Process and composition for converting liquid hydrocarbons and fatty substances to solid form, devices for implementing this process and manufacturing this composition, and the use thereof for environmental remediation

Abstract

Process and device for converting hydrocarbons or fatty substances that are in substantially liquid form to solid form, especially for the environmental remediation of surfaces or sites polluted by these hydrocarbons or fatty substances, characterized in that the material to be converted to solid form is brought into contact with a composition heated to the liquid state, comprising, at least in the majority proportion, tallow, and optionally a fluidizing agent, thus obtaining a solid complex material, that is easy to collect, and that can be reprocessed in order to recover the material.

Claims

1. A process to convert substantially liquid hydrocarbons or fatty substances to solid form, for the remediation of surfaces or sites polluted with these hydrocarbons or fatty substances, comprising contacting the matter to be converted to solid form with a composition in the liquid state comprising ovine or bovine tallow at least in majority proportion and optionally a fluidizing agent, thereby obtaining a solid complex material, the liquid state of said composition being obtained by heating said composition to a temperature of at least 45 C., wherein immediately before said contacting, the matter to be solidified is pretreated to improve the distribution of said composition within the matter, said pretreatment comprising sprinkling said matter to be solidified with an acid, the volume of said acid being 10% or lower of the total volume of composition used, said pretreatment being carried out in a zone at a short distance ahead of the zone in which the matter to be solidified is contacted with the composition in liquid form, and wherein said acid is a short-chain organic acid.

2. The process according to claim 1 wherein an excess amount of composition is poured onto the matter to be solidified, said amount being at least two times higher than the amount needed to solidify a quantity of hydrocarbon or fatty substance, the formed solid mixture is collected then heated to a liquid, and the treated mixture is poured onto another quantity of the matter to be solidified, another solid mixture is formed is collected and optionally this operation is renewed one or more times if the mixture last formed is capable, once heated and poured, of solidifying a further quantity of matter to be solidified.

3. The process according to claim 1, wherein the proportion of fluidizing agent is 5% by weight or less.

4. The process according to claim 3, wherein the proportion by volume of said ovine or bovine tallow relative to the total composition is at least 75%.

5. The process according to claim 3, wherein the proportion of fluidizing agent is in the range of 1 to 2% by weight.

6. The process according to claim 1 further comprising the recovering of solid material at ambient temperature from the solid complex material comprising tallow and hydrocarbon or fatty substance obtained using the process according to claim 1, wherein said complex material is heated to softening temperature of the tallow in the material and the material is subjected to pressing against a filter or to centrifugation to separate the liquid hydrocarbon or fatty substance from the softened tallow.

7. The process according to claim 6, wherein said softening temperature is 30 to 38 C.

8. The process according to claim 6, wherein the proportion by volume of said tallow relative to the total composition is at least 90%.

9. The process according to claim 1, wherein the converting of said substantially liquid hydrocarbon or fatty substance material to solid form via pouring of said composition, collecting of said solid complex material thus formed, separation at least of the tallow from the collected hydrocarbons or fatty substances, re-manufacture of said composition from said separated material and pouring of said re-manufactured composition are carried out continuously.

10. The process according to claim 1 wherein said composition is heated at a temperature of 45 to 55 C.

11. The process according to claim 1, wherein the pretreatment further comprises jetting compressed gas onto the matter to be solidified and/or mechanical separating said matter to be solidified.

12. A process to recover solid material at ambient temperature from a solid complex material comprising tallow and hydrocarbon or fatty substance obtained using the process according to claim 1, wherein said complex material is heated to a temperature equal to or higher than the melting point of the tallow in the composition, after which said tallow is separated.

13. A remediation process via solidification according to claim 1 of a substantially liquid hydrocarbon or fatty substance material in a slick on a site, for remediation of this site, wherein an amount of composition comprising tallow and optionally a fluidizing agent, heated to the liquid state, is poured to the slick to bring the composition in contact with the slick at a large number of points or even over the continuity of the treated surface of the slick, the solid complex material thus formed is collected and optionally at least the tallow is separated, by heating, from the hydrocarbons or fatty substances derived from the slick.

