardly inclined conduit

[12] in a preferred embodiment of the invention extends within and toward the bottom of

the condensation module [11]. There is substantially no condensation of the vapour in the

conduit [12] but any condensate which does form runs down into the condensation module

[11] and, therefore, no back-pressure is created by the condensate formation. The

condensation module [11] is charged with a coolant liquid [14] which is the same solvent as

that being distilled. Thus, as will be described in more detail hereinafter, in the

condensation module [11], the vapour is subjected to a first round of cooling in which the heat absorbing material is the solvent to be recovered in the liquid phase [14]. Some vapour

may pass through and exit from this liquid [14]. This vapour, plus air, then passes from

the condensation module [11] through the vapour outlet [32] into the vapour management

module [31]. In the vapour management module [31] the vapour air mixture is required to pass through a heat-absorbing material [44] and this heat exchange process leads to further

condensation of vapour from the mixture. The remaining gases then leave the vapour

management module [31] through a vent [42] and are substantially free of any solvent

vapour. Preferably, any condensate formed in the vapour management module [31] runs

back into the condensation module [11]. However the condensate formed in the vapour management module [31] can also be run into a secondary container, if desired. In a preferred embodiment illustrated in Figure 2, the distillation module [1]

comprises a distillation chamber [2] in which the contaminated solvent or solvent mixture

[S] to be recovered is collected. The distillation chamber [2] is closed to prevent the escape

of any vapour generated therein other than through the conduit [12]. The size of the

conduit [12] and the opemng of the vapour inlet [13] to the direct condensation module [11]

should be adequate to allow free passage of vapour from the distillation chamber [2]

without resulting in a pressure build up in the distillation chamber [2]. Further, the conduit

[12] is ideally positioned toward the upper end of the distillation chamber [2] since the hot

vapour will rise. This distillation chamber [2] sits within a larger heating vessel [3]

containing an oil bath [5]. The heating vessel [3] is provided with one or more heating

elements [4] immersed in the oil and, in operation, each heating element [4] heats the oil

[5], which in turn heats the distillation chamber [2] at least until the solvent [S] within the

distillation chamber reaches its boiling point and vapour is generated. Once the boiling

point of the solvent is reached, the power supplied to the heating element is controlled to regulate the rate of vaporization of the solvent until the solvent is substantially all

evaporated.

It is essential that the oil [5] have a boiling point higher than that of the solvent to be

recovered or, in the case of a solvent mixture, the boiling point of the highest boiling component of the mixture. In addition, the oil [5] should not be flammable within the

temperature ranges in which the distillation module [1] will operate. In the preferred

embodiment, the oil [5] in the heating vessel [3] will surround a substantial portion of the

distillation chamber [2] (for example, to the level 5a in Figure 2) to ensure that there is sufficient heat to maintain the evaporated solvent in the vapour phase at least as far as the

conduit [12].

While the preferred embodiment describes the means for heating the distillation

chamber [2] as comprising a heating vessel [3] containing one or more heating elements [4]

immersed in oil [5], alternative means of heating the distillation chamber [2] are possible.

In one alternative embodiment, the means for heating the distillation chamber [2] is an

infrared lamp [L] located toward the upper end of the distillation chamber [2] as illustrated

in Figure 3. The heating provided by such a lamp can be regulated by rheostatic control of

the intensity of the lamp. In this embodiment of the invention, the solvent [S] in the

distillation chamber [2] is heated from the top down. This top heating provides the

advantage that only the top layer of the liquid to be distilled needs to be heated to initiate

distillation. Further, as the distillation progresses, it is only the energy of vaporization for

the top layer of the liquid that needs to be provided to continue the distillation.

The distillation chamber [2] is preferably provided with an anti-vacuum valve [V]

(Figure 2) which prevents vapour from escaping from the distillation chamber [2] , but is

triggered to allow entry of outside air when the pressure within the distillation chamber [2]

falls below atmospheric. As the distillation chamber [2] cools down following distillation, the pressure in the distillation chamber [2] falls. Since the conduit [12] provides a passage

from the distillation chamber [2] to the vapour inlet [13] which communicates with

the liquid condensed in the condensation module [11], without the anti-vacuum valve [V] in the distillation chamber [2], the reduction in pressure would lead to a back-flow situation with condensed solvent being drawn from the condensation module [11] into the conduit

[12] through the vapour inlet [13], and thence into the distillation chamber [2].

