EP4663724A1

EP4663724A1 - Process for the regeneration of fatty waste

Info

Publication number: EP4663724A1
Application number: EP24425027.0A
Authority: EP
Inventors: Giuseppe Magnone; Francesco NEGRI; Francesco Gallo
Original assignee: Itelyum Regeneration SpA
Current assignee: Itelyum Regeneration SpA
Priority date: 2024-06-10
Filing date: 2024-06-10
Publication date: 2025-12-17

Abstract

A process for the regeneration of waste oils is disclosed, including three different feeds, namely a) UCO (used cooking oils)/RUCO (regenerated used cooking oils); b) oils having biological origin, separated from mineral oils under regeneration; and c) solvents and fuels having biological origin. Feed c) is the product of treatments of feeds a) and b) and the three feeds are treated in parallel.

Description

This invention refers to a process for the regeneration of fatty waste, so as to be able to recover valuable chemicals, like biosolvents, biolubricants and/or biofuels.
The use of lubricants of any kind is very widespread and related to many fields of technology, in particular of mechanics. Lubricants allow the mutual sliding of moving parts, lowering friction, reducing overheating and sintering, preventing gripping and slowing down wearing. During the use, the heat produced through sliding triggers some reactions, like cleavage, cracking, hydrogenation, de-hydration amd so on, so that the composition of the lubricants changes over time and its properties are more or less gradually impaired. After a certain use, lubricants contain polymers, metal particles, carbon black and other matters which reduce the lubrication and can speed up the wearing and damages of the mechanical parts. Therefore, the replacement of used oil with a fresh one is required; this is normally done periodically.
Waste lubricants are pollutants for water, soil and sometimes even air. Therefore, they should be disposed of carefully, avoiding spreading them. Since a few decades, waste oil regeneration has been taking place, with the production of bases for fresh lubricants. The Applicant is particularly active in this field and has filed several patents on the subject, resulting in the increase of the percentage of recovered lubricants, in the reduction of the amount dispersed in water and soil and a lower consumption of oi in the production of lubricants, with a dramatic economical and ecological advantage.
Oils from biological sources, especially oils and fats coming from plant sources, are used for cooking, especially for frying. Also such oils should be disposed of carefully after their use, since, although theey normally are non toxic, however they tend to build up in the environment and in sewage. In sewage, they can create masses relatively bulky, which can lead even to pipe explosions, with the consequent spreading of wastewater around, which can be negative for health and expensive for repairing works. Therefore, some reuse of waste cooking oils is also important.
In this way, cooking oils, after their use, have been transformed into biofuel, with the achievement of a reduction of oil used in preparation of fuel. Sometimes, oils from plant sources have been used as lubricants, although they normally are less performing than mineral oils. This kind of lubricants is herein referred to as biolubricants. Also, these biolubricants need to be somehow disposed of.
Waste oils from plant origin are also being regenerated. Sometimes, waste oils, containing mainly mineral oils, collected for regeneration contain non negligible amounts of plant oils, which are a sort of pollutant for mineral oils, and which impair there properties.
Recently, the Applicant has dealt also with oils from plant sources and has filed some patents dealing with such disposal.
Since biolubricants and oils of plant origin are normally esters of carboxylic acids, while mineral oils are mostly hydrocarbons, different kind of process steps are to be used and the two kinds of lubricants should be carefully separated, in order to have performing lubricants, without undesired contaminants.
Since organic esters are polar substances, a polar solvent is able to selectively extract them from the lubricant mixture. Hydrolysis and esterification take normally place, in order to get fresh biolubricants.
In particular, with its European Patent application No. 23425054.6 , the Applicant has developed a process for the production of biolubricants from waste materials, wherein said waste materials are waste biolubricants, UCO, RUCO and a biological fraction of waste lubricants. The biological fraction of waste lubricants is made up by biolubricants, used las lubricants and collected as a waste together with the usual mineral lubricants. Two lines are combined for a subsequent reaction after two separate preliminary treatments, wherein the first line brings waste biolubricants, UCO and RUCO which have been processed and the second line brings a biological fraction of lubricants separated from waste lubricants. The biological fraction of waste lubricants is got through a pre-flash step of waste lubricants and a subsequent step in a decanter, from which such biological fraction is taken from the bottom and the product of hydrolysis is split into two flows, an aqueous phase, containing raw glycerine, and an oily phase, mainly containing fatty acids. According to that patent, bitumen coming from distillation residue of a purification step of product coming from a plate distillation column undergoes a process for the enhancement of the organic molecules, wherein such residue is dissolved in an apolar solvent, the obtained solution is stirred, then is filtered off and/or centrifuged to separate catalyst and a raw material for dyes. Although this process leads to products exhibiting a good quality, sometimes the efficiency of the process is relatively low and leads to a poor overall productivity.
