PRODUCTION

Technical Field

The present invention relates to a coalescing filter for water/oil disperse system separation, a coalescing medium for coalescing filter and a method of coalescing medium production, and in particular to water cleaning from hydrocarbons using coalescing medium manufactured from scrap of fabricated rubber products, preferably motor tires.

Background Art

The environmental problem of oil collecting from water surface is known to promote another topical environmental problem, namely, recovery of scrap of fabricated rubber products, particularly, motor tires, through manufacturing powdered sorbent thereof (GB 1384217 (A), NITTAN CO LTD, 19.02.1975). Crumb rubber sorbent for water surface cleaning is featured by high adsorption capacity for crude oil and oil products, reliable extraction of swollen crumb rubber in crude oil and oil products, possibility of oil spill containment, and ensuring coastline protection. The sorbent is distributed over water surface and collected following oil products adsorption. This material may be employed for mixing with asphalt in road construction.

Similar solutions are described in later patent publications EP 1279715 Al, KAHL AMANDUS MASCHF, 29.01.2003. Research data are published in literature (e.g. T.F.Tarasova, D.I.Chapalda, Yu.R.Abdrachimov, "Crumb rubber application as an oil spill sorbent; Vestnik OGU, No. 4, April 2007, pp. 151-157; K.S.Shikhaliev, M.Ya. Abdullayeva, "Waste motor tires-based sorbent for water surface cleaning from crude oil and refined products", Journ. "Of Eurasian Union of Scientists", v. 6-2, 2016, pp. 80-81).

Separator filters employing coalescing materials of various composition and structure are also known to be highly efficient in water cleaning from oil sludge. For example, patent RU 2104736, 20.02.1998 describes oleophilic fibrous material, whereas RU2181068, 10.04.2002 describes a filter using granulated coalescing one. A bed constituting volumetrically corrugated polymer fiber non-woven fabric with hydrophobic surface and a layer of hydrophilic super-fine fiber is described in the patent RU2361661 C2, 20.07.2009. Multilayer coalescing filters are described in GB2422148 (A) - Oil/water separation apparatus, 19.07.2006, and in the RU78436 Ul, 27.11.2008. The prior art shows that there is only one product of scrap of fabricated rubber products recovery is being employed as a sorbent for oil sludge waters, that is, crumb rubber; however, it is not expedient for utilization as a filtering medium in said coalescing separators, primarily due to the high hydraulic resistance of such fine-grain loose medium.

A multitude of various mechanical methods and apparatus is described for recovery of fabricated rubber products that do not relate to crumb rubber production but at the same time not employed as filter active media. These are, first of all, slicing (see., e.g., RU2429122 CI, 20.09.2011), abrasive finishing (DE19506964 Al, 27.06.1996), drilling (RU2605128 CI, 20.12.2016), producing a continuous ribbon out of the tire (RU2337001 CI, 27.10.2008). This means that in tire recovery, traditional techniques and methods known in the material processing industry are employed, which are merely upgraded.

The prior art closest in the purpose and operational principle is the coalescing filter described in DE3902155 Al, 26.07.1990, wherein the coalescing chamber is filled with loose packing of polyolefin (polyethylene) chips of curved ribbon-like shape of 0.01- 0.4 mm thickness, 22-20 mm width, and 4-60 mm length. Such material enables reducing hydraulic resistance of the filter and containment of the sorbent in the coalescence area; however, it has its drawbacks. Polyolefins poorly accumulate oil, rather only providing drops coalescence, which requires a decanter downstream the filter. Besides, polyolefins are rather rigid and are not fit for oil squeezing, as they would get compressed and would be not suitable for further utilization.

Disclosure of Invention

An object of the present invention is to provide a coalescing filter and coalescing medium for the coalescing filter having an improved efficiency.

Another object of the present invention is to provide a method for producing a new coalescing medium from rubber product scrap, preferably, motor tires, and other rubber scrap types, which coalescing medium is a highly efficient sorbent of oil products and may be employed in streamline filters.

