Recovery of fatty waste

Abstract

A process for recovering fatty waste is disclosed. The process according to the invention provides one or more of the sequential steps of methanolysis, distillation, saponification, and esterification.

Description

[0001] RECOVERY OF FATTY WASTE

[0002] The present invention relates to a method for the recovery of fats , starting from waste emanating from fatty substances and producing a series of commercially useful products , without the emission of pollutants .

[0003] Fats are certainly among the most common food substances . In addition to having a high caloric content , they are substances capable of solubilising and allowing our body to absorb lipophilic substances , such as some proteins and vitamins . Common dietary fats include olive oil, seed oils , butter, lard, and others . Furthermore, some foods contain them together with other substances : this is the case of meat , cured meats , fish, and others .

[0004] Fatty substances are also used in detergency . The saponification of fatty acids leads to the formation of fatty acid salts, usually sodium salts , which have surfactant and emulsifying properties and can be used as soaps . Typically, said soaps are obtained by boiling fatty residues , usually butcher ' s waste, in more or less concentrated solutions of soda (NaOH) , potash (KOH) , and other strongly alkaline substances . In this case, the metal cation binds ionically to the carboxylic ion, making the carboxylic fraction soluble in water, whereas the hydrocarbon fraction can solubilize and bring lipophilic substances into solution . In this way, the lipophilic part of the grime dissolves in the hydrocarbon tail and the soap is then dissolved in water through its ionic, hydrophilic head .

[0005] One of the problems associated with edible fats is that, although they are edible and obviously non-toxic substances , they are practically not soluble in water and do not have particularly short decomposition times, so that after use they tend to build up, for example, in water . Their build up in water leads to the phenomenon known as "fatbergs" : the creation of fatty masses that obstruct the sewers, creating actual plugs that can lead to the bursting of pipes and the emergence of sewage on the streets and in homes . Build up in the soil is a little less problematic, but it can end up polluting groundwater .

[0006] Several solutions have been studied for this type of recovery and the Applicant itself of this application has also filed several patents on the subject, especially aimed at the production of biolubricants . The use of used cooking oils as fuel, the so- called "biodiesels , " is also well known .

[0007] However, to date, the products obtained from the regeneration of fats for food use have modest added value .

[0008] The underlying problem of the invention is to propose a process for recovering fatty waste that overcomes the aforementioned drawbacks and allows for the production of various products of biological origin, useful for industrial use and with a certain added value . This purpose is achieved through a process for recovering fatty waste, consisting of one or more of the following : used cooking oils (UCO) , repurpose used cooking oils (RUCO) , poultry fat, lard oil, butcher ' s waste, seed oils of various origins , characterised in that it provides one or more of the sequential steps of reaction with methanol, distillation, reaction with a strong base, and reaction with an alcohol of the product of said reaction with a strong base The sub claims disclose preferred features of the invention .

[0009] In a preferred embodiment, the reaction with methanol occurs in the presence of strong bases .

[0010] In a preferred embodiment, the process involves a reaction step with methanol, followed by separation of the product into two phases , each of which is subsequently purified .

[0011] In a preferred embodiment, the process involves a reaction step with methanol, followed by separation of the product into two phases , one of which is subjected to washing and distillation to remove the methanol present , the other of which is subsequently purified and the purified portion is reacted with a strong base .

[0012] According to a preferred embodiment, the product of the reaction with a strong base is acidified and subsequently esterified with selected alcohols . According to a preferred embodiment , the selected alcohols are chosen among trimethylpropanol, 1-decanol, 2-ethylhexanol, s-butanol , and isopropanol .

[0013] According to one embodiment, the reaction with methanol is carried out under reflux within a temperature range between 60 and 70 °C .

[0014] In one embodiment , the reaction of the reaction with methanol is carried out for a time between 2 to 6 hours .

[0015] In one embodiment , the product of the reaction with methanol is purified by washing with methyl acetate and / or ethyl acetate . In one embodiment, methyl acetate, ethyl acetate, and methanol are removed by distillation after purification is complete .

[0016] In one embodiment , the product of the reaction with methanol is purified by distillation . Preferably, said distillation is carried out under vacuum . Preferably, the pressure during the vacuum distillation is between 0 . 01 and 0 . 02 bar .

[0017] According to one embodiment , the reaction with a strong base occurs at a temperature between 70 and 90 °C . In one embodiment , the product of the reaction with a strong base is acidified . According to one embodiment, the acidification of the product of the reaction step with a strong base occurs in the presence of H3PO4 .

[0018] In one embodiment , the reaction with an alcohol of the product of the acidification reaction is carried out by selecting the alcohol so as to adjust the viscosity of the resulting biolubricant .

[0019] In one embodiment , the reaction with an alcohol of the product of the acidification reaction is carried out batchwise, feeding one alcohol at a time .

[0020] Additional features and advantages of the invention are, however, more evident from the following detailed description of a preferred embodiment , provided solely by way of example and not limited thereto, and illustrated in the sole attached figure, which shows a schematic representation of a recovery process of fatty waste based on one embodiment of the present invention .

[0021] The attached extremely schematic drawing illustrates the process of recovery of fatty waste .

[0022] Fatty waste contains , but is not necessarily limited to, used cooking oils (UCO) , repurpose used cooking oils (RUCO) , poultry fat, and lard oil, thus recycling a significant amount of nonwater-soluble food waste which currently has to be disposed of with the costs that this entails .

[0023] The reactions to which this fatty waste is subjected are : methanolysis ; purification of the crude biological solvent obtained, through washing or vacuum distillation; distillation of methanol; distillation of ethyl acetate or methyl acetate and methanol; saponification; purification of fatty acids through washing or vacuum distillation, and esterification . These are all relatively simple reactions that require neither expensive equipment nor expensive conditions .