Problem of this invention is to regenerate different kinds of used oils/fats in a single, combined plant, with a very high efficiency and throughput, overcoming the mentioned drawbacks. This goal is achieved through a process for the regeneration of fatty waste, including three different feeds, namely a) UCO (used cooking oils)/RUCO (regenerated used cooking oils); b) oils having biological origin, separated from mineral oils under regeneration; and c) solvents and fuels having biological origin, characterised in that feed c) is the product of treatments of feeds a) and b) and in that the three feeds are treated in parallel. Sub-claims disclose preferred features of the invention.
According to an embodiment, oils fed in b) are taken from different fractions of a process for the regeneration of waste, mineral oils.
According to an embodiment, each fraction of a process for the regeneration of mineral oils is processed at a time.
According to an embodiment, the feed c) is treated any time with an alcohol, which is chosen in order to tailor the viscosity of the end product. Namely, a treatment is performed with the feed c) and an alcohol, then the same feed c) undergoes a treatment with a second alcohol and so on.
According to an embodiment, the feed a) contain also animal and/or plant fats.
According to an embodiment, the waste oils fed in a) and b) are previously transesterified with methanol and are fed through the feed c) as methyl esters.
According to an embodiment, the feed a) is reacted in the presence of a strong base as catalyst. Preferably, the strong base is KOH.
According to an embodiment, the feed b) is mixed with methanol and water.
According to an embodiment, the feed c) is reacted with an alcohol or a polyalcohol, water and a catalyst. Preferably the catalyst is a metal methoxide. Preferably, said metal methoxide is sodium methoxide.
According to an embodiment, the transesterification of the feed a) with methanol takes place in a CSTR reactor. Preferably, the CSTR is operated under room pressure under methanol reflux.
According to an embodiment, the transesterification of the feed a) with methanol takes place in a number of CSTR reactors, operating in parallel or in series.
According to a preferred embodiment, the transesterification of the feed a) with methanol takes place under room pressure, at the saturation temperature of methanol (around 65 °C) for 3 to 6 hours.
According to an embodiment, glycerine obtained as a byproduct in the transesterification of feed a) is separated from the main product and purified through distillation.
According to a preferred embodiment, the main product is purified through a distillation step. Preferably, the distillation step takes place under a head pressure of 133-400 Pa and a tail pressure of 1,066-1,333 Pa, at a bottom temperature of 200-350 °C, preferably 250-300 °C.
According to an embodiment, oils having biological origin, separated from mineral oils under regeneration are transesterified with methanol.
According to an embodiment, oils having biological origin, separated from mineral oils under regeneration, transesterified with methanol, are separated from mineral oils and washed with water.
According to an embodiment, the treatment of feed c) with each alcohol is carried out under a pressure of 1,300-13,350 Pa, at a temperature of 250-350 °C, preferably 280-320 °C, for 8-12 hours.
According to an embodiment, alcohols used for the transesterification exhibit a molecular weight higher than the one of methanol.
According to an embodiment, unreacted biosolvents and/or biofuels coming from the treatment of feed c) are removed by steam stripping.
According to an embodiment, biolubricants produced from the treatment of feed c) are dehydrated.
According to an embodiment, the dehydration of biolubricants takes place under a pressure of 13,300-40,000 Pa, at a temperature of 150-250 °C.
According to an embodiment, the dehydration of biolubricants is carried out in a unit chosen from the group comprising: a vacuum drying column, a membrane, adsorbing beds.
According to an embodiment, adipic acid is added as a co-reactant to the transesterification step of the feed c), in order to increase the viscosity of the obtained biolubricants.
According to an embodiment, the transesterification is carried out choosing a terpenic alcohol as the alcohol. Preferably, such a terpenic alcohol is chosen from the group comprising: L-menthol, geraniol, citronellol, nerolidol, linalol.
Further features and advantages of this invention are anyway more apparent when reading the following detailed description of a preferred embodiment, which is given as an example only, with non-limiting purposes, and which is illustrated in the annexed drawings, wherein:

