GB2103472A

GB2103472A - Tank cleaning apparatus and method

Info

Publication number: GB2103472A
Application number: GB08222258A
Authority: GB
Inventors: John Keith Tooley
Original assignee: POTTERS OILS Ltd
Current assignee: POTTERS OILS Ltd
Priority date: 1981-08-14
Filing date: 1982-08-02
Publication date: 1983-02-23

Abstract

A method of cleaning oil from tanks comprises jetting hot water into the tank, pumping an oil and water mixture from the tank, and separating the oil from the water. The method may be carried out by feeding water from tank 15 to steam generator 20 to from steam which is used to heat water, also supplied from tank 15, in hydraulic jet mixer 51, the hot water being pumped to jetting device 23 via pump 24. The oil/water mixture from the tank is pumped via pump 27 to a separator 11, which separates the oil from the water. Water from the separator may be reheated and recirculated via line 51. A heat exchanger 60 may be provided to heat the oil/water mixture on its way to the separator. Oil may be removed via outlet 35. <IMAGE>

Description

SPECIFICATION Tank cleaning apparatus and method This invention relates to a tank cleaning method and apparatus for carrying out the method, for cleaning oil from tanks.

There is, in oil tanks, a build-up of old oil, which becomes viscous and difficult to remove. Removal is usually assisted manually, but initially the oil is often heated to assist removal by application of steam to the interior of the tank, after which large pumps are used to remove as much as possible of the oil.

The application of steam takes a long period and is very expensive and the following manual work can take months in some instances. Apart from the expense and obvious unplesantness ofthe work, there is also danger to personnel from fumes.

In accordance with the present invention, a method of cleaning oil from a tank comprises jetting hot water into the tank, pumping an oil and water mixture from the tank, and separating the oil from the water. Preferably, the separated water is reheated and re-jetted into the tank. The jetting and pumping operation may be continuous or intermittent, e.g., alternate.

The invention also resides in apparatus, for use in cleaning oil from a tank, comprising a water supply, a heating device for heating water from the supply, a jetting device for receiving heated water and jetting it into the tank, a first pump for pumping water to the jetting means, an oil/water separation device, and means connectibleto an outlet of the tank and connected to the separation device through a second pump for pumping oil/water mixture from the tank to the separation device.

It has been known, prior to the present invention, to wash out a tank with hot water after the oil has been removed by other means. It is also inevitable that some of the steam used for heating a tank, in a conventional cleaning method, condenses, so that hot water and oil are pumped off together.

It has not previously been proposed, however, to jet hot water into the tank to effect loosening and heating ofthe oil. The method according to the invention, as described hereafter, permits cleaning oftanks automatically in a very short period as compared with the conventional methods. The actual cleaning operation is consequently much cheaper and, in addition, the tanks can be put back into service quickly. Manual cleaning, with its danger and disadvantages, is unnecessary, and labour costs can be very much reduced.

Reference is now made to the accompanying drawing, which is a diagrammatic representation of apparatus according to the invention.

The apparatus shown is carried in practice on a vehicle, so that the apparatus can readily be moved to different sites for tank cleaning.

The apparatus comprises a header tank 15, which is filled with water from a mains line 17. Water is fed bya line 19fromthe headertankto a steam generator 20 in the form of an electrically operated flash boiler. Steam from the generator is fed by a line 50 to a hydraulic jet mixer 51, which mixes the steam with water in order to heat the water. Water is fed to the mixer bylines 16 and 52 from the header tank.

The hot water is forced into a tank to be cleaned and a spinning, jetting device 23 is fitted into an inlet to the tank for this purpose. Such devices are well known and spin under the water pressure. The hot water is fed to the jetting device 23 through a pump 24 and a hose 25, carried on a reel.

Afurther hose 26 has an inlet device fitted to the outlet from the tank being cleaned and this inlet device leads to a pump 27, which pumps a water/oil mixture from the tank to an inlet point 28 of an oil interceptor 11, which separates the oil from the water.

The oil interceptor 11 has several compartments, three being shown in the described embodiment and referenced 14, 13, and 12 respectively. The compartments are separated by partitions 54, 55. The inlet point 28 is connected to an upright pipe 30, which opens near the top ofthefirst compartment 14. Afurther pipe 31 leads from near the bottom of the first compartment 14 to an outlet 31a at the upper part of the next second compartment 13. A further pipe 32 similarly leads from near the bottom of the second compartment to an outlet 32a at the upper part ofthe next, third compartment 12. An outlet 56 is provided near the bottom of the third compartment 12. Sight glasses 34 are provided in the compartments to facilitate monitoring.