In an alternative embodiment of the distillation module [1] there is a line feeding

contaminated solvent directly into the distillation module [1] through source inlet [7]. In

this embodiment, a means for preventing flow-back from the condensation module [11] to

the distillation chamber [2] is provided. In addition, the anti- vacuum valve can be shut off

such that any negative pressure created in the distillation chamber [2] as it cools can be

used to draw more contaminated solvent for recycling into the distillation chamber [2] through source inlet [7] . This acts as a natural pump which can be used as part of the

process since it allows continuous flow, without the need for separate pumps.

One aspect of the current invention is a heating control system, as illustrated schematically in Figure 8, that is employed in the distillation module to control the rate of

vaporization of the solvent or solvents. In the distillation module, the solvents are

separated from the impurities in the solution and may also be separated from each other.

The control system is designed to do this in a time efficient manner while also minimizing

operator intervention.

The heating control system has three key components, a variable heating means [61],

for example, a plurality of the heating elements [4] of Figure 2, a temperature sensing

means [62], for example, a temperature probe [6] (see Figure 2) which may be either a platinum thermistor or a thermocouple, and a control computer [63], for example, a microprocessor with required software. The control computer [63], by use of a control

law, selectively triggers relays [64] which are in series between a power supply and heating

means [61] and which energize the heating means [61] in an ordered manner, in response

to temperature reference signals input to the control computer [63] from the temperature

sensing means [62]. In a preferred embodiment, which is especially useful where a

mixture of solvents is to be distilled, an important element of this control system is a

control law that allows the system to operate in 2 modes. The first mode is a solvent mode

where the system begins to heat the mixture of solvents until the boiling point of the

solvent with the lowest boiling point is reached. At the temperature of that lowest boiling

point the power delivered to the heating means is maintained at a constant level to provide

the energy of vaporization at a desired rate, until the first solvent has been substantially

distilled from the solution. Once the first solvent has substantially distilled, the power

provided to the system is no longer used to provide the required energy of vaporization and

no further heat is being lost as a result of heated vapor, and therefore the temperature of the liquid in the distillation chamber [2] begins to rise. The power provided to the heating

means can again be increased until the boiling point of the next solvent is reached. This

control cycle is repeated until the solvents have all been vaporized.

The second mode is the water mode. In the water mode of the control system there is

no advantage to stepped regulation of the temperature. Water has a relatively high specific

heat capacity and requires significant energy input in order to boil. Therefore, in the water

mode, it is not necessary to regulate the temperature as closely. In other words, in the water mode the distillation chamber and its contents can be heated continuously until the evaporation is complete, at which time a timed heating cycle can then be brought into

effect. The two modes of the control system allow the distillation chamber to be used for

vaporization of water and organic solvents. Distillation can take place with a mixture of

water and organic solvents, or either alone, with no significant foaming.

The power applied to the heating means [61] during the vaporization phase for any

particular solvent provides the energy of vaporization for that solvent. Therefore,

controlling the power applied to the heating means [61] also controls the rate of

vaporization, and is used to maintain an equilibrium with the condensation rate of the

vapour in the system.

In the embodiment shown in Figure 2, the temperature sensing means is a probe [6]

that is used to monitor the temperature of the distillation chamber [2] . The probe [6]

detects an increase in temperature of the distillation chamber [2] as the solvent is heated.

The rate of evaporation of solvent from the distillation chamber [2] is regulated by means

of the control system of Figure 8.

Controlling the rate of vaporization of the solvent in the distillation chamber [2] means that the vapour pressure in the distillation chamber [2] is closely regulated. Since

the pressure differential between the distillation module [1] and the condensation module

[11] is important, this strict regulation of vapour pressure will enhance the efficiency of

vapour recovery. In addition, by closely regulating the rate of vaporization of the solvent, it is possible to reduce the required mass for solvent condensation in the condensation

module [11].

After the liquid in the distillation chamber [2] has evaporated, a timed heating cycle

is brought into effect by means of a timer system (not shown) which maintains the

temperature in the distillation chamber [2] for a predetermined period of time. This post-

evaporation heating ensures that essentially all of the solvent to be recovered is distilled.

Further, the continued heating drives off any residual solvents and bakes any contaminants

in the distillation chamber [2] so that the resulting solids can be disposed of more

conveniently at a lower cost and with reduced environmental problems as compared to

unbaked contaminants. In the embodiment of the invention as illustrated in Figure 4, the

distillation chamber [2] is lined with a bag [8] such that, following baking, the entire bag

[8] containing the baked contaminants can be disposed of. The bag [8] is stable within the

temperature range of the distillation chamber [2]. In addition, it is important that the bag

[8] be inert with respect to the solvents to be distilled. It is clear that the bag [8] can be

made of any material provided it is heat stable, does not react with the solvents to be

distilled, and is non-permeable, such as Teflon (trade-mark for polytetrafluoroethylene) .