fig. 1 is a general, block diagram of the process according to this invention;
fig. 2 is a flow chart of the part of the process referred to the regeneration of UCO/RUCO and similar wastes;
fig. 3 is a flow chart of the part of the process referred to regeneration of the oils having biological origin which are mixed together with mineral oils in a waste;
fig. 4 is a flow chart of a process for the regeneration of waste lubricants; and
fig. 5 is a flow chart of the part of the process referred to the regeneration of biolubricants.

Wastes to be regenerated through the inventive process can include UCO, RUCO, animal and plant fatty waste from the processing of fatty matters, used lubricants of biological origin, biological part of waste lubricants.
The overall flow chart of the inventive process is reported in fig. 1.
The process according to this invention is made up by three components: a treatment of used cooking oils and regenerated cooking oils (UCO and RUCO) 1, a treatment of the biological content coming from the regeneration of waste oils 2 (namely a mixture of waste mineral and biological lubricants) and the production of biolubricants 3. The components 1 to 3 of the overall process are managed in parallel and they are synergistic.
Pipes 4 and 5 for reactants are fed, together with a catalyst fed through a pipe 6, to the treatment 1. Products of the treatment 1 make up flows brought by pipes 7, 8 and 9. While flows brought by pipes 7 and 8 are stocked for sale, flow 9 is split into stock 10 and a flow 11.
This treatment of used cooking oils and regenerated cooking oils (UCO and RUCO) 1, possibly together with animal and plant fatty wastes as well as used lubricants of biological origin, is detailed in fig. 2. Pipes 4 to 6 feed a reactor 12, from which an outlet 13 exits and feeds a second reactor 14. The reactor 12 has also a second outlet 15. Also, the reactor 14 has two outlets, 16 and 17. The flow of the outlet 16 merges into the flow of the outlet 15 and the resulting flow 18 is recycled into the flow brought by the pipe 5, after a makeup 19 and after merging with another flow 20. The reactors 12 and 14 can be CSTR's, but tubular reactors are per se not excluded.
The outlet 17 feeds a decanter 21, from where two outlets, 22 and 23, exit.
The outlet 22 feeds a distillation unit 24, from which a head fraction 25 and a bottom fraction 26 are separated. The bottom fraction 26 feeds, after heating in 27, a plate distillation column 28, separating three product streams, brought by pipes 7, 8 and 29.
Also, the outlet 23 feeds a distillation unit, in this case distillation unit 30, separating the liquid into two outlets. The contents of flow 31 merges with the contents of flow 25 and the resulting flow feeds a distillation column 33, leading to two flows 34 and 35.
The flow 35 feeds another distillation unit 36, leading to a waste 37 and to another flow 38 which splits into a purge 39 and the flow 20.
The flow 32 feeds, after heating in 40, a plate distillation column 41, leading to the flow and to outlets 42 and 43.
The treatment of the biological content coming from the regeneration of waste oils 2 is illustrated in fig. 3.
Reactants are fed to the treatment 2 from inlets 44 and 45. They are fed to a mixer 47, from where an outlet 48 exits and feeds a decanter 49. The decanter 49 allows to separate two streams: a tube 50 removes light components and a tube 51 the heavy components.
The tube 50 leads the light fraction to a mixer 52, where the extracted phase is mixed with water coming from the tube 46a. An outlet 53 brings the mixture to a decanter 54, where two phases separate. The heavy fraction leaves the decanter 54 through a pipe 55 and feeds a distillation packed column 56. The bottom of the column 56 is wasted through the outlet 57. The head of the column 56 exits through a tube 58 and is split into two flows: one is the vent 59 and the other one is the flow 45, where a makeup 60 is added. The light fraction exits through the pipe 61, which is shown in two separate ways in fig. 1 (61a and 61b, respectively).
Turning back to the tube 51, the latter feeds a mixer 62, where water is added from the inlet 46b (tubes 46a and 46b make up the inlet 46 in fig. 1). An outlet 63 feeds the mixture to a decanter 64, where two phases separate. Tubes 65 and 66 collect the contents of the two phases.
The production of biolubricants 3 is illustrated in fig. 5.