14. The process according to claim 13, wherein an amount of composition comprising tallow and optionally a fluidizing agent ranging from 0.05 to 1litre, is poured per slick square metre of hydrocarbon or fatty substance.

Description

(1) Other advantages and characteristics of the invention will become apparent on reading the following description given as a non-limiting example with reference to the appended drawings in which:

(2) FIG. 1 gives a schematic view of the tank of a container to manufacture a composition of the invention, and its separate heating elements.

(3) FIG. 2 gives a schematic view of this tank with its assembled heating elements.

(4) FIG. 3 gives a schematic view of the lid-forming part of this tank.

(5) FIG. 4 gives a schematic view of the container formed by the tank with its lid.

(6) FIG. 5 gives a schematic view of the container provided with a flexible transfer conduit, and separate pour ramp.

(7) FIG. 6 gives a schematic view of the insulating cladding of the tank.

(8) FIG. 7 gives a schematic view of an upper cover with control means.

(9) FIG. 8 gives a schematic view of the heat-insulated assembly.

(10) FIG. 9 gives a schematic view of a nozzle to pour (spray) the composition.

(11) FIG. 10 gives a schematic view of a nozzle ramp.

(12) FIG. 11 gives a schematic view of a nozzle ramp at another height and at another spreading angle.

(13) FIG. 12 gives a schematic view of an associated acid-spraying preparation device.

(14) FIG. 13 is a schematic profile view of a composition pour ramp with float.

(15) FIG. 14 is a schematic perspective view of this ramp that is part of a remediation assembly to clean a hydrocarbon slick on an aquatic site.

(16) FIG. 15 gives a schematic view of a tank of a device to recover the material of the composition.

(17) FIG. 16 gives a schematic view of a lid for this recovery tank.

(18) FIG. 17 gives a schematic view of a container for use of large volumes of composition of the invention.

(19) FIG. 18 gives a schematic view of a collecting net of a device of the invention.

(20) FIG. 19 is a schematic profile view of an improved assembly for continuous remediation of a hydrocarbon slick of large surface area on an aquatic site.

(21) FIG. 20 is a schematic overhead view of this assembly.

(22) FIG. 21 is a schematic perspective view of a device to recover the composition of the invention by pressing.

(23) FIG. 22 is an exploded schematic view of a centrifuge recovery device.

(24) FIG. 23 gives a schematic view of this mounted device.

(25) With reference to FIGS. 1 and 2, it can be seen that the device comprises a tank 1, preferably metallic of cylindrical shape with a bottom part 2 and upper opening 3. To heat a volume of tallow placed in the tank 1, the latter in its lower part is surrounded by an electric heating belt 4 of usual type, with an electric power box 5 also comprising a thermostat. The tank 1 is placed on a bottom support 6, also a heating support, with its power box 7 and thermostat. Means (not represented) can also ensure securing to the bottom support. For devices of large size in particular it is advantageous to provide gas heating for self-sufficient operation but another other form of self-heating may be suitable.

(26) In FIGS. 3 and 4 a lid 8 can be seen of cylindrical shape which can be sealingly positioned by sliding over the top part of the tank 1. This lid 8 has a steel tube 9 bevelled at its lower end 10, which passes through the upper planar part 11 of the lid 8 and leads into a pump 12 fixed thereto and from which there emerges a discharge pipe 13 having a connector end 14.

(27) The lid 8 also carries a spiral agitator 15 extending downwardly parallel to the tube 9 and driven by a motor 16 also fixed to the upper part 11 of the lid. Preferably the motor 16 drives the agitator via a clutch, not illustrated, for mechanical uncoupling should the composition be in solid state or too viscous.

(28) As can be seen in FIG. 5, the connector outlet 14 receives a pressure-resistant flexible tube or conduit 17 along which there extends a heating cable 18 able to be connected to a power source to ensure heating of the tube 17. The assembly formed by the tube 17 and heating cable 18 can also be surrounded by a flexible heat-insulating cladding, not illustrated.

(29) At the other end 19 of tube 17 a tubular pour ramp 20 is connected having a conduit 21 connecting to the flexible tube 17 perpendicular to the ramp itself. The tubular ramp 20 has a plurality of equidistant pour nozzles 22 adapted to pour the hot liquid composition. Preferably the ramp 20 and optionally its central conduit 21 also comprise an electric heating lead or cable, not illustrated, and can optionally be surrounded by a heat-insulating cladding, also not illustrated.