A coalescing filter for water/oil disperse system separation comprises a chamber with an inlet, an outlet, and a chamber cavity filled with at least one coalescing medium, wherein the coalescing medium comprises a product of mechanical machining of synthetic cord-based rubber products into flow spiral chips and/or flow strip-shaped chips having longitudinal surface roughness.

The longitudinal surface roughness of the chips may have medium size in the range of 0.1 to 20 μηι.

The flow spiral chips and/or the flow strip-shaped chips may have through- perforation of the surface.

The flow strip-shaped chips may have thickness in the range of 0.05 mm to 5 mm, width in the range of 0.05 mm to 20 mm, spiral radius in the range of 5 mm to 30 mm and length at least 100 mm.

The strip-shaped chips may have thickness in the range of 0.05 mm to 5 mm, width in the range of 0.05 mm to 20 mm and length at least 100 mm.

Synthetic cord-based rubber products may be selected from the group comprising worn motor tires, tire casings, conveyor belts, scrap rubber hoses, or drive belts.

Mechanical machining may be selected from the group comprising lathe turning, drilling, shaping, and milling.

The chips may be subjected to silicon-organic or fluoro-organic hydrophobization. The method of production of coalescing medium through mechanical machining of synthetic cord-based rubber products comprises the following operations: formation of a compressed packet of adjacent individual rubber products; providing mutual rotating and translational motion of a cutting tool with respect to said packet at parameters of said mutual rotating and translational motion of a cutting tool with respect to said packet selected basing on the condition of obtaining of flow spiral chip and/or flow strip-shaped chip providing longitudinal chip surface roughness with average size of 0.1 to 20 μηι.

The method may be characterized in that motor tires and tire casings are cut in the diametrical plane, stacked to form a packet, tensioned and fixed on the rotation axis between the two fixing discs.

The method may be characterized in that conveyor belts, scrap rubber hoses, drive belts are rolled into a compact cylinder to form a packet, tensioned and fixed on the rotation axis between the two fixing discs.

The technical result is improvement of the efficiency of oil sludge separation due to combination of high specific surface with high hydrodynamic permeability. Loose packing of rubber chips provides for preservation of filter permeability for water, even at high sorbent saturation with oil, and the peculiarity of the material consisting in chip surface self-perforation in the locations of cord filaments cutting enables generating of an additional growth of sorbent surface. Due to rubber deformation and microbreaking in the process of cutting, as well as due to spontaneous separation of cord residues in the course of mechanical machining, an additional porosity arises in the chips, which increases the area of sorbent to medium contact.

Real oil sludges usually contain mechanical admixtures, such as sand, soil, clay, and certain other structures. It has been experimentally established that the coalescing filter for water/oil disperse system, according to the present invention, allows to separate mechanical admixtures from oil component. The oil component is deposited on the surface of chip filter packing and it may be further removed together with the chips in the form of oil tar balls, leaving mechanical admixtures in the water phase.

An important parameter of the scrap tires chip material is the contact angle of wetting; the higher is this angle, the higher is the rubber hydrophobicity, hence, its capability to bind oil, oil products, and fats. It has been experimentally shown that the contact wetting angle of the produced chips constitutes 116° - 135°, whereas for original smooth motor tire rubber this parameter is within the range of 100° - 104°. Approximately the same angle range (about 105°) has polyolefin-polypropylene. Therefore, it follows from these data that smooth rubber binds oil worse than the polypropylene, while the claimed chips provide a drastic increase of the oil sorption capability as well as oriented flow of oil drops stuck to a chip along chip length. This entails even oil distribution along chip length and prevents formation of oil slags impeding the flow of water being cleaned through the filter.

The rubber sorbent swells in oil products, so it adsorbs up to 4-7 kg of oil per 1 kg of rubber; hence, it does not require additional decanter. At normal conditions the rubber is in elastic state, which enables squeezing the saturated sorbent to separate oil products.