The waste oils fed in the previous treatments 1 and 2 are previously transesterified with methanol and are fed through the feed c) as methyl esters.
Products coming from treatments 1 and 2 as flows 9 and 61 join together and are fed, together with a catalyst 68, other reactants 69 (so called co-reactants) and water 70 to a reactor 71, from which a vent 72 and another flow 73 exit. The tube 73 feeds a mixer 74, where also a tube 75 brings water. A mixture leaves the mixer 74 through a pipe 76, which in turn feeds a decanter 77, where two layers separate. The heavy layer is vented through a pipe 78, while the useful light layer is brought by a pipe 79 to a stripping column 80, fed also with steam by a pipe 81. The unreacted reactants leave the stripping column 80 through a pipe 82 and are recycled to the product 9. The useful product is removed through a pipe 83 and fed to a dehydrating column 84 with a vent 85 and a product collection 86.
The process according to this invention is now described, with reference to the plant scheme depicted above.
First of all, the treatment of used cooking oils 1 is described. Used cooking oils and related raw materials (see above) are fed from the pipe 4 into the reactor 12. Normally, this feed includes UCO, RUCO and possibly animal and/or plant fats. The reactor 12 receives also methanol from the pipe 5 and a strong base from the pipe 6, which is useful as a catalyst. Strong bases fed through the pipe 6 can be of any kind and NaOH, KOH and CaO are the preferred ones, particularly KOH, because of the wide availability and the low cost. The catalyst can be solid or a solution of the base.
The reaction, which is a transesterification, can take place under pressure or under room pressure, at a temperature in the range 30 to 120 °C.
The mixture produced in the reactor 12 exits through the outlet 13 and feeds another reactor 14, while unreacted methanol exits through the pipe 15. Methanol which has not reacted in the reactor 14 is also fed to the pipe 15 through the pipe 16 and all this methanol is recycled through the pipe 18 to the pipe 5, so saving part of the costs for reactants.
The product from the reactor 14 is fed, through a pipe 17, to the decanter 21. A centrifugal separator can be used instead of the decanter 21, leading to a faster separation.
The pipe 22 brings the heavier layer separated in the decanter 21 to the distillation step 24. The bottom of the distillation is sent through the pipe 26 and a heater 27 to the plate distillation column 28, operating under room pressure and at 65-100 °C, from where three products are separated: a vent 29, venting light substances, bitumen through the pipe 7, which is a marketable by-product and pure glycerine 8, which is also a marketable by-product of this process and which has a relatively high value for pharmaceutical and cosmetic productions. Methanol leaves the distillation step 24 from the pipe 25.
The pipe 23 brings the lighter layer separated in the decanter 21 to the distillation unit 30. Methanol is separated as head and leaves the distillation step 30 through the pipe 31 and reaches the distillation column 33, from where light products are vented in 34 and the bottom is sent through the pipe 35 to the distillation unit 36, operating at 65 °C. The bottom from the distillation unit 36 is wastewater, which is discharged in 37, while the head is methanol, which leaves the distillation unit 36 from the pipe 38 and is partially purged in 39 and partially recycled through the pipe 20 to the flow brought by the pipe 5, after having merged with makeup methanol from the pipe 19. In this way, an important part of the costs for reactant is advantageously recovered.
The bottom in the distillation unit 30 is brought from the pipe 32, through a heater 40, to the plate distillation column 41. Light substances are vented in 43, while biosolvents are transported from the pipe 9 and bitumen is removed by the pipe 42. Biosolvents collected from 9 can be either sent to the production 3 or collected as marketable products; in this case, biosolvents can be used either as solvents or as fuels (like biodiesel).
Secondly, the treatment of the biological content coming from the regeneration of waste oils 2 is disclosed.