(30) Finally the nozzles 22 are also surrounded by heating means, preferably heating collars.

(31) All these electric heating elements, belts, cables and collars are of usual type and commercially available.

(32) With reference to FIGS. 6 to 8 a heat-insulating jacket 23 can be seen with a bottom part 24 and a hinged semi-cylindrical opening part 25. Once the container formed by the tank 1, its lid and different components are placed inside the enclosure 23, the latter is covered in its upper part with a heat-insulated cover 26 of cylindrical shape with a slit 27 to pass the transfer conduit 17, this cover surmounting the elements carried by the lid 8, such as the pump 12, conduit 13 and agitator motor 16.

(33) Preferably the heat-insulating cover 26 carries a control box 28 for the pump and agitator, this box able to be removably connected via cables and connectors, not illustrated, to corresponding connection means carried by the enclosure lid 8. The cover 26 may also comprise an electric power connector 29 which can be removably connected to electric connection means carried by the lid 8, not illustrated to power the pump 12, motor 16 and optional solenoid valves, not illustrated, for transfer of the liquid composition.

(34) Preferably the enclosure 23 may also comprise an electrical power connector 30 that can be removably connected to the boxes 5 of the heating belt 7 and heating bottom part. This connector 30 may possibly form a box comprising the heat control means.

(35) With reference to FIG. 9 a flat jet nozzle 22 can be seen of usual commercially available type with a screwed portion 32 on the nozzle body 31 allowing adjustment of the spray angle via rotation. A heating collar 33 secured around the nozzle and powered with electric current by a cable 34 allows the nozzle to be kept at the desired temperature.

(36) With reference now to FIGS. 10 and 11. FIG. 10 shows a ramp 20 formed of a metal tube having a plurality of nozzles 22 oriented downwardly and positioned every 20 to 60 cm, for example 30 cm. To solidify a thick slick of hydrocarbon 35, for example 0.5 to 60 even 100 mm thick, flat jet nozzles 22 are provided having a spray angle of between 15 and 30 fed with hot liquid composition at a pressure between 3 and 6 bars, the spray angles overlapping at the impact point on the slick 35. The ramp 20 is carried by one or more supports of adjustable height secured to a vehicle or vessel so as to position the ramp at a height of 30 to 100 cm above the slick 35.

(37) For solidification of a slick 36 less thick e.g. a few tenths of a mm to 1 cm, FIG. 11 shows a ramp 20 having nozzles 22 with a spray angle in the order of 80, these angles overlapping at the slick 36. The ramp may advantageously be positioned at a height of 30 to 50 cm above the slick.

(38) With reference to FIG. 12 a device can be seen to prepare the slick by sprinkling citric acid, comprising a tank 37 of non-heated citric acid, provided with a transfer pump or preferably an air compressor, not illustrated, allowing transfer of the acid under pressure via a flexible conduit 38 towards a ramp 39 shown in profile and having a plurality of nozzles 40 sending very fine jets of acid in downward direction. These nozzles are positioned at intervals of 15 to 30 cm for example, and are supplied at a pressure of between 3 and 6 bars for example. Ramp 39 is secured via one of the securing means 41 to ramp 20 and is height-adjustable independently of ramp 20, for example at a height ranging from 15 cm to 1 m. In addition the acid ramp is preferably also adjustable so that it can be distanced ahead of ramp 20 by a distance ranging from 30 to 60 cm for example.

(39) Therefore ramp 39, parallel to ramp 20, is able to spray onto the polluting slick a curtain of very fine acid jets perforating the slick that is thereby prepared to receive immediately afterwards the sprinkling or spraying of hot liquid composition of the invention.

(40) As a variant, the ramp 39 can be replaced by a ramp of compressed air sending very fine jets in downward direction able to perforate the hydrocarbon slick.

(41) The ramps 20 and associated ramps 39 may be of different length ranging from about ten cm for small-size portable solidification devices up to 6 or 10 m for pollutions of great magnitude. It is also possible to make provision for portable devices only having a single nozzle for the composition, preceded by a short distance by an acid nozzle.