As can more clearly be seen by reference to the preferred embodiment illustrated in

Figure 5, the condensation module [11] is comprised of a container [20] into which the

vapour to be recovered enters via vapour inlet [13]. The condensation module is primed using a predetermined volume of the solvent to be recovered in the liquid phase [14]. This liquid [14] is free from contamination. The vapour entering the condensation module [11] is directed by the inlet [13] to pass beneath the surface [15] of the liquid [14] such that the

vapour bubbles through the liquid.

Ideally, the vapour entering the condensation module [11] is forced to the bottom of

the container [20] by the inlet [13]. Some of the vapour will be cooled by the liquid [14]

such that it condenses and combines with the liquid. As a result of such condensation the

level of liquid in the container [20] will rise. The condensation may lead to an increase in

the temperature of the liquid [14] if there is no external source for cooling the liquid.

However, the corollary increase in the volume of liquid [14] in the container [20] means

that the vapour which subsequently enters the container [20] must travel a greater distance

through the liquid [14]. In addition, the coolest liquid will fall to the bottom of the

container [20] where the vapour to be condensed is entering the condensation module [11].

Some vapour may pass through the liquid [14] and accumulate above the surface [15]

in the upper volume [21] of the container [20]. The only way this accumulated vapour can

escape from the container [20] is by passing through a vapour outlet [32] positioned above

the upper volume [21]. The vapour, having entered the vapour outlet [32] from the condensation module [11], then passes from the outlet [32] into the vapour management

module [31].

In a preferred embodiment of the invention, as illustrated by Figure 6, the vapour

management module [31] comprises a sealed chamber [45] containing a serpentine tube [43] communicating with the vapour outlet [32] at its entrance end and a vent [42] at its exit end. The mixture of air and solvent vapour exiting the condensation module [11] is

directed via the outlet [32] through the tube [43], which is surrounded by a cooling

medium [44] inside the sealed chamber [45] . The cooling medium [44] absorbs heat and therefore causes further condensation of the vapour so that substantially all of the vapour

escaping from the condensation module [11] is condensed and prevented from reaching the

atmosphere through vent [42]. The medium [44] can be any suitable coolant medium.

Ideally, the medium [44] will provide sufficient heat absorption for condensation of all

vapours, such that only air exits the system through vent [42].

In one preferred embodiment of the invention, the medium [44] is water mixed with a salt

to form a crystallized mass which has a low expansion rate and can be contained safely in

the sealed chamber [45] . The tube [43] allows condensed solvent to flow back by gravity

through the outlet [32] into the condensation module [11], while allowing the remaining uncondensed vapour (which is a very small amount, if any) and air to exit the vapour

management module [31] to the atmosphere through the vent [42]. The condensate can

continue to flow counter to the air/vapour flow, through the outlet [32] and be collected in

the container [20] of the condensation module [11], or in a separate container.

The container [20] may be provided with a tap [T] , which can be used to drain the

liquid [14]. Ideally, this tap is situated below the surface [15] of the liquid, and the closer

to the base of the container [20], the more liquid [14] can easily be drained off. The advantage of this arrangement is that liquid [14] being collected can be accessed at any time without losing vapour from the system. Further, condensed liquid [14] can be removed

from the container [20] without interruption of the condensation.

If desired, a downwardly sloping overflow pipe [D] may be provided in the container

[20] at a predetermined overflow level. As the level [15] of liquid [14] rises to that

overflow level, a fixed volume of liquid is maintained in the container [20]. Any liquid

[14] in excess of that volume enters the overflow pipe and runs by gravity into a collection

vessel. This provides an advantage in that a large volume of material can be used as the

coolant.

In another embodiment of the vapour management module [31], as illustrated in

Figure 7, the air/solvent vapour mixture is allowed to pass from the outlet [32] to the vent [42] without the use of a tube [43]. In this embodiment, the material [44] is a solid material

for example, ball bearings or glass chips, through which the vapour and condensate are

able to pass. The material may be prevented from falling back through the outlet [32] into

the container [20] either by selecting the size of the material particles to be sufficiently

large, or by the insertion of a support member [46] which is permeable to both the liquid

[14] and the air/vapour mixture, but through which the material [44] cannot pass. Maximizing the ratio of the heat exchange surface to the volume of vapour passing into the

vapour management module [31] increases the efficiency of the condensation in the vapour

management module [31]. In accordance with the present invention, the vapour management module [31] can be

designed such that essentially no vapour exits the vent [42] . This is achieved by ensuring

that the rate of heat input does not exceed the rate of heat absorption in the vapour

management module. It is clear that factors such as the rate of vapour flow, the vapour

temperature, the heat absorption properties of the material and the path length through the

vapour management module are important. In one embodiment of the invention, the heat

absorbing material is a crystalline salt, the pipe [43] is of 12mm bore and 75 cm in length,

made of heat conductive metal such as copper, and the heat input to the vapour

management module in the form of vapour is 1500W.

