AU629902B2 - Process and device for evacuating the content of gas spaces of large containers containing pollutant substances - Google Patents

Abstract

Process and device for evacuating the content of gas spaces in large containers, such as tanks and the like, in which one tank is emptied and another tank is filled with substances whose gaseous phase causes stress or damage to the environment or can be recycled, and in which the gas space of the tank to be emptied is filled with a replacement substance and the gas content of the tank being filled is passed through a cooling trap. To simplify this process in order to evacuate the content of the gas space using devices and equipment which are optimally compact and easy to handle and which can be used in all ordinary types of tank vehicles, whether rail or road vehicles, the cooling trap (8) is operated with an inert gas, which is also used as the replacement substance to fill the tank being emptied (2).

Description

41 4 OPI DATE 05/09/90 APPLN. I D 49658 P AOJP DATE 11/10/90 PCT NUMBER PCT/EP9O/00192 INTERNATIONALE ANMELDUNG VEROFFENTLICHT NACH DEM VERTRAG OBER DIE INTERNA\TIONALE ZUSAMMENARBEIT AUF DEM GEBIET DES PATENTWESENS (PCT) (51) Internationale Patentklassiikation 5 (11) Interniationale Veroffentlichungsnummer: WVO 90/09343 B67D 5/06, B65D 90/30 Al (43) Internationales BWlD 53/04 Veroffentlichungsdatum: 23. August 1990 (23.08.90) (21) Internationales Aktenzeichen: PCT/ EP90/00 192 Veroffentlicht A'!it intcrnationalemn Reclzerc/ienberich.

(22) Internationales Auneldedatumn: 6. Februar 1990 (06.02.90) Mit getinderten Anspriklen.

Prioritlitsdaten: P 39 03 938.2 10. Februar 1989 (10.02.89) DE (71)X72) Anmelder und Erfinder: WEIL, Peter [DE/DE]; Hele- 9 ne-Mayer-Ring 10, D-8000 M~nchen 40 (DE).

(74) Anwiilte MEINKE, Julius usw. Westenhellw !g 67, D- 4600 Dortmnund 1 (DE).

(81) Bestimmungsstaaten: AT (europ~iisches Patent), AU, BE (europtiisches Patent), CA, CR (europ~iisches Patent), DE (europtiisches Patent), DK, DK (europtiisches 'Patent), ES (europtiisches Patent), Fl, FR (europtiisches Platent), GB (europqiisches Patent), HU, IT (europtisehes Patent), JP, LU (europgisches Patent), NL (europfiisches Patent), NO, RO, SE (europtiisches Patent), SU, US.

(54)Title: PROCESS AND DEVICE FOR EVACUATING THE CONTENT OF GAS SPACES OF LARGE CONTAINERS CONTAINING POLLUTANT SUBS'-k.NCES (54) Bezeichnung: VERFAHREN UND ANLAGE ZUR ENTSORGUNG DE', GASRAUMINHALTE VON GROSSVOLU- MIGEN BEHALTERN BEI UMWELTBELASTENDEN INHALTSSTOFFEN (57) Abstract 4 'c Process and device for evacuating the content of' gas spaces in large containers, such as tanks and the like, in which one tank is emptied and 4 .dt another tank is filled with substances whose gaseous phase causes stress or damage to the environment or can be recycled, and in which the gas space of the tank to be emptied filled with a replacement substance and the gas content of the tank being filled is passed through a cooling trap. To simpli- a fy this process in order to evacuate the content oa the gas space using devices and equipment which are optimally compact and easy to handle and which can be used in all ordinary types of tank vehicles, whether rail or c.

road vehicles, the cooling trap is operated with an inert gas, which is also used as the replacement substance to ill the tank being emptied (57) Zusamnmenfassung Mit elnem Verfahren und einer Anlage zumn Entsorgen der Gasraurninhalte Von grossvoiumigen Behliltern, wvie Tanks od.