This step is carried out on the fractions leaving the thermodeasphalting step of fig. 4, which is a fractionated distillation, one by one, before sending the removed mineral oil to the hydrofinishing step; namely, oils fed in b) are taken from different fractions of a process for the regeneration of waste, mineral oils. Therefore, either the process is carried out on a single fraction at time or more parallel lines, each of which containing one fraction coming from the thermodeasphalting step, are managed together within the same plant. The fractions cannot be mixed and processed together, without loosing the effects of the previous separation steps, which, in this case, would have to be repeated, with apparent waste of money and energy.
The fraction to be processed is fed from the pipe 44 to the mixer 47, together with methanol, coming from the feed 45. The mixture reaches the decanter 49 through the pipe 48. The liquid in the decanter 49 separates into two layers. A centrifugal separator could be used instead of the decanter 49.
The lighter layer leaves the decanter 49 through the pipe 50 and is sent to the mixer 52, where it is admixed with water, coming from the pipe 46a. In this way, the liquid is washed and the mixture is sent to the decanter 54 through the pipe 53. The lighter layer separated in the decanter 54 is the biological fraction of the oil and is collected from the outlet 61. It can be either sent to the production 3 or be collected and marketed either as solvent or as fuel (biodiesel). Depending on the starting fraction, the biological fraction in the outlet 61 can be a biosolvent (VGO), a spindle lubricant (FLS), a light biolubricant (FLL) or a heavy biolubricant (FLP). The heavier layer leaves the decanter 54 through the pipe 55 and is fed to the packed distillation column 56, where wastewater is discharfged by the pipe 57 and methanol, exiting through the pipe 58, is partially purged in 59 and partially recycled, after a make up 60, therough the pipe 45 to the mixer 47, so reducing the costs for reactants through its recovery.
The heavier layer leaves the decanter 49 through the pipe 51 and is fed to a mixer 62, where also waetr is fed by the pipe 46b to wash the liquid. The mixture leaves the mixer 62 through the pipe 63 and reaches a decanter 64, where the lower layer, containing wastewater, is discharged through the pipe 65 and the top layer, containing purified mineral oil, is collected for next regeneration steps through the pipe 66. A centrifugal separator can be used instead of the decanter 64, so speeding up the separation. The purified mineral oil can be used for producing lubricant mineral bases, even of Group III grade.
Finally, the production of biolubricants 3 is disclosed. This step processes the biosolvents obtained in steps 1 and 2, resulting in their enhancement.
One of the products from treatments 1 and 2, namely the products 9 (biosolvents coming from the treatment of UCO/RUCO 1), and 61 (the biological fraction of the oil to be regenerated from the treatment 2) are fed, through the pipe 67, to the reactor 71, where they are admixed with a catalyst fed through the inlet 68, with an alcohol, possibly a polyalcohol, fed through the inlet 69 and possibly other co-reactants, fed through the inlet 70. Normally, the process is carried out once per each alcohol, so as to get homogeneous products. The catalyst fed through the pipe 68 is preferably a strong base, particularly preferably it is a metal methanoate, most preferably it is sodium methanoate, which leads to the best yield.
Raw methanol is discharged through the pipe 72 and it can be recycled to any step of the inventive process, while the other products are fed, through the pipe 73, to a mixer 74, where they are admixed with water, coming from the pipe 75. The mixture is fed, through the pipe 76, to the decanter 77, where two layers separate.
The heavier layer, containing wastewater, is discharged from the pipe 78.
The lighter layer exits through the pipe 79 and is fed to the stripping column 80, where steam stripping takes place with steam fed from the pipe 81. The top, removed through the pipe 82, separated from wastewater, contains unreacted biosolvents, which are recycled to the tank 9. The bottom leaves the stripping column 80 through the pipe 83 and is fed to the dehydrating column 84, separating wastewater, which is discharged through the pipe 86, and lubricants having biological origin, which are discharged through the pipe 85.
This invention allows a full recovery of a complex of fatty wastes, providing valuable and enhanced products, which can be easily sold. The process gives no wastes to be disposed of and is therefore a completely clean process. It is fast and can be controlled very carefully by skilled people.