(42) FIGS. 13 and 14 illustrate a ramp 20 of long length e.g. 4 m, formed of a metal tube closed at both ends and having a plurality of equidistant nozzles along its lower edge, this tube carrying a heating cable and preferably heat-insulating cladding from which the nozzles emerge. At these two ends, the ramp 20 is carried at adjustable height by supports e.g. vertical arms 42, themselves secured onto corresponding floats 43.

(43) This assembly is attached in front of the anterior part of a watercraft 44, illustrated in FIGS. 15 and 16, which carries the device to prepare the hot liquid composition with its heat-insulating cladding 23, 26, and is connected to the centre of the tube via a heated, heat-insulated conduit 17. The floats 43, by means of arms 45 and in a position ahead of the ramp 20, may also carry an acid pour ramp 39 having a plurality of fine nozzles, the height of this ramp preferably able to be adjusted independently of ramp 20 and at a distance e.g. 30 to 60 cm in front of the latter in the direction of travel of the craft 44 which pushes this floating assembly e.g. via hinged arms linking the floats 43 to the craft. Ramp 39 is connected by conduit 38 to the pressured acid feed device 37. This ramp 39 may be offset to the rear of ramp 20 when the craft moves in opposite backward direction.

(44) It is not essential for the ramps to be carried by their own floats, but such floats have the advantage of guaranteeing a constant spreading height.

(45) With reference to FIGS. 15 and 16. Recovery of the tallow and solidified polluting liquid can be carried out in a heated tank to liquefy the different materials which then decant and form non-miscible superimposed layers. The pollutant such as liquid hydrocarbon or fatty substance forms a top layer resting on the layer of tallow material solid at ambient temperature, this layer possibly resting on a thin layer of water which could originate from collection of the solid assembly formed using the process of the invention. These layers can then be separated for example using simple aspiration steps. However it is preferred to leave the tank to cool so that said material such as the tallow solidifies, and the overlying liquid layer of pollutant is evacuated for subsequent recovery of the material in solid form.

(46) Advantageously identical elements to those used to manufacture the liquid composition can be used, for example a tank 1 with its heating elements 4 and 6. The tank may also have an outlet tap 46 in its lower part in the event of formation of a thin layer of water. The tank can be closed by a lid 47 similar to lid 8 with or without the agitator 15 and its motor 16 linked by a clutch, the pipe 9 being replaced by a flexible tube 48 to aspirate and evacuate the pollutant.

(47) Preferably the device also comprises cooling means, allowing rapid solidification of the material such as tallow once it has decanted, thereby further facilitating separation thereof. It is possible for example to provide for alternate heating and cooling belts surrounding the tank 1 or interleaved heating and cooling coils with a cold source provided in the base 6 for example.

(48) The re-solidified material can then be evacuated but it is far more preferable to make reuse thereof for a new remediation cycle optionally replacing lid 47 by a lid 8 then heat-insulating the tank so that the material of the composition becomes liquid again, if necessary after addition of the lubricating product.

(49) When the process of the invention is applied to clearing of a slick on an aquatic surface e.g. a river, lake or sea, the recovery or collecting of the solidified complex material floating on the surface can be carried out using any suitable means e.g. a net. The mesh of this net is preferably fairly fine to recover most of the solidified matter whilst allowing good flow-through of water so that material that is substantially water-free can be collected. Preferably the mesh size is between 4 and 10 mm e.g. 5 mm.

(50) With reference to FIG. 17. To simplify the device of the invention it may be advantageous not to use an agitator. The heating tank la intended to heat the composition receives a suction tube 13a fitted with a valve 13b and leading to the suction of a pump 12a which discharges the composition towards a discharge tube 13c fitted with a valve 13d allowing transfer of the hot composition under pressure to the conduit 17 feeding the nozzle ramp. A bypass 13e, fitted with valve 13f, alternatively allows discharge of the composition into the tank 1a, and hence homogenization of the composition during its preparation and storage.