*dgl., bei Entleeren des einen Tanks und Befaillen eines anderen ranks mit Stoffen, deren Gasphase umnweltbelastend, umweltschlldigend oder als Wertstoff zurtickzugewinnen ist, wobei der Gasraumt des sich entleerenden Tanks mit einem Ersatzstoff be.

falkt und der Gasinhalt des sich fflllenden Tanks Oiber eine Kah~falle geleitet wird, soll eine 1_6sung geschaffen werden, mit der die Gasrauminhalte einfach entsorgt werden kt~nnen, wohei die L6sung, so getroffen werden soft, dass die zumn Einsatz kommnen- *den Einrichtungen und Gerfite mbglichst, kleinvolumig und einfach zu handhaben sind, dlass sie auch bei (Iblichen Tankfahrzeugen eingesetzt werden k6nnen, unabhilngig davon, dass dies strassen- oder schienerigebundene Fahrzeuge jind. Dies wird dadurch erreicht, dass die Kflhlfalle mit einem fltissigen Inertgas betrieben wird, wobei das die Kdhlfalle betreibende lnertgas als Ersatzstoff zur Beftillung des sich entleerenden Tanks eingesetzt wird.

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1- Complete Specification The present invention relates to bulk liquid storage and transport, and in particular to a method and apparatus for the evacuation of the gas volume above the liquid in tanks or such like, when emptying one tank and filling another with the liquid. Many such liquids have a gaseous phase which is harmful or damaging to the environment, or is to be recovered for commercial reasons, so that evacuation to the atmosphere is not acceptable. Further, when replacing the liquid contents of a tank with a different liquid it is important to ensure that no gaseous residues of the previous contents remain.

~Frequently, liquid chemicals are not only stored in tanks but also transported by tank vehicles, for example from the producer to the consumer, from the producer to e..storage and from there to the consumer, with the operator of such tank trucks transporting very different products in their vehicles. When emptying such a tank, volatile matter forms in gas volume above the liquid, frequently the 20 gaseous phase of the appropriate product transported, with the gaseous phase escaping at the latest when the tank is

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refilled. In practice the tanks are often opened during an empty running and the ambient air blows out the harmful gaseous phase of the subject matter, discharging it into the environment. If the emptying process is incomplete and the refilling of the tank takes place, it 2is likely to happen that the replacement product may form a dangerous compound with the gaseous phase of the product transported before, this compound may not only be toxic but also, for example, be highly explosive.

The liquid flowing into the tank during filling expels the gas remaining in the tank. To avoid the build up of back pressure when, for example, filling fuel tanks, the so called gas displacement method comes into use, i.e. the gas expelled from the fuel tank is fed to the emptying gas volume of the tank truck to establish equal pressure. The gas displacement method is useful as long as there is only one chemical product transported by the truck.

If a product change takes place, and this is the most frequent case, as containers hardly ever get used for the 15 same product only, the gas displacement method does not work any more. The gas volume contents remaining in a tank truck would contaminate a new product to be transported.

In the worst case chemical reactions (explosions) can occur. For this reason containers are washed or 20 neutralised, as far as water soluble components are concerned. This, however, does not apply for most organic :oe- substances as they often do not mix with water. There also is contaminated water as a side effect, that has to be disposed of at very high costs.

Thus criminal behaviour is highly likely. The transporter makes use of the gas displacement device at the customer, but on the road leaves the dome tops open degassing the tank with the air stream. For reasons of 3environmental protection such behaviour is strictly prohibited. However, there is no feasible solution, as rinsing with water is not successful. As combustible fluids can compound to highly explosive air/gas mixtures, a single spark suffices to lead to disaster.

An object of the invention is to provide a solution for the disposal of gas volume contents in a simple way, with the prerequisite, that facilities and devices to be used are of minimal volume and easy to handle, so they can be applied to common tank vehicles, independently from their being road or rail vehicles.