[0024] In 1 , there is the feed of fatty waste, as previously defined, to which methanol is added . The mixture is reacted according to the methanolysis reaction, which preferably occurs in the presence of strong bases, in a special reactor . Preferably, the reaction takes place in the presence of strong bases , such as NaOH or KOH, which are readily available and inexpensive, at a temperature between 50 and 100 °C, preferably between 60 and 70 °C . It is preferable to operate under reflux, so as to further push the reaction, for a period of approximately 1-10 hours , preferably between 2 and 6 hours . Preferably, the methanolysis step is followed by separation of the product into two phases , each of which is subsequently purified .

[0025] In 2 , a product comes out , which can be recovered as such or sent to the next steps . First, product 2 is divided into two layers , 3 , 4 . Layer 3, considered as the crude biosolvent , is purified in 5 ; said purification may occur in two ways : by washing in series with ethyl or methyl acetate and water or by distillation, possibly by vacuum distillation ( 0 . 0133 bar) , so as to reduce temperatures and times , with better purification . The removed part 6 is used as biofeed for bacteria, for the development and maintenance of cultures under ecological conditions . The purified part 7 is made up of biosolvents . Said biosolvents are mostly fatty acid esters . In 8 , the acetyls of methanol and / or ethanol and the methanol are recovered by distillation, so that they can be recycled into the reaction .

[0026] Layer 4 is washed with water and distilled to recover methanol and leads, in 9, to detergents of natural origin .

[0027] The biosolvents in 7 can be sold as such (although they do not have a particularly high added value) or be further processed . In particular, in 10 a strong base, such as NaOH or KOH, and water can be added, leading to a saponification reaction . A temperature between 50 and 100 °C, preferably between 70 and 90 °C, is used, thus adjusting the pH so that it is lower than or equal to 3 . At the end, H3PO4 or citric acid is added . The product which comes out in 11 is divided into two parts . The first part , 12 , is composed of sodium and / or potassium phosphates and / or citrates and can be used as a fertiliser or as a food additive . The remainder, 13, comprises crude fatty acids . These undergo a normal purification step . Such purification can be done, for example, by washing, distillation, vacuum distillation ( 0 . 0133 bar, 380 °C) , crystallisation and the like .

[0028] The purified fatty acids 14 are obtained .

[0029] The fatty acids 14 can be further processed, for example, by adding one or more alcohols , such as trimethylpropanol, 1-decanol, 2-ethylhexanol, 1-decanol, s-butanol, isopropanol or others , to obtain biolubricants 15 . The choice of the specific alcohols to be used determines the final properties of the biolubricant, in particular its viscosity, a very important parameter, as already reported in the prior art .

[0030] The process according to the present invention allows for the disposal, in an environmentally friendly manner, of fatty waste which would cause drawbacks, allowing the production of easily marketable substances and modulating the products obtained according to current needs . The distillation steps allow the recovery of the solvents used for the reactions and for the washings , thus avoiding having to dispose of them, except in minimal quantities after several passes , thus achieving a clear advantage . No pollutants are produced, so that the process can be considered part of the so-called circular economy .

[0031] The products that can be obtained with the process according to the present invention are biologically derived soaps , biologically derived solvents , biologically derived feed for bacteria, biologically derived fertilisers or food additives , biologically derived fatty acids and lubricants, all of which are of considerable commercial interest , with a significant added value it should also be noted that these products are a source of income that replaces what until now had been a loss due to substances that had to be disposed of in some way . It should also be noted that the process according to the present invention can be managed and modulated in order to obtain the most requested products , depending on the moment .

[0032] It is to be understood, however, that the invention is not to be considered limited to the particular arrangement illustrated above, which is only an exemplary embodiment of it , but rather that several variations are possible, all within the knowledge of a person skilled in the art, without hereby going beyond the scope of protection of the invention itself , as defined by the following claims .

[0033] LIST OF REFERENCE SIGNS

[0034] 1 Fatty waste feed

[0035] 2 Methanolysis product

[0036] 3 Upper phase (crude biosolvent )

[0037] 4 Lower phase to be further processed

[0038] 5 biosolvent purification

[0039] 6 Feed for bacteria

[0040] 7 Purified biosolvent 8 Solvent removal by distillation

[0041] 9 Detergents

[0042] 10 Biosolvent processing

[0043] 11 Product

[0044] 12 Fertiliser 13 Crude fatty acids

[0045] 14 Purified fatty acids

[0046] 15 Biolubricants

Claims

CLAIMS1. Process for recovering fatty waste, consisting of one or more of the following: used cooking oils (UCO) , repurpose used cooking oils (RUCO) , poultry fat, lard oil, butcher's waste, seed oils of various origin, characterised in that it provides one or more of the sequential steps of reaction with methanol, distillation, reaction with a strong base, and reaction with an alcohol of the product of said reaction with a strong base.

2. Process as in 1) , characterised in that said reaction with methanol occurs in the presence of strong bases.

3. Process as in 1) or 2) , characterised in that it provides a reaction step with methanol, followed by separation of the product into two phases, each of which is subsequently purified.

4. Process as in 1) or 2) , characterised in that it provides a reaction step with methanol, followed by separation of the product into two phases, one (4) of which is subjected to washing and distillation, to remove the methanol present, the other (3) of which is subsequently purified and the purified portion is reacted with a strong base.

5. Process as in 4) , characterised in that the product of the reaction with a strong base is acidified and subsequently esterified with selected alcohols.

6. Process as in claim 5) , characterised in that the selected alcohols are chosen among trimethylpropanol, 1-decanol, 2- ethylhexanol, 1-decanol, s-butanol, and isopropanol.

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