Besides, the sorbent saturated with oil may be employed as an additive for road pavement, whereas polyolefms cannot be used for this purpose. The chips provide an additional reinforcing of the asphalt, which strengthens the latter. When using said oil sorbent for water surface cleaning from oil contaminants, the sorbent capacity is the same as that of crumb rubber. However, rubber cutting into chips may prove to be more technological than cutting into crumb rubber, so specific cost per water surface unit cleaning may be reduced. The additional technical result consists in utilization of environmentally harmful scrap tires through traditional mechanical machining without pyrolysis. The obtained material may be used as a basis for sorbents, as packing and waterproofing material, as a grass paver, soil protection nets and ecoparking material. Brief Description of Drawings

Fig. 1 is a flowchart of the coalescing filter;

Fig. 2 is a photograph of the structure of coalescing medium obtained from motor tires protector rubber;

Fig. 3 is a flowchart of the apparatus for tire processing into flow chips;

Fig. 4 is a photograph of the experiment in tire processing into flow chips on the lathe.

Modes for Carrying Out the Invention

The flowchart of the coalescing filter for water/oil emulsions is shown in Fig. 1. The filter comprises a chamber 10, the chamber cavity 11 of which is connected with pipes 12, 14, 16, 18, the number and purpose of which, input and output ones, may differ depending on the hook-up. The chamber cavity 11 is filled with at least one coalescing medium 20 confined between meshes 22;

Fig. 2 is a photograph of the coalescing medium 20 constituting the flow chips obtained from motor tire protector rubber;

Fig. 3 shows a flowchart of the apparatus for tire processing into the filtering material, flow spiral chips and/or flow strip-shaped chips, wherein: packet 30 of processed tires 31, fixing discs 32 providing fixing and tensioning of the packet 30, reel 33, rotation axis 34, lathe rotation direction 35, lathe cutter 36, cutting direction 38.

Prior to cutting of rubber products into flow chips, the former ones are subjected to preliminary handling. For example, sidewalls and treads of tires can be processed separately. There are presently commercially available specialized machine tools for such preliminary handling, cutting off flat sidewalls from the tread, and other machine tools that tear off metal annular frame from the tire. The nature of preliminary handling depends on particular rubber products to be processed and the machine tool available for further processing. Scrap conveyor belts, for example, are cut in such a manner that allows making a packet through laminar reeling. Car tire treads is cut across in one place so that it looses its stiffness and unwinds in a wide thick ribbon.

Cutting may be performed within the rubber product packet temperatures in the range of -196°C to +250°C. At lower temperatures cutting may be performed at higher rpm.

Following the sorption of oil products from water, soil, oil-spilled sand to be cleaned, or following decomposition of refinery sludge, the chip sorbent becomes saturated with hydrocarbons. These chips may be reclaimed by mechanical squeezing, ultrasonic irradiation, microwave processing or extraction. Due to the rubber nature of the substrate, it is feasible not to reclaim the product saturated with hydrocarbons, but rather use it directly as a bitumen component of asphalt. Another possible option of utilization of the sorbent saturated with oil products is petrochemical processing into light hydrocarbons through thermal or catalytical cracking or coking. Such petrochemical processing is possible without separation of the rubber sorbent, as rubber is also a hydrocarbon.

Oil sorption properties of chips may be additionally enhanced through hydrophobization of the chip surface. For example, the studies showed that treating with liquid or gaseous silicon-organic hydrophobic agents enables increasing the contact wetting angle by 15 - 18°. Treating of the chips with liquid fluoro-organic hydrophobic agents enables increasing of the contact wetting angle by 21° - 30° with respect to untreated chips.

Example 1. Obtaining flow spiral chips and/or strip-shaped chips from motor tire casings.

The feedstock rubber products used were car tire casings (tires 31 in Fig. 3) of unknown vehicles with diameter 16" and synthetic filament cord. The tires were cut in the diametrical plane, and then the obtained halves are stacked forming the packet 30. The assembled packet 30 is tensioned and fixed between 0.6 m diameter two uniaxial discs 32 with treaded studs with nuts and washers (conventionally not shown) on the central axis 34. The obtained packet 30 is mounted in the 1K20 lathe chuck (see Fig. 4). Machining was performed with an R65M high-speed steel flat cutter at varying traverse rates and rotation directions at ca. 200 rpm. After grinding off tread contact layer and machining rate selection, the tire was reprocessed into flow spiral chips and/or flow strip- shaped chips. The machining rate was selected so that to provide high-length chips of not less than 100 mm length with 0.05 - 5 mm thickness, 0.05 - 20 mm width, 5 - 30 mm spiral radius. It was discovered in the course of tests that a lengthy fragment of the chip obtained may comprise both strip-shaped and spiral structures, which in general does not considerably effect its pronounced oil sorption properties. The reel 33 serves for preliminary winding of lengthy products, such as conveyor belts, scrap rubber hoses or drive belts.