The water/oil mixture from the tank being cleaned is pumped to the top of the pipe 30 and water settles at the bottom ofthefirst compartment 14, with the oil floating on it. Under the pressure exerted by the pump 27, water passes from the first compartment to the second compartment 13 through the pipe 31, as the first compartment 14 fills with oil. The water is then forced through to the first compartment 12 through the pipe 32. Oil can be taken off th rough an oil outlet 35 atthe top ofthe first compartment.

The outlets 31a, 32a can be closed by valves (not shown) if required, and drainage points are provided in the compartments.

The water outlet 56 from the first compartment leads through the line 52 to the mixer 51, so that the water is reheated and recirculated. Water is fed from the header tank 15 to the mixer 51 to top up the system.

The water/oil mixture being fed to the interceptor 11 is reheated before it enters the interceptor to ensure good flow. The heating is carried out by a heat exchanger 60, which is heated by steam from the generator 20 passed through a line 61. Con densed steam is returned to the header tank 15 by a line 62, so that water in the header tank is preheated.

The interceptor 11 accommodates at least one heat exchanger 70, which receives steam through line 21 from the generator 20. Return is again to the header tank 15 by a line 71.This is provided for heat ing the oil in the interceptor, if necessary, should the oil be allowed for any reason to become cold.

The steam generator 20 and the pumps 24, 27 are powered by an electrical generator 40, which includes a fuel driven motor and receives its fuel from a supply 41. An electrical control apparatus 42 permits control of the electrical generator and pumps individually or may permit programmed operation. The water may be pumped in continu ouslyfor example as the oil/water mixture is drawn off, or the two operations may be alternate in a repetitive cycle.

Steam may be passed directly into the tank prior to the cleaning operation to displace noxious and/or inflammable gases.

Claims

1. A method of cleaning oil from a tank comprising jetting hot water into the tank, pumping an oil and water mixture from the tank and separating the oil from the water.

2. A method according to Claim 1, comprising reheating the water separated from the oil and returning it to the tank.

3. A method according to Claim 1 or 2, including further heating the oil and water mixture removed from the tank prior to separation.

4. A method according to any preceding claim, in which the water fed to the tank is heated by steam.

5. A method according to Claim 4, as appendant to Claim 3, wherein said further heating is effected by heat exchange from steam and the condensed steam is used to preheat the water fed to the tank prior to the step of Claim 3 of heating the water by steam.

6. A method of cleaning oil from a tank substantially as herein described.

7. Apparatus, for use in cleaning oil from a tank, comprising a water supply, a heating device for heating water from the supply, a jetting device for receiving heated water and jetting it into the tank, a first pump for pumping water to the jetting means, an oil!water separation device, and means connectible to an outlet of the tank and connected to the separation device through a second pump for pumping oil/water mixture from the tank to the separation device.

8. Apparatus according to Claim 7, wherein the separation device has an oil outlet and a water outlet, the latter being connected to the jetting device for recirculation of the water, means being provided for heating the recirculated water before it reaches the jetting means.

9. Apparatus according to Claim 8, wherein the means for heating the recirculated water is said heating device for heating water from the supply.

10. Apparatus according to Claim 7,8 or 9, wherein the heating device includes a steam generator.

11. Apparatus according to Claim 10, wherein the heating device includes a steam/water mixer having a steam inlet connected to the steam generator and a water inlet connected to the water supply.

12. Apparatus according to Claim 11 as appendant to Claim 9, wherein the water outlet from the separator is also connected to the water inlet of the mixer.

13. Apparatus according to any one of Claims 7 to 12, including a further heating means arranged to heat the oil'water mixture being fed from the tank to the separator.

14. Apparatus according to Claim 13 as appendant to Claim 10, 11 or 12 wherein the further heating means comprises a heat exchanger connected to the steam generator.

15. Apparatus according to Claim 14 wherein the water supply includes a reservoir and the heat exchanger is connected with the reservoir for returning condensed steam from the exchanger to the reservoir.

16. Apparatus according to any one of Claims 7 to 15, including a heat exchanger in the separator.

17. Apparatus according to any preceding claim, mounted on a vehicle and including an electrical generator for providing power to the pumps and the heating device.

18. Apparatus, for use in cleaning oil from a tank, substantially as herein described with reference to the accompanying drawings.