(51) With reference to FIG. 18 a preferred example of a net can be seen comprising a rectangular boom 49 filled with air connected to a similar lower boom 50 but filled with water. The rectangular surface inside each boom has a sheet of netting 51, 52, the two booms being connected on three sides of the rectangle by corresponding net walls, 53, 54, 55, the last long side forming the opening side 57 of the net. A cable or cord 58 can be provided to close the opening of the net on completion of collection, the booms then being either deflated or emptied of water respectively after which the net can be drawn up out of the water and emptied into a tank. For example this cable can be guided along anterior sections of the booms 49 and 50, even along anterior edges of the net sides 52, 53 e.g. under loops. The closed net remaining afloat can also be left on site for recovery by another craft.

(52) With reference to FIGS. 19 and 20 a description is given of a device to implement the process for a hydrocarbon slick of large or very large surface area in an aqueous medium on which conversion of the slick to a solid, collection of the solid complex material thus formed, separation of solid tallow from the hydrocarbon at ambient temperature, re-manufacture of said composition from said separated material and application of said remanufactured composition are continuously performed together with storage or evacuation of the liquid hydrocarbon.

(53) The assembly comprises a craft with two hulls or floats 59 linked by a bridge 60 of catamaran type, the hulls being spaced apart by a distance of 6 m for example, the craft comprising engine means driving one or more propellers immersed at depth to prevent substantial impact on the slick, usual steering and navigation means, and an electric generator unit. This craft, at the front of the bridge 60, carries two ramps 20 and 39 illustrated in FIG. 14, with their floats and adjusted at the desired heights having regard to the type and thickness of the slick, the whole carrying reference number 61 and supplied via their respective conduits carrying general reference number 62. These ramps are connected to the bridge 60 via two hinged arms 63.

(54) The bridge 60 carries a device 64 to manufacture the heated liquid composition, for example of the type described in FIG. 1 to 8 or 17, to feed spray ramp 20 and a device, not illustrated, to feed ramp 39 incorporating a citric acid tank of large volume.

(55) The bridge also carries a device 65 to recover animal fat material namely tallow and solidified liquid pollutant e.g. of the type illustrated in FIGS. 15 and 16, this device able to extract tallow preferably still in liquid form from layer 66 for transfer thereof preferably periodically via conduit 67 to a heated intermediate tank 68 feeding device 64 preferably periodically with already liquid material via conduit 69. The hydrocarbon layer 70 is evacuated via conduit 71 towards a hydrocarbon tank or receiving container 72.

(56) The clumps or solid aggregates of complex material formed by application of the composition of the invention and floating between the two hulls of the craft are collected by collection means 73 and discharged into the tank of the recovery device 65. These collection means may be of various types e.g. a bucket chain of which the buckets, not illustrated, have a bottom grating to allow evacuation of the water collected with the material whilst the material is retained as the buckets are lifted, or simply a slightly angled conveyor belt 74, preferably gridded optionally provided at regular intervals with retaining cross-pieces or simply having on its outer surface sufficient roughness to prevent large blocks or fragments from rolling downwards, the lower end of the belt being immersed to receive the solidified complex material.

(57) These collection means may extend over the entire distance of the bridge between both floats, but it is also possible to use a much narrower collection device preferably positioned in the centre of the bridge 59, making provision for two partly immersed deflectors 75 converging towards the centre and towards the rear to guide the solidified slick towards the collection device 73 in similar manner to a funnel.

(58) At the rear of the craft it is also possible to provide for a net 76 e.g. of the type described for FIG. 18, to collect residual fragments not recovered by the collection device 73. Two deflectors 77 can be provided to centre these fragments in the direction of the net 76.

(59) Finally, it is also possible to make provision for two outer lateral deflectors 78 to guarantee that the non-treated parts of the polluting slick adjacent to the outer side edges of the floats are not directed towards the net 76.

(60) The craft also comprises engine means with one or more propellers immersed several metres deep, steering means, powering means preferably electric to drive the different mobile devices in particular the circuit pumps, agitation means, collection device and in general all useful accessories. For heating of the tanks it is preferable to use gas heating means.