According to the invention there is provided an apparatus mounted as an integral component of a vehicle for the disposal of gas volume contents of tanks when emptying one tank and filling another tank with materials whose gas phase is harmful to the environment or is to be reclaimed as valuable material, the vehicle including one of the tanks, the apparatus comprising: means for filling the gas volume contents of the tank being emptied with a substitute 20 material; a cooling trap and means for conducting the gas volume contents of the tank being emptied through the cooling trap to substantially recover said gas volume contents, wherein the apparatus further comprises at least one supply means for supplying liquid inert gas to the cooling trap for cooling thereof, and means for conducting the inert gas as the substitute material from the cooling trap into the tank being emptied.

It will be appreciated that the intentional filling of 4the gas volume of the tank being emptied on one hand and the disposal of the gas volume contents of the tank being filled over a condensation trap on the other hand has the advantage of rendering unimportant the question of whether an exchange of products will take place at the next operation or not. The inert substitute material makes the operation of tank vehicles simpler. Alternately, with the installation of a condensation or cooling trap it is possible that the condensing product, after being fed over the condensation trap, can directly be brought back to the consumer, so there will be no volume deficiency for himn in the quantity balance. In the same way as the gas displacement method, the emptying and filling process can take place without the occurrence of pressure differences.

15 The feeding of gases over a condensation trap also has the advantage, that these products condense in the condensation trap and can, if required, be at the consumers' disposal, since they, in practice, pay for them as well. It is also possible to collect the products S 20 precipitated in the condensation trap in containers of S. small volume and use them for different purposes.

Beside the ambient air flowing into the tanks a variety of materials can be considered as substitutes.

DE-A-12 51 233 discloses a method, with which vapours can be recovered on an industrial scale, by leading the vapours over cooling steps. In what way, however, volumes are filled, if a recovery takes place, is not described.

The complete specification rather deals with ambient air.

DE-A-23 37 055 also shows a procedure to recover a petrol-vapour mixture by cooling down a petrol-air mixture so the present hydrocarbons condense or freeze.

A particular advantage of the invention consists in keeping the gas volume filling inert gas ready as a coolant or vice versa using the coolant, after cooling down the gas volumes, as inert gas to fill the gas volume after appropriate evaporisation. Thus the invention utilises the knowledge, that an inert gas/coolant, not harmful to the environment, increases greatly in volume when evaporated.

But it is of advantage to use nitrogen for the operation of the condensation trap and the filling of the gas volume.

The use of nitrogen is preferable as it is frequently available in its liquid form and it increases in volume passing from the liquid to the gaseous phase increases by a factor of 800. In addition to that, nitrogen prevents explosions and is completely harmless to the environment.

Atmospheric nitrogen does not react chemically with air if standard conditions apply, and the forming of peroxide for, for example, air sensitive solvents cannot take place.

The invention preferably uses a temperature range A/iZN between -10 and -50 degrees C for the operation of the L i 6-

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condensation tran to precipitate and condensate the expelled gases. In this temperature range the devices to be put into operation are to be kept at a small size, with the chosen temperatures ensuring, that, for example, at least 80% of the solvents cool below their dew point and can be recovered as condensate products.

The unseized volatile components can for example be fed over an activated carbon installation, also designed at a small size, as considered according to the invention.

If nitrogen is available in the area of the tanks to be treated, the invention preferably uses also the condensation trap as a partial evaporator for the inert gas, in particular the liquid nitrogen, i.e. the operating matter of the condensation trap is simultaneously the substitute gas.

According to a preferred embodiment of the invention an activated carbon filter, for example, can be provided as a residual gas purifier.

As already mentioned before,. different products are frequently transported successively in a tank vehicle and so different residual gas compounds can occur. In this case preferred embodiments of the invention include multiple filters, locked on separately, for different residual gases.

Figure 1 shows a preferred embodiment of the invention and illustrates the basic principle of a installation according to the invention.