In selecting the appropriate solid material [44] in the above embodiments, ideally the

material should allow the vapour to flow through at approximately atmospheric pressure,

provide the required absorption of heat, and allow the condensed liquid [14] to flow by

gravity back to a reservoir.

Those skilled in the art will appreciate that various combinations of condensation

modules [11] and vapour management modules [31] are possible. Further, it is possible to

use either the condensation module or the vapour management module in isolation from the

system, provided there is an input of vapour to such modules. It is possible to use the

vapour management module [31] to recover vapour from any vent or exhaust. Examples of

situations where the vapour management module [31] could be used are on a vent to an oil

storage tank, a vent on a gasometer, or a vapour stack of a spray booth. In these situations,

the vapour would arise as a consequence of evaporation of the liquid to be recovered. Condensate formed in such vapour management modules can then run back by gravity into

the vent and ultimately back to the container of the liquid to be recovered, or to another

container. It is clear to those skilled in the art that in these situations the heat absorbing material must be cooler than the vapour to be recovered.

Further, while the preferred embodiment utilizes both a condensation module [11]

and a vapour management module [31] and has been found to have excellent results, each

solvent to be recovered will have different requirements. It is certainly possible to subject the vapour to sequential steps of direct condensation and/or to sequential vapour

management modules [31]. The efficiency of vapour recovery will determine the most

suitable module arrangement.

It should be clear that while the preferred embodiments described above describe

specific arrangements of heat absorbing material, variations are possible. For example, it is

not essential to have any liquid in the condensation module [11] prior to initiation of

condensation. Alternatively, any material that absorbs heat from the vapour but does not

chemically react with it would be suitable to use within the condensation module, including

a solid mass or air. A solid inert mass such as rocks or ball bearings are suitable to absorb

heat in the condensation module [11]. Alternatively, air in the condensation module [11]

can rapidly absorb heat from the vapour entering the condensation module [11] since heat exchange is rapid between gases. Any liquid [14] accumulating as a result of condensation

in the condensation module [11] also acts to absorb heat from the vapour. While only specific embodiments of the invention have been described, it is apparent

that various additions and modifications can be made thereto, and various alternatives can

be selected. It is, therefore, the intention in the appended claims to cover all such

additions, modifications and alternatives as may fall within the true scope of the invention.

Claims

CLAIMSTHE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVEPROPERTY OR PRIVILEGE ARE CLAIMED ARE DEFINED AS FOLLOWS:

1. A solvent vapour recovery system comprising:

a distillation module comprising a distillation chamber for said solvent and heating

means for heating said chamber to vaporize the solvent;

collecting the solvent in the liquid phase;

conduit means for directing the vapour substantially without condensation from said distillation chamber to the direct condensation module, said conduit means sloping

downwardly towards said distillation chamber to allow any condensate formed within said

conduit to drain into said distillation chamber;

a vapour management module for condensing vapour remaining uncondensed by said direct condensation module; and

a vapour outlet located above the surface of said liquid in said direct condensation

module, said vapour outlet communicating with said vapour management module to allow for passage of vapour from the direct condensation module to the vapour management module.

2. The apparatus of claim 1 wherein the container holds a heat absorbing material

through which said vapour is passed.

3. The apparatus of claim 2 wherein the heat absorbing material comprises the vapour to

be recovered in its liquid phase.

4. The apparatus of claim 2 wherein the heat absorbing material is air.

5. The apparatus of claim 2 wherein the heat absorbing material is an inert solid mass.

6. The apparatus of claim 2 wherein the heat absorbing material comprises a

combination of the vapour to be recovered in its liquid phase and an inert solid mass.

7. The apparatus of claim 3 or 6 wherein the conduit directs vapour beneath the surface

of said liquid.

8. The apparatus of any one of claims 1 - 7 wherein the conduit directs vapour to the

bottom of said container.

9. The apparatus of claim 3, 6 or 7 wherein the vapour outlet is above the surface of

said liquid.

10. The apparatus of any one of claims 1 - 9 wherein the distillation chamber is located

within an oil bath which is heated by said heating means.