(61) It is therefore possible with a reasonable amount of material, namely tallow, to treat slicks extending over considerable surface areas in the event of major pollutions. It may then be preferred to perform the preparation step of the slick using jets of compressed air and/or mechanical blades to avoid too much acid consumption bearing in mind that for fairly fluid or scarcely thick hydrocarbon pollutions the composition of the invention can be applied directly without preparation of the slick. The amount of composition to be applied to the slick may generally be 0.05 a 0.25 litre of composition per 1 square metre of slick for pollution of an aqueous surface such as river, lake or sea.

(62) With reference to FIG. 21 showing a tallow recovery device by pressing the collected complex material of tallow and solidified hydrocarbon. It comprises a parallelepiped tank 79 in resistant material e.g. steel the bottom 80 of which rests on a base 81 and the top part is open. The tank 79 at the bottom is provided with a drain pipe 82 having a valve (not illustrated). The two long vertical surfaces of the tank on their inner side have two ridges 83 parallel to the bottom. These ridges can support the frame of a very fine wire mesh filter 84 that slides into position via a side opening 85 onto the ridges 83. Preferably a seal plate 85 slides underneath the filter 84, this plate possibly also being withdrawn when the filter is in place in the tank 79. A compression plate 86 can be placed in the tank via its open top and moved sealingly downwards by means of sealing liners (not illustrated) arranged on its four edges. The base carries a motor device 87 e.g. a jack cylinder carrying an arm 88 used to push the compression plate 86 downwards.

(63) When the filter 84 is positioned in the tank 79 with the underlying seal plate 85, a mass of solid complex material of tallow and hydrocarbon is placed in the tank above the filter, the compression plate 86 in the tank is brought to above this mass and the mass is heated to softening temperature e.g. 37 C. Plate 85 is removed and the cylinder 87 is actuated to push plate 86 downwards under strong pressure. The hydrocarbon is seen to flows progressively through the filter into the bottom of the tank 79 where it can be withdrawn via conduit 82. On completion of compression, there remains a cake of tallow above the filter 84 containing less than 1% hydrocarbon. This cake is removed either mechanically or by heating the tank to above 48 C. to liquefy the tallow that can then be drawn off e.g. by passing through the filters 84 and evacuating via pipe 82. The recovered tallow can be reused to solidify and collect a further quantity of polluting hydrocarbon or fatty substance.

(64) With reference to FIGS. 22 and 23 a centrifuge can be seen to recover a tallow composition of the invention. On a base 89 it comprises a lower fixed cylindrical tank 90 on which an upper fixed cylindrical tank can be arranged the bottom of which is formed by a removable circular plate 92 provided with a central passageway 93 extended by a short central duct 94 provided with a draining valve 95. The device comprises a rotor 96 forming a cylindrical basket preferably having multiple perforations both in the bottom part and in its cylindrical surface. This rotor is able to rotate inside the tank 91 about a vertical axis common to the assembly being guided, as is usual, by ball bearings (not illustrated) inserted between the bottom of the rotor and the upper surface of the plate 92. On the top surface of the rotor 96 there is removably attached a toothed disk 97 meshing with a toothed wheel 98 driven by a motor assembly 99 secured to the base 89.

(65) A mass of solid complex material is placed in the rotor 96, the toothed disk 97 is attached to the rotor and the rotor is placed in the tank 96 attached to plate 92. The mass is heated to softening point between 30 and 38 C., and the rotor is rotated in the tank e.g. at 300 rpm, whilst opening valve 95. It is ascertained that the mass of material in the rotor 96 comes to lie against the inner surface of the cylindrical wall of the rotor and even passes through the rotor towards the inner cylindrical wall of the tank 91, opening up a free central volume in the rotor, whilst the hydrocarbon is extracted from the mass and flows centrally downwards through the central perforations in the bottom of the rotor and through duct 94 to be recovered in the lower tank 90 from which it can be drawn off via a pipe not illustrated. On completion of centrifugation, the mass of recovered tallow is found in the rotor and tank 91, the recovered mass containing a small amount of hydrocarbon. This mass is recovered either mechanically or preferably by heating the assembly to above the tallow melting point allowing liquid tallow to be received in the bottom tank 90 after draining the hydrocarbon.

(66) As examples, the processes of filtering under pressure and centrifugation each allowed tallow containing less than 1% of pollutant to be recovered from materials comprising spent engine oil of density 0.855, milk of density 1.050 or diesel oil of density 0.850.