Referring now to Figure 1, the installation 1 essentially represents the connection between a first tank -~'-PVIFE;IV131-r~Ur-x~~_ i 7- 2 of a tank vehicle 5 and a second tank 4 connecting the outlet nozzle 5 of tank 2 with the inlet nozzle 6 of tank 4 by a filling tube 7.

In addition, there is a condensation trap 8, having cooling coils, represented schematically, with nitrogen flowing through as indicated with arrow 9. The liquid nitrogen is heated in the condensation trap 8, gasifies and enters the gas volume 11 of tank 2 at its top area 10 wheh the emptying process takes place.

The escaping gas of gas volume 12 of the tank to be filled 4 is fed trough a tube 13 into the cooling chamber of the condensation trap; there it condenses and the condensate so recovered is brought back to the production S" tube 7 by a condensate tube 14 and flows back into the tank 4. Residual gas not condensated is discharged into the environment by a tube 15, with the possibility of having an activated carbon filter installed.

The control and regulation of the whole installation is made in such a way, that there are no pressure differences between the gas volumes 11 and 12 of both tanks 2 and 4, i.e. the evaporating nitrogen can be added in surplus, if bigger volumes are necessary than the operation of the condensation trap requires, or can also operate with a deficit, i.e. gasified nitrogen that is no longer necessary in gas volume 11 can be discharged into the environment.

8- There is also the possibility of installing several cartridges 16 with different filter contents according to the subject matter to be treated. The uncondensated residual gas enters the necessary cartridge 16 by a tube The example described according to the invention can of course be improved in many ways, without departirng from the basic concept. The spatial arrangement of the condensation tra; 8, represented schematically, is not a limiting factor for the invention. On site it can be considered as a fixedly installed part in the area of the tank 4 or also as integral part of the tank vehicle 3 etc.

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Claims (2)

1. 9- THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:- i. An apparatus mounted as an integral component of a vehicle for the disposal of gas volume contents of tanks when emptying one tank and filling another tank with materials whose gas phase is harmful to the environment or is to be reclaimed as valuable material, the vehicle including one of the tanks, the apparatus comprising: means for filling the gas volume contents of the tank being emptied with a substitute material; a cooling trap and means for conducting the gas volume contents of the tank being filled through the cooling trap to substantially recover said gas volume contents, wherein the apparatus further comprises at least one supply means for supplying liquid inert gas to the cooling trap for cooling thereof, and means for conducting the inert gas as the substitute material from the cooling trap into the tank being emptied. An apparatus as claimed in claim i, wherein the inert gas is nitrogen. 3. An -pparatus as claimed in claim 1 or claim 2, including means for maintaining the cooling trap within a .temperature range of minus 100 to minus 50 0 C. An apparatus as claimed in claim 1 or claim 2, wherein i the cooling trap comprise3 means for collecting condensate and means for cleaning residual gases. An apparatus as claimed in claim 4, including an activated charcoal filter for the residual gases. 6. An apparatus as claimed in claim 4, including a plurality of separately connectable filters for different residual gases. DATED this 23rd day of APRIL, 1992 PETER WEIL Attorney: PETER HEATHCOTE Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS e e
2. 11- Abstract A method and a facility is disclosed for disposing gas volume contents of bulky containers, such as tanks or the like, when emptying one tank and filling another with subject matters, having a gaseous phase harmful or damaging to the environment, or which are to be recovered, by filling the gas volume of the emptying tank with a substitute matter and feeding the gas content of the filling tank over a condensation trap. The object of the invention is to provide a solution for the disposal of gas volume contents in a simple way, with the prerequisite, that facilities and devices to be used are of minimal size and easy to handle, so they can be applied to common tank vehicles, independently from their being road- or railborn vehicles. This is realised by operating the condensation trap with a liquid inert gas, which is used as substitute matter for the filling of the emptying tank. I One accompanying drawing is to be published. ~iJ