11. The apparatus of claim 10 wherein the heating means comprises one or more heating

elements located within said oil bath.

12. The apparatus of any one of claims 1 - 9 wherein the distillation chamber is heated by

means of an infrared heater located within said chamber.

13. The apparatus of any one of claims 1 - 12 further comprising means for connecting

said heating means to a power supply and a control means for controlling the power

provided by said power supply to said heating means, said control means comprising a

computer, temperature sensing means for sensing the temperature of said distillation

chamber and generating temperature reference signals which are provided as input signals

to said computer and switching means for selectively providing power to said heating

means from said power supply, said computer being programmed to apply control signals

to said switching means to control the amount of power applied to said heating means in

accordance with said input signals received from said temperature sensing means.

14. The apparatus of claim 13, wherein said computer is programmed with a set of

parameters based on the input signals received from the temperature sensing means which,

if exceeded, will activate said switching means to perform an ordered shutdown of said

heating means by selectively activating said switching means to disconnect said heating

means from said power supply.

15. The apparatus of claim 13, wherein the temperature sensing means comprises one or

more platinum thermistor temperature probes.

16. The apparatus of claim 13, wherein said heating means consists of at least one heating element.

17. The apparatus of claim 13, wherein said heating means consists of a direct heating

means.

18. The apparatus of claim 17, wherein said heating means consists of an infrared heating

lamp.

19. The apparatus of claim 13, wherein said switching means comprises one or more

relays.

20. The apparatus of claim 13, wherein said heating means consists of a plurality of

heating elements and said switching means comprises a plurality of relays respectively

connecting said heating elements to said power supply.

21. The apparatus of claim 13, wherein said computer is programmed with a control law

so that when a mixture of solvents including an aqueous component is to be distilled in said

distillation chamber, said computer runs a distillation procedure wherein the heating means

raises the solution to a temperature causing the solvent with the lowest boiling point to

vaporize, the temperature is then maintained until the aforementioned solvent is substantially removed from the solution, at which time the temperature is raised again until

the solvent with the next lowest boiling point begins to vaporize and the process is then

repeated until all solvents have been distilled off.

22. The apparatus of claim 13, wherein computer controls said switching means to vary the input to the heating means to balance the rate of vaporization of a solvent with the rate

of condensation of the same solvent in a separate, but connected, container.

23. The apparatus of claim 1, wherein said vapour management module comprises a

container containing heat absorbing material and a conduit extending between said vapour

outlet of said direct condensation module and a vent, said conduit passing through said heat

absorbing material.

24. The apparatus of claim 23, wherein said vent is at a higher elevation than said vapour

outlet of said direct condensation module.

25. The apparatus of claim 23 or 24 wherein the heat absorbing material is a liquid.

26. The apparatus of claim 23 or 24 wherein the heat absorbing material is crystalline.

27. The apparatus of claim 23 or 24 wherein the heat absorbing material is water mixed with a salt to form a crystallized state.

28. The apparatus of claim 1, wherein said vapour management module comprises a

container containing solid heat absorbing material which is permeable to vapour and

condensation through which said vapour passes from said direct condensation module to

said vent.

29. The apparatus of claim 28 wherein the heat absorbing material is steel ball bearings.

30. The apparatus of claim 28 wherein the heat absorbing material is glass chips.

31. The apparatus of any one of claims 28 - 30 wherein a support member is provided in

said vapour outlet of said direct condensation module, said support member being

permeable to vapour and condensation and impermeable to said heat absorbing material.

32. The apparatus of any one of claims 1 - 31 wherein the container of said direct

condensation module is provided with a drainage means for draining liquid therefrom.

33. The apparatus of claim 32 wherein the drainage means comprises a tap.

34. The apparatus of claim 32 wherein the drainage means comprises an overflow pipe in

said container.

35. A vapour management system comprising a container containing heat absorbing

material, a vent, a vapour inlet and means for guiding vapour from said vapour inlet

through said heat absorbing material to said vent.

36. The apparatus of claim 1, wherein said vapour management module comprises a

inlet and said vent, said conduit passing through said heat absorbing material.

37. The apparatus of claim 35, wherein said vapour management module comprises a

condensation through which said vapour passes from said vapour inlet to said vent.

38. The apparatus of claim 37 wherein the heat absorbing material is steel ball bearings.

39. The apparatus of claim 37 wherein the heat absorbing material is glass chips.

40. The apparatus of any one of claims 37 - 39 wherein a support member is provided in said vapour inlet, said support member being permeable to vapour and condensation and

impermeable to said heat absorbing material.