The lubricants with biological origin which can be got through this invention exhibit viscosity ranging from 5 to 300 mm²/s, which can be tailored by choosing the suitable alcohols. The use of terpenic alcohols, moreover, can lead to lubricants for use in cosmetics. The following are some examples of biolubricants, with their viscosity:

Used alcohol(s)	Viscosity (at 40 °C) in mm²s
Trimethylpropanol	40 - 45
1-Butanol	6 - 8
1-decanol	10 - 12
Monoethylene glycol	20 - 24
Triethylene glycol	28 - 32
Pentaerythritol	60 - 65
L-menthol	9 - 12
Trimethylpropanol or pentaerythritol + adipic acid as a co-reactant	100 - 500

Anyway, it is understood that the invention should not be considered as limited to the particular arrangement above, which is only an exemplary embodiment thereof, but that a number of variants is possible, all of which being at reach of the skilled person, without therefore departing from the scope of protection of the invention itself, as defined by the following claims.

LIST OF NUMERAL REFERENCES

1: Treatment of used cooking oils and regenerated cooking oils
2: Treatment of the biological content coming from the regeneration of waste oils
3: Production of biolubricants
4: Pipe
5: Pipe
6: Pipe
7: Stream
8: Stream
9: Pipe
10: Stock
11: Pipe
12: Reactor
13: Outlet
14: Reactor
15: Outlet
16: Outlet
17: Outlet
18: Pipe
19: Make up
20: Pipe
21: Decanter
22: Outlet
23: Outlet
24: Distillation step
25: Head fraction (of 24)
26: Bottom fraction (of 24)
27: Heating
28: Plate distillation column
29: Stream
30: Distillation unit
31: Pipe
32: Pipe
33: Distillation column
34: Pipe
35: Pipe
36: Distillation unit
37: Waste
38: Pipe
39: Purge
40: Heating
41: Plate distillation column
42: Outlet
43: Outlet
44: Inlet
45: Inlet
46: Tube (a and b)
47: Mixer
48: Outlet
49: Decanter
50: Tube
51: Tube
52: Mixer
53: Outlet
54: Decanter
55: Pipe
56: Distillation packed column
57: Outlet
58: Tube
59: Vent
60: Make up
61: Pipe (a and b)
62: Mixer
63: Outlet
64: Decanter
65: Tube
66: Tube
67: Pipe
68: Pipe
69: Pipe
70: Pipe
71: Reactor
72: Vent
73: Pipe
74: Mixer
75: Tube
76: Pipe
77: Decanter
78: Pipe
79: Pipe
80: Stripping column
81: Pipe
82: Pipe
83: Pipe
84: Dehydrating column
85: Pipe
86: Product collection

Claims

Process for the regeneration of fatty wastes, including three different feeds, namely a) UCO (used cooking oils)/RUCO (regenerated used cooking oils); b) oils having biological origin, separated from mineral oils under regeneration; and c) solvents and fuels having biological origin, characterised in that feed c) is the product of treatments of feeds a) and b) and in that the three feeds are treated in parallel.
Process according to claim 1), characterised in that oils fed in b) are taken from different fractions of a process for the regeneration of waste, mineral oils.
Process according to claim 2), characterised in that each fraction of a process for the regeneration of mineral oils is processed at a time.
Process according to any previous claim, characterised in that the feed c) is treated any time with an alcohol, which is chosen in order to tailor the viscosity of the end product.
Process according to any previous claim, characterised in that the feed a) contain also animal and/or plant fats.
Process as in any previous claim, characterised in that the waste oils fed in a) and b) are previously transesterified with methanol and are fed through the feed c) as methyl esters.