Fig. 2 shows a photograph of flow chip actually obtained: the chip bundle consists of several fragments of various lengths, it has total length 380 cm, 3 to 6 mm width, 80 to 200 μηα thickness, 0.3 - 0.5 mm cord filament holes with about 10 holes per 10 cm length. Average notch-shaped longitudinal roughness along chip length due to machining with a cutter is 5 to 20 μηι along bundle length.

Chips 20 was used to fill the chamber cavity 11 of the filter shown as a flowchart in Fig. 1 employed for filter sorption features testing. The volume of the cavity filled with the sorbent was 5 dm ³ , the mass of the sorbent was 850 g, filled density 170 g/dm ³ .

The model test object for filter testing was oil-contaminated water from Krasny Bor landfill in the amount of 5 1. The time of travel under gravity of said oil-contaminated water volume through the filter was 4.5 minutes. Content of hydrocarbons in water following cleaning was less than 50 ppb (determined by IR-spectrometry in an extract with carbon tetrachloride).

The results obtained testify to the fact that guaranteed roughness of thin rubber chips surfaces due to oriented grooves improves oil sorption properties, probably due to emergence of the so-called super-hydrophobic effect.

Example 2. Chips chemical treating for increasing hydrophobicity and enhancing of sorption capacity.

2.1. Treating of the chips with liquid silicon-organic hydrophobic agent. 2.0 g of 136-41 liquid silicon-organic hydrophobic agent (according to GOST 10834-76) were added to 100 g of 80 μm-thickness chips. The components were mixed in a horizontally rotating flask for 15 min. Such treating led to contact angle of wetting increasing by 17° with respect to untreated chips.

2.2. Treating of the chips with liquid fluoro-organic hydrophobic agent. 2 g of polyhexafluoropropylene dissolved in 10 ml of Carbogal were added to 100 g of 80 μ ^η ι- thickness chips. The components were mixed in a horizontally rotating flask for 15min. Then said chips are heated in a baking oven at 110°C for 2 hours. This results in increasing of the contact wetting angle by 21° - 30° with respect to untreated chips.

2.3. Treating of the chips with gaseous silicon-organic hydrophobic agent. 100 g of 80 μ ^η ι-thickness chips are placed into a desiccator containing 5 ml of trimethylchlorosilane and kept there for several hours at temperature about 100°C. This results in increasmg of the contact wetting angle by 18° with respect to untreated chips. It indicates that hydrophobic properties of the sorbent and its capacity to collect oil from water are increased. Results of the studies conducted with IR spectroscopy methods show that after the cleaning of strongly contaminated water with the claimed oil sorbent the residual content of hydrocarbons is less than 1 ppm. This is also confirmed by the fact that aliphatic hydrocarbons are not detected at all following cleaning with the claimed oil sorbent. The capacity of the sorbent in oil products is 4 to 7 kg of oil per 1 kg of sorbent, which is comparable with the best commercial sorbents.

Therefore, the product of synthetic cord-based rubber products into flow spiral chips and/or flow strip-shaped chips having longitudinal chip surface roughness and claimed parameters enables combining of high sorption characteristics and high specific surface (up to 500 sq.m per lg) with the ability to be confined with grids and meshes with 0.1- 10 cm mesh sizes, which makes this product a promising basis for ion-exchangers and substrates for ferments and micro-organisms.

The invention may be implemented using the known techniques. The knowledge of the present application regarding its embodiments shall not be deemed as limiting other individual ways of embodiment of the claimed invention staying within the confines of information disclosure in the present invention that shall be evident for a person skilled in the art.